diff options
Diffstat (limited to 'vendor/golang.org/x/net/proxy/socks5.go')
| -rw-r--r-- | vendor/golang.org/x/net/proxy/socks5.go | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/vendor/golang.org/x/net/proxy/socks5.go b/vendor/golang.org/x/net/proxy/socks5.go new file mode 100644 index 0000000..973f57f --- /dev/null +++ b/vendor/golang.org/x/net/proxy/socks5.go @@ -0,0 +1,213 @@ +// 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 + } + if err := s.connect(conn, addr); err != nil { + conn.Close() + return nil, err + } + return conn, nil +} + +// connect takes an existing connection to a socks5 proxy server, +// and commands the server to extend that connection to target, +// which must be a canonical address with a host and port. +func (s *socks5) connect(conn net.Conn, target string) error { + host, portStr, err := net.SplitHostPort(target) + if err != nil { + return err + } + + port, err := strconv.Atoi(portStr) + if err != nil { + return errors.New("proxy: failed to parse port number: " + portStr) + } + if port < 1 || port > 0xffff { + return 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 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 errors.New("proxy: failed to read greeting from SOCKS5 proxy at " + s.addr + ": " + err.Error()) + } + if buf[0] != 5 { + return errors.New("proxy: SOCKS5 proxy at " + s.addr + " has unexpected version " + strconv.Itoa(int(buf[0]))) + } + if buf[1] == 0xff { + return 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 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 errors.New("proxy: failed to read authentication reply from SOCKS5 proxy at " + s.addr + ": " + err.Error()) + } + + if buf[1] != 0 { + return 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 { + if len(host) > 255 { + return errors.New("proxy: destination hostname too long: " + host) + } + 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 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 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 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 errors.New("proxy: failed to read domain length from SOCKS5 proxy at " + s.addr + ": " + err.Error()) + } + bytesToDiscard = int(buf[0]) + default: + return 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 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 errors.New("proxy: failed to read port from SOCKS5 proxy at " + s.addr + ": " + err.Error()) + } + + return nil +} |