conn: make binds replacable

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

device/device.go

@@ -279,11 +279,12 @@ func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
 	return nil
 }
 
-func NewDevice(tunDevice tun.Device, logger *Logger) *Device {
+func NewDevice(tunDevice tun.Device, bind conn.Bind, logger *Logger) *Device {
 	device := new(Device)
 	device.state.state = uint32(deviceStateDown)
 	device.closed = make(chan struct{})
 	device.log = logger
+	device.net.bind = bind
 	device.tun.device = tunDevice
 	mtu, err := device.tun.device.MTU()
 	if err != nil {
@@ -302,11 +303,6 @@ func NewDevice(tunDevice tun.Device, logger *Logger) *Device {
 	device.queue.encryption = newOutboundQueue()
 	device.queue.decryption = newInboundQueue()
 
-	// prepare net
-
-	device.net.port = 0
-	device.net.bind = nil
-
 	// start workers
 
 	cpus := runtime.NumCPU()
@@ -414,7 +410,6 @@ func unsafeCloseBind(device *Device) error {
 	}
 	if netc.bind != nil {
 		err = netc.bind.Close()
-		netc.bind = nil
 	}
 	netc.stopping.Wait()
 	return err
@@ -474,16 +469,14 @@ func (device *Device) BindUpdate() error {
 	// bind to new port
 	var err error
 	netc := &device.net
-	netc.bind, netc.port, err = conn.CreateBind(netc.port)
+	netc.port, err = netc.bind.Open(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
 	}

device/device_test.go

@@ -21,6 +21,7 @@ import (
 	"testing"
 	"time"
 
+	"golang.zx2c4.com/wireguard/conn"
 	"golang.zx2c4.com/wireguard/tun/tuntest"
 )
 
@@ -158,7 +159,7 @@ func genTestPair(tb testing.TB) (pair testPair) {
 		if _, ok := tb.(*testing.B); ok && !testing.Verbose() {
 			level = LogLevelError
 		}
-		p.dev = NewDevice(p.tun.TUN(), NewLogger(level, fmt.Sprintf("dev%d: ", i)))
+		p.dev = NewDevice(p.tun.TUN(), conn.NewDefaultBind(), 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()
@@ -332,7 +333,7 @@ func randDevice(t *testing.T) *Device {
 	}
 	tun := newDummyTUN("dummy")
 	logger := NewLogger(LogLevelError, "")
-	device := NewDevice(tun, logger)
+	device := NewDevice(tun, conn.NewDefaultBind(), logger)
 	device.SetPrivateKey(sk)
 	return device
 }

device/peer.go

@@ -126,13 +126,8 @@ func (peer *Peer) SendBuffer(buffer []byte) error {
 	peer.device.net.RLock()
 	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")
+	if peer.device.isClosed() {
+		return nil
 	}
 
 	peer.RLock()

device/sticky_default.go

@@ -1,4 +1,4 @@
-// +build !linux android
+// +build !linux
 
 package device
 

device/sticky_linux.go

@@ -1,5 +1,3 @@
-// +build !android
-
 /* SPDX-License-Identifier: MIT
  *
  * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
@@ -21,11 +19,16 @@ import (
 	"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) {
+	if _, ok := bind.(*conn.LinuxSocketBind); !ok {
+		return nil, nil
+	}
+
 	netlinkSock, err := createNetlinkRouteSocket()
 	if err != nil {
 		return nil, err
@@ -109,11 +112,11 @@ func (device *Device) routineRouteListener(bind conn.Bind, netlinkSock int, netl
 									pePtr.peer.Unlock()
 									break
 								}
-								if uint32(pePtr.peer.endpoint.(*conn.NativeEndpoint).Src4().Ifindex) == ifidx {
+								if uint32(pePtr.peer.endpoint.(*conn.LinuxSocketEndpoint).Src4().Ifindex) == ifidx {
 									pePtr.peer.Unlock()
 									break
 								}
-								pePtr.peer.endpoint.(*conn.NativeEndpoint).ClearSrc()
+								pePtr.peer.endpoint.(*conn.LinuxSocketEndpoint).ClearSrc()
 								pePtr.peer.Unlock()
 							}
 							attr = attr[attrhdr.Len:]
@@ -133,7 +136,7 @@ func (device *Device) routineRouteListener(bind conn.Bind, netlinkSock int, netl
 							peer.RUnlock()
 							continue
 						}
-						nativeEP, _ := peer.endpoint.(*conn.NativeEndpoint)
+						nativeEP, _ := peer.endpoint.(*conn.LinuxSocketEndpoint)
 						if nativeEP == nil {
 							peer.RUnlock()
 							continue
@@ -176,7 +179,7 @@ func (device *Device) routineRouteListener(bind conn.Bind, netlinkSock int, netl
 								Len:  8,
 								Type: unix.RTA_MARK,
 							},
-							uint32(bind.LastMark()),
+							device.net.fwmark,
 						}
 						nlmsg.hdr.Len = uint32(unsafe.Sizeof(nlmsg))
 						reqPeerLock.Lock()

device/uapi.go

@@ -18,7 +18,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	"golang.zx2c4.com/wireguard/conn"
 	"golang.zx2c4.com/wireguard/ipc"
 )
 
@@ -331,7 +330,7 @@ func (device *Device) handlePeerLine(peer *ipcSetPeer, key, value string) error
 
 	case "endpoint":
 		device.log.Verbosef("%v - UAPI: Updating endpoint", peer.Peer)
-		endpoint, err := conn.CreateEndpoint(value)
+		endpoint, err := device.net.bind.ParseEndpoint(value)
 		if err != nil {
 			return ipcErrorf(ipc.IpcErrorInvalid, "failed to set endpoint %v: %w", value, err)
 		}