version: bump snapshot

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

.gitignore

@@ -1,4 +1 @@
 wireguard-go
-vendor
-.gopath
-ireallywantobuildon_linux.go

Makefile

@@ -10,10 +10,10 @@ MAKEFLAGS += --no-print-directory
 generate-version-and-build:
 	@export GIT_CEILING_DIRECTORIES="$(realpath $(CURDIR)/..)" && \
 	tag="$$(git describe --dirty 2>/dev/null)" && \
-	ver="$$(printf 'package device\nconst WireGuardGoVersion = "%s"\n' "$${tag#v}")" && \
-	[ "$$(cat device/version.go 2>/dev/null)" != "$$ver" ] && \
-	echo "$$ver" > device/version.go && \
-	git update-index --assume-unchanged device/version.go || true
+	ver="$$(printf 'package main\nconst Version = "%s"\n' "$$tag")" && \
+	[ "$$(cat version.go 2>/dev/null)" != "$$ver" ] && \
+	echo "$$ver" > version.go && \
+	git update-index --assume-unchanged version.go || true
 	@$(MAKE) wireguard-go
 
 wireguard-go: $(wildcard *.go) $(wildcard */*.go)
@@ -22,7 +22,10 @@ wireguard-go: $(wildcard *.go) $(wildcard */*.go)
 install: wireguard-go
 	@install -v -d "$(DESTDIR)$(BINDIR)" && install -v -m 0755 "$<" "$(DESTDIR)$(BINDIR)/wireguard-go"
 
+test:
+	go test -v ./...
+
 clean:
 	rm -f wireguard-go
 
-.PHONY: all clean install generate-version-and-build
+.PHONY: all clean test install generate-version-and-build

README.md

@@ -26,7 +26,7 @@ To run with more logging you may set the environment variable `LOG_LEVEL=debug`.
 
 ### Linux
 
-This will run on Linux; however **YOU SHOULD NOT RUN THIS ON LINUX**. Instead use the kernel module; see the [installation page](https://www.wireguard.com/install/) for instructions.
+This will run on Linux; however you should instead use the kernel module, which is faster and better integrated into the OS. See the [installation page](https://www.wireguard.com/install/) for instructions.
 
 ### macOS
 
@@ -46,7 +46,7 @@ This will run on OpenBSD. It does not yet support sticky sockets. Fwmark is mapp
 
