forked from erlang/otp
/
snmpa_mpd.erl
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/
snmpa_mpd.erl
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%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1997-2011. 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(snmpa_mpd).
-export([init/1, reset/0, inc/1, counters/0,
discarded_pdu/1,
process_packet/6, process_packet/7,
generate_response_msg/5, generate_response_msg/6,
generate_msg/5, generate_msg/6,
generate_discovery_msg/4,
process_taddrs/1,
generate_req_id/0]).
-define(SNMP_USE_V3, true).
-include("snmp_types.hrl").
-include("SNMP-MPD-MIB.hrl").
-include("SNMPv2-TM.hrl").
-include("SNMP-FRAMEWORK-MIB.hrl").
-include("TRANSPORT-ADDRESS-MIB.hrl").
-define(VMODULE,"MPD").
-include("snmp_verbosity.hrl").
-include("snmpa_internal.hrl").
-define(empty_msg_size, 24).
-record(state, {v1 = false, v2c = false, v3 = false}).
-record(note, {sec_engine_id,
sec_model,
sec_name,
sec_level,
ctx_engine_id,
ctx_name,
disco = false,
req_id}).
%%%-----------------------------------------------------------------
%%% This module implemets the Message Processing and Dispatch part of
%%% the multi-lingual SNMP agent.
%%%
%%% The MPD is responsible for:
%%% *) call the security module (auth/priv).
%%% *) decoding the message into a PDU.
%%% *) decide a suitable Access Control Model, and provide it with
%%% the data it needs.
%%% *) maintaining SNMP counters.
%%%
%%% In order to take care of the different versions of counters, it
%%% implements and maintains the union of all SNMP counters (i.e. from
%%% rfc1213 and from rfc1907). It is up to the administrator of the
%%% agent to load the correct MIB. Note that this module implements
%%% the counters only, it does not provide instrumentation functions
%%% for the counters.
%%%
%%% With the terms defined in rfc2271, this module implememts part
%%% of the Dispatcher and the Message Processing functionality.
%%%-----------------------------------------------------------------
init(Vsns) ->
?vlog("init -> entry with"
"~n Vsns: ~p", [Vsns]),
{A,B,C} = erlang:now(),
random:seed(A,B,C),
ets:insert(snmp_agent_table, {msg_id, random:uniform(2147483647)}),
ets:insert(snmp_agent_table, {req_id, random:uniform(2147483647)}),
init_counters(),
init_versions(Vsns, #state{}).
reset() ->
reset_counters(),
ok.
%%-----------------------------------------------------------------
%% Purpose: We must calculate the length of a
%% message with an empty Pdu, and zero-length community
%% string. This length is used to calculate the max
%% pdu size allowed for each request. This size is
%% dependent on two dynamic fields, the community string
%% and the pdu (varbinds actually). It is calculated
%% as EmptySize + length(CommunityString) + 4.
%% We assume that the length of the CommunityString is
%% less than 128 (thus requiring just one octet for the
%% length field (the same as the zero-length community
%% string)). 4 comes from the fact that the maximum pdu
%% size needs 31 bits which needs 5 * 7 bits to be
%% expressed. One 7bit octet is already present in the
%% empty msg, leaving 4 more 7bit octets.
%% Actually, this function is not used, we use a constant instead.
%%-----------------------------------------------------------------
%% Ret: 24
%empty_msg() ->
% M = #message{version = 'version-1', community = "", data =
% #pdu{type = 'get-response', request_id = 1,
% error_status = noError, error_index = 0, varbinds = []}},
% length(snmp_pdus:enc_message(M)) + 4.
%%-----------------------------------------------------------------
%% Func: process_packet(Packet, TDomain, TAddress, State, Log) ->
%% {ok, SnmpVsn, Pdu, PduMS, ACMData} | {discarded, Reason}
%% Types: Packet = binary()
%% TDomain = snmpUDPDomain | transportDomain()
%% TAddress = {Ip, Udp} (*but* depends on TDomain)
%% State = #state
%% Purpose: This is the main Message Dispatching function. (see
%% section 4.2.1 in rfc2272)
%%-----------------------------------------------------------------
process_packet(Packet, TDomain, TAddress, State, NoteStore, Log) ->
LocalEngineID = ?DEFAULT_LOCAL_ENGINE_ID,
process_packet(Packet, TDomain, TAddress, LocalEngineID,
State, NoteStore, Log).
