2009-11-01 12:15:34 -07:00
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// Copyright 2009 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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// IP sockets
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package net
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import (
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2009-12-15 16:35:38 -07:00
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"os"
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"syscall"
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2009-11-01 12:15:34 -07:00
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)
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// Should we try to use the IPv4 socket interface if we're
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// only dealing with IPv4 sockets? As long as the host system
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// understands IPv6, it's okay to pass IPv4 addresses to the IPv6
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// interface. That simplifies our code and is most general.
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2011-05-16 15:03:06 -06:00
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// Unfortunately, we need to run on kernels built without IPv6
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// support too. So probe the kernel to figure it out.
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//
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// probeIPv6Stack probes both basic IPv6 capability and IPv6 IPv4-
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// mapping capability which is controlled by IPV6_V6ONLY socket
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// option and/or kernel state "net.inet6.ip6.v6only".
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// It returns two boolean values. If the first boolean value is
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// true, kernel supports basic IPv6 functionality. If the second
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// boolean value is true, kernel supports IPv6 IPv4-mapping.
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func probeIPv6Stack() (supportsIPv6, supportsIPv4map bool) {
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var probes = []struct {
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s int
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la TCPAddr
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ok bool
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}{
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// IPv6 communication capability
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{-1, TCPAddr{IP: ParseIP("::1")}, false},
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// IPv6 IPv4-mapped address communication capability
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{-1, TCPAddr{IP: IPv4(127, 0, 0, 1)}, false},
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}
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var errno int
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2011-05-16 15:03:06 -06:00
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for i := range probes {
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probes[i].s, errno = syscall.Socket(syscall.AF_INET6, syscall.SOCK_STREAM, syscall.IPPROTO_TCP)
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if errno != 0 {
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continue
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}
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defer closesocket(probes[i].s)
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sa, err := probes[i].la.toAddr().sockaddr(syscall.AF_INET6)
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if err != nil {
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continue
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}
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errno = syscall.Bind(probes[i].s, sa)
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if errno != 0 {
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continue
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}
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probes[i].ok = true
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}
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2011-05-16 15:03:06 -06:00
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return probes[0].ok, probes[1].ok
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}
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var supportsIPv6, supportsIPv4map = probeIPv6Stack()
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func favoriteAddrFamily(net string, raddr, laddr sockaddr) (family int) {
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// Figure out IP version.
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// If network has a suffix like "tcp4", obey it.
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family = syscall.AF_INET6
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switch net[len(net)-1] {
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case '4':
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family = syscall.AF_INET
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case '6':
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// nothing to do
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default:
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// Otherwise, guess.
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// If the addresses are IPv4, use 4; else 6.
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if (laddr == nil || laddr.family() == syscall.AF_INET) &&
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(raddr == nil || raddr.family() == syscall.AF_INET) {
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family = syscall.AF_INET
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}
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}
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return
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2009-11-01 12:15:34 -07:00
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}
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2011-05-16 15:03:06 -06:00
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func firstFavoriteAddr(filter func(IP) IP, addrs []string) (addr IP) {
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if filter == anyaddr {
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// We'll take any IP address, but since the dialing code
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// does not yet try multiple addresses, prefer to use
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// an IPv4 address if possible. This is especially relevant
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// if localhost resolves to [ipv6-localhost, ipv4-localhost].
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// Too much code assumes localhost == ipv4-localhost.
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addr = firstSupportedAddr(ipv4only, addrs)
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if addr == nil {
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addr = firstSupportedAddr(anyaddr, addrs)
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}
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} else {
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addr = firstSupportedAddr(filter, addrs)
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}
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return
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}
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2011-04-20 13:21:59 -06:00
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func firstSupportedAddr(filter func(IP) IP, addrs []string) IP {
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2011-02-16 13:05:48 -07:00
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for _, s := range addrs {
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if addr := filter(ParseIP(s)); addr != nil {
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return addr
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2011-02-16 13:05:48 -07:00
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}
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}
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return nil
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}
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2011-05-16 15:03:06 -06:00
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func anyaddr(x IP) IP {
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if x4 := x.To4(); x4 != nil {
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return x4
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}
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if supportsIPv6 {
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return x
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}
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return nil
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}
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2011-04-20 13:21:59 -06:00
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func ipv4only(x IP) IP { return x.To4() }
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func ipv6only(x IP) IP {
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// Only return addresses that we can use
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// with the kernel's IPv6 addressing modes.
