%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2008-2018. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
-module(ssl_payload_SUITE).
%% Note: This directive should only be used in test suites.
-compile(export_all).
-include_lib("common_test/include/ct.hrl").
-define(TIMEOUT, 600000).
%%--------------------------------------------------------------------
%% Common Test interface functions -----------------------------------
%%--------------------------------------------------------------------
all() ->
[
{group, 'tlsv1.2'},
{group, 'tlsv1.1'},
{group, 'tlsv1'},
{group, 'sslv3'}
].
groups() ->
[
{'tlsv1.2', [], payload_tests()},
{'tlsv1.1', [], payload_tests()},
{'tlsv1', [], payload_tests()},
{'sslv3', [], payload_tests()}
].
payload_tests() ->
[server_echos_passive_small,
server_echos_active_once_small,
server_echos_active_small,
client_echos_passive_small,
client_echos_active_once_small,
client_echos_active_small,
server_echos_passive_big,
server_echos_active_once_big,
server_echos_active_big,
client_echos_passive_big,
client_echos_active_once_big,
client_echos_active_big,
server_echos_passive_huge,
server_echos_active_once_huge,
server_echos_active_huge,
client_echos_passive_huge,
client_echos_active_once_huge,
client_echos_active_huge].
init_per_suite(Config) ->
catch crypto:stop(),
try crypto:start() of
ok ->
ssl_test_lib:clean_start(),
{ok, _} =
make_certs:all(
proplists:get_value(data_dir, Config),
proplists:get_value(priv_dir, Config)),
ssl_test_lib:cert_options(Config)
catch _:_ ->
{skip, "Crypto did not start"}
end.
end_per_suite(_Config) ->
ssl:stop(),
application:stop(crypto).
init_per_group(GroupName, Config) ->
case ssl_test_lib:is_tls_version(GroupName) of
true ->
case ssl_test_lib:sufficient_crypto_support(GroupName) of
true ->
ssl_test_lib:init_tls_version(GroupName, Config);
false ->
{skip, "Missing crypto support"}
end;
_ ->
ssl:start(),
Config
end.
end_per_group(GroupName, Config) ->
case ssl_test_lib:is_tls_version(GroupName) of
true ->
ssl_test_lib:clean_tls_version(Config);
false ->
Config
end.
init_per_testcase(TestCase, Config)
when TestCase == server_echos_passive_huge;
TestCase == server_echos_active_once_huge;
TestCase == server_echos_active_huge;
TestCase == client_echos_passive_huge;
TestCase == client_echos_active_once_huge;
TestCase == client_echos_active_huge ->
case erlang:system_info(system_architecture) of
"sparc-sun-solaris2.10" ->
{skip,"Will take to long time on an old Sparc"};
_ ->
ct:timetrap({seconds, 90}),
Config
end;
init_per_testcase(TestCase, Config)
when TestCase == server_echos_passive_big;
TestCase == server_echos_active_once_big;
TestCase == server_echos_active_big;
TestCase == client_echos_passive_big;
TestCase == client_echos_active_once_big;
TestCase == client_echos_active_big ->
ct:timetrap({seconds, 60}),
Config;
init_per_testcase(_TestCase, Config) ->
ct:timetrap({seconds, 15}),
Config.
end_per_testcase(_TestCase, Config) ->
Config.
%%--------------------------------------------------------------------
%% Test Cases --------------------------------------------------------
%%--------------------------------------------------------------------
server_echos_passive_small() ->
[{doc, "Client sends 1000 bytes in passive mode to server, that receives them, "
"sends them back, and closes."}].
server_echos_passive_small(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 100),
server_echos_passive(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
server_echos_active_once_small() ->
[{doc, "Client sends 1000 bytes in active once mode to server, that receives "
" them, sends them back, and closes."}].
server_echos_active_once_small(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 100),
server_echos_active_once(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
server_echos_active_small() ->
[{doc, "Client sends 1000 bytes in active mode to server, that receives them, "
"sends them back, and closes."}].
server_echos_active_small(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 100),
server_echos_active(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
client_echos_passive_small() ->
[{doc, "Server sends 1000 bytes in passive mode to client, that receives them, "
"sends them back, and closes."}].
