fix(修复异常): 修复无法区分无数据和出错

probe.go

@@ -52,7 +52,7 @@ func main() {
 	var err error
 	if s5 != "" {
 		fmt.Printf("通过代理探测: %s\n", s5)
-		conn, err = DialSocks5UDP(s5)
+		conn, err = DialSocks5UDP(s5, network)
 		if err != nil {
 			fmt.Printf("连接代理失败: %v\n", err)
 			return

probe_nat.go

@@ -103,7 +103,9 @@ func performTest(conn net.PacketConn, serverAddr string, network string, timeout
 		return nil, nil, err
 	}
 	txID := [12]byte{}
-	rand.Read(txID[:])
+	if _, err := rand.Read(txID[:]); err != nil {
+		return nil, nil, err
+	}
 	req := encodeSTUNRequest(txID, changeIP, changePort)
 	if _, err := conn.WriteTo(req, dst); err != nil {
 		return nil, nil, err
@@ -147,6 +149,14 @@ func DetectNAT(conn net.PacketConn, primarySTUN, secondarySTUN, network string,
 		return res
 	}
 	res.MappedIP = mappedAddr1.String()
+	if localAddr, ok := conn.LocalAddr().(*net.UDPAddr); ok {
+		if localAddr.IP.Equal(mappedAddr1.IP) && localAddr.Port == mappedAddr1.Port {
+			res.Type = NATOpen
+			res.Mapping = MappingEndpointIndependent
+			res.Filtering = FilteringEndpointIndependent
+			return res
+		}
+	}
 	var targetSTUN2 string
 	if secondarySTUN != "" {
 		targetSTUN2 = secondarySTUN
@@ -158,7 +168,10 @@ func DetectNAT(conn net.PacketConn, primarySTUN, secondarySTUN, network string,
 			host, port, _ := net.SplitHostPort(primarySTUN)
 			ips, err := net.LookupIP(host)
 			if err == nil && len(ips) > 1 {
-				primaryIP, _ := net.ResolveIPAddr("ip", host)
+				primaryIP, err := net.ResolveIPAddr("ip", host)
+				if err != nil {
+					return res
+				}
 				wantIPv4 := network == "udp4"
 				wantIPv6 := network == "udp6"
 				if network == "udp" {

probe_socks5.go

@@ -58,7 +58,7 @@ func (c *socks5PacketConn) ReadFrom(p []byte) (n int, addr net.Addr, err error)
 		return 0, nil, err
 	}
 	if n < 10 {
-		return 0, nil, nil
+		return 0, nil, errors.New("packet too short")
 	}
 	atyp := buf[3]
 	var rAddr *net.UDPAddr
@@ -93,6 +93,8 @@ func (c *socks5PacketConn) ReadFrom(p []byte) (n int, addr net.Addr, err error)
 		port := binary.BigEndian.Uint16(buf[20:22])
 		rAddr = &net.UDPAddr{IP: ip, Port: int(port)}
 		dataOffset = 22
+	default:
+		return 0, nil, fmt.Errorf("unknown address type: 0x%x", atyp)
 	}
 	copy(p, buf[dataOffset:n])
 	return n - dataOffset, rAddr, nil
@@ -142,8 +144,12 @@ func (c *socks5PacketConn) WriteTo(p []byte, addr net.Addr) (n int, err error) {
 // Close 关闭连接
 // 返回: err 关闭错误
 func (c *socks5PacketConn) Close() error {
-	c.tcpConn.Close()
+	err1 := c.tcpConn.Close()
-	return c.udpConn.Close()
+	err2 := c.udpConn.Close()
+	if err1 != nil {
+		return err1
+	}
+	return err2
 }
 
 // LocalAddr 获取本地地址
@@ -174,9 +180,9 @@ func (c *socks5PacketConn) SetWriteDeadline(t time.Time) error {
 }
 
