add基础代码

apps/dns_proxy/src/dns_cache.erl

@@ -0,0 +1,17 @@
+-module(dns_cache).
+-export([init/0, lookup/1, insert/2]).
+
+-define(TABLE, dns_cache).
+
+init() ->
+    ets:new(?TABLE, [named_table, set, public, {read_concurrency, true}]).
+
+lookup(Key) ->
+    case ets:lookup(?TABLE, Key) of
+        [{_Key, Value}] -> {hit, Value};
+        [] -> miss
+    end.
+
+insert(Key, DNSMsg) ->
+    ets:insert(?TABLE, {Key, DNSMsg}),
+    ok.

apps/dns_proxy/src/dns_handler.erl

@@ -0,0 +1,48 @@
+%%%-------------------------------------------------------------------
+%%% @author anlicheng
+%%% @copyright (C) 2025, <COMPANY>
+%%% @doc
+%%%
+%%% @end
+%%% Created : 03. 12月 2025 17:27
+%%%-------------------------------------------------------------------
+-module(dns_handler).
+-author("anlicheng").
+
+-include_lib("dns_erlang/include/dns.hrl").
+-include_lib("dns_erlang/include/dns_records.hrl").
+-include_lib("dns_erlang/include/dns_terms.hrl").
+
+-export([handle_request/4]).
+
+handle_request(Sock, Ip, Port, Packet) ->
+    case dns:decode_message(Packet) of
+        {ok, Msg} ->
+            %Qname = (Msg#dns_message.questions)#dns_question.qname,
+            Qname = <<"www.baidu.com">>,
+            case dns_cache:lookup(Qname) of
+                {hit, R} ->
+                    Resp = build_response(Msg, R),
+                    gen_udp:send(Sock, Ip, Port, dns:encode_message(Resp));
+                miss ->
+                    forward_to_upstream(Sock, Ip, Port, Packet)
+            end;
+        _ ->
+            ok
+    end.
+
+forward_to_upstream(Sock, Ip, Port, Packet) ->
+    {SendSock, {UpIP, UpPort}} = dns_socket_pool:get_socket(),
+    ok = gen_udp:send(SendSock, UpIP, UpPort, Packet),
+
+    inet:setopts(SendSock, [{active, once}]),
+    receive
+        {udp, SendSock, _UIp, _UPort, Resp} ->
+            gen_udp:send(Sock, Ip, Port, Resp)
+    after 2000 ->
+        ok
+    end.
+
+build_response(Req, RR) ->
+    Msg = Req,
+    Msg#dns_message{answers=[RR], qr=true, aa=true}.

apps/dns_proxy/src/dns_handler_sup.erl

@@ -0,0 +1,71 @@
+%%%-------------------------------------------------------------------
+%%% @author anlicheng
+%%% @copyright (C) 2025, <COMPANY>
+%%% @doc
+%%%
+%%% @end
+%%% Created : 03. 12月 2025 17:29
+%%%-------------------------------------------------------------------
+-module(dns_handler_sup).
+-author("anlicheng").
+
+-behaviour(supervisor).
+
+%% API
+-export([start_link/0]).
+
+%% Supervisor callbacks
+-export([init/1]).
+-export([start_handler/4]).
+
+-define(SERVER, ?MODULE).
+
+%%%===================================================================
+%%% API functions
+%%%===================================================================
+
+%% @doc Starts the supervisor
+-spec(start_link() -> {ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
+start_link() ->
+    supervisor:start_link({local, ?SERVER}, ?MODULE, []).
+
+%%%===================================================================
+%%% Supervisor callbacks
+%%%===================================================================
+
+%% @private
+%% @doc Whenever a supervisor is started using supervisor:start_link/[2,3],
+%% this function is called by the new process to find out about
+%% restart strategy, maximum restart frequency and child
+%% specifications.
+-spec(init(Args :: term()) ->
+    {ok, {SupFlags :: {RestartStrategy :: supervisor:strategy(),
+        MaxR :: non_neg_integer(), MaxT :: non_neg_integer()},
+        [ChildSpec :: supervisor:child_spec()]}}
+    | ignore | {error, Reason :: term()}).
+init([]) ->
+    SupFlags = #{strategy => simple_one_for_one, intensity => 0, period => 1},
+    Spec = #{
+        id => dns_handler,
+        start => {'dns_handler', dns_handler, []},
+        restart => temporary,
+        shutdown => 2000,
+        type => worker,
+        modules => ['dns_handler']
+    },
+
+    {ok, {SupFlags, [Spec]}}.
+
+%%%===================================================================
+%%% Internal functions
+%%%===================================================================
+
+start_handler(Sock, Ip, Port, Packet) ->
+    case supervisor:start_child(?MODULE, [Sock, Ip, Port, Packet]) of
+        {ok, Pid} ->
+            {ok, Pid};
+        {error, {already_started, Pid}} ->
+            {ok, Pid};
+        StartError ->
+            StartError
+    end.

