test case for passive connection

testing/scenarios/data/test_1_client.json

@@ -1,4 +1,7 @@
 {
+  "log": {
+    "loglevel": "debug"
+  },
   "inbound": {
     "port": 50000,
     "listen": "127.0.0.1",
@@ -9,6 +12,19 @@
       "ip": "127.0.0.1"
     }
   },
+  "inboundDetour": [
+    {
+      "port": 50002,
+      "listen": "127.0.0.1",
+      "protocol": "socks",
+      "allowPassive": true,
+      "settings": {
+        "auth": "noauth",
+        "udp": true,
+        "ip": "127.0.0.1"
+      }
+    }
+  ],
   "outbound": {
     "protocol": "vmess",
     "settings": {

testing/scenarios/data/test_1_server.json

@@ -1,11 +1,12 @@
 {
   "port": 50001,
   "log": {
-    "loglevel": "none"
+    "loglevel": "debug"
   },
   "inbound": {
     "listen": "127.0.0.1",
     "protocol": "vmess",
+    "allowPassive": true,
     "settings": {
       "clients": [
         {
@@ -31,6 +32,7 @@
       "listen": "127.0.0.1",
       "port": "50005-50009",
       "tag": "detour",
+      "allowPassive": true,
       "settings": {
         "clients": [
           {

testing/scenarios/socks_end_test.go

@@ -83,6 +83,63 @@ func TestTCPConnection(t *testing.T) {
 	CloseAllServers()
 }
 
+func TestPassiveTCPConnection(t *testing.T) {
+	assert := assert.On(t)
+
+	tcpServer := &tcp.Server{
+		MsgProcessor: func(data []byte) []byte {
+			buffer := make([]byte, 0, 2048)
+			buffer = append(buffer, []byte("Processed: ")...)
+			buffer = append(buffer, data...)
+			return buffer
+		},
+		SendFirst: []byte("Server sends first."),
+	}
+	_, err := tcpServer.Start()
+	assert.Error(err).IsNil()
+	defer tcpServer.Close()
+
+	assert.Error(InitializeServerSetOnce("test_1")).IsNil()
+
+	socksPort := v2net.Port(50002)
+
+	conn, err := net.DialTCP("tcp", nil, &net.TCPAddr{
+		IP:   []byte{127, 0, 0, 1},
+		Port: int(socksPort),
+	})
+	assert.Error(err).IsNil()
+
+	authRequest := socks5AuthMethodRequest(byte(0))
+	nBytes, err := conn.Write(authRequest)
+	assert.Int(nBytes).Equals(len(authRequest))
+	assert.Error(err).IsNil()
+
+	authResponse := make([]byte, 1024)
+	nBytes, err = conn.Read(authResponse)
+	assert.Error(err).IsNil()
+	assert.Bytes(authResponse[:nBytes]).Equals([]byte{socks5Version, 0})
+
+	connectRequest := socks5Request(byte(1), v2net.TCPDestination(v2net.IPAddress([]byte{127, 0, 0, 1}), tcpServer.Port))
+	nBytes, err = conn.Write(connectRequest)
+	assert.Int(nBytes).Equals(len(connectRequest))
+	assert.Error(err).IsNil()
+
+	connectResponse := make([]byte, 1024)
+	nBytes, err = conn.Read(connectResponse)
+	assert.Error(err).IsNil()
+	assert.Bytes(connectResponse[:nBytes]).Equals([]byte{socks5Version, 0, 0, 1, 0, 0, 0, 0, 6, 181})
+
+	actualResponse := make([]byte, 1024)
+	nResponse, err := conn.Read(actualResponse)
+	assert.Error(err).IsNil()
+
+	assert.String(string(actualResponse[:nResponse])).Equals(string(tcpServer.SendFirst))
+
+	conn.Close()
+
+	CloseAllServers()
+}
+
 func TestTCPBind(t *testing.T) {
 	assert := assert.On(t)
 

testing/servers/tcp/tcp.go

@@ -10,6 +10,7 @@ import (
 type Server struct {
 	Port         v2net.Port
 	MsgProcessor func(msg []byte) []byte
+	SendFirst    []byte
 	accepting    bool
 	listener     *net.TCPListener
 }
@@ -44,6 +45,9 @@ func (server *Server) acceptConnections(listener *net.TCPListener) {
 }
 
 func (server *Server) handleConnection(conn net.Conn) {
+	if len(server.SendFirst) > 0 {
+		conn.Write(server.SendFirst)
+	}
 	request := make([]byte, 4096)
 	for true {
 		nBytes, err := conn.Read(request)