process_packet(Packet, TDomain, TAddress, LocalEngineID,
State, NoteStore, Log) ->
inc(snmpInPkts),
case catch snmp_pdus:dec_message_only(binary_to_list(Packet)) of
#message{version = 'version-1', vsn_hdr = Community, data = Data}
when State#state.v1 =:= true ->
?vlog("v1, community: ~s", [Community]),
HS = ?empty_msg_size + length(Community),
v1_v2c_proc('version-1', NoteStore, Community,
TDomain, TAddress,
LocalEngineID, Data, HS, Log, Packet);
#message{version = 'version-2', vsn_hdr = Community, data = Data}
when State#state.v2c =:= true ->
?vlog("v2c, community: ~s", [Community]),
HS = ?empty_msg_size + length(Community),
v1_v2c_proc('version-2', NoteStore, Community,
TDomain, TAddress,
LocalEngineID, Data, HS, Log, Packet);
#message{version = 'version-3', vsn_hdr = V3Hdr, data = Data}
when State#state.v3 =:= true ->
?vlog("v3, msgID: ~p, msgFlags: ~p, msgSecModel: ~p",
[V3Hdr#v3_hdr.msgID,
V3Hdr#v3_hdr.msgFlags,
V3Hdr#v3_hdr.msgSecurityModel]),
v3_proc(NoteStore, Packet,
TDomain, TAddress,
LocalEngineID, V3Hdr, Data, Log);
{'EXIT', {bad_version, Vsn}} ->
?vtrace("exit: bad version: ~p",[Vsn]),
inc(snmpInBadVersions),
{discarded, snmpInBadVersions};
{'EXIT', Reason} ->
?vtrace("exit: ~p", [Reason]),
inc(snmpInASNParseErrs),
{discarded, Reason};
UnknownMessage ->
?vtrace("Unknown message: ~n ~p"
"~nwhen"
"~n State: ~p", [UnknownMessage, State]),
inc(snmpInBadVersions),
{discarded, snmpInBadVersions}
end.
discarded_pdu(false) -> ok;
discarded_pdu(Variable) -> inc(Variable).
%%-----------------------------------------------------------------
%% Handles a Community based message (v1 or v2c).
%%-----------------------------------------------------------------
v1_v2c_proc(Vsn, NoteStore, Community, Domain,
{Ip, Udp}, LocalEngineID,
Data, HS, Log, Packet) ->
TDomain = snmp_conf:mk_tdomain(Domain),
TAddress = snmp_conf:mk_taddress(Domain, Ip, Udp),
AgentMS = get_engine_max_message_size(LocalEngineID),
MgrMS = snmp_community_mib:get_target_addr_ext_mms(TDomain, TAddress),
PduMS = case MgrMS of
{ok, MMS} when MMS < AgentMS -> MMS - HS;
_ -> AgentMS - HS
end,
case (catch snmp_pdus:dec_pdu(Data)) of
Pdu when is_record(Pdu, pdu) ->
Log(Pdu#pdu.type, Packet),
inc_snmp_in_vars(Pdu),
#pdu{request_id = ReqId} = Pdu,
%% <TDomain>
%% We have added TDomain, what are the consequences?
ACMData =
{community, sec_model(Vsn), Community, TDomain, TAddress},
OkRes = {ok, Vsn, Pdu, PduMS, ACMData},
%% </TDomain>
%% Make sure that we don't process duplicate SET request
%% twice. We don't know what could happen in that case.
%% The mgr does, so he has to generate a new SET request.
?vdebug("PDU type: ~p", [Pdu#pdu.type]),
case Pdu#pdu.type of
'set-request' ->
%% Check if this message has already been processed
Key = {agent, Ip, ReqId},
case snmp_note_store:get_note(NoteStore, Key) of
undefined ->
%% Set the processed note _after_ pdu processing.
%% This makes duplicated requests be ignored even
%% if pdu processing took long time.
snmp_note_store:set_note(NoteStore,
100, Key, true),
%% Uses ACMData that snmpa_acm knows of.
OkRes;
true ->
{discarded, duplicate_pdu}
end;
_ ->
OkRes
end;
{'EXIT', Reason} ->
?vtrace("PDU decode exit: ~p",[Reason]),
inc(snmpInASNParseErrs),
{discarded, Reason};
_TrapPdu ->
{discarded, trap_pdu}
end;
v1_v2c_proc(_Vsn, _NoteStore, _Community, snmpUDPDomain, TAddress,
_LocalEngineID, _Data, _HS, _Log, _Packet) ->
{discarded, {badarg, TAddress}};
v1_v2c_proc(_Vsn, _NoteStore, _Community, TDomain, _TAddress,
_LocalEngineID, _Data, _HS, _Log, _Packet) ->
{discarded, {badarg, TDomain}}.
sec_model('version-1') -> ?SEC_V1;
sec_model('version-2') -> ?SEC_V2C.
