模块化,方便作为lib库

apps/dns_proxy/src/dns_cache.erl

@@ -41,9 +41,7 @@ insert(#dns_query{name = Qname, type = QType, class = QClass},
         true ->
             TTL = lists:min(TTLs),
             ExpireAt = os:system_time(second) + TTL,
-
             lager:debug("min ttl is: ~p, expire_at: ~p", [TTL, ExpireAt]),
-
             Key = {Qname, QType, QClass},
             Cache = #dns_cache{
                 key = Key,

apps/dns_proxy/src/dns_handler.erl

@@ -20,7 +20,7 @@
 
 %% gen_server callbacks
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
--export([handle/5, handle_ip_packet/5]).
+-export([handle_ip_packet/6]).
 
 -define(SERVER, ?MODULE).
 -define(RESOLVER_POOL, dns_resolver_pool).
@@ -38,11 +38,8 @@
 start_link() ->
     gen_server:start_link(?MODULE, [], []).
 
-handle_ip_packet(Pid, Sock, SrcIp, SrcPort, Packet) when is_pid(Pid) ->
+handle_ip_packet(Pid, Sock, SrcIp, SrcPort, Packet, InbuiltResolver) when is_pid(Pid) ->
-    gen_server:cast(Pid, {handle_ip_packet, Sock, SrcIp, SrcPort, Packet}).
+    gen_server:cast(Pid, {handle_ip_packet, Sock, SrcIp, SrcPort, Packet, InbuiltResolver}).
-
-handle(Pid, Sock, SrcIp, SrcPort, Packet) when is_pid(Pid) ->
-    gen_server:cast(Pid, {handle, Sock, SrcIp, SrcPort, Packet}).
 
 %%%===================================================================
 %%% gen_server callbacks
@@ -75,14 +72,15 @@ handle_call(_Request, _From, State = #state{}) ->
     {noreply, NewState :: #state{}} |
     {noreply, NewState :: #state{}, timeout() | hibernate} |
     {stop, Reason :: term(), NewState :: #state{}}).
-handle_cast({handle_ip_packet, Sock, SrcIp, SrcPort, IpPacket}, State) ->
+handle_cast({handle_ip_packet, Sock, SrcIp, SrcPort, IpPacket, InbuiltResolver}, State) ->
     {#ipv4{saddr = ReqSAddr, daddr = ReqDAddr, p = Protocol}, ReqIpPayload} = pkt:ipv4(IpPacket),
     case Protocol =:= ?UDP_PROTOCOL of
         true ->
             {#udp{sport = ReqSPort, dport = ReqDPort}, UdpPayload} = pkt:udp(ReqIpPayload),
-            case resolver(UdpPayload) of
+            case resolver(UdpPayload, InbuiltResolver) of
                 {ok, DnsResp} ->
                     RespIpPacket = build_ip_packet(ReqDAddr, ReqSAddr, ReqDPort, ReqSPort, DnsResp),
+                    lager:debug("[dns_handler] ip packet: ~p", [RespIpPacket]),
                     gen_udp:send(Sock, SrcIp, SrcPort, RespIpPacket);
                 {error, Reason} ->
                     lager:debug("[dns_handler] resolver get error: ~p", [Reason])
@@ -90,14 +88,6 @@ handle_cast({handle_ip_packet, Sock, SrcIp, SrcPort, IpPacket}, State) ->
         false ->
             lager:debug("[dns_handler] resolver invalid protocol: ~p", [Protocol])
     end,
-    {stop, normal, State};
-handle_cast({handle, Sock, SrcIp, SrcPort, Packet}, State) ->
-    case resolver(Packet) of
-        {ok, Resp} ->
-            gen_udp:send(Sock, SrcIp, SrcPort, Resp);
-        {error, Reason} ->
-            lager:debug("[dns_handler] resolver get error: ~p", [Reason])
-    end,
     {stop, normal, State}.
 
