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Copy pathsocks.go
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socks.go
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package gost
import (
"bytes"
"crypto/tls"
"errors"
"fmt"
"net"
"net/url"
"strconv"
"time"
"io"
"github.com/ginuerzh/gosocks4"
"github.com/ginuerzh/gosocks5"
"github.com/go-log/log"
)
const (
// MethodTLS is an extended SOCKS5 method for TLS.
MethodTLS uint8 = 0x80
// MethodTLSAuth is an extended SOCKS5 method for TLS+AUTH.
MethodTLSAuth uint8 = 0x82
)
const (
// CmdUDPTun is an extended SOCKS5 method for UDP over TCP.
CmdUDPTun uint8 = 0xF3
)
type clientSelector struct {
methods []uint8
User *url.Userinfo
TLSConfig *tls.Config
}
func (selector *clientSelector) Methods() []uint8 {
return selector.methods
}
func (selector *clientSelector) AddMethod(methods ...uint8) {
selector.methods = append(selector.methods, methods...)
}
func (selector *clientSelector) Select(methods ...uint8) (method uint8) {
return
}
func (selector *clientSelector) OnSelected(method uint8, conn net.Conn) (net.Conn, error) {
switch method {
case MethodTLS:
conn = tls.Client(conn, selector.TLSConfig)
case gosocks5.MethodUserPass, MethodTLSAuth:
if method == MethodTLSAuth {
conn = tls.Client(conn, selector.TLSConfig)
}
var username, password string
if selector.User != nil {
username = selector.User.Username()
password, _ = selector.User.Password()
}
req := gosocks5.NewUserPassRequest(gosocks5.UserPassVer, username, password)
if err := req.Write(conn); err != nil {
log.Log("[socks5]", err)
return nil, err
}
if Debug {
log.Log("[socks5]", req)
}
resp, err := gosocks5.ReadUserPassResponse(conn)
if err != nil {
log.Log("[socks5]", err)
return nil, err
}
if Debug {
log.Log("[socks5]", resp)
}
if resp.Status != gosocks5.Succeeded {
return nil, gosocks5.ErrAuthFailure
}
case gosocks5.MethodNoAcceptable:
return nil, gosocks5.ErrBadMethod
}
return conn, nil
}
type serverSelector struct {
methods []uint8
Users []*url.Userinfo
TLSConfig *tls.Config
}
func (selector *serverSelector) Methods() []uint8 {
return selector.methods
}
func (selector *serverSelector) AddMethod(methods ...uint8) {
selector.methods = append(selector.methods, methods...)
}
func (selector *serverSelector) Select(methods ...uint8) (method uint8) {
if Debug {
log.Logf("[socks5] %d %d %v", gosocks5.Ver5, len(methods), methods)
}
method = gosocks5.MethodNoAuth
for _, m := range methods {
if m == MethodTLS {
method = m
break
}
}
// when user/pass is set, auth is mandatory
if len(selector.Users) > 0 {
if method == gosocks5.MethodNoAuth {
method = gosocks5.MethodUserPass
}
if method == MethodTLS {
method = MethodTLSAuth
}
}
return
}
func (selector *serverSelector) OnSelected(method uint8, conn net.Conn) (net.Conn, error) {
if Debug {
log.Logf("[socks5] %d %d", gosocks5.Ver5, method)
}
switch method {
case MethodTLS:
conn = tls.Server(conn, selector.TLSConfig)
case gosocks5.MethodUserPass, MethodTLSAuth:
if method == MethodTLSAuth {
conn = tls.Server(conn, selector.TLSConfig)
}
req, err := gosocks5.ReadUserPassRequest(conn)
if err != nil {
log.Log("[socks5]", err)
return nil, err
}
if Debug {
log.Log("[socks5]", req.String())
}
valid := false
for _, user := range selector.Users {
username := user.Username()
password, _ := user.Password()
if (req.Username == username && req.Password == password) ||
(req.Username == username && password == "") ||
(username == "" && req.Password == password) {
valid = true
break
}
}
if len(selector.Users) > 0 && !valid {
resp := gosocks5.NewUserPassResponse(gosocks5.UserPassVer, gosocks5.Failure)
if err := resp.Write(conn); err != nil {
log.Log("[socks5]", err)
return nil, err
}
if Debug {
log.Log("[socks5]", resp)
}
log.Log("[socks5] proxy authentication required")
return nil, gosocks5.ErrAuthFailure
}
resp := gosocks5.NewUserPassResponse(gosocks5.UserPassVer, gosocks5.Succeeded)
if err := resp.Write(conn); err != nil {
log.Log("[socks5]", err)
return nil, err
}
if Debug {
log.Log("[socks5]", resp)
}
case gosocks5.MethodNoAcceptable:
return nil, gosocks5.ErrBadMethod
}
return conn, nil
}
type socks5Connector struct {
User *url.Userinfo
}
// SOCKS5Connector creates a connector for SOCKS5 proxy client.
