From 775ec284853932ac328d09e47a603777194fc693 Mon Sep 17 00:00:00 2001
From: anlicheng <244108715@qq.com>
Date: Thu, 15 Jan 2026 15:11:48 +0800
Subject: [PATCH] fix

---
 apps/sdlan/include/sdlan.hrl     |  4 ++++
 apps/sdlan/src/sdlan_network.erl | 31 +++++++++++++++++++++++++------
 apps/sdlan/src/sdlan_stun.erl    | 17 +++++++++++++++++
 3 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/apps/sdlan/include/sdlan.hrl b/apps/sdlan/include/sdlan.hrl
index 0f2e6c5..87e350f 100644
--- a/apps/sdlan/include/sdlan.hrl
+++ b/apps/sdlan/include/sdlan.hrl
@@ -77,6 +77,10 @@
 %% 数据转发
 -define(PACKET_STUN_DATA, 16#FF).
 
+%% arp查询 request -> response
+-define(PACKET_ARP_REQUEST, 16#a0).
+-define(PACKET_ARP_RESPONSE, 16#a1).
+
 -record(id_generator, {
     tab :: atom(),
     increment_id = 0 :: integer()
diff --git a/apps/sdlan/src/sdlan_network.erl b/apps/sdlan/src/sdlan_network.erl
index c2a0c70..5c72ee2 100644
--- a/apps/sdlan/src/sdlan_network.erl
+++ b/apps/sdlan/src/sdlan_network.erl
@@ -333,7 +333,6 @@ handle_cast({forward, Sock, SrcMac, DstMac, Packet}, State = #state{network_id =
     end;
 
 %% 网络数据转发, ip广播或组播, 不限流
-%% TODO 需要处理arp请求，arp请求就不要广播出去了，network是知道目标的ip信息的
 handle_cast({forward, Sock, SrcMac, DstMac, Packet}, State = #state{network_id = NetworkId, endpoints = Endpoints, forward_bytes = ForwardBytes})
     when is_map_key(SrcMac, Endpoints) ->
     %% 广播地址和组播地址，需要转发到整个网络
@@ -345,10 +344,14 @@ handle_cast({forward, Sock, SrcMac, DstMac, Packet}, State = #state{network_id =
                     TargetIp = arp_packet:target_ip(ArpRequestPkt),
                     %% 通过ip查找到对应的Endpoint
 
-                    TargetMac = <<>>,
-                    ArpResponse = arp_packet:marshal(arp_packet:arp_response(ArpRequestPkt, TargetMac, TargetIp)),
-                    #endpoint{hole = #hole{peer = {NatIp, NatPort}}} = maps:get(SrcMac, Endpoints),
-                    gen_udp:send(Sock, NatIp, NatPort, ArpResponse);
+                    case search_endpoint(fun(#endpoint{ip = Ip0}) -> TargetIp =:= Ip0 end, Endpoints) of
+                        {ok, TargetMac, _} ->
+                            ArpResponse = arp_packet:marshal(arp_packet:arp_response(ArpRequestPkt, TargetMac, TargetIp)),
+                            #endpoint{hole = #hole{peer = {NatIp, NatPort}}} = maps:get(SrcMac, Endpoints),
+                            gen_udp:send(Sock, NatIp, NatPort, ArpResponse);
+                        error ->
+                            ok
+                    end;
 
                 error ->
                     PacketBytes = byte_size(Packet),
@@ -582,4 +585,20 @@ format_endpoint({Mac, #endpoint{client_id = ClientId, ip = Ip, hole = Hole, v6_i
         ip => sdlan_ipaddr:int_to_ipv4(Ip),
         hole_map => HoleMap,
         v6_info => V6InfoMap
-    }.
\ No newline at end of file
+    }.
+
+-spec search_endpoint(F :: fun((term(), term()) -> boolean()), Endpoints :: map()) -> error | {ok, Key :: any(), Val :: any()}.
+search_endpoint(F, Endpoints) when is_function(F, 1), is_map(Endpoints) ->
+    search_endpoint0(F, maps:iterator(Endpoints)).
+search_endpoint0(F, Iter) when is_function(F, 1) ->
+    case maps:next(Iter) of
+        {Key, Value, NextIter} ->
+            case F(Key, Value) of
+                true ->
+                    {ok, Key, Value};
+                false ->
+                    search_endpoint0(F, NextIter)
+            end;
+        'none' ->
+            error
+    end.
\ No newline at end of file
diff --git a/apps/sdlan/src/sdlan_stun.erl b/apps/sdlan/src/sdlan_stun.erl
index f45da2d..3d7d6d2 100644
--- a/apps/sdlan/src/sdlan_stun.erl
+++ b/apps/sdlan/src/sdlan_stun.erl
@@ -165,6 +165,23 @@ handle_info({udp, _, _Ip, _Port, <<?PACKET_STUN_DATA, Body/binary>>}, State = #s
 
     {noreply, State};
 
+handle_info({udp, _, _Ip, _Port, <<?PACKET_ARP_REQUEST, Body/binary>>}, State = #state{socket = Sock}) ->
+    Data = #sdl_data{network_id = NetworkId, src_mac = SrcMac, dst_mac = DstMac, ttl = TTL} = sdlan_pb:decode_msg(Body, sdl_data),
+
+    lager:debug("[sdlan_stun] stun data, src_mac: ~p, dst_mac: ~p", [sdlan_util:format_mac(SrcMac), sdlan_util:format_mac(DstMac)]),
+
+    %% 重新打包数据ttl需要减1
+    case sdlan_network:get_pid(NetworkId) of
+        NetworkPid when is_pid(NetworkPid) ->
+            NData = sdlan_pb:encode_msg(Data#sdl_data{ttl = TTL - 1, is_p2p = false}),
+            sdlan_network:forward(NetworkPid, Sock, SrcMac, DstMac, <<?PACKET_STUN_DATA, NData/binary>>);
+        _ ->
+            ok
+    end,
+
+    {noreply, State};
+
+
 handle_info(Info, State) ->
     lager:error("[sdlan_stun] get a unknown message: ~p, channel will closed", [Info]),
     {noreply, State}.