[snmp/manager] Introduced new net-if module

Moved the net-if multi-threading to a separate module,
snmpm_net_if_mt. Restored the old module to its previous
state.

OTP-9876

5 files changed, 1221 insertions, 6 deletions

diff --git a/lib/snmp/src/app/snmp.app.src b/lib/snmp/src/app/snmp.app.src
index a880a14696..7fb76baaa5 100644
--- a/lib/snmp/src/app/snmp.app.src
+++ b/lib/snmp/src/app/snmp.app.src
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1996-2009. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2012. 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
@@ -90,6 +90,7 @@
              snmpm_misc_sup,
              snmpm_mpd,
              snmpm_net_if,
+             snmpm_net_if_mt,
              snmpm_net_if_filter,
              snmpm_network_interface,
              snmpm_network_interface_filter,
diff --git a/lib/snmp/src/manager/depend.mk b/lib/snmp/src/manager/depend.mk
index 0e7e9e3df7..2e7783c8ed 100644
--- a/lib/snmp/src/manager/depend.mk
+++ b/lib/snmp/src/manager/depend.mk
@@ -2,7 +2,7 @@
 
 # %CopyrightBegin%
 # 
-# Copyright Ericsson AB 2004-2009. All Rights Reserved.
+# Copyright Ericsson AB 2004-2012. 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
@@ -49,6 +49,13 @@ $(EBIN)/snmpm_net_if.$(EMULATOR): \
 	snmpm_net_if.erl \
 	snmpm_network_interface.erl
 
+$(EBIN)/snmpm_net_if_mt.$(EMULATOR): \
+	../../include/snmp_types.hrl \
+	../misc/snmp_debug.hrl \
+	../misc/snmp_verbosity.hrl \
+	snmpm_net_if_mt.erl \
+	snmpm_network_interface.erl
+
 $(EBIN)/snmpm_server.$(EMULATOR): \
 	../../include/snmp_types.hrl \
 	../../include/STANDARD-MIB.hrl \
diff --git a/lib/snmp/src/manager/modules.mk b/lib/snmp/src/manager/modules.mk
index 79f3dd65d9..d46545ea3f 100644
--- a/lib/snmp/src/manager/modules.mk
+++ b/lib/snmp/src/manager/modules.mk
@@ -2,7 +2,7 @@
 
 # %CopyrightBegin%
 # 
-# Copyright Ericsson AB 2004-2009. All Rights Reserved.
+# Copyright Ericsson AB 2004-2012. 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
@@ -31,6 +31,7 @@ MODULES = \
 	snmpm_mpd \
 	snmpm_misc_sup \
 	snmpm_net_if \
+	snmpm_net_if_mt \
 	snmpm_net_if_filter \
 	snmpm_server \
 	snmpm_server_sup \
diff --git a/lib/snmp/src/manager/snmpm_mpd.erl b/lib/snmp/src/manager/snmpm_mpd.erl
index 103c87d32b..883224143e 100644
--- a/lib/snmp/src/manager/snmpm_mpd.erl
+++ b/lib/snmp/src/manager/snmpm_mpd.erl
@@ -110,9 +110,9 @@ process_msg(Msg, Domain, Addr, Port, State, NoteStore, Logger) ->
 	#message{version = 'version-2', vsn_hdr = Community, data = Data}
 	  when State#state.v2c =:= true ->
 	    HS = ?empty_msg_size + length(Community),
-	    (catch process_v1_v2c_msg('version-2', NoteStore, Msg, 
-				      Domain, Addr, Port, 
-				      Community, Data, HS, Logger));
+	    process_v1_v2c_msg('version-2', NoteStore, Msg, 
+			       Domain, Addr, Port, 
+			       Community, Data, HS, Logger);
 	     
 	%% Version 3
 	#message{version = 'version-3', vsn_hdr = H, data = Data}
diff --git a/lib/snmp/src/manager/snmpm_net_if_mt.erl b/lib/snmp/src/manager/snmpm_net_if_mt.erl
new file mode 100644
index 0000000000..93b21af1d7
--- /dev/null
+++ b/lib/snmp/src/manager/snmpm_net_if_mt.erl
@@ -0,0 +1,1206 @@
+%% 
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2004-2012. 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%
+%% 
+
+-module(snmpm_net_if_mt).
+
+-behaviour(gen_server).
+-behaviour(snmpm_network_interface).
+
+
+%% Network Interface callback functions
+-export([
+	 start_link/2, 
+	 stop/1, 
+	 send_pdu/6, % Backward compatibillity
+	 send_pdu/7, % Backward compatibillity
+	 send_pdu/8,
+
+	 inform_response/4, 
+
+	 note_store/2, 
+
+	 info/1, 
+ 	 verbosity/2, 
+ 	 %% system_info_updated/2, 
+ 	 get_log_type/1, set_log_type/2,
+	 filter_reset/1
+	]).
+
+%% gen_server callbacks
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2, 
+	 code_change/3, terminate/2]).
+
+-define(SNMP_USE_V3, true).
+-include("snmp_types.hrl").
+-include("snmpm_internal.hrl").
+-include("snmpm_atl.hrl").
+-include("snmp_debug.hrl").
+
+%% -define(VMODULE,"NET_IF").
+-include("snmp_verbosity.hrl").
+
+-record(state, 
+	{
+	  server,
+	  note_store,
+	  sock, 
+	  mpd_state,
+	  logger,     % undefined | pid()
+	  irb = auto, % auto | {user, integer()}
+	  irgc,
+	  filter
+	 }).
+
+
+-define(DEFAULT_FILTER_MODULE, snmpm_net_if_filter).
+-define(DEFAULT_FILTER_OPTS,   [{module, ?DEFAULT_FILTER_MODULE}]).
+
+-ifdef(snmp_debug).
+-define(GS_START_LINK(Args),
+	gen_server:start_link(?MODULE, Args, [{debug,[trace]}])).
+-else.
+-define(GS_START_LINK(Args),
+	gen_server:start_link(?MODULE, Args, [])).
+-endif.
+
+
+-define(IRGC_TIMEOUT, timer:minutes(5)).
+
+-define(ATL_SEQNO_INITIAL, 1).
+-define(ATL_SEQNO_MAX,     2147483647).
