XTLS protocol: Apply Vision's padding to XUDP Mux & Minor fixes

It's recommended to enable XUDP Mux when using XTLS Vision
Thank @yuhan6665 for testing

proxy/vless/encoding/encoding.go

@@ -21,6 +21,7 @@ import (
 	"github.com/xtls/xray-core/common/signal"
 	"github.com/xtls/xray-core/features/stats"
 	"github.com/xtls/xray-core/proxy/vless"
+	"github.com/xtls/xray-core/transport/internet/reality"
 	"github.com/xtls/xray-core/transport/internet/stat"
 	"github.com/xtls/xray-core/transport/internet/tls"
 )
@@ -227,8 +228,10 @@ func XtlsRead(reader buf.Reader, writer buf.Writer, timer signal.ActivityUpdater
 						if ok {
 							iConn = statConn.Connection
 						}
-						if xc, ok := iConn.(*tls.Conn); ok {
-							iConn = xc.NetConn()
+						if tlsConn, ok := iConn.(*tls.Conn); ok {
+							iConn = tlsConn.NetConn()
+						} else if realityConn, ok := iConn.(*reality.Conn); ok {
+							iConn = realityConn.NetConn()
 						}
 						if tc, ok := iConn.(*net.TCPConn); ok {
 							newError("XtlsRead splice").WriteToLog(session.ExportIDToError(ctx))

proxy/vless/inbound/inbound.go

@@ -456,10 +456,10 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
 	case vless.XRV:
 		if account.Flow == requestAddons.Flow {
 			switch request.Command {
-			case protocol.RequestCommandMux:
-				return newError(requestAddons.Flow + " doesn't support Mux").AtWarning()
 			case protocol.RequestCommandUDP:
 				return newError(requestAddons.Flow + " doesn't support UDP").AtWarning()
+			case protocol.RequestCommandMux:
+				fallthrough // we will break Mux connections that contain TCP requests
 			case protocol.RequestCommandTCP:
 				var t reflect.Type
 				var p uintptr
@@ -474,10 +474,8 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
 					netConn = realityConn.NetConn()
 					t = reflect.TypeOf(realityConn.Conn).Elem()
 					p = uintptr(unsafe.Pointer(realityConn.Conn))
-				} else if _, ok := iConn.(*tls.UConn); ok {
-					return newError("XTLS only supports UTLS fingerprint for the outbound.").AtWarning()
 				} else {
-					return newError("XTLS only supports TCP, mKCP and DomainSocket for now.").AtWarning()
+					return newError("XTLS only supports TLS and REALITY directly for now.").AtWarning()
 				}
 				if pc, ok := netConn.(*proxyproto.Conn); ok {
 					netConn = pc.Raw()
@@ -495,7 +493,7 @@ func (h *Handler) Process(ctx context.Context, network net.Network, connection s
 			return newError(account.ID.String() + " is not able to use " + requestAddons.Flow).AtWarning()
 		}
 	case "":
-		if account.Flow == vless.XRV && request.Command == protocol.RequestCommandTCP {
+		if account.Flow == vless.XRV && (request.Command == protocol.RequestCommandTCP || isMuxAndNotXUDP(request, first)) {
 			return newError(account.ID.String() + " is not able to use \"\". Note that the pure TLS proxy has certain TLS in TLS characters.").AtWarning()
 		}
 	default:

proxy/vless/outbound/outbound.go

@@ -135,13 +135,13 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
 		fallthrough
 	case vless.XRV:
 		switch request.Command {
-		case protocol.RequestCommandMux:
-			requestAddons.Flow = "" // let server break Mux connections that contain TCP requests
 		case protocol.RequestCommandUDP:
 			if !allowUDP443 && request.Port == 443 {
 				return newError("XTLS rejected UDP/443 traffic").AtInfo()
 			}
 			requestAddons.Flow = ""
+		case protocol.RequestCommandMux:
+			fallthrough // let server break Mux connections that contain TCP requests
 		case protocol.RequestCommandTCP:
 			var t reflect.Type
 			var p uintptr
@@ -158,7 +158,7 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
 				t = reflect.TypeOf(realityConn.Conn).Elem()
 				p = uintptr(unsafe.Pointer(realityConn.Conn))
 			} else {
-				return newError("XTLS only supports TCP, mKCP and DomainSocket for now.").AtWarning()
+				return newError("XTLS only supports TLS and REALITY directly for now.").AtWarning()
 			}
 			if sc, ok := netConn.(syscall.Conn); ok {
 				rawConn, _ = sc.SyscallConn()