client_echos_passive_small(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 100),
client_echos_passive(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
client_echos_active_once_small() ->
["Server sends 1000 bytes in active once mode to client, that receives "
"them, sends them back, and closes."].
client_echos_active_once_small(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 100),
client_echos_active_once(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
client_echos_active_small() ->
[{doc, "Server sends 1000 bytes in active mode to client, that receives them, "
"sends them back, and closes."}].
client_echos_active_small(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 100),
client_echos_active(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
server_echos_passive_big() ->
[{doc, "Client sends 50000 bytes to server in passive mode, that receives them, "
"sends them back, and closes."}].
server_echos_passive_big(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 5000),
server_echos_passive(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
server_echos_active_once_big() ->
[{doc,"Client sends 50000 bytes to server in active once mode, that receives "
"them, sends them back, and closes."}].
server_echos_active_once_big(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 5000),
server_echos_active_once(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
server_echos_active_big() ->
[{doc, "Client sends 50000 bytes to server in active once mode, that receives "
" them, sends them back, and closes."}].
server_echos_active_big(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 5000),
server_echos_active(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
client_echos_passive_big() ->
[{doc, "Server sends 50000 bytes to client in passive mode, that receives them, "
"sends them back, and closes."}].
client_echos_passive_big(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 5000),
client_echos_passive(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
client_echos_active_once_big() ->
[{doc, "Server sends 50000 bytes to client in active once mode, that receives"
" them, sends them back, and closes."}].
client_echos_active_once_big(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 5000),
client_echos_active_once(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
client_echos_active_big() ->
[{doc, "Server sends 50000 bytes to client in active mode, that receives them, "
"sends them back, and closes."}].
client_echos_active_big(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 5000),
client_echos_active(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
server_echos_passive_huge() ->
[{doc, "Client sends 500000 bytes to server in passive mode, that receives "
" them, sends them back, and closes."}].
server_echos_passive_huge(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 50000),
server_echos_passive(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
server_echos_active_once_huge() ->
[{doc, "Client sends 500000 bytes to server in active once mode, that receives "
"them, sends them back, and closes."}].
server_echos_active_once_huge(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 50000),
server_echos_active_once(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
server_echos_active_huge() ->
[{doc, "Client sends 500000 bytes to server in active mode, that receives them, "
"sends them back, and closes."}].
server_echos_active_huge(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 50000),
server_echos_active(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
client_echos_passive_huge() ->
[{doc, "Server sends 500000 bytes to client in passive mode, that receives "
"them, sends them back, and closes."}].
client_echos_passive_huge(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 50000),
client_echos_passive(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
client_echos_active_once_huge() ->
[{doc, "Server sends 500000 bytes to client in active once mode, that receives "
"them, sends them back, and closes."}].
client_echos_active_once_huge(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 50000),
client_echos_active_once(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
client_echos_active_huge() ->
[{doc, "Server sends 500000 bytes to client in active mode, that receives them, "
"sends them back, and closes."}].
client_echos_active_huge(Config) when is_list(Config) ->
ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
ServerOpts = ssl_test_lib:ssl_options(server_opts, Config),
{ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
%%
Data = binary:copy(<<"1234567890">>, 50000),
client_echos_active(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname).
%%--------------------------------------------------------------------
%% Internal functions ------------------------------------------------
%%--------------------------------------------------------------------
server_echos_passive(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname) ->
Length = byte_size(Data),
Server =
ssl_test_lib:start_server(
[{node, ServerNode}, {port, 0},
{from, self()},
{mfa, {?MODULE, echoer, [Length]}},
{options, [{active, false}, {mode, binary} | ServerOpts]}]),
Port = ssl_test_lib:inet_port(Server),
Client =
ssl_test_lib:start_client(
[{node, ClientNode}, {port, Port},
{host, Hostname},
{from, self()},
{mfa, {?MODULE, sender, [Data]}},
{options, [{active, false}, {mode, binary} | ClientOpts]}]),
%%
ssl_test_lib:check_result(Server, ok, Client, ok),
%%
ssl_test_lib:close(Server),
ssl_test_lib:close(Client).
