socks5 client server done

Signed-off-by: arraykeys@gmail.com <arraykeys@gmail.com>

README_ZH.md

@@ -599,7 +599,7 @@ server连接到bridge的时候,如果同时有多个client连接到同一个brid
 ![5.2](/docs/images/5.2.png)  
 使用本地端口8090,假设上级SOCKS5代理是`22.22.22.22:8080`  
 `./proxy socks -t tcp -p "0.0.0.0:8090" -T tcp -P "22.22.22.22:8080" `  
-我们还可以指定网站域名的黑白名单文件,一行一个域名,匹配规则是最右匹配,比如:baidu.com,匹配的是*.*.baidu.com,黑名单的域名域名直接走上级代理,白名单的域名不走上级代理.  
+我们还可以指定网站域名的黑白名单文件,一行一个域名,匹配规则是最右匹配,比如:baidu.com,匹配的是*.*.baidu.com,黑名单的域名域名直接走上级代理,白名单的域名不走上级代理;如果域名即在黑名单又在白名单中,那么黑名单起作用.  
 `./proxy socks -p "0.0.0.0:8090" -T tcp -P "22.22.22.22:8080"  -b blocked.txt -d direct.txt`  
   
 #### **5.3.SOCKS二级代理(加密)**  

utils/socks/client.go

@@ -0,0 +1,253 @@
+package socks
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"strconv"
+	"time"
+)
+
+var socks5Errors = []string{
+	"",
+	"general failure",
+	"connection forbidden",
+	"network unreachable",
+	"host unreachable",
+	"connection refused",
+	"TTL expired",
+	"command not supported",
+	"address type not supported",
+}
+
+type Auth struct {
+	User, Password string
+}
+type ClientConn struct {
+	user     string
+	password string
+	conn     *net.Conn
+	header   []byte
+	timeout  time.Duration
+	addr     string
+	network  string
+	udpAddr  string
+}
+
+// SOCKS5 returns a Dialer that makes SOCKSv5 connections to the given address
+// with an optional username and password. See RFC 1928 and RFC 1929.
+// target must be a canonical address with a host and port.
+// network : tcp udp
+func NewClientConn(conn *net.Conn, network, target string, timeout time.Duration, auth *Auth, header []byte) *ClientConn {
+	s := &ClientConn{
+		conn:    conn,
+		network: network,
+		timeout: timeout,
+	}
+	if auth != nil {
+		s.user = auth.User
+		s.password = auth.Password
+	}
+	if header != nil && len(header) > 0 {
+		s.header = header
+	}
+	if network == "udp" && target == "" {
+		target = "0.0.0.0:1"
+	}
+	s.addr = target
+	return s
+}
+
+// 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 *ClientConn) Connect() error {
+	host, portStr, err := net.SplitHostPort(s.addr)
+	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)
+	}
+
+	if err := s.handshake(host); err != nil {
+		return err
+	}
+	buf := []byte{}
+	if s.network == "tcp" {
+		buf = append(buf, VERSION_V5, CMD_CONNECT, 0 /* reserved */)
+
+	} else {
+		buf = append(buf, VERSION_V5, CMD_ASSOCIATE, 0 /* reserved */)
+	}
+	if ip := net.ParseIP(host); ip != nil {
+		if ip4 := ip.To4(); ip4 != nil {
+			buf = append(buf, ATYP_IPV4)
+			ip = ip4
+		} else {
+			buf = append(buf, ATYP_IPV6)
+		}
+		buf = append(buf, ip...)
+	} else {
+		if len(host) > 255 {
+			return errors.New("proxy: destination host name too long: " + host)
+		}
+		buf = append(buf, ATYP_DOMAIN)
+		buf = append(buf, byte(len(host)))
+		buf = append(buf, host...)