 ## Building
 
-This requires an installation of [go](https://golang.org) ≥ 1.12.
+This requires an installation of [go](https://golang.org) ≥ 1.13.
 
 ```
 $ git clone https://git.zx2c4.com/wireguard-go
@@ -56,7 +56,7 @@ $ make
 
 ## License
 
-    Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+    Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
     
     Permission is hereby granted, free of charge, to any person obtaining a copy of
     this software and associated documentation files (the "Software"), to deal in

conn/boundif_android.go

@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package conn
+
+func (bind *nativeBind) PeekLookAtSocketFd4() (fd int, err error) {
+	sysconn, err := bind.ipv4.SyscallConn()
+	if err != nil {
+		return -1, err
+	}
+	err = sysconn.Control(func(f uintptr) {
+		fd = int(f)
+	})
+	if err != nil {
+		return -1, err
+	}
+	return
+}
+
+func (bind *nativeBind) PeekLookAtSocketFd6() (fd int, err error) {
+	sysconn, err := bind.ipv6.SyscallConn()
+	if err != nil {
+		return -1, err
+	}
+	err = sysconn.Control(func(f uintptr) {
+		fd = int(f)
+	})
+	if err != nil {
+		return -1, err
+	}
+	return
+}

conn/boundif_windows.go

@@ -1,13 +1,12 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 import (
 	"encoding/binary"
-	"errors"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
@@ -18,17 +17,13 @@ const (
 	sockoptIPV6_UNICAST_IF = 31
 )
 
-func (device *Device) BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error {
+func (bind *nativeBind) BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error {
 	/* MSDN says for IPv4 this needs to be in net byte order, so that it's like an IP address with leading zeros. */
 	bytes := make([]byte, 4)
 	binary.BigEndian.PutUint32(bytes, interfaceIndex)
 	interfaceIndex = *(*uint32)(unsafe.Pointer(&bytes[0]))
 
-	if device.net.bind == nil {
-		return errors.New("Bind is not yet initialized")
-	}
-
-	sysconn, err := device.net.bind.(*nativeBind).ipv4.SyscallConn()
+	sysconn, err := bind.ipv4.SyscallConn()
 	if err != nil {
 		return err
 	}
@@ -41,12 +36,12 @@ func (device *Device) BindSocketToInterface4(interfaceIndex uint32, blackhole bo
 	if err != nil {
 		return err
 	}
-	device.net.bind.(*nativeBind).blackhole4 = blackhole
+	bind.blackhole4 = blackhole
 	return nil
 }
 
-func (device *Device) BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error {
-	sysconn, err := device.net.bind.(*nativeBind).ipv6.SyscallConn()
+func (bind *nativeBind) BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error {
+	sysconn, err := bind.ipv6.SyscallConn()
 	if err != nil {
 		return err
 	}
@@ -59,6 +54,6 @@ func (device *Device) BindSocketToInterface6(interfaceIndex uint32, blackhole bo
 	if err != nil {
 		return err
 	}
-	device.net.bind.(*nativeBind).blackhole6 = blackhole
+	bind.blackhole6 = blackhole
 	return nil
 }

conn/conn.go

@@ -0,0 +1,111 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+// Package conn implements WireGuard's network connections.
+package conn
+
+import (
+	"errors"
+	"net"
+	"strings"
+)
+
+// A Bind listens on a port for both IPv6 and IPv4 UDP traffic.
+//
+// A Bind interface may also be a PeekLookAtSocketFd or BindSocketToInterface,
+// depending on the platform-specific implementation.
+type Bind interface {
+	// LastMark reports the last mark set for this Bind.
+	LastMark() uint32
+
+	// SetMark sets the mark for each packet sent through this Bind.
+	// This mark is passed to the kernel as the socket option SO_MARK.
+	SetMark(mark uint32) error
+
+	// ReceiveIPv6 reads an IPv6 UDP packet into b.
+	//
+	// It reports the number of bytes read, n,
+	// the packet source address ep,
+	// and any error.
+	ReceiveIPv6(b []byte) (n int, ep Endpoint, err error)
+
+	// ReceiveIPv4 reads an IPv4 UDP packet into b.
+	//
+	// It reports the number of bytes read, n,
+	// the packet source address ep,
+	// and any error.
+	ReceiveIPv4(b []byte) (n int, ep Endpoint, err error)
+
+	// Send writes a packet b to address ep.
+	Send(b []byte, ep Endpoint) error
+
+	// Close closes the Bind connection.
+	Close() error
+}
+
+// CreateBind creates a Bind bound to a port.
+//
+// The value actualPort reports the actual port number the Bind
+// object gets bound to.
+func CreateBind(port uint16) (b Bind, actualPort uint16, err error) {
+	return createBind(port)
+}
+
+// BindSocketToInterface is implemented by Bind objects that support being
+// tied to a single network interface. Used by wireguard-windows.
+type BindSocketToInterface interface {
+	BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error
+	BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error
+}
+
+// PeekLookAtSocketFd is implemented by Bind objects that support having their
+// file descriptor peeked at. Used by wireguard-android.
+type PeekLookAtSocketFd interface {
+	PeekLookAtSocketFd4() (fd int, err error)
+	PeekLookAtSocketFd6() (fd int, err error)
+}
+
+// An Endpoint maintains the source/destination caching for a peer.
+//
+//	dst : the remote address of a peer ("endpoint" in uapi terminology)
+//	src : the local address from which datagrams originate going to the peer
+type Endpoint interface {
+	ClearSrc()           // clears the source address
+	SrcToString() string // returns the local source address (ip:port)
+	DstToString() string // returns the destination address (ip:port)
+	DstToBytes() []byte  // used for mac2 cookie calculations
+	DstIP() net.IP
+	SrcIP() net.IP
+}
+
+func parseEndpoint(s string) (*net.UDPAddr, error) {
+	// ensure that the host is an IP address
+
+	host, _, err := net.SplitHostPort(s)
+	if err != nil {
+		return nil, err
+	}
+	if i := strings.LastIndexByte(host, '%'); i > 0 && strings.IndexByte(host, ':') >= 0 {
+		// Remove the scope, if any. ResolveUDPAddr below will use it, but here we're just
+		// trying to make sure with a small sanity test that this is a real IP address and
+		// not something that's likely to incur DNS lookups.
+		host = host[:i]
+	}
+	if ip := net.ParseIP(host); ip == nil {
+		return nil, errors.New("Failed to parse IP address: " + host)
+	}
+
+	// parse address and port
+
+	addr, err := net.ResolveUDPAddr("udp", s)
+	if err != nil {
+		return nil, err
+	}
+	ip4 := addr.IP.To4()
+	if ip4 != nil {
+		addr.IP = ip4
+	}
+	return addr, err
+}

conn/conn_default.go

@@ -2,14 +2,14 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 import (
+	"errors"
 	"net"
-	"os"
 	"syscall"
 )
 
@@ -37,7 +37,7 @@ func CreateEndpoint(s string) (Endpoint, error) {
 	return (*NativeEndpoint)(addr), err
 }
 
-func (_ *NativeEndpoint) ClearSrc() {}
+func (*NativeEndpoint) ClearSrc() {}
 
 func (e *NativeEndpoint) DstIP() net.IP {
 	return (*net.UDPAddr)(e).IP
@@ -67,16 +67,12 @@ func (e *NativeEndpoint) SrcToString() string {
 }
 
 func listenNet(network string, port int) (*net.UDPConn, int, error) {
-
-	// listen
-
 	conn, err := net.ListenUDP(network, &net.UDPAddr{Port: port})
 	if err != nil {
 		return nil, 0, err
 	}
 
-	// retrieve port
-
+	// Retrieve port.
 	laddr := conn.LocalAddr()
 	uaddr, err := net.ResolveUDPAddr(
 		laddr.Network(),
@@ -88,31 +84,26 @@ func listenNet(network string, port int) (*net.UDPConn, int, error) {
 	return conn, uaddr.Port, nil
 }
 
-func extractErrno(err error) error {
-	opErr, ok := err.(*net.OpError)
-	if !ok {
-		return nil
-	}
-	syscallErr, ok := opErr.Err.(*os.SyscallError)
-	if !ok {
-		return nil
-	}
-	return syscallErr.Err
-}
-
-func CreateBind(uport uint16, device *Device) (Bind, uint16, error) {
+func createBind(uport uint16) (Bind, uint16, error) {
 	var err error
 	var bind nativeBind
+	var tries int
 
+again:
 	port := int(uport)
 
 	bind.ipv4, port, err = listenNet("udp4", port)
-	if err != nil && extractErrno(err) != syscall.EAFNOSUPPORT {
+	if err != nil && !errors.Is(err, syscall.EAFNOSUPPORT) {
 		return nil, 0, err
 	}
 
 	bind.ipv6, port, err = listenNet("udp6", port)
-	if err != nil && extractErrno(err) != syscall.EAFNOSUPPORT {
+	if uport == 0 && err != nil && errors.Is(err, syscall.EADDRINUSE) && tries < 100 {
+		bind.ipv4.Close()
+		tries++
+		goto again
+	}
+	if err != nil && !errors.Is(err, syscall.EAFNOSUPPORT) {
 		bind.ipv4.Close()
 		bind.ipv4 = nil
 		return nil, 0, err
@@ -135,6 +126,8 @@ func (bind *nativeBind) Close() error {
 	return err2
 }
 
+func (bind *nativeBind) LastMark() uint32 { return 0 }
+
 func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
 	if bind.ipv4 == nil {
 		return 0, nil, syscall.EAFNOSUPPORT

conn/conn_linux.go

@@ -2,19 +2,10 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
- *
- * This implements userspace semantics of "sticky sockets", modeled after
- * WireGuard's kernelspace implementation. This is more or less a straight port
- * of the sticky-sockets.c example code:
- * https://git.zx2c4.com/wireguard-tools/tree/contrib/sticky-sockets/sticky-sockets.c
- *
- * Currently there is no way to achieve this within the net package:
- * See e.g. https://github.com/golang/go/issues/17930
- * So this code is remains platform dependent.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 import (
 	"errors"
@@ -25,16 +16,11 @@ import (
 	"unsafe"
 
 	"golang.org/x/sys/unix"
-	"golang.zx2c4.com/wireguard/rwcancel"
-)
-
-const (
-	FD_ERR = -1
 )
 
 type IPv4Source struct {
-	src     [4]byte
-	ifindex int32
+	Src     [4]byte
+	Ifindex int32
 }
 
 type IPv6Source struct {
@@ -49,6 +35,10 @@ type NativeEndpoint struct {
 	isV6 bool
 }
 
+func (endpoint *NativeEndpoint) Src4() *IPv4Source         { return endpoint.src4() }
+func (endpoint *NativeEndpoint) Dst4() *unix.SockaddrInet4 { return endpoint.dst4() }
+func (endpoint *NativeEndpoint) IsV6() bool                { return endpoint.isV6 }
+
 func (endpoint *NativeEndpoint) src4() *IPv4Source {
 	return (*IPv4Source)(unsafe.Pointer(&endpoint.src[0]))
 }
@@ -68,9 +58,8 @@ func (endpoint *NativeEndpoint) dst6() *unix.SockaddrInet6 {
 type nativeBind struct {
 	sock4    int
 	sock6    int
-	netlinkSock   int
-	netlinkCancel *rwcancel.RWCancel
 	lastMark uint32
+	closing  sync.RWMutex
 }
 
 var _ Endpoint = (*NativeEndpoint)(nil)
@@ -111,59 +100,34 @@ func CreateEndpoint(s string) (Endpoint, error) {
 	return nil, errors.New("Invalid IP address")
 }
 
-func createNetlinkRouteSocket() (int, error) {
-	sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, unix.NETLINK_ROUTE)
-	if err != nil {
-		return -1, err
-	}
-	saddr := &unix.SockaddrNetlink{
-		Family: unix.AF_NETLINK,
-		Groups: uint32(1 << (unix.RTNLGRP_IPV4_ROUTE - 1)),
-	}
-	err = unix.Bind(sock, saddr)
-	if err != nil {
-		unix.Close(sock)
-		return -1, err
-	}
-	return sock, nil
-
-}
-
-func CreateBind(port uint16, device *Device) (*nativeBind, uint16, error) {
+func createBind(port uint16) (Bind, uint16, error) {
 	var err error
 	var bind nativeBind
 	var newPort uint16
+	var tries int
+	originalPort := port
 
-	bind.netlinkSock, err = createNetlinkRouteSocket()
-	if err != nil {
-		return nil, 0, err
-	}
-	bind.netlinkCancel, err = rwcancel.NewRWCancel(bind.netlinkSock)
-	if err != nil {
-		unix.Close(bind.netlinkSock)
-		return nil, 0, err
-	}
-
-	go bind.routineRouteListener(device)
-
-	// attempt ipv6 bind, update port if successful
-
+again:
+	port = originalPort
+	// Attempt ipv6 bind, update port if successful.
 	bind.sock6, newPort, err = create6(port)
 	if err != nil {
 		if err != syscall.EAFNOSUPPORT {
-			bind.netlinkCancel.Cancel()
 			return nil, 0, err
 		}
 	} else {
 		port = newPort
 	}
 
-	// attempt ipv4 bind, update port if successful
-
+	// Attempt ipv4 bind, update port if successful.
 	bind.sock4, newPort, err = create4(port)
 	if err != nil {
+		if originalPort == 0 && err == syscall.EADDRINUSE && tries < 100 {
+			unix.Close(bind.sock6)
+			tries++
+			goto again
+		}
 		if err != syscall.EAFNOSUPPORT {
-			bind.netlinkCancel.Cancel()
 			unix.Close(bind.sock6)
 			return nil, 0, err
 		}
@@ -171,14 +135,21 @@ func CreateBind(port uint16, device *Device) (*nativeBind, uint16, error) {
 		port = newPort
 	}
 
-	if bind.sock4 == FD_ERR && bind.sock6 == FD_ERR {
+	if bind.sock4 == -1 && bind.sock6 == -1 {
 		return nil, 0, errors.New("ipv4 and ipv6 not supported")
 	}
 
 	return &bind, port, nil
 }
 
+func (bind *nativeBind) LastMark() uint32 {
+	return bind.lastMark
+}
+
 func (bind *nativeBind) SetMark(value uint32) error {
+	bind.closing.RLock()
+	defer bind.closing.RUnlock()
+
 	if bind.sock6 != -1 {
 		err := unix.SetsockoptInt(
 			bind.sock6,
@@ -209,35 +180,40 @@ func (bind *nativeBind) SetMark(value uint32) error {
 	return nil
 }
 
-func closeUnblock(fd int) error {
-	// shutdown to unblock readers and writers
-	unix.Shutdown(fd, unix.SHUT_RDWR)
-	return unix.Close(fd)
-}
-
 func (bind *nativeBind) Close() error {
-	var err1, err2, err3 error
+	var err1, err2 error
+	bind.closing.RLock()
 	if bind.sock6 != -1 {
-		err1 = closeUnblock(bind.sock6)
+		unix.Shutdown(bind.sock6, unix.SHUT_RDWR)
 	}
 	if bind.sock4 != -1 {
-		err2 = closeUnblock(bind.sock4)
+		unix.Shutdown(bind.sock4, unix.SHUT_RDWR)
 	}
-	err3 = bind.netlinkCancel.Cancel()
+	bind.closing.RUnlock()
+	bind.closing.Lock()
+	if bind.sock6 != -1 {
+		err1 = unix.Close(bind.sock6)
+		bind.sock6 = -1
+	}
+	if bind.sock4 != -1 {
+		err2 = unix.Close(bind.sock4)
+		bind.sock4 = -1
+	}
+	bind.closing.Unlock()
 
 	if err1 != nil {
 		return err1
 	}
-	if err2 != nil {
 	return err2
-	}
-	return err3
 }
 
 func (bind *nativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
+	bind.closing.RLock()
+	defer bind.closing.RUnlock()
+
 	var end NativeEndpoint
 	if bind.sock6 == -1 {
-		return 0, nil, syscall.EAFNOSUPPORT
+		return 0, nil, NetErrClosed
 	}
 	n, err := receive6(
 		bind.sock6,
@@ -248,9 +224,12 @@ func (bind *nativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
 }
 
 func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
+	bind.closing.RLock()
+	defer bind.closing.RUnlock()
+
 	var end NativeEndpoint
 	if bind.sock4 == -1 {
-		return 0, nil, syscall.EAFNOSUPPORT
+		return 0, nil, NetErrClosed
 	}
 	n, err := receive4(
 		bind.sock4,
@@ -261,15 +240,18 @@ func (bind *nativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
 }
 
 func (bind *nativeBind) Send(buff []byte, end Endpoint) error {
+	bind.closing.RLock()
+	defer bind.closing.RUnlock()
+
 	nend := end.(*NativeEndpoint)
 	if !nend.isV6 {
 		if bind.sock4 == -1 {
-			return syscall.EAFNOSUPPORT
+			return NetErrClosed
 		}
 		return send4(bind.sock4, nend, buff)
 	} else {
 		if bind.sock6 == -1 {
-			return syscall.EAFNOSUPPORT
+			return NetErrClosed
 		}
 		return send6(bind.sock6, nend, buff)
 	}
@@ -278,10 +260,10 @@ func (bind *nativeBind) Send(buff []byte, end Endpoint) error {
 func (end *NativeEndpoint) SrcIP() net.IP {
 	if !end.isV6 {
 		return net.IPv4(
-			end.src4().src[0],
-			end.src4().src[1],
-			end.src4().src[2],
-			end.src4().src[3],
+			end.src4().Src[0],
+			end.src4().Src[1],
+			end.src4().Src[2],
+			end.src4().Src[3],
 		)
 	} else {
 		return end.src6().src[:]
@@ -358,7 +340,7 @@ func create4(port uint16) (int, uint16, error) {
 	)
 
 	if err != nil {
-		return FD_ERR, 0, err
+		return -1, 0, err
 	}
 
 	addr := unix.SockaddrInet4{
@@ -368,15 +350,6 @@ func create4(port uint16) (int, uint16, error) {
 	// set sockopts and bind
 
 	if err := func() error {
-		if err := unix.SetsockoptInt(
-			fd,
-			unix.SOL_SOCKET,
-			unix.SO_REUSEADDR,
-			1,
-		); err != nil {
-			return err
-		}
-
 		if err := unix.SetsockoptInt(
 			fd,
 			unix.IPPROTO_IP,
@@ -389,7 +362,7 @@ func create4(port uint16) (int, uint16, error) {
 		return unix.Bind(fd, &addr)
 	}(); err != nil {
 		unix.Close(fd)
-		return FD_ERR, 0, err
+		return -1, 0, err
 	}
 
 	sa, err := unix.Getsockname(fd)
@@ -411,7 +384,7 @@ func create6(port uint16) (int, uint16, error) {
 	)
 
 	if err != nil {
-		return FD_ERR, 0, err
+		return -1, 0, err
 	}
 
 	// set sockopts and bind
@@ -421,16 +394,6 @@ func create6(port uint16) (int, uint16, error) {
 	}
 
 	if err := func() error {
-
-		if err := unix.SetsockoptInt(
-			fd,
-			unix.SOL_SOCKET,
-			unix.SO_REUSEADDR,
-			1,
-		); err != nil {
-			return err
-		}
-
 		if err := unix.SetsockoptInt(
 			fd,
 			unix.IPPROTO_IPV6,
@@ -453,7 +416,7 @@ func create6(port uint16) (int, uint16, error) {
 
 	}(); err != nil {
 		unix.Close(fd)
-		return FD_ERR, 0, err
+		return -1, 0, err
 	}
 
 	sa, err := unix.Getsockname(fd)
@@ -478,8 +441,8 @@ func send4(sock int, end *NativeEndpoint, buff []byte) error {
 			Len:   unix.SizeofInet4Pktinfo + unix.SizeofCmsghdr,
 		},
 		unix.Inet4Pktinfo{
-			Spec_dst: end.src4().src,
-			Ifindex:  end.src4().ifindex,
+			Spec_dst: end.src4().Src,
+			Ifindex:  end.src4().Ifindex,
 		},
 	}
 
@@ -573,8 +536,8 @@ func receive4(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 	if cmsg.cmsghdr.Level == unix.IPPROTO_IP &&
 		cmsg.cmsghdr.Type == unix.IP_PKTINFO &&
 		cmsg.cmsghdr.Len >= unix.SizeofInet4Pktinfo {
-		end.src4().src = cmsg.pktinfo.Spec_dst
-		end.src4().ifindex = cmsg.pktinfo.Ifindex
+		end.src4().Src = cmsg.pktinfo.Spec_dst
+		end.src4().Ifindex = cmsg.pktinfo.Ifindex
 	}
 
 	return size, nil
@@ -611,156 +574,3 @@ func receive6(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 
 	return size, nil
 }
-
-func (bind *nativeBind) routineRouteListener(device *Device) {
-	type peerEndpointPtr struct {
-		peer     *Peer
-		endpoint *Endpoint
-	}
-	var reqPeer map[uint32]peerEndpointPtr
-	var reqPeerLock sync.Mutex
-
-	defer unix.Close(bind.netlinkSock)
-
-	for msg := make([]byte, 1<<16); ; {
-		var err error
-		var msgn int
-		for {
-			msgn, _, _, _, err = unix.Recvmsg(bind.netlinkSock, msg[:], nil, 0)
-			if err == nil || !rwcancel.RetryAfterError(err) {
-				break
-			}
-			if !bind.netlinkCancel.ReadyRead() {
-				return
-			}
-		}
-		if err != nil {
-			return
-		}
-
-		for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
-
-			hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
-
-			if uint(hdr.Len) > uint(len(remain)) {
-				break
-			}
-
-			switch hdr.Type {
-			case unix.RTM_NEWROUTE, unix.RTM_DELROUTE:
-				if hdr.Seq <= MaxPeers && hdr.Seq > 0 {
-					if uint(len(remain)) < uint(hdr.Len) {
-						break
-					}
-					if hdr.Len > unix.SizeofNlMsghdr+unix.SizeofRtMsg {
-						attr := remain[unix.SizeofNlMsghdr+unix.SizeofRtMsg:]
-						for {
-							if uint(len(attr)) < uint(unix.SizeofRtAttr) {
-								break
-							}
-							attrhdr := *(*unix.RtAttr)(unsafe.Pointer(&attr[0]))
-							if attrhdr.Len < unix.SizeofRtAttr || uint(len(attr)) < uint(attrhdr.Len) {
-								break
-							}
-							if attrhdr.Type == unix.RTA_OIF && attrhdr.Len == unix.SizeofRtAttr+4 {
-								ifidx := *(*uint32)(unsafe.Pointer(&attr[unix.SizeofRtAttr]))
-								reqPeerLock.Lock()
-								if reqPeer == nil {
-									reqPeerLock.Unlock()
-									break
-								}
-								pePtr, ok := reqPeer[hdr.Seq]
-								reqPeerLock.Unlock()
-								if !ok {
-									break
-								}
-								pePtr.peer.Lock()
-								if &pePtr.peer.endpoint != pePtr.endpoint {
-									pePtr.peer.Unlock()
-									break
-								}
-								if uint32(pePtr.peer.endpoint.(*NativeEndpoint).src4().ifindex) == ifidx {
-									pePtr.peer.Unlock()
-									break
-								}
-								pePtr.peer.endpoint.(*NativeEndpoint).ClearSrc()
-								pePtr.peer.Unlock()
-							}
-							attr = attr[attrhdr.Len:]
-						}
-					}
-					break
-				}
-				reqPeerLock.Lock()
-				reqPeer = make(map[uint32]peerEndpointPtr)
-				reqPeerLock.Unlock()
-				go func() {
-					device.peers.RLock()
-					i := uint32(1)
-					for _, peer := range device.peers.keyMap {
-						peer.RLock()
-						if peer.endpoint == nil || peer.endpoint.(*NativeEndpoint) == nil {
-							peer.RUnlock()
-							continue
-						}
-						if peer.endpoint.(*NativeEndpoint).isV6 || peer.endpoint.(*NativeEndpoint).src4().ifindex == 0 {
-							peer.RUnlock()
-							break
-						}
-						nlmsg := struct {
-							hdr     unix.NlMsghdr
-							msg     unix.RtMsg
-							dsthdr  unix.RtAttr
-							dst     [4]byte
-							srchdr  unix.RtAttr
-							src     [4]byte
-							markhdr unix.RtAttr
-							mark    uint32
-						}{
-							unix.NlMsghdr{
-								Type:  uint16(unix.RTM_GETROUTE),
-								Flags: unix.NLM_F_REQUEST,
-								Seq:   i,
-							},
-							unix.RtMsg{
-								Family:  unix.AF_INET,
-								Dst_len: 32,
-								Src_len: 32,
-							},
-							unix.RtAttr{
-								Len:  8,
-								Type: unix.RTA_DST,
-							},
-							peer.endpoint.(*NativeEndpoint).dst4().Addr,
-							unix.RtAttr{
-								Len:  8,
-								Type: unix.RTA_SRC,
-							},
-							peer.endpoint.(*NativeEndpoint).src4().src,
-							unix.RtAttr{
-								Len:  8,
-								Type: unix.RTA_MARK,
-							},
-							uint32(bind.lastMark),
-						}
-						nlmsg.hdr.Len = uint32(unsafe.Sizeof(nlmsg))
-						reqPeerLock.Lock()
-						reqPeer[i] = peerEndpointPtr{
-							peer:     peer,
-							endpoint: &peer.endpoint,
-						}
-						reqPeerLock.Unlock()
-						peer.RUnlock()
-						i++
-						_, err := bind.netlinkCancel.Write((*[unsafe.Sizeof(nlmsg)]byte)(unsafe.Pointer(&nlmsg))[:])
-						if err != nil {
-							break
-						}
-					}
-					device.peers.RUnlock()
-				}()
-			}
-			remain = remain[hdr.Len:]
-		}
-	}
-}

conn/mark_default.go

@@ -2,10 +2,10 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 func (bind *nativeBind) SetMark(mark uint32) error {
 	return nil

conn/mark_unix.go

@@ -2,10 +2,10 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
-package device
+package conn
 
 import (
 	"runtime"

conn/net_err_closed.go

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package conn
+
+import _ "unsafe"
+
+//TODO: replace this with net.ErrClosed for Go 1.16
+
+//go:linkname NetErrClosed internal/poll.ErrNetClosing
+var NetErrClosed error

device/alignment_test.go

@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"reflect"
+	"testing"
+	"unsafe"
+)
+
+func checkAlignment(t *testing.T, name string, offset uintptr) {
+	t.Helper()
+	if offset%8 != 0 {
+		t.Errorf("offset of %q within struct is %d bytes, which does not align to 64-bit word boundaries (missing %d bytes). Atomic operations will crash on 32-bit systems.", name, offset, 8-(offset%8))
+	}
+}
+
+// TestPeerAlignment checks that atomically-accessed fields are
+// aligned to 64-bit boundaries, as required by the atomic package.
+//
+// Unfortunately, violating this rule on 32-bit platforms results in a
+// hard segfault at runtime.
+func TestPeerAlignment(t *testing.T) {
+	var p Peer
+
+	typ := reflect.TypeOf(&p).Elem()
+	t.Logf("Peer type size: %d, with fields:", typ.Size())
+	for i := 0; i < typ.NumField(); i++ {
+		field := typ.Field(i)
+		t.Logf("\t%30s\toffset=%3v\t(type size=%3d, align=%d)",
+			field.Name,
+			field.Offset,
+			field.Type.Size(),
+			field.Type.Align(),
+		)
+	}
+
+	checkAlignment(t, "Peer.stats", unsafe.Offsetof(p.stats))
+	checkAlignment(t, "Peer.isRunning", unsafe.Offsetof(p.isRunning))
+}
+
+// TestDeviceAlignment checks that atomically-accessed fields are
+// aligned to 64-bit boundaries, as required by the atomic package.
+//
+// Unfortunately, violating this rule on 32-bit platforms results in a
+// hard segfault at runtime.
+func TestDeviceAlignment(t *testing.T) {
+	var d Device
+
+	typ := reflect.TypeOf(&d).Elem()
+	t.Logf("Device type size: %d, with fields:", typ.Size())
+	for i := 0; i < typ.NumField(); i++ {
+		field := typ.Field(i)
+		t.Logf("\t%30s\toffset=%3v\t(type size=%3d, align=%d)",
+			field.Name,
+			field.Offset,
+			field.Type.Size(),
+			field.Type.Align(),
+		)
+	}
+	checkAlignment(t, "Device.rate.underLoadUntil", unsafe.Offsetof(d.rate)+unsafe.Offsetof(d.rate.underLoadUntil))
+}

device/allowedips.go

@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
+	"container/list"
 	"errors"
 	"math/bits"
 	"net"
@@ -14,15 +15,13 @@ import (
 )
 
 type trieEntry struct {
-	cidr  uint
 	child        [2]*trieEntry
-	bits  net.IP
 	peer         *Peer
-
-	// index of "branching" bit
-
+	bits         net.IP
+	cidr         uint
 	bit_at_byte  uint
 	bit_at_shift uint
+	perPeerElem  *list.Element
 }
 
 func isLittleEndian() bool {
@@ -69,6 +68,17 @@ func commonBits(ip1 net.IP, ip2 net.IP) uint {
 	}
 }
 
+func (node *trieEntry) addToPeerEntries() {
+	node.perPeerElem = node.peer.trieEntries.PushBack(node)
+}
+
+func (node *trieEntry) removeFromPeerEntries() {
+	if node.perPeerElem != nil {
+		node.peer.trieEntries.Remove(node.perPeerElem)
+		node.perPeerElem = nil
+	}
+}
+
 func (node *trieEntry) removeByPeer(p *Peer) *trieEntry {
 	if node == nil {
 		return node
@@ -85,6 +95,7 @@ func (node *trieEntry) removeByPeer(p *Peer) *trieEntry {
 
 	// remove peer & merge
 
+	node.removeFromPeerEntries()
 	node.peer = nil
 	if node.child[0] == nil {
 		return node.child[1]
@@ -96,18 +107,28 @@ func (node *trieEntry) choose(ip net.IP) byte {
 	return (ip[node.bit_at_byte] >> node.bit_at_shift) & 1
 }
 
+func (node *trieEntry) maskSelf() {
+	mask := net.CIDRMask(int(node.cidr), len(node.bits)*8)
+	for i := 0; i < len(mask); i++ {
+		node.bits[i] &= mask[i]
+	}
+}
+
 func (node *trieEntry) insert(ip net.IP, cidr uint, peer *Peer) *trieEntry {
 
 	// at leaf
 
 	if node == nil {
-		return &trieEntry{
+		node := &trieEntry{
 			bits:         ip,
 			peer:         peer,
 			cidr:         cidr,
 			bit_at_byte:  cidr / 8,
 			bit_at_shift: 7 - (cidr % 8),
 		}
+		node.maskSelf()
+		node.addToPeerEntries()
+		return node
 	}
 
 	// traverse deeper
@@ -115,7 +136,9 @@ func (node *trieEntry) insert(ip net.IP, cidr uint, peer *Peer) *trieEntry {
 	common := commonBits(node.bits, ip)
 	if node.cidr <= cidr && common >= node.cidr {
 		if node.cidr == cidr {
+			node.removeFromPeerEntries()
 			node.peer = peer
+			node.addToPeerEntries()
 			return node
 		}
 		bit := node.choose(ip)
@@ -132,6 +155,8 @@ func (node *trieEntry) insert(ip net.IP, cidr uint, peer *Peer) *trieEntry {
 		bit_at_byte:  cidr / 8,
 		bit_at_shift: 7 - (cidr % 8),
 	}
+	newNode.maskSelf()
+	newNode.addToPeerEntries()
 
 	cidr = min(cidr, common)
 
@@ -146,12 +171,13 @@ func (node *trieEntry) insert(ip net.IP, cidr uint, peer *Peer) *trieEntry {
 	// create new parent for node & newNode
 
 	parent := &trieEntry{
-		bits:         ip,
+		bits:         append([]byte{}, ip...),
 		peer:         nil,
 		cidr:         cidr,
 		bit_at_byte:  cidr / 8,
 		bit_at_shift: 7 - (cidr % 8),
 	}
+	parent.maskSelf()
 
 	bit := parent.choose(ip)
 	parent.child[bit] = newNode
@@ -176,44 +202,22 @@ func (node *trieEntry) lookup(ip net.IP) *Peer {
 	return found
 }
 
-func (node *trieEntry) entriesForPeer(p *Peer, results []net.IPNet) []net.IPNet {
-	if node == nil {
-		return results
-	}
-	if node.peer == p {
-		mask := net.CIDRMask(int(node.cidr), len(node.bits)*8)
-		results = append(results, net.IPNet{
-			Mask: mask,
-			IP:   node.bits.Mask(mask),
-		})
-	}
-	results = node.child[0].entriesForPeer(p, results)
-	results = node.child[1].entriesForPeer(p, results)
-	return results
-}
-
 type AllowedIPs struct {
 	IPv4  *trieEntry
 	IPv6  *trieEntry
 	mutex sync.RWMutex
 }
 
-func (table *AllowedIPs) EntriesForPeer(peer *Peer) []net.IPNet {
+func (table *AllowedIPs) EntriesForPeer(peer *Peer, cb func(ip net.IP, cidr uint) bool) {
 	table.mutex.RLock()
 	defer table.mutex.RUnlock()
 
-	allowed := make([]net.IPNet, 0, 10)
-	allowed = table.IPv4.entriesForPeer(peer, allowed)
-	allowed = table.IPv6.entriesForPeer(peer, allowed)
-	return allowed
-}
-
-func (table *AllowedIPs) Reset() {
-	table.mutex.Lock()
-	defer table.mutex.Unlock()
-
-	table.IPv4 = nil
-	table.IPv6 = nil
+	for elem := peer.trieEntries.Front(); elem != nil; elem = elem.Next() {
+		node := elem.Value.(*trieEntry)
+		if !cb(node.bits, node.cidr) {
+			return
+		}
+	}
 }
 
 func (table *AllowedIPs) RemoveByPeer(peer *Peer) {

device/allowedips_rand_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -73,11 +73,11 @@ func TestTrieRandomIPv4(t *testing.T) {
 
 	const AddressLength = 4
 
-	for n := 0; n < NumberOfPeers; n += 1 {
+	for n := 0; n < NumberOfPeers; n++ {
 		peers = append(peers, &Peer{})
 	}
 
-	for n := 0; n < NumberOfAddresses; n += 1 {
+	for n := 0; n < NumberOfAddresses; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		cidr := uint(rand.Uint32() % (AddressLength * 8))
@@ -86,7 +86,7 @@ func TestTrieRandomIPv4(t *testing.T) {
 		slow = slow.Insert(addr[:], cidr, peers[index])
 	}
 
-	for n := 0; n < NumberOfTests; n += 1 {
+	for n := 0; n < NumberOfTests; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		peer1 := slow.Lookup(addr[:])
@@ -106,11 +106,11 @@ func TestTrieRandomIPv6(t *testing.T) {
 
 	const AddressLength = 16
 
-	for n := 0; n < NumberOfPeers; n += 1 {
+	for n := 0; n < NumberOfPeers; n++ {
 		peers = append(peers, &Peer{})
 	}
 
-	for n := 0; n < NumberOfAddresses; n += 1 {
+	for n := 0; n < NumberOfAddresses; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		cidr := uint(rand.Uint32() % (AddressLength * 8))
@@ -119,7 +119,7 @@ func TestTrieRandomIPv6(t *testing.T) {
 		slow = slow.Insert(addr[:], cidr, peers[index])
 	}
 
-	for n := 0; n < NumberOfTests; n += 1 {
+	for n := 0; n < NumberOfTests; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		peer1 := slow.Lookup(addr[:])

device/allowedips_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -20,26 +20,6 @@ type testPairCommonBits struct {
 	match uint
 }
 
-type testPairTrieInsert struct {
-	key  []byte
-	cidr uint
-	peer *Peer
-}
-
-type testPairTrieLookup struct {
-	key  []byte
-	peer *Peer
-}
-
-func printTrie(t *testing.T, p *trieEntry) {
-	if p == nil {
-		return
-	}
-	t.Log(p)
-	printTrie(t, p.child[0])
-	printTrie(t, p.child[1])
-}
-
 func TestCommonBits(t *testing.T) {
 
 	tests := []testPairCommonBits{
@@ -70,11 +50,11 @@ func benchmarkTrie(peerNumber int, addressNumber int, addressLength int, b *test
 
 	const AddressLength = 4
 
-	for n := 0; n < peerNumber; n += 1 {
+	for n := 0; n < peerNumber; n++ {
 		peers = append(peers, &Peer{})
 	}
 
-	for n := 0; n < addressNumber; n += 1 {
+	for n := 0; n < addressNumber; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		cidr := uint(rand.Uint32() % (AddressLength * 8))
@@ -82,7 +62,7 @@ func benchmarkTrie(peerNumber int, addressNumber int, addressLength int, b *test
 		trie = trie.insert(addr[:], cidr, peers[index])
 	}
 
-	for n := 0; n < b.N; n += 1 {
+	for n := 0; n < b.N; n++ {
 		var addr [AddressLength]byte
 		rand.Read(addr[:])
 		trie.lookup(addr[:])

device/bind_test.go

@@ -1,23 +1,24 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
-import "errors"
+import (
+	"errors"
+
+	"golang.zx2c4.com/wireguard/conn"
+)
 
 type DummyDatagram struct {
 	msg      []byte
-	endpoint Endpoint
-	world    bool // better type
+	endpoint conn.Endpoint
 }
 
 type DummyBind struct {
 	in6    chan DummyDatagram
-	ou6    chan DummyDatagram
 	in4    chan DummyDatagram
-	ou4    chan DummyDatagram
 	closed bool
 }
 
@@ -25,7 +26,7 @@ func (b *DummyBind) SetMark(v uint32) error {
 	return nil
 }
 
-func (b *DummyBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
+func (b *DummyBind) ReceiveIPv6(buff []byte) (int, conn.Endpoint, error) {
 	datagram, ok := <-b.in6
 	if !ok {
 		return 0, nil, errors.New("closed")
@@ -34,7 +35,7 @@ func (b *DummyBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
 	return len(datagram.msg), datagram.endpoint, nil
 }
 
-func (b *DummyBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
+func (b *DummyBind) ReceiveIPv4(buff []byte) (int, conn.Endpoint, error) {
 	datagram, ok := <-b.in4
 	if !ok {
 		return 0, nil, errors.New("closed")
@@ -50,6 +51,6 @@ func (b *DummyBind) Close() error {
 	return nil
 }
 
-func (b *DummyBind) Send(buff []byte, end Endpoint) error {
+func (b *DummyBind) Send(buff []byte, end conn.Endpoint) error {
 	return nil
 }

device/boundif_android.go

@@ -1,44 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
- */
-
-package device
-
-import "errors"
-
-func (device *Device) PeekLookAtSocketFd4() (fd int, err error) {
-	nb, ok := device.net.bind.(*nativeBind)
-	if !ok {
-		return 0, errors.New("no socket exists")
-	}
-	sysconn, err := nb.ipv4.SyscallConn()
-	if err != nil {
-		return
-	}
-	err = sysconn.Control(func(f uintptr) {
-		fd = int(f)
-	})
-	if err != nil {
-		return
-	}
-	return
-}
-
-func (device *Device) PeekLookAtSocketFd6() (fd int, err error) {
-	nb, ok := device.net.bind.(*nativeBind)
-	if !ok {
-		return 0, errors.New("no socket exists")
-	}
-	sysconn, err := nb.ipv6.SyscallConn()
-	if err != nil {
-		return
-	}
-	err = sysconn.Control(func(f uintptr) {
-		fd = int(f)
-	})
-	if err != nil {
-		return
-	}
-	return
-}

device/channels.go

@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"runtime"
+	"sync"
+)
+
+// An outboundQueue is a channel of QueueOutboundElements awaiting encryption.
+// An outboundQueue is ref-counted using its wg field.
+// An outboundQueue created with newOutboundQueue has one reference.
+// Every additional writer must call wg.Add(1).
+// Every completed writer must call wg.Done().
+// When no further writers will be added,
+// call wg.Done to remove the initial reference.
+// When the refcount hits 0, the queue's channel is closed.
+type outboundQueue struct {
+	c  chan *QueueOutboundElement
+	wg sync.WaitGroup
+}
+
+func newOutboundQueue() *outboundQueue {
+	q := &outboundQueue{
+		c: make(chan *QueueOutboundElement, QueueOutboundSize),
+	}
+	q.wg.Add(1)
+	go func() {
+		q.wg.Wait()
+		close(q.c)
+	}()
+	return q
+}
+
+// A inboundQueue is similar to an outboundQueue; see those docs.
+type inboundQueue struct {
+	c  chan *QueueInboundElement
+	wg sync.WaitGroup
+}
+
+func newInboundQueue() *inboundQueue {
+	q := &inboundQueue{
+		c: make(chan *QueueInboundElement, QueueInboundSize),
+	}
+	q.wg.Add(1)
+	go func() {
+		q.wg.Wait()
+		close(q.c)
+	}()
+	return q
+}
+
+// A handshakeQueue is similar to an outboundQueue; see those docs.
+type handshakeQueue struct {
+	c  chan QueueHandshakeElement
+	wg sync.WaitGroup
+}
+
+func newHandshakeQueue() *handshakeQueue {
+	q := &handshakeQueue{
+		c: make(chan QueueHandshakeElement, QueueHandshakeSize),
+	}
+	q.wg.Add(1)
+	go func() {
+		q.wg.Wait()
+		close(q.c)
+	}()
+	return q
+}
+
+type autodrainingInboundQueue struct {
+	c chan *QueueInboundElement
+}
+
+// newAutodrainingInboundQueue returns a channel that will be drained when it gets GC'd.
+// It is useful in cases in which is it hard to manage the lifetime of the channel.
+// The returned channel must not be closed. Senders should signal shutdown using
+// some other means, such as sending a sentinel nil values.
+func newAutodrainingInboundQueue(device *Device) *autodrainingInboundQueue {
+	q := &autodrainingInboundQueue{
+		c: make(chan *QueueInboundElement, QueueInboundSize),
+	}
+	runtime.SetFinalizer(q, device.flushInboundQueue)
+	return q
+}
+
+func (device *Device) flushInboundQueue(q *autodrainingInboundQueue) {
+	for {
+		select {
+		case elem := <-q.c:
+			elem.Lock()
+			device.PutMessageBuffer(elem.buffer)
+			device.PutInboundElement(elem)
+		default:
+			return
+		}
+	}
+}
+
+type autodrainingOutboundQueue struct {
+	c chan *QueueOutboundElement
+}
+
+// newAutodrainingOutboundQueue returns a channel that will be drained when it gets GC'd.
+// It is useful in cases in which is it hard to manage the lifetime of the channel.
+// The returned channel must not be closed. Senders should signal shutdown using
+// some other means, such as sending a sentinel nil values.
+// All sends to the channel must be best-effort, because there may be no receivers.
+func newAutodrainingOutboundQueue(device *Device) *autodrainingOutboundQueue {
+	q := &autodrainingOutboundQueue{
+		c: make(chan *QueueOutboundElement, QueueOutboundSize),
+	}
+	runtime.SetFinalizer(q, device.flushOutboundQueue)
+	return q
+}
+
+func (device *Device) flushOutboundQueue(q *autodrainingOutboundQueue) {
+	for {
+		select {
+		case elem := <-q.c:
+			elem.Lock()
+			device.PutMessageBuffer(elem.buffer)
+			device.PutOutboundElement(elem)
+		default:
+			return
+		}
+	}
+}

device/conn.go

@@ -1,187 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
- */
-
-package device
-
-import (
-	"errors"
-	"net"
-	"strings"
-
-	"golang.org/x/net/ipv4"
-	"golang.org/x/net/ipv6"
-)
-
-const (
-	ConnRoutineNumber = 2
-)
-
-/* A Bind handles listening on a port for both IPv6 and IPv4 UDP traffic
- */
-type Bind interface {
-	SetMark(value uint32) error
-	ReceiveIPv6(buff []byte) (int, Endpoint, error)
-	ReceiveIPv4(buff []byte) (int, Endpoint, error)
-	Send(buff []byte, end Endpoint) error
-	Close() error
-}
-
-/* An Endpoint maintains the source/destination caching for a peer
- *
- * dst : the remote address of a peer ("endpoint" in uapi terminology)
- * src : the local address from which datagrams originate going to the peer
- */
-type Endpoint interface {
-	ClearSrc()           // clears the source address
-	SrcToString() string // returns the local source address (ip:port)
-	DstToString() string // returns the destination address (ip:port)
-	DstToBytes() []byte  // used for mac2 cookie calculations
-	DstIP() net.IP
-	SrcIP() net.IP
-}
-
-func parseEndpoint(s string) (*net.UDPAddr, error) {
-	// ensure that the host is an IP address
-
-	host, _, err := net.SplitHostPort(s)
-	if err != nil {
-		return nil, err
-	}
-	if i := strings.LastIndexByte(host, '%'); i > 0 && strings.IndexByte(host, ':') >= 0 {
-		// Remove the scope, if any. ResolveUDPAddr below will use it, but here we're just
-		// trying to make sure with a small sanity test that this is a real IP address and
-		// not something that's likely to incur DNS lookups.
-		host = host[:i]
-	}
-	if ip := net.ParseIP(host); ip == nil {
-		return nil, errors.New("Failed to parse IP address: " + host)
-	}
-
-	// parse address and port
-
-	addr, err := net.ResolveUDPAddr("udp", s)
-	if err != nil {
-		return nil, err
-	}
-	ip4 := addr.IP.To4()
-	if ip4 != nil {
-		addr.IP = ip4
-	}
-	return addr, err
-}
-
-func unsafeCloseBind(device *Device) error {
-	var err error
-	netc := &device.net
-	if netc.bind != nil {
-		err = netc.bind.Close()
-		netc.bind = nil
-	}
-	netc.stopping.Wait()
-	return err
-}
-
-func (device *Device) BindSetMark(mark uint32) error {
-
-	device.net.Lock()
-	defer device.net.Unlock()
-
-	// check if modified
-
-	if device.net.fwmark == mark {
-		return nil
-	}
-
-	// update fwmark on existing bind
-
-	device.net.fwmark = mark
-	if device.isUp.Get() && device.net.bind != nil {
-		if err := device.net.bind.SetMark(mark); err != nil {
-			return err
-		}
-	}
-
-	// clear cached source addresses
-
-	device.peers.RLock()
-	for _, peer := range device.peers.keyMap {
-		peer.Lock()
-		defer peer.Unlock()
-		if peer.endpoint != nil {
-			peer.endpoint.ClearSrc()
-		}
-	}
-	device.peers.RUnlock()
-
-	return nil
-}
-
-func (device *Device) BindUpdate() error {
-
-	device.net.Lock()
-	defer device.net.Unlock()
-
-	// close existing sockets
-
-	if err := unsafeCloseBind(device); err != nil {
-		return err
-	}
-
-	// open new sockets
-
-	if device.isUp.Get() {
-
-		// bind to new port
-
-		var err error
-		netc := &device.net
-		netc.bind, netc.port, err = CreateBind(netc.port, device)
-		if err != nil {
-			netc.bind = nil
-			netc.port = 0
-			return err
-		}
-
-		// set fwmark
-
-		if netc.fwmark != 0 {
-			err = netc.bind.SetMark(netc.fwmark)
-			if err != nil {
-				return err
-			}
-		}
-
-		// clear cached source addresses
-
-		device.peers.RLock()
-		for _, peer := range device.peers.keyMap {
-			peer.Lock()
-			defer peer.Unlock()
-			if peer.endpoint != nil {
-				peer.endpoint.ClearSrc()
-			}
-		}
-		device.peers.RUnlock()
-
-		// start receiving routines
-
-		device.net.starting.Add(ConnRoutineNumber)
-		device.net.stopping.Add(ConnRoutineNumber)
-		go device.RoutineReceiveIncoming(ipv4.Version, netc.bind)
-		go device.RoutineReceiveIncoming(ipv6.Version, netc.bind)
-		device.net.starting.Wait()
-
-		device.log.Debug.Println("UDP bind has been updated")
-	}
-
-	return nil
-}
-
-func (device *Device) BindClose() error {
-	device.net.Lock()
-	err := unsafeCloseBind(device)
-	device.net.Unlock()
-	return err
-}

device/constants.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -13,7 +13,7 @@ import (
 
 const (
 	RekeyAfterMessages      = (1 << 60)
-	RejectAfterMessages     = (1 << 64) - (1 << 4) - 1
+	RejectAfterMessages     = (1 << 64) - (1 << 13) - 1
 	RekeyAfterTime          = time.Second * 120
 	RekeyAttemptTime        = time.Second * 90
 	RekeyTimeout            = time.Second * 5

device/cookie.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/cookie_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/device.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -11,35 +11,40 @@ import (
 	"sync/atomic"
 	"time"
 
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+
