Add SOCKS5 support

- Bundle the golang.org/x/net/proxy package to x_net_proxy.go. The
package contains a SOCKS5 proxy. The package is bundled to avoid adding
a dependency from the weboscket package to golang.org/x/net.
- Restructure the existing HTTP proxy code so the code can be used as a
dialer with the proxy package.
- Modify Dialer.Dial to use proxy.FromURL.
- Improve tests (avoid modifying package-level data, use timeouts in
tests, use correct proxy URLs in tests).

Fixes #297.
This commit is contained in:
Gary Burd 2017-11-30 17:43:01 -08:00 committed by GitHub
parent 8c6cfd493d
commit b89020ee79
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 677 additions and 67 deletions

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@ -5,10 +5,8 @@
package websocket package websocket
import ( import (
"bufio"
"bytes" "bytes"
"crypto/tls" "crypto/tls"
"encoding/base64"
"errors" "errors"
"io" "io"
"io/ioutil" "io/ioutil"
@ -106,7 +104,7 @@ func hostPortNoPort(u *url.URL) (hostPort, hostNoPort string) {
return hostPort, hostNoPort return hostPort, hostNoPort
} }
// DefaultDialer is a dialer with all fields set to the default zero values. // DefaultDialer is a dialer with all fields set to the default values.
var DefaultDialer = &Dialer{ var DefaultDialer = &Dialer{
Proxy: http.ProxyFromEnvironment, Proxy: http.ProxyFromEnvironment,
} }
@ -202,36 +200,52 @@ func (d *Dialer) Dial(urlStr string, requestHeader http.Header) (*Conn, *http.Re
req.Header.Set("Sec-Websocket-Extensions", "permessage-deflate; server_no_context_takeover; client_no_context_takeover") req.Header.Set("Sec-Websocket-Extensions", "permessage-deflate; server_no_context_takeover; client_no_context_takeover")
} }
hostPort, hostNoPort := hostPortNoPort(u)
var proxyURL *url.URL
// Check wether the proxy method has been configured
if d.Proxy != nil {
proxyURL, err = d.Proxy(req)
}
if err != nil {
return nil, nil, err
}
var targetHostPort string
if proxyURL != nil {
targetHostPort, _ = hostPortNoPort(proxyURL)
} else {
targetHostPort = hostPort
}
var deadline time.Time var deadline time.Time
if d.HandshakeTimeout != 0 { if d.HandshakeTimeout != 0 {
deadline = time.Now().Add(d.HandshakeTimeout) deadline = time.Now().Add(d.HandshakeTimeout)
} }
// Get network dial function.
netDial := d.NetDial netDial := d.NetDial
if netDial == nil { if netDial == nil {
netDialer := &net.Dialer{Deadline: deadline} netDialer := &net.Dialer{Deadline: deadline}
netDial = netDialer.Dial netDial = netDialer.Dial
} }
netConn, err := netDial("tcp", targetHostPort) // If needed, wrap the dial function to set the connection deadline.
if !deadline.Equal(time.Time{}) {
forwardDial := netDial
netDial = func(network, addr string) (net.Conn, error) {
c, err := forwardDial(network, addr)
if err != nil {
return nil, err
}
err = c.SetDeadline(deadline)
if err != nil {
c.Close()
return nil, err
}
return c, nil
}
}
// If needed, wrap the dial function to connect through a proxy.
if d.Proxy != nil {
proxyURL, err := d.Proxy(req)
if err != nil {
return nil, nil, err
}
if proxyURL != nil {
dialer, err := proxy_FromURL(proxyURL, netDialerFunc(netDial))
if err != nil {
return nil, nil, err
}
netDial = dialer.Dial
}
}
hostPort, hostNoPort := hostPortNoPort(u)
netConn, err := netDial("tcp", hostPort)
if err != nil { if err != nil {
return nil, nil, err return nil, nil, err
} }
@ -242,42 +256,6 @@ func (d *Dialer) Dial(urlStr string, requestHeader http.Header) (*Conn, *http.Re
} }
}() }()
if err := netConn.SetDeadline(deadline); err != nil {
return nil, nil, err
}
if proxyURL != nil {
connectHeader := make(http.Header)
if user := proxyURL.User; user != nil {
proxyUser := user.Username()
if proxyPassword, passwordSet := user.Password(); passwordSet {
credential := base64.StdEncoding.EncodeToString([]byte(proxyUser + ":" + proxyPassword))
connectHeader.Set("Proxy-Authorization", "Basic "+credential)
}
}
connectReq := &http.Request{
Method: "CONNECT",
URL: &url.URL{Opaque: hostPort},
Host: hostPort,
Header: connectHeader,
}
connectReq.Write(netConn)
// Read response.
