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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package net
import (
"context"
"internal/poll"
"internal/syscall/windows"
"os"
"runtime"
"syscall"
"unsafe"
)
const (
readSyscallName = "wsarecv"
readFromSyscallName = "wsarecvfrom"
readMsgSyscallName = "wsarecvmsg"
writeSyscallName = "wsasend"
writeToSyscallName = "wsasendto"
writeMsgSyscallName = "wsasendmsg"
)
// canUseConnectEx reports whether we can use the ConnectEx Windows API call
// for the given network type.
func canUseConnectEx(net string) bool {
switch net {
case "tcp", "tcp4", "tcp6":
return true
}
// ConnectEx windows API does not support connectionless sockets.
return false
}
func newFD(sysfd syscall.Handle, family, sotype int, net string) (*netFD, error) {
ret := &netFD{
pfd: poll.FD{
Sysfd: sysfd,
IsStream: sotype == syscall.SOCK_STREAM,
ZeroReadIsEOF: sotype != syscall.SOCK_DGRAM && sotype != syscall.SOCK_RAW,
},
family: family,
sotype: sotype,
net: net,
}
return ret, nil
}
func (fd *netFD) init() error {
errcall, err := fd.pfd.Init(fd.net, true)
if errcall != "" {
err = wrapSyscallError(errcall, err)
}
return err
}
// Always returns nil for connected peer address result.
func (fd *netFD) connect(ctx context.Context, la, ra syscall.Sockaddr) (syscall.Sockaddr, error) {
// Do not need to call fd.writeLock here,
// because fd is not yet accessible to user,
// so no concurrent operations are possible.
if err := fd.init(); err != nil {
return nil, err
}
if ctx.Done() != nil {
// Propagate the Context's deadline and cancellation.
// If the context is already done, or if it has a nonzero deadline,
// ensure that that is applied before the call to ConnectEx begins
// so that we don't return spurious connections.
defer fd.pfd.SetWriteDeadline(noDeadline)
if ctx.Err() != nil {
fd.pfd.SetWriteDeadline(aLongTimeAgo)
} else {
if deadline, ok := ctx.Deadline(); ok && !deadline.IsZero() {
fd.pfd.SetWriteDeadline(deadline)
}
done := make(chan struct{})
stop := context.AfterFunc(ctx, func() {
// Force the runtime's poller to immediately give
// up waiting for writability.
fd.pfd.SetWriteDeadline(aLongTimeAgo)
close(done)
})
defer func() {
if !stop() {
// Wait for the call to SetWriteDeadline to complete so that we can
// reset the deadline if everything else succeeded.
<-done
}
}()
}
}
if !canUseConnectEx(fd.net) {
err := connectFunc(fd.pfd.Sysfd, ra)
return nil, os.NewSyscallError("connect", err)
}
// ConnectEx windows API requires an unconnected, previously bound socket.
if la == nil {
switch ra.(type) {
case *syscall.SockaddrInet4:
la = &syscall.SockaddrInet4{}
case *syscall.SockaddrInet6:
la = &syscall.SockaddrInet6{}
default:
panic("unexpected type in connect")
}
if err := syscall.Bind(fd.pfd.Sysfd, la); err != nil {
return nil, os.NewSyscallError("bind", err)
}
}
var isloopback bool
switch ra := ra.(type) {
case *syscall.SockaddrInet4:
isloopback = ra.Addr[0] == 127
case *syscall.SockaddrInet6:
isloopback = ra.Addr == [16]byte(IPv6loopback)
default:
panic("unexpected type in connect")
}
if isloopback {
// This makes ConnectEx() fails faster if the target port on the localhost
// is not reachable, instead of waiting for 2s.
params := windows.TCP_INITIAL_RTO_PARAMETERS{
Rtt: windows.TCP_INITIAL_RTO_UNSPECIFIED_RTT, // use the default or overridden by the Administrator
MaxSynRetransmissions: 1, // minimum possible value before Windows 10.0.16299
}
if windows.Support_TCP_INITIAL_RTO_NO_SYN_RETRANSMISSIONS() {
// In Windows 10.0.16299 TCP_INITIAL_RTO_NO_SYN_RETRANSMISSIONS makes ConnectEx() fails instantly.
params.MaxSynRetransmissions = windows.TCP_INITIAL_RTO_NO_SYN_RETRANSMISSIONS
}
var out uint32
// Don't abort the connection if WSAIoctl fails, as it is only an optimization.
// If it fails reliably, we expect TestDialClosedPortFailFast to detect it.
_ = fd.pfd.WSAIoctl(windows.SIO_TCP_INITIAL_RTO, (*byte)(unsafe.Pointer(¶ms)), uint32(unsafe.Sizeof(params)), nil, 0, &out, nil, 0)
}
// Call ConnectEx API.
if err := fd.pfd.ConnectEx(ra); err != nil {
select {
case <-ctx.Done():
return nil, mapErr(ctx.Err())
default:
if _, ok := err.(syscall.Errno); ok {
err = os.NewSyscallError("connectex", err)
}
return nil, err
}
}
// Refresh socket properties.
return nil, os.NewSyscallError("setsockopt", syscall.Setsockopt(fd.pfd.Sysfd, syscall.SOL_SOCKET, syscall.SO_UPDATE_CONNECT_CONTEXT, (*byte)(unsafe.Pointer(&fd.pfd.Sysfd)), int32(unsafe.Sizeof(fd.pfd.Sysfd))))
}
func (c *conn) writeBuffers(v *Buffers) (int64, error) {
if !c.ok() {
return 0, syscall.EINVAL
}
n, err := c.fd.writeBuffers(v)
if err != nil {
return n, &OpError{Op: "wsasend", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
}
return n, nil
}
func (fd *netFD) writeBuffers(buf *Buffers) (int64, error) {
n, err := fd.pfd.Writev((*[][]byte)(buf))
runtime.KeepAlive(fd)
return n, wrapSyscallError("wsasend", err)
}
func (fd *netFD) accept() (*netFD, error) {
s, rawsa, rsan, errcall, err := fd.pfd.Accept(func() (syscall.Handle, error) {
return sysSocket(fd.family, fd.sotype, 0)
})
if err != nil {
if errcall != "" {
err = wrapSyscallError(errcall, err)
}
return nil, err
}
// Associate our new socket with IOCP.
netfd, err := newFD(s, fd.family, fd.sotype, fd.net)
if err != nil {
poll.CloseFunc(s)
return nil, err
}
if err := netfd.init(); err != nil {
fd.Close()
return nil, err
}
// Get local and peer addr out of AcceptEx buffer.
var lrsa, rrsa *syscall.RawSockaddrAny
var llen, rlen int32
syscall.GetAcceptExSockaddrs((*byte)(unsafe.Pointer(&rawsa[0])),
0, rsan, rsan, &lrsa, &llen, &rrsa, &rlen)
lsa, _ := lrsa.Sockaddr()
rsa, _ := rrsa.Sockaddr()
netfd.setAddr(netfd.addrFunc()(lsa), netfd.addrFunc()(rsa))
return netfd, nil
}
// Unimplemented functions.
func (fd *netFD) dup() (*os.File, error) {
// TODO: Implement this
return nil, syscall.EWINDOWS
}
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