From 2a678a7e03ff8b42b9621751ca6d0f8bdb4660a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=96=E7=95=8C?= <i@sekai.icu>
Date: Wed, 8 Jul 2026 19:19:07 +0800
Subject: [PATCH] Fix bridge MTU

---
 protocol/bridge/backend_darwin.go | 6 ------
 protocol/bridge/backend_linux.go  | 2 --
 protocol/bridge/packet.go         | 1 +
 protocol/bridge/packet_windows.go | 5 -----
 4 files changed, 1 insertion(+), 13 deletions(-)
 delete mode 100644 protocol/bridge/packet_windows.go

diff --git a/protocol/bridge/backend_darwin.go b/protocol/bridge/backend_darwin.go
index ae93311be..e4ad445b7 100644
--- a/protocol/bridge/backend_darwin.go
+++ b/protocol/bridge/backend_darwin.go
@@ -23,12 +23,6 @@ var (
 	bridgeInet6LocalBase = netip.MustParseAddr("2001:db8:1::1")
 )
 
-// The darwin forwarding path silently drops frames larger than the outgoing
-// interface MTU (no ICMP, no counter), and virtualized ingress interfaces
-// (vmnet LRO) deliver TCP frames coalesced far beyond their own 1500 MTU, so
-// the bridge tun must accept full-size IP packets.
-const bridgeTunMTU = 0xffff
-
 type backendDarwin struct {
 	backendBase
 
diff --git a/protocol/bridge/backend_linux.go b/protocol/bridge/backend_linux.go
index 3cd722751..734c6a5df 100644
--- a/protocol/bridge/backend_linux.go
+++ b/protocol/bridge/backend_linux.go
@@ -20,8 +20,6 @@ import (
 const (
 	defaultBridgeRuleIndex      = 100
 	defaultBridgeTableIndexBase = 2200
-
-	bridgeTunMTU = 1500
 )
 
 type backendLinux struct {
diff --git a/protocol/bridge/packet.go b/protocol/bridge/packet.go
index fec9c626b..f9e2f4159 100644
--- a/protocol/bridge/packet.go
+++ b/protocol/bridge/packet.go
@@ -13,6 +13,7 @@ import (
 )
 
 const (
+	bridgeTunMTU         = 0xffff
 	maxPacketLength      = 0xffff
 	bridgeMaxInstances   = 254
 	bridgeWriteBatchSize = 32
diff --git a/protocol/bridge/packet_windows.go b/protocol/bridge/packet_windows.go
deleted file mode 100644
index 35ac1cf5c..000000000
--- a/protocol/bridge/packet_windows.go
+++ /dev/null
@@ -1,5 +0,0 @@
-//go:build windows && (amd64 || 386)
-
-package bridge
-
-const bridgeTunMTU = 1500