chore: support longest-prefix matches in local interface finding

component/iface/iface.go

@@ -7,6 +7,8 @@ import (
 	"time"
 
 	"github.com/metacubex/mihomo/common/singledo"
+
+	"github.com/metacubex/bart"
 )
 
 type Interface struct {
@@ -23,16 +25,23 @@ var (
 	ErrAddrNotFound  = errors.New("addr not found")
 )
 
-var interfaces = singledo.NewSingle[map[string]*Interface](time.Second * 20)
+type ifaceCache struct {
+	ifMap   map[string]*Interface
+	ifTable bart.Table[*Interface]
+}
 
-func Interfaces() (map[string]*Interface, error) {
-	value, err, _ := interfaces.Do(func() (map[string]*Interface, error) {
+var caches = singledo.NewSingle[*ifaceCache](time.Second * 20)
+
+func getCache() (*ifaceCache, error) {
+	value, err, _ := caches.Do(func() (*ifaceCache, error) {
 		ifaces, err := net.Interfaces()
 		if err != nil {
 			return nil, err
 		}
 
-		r := map[string]*Interface{}
+		cache := &ifaceCache{
+			ifMap: make(map[string]*Interface),
+		}
 
 		for _, iface := range ifaces {
 			addrs, err := iface.Addrs()
@@ -61,7 +70,7 @@ func Interfaces() (map[string]*Interface, error) {
 				}
 			}
 
-			r[iface.Name] = &Interface{
+			ifaceObj := &Interface{
 				Index:        iface.Index,
 				MTU:          iface.MTU,
 				Name:         iface.Name,
@@ -69,13 +78,26 @@ func Interfaces() (map[string]*Interface, error) {
 				Flags:        iface.Flags,
 				Addresses:    ipNets,
 			}
+			cache.ifMap[iface.Name] = ifaceObj
+
+			for _, prefix := range ipNets {
+				cache.ifTable.Insert(prefix, ifaceObj)
+			}
 		}
 
-		return r, nil
+		return cache, nil
 	})
 	return value, err
 }
 
+func Interfaces() (map[string]*Interface, error) {
+	cache, err := getCache()
+	if err != nil {
+		return nil, err
+	}
+	return cache.ifMap, nil
+}
+
 func ResolveInterface(name string) (*Interface, error) {
 	ifaces, err := Interfaces()
 	if err != nil {
@@ -90,23 +112,29 @@ func ResolveInterface(name string) (*Interface, error) {
 	return iface, nil
 }
 
-func IsLocalIp(ip netip.Addr) (bool, error) {
-	ifaces, err := Interfaces()
+func ResolveInterfaceByAddr(addr netip.Addr) (*Interface, error) {
+	cache, err := getCache()
+	if err != nil {
+		return nil, err
+	}
+	iface, ok := cache.ifTable.Lookup(addr)
+	if !ok {
+		return nil, ErrIfaceNotFound
+	}
+
+	return iface, nil
+}
+
+func IsLocalIp(addr netip.Addr) (bool, error) {
+	cache, err := getCache()
 	if err != nil {
 		return false, err
 	}
-	for _, iface := range ifaces {
-		for _, addr := range iface.Addresses {
-			if addr.Contains(ip) {
-				return true, nil
-			}
-		}
-	}
-	return false, nil
+	return cache.ifTable.Contains(addr), nil
 }
 
 func FlushCache() {
-	interfaces.Reset()
+	caches.Reset()
 }
 
 func (iface *Interface) PickIPv4Addr(destination netip.Addr) (netip.Prefix, error) {