apps/dns_proxy/src/dns_proxy.app.src

@@ -4,7 +4,11 @@
   {registered, []},
   {mod, {dns_proxy_app, []}},
   {applications,
-   [kernel,
+   [
+    sync,
+    lager,
+    dns_erlang,
+    kernel,
     stdlib
    ]},
   {env,[]},

apps/dns_proxy/src/dns_proxy_sup.erl

@@ -26,10 +26,17 @@ start_link() ->
 %%                  type => worker(),       % optional
 %%                  modules => modules()}   % optional
 init([]) ->
-    SupFlags = #{strategy => one_for_all,
-                 intensity => 0,
-                 period => 1},
-    ChildSpecs = [],
+    SupFlags = #{strategy => one_for_one, intensity => 1000, period => 3600},
+    ChildSpecs = [
+        #{
+            id => dns_handler_sup,
+            start => {dns_handler_sup, start_link, []},
+            restart => permanent,
+            shutdown => 2000,
+            type => supervisor,
+            modules => ['dns_handler_sup']
+        }
+    ],
     {ok, {SupFlags, ChildSpecs}}.
 
 %% internal functions

apps/dns_proxy/src/dns_server.erl

@@ -0,0 +1,30 @@
+-module(dns_server).
+-export([start/0, stop/0]).
+
+-define(LISTEN_PORT, 53).
+
+start() ->
+    dns_cache:init(),
+    dns_zone_loader:load("priv/local.zone"),
+
+    %% 配置上游 DNS
+    Upstreams = [
+        {{8,8,8,8}, 53},
+        {{1,1,1,1}, 53}
+    ],
+    dns_socket_pool:start_link(Upstreams),
+
+    {ok, Sock} = gen_udp:open(?LISTEN_PORT, [binary, {active, true}]),
+    io:format("DNS Forwarder started on UDP port ~p~n", [?LISTEN_PORT]),
+    loop(Sock).
+
+stop() ->
+    gen_udp:close(?LISTEN_PORT),
+    ok.
+
+loop(Sock) ->
+    receive
+        {udp, Sock, Ip, Port, Packet} ->
+            dns_handler_sup:start_handler(Sock, Ip, Port, Packet),
+            loop(Sock)
+    end.

apps/dns_proxy/src/dns_socket_pool.erl

@@ -0,0 +1,26 @@
+-module(dns_socket_pool).
+-behaviour(gen_server).
+
+-export([start_link/1, get_socket/0]).
+-export([init/1, handle_call/3]).
+
+-record(state, {sockets=[]}).
+
+start_link(Ups) ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, Ups, []).
+
+get_socket() ->
+    gen_server:call(?MODULE, get).
+
+init(Upstreams) ->
+    %% 为多个上游 DNS 建 socket
+    Sockets = lists:map(fun({IP, Port}) ->
+        {ok, Sock} = gen_udp:open(0, [binary, {active, false}]),
+        {Sock, {IP, Port}}
+                        end, Upstreams),
+    {ok, #state{sockets=Sockets}}.
+
+handle_call(get, _From, State=#state{sockets=Socks}) ->
+    %% 简单 round-robin
+    [H|T] = Socks,
+    {reply, H, State#state{sockets=T ++ [H]}}.