+
+
+%%%-------------------------------------------------------------------
+%%% API
+%%%-------------------------------------------------------------------
+start_link(Server, NoteStore) ->
+    ?d("start_link -> entry with"
+       "~n   Server:    ~p"
+       "~n   NoteStore: ~p", [Server, NoteStore]),
+    Args = [Server, NoteStore], 
+    ?GS_START_LINK(Args).
+
+stop(Pid) ->
+    call(Pid, stop).
+
+send_pdu(Pid, Pdu, Vsn, MsgData, Addr, Port) ->
+    send_pdu(Pid, Pdu, Vsn, MsgData, Addr, Port, ?DEFAULT_EXTRA_INFO).
+
+send_pdu(Pid, Pdu, Vsn, MsgData, Addr, Port, ExtraInfo) ->
+    Domain = snmpm_config:default_transport_domain(), 
+    send_pdu(Pid, Pdu, Vsn, MsgData, Domain, Addr, Port, ExtraInfo).
+
+send_pdu(Pid, Pdu, Vsn, MsgData, Domain, Addr, Port, ExtraInfo) 
+  when is_record(Pdu, pdu) ->
+    ?d("send_pdu -> entry with"
+       "~n   Pid:     ~p"
+       "~n   Pdu:     ~p"
+       "~n   Vsn:     ~p"
+       "~n   MsgData: ~p"
+       "~n   Domain:  ~p"
+       "~n   Addr:    ~p"
+       "~n   Port:    ~p", [Pid, Pdu, Vsn, MsgData, Domain, Addr, Port]),
+    cast(Pid, {send_pdu, Pdu, Vsn, MsgData, Domain, Addr, Port, ExtraInfo}).
+
+note_store(Pid, NoteStore) ->
+    call(Pid, {note_store, NoteStore}).
+
+inform_response(Pid, Ref, Addr, Port) ->
+    cast(Pid, {inform_response, Ref, Addr, Port}).
+
+info(Pid) ->
+    call(Pid, info).
+
+verbosity(Pid, V) ->
+    call(Pid, {verbosity, V}).
+
+%% system_info_updated(Pid, What) ->
+%%     call(Pid, {system_info_updated, What}).
+
+get_log_type(Pid) ->
+    call(Pid, get_log_type).
+
+set_log_type(Pid, NewType) ->
+    call(Pid, {set_log_type, NewType}).
+
+filter_reset(Pid) ->
+    cast(Pid, filter_reset).
+
+
+%%%-------------------------------------------------------------------
+%%% Callback functions from gen_server
+%%%-------------------------------------------------------------------
+
+%%--------------------------------------------------------------------
+%% Func: init/1
+%% Returns: {ok, State}          |
+%%          {ok, State, Timeout} |
+%%          ignore               |
+%%          {stop, Reason}
+%%--------------------------------------------------------------------
+init([Server, NoteStore]) -> 
+    ?d("init -> entry with"
+       "~n   Server:    ~p"
+       "~n   NoteStore: ~p", [Server, NoteStore]),
+    case (catch do_init(Server, NoteStore)) of
+	{error, Reason} ->
+	    {stop, Reason};
+	{ok, State} ->
+	    {ok, State}
+    end.
+	    
+do_init(Server, NoteStore) ->
+    process_flag(trap_exit, true),
+
+    %% -- Prio --
+    {ok, Prio} = snmpm_config:system_info(prio),
+    process_flag(priority, Prio),
+
+    %% -- Create inform request table --
+    ets:new(snmpm_inform_request_table,
+	    [set, protected, named_table, {keypos, 1}]),
+
+    %% -- Verbosity -- 
+    {ok, Verbosity} = snmpm_config:system_info(net_if_verbosity),
+    put(sname,mnif),
+    put(verbosity,Verbosity),
+    ?vlog("starting", []),
+
+    %% -- MPD --
+    {ok, Vsns} = snmpm_config:system_info(versions),
+    MpdState   = snmpm_mpd:init(Vsns),
+
+    %% -- Module dependent options --
+    {ok, Opts} = snmpm_config:system_info(net_if_options),
+
+    %% -- Inform response behaviour --
+    {ok, IRB}  = snmpm_config:system_info(net_if_irb), 
+    IrGcRef    = irgc_start(IRB), 
+
+    %% -- Socket --
+    SndBuf  = get_opt(Opts, sndbuf,       default),
+    RecBuf  = get_opt(Opts, recbuf,       default),
+    BindTo  = get_opt(Opts, bind_to,      false),
+    NoReuse = get_opt(Opts, no_reuse,     false),
+    {ok, Port} = snmpm_config:system_info(port),
+    {ok, Sock} = do_open_port(Port, SndBuf, RecBuf, BindTo, NoReuse),
+
+    %% Flow control --
+    FilterOpts = get_opt(Opts, filter, []),
+    FilterMod  = create_filter(FilterOpts),
+    ?vdebug("FilterMod: ~w", [FilterMod]),
+
+    %% -- Audit trail log ---
+    {ok, ATL} = snmpm_config:system_info(audit_trail_log),
+    Log = do_init_log(ATL),
+
+    %% -- Initiate counters ---
+    init_counters(),
+    
+    %% -- We are done ---
+    State = #state{server     = Server, 
+		   note_store = NoteStore, 
+		   mpd_state  = MpdState,
+		   sock       = Sock, 
+		   log        = Log,
+		   irb        = IRB,
+		   irgc       = IrGcRef,
+		   filter     = FilterMod},
+    ?vdebug("started", []),
+    {ok, State}.
+
+
+%% Open port 
+do_open_port(Port, SendSz, RecvSz, BindTo, NoReuse) ->
+    ?vtrace("do_open_port -> entry with"
+	    "~n   Port:    ~p"
+	    "~n   SendSz:  ~p"
+	    "~n   RecvSz:  ~p"
+	    "~n   BindTo:  ~p"
+	    "~n   NoReuse: ~p", [Port, SendSz, RecvSz, BindTo, NoReuse]),
+    IpOpts1 = bind_to(BindTo),
+    IpOpts2 = no_reuse(NoReuse),
+    IpOpts3 = recbuf(RecvSz),
+    IpOpts4 = sndbuf(SendSz),
+    IpOpts  = [binary | IpOpts1 ++ IpOpts2 ++ IpOpts3 ++ IpOpts4],
+    OpenRes = 
+	case init:get_argument(snmpm_fd) of
+	    {ok, [[FdStr]]} ->
+		Fd = list_to_integer(FdStr),
+		gen_udp:open(0, [{fd, Fd}|IpOpts]);
+	    error ->
+		gen_udp:open(Port, IpOpts)
+	end,
+    case OpenRes of
+	{error, _} = Error ->
+	    throw(Error);
+	OK ->
+	    OK
+    end.