server_echos_active_once(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname) ->
Length = byte_size(Data),
Server =
ssl_test_lib:start_server(
[{node, ServerNode}, {port, 0},
{from, self()},
{mfa, {?MODULE, echoer_active_once, [Length]}},
{options, [{active, once}, {mode, binary} | ServerOpts]}]),
Port = ssl_test_lib:inet_port(Server),
Client =
ssl_test_lib:start_client(
[{node, ClientNode}, {port, Port},
{host, Hostname},
{from, self()},
{mfa, {?MODULE, sender_active_once, [Data]}},
{options, [{active, once}, {mode, binary} | ClientOpts]}]),
%%
ssl_test_lib:check_result(Server, ok, Client, ok),
%%
ssl_test_lib:close(Server),
ssl_test_lib:close(Client).
server_echos_active(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname) ->
Length = byte_size(Data),
Server =
ssl_test_lib:start_server(
[{node, ServerNode}, {port, 0},
{from, self()},
{mfa, {?MODULE, echoer_active, [Length]}},
{options, [{active, true}, {mode, binary} | ServerOpts]}]),
Port = ssl_test_lib:inet_port(Server),
Client =
ssl_test_lib:start_client(
[{node, ClientNode}, {port, Port},
{host, Hostname},
{from, self()},
{mfa, {?MODULE, sender_active, [Data]}},
{options, [{active, true}, {mode, binary} | ClientOpts]}]),
%%
ssl_test_lib:check_result(Server, ok, Client, ok),
%%
ssl_test_lib:close(Server),
ssl_test_lib:close(Client).
client_echos_passive(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname) ->
Length = byte_size(Data),
Server =
ssl_test_lib:start_server(
[{node, ServerNode}, {port, 0},
{from, self()},
{mfa, {?MODULE, sender, [Data]}},
{options, [{active, false}, {mode, binary} | ServerOpts]}]),
Port = ssl_test_lib:inet_port(Server),
Client =
ssl_test_lib:start_client(
[{node, ClientNode}, {port, Port},
{host, Hostname},
{from, self()},
{mfa, {?MODULE, echoer, [Length]}},
{options, [{active, false}, {mode, binary} | ClientOpts]}]),
%%
ssl_test_lib:check_result(Server, ok, Client, ok),
%%
ssl_test_lib:close(Server),
ssl_test_lib:close(Client).
client_echos_active_once(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname) ->
Length = byte_size(Data),
Server =
ssl_test_lib:start_server(
[{node, ServerNode}, {port, 0},
{from, self()},
{mfa, {?MODULE, sender_active_once, [Data]}},
{options, [{active, once}, {mode, binary} | ServerOpts]}]),
Port = ssl_test_lib:inet_port(Server),
Client =
ssl_test_lib:start_client(
[{node, ClientNode}, {port, Port},
{host, Hostname},
{from, self()},
{mfa, {?MODULE, echoer_active_once, [Length]}},
{options,[{active, once}, {mode, binary} | ClientOpts]}]),
%%
ssl_test_lib:check_result(Server, ok, Client, ok),
%%
ssl_test_lib:close(Server),
ssl_test_lib:close(Client).
client_echos_active(
Data, ClientOpts, ServerOpts, ClientNode, ServerNode, Hostname) ->
Length = byte_size(Data),
Server =
ssl_test_lib:start_server(
[{node, ServerNode}, {port, 0},
{from, self()},
{mfa, {?MODULE, sender_active, [Data]}},
{options, [{active, true}, {mode, binary} | ServerOpts]}]),
Port = ssl_test_lib:inet_port(Server),
Client =
ssl_test_lib:start_client(
[{node, ClientNode}, {port, Port},
{host, Hostname},
{from, self()},
{mfa, {?MODULE, echoer_active, [Length]}},
{options, [{active, true}, {mode, binary} | ClientOpts]}]),
%
ssl_test_lib:check_result(Server, ok, Client, ok),
%%
ssl_test_lib:close(Server),
ssl_test_lib:close(Client).
send(Socket, Data, Count, Verify) ->
send(Socket, Data, Count, <<>>, Verify).