apps/dns_proxy/src/dns_zone_loader.erl

@@ -0,0 +1,13 @@
+-module(dns_zone_loader).
+-export([load/1]).
+
+-include_lib("dns_erlang/include/dns.hrl").
+
+load(Path) ->
+    {ok, Bin} = file:read_file(Path),
+    {ok, Records} = dns_zone:decode(Bin), % dns_erlang 提供
+    lists:foreach(fun(R) ->
+        Name = R#dns_rr.name,
+        dns_cache:insert(Name, R)
+                  end, Records),
+    ok.

config/sys.config

@@ -1,3 +1,46 @@
 [
-  {dns_proxy, []}
+  {dns_proxy, [
+
+    %% 公共的dns域名解析服务
+    {public_dns_servers, [
+      {{8,8,8,8}, 53},
+      {{1,1,1,1}, 53}
+    ]}
+
+  ]},
+
+  %% 系统日志配置，系统日志为lager, 支持日志按日期自动分割
+  {lager, [
+    {colored, true},
+    %% Whether to write a crash log, and where. Undefined means no crash logger.
+    {crash_log, "trade_hub.crash.log"},
+    %% Maximum size in bytes of events in the crash log - defaults to 65536
+    {crash_log_msg_size, 65536},
+    %% Maximum size of the crash log in bytes, before its rotated, set
+    %% to 0 to disable rotation - default is 0
+    {crash_log_size, 10485760},
+    %% What time to rotate the crash log - default is no time
+    %% rotation. See the README for a description of this format.
+    {crash_log_date, "$D0"},
+    %% Number of rotated crash logs to keep, 0 means keep only the
+    %% current one - default is 0
+    {crash_log_count, 5},
+    %% Whether to redirect error_logger messages into lager - defaults to true
+    {error_logger_redirect, true},
+
+    %% How big the gen_event mailbox can get before it is switched into sync mode
+    {async_threshold, 20},
+    %% Switch back to async mode, when gen_event mailbox size decrease from `async_threshold'
+    %% to async_threshold - async_threshold_window
+    {async_threshold_window, 5},
+
+    {handlers, [
+      %% debug | info | warning | error, 日志级别
+      {lager_console_backend, debug},
+      {lager_file_backend, [{file, "debug.log"}, {level, debug}, {size, 314572800}]},
+      {lager_file_backend, [{file, "notice.log"}, {level, notice}, {size, 314572800}]},
+      {lager_file_backend, [{file, "error.log"}, {level, error}, {size, 314572800}]},
+      {lager_file_backend, [{file, "info.log"}, {level, info}, {size, 314572800}]}
+    ]}
+  ]}
 ].

rebar.config

@@ -1,5 +1,10 @@
 {erl_opts, [debug_info]}.
-{deps, []}.
+{deps, [
+    {dns_erlang, ".*", {git, "https://github.com/dnsimple/dns_erlang.git", {tag, "v4.4.0"}}},
+    {sync, ".*", {git, "https://github.com/rustyio/sync.git", {branch, "master"}}},
+    {parse_trans, ".*", {git, "https://github.com/uwiger/parse_trans", {tag, "3.0.0"}}},
+    {lager, ".*", {git,"https://github.com/erlang-lager/lager.git", {tag, "3.9.2"}}}
+]}.
 
 {relx, [{release, {dns_proxy, "0.1.0"},
          [dns_proxy,
@@ -30,3 +35,6 @@
                       %% {mode, minimal}
                      ]
             }]}]}.
+
+{erl_opts, [{parse_transform,lager_transform}]}.
+{rebar_packages_cdn, "https://hexpm.upyun.com"}.