From a5d54884e0a281030ec9a4ba44384cf948a75c6c Mon Sep 17 00:00:00 2001
From: Dreamacro <8615343+Dreamacro@users.noreply.github.com>
Date: Sun, 1 Jan 2023 20:12:17 +0800
Subject: [PATCH] Feature: add `udp-fallback-match` option

---
 config/config.go         | 7 ++++++-
 hub/executor/executor.go | 4 +++-
 tunnel/tunnel.go         | 9 +++++++--
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/config/config.go b/config/config.go
index d906341..4bd651c 100644
--- a/config/config.go
+++ b/config/config.go
@@ -86,7 +86,9 @@ type Profile struct {
 }
 
 // Experimental config
-type Experimental struct{}
+type Experimental struct {
+	UDPFallbackMatch bool `yaml:"udp-fallback-match"`
+}
 
 // Config is clash config manager
 type Config struct {
@@ -250,6 +252,9 @@ func UnmarshalRawConfig(buf []byte) (*RawConfig, error) {
 		Profile: Profile{
 			StoreSelected: true,
 		},
+		Experimental: Experimental{
+			UDPFallbackMatch: true,
+		},
 	}
 
 	if err := yaml.Unmarshal(buf, rawCfg); err != nil {
diff --git a/hub/executor/executor.go b/hub/executor/executor.go
index a131f4b..8f94bc7 100644
--- a/hub/executor/executor.go
+++ b/hub/executor/executor.go
@@ -104,7 +104,9 @@ func GetGeneral() *config.General {
 	return general
 }
 
-func updateExperimental(c *config.Config) {}
+func updateExperimental(c *config.Config) {
+	tunnel.UDPFallbackMatch.Store(c.Experimental.UDPFallbackMatch)
+}
 
 func updateDNS(c *config.DNS) {
 	if !c.Enable {
diff --git a/tunnel/tunnel.go b/tunnel/tunnel.go
index bf09f23..20e03fd 100644
--- a/tunnel/tunnel.go
+++ b/tunnel/tunnel.go
@@ -19,6 +19,8 @@ import (
 	icontext "github.com/Dreamacro/clash/context"
 	"github.com/Dreamacro/clash/log"
 	"github.com/Dreamacro/clash/tunnel/statistic"
+
+	"go.uber.org/atomic"
 )
 
 var (
@@ -35,6 +37,9 @@ var (
 
 	// default timeout for UDP session
 	udpTimeout = 60 * time.Second
+
+	// experimental feature
+	UDPFallbackMatch = atomic.NewBool(false)
 )
 
 func init() {
@@ -407,8 +412,8 @@ func match(metadata *C.Metadata) (C.Proxy, C.Rule, error) {
 				continue
 			}
 
-			if metadata.NetWork == C.UDP && !adapter.SupportUDP() {
-				log.Debugln("%s UDP is not supported", adapter.Name())
+			if metadata.NetWork == C.UDP && !adapter.SupportUDP() && UDPFallbackMatch.Load() {
+				log.Debugln("[Matcher] %s UDP is not supported, skip match", adapter.Name())
 				continue
 			}
 			return adapter, rule, nil