// Okay to use and discard buffered reader here, because
// TLS server will not speak until spoken to.
br := bufio.NewReader(netConn)
resp, err := http.ReadResponse(br, connectReq)
if err != nil {
return nil, nil, err
}
if resp.StatusCode != 200 {
f := strings.SplitN(resp.Status, " ", 2)
return nil, nil, errors.New(f[1])
}
}
if u.Scheme == "https" { if u.Scheme == "https" {
cfg := cloneTLSConfig(d.TLSClientConfig) cfg := cloneTLSConfig(d.TLSClientConfig)
if cfg.ServerName == "" { if cfg.ServerName == "" {

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@ -5,11 +5,14 @@
package websocket package websocket
import ( import (
"bytes"
"crypto/tls" "crypto/tls"
"crypto/x509" "crypto/x509"
"encoding/base64" "encoding/base64"
"encoding/binary"
"io" "io"
"io/ioutil" "io/ioutil"
"net"
"net/http" "net/http"
"net/http/cookiejar" "net/http/cookiejar"
"net/http/httptest" "net/http/httptest"
@ -34,6 +37,7 @@ var cstDialer = Dialer{
Subprotocols: []string{"p1", "p2"}, Subprotocols: []string{"p1", "p2"},
ReadBufferSize: 1024, ReadBufferSize: 1024,
WriteBufferSize: 1024, WriteBufferSize: 1024,
HandshakeTimeout: 30 * time.Second,
} }
type cstHandler struct{ *testing.T } type cstHandler struct{ *testing.T }
@ -143,8 +147,9 @@ func TestProxyDial(t *testing.T) {
s := newServer(t) s := newServer(t)
defer s.Close() defer s.Close()
surl, _ := url.Parse(s.URL) surl, _ := url.Parse(s.Server.URL)
cstDialer := cstDialer // make local copy for modification on next line.
cstDialer.Proxy = http.ProxyURL(surl) cstDialer.Proxy = http.ProxyURL(surl)
connect := false connect := false
@ -173,16 +178,16 @@ func TestProxyDial(t *testing.T) {
} }
defer ws.Close() defer ws.Close()
sendRecv(t, ws) sendRecv(t, ws)
cstDialer.Proxy = http.ProxyFromEnvironment
} }
func TestProxyAuthorizationDial(t *testing.T) { func TestProxyAuthorizationDial(t *testing.T) {
s := newServer(t) s := newServer(t)
defer s.Close() defer s.Close()
surl, _ := url.Parse(s.URL) surl, _ := url.Parse(s.Server.URL)
surl.User = url.UserPassword("username", "password") surl.User = url.UserPassword("username", "password")
cstDialer := cstDialer // make local copy for modification on next line.
cstDialer.Proxy = http.ProxyURL(surl) cstDialer.Proxy = http.ProxyURL(surl)
connect := false connect := false
@ -213,8 +218,6 @@ func TestProxyAuthorizationDial(t *testing.T) {
} }
defer ws.Close() defer ws.Close()
sendRecv(t, ws) sendRecv(t, ws)
cstDialer.Proxy = http.ProxyFromEnvironment
} }
func TestDial(t *testing.T) { func TestDial(t *testing.T) {
@ -518,3 +521,82 @@ func TestDialCompression(t *testing.T) {
defer ws.Close() defer ws.Close()
sendRecv(t, ws) sendRecv(t, ws)
} }
func TestSocksProxyDial(t *testing.T) {
s := newServer(t)
defer s.Close()
proxyListener, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Fatalf("listen failed: %v", err)
}
defer proxyListener.Close()
go func() {
c1, err := proxyListener.Accept()
if err != nil {
t.Errorf("proxy accept failed: %v", err)
return
}
defer c1.Close()
c1.SetDeadline(time.Now().Add(30 * time.Second))
buf := make([]byte, 32)
if _, err := io.ReadFull(c1, buf[:3]); err != nil {
t.Errorf("read failed: %v", err)
return
}
if want := []byte{5, 1, 0}; !bytes.Equal(want, buf[:len(want)]) {
t.Errorf("read %x, want %x", buf[:len(want)], want)
}
if _, err := c1.Write([]byte{5, 0}); err != nil {
t.Errorf("write failed: %v", err)
return
}
if _, err := io.ReadFull(c1, buf[:10]); err != nil {
t.Errorf("read failed: %v", err)
return
}
if want := []byte{5, 1, 0, 1}; !bytes.Equal(want, buf[:len(want)]) {
t.Errorf("read %x, want %x", buf[:len(want)], want)
return
}
buf[1] = 0
if _, err := c1.Write(buf[:10]); err != nil {
t.Errorf("write failed: %v", err)
return
}
ip := net.IP(buf[4:8])
port := binary.BigEndian.Uint16(buf[8:10])
c2, err := net.DialTCP("tcp", nil, &net.TCPAddr{IP: ip, Port: int(port)})
if err != nil {
t.Errorf("dial failed; %v", err)
return
}
defer c2.Close()
done := make(chan struct{})
go func() {
io.Copy(c1, c2)
close(done)
}()
io.Copy(c2, c1)
<-done
}()
purl, err := url.Parse("socks5://" + proxyListener.Addr().String())
if err != nil {
t.Fatalf("parse failed: %v", err)
}
cstDialer := cstDialer // make local copy for modification on next line.
