| // 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) |
| } |