Fix socks5 UDP implementation

protocol/http/handshake.go

@@ -21,17 +21,14 @@ import (
 	"github.com/sagernet/sing/common/pipe"
 )
 
-// Deprecated: Use HandleConnectionEx instead.
+func HandleConnectionEx(
-func HandleConnection(ctx context.Context, conn net.Conn, reader *std_bufio.Reader, authenticator *auth.Authenticator,
+	ctx context.Context,
-	//nolint:staticcheck
+	conn net.Conn,
-	handler N.TCPConnectionHandler, metadata M.Metadata,
+	reader *std_bufio.Reader,
-) error {
+	authenticator *auth.Authenticator,
-	return HandleConnectionEx(ctx, conn, reader, authenticator, handler, nil, metadata.Source, nil)
+	handler N.TCPConnectionHandlerEx,
-}
+	source M.Socksaddr,
-
+	onClose N.CloseHandlerFunc,
-func HandleConnectionEx(ctx context.Context, conn net.Conn, reader *std_bufio.Reader, authenticator *auth.Authenticator,
-	//nolint:staticcheck
-	handler N.TCPConnectionHandler, handlerEx N.TCPConnectionHandlerEx, source M.Socksaddr, onClose N.CloseHandlerFunc,
 ) error {
 	for {
 		request, err := ReadRequest(reader)
@@ -105,13 +102,8 @@ func HandleConnectionEx(ctx context.Context, conn net.Conn, reader *std_bufio.Re
 			} else {
 				requestConn = conn
 			}
-			if handler != nil {
+			handler.NewConnectionEx(ctx, requestConn, source, destination, onClose)
-				//nolint:staticcheck
+			return nil
-				return handler.NewConnection(ctx, requestConn, M.Metadata{Protocol: "http", Source: source, Destination: destination})
-			} else {
-				handlerEx.NewConnectionEx(ctx, requestConn, source, destination, onClose)
-				return nil
-			}
 		} else if strings.ToLower(request.Header.Get("Connection")) == "upgrade" {
 			destination := M.ParseSocksaddrHostPortStr(request.URL.Hostname(), request.URL.Port())
 			if destination.Port == 0 {
@@ -124,19 +116,11 @@ func HandleConnectionEx(ctx context.Context, conn net.Conn, reader *std_bufio.Re
 			}
 			serverConn, clientConn := pipe.Pipe()
 			go func() {
-				if handler != nil {
+				handler.NewConnectionEx(ctx, clientConn, source, destination, func(it error) {
-					//nolint:staticcheck
+					if it != nil {
-					err := handler.NewConnection(ctx, clientConn, M.Metadata{Protocol: "http", Source: source, Destination: destination})
-					if err != nil {
 						common.Close(serverConn, clientConn)
 					}
-				} else {
+				})
-					handlerEx.NewConnectionEx(ctx, clientConn, source, destination, func(it error) {
-						if it != nil {
-							common.Close(serverConn, clientConn)
-						}
-					})
-				}
 			}()
 			err = request.Write(serverConn)
 			if err != nil {
@@ -150,7 +134,7 @@ func HandleConnectionEx(ctx context.Context, conn net.Conn, reader *std_bufio.Re
 			}
 			return bufio.CopyConn(ctx, conn, serverConn)
 		} else {
-			err = handleHTTPConnection(ctx, handler, handlerEx, conn, request, source)
+			err = handleHTTPConnection(ctx, handler, conn, request, source)
 			if err != nil {
 				return err
 			}
@@ -160,9 +144,7 @@ func HandleConnectionEx(ctx context.Context, conn net.Conn, reader *std_bufio.Re
 
