mieru: add mtu and handshake_mode options

docs/configuration/inbound/mieru.md

@@ -19,6 +19,7 @@ icon: material/new-box
     }
   ],
   "traffic_pattern": "GgQIARAK",
+  "mtu": 1400
 }
 ```
 
@@ -47,3 +48,7 @@ A base64 string to fine tune network behavior.
 #### user_hint_is_mandatory
 
 If proxy client doesn't sent user hint, proxy server will refuse the connection.
+
+#### mtu
+
+Maximum transmission unit of L2 payload. Only applies to UDP transport egress traffic.

docs/configuration/inbound/mieru.zh.md

@@ -19,6 +19,7 @@ icon: material/new-box
     }
   ],
   "traffic_pattern": "GgQIARAK",
+  "mtu": 1400
 }
 ```
 
@@ -47,3 +48,7 @@ icon: material/new-box
 #### user_hint_is_mandatory
 
 客户端若不发送用户提示，代理服务器将拒绝连接。
+
+#### mtu
+
+L2 载荷的最大传输单元。仅适用于 UDP 传输方式的出站流量。

docs/configuration/outbound/mieru.md

@@ -20,6 +20,8 @@ icon: material/new-box
   "password": "hjkl",
   "multiplexing": "MULTIPLEXING_LOW",
   "traffic_pattern": "GgQIARAK",
+  "mtu": 1400,
+  "handshake_mode": "HANDSHAKE_STANDARD",
 
   ... // Dial Fields
 }
@@ -71,6 +73,14 @@ Multiplexing level. Supported values are `MULTIPLEXING_OFF`, `MULTIPLEXING_LOW`,
 
 A base64 string to fine tune network behavior.
 
+#### mtu
+
+Maximum transmission unit of L2 payload. Only applies to UDP transport egress traffic.
+
+#### handshake_mode
+
+Handshake mode when the client opens a connection. Allowed values are `HANDSHAKE_STANDARD` (1-RTT, wait for the proxy server to establish the connection to the destination before sending payload) and `HANDSHAKE_NO_WAIT` (0-RTT, send payload together with the connection to the proxy server).
+
 ### Dial Fields
 
 See [Dial Fields](/configuration/shared/dial/) for details.

docs/configuration/outbound/mieru.zh.md

@@ -20,6 +20,8 @@ icon: material/new-box
   "password": "hjkl",
   "multiplexing": "MULTIPLEXING_LOW",
   "traffic_pattern": "GgQIARAK",
+  "mtu": 1400,
+  "handshake_mode": "HANDSHAKE_STANDARD",
 
   ... // 拨号字段
 }
@@ -71,6 +73,14 @@ mieru 密码。
 
 一个 base64 字符串用于微调网络行为。
 
+#### mtu
+
+L2 载荷的最大传输单元。仅适用于 UDP 传输方式的出站流量。
+
+#### handshake_mode
+
+客户端建立连接时的握手模式。可设为 `HANDSHAKE_STANDARD`（1-RTT，客户端等待代理服务器建立到目标地址的连接后再发送载荷）或 `HANDSHAKE_NO_WAIT`（0-RTT，客户端在连接代理服务器的同时发送载荷）。
+
 ### 拨号字段
 
 参阅 [拨号字段](/zh/configuration/shared/dial/)。

examples/mieru/client.json

@@ -36,7 +36,10 @@
       // valid: MULTIPLEXING_DEFAULT / MULTIPLEXING_OFF / MULTIPLEXING_LOW
       //        MULTIPLEXING_MIDDLE / MULTIPLEXING_HIGH
       "multiplexing": "MULTIPLEXING_LOW",
-      "traffic_pattern": "GgQIARAK"
+      "traffic_pattern": "GgQIARAK",
+      "mtu": 1400,
+      // valid: HANDSHAKE_DEFAULT / HANDSHAKE_STANDARD / HANDSHAKE_NO_WAIT
+      "handshake_mode": "HANDSHAKE_STANDARD"
     }
   ],
   "route": {

examples/mieru/server.json

@@ -17,7 +17,8 @@
           "password": "password"
         }
       ],
-      "traffic_pattern": "GgQIARAK"
+      "traffic_pattern": "GgQIARAK",
+      "mtu": 1400
     }
   ],
   "outbounds": [

option/mieru.go

@@ -11,6 +11,8 @@ type MieruOutboundOptions struct {
 	Password         string                     `json:"password,omitempty"`
 	Multiplexing     string                     `json:"multiplexing,omitempty"`
 	TrafficPattern   string                     `json:"traffic_pattern,omitempty"`
+	MTU              uint32                     `json:"mtu,omitempty"`
+	HandshakeMode    string                     `json:"handshake_mode,omitempty"`
 }
 
 type MieruInboundOptions struct {
@@ -20,6 +22,7 @@ type MieruInboundOptions struct {
 	Transport           string                     `json:"transport,omitempty"`
 	TrafficPattern      string                     `json:"traffic_pattern,omitempty"`
 	UserHintIsMandatory bool                       `json:"user_hint_is_mandatory,omitempty"`
+	MTU                 uint32                     `json:"mtu,omitempty"`
 }
 
 type MieruUser struct {

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 {