conn: implement RIO for fast Windows UDP sockets
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld
581
conn/bind_windows.go
Normal file
581
conn/bind_windows.go
Normal file
@@ -0,0 +1,581 @@
|
||||
/* SPDX-License-Identifier: MIT
|
||||
*
|
||||
* Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
|
||||
*/
|
||||
|
||||
package conn
|
||||
|
||||
import (
|
||||
"encoding/binary"
|
||||
"io"
|
||||
"net"
|
||||
"strconv"
|
||||
"sync"
|
||||
"sync/atomic"
|
||||
"unsafe"
|
||||
|
||||
"golang.org/x/sys/windows"
|
||||
|
||||
"golang.zx2c4.com/wireguard/conn/winrio"
|
||||
)
|
||||
|
||||
const (
|
||||
packetsPerRing = 1024
|
||||
bytesPerPacket = 2048 - 32
|
||||
receiveSpins = 15
|
||||
)
|
||||
|
||||
type ringPacket struct {
|
||||
addr WinRingEndpoint
|
||||
data [bytesPerPacket]byte
|
||||
}
|
||||
|
||||
type ringBuffer struct {
|
||||
packets uintptr
|
||||
head, tail uint32
|
||||
id winrio.BufferId
|
||||
iocp windows.Handle
|
||||
isFull bool
|
||||
cq winrio.Cq
|
||||
mu sync.Mutex
|
||||
overlapped windows.Overlapped
|
||||
}
|
||||
|
||||
func (rb *ringBuffer) Push() *ringPacket {
|
||||
for rb.isFull {
|
||||
panic("ring is full")
|
||||
}
|
||||
ret := (*ringPacket)(unsafe.Pointer(rb.packets + (uintptr(rb.tail%packetsPerRing) * unsafe.Sizeof(ringPacket{}))))
|
||||
rb.tail += 1
|
||||
if rb.tail == rb.head {
|
||||
rb.isFull = true
|
||||
}
|
||||
return ret
|
||||
}
|
||||
|
||||
func (rb *ringBuffer) Return(count uint32) {
|
||||
if rb.head%packetsPerRing == rb.tail%packetsPerRing && !rb.isFull {
|
||||
return
|
||||
}
|
||||
rb.head += count
|
||||
rb.isFull = false
|
||||
}
|
||||
|
||||
type afWinRingBind struct {
|
||||
sock windows.Handle
|
||||
rx, tx ringBuffer
|
||||
rq winrio.Rq
|
||||
mu sync.Mutex
|
||||
blackhole bool
|
||||
}
|
||||
|
||||
// WinRingBind uses Windows registered I/O for fast ring buffered networking.
|
||||
type WinRingBind struct {
|
||||
v4, v6 afWinRingBind
|
||||
mu sync.RWMutex
|
||||
isOpen uint32
|
||||
}
|
||||
|
||||
func NewDefaultBind() Bind { return NewWinRingBind() }
|
||||
|
||||
func NewWinRingBind() Bind {
|
||||
if !winrio.Initialize() {
|
||||
return NewStdNetBind()
|
||||
}
|
||||
return new(WinRingBind)
|
||||
}
|
||||
|
||||
type WinRingEndpoint struct {
|
||||
family uint16
|
||||
data [30]byte
|
||||
}
|
||||
|
||||
var _ Bind = (*WinRingBind)(nil)
|
||||
var _ Endpoint = (*WinRingEndpoint)(nil)
|
||||
|
||||
func (*WinRingBind) ParseEndpoint(s string) (Endpoint, error) {
|
||||
host, port, err := net.SplitHostPort(s)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
host16, err := windows.UTF16PtrFromString(host)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
port16, err := windows.UTF16PtrFromString(port)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
hints := windows.AddrinfoW{
|
||||
Flags: windows.AI_NUMERICHOST,
|
||||
Family: windows.AF_UNSPEC,
|
||||
Socktype: windows.SOCK_DGRAM,
|
||||
Protocol: windows.IPPROTO_UDP,
|
||||
}
|
||||
var addrinfo *windows.AddrinfoW
|
||||
err = windows.GetAddrInfoW(host16, port16, &hints, &addrinfo)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
defer windows.FreeAddrInfoW(addrinfo)
|
||||
if (addrinfo.Family != windows.AF_INET && addrinfo.Family != windows.AF_INET6) || addrinfo.Addrlen > unsafe.Sizeof(WinRingEndpoint{}) {
|
||||
return nil, windows.ERROR_INVALID_ADDRESS
|
||||
}
|
||||
var src []byte
|
||||
var dst [unsafe.Sizeof(WinRingEndpoint{})]byte
|
||||
unsafeSlice(unsafe.Pointer(&src), unsafe.Pointer(addrinfo.Addr), int(addrinfo.Addrlen))
|
||||
copy(dst[:], src)
|
||||
return (*WinRingEndpoint)(unsafe.Pointer(&dst[0])), nil
|
||||
}
|
||||
|
||||
func (*WinRingEndpoint) ClearSrc() {}
|
||||
|
||||
func (e *WinRingEndpoint) DstIP() net.IP {
|
||||
switch e.family {
|
||||
case windows.AF_INET:
|
||||
return append([]byte{}, e.data[2:6]...)
