4ccad563d2
From-SVN: r192704
229 lines
5.5 KiB
Go
229 lines
5.5 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package net
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import (
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"time"
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)
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func parseDialNetwork(net string) (afnet string, proto int, err error) {
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i := last(net, ':')
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if i < 0 { // no colon
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switch net {
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case "tcp", "tcp4", "tcp6":
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case "udp", "udp4", "udp6":
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case "unix", "unixgram", "unixpacket":
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default:
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return "", 0, UnknownNetworkError(net)
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}
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return net, 0, nil
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}
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afnet = net[:i]
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switch afnet {
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case "ip", "ip4", "ip6":
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protostr := net[i+1:]
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proto, i, ok := dtoi(protostr, 0)
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if !ok || i != len(protostr) {
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proto, err = lookupProtocol(protostr)
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if err != nil {
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return "", 0, err
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}
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}
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return afnet, proto, nil
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}
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return "", 0, UnknownNetworkError(net)
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}
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func resolveNetAddr(op, net, addr string) (afnet string, a Addr, err error) {
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afnet, _, err = parseDialNetwork(net)
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if err != nil {
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return "", nil, &OpError{op, net, nil, err}
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}
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if op == "dial" && addr == "" {
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return "", nil, &OpError{op, net, nil, errMissingAddress}
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}
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switch afnet {
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case "tcp", "tcp4", "tcp6":
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if addr != "" {
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a, err = ResolveTCPAddr(afnet, addr)
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}
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case "udp", "udp4", "udp6":
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if addr != "" {
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a, err = ResolveUDPAddr(afnet, addr)
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}
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case "ip", "ip4", "ip6":
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if addr != "" {
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a, err = ResolveIPAddr(afnet, addr)
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}
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case "unix", "unixgram", "unixpacket":
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if addr != "" {
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a, err = ResolveUnixAddr(afnet, addr)
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}
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}
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return
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}
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// Dial connects to the address addr on the network net.
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//
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// Known networks are "tcp", "tcp4" (IPv4-only), "tcp6" (IPv6-only),
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// "udp", "udp4" (IPv4-only), "udp6" (IPv6-only), "ip", "ip4"
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// (IPv4-only), "ip6" (IPv6-only), "unix" and "unixpacket".
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//
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// For TCP and UDP networks, addresses have the form host:port.
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// If host is a literal IPv6 address, it must be enclosed
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// in square brackets. The functions JoinHostPort and SplitHostPort
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// manipulate addresses in this form.
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//
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// Examples:
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// Dial("tcp", "12.34.56.78:80")
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// Dial("tcp", "google.com:80")
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// Dial("tcp", "[de:ad:be:ef::ca:fe]:80")
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//
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// For IP networks, net must be "ip", "ip4" or "ip6" followed
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// by a colon and a protocol number or name.
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//
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// Examples:
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// Dial("ip4:1", "127.0.0.1")
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// Dial("ip6:ospf", "::1")
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//
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func Dial(net, addr string) (Conn, error) {
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_, addri, err := resolveNetAddr("dial", net, addr)
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if err != nil {
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return nil, err
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}
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return dialAddr(net, addr, addri)
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}
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func dialAddr(net, addr string, addri Addr) (c Conn, err error) {
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switch ra := addri.(type) {
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case *TCPAddr:
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c, err = DialTCP(net, nil, ra)
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case *UDPAddr:
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c, err = DialUDP(net, nil, ra)
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case *IPAddr:
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c, err = DialIP(net, nil, ra)
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case *UnixAddr:
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c, err = DialUnix(net, nil, ra)
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default:
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err = &OpError{"dial", net + " " + addr, nil, UnknownNetworkError(net)}
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}
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if err != nil {
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return nil, err
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}
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return
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}
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// DialTimeout acts like Dial but takes a timeout.
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// The timeout includes name resolution, if required.
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func DialTimeout(net, addr string, timeout time.Duration) (Conn, error) {
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// TODO(bradfitz): the timeout should be pushed down into the
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// net package's event loop, so on timeout to dead hosts we
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// don't have a goroutine sticking around for the default of
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// ~3 minutes.
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t := time.NewTimer(timeout)
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defer t.Stop()
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type pair struct {
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Conn
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error
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}
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ch := make(chan pair, 1)
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resolvedAddr := make(chan Addr, 1)
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go func() {
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_, addri, err := resolveNetAddr("dial", net, addr)
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if err != nil {
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ch <- pair{nil, err}
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return
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}
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resolvedAddr <- addri // in case we need it for OpError
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c, err := dialAddr(net, addr, addri)
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ch <- pair{c, err}
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}()
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select {
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case <-t.C:
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// Try to use the real Addr in our OpError, if we resolved it
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// before the timeout. Otherwise we just use stringAddr.
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var addri Addr
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select {
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case a := <-resolvedAddr:
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addri = a
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default:
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addri = &stringAddr{net, addr}
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}
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err := &OpError{
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Op: "dial",
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Net: net,
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Addr: addri,
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Err: &timeoutError{},
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}
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return nil, err
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case p := <-ch:
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return p.Conn, p.error
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}
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panic("unreachable")
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}
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type stringAddr struct {
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net, addr string
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}
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func (a stringAddr) Network() string { return a.net }
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func (a stringAddr) String() string { return a.addr }
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// Listen announces on the local network address laddr.
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// The network string net must be a stream-oriented network:
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// "tcp", "tcp4", "tcp6", "unix" or "unixpacket".
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func Listen(net, laddr string) (Listener, error) {
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afnet, a, err := resolveNetAddr("listen", net, laddr)
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if err != nil {
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return nil, err
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}
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switch afnet {
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case "tcp", "tcp4", "tcp6":
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var la *TCPAddr
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if a != nil {
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la = a.(*TCPAddr)
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}
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return ListenTCP(net, la)
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case "unix", "unixpacket":
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var la *UnixAddr
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if a != nil {
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la = a.(*UnixAddr)
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}
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return ListenUnix(net, la)
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}
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return nil, UnknownNetworkError(net)
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}
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// ListenPacket announces on the local network address laddr.
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// The network string net must be a packet-oriented network:
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// "udp", "udp4", "udp6", "ip", "ip4", "ip6" or "unixgram".
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func ListenPacket(net, addr string) (PacketConn, error) {
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afnet, a, err := resolveNetAddr("listen", net, addr)
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if err != nil {
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return nil, err
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}
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switch afnet {
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case "udp", "udp4", "udp6":
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var la *UDPAddr
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if a != nil {
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la = a.(*UDPAddr)
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}
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return ListenUDP(net, la)
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case "ip", "ip4", "ip6":
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var la *IPAddr
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if a != nil {
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la = a.(*IPAddr)
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}
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return ListenIP(net, la)
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case "unixgram":
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var la *UnixAddr
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if a != nil {
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la = a.(*UnixAddr)
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}
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return DialUnix(net, la, nil)
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}
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return nil, UnknownNetworkError(net)
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}
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