chore

proxy/socks/protocol.go

@@ -196,9 +196,6 @@ func (s *ServerSession) handshake5(nMethod byte, reader io.Reader, writer net.Co
 	var tempUDPConn *TempUDPConn
 	//nolint:gocritic // Use if else chain for clarity
 	if request.Command == protocol.RequestCommandUDP {
-		if request.Address.Family().IsDomain() {
-			return nil, nil, errors.New("domain name in UDP associate is illegal")
-		}
 		if s.config.Address != nil {
 			// Use configured IP as remote address in the response to UDP Associate
 			responseAddress = s.config.Address.AsAddress()
@@ -212,7 +209,9 @@ func (s *ServerSession) handshake5(nMethod byte, reader io.Reader, writer net.Co
 		}
 		responsePort = net.Port(udpHub.LocalAddr().(*net.UDPAddr).Port)
 		expectedRemote := &gonet.UDPAddr{}
-		if request.Address.IP().IsUnspecified() {
+		// if request address is a domain(udp associate should not have request domain)
+		// treat it as unspecified
+		if request.Address.Family().IsDomain() || request.Address.IP().IsUnspecified() {
 			expectedRemote.IP = writer.RemoteAddr().(*net.TCPAddr).IP // unix?
 		} else {
 			expectedRemote.IP = request.Address.IP()

proxy/socks/server.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	goerrors "errors"
 	"io"
+	"sync"
 	"time"
 
 	"github.com/xtls/xray-core/common"
@@ -216,18 +217,24 @@ func (s *Server) handleUDPPayload(ctx context.Context, conn stat.Connection, dis
 	defer udpServer.RemoveRay()
 
 	inbound := session.InboundFromContext(ctx)
-	if inbound != nil && inbound.Source.IsValid() {
-		errors.LogInfo(ctx, "client UDP connection from ", inbound.Source)
-	}
 
 	var dest *net.Destination
 
 	reader := buf.NewPacketReader(conn)
+	var changeRemote sync.Once
 	for {
 		mpayload, err := reader.ReadMultiBuffer()
 		if err != nil {
 			return err
 		}
+		changeRemote.Do(func() {
+			if inbound != nil {
+				// change source to real remote UDP address
+				inbound.Source = net.DestinationFromAddr(conn.RemoteAddr())
+				inbound.Local = net.DestinationFromAddr(conn.LocalAddr())
+				errors.LogInfo(ctx, "client UDP connection from ", inbound.Source)
+			}
+		})
 
 		for _, payload := range mpayload {
 			request, err := DecodeUDPPacket(payload)