+
+bind_to(true) ->
+    case snmpm_config:system_info(address) of
+	{ok, Addr} when is_list(Addr) ->
+	    [{ip, list_to_tuple(Addr)}];
+	{ok, Addr} ->
+	    [{ip, Addr}];
+	_ ->
+	    []
+    end;
+bind_to(_) ->
+    [].
+
+no_reuse(false) ->
+    [{reuseaddr, true}];
+no_reuse(_) ->
+    [].
+
+recbuf(default) ->
+    [];
+recbuf(Sz) ->
+    [{recbuf, Sz}].
+
+sndbuf(default) ->
+    [];
+sndbuf(Sz) ->
+    [{sndbuf, Sz}].
+
+
+create_filter(Opts) when is_list(Opts) ->
+    case get_opt(Opts, module, ?DEFAULT_FILTER_MODULE) of
+	?DEFAULT_FILTER_MODULE = Mod ->
+	    Mod;
+	Module ->
+	    snmpm_network_interface_filter:verify(Module),
+	    Module
+    end;
+create_filter(BadOpts) ->
+    throw({error, {bad_filter_opts, BadOpts}}).
+
+
+%% ----------------------------------------------------------------------
+%%                         Audit Trail Logger
+%% ----------------------------------------------------------------------
+
+%% Open log
+do_init_log(false) ->
+    ?vtrace("do_init_log(false) -> entry", []),
+    undefined;
+do_init_log(true) ->
+    ?vtrace("do_init_log(true) -> entry", []),
+    logger_start().
+
+logger_start() ->
+    {Pid, _} = Logger = 
+	erlang:spawn_opt(?MODULE, logger_init, [self()], [monitor]),
+    receive
+	{logger_started, Pid} ->
+	    {ok, Type} = snmpm_config:system_info(audit_trail_log_type),
+	    {Logger, Type};
+	{'DOWN', _MonitorRef, process, Pid, Reason} ->
+	    throw({error, {failed_starting_logger, Logger, Reason}})
+    after 5000 ->
+	    %% This should really not take any time at all, 
+	    %% so 5 secs is plenty of time.
+	    throw({error, {failed_starting_logger, Logger, timeout})
+    end.
+	
+logger_init(Parent) ->
+    case (catch do_logger_init()) of
+	{ok, Log} ->
+	    Parent ! {logger_started, self()}, 
+	    logger_loop(#logger{parent = Parent, 
+				log    = Log});
+	{error, Reason} ->
+	    exit({failed_init_log, Reason})
+    end.
+
+%% Open log
+do_logger_init() ->
+    ?vtrace("do_logger_init() -> entry", []),
+    {ok, Dir}    = snmpm_config:system_info(audit_trail_log_dir),
+    {ok, Size}   = snmpm_config:system_info(audit_trail_log_size),
+    {ok, Repair} = snmpm_config:system_info(audit_trail_log_repair),
+    Name = ?audit_trail_log_name, 
+    File = filename:absname(?audit_trail_log_file, Dir),
+    case snmpm_config:system_info(audit_trail_log_seqno) of
+	{ok, true} ->
+	    Initial  = ?ATL_SEQNO_INITIAL,
+	    Max      = ?ATL_SEQNO_MAX, 
+	    Module   = snmpm_config, 
+	    Function = increment_counter, 
+	    Args     = [atl_seqno, Initial, Max], 
+	    SeqNoGen = {Module, Function, Args}, 
+	    case snmp_log:create(Name, File, SeqNoGen, Size, Repair, true) of
+		{ok, Log} ->
+		    ?vdebug("log created: ~w", [Log]),
+		    {ok, Log};
+		{error, Reason} ->
+		    {error, {failed_create_audit_log, Reason}}
+	    end;
+	_ ->
+	    case snmp_log:create(Name, File, Size, Repair, true) of
+		{ok, Log} ->
+		    ?vdebug("log created: ~w", [Log]),
+		    {ok, Log};
+		{error, Reason} ->
+		    {error, {failed_create_audit_log, Reason}}
+	    end
+    end.
+
+
+logger_loop(Logger) ->
+    receive
+	{log, Msg, Addr, Port} ->
+	    snmp_log:log(Logger#logger.log, Msg, Addr, Port);
+	{stop, Pid} when Pid =:= Logger#logger.parent ->
+	    exit(normal)
+    end,
+    logger_loop(Logger).
+
+
+%% ----------------------------------------------------------------------
+
+    
+%%--------------------------------------------------------------------
+%% Func: handle_call/3
+%% Returns: {reply, Reply, State}          |
+%%          {reply, Reply, State, Timeout} |
+%%          {noreply, State}               |
+%%          {noreply, State, Timeout}      |
+%%          {stop, Reason, Reply, State}   | (terminate/2 is called)
+%%          {stop, Reason, State}            (terminate/2 is called)
+%%--------------------------------------------------------------------
+handle_call({verbosity, Verbosity}, _From, State) ->
+    ?vlog("received verbosity request", []),
+    put(verbosity, Verbosity),
+    {reply, ok, State};
+
+%% handle_call({system_info_updated, What}, _From, State) ->
+%%     ?vlog("received system_info_updated request with What = ~p", [What]),
+%%     {NewState, Reply} = handle_system_info_updated(State, What),
+%%     {reply, Reply, NewState};
+
+handle_call(get_log_type, _From, State) ->
+    ?vlog("received get-log-type request", []),
+    Reply = (catch handle_get_log_type(State)),
+    {reply, Reply, State};
+
+handle_call({set_log_type, NewType}, _From, State) ->
+    ?vlog("received set-log-type request with NewType = ~p", [NewType]),
+    {NewState, Reply} = (catch handle_set_log_type(State, NewType)),
+    {reply, Reply, NewState};
+
+handle_call({note_store, Pid}, _From, State) ->
+    ?vlog("received new note_store: ~w", [Pid]),
+    {reply, ok, State#state{note_store = Pid}};
+
+handle_call(stop, _From, State) ->
+    ?vlog("received stop request", []),
+    Reply = ok,
+    {stop, normal, Reply, State};
+
+handle_call(info, _From, State) ->
+    ?vlog("received info request", []),
+    Reply = get_info(State),
+    {reply, Reply, State};
+
+handle_call(Req, From, State) ->
+    warning_msg("received unknown request (from ~p): ~n~p", [Req, From]),
+    {reply, {error, {invalid_request, Req}}, State}.