 // DialSocks5UDP 建立SOCKS5 UDP关联
-// 入参: proxyAddr 代理服务器地址
+// 入参: proxyAddr 代理服务器地址, network 网络协议(udp/udp4/udp6)
 // 返回: conn 数据包连接, err 连接错误
-func DialSocks5UDP(proxyAddr string) (net.PacketConn, error) {
+func DialSocks5UDP(proxyAddr, network string) (net.PacketConn, error) {
 	var host string
 	if strings.Contains(proxyAddr, "://") {
 		u, err := url.Parse(proxyAddr)
@@ -187,7 +193,14 @@ func DialSocks5UDP(proxyAddr string) (net.PacketConn, error) {
 	} else {
 		host = proxyAddr
 	}
-	conn, err := net.DialTimeout("tcp", host, 5*time.Second)
+	tcpNetwork := "tcp"
+	switch network {
+	case "udp4":
+		tcpNetwork = "tcp4"
+	case "udp6":
+		tcpNetwork = "tcp6"
+	}
+	conn, err := net.DialTimeout(tcpNetwork, host, 5*time.Second)
 	if err != nil {
 		return nil, err
 	}
@@ -266,7 +279,7 @@ func DialSocks5UDP(proxyAddr string) (net.PacketConn, error) {
 		}
 	}
 	relayAddr := &net.UDPAddr{IP: relayIP, Port: relayPort}
-	lConn, err := net.ListenUDP("udp", nil)
+	lConn, err := net.ListenUDP(network, nil)
 	if err != nil {
 		conn.Close()
 		return nil, err

probe_stun.go

@@ -136,9 +136,9 @@ func decodeSTUNResponse(data []byte, txID [12]byte) (*stunMessage, error) {
 }
 
 // parseAddress 解析STUN属性中的地址信息
-// 入参: attrType 属性类型, data 属性值数据
+// 入参: attrType 属性类型, data 属性值数据, txID 事务ID用于XOR解码
 // 返回: addr 解析出的UDP地址, err 解析错误信息
-func parseAddress(attrType uint16, data []byte) (*net.UDPAddr, error) {
+func parseAddress(attrType uint16, data []byte, txID [12]byte) (*net.UDPAddr, error) {
 	if len(data) < 4 {
 		return nil, errors.New("attribute too short")
 	}
@@ -157,12 +157,15 @@ func parseAddress(attrType uint16, data []byte) (*net.UDPAddr, error) {
 	copy(ip, data[4:4+ipLen])
 	if attrType == attrXorMappedAddress {
 		port ^= uint16(stunMagicCookie >> 16)
-		if ipLen == 4 {
 		mc := make([]byte, 4)
 		binary.BigEndian.PutUint32(mc, stunMagicCookie)
 		for i := 0; i < 4; i++ {
 			ip[i] ^= mc[i]
 		}
+		if ipLen == 16 {
+			for i := 4; i < 16; i++ {
+				ip[i] ^= txID[i-4]
+			}
 		}
 	}
 	return &net.UDPAddr{IP: ip, Port: int(port)}, nil
@@ -173,14 +176,14 @@ func parseAddress(attrType uint16, data []byte) (*net.UDPAddr, error) {
 func (m *stunMessage) GetMappedAddress() *net.UDPAddr {
 	for _, attr := range m.Attributes {
 		if attr.Type == attrXorMappedAddress {
-			if addr, err := parseAddress(attr.Type, attr.Value); err == nil {
+			if addr, err := parseAddress(attr.Type, attr.Value, m.Header.ID); err == nil {
 				return addr
 			}
 		}
 	}
 	for _, attr := range m.Attributes {
 		if attr.Type == attrMappedAddress {
-			if addr, err := parseAddress(attr.Type, attr.Value); err == nil {
+			if addr, err := parseAddress(attr.Type, attr.Value, m.Header.ID); err == nil {
 				return addr
 			}
 		}
@@ -193,14 +196,14 @@ func (m *stunMessage) GetMappedAddress() *net.UDPAddr {
 func (m *stunMessage) GetChangedAddress() *net.UDPAddr {
 	for _, attr := range m.Attributes {
 		if attr.Type == attrChangedAddress {
-			if addr, err := parseAddress(attr.Type, attr.Value); err == nil {
+			if addr, err := parseAddress(attr.Type, attr.Value, m.Header.ID); err == nil {
 				return addr
 			}
 		}
 	}
 	for _, attr := range m.Attributes {
 		if attr.Type == attrOtherAddress {
-			if addr, err := parseAddress(attr.Type, attr.Value); err == nil {
+			if addr, err := parseAddress(attr.Type, attr.Value, m.Header.ID); err == nil {
 				return addr
 			}
 		}