// It accepts an optional auth info for SOCKS5 Username/Password Authentication.
func SOCKS5Connector(user *url.Userinfo) Connector {
return &socks5Connector{User: user}
}
func (c *socks5Connector) Connect(conn net.Conn, addr string) (net.Conn, error) {
selector := &clientSelector{
TLSConfig: &tls.Config{InsecureSkipVerify: true},
User: c.User,
}
selector.AddMethod(
gosocks5.MethodNoAuth,
gosocks5.MethodUserPass,
MethodTLS,
)
cc := gosocks5.ClientConn(conn, selector)
if err := cc.Handleshake(); err != nil {
return nil, err
}
conn = cc
host, port, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
p, _ := strconv.Atoi(port)
req := gosocks5.NewRequest(gosocks5.CmdConnect, &gosocks5.Addr{
Type: gosocks5.AddrDomain,
Host: host,
Port: uint16(p),
})
if err := req.Write(conn); err != nil {
return nil, err
}
if Debug {
log.Log("[socks5]", req)
}
reply, err := gosocks5.ReadReply(conn)
if err != nil {
return nil, err
}
if Debug {
log.Log("[socks5]", reply)
}
if reply.Rep != gosocks5.Succeeded {
return nil, errors.New("Service unavailable")
}
return conn, nil
}
type socks4Connector struct{}
// SOCKS4Connector creates a Connector for SOCKS4 proxy client.
func SOCKS4Connector() Connector {
return &socks4Connector{}
}
func (c *socks4Connector) Connect(conn net.Conn, addr string) (net.Conn, error) {
taddr, err := net.ResolveTCPAddr("tcp4", addr)
if err != nil {
return nil, err
}
req := gosocks4.NewRequest(gosocks4.CmdConnect,
&gosocks4.Addr{
Type: gosocks4.AddrIPv4,
Host: taddr.IP.String(),
Port: uint16(taddr.Port),
}, nil,
)
if err := req.Write(conn); err != nil {
return nil, err
}
if Debug {
log.Logf("[socks4] %s", req)
}
reply, err := gosocks4.ReadReply(conn)
if err != nil {
return nil, err
}
if Debug {
log.Logf("[socks4] %s", reply)
}
if reply.Code != gosocks4.Granted {
return nil, fmt.Errorf("[socks4] %d", reply.Code)
}
return conn, nil
}
type socks4aConnector struct{}
// SOCKS4AConnector creates a Connector for SOCKS4A proxy client.
func SOCKS4AConnector() Connector {
return &socks4aConnector{}
}
func (c *socks4aConnector) Connect(conn net.Conn, addr string) (net.Conn, error) {
host, port, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
p, _ := strconv.Atoi(port)
req := gosocks4.NewRequest(gosocks4.CmdConnect,
&gosocks4.Addr{Type: gosocks4.AddrDomain, Host: host, Port: uint16(p)}, nil)
if err := req.Write(conn); err != nil {
return nil, err
}
if Debug {
log.Logf("[socks4] %s", req)
}
reply, err := gosocks4.ReadReply(conn)
if err != nil {
return nil, err
}
if Debug {
log.Logf("[socks4] %s", reply)
}
if reply.Code != gosocks4.Granted {
return nil, fmt.Errorf("[socks4] %d", reply.Code)
}
return conn, nil
}
type socks5Handler struct {
selector *serverSelector
options *HandlerOptions
}
// SOCKS5Handler creates a server Handler for SOCKS5 proxy server.
