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authorRaimo Niskanen <[email protected]>2011-04-15 17:57:40 +0200
committerRaimo Niskanen <[email protected]>2011-04-21 08:54:13 +0200
commit096eccb19e4d8b3799cbcf1b881a6023401c3ff4 (patch)
treeeea80f43e7870d33eb982dfe7e757b5ffeba92a9
parent33ed693175e5da97f37e4a3a0eb08a60f22e2b6c (diff)
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Add DNS proxy and first test case for late answer
-rw-r--r--lib/kernel/test/inet_res_SUITE.erl127
1 files changed, 115 insertions, 12 deletions
diff --git a/lib/kernel/test/inet_res_SUITE.erl b/lib/kernel/test/inet_res_SUITE.erl
index 5fc8df475d..6064a9b2d9 100644
--- a/lib/kernel/test/inet_res_SUITE.erl
+++ b/lib/kernel/test/inet_res_SUITE.erl
@@ -27,7 +27,8 @@
-export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1,
init_per_group/2,end_per_group/2,
init_per_testcase/2, end_per_testcase/2]).
--export([basic/1, resolve/1, edns0/1, txt_record/1, files_monitor/1]).
+-export([basic/1, resolve/1, edns0/1, txt_record/1, files_monitor/1,
+ last_ms_answer/1]).
-export([
gethostbyaddr/0, gethostbyaddr/1,
gethostbyaddr_v6/0, gethostbyaddr_v6/1,
@@ -45,6 +46,7 @@ suite() -> [{ct_hooks,[ts_install_cth]}].
all() ->
[basic, resolve, edns0, txt_record, files_monitor,
+ last_ms_answer,
gethostbyaddr, gethostbyaddr_v6, gethostbyname,
gethostbyname_v6, getaddr, getaddr_v6, ipv4_to_ipv6,
host_and_addr].
@@ -64,16 +66,15 @@ init_per_group(_GroupName, Config) ->
end_per_group(_GroupName, Config) ->
Config.
-zone_dir(basic) ->
- otptest;
-zone_dir(resolve) ->
- otptest;
-zone_dir(edns0) ->
- otptest;
-zone_dir(files_monitor) ->
- otptest;
-zone_dir(_) ->
- undefined.
+zone_dir(TC) ->
+ case TC of
+ basic -> otptest;
+ resolve -> otptest;
+ edns0 -> otptest;
+ files_monitor -> otptest;
+ last_ms_answer -> otptest;
+ _ -> undefined
+ end.
init_per_testcase(Func, Config) ->
PrivDir = ?config(priv_dir, Config),
@@ -184,6 +185,88 @@ ns_printlog(Fname) ->
ok
end.
+%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Behaviour modifying nameserver proxy
+
+proxy_start(TC, {NS,P}) ->
+ Tag = make_ref(),
+ Parent = self(),
+ Pid =
+ spawn_link(
+ fun () ->
+ try proxy_start(TC, NS, P, Parent, Tag)
+ catch C:X ->
+ io:format(
+ "~w: ~w:~p ~p~n",
+ [self(),C,X,erlang:get_stacktrace()])
+ end
+ end),
+ receive {started,Tag,Port} ->
+ ProxyNS = {{127,0,0,1},Port},
+ {proxy,Pid,Tag,ProxyNS}
+ end.
+
+proxy_start(TC, NS, P, Parent, Tag) ->
+ {ok,Outbound} = gen_udp:open(0, [binary]),
+ ok = gen_udp:connect(Outbound, NS, P),
+ {ok,Inbound} = gen_udp:open(0, [binary]),
+ {ok,Port} = inet:port(Inbound),
+ Parent ! {started,Tag,Port},
+ proxy(TC, Outbound, NS, P, Inbound).
+
+
+%% To provoke the last_ms_answer bug (OTP-9221) the proxy
+%% * Relays the query to the right nameserver
+%% * Intercepts the reply but holds it until the timer that
+%% was started when receiving the query fires.
