简化dns的查询逻辑
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@ -73,64 +73,13 @@ handle_call(_Request, _From, State = #state{}) ->
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{noreply, NewState :: #state{}, timeout() | hibernate} |
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{stop, Reason :: term(), NewState :: #state{}}).
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handle_cast(handle, State = #state{socket = Sock, src_ip = SrcIp, src_port = SrcPort, packet = Packet}) ->
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case dns:decode_message(Packet) of
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QueryMsg = #dns_message{qc = 1, questions = [Question = #dns_query{name = QName, type = QType, class = QClass}|_]} ->
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%% 查找是否是内置的域名
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case search_inbuilt_domain(QName) of
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{ok, Ip} ->
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Answer = #dns_rr {
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name = QName,
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type = QType,
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class = QClass,
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ttl = 300,
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data = #dns_rrdata_a {
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ip = Ip
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}
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},
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RespMsg = QueryMsg#dns_message{
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qr = true,
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ra = true,
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anc = 1,
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auc = 0,
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adc = 0,
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answers = [Answer],
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authority = [],
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additional = []
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},
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gen_udp:send(Sock, SrcIp, SrcPort, dns:encode_message(RespMsg)),
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{stop, normal, State};
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error ->
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case dns_cache:lookup(Question) of
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{hit, Cache} ->
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lager:debug("[dns_handler] question: ~p, hit cache answers: ~p", [Question, Cache#dns_cache.answers]),
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RespMsg = build_response(QueryMsg, Cache),
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gen_udp:send(Sock, SrcIp, SrcPort, dns:encode_message(RespMsg)),
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{stop, normal, State};
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miss ->
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lager:debug("[dns_handler] cache is miss"),
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Ref = make_ref(),
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forward_to_upstream(Ref, Packet, QueryMsg),
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receive
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{dns_resolver_reply, Ref, Resp} ->
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case dns:decode_message(Resp) of
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RespMsg = #dns_message{answers = Answers} ->
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lager:debug("[dns_handler] get a response answers: ~p", [Answers]),
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dns_cache:insert(Question, RespMsg),
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case resolver(Packet) of
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{ok, Resp} ->
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gen_udp:send(Sock, SrcIp, SrcPort, Resp);
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Other ->
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lager:debug("[dns_handler] parse reply get error: ~p", [Other])
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{error, Reason} ->
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lager:debug("[dns_handler] resolver get error: ~p", [Reason])
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end,
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{stop, normal, State}
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after 5000 ->
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{stop, normal, State}
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end
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end
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end;
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Other ->
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lager:warning("[dns_handler] decode dns query get error: ~p", [Other]),
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{stop, normal, State}
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end.
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{stop, normal, State}.
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%% @private
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%% @doc Handling all non call/cast messages
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@ -163,6 +112,63 @@ code_change(_OldVsn, State = #state{}, _Extra) ->
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%%% Internal functions
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%%%===================================================================
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-spec resolver(Packet :: binary()) -> {ok, Resp :: binary()} | {error, Reason :: any()}.
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resolver(Packet) when is_binary(Packet) ->
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resolver0(Packet, dns:decode_message(Packet)).
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resolver0(Packet, QueryMsg = #dns_message{qc = 1, questions = [Question = #dns_query{name = QName, type = QType, class = QClass}|_]}) ->
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%% 查找是否是内置的域名
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case search_inbuilt_domain(QName) of
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{ok, Ip} ->
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Answer = #dns_rr {
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name = QName,
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type = QType,
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class = QClass,
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ttl = 300,
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data = #dns_rrdata_a {
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ip = Ip
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}
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},
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RespMsg = QueryMsg#dns_message{
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qr = true,
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ra = true,
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anc = 1,
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auc = 0,
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adc = 0,
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answers = [Answer],
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authority = [],
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additional = []
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},
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{ok, dns:encode_message(RespMsg)};
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error ->
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case dns_cache:lookup(Question) of
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{hit, Cache} ->
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lager:debug("[dns_handler] question: ~p, hit cache answers: ~p", [Question, Cache#dns_cache.answers]),
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RespMsg = build_response(QueryMsg, Cache),
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{ok, dns:encode_message(RespMsg)};
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miss ->
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lager:debug("[dns_handler] cache is miss"),
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Ref = make_ref(),
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forward_to_upstream(Ref, Packet, QueryMsg),
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receive
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{dns_resolver_reply, Ref, Resp} ->
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case dns:decode_message(Resp) of
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RespMsg = #dns_message{answers = Answers} ->
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lager:debug("[dns_handler] get a response answers: ~p", [Answers]),
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dns_cache:insert(Question, RespMsg),
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{ok, Resp};
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Error ->
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lager:debug("[dns_handler] parse reply get error: ~p", [Error]),
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Error
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end
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after 5000 ->
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{error, timeout}
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end
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end
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end;
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resolver0(_, Error) ->
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lager:warning("[dns_handler] decode dns query get error: ~p", [Error]),
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Error.
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-spec forward_to_upstream(Ref :: reference(), Request :: binary(), QueryMsg :: #dns_message{}) -> no_return().
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forward_to_upstream(Ref, Request, QueryMsg) ->
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ReceiverPid = self(),
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@ -8,6 +8,7 @@
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sync,
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lager,
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dns_erlang,
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pkt,
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poolboy,
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kernel,
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stdlib
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@ -2,6 +2,7 @@
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{deps, [
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{dns_erlang, ".*", {git, "https://github.com/dnsimple/dns_erlang.git", {tag, "v4.4.0"}}},
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{poolboy, ".*", {git, "https://github.com/devinus/poolboy.git", {tag, "1.5.1"}}},
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{pkt, ".*", {git, "https://github.com/msantos/pkt.git", {tag, "0.6.0"}}},
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{sync, ".*", {git, "https://github.com/rustyio/sync.git", {branch, "master"}}},
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{parse_trans, ".*", {git, "https://github.com/uwiger/parse_trans", {tag, "3.0.0"}}},
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{lager, ".*", {git,"https://github.com/erlang-lager/lager.git", {tag, "3.9.2"}}}
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