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socks5.go
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socks5.go
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package proxy
import (
"encoding/binary"
"errors"
"github.com/cnlh/nps/lib/common"
"github.com/cnlh/nps/lib/conn"
"github.com/cnlh/nps/lib/file"
"github.com/cnlh/nps/vender/github.com/astaxie/beego/logs"
"io"
"net"
"strconv"
)
const (
ipV4 = 1
domainName = 3
ipV6 = 4
connectMethod = 1
bindMethod = 2
associateMethod = 3
// The maximum packet size of any udp Associate packet, based on ethernet's max size,
// minus the IP and UDP headers. IPv4 has a 20 byte header, UDP adds an
// additional 4 bytes. This is a total overhead of 24 bytes. Ethernet's
// max packet size is 1500 bytes, 1500 - 24 = 1476.
maxUDPPacketSize = 1476
)
const (
succeeded uint8 = iota
serverFailure
notAllowed
networkUnreachable
hostUnreachable
connectionRefused
ttlExpired
commandNotSupported
addrTypeNotSupported
)
const (
UserPassAuth = uint8(2)
userAuthVersion = uint8(1)
authSuccess = uint8(0)
authFailure = uint8(1)
)
type Sock5ModeServer struct {
BaseServer
listener net.Listener
}
//req
func (s *Sock5ModeServer) handleRequest(c net.Conn) {
/*
The SOCKS request is formed as follows:
+----+-----+-------+------+----------+----------+
|VER | CMD | RSV | ATYP | DST.ADDR | DST.PORT |
+----+-----+-------+------+----------+----------+
| 1 | 1 | X'00' | 1 | Variable | 2 |
+----+-----+-------+------+----------+----------+
*/
header := make([]byte, 3)
_, err := io.ReadFull(c, header)
if err != nil {
logs.Warn("illegal request", err)
c.Close()
return
}
switch header[1] {
case connectMethod:
s.handleConnect(c)
case bindMethod:
s.handleBind(c)
case associateMethod:
s.handleUDP(c)
default:
s.sendReply(c, commandNotSupported)
c.Close()
}
}
//reply
func (s *Sock5ModeServer) sendReply(c net.Conn, rep uint8) {
reply := []byte{
5,
rep,
0,
1,
}
localAddr := c.LocalAddr().String()
localHost, localPort, _ := net.SplitHostPort(localAddr)
ipBytes := net.ParseIP(localHost).To4()
nPort, _ := strconv.Atoi(localPort)
reply = append(reply, ipBytes...)
portBytes := make([]byte, 2)
binary.BigEndian.PutUint16(portBytes, uint16(nPort))
reply = append(reply, portBytes...)
c.Write(reply)
}
//do conn
func (s *Sock5ModeServer) doConnect(c net.Conn, command uint8) {
addrType := make([]byte, 1)
c.Read(addrType)
var host string
switch addrType[0] {
case ipV4:
ipv4 := make(net.IP, net.IPv4len)
c.Read(ipv4)
host = ipv4.String()
case ipV6:
ipv6 := make(net.IP, net.IPv6len)
c.Read(ipv6)
host = ipv6.String()
case domainName:
var domainLen uint8
binary.Read(c, binary.BigEndian, &domainLen)
domain := make([]byte, domainLen)
c.Read(domain)
host = string(domain)
default:
s.sendReply(c, addrTypeNotSupported)
return
}
var port uint16
binary.Read(c, binary.BigEndian, &port)
// connect to host
addr := net.JoinHostPort(host, strconv.Itoa(int(port)))
var ltype string
if command == associateMethod {
ltype = common.CONN_UDP
} else {
ltype = common.CONN_TCP
}
s.DealClient(conn.NewConn(c), s.task.Client, addr, nil, ltype, func() {
s.sendReply(c, succeeded)
}, s.task.Flow, s.task.Target.LocalProxy)