%%-----------------------------------------------------------------
%% Handles a SNMPv3 Message, following the procedures in rfc2272,
%% section 4.2 and 7.2
%%-----------------------------------------------------------------
v3_proc(NoteStore, Packet, _TDomain, _TAddress, LocalEngineID,
V3Hdr, Data, Log) ->
case (catch v3_proc(NoteStore, Packet, LocalEngineID, V3Hdr, Data, Log)) of
{'EXIT', Reason} ->
exit(Reason);
Result ->
Result
end.
v3_proc(NoteStore, Packet, LocalEngineID, V3Hdr, Data, Log) ->
?vtrace("v3_proc -> entry with"
"~n LocalEngineID: ~p",
[LocalEngineID]),
%% 7.2.3
#v3_hdr{msgID = MsgID,
msgMaxSize = MMS,
msgFlags = MsgFlags,
msgSecurityModel = MsgSecurityModel,
msgSecurityParameters = SecParams,
hdr_size = HdrSize} = V3Hdr,
?vdebug("v3_proc -> version 3 message header [7.2.3]:"
"~n msgID = ~p"
"~n msgMaxSize = ~p"
"~n msgFlags = ~p"
"~n msgSecurityModel = ~p"
"~n msgSecurityParameters = ~w",
[MsgID, MMS, MsgFlags, MsgSecurityModel, SecParams]),
%% 7.2.4
SecModule = get_security_module(MsgSecurityModel),
%% 7.2.5
SecLevel = check_sec_level(MsgFlags),
IsReportable = snmp_misc:is_reportable(MsgFlags),
%% 7.2.6
?vtrace("v3_proc -> [7.2.4-7.2.6]"
"~n SecModule = ~p"
"~n SecLevel = ~p"
"~n IsReportable = ~p",
[SecModule, SecLevel, IsReportable]),
SecRes = (catch SecModule:process_incoming_msg(Packet, Data,
SecParams, SecLevel,
LocalEngineID)),
?vtrace("v3_proc -> message processing result: "
"~n SecRes: ~p", [SecRes]),
{SecEngineID, SecName, ScopedPDUBytes, SecData, DiscoOrPlain} =
check_sec_module_result(SecRes, V3Hdr, Data,
LocalEngineID, IsReportable, Log),
?vtrace("v3_proc -> "
"~n DiscoOrPlain: ~w"
"~n SecEngineID: ~w"
"~n SecName: ~p", [DiscoOrPlain, SecEngineID, SecName]),
%% 7.2.7
#scopedPdu{contextEngineID = ContextEngineID,
contextName = ContextName,
data = PDU} =
case (catch snmp_pdus:dec_scoped_pdu(ScopedPDUBytes)) of
ScopedPDU when is_record(ScopedPDU, scopedPdu) ->
?vtrace("v3_proc -> message processing result: "
"~n ScopedPDU: ~p", [ScopedPDU]),
ScopedPDU;
{'EXIT', Reason} ->
inc(snmpInASNParseErrs),
throw({discarded, Reason})
end,
%% We'll have to take care of the unlikely case that we receive an
%% v1 trappdu in a v3 message explicitly...
if
is_record(PDU, trappdu) ->
inc(snmpUnknownPDUHandlers),
throw({discarded, received_v1_trap});
true ->
ok
end,
?vlog("7.2.7 result: "
"~n contextEngineID: ~w"
"~n ContextName: \"~s\"", [ContextEngineID, ContextName]),
if
SecLevel =:= ?'SnmpSecurityLevel_authPriv' ->
%% encrypted message - log decrypted pdu
Log(PDU#pdu.type, {V3Hdr, ScopedPDUBytes});
true -> % otherwise, log binary
Log(PDU#pdu.type, Packet)
end,
%% Make sure a get_bulk doesn't get too big.
AgentMS = get_engine_max_message_size(LocalEngineID),
%% PduMMS is supposed to be the maximum total length of the response
%% PDU we can send. From the MMS, we need to subtract everything before
%% the PDU, i.e. Message and ScopedPDU.
%% Message: [48, TotalLen, Vsn, [Tag, LH, Hdr], [Tag, LM, MsgSec], Data]
%% 1 3 <----------- HdrSize ----------->
%% HdrSize = everything up to and including msgSecurityParameters.
%% ScopedPduData follows. This is
%% [Tag, Len, [Tag, L1, CtxName], [Tag, L2, CtxEID]]
%% i.e. 6 + length(CtxName) + length(CtxEID)
%%
%% Total: 1 + TotalLenOctets + 3 + ScopedPduDataLen
TotMMS = if AgentMS > MMS -> MMS;
true -> AgentMS
end,
TotalLenOctets = snmp_pdus:get_encoded_length(TotMMS - 1),
PduMMS = TotMMS - TotalLenOctets - 10 - HdrSize -
length(ContextName) - length(ContextEngineID),
?vdebug("v3_proc -> PDU type: ~p", [PDU#pdu.type]),
case PDU#pdu.type of
report when DiscoOrPlain =:= discovery ->
%% Discovery stage 1 response
Key = {agent, MsgID},
Note = snmp_note_store:get_note(NoteStore, Key),
case Note of
#note{sec_engine_id = "",
sec_model = _MsgSecModel,
sec_name = "",
sec_level = _SecLevel,
ctx_engine_id = _CtxEngineID,
ctx_name = _CtxName,
disco = true,
req_id = _ReqId} ->
%% This is part of the discovery process initiated by us.