+%% * Repeats the reply with incorrect query ID a number of
+%% times with a short interval.
+%% * Sends the correct reply, to give a correct test result
+%% after bug correction.
+%%
+%% The repetition of an incorrect answer with tight interval will keep
+%% inet_res in an inner loop in the code that decrements the remaining
+%% time until it hits 0 which triggers a crash, if the outer timeout
+%% parameter to inet_res:resolve is so short that it runs out during
+%% these repetitions.
+proxy(last_ms_answer, Outbound, NS, P, Inbound) ->
+ receive
+ {udp,Inbound,SrcIP,SrcPort,Data} ->
+ Time =
+ inet_db:res_option(timeout) div inet_db:res_option(retry),
+ Tag = erlang:make_ref(),
+ erlang:send_after(Time - 10, self(), {time,Tag}),
+ ok = gen_udp:send(Outbound, NS, P, Data),
+ receive
+ {udp,Outbound,NS,P,Reply} ->
+ {ok,Msg} = inet_dns:decode(Reply),
+ Hdr = inet_dns:msg(Msg, header),
+ Id = inet_dns:header(Hdr, id),
+ BadHdr =
+ inet_dns:make_header(Hdr, id, (Id+1) band 16#ffff),
+ BadMsg = inet_dns:make_msg(Msg, header, BadHdr),
+ BadReply = inet_dns:encode(BadMsg),
+ receive
+ {time,Tag} ->
+ proxy__last_ms_answer(
+ Inbound, SrcIP, SrcPort, BadReply, Reply, 30)
+ end
+ end
+ end.
+
+proxy__last_ms_answer(Socket, IP, Port, _, Reply, 0) ->
+ ok = gen_udp:send(Socket, IP, Port, Reply);
+proxy__last_ms_answer(Socket, IP, Port, BadReply, Reply, N) ->
+ ok = gen_udp:send(Socket, IP, Port, BadReply),
+ receive after 1 -> ok end,
+ proxy__last_ms_answer(Socket, IP, Port, BadReply, Reply, N-1).
+
+proxy_wait({proxy,Pid,_,_}) ->
+ Mref = erlang:monitor(process, Pid),
+ receive {'DOWN',Mref,_,_,_} -> ok end.
+
+proxy_ns({proxy,_,_,ProxyNS}) -> ProxyNS.
+
%%
%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -204,7 +287,7 @@ basic(Config) when is_list(Config) ->
{ok,Msg1} = inet_dns:decode(Bin1),
%%
%% resolve
- {ok,Msg2} = inet_res:resolve(Name, in, a, [{nameservers,[NS]}]),
+ {ok,Msg2} = inet_res:resolve(Name, in, a, [{nameservers,[NS]},verbose]),
io:format("~p~n", [Msg2]),
[RR2] = inet_dns:msg(Msg2, anlist),
IP = inet_dns:rr(RR2, data),
@@ -474,6 +557,26 @@ do_files_monitor(Config) ->
ok.
%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+last_ms_answer(doc) ->
+ ["Answer just when timeout is triggered (OTP-9221)"];
+last_ms_answer(Config) when is_list(Config) ->
+ NS = ns(Config),
+ Name = "ns.otptest",
+ %%IP = {127,0,0,254},
+ Time = inet_db:res_option(timeout) div inet_db:res_option(retry),
+ PSpec = proxy_start(last_ms_answer, NS),
+ ProxyNS = proxy_ns(PSpec),
+ %%
+ %% resolve; whith short timeout to trigger Timeout =:= 0 in inet_res
+ {error,timeout} =
+ inet_res:resolve(
+ Name, in, a, [{nameservers,[ProxyNS]},verbose], Time + 10),
+ %%
+ proxy_wait(PSpec),
+ ok.
+
+%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Compatibility tests. Call the inet_SUITE tests, but with
%% lookup = [file,dns] instead of [native]