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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 resolveNetAddr(op, net, addr string) (a Addr, err error) {
if addr == "" {
return nil, &OpError{op, net, nil, errMissingAddress}
}
switch net {
case "tcp", "tcp4", "tcp6":
a, err = ResolveTCPAddr(net, addr)
case "udp", "udp4", "udp6":
a, err = ResolveUDPAddr(net, addr)
case "unix", "unixgram", "unixpacket":
a, err = ResolveUnixAddr(net, addr)
case "ip", "ip4", "ip6":
a, err = ResolveIPAddr(net, addr)
default:
err = UnknownNetworkError(net)
}
if err != nil {
return nil, &OpError{op, net + " " + addr, nil, err}
}
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" and "unixgram".
//
// For IP 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")
//
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 *UnixAddr:
c, err = DialUnix(net, nil, ra)
case *IPAddr:
c, err = DialIP(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) (l Listener, err error) {
switch net {
case "tcp", "tcp4", "tcp6":
var la *TCPAddr
if laddr != "" {
if la, err = ResolveTCPAddr(net, laddr); err != nil {
return nil, err
}
}
l, err := ListenTCP(net, la)
if err != nil {
return nil, err
}
return l, nil
case "unix", "unixpacket":
var la *UnixAddr
if laddr != "" {
if la, err = ResolveUnixAddr(net, laddr); err != nil {
return nil, err
}
}
l, err := ListenUnix(net, la)
if err != nil {
return nil, err
}
return l, nil
}
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", or "unixgram".
func ListenPacket(net, laddr string) (c PacketConn, err error) {
switch net {
case "udp", "udp4", "udp6":
var la *UDPAddr
if laddr != "" {
if la, err = ResolveUDPAddr(net, laddr); err != nil {
return nil, err
}
}
c, err := ListenUDP(net, la)
if err != nil {
return nil, err
}
return c, nil
case "unixgram":
var la *UnixAddr
if laddr != "" {
if la, err = ResolveUnixAddr(net, laddr); err != nil {
return nil, err
}
}
c, err := DialUnix(net, la, nil)
if err != nil {
return nil, err
}
return c, nil
}
var rawnet string
if rawnet, _, err = splitNetProto(net); err != nil {
switch rawnet {
case "ip", "ip4", "ip6":
var la *IPAddr
if laddr != "" {
if la, err = ResolveIPAddr(rawnet, laddr); err != nil {
return nil, err
}
}
c, err := ListenIP(net, la)
if err != nil {
return nil, err
}
return c, nil
}
}
return nil, UnknownNetworkError(net)
}
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