1 files changed, 299 insertions, 0 deletions
diff --git a/src/net/tcpsock_posix.go b/src/net/tcpsock_posix.go
new file mode 100644
index 000000000..dd78aefa7
--- /dev/null
+++ b/src/net/tcpsock_posix.go
@@ -0,0 +1,299 @@
+// Copyright 2009 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.
+
+// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris windows
+
+package net
+
+import (
+	"io"
+	"os"
+	"syscall"
+	"time"
+)
+
+// BUG(rsc): On OpenBSD, listening on the "tcp" network does not listen for
+// both IPv4 and IPv6 connections. This is due to the fact that IPv4 traffic
+// will not be routed to an IPv6 socket - two separate sockets are required
+// if both AFs are to be supported. See inet6(4) on OpenBSD for details.
+
+func sockaddrToTCP(sa syscall.Sockaddr) Addr {
+	switch sa := sa.(type) {
+	case *syscall.SockaddrInet4:
+		return &TCPAddr{IP: sa.Addr[0:], Port: sa.Port}
+	case *syscall.SockaddrInet6:
+		return &TCPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
+	}
+	return nil
+}
+
+func (a *TCPAddr) family() int {
+	if a == nil || len(a.IP) <= IPv4len {
+		return syscall.AF_INET
+	}
+	if a.IP.To4() != nil {
+		return syscall.AF_INET
+	}
+	return syscall.AF_INET6
+}
+
+func (a *TCPAddr) isWildcard() bool {
+	if a == nil || a.IP == nil {
+		return true
+	}
+	return a.IP.IsUnspecified()
+}
+
+func (a *TCPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
+	if a == nil {
+		return nil, nil
+	}
+	return ipToSockaddr(family, a.IP, a.Port, a.Zone)
+}
+
+// TCPConn is an implementation of the Conn interface for TCP network
+// connections.
+type TCPConn struct {
+	conn
+}
+
+func newTCPConn(fd *netFD) *TCPConn {
+	c := &TCPConn{conn{fd}}
+	c.SetNoDelay(true)
+	return c
+}
+
+// ReadFrom implements the io.ReaderFrom ReadFrom method.
+func (c *TCPConn) ReadFrom(r io.Reader) (int64, error) {
+	if n, err, handled := sendFile(c.fd, r); handled {
+		return n, err
+	}
+	return genericReadFrom(c, r)
+}
+
+// CloseRead shuts down the reading side of the TCP connection.
+// Most callers should just use Close.
+func (c *TCPConn) CloseRead() error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return c.fd.closeRead()
+}
+
+// CloseWrite shuts down the writing side of the TCP connection.
+// Most callers should just use Close.
+func (c *TCPConn) CloseWrite() error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return c.fd.closeWrite()
+}
+
+// SetLinger sets the behavior of Close on a connection which still
+// has data waiting to be sent or to be acknowledged.
+//
+// If sec < 0 (the default), the operating system finishes sending the
+// data in the background.
+//
+// If sec == 0, the operating system discards any unsent or
+// unacknowledged data.
+//
+// If sec > 0, the data is sent in the background as with sec < 0. On
+// some operating systems after sec seconds have elapsed any remaining
+// unsent data may be discarded.
+func (c *TCPConn) SetLinger(sec int) error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return setLinger(c.fd, sec)
+}
+
+// SetKeepAlive sets whether the operating system should send
+// keepalive messages on the connection.
+func (c *TCPConn) SetKeepAlive(keepalive bool) error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return setKeepAlive(c.fd, keepalive)
+}
+
+// SetKeepAlivePeriod sets period between keep alives.
+func (c *TCPConn) SetKeepAlivePeriod(d time.Duration) error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return setKeepAlivePeriod(c.fd, d)
+}
+
+// SetNoDelay controls whether the operating system should delay
+// packet transmission in hopes of sending fewer packets (Nagle's
+// algorithm).  The default is true (no delay), meaning that data is
+// sent as soon as possible after a Write.
+func (c *TCPConn) SetNoDelay(noDelay bool) error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return setNoDelay(c.fd, noDelay)
+}
+
+// DialTCP connects to the remote address raddr on the network net,
+// which must be "tcp", "tcp4", or "tcp6".  If laddr is not nil, it is
+// used as the local address for the connection.
+func DialTCP(net string, laddr, raddr *TCPAddr) (*TCPConn, error) {
+	switch net {
+	case "tcp", "tcp4", "tcp6":
+	default:
+		return nil, &OpError{Op: "dial", Net: net, Addr: raddr, Err: UnknownNetworkError(net)}
+	}
+	if raddr == nil {
+		return nil, &OpError{Op: "dial", Net: net, Addr: nil, Err: errMissingAddress}
+	}
+	return dialTCP(net, laddr, raddr, noDeadline)
+}
+
+func dialTCP(net string, laddr, raddr *TCPAddr, deadline time.Time) (*TCPConn, error) {
+	fd, err := internetSocket(net, laddr, raddr, deadline, syscall.SOCK_STREAM, 0, "dial")
+
+	// TCP has a rarely used mechanism called a 'simultaneous connection' in
+	// which Dial("tcp", addr1, addr2) run on the machine at addr1 can
+	// connect to a simultaneous Dial("tcp", addr2, addr1) run on the machine
+	// at addr2, without either machine executing Listen.  If laddr == nil,
+	// it means we want the kernel to pick an appropriate originating local
+	// address.  Some Linux kernels cycle blindly through a fixed range of
+	// local ports, regardless of destination port.  If a kernel happens to
+	// pick local port 50001 as the source for a Dial("tcp", "", "localhost:50001"),
+	// then the Dial will succeed, having simultaneously connected to itself.