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2011-05-16 15:03:06 -06:00
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if len(x) == IPv6len && x.To4() == nil && supportsIPv6 {
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return x
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}
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return nil
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2011-02-16 13:05:48 -07:00
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}
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2009-11-01 12:15:34 -07:00
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// TODO(rsc): if syscall.OS == "linux", we're supposd to read
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// /proc/sys/net/core/somaxconn,
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// to take advantage of kernels that have raised the limit.
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func listenBacklog() int { return syscall.SOMAXCONN }
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2009-11-01 12:15:34 -07:00
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// Internet sockets (TCP, UDP)
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2009-11-02 19:37:30 -07:00
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// A sockaddr represents a TCP or UDP network address that can
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// be converted into a syscall.Sockaddr.
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type sockaddr interface {
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2009-12-15 16:35:38 -07:00
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Addr
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sockaddr(family int) (syscall.Sockaddr, os.Error)
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family() int
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}
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2009-11-01 12:15:34 -07:00
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2010-05-21 18:30:40 -06:00
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func internetSocket(net string, laddr, raddr sockaddr, socktype, proto int, mode string, toAddr func(syscall.Sockaddr) Addr) (fd *netFD, err os.Error) {
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// Figure out IP version.
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// If network has a suffix like "tcp4", obey it.
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2010-04-26 23:15:25 -06:00
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var oserr os.Error
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var la, ra syscall.Sockaddr
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family := favoriteAddrFamily(net, raddr, laddr)
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2009-11-02 19:37:30 -07:00
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if laddr != nil {
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2010-08-22 06:12:56 -06:00
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if la, oserr = laddr.sockaddr(family); oserr != nil {
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2009-11-09 13:07:39 -07:00
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goto Error
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2009-11-01 12:15:34 -07:00
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}
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}
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2009-11-02 19:37:30 -07:00
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if raddr != nil {
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2010-08-22 06:12:56 -06:00
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if ra, oserr = raddr.sockaddr(family); oserr != nil {
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2009-11-09 13:07:39 -07:00
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goto Error
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2009-11-01 12:15:34 -07:00
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}
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}
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2010-05-21 18:30:40 -06:00
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fd, oserr = socket(net, family, socktype, proto, la, ra, toAddr)
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2010-04-27 19:48:11 -06:00
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if oserr != nil {
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2009-11-09 13:07:39 -07:00
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goto Error
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2009-11-01 12:15:34 -07:00
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}
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2009-12-15 16:35:38 -07:00
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return fd, nil
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2009-11-01 12:15:34 -07:00
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Error:
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2009-12-15 16:35:38 -07:00
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addr := raddr
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2009-11-01 12:15:34 -07:00
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if mode == "listen" {
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2009-11-09 13:07:39 -07:00
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addr = laddr
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2009-11-01 12:15:34 -07:00
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}
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2010-04-26 23:15:25 -06:00
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return nil, &OpError{mode, net, addr, oserr}
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2009-11-01 12:15:34 -07:00
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}
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2010-04-26 23:15:25 -06:00
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type InvalidAddrError string
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func (e InvalidAddrError) String() string { return string(e) }
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func (e InvalidAddrError) Timeout() bool { return false }
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func (e InvalidAddrError) Temporary() bool { return false }
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2009-11-01 12:15:34 -07:00
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func ipToSockaddr(family int, ip IP, port int) (syscall.Sockaddr, os.Error) {
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switch family {
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case syscall.AF_INET:
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2009-11-02 19:37:30 -07:00
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if len(ip) == 0 {
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2009-11-09 13:07:39 -07:00
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ip = IPv4zero
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2009-11-02 19:37:30 -07:00
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}
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2009-11-01 12:15:34 -07:00
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if ip = ip.To4(); ip == nil {
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2010-04-26 23:15:25 -06:00