|
||||
case windows.AF_INET6:
|
||||
return append([]byte{}, e.data[6:22]...)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func (e *WinRingEndpoint) SrcIP() net.IP {
|
||||
return nil // not supported
|
||||
}
|
||||
|
||||
func (e *WinRingEndpoint) DstToBytes() []byte {
|
||||
switch e.family {
|
||||
case windows.AF_INET:
|
||||
b := make([]byte, 0, 6)
|
||||
b = append(b, e.data[2:6]...)
|
||||
b = append(b, e.data[1], e.data[0])
|
||||
return b
|
||||
case windows.AF_INET6:
|
||||
b := make([]byte, 0, 18)
|
||||
b = append(b, e.data[6:22]...)
|
||||
b = append(b, e.data[1], e.data[0])
|
||||
return b
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func (e *WinRingEndpoint) DstToString() string {
|
||||
switch e.family {
|
||||
case windows.AF_INET:
|
||||
addr := net.UDPAddr{IP: e.data[2:6], Port: int(binary.BigEndian.Uint16(e.data[0:2]))}
|
||||
return addr.String()
|
||||
case windows.AF_INET6:
|
||||
var zone string
|
||||
if scope := *(*uint32)(unsafe.Pointer(&e.data[22])); scope > 0 {
|
||||
zone = strconv.FormatUint(uint64(scope), 10)
|
||||
}
|
||||
addr := net.UDPAddr{IP: e.data[6:22], Zone: zone, Port: int(binary.BigEndian.Uint16(e.data[0:2]))}
|
||||
return addr.String()
|
||||
}
|
||||
return ""
|
||||
}
|
||||
|
||||
func (e *WinRingEndpoint) SrcToString() string {
|
||||
return ""
|
||||
}
|
||||
|
||||
func (ring *ringBuffer) CloseAndZero() {
|
||||
if ring.cq != 0 {
|
||||
winrio.CloseCompletionQueue(ring.cq)
|
||||
ring.cq = 0
|
||||
}
|
||||
if ring.iocp != 0 {
|
||||
windows.CloseHandle(ring.iocp)
|
||||
ring.iocp = 0
|
||||
}
|
||||
if ring.id != 0 {
|
||||
winrio.DeregisterBuffer(ring.id)
|
||||
ring.id = 0
|
||||
}
|
||||
if ring.packets != 0 {
|
||||
windows.VirtualFree(ring.packets, 0, windows.MEM_RELEASE)
|
||||
ring.packets = 0
|
||||
}
|
||||
}
|
||||
|
||||
func (bind *afWinRingBind) CloseAndZero() {
|
||||
bind.rx.CloseAndZero()
|
||||
bind.tx.CloseAndZero()
|
||||
if bind.sock != 0 {
|
||||
windows.CloseHandle(bind.sock)
|
||||
bind.sock = 0
|
||||
}
|
||||
bind.blackhole = false
|
||||
}
|
||||
|
||||
func (bind *WinRingBind) closeAndZero() {
|
||||
atomic.StoreUint32(&bind.isOpen, 0)
|
||||
bind.v4.CloseAndZero()
|
||||
bind.v6.CloseAndZero()
|
||||
}
|
||||
|
||||
func (ring *ringBuffer) Open() error {
|
||||
var err error
|
||||
packetsLen := unsafe.Sizeof(ringPacket{}) * packetsPerRing
|
||||
ring.packets, err = windows.VirtualAlloc(0, packetsLen, windows.MEM_COMMIT|windows.MEM_RESERVE, windows.PAGE_READWRITE)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
ring.id, err = winrio.RegisterPointer(unsafe.Pointer(ring.packets), uint32(packetsLen))
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
ring.iocp, err = windows.CreateIoCompletionPort(windows.InvalidHandle, 0, 0, 0)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
ring.cq, err = winrio.CreateIOCPCompletionQueue(packetsPerRing, ring.iocp, 0, &ring.overlapped)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func (bind *afWinRingBind) Open(family int32, sa windows.Sockaddr) (windows.Sockaddr, error) {
|
||||
var err error
|
||||
bind.sock, err = winrio.Socket(family, windows.SOCK_DGRAM, windows.IPPROTO_UDP)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
err = bind.rx.Open()
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
err = bind.tx.Open()
