// 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 }