Fix linux route

monitor_linux_default.go

@@ -0,0 +1,41 @@
+//go:build linux && !android
+
+package tun
+
+import (
+	E "github.com/sagernet/sing/common/exceptions"
+
+	"github.com/vishvananda/netlink"
+	"golang.org/x/sys/unix"
+)
+
+func (m *defaultInterfaceMonitor) checkUpdate() error {
+	routes, err := netlink.RouteListFiltered(netlink.FAMILY_ALL, &netlink.Route{Table: unix.RT_TABLE_MAIN}, netlink.RT_FILTER_TABLE)
+	if err != nil {
+		return err
+	}
+	for _, route := range routes {
+		if route.Dst != nil {
+			continue
+		}
+
+		var link netlink.Link
+		link, err = netlink.LinkByIndex(route.LinkIndex)
+		if err != nil {
+			return err
+		}
+
+		oldInterface := m.defaultInterfaceName
+		oldIndex := m.defaultInterfaceIndex
+
+		m.defaultInterfaceName = link.Attrs().Name
+		m.defaultInterfaceIndex = link.Attrs().Index
+
+		if oldInterface == m.defaultInterfaceName && oldIndex == m.defaultInterfaceIndex {
+			return nil
+		}
+		m.callback()
+		return nil
+	}
+	return E.New("no route to internet")
+}