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
bind.rq, err = winrio.CreateRequestQueue(bind.sock, packetsPerRing, 1, packetsPerRing, 1, bind.rx.cq, bind.tx.cq, 0)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
err = windows.Bind(bind.sock, sa)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
sa, err = windows.Getsockname(bind.sock)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return sa, nil
|
||||
}
|
||||
|
||||
func (bind *WinRingBind) Open(port uint16) (selectedPort uint16, err error) {
|
||||
bind.mu.Lock()
|
||||
defer bind.mu.Unlock()
|
||||
defer func() {
|
||||
if err != nil {
|
||||
bind.closeAndZero()
|
||||
}
|
||||
}()
|
||||
if atomic.LoadUint32(&bind.isOpen) != 0 {
|
||||
return 0, ErrBindAlreadyOpen
|
||||
}
|
||||
var sa windows.Sockaddr
|
||||
sa, err = bind.v4.Open(windows.AF_INET, &windows.SockaddrInet4{Port: int(port)})
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
sa, err = bind.v6.Open(windows.AF_INET6, &windows.SockaddrInet6{Port: sa.(*windows.SockaddrInet4).Port})
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
selectedPort = uint16(sa.(*windows.SockaddrInet6).Port)
|
||||
for i := 0; i < packetsPerRing; i++ {
|
||||
err = bind.v4.InsertReceiveRequest()
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
err = bind.v6.InsertReceiveRequest()
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
}
|
||||
atomic.StoreUint32(&bind.isOpen, 1)
|
||||
return
|
||||
}
|
||||
|
||||
func (bind *WinRingBind) Close() error {
|
||||
bind.mu.RLock()
|
||||
if atomic.LoadUint32(&bind.isOpen) != 1 {
|
||||
bind.mu.RUnlock()
|
||||
return nil
|
||||
}
|
||||
atomic.StoreUint32(&bind.isOpen, 2)
|
||||
windows.PostQueuedCompletionStatus(bind.v4.rx.iocp, 0, 0, nil)
|
||||
windows.PostQueuedCompletionStatus(bind.v4.tx.iocp, 0, 0, nil)
|
||||
windows.PostQueuedCompletionStatus(bind.v6.rx.iocp, 0, 0, nil)
|
||||
windows.PostQueuedCompletionStatus(bind.v6.tx.iocp, 0, 0, nil)
|
||||
bind.mu.RUnlock()
|
||||
bind.mu.Lock()
|
||||
defer bind.mu.Unlock()
|
||||
bind.closeAndZero()
|
||||
return nil
|
||||
}
|
||||
|
||||
func (bind *WinRingBind) SetMark(mark uint32) error {
|
||||
return nil
|
||||
}
|
||||
|
||||
func (bind *afWinRingBind) InsertReceiveRequest() error {
|
||||
packet := bind.rx.Push()
|
||||
dataBuffer := &winrio.Buffer{
|
||||
Id: bind.rx.id,
|
||||
Offset: uint32(uintptr(unsafe.Pointer(&packet.data[0])) - bind.rx.packets),
|
||||
Length: uint32(len(packet.data)),
|
||||
}
|
||||
addressBuffer := &winrio.Buffer{
|
||||
Id: bind.rx.id,
|
||||
Offset: uint32(uintptr(unsafe.Pointer(&packet.addr)) - bind.rx.packets),
|
||||
Length: uint32(unsafe.Sizeof(packet.addr)),
|
||||
}
|
||||
bind.mu.Lock()
|
||||
defer bind.mu.Unlock()
|
||||
return winrio.ReceiveEx(bind.rq, dataBuffer, 1, nil, addressBuffer, nil, nil, 0, uintptr(unsafe.Pointer(packet)))
|
||||
}
|
||||
|
||||
//go:linkname procyield runtime.procyield
|
||||
func procyield(cycles uint32)
|
||||
|
||||
func (bind *afWinRingBind) Receive(buf []byte, isOpen *uint32) (int, Endpoint, error) {
|
||||
if atomic.LoadUint32(isOpen) != 1 {
|
||||
return 0, nil, net.ErrClosed
|
||||
}
|
||||
bind.rx.mu.Lock()
|
||||
defer bind.rx.mu.Unlock()
|
||||
var count uint32
|
||||
var results [1]winrio.Result
|
||||
for tries := 0; count == 0 && tries < receiveSpins; tries++ {