%% Response to the discovery stage 1 request
?vdebug("v3_proc -> discovery stage 1 response", []),
{ok, 'version-3', PDU, PduMMS, {discovery, SecEngineID}};
#note{sec_engine_id = SecEngineID,
sec_model = _MsgSecModel,
sec_name = SecName,
sec_level = SecLevel,
ctx_engine_id = _CtxEngineID,
ctx_name = _CtxName,
disco = true,
req_id = _ReqId} ->
%% This is part of the discovery process initiated by us.
%% Response to the discovery stage 2 request
?vdebug("v3_proc -> discovery stage 2 response", []),
{ok, 'version-3', PDU, PduMMS, discovery};
_ ->
%% 7.2.11
DiscardReason = {bad_disco_note, Key, Note},
throw({discarded, DiscardReason})
end;
report ->
%% 7.2.11
throw({discarded, report});
'get-response' -> %% As a result of a sent inform-request?
%% 7.2.12
Key = {agent, MsgID},
Note = snmp_note_store:get_note(NoteStore, Key),
case Note of
#note{sec_engine_id = "",
sec_model = _MsgSecModel,
sec_name = "",
sec_level = _SecLevel,
ctx_engine_id = _CtxEngineID,
ctx_name = _CtxName,
disco = true,
req_id = _ReqId} ->
%% This is part of the discovery process initiated by us.
%% Response to the discovery stage 1 request
?vdebug("v3_proc -> discovery stage 1 response", []),
{ok, 'version-3', PDU, PduMMS, {discovery, SecEngineID}};
#note{sec_engine_id = SecEngineID,
sec_model = _MsgSecModel,
sec_name = SecName,
sec_level = SecLevel,
ctx_engine_id = _CtxEngineID,
ctx_name = _CtxName,
disco = true,
req_id = _ReqId} ->
%% This is part of the discovery process initiated by us.
%% Response to the discovery stage 2 request
?vdebug("v3_proc -> discovery stage 2 response", []),
{ok, 'version-3', PDU, PduMMS, discovery};
#note{sec_engine_id = SecEngineID,
sec_model = MsgSecurityModel,
sec_name = SecName,
sec_level = SecLevel,
ctx_engine_id = ContextEngineID,
ctx_name = ContextName,
disco = false,
req_id = _ReqId} ->
{ok, 'version-3', PDU, PduMMS, undefined};
_ ->
inc(snmpUnknownPDUHandlers),
throw({discarded, {no_outstanding_req, MsgID}})
end;
'snmpv2-trap' ->
inc(snmpUnknownPDUHandlers),
throw({discarded, received_v2_trap});
Type ->
%% 7.2.13
SnmpEngineID = LocalEngineID,
?vtrace("v3_proc -> 7.2.13", []),
case SecEngineID of
SnmpEngineID when (DiscoOrPlain =:= discovery) ->
%% This is a discovery step 2 message!
?vtrace("v3_proc -> discovery stage 2", []),
generate_discovery2_report_msg(MsgID,
MsgSecurityModel,
SecName,
SecLevel,
ContextEngineID,
ContextName,
SecData,
PDU,
LocalEngineID,
Log);
SnmpEngineID when (DiscoOrPlain =:= plain) ->
%% 4.2.2.1.1 - we don't handle proxys yet => we only
%% handle ContextEngineID to ourselves
case ContextEngineID of
SnmpEngineID ->
%% Uses ACMData that snmpa_acm knows of.
{ok, 'version-3', PDU, PduMMS,
{v3, MsgID, MsgSecurityModel, SecName, SecLevel,
ContextEngineID, ContextName, SecData}};
_ ->
%% 4.2.2.1.2
NIsReportable = snmp_misc:is_reportable_pdu(Type),
Val = inc(snmpUnknownPDUHandlers),
ErrorInfo =
{#varbind{oid = ?snmpUnknownPDUHandlers,
variabletype = 'Counter32',
value = Val},
SecName,
[{securityLevel, SecLevel},
{contextEngineID, ContextEngineID},
{contextName, ContextName}]},
case generate_v3_report_msg(MsgID,
MsgSecurityModel,
Data, LocalEngineID,
ErrorInfo, Log) of
{ok, Report} when NIsReportable =:= true ->
{discarded, snmpUnknownPDUHandlers, Report};
_ ->
{discarded, snmpUnknownPDUHandlers}
end
end;
"" ->
%% This is a discovery step 1 message!!
