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jeremybenn |
// 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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var supportsIPv6, supportsIPv4map = probeIPv6Stack()
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func firstFavoriteAddr(filter func(IP) IP, addrs []string) (addr IP) {
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if filter == nil {
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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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func firstSupportedAddr(filter func(IP) IP, addrs []string) IP {
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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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}
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}
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return nil
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}
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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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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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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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}
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type InvalidAddrError string
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func (e InvalidAddrError) Error() 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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// 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 error) {
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// The port starts after the last colon.
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i := last(hostport, ':')
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if i < 0 {
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err = &AddrError{"missing port in address", hostport}
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return
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}
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host, port = hostport[0:i], hostport[i+1:]
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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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host = host[1 : len(host)-1]
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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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err = &AddrError{"too many colons in address", hostport}
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return
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}
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}
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return
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}
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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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// If host has colons, have to bracket it.
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if byteIndex(host, ':') >= 0 {
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return "[" + host + "]:" + port
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}
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return host + ":" + port
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}
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// Convert "host:port" into IP address and port.
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func hostPortToIP(net, hostport string) (ip IP, iport int, err error) {
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host, port, err := SplitHostPort(hostport)
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if err != nil {
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return nil, 0, err
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}
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var addr IP
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if host != "" {
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// Try as an IP address.
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addr = ParseIP(host)
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if addr == nil {
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var filter func(IP) IP
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if net != "" && net[len(net)-1] == '4' {
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filter = ipv4only
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}
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if net != "" && net[len(net)-1] == '6' {
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filter = ipv6only
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}
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// Not an IP address. Try as a DNS name.
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addrs, err := LookupHost(host)
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if err != nil {
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return nil, 0, err
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}
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addr = firstFavoriteAddr(filter, addrs)
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if addr == nil {
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// should not happen
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return nil, 0, &AddrError{"LookupHost returned no suitable address", addrs[0]}
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}
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}
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}
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p, i, ok := dtoi(port, 0)
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if !ok || i != len(port) {
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p, err = LookupPort(net, port)
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if err != nil {
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return nil, 0, err
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}
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}
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if p < 0 || p > 0xFFFF {
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return nil, 0, &AddrError{"invalid port", port}
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}
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return addr, p, nil
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}
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