+	}
+	buf = append(buf, byte(port>>8), byte(port))
+	(*s.conn).SetDeadline(time.Now().Add(s.timeout))
+	if _, err := (*s.conn).Write(buf); err != nil {
+		return errors.New("proxy: failed to write connect request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+	(*s.conn).SetDeadline(time.Time{})
+	(*s.conn).SetDeadline(time.Now().Add(s.timeout))
+	if _, err := io.ReadFull((*s.conn), buf[:4]); err != nil {
+		return errors.New("proxy: failed to read connect reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+	(*s.conn).SetDeadline(time.Time{})
+	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 ATYP_IPV4:
+		bytesToDiscard = net.IPv4len
+	case ATYP_IPV6:
+		bytesToDiscard = net.IPv6len
+	case ATYP_DOMAIN:
+		(*s.conn).SetDeadline(time.Now().Add(s.timeout))
+		_, err := io.ReadFull((*s.conn), buf[:1])
+		(*s.conn).SetDeadline(time.Time{})
+		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]
+	}
+	(*s.conn).SetDeadline(time.Now().Add(s.timeout))
+	if _, err := io.ReadFull((*s.conn), buf); err != nil {
+		return errors.New("proxy: failed to read address from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+	(*s.conn).SetDeadline(time.Time{})
+	var ip net.IP
+	ip = buf
+	ipStr := ""
+	if bytesToDiscard == net.IPv4len || bytesToDiscard == net.IPv6len {
+		if ipv4 := ip.To4(); ipv4 != nil {
+			ipStr = ipv4.String()
+		} else {
+			ipStr = ip.To16().String()
+		}
+	}
+	//log.Printf("%v", ipStr)
+	// Also need to discard the port number
+	(*s.conn).SetDeadline(time.Now().Add(s.timeout))
+	if _, err := io.ReadFull((*s.conn), buf[:2]); err != nil {
+		return errors.New("proxy: failed to read port from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+	p := binary.BigEndian.Uint16([]byte{buf[0], buf[1]})
+	//log.Printf("%v", p)
+	s.udpAddr = net.JoinHostPort(ipStr, fmt.Sprintf("%d", p))
+	//log.Printf("%v", s.udpAddr)
+	(*s.conn).SetDeadline(time.Time{})
+	return nil
+}
+func (s *ClientConn) SendUDP(data []byte, addr string) (respData []byte, err error) {
+
+	c, err := net.DialTimeout("udp", s.udpAddr, s.timeout)
+	if err != nil {
+		return
+	}
+	conn := c.(*net.UDPConn)
+
+	p := NewPacketUDP()
+	p.Build(addr, data)
+	conn.SetDeadline(time.Now().Add(s.timeout))
+	conn.Write(p.Bytes())
+	conn.SetDeadline(time.Time{})
+
+	buf := make([]byte, 1024)
+	conn.SetDeadline(time.Now().Add(s.timeout))
+	n, _, err := conn.ReadFrom(buf)
+	conn.SetDeadline(time.Time{})
+	if err != nil {
+		return
+	}
+	respData = buf[:n]
+	return
+}
+func (s *ClientConn) handshake(host string) error {
+
+	// the size here is just an estimate
+	buf := make([]byte, 0, 6+len(host))
+
+	buf = append(buf, VERSION_V5)
+	if len(s.user) > 0 && len(s.user) < 256 && len(s.password) < 256 {
+		buf = append(buf, 2 /* num auth methods */, Method_NO_AUTH, Method_USER_PASS)
+	} else {
+		buf = append(buf, 1 /* num auth methods */, Method_NO_AUTH)
+	}
+	(*s.conn).SetDeadline(time.Now().Add(s.timeout))
+	if _, err := (*s.conn).Write(buf); err != nil {
+		return errors.New("proxy: failed to write greeting to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+	(*s.conn).SetDeadline(time.Time{})
+
+	(*s.conn).SetDeadline(time.Now().Add(s.timeout))
+	if _, err := io.ReadFull((*s.conn), buf[:2]); err != nil {
+		return errors.New("proxy: failed to read greeting from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+	}
+	(*s.conn).SetDeadline(time.Time{})
+
+	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] == Method_USER_PASS {
+		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...)
