简化dns的解析逻辑
This commit is contained in:
parent
5a9b680d2e
commit
6a044f155f
@ -9,18 +9,11 @@
|
||||
-module(dns_handler).
|
||||
-author("anlicheng").
|
||||
|
||||
-behaviour(gen_server).
|
||||
|
||||
-include_lib("dns_erlang/include/dns.hrl").
|
||||
-include_lib("pkt/include/pkt.hrl").
|
||||
-include("dns_proxy.hrl").
|
||||
|
||||
%% API
|
||||
-export([start_link/0]).
|
||||
|
||||
%% gen_server callbacks
|
||||
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
|
||||
-export([handle_ip_packet/5]).
|
||||
-export([handle/4]).
|
||||
|
||||
-define(SERVER, ?MODULE).
|
||||
-define(RESOLVER_POOL, dns_resolver_pool).
|
||||
@ -35,44 +28,7 @@
|
||||
%%% API
|
||||
%%%===================================================================
|
||||
|
||||
start_link() ->
|
||||
gen_server:start_link(?MODULE, [], []).
|
||||
|
||||
handle_ip_packet(Pid, Sock, SrcIp, SrcPort, Packet) when is_pid(Pid) ->
|
||||
gen_server:cast(Pid, {handle_ip_packet, Sock, SrcIp, SrcPort, Packet}).
|
||||
|
||||
%%%===================================================================
|
||||
%%% gen_server callbacks
|
||||
%%%===================================================================
|
||||
|
||||
%% @private
|
||||
%% @doc Initializes the server
|
||||
-spec(init(Args :: term()) ->
|
||||
{ok, State :: #state{}} | {ok, State :: #state{}, timeout() | hibernate} |
|
||||
{stop, Reason :: term()} | ignore).
|
||||
init([]) ->
|
||||
{ok, #state{}}.
|
||||
|
||||
%% @private
|
||||
%% @doc Handling call messages
|
||||
-spec(handle_call(Request :: term(), From :: {pid(), Tag :: term()},
|
||||
State :: #state{}) ->
|
||||
{reply, Reply :: term(), NewState :: #state{}} |
|
||||
{reply, Reply :: term(), NewState :: #state{}, timeout() | hibernate} |
|
||||
{noreply, NewState :: #state{}} |
|
||||
{noreply, NewState :: #state{}, timeout() | hibernate} |
|
||||
{stop, Reason :: term(), Reply :: term(), NewState :: #state{}} |
|
||||
{stop, Reason :: term(), NewState :: #state{}}).
|
||||
handle_call(_Request, _From, State = #state{}) ->
|
||||
{reply, ok, State}.
|
||||
|
||||
%% @private
|
||||
%% @doc Handling cast messages
|
||||
-spec(handle_cast(Request :: term(), 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(Sock, SrcIp, SrcPort, IpPacket) ->
|
||||
{#ipv4{saddr = ReqSAddr, daddr = ReqDAddr, p = Protocol}, ReqIpPayload} = pkt:ipv4(IpPacket),
|
||||
case Protocol =:= ?UDP_PROTOCOL of
|
||||
true ->
|
||||
@ -86,35 +42,7 @@ handle_cast({handle_ip_packet, Sock, SrcIp, SrcPort, IpPacket}, State) ->
|
||||
end;
|
||||
false ->
|
||||
logger:notice("[dns_handler] resolver invalid protocol: ~p", [Protocol])
|
||||
end,
|
||||
{stop, normal, State}.
|
||||
|
||||
%% @private
|
||||
%% @doc Handling all non call/cast messages
|
||||
-spec(handle_info(Info :: timeout() | term(), State :: #state{}) ->
|
||||
{noreply, NewState :: #state{}} |
|
||||
{noreply, NewState :: #state{}, timeout() | hibernate} |
|
||||
{stop, Reason :: term(), NewState :: #state{}}).
|
||||
handle_info(_Info, State) ->
|
||||
{noreply, State}.
|
||||
|
||||
%% @private
|
||||
%% @doc This function is called by a gen_server when it is about to
|
||||
%% terminate. It should be the opposite of Module:init/1 and do any
|
||||
%% necessary cleaning up. When it returns, the gen_server terminates
|
||||
%% with Reason. The return value is ignored.
|
||||
-spec(terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()),
|
||||
State :: #state{}) -> term()).
|
||||
terminate(_Reason, _State = #state{}) ->
|
||||
ok.
|
||||
|
||||
%% @private
|
||||
%% @doc Convert process state when code is changed
|
||||
-spec(code_change(OldVsn :: term() | {down, term()}, State :: #state{},
|
||||
Extra :: term()) ->
|
||||
{ok, NewState :: #state{}} | {error, Reason :: term()}).
|
||||
code_change(_OldVsn, State = #state{}, _Extra) ->
|
||||
{ok, State}.
|
||||
end.