+
+
+%%--------------------------------------------------------------------
+%% Func: handle_cast/2
+%% Returns: {noreply, State}          |
+%%          {noreply, State, Timeout} |
+%%          {stop, Reason, State}            (terminate/2 is called)
+%%--------------------------------------------------------------------
+handle_cast({send_pdu, Pdu, Vsn, MsgData, Domain, Addr, Port, ExtraInfo}, 
+	    State) ->
+    ?vlog("received send_pdu message with"
+	  "~n   Pdu:     ~p"
+	  "~n   Vsn:     ~p"
+	  "~n   MsgData: ~p"
+	  "~n   Domain:  ~p"
+	  "~n   Addr:    ~p"
+	  "~n   Port:    ~p", [Pdu, Vsn, MsgData, Domain, Addr, Port]),
+    maybe_process_extra_info(ExtraInfo), 
+    maybe_handle_send_pdu(Pdu, Vsn, MsgData, Domain, Addr, Port, State), 
+    {noreply, State};
+
+handle_cast({inform_response, Ref, Addr, Port}, State) ->
+    ?vlog("received inform_response message with"
+	  "~n   Ref:  ~p"
+	  "~n   Addr: ~p"
+	  "~n   Port: ~p", [Ref, Addr, Port]),
+    handle_inform_response(Ref, Addr, Port, State), 
+    {noreply, State};
+
+handle_cast(filter_reset, State) ->
+    ?vlog("received filter_reset message", []),
+    reset_counters(),
+    {noreply, State};
+
+handle_cast(Msg, State) ->
+    warning_msg("received unknown message: ~n~p", [Msg]),
+    {noreply, State}.
+
+
+%%--------------------------------------------------------------------
+%% Func: handle_info/2
+%% Returns: {noreply, State}          |
+%%          {noreply, State, Timeout} |
+%%          {stop, Reason, State}            (terminate/2 is called)
+%%--------------------------------------------------------------------
+handle_info({udp, Sock, Ip, Port, Bytes}, State) ->
+    ?vlog("received ~w bytes from ~p:~p", [size(Bytes), Ip, Port]),
+    handle_udp(Sock, Ip, Port, Bytes, State),
+    {noreply, State};
+
+handle_info(inform_response_gc, State) ->
+    ?vlog("received inform_response_gc message", []),
+    State2 = handle_inform_response_gc(State),
+    {noreply, State2};
+
+handle_info({disk_log, _Node, Log, Info}, State) ->
+    ?vlog("received disk_log message: "
+	  "~n   Info: ~p", [Info]),
+    State2 = handle_disk_log(Log, Info, State),
+    {noreply, State2};
+
+handle_info(Info, State) ->
+    warning_msg("received unknown info: ~n~p", [Info]),
+    {noreply, State}.
+
+
+%%--------------------------------------------------------------------
+%% Func: terminate/2
+%% Purpose: Shutdown the server
+%% Returns: any (ignored by gen_server)
+%%--------------------------------------------------------------------
+terminate(Reason, #state{log = Log, irgc = IrGcRef}) ->
+    ?vdebug("terminate: ~p", [Reason]),
+    irgc_stop(IrGcRef),
+    %% Close logs
+    do_close_log(Log),
+    ok.
+
+
+do_close_log({Log, _Type}) ->
+    (catch snmp_log:sync(Log)),
+    (catch snmp_log:close(Log)),
+    ok;
+do_close_log(_) ->
+    ok.
+
+
+%%----------------------------------------------------------------------
+%% Func: code_change/3
+%% Purpose: Convert process state when code is changed
+%% Returns: {ok, NewState}
+%%----------------------------------------------------------------------
+ 
+code_change(_Vsn, State, _Extra) ->
+    ?d("code_change -> entry with"
+       "~n   Vsn:   ~p"
+       "~n   State: ~p"
+       "~n   Extra: ~p", [_Vsn, State, _Extra]),
+    {ok, State}.
+
+ 
+%%%-------------------------------------------------------------------
+%%% Internal functions
+%%%-------------------------------------------------------------------
+
+handle_udp(Sock, Addr, Port, Bytes, State) ->
+    spawn_opt(fun() -> 
+		      maybe_handle_recv_msg(Addr, Port, Bytes, State) 
+	      end, 
+	      [monitor]).
+    
+
+maybe_handle_recv_msg(Addr, Port, Bytes, #state{filter = FilterMod} = State) ->
+    case (catch FilterMod:accept_recv(Addr, Port)) of
+	false ->
+	    %% Drop the received packet 
+	    inc(netIfMsgInDrops),
+	    ok;
+	_ ->
+	    handle_recv_msg(Addr, Port, Bytes, State)
+    end.
+    
+
+handle_recv_msg(Addr, Port, Bytes, #state{server = Pid}) 
+  when is_binary(Bytes) andalso (size(Bytes) =:= 0) ->
+    Pid ! {snmp_error, {empty_message, Addr, Port}, Addr, Port},
+    ok;
+
+handle_recv_msg(Addr, Port, Bytes, 
+		#state{server     = Pid, 
+		       note_store = NoteStore, 
+		       mpd_state  = MpdState, 
+		       sock       = Sock,
+		       log        = Log} = State) ->
+    Domain = snmp_conf:which_domain(Addr), % What the ****...
+    Logger = logger(Log, read, Addr, Port), 
+    case (catch snmpm_mpd:process_msg(Bytes, Domain, Addr, Port, 
+				      MpdState, NoteStore, Logger)) of
+
+	{ok, Vsn, Pdu, MS, ACM} ->
+	    maybe_handle_recv_pdu(Addr, Port, Vsn, Pdu, MS, ACM, 
+				  Logger, State);
+
+	{discarded, Reason, Report} ->
+	    ?vdebug("discarded: ~p", [Reason]),
+	    ErrorInfo = {failed_processing_message, Reason},
+	    Pid ! {snmp_error, ErrorInfo, Addr, Port},
+	    maybe_udp_send(State#state.filter, Sock, Addr, Port, Report),
+	    ok;
+
+	{discarded, Reason} ->
+	    ?vdebug("discarded: ~p", [Reason]),
+	    ErrorInfo = {failed_processing_message, Reason},
+	    Pid ! {snmp_error, ErrorInfo, Addr, Port},
+	    ok;
+
+	Error ->
+	    error_msg("processing of received message failed: "
+		      "~n   ~p", [Error]),
+	    ok
+    end.