func SOCKS5Handler(opts ...HandlerOption) Handler {
options := &HandlerOptions{}
for _, opt := range opts {
opt(options)
}
tlsConfig := options.TLSConfig
if tlsConfig == nil {
tlsConfig = DefaultTLSConfig
}
selector := &serverSelector{ // socks5 server selector
Users: options.Users,
TLSConfig: tlsConfig,
}
// methods that socks5 server supported
selector.AddMethod(
gosocks5.MethodNoAuth,
gosocks5.MethodUserPass,
MethodTLS,
MethodTLSAuth,
)
return &socks5Handler{
options: options,
selector: selector,
}
}
func (h *socks5Handler) Handle(conn net.Conn) {
defer conn.Close()
conn = gosocks5.ServerConn(conn, h.selector)
req, err := gosocks5.ReadRequest(conn)
if err != nil {
log.Log("[socks5]", err)
return
}
if Debug {
log.Logf("[socks5] %s - %s\n%s", conn.RemoteAddr(), req.Addr, req)
}
switch req.Cmd {
case gosocks5.CmdConnect:
h.handleConnect(conn, req)
case gosocks5.CmdBind:
h.handleBind(conn, req)
case gosocks5.CmdUdp:
h.handleUDPRelay(conn, req)
case CmdUDPTun:
h.handleUDPTunnel(conn, req)
default:
log.Log("[socks5] Unrecognized request:", req.Cmd)
}
}
func (h *socks5Handler) handleConnect(conn net.Conn, req *gosocks5.Request) {
addr := req.Addr.String()
if !Can("tcp", addr, h.options.Whitelist, h.options.Blacklist) {
log.Logf("[socks5-connect] Unauthorized to tcp connect to %s", addr)
rep := gosocks5.NewReply(gosocks5.NotAllowed, nil)
rep.Write(conn)
if Debug {
log.Logf("[socks5-connect] %s <- %s\n%s", conn.RemoteAddr(), req.Addr, rep)
}
return
}
cc, err := h.options.Chain.Dial(addr)
if err != nil {
log.Logf("[socks5-connect] %s -> %s : %s", conn.RemoteAddr(), req.Addr, err)
rep := gosocks5.NewReply(gosocks5.HostUnreachable, nil)
rep.Write(conn)
if Debug {
log.Logf("[socks5-connect] %s <- %s\n%s", conn.RemoteAddr(), req.Addr, rep)
}
return
}
defer cc.Close()
rep := gosocks5.NewReply(gosocks5.Succeeded, nil)
if err := rep.Write(conn); err != nil {
log.Logf("[socks5-connect] %s <- %s : %s", conn.RemoteAddr(), req.Addr, err)
return
}
if Debug {
log.Logf("[socks5-connect] %s <- %s\n%s", conn.RemoteAddr(), req.Addr, rep)
}
log.Logf("[socks5-connect] %s <-> %s", conn.RemoteAddr(), req.Addr)
transport(conn, cc)
log.Logf("[socks5-connect] %s >-< %s", conn.RemoteAddr(), req.Addr)
}
func (h *socks5Handler) handleBind(conn net.Conn, req *gosocks5.Request) {
if h.options.Chain.IsEmpty() {
addr := req.Addr.String()
if !Can("rtcp", addr, h.options.Whitelist, h.options.Blacklist) {
log.Logf("Unauthorized to tcp bind to %s", addr)
return
}
h.bindOn(conn, addr)
return
}
cc, err := h.options.Chain.Conn()
if err != nil {
log.Logf("[socks5-bind] %s <- %s : %s", conn.RemoteAddr(), req.Addr, err)
reply := gosocks5.NewReply(gosocks5.Failure, nil)
reply.Write(conn)
if Debug {
log.Logf("[socks5-bind] %s <- %s\n%s", conn.RemoteAddr(), req.Addr, reply)
}
return
}
// forward request
// note: this type of request forwarding is defined when starting server,
// so we don't need to authenticate it, as it's as explicit as whitelisting
defer cc.Close()
req.Write(cc)
log.Logf("[socks5-bind] %s <-> %s", conn.RemoteAddr(), cc.RemoteAddr())
transport(conn, cc)
log.Logf("[socks5-bind] %s >-< %s", conn.RemoteAddr(), cc.RemoteAddr())
}
func (h *socks5Handler) bindOn(conn net.Conn, addr string) {
