refactor peeking strategy

app/dispatcher/impl/default.go

@@ -4,6 +4,7 @@ package impl
 
 import (
 	"context"
+
 	"time"
 
 	"v2ray.com/core/app"
@@ -81,24 +82,7 @@ func (d *DefaultDispatcher) Dispatch(ctx context.Context, destination net.Destin
 	return outbound, nil
 }
 
-func snifer(ctx context.Context, sniferList []proxyman.KnownProtocols, outbound ray.OutboundRay) (string, error) {
+func trySnif(sniferList []proxyman.KnownProtocols, b []byte) (string, error) {
-	payload := buf.New()
-	defer payload.Release()
-
-	totalAttempt := 0
-	for {
-		select {
-		case <-ctx.Done():
-			return "", ctx.Err()
-		case <-time.After(time.Millisecond * 100):
-			totalAttempt++
-			if totalAttempt > 5 {
-				return "", errSniffingTimeout
-			}
-			outbound.OutboundInput().Peek(payload)
-			if payload.IsEmpty() {
-				continue
-			}
 	for _, protocol := range sniferList {
 		var f func([]byte) (string, error)
 		switch protocol {
@@ -110,7 +94,31 @@ func snifer(ctx context.Context, sniferList []proxyman.KnownProtocols, outbound
 			panic("Unsupported protocol")
 		}
 
-				domain, err := f(payload.Bytes())
+		domain, err := f(b)
+		if err != ErrMoreData {
+			return domain, err
+		}
+	}
+	return "", ErrMoreData
+}
+
+func snifer(ctx context.Context, sniferList []proxyman.KnownProtocols, outbound ray.OutboundRay) (string, error) {
+	payload := buf.New()
+	defer payload.Release()
+
+	totalAttempt := 0
+	for {
+		select {
+		case <-ctx.Done():
+			return "", ctx.Err()
+		default:
+			totalAttempt++
+			if totalAttempt > 5 {
+				return "", errSniffingTimeout
+			}
+			outbound.OutboundInput().Peek(payload)
+			if !payload.IsEmpty() {
+				domain, err := trySnif(sniferList, payload.Bytes())
 				if err != ErrMoreData {
 					return domain, err
 				}
@@ -118,6 +126,7 @@ func snifer(ctx context.Context, sniferList []proxyman.KnownProtocols, outbound
 			if payload.IsFull() {
 				return "", ErrInvalidData
 			}
+			time.Sleep(time.Millisecond * 100)
 		}
 	}
 }