From 3373b62b02282982d4646548e36383ea45d33615 Mon Sep 17 00:00:00 2001
From: wwqgtxx <wwqgtxx@gmail.com>
Date: Thu, 3 Nov 2022 12:58:21 +0800
Subject: [PATCH] fix: try to support android hotspot when using tun

---
 listener/sing_tun/server.go            |  5 ++++-
 listener/sing_tun/server_android.go    | 26 ++++++++++++++++++++++++++
 listener/sing_tun/server_notandroid.go |  1 +
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/listener/sing_tun/server.go b/listener/sing_tun/server.go
index f1327b33..83d38e28 100644
--- a/listener/sing_tun/server.go
+++ b/listener/sing_tun/server.go
@@ -203,11 +203,14 @@ func New(options config.Tun, tcpIn chan<- C.ConnContext, udpIn chan<- *inbound.P
 	if err != nil {
 		return
 	}
-	err = l.tunStack.Start()
 
+	err = l.tunStack.Start()
 	if err != nil {
 		return
 	}
+
+	l.openAndroidHotspot(tunOptions)
+
 	log.Infoln("[TUN] Tun adapter listening at: %s(%s,%s), mtu: %d, auto route: %v, ip stack: %s",
 		tunName, tunOptions.Inet4Address, tunOptions.Inet6Address, tunMTU, options.AutoRoute, options.Stack)
 	return
diff --git a/listener/sing_tun/server_android.go b/listener/sing_tun/server_android.go
index e9d36f66..f8befe6e 100644
--- a/listener/sing_tun/server_android.go
+++ b/listener/sing_tun/server_android.go
@@ -1,7 +1,11 @@
 package sing_tun
 
 import (
+	"github.com/Dreamacro/clash/log"
+	"github.com/sagernet/netlink"
 	tun "github.com/sagernet/sing-tun"
+	"golang.org/x/sys/unix"
+	"runtime"
 )
 
 func (l *Listener) buildAndroidRules(tunOptions *tun.Options) error {
@@ -21,3 +25,25 @@ func (l *Listener) buildAndroidRules(tunOptions *tun.Options) error {
 func (h *ListenerHandler) OnPackagesUpdated(packages int, sharedUsers int) {
 	return
 }
+
+func (l *Listener) openAndroidHotspot(tunOptions tun.Options) {
+	if runtime.GOOS == "android" && tunOptions.AutoRoute {
+		priority := 9000
+		if len(tunOptions.ExcludedRanges()) > 0 {
+			priority++
+		}
+		if tunOptions.InterfaceMonitor.AndroidVPNEnabled() {
+			priority++
+		}
+		it := netlink.NewRule()
+		it.Priority = priority
+		it.IifName = tunOptions.Name
+		it.Table = 254 //main
+		it.Family = unix.AF_INET
+		it.SuppressPrefixlen = 0
+		err := netlink.RuleAdd(it)
+		if err != nil {
+			log.Warnln("[TUN] add AndroidHotspot rule error")
+		}
+	}
+}
diff --git a/listener/sing_tun/server_notandroid.go b/listener/sing_tun/server_notandroid.go
index f621c71e..6db98989 100644
--- a/listener/sing_tun/server_notandroid.go
+++ b/listener/sing_tun/server_notandroid.go
@@ -9,3 +9,4 @@ import (
 func (l *Listener) buildAndroidRules(tunOptions *tun.Options) error {
 	return nil
 }
+func (l *Listener) openAndroidHotspot(tunOptions tun.Options) {}