+	"golang.zx2c4.com/wireguard/conn"
 	"golang.zx2c4.com/wireguard/ratelimiter"
+	"golang.zx2c4.com/wireguard/rwcancel"
 	"golang.zx2c4.com/wireguard/tun"
 )
 
-const (
-	DeviceRoutineNumberPerCPU     = 3
-	DeviceRoutineNumberAdditional = 2
-)
-
 type Device struct {
-	isUp     AtomicBool // device is (going) up
-	isClosed AtomicBool // device is closed? (acting as guard)
-	log      *Logger
-
-	// synchronized resources (locks acquired in order)
-
 	state struct {
-		starting sync.WaitGroup
+		// state holds the device's state. It is accessed atomically.
+		// Use the device.deviceState method to read it.
+		// device.deviceState does not acquire the mutex, so it captures only a snapshot.
+		// During state transitions, the state variable is updated before the device itself.
+		// The state is thus either the current state of the device or
+		// the intended future state of the device.
+		// For example, while executing a call to Up, state will be deviceStateUp.
+		// There is no guarantee that that intended future state of the device
+		// will become the actual state; Up can fail.
+		// The device can also change state multiple times between time of check and time of use.
+		// Unsynchronized uses of state must therefore be advisory/best-effort only.
+		state uint32 // actually a deviceState, but typed uint32 for convenience
+		// stopping blocks until all inputs to Device have been closed.
 		stopping sync.WaitGroup
+		// mu protects state changes.
 		sync.Mutex
-		changing AtomicBool
-		current  bool
 	}
 
 	net struct {
-		starting sync.WaitGroup
 		stopping sync.WaitGroup
 		sync.RWMutex
-		bind   Bind   // bind interface
+		bind          conn.Bind // bind interface
+		netlinkCancel *rwcancel.RWCancel
 		port          uint16 // listening port
 		fwmark        uint32 // mark value (0 = disabled)
 	}
@@ -51,153 +56,172 @@ type Device struct {
 	}
 
 	peers struct {
-		sync.RWMutex
+		empty        AtomicBool // empty reports whether len(keyMap) == 0
+		sync.RWMutex            // protects keyMap
 		keyMap       map[NoisePublicKey]*Peer
 	}
 
-	// unprotected / "self-synchronising resources"
-
 	allowedips    AllowedIPs
 	indexTable    IndexTable
 	cookieChecker CookieChecker
 
 	rate struct {
-		underLoadUntil atomic.Value
+		underLoadUntil int64
 		limiter        ratelimiter.Ratelimiter
 	}
 
 	pool struct {
-		messageBufferPool        *sync.Pool
-		messageBufferReuseChan   chan *[MaxMessageSize]byte
-		inboundElementPool       *sync.Pool
-		inboundElementReuseChan  chan *QueueInboundElement
-		outboundElementPool      *sync.Pool
-		outboundElementReuseChan chan *QueueOutboundElement
+		messageBuffers   *WaitPool
+		inboundElements  *WaitPool
+		outboundElements *WaitPool
 	}
 
 	queue struct {
-		encryption chan *QueueOutboundElement
-		decryption chan *QueueInboundElement
-		handshake  chan QueueHandshakeElement
-	}
-
-	signals struct {
-		stop chan struct{}
+		encryption *outboundQueue
+		decryption *inboundQueue
+		handshake  *handshakeQueue
 	}
 
 	tun struct {
 		device tun.Device
 		mtu    int32
 	}
+
+	ipcMutex sync.RWMutex
+	closed   chan struct{}
+	log      *Logger
 }
 
-/* Converts the peer into a "zombie", which remains in the peer map,
- * but processes no packets and does not exists in the routing table.
- *
- * Must hold device.peers.Mutex
- */
-func unsafeRemovePeer(device *Device, peer *Peer, key NoisePublicKey) {
+// deviceState represents the state of a Device.
+// There are three states: down, up, closed.
+// Transitions:
+//
+//   down -----+
+//     ↑↓      ↓
+//     up -> closed
+//
+type deviceState uint32
 
+//go:generate go run golang.org/x/tools/cmd/stringer -type deviceState -trimprefix=deviceState
+const (
+	deviceStateDown deviceState = iota
+	deviceStateUp
+	deviceStateClosed
+)
+
+// deviceState returns device.state.state as a deviceState
+// See those docs for how to interpret this value.
+func (device *Device) deviceState() deviceState {
+	return deviceState(atomic.LoadUint32(&device.state.state))
+}
+
+// isClosed reports whether the device is closed (or is closing).
+// See device.state.state comments for how to interpret this value.
+func (device *Device) isClosed() bool {
+	return device.deviceState() == deviceStateClosed
+}
+
+// isUp reports whether the device is up (or is attempting to come up).
+// See device.state.state comments for how to interpret this value.
+func (device *Device) isUp() bool {
+	return device.deviceState() == deviceStateUp
+}
+
+// Must hold device.peers.Lock()
+func removePeerLocked(device *Device, peer *Peer, key NoisePublicKey) {
 	// stop routing and processing of packets
-
 	device.allowedips.RemoveByPeer(peer)
 	peer.Stop()
 
 	// remove from peer map
-
 	delete(device.peers.keyMap, key)
+	device.peers.empty.Set(len(device.peers.keyMap) == 0)
 }
 
-func deviceUpdateState(device *Device) {
-
-	// check if state already being updated (guard)
-
-	if device.state.changing.Swap(true) {
-		return
-	}
-
-	// compare to current state of device
-
+// changeState attempts to change the device state to match want.
+func (device *Device) changeState(want deviceState) (err error) {
 	device.state.Lock()
-
-	newIsUp := device.isUp.Get()
-
-	if newIsUp == device.state.current {
-		device.state.changing.Set(false)
-		device.state.Unlock()
-		return
+	defer device.state.Unlock()
+	old := device.deviceState()
+	if old == deviceStateClosed {
+		// once closed, always closed
+		device.log.Verbosef("Interface closed, ignored requested state %s", want)
+		return nil
 	}
-
-	// change state of device
-
-	switch newIsUp {
-	case true:
-		if err := device.BindUpdate(); err != nil {
-			device.log.Error.Printf("Unable to update bind: %v\n", err)
-			device.isUp.Set(false)
+	switch want {
+	case old:
+		return nil
+	case deviceStateUp:
+		atomic.StoreUint32(&device.state.state, uint32(deviceStateUp))
+		err = device.upLocked()
+		if err == nil {
 			break
 		}
+		fallthrough // up failed; bring the device all the way back down
+	case deviceStateDown:
+		atomic.StoreUint32(&device.state.state, uint32(deviceStateDown))
+		errDown := device.downLocked()
+		if err == nil {
+			err = errDown
+		}
+	}
+	device.log.Verbosef("Interface state was %s, requested %s, now %s", old, want, device.deviceState())
+	return
+}
+
+// upLocked attempts to bring the device up and reports whether it succeeded.
+// The caller must hold device.state.mu and is responsible for updating device.state.state.
+func (device *Device) upLocked() error {
+	if err := device.BindUpdate(); err != nil {
+		device.log.Errorf("Unable to update bind: %v", err)
+		return err
+	}
+
 	device.peers.RLock()
 	for _, peer := range device.peers.keyMap {
 		peer.Start()
-			if peer.persistentKeepaliveInterval > 0 {
+		if atomic.LoadUint32(&peer.persistentKeepaliveInterval) > 0 {
 			peer.SendKeepalive()
 		}
 	}
 	device.peers.RUnlock()
+	return nil
+}
+
+// downLocked attempts to bring the device down.
+// The caller must hold device.state.mu and is responsible for updating device.state.state.
+func (device *Device) downLocked() error {
+	err := device.BindClose()
+	if err != nil {
+		device.log.Errorf("Bind close failed: %v", err)
+	}
 
-	case false:
-		device.BindClose()
 	device.peers.RLock()
 	for _, peer := range device.peers.keyMap {
 		peer.Stop()
 	}
 	device.peers.RUnlock()
-	}
-
-	// update state variables
-
-	device.state.current = newIsUp
-	device.state.changing.Set(false)
-	device.state.Unlock()
-
-	// check for state change in the mean time
-
-	deviceUpdateState(device)
+	return err
 }
 
-func (device *Device) Up() {
-
-	// closed device cannot be brought up
-
-	if device.isClosed.Get() {
-		return
-	}
-
-	device.isUp.Set(true)
-	deviceUpdateState(device)
+func (device *Device) Up() error {
+	return device.changeState(deviceStateUp)
 }
 
-func (device *Device) Down() {
-	device.isUp.Set(false)
-	deviceUpdateState(device)
+func (device *Device) Down() error {
+	return device.changeState(deviceStateDown)
 }
 
 func (device *Device) IsUnderLoad() bool {
-
 	// check if currently under load
-
 	now := time.Now()
-	underLoad := len(device.queue.handshake) >= UnderLoadQueueSize
+	underLoad := len(device.queue.handshake.c) >= UnderLoadQueueSize
 	if underLoad {
-		device.rate.underLoadUntil.Store(now.Add(UnderLoadAfterTime))
+		atomic.StoreInt64(&device.rate.underLoadUntil, now.Add(UnderLoadAfterTime).UnixNano())
 		return true
 	}
-
 	// check if recently under load
-
-	until := device.rate.underLoadUntil.Load().(time.Time)
-	return until.After(now)
+	return atomic.LoadInt64(&device.rate.underLoadUntil) > now.UnixNano()
 }
 
 func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
@@ -224,7 +248,9 @@ func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
 	publicKey := sk.publicKey()
 	for key, peer := range device.peers.keyMap {
 		if peer.handshake.remoteStatic.Equals(publicKey) {
-			unsafeRemovePeer(device, peer, key)
+			peer.handshake.mutex.RUnlock()
+			removePeerLocked(device, peer, key)
+			peer.handshake.mutex.RLock()
 		}
 	}
 
@@ -236,24 +262,12 @@ func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
 
 	// do static-static DH pre-computations
 
-	rmKey := device.staticIdentity.privateKey.IsZero()
-
 	expiredPeers := make([]*Peer, 0, len(device.peers.keyMap))
-	for key, peer := range device.peers.keyMap {
+	for _, peer := range device.peers.keyMap {
 		handshake := &peer.handshake
-
-		if rmKey {
-			handshake.precomputedStaticStatic = [NoisePublicKeySize]byte{}
-		} else {
 		handshake.precomputedStaticStatic = device.staticIdentity.privateKey.sharedSecret(handshake.remoteStatic)
-		}
-
-		if isZero(handshake.precomputedStaticStatic[:]) {
-			unsafeRemovePeer(device, peer, key)
-		} else {
 		expiredPeers = append(expiredPeers, peer)
 	}
-	}
 
 	for _, peer := range lockedPeers {
 		peer.handshake.mutex.RUnlock()
@@ -267,39 +281,26 @@ func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
 
 func NewDevice(tunDevice tun.Device, logger *Logger) *Device {
 	device := new(Device)
-
-	device.isUp.Set(false)
-	device.isClosed.Set(false)
-
+	device.state.state = uint32(deviceStateDown)
+	device.closed = make(chan struct{})
 	device.log = logger
-
 	device.tun.device = tunDevice
 	mtu, err := device.tun.device.MTU()
 	if err != nil {
-		logger.Error.Println("Trouble determining MTU, assuming default:", err)
+		device.log.Errorf("Trouble determining MTU, assuming default: %v", err)
 		mtu = DefaultMTU
 	}
 	device.tun.mtu = int32(mtu)
-
 	device.peers.keyMap = make(map[NoisePublicKey]*Peer)
-
 	device.rate.limiter.Init()
-	device.rate.underLoadUntil.Store(time.Time{})
-
 	device.indexTable.Init()
-	device.allowedips.Reset()
-
 	device.PopulatePools()
 
 	// create queues
 
-	device.queue.handshake = make(chan QueueHandshakeElement, QueueHandshakeSize)
-	device.queue.encryption = make(chan *QueueOutboundElement, QueueOutboundSize)
-	device.queue.decryption = make(chan *QueueInboundElement, QueueInboundSize)
-
-	// prepare signals
-
-	device.signals.stop = make(chan struct{})
+	device.queue.handshake = newHandshakeQueue()
+	device.queue.encryption = newOutboundQueue()
+	device.queue.decryption = newInboundQueue()
 
 	// prepare net
 
@@ -309,21 +310,19 @@ func NewDevice(tunDevice tun.Device, logger *Logger) *Device {
 	// start workers
 
 	cpus := runtime.NumCPU()
-	device.state.starting.Wait()
 	device.state.stopping.Wait()
-	device.state.stopping.Add(DeviceRoutineNumberPerCPU*cpus + DeviceRoutineNumberAdditional)
-	device.state.starting.Add(DeviceRoutineNumberPerCPU*cpus + DeviceRoutineNumberAdditional)
-	for i := 0; i < cpus; i += 1 {
+	device.queue.encryption.wg.Add(cpus) // One for each RoutineHandshake
+	for i := 0; i < cpus; i++ {
 		go device.RoutineEncryption()
 		go device.RoutineDecryption()
 		go device.RoutineHandshake()
 	}
 
+	device.state.stopping.Add(1)      // RoutineReadFromTUN
+	device.queue.encryption.wg.Add(1) // RoutineReadFromTUN
 	go device.RoutineReadFromTUN()
 	go device.RoutineTUNEventReader()
 
-	device.state.starting.Wait()
-
 	return device
 }
 
@@ -341,7 +340,7 @@ func (device *Device) RemovePeer(key NoisePublicKey) {
 
 	peer, ok := device.peers.keyMap[key]
 	if ok {
-		unsafeRemovePeer(device, peer, key)
+		removePeerLocked(device, peer, key)
 	}
 }
 
@@ -350,67 +349,48 @@ func (device *Device) RemoveAllPeers() {
 	defer device.peers.Unlock()
 
 	for key, peer := range device.peers.keyMap {
-		unsafeRemovePeer(device, peer, key)
+		removePeerLocked(device, peer, key)
 	}
 
 	device.peers.keyMap = make(map[NoisePublicKey]*Peer)
 }
 
-func (device *Device) FlushPacketQueues() {
-	for {
-		select {
-		case elem, ok := <-device.queue.decryption:
-			if ok {
-				elem.Drop()
-			}
-		case elem, ok := <-device.queue.encryption:
-			if ok {
-				elem.Drop()
-			}
-		case <-device.queue.handshake:
-		default:
-			return
-		}
-	}
-
-}
-
 func (device *Device) Close() {
-	if device.isClosed.Swap(true) {
-		return
-	}
-
-	device.state.starting.Wait()
-
-	device.log.Info.Println("Device closing")
-	device.state.changing.Set(true)
 	device.state.Lock()
 	defer device.state.Unlock()
+	if device.isClosed() {
+		return
+	}
+	atomic.StoreUint32(&device.state.state, uint32(deviceStateClosed))
+	device.log.Verbosef("Device closing")
 
 	device.tun.device.Close()
-	device.BindClose()
-
-	device.isUp.Set(false)
-
-	close(device.signals.stop)
+	device.downLocked()
 
+	// Remove peers before closing queues,
+	// because peers assume that queues are active.
 	device.RemoveAllPeers()
 
+	// We kept a reference to the encryption and decryption queues,
+	// in case we started any new peers that might write to them.
+	// No new peers are coming; we are done with these queues.
+	device.queue.encryption.wg.Done()
+	device.queue.decryption.wg.Done()
+	device.queue.handshake.wg.Done()
 	device.state.stopping.Wait()
-	device.FlushPacketQueues()
 
 	device.rate.limiter.Close()
 
-	device.state.changing.Set(false)
-	device.log.Info.Println("Interface closed")
+	device.log.Verbosef("Device closed")
+	close(device.closed)
 }
 
 func (device *Device) Wait() chan struct{} {
-	return device.signals.stop
+	return device.closed
 }
 
 func (device *Device) SendKeepalivesToPeersWithCurrentKeypair() {
-	if device.isClosed.Get() {
+	if !device.isUp() {
 		return
 	}
 
@@ -425,3 +405,122 @@ func (device *Device) SendKeepalivesToPeersWithCurrentKeypair() {
 	}
 	device.peers.RUnlock()
 }
+
+func unsafeCloseBind(device *Device) error {
+	var err error
+	netc := &device.net
+	if netc.netlinkCancel != nil {
+		netc.netlinkCancel.Cancel()
+	}
+	if netc.bind != nil {
+		err = netc.bind.Close()
+		netc.bind = nil
+	}
+	netc.stopping.Wait()
+	return err
+}
+
+func (device *Device) Bind() conn.Bind {
+	device.net.Lock()
+	defer device.net.Unlock()
+	return device.net.bind
+}
+
+func (device *Device) BindSetMark(mark uint32) error {
+	device.net.Lock()
+	defer device.net.Unlock()
+
+	// check if modified
+	if device.net.fwmark == mark {
+		return nil
+	}
+
+	// update fwmark on existing bind
+	device.net.fwmark = mark
+	if device.isUp() && device.net.bind != nil {
+		if err := device.net.bind.SetMark(mark); err != nil {
+			return err
+		}
+	}
+
+	// clear cached source addresses
+	device.peers.RLock()
+	for _, peer := range device.peers.keyMap {
+		peer.Lock()
+		defer peer.Unlock()
+		if peer.endpoint != nil {
+			peer.endpoint.ClearSrc()
+		}
+	}
+	device.peers.RUnlock()
+
+	return nil
+}
+
+func (device *Device) BindUpdate() error {
+	device.net.Lock()
+	defer device.net.Unlock()
+
+	// close existing sockets
+	if err := unsafeCloseBind(device); err != nil {
+		return err
+	}
+
+	// open new sockets
+	if !device.isUp() {
+		return nil
+	}
+
+	// bind to new port
+	var err error
+	netc := &device.net
+	netc.bind, netc.port, err = conn.CreateBind(netc.port)
+	if err != nil {
+		netc.bind = nil
+		netc.port = 0
+		return err
+	}
+	netc.netlinkCancel, err = device.startRouteListener(netc.bind)
+	if err != nil {
+		netc.bind.Close()
+		netc.bind = nil
+		netc.port = 0
+		return err
+	}
+
+	// set fwmark
+	if netc.fwmark != 0 {
+		err = netc.bind.SetMark(netc.fwmark)
+		if err != nil {
+			return err
+		}
+	}
+
+	// clear cached source addresses
+	device.peers.RLock()
+	for _, peer := range device.peers.keyMap {
+		peer.Lock()
+		defer peer.Unlock()
+		if peer.endpoint != nil {
+			peer.endpoint.ClearSrc()
+		}
+	}
+	device.peers.RUnlock()
+
+	// start receiving routines
+	device.net.stopping.Add(2)
+	device.queue.decryption.wg.Add(2) // each RoutineReceiveIncoming goroutine writes to device.queue.decryption
+	device.queue.handshake.wg.Add(2)  // each RoutineReceiveIncoming goroutine writes to device.queue.handshake
+	go device.RoutineReceiveIncoming(ipv4.Version, netc.bind)
+	go device.RoutineReceiveIncoming(ipv6.Version, netc.bind)
+
+	device.log.Verbosef("UDP bind has been updated")
+	return nil
+}
+
+func (device *Device) BindClose() error {
+	device.net.Lock()
+	err := unsafeCloseBind(device)
+	device.net.Unlock()
+	return err
+}

device/device_test.go

@@ -1,216 +1,316 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
-	"bufio"
 	"bytes"
-	"encoding/binary"
-	"io"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"math/rand"
 	"net"
-	"os"
-	"strings"
+	"runtime"
+	"runtime/pprof"
+	"sync"
+	"sync/atomic"
+	"syscall"
 	"testing"
 	"time"
 
-	"golang.zx2c4.com/wireguard/tun"
+	"golang.zx2c4.com/wireguard/tun/tuntest"
 )
 
-func TestTwoDevicePing(t *testing.T) {
-	// TODO(crawshaw): pick unused ports on localhost
-	cfg1 := `private_key=481eb0d8113a4a5da532d2c3e9c14b53c8454b34ab109676f6b58c2245e37b58
-listen_port=53511
-replace_peers=true
-public_key=f70dbb6b1b92a1dde1c783b297016af3f572fef13b0abb16a2623d89a58e9725
-protocol_version=1
-replace_allowed_ips=true
-allowed_ip=1.0.0.2/32
-endpoint=127.0.0.1:53512`
-	tun1 := NewChannelTUN()
-	dev1 := NewDevice(tun1.TUN(), NewLogger(LogLevelDebug, "dev1: "))
-	dev1.Up()
-	defer dev1.Close()
-	if err := dev1.IpcSetOperation(bufio.NewReader(strings.NewReader(cfg1))); err != nil {
-		t.Fatal(err)
+// uapiCfg returns a string that contains cfg formatted use with IpcSet.
+// cfg is a series of alternating key/value strings.
+// uapiCfg exists because editors and humans like to insert
+// whitespace into configs, which can cause failures, some of which are silent.
+// For example, a leading blank newline causes the remainder
+// of the config to be silently ignored.
+func uapiCfg(cfg ...string) string {
+	if len(cfg)%2 != 0 {
+		panic("odd number of args to uapiReader")
 	}
-
-	cfg2 := `private_key=98c7989b1661a0d64fd6af3502000f87716b7c4bbcf00d04fc6073aa7b539768
-listen_port=53512
-replace_peers=true
-public_key=49e80929259cebdda4f322d6d2b1a6fad819d603acd26fd5d845e7a123036427
-protocol_version=1
-replace_allowed_ips=true
-allowed_ip=1.0.0.1/32
-endpoint=127.0.0.1:53511`
-	tun2 := NewChannelTUN()
-	dev2 := NewDevice(tun2.TUN(), NewLogger(LogLevelDebug, "dev2: "))
-	dev2.Up()
-	defer dev2.Close()
-	if err := dev2.IpcSetOperation(bufio.NewReader(strings.NewReader(cfg2))); err != nil {
-		t.Fatal(err)
+	buf := new(bytes.Buffer)
+	for i, s := range cfg {
+		buf.WriteString(s)
+		sep := byte('\n')
+		if i%2 == 0 {
+			sep = '='
 		}
-
-	t.Run("ping 1.0.0.1", func(t *testing.T) {
-		msg2to1 := ping(net.ParseIP("1.0.0.1"), net.ParseIP("1.0.0.2"))
-		tun2.Outbound <- msg2to1
-		select {
-		case msgRecv := <-tun1.Inbound:
-			if !bytes.Equal(msg2to1, msgRecv) {
-				t.Error("ping did not transit correctly")
+		buf.WriteByte(sep)
 	}
-		case <-time.After(300 * time.Millisecond):
-			t.Error("ping did not transit")
-		}
-	})
-
-	t.Run("ping 1.0.0.2", func(t *testing.T) {
-		msg1to2 := ping(net.ParseIP("1.0.0.2"), net.ParseIP("1.0.0.1"))
-		tun1.Outbound <- msg1to2
-		select {
-		case msgRecv := <-tun2.Inbound:
-			if !bytes.Equal(msg1to2, msgRecv) {
-				t.Error("return ping did not transit correctly")
-			}
-		case <-time.After(300 * time.Millisecond):
-			t.Error("return ping did not transit")
-		}
-	})
+	return buf.String()
 }
 
-func ping(dst, src net.IP) []byte {
-	localPort := uint16(1337)
-	seq := uint16(0)
-
-	payload := make([]byte, 4)
-	binary.BigEndian.PutUint16(payload[0:], localPort)
-	binary.BigEndian.PutUint16(payload[2:], seq)
-
-	return genICMPv4(payload, dst, src)
-}
-
-// checksum is the "internet checksum" from https://tools.ietf.org/html/rfc1071.
-func checksum(buf []byte, initial uint16) uint16 {
-	v := uint32(initial)
-	for i := 0; i < len(buf)-1; i += 2 {
-		v += uint32(binary.BigEndian.Uint16(buf[i:]))
+// genConfigs generates a pair of configs that connect to each other.
+// The configs use distinct, probably-usable ports.
+func genConfigs(tb testing.TB) (cfgs [2]string, endpointCfgs [2]string) {
+	var key1, key2 NoisePrivateKey
+	_, err := rand.Read(key1[:])
+	if err != nil {
+		tb.Errorf("unable to generate private key random bytes: %v", err)
 	}
-	if len(buf)%2 == 1 {
-		v += uint32(buf[len(buf)-1]) << 8
+	_, err = rand.Read(key2[:])
+	if err != nil {
+		tb.Errorf("unable to generate private key random bytes: %v", err)
 	}
-	for v > 0xffff {
-		v = (v >> 16) + (v & 0xffff)
-	}
-	return ^uint16(v)
-}
+	pub1, pub2 := key1.publicKey(), key2.publicKey()
 
-func genICMPv4(payload []byte, dst, src net.IP) []byte {
-	const (
-		icmpv4ProtocolNumber = 1
-		icmpv4Echo           = 8
-		icmpv4ChecksumOffset = 2
-		icmpv4Size           = 8
-		ipv4Size             = 20
-		ipv4TotalLenOffset   = 2
-		ipv4ChecksumOffset   = 10
-		ttl                  = 65
+	cfgs[0] = uapiCfg(
+		"private_key", hex.EncodeToString(key1[:]),
+		"listen_port", "0",
+		"replace_peers", "true",
+		"public_key", hex.EncodeToString(pub2[:]),
+		"protocol_version", "1",
+		"replace_allowed_ips", "true",
+		"allowed_ip", "1.0.0.2/32",
 	)
-
-	hdr := make([]byte, ipv4Size+icmpv4Size)
-
-	ip := hdr[0:ipv4Size]
-	icmpv4 := hdr[ipv4Size : ipv4Size+icmpv4Size]
-
-	// https://tools.ietf.org/html/rfc792
-	icmpv4[0] = icmpv4Echo // type
-	icmpv4[1] = 0          // code
-	chksum := ^checksum(icmpv4, checksum(payload, 0))
-	binary.BigEndian.PutUint16(icmpv4[icmpv4ChecksumOffset:], chksum)
-
-	// https://tools.ietf.org/html/rfc760 section 3.1
-	length := uint16(len(hdr) + len(payload))
-	ip[0] = (4 << 4) | (ipv4Size / 4)
-	binary.BigEndian.PutUint16(ip[ipv4TotalLenOffset:], length)
-	ip[8] = ttl
-	ip[9] = icmpv4ProtocolNumber
-	copy(ip[12:], src.To4())
-	copy(ip[16:], dst.To4())
-	chksum = ^checksum(ip[:], 0)
-	binary.BigEndian.PutUint16(ip[ipv4ChecksumOffset:], chksum)
-
-	var v []byte
-	v = append(v, hdr...)
-	v = append(v, payload...)
-	return []byte(v)
+	endpointCfgs[0] = uapiCfg(
+		"public_key", hex.EncodeToString(pub2[:]),
+		"endpoint", "127.0.0.1:%d",
+	)
+	cfgs[1] = uapiCfg(
+		"private_key", hex.EncodeToString(key2[:]),
+		"listen_port", "0",
+		"replace_peers", "true",
+		"public_key", hex.EncodeToString(pub1[:]),
+		"protocol_version", "1",
+		"replace_allowed_ips", "true",
+		"allowed_ip", "1.0.0.1/32",
+	)
+	endpointCfgs[1] = uapiCfg(
+		"public_key", hex.EncodeToString(pub1[:]),
+		"endpoint", "127.0.0.1:%d",
+	)
+	return
 }
 
-// TODO(crawshaw): find a reusable home for this. package devicetest?
-type ChannelTUN struct {
-	Inbound  chan []byte // incoming packets, closed on TUN close
-	Outbound chan []byte // outbound packets, blocks forever on TUN close
+// A testPair is a pair of testPeers.
+type testPair [2]testPeer
 
-	closed chan struct{}
-	events chan tun.Event
-	tun    chTun
+// A testPeer is a peer used for testing.
+type testPeer struct {
+	tun *tuntest.ChannelTUN
+	dev *Device
+	ip  net.IP
 }
 
-func NewChannelTUN() *ChannelTUN {
-	c := &ChannelTUN{
-		Inbound:  make(chan []byte),
-		Outbound: make(chan []byte),
-		closed:   make(chan struct{}),
-		events:   make(chan tun.Event, 1),
+type SendDirection bool
+
+const (
+	Ping SendDirection = true
+	Pong SendDirection = false
+)
+
+func (d SendDirection) String() string {
+	if d == Ping {
+		return "ping"
 	}
-	c.tun.c = c
-	c.events <- tun.EventUp
-	return c
+	return "pong"
 }
 
-func (c *ChannelTUN) TUN() tun.Device {
-	return &c.tun
-}
-
-type chTun struct {
-	c *ChannelTUN
-}
-
-func (t *chTun) File() *os.File { return nil }
-
-func (t *chTun) Read(data []byte, offset int) (int, error) {
+func (pair *testPair) Send(tb testing.TB, ping SendDirection, done chan struct{}) {
+	tb.Helper()
+	p0, p1 := pair[0], pair[1]
+	if !ping {
+		// pong is the new ping
+		p0, p1 = p1, p0
+	}
+	msg := tuntest.Ping(p0.ip, p1.ip)
+	p1.tun.Outbound <- msg
+	timer := time.NewTimer(5 * time.Second)
+	defer timer.Stop()
+	var err error
 	select {
-	case <-t.c.closed:
-		return 0, io.EOF // TODO(crawshaw): what is the correct error value?
-	case msg := <-t.c.Outbound:
-		return copy(data[offset:], msg), nil
+	case msgRecv := <-p0.tun.Inbound:
+		if !bytes.Equal(msg, msgRecv) {
+			err = fmt.Errorf("%s did not transit correctly", ping)
 		}
-}
-
-// Write is called by the wireguard device to deliver a packet for routing.
-func (t *chTun) Write(data []byte, offset int) (int, error) {
-	if offset == -1 {
-		close(t.c.closed)
-		close(t.c.events)
-		return 0, io.EOF
+	case <-timer.C:
+		err = fmt.Errorf("%s did not transit", ping)
+	case <-done:
 	}
-	msg := make([]byte, len(data)-offset)
-	copy(msg, data[offset:])
+	if err != nil {
+		// The error may have occurred because the test is done.
 		select {
-	case <-t.c.closed:
-		return 0, io.EOF // TODO(crawshaw): what is the correct error value?
-	case t.c.Inbound <- msg:
-		return len(data) - offset, nil
+		case <-done:
+			return
+		default:
+		}
+		// Real error.
+		tb.Error(err)
 	}
 }
 
-func (t *chTun) Flush() error           { return nil }
-func (t *chTun) MTU() (int, error)      { return DefaultMTU, nil }
-func (t *chTun) Name() (string, error)  { return "loopbackTun1", nil }
-func (t *chTun) Events() chan tun.Event { return t.c.events }
-func (t *chTun) Close() error {
-	t.Write(nil, -1)
-	return nil
+// genTestPair creates a testPair.
+func genTestPair(tb testing.TB) (pair testPair) {
+	cfg, endpointCfg := genConfigs(tb)
+	// Bring up a ChannelTun for each config.
+	for i := range pair {
+		p := &pair[i]
+		p.tun = tuntest.NewChannelTUN()
+		p.ip = net.IPv4(1, 0, 0, byte(i+1))
+		level := LogLevelVerbose
+		if _, ok := tb.(*testing.B); ok && !testing.Verbose() {
+			level = LogLevelError
+		}
+		p.dev = NewDevice(p.tun.TUN(), NewLogger(level, fmt.Sprintf("dev%d: ", i)))
+		if err := p.dev.IpcSet(cfg[i]); err != nil {
+			tb.Errorf("failed to configure device %d: %v", i, err)
+			p.dev.Close()
+			continue
+		}
+		if err := p.dev.Up(); err != nil {
+			tb.Errorf("failed to bring up device %d: %v", i, err)
+			p.dev.Close()
+			continue
+		}
+		endpointCfg[i^1] = fmt.Sprintf(endpointCfg[i^1], p.dev.net.port)
+	}
+	for i := range pair {
+		p := &pair[i]
+		if err := p.dev.IpcSet(endpointCfg[i]); err != nil {
+			tb.Errorf("failed to configure device endpoint %d: %v", i, err)
+			p.dev.Close()
+			continue
+		}
+		// The device is ready. Close it when the test completes.
+		tb.Cleanup(p.dev.Close)
+	}
+	return
+}
+
+func TestTwoDevicePing(t *testing.T) {
+	goroutineLeakCheck(t)
+	pair := genTestPair(t)
+	t.Run("ping 1.0.0.1", func(t *testing.T) {
+		pair.Send(t, Ping, nil)
+	})
+	t.Run("ping 1.0.0.2", func(t *testing.T) {
+		pair.Send(t, Pong, nil)
+	})
+}
+
+func TestUpDown(t *testing.T) {
+	goroutineLeakCheck(t)
+	const itrials = 20
+	const otrials = 1
+
+	for n := 0; n < otrials; n++ {
+		pair := genTestPair(t)
+		for i := range pair {
+			for k := range pair[i].dev.peers.keyMap {
+				pair[i].dev.IpcSet(fmt.Sprintf("public_key=%s\npersistent_keepalive_interval=1\n", hex.EncodeToString(k[:])))
+			}
+		}
+		var wg sync.WaitGroup
+		wg.Add(len(pair))
+		for i := range pair {
+			go func(d *Device) {
+				defer wg.Done()
+				for i := 0; i < itrials; i++ {
+					start := time.Now()
+					for {
+						if err := d.Up(); err != nil {
+							if errors.Is(err, syscall.EADDRINUSE) && time.Now().Sub(start) < time.Second*4 {
+								// Some other test process is racing with us, so try again.
+								time.Sleep(time.Millisecond * 10)
+								continue
+							}
+							t.Errorf("failed up bring up device: %v", err)
+						}
+						break
+					}
+					time.Sleep(time.Duration(rand.Intn(int(time.Nanosecond * (0x10000 - 1)))))
+					if err := d.Down(); err != nil {
+						t.Errorf("failed to bring down device: %v", err)
+					}
+					time.Sleep(time.Duration(rand.Intn(int(time.Nanosecond * (0x10000 - 1)))))
+				}
+			}(pair[i].dev)
+		}
+		wg.Wait()
+		for i := range pair {
+			pair[i].dev.Up()
+			pair[i].dev.Close()
+		}
+	}
+}
+
+// TestConcurrencySafety does other things concurrently with tunnel use.
+// It is intended to be used with the race detector to catch data races.
+func TestConcurrencySafety(t *testing.T) {
+	pair := genTestPair(t)
+	done := make(chan struct{})
+
+	const warmupIters = 10
+	var warmup sync.WaitGroup
+	warmup.Add(warmupIters)
+	go func() {
+		// Send data continuously back and forth until we're done.
+		// Note that we may continue to attempt to send data
+		// even after done is closed.
+		i := warmupIters
+		for ping := Ping; ; ping = !ping {
+			pair.Send(t, ping, done)
+			select {
+			case <-done:
+				return
+			default:
+			}
+			if i > 0 {
+				warmup.Done()
+				i--
+			}
+		}
+	}()
+	warmup.Wait()
+
+	applyCfg := func(cfg string) {
+		err := pair[0].dev.IpcSet(cfg)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	// Change persistent_keepalive_interval concurrently with tunnel use.
+	t.Run("persistentKeepaliveInterval", func(t *testing.T) {
+		var pub NoisePublicKey
+		for key := range pair[0].dev.peers.keyMap {
+			pub = key
+			break
+		}
+		cfg := uapiCfg(
+			"public_key", hex.EncodeToString(pub[:]),
+			"persistent_keepalive_interval", "1",
+		)
+		for i := 0; i < 1000; i++ {
+			applyCfg(cfg)
+		}
+	})
+
+	// Change private keys concurrently with tunnel use.
+	t.Run("privateKey", func(t *testing.T) {
+		bad := uapiCfg("private_key", "7777777777777777777777777777777777777777777777777777777777777777")
+		good := uapiCfg("private_key", hex.EncodeToString(pair[0].dev.staticIdentity.privateKey[:]))
+		// Set iters to a large number like 1000 to flush out data races quickly.
+		// Don't leave it large. That can cause logical races
+		// in which the handshake is interleaved with key changes
+		// such that the private key appears to be unchanging but
+		// other state gets reset, which can cause handshake failures like
+		// "Received packet with invalid mac1".
+		const iters = 1
+		for i := 0; i < iters; i++ {
+			applyCfg(bad)
+			applyCfg(good)
+		}
+	})
+
+	close(done)
 }
 
 func assertNil(t *testing.T, err error) {
@@ -236,3 +336,99 @@ func randDevice(t *testing.T) *Device {
 	device.SetPrivateKey(sk)
 	return device
 }
+
+func BenchmarkLatency(b *testing.B) {
+	pair := genTestPair(b)
+
+	// Establish a connection.
+	pair.Send(b, Ping, nil)
+	pair.Send(b, Pong, nil)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		pair.Send(b, Ping, nil)
+		pair.Send(b, Pong, nil)
+	}
+}
+
+func BenchmarkThroughput(b *testing.B) {
+	pair := genTestPair(b)
+
+	// Establish a connection.
+	pair.Send(b, Ping, nil)
+	pair.Send(b, Pong, nil)
+
+	// Measure how long it takes to receive b.N packets,
+	// starting when we receive the first packet.
+	var recv uint64
+	var elapsed time.Duration
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		var start time.Time
+		for {
+			<-pair[0].tun.Inbound
+			new := atomic.AddUint64(&recv, 1)
+			if new == 1 {
+				start = time.Now()
+			}
+			// Careful! Don't change this to else if; b.N can be equal to 1.
+			if new == uint64(b.N) {
+				elapsed = time.Since(start)
+				return
+			}
+		}
+	}()
+
+	// Send packets as fast as we can until we've received enough.
+	ping := tuntest.Ping(pair[0].ip, pair[1].ip)
+	pingc := pair[1].tun.Outbound
+	var sent uint64
+	for atomic.LoadUint64(&recv) != uint64(b.N) {
+		sent++
+		pingc <- ping
+	}
+	wg.Wait()
+
+	b.ReportMetric(float64(elapsed)/float64(b.N), "ns/op")
+	b.ReportMetric(1-float64(b.N)/float64(sent), "packet-loss")
+}
+
+func BenchmarkUAPIGet(b *testing.B) {
+	pair := genTestPair(b)
+	pair.Send(b, Ping, nil)
+	pair.Send(b, Pong, nil)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		pair[0].dev.IpcGetOperation(ioutil.Discard)
+	}
+}
+
+func goroutineLeakCheck(t *testing.T) {
+	goroutines := func() (int, []byte) {
+		p := pprof.Lookup("goroutine")
+		b := new(bytes.Buffer)
+		p.WriteTo(b, 1)
+		return p.Count(), b.Bytes()
+	}
+
+	startGoroutines, startStacks := goroutines()
+	t.Cleanup(func() {
+		if t.Failed() {
+			return
+		}
+		// Give goroutines time to exit, if they need it.
+		for i := 0; i < 10000; i++ {
+			if runtime.NumGoroutine() <= startGoroutines {
+				return
+			}
+			time.Sleep(1 * time.Millisecond)
+		}
+		endGoroutines, endStacks := goroutines()
+		t.Logf("starting stacks:\n%s\n", startStacks)
+		t.Logf("ending stacks:\n%s\n", endStacks)
+		t.Fatalf("expected %d goroutines, got %d, leak?", startGoroutines, endGoroutines)
+	})
+}

device/devicestate_string.go

@@ -0,0 +1,16 @@
+// Code generated by "stringer -type deviceState -trimprefix=deviceState"; DO NOT EDIT.
+
+package device
+
+import "strconv"
+
+const _deviceState_name = "DownUpClosed"
+
+var _deviceState_index = [...]uint8{0, 4, 6, 12}
+
+func (i deviceState) String() string {
+	if i >= deviceState(len(_deviceState_index)-1) {
+		return "deviceState(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _deviceState_name[_deviceState_index[i]:_deviceState_index[i+1]]
+}

device/endpoint_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/indextable.go

@@ -1,14 +1,14 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
 	"crypto/rand"
+	"encoding/binary"
 	"sync"
-	"unsafe"
 )
 
 type IndexTableEntry struct {
@@ -25,7 +25,8 @@ type IndexTable struct {
 func randUint32() (uint32, error) {
 	var integer [4]byte
 	_, err := rand.Read(integer[:])
-	return *(*uint32)(unsafe.Pointer(&integer[0])), err
+	// Arbitrary endianness; both are intrinsified by the Go compiler.
+	return binary.LittleEndian.Uint32(integer[:]), err
 }
 
 func (table *IndexTable) Init() {

device/ip.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/kdf_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/keypair.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -8,7 +8,9 @@ package device
 import (
 	"crypto/cipher"
 	"sync"
+	"sync/atomic"
 	"time"
+	"unsafe"
 
 	"golang.zx2c4.com/wireguard/replay"
 )
@@ -21,10 +23,10 @@ import (
  */
 
 type Keypair struct {
-	sendNonce    uint64
+	sendNonce    uint64 // accessed atomically
 	send         cipher.AEAD
 	receive      cipher.AEAD
-	replayFilter replay.ReplayFilter
+	replayFilter replay.Filter
 	isInitiator  bool
 	created      time.Time
 	localIndex   uint32
@@ -38,6 +40,14 @@ type Keypairs struct {
 	next     *Keypair
 }
 
+func (kp *Keypairs) storeNext(next *Keypair) {
+	atomic.StorePointer((*unsafe.Pointer)((unsafe.Pointer)(&kp.next)), (unsafe.Pointer)(next))
+}
+
+func (kp *Keypairs) loadNext() *Keypair {
+	return (*Keypair)(atomic.LoadPointer((*unsafe.Pointer)((unsafe.Pointer)(&kp.next))))
+}
+
 func (kp *Keypairs) Current() *Keypair {
 	kp.RLock()
 	defer kp.RUnlock()

device/logger.go

@@ -1,59 +1,48 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
-	"io"
-	"io/ioutil"
 	"log"
 	"os"
 )
 
+// A Logger provides logging for a Device.
+// The functions are Printf-style functions.
+// They must be safe for concurrent use.
+// They do not require a trailing newline in the format.
+// If nil, that level of logging will be silent.
+type Logger struct {
+	Verbosef func(format string, args ...interface{})
+	Errorf   func(format string, args ...interface{})
+}
+
+// Log levels for use with NewLogger.
 const (
 	LogLevelSilent = iota
 	LogLevelError
-	LogLevelInfo
-	LogLevelDebug
+	LogLevelVerbose
 )
 
-type Logger struct {
-	Debug *log.Logger
-	Info  *log.Logger
-	Error *log.Logger
-}
+// Function for use in Logger for discarding logged lines.
+func DiscardLogf(format string, args ...interface{}) {}
 
+// NewLogger constructs a Logger that writes to stdout.
+// It logs at the specified log level and above.
+// It decorates log lines with the log level, date, time, and prepend.
 func NewLogger(level int, prepend string) *Logger {
-	output := os.Stdout
-	logger := new(Logger)
-
-	logErr, logInfo, logDebug := func() (io.Writer, io.Writer, io.Writer) {
-		if level >= LogLevelDebug {
-			return output, output, output
+	logger := &Logger{DiscardLogf, DiscardLogf}
+	logf := func(prefix string) func(string, ...interface{}) {
+		return log.New(os.Stdout, prefix+": "+prepend, log.Ldate|log.Ltime).Printf
 	}
-		if level >= LogLevelInfo {
-			return output, output, ioutil.Discard
+	if level >= LogLevelVerbose {
+		logger.Verbosef = logf("DEBUG")
 	}
 	if level >= LogLevelError {
-			return output, ioutil.Discard, ioutil.Discard
+		logger.Errorf = logf("ERROR")
 	}
-		return ioutil.Discard, ioutil.Discard, ioutil.Discard
-	}()
-
-	logger.Debug = log.New(logDebug,
-		"DEBUG: "+prepend,
-		log.Ldate|log.Ltime,
-	)
-
-	logger.Info = log.New(logInfo,
-		"INFO: "+prepend,
-		log.Ldate|log.Ltime,
-	)
-	logger.Error = log.New(logErr,
-		"ERROR: "+prepend,
-		log.Ldate|log.Ltime,
-	)
 	return logger
 }

device/misc.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/mobilequirks.go

@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+func (device *Device) DisableSomeRoamingForBrokenMobileSemantics() {
+	device.peers.RLock()
+	for _, peer := range device.peers.keyMap {
+		peer.Lock()
+		defer peer.Unlock()
+		peer.disableRoaming = peer.endpoint != nil
+	}
+	device.peers.RUnlock()
+}

device/noise-helpers.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/noise-protocol.go

@@ -1,29 +1,51 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
 	"errors"
+	"fmt"
 	"sync"
 	"time"
 
 	"golang.org/x/crypto/blake2s"
 	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/crypto/poly1305"
+
 	"golang.zx2c4.com/wireguard/tai64n"
 )
 
+type handshakeState int
+
+// TODO(crawshaw): add commentary describing each state and the transitions
 const (
-	HandshakeZeroed = iota
-	HandshakeInitiationCreated
-	HandshakeInitiationConsumed
-	HandshakeResponseCreated
-	HandshakeResponseConsumed
+	handshakeZeroed = handshakeState(iota)
+	handshakeInitiationCreated
+	handshakeInitiationConsumed
+	handshakeResponseCreated
+	handshakeResponseConsumed
 )
 
+func (hs handshakeState) String() string {
+	switch hs {
+	case handshakeZeroed:
+		return "handshakeZeroed"
+	case handshakeInitiationCreated:
+		return "handshakeInitiationCreated"
+	case handshakeInitiationConsumed:
+		return "handshakeInitiationConsumed"
+	case handshakeResponseCreated:
+		return "handshakeResponseCreated"
+	case handshakeResponseConsumed:
+		return "handshakeResponseConsumed"
+	default:
+		return fmt.Sprintf("Handshake(UNKNOWN:%d)", int(hs))
+	}
+}
+
 const (
 	NoiseConstruction = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"
 	WGIdentifier      = "WireGuard v1 zx2c4 Jason@zx2c4.com"
@@ -95,11 +117,11 @@ type MessageCookieReply struct {
 }
 
 type Handshake struct {
-	state                     int
+	state                     handshakeState
 	mutex                     sync.RWMutex
 	hash                      [blake2s.Size]byte       // hash value
 	chainKey                  [blake2s.Size]byte       // chain key
-	presharedKey              NoiseSymmetricKey        // psk
+	presharedKey              NoisePresharedKey        // psk
 	localEphemeral            NoisePrivateKey          // ephemeral secret key
 	localIndex                uint32                   // used to clear hash-table
 	remoteIndex               uint32                   // index for sending
@@ -135,7 +157,7 @@ func (h *Handshake) Clear() {
 	setZero(h.chainKey[:])
 	setZero(h.hash[:])
 	h.localIndex = 0
-	h.state = HandshakeZeroed
+	h.state = handshakeZeroed
 }
 
 func (h *Handshake) mixHash(data []byte) {
@@ -154,6 +176,7 @@ func init() {
 }
 
 func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, error) {
+	var errZeroECDHResult = errors.New("ECDH returned all zeros")
 
 	device.staticIdentity.RLock()
 	defer device.staticIdentity.RUnlock()
@@ -162,12 +185,7 @@ func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, e
 	handshake.mutex.Lock()
 	defer handshake.mutex.Unlock()
 
-	if isZero(handshake.precomputedStaticStatic[:]) {
-		return nil, errors.New("static shared secret is zero")
-	}
-
 	// create ephemeral key
-
 	var err error
 	handshake.hash = InitialHash
 	handshake.chainKey = InitialChainKey
@@ -176,31 +194,22 @@ func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, e
 		return nil, err
 	}
 
-	// assign index
-
-	device.indexTable.Delete(handshake.localIndex)
-	handshake.localIndex, err = device.indexTable.NewIndexForHandshake(peer, handshake)
-
-	if err != nil {
-		return nil, err
-	}
-