+
+
+maybe_handle_recv_pdu(Addr, Port, 
+		      Vsn, #pdu{type = Type} = Pdu, PduMS, ACM, 
+		      Logger, 
+		      #state{filter = FilterMod} = State) ->
+    case (catch FilterMod:accept_recv_pdu(Addr, Port, Type)) of
+	false ->
+	    inc(netIfPduInDrops),
+	    ok;
+	_ ->
+	    handle_recv_pdu(Addr, Port, Vsn, Pdu, PduMS, ACM, Logger, State)
+    end;
+maybe_handle_recv_pdu(Addr, Port, Vsn, Trap, PduMS, ACM, Logger, 
+		      #state{filter = FilterMod} = State) 
+  when is_record(Trap, trappdu) ->
+    case (catch FilterMod:accept_recv_pdu(Addr, Port, trappdu)) of
+	false ->
+	    inc(netIfPduInDrops),
+	    ok;
+	_ ->
+	    handle_recv_pdu(Addr, Port, Vsn, Trap, PduMS, ACM, Logger, State)
+    end;
+maybe_handle_recv_pdu(Addr, Port, Vsn, Pdu, PduMS, ACM, Logger, State) ->
+    handle_recv_pdu(Addr, Port, Vsn, Pdu, PduMS, ACM, Logger, State).
+
+
+handle_recv_pdu(Addr, Port, 
+		Vsn, #pdu{type = 'inform-request'} = Pdu, _PduMS, ACM, 
+		Logger, #state{server = Pid, irb = IRB} = State) ->
+    handle_inform_request(IRB, Pid, Vsn, Pdu, ACM, 
+			  Addr, Port, Logger, State);
+handle_recv_pdu(Addr, Port, 
+		_Vsn, #pdu{type = report} = Pdu, _PduMS, ok, 
+		_Logger, 
+		#state{server = Pid} = _State) ->
+    ?vtrace("received report - ok", []),
+    Pid ! {snmp_report, {ok, Pdu}, Addr, Port};
+handle_recv_pdu(Addr, Port, 
+		_Vsn, #pdu{type = report} = Pdu, _PduMS, 
+		{error, ReqId, Reason}, 
+		_Logger, 
+		#state{server = Pid} = _State) ->
+    ?vtrace("received report - error", []),
+    Pid ! {snmp_report, {error, ReqId, Reason, Pdu}, Addr, Port};
+handle_recv_pdu(Addr, Port, 
+		_Vsn, #pdu{type = 'snmpv2-trap'} = Pdu, _PduMS, _ACM, 
+		_Logger, 
+		#state{server = Pid} = _State) ->
+    ?vtrace("received snmpv2-trap", []),
+    Pid ! {snmp_trap, Pdu, Addr, Port};
+handle_recv_pdu(Addr, Port, 
+		_Vsn, Trap, _PduMS, _ACM, 
+		_Logger, 
+		#state{server = Pid} = _State) when is_record(Trap, trappdu) ->
+    ?vtrace("received trappdu", []),
+    Pid ! {snmp_trap, Trap, Addr, Port};
+handle_recv_pdu(Addr, Port, 
+		_Vsn, Pdu, _PduMS, _ACM, 
+		_Logger, 
+		#state{server = Pid} = _State) when is_record(Pdu, pdu) ->
+    ?vtrace("received pdu", []),
+    Pid ! {snmp_pdu, Pdu, Addr, Port};
+handle_recv_pdu(_Addr, _Port, _Vsn, Pdu, _PduMS, ACM, _Logger, _State) ->
+    ?vlog("received unexpected pdu: "
+	    "~n   Pdu: ~p"
+	    "~n   ACM: ~p", [Pdu, ACM]).
+
+
+handle_inform_request(auto, Pid, Vsn, Pdu, ACM, Addr, Port, Logger, State) ->
+    ?vtrace("received inform-request (true)", []),
+    Pid ! {snmp_inform, ignore, Pdu, Addr, Port},
+    RePdu = make_response_pdu(Pdu),
+    maybe_send_inform_response(RePdu, Vsn, ACM, Addr, Port, Logger, State);
+handle_inform_request({user, To}, Pid, Vsn, #pdu{request_id = ReqId} = Pdu, 
+		      ACM, Addr, Port, _Logger, _State) ->
+    ?vtrace("received inform-request (false)", []),
+
+    Pid ! {snmp_inform, ReqId, Pdu, Addr, Port},
+
+    %% Before we go any further, we need to check that we have not
+    %% already received this message (possible resend).
+
+    Key = {ReqId, Addr, Port},
+    case ets:lookup(snmpm_inform_request_table, Key) of
+	[_] ->
+	    %% OK, we already know about this.  We assume this
+	    %% is a resend. Either the agent is really eager or
+	    %% the user has not answered yet. Bad user!
+	    ok;
+	[] ->
+	    RePdu  = make_response_pdu(Pdu),
+	    Expire = t() + To, 
+	    Rec    = {Key, Expire, {Vsn, ACM, RePdu}},
+	    ets:insert(snmpm_inform_request_table, Rec)
+    end.
+	    
+handle_inform_response(Ref, Addr, Port, State) ->
+    Key = {Ref, Addr, Port},
+    case ets:lookup(snmpm_inform_request_table, Key) of
+	[{Key, _, {Vsn, ACM, RePdu}}] ->
+	    Logger = logger(State#state.log, read, Addr, Port),
+	    ets:delete(snmpm_inform_request_table, Key), 
+	    maybe_send_inform_response(RePdu, Vsn, ACM, Addr, Port, 
+				       Logger, State);
+	[] ->
+	    %% Already acknowledged, or the user was to slow to reply...
+	    ok
+    end,
+    ok.