cstDialer.Proxy = http.ProxyURL(purl)
ws, _, err := cstDialer.Dial(s.URL, nil)
if err != nil {
t.Fatalf("Dial: %v", err)
}
defer ws.Close()
sendRecv(t, ws)
}

77
proxy.go Normal file
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@ -0,0 +1,77 @@
// Copyright 2017 The Gorilla WebSocket 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 websocket
import (
"bufio"
"encoding/base64"
"errors"
"net"
"net/http"
"net/url"
"strings"
)
type netDialerFunc func(netowrk, addr string) (net.Conn, error)
func (fn netDialerFunc) Dial(network, addr string) (net.Conn, error) {
return fn(network, addr)
}
func init() {
proxy_RegisterDialerType("http", func(proxyURL *url.URL, forwardDialer proxy_Dialer) (proxy_Dialer, error) {
return &httpProxyDialer{proxyURL: proxyURL, fowardDial: forwardDialer.Dial}, nil
})
}
type httpProxyDialer struct {
proxyURL *url.URL
fowardDial func(network, addr string) (net.Conn, error)
}
func (hpd *httpProxyDialer) Dial(network string, addr string) (net.Conn, error) {
hostPort, _ := hostPortNoPort(hpd.proxyURL)
conn, err := hpd.fowardDial(network, hostPort)
if err != nil {
return nil, err
}
connectHeader := make(http.Header)
if user := hpd.proxyURL.User; user != nil {
proxyUser := user.Username()
if proxyPassword, passwordSet := user.Password(); passwordSet {
credential := base64.StdEncoding.EncodeToString([]byte(proxyUser + ":" + proxyPassword))
connectHeader.Set("Proxy-Authorization", "Basic "+credential)
}
}
connectReq := &http.Request{
Method: "CONNECT",
URL: &url.URL{Opaque: addr},
Host: addr,
Header: connectHeader,
}
if err := connectReq.Write(conn); err != nil {
conn.Close()
return nil, err
}
// Read response. It's OK to use and discard buffered reader here becaue
// the remote server does not speak until spoken to.
br := bufio.NewReader(conn)
resp, err := http.ReadResponse(br, connectReq)
if err != nil {
conn.Close()
return nil, err
}
if resp.StatusCode != 200 {
conn.Close()
f := strings.SplitN(resp.Status, " ", 2)
return nil, errors.New(f[1])
}
return conn, nil
}

473
x_net_proxy.go Normal file
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@ -0,0 +1,473 @@
// Code generated by golang.org/x/tools/cmd/bundle. DO NOT EDIT.
//go:generate bundle -o x_net_proxy.go golang.org/x/net/proxy
// Package proxy provides support for a variety of protocols to proxy network
// data.