 	handshake.mixHash(handshake.remoteStatic[:])
 
 	msg := MessageInitiation{
 		Type:      MessageInitiationType,
 		Ephemeral: handshake.localEphemeral.publicKey(),
-		Sender:    handshake.localIndex,
 	}
 
 	handshake.mixKey(msg.Ephemeral[:])
 	handshake.mixHash(msg.Ephemeral[:])
 
 	// encrypt static key
-
-	func() {
-		var key [chacha20poly1305.KeySize]byte
 	ss := handshake.localEphemeral.sharedSecret(handshake.remoteStatic)
+	if isZero(ss[:]) {
+		return nil, errZeroECDHResult
+	}
+	var key [chacha20poly1305.KeySize]byte
 	KDF2(
 		&handshake.chainKey,
 		&key,
@@ -209,26 +218,32 @@ func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, e
 	)
 	aead, _ := chacha20poly1305.New(key[:])
 	aead.Seal(msg.Static[:0], ZeroNonce[:], device.staticIdentity.publicKey[:], handshake.hash[:])
-	}()
 	handshake.mixHash(msg.Static[:])
 
 	// encrypt timestamp
-
-	timestamp := tai64n.Now()
-	func() {
-		var key [chacha20poly1305.KeySize]byte
+	if isZero(handshake.precomputedStaticStatic[:]) {
+		return nil, errZeroECDHResult
+	}
 	KDF2(
 		&handshake.chainKey,
 		&key,
 		handshake.chainKey[:],
 		handshake.precomputedStaticStatic[:],
 	)
-		aead, _ := chacha20poly1305.New(key[:])
+	timestamp := tai64n.Now()
+	aead, _ = chacha20poly1305.New(key[:])
 	aead.Seal(msg.Timestamp[:0], ZeroNonce[:], timestamp[:], handshake.hash[:])
-	}()
+
+	// assign index
+	device.indexTable.Delete(handshake.localIndex)
+	msg.Sender, err = device.indexTable.NewIndexForHandshake(peer, handshake)
+	if err != nil {
+		return nil, err
+	}
+	handshake.localIndex = msg.Sender
 
 	handshake.mixHash(msg.Timestamp[:])
-	handshake.state = HandshakeInitiationCreated
+	handshake.state = handshakeInitiationCreated
 	return &msg, nil
 }
 
@@ -250,16 +265,16 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
 	mixKey(&chainKey, &InitialChainKey, msg.Ephemeral[:])
 
 	// decrypt static key
-
 	var err error
 	var peerPK NoisePublicKey
-	func() {
 	var key [chacha20poly1305.KeySize]byte
 	ss := device.staticIdentity.privateKey.sharedSecret(msg.Ephemeral)
+	if isZero(ss[:]) {
+		return nil
+	}
 	KDF2(&chainKey, &key, chainKey[:], ss[:])
 	aead, _ := chacha20poly1305.New(key[:])
 	_, err = aead.Open(peerPK[:0], ZeroNonce[:], msg.Static[:], hash[:])
-	}()
 	if err != nil {
 		return nil
 	}
@@ -273,23 +288,24 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
 	}
 
 	handshake := &peer.handshake
-	if isZero(handshake.precomputedStaticStatic[:]) {
-		return nil
-	}
 
 	// verify identity
 
 	var timestamp tai64n.Timestamp
-	var key [chacha20poly1305.KeySize]byte
 
 	handshake.mutex.RLock()
+
+	if isZero(handshake.precomputedStaticStatic[:]) {
+		handshake.mutex.RUnlock()
+		return nil
+	}
 	KDF2(
 		&chainKey,
 		&key,
 		chainKey[:],
 		handshake.precomputedStaticStatic[:],
 	)
-	aead, _ := chacha20poly1305.New(key[:])
+	aead, _ = chacha20poly1305.New(key[:])
 	_, err = aead.Open(timestamp[:0], ZeroNonce[:], msg.Timestamp[:], hash[:])
 	if err != nil {
 		handshake.mutex.RUnlock()
@@ -299,11 +315,15 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
 
 	// protect against replay & flood
 
-	var ok bool
-	ok = timestamp.After(handshake.lastTimestamp)
-	ok = ok && time.Since(handshake.lastInitiationConsumption) > HandshakeInitationRate
+	replay := !timestamp.After(handshake.lastTimestamp)
+	flood := time.Since(handshake.lastInitiationConsumption) <= HandshakeInitationRate
 	handshake.mutex.RUnlock()
-	if !ok {
+	if replay {
+		device.log.Verbosef("%v - ConsumeMessageInitiation: handshake replay @ %v", peer, timestamp)
+		return nil
+	}
+	if flood {
+		device.log.Verbosef("%v - ConsumeMessageInitiation: handshake flood", peer)
 		return nil
 	}
 
@@ -322,7 +342,7 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
 	if now.After(handshake.lastInitiationConsumption) {
 		handshake.lastInitiationConsumption = now
 	}
-	handshake.state = HandshakeInitiationConsumed
+	handshake.state = handshakeInitiationConsumed
 
 	handshake.mutex.Unlock()
 
@@ -337,7 +357,7 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
 	handshake.mutex.Lock()
 	defer handshake.mutex.Unlock()
 
-	if handshake.state != HandshakeInitiationConsumed {
+	if handshake.state != handshakeInitiationConsumed {
 		return nil, errors.New("handshake initiation must be consumed first")
 	}
 
@@ -393,7 +413,7 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
 		handshake.mixHash(msg.Empty[:])
 	}()
 
-	handshake.state = HandshakeResponseCreated
+	handshake.state = handshakeResponseCreated
 
 	return &msg, nil
 }
@@ -423,7 +443,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
 		handshake.mutex.RLock()
 		defer handshake.mutex.RUnlock()
 
-		if handshake.state != HandshakeInitiationCreated {
+		if handshake.state != handshakeInitiationCreated {
 			return false
 		}
 
@@ -484,7 +504,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
 	handshake.hash = hash
 	handshake.chainKey = chainKey
 	handshake.remoteIndex = msg.Sender
-	handshake.state = HandshakeResponseConsumed
+	handshake.state = handshakeResponseConsumed
 
 	handshake.mutex.Unlock()
 
@@ -509,7 +529,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 	var sendKey [chacha20poly1305.KeySize]byte
 	var recvKey [chacha20poly1305.KeySize]byte
 
-	if handshake.state == HandshakeResponseConsumed {
+	if handshake.state == handshakeResponseConsumed {
 		KDF2(
 			&sendKey,
 			&recvKey,
@@ -517,7 +537,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 			nil,
 		)
 		isInitiator = true
-	} else if handshake.state == HandshakeResponseCreated {
+	} else if handshake.state == handshakeResponseCreated {
 		KDF2(
 			&recvKey,
 			&sendKey,
@@ -526,7 +546,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 		)
 		isInitiator = false
 	} else {
-		return errors.New("invalid state for keypair derivation")
+		return fmt.Errorf("invalid state for keypair derivation: %v", handshake.state)
 	}
 
 	// zero handshake
@@ -534,7 +554,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 	setZero(handshake.chainKey[:])
 	setZero(handshake.hash[:]) // Doesn't necessarily need to be zeroed. Could be used for something interesting down the line.
 	setZero(handshake.localEphemeral[:])
-	peer.handshake.state = HandshakeZeroed
+	peer.handshake.state = handshakeZeroed
 
 	// create AEAD instances
 
@@ -546,8 +566,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 	setZero(recvKey[:])
 
 	keypair.created = time.Now()
-	keypair.sendNonce = 0
-	keypair.replayFilter.Init()
+	keypair.replayFilter.Reset()
 	keypair.isInitiator = isInitiator
 	keypair.localIndex = peer.handshake.localIndex
 	keypair.remoteIndex = peer.handshake.remoteIndex
@@ -564,12 +583,12 @@ func (peer *Peer) BeginSymmetricSession() error {
 	defer keypairs.Unlock()
 
 	previous := keypairs.previous
-	next := keypairs.next
+	next := keypairs.loadNext()
 	current := keypairs.current
 
 	if isInitiator {
 		if next != nil {
-			keypairs.next = nil
+			keypairs.storeNext(nil)
 			keypairs.previous = next
 			device.DeleteKeypair(current)
 		} else {
@@ -578,7 +597,7 @@ func (peer *Peer) BeginSymmetricSession() error {
 		device.DeleteKeypair(previous)
 		keypairs.current = keypair
 	} else {
-		keypairs.next = keypair
+		keypairs.storeNext(keypair)
 		device.DeleteKeypair(next)
 		keypairs.previous = nil
 		device.DeleteKeypair(previous)
@@ -589,18 +608,19 @@ func (peer *Peer) BeginSymmetricSession() error {
 
 func (peer *Peer) ReceivedWithKeypair(receivedKeypair *Keypair) bool {
 	keypairs := &peer.keypairs
-	if keypairs.next != receivedKeypair {
+
+	if keypairs.loadNext() != receivedKeypair {
 		return false
 	}
 	keypairs.Lock()
 	defer keypairs.Unlock()
-	if keypairs.next != receivedKeypair {
+	if keypairs.loadNext() != receivedKeypair {
 		return false
 	}
 	old := keypairs.previous
 	keypairs.previous = keypairs.current
 	peer.device.DeleteKeypair(old)
-	keypairs.current = keypairs.next
-	keypairs.next = nil
+	keypairs.current = keypairs.loadNext()
+	keypairs.storeNext(nil)
 	return true
 }

device/noise-types.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -9,19 +9,18 @@ import (
 	"crypto/subtle"
 	"encoding/hex"
 	"errors"
-
-	"golang.org/x/crypto/chacha20poly1305"
 )
 
 const (
 	NoisePublicKeySize    = 32
 	NoisePrivateKeySize   = 32
+	NoisePresharedKeySize = 32
 )
 
 type (
 	NoisePublicKey    [NoisePublicKeySize]byte
 	NoisePrivateKey   [NoisePrivateKeySize]byte
-	NoiseSymmetricKey [chacha20poly1305.KeySize]byte
+	NoisePresharedKey [NoisePresharedKeySize]byte
 	NoiseNonce        uint64 // padded to 12-bytes
 )
 
@@ -52,18 +51,19 @@ func (key *NoisePrivateKey) FromHex(src string) (err error) {
 	return
 }
 
-func (key NoisePrivateKey) ToHex() string {
-	return hex.EncodeToString(key[:])
+func (key *NoisePrivateKey) FromMaybeZeroHex(src string) (err error) {
+	err = loadExactHex(key[:], src)
+	if key.IsZero() {
+		return
+	}
+	key.clamp()
+	return
 }
 
 func (key *NoisePublicKey) FromHex(src string) error {
 	return loadExactHex(key[:], src)
 }
 
-func (key NoisePublicKey) ToHex() string {
-	return hex.EncodeToString(key[:])
-}
-
 func (key NoisePublicKey) IsZero() bool {
 	var zero NoisePublicKey
 	return key.Equals(zero)
@@ -73,10 +73,6 @@ func (key NoisePublicKey) Equals(tar NoisePublicKey) bool {
 	return subtle.ConstantTimeCompare(key[:], tar[:]) == 1
 }
 
-func (key *NoiseSymmetricKey) FromHex(src string) error {
+func (key *NoisePresharedKey) FromHex(src string) error {
 	return loadExactHex(key[:], src)
 }
-
-func (key NoiseSymmetricKey) ToHex() string {
-	return hex.EncodeToString(key[:])
-}

device/noise_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -36,8 +36,14 @@ func TestNoiseHandshake(t *testing.T) {
 	defer dev1.Close()
 	defer dev2.Close()
 
-	peer1, _ := dev2.NewPeer(dev1.staticIdentity.privateKey.publicKey())
-	peer2, _ := dev1.NewPeer(dev2.staticIdentity.privateKey.publicKey())
+	peer1, err := dev2.NewPeer(dev1.staticIdentity.privateKey.publicKey())
+	if err != nil {
+		t.Fatal(err)
+	}
+	peer2, err := dev1.NewPeer(dev2.staticIdentity.privateKey.publicKey())
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	assertEqual(
 		t,
@@ -113,7 +119,7 @@ func TestNoiseHandshake(t *testing.T) {
 		t.Fatal("failed to derive keypair for peer 2", err)
 	}
 
-	key1 := peer1.keypairs.next
+	key1 := peer1.keypairs.loadNext()
 	key2 := peer2.keypairs.current
 
 	// encrypting / decryption test

device/peer.go

@@ -1,21 +1,20 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
+	"container/list"
 	"encoding/base64"
 	"errors"
 	"fmt"
 	"sync"
 	"sync/atomic"
 	"time"
-)
 
-const (
-	PeerRoutineNumber = 3
+	"golang.zx2c4.com/wireguard/conn"
 )
 
 type Peer struct {
@@ -24,16 +23,22 @@ type Peer struct {
 	keypairs     Keypairs
 	handshake    Handshake
 	device       *Device
-	endpoint                    Endpoint
-	persistentKeepaliveInterval uint16
+	endpoint     conn.Endpoint
+	stopping     sync.WaitGroup // routines pending stop
 
-	// This must be 64-bit aligned, so make sure the above members come out to even alignment and pad accordingly
+	// These fields are accessed with atomic operations, which must be
+	// 64-bit aligned even on 32-bit platforms. Go guarantees that an
+	// allocated struct will be 64-bit aligned. So we place
+	// atomically-accessed fields up front, so that they can share in
+	// this alignment before smaller fields throw it off.
 	stats struct {
 		txBytes           uint64 // bytes send to peer (endpoint)
 		rxBytes           uint64 // bytes received from peer
 		lastHandshakeNano int64  // nano seconds since epoch
 	}
 
+	disableRoaming bool
+
 	timers struct {
 		retransmitHandshake     *Timer
 		sendKeepalive           *Timer
@@ -45,35 +50,27 @@ type Peer struct {
 		sentLastMinuteHandshake AtomicBool
 	}
 
-	signals struct {
-		newKeypairArrived chan struct{}
-		flushNonceQueue   chan struct{}
+	state struct {
+		sync.Mutex // protects against concurrent Start/Stop
 	}
 
 	queue struct {
-		nonce                           chan *QueueOutboundElement // nonce / pre-handshake queue
-		outbound                        chan *QueueOutboundElement // sequential ordering of work
-		inbound                         chan *QueueInboundElement  // sequential ordering of work
-		packetInNonceQueueIsAwaitingKey AtomicBool
-	}
-
-	routines struct {
-		sync.Mutex                // held when stopping / starting routines
-		starting   sync.WaitGroup // routines pending start
-		stopping   sync.WaitGroup // routines pending stop
-		stop       chan struct{}  // size 0, stop all go routines in peer
+		staged   chan *QueueOutboundElement // staged packets before a handshake is available
+		outbound *autodrainingOutboundQueue // sequential ordering of udp transmission
+		inbound  *autodrainingInboundQueue  // sequential ordering of tun writing
 	}
 
 	cookieGenerator             CookieGenerator
+	trieEntries                 list.List
+	persistentKeepaliveInterval uint32 // accessed atomically
 }
 
 func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
-	if device.isClosed.Get() {
+	if device.isClosed() {
 		return nil, errors.New("device closed")
 	}
 
 	// lock resources
-
 	device.staticIdentity.RLock()
 	defer device.staticIdentity.RUnlock()
 
@@ -81,52 +78,44 @@ func (device *Device) NewPeer(pk NoisePublicKey) (*Peer, error) {
 	defer device.peers.Unlock()
 
 	// check if over limit
-
 	if len(device.peers.keyMap) >= MaxPeers {
 		return nil, errors.New("too many peers")
 	}
 
 	// create peer
-
 	peer := new(Peer)
 	peer.Lock()
 	defer peer.Unlock()
 
 	peer.cookieGenerator.Init(pk)
 	peer.device = device
-	peer.isRunning.Set(false)
+	peer.queue.outbound = newAutodrainingOutboundQueue(device)
+	peer.queue.inbound = newAutodrainingInboundQueue(device)
+	peer.queue.staged = make(chan *QueueOutboundElement, QueueStagedSize)
 
 	// map public key
-
 	_, ok := device.peers.keyMap[pk]
 	if ok {
 		return nil, errors.New("adding existing peer")
 	}
 
 	// pre-compute DH
-
 	handshake := &peer.handshake
 	handshake.mutex.Lock()
 	handshake.precomputedStaticStatic = device.staticIdentity.privateKey.sharedSecret(pk)
-	ssIsZero := isZero(handshake.precomputedStaticStatic[:])
 	handshake.remoteStatic = pk
 	handshake.mutex.Unlock()
 
 	// reset endpoint
-
 	peer.endpoint = nil
 
-	// conditionally add
-
-	if !ssIsZero {
+	// add
 	device.peers.keyMap[pk] = peer
-	} else {
-		return nil, nil
-	}
+	device.peers.empty.Set(false)
 
 	// start peer
-
-	if peer.device.isUp.Get() {
+	peer.timersInit()
+	if peer.device.isUp() {
 		peer.Start()
 	}
 
@@ -138,6 +127,11 @@ func (peer *Peer) SendBuffer(buffer []byte) error {
 	defer peer.device.net.RUnlock()
 
 	if peer.device.net.bind == nil {
+		// Packets can leak through to SendBuffer while the device is closing.
+		// When that happens, drop them silently to avoid spurious errors.
+		if peer.device.isClosed() {
+			return nil
+		}
 		return errors.New("no bind")
 	}
 
@@ -165,51 +159,39 @@ func (peer *Peer) String() string {
 }
 
 func (peer *Peer) Start() {
-
 	// should never start a peer on a closed device
-
-	if peer.device.isClosed.Get() {
+	if peer.device.isClosed() {
 		return
 	}
 
 	// prevent simultaneous start/stop operations
-
-	peer.routines.Lock()
-	defer peer.routines.Unlock()
+	peer.state.Lock()
+	defer peer.state.Unlock()
 
 	if peer.isRunning.Get() {
 		return
 	}
 
 	device := peer.device
-	device.log.Debug.Println(peer, "- Starting...")
+	device.log.Verbosef("%v - Starting...", peer)
 
 	// reset routine state
+	peer.stopping.Wait()
+	peer.stopping.Add(2)
 
-	peer.routines.starting.Wait()
-	peer.routines.stopping.Wait()
-	peer.routines.stop = make(chan struct{})
-	peer.routines.starting.Add(PeerRoutineNumber)
-	peer.routines.stopping.Add(PeerRoutineNumber)
-
-	// prepare queues
-
-	peer.queue.nonce = make(chan *QueueOutboundElement, QueueOutboundSize)
-	peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
-	peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
-
-	peer.timersInit()
+	peer.handshake.mutex.Lock()
 	peer.handshake.lastSentHandshake = time.Now().Add(-(RekeyTimeout + time.Second))
-	peer.signals.newKeypairArrived = make(chan struct{}, 1)
-	peer.signals.flushNonceQueue = make(chan struct{}, 1)
+	peer.handshake.mutex.Unlock()
 
-	// wait for routines to start
+	peer.device.queue.encryption.wg.Add(1) // keep encryption queue open for our writes
 
-	go peer.RoutineNonce()
+	peer.timersStart()
+
+	device.flushInboundQueue(peer.queue.inbound)
+	device.flushOutboundQueue(peer.queue.outbound)
 	go peer.RoutineSequentialSender()
 	go peer.RoutineSequentialReceiver()
 
-	peer.routines.starting.Wait()
 	peer.isRunning.Set(true)
 }
 
@@ -222,10 +204,10 @@ func (peer *Peer) ZeroAndFlushAll() {
 	keypairs.Lock()
 	device.DeleteKeypair(keypairs.previous)
 	device.DeleteKeypair(keypairs.current)
-	device.DeleteKeypair(keypairs.next)
+	device.DeleteKeypair(keypairs.loadNext())
 	keypairs.previous = nil
 	keypairs.current = nil
-	keypairs.next = nil
+	keypairs.storeNext(nil)
 	keypairs.Unlock()
 
 	// clear handshake state
@@ -236,7 +218,7 @@ func (peer *Peer) ZeroAndFlushAll() {
 	handshake.Clear()
 	handshake.mutex.Unlock()
 
-	peer.FlushNonceQueue()
+	peer.FlushStagedPackets()
 }
 
 func (peer *Peer) ExpireCurrentKeypairs() {
@@ -244,55 +226,43 @@ func (peer *Peer) ExpireCurrentKeypairs() {
 	handshake.mutex.Lock()
 	peer.device.indexTable.Delete(handshake.localIndex)
 	handshake.Clear()
-	handshake.mutex.Unlock()
 	peer.handshake.lastSentHandshake = time.Now().Add(-(RekeyTimeout + time.Second))
+	handshake.mutex.Unlock()
 
 	keypairs := &peer.keypairs
 	keypairs.Lock()
 	if keypairs.current != nil {
-		keypairs.current.sendNonce = RejectAfterMessages
+		atomic.StoreUint64(&keypairs.current.sendNonce, RejectAfterMessages)
 	}
 	if keypairs.next != nil {
-		keypairs.next.sendNonce = RejectAfterMessages
+		next := keypairs.loadNext()
+		atomic.StoreUint64(&next.sendNonce, RejectAfterMessages)
 	}
 	keypairs.Unlock()
 }
 
 func (peer *Peer) Stop() {
-
-	// prevent simultaneous start/stop operations
+	peer.state.Lock()
+	defer peer.state.Unlock()
 
 	if !peer.isRunning.Swap(false) {
 		return
 	}
 
-	peer.routines.starting.Wait()
-
-	peer.routines.Lock()
-	defer peer.routines.Unlock()
-
-	peer.device.log.Debug.Println(peer, "- Stopping...")
+	peer.device.log.Verbosef("%v - Stopping...", peer)
 
 	peer.timersStop()
-
-	// stop & wait for ongoing peer routines
-
-	close(peer.routines.stop)
-	peer.routines.stopping.Wait()
-
-	// close queues
-
-	close(peer.queue.nonce)
-	close(peer.queue.outbound)
-	close(peer.queue.inbound)
+	// Signal that RoutineSequentialSender and RoutineSequentialReceiver should exit.
+	peer.queue.inbound.c <- nil
+	peer.queue.outbound.c <- nil
+	peer.stopping.Wait()
+	peer.device.queue.encryption.wg.Done() // no more writes to encryption queue from us
 
 	peer.ZeroAndFlushAll()
 }
 
-var RoamingDisabled bool
-
-func (peer *Peer) SetEndpointFromPacket(endpoint Endpoint) {
-	if RoamingDisabled {
+func (peer *Peer) SetEndpointFromPacket(endpoint conn.Endpoint) {
+	if peer.disableRoaming {
 		return
 	}
 	peer.Lock()

device/pools.go

@@ -1,89 +1,84 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
-import "sync"
+import (
+	"sync"
+	"sync/atomic"
+)
+
+type WaitPool struct {
+	pool  sync.Pool
+	cond  sync.Cond
+	lock  sync.Mutex
+	count uint32
+	max   uint32
+}
+
+func NewWaitPool(max uint32, new func() interface{}) *WaitPool {
+	p := &WaitPool{pool: sync.Pool{New: new}, max: max}
+	p.cond = sync.Cond{L: &p.lock}
+	return p
+}
+
+func (p *WaitPool) Get() interface{} {
+	if p.max != 0 {
+		p.lock.Lock()
+		for atomic.LoadUint32(&p.count) >= p.max {
+			p.cond.Wait()
+		}
+		atomic.AddUint32(&p.count, 1)
+		p.lock.Unlock()
+	}
+	return p.pool.Get()
+}
+
+func (p *WaitPool) Put(x interface{}) {
+	p.pool.Put(x)
+	if p.max == 0 {
+		return
+	}
+	atomic.AddUint32(&p.count, ^uint32(0))
+	p.cond.Signal()
+}
 
 func (device *Device) PopulatePools() {
-	if PreallocatedBuffersPerPool == 0 {
-		device.pool.messageBufferPool = &sync.Pool{
-			New: func() interface{} {
+	device.pool.messageBuffers = NewWaitPool(PreallocatedBuffersPerPool, func() interface{} {
 		return new([MaxMessageSize]byte)
-			},
-		}
-		device.pool.inboundElementPool = &sync.Pool{
-			New: func() interface{} {
+	})
+	device.pool.inboundElements = NewWaitPool(PreallocatedBuffersPerPool, func() interface{} {
 		return new(QueueInboundElement)
-			},
-		}
-		device.pool.outboundElementPool = &sync.Pool{
-			New: func() interface{} {
+	})
+	device.pool.outboundElements = NewWaitPool(PreallocatedBuffersPerPool, func() interface{} {
 		return new(QueueOutboundElement)
-			},
-		}
-	} else {
-		device.pool.messageBufferReuseChan = make(chan *[MaxMessageSize]byte, PreallocatedBuffersPerPool)
-		for i := 0; i < PreallocatedBuffersPerPool; i += 1 {
-			device.pool.messageBufferReuseChan <- new([MaxMessageSize]byte)
-		}
-		device.pool.inboundElementReuseChan = make(chan *QueueInboundElement, PreallocatedBuffersPerPool)
-		for i := 0; i < PreallocatedBuffersPerPool; i += 1 {
-			device.pool.inboundElementReuseChan <- new(QueueInboundElement)
-		}
-		device.pool.outboundElementReuseChan = make(chan *QueueOutboundElement, PreallocatedBuffersPerPool)
-		for i := 0; i < PreallocatedBuffersPerPool; i += 1 {
-			device.pool.outboundElementReuseChan <- new(QueueOutboundElement)
-		}
-	}
+	})
 }
 
 func (device *Device) GetMessageBuffer() *[MaxMessageSize]byte {
-	if PreallocatedBuffersPerPool == 0 {
-		return device.pool.messageBufferPool.Get().(*[MaxMessageSize]byte)
-	} else {
-		return <-device.pool.messageBufferReuseChan
-	}
+	return device.pool.messageBuffers.Get().(*[MaxMessageSize]byte)
 }
 
 func (device *Device) PutMessageBuffer(msg *[MaxMessageSize]byte) {
-	if PreallocatedBuffersPerPool == 0 {
-		device.pool.messageBufferPool.Put(msg)
-	} else {
-		device.pool.messageBufferReuseChan <- msg
-	}
+	device.pool.messageBuffers.Put(msg)
 }
 
 func (device *Device) GetInboundElement() *QueueInboundElement {
-	if PreallocatedBuffersPerPool == 0 {
-		return device.pool.inboundElementPool.Get().(*QueueInboundElement)
-	} else {
-		return <-device.pool.inboundElementReuseChan
-	}
+	return device.pool.inboundElements.Get().(*QueueInboundElement)
 }
 
-func (device *Device) PutInboundElement(msg *QueueInboundElement) {
-	if PreallocatedBuffersPerPool == 0 {
-		device.pool.inboundElementPool.Put(msg)
-	} else {
-		device.pool.inboundElementReuseChan <- msg
-	}
+func (device *Device) PutInboundElement(elem *QueueInboundElement) {
+	elem.clearPointers()
+	device.pool.inboundElements.Put(elem)
 }
 
 func (device *Device) GetOutboundElement() *QueueOutboundElement {
-	if PreallocatedBuffersPerPool == 0 {
-		return device.pool.outboundElementPool.Get().(*QueueOutboundElement)
-	} else {
-		return <-device.pool.outboundElementReuseChan
-	}
+	return device.pool.outboundElements.Get().(*QueueOutboundElement)
 }
 
-func (device *Device) PutOutboundElement(msg *QueueOutboundElement) {
-	if PreallocatedBuffersPerPool == 0 {
-		device.pool.outboundElementPool.Put(msg)
-	} else {
-		device.pool.outboundElementReuseChan <- msg
-	}
+func (device *Device) PutOutboundElement(elem *QueueOutboundElement) {
+	elem.clearPointers()
+	device.pool.outboundElements.Put(elem)
 }

device/pools_test.go

@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+import (
+	"math/rand"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func TestWaitPool(t *testing.T) {
+	var wg sync.WaitGroup
+	trials := int32(100000)
+	if raceEnabled {
+		// This test can be very slow with -race.
+		trials /= 10
+	}
+	workers := runtime.NumCPU() + 2
+	if workers-4 <= 0 {
+		t.Skip("Not enough cores")
+	}
+	p := NewWaitPool(uint32(workers-4), func() interface{} { return make([]byte, 16) })
+	wg.Add(workers)
+	max := uint32(0)
+	updateMax := func() {
+		count := atomic.LoadUint32(&p.count)
+		if count > p.max {
+			t.Errorf("count (%d) > max (%d)", count, p.max)
+		}
+		for {
+			old := atomic.LoadUint32(&max)
+			if count <= old {
+				break
+			}
+			if atomic.CompareAndSwapUint32(&max, old, count) {
+				break
+			}
+		}
+	}
+	for i := 0; i < workers; i++ {
+		go func() {
+			defer wg.Done()
+			for atomic.AddInt32(&trials, -1) > 0 {
+				updateMax()
+				x := p.Get()
+				updateMax()
+				time.Sleep(time.Duration(rand.Intn(100)) * time.Microsecond)
+				updateMax()
+				p.Put(x)
+				updateMax()
+			}
+		}()
+	}
+	wg.Wait()
+	if max != p.max {
+		t.Errorf("Actual maximum count (%d) != ideal maximum count (%d)", max, p.max)
+	}
+}
+
+func BenchmarkWaitPool(b *testing.B) {
+	var wg sync.WaitGroup
+	trials := int32(b.N)
+	workers := runtime.NumCPU() + 2
+	if workers-4 <= 0 {
+		b.Skip("Not enough cores")
+	}
+	p := NewWaitPool(uint32(workers-4), func() interface{} { return make([]byte, 16) })
+	wg.Add(workers)
+	b.ResetTimer()
+	for i := 0; i < workers; i++ {
+		go func() {
+			defer wg.Done()
+			for atomic.AddInt32(&trials, -1) > 0 {
+				x := p.Get()
+				time.Sleep(time.Duration(rand.Intn(100)) * time.Microsecond)
+				p.Put(x)
+			}
+		}()
+	}
+	wg.Wait()
+}

device/queueconstants_android.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -8,6 +8,7 @@ package device
 /* Reduce memory consumption for Android */
 
 const (
+	QueueStagedSize            = 128
 	QueueOutboundSize          = 1024
 	QueueInboundSize           = 1024
 	QueueHandshakeSize         = 1024

device/queueconstants_default.go

@@ -2,12 +2,13 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 const (
+	QueueStagedSize            = 128
 	QueueOutboundSize          = 1024
 	QueueInboundSize           = 1024
 	QueueHandshakeSize         = 1024

device/queueconstants_ios.go

@@ -2,7 +2,7 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -10,6 +10,7 @@ package device
 /* Fit within memory limits for iOS's Network Extension API, which has stricter requirements */
 
 const (
+	QueueStagedSize            = 128
 	QueueOutboundSize          = 1024
 	QueueInboundSize           = 1024
 	QueueHandshakeSize         = 1024

device/race_disabled_test.go

@@ -0,0 +1,10 @@
+//+build !race
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+const raceEnabled = false

device/race_enabled_test.go

@@ -0,0 +1,10 @@
+//+build race
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package device
+
+const raceEnabled = true

device/receive.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -8,8 +8,8 @@ package device
 import (
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"net"
-	"strconv"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -17,57 +17,35 @@ import (
 	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/net/ipv4"
 	"golang.org/x/net/ipv6"
+
+	"golang.zx2c4.com/wireguard/conn"
 )
 
 type QueueHandshakeElement struct {
 	msgType  uint32
 	packet   []byte
-	endpoint Endpoint
+	endpoint conn.Endpoint
 	buffer   *[MaxMessageSize]byte
 }
 
 type QueueInboundElement struct {
-	dropped int32
 	sync.Mutex
 	buffer   *[MaxMessageSize]byte
 	packet   []byte
 	counter  uint64
 	keypair  *Keypair
-	endpoint Endpoint
+	endpoint conn.Endpoint
 }
 
-func (elem *QueueInboundElement) Drop() {
-	atomic.StoreInt32(&elem.dropped, AtomicTrue)
-}
-
-func (elem *QueueInboundElement) IsDropped() bool {
-	return atomic.LoadInt32(&elem.dropped) == AtomicTrue
-}
-
-func (device *Device) addToInboundAndDecryptionQueues(inboundQueue chan *QueueInboundElement, decryptionQueue chan *QueueInboundElement, element *QueueInboundElement) bool {
-	select {
-	case inboundQueue <- element:
-		select {
-		case decryptionQueue <- element:
-			return true
-		default:
-			element.Drop()
-			element.Unlock()
-			return false
-		}
-	default:
-		device.PutInboundElement(element)
-		return false
-	}
-}
-
-func (device *Device) addToHandshakeQueue(queue chan QueueHandshakeElement, element QueueHandshakeElement) bool {
-	select {
-	case queue <- element:
-		return true
-	default:
-		return false
-	}
+// clearPointers clears elem fields that contain pointers.
+// This makes the garbage collector's life easier and
+// avoids accidentally keeping other objects around unnecessarily.
+// It also reduces the possible collateral damage from use-after-free bugs.
+func (elem *QueueInboundElement) clearPointers() {
+	elem.buffer = nil
+	elem.packet = nil
+	elem.keypair = nil
+	elem.endpoint = nil
 }
 
 /* Called when a new authenticated message has been received
@@ -90,16 +68,15 @@ func (peer *Peer) keepKeyFreshReceiving() {
  * Every time the bind is updated a new routine is started for
  * IPv4 and IPv6 (separately)
  */
-func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
-
-	logDebug := device.log.Debug
+func (device *Device) RoutineReceiveIncoming(IP int, bind conn.Bind) {
 	defer func() {
-		logDebug.Println("Routine: receive incoming IPv" + strconv.Itoa(IP) + " - stopped")
+		device.log.Verbosef("Routine: receive incoming IPv%d - stopped", IP)
+		device.queue.decryption.wg.Done()
+		device.queue.handshake.wg.Done()
 		device.net.stopping.Done()
 	}()
 
-	logDebug.Println("Routine: receive incoming IPv" + strconv.Itoa(IP) + " - started")
-	device.net.starting.Done()
+	device.log.Verbosef("Routine: receive incoming IPv%d - started", IP)
 
 	// receive datagrams until conn is closed
 
@@ -108,13 +85,11 @@ func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
 	var (
 		err         error
 		size        int
-		endpoint Endpoint
+		endpoint    conn.Endpoint
+		deathSpiral int
 	)
 
 	for {
-
-		// read next datagram
-
 		switch IP {
 		case ipv4.Version:
 			size, endpoint, err = bind.ReceiveIPv4(buffer[:])
@@ -126,8 +101,18 @@ func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
 
 		if err != nil {
 			device.PutMessageBuffer(buffer)
+			if errors.Is(err, conn.NetErrClosed) {
 				return
 			}
+			device.log.Errorf("Failed to receive packet: %v", err)
+			if deathSpiral < 10 {
+				deathSpiral++
+				time.Sleep(time.Second / 3)
+				continue
+			}
+			return
+		}
+		deathSpiral = 0
 
 		if size < MinMessageSize {
 			continue
@@ -175,20 +160,19 @@ func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
 			elem.packet = packet
 			elem.buffer = buffer
 			elem.keypair = keypair
-			elem.dropped = AtomicFalse
 			elem.endpoint = endpoint
 			elem.counter = 0
 			elem.Mutex = sync.Mutex{}
 			elem.Lock()
 
 			// add to decryption queues
-
 			if peer.isRunning.Get() {
-				if device.addToInboundAndDecryptionQueues(peer.queue.inbound, device.queue.decryption, elem) {
+				peer.queue.inbound.c <- elem
+				device.queue.decryption.c <- elem
 				buffer = device.GetMessageBuffer()
+			} else {
+				device.PutInboundElement(elem)
 			}
-			}
-
 			continue
 
 		// otherwise it is a fixed size & handshake related packet
@@ -203,75 +187,40 @@ func (device *Device) RoutineReceiveIncoming(IP int, bind Bind) {
 			okay = len(packet) == MessageCookieReplySize
 
 		default:
-			logDebug.Println("Received message with unknown type")
+			device.log.Verbosef("Received message with unknown type")
 		}
 
 		if okay {
-			if (device.addToHandshakeQueue(
-				device.queue.handshake,
-				QueueHandshakeElement{
+			select {
+			case device.queue.handshake.c <- QueueHandshakeElement{
 				msgType:  msgType,
 				buffer:   buffer,
 				packet:   packet,
 				endpoint: endpoint,
-				},
-			)) {
+			}:
 				buffer = device.GetMessageBuffer()
+			default:
 			}
 		}
 	}
 }
 
 func (device *Device) RoutineDecryption() {
-
 	var nonce [chacha20poly1305.NonceSize]byte
 
-	logDebug := device.log.Debug
-	defer func() {
-		logDebug.Println("Routine: decryption worker - stopped")
-		device.state.stopping.Done()
-	}()
-	logDebug.Println("Routine: decryption worker - started")
-	device.state.starting.Done()
-
-	for {
-		select {
-		case <-device.signals.stop:
-			return
-
-		case elem, ok := <-device.queue.decryption:
-
-			if !ok {
-				return
-			}
-
-			// check if dropped
-
-			if elem.IsDropped() {
-				continue
-			}
+	defer device.log.Verbosef("Routine: decryption worker - stopped")
+	device.log.Verbosef("Routine: decryption worker - started")
 
+	for elem := range device.queue.decryption.c {
 		// split message into fields
-
 		counter := elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent]
 		content := elem.packet[MessageTransportOffsetContent:]
 
-			// expand nonce
-
-			nonce[0x4] = counter[0x0]
-			nonce[0x5] = counter[0x1]
-			nonce[0x6] = counter[0x2]
-			nonce[0x7] = counter[0x3]
-
-			nonce[0x8] = counter[0x4]
-			nonce[0x9] = counter[0x5]
-			nonce[0xa] = counter[0x6]
-			nonce[0xb] = counter[0x7]
-
 		// decrypt and release to consumer
-
 		var err error
 		elem.counter = binary.LittleEndian.Uint64(counter)
+		// copy counter to nonce
+		binary.LittleEndian.PutUint64(nonce[0x4:0xc], elem.counter)
 		elem.packet, err = elem.keypair.receive.Open(
 			content[:0],
 			nonce[:],
@@ -279,51 +228,22 @@ func (device *Device) RoutineDecryption() {
 			nil,
 		)
 		if err != nil {
-				elem.Drop()
-				device.PutMessageBuffer(elem.buffer)
+			elem.packet = nil
 		}
 		elem.Unlock()
 	}
-	}
 }
 
 /* Handles incoming packets related to handshake
  */
 func (device *Device) RoutineHandshake() {
-
-	logInfo := device.log.Info
-	logError := device.log.Error
-	logDebug := device.log.Debug
-
-	var elem QueueHandshakeElement
-	var ok bool
-
 	defer func() {
-		logDebug.Println("Routine: handshake worker - stopped")
-		device.state.stopping.Done()
-		if elem.buffer != nil {
-			device.PutMessageBuffer(elem.buffer)
-		}
+		device.log.Verbosef("Routine: handshake worker - stopped")
+		device.queue.encryption.wg.Done()
 	}()
+	device.log.Verbosef("Routine: handshake worker - started")
 
-	logDebug.Println("Routine: handshake worker - started")
-	device.state.starting.Done()
-
-	for {
-		if elem.buffer != nil {
-			device.PutMessageBuffer(elem.buffer)
-			elem.buffer = nil
-		}
-
-		select {
-		case elem, ok = <-device.queue.handshake:
-		case <-device.signals.stop:
-			return
-		}
-
-		if !ok {
-			return
-		}
+	for elem := range device.queue.handshake.c {
 
 		// handle cookie fields and ratelimiting
 
@@ -337,8 +257,8 @@ func (device *Device) RoutineHandshake() {
 			reader := bytes.NewReader(elem.packet)
 			err := binary.Read(reader, binary.LittleEndian, &reply)
 			if err != nil {
-				logDebug.Println("Failed to decode cookie reply")
-				return
+				device.log.Verbosef("Failed to decode cookie reply")
+				goto skip
 			}
 
 			// lookup peer from index
@@ -346,27 +266,27 @@ func (device *Device) RoutineHandshake() {
 			entry := device.indexTable.Lookup(reply.Receiver)
 
 			if entry.peer == nil {
-				continue
+				goto skip
 			}
 
 			// consume reply
 
 			if peer := entry.peer; peer.isRunning.Get() {
-				logDebug.Println("Receiving cookie response from ", elem.endpoint.DstToString())
+				device.log.Verbosef("Receiving cookie response from %s", elem.endpoint.DstToString())
 				if !peer.cookieGenerator.ConsumeReply(&reply) {
-					logDebug.Println("Could not decrypt invalid cookie response")
+					device.log.Verbosef("Could not decrypt invalid cookie response")
 				}
 			}
 
-			continue
+			goto skip
 
 		case MessageInitiationType, MessageResponseType:
 
 			// check mac fields and maybe ratelimit
 
 			if !device.cookieChecker.CheckMAC1(elem.packet) {
-				logDebug.Println("Received packet with invalid mac1")
-				continue
+				device.log.Verbosef("Received packet with invalid mac1")
+				goto skip
 			}
 
 			// endpoints destination address is the source of the datagram
@@ -377,19 +297,19 @@ func (device *Device) RoutineHandshake() {
 
 				if !device.cookieChecker.CheckMAC2(elem.packet, elem.endpoint.DstToBytes()) {
 					device.SendHandshakeCookie(&elem)
-					continue
+					goto skip
 				}
 
 				// check ratelimiter
 
 				if !device.rate.limiter.Allow(elem.endpoint.DstIP()) {
-					continue
+					goto skip
 				}
 			}
 
 		default:
-			logError.Println("Invalid packet ended up in the handshake queue")
-			continue
+			device.log.Errorf("Invalid packet ended up in the handshake queue")
+			goto skip
 		}
 
 		// handle handshake initiation/response content
@@ -403,19 +323,16 @@ func (device *Device) RoutineHandshake() {
 			reader := bytes.NewReader(elem.packet)
 			err := binary.Read(reader, binary.LittleEndian, &msg)
 			if err != nil {
-				logError.Println("Failed to decode initiation message")
-				continue
+				device.log.Errorf("Failed to decode initiation message")
+				goto skip
 			}
 
 			// consume initiation
 
 			peer := device.ConsumeMessageInitiation(&msg)
 			if peer == nil {
-				logInfo.Println(
-					"Received invalid initiation message from",
-					elem.endpoint.DstToString(),
-				)
-				continue
+				device.log.Verbosef("Received invalid initiation message from %s", elem.endpoint.DstToString())
+				goto skip
 			}
 
 			// update timers
@@ -426,7 +343,7 @@ func (device *Device) RoutineHandshake() {
 			// update endpoint
 			peer.SetEndpointFromPacket(elem.endpoint)
 
-			logDebug.Println(peer, "- Received handshake initiation")
+			device.log.Verbosef("%v - Received handshake initiation", peer)
 			atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
 
 			peer.SendHandshakeResponse()
@@ -439,25 +356,22 @@ func (device *Device) RoutineHandshake() {
 			reader := bytes.NewReader(elem.packet)
 			err := binary.Read(reader, binary.LittleEndian, &msg)
 			if err != nil {
-				logError.Println("Failed to decode response message")
-				continue
+				device.log.Errorf("Failed to decode response message")
+				goto skip
 			}
 
 			// consume response
 
 			peer := device.ConsumeMessageResponse(&msg)
 			if peer == nil {
-				logInfo.Println(
-					"Received invalid response message from",
-					elem.endpoint.DstToString(),
-				)
-				continue
+				device.log.Verbosef("Received invalid response message from %s", elem.endpoint.DstToString())
+				goto skip
 			}
 
 			// update endpoint
 			peer.SetEndpointFromPacket(elem.endpoint)
 
-			logDebug.Println(peer, "- Received handshake response")
+			device.log.Verbosef("%v - Received handshake response", peer)
 			atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)))
 
 			// update timers
@@ -470,88 +384,46 @@ func (device *Device) RoutineHandshake() {
 			err = peer.BeginSymmetricSession()
 
 			if err != nil {
-				logError.Println(peer, "- Failed to derive keypair:", err)
-				continue
+				device.log.Errorf("%v - Failed to derive keypair: %v", peer, err)
+				goto skip
 			}
 
 			peer.timersSessionDerived()
 			peer.timersHandshakeComplete()
 			peer.SendKeepalive()
-			select {
-			case peer.signals.newKeypairArrived <- struct{}{}:
-			default:
-			}
 		}
+	skip:
+		device.PutMessageBuffer(elem.buffer)
 	}
 }
 
 func (peer *Peer) RoutineSequentialReceiver() {
-
 	device := peer.device
-	logInfo := device.log.Info
-	logError := device.log.Error
-	logDebug := device.log.Debug
-
-	var elem *QueueInboundElement
-
 	defer func() {
-		logDebug.Println(peer, "- Routine: sequential receiver - stopped")
-		peer.routines.stopping.Done()
-		if elem != nil {
-			if !elem.IsDropped() {
-				device.PutMessageBuffer(elem.buffer)
-			}
-			device.PutInboundElement(elem)
-		}
+		device.log.Verbosef("%v - Routine: sequential receiver - stopped", peer)
+		peer.stopping.Done()
 	}()
+	device.log.Verbosef("%v - Routine: sequential receiver - started", peer)
 
-	logDebug.Println(peer, "- Routine: sequential receiver - started")
-
-	peer.routines.starting.Done()
-
-	for {
-		if elem != nil {
-			if !elem.IsDropped() {
-				device.PutMessageBuffer(elem.buffer)
-			}
-			device.PutInboundElement(elem)
-			elem = nil
-		}
-
-		var elemOk bool
-		select {
-		case <-peer.routines.stop:
-			return
-		case elem, elemOk = <-peer.queue.inbound:
-			if !elemOk {
+	for elem := range peer.queue.inbound.c {
+		if elem == nil {
 			return
 		}
-		}
-
-		// wait for decryption
-
+		var err error
 		elem.Lock()
-
-		if elem.IsDropped() {
-			continue
+		if elem.packet == nil {
+			// decryption failed
+			goto skip
 		}
 
-		// check for replay
-
 		if !elem.keypair.replayFilter.ValidateCounter(elem.counter, RejectAfterMessages) {
-			continue
+			goto skip
 		}
 
-		// update endpoint
 		peer.SetEndpointFromPacket(elem.endpoint)
-
-		// check if using new keypair
 		if peer.ReceivedWithKeypair(elem.keypair) {
 			peer.timersHandshakeComplete()
-			select {
-			case peer.signals.newKeypairArrived <- struct{}{}:
-			default:
-			}
+			peer.SendStagedPackets()
 		}
 
 		peer.keepKeyFreshReceiving()
@@ -559,89 +431,63 @@ func (peer *Peer) RoutineSequentialReceiver() {
 		peer.timersAnyAuthenticatedPacketReceived()
 		atomic.AddUint64(&peer.stats.rxBytes, uint64(len(elem.packet)+MinMessageSize))
 
-		// check for keepalive
-
 		if len(elem.packet) == 0 {
-			logDebug.Println(peer, "- Receiving keepalive packet")
-			continue
+			device.log.Verbosef("%v - Receiving keepalive packet", peer)
+			goto skip
 		}
 		peer.timersDataReceived()
 
-		// verify source and strip padding