return
}
//conn
func (s *Sock5ModeServer) handleConnect(c net.Conn) {
s.doConnect(c, connectMethod)
}
// passive mode
func (s *Sock5ModeServer) handleBind(c net.Conn) {
}
//udp
func (s *Sock5ModeServer) handleUDP(c net.Conn) {
/*
+----+------+------+----------+----------+----------+
|RSV | FRAG | ATYP | DST.ADDR | DST.PORT | DATA |
+----+------+------+----------+----------+----------+
| 2 | 1 | 1 | Variable | 2 | Variable |
+----+------+------+----------+----------+----------+
*/
buf := make([]byte, 3)
c.Read(buf)
// relay udp datagram silently, without any notification to the requesting client
if buf[2] != 0 {
// does not support fragmentation, drop it
logs.Warn("does not support fragmentation, drop")
dummy := make([]byte, maxUDPPacketSize)
c.Read(dummy)
}
s.doConnect(c, associateMethod)
}
//new conn
func (s *Sock5ModeServer) handleConn(c net.Conn) {
buf := make([]byte, 2)
if _, err := io.ReadFull(c, buf); err != nil {
logs.Warn("negotiation err", err)
c.Close()
return
}
if version := buf[0]; version != 5 {
logs.Warn("only support socks5, request from: ", c.RemoteAddr())
c.Close()
return
}
nMethods := buf[1]
methods := make([]byte, nMethods)
if len, err := c.Read(methods); len != int(nMethods) || err != nil {
logs.Warn("wrong method")
c.Close()
return
}
if s.task.Client.Cnf.U != "" && s.task.Client.Cnf.P != "" {
buf[1] = UserPassAuth
c.Write(buf)
if err := s.Auth(c); err != nil {
c.Close()
logs.Warn("Validation failed:", err)
return
}
} else {
buf[1] = 0
c.Write(buf)
}
s.handleRequest(c)
}
//socks5 auth
func (s *Sock5ModeServer) Auth(c net.Conn) error {
header := []byte{0, 0}
if _, err := io.ReadAtLeast(c, header, 2); err != nil {
return err
}
if header[0] != userAuthVersion {
return errors.New("验证方式不被支持")
}
userLen := int(header[1])
user := make([]byte, userLen)
if _, err := io.ReadAtLeast(c, user, userLen); err != nil {
return err
}
if _, err := c.Read(header[:1]); err != nil {
return errors.New("密码长度获取错误")
}
passLen := int(header[0])
pass := make([]byte, passLen)
if _, err := io.ReadAtLeast(c, pass, passLen); err != nil {
return err
}
if string(user) == s.task.Client.Cnf.U && string(pass) == s.task.Client.Cnf.P {
if _, err := c.Write([]byte{userAuthVersion, authSuccess}); err != nil {
return err
}
return nil
} else {
if _, err := c.Write([]byte{userAuthVersion, authFailure}); err != nil {
return err
}
return errors.New("验证不通过")
}
}
//start
func (s *Sock5ModeServer) Start() error {
return conn.NewTcpListenerAndProcess(s.task.ServerIp+":"+strconv.Itoa(s.task.Port), func(c net.Conn) {
if err := s.CheckFlowAndConnNum(s.task.Client); err != nil {
logs.Warn("client id %d, task id %d, error %s, when socks5 connection", s.task.Client.Id, s.task.Id, err.Error())
c.Close()
return
}
logs.Trace("New socks5 connection,client %d,remote address %s", s.task.Client.Id, c.RemoteAddr())
s.handleConn(c)
s.task.Client.AddConn()
}, &s.listener)
}
//new
func NewSock5ModeServer(bridge NetBridge, task *file.Tunnel) *Sock5ModeServer {
s := new(Sock5ModeServer)
s.bridge = bridge
s.task = task
return s
}
//close
func (s *Sock5ModeServer) Close() error {
return s.listener.Close()
}