 func handleHTTPConnection(
 	ctx context.Context,
-	//nolint:staticcheck
+	handler N.TCPConnectionHandlerEx,
-	handler N.TCPConnectionHandler,
-	handlerEx N.TCPConnectionHandlerEx,
 	conn net.Conn,
 	request *http.Request, source M.Socksaddr,
 ) error {
@@ -188,21 +170,10 @@ func handleHTTPConnection(
 			DisableCompression: true,
 			DialContext: func(ctx context.Context, network, address string) (net.Conn, error) {
 				input, output := pipe.Pipe()
-				if handler != nil {
+				go handler.NewConnectionEx(ctx, output, source, M.ParseSocksaddr(address), func(it error) {
-					go func() {
+					innerErr.Store(it)
-						//nolint:staticcheck
+					common.Close(input, output)
-						hErr := handler.NewConnection(ctx, output, M.Metadata{Protocol: "http", Source: source, Destination: M.ParseSocksaddr(address)})
+				})
-						if hErr != nil {
-							innerErr.Store(hErr)
-							common.Close(input, output)
-						}
-					}()
-				} else {
-					go handlerEx.NewConnectionEx(ctx, output, source, M.ParseSocksaddr(address), func(it error) {
-						innerErr.Store(it)
-						common.Close(input, output)
-					})
-				}
 				return input, nil
 			},
 		},

protocol/socks/handshake.go

@@ -19,14 +19,6 @@ import (
 	"github.com/sagernet/sing/protocol/socks/socks5"
 )
 
-// Deprecated: Use HandlerEx instead.
-//
-//nolint:staticcheck
-type Handler interface {
-	N.TCPConnectionHandler
-	N.UDPConnectionHandler
-}
-
 type HandlerEx interface {
 	N.TCPConnectionHandlerEx
 	N.UDPConnectionHandlerEx
@@ -87,6 +79,26 @@ func ClientHandshake5(conn io.ReadWriter, command byte, destination M.Socksaddr,
 	} else if authResponse.Method != socks5.AuthTypeNotRequired {
 		return socks5.Response{}, E.New("socks5: unsupported auth method: ", authResponse.Method)
 	}
+
+	if command == socks5.CommandUDPAssociate {
+		if destination.Addr.IsPrivate() {
+			if destination.Addr.Is6() {
+				destination.Addr = netip.AddrFrom4([4]byte{127, 0, 0, 1})
+			} else {
+				destination.Addr = netip.IPv6Loopback()
+			}
+		} else if destination.Addr.IsGlobalUnicast() {
+			if destination.Addr.Is6() {
+				destination.Addr = netip.IPv6Unspecified()
+			} else {
+				destination.Addr = netip.IPv4Unspecified()
+			}
+		} else {
+			destination.Addr = netip.IPv6Unspecified()
+		}
+		destination.Port = 0
+	}
+
 	err = socks5.WriteRequest(conn, socks5.Request{
 		Command:     command,
 		Destination: destination,
@@ -104,23 +116,11 @@ func ClientHandshake5(conn io.ReadWriter, command byte, destination M.Socksaddr,
 	return response, err
 }
 
