mieru: add mtu and handshake_mode options

protocol/mieru/inbound.go

@@ -309,13 +309,17 @@ func buildMieruServerConfig(_ context.Context, options option.MieruInboundOption
 			UserHintIsMandatory: proto.Bool(true),
 		}
 	}
+	config := &mierupb.ServerConfig{
+		PortBindings:     portBindings,
+		Users:            users,
+		TrafficPattern:   trafficPattern,
+		AdvancedSettings: advancedSettings,
+	}
+	if options.MTU != 0 {
+		config.Mtu = proto.Int32(int32(options.MTU))
+	}
 	return &mieruserver.ServerConfig{
-		Config: &mierupb.ServerConfig{
-			PortBindings:     portBindings,
-			Users:            users,
-			TrafficPattern:   trafficPattern,
-			AdvancedSettings: advancedSettings,
-		},
+		Config: config,
 	}, userNames, nil
 }
 

protocol/mieru/outbound.go

@@ -235,6 +235,12 @@ func buildMieruClientConfig(options option.MieruOutboundOptions, dialer mieruDia
 			Level: mierupb.MultiplexingLevel(multiplexing).Enum(),
 		}
 	}
+	if options.MTU != 0 {
+		config.Profile.Mtu = proto.Int32(int32(options.MTU))
+	}
+	if handshakeMode, ok := mierupb.HandshakeMode_value[options.HandshakeMode]; ok {
+		config.Profile.HandshakeMode = mierupb.HandshakeMode(handshakeMode).Enum()
+	}
 	if options.TrafficPattern != "" {
 		trafficPattern, _ := mierutp.Decode(options.TrafficPattern)
 		config.Profile.TrafficPattern = trafficPattern
@@ -278,6 +284,11 @@ func validateMieruOptions(options option.MieruOutboundOptions) error {
 			return fmt.Errorf("invalid multiplexing level: %s", options.Multiplexing)
 		}
 	}
+	if options.HandshakeMode != "" {
+		if _, ok := mierupb.HandshakeMode_value[options.HandshakeMode]; !ok {
+			return fmt.Errorf("invalid handshake mode: %s", options.HandshakeMode)
+		}
+	}
 	if options.TrafficPattern != "" {
 		trafficPattern, err := mierutp.Decode(options.TrafficPattern)
 		if err != nil {