Ejemplo n.º 1
0
func handShake(conn net.Conn) (err error) {
	const (
		idVer     = 0
		idNmethod = 1
	)
	// version identification and method selection message in theory can have
	// at most 256 methods, plus version and nmethod field in total 258 bytes
	// the current rfc defines only 3 authentication methods (plus 2 reserved),
	// so it won't be such long in practice

	buf := make([]byte, 258)

	var n int
	ss.SetReadTimeout(conn)
	// make sure we get the nmethod field
	if n, err = io.ReadAtLeast(conn, buf, idNmethod+1); err != nil {
		return
	}
	if buf[idVer] != socksVer5 {
		return errVer
	}
	nmethod := int(buf[idNmethod])
	msgLen := nmethod + 2
	if n == msgLen { // handshake done, common case
		// do nothing, jump directly to send confirmation
	} else if n < msgLen { // has more methods to read, rare case
		if _, err = io.ReadFull(conn, buf[n:msgLen]); err != nil {
			return
		}
	} else { // error, should not get extra data
		return errAuthExtraData
	}
	// send confirmation: version 5, no authentication required
	_, err = conn.Write([]byte{socksVer5, 0})
	return
}
Ejemplo n.º 2
0
func getRequest(conn net.Conn) (rawaddr []byte, host string, err error) {
	const (
		idVer   = 0
		idCmd   = 1
		idType  = 3 // address type index
		idIP0   = 4 // ip addres start index
		idDmLen = 4 // domain address length index
		idDm0   = 5 // domain address start index

		typeIPv4 = 1 // type is ipv4 address
		typeDm   = 3 // type is domain address
		typeIPv6 = 4 // type is ipv6 address

		lenIPv4   = 3 + 1 + net.IPv4len + 2 // 3(ver+cmd+rsv) + 1addrType + ipv4 + 2port
		lenIPv6   = 3 + 1 + net.IPv6len + 2 // 3(ver+cmd+rsv) + 1addrType + ipv6 + 2port
		lenDmBase = 3 + 1 + 1 + 2           // 3 + 1addrType + 1addrLen + 2port, plus addrLen
	)
	// refer to getRequest in server.go for why set buffer size to 263
	var buf []byte
	if (config.TcpFastOpen & 1) == 0 {
		buf = make([]byte, 263)
	} else { // Make the buffer bigger to receive client payload for tfo dialing if tfo configured.
		buf = make([]byte, 1000)
	}
	var n int
	ss.SetReadTimeout(conn)
	// read till we get possible domain length field
	if n, err = io.ReadAtLeast(conn, buf, idDmLen+1); err != nil {
		return
	}
	// check version and cmd
	if buf[idVer] != socksVer5 {
		err = errVer
		return
	}
	if buf[idCmd] != socksCmdConnect {
		err = errCmd
		return
	}

	reqLen := -1
	switch buf[idType] {
	case typeIPv4:
		reqLen = lenIPv4
	case typeIPv6:
		reqLen = lenIPv6
	case typeDm:
		reqLen = int(buf[idDmLen]) + lenDmBase
	default:
		err = errAddrType
		return
	}

	if n == reqLen {
		// common case, do nothing
	} else if n < reqLen { // rare case
		if _, err = io.ReadFull(conn, buf[n:reqLen]); err != nil {
			return
		}
	} else {
		err = errReqExtraData
		return
	}

	rawaddr = buf[idType:reqLen]

	if debug {
		switch buf[idType] {
		case typeIPv4:
			host = net.IP(buf[idIP0 : idIP0+net.IPv4len]).String()
		case typeIPv6:
			host = net.IP(buf[idIP0 : idIP0+net.IPv6len]).String()
		case typeDm:
			host = string(buf[idDm0 : idDm0+buf[idDmLen]])
		}
		port := binary.BigEndian.Uint16(buf[reqLen-2 : reqLen])
		host = net.JoinHostPort(host, strconv.Itoa(int(port)))
	}

	return
}
Ejemplo n.º 3
0
func handleConnection(conn net.Conn) {
	var (
		remote *ss.Conn
	)

	if debug {
		debug.Printf("socks connect from %s\n", conn.RemoteAddr().String())
	}
	closed := false
	defer func() {
		if !closed {
			conn.Close()
		}
	}()

	var err error = nil
	if err = handShake(conn); err != nil {
		log.Println("socks handshake:", err)
		return
	}
	rawaddr, addr, err := getRequest(conn)
	if err != nil {
		log.Println("error getting request:", err)
		return
	}
	// Sending connection established message immediately to client.
	// This could save some round trip time for creating socks connection with the client.
	// But if connection failed, the client will get connection reset error.
	_, err = conn.Write([]byte{0x05, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x08, 0x43})
	if err != nil {
		debug.Println("send connection confirmation:", err)
		return
	}

	debug.Println("1", ", len:", len(rawaddr), ", addr:", addr, "cap:", cap(rawaddr))
	// If tfo configured, read the client payload first
	// since most of the time the rtt between client and local
	// are much smaller than between local and server.
	// This could save one rtt from local to server
	// by sending client data to server on the first syn packet.