bindAddr, _ := net.ResolveTCPAddr("tcp", addr)
ln, err := net.ListenTCP("tcp", bindAddr) // strict mode: if the port already in use, it will return error
if err != nil {
log.Logf("[socks5-bind] %s -> %s : %s", conn.RemoteAddr(), addr, err)
gosocks5.NewReply(gosocks5.Failure, nil).Write(conn)
return
}
socksAddr := toSocksAddr(ln.Addr())
// Issue: may not reachable when host has multi-interface
socksAddr.Host, _, _ = net.SplitHostPort(conn.LocalAddr().String())
reply := gosocks5.NewReply(gosocks5.Succeeded, socksAddr)
if err := reply.Write(conn); err != nil {
log.Logf("[socks5-bind] %s <- %s : %s", conn.RemoteAddr(), addr, err)
ln.Close()
return
}
if Debug {
log.Logf("[socks5-bind] %s <- %s\n%s", conn.RemoteAddr(), addr, reply)
}
log.Logf("[socks5-bind] %s - %s BIND ON %s OK", conn.RemoteAddr(), addr, socksAddr)
var pconn net.Conn
accept := func() <-chan error {
errc := make(chan error, 1)
go func() {
defer close(errc)
defer ln.Close()
c, err := ln.AcceptTCP()
if err != nil {
errc <- err
return
}
pconn = c
}()
return errc
}
pc1, pc2 := net.Pipe()
pipe := func() <-chan error {
errc := make(chan error, 1)
go func() {
defer close(errc)
defer pc1.Close()
errc <- transport(conn, pc1)
}()
return errc
}
defer pc2.Close()
for {
select {
case err := <-accept():
if err != nil || pconn == nil {
log.Logf("[socks5-bind] %s <- %s : %v", conn.RemoteAddr(), addr, err)
return
}
defer pconn.Close()
reply := gosocks5.NewReply(gosocks5.Succeeded, toSocksAddr(pconn.RemoteAddr()))
if err := reply.Write(pc2); err != nil {
log.Logf("[socks5-bind] %s <- %s : %v", conn.RemoteAddr(), addr, err)
}
if Debug {
log.Logf("[socks5-bind] %s <- %s\n%s", conn.RemoteAddr(), addr, reply)
}
log.Logf("[socks5-bind] %s <- %s PEER %s ACCEPTED", conn.RemoteAddr(), socksAddr, pconn.RemoteAddr())
log.Logf("[socks5-bind] %s <-> %s", conn.RemoteAddr(), pconn.RemoteAddr())
if err = transport(pc2, pconn); err != nil {
log.Logf("[socks5-bind] %s - %s : %v", conn.RemoteAddr(), pconn.RemoteAddr(), err)
}
log.Logf("[socks5-bind] %s >-< %s", conn.RemoteAddr(), pconn.RemoteAddr())
return
case err := <-pipe():
if err != nil {
log.Logf("[socks5-bind] %s -> %s : %v", conn.RemoteAddr(), addr, err)
}
ln.Close()
return
}
}
}
func (h *socks5Handler) handleUDPRelay(conn net.Conn, req *gosocks5.Request) {
addr := req.Addr.String()
if !Can("udp", addr, h.options.Whitelist, h.options.Blacklist) {
log.Logf("[socks5-udp] Unauthorized to udp connect to %s", addr)
rep := gosocks5.NewReply(gosocks5.NotAllowed, nil)
rep.Write(conn)
if Debug {
log.Logf("[socks5-udp] %s <- %s\n%s", conn.RemoteAddr(), req.Addr, rep)
}
return
}
relay, err := net.ListenUDP("udp", nil)
if err != nil {
log.Logf("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), relay.LocalAddr(), err)
reply := gosocks5.NewReply(gosocks5.Failure, nil)
reply.Write(conn)
if Debug {
log.Logf("[socks5-udp] %s <- %s\n%s", conn.RemoteAddr(), relay.LocalAddr(), reply)
}
return
}
defer relay.Close()
socksAddr := toSocksAddr(relay.LocalAddr())
socksAddr.Host, _, _ = net.SplitHostPort(conn.LocalAddr().String()) // replace the IP to the out-going interface's
reply := gosocks5.NewReply(gosocks5.Succeeded, socksAddr)
if err := reply.Write(conn); err != nil {
log.Logf("[socks5-udp] %s <- %s : %s", conn.RemoteAddr(), relay.LocalAddr(), err)