-
 		switch elem.packet[0] >> 4 {
 		case ipv4.Version:
-
-			// strip padding
-
 			if len(elem.packet) < ipv4.HeaderLen {
-				continue
+				goto skip
 			}
-
 			field := elem.packet[IPv4offsetTotalLength : IPv4offsetTotalLength+2]
 			length := binary.BigEndian.Uint16(field)
 			if int(length) > len(elem.packet) || int(length) < ipv4.HeaderLen {
-				continue
+				goto skip
 			}
-
 			elem.packet = elem.packet[:length]
-
-			// verify IPv4 source
-
 			src := elem.packet[IPv4offsetSrc : IPv4offsetSrc+net.IPv4len]
 			if device.allowedips.LookupIPv4(src) != peer {
-				logInfo.Println(
-					"IPv4 packet with disallowed source address from",
-					peer,
-				)
-				continue
+				device.log.Verbosef("IPv4 packet with disallowed source address from %v", peer)
+				goto skip
 			}
 
 		case ipv6.Version:
-
-			// strip padding
-
 			if len(elem.packet) < ipv6.HeaderLen {
-				continue
+				goto skip
 			}
-
 			field := elem.packet[IPv6offsetPayloadLength : IPv6offsetPayloadLength+2]
 			length := binary.BigEndian.Uint16(field)
 			length += ipv6.HeaderLen
 			if int(length) > len(elem.packet) {
-				continue
+				goto skip
 			}
-
 			elem.packet = elem.packet[:length]
-
-			// verify IPv6 source
-
 			src := elem.packet[IPv6offsetSrc : IPv6offsetSrc+net.IPv6len]
 			if device.allowedips.LookupIPv6(src) != peer {
-				logInfo.Println(
-					"IPv6 packet with disallowed source address from",
-					peer,
-				)
-				continue
+				device.log.Verbosef("IPv6 packet with disallowed source address from %v", peer)
+				goto skip
 			}
 
 		default:
-			logInfo.Println("Packet with invalid IP version from", peer)
-			continue
+			device.log.Verbosef("Packet with invalid IP version from %v", peer)
+			goto skip
 		}
 
-		// write to tun device
-
-		offset := MessageTransportOffsetContent
-		_, err := device.tun.device.Write(elem.buffer[:offset+len(elem.packet)], offset)
-		if len(peer.queue.inbound) == 0 {
+		_, err = device.tun.device.Write(elem.buffer[:MessageTransportOffsetContent+len(elem.packet)], MessageTransportOffsetContent)
+		if err != nil && !device.isClosed() {
+			device.log.Errorf("Failed to write packet to TUN device: %v", err)
+		}
+		if len(peer.queue.inbound.c) == 0 {
 			err = device.tun.device.Flush()
 			if err != nil {
-				peer.device.log.Error.Printf("Unable to flush packets: %v", err)
+				peer.device.log.Errorf("Unable to flush packets: %v", err)
 			}
 		}
-		if err != nil && !device.isClosed.Get() {
-			logError.Println("Failed to write packet to TUN device:", err)
-		}
+	skip:
+		device.PutMessageBuffer(elem.buffer)
+		device.PutInboundElement(elem)
 	}
 }

device/send.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
@@ -43,7 +43,6 @@ import (
  */
 
 type QueueOutboundElement struct {
-	dropped int32
 	sync.Mutex
 	buffer  *[MaxMessageSize]byte // slice holding the packet data
 	packet  []byte                // slice of "buffer" (always!)
@@ -54,73 +53,38 @@ type QueueOutboundElement struct {
 
 func (device *Device) NewOutboundElement() *QueueOutboundElement {
 	elem := device.GetOutboundElement()
-	elem.dropped = AtomicFalse
 	elem.buffer = device.GetMessageBuffer()
 	elem.Mutex = sync.Mutex{}
 	elem.nonce = 0
-	elem.keypair = nil
-	elem.peer = nil
+	// keypair and peer were cleared (if necessary) by clearPointers.
 	return elem
 }
 
-func (elem *QueueOutboundElement) Drop() {
-	atomic.StoreInt32(&elem.dropped, AtomicTrue)
-}
-
-func (elem *QueueOutboundElement) IsDropped() bool {
-	return atomic.LoadInt32(&elem.dropped) == AtomicTrue
-}
-
-func addToNonceQueue(queue chan *QueueOutboundElement, element *QueueOutboundElement, device *Device) {
-	for {
-		select {
-		case queue <- element:
-			return
-		default:
-			select {
-			case old := <-queue:
-				device.PutMessageBuffer(old.buffer)
-				device.PutOutboundElement(old)
-			default:
-			}
-		}
-	}
-}
-
-func addToOutboundAndEncryptionQueues(outboundQueue chan *QueueOutboundElement, encryptionQueue chan *QueueOutboundElement, element *QueueOutboundElement) {
-	select {
-	case outboundQueue <- element:
-		select {
-		case encryptionQueue <- element:
-			return
-		default:
-			element.Drop()
-			element.peer.device.PutMessageBuffer(element.buffer)
-			element.Unlock()
-		}
-	default:
-		element.peer.device.PutMessageBuffer(element.buffer)
-		element.peer.device.PutOutboundElement(element)
-	}
+// clearPointers clears elem fields that contain pointers.
+// This makes the garbage collector's life easier and
+// avoids accidentally keeping other objects around unnecessarily.
+// It also reduces the possible collateral damage from use-after-free bugs.
+func (elem *QueueOutboundElement) clearPointers() {
+	elem.buffer = nil
+	elem.packet = nil
+	elem.keypair = nil
+	elem.peer = nil
 }
 
 /* Queues a keepalive if no packets are queued for peer
  */
-func (peer *Peer) SendKeepalive() bool {
-	if len(peer.queue.nonce) != 0 || peer.queue.packetInNonceQueueIsAwaitingKey.Get() || !peer.isRunning.Get() {
-		return false
-	}
+func (peer *Peer) SendKeepalive() {
+	if len(peer.queue.staged) == 0 && peer.isRunning.Get() {
 		elem := peer.device.NewOutboundElement()
-	elem.packet = nil
 		select {
-	case peer.queue.nonce <- elem:
-		peer.device.log.Debug.Println(peer, "- Sending keepalive packet")
-		return true
+		case peer.queue.staged <- elem:
+			peer.device.log.Verbosef("%v - Sending keepalive packet", peer)
 		default:
 			peer.device.PutMessageBuffer(elem.buffer)
 			peer.device.PutOutboundElement(elem)
-		return false
 		}
+	}
+	peer.SendStagedPackets()
 }
 
 func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
@@ -143,11 +107,11 @@ func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
 	peer.handshake.lastSentHandshake = time.Now()
 	peer.handshake.mutex.Unlock()
 
-	peer.device.log.Debug.Println(peer, "- Sending handshake initiation")
+	peer.device.log.Verbosef("%v - Sending handshake initiation", peer)
 
 	msg, err := peer.device.CreateMessageInitiation(peer)
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to create initiation message:", err)
+		peer.device.log.Errorf("%v - Failed to create initiation message: %v", peer, err)
 		return err
 	}
 
@@ -162,7 +126,7 @@ func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
 
 	err = peer.SendBuffer(packet)
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to send handshake initiation", err)
+		peer.device.log.Errorf("%v - Failed to send handshake initiation: %v", peer, err)
 	}
 	peer.timersHandshakeInitiated()
 
@@ -174,11 +138,11 @@ func (peer *Peer) SendHandshakeResponse() error {
 	peer.handshake.lastSentHandshake = time.Now()
 	peer.handshake.mutex.Unlock()
 
-	peer.device.log.Debug.Println(peer, "- Sending handshake response")
+	peer.device.log.Verbosef("%v - Sending handshake response", peer)
 
 	response, err := peer.device.CreateMessageResponse(peer)
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to create response message:", err)
+		peer.device.log.Errorf("%v - Failed to create response message: %v", peer, err)
 		return err
 	}
 
@@ -190,7 +154,7 @@ func (peer *Peer) SendHandshakeResponse() error {
 
 	err = peer.BeginSymmetricSession()
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to derive keypair:", err)
+		peer.device.log.Errorf("%v - Failed to derive keypair: %v", peer, err)
 		return err
 	}
 
@@ -200,19 +164,18 @@ func (peer *Peer) SendHandshakeResponse() error {
 
 	err = peer.SendBuffer(packet)
 	if err != nil {
-		peer.device.log.Error.Println(peer, "- Failed to send handshake response", err)
+		peer.device.log.Errorf("%v - Failed to send handshake response: %v", peer, err)
 	}
 	return err
 }
 
 func (device *Device) SendHandshakeCookie(initiatingElem *QueueHandshakeElement) error {
-
-	device.log.Debug.Println("Sending cookie response for denied handshake message for", initiatingElem.endpoint.DstToString())
+	device.log.Verbosef("Sending cookie response for denied handshake message for %v", initiatingElem.endpoint.DstToString())
 
 	sender := binary.LittleEndian.Uint32(initiatingElem.packet[4:8])
 	reply, err := device.cookieChecker.CreateReply(initiatingElem.packet, sender, initiatingElem.endpoint.DstToBytes())
 	if err != nil {
-		device.log.Error.Println("Failed to create cookie reply:", err)
+		device.log.Errorf("Failed to create cookie reply: %v", err)
 		return err
 	}
 
@@ -235,22 +198,18 @@ func (peer *Peer) keepKeyFreshSending() {
 }
 
 /* Reads packets from the TUN and inserts
- * into nonce queue for peer
+ * into staged queue for peer
  *
  * Obs. Single instance per TUN device
  */
 func (device *Device) RoutineReadFromTUN() {
-
-	logDebug := device.log.Debug
-	logError := device.log.Error
-
 	defer func() {
-		logDebug.Println("Routine: TUN reader - stopped")
+		device.log.Verbosef("Routine: TUN reader - stopped")
 		device.state.stopping.Done()
+		device.queue.encryption.wg.Done()
 	}()
 
-	logDebug.Println("Routine: TUN reader - started")
-	device.state.starting.Done()
+	device.log.Verbosef("Routine: TUN reader - started")
 
 	var elem *QueueOutboundElement
 
@@ -267,8 +226,8 @@ func (device *Device) RoutineReadFromTUN() {
 		size, err := device.tun.device.Read(elem.buffer[:], offset)
 
 		if err != nil {
-			if !device.isClosed.Get() {
-				logError.Println("Failed to read packet from TUN device:", err)
+			if !device.isClosed() {
+				device.log.Errorf("Failed to read packet from TUN device: %v", err)
 				device.Close()
 			}
 			device.PutMessageBuffer(elem.buffer)
@@ -301,207 +260,117 @@ func (device *Device) RoutineReadFromTUN() {
 			peer = device.allowedips.LookupIPv6(dst)
 
 		default:
-			logDebug.Println("Received packet with unknown IP version")
+			device.log.Verbosef("Received packet with unknown IP version")
 		}
 
 		if peer == nil {
 			continue
 		}
-
-		// insert into nonce/pre-handshake queue
-
 		if peer.isRunning.Get() {
-			if peer.queue.packetInNonceQueueIsAwaitingKey.Get() {
-				peer.SendHandshakeInitiation(false)
-			}
-			addToNonceQueue(peer.queue.nonce, elem, device)
+			peer.StagePacket(elem)
 			elem = nil
+			peer.SendStagedPackets()
 		}
 	}
 }
 
-func (peer *Peer) FlushNonceQueue() {
+func (peer *Peer) StagePacket(elem *QueueOutboundElement) {
+	for {
 		select {
-	case peer.signals.flushNonceQueue <- struct{}{}:
+		case peer.queue.staged <- elem:
+			return
 		default:
 		}
+		select {
+		case tooOld := <-peer.queue.staged:
+			peer.device.PutMessageBuffer(tooOld.buffer)
+			peer.device.PutOutboundElement(tooOld)
+		default:
+		}
+	}
 }
 
-/* Queues packets when there is no handshake.
- * Then assigns nonces to packets sequentially
- * and creates "work" structs for workers
- *
- * Obs. A single instance per peer
- */
-func (peer *Peer) RoutineNonce() {
-	var keypair *Keypair
-
-	device := peer.device
-	logDebug := device.log.Debug
-
-	flush := func() {
-		for {
-			select {
-			case elem := <-peer.queue.nonce:
-				device.PutMessageBuffer(elem.buffer)
-				device.PutOutboundElement(elem)
-			default:
-				return
-			}
-		}
-	}
-
-	defer func() {
-		flush()
-		logDebug.Println(peer, "- Routine: nonce worker - stopped")
-		peer.queue.packetInNonceQueueIsAwaitingKey.Set(false)
-		peer.routines.stopping.Done()
-	}()
-
-	peer.routines.starting.Done()
-	logDebug.Println(peer, "- Routine: nonce worker - started")
-
-	for {
-	NextPacket:
-		peer.queue.packetInNonceQueueIsAwaitingKey.Set(false)
-
-		select {
-		case <-peer.routines.stop:
-			return
-
-		case <-peer.signals.flushNonceQueue:
-			flush()
-			goto NextPacket
-
-		case elem, ok := <-peer.queue.nonce:
-
-			if !ok {
+func (peer *Peer) SendStagedPackets() {
+top:
+	if len(peer.queue.staged) == 0 || !peer.device.isUp() {
 		return
 	}
 
-			// make sure to always pick the newest key
-
-			for {
-
-				// check validity of newest key pair
-
-				keypair = peer.keypairs.Current()
-				if keypair != nil && keypair.sendNonce < RejectAfterMessages {
-					if time.Since(keypair.created) < RejectAfterTime {
-						break
-					}
-				}
-				peer.queue.packetInNonceQueueIsAwaitingKey.Set(true)
-
-				// no suitable key pair, request for new handshake
-
-				select {
-				case <-peer.signals.newKeypairArrived:
-				default:
-				}
-
+	keypair := peer.keypairs.Current()
+	if keypair == nil || atomic.LoadUint64(&keypair.sendNonce) >= RejectAfterMessages || time.Since(keypair.created) >= RejectAfterTime {
 		peer.SendHandshakeInitiation(false)
-
-				// wait for key to be established
-
-				logDebug.Println(peer, "- Awaiting keypair")
-
-				select {
-				case <-peer.signals.newKeypairArrived:
-					logDebug.Println(peer, "- Obtained awaited keypair")
-
-				case <-peer.signals.flushNonceQueue:
-					device.PutMessageBuffer(elem.buffer)
-					device.PutOutboundElement(elem)
-					flush()
-					goto NextPacket
-
-				case <-peer.routines.stop:
-					device.PutMessageBuffer(elem.buffer)
-					device.PutOutboundElement(elem)
 		return
 	}
-			}
-			peer.queue.packetInNonceQueueIsAwaitingKey.Set(false)
-
-			// populate work element
 
+	for {
+		select {
+		case elem := <-peer.queue.staged:
 			elem.peer = peer
 			elem.nonce = atomic.AddUint64(&keypair.sendNonce, 1) - 1
-
-			// double check in case of race condition added by future code
-
 			if elem.nonce >= RejectAfterMessages {
 				atomic.StoreUint64(&keypair.sendNonce, RejectAfterMessages)
-				device.PutMessageBuffer(elem.buffer)
-				device.PutOutboundElement(elem)
-				goto NextPacket
+				peer.StagePacket(elem) // XXX: Out of order, but we can't front-load go chans
+				goto top
 			}
 
 			elem.keypair = keypair
-			elem.dropped = AtomicFalse
 			elem.Lock()
 
 			// add to parallel and sequential queue
-			addToOutboundAndEncryptionQueues(peer.queue.outbound, device.queue.encryption, elem)
+			if peer.isRunning.Get() {
+				peer.queue.outbound.c <- elem
+				peer.device.queue.encryption.c <- elem
+			} else {
+				peer.device.PutMessageBuffer(elem.buffer)
+				peer.device.PutOutboundElement(elem)
+			}
+		default:
+			return
 		}
 	}
 }
 
+func (peer *Peer) FlushStagedPackets() {
+	for {
+		select {
+		case elem := <-peer.queue.staged:
+			peer.device.PutMessageBuffer(elem.buffer)
+			peer.device.PutOutboundElement(elem)
+		default:
+			return
+		}
+	}
+}
+
+func calculatePaddingSize(packetSize, mtu int) int {
+	lastUnit := packetSize
+	if mtu == 0 {
+		return ((lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1)) - lastUnit
+	}
+	if lastUnit > mtu {
+		lastUnit %= mtu
+	}
+	paddedSize := ((lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1))
+	if paddedSize > mtu {
+		paddedSize = mtu
+	}
+	return paddedSize - lastUnit
+}
+
 /* Encrypts the elements in the queue
  * and marks them for sequential consumption (by releasing the mutex)
  *
  * Obs. One instance per core
  */
 func (device *Device) RoutineEncryption() {
-
+	var paddingZeros [PaddingMultiple]byte
 	var nonce [chacha20poly1305.NonceSize]byte
 
-	logDebug := device.log.Debug
-
-	defer func() {
-		for {
-			select {
-			case elem, ok := <-device.queue.encryption:
-				if ok && !elem.IsDropped() {
-					elem.Drop()
-					device.PutMessageBuffer(elem.buffer)
-					elem.Unlock()
-				}
-			default:
-				goto out
-			}
-		}
-	out:
-		logDebug.Println("Routine: encryption worker - stopped")
-		device.state.stopping.Done()
-	}()
-
-	logDebug.Println("Routine: encryption worker - started")
-	device.state.starting.Done()
-
-	for {
-
-		// fetch next element
-
-		select {
-		case <-device.signals.stop:
-			return
-
-		case elem, ok := <-device.queue.encryption:
-
-			if !ok {
-				return
-			}
-
-			// check if dropped
-
-			if elem.IsDropped() {
-				continue
-			}
+	defer device.log.Verbosef("Routine: encryption worker - stopped")
+	device.log.Verbosef("Routine: encryption worker - started")
 
+	for elem := range device.queue.encryption.c {
 		// populate header fields
-
 		header := elem.buffer[:MessageTransportHeaderSize]
 
 		fieldType := header[0:4]
@@ -513,16 +382,8 @@ func (device *Device) RoutineEncryption() {
 		binary.LittleEndian.PutUint64(fieldNonce, elem.nonce)
 
 		// pad content to multiple of 16
-
-			mtu := int(atomic.LoadInt32(&device.tun.mtu))
-			lastUnit := len(elem.packet) % mtu
-			paddedSize := (lastUnit + PaddingMultiple - 1) & ^(PaddingMultiple - 1)
-			if paddedSize > mtu {
-				paddedSize = mtu
-			}
-			for i := len(elem.packet); i < paddedSize; i++ {
-				elem.packet = append(elem.packet, 0)
-			}
+		paddingSize := calculatePaddingSize(len(elem.packet), int(atomic.LoadInt32(&device.tun.mtu)))
+		elem.packet = append(elem.packet, paddingZeros[:paddingSize]...)
 
 		// encrypt content and release to consumer
 
@@ -535,7 +396,6 @@ func (device *Device) RoutineEncryption() {
 		)
 		elem.Unlock()
 	}
-	}
 }
 
 /* Sequentially reads packets from queue and sends to endpoint
@@ -544,50 +404,26 @@ func (device *Device) RoutineEncryption() {
  * The routine terminates then the outbound queue is closed.
  */
 func (peer *Peer) RoutineSequentialSender() {
-
 	device := peer.device
-
-	logDebug := device.log.Debug
-	logError := device.log.Error
-
 	defer func() {
-		for {
-			select {
-			case elem, ok := <-peer.queue.outbound:
-				if ok {
-					if !elem.IsDropped() {
-						device.PutMessageBuffer(elem.buffer)
-						elem.Drop()
-					}
-					device.PutOutboundElement(elem)
-				}
-			default:
-				goto out
-			}
-		}
-	out:
-		logDebug.Println(peer, "- Routine: sequential sender - stopped")
-		peer.routines.stopping.Done()
+		defer device.log.Verbosef("%v - Routine: sequential sender - stopped", peer)
+		peer.stopping.Done()
 	}()
+	device.log.Verbosef("%v - Routine: sequential sender - started", peer)
 
-	logDebug.Println(peer, "- Routine: sequential sender - started")
-
-	peer.routines.starting.Done()
-
-	for {
-		select {
-
-		case <-peer.routines.stop:
-			return
-
-		case elem, ok := <-peer.queue.outbound:
-
-			if !ok {
+	for elem := range peer.queue.outbound.c {
+		if elem == nil {
 			return
 		}
-
 		elem.Lock()
-			if elem.IsDropped() {
+		if !peer.isRunning.Get() {
+			// peer has been stopped; return re-usable elems to the shared pool.
+			// This is an optimization only. It is possible for the peer to be stopped
+			// immediately after this check, in which case, elem will get processed.
+			// The timers and SendBuffer code are resilient to a few stragglers.
+			// TODO(josharian): rework peer shutdown order to ensure
+			// that we never accidentally keep timers alive longer than necessary.
+			device.PutMessageBuffer(elem.buffer)
 			device.PutOutboundElement(elem)
 			continue
 		}
@@ -604,11 +440,10 @@ func (peer *Peer) RoutineSequentialSender() {
 		device.PutMessageBuffer(elem.buffer)
 		device.PutOutboundElement(elem)
 		if err != nil {
-				logError.Println(peer, "- Failed to send data packet", err)
+			device.log.Errorf("%v - Failed to send data packet: %v", peer, err)
 			continue
 		}
 
 		peer.keepKeyFreshSending()
 	}
-	}
 }

device/sticky_default.go

@@ -0,0 +1,12 @@
+// +build !linux android
+
+package device
+
+import (
+	"golang.zx2c4.com/wireguard/conn"
+	"golang.zx2c4.com/wireguard/rwcancel"
+)
+
+func (device *Device) startRouteListener(bind conn.Bind) (*rwcancel.RWCancel, error) {
+	return nil, nil
+}

device/sticky_linux.go

@@ -0,0 +1,218 @@
+// +build !android
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ *
+ * This implements userspace semantics of "sticky sockets", modeled after
+ * WireGuard's kernelspace implementation. This is more or less a straight port
+ * of the sticky-sockets.c example code:
+ * https://git.zx2c4.com/WireGuard/tree/contrib/examples/sticky-sockets/sticky-sockets.c
+ *
+ * Currently there is no way to achieve this within the net package:
+ * See e.g. https://github.com/golang/go/issues/17930
+ * So this code is remains platform dependent.
+ */
+
+package device
+
+import (
+	"sync"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+	"golang.zx2c4.com/wireguard/conn"
+	"golang.zx2c4.com/wireguard/rwcancel"
+)
+
+func (device *Device) startRouteListener(bind conn.Bind) (*rwcancel.RWCancel, error) {
+	netlinkSock, err := createNetlinkRouteSocket()
+	if err != nil {
+		return nil, err
+	}
+	netlinkCancel, err := rwcancel.NewRWCancel(netlinkSock)
+	if err != nil {
+		unix.Close(netlinkSock)
+		return nil, err
+	}
+
+	go device.routineRouteListener(bind, netlinkSock, netlinkCancel)
+
+	return netlinkCancel, nil
+}
+
+func (device *Device) routineRouteListener(bind conn.Bind, netlinkSock int, netlinkCancel *rwcancel.RWCancel) {
+	type peerEndpointPtr struct {
+		peer     *Peer
+		endpoint *conn.Endpoint
+	}
+	var reqPeer map[uint32]peerEndpointPtr
+	var reqPeerLock sync.Mutex
+
+	defer netlinkCancel.Close()
+	defer unix.Close(netlinkSock)
+
+	for msg := make([]byte, 1<<16); ; {
+		var err error
+		var msgn int
+		for {
+			msgn, _, _, _, err = unix.Recvmsg(netlinkSock, msg[:], nil, 0)
+			if err == nil || !rwcancel.RetryAfterError(err) {
+				break
+			}
+			if !netlinkCancel.ReadyRead() {
+				return
+			}
+		}
+		if err != nil {
+			return
+		}
+
+		for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
+
+			hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
+
+			if uint(hdr.Len) > uint(len(remain)) {
+				break
+			}
+
+			switch hdr.Type {
+			case unix.RTM_NEWROUTE, unix.RTM_DELROUTE:
+				if hdr.Seq <= MaxPeers && hdr.Seq > 0 {
+					if uint(len(remain)) < uint(hdr.Len) {
+						break
+					}
+					if hdr.Len > unix.SizeofNlMsghdr+unix.SizeofRtMsg {
+						attr := remain[unix.SizeofNlMsghdr+unix.SizeofRtMsg:]
+						for {
+							if uint(len(attr)) < uint(unix.SizeofRtAttr) {
+								break
+							}
+							attrhdr := *(*unix.RtAttr)(unsafe.Pointer(&attr[0]))
+							if attrhdr.Len < unix.SizeofRtAttr || uint(len(attr)) < uint(attrhdr.Len) {
+								break
+							}
+							if attrhdr.Type == unix.RTA_OIF && attrhdr.Len == unix.SizeofRtAttr+4 {
+								ifidx := *(*uint32)(unsafe.Pointer(&attr[unix.SizeofRtAttr]))
+								reqPeerLock.Lock()
+								if reqPeer == nil {
+									reqPeerLock.Unlock()
+									break
+								}
+								pePtr, ok := reqPeer[hdr.Seq]
+								reqPeerLock.Unlock()
+								if !ok {
+									break
+								}
+								pePtr.peer.Lock()
+								if &pePtr.peer.endpoint != pePtr.endpoint {
+									pePtr.peer.Unlock()
+									break
+								}
+								if uint32(pePtr.peer.endpoint.(*conn.NativeEndpoint).Src4().Ifindex) == ifidx {
+									pePtr.peer.Unlock()
+									break
+								}
+								pePtr.peer.endpoint.(*conn.NativeEndpoint).ClearSrc()
+								pePtr.peer.Unlock()
+							}
+							attr = attr[attrhdr.Len:]
+						}
+					}
+					break
+				}
+				reqPeerLock.Lock()
+				reqPeer = make(map[uint32]peerEndpointPtr)
+				reqPeerLock.Unlock()
+				go func() {
+					device.peers.RLock()
+					i := uint32(1)
+					for _, peer := range device.peers.keyMap {
+						peer.RLock()
+						if peer.endpoint == nil {
+							peer.RUnlock()
+							continue
+						}
+						nativeEP, _ := peer.endpoint.(*conn.NativeEndpoint)
+						if nativeEP == nil {
+							peer.RUnlock()
+							continue
+						}
+						if nativeEP.IsV6() || nativeEP.Src4().Ifindex == 0 {
+							peer.RUnlock()
+							break
+						}
+						nlmsg := struct {
+							hdr     unix.NlMsghdr
+							msg     unix.RtMsg
+							dsthdr  unix.RtAttr
+							dst     [4]byte
+							srchdr  unix.RtAttr
+							src     [4]byte
+							markhdr unix.RtAttr
+							mark    uint32
+						}{
+							unix.NlMsghdr{
+								Type:  uint16(unix.RTM_GETROUTE),
+								Flags: unix.NLM_F_REQUEST,
+								Seq:   i,
+							},
+							unix.RtMsg{
+								Family:  unix.AF_INET,
+								Dst_len: 32,
+								Src_len: 32,
+							},
+							unix.RtAttr{
+								Len:  8,
+								Type: unix.RTA_DST,
+							},
+							nativeEP.Dst4().Addr,
+							unix.RtAttr{
+								Len:  8,
+								Type: unix.RTA_SRC,
+							},
+							nativeEP.Src4().Src,
+							unix.RtAttr{
+								Len:  8,
+								Type: unix.RTA_MARK,
+							},
+							uint32(bind.LastMark()),
+						}
+						nlmsg.hdr.Len = uint32(unsafe.Sizeof(nlmsg))
+						reqPeerLock.Lock()
+						reqPeer[i] = peerEndpointPtr{
+							peer:     peer,
+							endpoint: &peer.endpoint,
+						}
+						reqPeerLock.Unlock()
+						peer.RUnlock()
+						i++
+						_, err := netlinkCancel.Write((*[unsafe.Sizeof(nlmsg)]byte)(unsafe.Pointer(&nlmsg))[:])
+						if err != nil {
+							break
+						}
+					}
+					device.peers.RUnlock()
+				}()
+			}
+			remain = remain[hdr.Len:]
+		}
+	}
+}
+
+func createNetlinkRouteSocket() (int, error) {
+	sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, unix.NETLINK_ROUTE)
+	if err != nil {
+		return -1, err
+	}
+	saddr := &unix.SockaddrNetlink{
+		Family: unix.AF_NETLINK,
+		Groups: unix.RTMGRP_IPV4_ROUTE,
+	}
+	err = unix.Bind(sock, saddr)
+	if err != nil {
+		unix.Close(sock)
+		return -1, err
+	}
+	return sock, nil
+}

device/timers.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  *
  * This is based heavily on timers.c from the kernel implementation.
  */
@@ -14,10 +14,8 @@ import (
 	"time"
 )
 
-/* This Timer structure and related functions should roughly copy the interface of
- * the Linux kernel's struct timer_list.
- */
-
+// A Timer manages time-based aspects of the WireGuard protocol.
+// Timer roughly copies the interface of the Linux kernel's struct timer_list.
 type Timer struct {
 	*time.Timer
 	modifyingLock sync.RWMutex
@@ -29,18 +27,17 @@ func (peer *Peer) NewTimer(expirationFunction func(*Peer)) *Timer {
 	timer := &Timer{}
 	timer.Timer = time.AfterFunc(time.Hour, func() {
 		timer.runningLock.Lock()
+		defer timer.runningLock.Unlock()
 
 		timer.modifyingLock.Lock()
 		if !timer.isPending {
 			timer.modifyingLock.Unlock()
-			timer.runningLock.Unlock()
 			return
 		}
 		timer.isPending = false
 		timer.modifyingLock.Unlock()
 
 		expirationFunction(peer)
-		timer.runningLock.Unlock()
 	})
 	timer.Stop()
 	return timer
@@ -74,12 +71,12 @@ func (timer *Timer) IsPending() bool {
 }
 
 func (peer *Peer) timersActive() bool {
-	return peer.isRunning.Get() && peer.device != nil && peer.device.isUp.Get() && len(peer.device.peers.keyMap) > 0
+	return peer.isRunning.Get() && peer.device != nil && peer.device.isUp() && !peer.device.peers.empty.Get()
 }
 
 func expiredRetransmitHandshake(peer *Peer) {
 	if atomic.LoadUint32(&peer.timers.handshakeAttempts) > MaxTimerHandshakes {
-		peer.device.log.Debug.Printf("%s - Handshake did not complete after %d attempts, giving up\n", peer, MaxTimerHandshakes+2)
+		peer.device.log.Verbosef("%s - Handshake did not complete after %d attempts, giving up", peer, MaxTimerHandshakes+2)
 
 		if peer.timersActive() {
 			peer.timers.sendKeepalive.Del()
@@ -88,7 +85,7 @@ func expiredRetransmitHandshake(peer *Peer) {
 		/* We drop all packets without a keypair and don't try again,
 		 * if we try unsuccessfully for too long to make a handshake.
 		 */
-		peer.FlushNonceQueue()
+		peer.FlushStagedPackets()
 
 		/* We set a timer for destroying any residue that might be left
 		 * of a partial exchange.
@@ -98,7 +95,7 @@ func expiredRetransmitHandshake(peer *Peer) {
 		}
 	} else {
 		atomic.AddUint32(&peer.timers.handshakeAttempts, 1)
-		peer.device.log.Debug.Printf("%s - Handshake did not complete after %d seconds, retrying (try %d)\n", peer, int(RekeyTimeout.Seconds()), atomic.LoadUint32(&peer.timers.handshakeAttempts)+1)
+		peer.device.log.Verbosef("%s - Handshake did not complete after %d seconds, retrying (try %d)", peer, int(RekeyTimeout.Seconds()), atomic.LoadUint32(&peer.timers.handshakeAttempts)+1)
 
 		/* We clear the endpoint address src address, in case this is the cause of trouble. */
 		peer.Lock()
@@ -122,7 +119,7 @@ func expiredSendKeepalive(peer *Peer) {
 }
 
 func expiredNewHandshake(peer *Peer) {
-	peer.device.log.Debug.Printf("%s - Retrying handshake because we stopped hearing back after %d seconds\n", peer, int((KeepaliveTimeout + RekeyTimeout).Seconds()))
+	peer.device.log.Verbosef("%s - Retrying handshake because we stopped hearing back after %d seconds", peer, int((KeepaliveTimeout + RekeyTimeout).Seconds()))
 	/* We clear the endpoint address src address, in case this is the cause of trouble. */
 	peer.Lock()
 	if peer.endpoint != nil {
@@ -134,12 +131,12 @@ func expiredNewHandshake(peer *Peer) {
 }
 
 func expiredZeroKeyMaterial(peer *Peer) {
-	peer.device.log.Debug.Printf("%s - Removing all keys, since we haven't received a new one in %d seconds\n", peer, int((RejectAfterTime * 3).Seconds()))
+	peer.device.log.Verbosef("%s - Removing all keys, since we haven't received a new one in %d seconds", peer, int((RejectAfterTime * 3).Seconds()))
 	peer.ZeroAndFlushAll()
 }
 
 func expiredPersistentKeepalive(peer *Peer) {
-	if peer.persistentKeepaliveInterval > 0 {
+	if atomic.LoadUint32(&peer.persistentKeepaliveInterval) > 0 {
 		peer.SendKeepalive()
 	}
 }
@@ -202,8 +199,9 @@ func (peer *Peer) timersSessionDerived() {
 
 /* Should be called before a packet with authentication -- keepalive, data, or handshake -- is sent, or after one is received. */
 func (peer *Peer) timersAnyAuthenticatedPacketTraversal() {
-	if peer.persistentKeepaliveInterval > 0 && peer.timersActive() {
-		peer.timers.persistentKeepalive.Mod(time.Duration(peer.persistentKeepaliveInterval) * time.Second)
+	keepalive := atomic.LoadUint32(&peer.persistentKeepaliveInterval)
+	if keepalive > 0 && peer.timersActive() {
+		peer.timers.persistentKeepalive.Mod(time.Duration(keepalive) * time.Second)
 	}
 }
 
@@ -213,6 +211,9 @@ func (peer *Peer) timersInit() {
 	peer.timers.newHandshake = peer.NewTimer(expiredNewHandshake)
 	peer.timers.zeroKeyMaterial = peer.NewTimer(expiredZeroKeyMaterial)
 	peer.timers.persistentKeepalive = peer.NewTimer(expiredPersistentKeepalive)
+}
+
+func (peer *Peer) timersStart() {
 	atomic.StoreUint32(&peer.timers.handshakeAttempts, 0)
 	peer.timers.sentLastMinuteHandshake.Set(false)
 	peer.timers.needAnotherKeepalive.Set(false)

device/tun.go

@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
+	"fmt"
 	"sync/atomic"
 
 	"golang.zx2c4.com/wireguard/tun"
@@ -14,43 +15,40 @@ import (
 const DefaultMTU = 1420
 
 func (device *Device) RoutineTUNEventReader() {
-	setUp := false
-	logDebug := device.log.Debug
-	logInfo := device.log.Info
-	logError := device.log.Error
-
-	logDebug.Println("Routine: event worker - started")
-	device.state.starting.Done()
+	device.log.Verbosef("Routine: event worker - started")
 
 	for event := range device.tun.device.Events() {
 		if event&tun.EventMTUUpdate != 0 {
 			mtu, err := device.tun.device.MTU()
-			old := atomic.LoadInt32(&device.tun.mtu)
 			if err != nil {
-				logError.Println("Failed to load updated MTU of device:", err)
-			} else if int(old) != mtu {
-				if mtu+MessageTransportSize > MaxMessageSize {
-					logInfo.Println("MTU updated:", mtu, "(too large)")
-				} else {
-					logInfo.Println("MTU updated:", mtu)
+				device.log.Errorf("Failed to load updated MTU of device: %v", err)
+				continue
 			}
-				atomic.StoreInt32(&device.tun.mtu, int32(mtu))
+			if mtu < 0 {
+				device.log.Errorf("MTU not updated to negative value: %v", mtu)
+				continue
+			}
+			var tooLarge string
+			if mtu > MaxContentSize {
+				tooLarge = fmt.Sprintf(" (too large, capped at %v)", MaxContentSize)
+				mtu = MaxContentSize
+			}
+			old := atomic.SwapInt32(&device.tun.mtu, int32(mtu))
+			if int(old) != mtu {
+				device.log.Verbosef("MTU updated: %v%s", mtu, tooLarge)
 			}
 		}
 
-		if event&tun.EventUp != 0 && !setUp {
-			logInfo.Println("Interface set up")
-			setUp = true
+		if event&tun.EventUp != 0 {
+			device.log.Verbosef("Interface up requested")
 			device.Up()
 		}
 
-		if event&tun.EventDown != 0 && setUp {
-			logInfo.Println("Interface set down")
-			setUp = false
+		if event&tun.EventDown != 0 {
+			device.log.Verbosef("Interface down requested")
 			device.Down()
 		}
 	}
 
-	logDebug.Println("Routine: event worker - stopped")
-	device.state.stopping.Done()
+	device.log.Verbosef("Routine: event worker - stopped")
 }

device/tun_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device

device/uapi.go

@@ -1,39 +1,75 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package device
 
 import (
 	"bufio"
+	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"net"
 	"strconv"
 	"strings"
+	"sync"
 	"sync/atomic"
 	"time"
 
+	"golang.zx2c4.com/wireguard/conn"
 	"golang.zx2c4.com/wireguard/ipc"
 )
 
 type IPCError struct {
-	int64
+	code int64 // error code
+	err  error // underlying/wrapped error
 }
 
 func (s IPCError) Error() string {
-	return fmt.Sprintf("IPC error: %d", s.int64)
+	return fmt.Sprintf("IPC error %d: %v", s.code, s.err)
+}
+
+func (s IPCError) Unwrap() error {
+	return s.err
 }
 
 func (s IPCError) ErrorCode() int64 {
-	return s.int64
+	return s.code
 }
 
-func (device *Device) IpcGetOperation(socket *bufio.Writer) *IPCError {
-	lines := make([]string, 0, 100)
-	send := func(line string) {
-		lines = append(lines, line)
+func ipcErrorf(code int64, msg string, args ...interface{}) *IPCError {
+	return &IPCError{code: code, err: fmt.Errorf(msg, args...)}
+}
+
+var byteBufferPool = &sync.Pool{
+	New: func() interface{} { return new(bytes.Buffer) },
+}
+
+// IpcGetOperation implements the WireGuard configuration protocol "get" operation.
+// See https://www.wireguard.com/xplatform/#configuration-protocol for details.
+func (device *Device) IpcGetOperation(w io.Writer) error {
+	device.ipcMutex.RLock()
+	defer device.ipcMutex.RUnlock()
+
+	buf := byteBufferPool.Get().(*bytes.Buffer)
+	buf.Reset()
+	defer byteBufferPool.Put(buf)
+	sendf := func(format string, args ...interface{}) {
+		fmt.Fprintf(buf, format, args...)
+		buf.WriteByte('\n')
+	}
+	keyf := func(prefix string, key *[32]byte) {
+		buf.Grow(len(key)*2 + 2 + len(prefix))
+		buf.WriteString(prefix)
+		buf.WriteByte('=')
+		const hex = "0123456789abcdef"
+		for i := 0; i < len(key); i++ {
+			buf.WriteByte(hex[key[i]>>4])
+			buf.WriteByte(hex[key[i]&0xf])
+		}
+		buf.WriteByte('\n')
 	}
 
 	func() {
@@ -52,15 +88,15 @@ func (device *Device) IpcGetOperation(socket *bufio.Writer) *IPCError {
 		// serialize device related values
 
 		if !device.staticIdentity.privateKey.IsZero() {
-			send("private_key=" + device.staticIdentity.privateKey.ToHex())
+			keyf("private_key", (*[32]byte)(&device.staticIdentity.privateKey))
 		}
 
 		if device.net.port != 0 {
-			send(fmt.Sprintf("listen_port=%d", device.net.port))
+			sendf("listen_port=%d", device.net.port)
 		}
 
 		if device.net.fwmark != 0 {
-			send(fmt.Sprintf("fwmark=%d", device.net.fwmark))
+			sendf("fwmark=%d", device.net.fwmark)
 		}
 
 		// serialize each peer state
@@ -69,336 +105,308 @@ func (device *Device) IpcGetOperation(socket *bufio.Writer) *IPCError {
 			peer.RLock()
 			defer peer.RUnlock()
 
-			send("public_key=" + peer.handshake.remoteStatic.ToHex())
-			send("preshared_key=" + peer.handshake.presharedKey.ToHex())
-			send("protocol_version=1")
+			keyf("public_key", (*[32]byte)(&peer.handshake.remoteStatic))
+			keyf("preshared_key", (*[32]byte)(&peer.handshake.presharedKey))
+			sendf("protocol_version=1")
 			if peer.endpoint != nil {
-				send("endpoint=" + peer.endpoint.DstToString())
+				sendf("endpoint=%s", peer.endpoint.DstToString())
 			}
 
 			nano := atomic.LoadInt64(&peer.stats.lastHandshakeNano)
 			secs := nano / time.Second.Nanoseconds()
 			nano %= time.Second.Nanoseconds()
 
-			send(fmt.Sprintf("last_handshake_time_sec=%d", secs))
-			send(fmt.Sprintf("last_handshake_time_nsec=%d", nano))
-			send(fmt.Sprintf("tx_bytes=%d", atomic.LoadUint64(&peer.stats.txBytes)))
-			send(fmt.Sprintf("rx_bytes=%d", atomic.LoadUint64(&peer.stats.rxBytes)))
-			send(fmt.Sprintf("persistent_keepalive_interval=%d", peer.persistentKeepaliveInterval))
-
-			for _, ip := range device.allowedips.EntriesForPeer(peer) {
-				send("allowed_ip=" + ip.String())
-			}
+			sendf("last_handshake_time_sec=%d", secs)
+			sendf("last_handshake_time_nsec=%d", nano)
+			sendf("tx_bytes=%d", atomic.LoadUint64(&peer.stats.txBytes))
+			sendf("rx_bytes=%d", atomic.LoadUint64(&peer.stats.rxBytes))
+			sendf("persistent_keepalive_interval=%d", atomic.LoadUint32(&peer.persistentKeepaliveInterval))
 
+			device.allowedips.EntriesForPeer(peer, func(ip net.IP, cidr uint) bool {
+				sendf("allowed_ip=%s/%d", ip.String(), cidr)
+				return true
+			})
 		}
 	}()
 
 	// send lines (does not require resource locks)
-
-	for _, line := range lines {
-		_, err := socket.WriteString(line + "\n")
-		if err != nil {
-			return &IPCError{ipc.IpcErrorIO}
-		}
+	if _, err := w.Write(buf.Bytes()); err != nil {
+		return ipcErrorf(ipc.IpcErrorIO, "failed to write output: %w", err)
 	}
 
 	return nil
 }
 
-func (device *Device) IpcSetOperation(socket *bufio.Reader) *IPCError {
-	scanner := bufio.NewScanner(socket)
-	logError := device.log.Error
-	logDebug := device.log.Debug
+// IpcSetOperation implements the WireGuard configuration protocol "set" operation.
+// See https://www.wireguard.com/xplatform/#configuration-protocol for details.
+func (device *Device) IpcSetOperation(r io.Reader) (err error) {
+	device.ipcMutex.Lock()
+	defer device.ipcMutex.Unlock()
 
-	var peer *Peer
+	defer func() {
+		if err != nil {
+			device.log.Errorf("%v", err)
+		}
+	}()
 
-	dummy := false
-	createdNewPeer := false
+	peer := new(ipcSetPeer)
 	deviceConfig := true
 
+	scanner := bufio.NewScanner(r)
 	for scanner.Scan() {
-
-		// parse line
-
 		line := scanner.Text()
 		if line == "" {
+			// Blank line means terminate operation.
 			return nil
 		}
 		parts := strings.Split(line, "=")
 		if len(parts) != 2 {
-			return &IPCError{ipc.IpcErrorProtocol}
+			return ipcErrorf(ipc.IpcErrorProtocol, "failed to parse line %q, found %d =-separated parts, want 2", line, len(parts))
 		}
 		key := parts[0]
 		value := parts[1]
 
-		/* device configuration */
-
+		if key == "public_key" {
 			if deviceConfig {
+				deviceConfig = false
+			}
+			peer.handlePostConfig()
+			// Load/create the peer we are now configuring.
+			err := device.handlePublicKeyLine(peer, value)
+			if err != nil {
+				return err
+			}
+			continue
+		}
 
+		var err error
+		if deviceConfig {
+			err = device.handleDeviceLine(key, value)
+		} else {
+			err = device.handlePeerLine(peer, key, value)
+		}
+		if err != nil {
+			return err
+		}
+	}
+	peer.handlePostConfig()
+
+	if err := scanner.Err(); err != nil {
+		return ipcErrorf(ipc.IpcErrorIO, "failed to read input: %w", err)
+	}
+	return nil
+}
+
+func (device *Device) handleDeviceLine(key, value string) error {
 	switch key {
 	case "private_key":
 		var sk NoisePrivateKey
-				err := sk.FromHex(value)
+		err := sk.FromMaybeZeroHex(value)
 		if err != nil {
-					logError.Println("Failed to set private_key:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set private_key: %w", err)
 		}
-				logDebug.Println("UAPI: Updating private key")
+		device.log.Verbosef("UAPI: Updating private key")
 		device.SetPrivateKey(sk)
 
 	case "listen_port":
-
-				// parse port number
-
 		port, err := strconv.ParseUint(value, 10, 16)
 		if err != nil {
-					logError.Println("Failed to parse listen_port:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to parse listen_port: %w", err)
 		}
 
 		// update port and rebind
-
-				logDebug.Println("UAPI: Updating listen port")
+		device.log.Verbosef("UAPI: Updating listen port")
 
 		device.net.Lock()
 		device.net.port = uint16(port)
 		device.net.Unlock()
 
 		if err := device.BindUpdate(); err != nil {
-					logError.Println("Failed to set listen_port:", err)
-					return &IPCError{ipc.IpcErrorPortInUse}
+			return ipcErrorf(ipc.IpcErrorPortInUse, "failed to set listen_port: %w", err)
 		}
 
 	case "fwmark":
-
-				// parse fwmark field
-
-				fwmark, err := func() (uint32, error) {
-					if value == "" {
-						return 0, nil
-					}
 		mark, err := strconv.ParseUint(value, 10, 32)
-					return uint32(mark), err
-				}()
-
 		if err != nil {
-					logError.Println("Invalid fwmark", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "invalid fwmark: %w", err)
 		}
 
-				logDebug.Println("UAPI: Updating fwmark")
-
-				if err := device.BindSetMark(uint32(fwmark)); err != nil {
-					logError.Println("Failed to update fwmark:", err)
-					return &IPCError{ipc.IpcErrorPortInUse}
+		device.log.Verbosef("UAPI: Updating fwmark")
+		if err := device.BindSetMark(uint32(mark)); err != nil {
+			return ipcErrorf(ipc.IpcErrorPortInUse, "failed to update fwmark: %w", err)
 		}
 
-			case "public_key":
-				// switch to peer configuration
-				logDebug.Println("UAPI: Transition to peer configuration")
-				deviceConfig = false
-
 	case "replace_peers":
 		if value != "true" {
-					logError.Println("Failed to set replace_peers, invalid value:", value)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set replace_peers, invalid value: %v", value)
 		}
-				logDebug.Println("UAPI: Removing all peers")