-// Deprecated: use HandleConnectionEx instead.
-func HandleConnection(ctx context.Context, conn net.Conn, authenticator *auth.Authenticator, handler Handler, metadata M.Metadata) error {
-	return HandleConnection0(ctx, conn, std_bufio.NewReader(conn), authenticator, handler, metadata)
-}
-
-// Deprecated: Use HandleConnectionEx instead.
-func HandleConnection0(ctx context.Context, conn net.Conn, reader *std_bufio.Reader, authenticator *auth.Authenticator, handler Handler, metadata M.Metadata) error {
-	return HandleConnectionEx(ctx, conn, reader, authenticator, handler, nil, metadata.Source, metadata.Destination, nil)
-}
-
 func HandleConnectionEx(
 	ctx context.Context, conn net.Conn, reader *std_bufio.Reader,
 	authenticator *auth.Authenticator,
-	//nolint:staticcheck
+	handler HandlerEx,
-	handler Handler,
+	source M.Socksaddr,
-	handlerEx HandlerEx,
-	source M.Socksaddr, destination M.Socksaddr,
 	onClose N.CloseHandlerFunc,
 ) error {
 	version, err := reader.ReadByte()
@@ -145,20 +145,7 @@ func HandleConnectionEx(
 				}
 				return E.New("socks4: authentication failed, username=", request.Username)
 			}
-			destination = request.Destination
+			handler.NewConnectionEx(auth.ContextWithUser(ctx, request.Username), NewLazyConn(conn, version), source, request.Destination, onClose)
-			if handlerEx != nil {
-				handlerEx.NewConnectionEx(auth.ContextWithUser(ctx, request.Username), NewLazyConn(conn, version), source, destination, onClose)
-			} else {
-				err = socks4.WriteResponse(conn, socks4.Response{
-					ReplyCode:   socks4.ReplyCodeGranted,
-					Destination: M.SocksaddrFromNet(conn.LocalAddr()),
-				})
-				if err != nil {
-					return err
-				}
-				//nolint:staticcheck
-				return handler.NewConnection(auth.ContextWithUser(ctx, request.Username), conn, M.Metadata{Protocol: "socks4", Source: source, Destination: destination})
-			}
 			return nil
 		default:
 			err = socks4.WriteResponse(conn, socks4.Response{
@@ -223,53 +210,15 @@ func HandleConnectionEx(
 		}
 		switch request.Command {
 		case socks5.CommandConnect:
-			destination = request.Destination
+			handler.NewConnectionEx(ctx, NewLazyConn(conn, version), source, request.Destination, onClose)
-			if handlerEx != nil {
+			return nil
-				handlerEx.NewConnectionEx(ctx, NewLazyConn(conn, version), source, destination, onClose)
-				return nil
-			} else {
-				err = socks5.WriteResponse(conn, socks5.Response{
-					ReplyCode: socks5.ReplyCodeSuccess,
-					Bind:      M.SocksaddrFromNet(conn.LocalAddr()),
-				})
-				if err != nil {
-					return err
-				}
-				//nolint:staticcheck
-				return handler.NewConnection(ctx, conn, M.Metadata{Protocol: "socks5", Source: source, Destination: destination})
-			}
 		case socks5.CommandUDPAssociate:
 			var udpConn *net.UDPConn
 			udpConn, err = net.ListenUDP(M.NetworkFromNetAddr("udp", M.AddrFromNet(conn.LocalAddr())), net.UDPAddrFromAddrPort(netip.AddrPortFrom(M.AddrFromNet(conn.LocalAddr()), 0)))
 			if err != nil {
 				return err
 			}
-			if handlerEx == nil {
+			handler.NewPacketConnectionEx(ctx, NewLazyAssociatePacketConn(bufio.NewServerPacketConn(udpConn), conn), source, M.Socksaddr{}, onClose)
-				defer udpConn.Close()
-				err = socks5.WriteResponse(conn, socks5.Response{
-					ReplyCode: socks5.ReplyCodeSuccess,
-					Bind:      M.SocksaddrFromNet(udpConn.LocalAddr()),
-				})
-				if err != nil {
-					return err
-				}
-				destination = request.Destination
-				associatePacketConn := NewAssociatePacketConn(bufio.NewServerPacketConn(udpConn), destination, conn)
-				var innerError error
-				done := make(chan struct{})
-				go func() {
-					//nolint:staticcheck
-					innerError = handler.NewPacketConnection(ctx, associatePacketConn, M.Metadata{Protocol: "socks5", Source: source, Destination: destination})
-					close(done)
-				}()
-				err = common.Error(io.Copy(io.Discard, conn))
-				associatePacketConn.Close()
-				<-done
-				return E.Errors(innerError, err)
-			} else {
-				handlerEx.NewPacketConnectionEx(ctx, NewLazyAssociatePacketConn(bufio.NewServerPacketConn(udpConn), destination, conn), source, destination, onClose)
-				return nil
-			}
 		default:
 			err = socks5.WriteResponse(conn, socks5.Response{
 				ReplyCode: socks5.ReplyCodeUnsupported,

protocol/socks/lazy.go

@@ -105,12 +105,11 @@ type LazyAssociatePacketConn struct {
 	responseWritten bool
 }
 
-func NewLazyAssociatePacketConn(conn net.Conn, remoteAddr M.Socksaddr, underlying net.Conn) *LazyAssociatePacketConn {
+func NewLazyAssociatePacketConn(conn net.Conn, underlying net.Conn) *LazyAssociatePacketConn {
 	return &LazyAssociatePacketConn{
 		AssociatePacketConn: AssociatePacketConn{
 			AbstractConn: conn,
 			conn:         bufio.NewExtendedConn(conn),
-			remoteAddr:   remoteAddr,
 			underlying:   underlying,
 		},
 	}