return
}
if Debug {
log.Logf("[socks5-udp] %s <- %s\n%s", conn.RemoteAddr(), reply.Addr, reply)
}
log.Logf("[socks5-udp] %s - %s BIND ON %s OK", conn.RemoteAddr(), relay.LocalAddr(), socksAddr)
// serve as standard socks5 udp relay local <-> remote
if h.options.Chain.IsEmpty() {
peer, er := net.ListenUDP("udp", nil)
if er != nil {
log.Logf("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), socksAddr, er)
return
}
defer peer.Close()
go h.transportUDP(relay, peer)
log.Logf("[socks5-udp] %s <-> %s", conn.RemoteAddr(), socksAddr)
if err := h.discardClientData(conn); err != nil {
log.Logf("[socks5-udp] %s - %s : %s", conn.RemoteAddr(), socksAddr, err)
}
log.Logf("[socks5-udp] %s >-< %s", conn.RemoteAddr(), socksAddr)
return
}
cc, err := h.options.Chain.Conn()
// connection error
if err != nil {
log.Logf("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), socksAddr, err)
return
}
// forward udp local <-> tunnel
defer cc.Close()
cc, err = socks5Handshake(cc, h.options.Chain.LastNode().User)
if err != nil {
log.Logf("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), socksAddr, err)
return
}
cc.SetWriteDeadline(time.Now().Add(WriteTimeout))
r := gosocks5.NewRequest(CmdUDPTun, nil)
if err := r.Write(cc); err != nil {
log.Logf("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), cc.RemoteAddr(), err)
return
}
cc.SetWriteDeadline(time.Time{})
if Debug {
log.Logf("[socks5-udp] %s -> %s\n%s", conn.RemoteAddr(), cc.RemoteAddr(), r)
}
cc.SetReadDeadline(time.Now().Add(ReadTimeout))
reply, err = gosocks5.ReadReply(cc)
if err != nil {
log.Logf("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), cc.RemoteAddr(), err)
return
}
if Debug {
log.Logf("[socks5-udp] %s <- %s\n%s", conn.RemoteAddr(), cc.RemoteAddr(), reply)
}
if reply.Rep != gosocks5.Succeeded {
log.Logf("[socks5-udp] %s <- %s : udp associate failed", conn.RemoteAddr(), cc.RemoteAddr())
return
}
cc.SetReadDeadline(time.Time{})
log.Logf("[socks5-udp] %s <-> %s [tun: %s]", conn.RemoteAddr(), socksAddr, reply.Addr)
go h.tunnelClientUDP(relay, cc)
log.Logf("[socks5-udp] %s <-> %s", conn.RemoteAddr(), socksAddr)
if err := h.discardClientData(conn); err != nil {
log.Logf("[socks5-udp] %s - %s : %s", conn.RemoteAddr(), socksAddr, err)
}
log.Logf("[socks5-udp] %s >-< %s", conn.RemoteAddr(), socksAddr)
}
func (h *socks5Handler) discardClientData(conn net.Conn) (err error) {
b := make([]byte, tinyBufferSize)
n := 0
for {
n, err = conn.Read(b) // discard any data from tcp connection
if err != nil {
if err == io.EOF { // disconnect normally
err = nil
}
break // client disconnected
}
log.Logf("[socks5-udp] read %d UNEXPECTED TCP data from client", n)
}
return
}
func (h *socks5Handler) transportUDP(relay, peer *net.UDPConn) (err error) {
errc := make(chan error, 2)
var clientAddr *net.UDPAddr
go func() {
b := make([]byte, largeBufferSize)
for {
n, laddr, err := relay.ReadFromUDP(b)
if err != nil {
errc <- err
return
}
if clientAddr == nil {
clientAddr = laddr
}
dgram, err := gosocks5.ReadUDPDatagram(bytes.NewReader(b[:n]))
if err != nil {
errc <- err
return
}
raddr, err := net.ResolveUDPAddr("udp", dgram.Header.Addr.String())
if err != nil {
continue // drop silently
}