%%
send(_Socket, _Data, 0, Acc, _Verify) ->
Acc;
send(Socket, Data, Count, Acc, Verify) ->
ok = ssl:send(Socket, Data),
NewAcc = Verify(Acc),
send(Socket, Data, Count - 1, NewAcc, Verify).
sender(Socket, Data) ->
ct:log("Sender recv: ~p~n", [ssl:getopts(Socket, [active])]),
<<>> =
send(
Socket, Data, 100,
fun(Acc) -> verify_recv(Socket, Data, Acc) end),
ok.
sender_active_once(Socket, Data) ->
ct:log("Sender active once: ~p~n", [ssl:getopts(Socket, [active])]),
<<>> =
send(
Socket, Data, 100,
fun(Acc) -> verify_active_once(Socket, Data, Acc) end),
ok.
sender_active(Socket, Data) ->
ct:log("Sender active: ~p~n", [ssl:getopts(Socket, [active])]),
<<>> =
send(
Socket, Data, 100,
fun(Acc) -> verify_active(Socket, Data, Acc) end),
ok.
echoer(Socket, Size) ->
ct:log("Echoer recv: ~p~n", [ssl:getopts(Socket, [active])]),
echo_recv(Socket, Size * 100).
echoer_active_once(Socket, Size) ->
ct:log("Echoer active once: ~p~n", [ssl:getopts(Socket, [active])]),
echo_active_once(Socket, Size * 100).
echoer_active(Socket, Size) ->
ct:log("Echoer active: ~p~n", [ssl:getopts(Socket, [active])]),
echo_active(Socket, Size * 100).
%% Receive Size bytes
echo_recv(Socket, Size) ->
{ok, Data} = ssl:recv(Socket, 0),
ok = ssl:send(Socket, Data),
NewSize = Size - byte_size(Data),
if
0 < NewSize ->
echo_recv(Socket, NewSize);
0 == NewSize ->
ok
end.
%% Verify that received data is SentData, return any superflous data
verify_recv(Socket, SentData, Acc) ->
{ok, NewData} = ssl:recv(Socket, 0),
SentSize = byte_size(SentData),
NewAcc = <<Acc/binary, NewData/binary>>,
NewSize = byte_size(NewAcc),
if
SentSize < NewSize ->
{SentData,Rest} = split_binary(NewAcc, SentSize),
Rest;
NewSize < SentSize ->
verify_recv(Socket, SentData, NewAcc);
true ->
SentData = NewAcc,
<<>>
end.
%% Receive Size bytes
echo_active_once(Socket, Size) ->
receive
{ssl, Socket, Data} ->
ok = ssl:send(Socket, Data),
NewSize = Size - byte_size(Data),
ssl:setopts(Socket, [{active, once}]),
if
0 < NewSize ->
echo_active_once(Socket, NewSize);
0 == NewSize ->
ok
end
end.
%% Verify that received data is SentData, return any superflous data
verify_active_once(Socket, SentData, Acc) ->
receive
{ssl, Socket, Data} ->
SentSize = byte_size(SentData),
NewAcc = <<Acc/binary, Data/binary>>,
NewSize = byte_size(NewAcc),
ssl:setopts(Socket, [{active, once}]),
if
SentSize < NewSize ->
{SentData,Rest} = split_binary(NewAcc, SentSize),
Rest;
NewSize < SentSize ->
verify_active_once(Socket, SentData, NewAcc);
true ->
SentData = NewAcc,
<<>>
end
end.
%% Receive Size bytes
echo_active(Socket, Size) ->
receive
{ssl, Socket, Data} ->
ok = ssl:send(Socket, Data),
NewSize = Size - byte_size(Data),
if
0 < NewSize ->
echo_active(Socket, NewSize);
0 == NewSize ->
ok
end
end.
%% Verify that received data is SentData, return any superflous data
verify_active(Socket, SentData, Acc) ->
receive
{ssl, Socket, Data} ->
SentSize = byte_size(SentData),
NewAcc = <<Acc/binary, Data/binary>>,
NewSize = byte_size(NewAcc),
if
SentSize < NewSize ->
{SentData,Rest} = split_binary(NewAcc, SentSize),
Rest;
NewSize < SentSize ->
verify_active(Socket, SentData, NewAcc);
true ->
SentData = NewAcc,
<<>>
end
end.