+		(*s.conn).SetDeadline(time.Now().Add(s.timeout))
+		if _, err := (*s.conn).Write(buf); err != nil {
+			return errors.New("proxy: failed to write authentication request to SOCKS5 proxy at " + s.addr + ": " + err.Error())
+		}
+		(*s.conn).SetDeadline(time.Time{})
+		(*s.conn).SetDeadline(time.Now().Add(s.timeout))
+		if _, err := io.ReadFull((*s.conn), buf[:2]); err != nil {
+			return errors.New("proxy: failed to read authentication reply from SOCKS5 proxy at " + s.addr + ": " + err.Error())
+		}
+		(*s.conn).SetDeadline(time.Time{})
+		if buf[1] != 0 {
+			return errors.New("proxy: SOCKS5 proxy at " + s.addr + " rejected username/password")
+		}
+	}
+	return nil
+}

utils/socks/server.go

@@ -0,0 +1,225 @@
+package socks
+
+import (
+	"fmt"
+	"net"
+	"snail007/proxy/utils"
+	"strings"
+	"time"
+)
+
+const (
+	Method_NO_AUTH         = uint8(0x00)
+	Method_GSSAPI          = uint8(0x01)
+	Method_USER_PASS       = uint8(0x02)
+	Method_IANA            = uint8(0x7F)
+	Method_RESVERVE        = uint8(0x80)
+	Method_NONE_ACCEPTABLE = uint8(0xFF)
+	VERSION_V5             = uint8(0x05)
+	CMD_CONNECT            = uint8(0x01)
+	CMD_BIND               = uint8(0x02)
+	CMD_ASSOCIATE          = uint8(0x03)
+	ATYP_IPV4              = uint8(0x01)
+	ATYP_DOMAIN            = uint8(0x03)
+	ATYP_IPV6              = uint8(0x04)
+	REP_SUCCESS            = uint8(0x00)
+	REP_REQ_FAIL           = uint8(0x01)
+	REP_RULE_FORBIDDEN     = uint8(0x02)
+	REP_NETWOR_UNREACHABLE = uint8(0x03)
+	REP_HOST_UNREACHABLE   = uint8(0x04)
+	REP_CONNECTION_REFUSED = uint8(0x05)
+	REP_TTL_TIMEOUT        = uint8(0x06)
+	REP_CMD_UNSUPPORTED    = uint8(0x07)
+	REP_ATYP_UNSUPPORTED   = uint8(0x08)
+	REP_UNKNOWN            = uint8(0x09)
+	RSV                    = uint8(0x00)
+)
+
+var (
+	ZERO_IP   = []byte{0x00, 0x00, 0x00, 0x00}
+	ZERO_PORT = []byte{0x00, 0x00}
+)
+
+type ServerConn struct {
+	target   string
+	user     string
+	password string
+	conn     *net.Conn
+	timeout  time.Duration
+	auth     *utils.BasicAuth
+	header   []byte
+	ver      uint8
+	//method
+	methodsCount uint8
+	methods      []uint8
+	method       uint8
+	//request
+	cmd         uint8
+	reserve     uint8
+	addressType uint8
+	dstAddr     string
+	dstPort     string
+	dstHost     string
+	udpAddress  string
+}
+
+func NewServerConn(conn *net.Conn, timeout time.Duration, auth *utils.BasicAuth, udpAddress string, header []byte) *ServerConn {
+	if udpAddress == "" {
+		udpAddress = "0.0.0.0:16666"
+	}
+	s := &ServerConn{
+		conn:       conn,
+		timeout:    timeout,
+		auth:       auth,
+		header:     header,
+		ver:        VERSION_V5,
+		udpAddress: udpAddress,
+	}
+	return s
+
+}
+func (s *ServerConn) Close() {
+	utils.CloseConn(s.conn)