|
||||
if tries > 0 {
|
||||
if atomic.LoadUint32(isOpen) != 1 {
|
||||
return 0, nil, net.ErrClosed
|
||||
}
|
||||
procyield(1)
|
||||
}
|
||||
count = winrio.DequeueCompletion(bind.rx.cq, results[:])
|
||||
}
|
||||
if count == 0 {
|
||||
err := winrio.Notify(bind.rx.cq)
|
||||
if err != nil {
|
||||
return 0, nil, err
|
||||
}
|
||||
var bytes uint32
|
||||
var key uintptr
|
||||
var overlapped *windows.Overlapped
|
||||
err = windows.GetQueuedCompletionStatus(bind.rx.iocp, &bytes, &key, &overlapped, windows.INFINITE)
|
||||
if err != nil {
|
||||
return 0, nil, err
|
||||
}
|
||||
if atomic.LoadUint32(isOpen) != 1 {
|
||||
return 0, nil, net.ErrClosed
|
||||
}
|
||||
count = winrio.DequeueCompletion(bind.rx.cq, results[:])
|
||||
if count == 0 {
|
||||
return 0, nil, io.ErrNoProgress
|
||||
|
||||
}
|
||||
}
|
||||
bind.rx.Return(1)
|
||||
err := bind.InsertReceiveRequest()
|
||||
if err != nil {
|
||||
return 0, nil, err
|
||||
}
|
||||
if results[0].Status != 0 {
|
||||
return 0, nil, windows.Errno(results[0].Status)
|
||||
}
|
||||
packet := (*ringPacket)(unsafe.Pointer(uintptr(results[0].RequestContext)))
|
||||
ep := packet.addr
|
||||
n := copy(buf, packet.data[:results[0].BytesTransferred])
|
||||
return n, &ep, nil
|
||||
}
|
||||
|
||||
func (bind *WinRingBind) ReceiveIPv4(buf []byte) (int, Endpoint, error) {
|
||||
bind.mu.RLock()
|
||||
defer bind.mu.RUnlock()
|
||||
return bind.v4.Receive(buf, &bind.isOpen)
|
||||
}
|
||||
|
||||
func (bind *WinRingBind) ReceiveIPv6(buf []byte) (int, Endpoint, error) {
|
||||
bind.mu.RLock()
|
||||
defer bind.mu.RUnlock()
|
||||
return bind.v6.Receive(buf, &bind.isOpen)
|
||||
}
|
||||
|
||||
func (bind *afWinRingBind) Send(buf []byte, nend *WinRingEndpoint, isOpen *uint32) error {
|
||||
if atomic.LoadUint32(isOpen) != 1 {
|
||||
return net.ErrClosed
|
||||
}
|
||||
if len(buf) > bytesPerPacket {
|
||||
return io.ErrShortBuffer
|
||||
}
|
||||
bind.tx.mu.Lock()
|
||||
defer bind.tx.mu.Unlock()
|
||||
var results [packetsPerRing]winrio.Result
|
||||
count := winrio.DequeueCompletion(bind.tx.cq, results[:])
|
||||
if count == 0 && bind.tx.isFull {
|
||||
err := winrio.Notify(bind.tx.cq)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
var bytes uint32
|
||||
var key uintptr
|
||||
var overlapped *windows.Overlapped
|
||||
err = windows.GetQueuedCompletionStatus(bind.tx.iocp, &bytes, &key, &overlapped, windows.INFINITE)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
if atomic.LoadUint32(isOpen) != 1 {
|
||||
return net.ErrClosed
|
||||
}
|
||||
count = winrio.DequeueCompletion(bind.tx.cq, results[:])
|
||||
if count == 0 {
|
||||
return io.ErrNoProgress
|
||||
}
|
||||
}
|
||||
if count > 0 {
|
||||
bind.tx.Return(count)
|
||||
}
|
||||
packet := bind.tx.Push()
|
||||
packet.addr = *nend
|
||||
copy(packet.data[:], buf)
|
||||
dataBuffer := &winrio.Buffer{
|
||||
Id: bind.tx.id,
|
||||
Offset: uint32(uintptr(unsafe.Pointer(&packet.data[0])) - bind.tx.packets),
|
||||
Length: uint32(len(buf)),
|
||||
}
|
||||
addressBuffer := &winrio.Buffer{
|
||||
Id: bind.tx.id,
|
||||
Offset: uint32(uintptr(unsafe.Pointer(&packet.addr)) - bind.tx.packets),
|
||||
Length: uint32(unsafe.Sizeof(packet.addr)),
|
||||
}
|
||||
bind.mu.Lock()
|
||||
defer bind.mu.Unlock()
|
||||
return winrio.SendEx(bind.rq, dataBuffer, 1, nil, addressBuffer, nil, nil, 0, 0)
