Feature: support vmess 'zero' security (#2513)

transport/vmess/conn.go

@@ -35,6 +35,7 @@ type Conn struct {
 	respBodyKey []byte
 	respV       byte
 	security    byte
+	option      byte
 	isAead      bool
 
 	received bool
@@ -74,7 +75,7 @@ func (vc *Conn) sendRequest() error {
 	buf.Write(vc.reqBodyIV[:])
 	buf.Write(vc.reqBodyKey[:])
 	buf.WriteByte(vc.respV)
-	buf.WriteByte(OptionChunkStream)
+	buf.WriteByte(vc.option)
 
 	p := rand.Intn(16)
 	// P Sec Reserve Cmd
@@ -206,6 +207,7 @@ func newConn(conn net.Conn, id *ID, dst *DstAddr, security Security, isAead bool
 	copy(reqBodyIV[:], randBytes[:16])
 	copy(reqBodyKey[:], randBytes[16:32])
 	respV := randBytes[32]
+	option := OptionChunkStream
 
 	var (
 		respBodyKey []byte
@@ -227,6 +229,16 @@ func newConn(conn net.Conn, id *ID, dst *DstAddr, security Security, isAead bool
 	var writer io.Writer
 	var reader io.Reader
 	switch security {
+	case SecurityZero:
+		security = SecurityNone
+		if !dst.UDP {
+			reader = conn
+			writer = conn
+			option = 0
+		} else {
+			reader = newChunkReader(conn)
+			writer = newChunkWriter(conn)
+		}
 	case SecurityNone:
 		reader = newChunkReader(conn)
 		writer = newChunkWriter(conn)
@@ -267,6 +279,7 @@ func newConn(conn net.Conn, id *ID, dst *DstAddr, security Security, isAead bool
 		reader:      reader,
 		writer:      writer,
 		security:    security,
+		option:      option,
 		isAead:      isAead,
 	}
 	if err := c.sendRequest(); err != nil {

transport/vmess/vmess.go

@@ -26,15 +26,9 @@ const (
 	SecurityAES128GCM        Security = 3
 	SecurityCHACHA20POLY1305 Security = 4
 	SecurityNone             Security = 5
+	SecurityZero             Security = 6
 )
 
-// CipherMapping return
-var CipherMapping = map[string]byte{
-	"none":              SecurityNone,
-	"aes-128-gcm":       SecurityAES128GCM,
-	"chacha20-poly1305": SecurityCHACHA20POLY1305,
-}
-
 // Command types
 const (
 	CommandTCP byte = 1
@@ -95,6 +89,8 @@ func NewClient(config Config) (*Client, error) {
 		security = SecurityCHACHA20POLY1305
 	case "none":
 		security = SecurityNone
+	case "zero":
+		security = SecurityZero
 	case "auto":
 		security = SecurityCHACHA20POLY1305
 		if runtime.GOARCH == "amd64" || runtime.GOARCH == "s390x" || runtime.GOARCH == "arm64" {