+
+maybe_send_inform_response(RePdu, Vsn, ACM, Addr, Port, Logger, 
+			   #state{server = Pid, 
+				  sock   = Sock, 
+				  filter = FilterMod}) ->
+    case (catch FilterMod:accept_send_pdu(Addr, Port, pdu_type_of(RePdu))) of
+	false ->
+	    inc(netIfPduOutDrops),
+	    ok;
+	_ ->
+	    case snmpm_mpd:generate_response_msg(Vsn, RePdu, ACM, Logger) of
+		{ok, Msg} ->
+		    maybe_udp_send(FilterMod, Sock, Addr, Port, Msg);
+		{discarded, Reason} ->
+		    ?vlog("failed generating response message:"
+			  "~n   Reason: ~p", [Reason]),
+		    ReqId     = RePdu#pdu.request_id,
+		    ErrorInfo = {failed_generating_response, {RePdu, Reason}},
+		    Pid ! {snmp_error, ReqId, ErrorInfo, Addr, Port},
+		    ok
+	    end
+    end.
+    
+handle_inform_response_gc(#state{irb = IRB} = State) ->
+    ets:safe_fixtable(snmpm_inform_request_table, true),
+    do_irgc(ets:first(snmpm_inform_request_table), t()),
+    ets:safe_fixtable(snmpm_inform_request_table, false),
+    State#state{irgc = irgc_start(IRB)}.
+
+%% We are deleting at the same time as we are traversing the table!!!
+do_irgc('$end_of_table', _) ->
+    ok;
+do_irgc(Key, Now) ->
+    Next = ets:next(snmpm_inform_request_table, Key),
+    case ets:lookup(snmpm_inform_request_table, Key) of
+        [{Key, BestBefore, _}] when BestBefore < Now ->
+            ets:delete(snmpm_inform_request_table, Key);
+        _ ->
+            ok
+    end,
+    do_irgc(Next, Now).
+
+irgc_start(auto) ->
+    undefined;
+irgc_start(_) ->
+    erlang:send_after(?IRGC_TIMEOUT, self(), inform_response_gc).
+
+irgc_stop(undefined) ->
+    ok;
+irgc_stop(Ref) ->
+    (catch erlang:cancel_timer(Ref)).
+
+
+handle_send_pdu(Pdu, Vsn, MsgData, Domain, Addr, Port, State) ->
+    spawn_opt(fun() -> 
+		      maybe_handle_send_pdu(Pdu, Vsn, MsgData, 
+					    Domain, Addr, Port, 
+					    State)
+	      end, 
+	      [monitor]).
+
+maybe_handle_send_pdu(Pdu, Vsn, MsgData, Domain, Addr, Port, 
+		      #state{filter = FilterMod} = State) ->
+    case (catch FilterMod:accept_send_pdu(Addr, Port, pdu_type_of(Pdu))) of
+	false ->
+	    inc(netIfPduOutDrops),
+	    ok;
+	_ ->
+	    do_handle_send_pdu(Pdu, Vsn, MsgData, Domain, Addr, Port, State)
+    end.
+
+do_handle_send_pdu(Pdu, Vsn, MsgData, _Domain, Addr, Port, 
+		#state{server     = Pid, 
+		       note_store = NoteStore, 
+		       sock       = Sock, 
+		       log        = Log,
+		       filter     = FilterMod}) ->
+    Logger = logger(Log, write, Addr, Port),
+    case (catch snmpm_mpd:generate_msg(Vsn, NoteStore, 
+				       Pdu, MsgData, Logger)) of
+	{ok, Msg} ->
+	    ?vtrace("handle_send_pdu -> message generated", []),
+	    maybe_udp_send(FilterMod, Sock, Addr, Port, Msg);	    
+	{discarded, Reason} ->
+	    ?vlog("PDU not sent: "
+		  "~n   PDU:    ~p"
+		  "~n   Reason: ~p", [Pdu, Reason]),
+	    Pid ! {snmp_error, Pdu, Reason},
+	    ok
+    end.
+
+
+maybe_udp_send(FilterMod, Sock, Addr, Port, Msg) ->
+    case (catch FilterMod:accept_send(Addr, Port)) of
+	false ->
+	    inc(netIfMsgOutDrops),
+	    ok;
+	_ ->
+	    udp_send(Sock, Addr, Port, Msg)
+    end.
+	    
+    
+udp_send(Sock, Addr, Port, Msg) ->
+    case (catch gen_udp:send(Sock, Addr, Port, Msg)) of
+	ok ->
+	    ?vdebug("sent ~w bytes to ~w:~w [~w]", 
+		    [sz(Msg), Addr, Port, Sock]),
+	    ok;
+	{error, Reason} ->
+	    error_msg("failed sending message to ~p:~p: "
+		      "~n   ~p",[Addr, Port, Reason]);
+	Error ->
+	    error_msg("failed sending message to ~p:~p: "
+		      "~n   ~p",[Addr, Port, Error])
+    end.
+
+sz(B) when is_binary(B) ->
+    size(B);
+sz(L) when is_list(L) ->
+    length(L);
+sz(_) ->
+    undefined.
+
+
+handle_disk_log(_Log, {wrap, NoLostItems}, State) ->
+    ?vlog("Audit Trail Log - wrapped: ~w previously logged items where lost", 
+	  [NoLostItems]),
+    State;
+handle_disk_log(_Log, {truncated, NoLostItems}, State) ->
+    ?vlog("Audit Trail Log - truncated: ~w items where lost when truncating", 
+	  [NoLostItems]),
+    State;
+handle_disk_log(_Log, full, State) ->
+    error_msg("Failed to write to Audit Trail Log (full)", []),
+    State;
+handle_disk_log(_Log, {error_status, ok}, State) ->
+    State;
+handle_disk_log(_Log, {error_status, {error, Reason}}, State) ->
+    error_msg("Error status received from Audit Trail Log: "
+	      "~n~p", [Reason]),
+    State;
+handle_disk_log(_Log, _Info, State) ->
+    State.