|
||||
}
|
||||
|
||||
func (bind *WinRingBind) Send(buf []byte, endpoint Endpoint) error {
|
||||
nend, ok := endpoint.(*WinRingEndpoint)
|
||||
if !ok {
|
||||
return ErrWrongEndpointType
|
||||
}
|
||||
bind.mu.RLock()
|
||||
defer bind.mu.RUnlock()
|
||||
switch nend.family {
|
||||
case windows.AF_INET:
|
||||
if bind.v4.blackhole {
|
||||
return nil
|
||||
}
|
||||
return bind.v4.Send(buf, nend, &bind.isOpen)
|
||||
case windows.AF_INET6:
|
||||
if bind.v6.blackhole {
|
||||
return nil
|
||||
}
|
||||
return bind.v6.Send(buf, nend, &bind.isOpen)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func (bind *StdNetBind) BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error {
|
||||
sysconn, err := bind.ipv4.SyscallConn()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
err2 := sysconn.Control(func(fd uintptr) {
|
||||
err = bindSocketToInterface4(windows.Handle(fd), interfaceIndex)
|
||||
})
|
||||
if err2 != nil {
|
||||
return err2
|
||||
}
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
bind.blackhole4 = blackhole
|
||||
return nil
|
||||
}
|
||||
|
||||
func (bind *StdNetBind) BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error {
|
||||
sysconn, err := bind.ipv6.SyscallConn()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
err2 := sysconn.Control(func(fd uintptr) {
|
||||
err = bindSocketToInterface6(windows.Handle(fd), interfaceIndex)
|
||||
})
|
||||
if err2 != nil {
|
||||
return err2
|
||||
}
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
bind.blackhole6 = blackhole
|
||||
return nil
|
||||
}
|
||||
func (bind *WinRingBind) BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error {
|
||||
bind.mu.RLock()
|
||||
defer bind.mu.RUnlock()
|
||||
if atomic.LoadUint32(&bind.isOpen) != 1 {
|
||||
return net.ErrClosed
|
||||
}
|
||||
err := bindSocketToInterface4(bind.v4.sock, interfaceIndex)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
bind.v4.blackhole = blackhole
|
||||
return nil
|
||||
}
|
||||
|
||||
func (bind *WinRingBind) BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error {
|
||||
bind.mu.RLock()
|
||||
defer bind.mu.RUnlock()
|
||||
if atomic.LoadUint32(&bind.isOpen) != 1 {
|
||||
return net.ErrClosed
|
||||
}
|
||||
err := bindSocketToInterface6(bind.v6.sock, interfaceIndex)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
bind.v6.blackhole = blackhole
|
||||
return nil
|
||||
}
|
||||
|
||||
func bindSocketToInterface4(handle windows.Handle, interfaceIndex uint32) error {
|
||||
const IP_UNICAST_IF = 31
|
||||
/* MSDN says for IPv4 this needs to be in net byte order, so that it's like an IP address with leading zeros. */
|
||||
var bytes [4]byte
|
||||
binary.BigEndian.PutUint32(bytes[:], interfaceIndex)
|
||||
interfaceIndex = *(*uint32)(unsafe.Pointer(&bytes[0]))
|
||||
err := windows.SetsockoptInt(handle, windows.IPPROTO_IP, IP_UNICAST_IF, int(interfaceIndex))
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func bindSocketToInterface6(handle windows.Handle, interfaceIndex uint32) error {
|
||||
const IPV6_UNICAST_IF = 31
|
||||
return windows.SetsockoptInt(handle, windows.IPPROTO_IPV6, IPV6_UNICAST_IF, int(interfaceIndex))
|
||||
}
|
||||
|
||||
// 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
|
||||
}
|
||||
Reference in New Issue
Block a user