+}
+func (s *ServerConn) AuthData() Auth {
+	return Auth{s.user, s.password}
+}
+func (s *ServerConn) Method() uint8 {
+	return s.method
+}
+func (s *ServerConn) Target() string {
+	return s.target
+}
+func (s *ServerConn) Handshake() (err error) {
+	remoteAddr := (*s.conn).RemoteAddr()
+	//协商开始
+	//method select request
+	var methodReq MethodsRequest
+	(*s.conn).SetReadDeadline(time.Now().Add(time.Second * s.timeout))
+
+	methodReq, e := NewMethodsRequest((*s.conn), s.header)
+	(*s.conn).SetReadDeadline(time.Time{})
+	if e != nil {
+		(*s.conn).SetReadDeadline(time.Now().Add(time.Second * s.timeout))
+		methodReq.Reply(Method_NONE_ACCEPTABLE)
+		(*s.conn).SetReadDeadline(time.Time{})
+		err = fmt.Errorf("new methods request fail,ERR: %s", e)
+		return
+	}
+	if s.auth == nil {
+		if !methodReq.Select(Method_NO_AUTH) {
+			(*s.conn).SetReadDeadline(time.Now().Add(time.Second * s.timeout))
+			methodReq.Reply(Method_NONE_ACCEPTABLE)
+			(*s.conn).SetReadDeadline(time.Time{})
+			err = fmt.Errorf("none method found : Method_NO_AUTH")
+			return
+		}
+		s.method = Method_NO_AUTH
+		//method select reply
+		(*s.conn).SetReadDeadline(time.Now().Add(time.Second * s.timeout))
+		err = methodReq.Reply(Method_NO_AUTH)
+		(*s.conn).SetReadDeadline(time.Time{})
+		if err != nil {
+			err = fmt.Errorf("reply answer data fail,ERR: %s", err)
+			return
+		}
+		// err = fmt.Errorf("% x", methodReq.Bytes())
+	} else {
+		//auth
+		if !methodReq.Select(Method_USER_PASS) {
+			(*s.conn).SetReadDeadline(time.Now().Add(time.Second * s.timeout))
+			methodReq.Reply(Method_NONE_ACCEPTABLE)
+			(*s.conn).SetReadDeadline(time.Time{})
+			err = fmt.Errorf("none method found : Method_USER_PASS")
+			return
+		}
+		s.method = Method_USER_PASS
+		//method reply need auth
+		(*s.conn).SetReadDeadline(time.Now().Add(time.Second * s.timeout))
+		err = methodReq.Reply(Method_USER_PASS)
+		(*s.conn).SetReadDeadline(time.Time{})
+		if err != nil {
+			err = fmt.Errorf("reply answer data fail,ERR: %s", err)
+			return
+		}
+		//read auth
+		buf := make([]byte, 500)
+		var n int
+		(*s.conn).SetReadDeadline(time.Now().Add(time.Second * s.timeout))
+		n, err = (*s.conn).Read(buf)
+		(*s.conn).SetReadDeadline(time.Time{})
+		if err != nil {
+			err = fmt.Errorf("read auth info fail,ERR: %s", err)
+			return
+		}
+		r := buf[:n]
+		s.user = string(r[2 : r[1]+2])
+		s.password = string(r[2+r[1]+1:])
+		//err = fmt.Errorf("user:%s,pass:%s", user, pass)
+		//auth
+		_addr := strings.Split(remoteAddr.String(), ":")
+		if s.auth.CheckUserPass(s.user, s.password, _addr[0], "") {
+			(*s.conn).SetDeadline(time.Now().Add(time.Millisecond * time.Duration(s.timeout)))
+			_, err = (*s.conn).Write([]byte{0x01, 0x00})