+		device.log.Verbosef("UAPI: Removing all peers")
 		device.RemoveAllPeers()
 
 	default:
-				logError.Println("Invalid UAPI device key:", key)
-				return &IPCError{ipc.IpcErrorInvalid}
-			}
+		return ipcErrorf(ipc.IpcErrorInvalid, "invalid UAPI device key: %v", key)
 	}
 
-		/* peer configuration */
+	return nil
+}
 
-		if !deviceConfig {
+// An ipcSetPeer is the current state of an IPC set operation on a peer.
+type ipcSetPeer struct {
+	*Peer        // Peer is the current peer being operated on
+	dummy   bool // dummy reports whether this peer is a temporary, placeholder peer
+	created bool // new reports whether this is a newly created peer
+}
 
-			switch key {
+func (peer *ipcSetPeer) handlePostConfig() {
+	if peer.Peer != nil && !peer.dummy && peer.Peer.device.isUp() {
+		peer.SendStagedPackets()
+	}
+}
 
-			case "public_key":
+func (device *Device) handlePublicKeyLine(peer *ipcSetPeer, value string) error {
+	// Load/create the peer we are configuring.
 	var publicKey NoisePublicKey
 	err := publicKey.FromHex(value)
 	if err != nil {
-					logError.Println("Failed to get peer by public key:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+		return ipcErrorf(ipc.IpcErrorInvalid, "failed to get peer by public key: %w", err)
 	}
 
-				// ignore peer with public key of device
-
+	// Ignore peer with the same public key as this device.
 	device.staticIdentity.RLock()
-				dummy = device.staticIdentity.publicKey.Equals(publicKey)
+	peer.dummy = device.staticIdentity.publicKey.Equals(publicKey)
 	device.staticIdentity.RUnlock()
 
-				if dummy {
-					peer = &Peer{}
+	if peer.dummy {
+		peer.Peer = &Peer{}
 	} else {
-					peer = device.LookupPeer(publicKey)
+		peer.Peer = device.LookupPeer(publicKey)
 	}
 
-				createdNewPeer = peer == nil
-				if createdNewPeer {
-					peer, err = device.NewPeer(publicKey)
+	peer.created = peer.Peer == nil
+	if peer.created {
+		peer.Peer, err = device.NewPeer(publicKey)
 		if err != nil {
-						logError.Println("Failed to create new peer:", err)
-						return &IPCError{ipc.IpcErrorInvalid}
-					}
-					if peer == nil {
-						dummy = true
-						peer = &Peer{}
-					} else {
-						logDebug.Println(peer, "- UAPI: Created")
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to create new peer: %w", err)
 		}
+		device.log.Verbosef("%v - UAPI: Created", peer.Peer)
 	}
+	return nil
+}
 
+func (device *Device) handlePeerLine(peer *ipcSetPeer, key, value string) error {
+	switch key {
 	case "update_only":
-
 		// allow disabling of creation
-
 		if value != "true" {
-					logError.Println("Failed to set update only, invalid value:", value)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set update only, invalid value: %v", value)
 		}
-				if createdNewPeer && !dummy {
+		if peer.created && !peer.dummy {
 			device.RemovePeer(peer.handshake.remoteStatic)
-					peer = &Peer{}
-					dummy = true
+			peer.Peer = &Peer{}
+			peer.dummy = true
 		}
 
 	case "remove":
-
 		// remove currently selected peer from device
-
 		if value != "true" {
-					logError.Println("Failed to set remove, invalid value:", value)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set remove, invalid value: %v", value)
 		}
-				if !dummy {
-					logDebug.Println(peer, "- UAPI: Removing")
+		if !peer.dummy {
+			device.log.Verbosef("%v - UAPI: Removing", peer.Peer)
 			device.RemovePeer(peer.handshake.remoteStatic)
 		}
-				peer = &Peer{}
-				dummy = true
+		peer.Peer = &Peer{}
+		peer.dummy = true
 
 	case "preshared_key":
-
-				// update PSK
-
-				logDebug.Println(peer, "- UAPI: Updating preshared key")
+		device.log.Verbosef("%v - UAPI: Updating preshared key", peer.Peer)
 
 		peer.handshake.mutex.Lock()
 		err := peer.handshake.presharedKey.FromHex(value)
 		peer.handshake.mutex.Unlock()
 
 		if err != nil {
-					logError.Println("Failed to set preshared key:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set preshared key: %w", err)
 		}
 
 	case "endpoint":
-
-				// set endpoint destination
-
-				logDebug.Println(peer, "- UAPI: Updating endpoint")
-
-				err := func() error {
+		device.log.Verbosef("%v - UAPI: Updating endpoint", peer.Peer)
+		endpoint, err := conn.CreateEndpoint(value)
+		if err != nil {
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set endpoint %v: %w", value, err)
+		}
 		peer.Lock()
 		defer peer.Unlock()
-					endpoint, err := CreateEndpoint(value)
-					if err != nil {
-						return err
-					}
 		peer.endpoint = endpoint
-					return nil
-				}()
-
-				if err != nil {
-					logError.Println("Failed to set endpoint:", err, ":", value)
-					return &IPCError{ipc.IpcErrorInvalid}
-				}
 
 	case "persistent_keepalive_interval":
-
-				// update persistent keepalive interval
-
-				logDebug.Println(peer, "- UAPI: Updating persistent keepalive interval")
+		device.log.Verbosef("%v - UAPI: Updating persistent keepalive interval", peer.Peer)
 
 		secs, err := strconv.ParseUint(value, 10, 16)
 		if err != nil {
-					logError.Println("Failed to set persistent keepalive interval:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set persistent keepalive interval: %w", err)
 		}
 
-				old := peer.persistentKeepaliveInterval
-				peer.persistentKeepaliveInterval = uint16(secs)
-
-				// send immediate keepalive if we're turning it on and before it wasn't on
+		old := atomic.SwapUint32(&peer.persistentKeepaliveInterval, uint32(secs))
 
+		// Send immediate keepalive if we're turning it on and before it wasn't on.
 		if old == 0 && secs != 0 {
 			if err != nil {
-						logError.Println("Failed to get tun device status:", err)
-						return &IPCError{ipc.IpcErrorIO}
+				return ipcErrorf(ipc.IpcErrorIO, "failed to get tun device status: %w", err)
 			}
-					if device.isUp.Get() && !dummy {
+			if device.isUp() && !peer.dummy {
 				peer.SendKeepalive()
 			}
 		}
 
 	case "replace_allowed_ips":
-
-				logDebug.Println(peer, "- UAPI: Removing all allowedips")
-
+		device.log.Verbosef("%v - UAPI: Removing all allowedips", peer.Peer)
 		if value != "true" {
-					logError.Println("Failed to replace allowedips, invalid value:", value)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to replace allowedips, invalid value: %v", value)
 		}
-
-				if dummy {
-					continue
+		if peer.dummy {
+			return nil
 		}
-
-				device.allowedips.RemoveByPeer(peer)
+		device.allowedips.RemoveByPeer(peer.Peer)
 
 	case "allowed_ip":
-
-				logDebug.Println(peer, "- UAPI: Adding allowedip")
+		device.log.Verbosef("%v - UAPI: Adding allowedip", peer.Peer)
 
 		_, network, err := net.ParseCIDR(value)
 		if err != nil {
-					logError.Println("Failed to set allowed ip:", err)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set allowed ip: %w", err)
 		}
-
-				if dummy {
-					continue
+		if peer.dummy {
+			return nil
 		}
-
 		ones, _ := network.Mask.Size()
-				device.allowedips.Insert(network.IP, uint(ones), peer)
+		device.allowedips.Insert(network.IP, uint(ones), peer.Peer)
 
 	case "protocol_version":
-
 		if value != "1" {
-					logError.Println("Invalid protocol version:", value)
-					return &IPCError{ipc.IpcErrorInvalid}
+			return ipcErrorf(ipc.IpcErrorInvalid, "invalid protocol version: %v", value)
 		}
 
 	default:
-				logError.Println("Invalid UAPI peer key:", key)
-				return &IPCError{ipc.IpcErrorInvalid}
-			}
-		}
+		return ipcErrorf(ipc.IpcErrorInvalid, "invalid UAPI peer key: %v", key)
 	}
 
 	return nil
 }
 
+func (device *Device) IpcGet() (string, error) {
+	buf := new(strings.Builder)
+	if err := device.IpcGetOperation(buf); err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}
+
+func (device *Device) IpcSet(uapiConf string) error {
+	return device.IpcSetOperation(strings.NewReader(uapiConf))
+}
+
 func (device *Device) IpcHandle(socket net.Conn) {
-
-	// create buffered read/writer
-
 	defer socket.Close()
 
 	buffered := func(s io.ReadWriter) *bufio.ReadWriter {
@@ -407,35 +415,44 @@ func (device *Device) IpcHandle(socket net.Conn) {
 		return bufio.NewReadWriter(reader, writer)
 	}(socket)
 
-	defer buffered.Flush()
-
+	for {
 		op, err := buffered.ReadString('\n')
 		if err != nil {
 			return
 		}
 
 		// handle operation
-
-	var status *IPCError
-
 		switch op {
 		case "set=1\n":
-		status = device.IpcSetOperation(buffered.Reader)
-
+			err = device.IpcSetOperation(buffered.Reader)
 		case "get=1\n":
-		status = device.IpcGetOperation(buffered.Writer)
-
+			var nextByte byte
+			nextByte, err = buffered.ReadByte()
+			if err != nil {
+				return
+			}
+			if nextByte != '\n' {
+				err = ipcErrorf(ipc.IpcErrorInvalid, "trailing character in UAPI get: %q", nextByte)
+				break
+			}
+			err = device.IpcGetOperation(buffered.Writer)
 		default:
-		device.log.Error.Println("Invalid UAPI operation:", op)
+			device.log.Errorf("invalid UAPI operation: %v", op)
 			return
 		}
 
 		// write status
-
+		var status *IPCError
+		if err != nil && !errors.As(err, &status) {
+			// shouldn't happen
+			status = ipcErrorf(ipc.IpcErrorUnknown, "other UAPI error: %w", err)
+		}
 		if status != nil {
-		device.log.Error.Println(status)
+			device.log.Errorf("%v", status)
 			fmt.Fprintf(buffered, "errno=%d\n\n", status.ErrorCode())
 		} else {
 			fmt.Fprintf(buffered, "errno=0\n\n")
 		}
+		buffered.Flush()
+	}
 }

device/version.go

@@ -1,3 +0,0 @@
-package device
-
-const WireGuardGoVersion = "0.0.20200121"

go.mod

@@ -1,10 +1,9 @@
 module golang.zx2c4.com/wireguard
 
-go 1.12
+go 1.15
 
 require (
-	golang.org/x/crypto v0.0.0-20191002192127-34f69633bfdc
-	golang.org/x/net v0.0.0-20191003171128-d98b1b443823
-	golang.org/x/sys v0.0.0-20191003212358-c178f38b412c
-	golang.org/x/text v0.3.2
+	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad
+	golang.org/x/net v0.0.0-20201224014010-6772e930b67b
+	golang.org/x/sys v0.0.0-20210105210732-16f7687f5001
 )

go.sum

@@ -1,14 +1,17 @@
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20191002192127-34f69633bfdc h1:c0o/qxkaO2LF5t6fQrT4b5hzyggAkLLlCUjqfRxd8Q4=
-golang.org/x/crypto v0.0.0-20191002192127-34f69633bfdc/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad h1:DN0cp81fZ3njFcrLCytUHRSUkqBjfTo4Tx9RJTWs0EY=
+golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20191003171128-d98b1b443823 h1:Ypyv6BNJh07T1pUSrehkLemqPKXhus2MkfktJ91kRh4=
-golang.org/x/net v0.0.0-20191003171128-d98b1b443823/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20201224014010-6772e930b67b h1:iFwSg7t5GZmB/Q5TjiEAsdoLDrdJRC1RiF2WhuV29Qw=
+golang.org/x/net v0.0.0-20201224014010-6772e930b67b/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20191003212358-c178f38b412c h1:6Zx7DRlKXf79yfxuQ/7GqV3w2y7aDsk6bGg0MzF5RVU=
-golang.org/x/sys v0.0.0-20191003212358-c178f38b412c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210105210732-16f7687f5001 h1:/dSxr6gT0FNI1MO5WLJo8mTmItROeOKTkDn+7OwWBos=
+golang.org/x/sys v0.0.0-20210105210732-16f7687f5001/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
-golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e h1:FDhOuMEY4JVRztM/gsbk+IKUQ8kj74bxZrgw87eMMVc=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

ipc/uapi_bsd.go

@@ -2,32 +2,20 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ipc
 
 import (
 	"errors"
-	"fmt"
 	"net"
 	"os"
-	"path"
 	"unsafe"
 
 	"golang.org/x/sys/unix"
 )
 
-var socketDirectory = "/var/run/wireguard"
-
-const (
-	IpcErrorIO        = -int64(unix.EIO)
-	IpcErrorProtocol  = -int64(unix.EPROTO)
-	IpcErrorInvalid   = -int64(unix.EINVAL)
-	IpcErrorPortInUse = -int64(unix.EADDRINUSE)
-	socketName        = "%s.sock"
-)
-
 type UAPIListener struct {
 	listener net.Listener // unix socket listener
 	connNew  chan net.Conn
@@ -84,10 +72,7 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 		unixListener.SetUnlinkOnClose(true)
 	}
 
-	socketPath := path.Join(
-		socketDirectory,
-		fmt.Sprintf(socketName, name),
-	)
+	socketPath := sockPath(name)
 
 	// watch for deletion of socket
 
@@ -146,58 +131,3 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 
 	return uapi, nil
 }
-
-func UAPIOpen(name string) (*os.File, error) {
-
-	// check if path exist
-
-	err := os.MkdirAll(socketDirectory, 0755)
-	if err != nil && !os.IsExist(err) {
-		return nil, err
-	}
-
-	// open UNIX socket
-
-	socketPath := path.Join(
-		socketDirectory,
-		fmt.Sprintf(socketName, name),
-	)
-
-	addr, err := net.ResolveUnixAddr("unix", socketPath)
-	if err != nil {
-		return nil, err
-	}
-
-	oldUmask := unix.Umask(0077)
-	listener, err := func() (*net.UnixListener, error) {
-
-		// initial connection attempt
-
-		listener, err := net.ListenUnix("unix", addr)
-		if err == nil {
-			return listener, nil
-		}
-
-		// check if socket already active
-
-		_, err = net.Dial("unix", socketPath)
-		if err == nil {
-			return nil, errors.New("unix socket in use")
-		}
-
-		// cleanup & attempt again
-
-		err = os.Remove(socketPath)
-		if err != nil {
-			return nil, err
-		}
-		return net.ListenUnix("unix", addr)
-	}()
-	unix.Umask(oldUmask)
-
-	if err != nil {
-		return nil, err
-	}
-
-	return listener.File()
-}

ipc/uapi_linux.go

@@ -1,31 +1,18 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ipc
 
 import (
-	"errors"
-	"fmt"
 	"net"
 	"os"
-	"path"
 
 	"golang.org/x/sys/unix"
 	"golang.zx2c4.com/wireguard/rwcancel"
 )
 
-var socketDirectory = "/var/run/wireguard"
-
-const (
-	IpcErrorIO        = -int64(unix.EIO)
-	IpcErrorProtocol  = -int64(unix.EPROTO)
-	IpcErrorInvalid   = -int64(unix.EINVAL)
-	IpcErrorPortInUse = -int64(unix.EADDRINUSE)
-	socketName        = "%s.sock"
-)
-
 type UAPIListener struct {
 	listener        net.Listener // unix socket listener
 	connNew         chan net.Conn
@@ -84,10 +71,7 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 
 	// watch for deletion of socket
 
-	socketPath := path.Join(
-		socketDirectory,
-		fmt.Sprintf(socketName, name),
-	)
+	socketPath := sockPath(name)
 
 	uapi.inotifyFd, err = unix.InotifyInit()
 	if err != nil {
@@ -115,6 +99,7 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 	go func(l *UAPIListener) {
 		var buff [0]byte
 		for {
+			defer uapi.inotifyRWCancel.Close()
 			// start with lstat to avoid race condition
 			if _, err := os.Lstat(socketPath); os.IsNotExist(err) {
 				l.connErr <- err
@@ -143,58 +128,3 @@ func UAPIListen(name string, file *os.File) (net.Listener, error) {
 
 	return uapi, nil
 }
-
-func UAPIOpen(name string) (*os.File, error) {
-
-	// check if path exist
-
-	err := os.MkdirAll(socketDirectory, 0755)
-	if err != nil && !os.IsExist(err) {
-		return nil, err
-	}
-
-	// open UNIX socket
-
-	socketPath := path.Join(
-		socketDirectory,
-		fmt.Sprintf(socketName, name),
-	)
-
-	addr, err := net.ResolveUnixAddr("unix", socketPath)
-	if err != nil {
-		return nil, err
-	}
-
-	oldUmask := unix.Umask(0077)
-	listener, err := func() (*net.UnixListener, error) {
-
-		// initial connection attempt
-
-		listener, err := net.ListenUnix("unix", addr)
-		if err == nil {
-			return listener, nil
-		}
-
-		// check if socket already active
-
-		_, err = net.Dial("unix", socketPath)
-		if err == nil {
-			return nil, errors.New("unix socket in use")
-		}
-
-		// cleanup & attempt again
-
-		err = os.Remove(socketPath)
-		if err != nil {
-			return nil, err
-		}
-		return net.ListenUnix("unix", addr)
-	}()
-	unix.Umask(oldUmask)
-
-	if err != nil {
-		return nil, err
-	}
-
-	return listener.File()
-}

ipc/uapi_unix.go

@@ -0,0 +1,66 @@
+// +build linux darwin freebsd openbsd
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package ipc
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+const (
+	IpcErrorIO        = -int64(unix.EIO)
+	IpcErrorProtocol  = -int64(unix.EPROTO)
+	IpcErrorInvalid   = -int64(unix.EINVAL)
+	IpcErrorPortInUse = -int64(unix.EADDRINUSE)
+	IpcErrorUnknown   = -55 // ENOANO
+)
+
+// socketDirectory is variable because it is modified by a linker
+// flag in wireguard-android.
+var socketDirectory = "/var/run/wireguard"
+
+func sockPath(iface string) string {
+	return fmt.Sprintf("%s/%s.sock", socketDirectory, iface)
+}
+
+func UAPIOpen(name string) (*os.File, error) {
+	if err := os.MkdirAll(socketDirectory, 0755); err != nil {
+		return nil, err
+	}
+
+	socketPath := sockPath(name)
+	addr, err := net.ResolveUnixAddr("unix", socketPath)
+	if err != nil {
+		return nil, err
+	}
+
+	oldUmask := unix.Umask(0077)
+	defer unix.Umask(oldUmask)
+
+	listener, err := net.ListenUnix("unix", addr)
+	if err == nil {
+		return listener.File()
+	}
+
+	// Test socket, if not in use cleanup and try again.
+	if _, err := net.Dial("unix", socketPath); err == nil {
+		return nil, errors.New("unix socket in use")
+	}
+	if err := os.Remove(socketPath); err != nil {
+		return nil, err
+	}
+	listener, err = net.ListenUnix("unix", addr)
+	if err != nil {
+		return nil, err
+	}
+	return listener.File()
+}

ipc/uapi_windows.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ipc
@@ -19,6 +19,7 @@ const (
 	IpcErrorProtocol  = -int64(71)
 	IpcErrorInvalid   = -int64(22)
 	IpcErrorPortInUse = -int64(98)
+	IpcErrorUnknown   = -int64(55)
 )
 
 type UAPIListener struct {

ipc/winpipe/file.go

@@ -3,7 +3,7 @@
 /* SPDX-License-Identifier: MIT
  *
  * Copyright (C) 2005 Microsoft
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 package winpipe
 

ipc/winpipe/mksyscall.go

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: MIT
  *
  * Copyright (C) 2005 Microsoft
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package winpipe

ipc/winpipe/pipe.go

@@ -3,7 +3,7 @@
 /* SPDX-License-Identifier: MIT
  *
  * Copyright (C) 2005 Microsoft
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package winpipe

main.go

@@ -2,7 +2,7 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package main
@@ -41,23 +41,21 @@ func warning() {
 		return
 	}
 
-	fmt.Fprintln(os.Stderr, "WARNING WARNING WARNING WARNING WARNING WARNING WARNING")
-	fmt.Fprintln(os.Stderr, "W                                                     G")
-	fmt.Fprintln(os.Stderr, "W   You are running this software on a Linux kernel,  G")
-	fmt.Fprintln(os.Stderr, "W   which is probably unnecessary and misguided. This G")
-	fmt.Fprintln(os.Stderr, "W   is because the Linux kernel has built-in first    G")
-	fmt.Fprintln(os.Stderr, "W   class support for WireGuard, and this support is  G")
-	fmt.Fprintln(os.Stderr, "W   much more refined than this slower userspace      G")
-	fmt.Fprintln(os.Stderr, "W   implementation. For more information on           G")
-	fmt.Fprintln(os.Stderr, "W   installing the kernel module, please visit:       G")
-	fmt.Fprintln(os.Stderr, "W           https://www.wireguard.com/install         G")
-	fmt.Fprintln(os.Stderr, "W                                                     G")
-	fmt.Fprintln(os.Stderr, "WARNING WARNING WARNING WARNING WARNING WARNING WARNING")
+	fmt.Fprintln(os.Stderr, "┌───────────────────────────────────────────────────┐")
+	fmt.Fprintln(os.Stderr, "│                                                   │")
+	fmt.Fprintln(os.Stderr, "│   Running this software on Linux is unnecessary,  │")
+	fmt.Fprintln(os.Stderr, "│   because the Linux kernel has built-in first     │")
+	fmt.Fprintln(os.Stderr, "│   class support for WireGuard, which will be      │")
+	fmt.Fprintln(os.Stderr, "│   faster, slicker, and better integrated. For     │")
+	fmt.Fprintln(os.Stderr, "│   information on installing the kernel module,    │")
+	fmt.Fprintln(os.Stderr, "│   please visit: <https://wireguard.com/install>.  │")
+	fmt.Fprintln(os.Stderr, "│                                                   │")
+	fmt.Fprintln(os.Stderr, "└───────────────────────────────────────────────────┘")
 }
 
 func main() {
 	if len(os.Args) == 2 && os.Args[1] == "--version" {
-		fmt.Printf("wireguard-go v%s\n\nUserspace WireGuard daemon for %s-%s.\nInformation available at https://www.wireguard.com.\nCopyright (C) Jason A. Donenfeld <Jason@zx2c4.com>.\n", device.WireGuardGoVersion, runtime.GOOS, runtime.GOARCH)
+		fmt.Printf("wireguard-go v%s\n\nUserspace WireGuard daemon for %s-%s.\nInformation available at https://www.wireguard.com.\nCopyright (C) Jason A. Donenfeld <Jason@zx2c4.com>.\n", Version, runtime.GOOS, runtime.GOARCH)
 		return
 	}
 
@@ -97,16 +95,14 @@ func main() {
 
 	logLevel := func() int {
 		switch os.Getenv("LOG_LEVEL") {
-		case "debug":
-			return device.LogLevelDebug
-		case "info":
-			return device.LogLevelInfo
+		case "verbose", "debug":
+			return device.LogLevelVerbose
 		case "error":
 			return device.LogLevelError
 		case "silent":
 			return device.LogLevelSilent
 		}
-		return device.LogLevelInfo
+		return device.LogLevelError
 	}()
 
 	// open TUN device (or use supplied fd)
@@ -145,12 +141,10 @@ func main() {
 		fmt.Sprintf("(%s) ", interfaceName),
 	)
 
-	logger.Info.Println("Starting wireguard-go version", device.WireGuardGoVersion)
-
-	logger.Debug.Println("Debug log enabled")
+	logger.Verbosef("Starting wireguard-go version %s", Version)
 
 	if err != nil {
-		logger.Error.Println("Failed to create TUN device:", err)
+		logger.Errorf("Failed to create TUN device: %v", err)
 		os.Exit(ExitSetupFailed)
 	}
 
@@ -173,7 +167,7 @@ func main() {
 	}()
 
 	if err != nil {
-		logger.Error.Println("UAPI listen error:", err)
+		logger.Errorf("UAPI listen error: %v", err)
 		os.Exit(ExitSetupFailed)
 		return
 	}
@@ -208,7 +202,7 @@ func main() {
 
 		path, err := os.Executable()
 		if err != nil {
-			logger.Error.Println("Failed to determine executable:", err)
+			logger.Errorf("Failed to determine executable: %v", err)
 			os.Exit(ExitSetupFailed)
 		}
 
@@ -218,7 +212,7 @@ func main() {
 			attr,
 		)
 		if err != nil {
-			logger.Error.Println("Failed to daemonize:", err)
+			logger.Errorf("Failed to daemonize: %v", err)
 			os.Exit(ExitSetupFailed)
 		}
 		process.Release()
@@ -227,14 +221,14 @@ func main() {
 
 	device := device.NewDevice(tun, logger)
 
-	logger.Info.Println("Device started")
+	logger.Verbosef("Device started")
 
 	errs := make(chan error)
 	term := make(chan os.Signal, 1)
 
 	uapi, err := ipc.UAPIListen(interfaceName, fileUAPI)
 	if err != nil {
-		logger.Error.Println("Failed to listen on uapi socket:", err)
+		logger.Errorf("Failed to listen on uapi socket: %v", err)
 		os.Exit(ExitSetupFailed)
 	}
 
@@ -249,7 +243,7 @@ func main() {
 		}
 	}()
 
-	logger.Info.Println("UAPI listener started")
+	logger.Verbosef("UAPI listener started")
 
 	// wait for program to terminate
 
@@ -267,5 +261,5 @@ func main() {
 	uapi.Close()
 	device.Close()
 
-	logger.Info.Println("Shutting down")
+	logger.Verbosef("Shutting down")
 }

main_windows.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package main
@@ -31,11 +31,10 @@ func main() {
 	fmt.Fprintln(os.Stderr, "Warning: this is a test program for Windows, mainly used for debugging this Go package. For a real WireGuard for Windows client, the repo you want is <https://git.zx2c4.com/wireguard-windows/>, which includes this code as a module.")
 
 	logger := device.NewLogger(
-		device.LogLevelDebug,
+		device.LogLevelVerbose,
 		fmt.Sprintf("(%s) ", interfaceName),
 	)
-	logger.Info.Println("Starting wireguard-go version", device.WireGuardGoVersion)
-	logger.Debug.Println("Debug log enabled")
+	logger.Verbosef("Starting wireguard-go version %s", Version)
 
 	tun, err := tun.CreateTUN(interfaceName, 0)
 	if err == nil {
@@ -44,17 +43,21 @@ func main() {
 			interfaceName = realInterfaceName
 		}
 	} else {
-		logger.Error.Println("Failed to create TUN device:", err)
+		logger.Errorf("Failed to create TUN device: %v", err)
 		os.Exit(ExitSetupFailed)
 	}
 
 	device := device.NewDevice(tun, logger)
-	device.Up()
-	logger.Info.Println("Device started")
+	err = device.Up()
+	if err != nil {
+		logger.Errorf("Failed to bring up device: %v", err)
+		os.Exit(ExitSetupFailed)
+	}
+	logger.Verbosef("Device started")
 
 	uapi, err := ipc.UAPIListen(interfaceName)
 	if err != nil {
-		logger.Error.Println("Failed to listen on uapi socket:", err)
+		logger.Errorf("Failed to listen on uapi socket: %v", err)
 		os.Exit(ExitSetupFailed)
 	}
 
@@ -71,7 +74,7 @@ func main() {
 			go device.IpcHandle(conn)
 		}
 	}()
-	logger.Info.Println("UAPI listener started")
+	logger.Verbosef("UAPI listener started")
 
 	// wait for program to terminate
 
@@ -90,5 +93,5 @@ func main() {
 	uapi.Close()
 	device.Close()
 
-	logger.Info.Println("Shutting down")
+	logger.Verbosef("Shutting down")
 }

ratelimiter/ratelimiter.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ratelimiter
@@ -20,21 +20,23 @@ const (
 )
 
 type RatelimiterEntry struct {
-	sync.Mutex
+	mu       sync.Mutex
 	lastTime time.Time
 	tokens   int64
 }
 
 type Ratelimiter struct {
-	sync.RWMutex
-	stopReset chan struct{}
+	mu      sync.RWMutex
+	timeNow func() time.Time
+
+	stopReset chan struct{} // send to reset, close to stop
 	tableIPv4 map[[net.IPv4len]byte]*RatelimiterEntry
 	tableIPv6 map[[net.IPv6len]byte]*RatelimiterEntry
 }
 
 func (rate *Ratelimiter) Close() {
-	rate.Lock()
-	defer rate.Unlock()
+	rate.mu.Lock()
+	defer rate.mu.Unlock()
 
 	if rate.stopReset != nil {
 		close(rate.stopReset)
@@ -42,11 +44,14 @@ func (rate *Ratelimiter) Close() {
 }
 
 func (rate *Ratelimiter) Init() {
-	rate.Lock()
-	defer rate.Unlock()
+	rate.mu.Lock()
+	defer rate.mu.Unlock()
+
+	if rate.timeNow == nil {
+		rate.timeNow = time.Now
+	}
 
 	// stop any ongoing garbage collection routine
-
 	if rate.stopReset != nil {
 		close(rate.stopReset)
 	}
@@ -55,48 +60,50 @@ func (rate *Ratelimiter) Init() {
 	rate.tableIPv4 = make(map[[net.IPv4len]byte]*RatelimiterEntry)
 	rate.tableIPv6 = make(map[[net.IPv6len]byte]*RatelimiterEntry)
 
-	// start garbage collection routine
+	stopReset := rate.stopReset // store in case Init is called again.
 
+	// Start garbage collection routine.
 	go func() {
 		ticker := time.NewTicker(time.Second)
 		ticker.Stop()
 		for {
 			select {
-			case _, ok := <-rate.stopReset:
+			case _, ok := <-stopReset:
 				ticker.Stop()
-				if ok {
-					ticker = time.NewTicker(time.Second)
-				} else {
+				if !ok {
 					return
 				}
+				ticker = time.NewTicker(time.Second)
 			case <-ticker.C:
-				func() {
-					rate.Lock()
-					defer rate.Unlock()
+				if rate.cleanup() {
+					ticker.Stop()
+				}
+			}
+		}
+	}()
+}
+
+func (rate *Ratelimiter) cleanup() (empty bool) {
+	rate.mu.Lock()
+	defer rate.mu.Unlock()
 
 	for key, entry := range rate.tableIPv4 {
-						entry.Lock()
-						if time.Since(entry.lastTime) > garbageCollectTime {
+		entry.mu.Lock()
+		if rate.timeNow().Sub(entry.lastTime) > garbageCollectTime {
 			delete(rate.tableIPv4, key)
 		}
-						entry.Unlock()
+		entry.mu.Unlock()
 	}
 
 	for key, entry := range rate.tableIPv6 {
-						entry.Lock()
-						if time.Since(entry.lastTime) > garbageCollectTime {
+		entry.mu.Lock()
+		if rate.timeNow().Sub(entry.lastTime) > garbageCollectTime {
 			delete(rate.tableIPv6, key)
 		}
-						entry.Unlock()
+		entry.mu.Unlock()
 	}
 
-					if len(rate.tableIPv4) == 0 && len(rate.tableIPv6) == 0 {
-						ticker.Stop()
-					}
-				}()
-			}
-		}
-	}()
+	return len(rate.tableIPv4) == 0 && len(rate.tableIPv6) == 0
 }
 
 func (rate *Ratelimiter) Allow(ip net.IP) bool {
@@ -109,7 +116,7 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 	IPv4 := ip.To4()
 	IPv6 := ip.To16()
 
-	rate.RLock()
+	rate.mu.RLock()
 
 	if IPv4 != nil {
 		copy(keyIPv4[:], IPv4)
@@ -119,15 +126,15 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 		entry = rate.tableIPv6[keyIPv6]
 	}
 
-	rate.RUnlock()
+	rate.mu.RUnlock()
 
 	// make new entry if not found
 
 	if entry == nil {
 		entry = new(RatelimiterEntry)
 		entry.tokens = maxTokens - packetCost
-		entry.lastTime = time.Now()
-		rate.Lock()
+		entry.lastTime = rate.timeNow()
+		rate.mu.Lock()
 		if IPv4 != nil {
 			rate.tableIPv4[keyIPv4] = entry
 			if len(rate.tableIPv4) == 1 && len(rate.tableIPv6) == 0 {
@@ -139,14 +146,14 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 				rate.stopReset <- struct{}{}
 			}
 		}
-		rate.Unlock()
+		rate.mu.Unlock()
 		return true
 	}
 
 	// add tokens to entry
 
-	entry.Lock()
-	now := time.Now()
+	entry.mu.Lock()
+	now := rate.timeNow()
 	entry.tokens += now.Sub(entry.lastTime).Nanoseconds()
 	entry.lastTime = now
 	if entry.tokens > maxTokens {
@@ -157,9 +164,9 @@ func (rate *Ratelimiter) Allow(ip net.IP) bool {
 
 	if entry.tokens > packetCost {
 		entry.tokens -= packetCost
-		entry.Unlock()
+		entry.mu.Unlock()
 		return true
 	}
-	entry.Unlock()
+	entry.mu.Unlock()
 	return false
 }

ratelimiter/ratelimiter_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package ratelimiter
@@ -11,22 +11,21 @@ import (
 	"time"
 )
 
-type RatelimiterResult struct {
+type result struct {
 	allowed bool
 	text    string
 	wait    time.Duration
 }
 
 func TestRatelimiter(t *testing.T) {
+	var rate Ratelimiter
+	var expectedResults []result
 
-	var ratelimiter Ratelimiter
-	var expectedResults []RatelimiterResult
-
-	Nano := func(nano int64) time.Duration {
+	nano := func(nano int64) time.Duration {
 		return time.Nanosecond * time.Duration(nano)
 	}
 
-	Add := func(res RatelimiterResult) {
+	add := func(res result) {
 		expectedResults = append(
 			expectedResults,
 			res,
@@ -34,40 +33,40 @@ func TestRatelimiter(t *testing.T) {
 	}
 
 	for i := 0; i < packetsBurstable; i++ {
-		Add(RatelimiterResult{
+		add(result{
 			allowed: true,
 			text:    "initial burst",
 		})
 	}
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: false,
 		text:    "after burst",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: true,
-		wait:    Nano(time.Second.Nanoseconds() / packetsPerSecond),
+		wait:    nano(time.Second.Nanoseconds() / packetsPerSecond),
 		text:    "filling tokens for single packet",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: false,
 		text:    "not having refilled enough",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: true,
-		wait:    2 * (Nano(time.Second.Nanoseconds() / packetsPerSecond)),
+		wait:    2 * (nano(time.Second.Nanoseconds() / packetsPerSecond)),
 		text:    "filling tokens for two packet burst",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: true,
 		text:    "second packet in 2 packet burst",
 	})
 
-	Add(RatelimiterResult{
+	add(result{
 		allowed: false,
 		text:    "packet following 2 packet burst",
 	})
@@ -89,14 +88,31 @@ func TestRatelimiter(t *testing.T) {
 		net.ParseIP("3f0e:54a2:f5b4:cd19:a21d:58e1:3746:84c4"),
 	}
 
-	ratelimiter.Init()
+	now := time.Now()
+	rate.timeNow = func() time.Time {
+		return now
+	}
+	defer func() {
+		// Lock to avoid data race with cleanup goroutine from Init.
+		rate.mu.Lock()
+		defer rate.mu.Unlock()
+
+		rate.timeNow = time.Now
+	}()
+	timeSleep := func(d time.Duration) {
+		now = now.Add(d + 1)
+		rate.cleanup()
+	}
+
+	rate.Init()
+	defer rate.Close()
 
 	for i, res := range expectedResults {
-		time.Sleep(res.wait)
+		timeSleep(res.wait)
 		for _, ip := range ips {
-			allowed := ratelimiter.Allow(ip)
+			allowed := rate.Allow(ip)
 			if allowed != res.allowed {
-				t.Fatal("Test failed for", ip.String(), ", on:", i, "(", res.text, ")", "expected:", res.allowed, "got:", allowed)
+				t.Fatalf("%d: %s: rate.Allow(%q)=%v, want %v", i, res.text, ip, allowed, res.allowed)
 			}
 		}
 	}

replay/replay.go

@@ -1,83 +1,62 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
+// Package replay implements an efficient anti-replay algorithm as specified in RFC 6479.
 package replay
 
-/* Implementation of RFC6479
- * https://tools.ietf.org/html/rfc6479
- *
- * The implementation is not safe for concurrent use!
- */
+type block uint64
 
 const (
-	// See: https://golang.org/src/math/big/arith.go
-	_Wordm       = ^uintptr(0)
-	_WordLogSize = _Wordm>>8&1 + _Wordm>>16&1 + _Wordm>>32&1
-	_WordSize    = 1 << _WordLogSize
+	blockBitLog = 6                // 1<<6 == 64 bits
+	blockBits   = 1 << blockBitLog // must be power of 2
+	ringBlocks  = 1 << 7           // must be power of 2
+	windowSize  = (ringBlocks - 1) * blockBits
+	blockMask   = ringBlocks - 1
+	bitMask     = blockBits - 1
 )
 
-const (
-	CounterRedundantBitsLog = _WordLogSize + 3
-	CounterRedundantBits    = _WordSize * 8
-	CounterBitsTotal        = 2048
-	CounterWindowSize       = uint64(CounterBitsTotal - CounterRedundantBits)
-)
-
-const (
-	BacktrackWords = CounterBitsTotal / _WordSize
-)
-
-func minUint64(a uint64, b uint64) uint64 {
-	if a > b {
-		return b
-	}
-	return a
+// A Filter rejects replayed messages by checking if message counter value is
+// within a sliding window of previously received messages.
+// The zero value for Filter is an empty filter ready to use.
+// Filters are unsafe for concurrent use.
+type Filter struct {
+	last uint64
+	ring [ringBlocks]block
 }
 
-type ReplayFilter struct {
-	counter   uint64
-	backtrack [BacktrackWords]uintptr
+// Reset resets the filter to empty state.
+func (f *Filter) Reset() {
+	f.last = 0
+	f.ring[0] = 0
 }
 
-func (filter *ReplayFilter) Init() {
-	filter.counter = 0
-	filter.backtrack[0] = 0
-}
-
-func (filter *ReplayFilter) ValidateCounter(counter uint64, limit uint64) bool {
+// ValidateCounter checks if the counter should be accepted.
+// Overlimit counters (>= limit) are always rejected.
+func (f *Filter) ValidateCounter(counter uint64, limit uint64) bool {
 	if counter >= limit {
 		return false
 	}
-
-	indexWord := counter >> CounterRedundantBitsLog
-
-	if counter > filter.counter {
-
-		// move window forward
-
-		current := filter.counter >> CounterRedundantBitsLog
-		diff := minUint64(indexWord-current, BacktrackWords)
-		for i := uint64(1); i <= diff; i++ {
-			filter.backtrack[(current+i)%BacktrackWords] = 0
+	indexBlock := counter >> blockBitLog
+	if counter > f.last { // move window forward
+		current := f.last >> blockBitLog
+		diff := indexBlock - current
+		if diff > ringBlocks {
+			diff = ringBlocks // cap diff to clear the whole ring
 		}
-		filter.counter = counter
-
-	} else if filter.counter-counter > CounterWindowSize {
-
-		// behind current window
-
+		for i := current + 1; i <= current+diff; i++ {
+			f.ring[i&blockMask] = 0
+		}
+		f.last = counter
+	} else if f.last-counter > windowSize { // behind current window
 		return false
 	}
-
-	indexWord %= BacktrackWords
-	indexBit := counter & uint64(CounterRedundantBits-1)
-
 	// check and set bit
-
-	oldValue := filter.backtrack[indexWord]
-	newValue := oldValue | (1 << indexBit)
-	filter.backtrack[indexWord] = newValue
-	return oldValue != newValue
+	indexBlock &= blockMask
+	indexBit := counter & bitMask
+	old := f.ring[indexBlock]
+	new := old | 1<<indexBit
+	f.ring[indexBlock] = new
+	return old != new
 }

replay/replay_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package replay
@@ -14,22 +14,22 @@ import (
  *
  */
 
-const RejectAfterMessages = (1 << 64) - (1 << 4) - 1
+const RejectAfterMessages = 1<<64 - 1<<13 - 1
 
 func TestReplay(t *testing.T) {
-	var filter ReplayFilter
+	var filter Filter
 
-	T_LIM := CounterWindowSize + 1
+	const T_LIM = windowSize + 1
 
 	testNumber := 0
-	T := func(n uint64, v bool) {
+	T := func(n uint64, expected bool) {
 		testNumber++
-		if filter.ValidateCounter(n, RejectAfterMessages) != v {
-			t.Fatal("Test", testNumber, "failed", n, v)
+		if filter.ValidateCounter(n, RejectAfterMessages) != expected {
+			t.Fatal("Test", testNumber, "failed", n, expected)
 		}
 	}
 
-	filter.Init()
+	filter.Reset()
 
 	T(0, true)                      /*  1 */
 	T(1, true)                      /*  2 */
@@ -67,53 +67,53 @@ func TestReplay(t *testing.T) {
 	T(0, false)                     /* 34 */
 
 	t.Log("Bulk test 1")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := uint64(1); i <= CounterWindowSize; i++ {
+	for i := uint64(1); i <= windowSize; i++ {
 		T(i, true)
 	}
 	T(0, true)
 	T(0, false)
 
 	t.Log("Bulk test 2")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := uint64(2); i <= CounterWindowSize+1; i++ {
+	for i := uint64(2); i <= windowSize+1; i++ {
 		T(i, true)
 	}
 	T(1, true)
 	T(0, false)
 
 	t.Log("Bulk test 3")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := CounterWindowSize + 1; i > 0; i-- {
+	for i := uint64(windowSize + 1); i > 0; i-- {
 		T(i, true)
 	}
 
 	t.Log("Bulk test 4")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := CounterWindowSize + 2; i > 1; i-- {
+	for i := uint64(windowSize + 2); i > 1; i-- {
 		T(i, true)
 	}
 	T(0, false)
 
 	t.Log("Bulk test 5")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := CounterWindowSize; i > 0; i-- {
+	for i := uint64(windowSize); i > 0; i-- {
 		T(i, true)
 	}
-	T(CounterWindowSize+1, true)
+	T(windowSize+1, true)
 	T(0, false)
 
 	t.Log("Bulk test 6")
-	filter.Init()
+	filter.Reset()
 	testNumber = 0
-	for i := CounterWindowSize; i > 0; i-- {
+	for i := uint64(windowSize); i > 0; i-- {
 		T(i, true)
 	}
 	T(0, true)
-	T(CounterWindowSize+1, true)
+	T(windowSize+1, true)
 }

rwcancel/fdset.go

@@ -1,6 +1,8 @@
+// +build !windows
+
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package rwcancel

rwcancel/rwcancel.go

@@ -1,8 +1,12 @@
+// +build !windows
+
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
+// Package rwcancel implements cancelable read/write operations on
+// a file descriptor.
 package rwcancel
 
 import (
@@ -42,17 +46,7 @@ func NewRWCancel(fd int) (*RWCancel, error) {
 }
 
 func RetryAfterError(err error) bool {
-	if pe, ok := err.(*os.PathError); ok {
-		err = pe.Err
-	}
-	if errno, ok := err.(syscall.Errno); ok {
-		switch errno {
-		case syscall.EAGAIN, syscall.EINTR:
-			return true
-		}
-
-	}
-	return false
+	return errors.Is(err, syscall.EAGAIN) || errors.Is(err, syscall.EINTR)
 }
 
 func (rw *RWCancel) ReadyRead() bool {
@@ -125,3 +119,8 @@ func (rw *RWCancel) Cancel() (err error) {
 	_, err = rw.closingWriter.Write([]byte{0})
 	return
 }
+
+func (rw *RWCancel) Close() {
+	rw.closingReader.Close()
+	rw.closingWriter.Close()
+}

rwcancel/rwcancel_windows.go

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: MIT
+
+package rwcancel
+
+type RWCancel struct {
+}
+
+func (*RWCancel) Cancel() {}

rwcancel/select_default.go

@@ -1,8 +1,8 @@
-// +build !linux
+// +build !linux,!windows
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package rwcancel
@@ -10,5 +10,6 @@ package rwcancel
 import "golang.org/x/sys/unix"
 
 func unixSelect(nfd int, r *unix.FdSet, w *unix.FdSet, e *unix.FdSet, timeout *unix.Timeval) error {
-	return unix.Select(nfd, r, w, e, timeout)
+	_, err := unix.Select(nfd, r, w, e, timeout)
+	return err
 }

rwcancel/select_linux.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package rwcancel

tai64n/tai64n.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tai64n
@@ -17,16 +17,23 @@ const whitenerMask = uint32(0x1000000 - 1)
 
 type Timestamp [TimestampSize]byte
 
-func Now() Timestamp {
+func stamp(t time.Time) Timestamp {
 	var tai64n Timestamp
-	now := time.Now()
-	secs := base + uint64(now.Unix())
-	nano := uint32(now.Nanosecond()) &^ whitenerMask
+	secs := base + uint64(t.Unix())
+	nano := uint32(t.Nanosecond()) &^ whitenerMask
 	binary.BigEndian.PutUint64(tai64n[:], secs)
 	binary.BigEndian.PutUint32(tai64n[8:], nano)
 	return tai64n
 }
 
+func Now() Timestamp {
+	return stamp(time.Now())
+}
+
 func (t1 Timestamp) After(t2 Timestamp) bool {
 	return bytes.Compare(t1[:], t2[:]) > 0
 }
+
+func (t Timestamp) String() string {
+	return time.Unix(int64(binary.BigEndian.Uint64(t[:8])-base), int64(binary.BigEndian.Uint32(t[8:12]))).String()
+}

tai64n/tai64n_test.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tai64n
@@ -10,21 +10,31 @@ import (
 	"time"
 )
 
-/* Testing the essential property of the timestamp
- * as used by WireGuard.
- */
+// Test that timestamps are monotonic as required by Wireguard and that
+// nanosecond-level information is whitened to prevent side channel attacks.
 func TestMonotonic(t *testing.T) {
-	old := Now()
-	for i := 0; i < 50; i++ {
-		next := Now()
-		if next.After(old) {
-			t.Error("Whitening insufficient")
+	startTime := time.Unix(0, 123456789) // a nontrivial bit pattern
+	// Whitening should reduce timestamp granularity
+	// to more than 10 but fewer than 20 milliseconds.
+	tests := []struct {
+		name      string
+		t1, t2    time.Time
+		wantAfter bool
+	}{
+		{"after_10_ns", startTime, startTime.Add(10 * time.Nanosecond), false},
+		{"after_10_us", startTime, startTime.Add(10 * time.Microsecond), false},
+		{"after_1_ms", startTime, startTime.Add(time.Millisecond), false},
+		{"after_10_ms", startTime, startTime.Add(10 * time.Millisecond), false},
+		{"after_20_ms", startTime, startTime.Add(20 * time.Millisecond), true},
 	}
-		time.Sleep(time.Duration(whitenerMask)/time.Nanosecond + 1)
-		next = Now()
-		if !next.After(old) {
-			t.Error("Not monotonically increasing on whitened nano-second scale")
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ts1, ts2 := stamp(tt.t1), stamp(tt.t2)
