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