From 3e8aa3462a151d6b528bab917bfa7b4aab021ba5 Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Fri, 14 Mar 2014 18:41:23 +0100
Subject: [snmp/agent] Fixed request id generation
When testing the agent, it is started and then used for a series
(v1, v2, v3, ...) of tests. But the individual test cases are
use one instance of the test manager. Because of this, the requerst
id cannot be a counter starting from 1 or any counter for that
matter. Instead every request id was generated using random.
But this is obiously not a guarantee fo uniqueness, it merely
makes it unlikely that the request ids will be reused.
To get around this problem (without having to rewrite the
entire agent test suite) a simple (global) counter server is
introduced. It is started at the start of the agent test suite
(init_per_suite) and stopped at the end (end_per_suite).
---
lib/snmp/test/modules.mk | 3 +-
lib/snmp/test/snmp_agent_test.erl | 13 +++
lib/snmp/test/snmp_test_mgr.erl | 3 +-
lib/snmp/test/snmp_test_mgr_counter_server.erl | 152 +++++++++++++++++++++++++
4 files changed, 169 insertions(+), 2 deletions(-)
create mode 100644 lib/snmp/test/snmp_test_mgr_counter_server.erl
(limited to 'lib/snmp')
diff --git a/lib/snmp/test/modules.mk b/lib/snmp/test/modules.mk
index 3d658bf8e8..fd8315ec4d 100644
--- a/lib/snmp/test/modules.mk
+++ b/lib/snmp/test/modules.mk
@@ -2,7 +2,7 @@
# %CopyrightBegin%
#
-# Copyright Ericsson AB 2004-2012. All Rights Reserved.
+# Copyright Ericsson AB 2004-2014. All Rights Reserved.
#
# The contents of this file are subject to the Erlang Public License,
# Version 1.1, (the "License"); you may not use this file except in
@@ -42,6 +42,7 @@ TEST_UTIL_MODULES = \
snmp_test_manager \
snmp_test_mgr \
snmp_test_mgr_misc \
+ snmp_test_mgr_counter_server \
sa \
klas3 \
test1 \
diff --git a/lib/snmp/test/snmp_agent_test.erl b/lib/snmp/test/snmp_agent_test.erl
index 84fa1af71d..a6571548d6 100644
--- a/lib/snmp/test/snmp_agent_test.erl
+++ b/lib/snmp/test/snmp_agent_test.erl
@@ -555,6 +555,8 @@ init_per_suite(Config0) when is_list(Config0) ->
Config3 = [{mib_dir, MibDir}, {std_mib_dir, StdMibDir} | Config2],
+ snmp_test_mgr_counter_server:start(),
+
?DBG("init_per_suite -> end with"
"~n Config3: ~p", [Config3]),
@@ -565,6 +567,17 @@ end_per_suite(Config) when is_list(Config) ->
?DBG("end_per_suite -> entry with"
"~n Config: ~p", [Config]),
+ case snmp_test_mgr_counter_server:stop() of
+ {ok, Counters} ->
+ ?DBG("end_per_suite -> sucessfully stopped counter server"
+ "~n Counters: ~p", [Counters]);
+
+ {error, Reason} ->
+ ?DBG("end_per_suite -> failed stopping counter server"
+ "~n Reason: ~p", [Reason])
+ end,
+
+ ?DBG("end_per_suite -> end", []),
Config.
diff --git a/lib/snmp/test/snmp_test_mgr.erl b/lib/snmp/test/snmp_test_mgr.erl
index 40fcbce8f1..d4eb00ff91 100644
--- a/lib/snmp/test/snmp_test_mgr.erl
+++ b/lib/snmp/test/snmp_test_mgr.erl
@@ -657,7 +657,8 @@ make_vb(Oid) ->
#varbind{oid = Oid, variabletype = 'NULL', value = 'NULL'}.
make_request_id() ->
- random:uniform(16#FFFFFFF-1).
+ %% random:uniform(16#FFFFFFF-1).