+			got := ts2.After(ts1)
+			if got != tt.wantAfter {
+				t.Errorf("after = %v; want %v", got, tt.wantAfter)
 			}
-		old = next
+		})
 	}
 }

tests/netns.sh

@@ -36,7 +36,7 @@ netns0="wg-test-$$-0"
 netns1="wg-test-$$-1"
 netns2="wg-test-$$-2"
 program=$1
-export LOG_LEVEL="info"
+export LOG_LEVEL="verbose"
 
 pretty() { echo -e "\x1b[32m\x1b[1m[+] ${1:+NS$1: }${2}\x1b[0m" >&3; }
 pp() { pretty "" "$*"; "$@"; }

tun/netstack/examples/http_client.go

@@ -0,0 +1,53 @@
+// +build ignore
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package main
+
+import (
+	"io"
+	"log"
+	"net"
+	"net/http"
+
+	"golang.zx2c4.com/wireguard/device"
+	"golang.zx2c4.com/wireguard/tun/netstack"
+)
+
+func main() {
+	tun, tnet, err := netstack.CreateNetTUN(
+		[]net.IP{net.ParseIP("192.168.4.29")},
+		[]net.IP{net.ParseIP("8.8.8.8")},
+		1420)
+	if err != nil {
+		log.Panic(err)
+	}
+	dev := device.NewDevice(tun, &device.Logger{log.Default(), log.Default(), log.Default()})
+	dev.IpcSet(`private_key=a8dac1d8a70a751f0f699fb14ba1cff7b79cf4fbd8f09f44c6e6a90d0369604f
+public_key=25123c5dcd3328ff645e4f2a3fce0d754400d3887a0cb7c56f0267e20fbf3c5b
+endpoint=163.172.161.0:12912
+allowed_ip=0.0.0.0/0
+`)
+	err = dev.Up()
+	if err != nil {
+		log.Panic(err)
+	}
+
+	client := http.Client{
+		Transport: &http.Transport{
+			DialContext: tnet.DialContext,
+		},
+	}
+	resp, err := client.Get("https://www.zx2c4.com/ip")
+	if err != nil {
+		log.Panic(err)
+	}
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		log.Panic(err)
+	}
+	log.Println(string(body))
+}

tun/netstack/examples/http_server.go

@@ -0,0 +1,48 @@
+// +build ignore
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package main
+
+import (
+	"golang.zx2c4.com/wireguard/device"
+	"golang.zx2c4.com/wireguard/tun/netstack"
+	"io"
+	"log"
+	"net"
+	"net/http"
+)
+
+func main() {
+	tun, tnet, err := netstack.CreateNetTUN(
+		[]net.IP{net.ParseIP("192.168.4.29")},
+		[]net.IP{net.ParseIP("8.8.8.8"), net.ParseIP("8.8.4.4")},
+		1420,
+	)
+	if err != nil {
+		log.Panic(err)
+	}
+	dev := device.NewDevice(tun, &device.Logger{log.Default(), log.Default(), log.Default()})
+	dev.IpcSet(`private_key=a8dac1d8a70a751f0f699fb14ba1cff7b79cf4fbd8f09f44c6e6a90d0369604f
+public_key=25123c5dcd3328ff645e4f2a3fce0d754400d3887a0cb7c56f0267e20fbf3c5b
+endpoint=163.172.161.0:12912
+allowed_ip=0.0.0.0/0
+persistent_keepalive_interval=25
+    `)
+	dev.Up()
+	listener, err := tnet.ListenTCP(&net.TCPAddr{Port: 80})
+	if err != nil {
+		log.Panicln(err)
+	}
+	http.HandleFunc("/", func(writer http.ResponseWriter, request *http.Request) {
+		log.Printf("> %s - %s - %s", request.RemoteAddr, request.URL.String(), request.UserAgent())
+		io.WriteString(writer, "Hello from userspace TCP!")
+	})
+	err = http.Serve(listener, nil)
+	if err != nil {
+		log.Panicln(err)
+	}
+}

tun/netstack/go.mod

@@ -0,0 +1,9 @@
+module golang.zx2c4.com/wireguard/tun/netstack
+
+go 1.15
+
+require (
+	golang.org/x/net v0.0.0-20201110031124-69a78807bb2b
+	golang.zx2c4.com/wireguard v0.0.20201118
+	gvisor.dev/gvisor v0.0.0-20210109011639-2fb7a49fea98
+)

tun/netstack/go.sum

@@ -0,0 +1,391 @@
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+cloud.google.com/go v0.44.2/go.mod h1:60680Gw3Yr4ikxnPRS/oxxkBccT6SA1yMk63TGekxKY=
+cloud.google.com/go v0.45.1/go.mod h1:RpBamKRgapWJb87xiFSdk4g1CME7QZg3uwTez+TSTjc=
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tun/netstack/tun.go

@@ -0,0 +1,818 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package netstack
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"golang.zx2c4.com/wireguard/tun"
+
+	"golang.org/x/net/dns/dnsmessage"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
+	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
+)
+
+type netTun struct {
+	stack          *stack.Stack
+	dispatcher     stack.NetworkDispatcher
+	events         chan tun.Event
+	incomingPacket chan buffer.VectorisedView
+	mtu            int
+	dnsServers     []net.IP
+	hasV4, hasV6   bool
+}
+type endpoint netTun
+type Net netTun
+
+func (e *endpoint) Attach(dispatcher stack.NetworkDispatcher) {
+	e.dispatcher = dispatcher
+}
+
+func (e *endpoint) IsAttached() bool {
+	return e.dispatcher != nil
+}
+
+func (e *endpoint) MTU() uint32 {
+	mtu, err := (*netTun)(e).MTU()
+	if err != nil {
+		panic(err)
+	}
+	return uint32(mtu)
+}
+
+func (*endpoint) Capabilities() stack.LinkEndpointCapabilities {
+	return stack.CapabilityNone
+}
+
+func (*endpoint) MaxHeaderLength() uint16 {
+	return 0
+}
+
+func (*endpoint) LinkAddress() tcpip.LinkAddress {
+	return ""
+}
+
+func (*endpoint) Wait() {}
+
+func (e *endpoint) WritePacket(_ *stack.Route, _ *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error {
+	e.incomingPacket <- buffer.NewVectorisedView(pkt.Size(), pkt.Views())
+	return nil
+}
+
+func (e *endpoint) WritePackets(*stack.Route, *stack.GSO, stack.PacketBufferList, tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
+	panic("not implemented")
+}
+
+func (*endpoint) ARPHardwareType() header.ARPHardwareType {
+	return header.ARPHardwareNone
+}
+
+func (e *endpoint) AddHeader(local, remote tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
+}
+
+func CreateNetTUN(localAddresses []net.IP, dnsServers []net.IP, mtu int) (tun.Device, *Net, error) {
+	opts := stack.Options{
+		NetworkProtocols:   []stack.NetworkProtocolFactory{ipv4.NewProtocol, ipv6.NewProtocol},
+		TransportProtocols: []stack.TransportProtocolFactory{tcp.NewProtocol, udp.NewProtocol},
+		HandleLocal:        true,
+	}
+	dev := &netTun{
+		stack:          stack.New(opts),
+		events:         make(chan tun.Event, 10),
+		incomingPacket: make(chan buffer.VectorisedView),
+		dnsServers:     dnsServers,
+		mtu:            mtu,
+	}
+	tcpipErr := dev.stack.CreateNIC(1, (*endpoint)(dev))
+	if tcpipErr != nil {
+		return nil, nil, fmt.Errorf("CreateNIC: %v", tcpipErr)
+	}
+	for _, ip := range localAddresses {
+		if ip4 := ip.To4(); ip4 != nil {
+			tcpipErr = dev.stack.AddAddress(1, ipv4.ProtocolNumber, tcpip.Address(ip4))
+			if tcpipErr != nil {
+				return nil, nil, fmt.Errorf("AddAddress(%v): %v", ip4, tcpipErr)
+			}
+			dev.hasV4 = true
+		} else {
+			tcpipErr = dev.stack.AddAddress(1, ipv6.ProtocolNumber, tcpip.Address(ip))
+			if tcpipErr != nil {
+				return nil, nil, fmt.Errorf("AddAddress(%v): %v", ip4, tcpipErr)
+			}
+			dev.hasV6 = true
+		}
+	}
+	if dev.hasV4 {
+		dev.stack.AddRoute(tcpip.Route{Destination: header.IPv4EmptySubnet, NIC: 1})
+	}
+	if dev.hasV6 {
+		dev.stack.AddRoute(tcpip.Route{Destination: header.IPv6EmptySubnet, NIC: 1})
+	}
+
+	dev.events <- tun.EventUp
+	return dev, (*Net)(dev), nil
+}
+
+func (tun *netTun) Name() (string, error) {
+	return "go", nil
+}
+
+func (tun *netTun) File() *os.File {
+	return nil
+}
+
+func (tun *netTun) Events() chan tun.Event {
+	return tun.events
+}
+
+func (tun *netTun) Read(buf []byte, offset int) (int, error) {
+	view, ok := <-tun.incomingPacket
+	if !ok {
+		return 0, os.ErrClosed
+	}
+	return view.Read(buf[offset:])
+}
+
+func (tun *netTun) Write(buf []byte, offset int) (int, error) {
+	packet := buf[offset:]
+	if len(packet) == 0 {
+		return 0, nil
+	}
+
+	pkb := stack.NewPacketBuffer(stack.PacketBufferOptions{Data: buffer.NewVectorisedView(len(packet), []buffer.View{buffer.NewViewFromBytes(packet)})})
+	switch packet[0] >> 4 {
+	case 4:
+		tun.dispatcher.DeliverNetworkPacket("", "", ipv4.ProtocolNumber, pkb)
+	case 6:
+		tun.dispatcher.DeliverNetworkPacket("", "", ipv6.ProtocolNumber, pkb)
+	}
+
+	return len(buf), nil
+}
+
+func (tun *netTun) Flush() error {
+	return nil
+}
+
+func (tun *netTun) Close() error {
+	tun.stack.RemoveNIC(1)
+
+	if tun.events != nil {
+		close(tun.events)
+	}
+	if tun.incomingPacket != nil {
+		close(tun.incomingPacket)
+	}
+	return nil
+}
+
+func (tun *netTun) MTU() (int, error) {
+	return tun.mtu, nil
+}
+
+func convertToFullAddr(ip net.IP, port int) (tcpip.FullAddress, tcpip.NetworkProtocolNumber) {
+	if ip4 := ip.To4(); ip4 != nil {
+		return tcpip.FullAddress{
+			NIC:  1,
+			Addr: tcpip.Address(ip4),
+			Port: uint16(port),
+		}, ipv4.ProtocolNumber
+	} else {
+		return tcpip.FullAddress{
+			NIC:  1,
+			Addr: tcpip.Address(ip),
+			Port: uint16(port),
+		}, ipv6.ProtocolNumber
+	}
+}
+
+func (net *Net) DialContextTCP(ctx context.Context, addr *net.TCPAddr) (*gonet.TCPConn, error) {
+	if addr == nil {
+		panic("todo: deal with auto addr semantics for nil addr")
+	}
+	fa, pn := convertToFullAddr(addr.IP, addr.Port)
+	return gonet.DialContextTCP(ctx, net.stack, fa, pn)
+}
+
+func (net *Net) DialTCP(addr *net.TCPAddr) (*gonet.TCPConn, error) {
+	if addr == nil {
+		panic("todo: deal with auto addr semantics for nil addr")
+	}
+	fa, pn := convertToFullAddr(addr.IP, addr.Port)
+	return gonet.DialTCP(net.stack, fa, pn)
+}
+
+func (net *Net) ListenTCP(addr *net.TCPAddr) (*gonet.TCPListener, error) {
+	if addr == nil {
+		panic("todo: deal with auto addr semantics for nil addr")
+	}
+	fa, pn := convertToFullAddr(addr.IP, addr.Port)
+	return gonet.ListenTCP(net.stack, fa, pn)
+}
+
+func (net *Net) DialUDP(laddr, raddr *net.UDPAddr) (*gonet.UDPConn, error) {
+	var lfa, rfa *tcpip.FullAddress
+	var pn tcpip.NetworkProtocolNumber
+	if laddr != nil {
+		var addr tcpip.FullAddress
+		addr, pn = convertToFullAddr(laddr.IP, laddr.Port)
+		lfa = &addr
+	}
+	if raddr != nil {
+		var addr tcpip.FullAddress
+		addr, pn = convertToFullAddr(raddr.IP, raddr.Port)
+		rfa = &addr
+	}
+	return gonet.DialUDP(net.stack, lfa, rfa, pn)
+}
+
+var (
+	errNoSuchHost                   = errors.New("no such host")
+	errLameReferral                 = errors.New("lame referral")
+	errCannotUnmarshalDNSMessage    = errors.New("cannot unmarshal DNS message")
+	errCannotMarshalDNSMessage      = errors.New("cannot marshal DNS message")
+	errServerMisbehaving            = errors.New("server misbehaving")
+	errInvalidDNSResponse           = errors.New("invalid DNS response")
+	errNoAnswerFromDNSServer        = errors.New("no answer from DNS server")
+	errServerTemporarilyMisbehaving = errors.New("server misbehaving")
+	errCanceled                     = errors.New("operation was canceled")
+	errTimeout                      = errors.New("i/o timeout")
+	errNumericPort                  = errors.New("port must be numeric")
+	errNoSuitableAddress            = errors.New("no suitable address found")
+	errMissingAddress               = errors.New("missing address")
+)
+
+func (net *Net) LookupHost(host string) (addrs []string, err error) {
+	return net.LookupContextHost(context.Background(), host)
+}
+
+func isDomainName(s string) bool {
+	l := len(s)
+	if l == 0 || l > 254 || l == 254 && s[l-1] != '.' {
+		return false
+	}
+	last := byte('.')
+	nonNumeric := false
+	partlen := 0
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		switch {
+		default:
+			return false
+		case 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || c == '_':
+			nonNumeric = true
+			partlen++
+		case '0' <= c && c <= '9':
+			partlen++
+		case c == '-':
+			if last == '.' {
+				return false
+			}
+			partlen++
+			nonNumeric = true
+		case c == '.':
+			if last == '.' || last == '-' {
+				return false
+			}
+			if partlen > 63 || partlen == 0 {
+				return false
+			}
+			partlen = 0
+		}
+		last = c
+	}
+	if last == '-' || partlen > 63 {
+		return false
+	}
+	return nonNumeric
+}
+
+func randU16() uint16 {
+	var b [2]byte
+	_, err := rand.Read(b[:])
+	if err != nil {
+		panic(err)
+	}
+	return binary.LittleEndian.Uint16(b[:])
+}
+
+func newRequest(q dnsmessage.Question) (id uint16, udpReq, tcpReq []byte, err error) {
+	id = randU16()
+	b := dnsmessage.NewBuilder(make([]byte, 2, 514), dnsmessage.Header{ID: id, RecursionDesired: true})
+	b.EnableCompression()
+	if err := b.StartQuestions(); err != nil {
+		return 0, nil, nil, err
+	}
+	if err := b.Question(q); err != nil {
+		return 0, nil, nil, err
+	}
+	tcpReq, err = b.Finish()
+	udpReq = tcpReq[2:]
+	l := len(tcpReq) - 2
+	tcpReq[0] = byte(l >> 8)
+	tcpReq[1] = byte(l)
+	return id, udpReq, tcpReq, err
+}
+
+func equalASCIIName(x, y dnsmessage.Name) bool {
+	if x.Length != y.Length {
+		return false
+	}
+	for i := 0; i < int(x.Length); i++ {
+		a := x.Data[i]
+		b := y.Data[i]
+		if 'A' <= a && a <= 'Z' {
+			a += 0x20
+		}
+		if 'A' <= b && b <= 'Z' {
+			b += 0x20
+		}
+		if a != b {
+			return false
+		}
+	}
+	return true
+}
+
+func checkResponse(reqID uint16, reqQues dnsmessage.Question, respHdr dnsmessage.Header, respQues dnsmessage.Question) bool {
+	if !respHdr.Response {
+		return false
+	}
+	if reqID != respHdr.ID {
+		return false
+	}
+	if reqQues.Type != respQues.Type || reqQues.Class != respQues.Class || !equalASCIIName(reqQues.Name, respQues.Name) {
+		return false
+	}
+	return true
+}
+
+func dnsPacketRoundTrip(c net.Conn, id uint16, query dnsmessage.Question, b []byte) (dnsmessage.Parser, dnsmessage.Header, error) {
+	if _, err := c.Write(b); err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, err
+	}
+	b = make([]byte, 512)
+	for {
+		n, err := c.Read(b)
+		if err != nil {
+			return dnsmessage.Parser{}, dnsmessage.Header{}, err
+		}
+		var p dnsmessage.Parser
+		h, err := p.Start(b[:n])
+		if err != nil {
+			continue
+		}
+		q, err := p.Question()
+		if err != nil || !checkResponse(id, query, h, q) {
+			continue
+		}
+		return p, h, nil
+	}
+}
+
+func dnsStreamRoundTrip(c net.Conn, id uint16, query dnsmessage.Question, b []byte) (dnsmessage.Parser, dnsmessage.Header, error) {
+	if _, err := c.Write(b); err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, err
+	}
+	b = make([]byte, 1280)
+	if _, err := io.ReadFull(c, b[:2]); err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, err
+	}
+	l := int(b[0])<<8 | int(b[1])
+	if l > len(b) {
+		b = make([]byte, l)
+	}
+	n, err := io.ReadFull(c, b[:l])
+	if err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, err
+	}
+	var p dnsmessage.Parser
+	h, err := p.Start(b[:n])
+	if err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotUnmarshalDNSMessage
+	}
+	q, err := p.Question()
+	if err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotUnmarshalDNSMessage
+	}
+	if !checkResponse(id, query, h, q) {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errInvalidDNSResponse
+	}
+	return p, h, nil
+}
+
+func (tnet *Net) exchange(ctx context.Context, server net.IP, q dnsmessage.Question, timeout time.Duration) (dnsmessage.Parser, dnsmessage.Header, error) {
+	q.Class = dnsmessage.ClassINET
+	id, udpReq, tcpReq, err := newRequest(q)
+	if err != nil {
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotMarshalDNSMessage
+	}
+
+	for _, useUDP := range []bool{true, false} {
+		ctx, cancel := context.WithDeadline(ctx, time.Now().Add(timeout))
+		defer cancel()
+
+		var c net.Conn
+		var err error
+		if useUDP {
+			c, err = tnet.DialUDP(nil, &net.UDPAddr{IP: server, Port: 53})
+		} else {
+			c, err = tnet.DialContextTCP(ctx, &net.TCPAddr{IP: server, Port: 53})
+		}
+
+		if err != nil {
+			return dnsmessage.Parser{}, dnsmessage.Header{}, err
+		}
+		if d, ok := ctx.Deadline(); ok && !d.IsZero() {
+			c.SetDeadline(d)
+		}
+		var p dnsmessage.Parser
+		var h dnsmessage.Header
+		if useUDP {
+			p, h, err = dnsPacketRoundTrip(c, id, q, udpReq)
+		} else {
+			p, h, err = dnsStreamRoundTrip(c, id, q, tcpReq)
+		}
+		c.Close()
+		if err != nil {
+			if err == context.Canceled {
+				err = errCanceled
+			} else if err == context.DeadlineExceeded {
+				err = errTimeout
+			}
+			return dnsmessage.Parser{}, dnsmessage.Header{}, err
+		}
+		if err := p.SkipQuestion(); err != dnsmessage.ErrSectionDone {
+			return dnsmessage.Parser{}, dnsmessage.Header{}, errInvalidDNSResponse
+		}
+		if h.Truncated {
+			continue
+		}
+		return p, h, nil
+	}
+	return dnsmessage.Parser{}, dnsmessage.Header{}, errNoAnswerFromDNSServer
+}
+
+func checkHeader(p *dnsmessage.Parser, h dnsmessage.Header) error {
+	if h.RCode == dnsmessage.RCodeNameError {
+		return errNoSuchHost
+	}
+	_, err := p.AnswerHeader()
+	if err != nil && err != dnsmessage.ErrSectionDone {
+		return errCannotUnmarshalDNSMessage
+	}
+	if h.RCode == dnsmessage.RCodeSuccess && !h.Authoritative && !h.RecursionAvailable && err == dnsmessage.ErrSectionDone {
+		return errLameReferral
+	}
+	if h.RCode != dnsmessage.RCodeSuccess && h.RCode != dnsmessage.RCodeNameError {
+		if h.RCode == dnsmessage.RCodeServerFailure {
+			return errServerTemporarilyMisbehaving
+		}
+		return errServerMisbehaving
+	}
+	return nil
+}
+
+func skipToAnswer(p *dnsmessage.Parser, qtype dnsmessage.Type) error {
+	for {
+		h, err := p.AnswerHeader()
+		if err == dnsmessage.ErrSectionDone {
+			return errNoSuchHost
+		}
+		if err != nil {
+			return errCannotUnmarshalDNSMessage
+		}
+		if h.Type == qtype {
+			return nil
+		}
+		if err := p.SkipAnswer(); err != nil {
+			return errCannotUnmarshalDNSMessage
+		}
+	}
+}
+
+func (tnet *Net) tryOneName(ctx context.Context, name string, qtype dnsmessage.Type) (dnsmessage.Parser, string, error) {
+	var lastErr error
+
+	n, err := dnsmessage.NewName(name)
+	if err != nil {
+		return dnsmessage.Parser{}, "", errCannotMarshalDNSMessage
+	}
+	q := dnsmessage.Question{
+		Name:  n,
+		Type:  qtype,
+		Class: dnsmessage.ClassINET,
+	}
+
+	for i := 0; i < 2; i++ {
+		for _, server := range tnet.dnsServers {
+			p, h, err := tnet.exchange(ctx, server, q, time.Second*5)
+			if err != nil {
+				dnsErr := &net.DNSError{
+					Err:    err.Error(),
+					Name:   name,
+					Server: server.String(),
+				}
+				if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
+					dnsErr.IsTimeout = true
+				}
+				if _, ok := err.(*net.OpError); ok {
+					dnsErr.IsTemporary = true
+				}
+				lastErr = dnsErr
+				continue
+			}
+
+			if err := checkHeader(&p, h); err != nil {
+				dnsErr := &net.DNSError{
+					Err:    err.Error(),
+					Name:   name,
+					Server: server.String(),
+				}
+				if err == errServerTemporarilyMisbehaving {
+					dnsErr.IsTemporary = true
+				}
+				if err == errNoSuchHost {
+					dnsErr.IsNotFound = true
+					return p, server.String(), dnsErr
+				}
+				lastErr = dnsErr
+				continue
+			}
+
+			err = skipToAnswer(&p, qtype)
+			if err == nil {
+				return p, server.String(), nil
+			}
+			lastErr = &net.DNSError{
+				Err:    err.Error(),
+				Name:   name,
+				Server: server.String(),
+			}
+			if err == errNoSuchHost {
+				lastErr.(*net.DNSError).IsNotFound = true
+				return p, server.String(), lastErr
+			}
+		}
+	}
+	return dnsmessage.Parser{}, "", lastErr
+}
+
+func (tnet *Net) LookupContextHost(ctx context.Context, host string) ([]string, error) {
+	if host == "" || (!tnet.hasV6 && !tnet.hasV4) {
+		return nil, &net.DNSError{Err: errNoSuchHost.Error(), Name: host, IsNotFound: true}
+	}
+	zlen := len(host)
+	if strings.IndexByte(host, ':') != -1 {
+		if zidx := strings.LastIndexByte(host, '%'); zidx != -1 {
+			zlen = zidx
+		}
+	}
+	if ip := net.ParseIP(host[:zlen]); ip != nil {
+		return []string{host[:zlen]}, nil
+	}
+
+	if !isDomainName(host) {
+		return nil, &net.DNSError{Err: errNoSuchHost.Error(), Name: host, IsNotFound: true}
+	}
+	type result struct {
+		p      dnsmessage.Parser
+		server string
+		error
+	}
+	var addrsV4, addrsV6 []net.IP
+	lanes := 0
+	if tnet.hasV4 {
+		lanes++
+	}
+	if tnet.hasV6 {
+		lanes++
+	}
+	lane := make(chan result, lanes)
+	var lastErr error
+	if tnet.hasV4 {
+		go func() {
+			p, server, err := tnet.tryOneName(ctx, host+".", dnsmessage.TypeA)
+			lane <- result{p, server, err}
+		}()
+	}
+	if tnet.hasV6 {
+		go func() {
+			p, server, err := tnet.tryOneName(ctx, host+".", dnsmessage.TypeAAAA)
+			lane <- result{p, server, err}
+		}()
+	}
+	for l := 0; l < lanes; l++ {
+		result := <-lane
+		if result.error != nil {
+			if lastErr == nil {
+				lastErr = result.error
+			}
+			continue
+		}
+
+	loop:
+		for {
+			h, err := result.p.AnswerHeader()
+			if err != nil && err != dnsmessage.ErrSectionDone {
+				lastErr = &net.DNSError{
+					Err:    errCannotMarshalDNSMessage.Error(),
+					Name:   host,
+					Server: result.server,
+				}
+			}
+			if err != nil {
+				break
+			}
+			switch h.Type {
+			case dnsmessage.TypeA:
+				a, err := result.p.AResource()
+				if err != nil {
+					lastErr = &net.DNSError{
+						Err:    errCannotMarshalDNSMessage.Error(),
+						Name:   host,
+						Server: result.server,
+					}
+					break loop
+				}
+				addrsV4 = append(addrsV4, net.IP(a.A[:]))
+
+			case dnsmessage.TypeAAAA:
+				aaaa, err := result.p.AAAAResource()
+				if err != nil {
+					lastErr = &net.DNSError{
+						Err:    errCannotMarshalDNSMessage.Error(),
+						Name:   host,
+						Server: result.server,
+					}
+					break loop
+				}
+				addrsV6 = append(addrsV6, net.IP(aaaa.AAAA[:]))
+
+			default:
+				if err := result.p.SkipAnswer(); err != nil {
+					lastErr = &net.DNSError{
+						Err:    errCannotMarshalDNSMessage.Error(),
+						Name:   host,
+						Server: result.server,
+					}
+					break loop
+				}
+				continue
+			}
+		}
+	}
+	// We don't do RFC6724. Instead just put V6 addresess first if an IPv6 address is enabled
+	var addrs []net.IP
+	if tnet.hasV6 {
+		addrs = append(addrsV6, addrsV4...)
+	} else {
+		addrs = append(addrsV4, addrsV6...)
+	}
+
+	if len(addrs) == 0 && lastErr != nil {
+		return nil, lastErr
+	}
+	saddrs := make([]string, 0, len(addrs))
+	for _, ip := range addrs {
+		saddrs = append(saddrs, ip.String())
+	}
+	return saddrs, nil
+}
+
+func partialDeadline(now, deadline time.Time, addrsRemaining int) (time.Time, error) {
+	if deadline.IsZero() {
+		return deadline, nil
+	}
+	timeRemaining := deadline.Sub(now)
+	if timeRemaining <= 0 {
+		return time.Time{}, errTimeout
+	}
+	timeout := timeRemaining / time.Duration(addrsRemaining)
+	const saneMinimum = 2 * time.Second
+	if timeout < saneMinimum {
+		if timeRemaining < saneMinimum {
+			timeout = timeRemaining
+		} else {
+			timeout = saneMinimum
+		}
+	}
+	return now.Add(timeout), nil
+}
+
+func (tnet *Net) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	if ctx == nil {
+		panic("nil context")
+	}
+	var acceptV4, acceptV6, useUDP bool
+	if len(network) == 3 {
+		acceptV4 = true
+		acceptV6 = true
+	} else if len(network) == 4 {
+		acceptV4 = network[3] == '4'
+		acceptV6 = network[3] == '6'
+	}
+	if !acceptV4 && !acceptV6 {
+		return nil, &net.OpError{Op: "dial", Err: net.UnknownNetworkError(network)}
+	}
+	if network[:3] == "udp" {
+		useUDP = true
+	} else if network[:3] != "tcp" {
+		return nil, &net.OpError{Op: "dial", Err: net.UnknownNetworkError(network)}
+	}
+	host, sport, err := net.SplitHostPort(address)
+	if err != nil {
+		return nil, &net.OpError{Op: "dial", Err: err}
+	}
+	port, err := strconv.Atoi(sport)
+	if err != nil || port < 0 || port > 65535 {
+		return nil, &net.OpError{Op: "dial", Err: errNumericPort}
+	}
+	allAddr, err := tnet.LookupContextHost(ctx, host)
+	if err != nil {
+		return nil, &net.OpError{Op: "dial", Err: err}
+	}
+	var addrs []net.IP
+	for _, addr := range allAddr {
+		if strings.IndexByte(addr, ':') != -1 && acceptV6 {
+			addrs = append(addrs, net.ParseIP(addr))
+		} else if strings.IndexByte(addr, '.') != -1 && acceptV4 {
+			addrs = append(addrs, net.ParseIP(addr))
+		}
+	}
+	if len(addrs) == 0 && len(allAddr) != 0 {
+		return nil, &net.OpError{Op: "dial", Err: errNoSuitableAddress}
+	}
+
+	var firstErr error
+	for i, addr := range addrs {
+		select {
+		case <-ctx.Done():
+			err := ctx.Err()
+			if err == context.Canceled {
+				err = errCanceled
+			} else if err == context.DeadlineExceeded {
+				err = errTimeout
+			}
+			return nil, &net.OpError{Op: "dial", Err: err}
+		default:
+		}
+
+		dialCtx := ctx
+		if deadline, hasDeadline := ctx.Deadline(); hasDeadline {
+			partialDeadline, err := partialDeadline(time.Now(), deadline, len(addrs)-i)
+			if err != nil {
+				if firstErr == nil {
+					firstErr = &net.OpError{Op: "dial", Err: err}
+				}
+				break
+			}
+			if partialDeadline.Before(deadline) {
+				var cancel context.CancelFunc
+				dialCtx, cancel = context.WithDeadline(ctx, partialDeadline)
+				defer cancel()
+			}
+		}
+
+		var c net.Conn
+		if useUDP {
+			c, err = tnet.DialUDP(nil, &net.UDPAddr{IP: addr, Port: port})
+		} else {
+			c, err = tnet.DialContextTCP(dialCtx, &net.TCPAddr{IP: addr, Port: port})
+		}
+		if err == nil {
+			return c, nil
+		}
+		if firstErr == nil {
+			firstErr = err
+		}
+	}
+	if firstErr == nil {
+		firstErr = &net.OpError{Op: "dial", Err: errMissingAddress}
+	}
+	return nil, firstErr
+}
+
+func (tnet *Net) Dial(network, address string) (net.Conn, error) {
+	return tnet.DialContext(context.Background(), network, address)
+}

tun/operateonfd.go

@@ -2,7 +2,7 @@
 
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun

tun/tun.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun

tun/tun_darwin.go

@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -20,19 +21,6 @@ import (
 
 const utunControlName = "com.apple.net.utun_control"
 
-// _CTLIOCGINFO value derived from /usr/include/sys/{kern_control,ioccom}.h
-const _CTLIOCGINFO = (0x40000000 | 0x80000000) | ((100 & 0x1fff) << 16) | uint32(byte('N'))<<8 | 3
-
-// sockaddr_ctl specifeid in /usr/include/sys/kern_control.h
-type sockaddrCtl struct {
-	scLen      uint8
-	scFamily   uint8
-	ssSysaddr  uint16
-	scID       uint32
-	scUnit     uint32
-	scReserved [5]uint32
-}
-
 type NativeTun struct {
 	name        string
 	tunFile     *os.File
@@ -41,19 +29,13 @@ type NativeTun struct {
 	routeSocket int
 }
 
-var sockaddrCtlSize uintptr = 32
-
 func retryInterfaceByIndex(index int) (iface *net.Interface, err error) {
 	for i := 0; i < 20; i++ {
 		iface, err = net.InterfaceByIndex(index)
-		if err != nil {
-			if opErr, ok := err.(*net.OpError); ok {
-				if syscallErr, ok := opErr.Err.(*os.SyscallError); ok && syscallErr.Err == syscall.ENOMEM {
+		if err != nil && errors.Is(err, syscall.ENOMEM) {
 			time.Sleep(time.Duration(i) * time.Second / 3)
 			continue
 		}
-			}
-		}
 		return iface, err
 	}
 	return nil, err
@@ -130,43 +112,21 @@ func CreateTUN(name string, mtu int) (Device, error) {
 		return nil, err
 	}
 
-	var ctlInfo = &struct {
-		ctlID   uint32
-		ctlName [96]byte
-	}{}
-
-	copy(ctlInfo.ctlName[:], []byte(utunControlName))
-
-	_, _, errno := unix.Syscall(
-		unix.SYS_IOCTL,
-		uintptr(fd),
-		uintptr(_CTLIOCGINFO),
-		uintptr(unsafe.Pointer(ctlInfo)),
-	)
-
-	if errno != 0 {
-		return nil, fmt.Errorf("_CTLIOCGINFO: %v", errno)
+	ctlInfo := &unix.CtlInfo{}
+	copy(ctlInfo.Name[:], []byte(utunControlName))
+	err = unix.IoctlCtlInfo(fd, ctlInfo)
+	if err != nil {
+		return nil, fmt.Errorf("IoctlGetCtlInfo: %w", err)
 	}
 
-	sc := sockaddrCtl{
-		scLen:     uint8(sockaddrCtlSize),
-		scFamily:  unix.AF_SYSTEM,
-		ssSysaddr: 2,
-		scID:      ctlInfo.ctlID,
-		scUnit:    uint32(ifIndex) + 1,
+	sc := &unix.SockaddrCtl{
+		ID:   ctlInfo.Id,
+		Unit: uint32(ifIndex) + 1,
 	}
 
-	scPointer := unsafe.Pointer(&sc)
-
-	_, _, errno = unix.RawSyscall(
-		unix.SYS_CONNECT,
-		uintptr(fd),
-		uintptr(scPointer),
-		uintptr(sockaddrCtlSize),
-	)
-
-	if errno != 0 {
-		return nil, fmt.Errorf("SYS_CONNECT: %v", errno)
+	err = unix.Connect(fd, sc)
+	if err != nil {
+		return nil, err
 	}
 
 	err = syscall.SetNonblock(fd, true)
@@ -230,27 +190,19 @@ func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
 }
 
 func (tun *NativeTun) Name() (string, error) {
-	var ifName struct {
-		name [16]byte
-	}
-	ifNameSize := uintptr(16)
-
-	var errno syscall.Errno
+	var err error
 	tun.operateOnFd(func(fd uintptr) {
-		_, _, errno = unix.Syscall6(
-			unix.SYS_GETSOCKOPT,
-			fd,
+		tun.name, err = unix.GetsockoptString(
+			int(fd),
 			2, /* #define SYSPROTO_CONTROL 2 */
 			2, /* #define UTUN_OPT_IFNAME 2 */
-			uintptr(unsafe.Pointer(&ifName)),
-			uintptr(unsafe.Pointer(&ifNameSize)), 0)
+		)
 	})
 
-	if errno != 0 {
-		return "", fmt.Errorf("SYS_GETSOCKOPT: %v", errno)
+	if err != nil {
+		return "", fmt.Errorf("GetSockoptString: %w", err)
 	}
 
-	tun.name = string(ifName.name[:ifNameSize-1])
 	return tun.name, nil
 }
 
@@ -320,11 +272,6 @@ func (tun *NativeTun) Close() error {
 }
 
 func (tun *NativeTun) setMTU(n int) error {
-
-	// open datagram socket
-
-	var fd int
-
 	fd, err := unix.Socket(
 		unix.AF_INET,
 		unix.SOCK_DGRAM,
@@ -337,29 +284,18 @@ func (tun *NativeTun) setMTU(n int) error {
 
 	defer unix.Close(fd)
 
-	// do ioctl call
-
-	var ifr [32]byte
-	copy(ifr[:], tun.name)
-	*(*uint32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = uint32(n)
-	_, _, errno := unix.Syscall(
-		unix.SYS_IOCTL,
-		uintptr(fd),
-		uintptr(unix.SIOCSIFMTU),
-		uintptr(unsafe.Pointer(&ifr[0])),
-	)
-
-	if errno != 0 {
-		return fmt.Errorf("failed to set MTU on %s", tun.name)
+	var ifr unix.IfreqMTU
+	copy(ifr.Name[:], tun.name)
+	ifr.MTU = int32(n)
+	err = unix.IoctlSetIfreqMTU(fd, &ifr)
+	if err != nil {
+		return fmt.Errorf("failed to set MTU on %s: %w", tun.name, err)
 	}
 
 	return nil
 }
 
 func (tun *NativeTun) MTU() (int, error) {
-
-	// open datagram socket
-
 	fd, err := unix.Socket(
 		unix.AF_INET,
 		unix.SOCK_DGRAM,
@@ -372,19 +308,10 @@ func (tun *NativeTun) MTU() (int, error) {
 
 	defer unix.Close(fd)
 
-	// do ioctl call
-
-	var ifr [64]byte
-	copy(ifr[:], tun.name)
-	_, _, errno := unix.Syscall(
-		unix.SYS_IOCTL,
-		uintptr(fd),
-		uintptr(unix.SIOCGIFMTU),
-		uintptr(unsafe.Pointer(&ifr[0])),
-	)
-	if errno != 0 {
-		return 0, fmt.Errorf("failed to get MTU on %s", tun.name)
+	ifr, err := unix.IoctlGetIfreqMTU(fd, tun.name)
+	if err != nil {
+		return 0, fmt.Errorf("failed to get MTU on %s: %w", tun.name, err)
 	}
 
-	return int(*(*int32)(unsafe.Pointer(&ifr[16]))), nil
+	return int(ifr.MTU), nil
 }

tun/tun_freebsd.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
@@ -287,7 +287,7 @@ func CreateTUN(name string, mtu int) (Device, error) {
 	if errno != 0 {
 		tunFile.Close()
 		tunDestroy(assignedName)
-		return nil, fmt.Errorf("Unable to put into IFHEAD mode: %v", errno)
+		return nil, fmt.Errorf("Unable to put into IFHEAD mode: %w", errno)
 	}
 
 	// Open control sockets
@@ -328,7 +328,7 @@ func CreateTUN(name string, mtu int) (Device, error) {
 	if errno != 0 {
 		tunFile.Close()
 		tunDestroy(assignedName)
-		return nil, fmt.Errorf("Unable to get nd6 flags for %s: %v", assignedName, errno)
+		return nil, fmt.Errorf("Unable to get nd6 flags for %s: %w", assignedName, errno)
 	}
 	ndireq.Flags = ndireq.Flags &^ ND6_IFF_AUTO_LINKLOCAL
 	ndireq.Flags = ndireq.Flags | ND6_IFF_NO_DAD
@@ -341,7 +341,7 @@ func CreateTUN(name string, mtu int) (Device, error) {
 	if errno != 0 {
 		tunFile.Close()
 		tunDestroy(assignedName)
-		return nil, fmt.Errorf("Unable to set nd6 flags for %s: %v", assignedName, errno)
+		return nil, fmt.Errorf("Unable to set nd6 flags for %s: %w", assignedName, errno)
 	}
 
 	// Rename the interface
@@ -359,7 +359,7 @@ func CreateTUN(name string, mtu int) (Device, error) {
 	if errno != 0 {
 		tunFile.Close()
 		tunDestroy(assignedName)
-		return nil, fmt.Errorf("Failed to rename %s to %s: %v", assignedName, name, errno)
+		return nil, fmt.Errorf("Failed to rename %s to %s: %w", assignedName, name, errno)
 	}
 
 	return CreateTUNFromFile(tunFile, mtu)

tun/tun_linux.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
@@ -10,9 +10,7 @@ package tun
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
-	"net"
 	"os"
 	"sync"
 	"syscall"
@@ -21,6 +19,7 @@ import (
 
 	"golang.org/x/net/ipv6"
 	"golang.org/x/sys/unix"
+
 	"golang.zx2c4.com/wireguard/rwcancel"
 )
 
@@ -32,7 +31,6 @@ const (
 type NativeTun struct {
 	tunFile                 *os.File
 	index                   int32      // if index
-	name                    string     // name of interface
 	errors                  chan error // async error handling
 	events                  chan Event // device related events
 	nopi                    bool       // the device was passed IFF_NO_PI
@@ -40,6 +38,10 @@ type NativeTun struct {
 	netlinkCancel           *rwcancel.RWCancel
 	hackListenerClosed      sync.Mutex
 	statusListenersShutdown chan struct{}
+
+	nameOnce  sync.Once // guards calling initNameCache, which sets following fields
+	nameCache string    // name of interface
+	nameErr   error
 }
 
 func (tun *NativeTun) File() *os.File {
@@ -64,14 +66,19 @@ func (tun *NativeTun) routineHackListener() {
 		}
 		switch err {
 		case unix.EINVAL:
+			// If the tunnel is up, it reports that write() is
+			// allowed but we provided invalid data.
 			tun.events <- EventUp
 		case unix.EIO:
+			// If the tunnel is down, it reports that no I/O
+			// is possible, without checking our provided data.
 			tun.events <- EventDown
 		default:
 			return
 		}
 		select {
 		case <-time.After(time.Second):
+			// nothing
 		case <-tun.statusListenersShutdown:
 			return
 		}
@@ -85,7 +92,7 @@ func createNetlinkSocket() (int, error) {
 	}
 	saddr := &unix.SockaddrNetlink{
 		Family: unix.AF_NETLINK,
-		Groups: uint32((1 << (unix.RTNLGRP_LINK - 1)) | (1 << (unix.RTNLGRP_IPV4_IFADDR - 1)) | (1 << (unix.RTNLGRP_IPV6_IFADDR - 1))),
+		Groups: unix.RTMGRP_LINK | unix.RTMGRP_IPV4_IFADDR | unix.RTMGRP_IPV6_IFADDR,
 	}
 	err = unix.Bind(sock, saddr)
 	if err != nil {
@@ -99,10 +106,10 @@ func (tun *NativeTun) routineNetlinkListener() {
 		unix.Close(tun.netlinkSock)
 		tun.hackListenerClosed.Lock()
 		close(tun.events)
+		tun.netlinkCancel.Close()
 	}()
 
 	for msg := make([]byte, 1<<16); ; {
-
 		var err error
 		var msgn int
 		for {
@@ -111,12 +118,12 @@ func (tun *NativeTun) routineNetlinkListener() {
 				break
 			}
 			if !tun.netlinkCancel.ReadyRead() {
-				tun.errors <- fmt.Errorf("netlink socket closed: %s", err.Error())
+				tun.errors <- fmt.Errorf("netlink socket closed: %w", err)
 				return
 			}
 		}
 		if err != nil {
-			tun.errors <- fmt.Errorf("failed to receive netlink message: %s", err.Error())
+			tun.errors <- fmt.Errorf("failed to receive netlink message: %w", err)
 			return
 		}
 
@@ -126,6 +133,7 @@ func (tun *NativeTun) routineNetlinkListener() {
 		default:
 		}
 
+		wasEverUp := false
 		for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
 
 			hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
@@ -149,11 +157,17 @@ func (tun *NativeTun) routineNetlinkListener() {
 
 				if info.Flags&unix.IFF_RUNNING != 0 {
 					tun.events <- EventUp
+					wasEverUp = true
 				}
 
 				if info.Flags&unix.IFF_RUNNING == 0 {
+					// Don't emit EventDown before we've ever emitted EventUp.
+					// This avoids a startup race with HackListener, which
+					// might detect Up before we have finished reporting Down.
+					if wasEverUp {
 						tun.events <- EventDown
 					}
+				}
 
 				tun.events <- EventMTUUpdate
 
@@ -164,11 +178,6 @@ func (tun *NativeTun) routineNetlinkListener() {
 	}
 }
 
-func (tun *NativeTun) isUp() (bool, error) {
-	inter, err := net.InterfaceByName(tun.name)
-	return inter.Flags&net.FlagUp != 0, err
-}
-
 func getIFIndex(name string) (int32, error) {
 	fd, err := unix.Socket(
 		unix.AF_INET,
@@ -198,6 +207,11 @@ func getIFIndex(name string) (int32, error) {
 }
 
 func (tun *NativeTun) setMTU(n int) error {
+	name, err := tun.Name()
+	if err != nil {
+		return err
+	}
+
 	// open datagram socket
 	fd, err := unix.Socket(
 		unix.AF_INET,
@@ -212,9 +226,8 @@ func (tun *NativeTun) setMTU(n int) error {
 	defer unix.Close(fd)
 
 	// do ioctl call
-
 	var ifr [ifReqSize]byte
-	copy(ifr[:], tun.name)
+	copy(ifr[:], name)
 	*(*uint32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = uint32(n)
 	_, _, errno := unix.Syscall(
 		unix.SYS_IOCTL,
@@ -224,13 +237,18 @@ func (tun *NativeTun) setMTU(n int) error {
 	)
 
 	if errno != 0 {
-		return errors.New("failed to set MTU of TUN device")
+		return fmt.Errorf("failed to set MTU of TUN device: %w", errno)
 	}
 
 	return nil
 }
 
 func (tun *NativeTun) MTU() (int, error) {
+	name, err := tun.Name()
+	if err != nil {
+		return 0, err
+	}
+
 	// open datagram socket
 	fd, err := unix.Socket(
 		unix.AF_INET,
@@ -247,7 +265,7 @@ func (tun *NativeTun) MTU() (int, error) {
 	// do ioctl call
 
 	var ifr [ifReqSize]byte
-	copy(ifr[:], tun.name)
+	copy(ifr[:], name)
 	_, _, errno := unix.Syscall(
 		unix.SYS_IOCTL,
 		uintptr(fd),
@@ -255,13 +273,22 @@ func (tun *NativeTun) MTU() (int, error) {
 		uintptr(unsafe.Pointer(&ifr[0])),
 	)
 	if errno != 0 {
-		return 0, errors.New("failed to get MTU of TUN device: " + errno.Error())
+		return 0, fmt.Errorf("failed to get MTU of TUN device: %w", errno)
 	}
 
 	return int(*(*int32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ]))), nil
 }
 
 func (tun *NativeTun) Name() (string, error) {
+	tun.nameOnce.Do(tun.initNameCache)
+	return tun.nameCache, tun.nameErr
+}
+
+func (tun *NativeTun) initNameCache() {
+	tun.nameCache, tun.nameErr = tun.nameSlow()
+}
+
+func (tun *NativeTun) nameSlow() (string, error) {
 	sysconn, err := tun.tunFile.SyscallConn()
 	if err != nil {
 		return "", err
@@ -277,18 +304,16 @@ func (tun *NativeTun) Name() (string, error) {
 		)
 	})
 	if err != nil {
-		return "", errors.New("failed to get name of TUN device: " + err.Error())
+		return "", fmt.Errorf("failed to get name of TUN device: %w", err)
 	}
 	if errno != 0 {
-		return "", errors.New("failed to get name of TUN device: " + errno.Error())
+		return "", fmt.Errorf("failed to get name of TUN device: %w", errno)
 	}
-	nullStr := ifr[:]
-	i := bytes.IndexByte(nullStr, 0)
-	if i != -1 {
-		nullStr = nullStr[:i]
+	name := ifr[:]
+	if i := bytes.IndexByte(name, 0); i != -1 {
+		name = name[:i]
 	}
-	tun.name = string(nullStr)
-	return tun.name, nil
+	return string(name), nil
 }
 
 func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
@@ -367,6 +392,9 @@ func (tun *NativeTun) Close() error {
 func CreateTUN(name string, mtu int) (Device, error) {
 	nfd, err := unix.Open(cloneDevicePath, os.O_RDWR, 0)
 	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, fmt.Errorf("CreateTUN(%q) failed; %s does not exist", name, cloneDevicePath)
+		}
 		return nil, err
 	}
 
@@ -374,7 +402,7 @@ func CreateTUN(name string, mtu int) (Device, error) {
 	var flags uint16 = unix.IFF_TUN // | unix.IFF_NO_PI (disabled for TUN status hack)
 	nameBytes := []byte(name)
 	if len(nameBytes) >= unix.IFNAMSIZ {
-		return nil, errors.New("interface name too long")
+		return nil, fmt.Errorf("interface name too long: %w", unix.ENAMETOOLONG)
 	}
 	copy(ifr[:], nameBytes)
 	*(*uint16)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = flags
@@ -408,16 +436,15 @@ func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
 		statusListenersShutdown: make(chan struct{}),
 		nopi:                    false,
 	}
-	var err error
 
-	_, err = tun.Name()
+	name, err := tun.Name()
 	if err != nil {
 		return nil, err
 	}
 
 	// start event listener
 
-	tun.index, err = getIFIndex(tun.name)
+	tun.index, err = getIFIndex(name)
 	if err != nil {
 		return nil, err
 	}

tun/tun_openbsd.go

@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -99,16 +100,6 @@ func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 	}
 }
 
-func errorIsEBUSY(err error) bool {
-	if pe, ok := err.(*os.PathError); ok {
-		err = pe.Err
-	}
-	if errno, ok := err.(syscall.Errno); ok && errno == syscall.EBUSY {
-		return true
-	}
-	return false
-}
-
 func CreateTUN(name string, mtu int) (Device, error) {
 	ifIndex := -1
 	if name != "tun" {
@@ -124,9 +115,9 @@ func CreateTUN(name string, mtu int) (Device, error) {
 	if ifIndex != -1 {
 		tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR, 0)
 	} else {
-		for ifIndex = 0; ifIndex < 256; ifIndex += 1 {
+		for ifIndex = 0; ifIndex < 256; ifIndex++ {
 			tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR, 0)
-			if err == nil || !errorIsEBUSY(err) {
+			if err == nil || !errors.Is(err, syscall.EBUSY) {
 				break
 			}
 		}

tun/tun_windows.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: MIT
  *
- * Copyright (C) 2018-2019 WireGuard LLC. All Rights Reserved.
+ * Copyright (C) 2018-2021 WireGuard LLC. All Rights Reserved.
  */
 
 package tun
@@ -8,11 +8,11 @@ package tun
 import (
 	"errors"
 	"fmt"
+	"log"
 	"os"
-	"sync"
 	"sync/atomic"
 	"time"
-	"unsafe"
+	_ "unsafe"
 
 	"golang.org/x/sys/windows"
 
@@ -33,18 +33,19 @@ type rateJuggler struct {
 }
 
 type NativeTun struct {
-	wt        *wintun.Interface
+	wt        *wintun.Adapter
 	handle    windows.Handle
 	close     bool
 	events    chan Event
 	errors    chan error
 	forcedMTU int
 	rate      rateJuggler
-	rings     *wintun.RingDescriptor
-	writeLock sync.Mutex
+	session   wintun.Session
+	readWait  windows.Handle
 }
 
-const WintunPool = wintun.Pool("WireGuard")
+var WintunPool, _ = wintun.MakePool("WireGuard")
+var WintunStaticRequestedGUID *windows.GUID
 
 //go:linkname procyield runtime.procyield
 func procyield(cycles uint32)
@@ -57,7 +58,7 @@ func nanotime() int64
 // interface with the same name exist, it is reused.
 //