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return nil, InvalidAddrError("non-IPv4 address")
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2009-11-01 12:15:34 -07:00
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}
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2009-12-15 16:35:38 -07:00
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s := new(syscall.SockaddrInet4)
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2009-11-01 12:15:34 -07:00
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for i := 0; i < IPv4len; i++ {
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2009-11-09 13:07:39 -07:00
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s.Addr[i] = ip[i]
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2009-11-01 12:15:34 -07:00
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}
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2009-12-15 16:35:38 -07:00
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s.Port = port
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return s, nil
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2009-11-01 12:15:34 -07:00
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case syscall.AF_INET6:
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2009-11-02 19:37:30 -07:00
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if len(ip) == 0 {
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2011-05-16 15:03:06 -06:00
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ip = IPv6zero
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2009-11-02 19:37:30 -07:00
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}
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2009-11-01 12:15:34 -07:00
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// IPv4 callers use 0.0.0.0 to mean "announce on any available address".
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// In IPv6 mode, Linux treats that as meaning "announce on 0.0.0.0",
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// which it refuses to do. Rewrite to the IPv6 all zeros.
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2011-05-16 15:03:06 -06:00
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if ip.Equal(IPv4zero) {
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ip = IPv6zero
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2009-11-01 12:15:34 -07:00
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}
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if ip = ip.To16(); ip == nil {
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2010-04-26 23:15:25 -06:00
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return nil, InvalidAddrError("non-IPv6 address")
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2009-11-01 12:15:34 -07:00
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}
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2009-12-15 16:35:38 -07:00
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s := new(syscall.SockaddrInet6)
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2009-11-01 12:15:34 -07:00
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for i := 0; i < IPv6len; i++ {
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2009-11-09 13:07:39 -07:00
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s.Addr[i] = ip[i]
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2009-11-01 12:15:34 -07:00
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}
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2009-12-15 16:35:38 -07:00
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s.Port = port
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return s, nil
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2009-11-01 12:15:34 -07:00
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}
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2010-04-26 23:15:25 -06:00
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return nil, InvalidAddrError("unexpected socket family")
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2009-11-01 12:15:34 -07:00
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}
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2011-03-28 21:28:42 -06:00
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// SplitHostPort splits a network address of the form
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// "host:port" or "[host]:port" into host and port.
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// The latter form must be used when host contains a colon.
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func SplitHostPort(hostport string) (host, port string, err os.Error) {
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2009-11-01 12:15:34 -07:00
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// The port starts after the last colon.
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2009-12-15 16:35:38 -07:00
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i := last(hostport, ':')
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2009-11-01 12:15:34 -07:00
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if i < 0 {
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2009-12-15 16:35:38 -07:00
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err = &AddrError{"missing port in address", hostport}
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return
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2009-11-01 12:15:34 -07:00
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}
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2009-12-15 16:35:38 -07:00
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host, port = hostport[0:i], hostport[i+1:]
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2009-11-01 12:15:34 -07:00
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// Can put brackets around host ...
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if len(host) > 0 && host[0] == '[' && host[len(host)-1] == ']' {
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2009-11-09 13:07:39 -07:00
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host = host[1 : len(host)-1]
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2009-11-01 12:15:34 -07:00
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} else {
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// ... but if there are no brackets, no colons.
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if byteIndex(host, ':') >= 0 {
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2009-12-15 16:35:38 -07:00
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err = &AddrError{"too many colons in address", hostport}
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return
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2009-11-01 12:15:34 -07:00
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}
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}
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2009-12-15 16:35:38 -07:00
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return
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2009-11-01 12:15:34 -07:00
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}
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2011-03-28 21:28:42 -06:00
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// JoinHostPort combines host and port into a network address
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// of the form "host:port" or, if host contains a colon, "[host]:port".