|
||||
|
||||
%%%===================================================================
|
||||
%%% Internal functions
|
||||
@ -162,11 +90,8 @@ resolver0(Packet, QueryMsg = #dns_message{qc = 1, questions = [Question = #dns_q
|
||||
RespMsg = build_response(QueryMsg, Cache),
|
||||
{ok, dns:encode_message(RespMsg)};
|
||||
miss ->
|
||||
Ref = make_ref(),
|
||||
forward_to_upstream(Ref, Packet, QueryMsg),
|
||||
logger:debug("[dns_handler] cache is miss, forward_to_upstream"),
|
||||
receive
|
||||
{dns_resolver_reply, Ref, Resp} ->
|
||||
case forward_to_upstream(Packet, QueryMsg) of
|
||||
{ok, Resp} ->
|
||||
case dns:decode_message(Resp) of
|
||||
RespMsg = #dns_message{answers = Answers} ->
|
||||
logger:debug("[dns_handler] get a response answers: ~p", [Answers]),
|
||||
@ -175,10 +100,10 @@ resolver0(Packet, QueryMsg = #dns_message{qc = 1, questions = [Question = #dns_q
|
||||
Error ->
|
||||
logger:debug("[dns_handler] parse reply get error: ~p", [Error]),
|
||||
{ok, EmptyDnsResp}
|
||||
end
|
||||
after 5000 ->
|
||||
logger:debug("[dns_handler] forward_to_upstream timeout"),
|
||||
{ok, EmptyDnsResp}
|
||||
end;
|
||||
{error, Reason} ->
|
||||
logger:debug("[dns_handler] parse reply get error: ~p", [Reason]),
|
||||
{ok, EmptyDnsResp}
|
||||
end
|
||||
end
|
||||
end
|
||||
@ -187,11 +112,6 @@ resolver0(_, Error) ->
|
||||
logger:warning("[dns_handler] decode dns_query get error: ~p", [Error]),
|
||||
{error, Error}.
|
||||
|
||||
-spec forward_to_upstream(Ref :: reference(), Request :: binary(), QueryMsg :: #dns_message{}) -> no_return().
|
||||
forward_to_upstream(Ref, Request, QueryMsg) ->
|
||||
ReceiverPid = self(),
|
||||
poolboy:transaction(?RESOLVER_POOL, fun(Pid) -> dns_resolver:forward(Pid, ReceiverPid, Ref, Request, QueryMsg) end).
|
||||
|
||||
-spec build_response(QueryMsg :: #dns_message{}, Dns_cache :: #dns_cache{}) -> RespMsg :: #dns_message{}.
|
||||
build_response(QueryMsg, #dns_cache{expire_at = ExpireAt, answers = Answers, authority = Authority, additional = Additional, rc = RCode, flags = #{aa := AA}}) ->
|
||||
Now = os:system_time(second),
|
||||
@ -260,4 +180,24 @@ build_ip_packet(SAddr, DAddr, SPort, DPort, UdpPayload) when is_integer(SPort),
|
||||
IpCheckSum = dns_utils:ip_checksum(IpPacket0),
|
||||
IpHeader = pkt:ipv4(IpPacket0#ipv4{sum = IpCheckSum}),
|
||||
|
||||
<<IpHeader/binary, IpPayload/binary>>.
|
||||
<<IpHeader/binary, IpPayload/binary>>.
|
||||
|
||||
-spec forward_to_upstream(Request :: binary(), QueryMsg :: #dns_message{}) -> no_return().
|
||||
forward_to_upstream(Request, #dns_message{id = TxId, questions = [#dns_query{name = QName, type = QType, class = QClass}|_]}) ->
|
||||
{ok, {DnsIp, DnsPort}} = application:get_env(sdlan, public_dns_server),
|
||||
{ok, Socket} = gen_udp:open(0, [binary, {active, true}]),
|
||||
ok = gen_udp:send(Socket, DnsIp, DnsPort, Request),
|
||||
logger:debug("[dns_resolver] send to: ~p, packet: ~p", [{DnsIp, DnsPort}, Request]),
|
||||
receive
|
||||
{udp, Socket, DnsIp, DnsPort, Resp} ->
|
||||
try dns:decode_message(Resp) of
|
||||
#dns_message{id = TxId, questions = [#dns_query{name = QName, type = QType, class = QClass}|_]} ->
|
||||
{ok, Resp};
|
||||
_ ->
|
||||
{error, invalid_dns_response}
|
||||
catch error:Err ->
|
||||
{error, Err}
|
||||
end
|
||||
after 2000 ->
|
||||
{error, timeout}
|
||||
end.
|
||||
@ -14,11 +14,6 @@ loop(Sock) ->
|
||||
receive
|
||||
{udp, Sock, Ip, Port, Packet} ->
|
||||
logger: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);
|
||||
Error ->
|
||||
logger:debug("[dns_server] start handler get error: ~p", [Error])
|
||||
end,
|
||||
spawn(fun() -> dns_handler:handle(Sock, Ip, Port, Packet) end),
|
||||
loop(Sock)
|
||||
end.
|
||||
Loading…
x
Reference in New Issue
Block a user