refactor: new way to get interface change even for linux

go.mod

@@ -16,6 +16,7 @@ require (
 	github.com/oschwald/geoip2-golang v1.7.0
 	github.com/sirupsen/logrus v1.8.1
 	github.com/stretchr/testify v1.7.1
+	github.com/vishvananda/netlink v1.0.1-0.20190930145447-2ec5bdc52b86
 	github.com/xtls/go v0.0.0-20210920065950-d4af136d3672
 	go.etcd.io/bbolt v1.3.6
 	go.uber.org/atomic v1.9.0
@@ -48,6 +49,7 @@ require (
 	github.com/oschwald/maxminddb-golang v1.9.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/u-root/uio v0.0.0-20220204230159-dac05f7d2cb4 // indirect
+	github.com/vishvananda/netns v0.0.0-20211101163701-50045581ed74 // indirect
 	golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 // indirect
 	golang.org/x/text v0.3.8-0.20220124021120-d1c84af989ab // indirect
 	golang.org/x/tools v0.1.10 // indirect

go.sum

@@ -202,6 +202,10 @@ github.com/u-root/uio v0.0.0-20220204230159-dac05f7d2cb4 h1:hl6sK6aFgTLISijk6xIz
 github.com/u-root/uio v0.0.0-20220204230159-dac05f7d2cb4/go.mod h1:LpEX5FO/cB+WF4TYGY1V5qktpaZLkKkSegbr0V4eYXA=
 github.com/viant/assertly v0.4.8/go.mod h1:aGifi++jvCrUaklKEKT0BU95igDNaqkvz+49uaYMPRU=
 github.com/viant/toolbox v0.24.0/go.mod h1:OxMCG57V0PXuIP2HNQrtJf2CjqdmbrOx5EkMILuUhzM=
+github.com/vishvananda/netlink v1.0.1-0.20190930145447-2ec5bdc52b86 h1:7SWt9pGCMaw+N1ZhRsaLKaYNviFhxambdoaoYlDqz1w=
+github.com/vishvananda/netlink v1.0.1-0.20190930145447-2ec5bdc52b86/go.mod h1:+SR5DhBJrl6ZM7CoCKvpw5BKroDKQ+PJqOg65H/2ktk=
+github.com/vishvananda/netns v0.0.0-20211101163701-50045581ed74 h1:gga7acRE695APm9hlsSMoOoE65U4/TcqNj90mc69Rlg=
+github.com/vishvananda/netns v0.0.0-20211101163701-50045581ed74/go.mod h1:DD4vA1DwXk04H54A1oHXtwZmA0grkVMdPxx/VGLCah0=
 github.com/xtls/go v0.0.0-20210920065950-d4af136d3672 h1:4mkzGhKqt3JO1BWYjtD3iRFyAx4ow67hmSqOcGjuxqQ=
 github.com/xtls/go v0.0.0-20210920065950-d4af136d3672/go.mod h1:YGGVbz9cOxyKFUmhW7LGaLZaMA0cPlHJinvAmVxEMSU=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
@@ -289,6 +293,7 @@ golang.org/x/sys v0.0.0-20191008105621-543471e840be/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200202164722-d101bd2416d5/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200217220822-9197077df867/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200519105757-fe76b779f299/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

listener/tun/ipstack/commons/auto_linux.go

@@ -0,0 +1,90 @@
+package commons
+
+import (
+	"github.com/Dreamacro/clash/component/dialer"
+	"github.com/Dreamacro/clash/component/iface"
+	"github.com/Dreamacro/clash/log"
+	"github.com/vishvananda/netlink"
+	"go.uber.org/atomic"
+	"time"
+)
+
+var (
+	monitorStarted = atomic.NewBool(false)
+	monitorStop    = make(chan struct{}, 2)
+)
+
+func StartDefaultInterfaceChangeMonitor() {
+	go func() {
+		if monitorStarted.Load() {
+			return
+		}
+		monitorStarted.Store(true)
+
+		done := make(chan struct{})
+		ch := make(chan netlink.RouteUpdate, 2)
+		err := netlink.RouteSubscribe(ch, done)
+		if err != nil {
+			log.Warnln("[TUN] auto detect interface fail: %s", err)
+			return
+		}
+		log.Debugln("[TUN] start auto detect interface monitor")
+		defer func() {
+			close(done)
+			monitorStarted.Store(false)
+			log.Debugln("[TUN] stop auto detect interface monitor")
+		}()
+
+		select {
+		case <-monitorStop:
+		default:
+		}
+
+		for {
+			select {
+			case <-monitorStop:
+				return
+			case <-ch:
+			}
+
+			interfaceName, err := GetAutoDetectInterface()
+			if err != nil {
+				t := time.NewTicker(2 * time.Second)
+				for {
+					select {
+					case ch <- <-ch:
+						break
+					case <-t.C:
+						interfaceName, err = GetAutoDetectInterface()
+						if err != nil {
+							continue
+						}
+					}
+					break
+				}
+				t.Stop()
+			}
+
+			if err != nil {
+				log.Debugln("[TUN] detect interface: %s", err)
+				continue
+			}
+
+			old := dialer.DefaultInterface.Load()
+			if interfaceName == old {
+				continue
+			}
+
+			dialer.DefaultInterface.Store(interfaceName)
+			iface.FlushCache()
+
+			log.Warnln("[TUN] default interface changed by monitor, %s => %s", old, interfaceName)
+		}
+	}()
+}
+
+func StopDefaultInterfaceChangeMonitor() {
+	if monitorStarted.Load() {
+		monitorStop <- struct{}{}
+	}
+}