 %% @private
@@ -131,12 +121,12 @@ code_change(_OldVsn, State = #state{}, _Extra) ->
 %%% Internal functions
 %%%===================================================================
 
--spec resolver(Packet :: binary()) -> {ok, Resp :: binary()} | {error, Reason :: any()}.
+-spec resolver(Packet :: binary(), InbuiltResolver :: tuple()) -> {ok, Resp :: binary()} | {error, Reason :: any()}.
-resolver(Packet) when is_binary(Packet) ->
+resolver(Packet, InbuiltResolver) when is_binary(Packet) ->
-    resolver0(Packet, dns:decode_message(Packet)).
+    resolver0(Packet, dns:decode_message(Packet), InbuiltResolver).
-resolver0(Packet, QueryMsg = #dns_message{qc = 1, questions = [Question = #dns_query{name = QName, type = QType, class = QClass}|_]}) ->
+resolver0(Packet, QueryMsg = #dns_message{qc = 1, questions = [Question = #dns_query{name = QName, type = QType, class = QClass}|_]}, {M, F, A}) ->
     %% 查找是否是内置的域名
-    case search_inbuilt_domain(QName) of
+    case erlang:apply(M, F, A ++ [QName]) of
         {ok, Ip} ->
             Answer = #dns_rr {
                 name = QName,
@@ -157,6 +147,7 @@ resolver0(Packet, QueryMsg = #dns_message{qc = 1, questions = [Question = #dns_q
                 authority = [],
                 additional = []
             },
+            lager:debug("[dns_handler] inbuilt qnanme: ~p, ip: ~p", [QName, Ip]),
             {ok, dns:encode_message(RespMsg)};
         error ->
             case dns_cache:lookup(Question) of
@@ -184,7 +175,7 @@ resolver0(Packet, QueryMsg = #dns_message{qc = 1, questions = [Question = #dns_q
                     end
             end
     end;
-resolver0(_, Error) ->
+resolver0(_, Error, _InbuiltResolver) ->
     lager:warning("[dns_handler] decode dns query get error: ~p", [Error]),
     {error, Error}.
 
@@ -221,25 +212,16 @@ adjust_ttl(RR = #dns_rr{}, RemainingTTL) ->
 adjust_ttl(RR, _RemainingTTL) ->
     RR.
 
-search_inbuilt_domain(QName) when is_binary(QName) ->
-    Suffix = <<".iot.cn">>,
-    case dns_utils:ends_with(QName, Suffix) of
-        true ->
-            {ok, {192, 168, 1, 101}};
-        false ->
-            error
-    end.
-
 -spec build_ip_packet(SAddr :: inet:ip4_address(), DAddr :: inet:ip4_address(), SPort :: integer(), DPort :: integer(), Payload :: binary()) -> IpPacket :: binary().
-build_ip_packet(SAddr, DAddr, SPort, DPort, Payload) when is_integer(SPort), is_integer(DPort), is_binary(Payload) ->
+build_ip_packet(SAddr, DAddr, SPort, DPort, UdpPayload) when is_integer(SPort), is_integer(DPort), is_binary(UdpPayload) ->
-    ULen = 8 + byte_size(Payload),
+    ULen = 8 + byte_size(UdpPayload),
     RespUdpHeader = pkt:udp(#udp{
         sport = SPort,
         dport = DPort,
         ulen = ULen,
-        sum = dns_utils:udp_checksum(SAddr, DAddr, SPort, DPort, Payload)
+        sum = dns_utils:udp_checksum(SAddr, DAddr, SPort, DPort, UdpPayload)
     }),
-    IpPayload = <<RespUdpHeader/binary, Payload/binary>>,
+    IpPayload = <<RespUdpHeader/binary, UdpPayload/binary>>,
 
     IpPacket0 = #ipv4{
         len = 20 + ULen,
@@ -247,6 +229,7 @@ build_ip_packet(SAddr, DAddr, SPort, DPort, Payload) when is_integer(SPort), is_
         off = 0,
         mf = 0,
         sum = 0,
+        p = ?UDP_PROTOCOL,
         saddr = SAddr,
         daddr = DAddr,
         opt = <<>>