+			(*s.conn).SetDeadline(time.Time{})
+			if err != nil {
+				err = fmt.Errorf("answer auth success to %s fail,ERR: %s", remoteAddr, err)
+				return
+			}
+		} else {
+			(*s.conn).SetDeadline(time.Now().Add(time.Millisecond * time.Duration(s.timeout)))
+			_, err = (*s.conn).Write([]byte{0x01, 0x01})
+			(*s.conn).SetDeadline(time.Time{})
+			if err != nil {
+				err = fmt.Errorf("answer auth fail to %s fail,ERR: %s", remoteAddr, err)
+				return
+			}
+			err = fmt.Errorf("auth fail from %s", remoteAddr)
+			return
+		}
+	}
+	//request detail
+	(*s.conn).SetReadDeadline(time.Now().Add(time.Second * s.timeout))
+	request, e := NewRequest(*s.conn)
+	(*s.conn).SetReadDeadline(time.Time{})
+	if e != nil {
+		err = fmt.Errorf("read request data fail,ERR: %s", e)
+		return
+	}
+	//协商结束
+
+	switch request.CMD() {
+	case CMD_BIND:
+		err = request.TCPReply(REP_UNKNOWN)
+		if err != nil {
+			err = fmt.Errorf("TCPReply REP_UNKNOWN to %s fail,ERR: %s", remoteAddr, err)
+			return
+		}
+		err = fmt.Errorf("cmd bind not supported, form: %s", remoteAddr)
+		return
+	case CMD_CONNECT:
+		err = request.TCPReply(REP_SUCCESS)
+		if err != nil {
+			err = fmt.Errorf("TCPReply REP_SUCCESS to %s fail,ERR: %s", remoteAddr, err)
+			return
+		}
+	case CMD_ASSOCIATE:
+		err = request.UDPReply(REP_SUCCESS, s.udpAddress)
+		if err != nil {
+			err = fmt.Errorf("UDPReply REP_SUCCESS to %s fail,ERR: %s", remoteAddr, err)
+			return
+		}
+	}
+
+	//fill socks info
+	s.target = request.Addr()
+	s.methodsCount = methodReq.MethodsCount()
+	s.methods = methodReq.Methods()
+	s.cmd = request.CMD()
+	s.reserve = request.reserve
+	s.addressType = request.addressType
+	s.dstAddr = request.dstAddr
+	s.dstHost = request.dstHost
+	s.dstPort = request.dstPort
+	return
+}

utils/socks/structs.go

@@ -3,44 +3,13 @@ package socks
 import (
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"net"
 	"strconv"
 )
 
-const (
-	Method_NO_AUTH         = uint8(0x00)
-	Method_GSSAPI          = uint8(0x01)
-	Method_USER_PASS       = uint8(0x02)
-	Method_IANA            = uint8(0x7F)
-	Method_RESVERVE        = uint8(0x80)
-	Method_NONE_ACCEPTABLE = uint8(0xFF)
-	VERSION_V5             = uint8(0x05)
-	CMD_CONNECT            = uint8(0x01)
-	CMD_BIND               = uint8(0x02)
-	CMD_ASSOCIATE          = uint8(0x03)
-	ATYP_IPV4              = uint8(0x01)
-	ATYP_DOMAIN            = uint8(0x03)
-	ATYP_IPV6              = uint8(0x04)
-	REP_SUCCESS            = uint8(0x00)
-	REP_REQ_FAIL           = uint8(0x01)
-	REP_RULE_FORBIDDEN     = uint8(0x02)
-	REP_NETWOR_UNREACHABLE = uint8(0x03)
-	REP_HOST_UNREACHABLE   = uint8(0x04)
-	REP_CONNECTION_REFUSED = uint8(0x05)
-	REP_TTL_TIMEOUT        = uint8(0x06)
