/usr/share/gocode/src/code.google.com/p/go.net/proxy/socks5.go is in golang-go.net-dev 0.0~hg20131201-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 | // Copyright 2011 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 proxy
import (
"errors"
"io"
"net"
"strconv"
)
// SOCKS5 returns a Dialer that makes SOCKSv5 connections to the given address
// with an optional username and password. See RFC 1928.
func SOCKS5(network, addr string, auth *Auth, forward Dialer) (Dialer, error) {
s := &socks5{
network: network,
addr: addr,
forward: forward,
}
if auth != nil {
s.user = auth.User
s.password = auth.Password
}
return s, nil
}
type socks5 struct {
user, password string
network, addr string
forward Dialer
}
const socks5Version = 5
const (
socks5AuthNone = 0
socks5AuthPassword = 2
)
const socks5Connect = 1
const (
socks5IP4 = 1
socks5Domain = 3
socks5IP6 = 4
)
var socks5Errors = []string{
"",
"general failure",
"connection forbidden",
"network unreachable",
"host unreachable",
"connection refused",
"TTL expired",
"command not supported",
"address type not supported",
}
// Dial connects to the address addr on the network net via the SOCKS5 proxy.
func (s *socks5) Dial(network, addr string) (net.Conn, error) {
switch network {
case "tcp", "tcp6", "tcp4":
default:
return nil, errors.New("proxy: no support for SOCKS5 proxy connections of type " + network)
}
conn, err := s.forward.Dial(s.network, s.addr)
if err != nil {
return nil, err
}
closeConn := &conn
defer func() {
if closeConn != nil {
(*closeConn).Close()
}
}()
host, portStr, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
port, err := strconv.Atoi(portStr)
if err != nil {
return nil, errors.New("proxy: failed to parse port number: " + portStr)
}
if port < 1 || port > 0xffff {
return nil, errors.New("proxy: port number out of range: " + portStr)
}
// the size here is just an estimate
buf := make([]byte, 0, 6+len(host))
buf = append(buf, socks5Version)
if len(s.user) > 0 && len(s.user) < 256 && len(s.password) < 256 {
buf = append(buf, 2 /* num auth methods */, socks5AuthNone, socks5AuthPassword)
} else {
buf = append(buf, 1 /* num auth methods */, socks5AuthNone)
}
if _, err := conn.Write(buf); err != nil {
return nil, errors.New("proxy: failed to write greeting to SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if _, err := io.ReadFull(conn, buf[:2]); err != nil {
return nil, errors.New("proxy: failed to read greeting from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if buf[0] != 5 {
return nil, errors.New("proxy: SOCKS5 proxy at " + s.addr + " has unexpected version " + strconv.Itoa(int(buf[0])))
}
if buf[1] == 0xff {
return nil, errors.New("proxy: SOCKS5 proxy at " + s.addr + " requires authentication")
}
if buf[1] == socks5AuthPassword {
buf = buf[:0]
buf = append(buf, 1 /* password protocol version */)
buf = append(buf, uint8(len(s.user)))
buf = append(buf, s.user...)
buf = append(buf, uint8(len(s.password)))
buf = append(buf, s.password...)
if _, err := conn.Write(buf); err != nil {
return nil, errors.New("proxy: failed to write authentication request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if _, err := io.ReadFull(conn, buf[:2]); err != nil {
return nil, errors.New("proxy: failed to read authentication reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if buf[1] != 0 {
return nil, errors.New("proxy: SOCKS5 proxy at " + s.addr + " rejected username/password")
}
}
buf = buf[:0]
buf = append(buf, socks5Version, socks5Connect, 0 /* reserved */)
if ip := net.ParseIP(host); ip != nil {
if ip4 := ip.To4(); ip4 != nil {
buf = append(buf, socks5IP4)
ip = ip4
} else {
buf = append(buf, socks5IP6)
}
buf = append(buf, ip...)
} else {
buf = append(buf, socks5Domain)
buf = append(buf, byte(len(host)))
buf = append(buf, host...)
}
buf = append(buf, byte(port>>8), byte(port))
if _, err := conn.Write(buf); err != nil {
return nil, errors.New("proxy: failed to write connect request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
if _, err := io.ReadFull(conn, buf[:4]); err != nil {
return nil, errors.New("proxy: failed to read connect reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
failure := "unknown error"
if int(buf[1]) < len(socks5Errors) {
failure = socks5Errors[buf[1]]
}
if len(failure) > 0 {
return nil, errors.New("proxy: SOCKS5 proxy at " + s.addr + " failed to connect: " + failure)
}
bytesToDiscard := 0
switch buf[3] {
case socks5IP4:
bytesToDiscard = net.IPv4len
case socks5IP6:
bytesToDiscard = net.IPv6len
case socks5Domain:
_, err := io.ReadFull(conn, buf[:1])
if err != nil {
return nil, errors.New("proxy: failed to read domain length from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
bytesToDiscard = int(buf[0])
default:
return nil, errors.New("proxy: got unknown address type " + strconv.Itoa(int(buf[3])) + " from SOCKS5 proxy at " + s.addr)
}
if cap(buf) < bytesToDiscard {
buf = make([]byte, bytesToDiscard)
} else {
buf = buf[:bytesToDiscard]
}
if _, err := io.ReadFull(conn, buf); err != nil {
return nil, errors.New("proxy: failed to read address from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
// Also need to discard the port number
if _, err := io.ReadFull(conn, buf[:2]); err != nil {
return nil, errors.New("proxy: failed to read port from SOCKS5 proxy at " + s.addr + ": " + err.Error())
}
closeConn = nil
return conn, nil
}
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