?vtrace("v3_proc -> discovery step 1", []),
generate_discovery1_report_msg(MsgID,
MsgSecurityModel,
SecName,
SecLevel,
ContextEngineID,
ContextName,
SecData,
PDU,
LocalEngineID,
Log);
_ ->
{discarded, {badSecurityEngineID, SecEngineID}}
end
end.
get_security_module(?SEC_USM) ->
snmpa_usm;
get_security_module(_) ->
inc(snmpUnknownSecurityModels),
throw({discarded, snmpUnknownSecurityModels}).
check_sec_level([MsgFlag]) ->
SecLevel = MsgFlag band 3,
if
SecLevel == 2 ->
inc(snmpInvalidMsgs),
throw({discarded, snmpInvalidMsgs});
true ->
SecLevel
end;
check_sec_level(Unknown) ->
?vlog("invalid msgFlags: ~p",[Unknown]),
inc(snmpInvalidMsgs),
throw({discarded, snmpInvalidMsgs}).
check_sec_module_result(Res, V3Hdr, Data, LocalEngineID, IsReportable, Log) ->
case Res of
{ok, X} ->
X;
{error, Reason, []} -> % case 7.2.6 b
?vdebug("security module result [7.2.6-b]:"
"~n Reason: ~p", [Reason]),
throw({discarded, {securityError, Reason}});
{error, Reason, ErrorInfo} when IsReportable =:= true -> % case 7.2.6 a
?vdebug("security module result when reportable [7.2.6-a]:"
"~n Reason: ~p"
"~n ErrorInfo: ~p", [Reason, ErrorInfo]),
#v3_hdr{msgID = MsgID, msgSecurityModel = MsgSecModel} = V3Hdr,
Pdu = get_scoped_pdu(Data),
case generate_v3_report_msg(MsgID, MsgSecModel, Pdu,
LocalEngineID, ErrorInfo, Log) of
{ok, Report} ->
throw({discarded, {securityError, Reason}, Report});
{discarded, _SomeOtherReason} ->
throw({discarded, {securityError, Reason}})
end;
{error, Reason, ErrorInfo} ->
?vdebug("security module result when not reportable:"
"~n Reason: ~p"
"~n ErrorInfo: ~p", [Reason, ErrorInfo]),
throw({discarded, {securityError, Reason}});
Else ->
?vdebug("security module result:"
"~n Else: ~p", [Else]),
throw({discarded, {securityError, Else}})
end.
get_scoped_pdu(D) when is_list(D) ->
(catch snmp_pdus:dec_scoped_pdu(D));
get_scoped_pdu(D) ->
D.
%%-----------------------------------------------------------------
%% Executed when a response or report message is generated.
%%-----------------------------------------------------------------
generate_response_msg(Vsn, RePdu, Type, ACMData, Log) ->
generate_response_msg(Vsn, RePdu, Type, ACMData, Log, 1).
generate_response_msg(Vsn, RePdu, Type, ACMData, Log, N) when is_integer(N) ->
LocalEngineID = ?DEFAULT_LOCAL_ENGINE_ID,
generate_response_msg(Vsn, RePdu, Type, ACMData, LocalEngineID, Log, N);
generate_response_msg(Vsn, RePdu, Type, ACMData, LocalEngineID, Log) ->
generate_response_msg(Vsn, RePdu, Type, ACMData, LocalEngineID, Log, 1).
generate_response_msg(Vsn, RePdu, Type,
{community, _SecModel, Community, _TDomain, _TAddress},
LocalEngineID,
Log, _) ->
case catch snmp_pdus:enc_pdu(RePdu) of
{'EXIT', Reason} ->
user_err("failed encoding pdu: "
"(pdu: ~w, community: ~w): ~n~w",
[RePdu, Community, Reason]),
{discarded, Reason};
PduBytes ->
Message = #message{version = Vsn,
vsn_hdr = Community,
data = PduBytes},
case catch list_to_binary(
snmp_pdus:enc_message_only(Message)) of
{'EXIT', Reason} ->
user_err("failed encoding message only "
"(pdu: ~w, community: ~w): ~n~w",
[RePdu, Community, Reason]),
{discarded, Reason};
Packet ->
MMS = get_engine_max_message_size(LocalEngineID),
case size(Packet) of
Len when Len =< MMS ->
Log(Type, Packet),
inc_snmp_cnt_vars(Type, RePdu),
inc_snmp_out_vars(RePdu),
{ok, Packet};
Len ->
?vlog("pdu to big:"
"~n Max message size: ~p"
"~n Encoded message size: ~p",
[MMS,Len]),
too_big(Vsn, RePdu, Community, Log, MMS, Len)
end
end
end;
generate_response_msg(Vsn, RePdu, Type,
{v3, MsgID, MsgSecurityModel, SecName, SecLevel,
ContextEngineID, ContextName, SecData},
LocalEngineID,
Log, N) ->
%% rfc2272: 7.1 steps 6-8
ScopedPDU = #scopedPdu{contextEngineID = ContextEngineID,
contextName = ContextName,
data = RePdu},
case catch snmp_pdus:enc_scoped_pdu(ScopedPDU) of
{'EXIT', Reason} ->
user_err("failed encoded scoped pdu "
"(pdu: ~w, contextName: ~w): ~n~w",
[RePdu, ContextName, Reason]),
{discarded, Reason};
ScopedPDUBytes ->
AgentMS = get_engine_max_message_size(LocalEngineID),
V3Hdr = #v3_hdr{msgID = MsgID,
msgMaxSize = AgentMS,
msgFlags = snmp_misc:mk_msg_flags(Type, SecLevel),
msgSecurityModel = MsgSecurityModel},
Message = #message{version = Vsn,
vsn_hdr = V3Hdr,
data = ScopedPDUBytes},
%% We know that the security model is valid when we
%% generate a response.