+
+
+%% mk_discovery_msg('version-3', Pdu, _VsnHdr, UserName) ->
+%%     ScopedPDU = #scopedPdu{contextEngineID = "",
+%% 			   contextName = "",
+%% 			   data = Pdu},
+%%     Bytes = snmp_pdus:enc_scoped_pdu(ScopedPDU),
+%%     MsgID = get(msg_id),
+%%     put(msg_id,MsgID+1),
+%%     UsmSecParams = 
+%% 	#usmSecurityParameters{msgAuthoritativeEngineID = "",
+%% 			       msgAuthoritativeEngineBoots = 0,
+%% 			       msgAuthoritativeEngineTime = 0,
+%% 			       msgUserName = UserName,
+%% 			       msgPrivacyParameters = "",
+%% 			       msgAuthenticationParameters = ""},
+%%     SecBytes = snmp_pdus:enc_usm_security_parameters(UsmSecParams),
+%%     PduType = Pdu#pdu.type,
+%%     Hdr = #v3_hdr{msgID = MsgID, 
+%% 		  msgMaxSize = 1000,
+%% 		  msgFlags = snmp_misc:mk_msg_flags(PduType, 0),
+%% 		  msgSecurityModel = ?SEC_USM,
+%% 		  msgSecurityParameters = SecBytes},
+%%     Msg = #message{version = 'version-3', vsn_hdr = Hdr, data = Bytes},
+%%     case (catch snmp_pdus:enc_message_only(Msg)) of
+%% 	{'EXIT', Reason} ->
+%% 	    error("Encoding error. Pdu: ~w. Reason: ~w",[Pdu, Reason]),
+%% 	    error;
+%% 	L when list(L) ->
+%% 	    {Msg, L}
+%%     end;
+%% mk_discovery_msg(Version, Pdu, {Com, _, _, _, _}, UserName) ->
+%%     Msg = #message{version = Version, vsn_hdr = Com, data = Pdu},
+%%     case catch snmp_pdus:enc_message(Msg) of
+%% 	{'EXIT', Reason} ->
+%% 	    error("Encoding error. Pdu: ~w. Reason: ~w",[Pdu, Reason]),
+%% 	    error;
+%% 	L when list(L) -> 
+%% 	    {Msg, L}
+%%     end.
+
+
+%% mk_msg('version-3', Pdu, {Context, User, EngineID, CtxEngineId, SecLevel}, 
+%%        MsgData) ->
+%%     %% Code copied from snmp_mpd.erl
+%%     {MsgId, SecName, SecData} =
+%% 	if
+%% 	    tuple(MsgData), Pdu#pdu.type == 'get-response' ->
+%% 		MsgData;
+%% 	    true -> 
+%% 		Md = get(msg_id),
+%% 		put(msg_id, Md + 1),
+%% 		{Md, User, []}
+%% 	end,
+%%     ScopedPDU = #scopedPdu{contextEngineID = CtxEngineId,
+%% 			   contextName = Context,
+%% 			   data = Pdu},
+%%     ScopedPDUBytes = snmp_pdus:enc_scoped_pdu(ScopedPDU),
+
+%%     PduType = Pdu#pdu.type,
+%%     V3Hdr = #v3_hdr{msgID      = MsgId,
+%% 		    msgMaxSize = 1000,
+%% 		    msgFlags   = snmp_misc:mk_msg_flags(PduType, SecLevel),
+%% 		    msgSecurityModel = ?SEC_USM},
+%%     Message = #message{version = 'version-3', vsn_hdr = V3Hdr,
+%% 		       data = ScopedPDUBytes},
+%%     SecEngineID = case PduType of
+%% 		      'get-response' -> snmp_framework_mib:get_engine_id();
+%% 		      _ -> EngineID
+%% 		  end,
+%%     case catch snmp_usm:generate_outgoing_msg(Message, SecEngineID,
+%% 					      SecName, SecData, SecLevel) of
+%% 	{'EXIT', Reason} ->
+%% 	    error("Encoding error. Pdu: ~w. Reason: ~w",[Pdu, Reason]),
+%% 	    error;
+%% 	{error, Reason} ->
+%% 	    error("Encoding error. Pdu: ~w. Reason: ~w",[Pdu, Reason]),
+%% 	    error;
+%% 	Packet ->
+%% 	    Packet
+%%     end;
+%% mk_msg(Version, Pdu, {Com, _User, _EngineID, _Ctx, _SecLevel}, _SecData) ->
+%%     Msg = #message{version = Version, vsn_hdr = Com, data = Pdu},
+%%     case catch snmp_pdus:enc_message(Msg) of
+%% 	{'EXIT', Reason} ->
+%% 	    error("Encoding error. Pdu: ~w. Reason: ~w",[Pdu, Reason]),
+%% 	    error;
+%% 	B when list(B) -> 
+%% 	    B
+%%     end.
+
+
+%% handle_system_info_updated(#state{log = {Log, _OldType}} = State, 
+%% 			   audit_trail_log_type = _What) ->
+%%     %% Just to make sure, check that ATL is actually enabled
+%%     case snmpm_config:system_info(audit_trail_log) of
+%% 	{ok, true} ->
+%% 	    {ok, Type} = snmpm_config:system_info(audit_trail_log_type),
+%% 	    NewState = State#state{log = {Log, Type}},
+%% 	    {NewState, ok};
+%% 	_ ->
+%% 	    {State, {error, {adt_not_enabled}}}
+%%     end;
+%% handle_system_info_updated(_State, _What) ->
+%%     ok.
+
+handle_get_log_type(#state{log = {_Log, Value}} = State) ->
+    %% Just to make sure, check that ATL is actually enabled
+    case snmpm_config:system_info(audit_trail_log) of
+	{ok, true} ->
+	    Type = 
+		case {lists:member(read, Value), lists:member(write, Value)} of
+		    {true, true} ->
+			read_write;
+		    {true, false} ->
+			read;
+		    {false, true} ->
+			write;
+		    {false, false} ->
+			throw({State, {error, {bad_atl_type, Value}}})
+		end,
+	    {ok, Type};
+	_ ->
+	    {error, not_enabled}
+    end;
+handle_get_log_type(_State) ->
+    {error, not_enabled}.
+    
+handle_set_log_type(#state{log = {Log, OldValue}} = State, NewType) ->
+    %% Just to make sure, check that ATL is actually enabled
+    case snmpm_config:system_info(audit_trail_log) of
+	{ok, true} ->
+	    NewValue = 
+ 		case NewType of
+ 		    read ->
+ 			[read];
+ 		    write ->
+ 			[write];
+ 		    read_write ->
+ 			[read,write];
+ 		    _ ->
+ 			throw({State, {error, {bad_atl_type, NewType}}})
+ 		end,
+	    NewState = State#state{log = {Log, NewValue}},
+	    OldType = 
+		case {lists:member(read, OldValue), 
+		      lists:member(write, OldValue)} of
+		    {true, true} ->
+			read_write;
+		    {true, false} ->
+			read;
+		    {false, true} ->
+			write;
+		    {false, false} ->
+			throw({State, {error, {bad_atl_type, OldValue}}})
+		end,
+	    {NewState, {ok, OldType}};
+	_ ->
+	    {State, {error, not_enabled}}
+    end;
+handle_set_log_type(State, _NewType) ->
+    {State, {error, not_enabled}}.