apps/dns_proxy/src/dns_proxy.erl

@@ -0,0 +1,19 @@
+%%%-------------------------------------------------------------------
+%%% @author anlicheng
+%%% @copyright (C) 2025, <COMPANY>
+%%% @doc
+%%%
+%%% @end
+%%% Created : 13. 12月 2025 15:20
+%%%-------------------------------------------------------------------
+-module(dns_proxy).
+-author("anlicheng").
+
+%% API
+-export([start_proxy/2]).
+
+start_proxy(Port, InbuiltResolver = {_M, _F, _A}) when is_integer(Port) ->
+    {ok, _} = dns_proxy_sup:start_resolver_pool(),
+    {ok, _} = dns_proxy_sup:start_handler_sup(),
+    {ok, _} = dns_proxy_sup:start_dns_server(Port, InbuiltResolver),
+    ok.

apps/dns_proxy/src/dns_proxy_sup.erl

@@ -8,8 +8,8 @@
 -behaviour(supervisor).
 
 -export([start_link/0]).
-
 -export([init/1]).
+-export([start_resolver_pool/0, start_handler_sup/0, start_dns_server/2]).
 
 -define(SERVER, ?MODULE).
 
@@ -27,12 +27,24 @@ start_link() ->
 %%                  modules => modules()}   % optional
 init([]) ->
     SupFlags = #{strategy => one_for_one, intensity => 1000, period => 3600},
+    {ok, {SupFlags, []}}.
 
+%% internal functions
+
+start_resolver_pool() ->
     {ok, PoolArgs} = application:get_env(dns_proxy, dns_resolver_pool),
-    ResolverPoolSpec = poolboy:child_spec(dns_resolver_pool, [{name, {local, dns_resolver_pool}}|PoolArgs], []),
+    PoolSpec = poolboy:child_spec(dns_resolver_pool, [{name, {local, dns_resolver_pool}}|PoolArgs], []),
+    case supervisor:start_child(?MODULE, PoolSpec) of
+        {ok, Pid} ->
+            {ok, Pid};
+        {error, {already_started, Pid}} ->
+            {ok, Pid};
+        StartError ->
+            StartError
+    end.
 
-    ChildSpecs = [
+start_handler_sup() ->
-        #{
+    Spec = #{
         id => dns_handler_sup,
         start => {dns_handler_sup, start_link, []},
         restart => permanent,
@@ -40,15 +52,29 @@ init([]) ->
         type => supervisor,
         modules => ['dns_handler_sup']
     },
-        #{
+    case supervisor:start_child(?MODULE, Spec) of
+        {ok, Pid} ->
+            {ok, Pid};
+        {error, {already_started, Pid}} ->
+            {ok, Pid};
+        StartError ->
+            StartError
+    end.
+
+start_dns_server(Port, InbuiltResolver) when is_integer(Port) ->
+    Spec = #{
         id => dns_server,
-            start => {dns_server, start_link, []},
+        start => {dns_server, start_link, [Port, InbuiltResolver]},
         restart => permanent,
         shutdown => 2000,
         type => worker,
         modules => ['dns_server']
-        }
+    },
-    ],
+    case supervisor:start_child(?MODULE, Spec) of
-    {ok, {SupFlags, [ResolverPoolSpec|ChildSpecs]}}.
+        {ok, Pid} ->
-
+            {ok, Pid};
-%% internal functions
+        {error, {already_started, Pid}} ->
+            {ok, Pid};
+        StartError ->
+            StartError
+    end.

apps/dns_proxy/src/dns_server.erl

@@ -1,27 +1,24 @@
 -module(dns_server).
--export([start_link/0, init/0]).
+-export([start_link/2, init/2]).
 
--define(LISTEN_PORT, 15353).
+start_link(Port, InbuiltResolver) when is_integer(Port) ->
+    {ok, spawn_link(?MODULE, init, [Port, InbuiltResolver])}.
 
-start_link() ->
+init(Port, InbuiltResolver) ->
-    {ok, spawn_link(?MODULE, init, [])}.
-
-init() ->
     dns_cache:init(),
-    %dns_zone_loader:load("priv/local.zone"),
+    {ok, Sock} = gen_udp:open(Port, [binary, {active, true}]),
-    {ok, Sock} = gen_udp:open(?LISTEN_PORT, [binary, {active, true}]),
+    io:format("DNS Forwarder started on UDP port ~p~n", [Port]),
-    io:format("DNS Forwarder started on UDP port ~p~n", [?LISTEN_PORT]),
+    loop(Sock, InbuiltResolver).
-    loop(Sock).
 