if _, err := peer.WriteToUDP(dgram.Data, raddr); err != nil {
errc <- err
return
}
if Debug {
log.Logf("[socks5-udp] %s >>> %s length: %d", relay.LocalAddr(), raddr, len(dgram.Data))
}
}
}()
go func() {
b := make([]byte, largeBufferSize)
for {
n, raddr, err := peer.ReadFromUDP(b)
if err != nil {
errc <- err
return
}
if clientAddr == nil {
continue
}
buf := bytes.Buffer{}
dgram := gosocks5.NewUDPDatagram(gosocks5.NewUDPHeader(0, 0, toSocksAddr(raddr)), b[:n])
dgram.Write(&buf)
if _, err := relay.WriteToUDP(buf.Bytes(), clientAddr); err != nil {
errc <- err
return
}
if Debug {
log.Logf("[socks5-udp] %s <<< %s length: %d", relay.LocalAddr(), raddr, len(dgram.Data))
}
}
}()
select {
case err = <-errc:
//log.Println("w exit", err)
}
return
}
func (h *socks5Handler) tunnelClientUDP(uc *net.UDPConn, cc net.Conn) (err error) {
errc := make(chan error, 2)
var clientAddr *net.UDPAddr
go func() {
b := make([]byte, mediumBufferSize)
for {
n, addr, err := uc.ReadFromUDP(b)
if err != nil {
log.Logf("[udp-tun] %s <- %s : %s", cc.RemoteAddr(), addr, err)
errc <- err
return
}
// glog.V(LDEBUG).Infof("read udp %d, % #x", n, b[:n])
// pipe from relay to tunnel
dgram, err := gosocks5.ReadUDPDatagram(bytes.NewReader(b[:n]))
if err != nil {
errc <- err
return
}
if clientAddr == nil {
clientAddr = addr
}
dgram.Header.Rsv = uint16(len(dgram.Data))
if err := dgram.Write(cc); err != nil {
errc <- err
return
}
if Debug {
log.Logf("[udp-tun] %s >>> %s length: %d", uc.LocalAddr(), dgram.Header.Addr, len(dgram.Data))
}
}
}()
go func() {
for {
dgram, err := gosocks5.ReadUDPDatagram(cc)
if err != nil {
log.Logf("[udp-tun] %s -> 0 : %s", cc.RemoteAddr(), err)
errc <- err
return
}
// pipe from tunnel to relay
if clientAddr == nil {
continue
}
dgram.Header.Rsv = 0
buf := bytes.Buffer{}
dgram.Write(&buf)
if _, err := uc.WriteToUDP(buf.Bytes(), clientAddr); err != nil {
errc <- err
return
}
if Debug {
log.Logf("[udp-tun] %s <<< %s length: %d", uc.LocalAddr(), dgram.Header.Addr, len(dgram.Data))
}
}
}()
select {
case err = <-errc:
}
return
}
func (h *socks5Handler) handleUDPTunnel(conn net.Conn, req *gosocks5.Request) {
// serve tunnel udp, tunnel <-> remote, handle tunnel udp request
if h.options.Chain.IsEmpty() {
addr := req.Addr.String()
if !Can("rudp", addr, h.options.Whitelist, h.options.Blacklist) {
log.Logf("[socks5-udp] Unauthorized to udp bind to %s", addr)
return
}
bindAddr, _ := net.ResolveUDPAddr("udp", addr)
uc, err := net.ListenUDP("udp", bindAddr)
if err != nil {
log.Logf("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), req.Addr, err)
return
}
defer uc.Close()
socksAddr := toSocksAddr(uc.LocalAddr())
socksAddr.Host, _, _ = net.SplitHostPort(conn.LocalAddr().String())
reply := gosocks5.NewReply(gosocks5.Succeeded, socksAddr)
if err := reply.Write(conn); err != nil {
log.Logf("[socks5-udp] %s <- %s : %s", conn.RemoteAddr(), socksAddr, err)
return
}
if Debug {
log.Logf("[socks5-udp] %s <- %s\n%s", conn.RemoteAddr(), socksAddr, reply)
}
log.Logf("[socks5-udp] %s <-> %s", conn.RemoteAddr(), socksAddr)
h.tunnelServerUDP(conn, uc)
log.Logf("[socks5-udp] %s >-< %s", conn.RemoteAddr(), socksAddr)
return
}
cc, err := h.options.Chain.Conn()
// connection error
if err != nil {