SecModule =
case MsgSecurityModel of
?SEC_USM ->
snmpa_usm
end,
SecEngineID = LocalEngineID,
?vtrace("generate_response_msg -> SecEngineID: ~w", [SecEngineID]),
case (catch SecModule:generate_outgoing_msg(Message,
SecEngineID,
SecName,
SecData,
SecLevel,
LocalEngineID)) of
{'EXIT', Reason} ->
config_err("~p (message: ~p)", [Reason, Message]),
{discarded, Reason};
{error, Reason} ->
config_err("~p (message: ~p)", [Reason, Message]),
{discarded, Reason};
OutMsg when is_list(OutMsg) ->
%% Check the packet size. Send the msg even
%% if it's larger than the mgr can handle - it
%% will be dropped. Just check against the
%% internal size. For GET-BULk responses: we
%% *know* that we're within the right limits,
%% because of the calculation we do when we
%% receive the bulk-request.
Packet = list_to_binary(OutMsg),
case size(Packet) of
Len when Len =< AgentMS ->
if
SecLevel =:= 3 ->
%% encrypted - log decrypted pdu
Log(Type, {V3Hdr, ScopedPDUBytes});
true ->
%% otherwise log the entire msg
Log(Type, Packet)
end,
inc_snmp_cnt_vars(Type, RePdu),
inc_snmp_out_vars(RePdu),
{ok, Packet};
Len when N =:= 2 ->
?vlog("packet max size exceeded: "
"~n Max: ~p"
"~n Len: ~p",
[AgentMS,Len]),
inc(snmpSilentDrops),
{discarded, tooBig};
Len ->
?vlog("packet max size exceeded: "
"~n N: ~p"
"~n Max: ~p"
"~n Len: ~p",
[N, AgentMS, Len]),
TooBigPdu = RePdu#pdu{error_status = tooBig,
error_index = 0,
varbinds = []},
generate_response_msg(Vsn, TooBigPdu, Type,
{v3, MsgID,
MsgSecurityModel,
SecName, SecLevel,
ContextEngineID,
ContextName,
SecData},
LocalEngineID, Log, N+1)
end
end
end.
generate_v3_report_msg(MsgID, MsgSecurityModel, Data, LocalEngineID,
ErrorInfo, Log) ->
{Varbind, SecName, Opts} = ErrorInfo,
ReqId =
if
is_record(Data, scopedPdu) ->
(Data#scopedPdu.data)#pdu.request_id;
true ->
0 %% RFC2572, 7.1.3.c.4
end,
?vtrace("Report ReqId: ~p",[ReqId]),
Pdu = #pdu{type = report,
request_id = ReqId,
error_status = noError,
error_index = 0,
varbinds = [Varbind]},
SecLevel = snmp_misc:get_option(securityLevel, Opts, 0),
SnmpEngineID = LocalEngineID,
ContextEngineID =
snmp_misc:get_option(contextEngineID, Opts, SnmpEngineID),
ContextName = snmp_misc:get_option(contextName, Opts, ""),
SecData = snmp_misc:get_option(sec_data, Opts, []),
generate_response_msg('version-3', Pdu, report,
{v3, MsgID, MsgSecurityModel, SecName, SecLevel,
ContextEngineID, ContextName, SecData},
LocalEngineID, Log).