-loop(Sock) ->
+loop(Sock, InbuiltResolver) ->
     receive
         {udp, Sock, Ip, Port, Packet} ->
             lager:debug("[dns_server] ip: ~p, get a packet: ~p", [{Ip, Port}, Packet]),
             case dns_handler_sup:start_handler() of
                 {ok, HandlerPid} ->
-                    dns_handler:handle_ip_packet(HandlerPid, Sock, Ip, Port, Packet);
+                    dns_handler:handle_ip_packet(HandlerPid, Sock, Ip, Port, Packet, InbuiltResolver);
                 Error ->
                     lager:debug("[dns_server] start handler get error: ~p", [Error])
             end,
-            loop(Sock)
+            loop(Sock, InbuiltResolver)
     end.

apps/dns_proxy/src/dns_utils.erl

@@ -113,7 +113,8 @@ ip_checksum(#ipv4{hl = HL, tos = ToS, len = Len,
     end.
 
 test() ->
-    Bin = <<69,0,0,77,48,179,0,0,64,17,28,168,100,123,0,2,100,100,100,100,252,230,0,53,0,57,6,92,152,24,1,0,0,1,0,0,0,0,0,0,2,100,98,7,95,100,110,115,45,115,100,4,95,117,100,112,8,112,117,110,99,104,110,101,116,2,116,115,3,110,101,116,0,0,12,0,1>>,
+    %Bin = <<69,0,0,77,48,179,0,0,64,17,28,168,100,123,0,2,100,100,100,100,252,230,0,53,0,57,6,92,152,24,1,0,0,1,0,0,0,0,0,0,2,100,98,7,95,100,110,115,45,115,100,4,95,117,100,112,8,112,117,110,99,104,110,101,116,2,116,115,3,110,101,116,0,0,12,0,1>>,
+    Bin = <<69,0,0,93,0,0,0,0,64,6,77,86,100,100,100,100,100,123,0,2,0,53,196,102,0,73,39,7,215,192,129,128,0,1,0,1,0,0,0,0,2,108,98,7,95,100,110,115,45,115,100,4,95,117,100,112,8,112,117,110,99,104,110,101,116,2,116,115,3,110,101,116,0,0,12,0,1,192,12,0,12,0,1,0,0,1,44,0,4,192,168,1,101>>,
 
     {IPPacket = #ipv4{
         saddr = SAddr,
@@ -125,6 +126,6 @@ test() ->
 
     X = udp_checksum(SAddr, DAddr, SPort, DPort, UDPPayload),
 
-    lager:debug("ip_sum: ~p, y?: ~p, udp: ~p, checkSum: ~p, X is: ~p", [IpSum, ip_checksum(IPPacket), UDP, CheckSum, X]),
+    lager:debug("ip_sum: ~p, =: ~p, udp: ~p, checkSum: ~p, =: ~p", [IpSum, ip_checksum(IPPacket), UDP, CheckSum, X]),
 
     dns:decode_message(UDPPayload).

apps/dns_proxy/src/inbuilt_dns_resolver.erl

@@ -0,0 +1,24 @@
+%%%-------------------------------------------------------------------
+%%% @author anlicheng
+%%% @copyright (C) 2025, <COMPANY>
+%%% @doc
+%%%
+%%% @end
+%%% Created : 13. 12月 2025 15:44
+%%%-------------------------------------------------------------------
+-module(inbuilt_dns_resolver).
+-author("anlicheng").
+
+%% API
+-export([resolve/1]).
+
+-spec resolve(QName :: binary()) -> {ok, IpAddr :: inet:ip4_address()} | error.
+resolve(QName) when is_binary(QName) ->
+    Suffix = <<".punchnet.ts.net">>,
+    case dns_utils:ends_with(QName, Suffix) of
+        true ->
+            Ip4 = rand:uniform(254),
+            {ok, {192, 168, 1, Ip4}};
+        false ->
+            error
+    end.