remove SOCKS4 suppport for auto handler

README.md

@@ -117,11 +117,12 @@ scheme://[bind_address]:port/[host]:hostport
     "ChainNodes": [
         "http://192.168.1.1:8080",
         "https://10.0.2.1:443"
-    ]
+    ],
+    "Debug": true
 }
 ```
 
-ServeNodes等同于-L参数，ChainNodes等同于-F参数
+`ServeNodes`等同于`-L`参数，`ChainNodes`等同于`-F`参数，`Debug`等同于`-D`参数。
 
 
 使用方法

README_en.md

@@ -117,11 +117,12 @@ The configuration file is in standard JSON format:
     "ChainNodes": [
         "http://192.168.1.1:8080",
         "https://10.0.2.1:443"
-    ]
+    ],
+    "Debug": true
 }
 ```
 
-ServeNodes is equivalent to the -L parameter, ChainNodes is equivalent to the -F parameter.
+`ServeNodes` is equivalent to the `-L` parameter, `ChainNodes` is equivalent to the `-F` parameter, `Debug` is equivalent to the `-D` parameter.
 
 Usage
 ------

cmd/gost/main.go

@@ -24,7 +24,7 @@ import (
 var (
 	options struct {
 		ChainNodes, ServeNodes stringList
-		DebugMode              bool
+		Debug                  bool
 	}
 )
 
@@ -37,7 +37,7 @@ func init() {
 	flag.Var(&options.ChainNodes, "F", "forward address, can make a forward chain")
 	flag.Var(&options.ServeNodes, "L", "listen address, can listen on multiple ports")
 	flag.StringVar(&configureFile, "C", "", "configure file")
-	flag.BoolVar(&options.DebugMode, "D", false, "enable debug log")
+	flag.BoolVar(&options.Debug, "D", false, "enable debug log")
 	flag.BoolVar(&printVersion, "V", false, "print version")
 	flag.Parse()
 
@@ -57,7 +57,7 @@ func init() {
 	}
 
 	gost.SetLogger(&gost.LogLogger{})
-	gost.Debug = options.DebugMode
+	gost.Debug = options.Debug
 }
 
 func main() {

handler.go

@@ -96,7 +96,7 @@ func (h *autoHandler) Handle(conn net.Conn) {
 	cc := &bufferdConn{Conn: conn, br: br}
 	switch b[0] {
 	case gosocks4.Ver4:
-		SOCKS4Handler(h.options...).Handle(cc)
+		return // SOCKS4(a) does not suppport authentication method, so we ignore it.
 	case gosocks5.Ver5:
 		SOCKS5Handler(h.options...).Handle(cc)
 	default: // http