+
+
+%% -------------------------------------------------------------------
+
+make_response_pdu(#pdu{request_id = ReqId, varbinds = Vbs}) ->
+    #pdu{type         = 'get-response', 
+	 request_id   = ReqId, 
+	 error_status = noError,
+	 error_index  = 0, 
+	 varbinds     = Vbs}.
+
+
+%% ----------------------------------------------------------------
+
+pdu_type_of(#pdu{type = Type}) ->
+    Type;
+pdu_type_of(TrapPdu) when is_record(TrapPdu, trappdu) ->
+    trap.
+
+
+%% -------------------------------------------------------------------
+
+%% At this point this function is used during testing
+maybe_process_extra_info(?DEFAULT_EXTRA_INFO) ->
+    ok;
+maybe_process_extra_info({?SNMPM_EXTRA_INFO_TAG, Fun}) 
+  when is_function(Fun, 0) ->
+    (catch Fun()),
+    ok;
+maybe_process_extra_info(_ExtraInfo) ->
+    ok.
+    
+
+%% -------------------------------------------------------------------
+
+t() ->
+    {A,B,C} = erlang:now(),
+    A*1000000000+B*1000+(C div 1000).
+
+
+%% -------------------------------------------------------------------
+
+logger(undefined, _Type, _Addr, _Port) ->
+    fun(_) ->
+	    ok
+    end;
+logger({{Pid, _}, Types}, Type, Addr, Port) ->
+    case lists:member(Type, Types) of
+	true ->
+	    fun(Msg) ->
+		    Pid ! {log, Msg, Addr, Port}
+	    end;
+	false ->
+	    fun(_) ->
+		    ok
+	    end
+    end.
+
+
+%% -------------------------------------------------------------------
+
+%% info_msg(F, A) ->
+%%     ?snmpm_info("NET-IF server: " ++ F, A).
+
+warning_msg(F, A) ->
+    ?snmpm_warning("NET-IF server: " ++ F, A).
+
+error_msg(F, A) ->
+    ?snmpm_error("NET-IF server: " ++ F, A).
+
+
+
+%%%-------------------------------------------------------------------
+
+% get_opt(Key, Opts) ->
+%     ?vtrace("get option ~w", [Key]),
+%     snmp_misc:get_option(Key, Opts).
+
+get_opt(Opts, Key, Def) ->
+    ?vtrace("get option ~w with default ~p", [Key, Def]),
+    snmp_misc:get_option(Key, Opts, Def).
+
+
+%% -------------------------------------------------------------------
+
+get_info(#state{sock = Id}) ->
+    ProcSize = proc_mem(self()),
+    PortInfo = get_port_info(Id),
+    [{process_memory, ProcSize}, {port_info, PortInfo}].
+
+proc_mem(P) when is_pid(P) ->
+    case (catch erlang:process_info(P, memory)) of
+	{memory, Sz} when is_integer(Sz) ->
+	    Sz;
+	_ ->
+	    undefined
+    end.
+%% proc_mem(_) ->
+%%     undefined.
+
+
+get_port_info(Id) ->
+    PortInfo = 
+	case (catch erlang:port_info(Id)) of
+	    PI when is_list(PI) ->
+		[{port_info, PI}];
+	    _ ->
+		[]
+	end,
+    PortStatus = 
+	case (catch prim_inet:getstatus(Id)) of
+	    {ok, PS} ->
+		[{port_status, PS}];
+	    _ ->
+		[]
+	end,
+    PortAct = 
+	case (catch inet:getopts(Id, [active])) of
+	    {ok, PA} ->
+		[{port_act, PA}];
+	    _ ->
+		[]
+	end,
+    PortStats = 
+	case (catch inet:getstat(Id)) of
+	    {ok, Stat} ->
+		[{port_stats, Stat}];
+	    _ ->
+		[]
+	end,
+    IfList = 
+	case (catch inet:getif(Id)) of
+	    {ok, IFs} ->
+		[{interfaces, IFs}];
+	    _ ->
+		[]
+	end,
+    BufSz = 
+	case (catch inet:getopts(Id, [recbuf, sndbuf, buffer])) of
+	    {ok, Sz} ->
+		[{buffer_size, Sz}];
+	    _ ->
+		[]
+	end,
+    [{socket, Id}] ++ 
+	IfList ++ 
+	PortStats ++ 
+	PortInfo ++ 
+	PortStatus ++ 
+	PortAct ++
+	BufSz.
+
+
+%%-----------------------------------------------------------------
+%% Counter functions
+%%-----------------------------------------------------------------
+init_counters() ->
+    F = fun(Counter) -> maybe_create_counter(Counter) end,
+    lists:map(F, counters()).
+
+reset_counters() ->
+    F = fun(Counter) -> snmpm_config:reset_stats_counter(Counter) end,
+    lists:map(F, counters()).
+
+maybe_create_counter(Counter) ->
+    snmpm_config:maybe_cre_stats_counter(Counter, 0).
+
+counters() ->
+    [
+     netIfMsgOutDrops,
+     netIfMsgInDrops,
+     netIfPduOutDrops,
+     netIfPduInDrops
+    ].
+
+inc(Name)    -> inc(Name, 1).
+inc(Name, N) -> snmpm_config:incr_stats_counter(Name, N).
+
+%% get_counters() ->
+%%     Counters = counters(),
+%%     get_counters(Counters, []).
+
+%% get_counters([], Acc) ->
+%%     lists:reverse(Acc);
+%% get_counters([Counter|Counters], Acc) ->
+%%     case snmpm_config:get_stats_counter(Counter) of
+%%         {ok, CounterVal} ->
+%%             get_counters(Counters, [{Counter, CounterVal}|Acc]);
+%%         _ ->
+%%             get_counters(Counters, Acc)
+%%     end.
+
+
+%% ----------------------------------------------------------------
+
+call(Pid, Req) ->
+    call(Pid, Req, infinity).
+
+call(Pid, Req, Timeout) ->
+    gen_server:call(Pid, Req, Timeout).
+
+cast(Pid, Msg) ->
+    gen_server:cast(Pid, Msg).
+