From 3880c3c1be0f97f0f2985329f45a3c720ba58cd7 Mon Sep 17 00:00:00 2001
From: wwqgtxx <wwqgtxx@gmail.com>
Date: Thu, 24 Nov 2022 12:32:35 +0800
Subject: [PATCH] chore: add retry in tunnel dial

---
 go.mod           |  1 +
 go.sum           |  2 ++
 tunnel/tunnel.go | 42 ++++++++++++++++++++++++++++++++++++++----
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/go.mod b/go.mod
index 140b1be0..feef8810 100644
--- a/go.mod
+++ b/go.mod
@@ -16,6 +16,7 @@ require (
 	github.com/gorilla/websocket v1.5.0
 	github.com/hashicorp/golang-lru v0.5.4
 	github.com/insomniacslk/dhcp v0.0.0-20221001123530-5308ebe5334c
+	github.com/jpillora/backoff v1.0.0
 	github.com/lucas-clemente/quic-go v0.29.1
 	github.com/lunixbochs/struc v0.0.0-20200707160740-784aaebc1d40
 	github.com/mdlayher/netlink v1.1.1
diff --git a/go.sum b/go.sum
index e85ef9b1..fe36da98 100644
--- a/go.sum
+++ b/go.sum
@@ -62,6 +62,8 @@ github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714/go.mod h1:2Go
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/insomniacslk/dhcp v0.0.0-20221001123530-5308ebe5334c h1:OCFM4+DXTWfNlyeoddrTwdup/ztkGSyAMR2UGcPckNQ=
 github.com/insomniacslk/dhcp v0.0.0-20221001123530-5308ebe5334c/go.mod h1:h+MxyHxRg9NH3terB1nfRIUaQEcI0XOVkdR9LNBlp8E=
+github.com/jpillora/backoff v1.0.0 h1:uvFg412JmmHBHw7iwprIxkPMI+sGQ4kzOWsMeHnm2EA=
+github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
 github.com/jsimonetti/rtnetlink v0.0.0-20190606172950-9527aa82566a/go.mod h1:Oz+70psSo5OFh8DBl0Zv2ACw7Esh6pPUphlvZG9x7uw=
 github.com/jsimonetti/rtnetlink v0.0.0-20200117123717-f846d4f6c1f4/go.mod h1:WGuG/smIU4J/54PblvSbh+xvCZmpJnFgr3ds6Z55XMQ=
 github.com/jsimonetti/rtnetlink v0.0.0-20201009170750-9c6f07d100c1/go.mod h1:hqoO/u39cqLeBLebZ8fWdE96O7FxrAsRYhnVOdgHxok=
diff --git a/tunnel/tunnel.go b/tunnel/tunnel.go
index 2e38da40..c602a0be 100644
--- a/tunnel/tunnel.go
+++ b/tunnel/tunnel.go
@@ -11,6 +11,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/jpillora/backoff"
+
 	"github.com/Dreamacro/clash/adapter/inbound"
 	"github.com/Dreamacro/clash/component/nat"
 	P "github.com/Dreamacro/clash/component/process"
@@ -273,8 +275,9 @@ func handleUDPConn(packet *inbound.PacketAdapter) {
 
 		ctx, cancel := context.WithTimeout(context.Background(), C.DefaultUDPTimeout)
 		defer cancel()
-		rawPc, err := proxy.ListenPacketContext(ctx, metadata.Pure())
-		if err != nil {
+		rawPc, err := retry(ctx, func(ctx context.Context) (C.PacketConn, error) {
+			return proxy.ListenPacketContext(ctx, metadata.Pure())
+		}, func(err error) {
 			if rule == nil {
 				log.Warnln(
 					"[UDP] dial %s %s --> %s error: %s",
@@ -286,6 +289,8 @@ func handleUDPConn(packet *inbound.PacketAdapter) {
 			} else {
 				log.Warnln("[UDP] dial %s (match %s/%s) %s --> %s error: %s", proxy.Name(), rule.RuleType().String(), rule.Payload(), metadata.SourceAddress(), metadata.RemoteAddress(), err.Error())
 			}
+		})
+		if err != nil {
 			return
 		}
 		pCtx.InjectPacketConn(rawPc)
@@ -354,8 +359,9 @@ func handleTCPConn(connCtx C.ConnContext) {
 
 	ctx, cancel := context.WithTimeout(context.Background(), C.DefaultTCPTimeout)
 	defer cancel()
-	remoteConn, err := proxy.DialContext(ctx, dialMetadata)
-	if err != nil {
+	remoteConn, err := retry(ctx, func(ctx context.Context) (C.Conn, error) {
+		return proxy.DialContext(ctx, dialMetadata)
+	}, func(err error) {
 		if rule == nil {
 			log.Warnln(
 				"[TCP] dial %s %s --> %s error: %s",
@@ -367,6 +373,8 @@ func handleTCPConn(connCtx C.ConnContext) {
 		} else {
 			log.Warnln("[TCP] dial %s (match %s/%s) %s --> %s error: %s", proxy.Name(), rule.RuleType().String(), rule.Payload(), metadata.SourceAddress(), metadata.RemoteAddress(), err.Error())
 		}
+	})
+	if err != nil {
 		return
 	}
 
@@ -473,3 +481,29 @@ func match(metadata *C.Metadata) (C.Proxy, C.Rule, error) {
 
 	return proxies["DIRECT"], nil, nil
 }
+
+func retry[T any](ctx context.Context, ft func(context.Context) (T, error), fe func(err error)) (t T, err error) {
+	b := &backoff.Backoff{
+		Min:    10 * time.Millisecond,
+		Max:    1 * time.Second,
+		Factor: 2,
+		Jitter: true,
+	}
+	for i := 0; i < 10; i++ {
+		t, err = ft(ctx)
+		if err != nil {
+			if fe != nil {
+				fe(err)
+			}
+			select {
+			case <-time.After(b.Duration()):
+				continue
+			case <-ctx.Done():
+				return
+			}
+		} else {
+			break
+		}
+	}
+	return
+}