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func JoinHostPort(host, port string) string {
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2009-11-01 12:15:34 -07:00
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// If host has colons, have to bracket it.
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if byteIndex(host, ':') >= 0 {
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2009-11-09 22:23:52 -07:00
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return "[" + host + "]:" + port
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2009-11-01 12:15:34 -07:00
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}
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2009-12-15 16:35:38 -07:00
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return host + ":" + port
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2009-11-01 12:15:34 -07:00
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}
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// Convert "host:port" into IP address and port.
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2009-11-02 19:37:30 -07:00
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func hostPortToIP(net, hostport string) (ip IP, iport int, err os.Error) {
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2011-03-28 21:28:42 -06:00
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host, port, err := SplitHostPort(hostport)
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2009-11-01 12:15:34 -07:00
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if err != nil {
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2009-11-09 13:07:39 -07:00
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goto Error
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2009-11-01 12:15:34 -07:00
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}
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2009-12-15 16:35:38 -07:00
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var addr IP
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2009-11-02 19:37:30 -07:00
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if host != "" {
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// Try as an IP address.
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2009-12-15 16:35:38 -07:00
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addr = ParseIP(host)
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2009-11-01 12:15:34 -07:00
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if addr == nil {
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2011-04-20 13:21:59 -06:00
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filter := anyaddr
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2011-05-16 15:03:06 -06:00
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if net != "" && net[len(net)-1] == '4' {
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2011-04-20 13:21:59 -06:00
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filter = ipv4only
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2011-05-16 15:03:06 -06:00
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}
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if net != "" && net[len(net)-1] == '6' {
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2011-04-20 13:21:59 -06:00
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filter = ipv6only
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}
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2009-11-02 19:37:30 -07:00
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// Not an IP address. Try as a DNS name.
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2011-03-28 21:28:42 -06:00
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addrs, err1 := LookupHost(host)
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2009-11-02 19:37:30 -07:00
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if err1 != nil {
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2009-12-15 16:35:38 -07:00
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err = err1
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goto Error
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2009-11-02 19:37:30 -07:00
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}
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2011-05-16 15:03:06 -06:00
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addr = firstFavoriteAddr(filter, addrs)
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2009-11-02 19:37:30 -07:00
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if addr == nil {
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// should not happen
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2011-05-16 15:03:06 -06:00
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err = &AddrError{"LookupHost returned no suitable address", addrs[0]}
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2009-12-15 16:35:38 -07:00
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goto Error
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2009-11-02 19:37:30 -07:00
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}
|
2009-11-01 12:15:34 -07:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2009-12-15 16:35:38 -07:00
|
|
|
p, i, ok := dtoi(port, 0)
|
2009-11-01 12:15:34 -07:00
|
|
|
if !ok || i != len(port) {
|
2009-12-15 16:35:38 -07:00
|
|
|
p, err = LookupPort(net, port)
|
2009-11-01 12:15:34 -07:00
|
|
|
if err != nil {
|
2009-11-09 13:07:39 -07:00
|
|
|
goto Error
|
2009-11-01 12:15:34 -07:00
|
|
|
}
|
|
|
|
}
|
|
|
|
if p < 0 || p > 0xFFFF {
|
2009-12-15 16:35:38 -07:00
|
|
|
err = &AddrError{"invalid port", port}
|
|
|
|
goto Error
|
2009-11-01 12:15:34 -07:00
|
|
|
}
|
|
|
|
|
2009-12-15 16:35:38 -07:00
|
|
|
return addr, p, nil
|
2009-11-01 12:15:34 -07:00
|
|
|
|
|
|
|
Error:
|
2009-12-15 16:35:38 -07:00
|
|
|
return nil, 0, err
|
2009-11-01 12:15:34 -07:00
|
|
|
}
|