//
package websocket
import (
"errors"
"io"
"net"
"net/url"
"os"
"strconv"
"strings"
"sync"
)
type proxy_direct struct{}
// Direct is a direct proxy: one that makes network connections directly.
var proxy_Direct = proxy_direct{}
func (proxy_direct) Dial(network, addr string) (net.Conn, error) {
return net.Dial(network, addr)
}
// A PerHost directs connections to a default Dialer unless the host name
// requested matches one of a number of exceptions.
type proxy_PerHost struct {
def, bypass proxy_Dialer
bypassNetworks []*net.IPNet
bypassIPs []net.IP
bypassZones []string
bypassHosts []string
}
// NewPerHost returns a PerHost Dialer that directs connections to either
// defaultDialer or bypass, depending on whether the connection matches one of
// the configured rules.
func proxy_NewPerHost(defaultDialer, bypass proxy_Dialer) *proxy_PerHost {
return &proxy_PerHost{
def: defaultDialer,
bypass: bypass,
}
}
// Dial connects to the address addr on the given network through either
// defaultDialer or bypass.
func (p *proxy_PerHost) Dial(network, addr string) (c net.Conn, err error) {
host, _, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
return p.dialerForRequest(host).Dial(network, addr)
}
func (p *proxy_PerHost) dialerForRequest(host string) proxy_Dialer {
if ip := net.ParseIP(host); ip != nil {
for _, net := range p.bypassNetworks {
if net.Contains(ip) {
return p.bypass
}
}
for _, bypassIP := range p.bypassIPs {
if bypassIP.Equal(ip) {
return p.bypass
}
}
return p.def
}
for _, zone := range p.bypassZones {
if strings.HasSuffix(host, zone) {
return p.bypass
}
if host == zone[1:] {
// For a zone ".example.com", we match "example.com"
// too.
return p.bypass
}
}
for _, bypassHost := range p.bypassHosts {
if bypassHost == host {
return p.bypass
}
}
return p.def
}
// AddFromString parses a string that contains comma-separated values
// specifying hosts that should use the bypass proxy. Each value is either an
// IP address, a CIDR range, a zone (*.example.com) or a host name
// (localhost). A best effort is made to parse the string and errors are
// ignored.
func (p *proxy_PerHost) AddFromString(s string) {
hosts := strings.Split(s, ",")
for _, host := range hosts {
host = strings.TrimSpace(host)
if len(host) == 0 {
continue
}
if strings.Contains(host, "/") {
// We assume that it's a CIDR address like 127.0.0.0/8
if _, net, err := net.ParseCIDR(host); err == nil {
p.AddNetwork(net)
}
continue
}
if ip := net.ParseIP(host); ip != nil {
p.AddIP(ip)
continue
}
if strings.HasPrefix(host, "*.") {
p.AddZone(host[1:])
continue
}
p.AddHost(host)
}
}
// AddIP specifies an IP address that will use the bypass proxy. Note that
// this will only take effect if a literal IP address is dialed. A connection
// to a named host will never match an IP.
func (p *proxy_PerHost) AddIP(ip net.IP) {
p.bypassIPs = append(p.bypassIPs, ip)
}
// AddNetwork specifies an IP range that will use the bypass proxy. Note that
// this will only take effect if a literal IP address is dialed. A connection
// to a named host will never match.
func (p *proxy_PerHost) AddNetwork(net *net.IPNet) {
p.bypassNetworks = append(p.bypassNetworks, net)
}
// AddZone specifies a DNS suffix that will use the bypass proxy. A zone of
// "example.com" matches "example.com" and all of its subdomains.
func (p *proxy_PerHost) AddZone(zone string) {
if strings.HasSuffix(zone, ".") {
zone = zone[:len(zone)-1]
}
if !strings.HasPrefix(zone, ".") {
zone = "." + zone
}
p.bypassZones = append(p.bypassZones, zone)
}
// AddHost specifies a host name that will use the bypass proxy.
func (p *proxy_PerHost) AddHost(host string) {
if strings.HasSuffix(host, ".") {
host = host[:len(host)-1]
}
p.bypassHosts = append(p.bypassHosts, host)
}
// A Dialer is a means to establish a connection.
type proxy_Dialer interface {
// Dial connects to the given address via the proxy.
Dial(network, addr string) (c net.Conn, err error)
}
// Auth contains authentication parameters that specific Dialers may require.
type proxy_Auth struct {
User, Password string
}
// FromEnvironment returns the dialer specified by the proxy related variables in
// the environment.
func proxy_FromEnvironment() proxy_Dialer {
allProxy := proxy_allProxyEnv.Get()
if len(allProxy) == 0 {
return proxy_Direct
}
proxyURL, err := url.Parse(allProxy)
if err != nil {
return proxy_Direct
}
proxy, err := proxy_FromURL(proxyURL, proxy_Direct)
if err != nil {
return proxy_Direct
}
noProxy := proxy_noProxyEnv.Get()
if len(noProxy) == 0 {
return proxy
}
perHost := proxy_NewPerHost(proxy, proxy_Direct)
perHost.AddFromString(noProxy)
return perHost
}
// proxySchemes is a map from URL schemes to a function that creates a Dialer
// from a URL with such a scheme.
