fix udpdomain v4 issue

app/proxyman/outbound/handler.go

@@ -267,6 +267,13 @@ func (h *Handler) DestIpAddress() net.IP {
 	return internet.DestIpAddress()
 }
 
+func (h *Handler) SocketSettings() *internet.SocketConfig {
+	if h.streamSettings == nil {
+		return nil
+	}
+	return h.streamSettings.SocketSettings
+}
+
 // Dial implements internet.Dialer.
 func (h *Handler) Dial(ctx context.Context, dest net.Destination) (stat.Connection, error) {
 	if h.senderSettings != nil {

proxy/freedom/freedom.go

@@ -38,6 +38,11 @@ var defaultBlockAllRule *FinalRule
 func init() {
 	common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
 		h := new(Handler)
+		if handler, ok := session.FullHandlerFromContext(ctx).(handlerWithSocketSettings); ok {
+			if sockopt := handler.SocketSettings(); sockopt != nil {
+				h.socketStrategy = sockopt.DomainStrategy
+			}
+		}
 		if err := core.RequireFeatures(ctx, func(pm policy.Manager) error {
 			return h.Init(config.(*Config), pm)
 		}); err != nil {
@@ -88,6 +93,10 @@ func init() {
 	}
 }
 
+type handlerWithSocketSettings interface {
+	SocketSettings() *internet.SocketConfig
+}
+
 type FinalRule struct {
 	action     RuleAction
 	network    [8]bool
@@ -98,9 +107,10 @@ type FinalRule struct {
 
 // Handler handles Freedom connections.
 type Handler struct {
-	policyManager policy.Manager
-	config        *Config
-	finalRules    []*FinalRule
+	policyManager  policy.Manager
+	config         *Config
+	finalRules     []*FinalRule
+	socketStrategy internet.DomainStrategy
 }
 
 func buildFinalRule(config *FinalRuleConfig) (*FinalRule, error) {
@@ -246,6 +256,13 @@ func (h *Handler) blockDelay(rule *FinalRule) time.Duration {
 	return time.Duration(min+uint64(dice.Roll(int(abs+1)))) * time.Second
 }
 
+func (h *Handler) udpDomainStrategy() internet.DomainStrategy {
+	if h.config.DomainStrategy.HasStrategy() {
+		return h.config.DomainStrategy
+	}
+	return h.socketStrategy
+}
+
 func isValidAddress(addr *net.IPOrDomain) bool {
 	if addr == nil {
 		return false
@@ -406,7 +423,7 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
 				writer = buf.NewWriter(conn)
 			}
 		} else {
-			writer = NewPacketWriter(conn, h, defaultRule, UDPOverride, destination)
+			writer = NewPacketWriter(conn, h, defaultRule, UDPOverride, destination, outGateway)
 			if h.config.Noises != nil {
 				errors.LogDebug(ctx, "NOISE", h.config.Noises)
 				writer = &NoisePacketWriter{
@@ -535,7 +552,7 @@ func (r *PacketReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
 }
 
 // DialDest means the dial target used in the dialer when creating conn
-func NewPacketWriter(conn net.Conn, h *Handler, defaultRule *FinalRule, UDPOverride net.Destination, DialDest net.Destination) buf.Writer {
+func NewPacketWriter(conn net.Conn, h *Handler, defaultRule *FinalRule, UDPOverride net.Destination, DialDest net.Destination, outGateway net.Address) buf.Writer {
 	iConn := conn
 	statConn, ok := iConn.(*stat.CounterConnection)
 	if ok {
@@ -559,7 +576,7 @@ func NewPacketWriter(conn net.Conn, h *Handler, defaultRule *FinalRule, UDPOverr
 			DefaultRule:       defaultRule,
 			UDPOverride:       UDPOverride,
 			ResolvedUDPAddr:   resolvedUDPAddr,
-			LocalAddr:         net.DestinationFromAddr(conn.LocalAddr()).Address,
+			OutGateway:        outGateway,
 		}
 
 	}
@@ -578,7 +595,7 @@ type PacketWriter struct {
 	// Resulting in these packets being sent to many different IPs randomly
 	// So, cache and keep the resolve result
 	ResolvedUDPAddr *utils.TypedSyncMap[string, net.Address]
-	LocalAddr       net.Address
+	OutGateway      net.Address
 }
 
 func (w *PacketWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
@@ -601,21 +618,21 @@ func (w *PacketWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
 				if ip, ok := w.ResolvedUDPAddr.Load(b.UDP.Address.Domain()); ok {
 					b.UDP.Address = ip
 				} else {
-					ShouldUseSystemResolver := true
-					if w.Handler.config.DomainStrategy.HasStrategy() {
-						ips, err := internet.LookupForIP(b.UDP.Address.Domain(), w.Handler.config.DomainStrategy, w.LocalAddr)
+					shouldUseSystemResolver := true
+					if resolveStrategy := w.Handler.udpDomainStrategy(); resolveStrategy.HasStrategy() {
+						ips, err := internet.LookupForIP(b.UDP.Address.Domain(), w.Handler.config.DomainStrategy, w.OutGateway)
 						if err != nil {
 							// drop packet if resolve failed when forceIP
-							if w.Handler.config.DomainStrategy.ForceIP() {
+							if resolveStrategy.ForceIP() {
 								b.Release()
 								continue
 							}
 						} else {
 							ip = net.IPAddress(ips[dice.Roll(len(ips))])
-							ShouldUseSystemResolver = false
+							shouldUseSystemResolver = false
 						}
 					}
-					if ShouldUseSystemResolver {
+					if shouldUseSystemResolver {
 						udpAddr, err := net.ResolveUDPAddr("udp", b.UDP.NetAddr())
 						if err != nil {
 							b.Release()