From 9e3bf14b1aa17027e8b231fe3d01cb0891d72ad3 Mon Sep 17 00:00:00 2001
From: wwqgtxx <wwqgtxx@gmail.com>
Date: Fri, 23 May 2025 20:59:02 +0800
Subject: [PATCH] chore: handle two interfaces have the same prefix but
 different address

---
 component/iface/iface.go | 21 +++++++++++++++------
 go.mod                   |  2 +-
 go.sum                   |  4 ++--
 3 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/component/iface/iface.go b/component/iface/iface.go
index 92e0ccf3..ddb779aa 100644
--- a/component/iface/iface.go
+++ b/component/iface/iface.go
@@ -26,8 +26,9 @@ var (
 )
 
 type ifaceCache struct {
-	ifMap   map[string]*Interface
-	ifTable bart.Table[*Interface]
+	ifMapByName map[string]*Interface
+	ifMapByAddr map[netip.Addr]*Interface
+	ifTable     bart.Table[*Interface]
 }
 
 var caches = singledo.NewSingle[*ifaceCache](time.Second * 20)
@@ -40,7 +41,8 @@ func getCache() (*ifaceCache, error) {
 		}
 
 		cache := &ifaceCache{
-			ifMap: make(map[string]*Interface),
+			ifMapByName: make(map[string]*Interface),
+			ifMapByAddr: make(map[netip.Addr]*Interface),
 		}
 
 		for _, iface := range ifaces {
@@ -78,12 +80,13 @@ func getCache() (*ifaceCache, error) {
 				Flags:        iface.Flags,
 				Addresses:    ipNets,
 			}
-			cache.ifMap[iface.Name] = ifaceObj
+			cache.ifMapByName[iface.Name] = ifaceObj
 
 			if iface.Flags&net.FlagUp == 0 {
 				continue // interface down
 			}
 			for _, prefix := range ipNets {
+				cache.ifMapByAddr[prefix.Addr()] = ifaceObj
 				cache.ifTable.Insert(prefix, ifaceObj)
 			}
 		}
@@ -98,7 +101,7 @@ func Interfaces() (map[string]*Interface, error) {
 	if err != nil {
 		return nil, err
 	}
-	return cache.ifMap, nil
+	return cache.ifMapByName, nil
 }
 
 func ResolveInterface(name string) (*Interface, error) {
@@ -120,6 +123,11 @@ func ResolveInterfaceByAddr(addr netip.Addr) (*Interface, error) {
 	if err != nil {
 		return nil, err
 	}
+	// maybe two interfaces have the same prefix but different address
+	// so direct check address equal before do a route lookup (longest prefix match)
+	if iface, ok := cache.ifMapByAddr[addr]; ok {
+		return iface, nil
+	}
 	iface, ok := cache.ifTable.Lookup(addr)
 	if !ok {
 		return nil, ErrIfaceNotFound
@@ -133,7 +141,8 @@ func IsLocalIp(addr netip.Addr) (bool, error) {
 	if err != nil {
 		return false, err
 	}
-	return cache.ifTable.Contains(addr), nil
+	_, ok := cache.ifMapByAddr[addr]
+	return ok, nil
 }
 
 func FlushCache() {
diff --git a/go.mod b/go.mod
index cffcde9e..cf9ce2c7 100644
--- a/go.mod
+++ b/go.mod
@@ -25,7 +25,7 @@ require (
 	github.com/metacubex/gopacket v1.1.20-0.20230608035415-7e2f98a3e759
 	github.com/metacubex/quic-go v0.52.1-0.20250522021943-aef454b9e639
 	github.com/metacubex/randv2 v0.2.0
-	github.com/metacubex/sing v0.5.3-0.20250504031621-1f99e54c15b7
+	github.com/metacubex/sing v0.5.3
 	github.com/metacubex/sing-mux v0.3.2
 	github.com/metacubex/sing-quic v0.0.0-20250523120938-f1a248e5ec7f
 	github.com/metacubex/sing-shadowsocks v0.2.9
diff --git a/go.sum b/go.sum
index cd8787ee..6b0c9373 100644
--- a/go.sum
+++ b/go.sum
@@ -116,8 +116,8 @@ github.com/metacubex/quic-go v0.52.1-0.20250522021943-aef454b9e639/go.mod h1:Kc6
 github.com/metacubex/randv2 v0.2.0 h1:uP38uBvV2SxYfLj53kuvAjbND4RUDfFJjwr4UigMiLs=
 github.com/metacubex/randv2 v0.2.0/go.mod h1:kFi2SzrQ5WuneuoLLCMkABtiBu6VRrMrWFqSPyj2cxY=
 github.com/metacubex/sing v0.5.2/go.mod h1:ypf0mjwlZm0sKdQSY+yQvmsbWa0hNPtkeqyRMGgoN+w=
-github.com/metacubex/sing v0.5.3-0.20250504031621-1f99e54c15b7 h1:m4nSxvw46JEgxMzzmnXams+ebwabcry4Ydep/zNiesQ=
-github.com/metacubex/sing v0.5.3-0.20250504031621-1f99e54c15b7/go.mod h1:ypf0mjwlZm0sKdQSY+yQvmsbWa0hNPtkeqyRMGgoN+w=
+github.com/metacubex/sing v0.5.3 h1:QWdN16WFKMk06x4nzkc8SvZ7y2x+TLQrpkPoHs+WSVM=
+github.com/metacubex/sing v0.5.3/go.mod h1:ypf0mjwlZm0sKdQSY+yQvmsbWa0hNPtkeqyRMGgoN+w=
 github.com/metacubex/sing-mux v0.3.2 h1:nJv52pyRivHcaZJKk2JgxpaVvj1GAXG81scSa9N7ncw=
 github.com/metacubex/sing-mux v0.3.2/go.mod h1:3rt1soewn0O6j89GCLmwAQFsq257u0jf2zQSPhTL3Bw=
 github.com/metacubex/sing-quic v0.0.0-20250523120938-f1a248e5ec7f h1:mP3vIm+9hRFI0C0Vl3pE0NESF/L85FDbuB0tGgUii6I=