listener/tun/ipstack/commons/auto_others.go

@@ -0,0 +1,67 @@
+//go:build !linux
+
+package commons
+
+import (
+	"github.com/Dreamacro/clash/component/dialer"
+	"github.com/Dreamacro/clash/component/iface"
+	"github.com/Dreamacro/clash/log"
+	"go.uber.org/atomic"
+	"time"
+)
+
+var (
+	monitorDuration = 3 * time.Second
+	monitorStarted  = atomic.NewBool(false)
+	monitorStop     = make(chan struct{}, 2)
+)
+
+func StartDefaultInterfaceChangeMonitor() {
+	go func() {
+		if monitorStarted.Load() {
+			return
+		}
+		monitorStarted.Store(true)
+		t := time.NewTicker(monitorDuration)
+		log.Debugln("[TUN] start auto detect interface monitor")
+		defer func() {
+			monitorStarted.Store(false)
+			t.Stop()
+			log.Debugln("[TUN] stop auto detect interface monitor")
+		}()
+
+		select {
+		case <-monitorStop:
+		default:
+		}
+
+		for {
+			select {
+			case <-t.C:
+				interfaceName, err := GetAutoDetectInterface()
+				if err != nil {
+					log.Warnln("[TUN] default interface monitor err: %v", err)
+					continue
+				}
+
+				old := dialer.DefaultInterface.Load()
+				if interfaceName == old {
+					continue
+				}
+
+				dialer.DefaultInterface.Store(interfaceName)
+				iface.FlushCache()
+
+				log.Warnln("[TUN] default interface changed by monitor, %s => %s", old, interfaceName)
+			case <-monitorStop:
+				break
+			}
+		}
+	}()
+}
+
+func StopDefaultInterfaceChangeMonitor() {
+	if monitorStarted.Load() {
+		monitorStop <- struct{}{}
+	}
+}

listener/tun/ipstack/commons/router.go

@@ -2,21 +2,13 @@ package commons
 
 import (
 	"fmt"
-	"github.com/Dreamacro/clash/component/dialer"
-	"github.com/Dreamacro/clash/component/iface"
 	"github.com/Dreamacro/clash/log"
 	"net"
-	"sync"
 	"time"
 )
 
 var (
 	defaultRoutes = []string{"1.0.0.0/8", "2.0.0.0/7", "4.0.0.0/6", "8.0.0.0/5", "16.0.0.0/4", "32.0.0.0/3", "64.0.0.0/2", "128.0.0.0/1"}
-
-	monitorDuration = 3 * time.Second
-	monitorStarted  = false
-	monitorStop     = make(chan struct{}, 2)
-	monitorMux      sync.Mutex
 )
 
 func ipv4MaskString(bits int) string {
@@ -28,59 +20,6 @@ func ipv4MaskString(bits int) string {
 	return fmt.Sprintf("%d.%d.%d.%d", m[0], m[1], m[2], m[3])
 }
 
-func StartDefaultInterfaceChangeMonitor() {
-	go func() {
-		monitorMux.Lock()
-		if monitorStarted {
-			monitorMux.Unlock()
-			return
-		}
-		monitorStarted = true
-		monitorMux.Unlock()
-
-		select {
-		case <-monitorStop:
-		default:
-		}
-
-		t := time.NewTicker(monitorDuration)
-		defer t.Stop()
-
-		for {
-			select {
-			case <-t.C:
-				interfaceName, err := GetAutoDetectInterface()
-				if err != nil {
-					log.Warnln("[TUN] default interface monitor err: %v", err)
-					continue
-				}
-
-				old := dialer.DefaultInterface.Load()
-				if interfaceName == old {
-					continue
-				}
-
-				dialer.DefaultInterface.Store(interfaceName)
-				iface.FlushCache()
-
-				log.Warnln("[TUN] default interface changed by monitor, %s => %s", old, interfaceName)
-			case <-monitorStop:
-				break
-			}
-		}
-	}()
-}
-
-func StopDefaultInterfaceChangeMonitor() {
-	monitorMux.Lock()
-	defer monitorMux.Unlock()
-
-	if monitorStarted {
-		monitorStop <- struct{}{}
-		monitorStarted = false
-	}
-}
-
 func WaitForTunClose(deviceName string) {
 	t := time.NewTicker(600 * time.Millisecond)
 	defer t.Stop()

listener/tun/ipstack/commons/router_linux.go

@@ -10,7 +10,11 @@ import (
 )
 
 func GetAutoDetectInterface() (string, error) {
-	return cmd.ExecCmd("bash -c ip route show | grep 'default via' | awk -F ' ' 'NR==1{print $5}' | xargs echo -n")
+	execCmd, err := cmd.ExecCmd("bash -c ip route show | grep 'default via' | awk -F ' ' 'NR==1{print $5}' | xargs echo -n")
+	if execCmd == "" {
+		return "", fmt.Errorf("interface not found")
+	}
+	return execCmd, err
 }
 
 func ConfigInterfaceAddress(dev device.Device, addr netip.Prefix, forceMTU int, autoRoute bool) error {