+	// This can only happen when we are letting the kernel pick a port (laddr == nil)
+	// and when there is no listener for the destination address.
+	// It's hard to argue this is anything other than a kernel bug.  If we
+	// see this happen, rather than expose the buggy effect to users, we
+	// close the fd and try again.  If it happens twice more, we relent and
+	// use the result.  See also:
+	//	http://golang.org/issue/2690
+	//	http://stackoverflow.com/questions/4949858/
+	//
+	// The opposite can also happen: if we ask the kernel to pick an appropriate
+	// originating local address, sometimes it picks one that is already in use.
+	// So if the error is EADDRNOTAVAIL, we have to try again too, just for
+	// a different reason.
+	//
+	// The kernel socket code is no doubt enjoying watching us squirm.
+	for i := 0; i < 2 && (laddr == nil || laddr.Port == 0) && (selfConnect(fd, err) || spuriousENOTAVAIL(err)); i++ {
+		if err == nil {
+			fd.Close()
+		}
+		fd, err = internetSocket(net, laddr, raddr, deadline, syscall.SOCK_STREAM, 0, "dial")
+	}
+
+	if err != nil {
+		return nil, &OpError{Op: "dial", Net: net, Addr: raddr, Err: err}
+	}
+	return newTCPConn(fd), nil
+}
+
+func selfConnect(fd *netFD, err error) bool {
+	// If the connect failed, we clearly didn't connect to ourselves.
+	if err != nil {
+		return false
+	}
+
+	// The socket constructor can return an fd with raddr nil under certain
+	// unknown conditions. The errors in the calls there to Getpeername
+	// are discarded, but we can't catch the problem there because those
+	// calls are sometimes legally erroneous with a "socket not connected".
+	// Since this code (selfConnect) is already trying to work around
+	// a problem, we make sure if this happens we recognize trouble and
+	// ask the DialTCP routine to try again.
+	// TODO: try to understand what's really going on.
+	if fd.laddr == nil || fd.raddr == nil {
+		return true
+	}
+	l := fd.laddr.(*TCPAddr)
+	r := fd.raddr.(*TCPAddr)
+	return l.Port == r.Port && l.IP.Equal(r.IP)
+}
+
+func spuriousENOTAVAIL(err error) bool {
+	e, ok := err.(*OpError)
+	return ok && e.Err == syscall.EADDRNOTAVAIL
+}
+
+// TCPListener is a TCP network listener.  Clients should typically
+// use variables of type Listener instead of assuming TCP.
+type TCPListener struct {
+	fd *netFD
+}
+
+// AcceptTCP accepts the next incoming call and returns the new
+// connection.
+func (l *TCPListener) AcceptTCP() (*TCPConn, error) {
+	if l == nil || l.fd == nil {
+		return nil, syscall.EINVAL
+	}
+	fd, err := l.fd.accept()
+	if err != nil {
+		return nil, err
+	}
+	return newTCPConn(fd), nil
+}
+
+// Accept implements the Accept method in the Listener interface; it
+// waits for the next call and returns a generic Conn.
+func (l *TCPListener) Accept() (Conn, error) {
+	c, err := l.AcceptTCP()
+	if err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+// Close stops listening on the TCP address.
+// Already Accepted connections are not closed.
+func (l *TCPListener) Close() error {
+	if l == nil || l.fd == nil {
+		return syscall.EINVAL
+	}
+	return l.fd.Close()
+}
+
+// Addr returns the listener's network address, a *TCPAddr.
+func (l *TCPListener) Addr() Addr { return l.fd.laddr }
+
+// SetDeadline sets the deadline associated with the listener.
+// A zero time value disables the deadline.
+func (l *TCPListener) SetDeadline(t time.Time) error {
+	if l == nil || l.fd == nil {
+		return syscall.EINVAL
+	}
+	return l.fd.setDeadline(t)
+}
+
+// File returns a copy of the underlying os.File, set to blocking
+// mode.  It is the caller's responsibility to close f when finished.
+// Closing l does not affect f, and closing f does not affect l.
+//
+// The returned os.File's file descriptor is different from the
+// connection's.  Attempting to change properties of the original
+// using this duplicate may or may not have the desired effect.
+func (l *TCPListener) File() (f *os.File, err error) { return l.fd.dup() }
+
+// ListenTCP announces on the TCP address laddr and returns a TCP
+// listener.  Net must be "tcp", "tcp4", or "tcp6".  If laddr has a
+// port of 0, ListenTCP will choose an available port.  The caller can
+// use the Addr method of TCPListener to retrieve the chosen address.
+func ListenTCP(net string, laddr *TCPAddr) (*TCPListener, error) {
+	switch net {
+	case "tcp", "tcp4", "tcp6":
+	default:
+		return nil, &OpError{Op: "listen", Net: net, Addr: laddr, Err: UnknownNetworkError(net)}
+	}
+	if laddr == nil {
+		laddr = &TCPAddr{}
+	}
+	fd, err := internetSocket(net, laddr, nil, noDeadline, syscall.SOCK_STREAM, 0, "listen")
+	if err != nil {
+		return nil, &OpError{Op: "listen", Net: net, Addr: laddr, Err: err}
+	}
+	return &TCPListener{fd}, nil
+}