%% req_id(#scopedPdu{data = #pdu{request_id = ReqId}}) ->
%% ?vtrace("Report ReqId: ~p",[ReqId]),
%% ReqId;
%% req_id(_) ->
%% 0. % RFC2572, 7.1.3.c.4
%% maybe_generate_discovery1_report_msg() ->
%% case (catch DiscoveryHandler:handle_discovery1(Ip, Udp, EngineId)) of
%% {ok, Entry} when is_record(Entry, snmp_discovery_data1) ->
%% ok;
%% ignore ->
%% ok;
%% {error, Reason} ->
%% Response to stage 1 discovery message (terminating, i.e. from the manager)
generate_discovery1_report_msg(MsgID, MsgSecurityModel,
SecName, SecLevel,
ContextEngineID, ContextName,
{SecData, Oid, Value},
#pdu{request_id = ReqId},
LocalEngineID, Log) ->
?vtrace("generate_discovery1_report_msg -> entry with"
"~n ReqId: ~p"
"~n Value: ~p", [ReqId, Value]),
Varbind = #varbind{oid = Oid,
variabletype = 'Counter32',
value = Value,
org_index = 1},
PduOut = #pdu{type = report,
request_id = ReqId,
error_status = noError,
error_index = 0,
varbinds = [Varbind]},
case generate_response_msg('version-3', PduOut, report,
{v3, MsgID, MsgSecurityModel, SecName, SecLevel,
ContextEngineID, ContextName, SecData},
LocalEngineID, Log) of
{ok, Packet} ->
{discovery, Packet};
Error ->
Error
end.
%% Response to stage 2 discovery message (terminating, i.e. from the manager)
generate_discovery2_report_msg(MsgID, MsgSecurityModel,
SecName, SecLevel,
ContextEngineID, ContextName,
SecData, #pdu{request_id = ReqId},
LocalEngineID, Log) ->
?vtrace("generate_discovery2_report_msg -> entry with"
"~n ReqId: ~p", [ReqId]),
SecModule = get_security_module(MsgSecurityModel),
Vb = SecModule:current_statsNotInTimeWindows_vb(),
PduOut = #pdu{type = report,
request_id = ReqId,
error_status = noError,
error_index = 0,
varbinds = [Vb]},
case generate_response_msg('version-3', PduOut, report,
{v3, MsgID, MsgSecurityModel, SecName, SecLevel,
ContextEngineID, ContextName, SecData},
LocalEngineID, Log) of
{ok, Packet} ->
{discovery, Packet};
Error ->
Error
end.
too_big(Vsn, Pdu, Community, Log, _MMS, _Len)
when Pdu#pdu.type =:= 'get-response' ->
ErrPdu =
if
Vsn =:= 'version-1' ->
%% In v1, the varbinds should be identical to the incoming
%% request. It isn't identical now!
%% Make acceptable (?) approximation.
V = set_vb_null(Pdu#pdu.varbinds),
Pdu#pdu{error_status = tooBig, error_index = 0, varbinds = V};
true ->
%% In v2, varbinds should be empty (reasonable!)
Pdu#pdu{error_status = tooBig, error_index = 0, varbinds = []}
end,
case catch snmp_pdus:enc_pdu(ErrPdu) of
{'EXIT', Reason} ->
user_err("failed encoding pdu (pdu: ~w, community: ~w): ~n~w",
[ErrPdu, Community, Reason]),
{discarded, Reason};
PduBytes ->
Message = #message{version = Vsn, vsn_hdr = Community,
data = PduBytes},
case catch snmp_pdus:enc_message_only(Message) of
{'EXIT', Reason} ->
user_err("failed encoding message only"
"(pdu: ~w, community: ~w): ~n~w",
[ErrPdu, Community, Reason]),
{discarded, Reason};
Packet ->
Bin = list_to_binary(Packet),
Log(Pdu#pdu.type, Bin),
inc_snmp_out_vars(ErrPdu),
{ok, Bin}
end
end;
too_big(_Vsn, Pdu, _Community, _Log, MMS, Len) ->
user_err("encoded pdu, ~p bytes, exceeded "
"max message size of ~p bytes. Pdu: ~n~w",
[Len, MMS, Pdu]),
{discarded, tooBig}.
set_vb_null([Vb | Vbs]) ->
[Vb#varbind{variabletype = 'NULL', value = 'NULL'} | set_vb_null(Vbs)];
set_vb_null([]) ->
[].
%%-----------------------------------------------------------------
%% Executed when a message that isn't a response is generated, i.e.
%% a trap or an inform.
%%-----------------------------------------------------------------
generate_msg(Vsn, NoteStore, Pdu, ACMData, To) ->
LocalEngineID = ?DEFAULT_LOCAL_ENGINE_ID,
generate_msg(Vsn, NoteStore, Pdu, ACMData, LocalEngineID, To).