+ snmp_test_mgr_counter_server:increment(mgr_request_id, 1, 1, 2147483647).
echo_pdu(PDU, MiniMIB) ->
io:format("~s", [snmp_misc:format_pdu(PDU, MiniMIB)]).
diff --git a/lib/snmp/test/snmp_test_mgr_counter_server.erl b/lib/snmp/test/snmp_test_mgr_counter_server.erl
new file mode 100644
index 0000000000..db31e0380b
--- /dev/null
+++ b/lib/snmp/test/snmp_test_mgr_counter_server.erl
@@ -0,0 +1,152 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2014-2014. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+%%
+%% The reason for this (test) counter server is that the
+%% agent test suite is implemented in such a way that the
+%% agent is started once and then used for several test cases.
+%% Each request is given a request id which *was* generated using
+%% random! It is therefor possible, although unlikely, that a
+%% request may get a request id that has recently been used,
+%% which will cause the agent to silently reject the request.
+%% For this reason, we start this server at the start of the
+%% agent suite and stop it at the end and all request ids are
+%% generated by this server.
+%%
+
+-module(snmp_test_mgr_counter_server).
+
+-export([start/0, stop/0, increment/4]).
+
+-define(SERVER, ?MODULE).
+-define(TAB, snmp_test_mgr_counter_tab).
+
+
+%%%-------------------------------------------------------------------
+%%% API
+%%%-------------------------------------------------------------------
+
+-spec start() -> ok.
+
+start() ->
+ Parent = self(),
+ ReqIdServer = spawn(fun() -> init(Parent) end),
+ receive
+ {ReqIdServer, ok} ->
+ ok;
+ {ReqIdServer, {error, Reason}} ->
+ exit({failed_starting_counter_server, Reason})
+ after 5000 ->
+ exit(ReqIdServer, kill), % Cleanup, just in case
+ exit({failed_starting_counter_server, timeout})
+ end.
+
+-spec stop() -> {ok, Counters :: list()} | {error, Reason :: term()}.
+
+stop() ->
+ request(stop).
+
+
+-spec increment(Counter :: atom(),
+ Initial :: non_neg_integer(),
+ Increment :: pos_integer(),
+ Max :: pos_integer()) ->
+ Next :: pos_integer().
+
+increment(Counter, Initial, Increment, Max) ->
+ Request = {increment, Counter, Initial, Increment, Max},
+ case request(Request) of
+ {ok, ReqId} ->
+ ReqId;
+ {error, Reason} ->
+ exit(Reason)
+ end.
+
+
+request(Request) ->
+ Id = make_ref(),
+ Msg = {self(), Id, Request},
+ try
+ begin
+ global:send(?SERVER, Msg),
+ receive
+ {reply, Id, Reply} ->
+ {ok, Reply}
+ end
+ end
+ catch
+ T:E ->
+ {error, {T, E}}
+ end.
+
+
+%%%-------------------------------------------------------------------
+%%% Internal functions
+%%%-------------------------------------------------------------------
+
+init(Parent) ->
+ p("starting"),
+ case global:register_name(?SERVER, self()) of
+ yes ->
+ p("name registration ok"),
+ Parent ! {self(), ok};
+ no ->
+ p("name registration failed"),
+ Parent ! {self(), registration_failed},
+ exit(registration_failed)
+ end,
+ ets:new(?TAB, [set, named_table, {keypos, 1}]),
+ loop().
+
+loop() ->
+ receive
+ {From, Id, {increment, Counter, Initial, Increment, Max}} ->
+ Position = 2,
+ Threshold = Max,
+ SetValue = Initial,
+ UpdateOp = {Position, Increment, Threshold, SetValue},
+ NextVal =
+ try ets:update_counter(?TAB, Counter, UpdateOp) of
+ Next when is_integer(Next) ->
+ p("increment ~w: (next) ~w", [Counter, Next]),
+ Next
+ catch
+ error:badarg ->
+ %% Oups, first time
+ p("increment ~w: (initial) ~w", [Counter, Initial]),
+ ets:insert(?TAB, {Counter, Initial}),
+ Initial
+ end,
+ From ! {reply, Id, NextVal},
+ loop();
+
+ {From, Id, stop} ->
+ p("stop"),
+ Counters = ets:tab2list(?TAB),
+ From ! {reply, Id, Counters},
+ exit(normal)
+ end.
+
+
+p(F) ->
+ p(F, []).
+
+p(F, A) ->
+ io:format("*** [~s] COUNTER-SERVER [~w] " ++ F ++ "~n",
+ [snmp_test_lib:formated_timestamp(), self() | A]).
--
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