-	REP_CMD_UNSUPPORTED    = uint8(0x07)
-	REP_ATYP_UNSUPPORTED   = uint8(0x08)
-	REP_UNKNOWN            = uint8(0x09)
-	RSV                    = uint8(0x00)
-)
-
-var (
-	ZERO_IP   = []byte{0x00, 0x00, 0x00, 0x00}
-	ZERO_PORT = []byte{0x00, 0x00}
-)
-
 type Request struct {
 	ver         uint8
 	cmd         uint8
@@ -57,7 +26,7 @@ func NewRequest(rw io.ReadWriter, header ...[]byte) (req Request, err interface{
 	var b = make([]byte, 1024)
 	var n int
 	req = Request{rw: rw}
-	if len(header) == 1 {
+	if header != nil && len(header) == 1 && len(header[0]) > 1 {
 		b = header[0]
 		n = len(header[0])
 	} else {
@@ -71,7 +40,6 @@ func NewRequest(rw io.ReadWriter, header ...[]byte) (req Request, err interface{
 	req.cmd = uint8(b[1])
 	req.reserve = uint8(b[2])
 	req.addressType = uint8(b[3])
-
 	if b[0] != 0x5 {
 		err = fmt.Errorf("sosck version supported")
 		req.TCPReply(REP_REQ_FAIL)
@@ -129,7 +97,7 @@ func (s *Request) NewReply(rep uint8, addr string) []byte {
 		ipv6[4], ipv6[5], ipv6[6], ipv6[7],
 		ipv6[8], ipv6[9], ipv6[10], ipv6[11],
 	)
-	if ipv6 != nil && "0000000000255255" != zeroiIPv6 {
+	if ipb == nil && ipv6 != nil && "0000000000255255" != zeroiIPv6 {
 		atyp = ATYP_IPV6
 		ipb = ip.To16()
 	}
@@ -165,7 +133,7 @@ func NewMethodsRequest(r io.ReadWriter, header ...[]byte) (s MethodsRequest, err
 	s.rw = &r
 	var buf = make([]byte, 300)
 	var n int
-	if len(header) == 1 {
+	if header != nil && len(header) == 1 && len(header[0]) > 1 {
 		buf = header[0]
 		n = len(header[0])
 	} else {
@@ -182,7 +150,6 @@ func NewMethodsRequest(r io.ReadWriter, header ...[]byte) (s MethodsRequest, err
 		err = fmt.Errorf("socks methods data length error")
 		return
 	}
-
 	s.ver = buf[0]
 	s.methodsCount = buf[1]
 	s.methods = buf[2:n]
@@ -195,6 +162,9 @@ func (s *MethodsRequest) Version() uint8 {
 func (s *MethodsRequest) MethodsCount() uint8 {
 	return s.methodsCount
 }
+func (s *MethodsRequest) Methods() []uint8 {
+	return s.methods
+}
 func (s *MethodsRequest) Select(method uint8) bool {
 	for _, m := range s.methods {
 		if m == method {
@@ -211,17 +181,6 @@ func (s *MethodsRequest) Bytes() []byte {
 	return s.bytes
 }
 
-type UDPPacket struct {
-	rsv     uint16
-	frag    uint8
-	atype   uint8
-	dstHost string
-	dstPort string
-	data    []byte
-	header  []byte
-	bytes   []byte
-}
-
 func ParseUDPPacket(b []byte) (p UDPPacket, err error) {
 	p = UDPPacket{}
 	p.frag = uint8(b[2])
@@ -249,6 +208,18 @@ func ParseUDPPacket(b []byte) (p UDPPacket, err error) {
 	p.header = b[:portIndex+2]
 	return
 }
+
+type UDPPacket struct {
+	rsv     uint16
+	frag    uint8
+	atype   uint8
+	dstHost string
+	dstPort string
+	data    []byte
+	header  []byte
+	bytes   []byte
