From 3defc3fc77568aa07c2266d8a06fc934a3ed8a6c Mon Sep 17 00:00:00 2001
From: gVisor bot <gvisor-bot@google.com>
Date: Wed, 12 Apr 2023 11:09:31 +0800
Subject: [PATCH] chore: proxyDialer first using old function to let mux work

---
 component/proxydialer/proxydialer.go | 44 ++++++++--------------------
 dns/util.go                          | 16 +++++-----
 2 files changed, 20 insertions(+), 40 deletions(-)

diff --git a/component/proxydialer/proxydialer.go b/component/proxydialer/proxydialer.go
index 7fac628f..a32e54d1 100644
--- a/component/proxydialer/proxydialer.go
+++ b/component/proxydialer/proxydialer.go
@@ -45,23 +45,13 @@ func (p proxyDialer) DialContext(ctx context.Context, network, address string) (
 		return N.NewBindPacketConn(pc, currentMeta.UDPAddr()), nil
 	}
 	var conn C.Conn
-	switch p.proxy.SupportWithDialer() {
-	case C.ALLNet:
-		fallthrough
-	case C.TCP:
+	if d, ok := p.dialer.(dialer.Dialer); ok { // first using old function to let mux work
+		conn, err = p.proxy.DialContext(ctx, currentMeta, dialer.WithOption(d.Opt))
+	} else {
 		conn, err = p.proxy.DialContextWithDialer(ctx, p.dialer, currentMeta)
-		if err != nil {
-			return nil, err
-		}
-	default: // fallback to old function
-		if d, ok := p.dialer.(dialer.Dialer); ok { // fallback to old function
-			conn, err = p.proxy.DialContext(ctx, currentMeta, dialer.WithOption(d.Opt))
-			if err != nil {
-				return nil, err
-			}
-		} else {
-			return nil, C.ErrNotSupport
-		}
+	}
+	if err != nil {
+		return nil, err
 	}
 	if p.statistic {
 		conn = statistic.NewTCPTracker(conn, statistic.DefaultManager, currentMeta, nil, 0, 0, false)
@@ -81,23 +71,13 @@ func (p proxyDialer) listenPacket(ctx context.Context, currentMeta *C.Metadata)
 	var pc C.PacketConn
 	var err error
 	currentMeta.NetWork = C.UDP
-	switch p.proxy.SupportWithDialer() {
-	case C.ALLNet:
-		fallthrough
-	case C.UDP:
+	if d, ok := p.dialer.(dialer.Dialer); ok { // first using old function to let mux work
+		pc, err = p.proxy.ListenPacketContext(ctx, currentMeta, dialer.WithOption(d.Opt))
+	} else {
 		pc, err = p.proxy.ListenPacketWithDialer(ctx, p.dialer, currentMeta)
-		if err != nil {
-			return nil, err
-		}
-	default: // fallback to old function
-		if d, ok := p.dialer.(dialer.Dialer); ok { // fallback to old function
-			pc, err = p.proxy.ListenPacketContext(ctx, currentMeta, dialer.WithOption(d.Opt))
-			if err != nil {
-				return nil, err
-			}
-		} else {
-			return nil, C.ErrNotSupport
-		}
+	}
+	if err != nil {
+		return nil, err
 	}
 	if p.statistic {
 		pc = statistic.NewUDPTracker(pc, statistic.DefaultManager, currentMeta, nil, 0, 0, false)
diff --git a/dns/util.go b/dns/util.go
index 9df4482b..bfd2e9ed 100644
--- a/dns/util.go
+++ b/dns/util.go
@@ -170,15 +170,15 @@ func getDialHandler(r *Resolver, proxyAdapter C.ProxyAdapter, proxyName string,
 					Host:    host,
 					DstPort: port,
 				}
-				if proxyAdapter.IsL3Protocol(metadata) {
-					dstIP, err := resolver.ResolveIPWithResolver(ctx, host, r)
-					if err != nil {
-						return nil, err
-					}
-					metadata.Host = ""
-					metadata.DstIP = dstIP
-				}
 				if proxyAdapter != nil {
+					if proxyAdapter.IsL3Protocol(metadata) { // L3 proxy should resolve domain before to avoid loopback
+						dstIP, err := resolver.ResolveIPWithResolver(ctx, host, r)
+						if err != nil {
+							return nil, err
+						}
+						metadata.Host = ""
+						metadata.DstIP = dstIP
+					}
 					return proxyAdapter.DialContext(ctx, metadata, opts...)
 				}
 				opts = append(opts, dialer.WithResolver(r))