	if (config.TcpFastOpen & 1) != 0 {
		ss.SetReadTimeout(conn)
		n, err := conn.Read(rawaddr[len(rawaddr):cap(rawaddr)])
		if err != nil {
			log.Println("Failed read data from client:", err)
			return
		}
		rawaddr = rawaddr[:len(rawaddr)+n]
		debug.Println("2, n:", n, ", len:", len(rawaddr), ", addr:", addr, ", cap:", cap(rawaddr))
	}

	debug.Println("3", ", len:", len(rawaddr), ", addr:", addr, ", cap:", cap(rawaddr))

	remote, err = createServerConn(rawaddr, addr)

	if err != nil {
		if len(servers.srvCipher) > 1 {
			log.Println("Failed connect to all avaiable shadowsocks server")
		}
		log.Println("Failed connect to all avaiable shadowsocks server", err)
		return
	}
	defer func() {
		if !closed {
			remote.Close()
		}
	}()

	go ss.PipeThenClose(conn, remote)
	ss.PipeThenClose(remote, conn)
	closed = true
	debug.Println("closed connection to", addr)
}
Ejemplo n.º 4
0
func getRequest(conn *ss.Conn) (host string, extra []byte, err error) {
	const (
		idType  = 0 // address type index
		idIP0   = 1 // ip addres start index
		idDmLen = 1 // domain address length index
		idDm0   = 2 // domain address start index

		typeIPv4 = 1 // type is ipv4 address
		typeDm   = 3 // type is domain address
		typeIPv6 = 4 // type is ipv6 address

		lenIPv4   = 1 + net.IPv4len + 2 // 1addrType + ipv4 + 2port
		lenIPv6   = 1 + net.IPv6len + 2 // 1addrType + ipv6 + 2port
		lenDmBase = 1 + 1 + 2           // 1addrType + 1addrLen + 2port, plus addrLen
	)
	var buf []byte
	// buf size should at least have the same size with the largest possible
	// request size (when addrType is 3, domain name has at most 256 bytes)
	// 1(addrType) + 1(lenByte) + 256(max length address) + 2(port)
	if (config.TcpFastOpen & 2) == 0 {
		buf = make([]byte, 260)
	} else {
		// server side tfo is configured, read more data(less than a normal ethernet mtu).
		buf = make([]byte, 1500)
	}

	var n int
	// read till we get possible domain length field
	ss.SetReadTimeout(conn)
	if n, err = io.ReadAtLeast(conn, buf, idDmLen+1); err != nil {
		return
	}

	reqLen := -1
	switch buf[idType] {
	case typeIPv4:
		reqLen = lenIPv4
	case typeIPv6:
		reqLen = lenIPv6
	case typeDm:
		reqLen = int(buf[idDmLen]) + lenDmBase
	default:
		err = fmt.Errorf("addr type %d not supported", buf[idType])
		return
	}

	if n < reqLen { // rare case
		if _, err = io.ReadFull(conn, buf[n:reqLen]); err != nil {
			return
		}
	} else if n > reqLen {
		// it's possible to read more than just the request head
		extra = buf[reqLen:n]
	}

	// Return string for typeIP is not most efficient, but browsers (Chrome,
	// Safari, Firefox) all seems using typeDm exclusively. So this is not a
	// big problem.
	switch buf[idType] {
	case typeIPv4:
		host = net.IP(buf[idIP0 : idIP0+net.IPv4len]).String()
	case typeIPv6:
		host = net.IP(buf[idIP0 : idIP0+net.IPv6len]).String()
	case typeDm:
		host = string(buf[idDm0 : idDm0+buf[idDmLen]])
	}
	// parse port
	port := binary.BigEndian.Uint16(buf[reqLen-2 : reqLen])
	host = net.JoinHostPort(host, strconv.Itoa(int(port)))
	return
}