 func CreateTUN(ifname string, mtu int) (Device, error) {
-	return CreateTUNWithRequestedGUID(ifname, nil, mtu)
+	return CreateTUNWithRequestedGUID(ifname, WintunStaticRequestedGUID, mtu)
 }
 
 //
@@ -66,20 +67,23 @@ func CreateTUN(ifname string, mtu int) (Device, error) {
 //
 func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu int) (Device, error) {
 	var err error
-	var wt *wintun.Interface
+	var wt *wintun.Adapter
 
 	// Does an interface with this name already exist?
-	wt, err = WintunPool.GetInterface(ifname)
+	wt, err = WintunPool.OpenAdapter(ifname)
 	if err == nil {
 		// If so, we delete it, in case it has weird residual configuration.
-		_, err = wt.DeleteInterface()
+		_, err = wt.Delete(true)
 		if err != nil {
-			return nil, fmt.Errorf("Error deleting already existing interface: %v", err)
+			return nil, fmt.Errorf("Error deleting already existing interface: %w", err)
 		}
 	}
-	wt, _, err = WintunPool.CreateInterface(ifname, requestedGUID)
+	wt, rebootRequired, err := WintunPool.CreateAdapter(ifname, requestedGUID)
 	if err != nil {
-		return nil, fmt.Errorf("Error creating interface: %v", err)
+		return nil, fmt.Errorf("Error creating interface: %w", err)
+	}
+	if rebootRequired {
+		log.Println("Windows indicated a reboot is required.")
 	}
 
 	forcedMTU := 1420
@@ -95,17 +99,13 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu
 		forcedMTU: forcedMTU,
 	}
 
-	tun.rings, err = wintun.NewRingDescriptor()
+	tun.session, err = wt.StartSession(0x800000) // Ring capacity, 8 MiB
 	if err != nil {
-		tun.Close()
-		return nil, fmt.Errorf("Error creating events: %v", err)
-	}
-
-	tun.handle, err = tun.wt.Register(tun.rings)
-	if err != nil {
-		tun.Close()
-		return nil, fmt.Errorf("Error registering rings: %v", err)
+		tun.wt.Delete(false)
+		close(tun.events)
+		return nil, fmt.Errorf("Error starting session: %w", err)
 	}
+	tun.readWait = tun.session.ReadWaitEvent()
 	return tun, nil
 }
 
@@ -123,16 +123,10 @@ func (tun *NativeTun) Events() chan Event {
 
 func (tun *NativeTun) Close() error {
 	tun.close = true
-	if tun.rings.Send.TailMoved != 0 {
-		windows.SetEvent(tun.rings.Send.TailMoved) // wake the reader if it's sleeping
-	}
-	if tun.handle != windows.InvalidHandle {
-		windows.CloseHandle(tun.handle)
-	}
-	tun.rings.Close()
+	tun.session.End()
 	var err error
 	if tun.wt != nil {
-		_, err = tun.wt.DeleteInterface()
+		_, err = tun.wt.Delete(false)
 	}
 	close(tun.events)
 	return err
@@ -156,56 +150,34 @@ retry:
 		return 0, err
 	default:
 	}
-	if tun.close {
-		return 0, os.ErrClosed
-	}
-
-	buffHead := atomic.LoadUint32(&tun.rings.Send.Ring.Head)
-	if buffHead >= wintun.PacketCapacity {
-		return 0, os.ErrClosed
-	}
-
 	start := nanotime()
 	shouldSpin := atomic.LoadUint64(&tun.rate.current) >= spinloopRateThreshold && uint64(start-atomic.LoadInt64(&tun.rate.nextStartTime)) <= rateMeasurementGranularity*2
-	var buffTail uint32
 	for {
-		buffTail = atomic.LoadUint32(&tun.rings.Send.Ring.Tail)
-		if buffHead != buffTail {
-			break
-		}
 		if tun.close {
 			return 0, os.ErrClosed
 		}
+		packet, err := tun.session.ReceivePacket()
+		switch err {
+		case nil:
+			packetSize := len(packet)
+			copy(buff[offset:], packet)
+			tun.session.ReleaseReceivePacket(packet)
+			tun.rate.update(uint64(packetSize))
+			return packetSize, nil
+		case windows.ERROR_NO_MORE_ITEMS:
 			if !shouldSpin || uint64(nanotime()-start) >= spinloopDuration {
-			windows.WaitForSingleObject(tun.rings.Send.TailMoved, windows.INFINITE)
+				windows.WaitForSingleObject(tun.readWait, windows.INFINITE)
 				goto retry
 			}
 			procyield(1)
-	}
-	if buffTail >= wintun.PacketCapacity {
+			continue
+		case windows.ERROR_HANDLE_EOF:
 			return 0, os.ErrClosed
+		case windows.ERROR_INVALID_DATA:
+			return 0, errors.New("Send ring corrupt")
 		}
-
-	buffContent := tun.rings.Send.Ring.Wrap(buffTail - buffHead)
-	if buffContent < uint32(unsafe.Sizeof(wintun.PacketHeader{})) {
-		return 0, errors.New("incomplete packet header in send ring")
+		return 0, fmt.Errorf("Read failed: %w", err)
 	}
-
-	packet := (*wintun.Packet)(unsafe.Pointer(&tun.rings.Send.Ring.Data[buffHead]))
-	if packet.Size > wintun.PacketSizeMax {
-		return 0, errors.New("packet too big in send ring")
-	}
-
-	alignedPacketSize := wintun.PacketAlign(uint32(unsafe.Sizeof(wintun.PacketHeader{})) + packet.Size)
-	if alignedPacketSize > buffContent {
-		return 0, errors.New("incomplete packet in send ring")
-	}
-
-	copy(buff[offset:], packet.Data[:packet.Size])
-	buffHead = tun.rings.Send.Ring.Wrap(buffHead + alignedPacketSize)
-	atomic.StoreUint32(&tun.rings.Send.Ring.Head, buffHead)
-	tun.rate.update(uint64(packet.Size))
-	return int(packet.Size), nil
 }
 
 func (tun *NativeTun) Flush() error {
@@ -217,36 +189,22 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
 		return 0, os.ErrClosed
 	}
 
-	packetSize := uint32(len(buff) - offset)
+	packetSize := len(buff) - offset
 	tun.rate.update(uint64(packetSize))
-	alignedPacketSize := wintun.PacketAlign(uint32(unsafe.Sizeof(wintun.PacketHeader{})) + packetSize)
 
-	tun.writeLock.Lock()
-	defer tun.writeLock.Unlock()
-
-	buffHead := atomic.LoadUint32(&tun.rings.Receive.Ring.Head)
-	if buffHead >= wintun.PacketCapacity {
-		return 0, os.ErrClosed
+	packet, err := tun.session.AllocateSendPacket(packetSize)
+	if err == nil {
+		copy(packet, buff[offset:])
+		tun.session.SendPacket(packet)
+		return packetSize, nil
 	}
-
-	buffTail := atomic.LoadUint32(&tun.rings.Receive.Ring.Tail)
-	if buffTail >= wintun.PacketCapacity {
+	switch err {
+	case windows.ERROR_HANDLE_EOF:
 		return 0, os.ErrClosed
-	}
-
-	buffSpace := tun.rings.Receive.Ring.Wrap(buffHead - buffTail - wintun.PacketAlignment)
-	if alignedPacketSize > buffSpace {
+	case windows.ERROR_BUFFER_OVERFLOW:
 		return 0, nil // Dropping when ring is full.
 	}
-
-	packet := (*wintun.Packet)(unsafe.Pointer(&tun.rings.Receive.Ring.Data[buffTail]))
-	packet.Size = packetSize
-	copy(packet.Data[:packetSize], buff[offset:])
-	atomic.StoreUint32(&tun.rings.Receive.Ring.Tail, tun.rings.Receive.Ring.Wrap(buffTail+alignedPacketSize))
-	if atomic.LoadInt32(&tun.rings.Receive.Ring.Alertable) != 0 {
-		windows.SetEvent(tun.rings.Receive.TailMoved)
-	}
-	return int(packetSize), nil
+	return 0, fmt.Errorf("Write failed: %w", err)
 }
 
 // LUID returns Windows interface instance ID.
@@ -254,9 +212,9 @@ func (tun *NativeTun) LUID() uint64 {
 	return tun.wt.LUID()
 }
 
-// Version returns the version of the Wintun driver and NDIS system currently loaded.
-func (tun *NativeTun) Version() (driverVersion string, ndisVersion string, err error) {
-	return tun.wt.Version()
+// RunningVersion returns the running version of the Wintun driver.
+func (tun *NativeTun) RunningVersion() (version uint32, err error) {
+	return wintun.RunningVersion()
 }
 
 func (rate *rateJuggler) update(packetLen uint64) {

tun/tuntest/tuntest.go

@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package tuntest
+
+import (
+	"encoding/binary"
+	"io"
+	"net"
+	"os"
+
+	"golang.zx2c4.com/wireguard/tun"
+)
+
+func Ping(dst, src net.IP) []byte {
+	localPort := uint16(1337)
+	seq := uint16(0)
+
+	payload := make([]byte, 4)
+	binary.BigEndian.PutUint16(payload[0:], localPort)
+	binary.BigEndian.PutUint16(payload[2:], seq)
+
+	return genICMPv4(payload, dst, src)
+}
+
+// Checksum is the "internet checksum" from https://tools.ietf.org/html/rfc1071.
+func checksum(buf []byte, initial uint16) uint16 {
+	v := uint32(initial)
+	for i := 0; i < len(buf)-1; i += 2 {
+		v += uint32(binary.BigEndian.Uint16(buf[i:]))
+	}
+	if len(buf)%2 == 1 {
+		v += uint32(buf[len(buf)-1]) << 8
+	}
+	for v > 0xffff {
+		v = (v >> 16) + (v & 0xffff)
+	}
+	return ^uint16(v)
+}
+
+func genICMPv4(payload []byte, dst, src net.IP) []byte {
+	const (
+		icmpv4ProtocolNumber = 1
+		icmpv4Echo           = 8
+		icmpv4ChecksumOffset = 2
+		icmpv4Size           = 8
+		ipv4Size             = 20
+		ipv4TotalLenOffset   = 2
+		ipv4ChecksumOffset   = 10
+		ttl                  = 65
+		headerSize           = ipv4Size + icmpv4Size
+	)
+
+	pkt := make([]byte, headerSize+len(payload))
+
+	ip := pkt[0:ipv4Size]
+	icmpv4 := pkt[ipv4Size : ipv4Size+icmpv4Size]
+
+	// https://tools.ietf.org/html/rfc792
+	icmpv4[0] = icmpv4Echo // type
+	icmpv4[1] = 0          // code
+	chksum := ^checksum(icmpv4, checksum(payload, 0))
+	binary.BigEndian.PutUint16(icmpv4[icmpv4ChecksumOffset:], chksum)
+
+	// https://tools.ietf.org/html/rfc760 section 3.1
+	length := uint16(len(pkt))
+	ip[0] = (4 << 4) | (ipv4Size / 4)
+	binary.BigEndian.PutUint16(ip[ipv4TotalLenOffset:], length)
+	ip[8] = ttl
+	ip[9] = icmpv4ProtocolNumber
+	copy(ip[12:], src.To4())
+	copy(ip[16:], dst.To4())
+	chksum = ^checksum(ip[:], 0)
+	binary.BigEndian.PutUint16(ip[ipv4ChecksumOffset:], chksum)
+
+	copy(pkt[headerSize:], payload)
+	return pkt
+}
+
+// TODO(crawshaw): find a reusable home for this. package devicetest?
+type ChannelTUN struct {
+	Inbound  chan []byte // incoming packets, closed on TUN close
+	Outbound chan []byte // outbound packets, blocks forever on TUN close
+
+	closed chan struct{}
+	events chan tun.Event
+	tun    chTun
+}
+
+func NewChannelTUN() *ChannelTUN {
+	c := &ChannelTUN{
+		Inbound:  make(chan []byte),
+		Outbound: make(chan []byte),
+		closed:   make(chan struct{}),
+		events:   make(chan tun.Event, 1),
+	}
+	c.tun.c = c
+	c.events <- tun.EventUp
+	return c
+}
+
+func (c *ChannelTUN) TUN() tun.Device {
+	return &c.tun
+}
+
+type chTun struct {
+	c *ChannelTUN
+}
+
+func (t *chTun) File() *os.File { return nil }
+
+func (t *chTun) Read(data []byte, offset int) (int, error) {
+	select {
+	case <-t.c.closed:
+		return 0, io.EOF // TODO(crawshaw): what is the correct error value?
+	case msg := <-t.c.Outbound:
+		return copy(data[offset:], msg), nil
+	}
+}
+
+// Write is called by the wireguard device to deliver a packet for routing.
+func (t *chTun) Write(data []byte, offset int) (int, error) {
+	if offset == -1 {
+		close(t.c.closed)
+		close(t.c.events)
+		return 0, io.EOF
+	}
+	msg := make([]byte, len(data)-offset)
+	copy(msg, data[offset:])
+	select {
+	case <-t.c.closed:
+		return 0, io.EOF // TODO(crawshaw): what is the correct error value?
+	case t.c.Inbound <- msg:
+		return len(data) - offset, nil
+	}
+}
+
+const DefaultMTU = 1420
+
+func (t *chTun) Flush() error           { return nil }
+func (t *chTun) MTU() (int, error)      { return DefaultMTU, nil }
+func (t *chTun) Name() (string, error)  { return "loopbackTun1", nil }
+func (t *chTun) Events() chan tun.Event { return t.c.events }
+func (t *chTun) Close() error {
+	t.Write(nil, -1)
+	return nil
+}

tun/wintun/dll_fromfile_windows.go

@@ -0,0 +1,54 @@
+// +build !load_wintun_from_rsrc
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package wintun
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+type lazyDLL struct {
+	Name   string
+	mu     sync.Mutex
+	module windows.Handle
+	onLoad func(d *lazyDLL)
+}
+
+func (d *lazyDLL) Load() error {
+	if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&d.module))) != nil {
+		return nil
+	}
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.module != 0 {
+		return nil
+	}
+
+	const (
+		LOAD_LIBRARY_SEARCH_APPLICATION_DIR = 0x00000200
+		LOAD_LIBRARY_SEARCH_SYSTEM32        = 0x00000800
+	)
+	module, err := windows.LoadLibraryEx(d.Name, 0, LOAD_LIBRARY_SEARCH_APPLICATION_DIR|LOAD_LIBRARY_SEARCH_SYSTEM32)
+	if err != nil {
+		return fmt.Errorf("Unable to load library: %w", err)
+	}
+
+	atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&d.module)), unsafe.Pointer(module))
+	if d.onLoad != nil {
+		d.onLoad(d)
+	}
+	return nil
+}
+
+func (p *lazyProc) nameToAddr() (uintptr, error) {
+	return windows.GetProcAddress(p.dll.module, p.Name)
+}

tun/wintun/dll_fromrsrc_windows.go

@@ -0,0 +1,62 @@
+// +build load_wintun_from_rsrc
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package wintun
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+
+	"golang.zx2c4.com/wireguard/tun/wintun/memmod"
+	"golang.zx2c4.com/wireguard/tun/wintun/resource"
+)
+
+type lazyDLL struct {
+	Name   string
+	mu     sync.Mutex
+	module *memmod.Module
+	onLoad func(d *lazyDLL)
+}
+
+func (d *lazyDLL) Load() error {
+	if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&d.module))) != nil {
+		return nil
+	}
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.module != nil {
+		return nil
+	}
+
+	const ourModule windows.Handle = 0
+	resInfo, err := resource.FindByName(ourModule, d.Name, resource.RT_RCDATA)
+	if err != nil {
+		return fmt.Errorf("Unable to find \"%v\" RCDATA resource: %w", d.Name, err)
+	}
+	data, err := resource.Load(ourModule, resInfo)
+	if err != nil {
+		return fmt.Errorf("Unable to load resource: %w", err)
+	}
+	module, err := memmod.LoadLibrary(data)
+	if err != nil {
+		return fmt.Errorf("Unable to load library: %w", err)
+	}
+
+	atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&d.module)), unsafe.Pointer(module))
+	if d.onLoad != nil {
+		d.onLoad(d)
+	}
+	return nil
+}
+
+func (p *lazyProc) nameToAddr() (uintptr, error) {
+	return p.dll.module.ProcAddressByName(p.Name)
+}

tun/wintun/dll_windows.go

@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package wintun
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"unsafe"
+)
+
+func newLazyDLL(name string, onLoad func(d *lazyDLL)) *lazyDLL {
+	return &lazyDLL{Name: name, onLoad: onLoad}
+}
+
+func (d *lazyDLL) NewProc(name string) *lazyProc {
+	return &lazyProc{dll: d, Name: name}
+}
+
+type lazyProc struct {
+	Name string
+	mu   sync.Mutex
+	dll  *lazyDLL
+	addr uintptr
+}
+
+func (p *lazyProc) Find() error {
+	if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&p.addr))) != nil {
+		return nil
+	}
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.addr != 0 {
+		return nil
+	}
+
+	err := p.dll.Load()
+	if err != nil {
+		return fmt.Errorf("Error loading %v DLL: %w", p.dll.Name, err)
+	}
+	addr, err := p.nameToAddr()
+	if err != nil {
+		return fmt.Errorf("Error getting %v address: %w", p.Name, err)
+	}
+
+	atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&p.addr)), unsafe.Pointer(addr))
+	return nil
+}
+
+func (p *lazyProc) Addr() uintptr {
+	err := p.Find()
+	if err != nil {
+		panic(err)
+	}
+	return p.addr
+}

tun/wintun/iphlpapi/conversion_windows.go

@@ -1,25 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
- */
-
-package iphlpapi
-
-import "golang.org/x/sys/windows"
-
-//sys	convertInterfaceLUIDToGUID(interfaceLUID *uint64, interfaceGUID *windows.GUID) (ret error) = iphlpapi.ConvertInterfaceLuidToGuid
-//sys	convertInterfaceAliasToLUID(interfaceAlias *uint16, interfaceLUID *uint64) (ret error) = iphlpapi.ConvertInterfaceAliasToLuid
-
-func InterfaceGUIDFromAlias(alias string) (*windows.GUID, error) {
-	var luid uint64
-	var guid windows.GUID
-	err := convertInterfaceAliasToLUID(windows.StringToUTF16Ptr(alias), &luid)
-	if err != nil {
-		return nil, err
-	}
-	err = convertInterfaceLUIDToGUID(&luid, &guid)
-	if err != nil {
-		return nil, err
-	}
-	return &guid, nil
-}

tun/wintun/iphlpapi/mksyscall.go

@@ -1,8 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
- */
-
-package iphlpapi
-
-//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go conversion_windows.go

tun/wintun/iphlpapi/zsyscall_windows.go

@@ -1,60 +0,0 @@
-// Code generated by 'go generate'; DO NOT EDIT.
-
-package iphlpapi
-
-import (
-	"syscall"
-	"unsafe"
-
-	"golang.org/x/sys/windows"
-)
-
-var _ unsafe.Pointer
-
-// Do the interface allocations only once for common
-// Errno values.
-const (
-	errnoERROR_IO_PENDING = 997
-)
-
-var (
-	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
-)
-
-// errnoErr returns common boxed Errno values, to prevent
-// allocations at runtime.
-func errnoErr(e syscall.Errno) error {
-	switch e {
-	case 0:
-		return nil
-	case errnoERROR_IO_PENDING:
-		return errERROR_IO_PENDING
-	}
-	// TODO: add more here, after collecting data on the common
-	// error values see on Windows. (perhaps when running
-	// all.bat?)
-	return e
-}
-
-var (
-	modiphlpapi = windows.NewLazySystemDLL("iphlpapi.dll")
-
-	procConvertInterfaceLuidToGuid  = modiphlpapi.NewProc("ConvertInterfaceLuidToGuid")
-	procConvertInterfaceAliasToLuid = modiphlpapi.NewProc("ConvertInterfaceAliasToLuid")
-)
-
-func convertInterfaceLUIDToGUID(interfaceLUID *uint64, interfaceGUID *windows.GUID) (ret error) {
-	r0, _, _ := syscall.Syscall(procConvertInterfaceLuidToGuid.Addr(), 2, uintptr(unsafe.Pointer(interfaceLUID)), uintptr(unsafe.Pointer(interfaceGUID)), 0)
-	if r0 != 0 {
-		ret = syscall.Errno(r0)
-	}
-	return
-}
-
-func convertInterfaceAliasToLUID(interfaceAlias *uint16, interfaceLUID *uint64) (ret error) {
-	r0, _, _ := syscall.Syscall(procConvertInterfaceAliasToLuid.Addr(), 2, uintptr(unsafe.Pointer(interfaceAlias)), uintptr(unsafe.Pointer(interfaceLUID)), 0)
-	if r0 != 0 {
-		ret = syscall.Errno(r0)
-	}
-	return
-}

tun/wintun/memmod/memmod_windows.go

@@ -0,0 +1,620 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package memmod
+
+import (
+	"errors"
+	"fmt"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+type addressList struct {
+	next    *addressList
+	address uintptr
+}
+
+func (head *addressList) free() {
+	for node := head; node != nil; node = node.next {
+		windows.VirtualFree(node.address, 0, windows.MEM_RELEASE)
+	}
+}
+
+type Module struct {
+	headers       *IMAGE_NT_HEADERS
+	codeBase      uintptr
+	modules       []windows.Handle
+	initialized   bool
+	isDLL         bool
+	isRelocated   bool
+	nameExports   map[string]uint16
+	entry         uintptr
+	blockedMemory *addressList
+}
+
+func (module *Module) headerDirectory(idx int) *IMAGE_DATA_DIRECTORY {
+	return &module.headers.OptionalHeader.DataDirectory[idx]
+}
+
+func (module *Module) copySections(address uintptr, size uintptr, old_headers *IMAGE_NT_HEADERS) error {
+	sections := module.headers.Sections()
+	for i := range sections {
+		if sections[i].SizeOfRawData == 0 {
+			// Section doesn't contain data in the dll itself, but may define uninitialized data.
+			sectionSize := old_headers.OptionalHeader.SectionAlignment
+			if sectionSize == 0 {
+				continue
+			}
+			dest, err := windows.VirtualAlloc(module.codeBase+uintptr(sections[i].VirtualAddress),
+				uintptr(sectionSize),
+				windows.MEM_COMMIT,
+				windows.PAGE_READWRITE)
+			if err != nil {
+				return fmt.Errorf("Error allocating section: %w", err)
+			}
+
+			// Always use position from file to support alignments smaller than page size (allocation above will align to page size).
+			dest = module.codeBase + uintptr(sections[i].VirtualAddress)
+			// NOTE: On 64bit systems we truncate to 32bit here but expand again later when "PhysicalAddress" is used.
+			sections[i].SetPhysicalAddress((uint32)(dest & 0xffffffff))
+			var dst []byte
+			unsafeSlice(unsafe.Pointer(&dst), a2p(dest), int(sectionSize))
+			for j := range dst {
+				dst[j] = 0
+			}
+			continue
+		}
+
+		if size < uintptr(sections[i].PointerToRawData+sections[i].SizeOfRawData) {
+			return errors.New("Incomplete section")
+		}
+
+		// Commit memory block and copy data from dll.
+		dest, err := windows.VirtualAlloc(module.codeBase+uintptr(sections[i].VirtualAddress),
+			uintptr(sections[i].SizeOfRawData),
+			windows.MEM_COMMIT,
+			windows.PAGE_READWRITE)
+		if err != nil {
+			return fmt.Errorf("Error allocating memory block: %w", err)
+		}
+
+		// Always use position from file to support alignments smaller than page size (allocation above will align to page size).
+		memcpy(
+			module.codeBase+uintptr(sections[i].VirtualAddress),
+			address+uintptr(sections[i].PointerToRawData),
+			uintptr(sections[i].SizeOfRawData))
+		// NOTE: On 64bit systems we truncate to 32bit here but expand again later when "PhysicalAddress" is used.
+		sections[i].SetPhysicalAddress((uint32)(dest & 0xffffffff))
+	}
+
+	return nil
+}
+
+func (module *Module) realSectionSize(section *IMAGE_SECTION_HEADER) uintptr {
+	size := section.SizeOfRawData
+	if size != 0 {
+		return uintptr(size)
+	}
+	if (section.Characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA) != 0 {
+		return uintptr(module.headers.OptionalHeader.SizeOfInitializedData)
+	}
+	if (section.Characteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA) != 0 {
+		return uintptr(module.headers.OptionalHeader.SizeOfUninitializedData)
+	}
+	return 0
+}
+
+type sectionFinalizeData struct {
+	address         uintptr
+	alignedAddress  uintptr
+	size            uintptr
+	characteristics uint32
+	last            bool
+}
+
+func (module *Module) finalizeSection(sectionData *sectionFinalizeData) error {
+	if sectionData.size == 0 {
+		return nil
+	}
+
+	if (sectionData.characteristics & IMAGE_SCN_MEM_DISCARDABLE) != 0 {
+		// Section is not needed any more and can safely be freed.
+		if sectionData.address == sectionData.alignedAddress &&
+			(sectionData.last ||
+				(sectionData.size%uintptr(module.headers.OptionalHeader.SectionAlignment)) == 0) {
+			// Only allowed to decommit whole pages.
+			windows.VirtualFree(sectionData.address, sectionData.size, windows.MEM_DECOMMIT)
+		}
+		return nil
+	}
+
+	// determine protection flags based on characteristics
+	var ProtectionFlags = [8]uint32{
+		windows.PAGE_NOACCESS,          // not writeable, not readable, not executable
+		windows.PAGE_EXECUTE,           // not writeable, not readable, executable
+		windows.PAGE_READONLY,          // not writeable, readable, not executable
+		windows.PAGE_EXECUTE_READ,      // not writeable, readable, executable
+		windows.PAGE_WRITECOPY,         // writeable, not readable, not executable
+		windows.PAGE_EXECUTE_WRITECOPY, // writeable, not readable, executable
+		windows.PAGE_READWRITE,         // writeable, readable, not executable
+		windows.PAGE_EXECUTE_READWRITE, // writeable, readable, executable
+	}
+	protect := ProtectionFlags[sectionData.characteristics>>29]
+	if (sectionData.characteristics & IMAGE_SCN_MEM_NOT_CACHED) != 0 {
+		protect |= windows.PAGE_NOCACHE
+	}
+
+	// Change memory access flags.
+	var oldProtect uint32
+	err := windows.VirtualProtect(sectionData.address, sectionData.size, protect, &oldProtect)
+	if err != nil {
+		return fmt.Errorf("Error protecting memory page: %w", err)
+	}
+
+	return nil
+}
+
+func (module *Module) finalizeSections() error {
+	sections := module.headers.Sections()
+	imageOffset := module.headers.OptionalHeader.imageOffset()
+	sectionData := sectionFinalizeData{}
+	sectionData.address = uintptr(sections[0].PhysicalAddress()) | imageOffset
+	sectionData.alignedAddress = alignDown(sectionData.address, uintptr(module.headers.OptionalHeader.SectionAlignment))
+	sectionData.size = module.realSectionSize(&sections[0])
+	sectionData.characteristics = sections[0].Characteristics
+
+	// Loop through all sections and change access flags.
+	for i := uint16(1); i < module.headers.FileHeader.NumberOfSections; i++ {
+		sectionAddress := uintptr(sections[i].PhysicalAddress()) | imageOffset
+		alignedAddress := alignDown(sectionAddress, uintptr(module.headers.OptionalHeader.SectionAlignment))
+		sectionSize := module.realSectionSize(&sections[i])
+		// Combine access flags of all sections that share a page.
+		// TODO: We currently share flags of a trailing large section with the page of a first small section. This should be optimized.
+		if sectionData.alignedAddress == alignedAddress || sectionData.address+sectionData.size > alignedAddress {
+			// Section shares page with previous.
+			if (sections[i].Characteristics&IMAGE_SCN_MEM_DISCARDABLE) == 0 || (sectionData.characteristics&IMAGE_SCN_MEM_DISCARDABLE) == 0 {
+				sectionData.characteristics = (sectionData.characteristics | sections[i].Characteristics) &^ IMAGE_SCN_MEM_DISCARDABLE
+			} else {
+				sectionData.characteristics |= sections[i].Characteristics
+			}
+			sectionData.size = sectionAddress + sectionSize - sectionData.address
+			continue
+		}
+
+		err := module.finalizeSection(&sectionData)
+		if err != nil {
+			return fmt.Errorf("Error finalizing section: %w", err)
+		}
+		sectionData.address = sectionAddress
+		sectionData.alignedAddress = alignedAddress
+		sectionData.size = sectionSize
+		sectionData.characteristics = sections[i].Characteristics
+	}
+	sectionData.last = true
+	err := module.finalizeSection(&sectionData)
+	if err != nil {
+		return fmt.Errorf("Error finalizing section: %w", err)
+	}
+	return nil
+}
+
+func (module *Module) executeTLS() {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_TLS)
+	if directory.VirtualAddress == 0 {
+		return
+	}
+
+	tls := (*IMAGE_TLS_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	callback := tls.AddressOfCallbacks
+	if callback != 0 {
+		for {
+			f := *(*uintptr)(a2p(callback))
+			if f == 0 {
+				break
+			}
+			syscall.Syscall(f, 3, module.codeBase, uintptr(DLL_PROCESS_ATTACH), uintptr(0))
+			callback += unsafe.Sizeof(f)
+		}
+	}
+}
+
+func (module *Module) performBaseRelocation(delta uintptr) (relocated bool, err error) {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_BASERELOC)
+	if directory.Size == 0 {
+		return delta == 0, nil
+	}
+
+	relocationHdr := (*IMAGE_BASE_RELOCATION)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	for relocationHdr.VirtualAddress > 0 {
+		dest := module.codeBase + uintptr(relocationHdr.VirtualAddress)
+
+		var relInfos []uint16
+		unsafeSlice(
+			unsafe.Pointer(&relInfos),
+			a2p(uintptr(unsafe.Pointer(relocationHdr))+unsafe.Sizeof(*relocationHdr)),
+			int((uintptr(relocationHdr.SizeOfBlock)-unsafe.Sizeof(*relocationHdr))/unsafe.Sizeof(relInfos[0])))
+		for _, relInfo := range relInfos {
+			// The upper 4 bits define the type of relocation.
+			relType := relInfo >> 12
+			// The lower 12 bits define the offset.
+			relOffset := uintptr(relInfo & 0xfff)
+
+			switch relType {
+			case IMAGE_REL_BASED_ABSOLUTE:
+				// Skip relocation.
+
+			case IMAGE_REL_BASED_LOW:
+				*(*uint16)(a2p(dest + relOffset)) += uint16(delta & 0xffff)
+				break
+
+			case IMAGE_REL_BASED_HIGH:
+				*(*uint16)(a2p(dest + relOffset)) += uint16(uint32(delta) >> 16)
+				break
+
+			case IMAGE_REL_BASED_HIGHLOW:
+				*(*uint32)(a2p(dest + relOffset)) += uint32(delta)
+
+			case IMAGE_REL_BASED_DIR64:
+				*(*uint64)(a2p(dest + relOffset)) += uint64(delta)
+
+			case IMAGE_REL_BASED_THUMB_MOV32:
+				inst := *(*uint32)(a2p(dest + relOffset))
+				imm16 := ((inst << 1) & 0x0800) + ((inst << 12) & 0xf000) +
+					((inst >> 20) & 0x0700) + ((inst >> 16) & 0x00ff)
+				if (inst & 0x8000fbf0) != 0x0000f240 {
+					return false, fmt.Errorf("Wrong Thumb2 instruction %08x, expected MOVW", inst)
+				}
+				imm16 += uint32(delta) & 0xffff
+				hiDelta := (uint32(delta&0xffff0000) >> 16) + ((imm16 & 0xffff0000) >> 16)
+				*(*uint32)(a2p(dest + relOffset)) = (inst & 0x8f00fbf0) + ((imm16 >> 1) & 0x0400) +
+					((imm16 >> 12) & 0x000f) +
+					((imm16 << 20) & 0x70000000) +
+					((imm16 << 16) & 0xff0000)
+				if hiDelta != 0 {
+					inst = *(*uint32)(a2p(dest + relOffset + 4))
+					imm16 = ((inst << 1) & 0x0800) + ((inst << 12) & 0xf000) +
+						((inst >> 20) & 0x0700) + ((inst >> 16) & 0x00ff)
+					if (inst & 0x8000fbf0) != 0x0000f2c0 {
+						return false, fmt.Errorf("Wrong Thumb2 instruction %08x, expected MOVT", inst)
+					}
+					imm16 += hiDelta
+					if imm16 > 0xffff {
+						return false, fmt.Errorf("Resulting immediate value won't fit: %08x", imm16)
+					}
+					*(*uint32)(a2p(dest + relOffset + 4)) = (inst & 0x8f00fbf0) +
+						((imm16 >> 1) & 0x0400) +
+						((imm16 >> 12) & 0x000f) +
+						((imm16 << 20) & 0x70000000) +
+						((imm16 << 16) & 0xff0000)
+				}
+
+			default:
+				return false, fmt.Errorf("Unsupported relocation: %v", relType)
+			}
+		}
+
+		// Advance to next relocation block.
+		relocationHdr = (*IMAGE_BASE_RELOCATION)(a2p(uintptr(unsafe.Pointer(relocationHdr)) + uintptr(relocationHdr.SizeOfBlock)))
+	}
+	return true, nil
+}
+
+func (module *Module) buildImportTable() error {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_IMPORT)
+	if directory.Size == 0 {
+		return nil
+	}
+
+	module.modules = make([]windows.Handle, 0, 16)
+	importDesc := (*IMAGE_IMPORT_DESCRIPTOR)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	for !isBadReadPtr(uintptr(unsafe.Pointer(importDesc)), unsafe.Sizeof(*importDesc)) && importDesc.Name != 0 {
+		handle, err := windows.LoadLibraryEx(windows.BytePtrToString((*byte)(a2p(module.codeBase+uintptr(importDesc.Name)))), 0, windows.LOAD_LIBRARY_SEARCH_SYSTEM32)
+		if err != nil {
+			return fmt.Errorf("Error loading module: %w", err)
+		}
+		var thunkRef, funcRef *uintptr
+		if importDesc.OriginalFirstThunk() != 0 {
+			thunkRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.OriginalFirstThunk())))
+			funcRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.FirstThunk)))
+		} else {
+			// No hint table.
+			thunkRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.FirstThunk)))
+			funcRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.FirstThunk)))
+		}
+		for *thunkRef != 0 {
+			if IMAGE_SNAP_BY_ORDINAL(*thunkRef) {
+				*funcRef, err = windows.GetProcAddressByOrdinal(handle, IMAGE_ORDINAL(*thunkRef))
+			} else {
+				thunkData := (*IMAGE_IMPORT_BY_NAME)(a2p(module.codeBase + *thunkRef))
+				*funcRef, err = windows.GetProcAddress(handle, windows.BytePtrToString(&thunkData.Name[0]))
+			}
+			if err != nil {
+				windows.FreeLibrary(handle)
+				return fmt.Errorf("Error getting function address: %w", err)
+			}
+			thunkRef = (*uintptr)(a2p(uintptr(unsafe.Pointer(thunkRef)) + unsafe.Sizeof(*thunkRef)))
+			funcRef = (*uintptr)(a2p(uintptr(unsafe.Pointer(funcRef)) + unsafe.Sizeof(*funcRef)))
+		}
+		module.modules = append(module.modules, handle)
+		importDesc = (*IMAGE_IMPORT_DESCRIPTOR)(a2p(uintptr(unsafe.Pointer(importDesc)) + unsafe.Sizeof(*importDesc)))
+	}
+	return nil
+}
+
+func (module *Module) buildNameExports() error {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXPORT)
+	if directory.Size == 0 {
+		return errors.New("No export table found")
+	}
+	exports := (*IMAGE_EXPORT_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	if exports.NumberOfNames == 0 || exports.NumberOfFunctions == 0 {
+		return errors.New("No functions exported")
+	}
+	if exports.NumberOfNames == 0 {
+		return errors.New("No functions exported by name")
+	}
+	var nameRefs []uint32
+	unsafeSlice(unsafe.Pointer(&nameRefs), a2p(module.codeBase+uintptr(exports.AddressOfNames)), int(exports.NumberOfNames))
+	var ordinals []uint16
+	unsafeSlice(unsafe.Pointer(&ordinals), a2p(module.codeBase+uintptr(exports.AddressOfNameOrdinals)), int(exports.NumberOfNames))
+	module.nameExports = make(map[string]uint16)
+	for i := range nameRefs {
+		nameArray := windows.BytePtrToString((*byte)(a2p(module.codeBase + uintptr(nameRefs[i]))))
+		module.nameExports[nameArray] = ordinals[i]
+	}
+	return nil
+}
+
+// LoadLibrary loads module image to memory.
+func LoadLibrary(data []byte) (module *Module, err error) {
+	addr := uintptr(unsafe.Pointer(&data[0]))
+	size := uintptr(len(data))
+	if size < unsafe.Sizeof(IMAGE_DOS_HEADER{}) {
+		return nil, errors.New("Incomplete IMAGE_DOS_HEADER")
+	}
+	dosHeader := (*IMAGE_DOS_HEADER)(a2p(addr))
+	if dosHeader.E_magic != IMAGE_DOS_SIGNATURE {
+		return nil, fmt.Errorf("Not an MS-DOS binary (provided: %x, expected: %x)", dosHeader.E_magic, IMAGE_DOS_SIGNATURE)
+	}
+	if (size < uintptr(dosHeader.E_lfanew)+unsafe.Sizeof(IMAGE_NT_HEADERS{})) {
+		return nil, errors.New("Incomplete IMAGE_NT_HEADERS")
+	}
+	oldHeader := (*IMAGE_NT_HEADERS)(a2p(addr + uintptr(dosHeader.E_lfanew)))
+	if oldHeader.Signature != IMAGE_NT_SIGNATURE {
+		return nil, fmt.Errorf("Not an NT binary (provided: %x, expected: %x)", oldHeader.Signature, IMAGE_NT_SIGNATURE)
+	}
+	if oldHeader.FileHeader.Machine != imageFileProcess {
+		return nil, fmt.Errorf("Foreign platform (provided: %x, expected: %x)", oldHeader.FileHeader.Machine, imageFileProcess)
+	}
+	if (oldHeader.OptionalHeader.SectionAlignment & 1) != 0 {
+		return nil, errors.New("Unaligned section")
+	}
+	lastSectionEnd := uintptr(0)
+	sections := oldHeader.Sections()
+	optionalSectionSize := oldHeader.OptionalHeader.SectionAlignment
+	for i := range sections {
+		var endOfSection uintptr
+		if sections[i].SizeOfRawData == 0 {
+			// Section without data in the DLL
+			endOfSection = uintptr(sections[i].VirtualAddress) + uintptr(optionalSectionSize)
+		} else {
+			endOfSection = uintptr(sections[i].VirtualAddress) + uintptr(sections[i].SizeOfRawData)
+		}
+		if endOfSection > lastSectionEnd {
+			lastSectionEnd = endOfSection
+		}
+	}
+	alignedImageSize := alignUp(uintptr(oldHeader.OptionalHeader.SizeOfImage), uintptr(oldHeader.OptionalHeader.SectionAlignment))
+	if alignedImageSize != alignUp(lastSectionEnd, uintptr(oldHeader.OptionalHeader.SectionAlignment)) {
+		return nil, errors.New("Section is not page-aligned")
+	}
+
+	module = &Module{isDLL: (oldHeader.FileHeader.Characteristics & IMAGE_FILE_DLL) != 0}
+	defer func() {
+		if err != nil {
+			module.Free()
+			module = nil
+		}
+	}()
+
+	// Reserve memory for image of library.
+	// TODO: Is it correct to commit the complete memory region at once? Calling DllEntry raises an exception if we don't.
+	module.codeBase, err = windows.VirtualAlloc(oldHeader.OptionalHeader.ImageBase,
+		alignedImageSize,
+		windows.MEM_RESERVE|windows.MEM_COMMIT,
+		windows.PAGE_READWRITE)
+	if err != nil {
+		// Try to allocate memory at arbitrary position.
+		module.codeBase, err = windows.VirtualAlloc(0,
+			alignedImageSize,
+			windows.MEM_RESERVE|windows.MEM_COMMIT,
+			windows.PAGE_READWRITE)
+		if err != nil {
+			err = fmt.Errorf("Error allocating code: %w", err)
+			return
+		}
+	}
+	err = module.check4GBBoundaries(alignedImageSize)
+	if err != nil {
+		err = fmt.Errorf("Error reallocating code: %w", err)
+		return
+	}
+
+	if size < uintptr(oldHeader.OptionalHeader.SizeOfHeaders) {
+		err = errors.New("Incomplete headers")
+		return
+	}
+	// Commit memory for headers.
+	headers, err := windows.VirtualAlloc(module.codeBase,
+		uintptr(oldHeader.OptionalHeader.SizeOfHeaders),
+		windows.MEM_COMMIT,
+		windows.PAGE_READWRITE)
+	if err != nil {
+		err = fmt.Errorf("Error allocating headers: %w", err)
+		return
+	}
+	// Copy PE header to code.
+	memcpy(headers, addr, uintptr(oldHeader.OptionalHeader.SizeOfHeaders))
+	module.headers = (*IMAGE_NT_HEADERS)(a2p(headers + uintptr(dosHeader.E_lfanew)))
+
+	// Update position.
+	module.headers.OptionalHeader.ImageBase = module.codeBase
+
+	// Copy sections from DLL file block to new memory location.
+	err = module.copySections(addr, size, oldHeader)
+	if err != nil {
+		err = fmt.Errorf("Error copying sections: %w", err)
+		return
+	}
+
+	// Adjust base address of imported data.
+	locationDelta := module.headers.OptionalHeader.ImageBase - oldHeader.OptionalHeader.ImageBase
+	if locationDelta != 0 {
+		module.isRelocated, err = module.performBaseRelocation(locationDelta)
+		if err != nil {
+			err = fmt.Errorf("Error relocating module: %w", err)
+			return
+		}
+	} else {
+		module.isRelocated = true
+	}
+
+	// Load required dlls and adjust function table of imports.
+	err = module.buildImportTable()
+	if err != nil {
+		err = fmt.Errorf("Error building import table: %w", err)
+		return
+	}
+
+	// Mark memory pages depending on section headers and release sections that are marked as "discardable".
+	err = module.finalizeSections()
+	if err != nil {
+		err = fmt.Errorf("Error finalizing sections: %w", err)
+		return
+	}
+
+	// TLS callbacks are executed BEFORE the main loading.
+	module.executeTLS()
+
+	// Get entry point of loaded module.
+	if module.headers.OptionalHeader.AddressOfEntryPoint != 0 {
+		module.entry = module.codeBase + uintptr(module.headers.OptionalHeader.AddressOfEntryPoint)
+		if module.isDLL {
+			// Notify library about attaching to process.
+			r0, _, _ := syscall.Syscall(module.entry, 3, module.codeBase, uintptr(DLL_PROCESS_ATTACH), 0)
+			successful := r0 != 0
+			if !successful {
+				err = windows.ERROR_DLL_INIT_FAILED
+				return
+			}
+			module.initialized = true
+		}
+	}
+
+	module.buildNameExports()
+	return
+}
+
+// Free releases module resources and unloads it.
+func (module *Module) Free() {
+	if module.initialized {
+		// Notify library about detaching from process.
+		syscall.Syscall(module.entry, 3, module.codeBase, uintptr(DLL_PROCESS_DETACH), 0)
+		module.initialized = false
+	}
+	if module.modules != nil {
+		// Free previously opened libraries.
+		for _, handle := range module.modules {
+			windows.FreeLibrary(handle)
+		}
+		module.modules = nil
+	}
+	if module.codeBase != 0 {
+		windows.VirtualFree(module.codeBase, 0, windows.MEM_RELEASE)
+		module.codeBase = 0
+	}
+	if module.blockedMemory != nil {
+		module.blockedMemory.free()
+		module.blockedMemory = nil
+	}
+}
+
+// ProcAddressByName returns function address by exported name.
+func (module *Module) ProcAddressByName(name string) (uintptr, error) {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXPORT)
+	if directory.Size == 0 {
+		return 0, errors.New("No export table found")
+	}
+	exports := (*IMAGE_EXPORT_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	if module.nameExports == nil {
+		return 0, errors.New("No functions exported by name")
+	}
+	if idx, ok := module.nameExports[name]; ok {
+		if uint32(idx) > exports.NumberOfFunctions {
+			return 0, errors.New("Ordinal number too high")
+		}
+		// AddressOfFunctions contains the RVAs to the "real" functions.
+		return module.codeBase + uintptr(*(*uint32)(a2p(module.codeBase + uintptr(exports.AddressOfFunctions) + uintptr(idx)*4))), nil
+	}
+	return 0, errors.New("Function not found by name")
+}
+
+// ProcAddressByOrdinal returns function address by exported ordinal.
+func (module *Module) ProcAddressByOrdinal(ordinal uint16) (uintptr, error) {
+	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXPORT)
+	if directory.Size == 0 {
+		return 0, errors.New("No export table found")
+	}
+	exports := (*IMAGE_EXPORT_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
+	if uint32(ordinal) < exports.Base {
+		return 0, errors.New("Ordinal number too low")
+	}
+	idx := ordinal - uint16(exports.Base)
+	if uint32(idx) > exports.NumberOfFunctions {
+		return 0, errors.New("Ordinal number too high")
+	}
+	// AddressOfFunctions contains the RVAs to the "real" functions.
+	return module.codeBase + uintptr(*(*uint32)(a2p(module.codeBase + uintptr(exports.AddressOfFunctions) + uintptr(idx)*4))), nil
+}
+
+func alignDown(value, alignment uintptr) uintptr {
+	return value & ^(alignment - 1)
+}
+
+func alignUp(value, alignment uintptr) uintptr {
+	return (value + alignment - 1) & ^(alignment - 1)
+}
+
+func a2p(addr uintptr) unsafe.Pointer {
+	return unsafe.Pointer(addr)
+}
+
+func memcpy(dst, src, size uintptr) {
+	var d, s []byte
+	unsafeSlice(unsafe.Pointer(&d), a2p(dst), int(size))
+	unsafeSlice(unsafe.Pointer(&s), a2p(src), int(size))
+	copy(d, s)
+}
+
+// unsafeSlice updates the slice slicePtr to be a slice
+// referencing the provided data with its length & capacity set to
+// lenCap.
+//
+// TODO: when Go 1.16 or Go 1.17 is the minimum supported version,
+// update callers to use unsafe.Slice instead of this.
+func unsafeSlice(slicePtr, data unsafe.Pointer, lenCap int) {
+	type sliceHeader struct {
+		Data unsafe.Pointer
+		Len  int
+		Cap  int
+	}
+	h := (*sliceHeader)(slicePtr)
+	h.Data = data
+	h.Len = lenCap
+	h.Cap = lenCap
+}

tun/wintun/memmod/memmod_windows_32.go

@@ -0,0 +1,16 @@
+// +build windows,386 windows,arm
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package memmod
+
+func (opthdr *IMAGE_OPTIONAL_HEADER) imageOffset() uintptr {
+	return 0
+}
+
+func (module *Module) check4GBBoundaries(alignedImageSize uintptr) (err error) {
+	return
+}

tun/wintun/memmod/memmod_windows_386.go

@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package memmod
+
+const imageFileProcess = IMAGE_FILE_MACHINE_I386

tun/wintun/memmod/memmod_windows_64.go

@@ -0,0 +1,36 @@
+// +build windows,amd64 windows,arm64
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package memmod
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/windows"
+)
+
+func (opthdr *IMAGE_OPTIONAL_HEADER) imageOffset() uintptr {
+	return uintptr(opthdr.ImageBase & 0xffffffff00000000)
+}
+
+func (module *Module) check4GBBoundaries(alignedImageSize uintptr) (err error) {
+	for (module.codeBase >> 32) < ((module.codeBase + alignedImageSize) >> 32) {
+		node := &addressList{
+			next:    module.blockedMemory,
+			address: module.codeBase,
+		}
+		module.blockedMemory = node
+		module.codeBase, err = windows.VirtualAlloc(0,
+			alignedImageSize,
+			windows.MEM_RESERVE|windows.MEM_COMMIT,
+			windows.PAGE_READWRITE)
+		if err != nil {
+			return fmt.Errorf("Error allocating memory block: %w", err)
+		}
+	}
+	return
+}