var proxy_proxySchemes map[string]func(*url.URL, proxy_Dialer) (proxy_Dialer, error)
// RegisterDialerType takes a URL scheme and a function to generate Dialers from
// a URL with that scheme and a forwarding Dialer. Registered schemes are used
// by FromURL.
func proxy_RegisterDialerType(scheme string, f func(*url.URL, proxy_Dialer) (proxy_Dialer, error)) {
if proxy_proxySchemes == nil {
proxy_proxySchemes = make(map[string]func(*url.URL, proxy_Dialer) (proxy_Dialer, error))
}
proxy_proxySchemes[scheme] = f
}
// FromURL returns a Dialer given a URL specification and an underlying
// Dialer for it to make network requests.
func proxy_FromURL(u *url.URL, forward proxy_Dialer) (proxy_Dialer, error) {
var auth *proxy_Auth
if u.User != nil {
auth = new(proxy_Auth)
auth.User = u.User.Username()
if p, ok := u.User.Password(); ok {
auth.Password = p
}
}
switch u.Scheme {
case "socks5":
return proxy_SOCKS5("tcp", u.Host, auth, forward)
}
// If the scheme doesn't match any of the built-in schemes, see if it
// was registered by another package.
if proxy_proxySchemes != nil {
if f, ok := proxy_proxySchemes[u.Scheme]; ok {
return f(u, forward)
}
}
return nil, errors.New("proxy: unknown scheme: " + u.Scheme)
}
var (
proxy_allProxyEnv = &proxy_envOnce{
names: []string{"ALL_PROXY", "all_proxy"},
}
proxy_noProxyEnv = &proxy_envOnce{
names: []string{"NO_PROXY", "no_proxy"},
}
)
// envOnce looks up an environment variable (optionally by multiple
// names) once. It mitigates expensive lookups on some platforms
// (e.g. Windows).
// (Borrowed from net/http/transport.go)
type proxy_envOnce struct {
names []string
once sync.Once
val string
}
func (e *proxy_envOnce) Get() string {
e.once.Do(e.init)
return e.val
}
func (e *proxy_envOnce) init() {
for _, n := range e.names {
e.val = os.Getenv(n)
if e.val != "" {
return
}
}
}
// SOCKS5 returns a Dialer that makes SOCKSv5 connections to the given address
// with an optional username and password. See RFC 1928 and RFC 1929.
func proxy_SOCKS5(network, addr string, auth *proxy_Auth, forward proxy_Dialer) (proxy_Dialer, error) {
s := &proxy_socks5{
network: network,
addr: addr,
forward: forward,
}
if auth != nil {
s.user = auth.User
s.password = auth.Password
}
return s, nil
}
type proxy_socks5 struct {
user, password string
network, addr string
forward proxy_Dialer
}
const proxy_socks5Version = 5
const (
proxy_socks5AuthNone = 0
proxy_socks5AuthPassword = 2
)
const proxy_socks5Connect = 1
const (
proxy_socks5IP4 = 1
proxy_socks5Domain = 3
proxy_socks5IP6 = 4
)
var proxy_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 given network via the SOCKS5 proxy.
func (s *proxy_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 *proxy_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, proxy_socks5Version)
if len(s.user) > 0 && len(s.user) < 256 && len(s.password) < 256 {
buf = append(buf, 2 /* num auth methods */, proxy_socks5AuthNone, proxy_socks5AuthPassword)
} else {
buf = append(buf, 1 /* num auth methods */, proxy_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")
}
// See RFC 1929
if buf[1] == proxy_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, proxy_socks5Version, proxy_socks5Connect, 0 /* reserved */)
if ip := net.ParseIP(host); ip != nil {
if ip4 := ip.To4(); ip4 != nil {
buf = append(buf, proxy_socks5IP4)
ip = ip4
} else {
buf = append(buf, proxy_socks5IP6)
}
buf = append(buf, ip...)
} else {
if len(host) > 255 {
return errors.New("proxy: destination host name too long: " + host)
}
buf = append(buf, proxy_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(proxy_socks5Errors) {
failure = proxy_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 proxy_socks5IP4:
bytesToDiscard = net.IPv4len
case proxy_socks5IP6:
bytesToDiscard = net.IPv6len
case proxy_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
}