log.Logf("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), req.Addr, err)
reply := gosocks5.NewReply(gosocks5.Failure, nil)
reply.Write(conn)
log.Logf("[socks5-udp] %s -> %s\n%s", conn.RemoteAddr(), req.Addr, reply)
return
}
defer cc.Close()
cc, err = socks5Handshake(cc, h.options.Chain.LastNode().User)
if err != nil {
log.Logf("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), req.Addr, err)
return
}
// tunnel <-> tunnel, direct forwarding
// note: this type of request forwarding is defined when starting server
// so we don't need to authenticate it, as it's as explicit as whitelisting
req.Write(cc)
log.Logf("[socks5-udp] %s <-> %s [tun]", conn.RemoteAddr(), cc.RemoteAddr())
transport(conn, cc)
log.Logf("[socks5-udp] %s >-< %s [tun]", conn.RemoteAddr(), cc.RemoteAddr())
}
func (h *socks5Handler) tunnelServerUDP(cc net.Conn, uc *net.UDPConn) (err error) {
errc := make(chan error, 2)
go func() {
b := make([]byte, mediumBufferSize)
for {
n, addr, err := uc.ReadFromUDP(b)
if err != nil {
log.Logf("[udp-tun] %s <- %s : %s", cc.RemoteAddr(), addr, err)
errc <- err
return
}
// pipe from peer to tunnel
dgram := gosocks5.NewUDPDatagram(
gosocks5.NewUDPHeader(uint16(n), 0, toSocksAddr(addr)), b[:n])
if err := dgram.Write(cc); err != nil {
log.Logf("[udp-tun] %s <- %s : %s", cc.RemoteAddr(), dgram.Header.Addr, err)
errc <- err
return
}
if Debug {
log.Logf("[udp-tun] %s <<< %s length: %d", cc.RemoteAddr(), dgram.Header.Addr, len(dgram.Data))
}
}
}()
go func() {
for {
dgram, err := gosocks5.ReadUDPDatagram(cc)
if err != nil {
log.Logf("[udp-tun] %s -> 0 : %s", cc.RemoteAddr(), err)
errc <- err
return
}
// pipe from tunnel to peer
addr, err := net.ResolveUDPAddr("udp", dgram.Header.Addr.String())
if err != nil {
continue // drop silently
}
if _, err := uc.WriteToUDP(dgram.Data, addr); err != nil {
log.Logf("[udp-tun] %s -> %s : %s", cc.RemoteAddr(), addr, err)
errc <- err
return
}
if Debug {
log.Logf("[udp-tun] %s >>> %s length: %d", cc.RemoteAddr(), addr, len(dgram.Data))
}
}
}()
select {
case err = <-errc:
}
return
}
func toSocksAddr(addr net.Addr) *gosocks5.Addr {
host := "0.0.0.0"
port := 0
if addr != nil {
h, p, _ := net.SplitHostPort(addr.String())
host = h
port, _ = strconv.Atoi(p)
}
return &gosocks5.Addr{
Type: gosocks5.AddrIPv4,
Host: host,
Port: uint16(port),
}
}
type socks4Handler struct {
options *HandlerOptions
}
// SOCKS4Handler creates a server Handler for SOCKS4(A) proxy server.
func SOCKS4Handler(opts ...HandlerOption) Handler {
options := &HandlerOptions{}
for _, opt := range opts {
opt(options)
}
return &socks4Handler{
options: options,
}
}
func (h *socks4Handler) Handle(conn net.Conn) {
defer conn.Close()
req, err := gosocks4.ReadRequest(conn)
if err != nil {
log.Log("[socks4]", err)
return
}
if Debug {
log.Logf("[socks4] %s -> %s\n%s", conn.RemoteAddr(), req.Addr, req)
}
switch req.Cmd {
case gosocks4.CmdConnect:
log.Logf("[socks4-connect] %s -> %s", conn.RemoteAddr(), req.Addr)
h.handleConnect(conn, req)
case gosocks4.CmdBind:
log.Logf("[socks4-bind] %s - %s", conn.RemoteAddr(), req.Addr)
h.handleBind(conn, req)
default:
log.Logf("[socks4] Unrecognized request: %d", req.Cmd)
}
}
func (h *socks4Handler) handleConnect(conn net.Conn, req *gosocks4.Request) {
addr := req.Addr.String()