fix Snapshot

Tun/Punchnet/Arp/ArpServer.swift

@@ -19,11 +19,13 @@ actor ArpServer {
     
     private var known_macs: [UInt32: ArpEntry] = [:]
     private let arpTTL: TimeInterval
+    nonisolated private let snapshotPublisher: SnapshotPublisher<ArpSnapshot>
     
     private var cleanupTask: Task<Void, Never>?
     
     init(arpTTL: TimeInterval = 300) {
         self.arpTTL = arpTTL
+        self.snapshotPublisher = SnapshotPublisher(initial: ArpSnapshot.empty())
     }
     
     func start() {
@@ -46,6 +48,7 @@ actor ArpServer {
         
         if entry.expireTime < Date().timeIntervalSince1970 {
             known_macs.removeValue(forKey: ip)
+            self.publishSnapshot()
             return nil
         }
         
@@ -55,19 +58,23 @@ actor ArpServer {
     func append(ip: UInt32, mac: Data) {
         let expireAt = Date().timeIntervalSince1970 + arpTTL
         self.known_macs[ip] = ArpEntry(mac: mac, expireTime: expireAt)
+        self.publishSnapshot()
     }
     
     func remove(ip: UInt32) {
         self.known_macs.removeValue(forKey: ip)
+        self.publishSnapshot()
     }
     
     func dropMacs(macs: [Data]) {
         self.known_macs = self.known_macs.filter { !macs.contains($0.value.mac) }
+        self.publishSnapshot()
     }
     
     func clear() {
         self.known_macs = [:]
         self.coolingDown = [:]
+        self.publishSnapshot()
     }
 
     func stop() {
@@ -95,12 +102,34 @@ actor ArpServer {
         if !targetMac.isEmpty {
             let expireAt = Date().timeIntervalSince1970 + arpTTL
             self.known_macs[targetIp] = ArpEntry(mac: targetMac, expireTime: expireAt)
+            self.publishSnapshot()
         }
     }
 
+    nonisolated func snapshot() -> ArpSnapshot {
+        return self.snapshotPublisher.current()
+    }
+    
     private func cleanup() {
         let now = Date()
         self.coolingDown = self.coolingDown.filter { $0.value > now }
+        let oldCount = self.known_macs.count
+        self.known_macs = self.known_macs.filter { $0.value.expireTime >= now.timeIntervalSince1970 }
+        if self.known_macs.count != oldCount {
+            self.publishSnapshot()
+        }
+    }
+
+    private func publishSnapshot() {
+        self.snapshotPublisher.publish(self.compileSnapshot())
+    }
+
+    private func compileSnapshot() -> ArpSnapshot {
+        let now = Date().timeIntervalSince1970
+        let entries = self.known_macs.compactMapValues { entry in
+            entry.expireTime >= now ? entry.mac : nil
+        }
+        return ArpSnapshot(entries: entries)
     }
     
     deinit {

Tun/Punchnet/Arp/ArpSnapshot.swift

@@ -0,0 +1,24 @@
+//
+//  ArpSnapshot.swift
+//  Tun
+//
+//  Created by Codex on 2026/5/20.
+//
+
+import Foundation
+
+final class ArpSnapshot: Snapshot {
+    private let entries: [UInt32: Data]
+
+    init(entries: [UInt32: Data]) {
+        self.entries = entries
+    }
+
+    func lookup(_ ip: UInt32) -> Data? {
+        return self.entries[ip]
+    }
+
+    static func empty() -> ArpSnapshot {
+        return ArpSnapshot(entries: [:])
+    }
+}

Tun/Punchnet/Outbound/PacketOutboundActor.swift

@@ -195,7 +195,7 @@ actor PacketOutboundActor {
             SDLLogger.log("[PacketOutboundActor] use exit_node: \(SDLUtil.int32ToIp(ip))", for: .trace)
         }
 
-        if let dstMac = await self.arpServer.query(ip: ip) {
+        if let dstMac = self.arpServer.snapshot().lookup(ip) {
             SDLLogger.log("[PacketOutboundActor] dstIp: \(SDLUtil.int32ToIp(ip)), dst_mac is: \(SDLUtil.formatMacAddress(mac: dstMac))", for: .trace)
             await self.routeLayerPacket(dstMac: dstMac, type: type, data: data)
         } else {

Tun/Punchnet/Policy/IdentitySnapshot.swift

@@ -4,8 +4,9 @@
 //
 //  Created by 安礼成 on 2026/2/5.
 //
+import Foundation
 
-final class IdentitySnapshot {
+final class IdentitySnapshot: Snapshot {
     typealias IdentityID = UInt32
     
     private let identityMap: [IdentityID: IdentityRuleMap]

Tun/Punchnet/Snapshot/Snapshot.swift

@@ -0,0 +1,10 @@
+//
+//  Snapshot.swift
+//  punchnet
+//
+//  Created by 安礼成 on 2026/5/20.
+//
+
+protocol Snapshot: AnyObject {
+    
+}

Tun/Punchnet/Snapshot/SnapshotPublisher.swift

@@ -6,21 +6,21 @@
 //
 import Atomics
 
-final class SnapshotPublisher<IdentitySnapshot: AnyObject> {
+final class SnapshotPublisher<S: Snapshot> {
-    private let atomic: ManagedAtomic<Unmanaged<IdentitySnapshot>>
+    private let atomic: ManagedAtomic<Unmanaged<S>>
     
-    init(initial snapshot: IdentitySnapshot) {
+    init(initial snapshot: S) {
         self.atomic = ManagedAtomic(.passRetained(snapshot))
     }
 
-    func publish(_ snapshot: IdentitySnapshot) {
+    func publish(_ snapshot: S) {
         let newRef = Unmanaged.passRetained(snapshot)
         let oldRef = atomic.exchange(newRef, ordering: .acquiring)
         oldRef.release()
     }
 
     @inline(__always)
-    func current() -> IdentitySnapshot {
+    func current() -> S {
         atomic.load(ordering: .relaxed).takeUnretainedValue()
     }