+}
+
 func (s *UDPPacket) Header() []byte {
 	return s.header
 }
@@ -268,3 +239,104 @@ func (s *UDPPacket) Port() string {
 func (s *UDPPacket) Data() []byte {
 	return s.data
 }
+
+type PacketUDP struct {
+	rsv     uint16
+	frag    uint8
+	atype   uint8
+	dstHost string
+	dstPort string
+	data    []byte
+}
+
+func NewPacketUDP() (p PacketUDP) {
+	return PacketUDP{}
+}
+func (p *PacketUDP) Build(destAddr string, data []byte) (err error) {
+	host, port, err := net.SplitHostPort(destAddr)
+	if err != nil {
+		return
+	}
+	p.rsv = 0
+	p.frag = 0
+	p.dstHost = host
+	p.dstPort = port
+	p.atype = ATYP_IPV4
+	if ip := net.ParseIP(host); ip != nil {
+		if ip4 := ip.To4(); ip4 != nil {
+			p.atype = ATYP_IPV4
+			ip = ip4
+		} else {
+			p.atype = ATYP_IPV6
+		}
+	} else {
+		if len(host) > 255 {
+			err = errors.New("proxy: destination host name too long: " + host)
+			return
+		}
+		p.atype = ATYP_DOMAIN
+	}
+	p.data = data
+
+	return
+}
+func (p *PacketUDP) Parse(b []byte) (err error) {
+	p.frag = uint8(b[2])
+	if p.frag != 0 {
+		err = fmt.Errorf("FRAG only support for 0 , %v ,%v", p.frag, b[:4])
+		return
+	}
+	portIndex := 0
+	p.atype = b[3]
+	switch p.atype {
+	case ATYP_IPV4: //IP V4
+		p.dstHost = net.IPv4(b[4], b[5], b[6], b[7]).String()
+		portIndex = 8
+	case ATYP_DOMAIN: //域名
+		domainLen := uint8(b[4])
+		p.dstHost = string(b[5 : 5+domainLen]) //b[4]表示域名的长度
+		portIndex = int(5 + domainLen)
+	case ATYP_IPV6: //IP V6
+		p.dstHost = net.IP{b[4], b[5], b[6], b[7], b[8], b[9], b[10], b[11], b[12], b[13], b[14], b[15], b[16], b[17], b[18], b[19]}.String()
+		portIndex = 20
+	}
+	p.dstPort = strconv.Itoa(int(b[portIndex])<<8 | int(b[portIndex+1]))
+	p.data = b[portIndex+2:]
+	return
+}
+func (p *PacketUDP) Header() []byte {
+	header := new(bytes.Buffer)
+	header.Write([]byte{0x00, 0x00, p.frag, p.atype})
+	if p.atype == ATYP_IPV4 {
+		ip := net.ParseIP(p.dstHost)
+		header.Write(ip.To4())
+	} else if p.atype == ATYP_IPV6 {
+		ip := net.ParseIP(p.dstHost)
+		header.Write(ip.To16())
+	} else if p.atype == ATYP_DOMAIN {
+		hBytes := []byte(p.dstHost)
+		header.WriteByte(byte(len(hBytes)))
+		header.Write(hBytes)
+	}
+	port, _ := strconv.ParseUint(p.dstPort, 10, 64)
+	portBytes := new(bytes.Buffer)
+	binary.Write(portBytes, binary.BigEndian, port)
+	header.Write(portBytes.Bytes()[portBytes.Len()-2:])
+	return header.Bytes()
+}
+func (p *PacketUDP) Bytes() []byte {
+	packBytes := new(bytes.Buffer)
+	packBytes.Write(p.Header())
+	packBytes.Write(p.data)
+	return packBytes.Bytes()
+}
+func (p *PacketUDP) Host() string {
+	return p.dstHost
+}
+
+func (p *PacketUDP) Port() string {
+	return p.dstPort
+}
+func (p *PacketUDP) Data() []byte {
+	return p.data
+}