generate_msg(Vsn, _NoteStore, Pdu, {community, Community}, LocalEngineID, To) ->
Message = #message{version = Vsn, vsn_hdr = Community, data = Pdu},
case catch list_to_binary(snmp_pdus:enc_message(Message)) of
{'EXIT', Reason} ->
user_err("failed encoding message "
"(pdu: ~w, community: ~w): ~n~w",
[Pdu, Community, Reason]),
{discarded, Reason};
Packet ->
AgentMax = get_engine_max_message_size(LocalEngineID),
case size(Packet) of
Len when Len =< AgentMax ->
{ok, mk_v1_v2_packet_list(To, Packet, Len, Pdu)};
Len ->
?vlog("packet max size exceeded: "
"~n Max: ~p"
"~n Len: ~p",
[AgentMax, Len]),
{discarded, tooBig}
end
end;
generate_msg('version-3', NoteStore, Pdu,
{v3, ContextEngineID, ContextName}, LocalEngineID, To) ->
%% rfc2272: 7.1 step 6
ScopedPDU = #scopedPdu{contextEngineID = LocalEngineID,
contextName = ContextName,
data = Pdu},
case (catch snmp_pdus:enc_scoped_pdu(ScopedPDU)) of
{'EXIT', Reason} ->
user_err("failed encoding scoped pdu "
"(pdu: ~w, contextName: ~w): ~n~w",
[Pdu, ContextName, Reason]),
{discarded, Reason};
ScopedPDUBytes ->
{ok, mk_v3_packet_list(NoteStore, To, ScopedPDUBytes, Pdu,
ContextEngineID, ContextName,
LocalEngineID)}
end.
generate_discovery_msg(NoteStore, Pdu, MsgData, To) ->
Timeout = 1500,
generate_discovery_msg(NoteStore, Pdu, MsgData, Timeout, To).
generate_discovery_msg(NoteStore, Pdu, MsgData, Timeout, To) ->
{SecData, ContextEngineID, ContextName} = MsgData,
{SecModel, SecName, SecLevelFlag, TargetName} = SecData,
{ManagerEngineId, InitialUserName} =
case get_target_engine_id(TargetName) of
{ok, discovery} ->
{"", ""}; % Discovery stage 1
{ok, {discovery, IUN}} ->
{"", IUN}; % Discovery stage 1
{ok, TargetEngineId} ->
{TargetEngineId, ""} % Discovery stage 2
end,
generate_discovery_msg(NoteStore, Pdu,
ContextEngineID, ContextName,
SecModel, SecName, SecLevelFlag,
ManagerEngineId,
InitialUserName,
Timeout, To).
generate_discovery_msg(NoteStore, Pdu,
ContextEngineID, ContextName,
SecModel, _SecName, _SecLevelFlag,
"" = ManagerEngineID,
InitialUserName,
Timeout, To) ->
%% Discovery step 1 uses SecLevel = noAuthNoPriv
SecName = "",
SecLevelFlag = 0, % ?'SnmpSecurityLevel_noAuthNoPriv',
generate_discovery_msg2(NoteStore, Pdu,
ContextEngineID, ManagerEngineID,
SecModel, SecName, SecLevelFlag,
InitialUserName,
ContextName, Timeout, To);
generate_discovery_msg(NoteStore, Pdu,
ContextEngineID, ContextName,
SecModel, SecName, SecLevelFlag,
ManagerEngineID,
InitialUserName,
Timeout, To) ->
%% SecLevelFlag = 1, % ?'SnmpSecurityLevel_authNoPriv',
generate_discovery_msg2(NoteStore, Pdu,
ContextEngineID, ManagerEngineID,
SecModel, SecName, SecLevelFlag,
InitialUserName,
ContextName, Timeout, To).
generate_discovery_msg2(NoteStore, Pdu,
ContextEngineID, ManagerEngineID,
SecModel, SecName, SecLevelFlag,
InitialUserName,
ContextName, Timeout, To) ->
%% rfc2272: 7.1.6
ScopedPDU = #scopedPdu{contextEngineID = ContextEngineID,
contextName = ContextName,
data = Pdu},
case (catch snmp_pdus:enc_scoped_pdu(ScopedPDU)) of
{'EXIT', Reason} ->
user_err("failed encoding scoped pdu "
"(pdu: ~w, contextName: ~w): ~n~w",
[Pdu, ContextName, Reason]),
{discarded, Reason};
ScopedPDUBytes ->
{ok, generate_discovery_msg(NoteStore, To,
Pdu, ScopedPDUBytes,
ContextEngineID, ManagerEngineID,
SecModel, SecName, SecLevelFlag,
InitialUserName,
ContextName, Timeout)}
end.
%% Timeout is in msec but note timeout is in 1/10 seconds
discovery_note_timeout(Timeout) ->
(Timeout div 100) + 1.
generate_discovery_msg(NoteStore, {TDomain, TAddress},
Pdu, ScopedPduBytes,
ContextEngineID, ManagerEngineID,
SecModel, SecName, SecLevelFlag,
InitialUserName,
ContextName, Timeout) ->
{ok, {_Domain, Address}} = transform_taddr(TDomain, TAddress),
%% 7.1.7
?vdebug("generate_discovery_msg -> 7.1.7 (~w)", [ManagerEngineID]),
MsgID = generate_msg_id(),
PduType = Pdu#pdu.type,
MsgFlags = mk_msg_flags(PduType, SecLevelFlag),
V3Hdr = #v3_hdr{msgID = MsgID,
msgMaxSize = get_max_message_size(),