[SNMP4J] Behaviour of ResponseListener in SNMP V3
Frank Fock
fock at agentpp.com
Thu Oct 6 21:45:51 CEST 2016
Hi Peter,
The PDU that is send is a SNMPv2c GET request and not a v3 request.
So this cannot be an issue with the USM or other v3 processing.
To be able to reproduce the issue I might need more details. If it is indeed
a v3 request, I would like to have the log for it. In addition,
is the "unknown user" locally unknown the the USM of the command
sender or remotely unknown to the command responder.
If locally unknown, a exception is thrown during the send call.
Best regards,
Frank
Am 06.10.2016 um 09:45 schrieb Peter Verthez:
> Hi Frank,
>
> The PDU instance is not used in another thread, only in this one. All
> normal functionality works properly (we started to use async requests
> 1.5 years ago), except for this timeout due to a wrong security name
> being used. I'm not sure whether that is a new regression or
> something that wasn't tested before by our test team.
>
> I'm not sure which further information I have to give, I can't provide
> the full source code as this is a proprietary product. If you want me
> to debug something specific I can do that.
>
> Best regards,
> Peter.
>
>
> On 5/10/2016 22:55, Frank Fock wrote:
>> Hi Peter,
>>
>> From the provided send call alone, I cannot verify if the parameters
>> are correctly
>> setup. The SnmpUserTarget.this, for example, might not work if called
>> in a constructor
>> of that class.
>>
>> The pdu instance might be used concurrently by another thread (with
>> same or different
>> request ID), which would corrupt the pending request management.
>>
>> Best regards,
>> Frank
>>
>> Am 05.10.2016 um 08:14 schrieb Peter Verthez:
>>> Hi Frank,
>>>
>>> The call of the send method was in the last line of my code snippet:
>>> session is an Snmp object.
>>>
>>> Best regards,
>>> Peter.
>>>
>>>
>>> On 4/10/2016 20:12, Frank Fock wrote:
>>>>
>>>> Hi Peter,
>>>>
>>>> How do call the send method? Is the listener set there?
>>>> All fields null should not happen normally....
>>>>
>>>> Best regards,
>>>> Frank
>>>>
>>>> Am 04.10.2016 um 11:18 schrieb Peter Verthez:
>>>>> Hi Frank,
>>>>>
>>>>> Our code is simply:
>>>>>
>>>>> ResponseListener respListener = new
>>>>> ResponseListener() {
>>>>> @Override
>>>>> public void onResponse(ResponseEvent event) {
>>>>> // canceling is required as per SNMP4J
>>>>> documentation
>>>>> ((Snmp)event.getSource()).cancel(event.getRequest(), this);
>>>>> PDU response = event.getResponse();
>>>>> updateStats(session, agentId,
>>>>> startTime, response);
>>>>> listener.onResponse(response,
>>>>> event.getUserObject());
>>>>> }
>>>>> };
>>>>>
>>>>> session.send(pdu, SnmpUserTarget.this,
>>>>> userContext, respListener);
>>>>>
>>>>> It doesn't reach even the first line of the onResponse method.
>>>>>
>>>>> I've been debugging a little, and the PendingRequest.run() method
>>>>> in the Snmp class is always being exited because all fields are
>>>>> null, and so it never calls the onResponse method on the
>>>>> listener. This is also what the debug message says:
>>>>>
>>>>> 2016-09-28 16:43:36,861 DEBUG [SNMP4J Timer]-[org.snmp4j.Snmp]
>>>>> PendingRequest canceled key=null, pdu=null, target=null,
>>>>> transport=null, listener=null
>>>>>
>>>>> I've then put a breakpoint in the cancel() method, and it gets run
>>>>> when the following report is coming in (copied from the debugger):
>>>>>
>>>>> REPORT[{contextEngineID=80:00:02:7d:03:00:90:d0:6d:fa:bc,
>>>>> contextName=nt}, requestID=0, errorStatus=0, errorIndex=0,
>>>>> VBS[1.3.6.1.6.3.15.1.1.3.0 = 18]]
>>>>>
>>>>> Best regards,
>>>>> Peter.
>>>>>
>>>>>
>>>>> On 3/10/2016 23:06, Frank Fock wrote:
>>>>>> Hi Peter,
>>>>>>
>>>>>> Yes, the ResponseEvent should be returned after the timeout with
>>>>>> a null response.
>>>>>> From the log, it is unclear why you do not get the event. Is
>>>>>> there an if-statement
>>>>>> that ignores the ResponseEvent with null response in your code?
>>>>>>
>>>>>> Best regards,
>>>>>> Frank
>>>>>>
>>>>>> Am 30.09.2016 um 10:12 schrieb Peter Verthez:
>>>>>>> Hi Frank,
>>>>>>>
>>>>>>> If we are using asynchronous SNMP calls with SNMPv3, what should
>>>>>>> be the behaviour in case of timeout, when you used wrong
>>>>>>> credentials such as a wrong user name. Should the
>>>>>>> ResponseListener always be triggered, with event.getResponse() =
>>>>>>> null, after the timeout?
>>>>>>>
>>>>>>> I would expect that, but it looks like this is not what I'm
>>>>>>> seeing: the ResponseListener does not seem to be triggered in
>>>>>>> that case. So this means that our application never knows that a
>>>>>>> timeout occurred. We are using currently SNMP4J 2.5.0. Debug
>>>>>>> logging from SNMP4J:
>>>>>>>
>>>>>>> 2016-09-28 16:43:31,768 DEBUG
>>>>>>> [JM-49-Ping-Ping-4]-[org.snmp4j.Snmp] Running pending async
>>>>>>> request with handle PduHandle[1071987217] and retry count left 1
>>>>>>> 2016-09-28 16:43:31,768 DEBUG
>>>>>>> [JM-49-Ping-Ping-4]-[org.snmp4j.transport.DefaultUdpTransportMapping]
>>>>>>> Sending message to 135.249.41.44/161 with length 268:
>>>>>>> 30:82:01:08:02:01:01:04:06:70:75:62:6c:69:63:a0:81:fa:02:04:3f:e5:3a:11:02:01:00:02:01:00:30:81:eb:30:10:06:0c:2b:06:01:04:01:84:7d:3d:01:09:03:00:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:17:01:06:00:05:00:30:10:06:0c:2b:06:01:04:01:84:7d:3d:01:0b:09:00:05:00:30:10:06:0c:2b:06:01:04:01:84:7d:3d:01:0b:02:00:05:00:30:12:06:0e:2b:06:01:04:01:84:7d:3d:01:23:3c:03:02:00:05:00:30:0c:06:08:2b:06:01:02:01:01:03:00:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:17:01:07:00:05:00:30:0c:06:08:2b:06:01:02:01:01:02:00:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:17:01:03:00:05:00:30:10:06:0c:2b:06:01:04:01:84:7d:3d:01:09:0d:00:05:00:30:12:06:0e:2b:06:01:04:01:84:7d:3d:01:17:02:01:04:01:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:09:1c:01:00:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:09:1c:02:00:05:00
>>>>>>>
>>>>>>> 2016-09-28 16:43:35,771 DEBUG [SNMP4J Timer]-[org.snmp4j.Snmp]
>>>>>>> Running pending async request with handle PduHandle[1071987217]
>>>>>>> and retry count left 0
>>>>>>> 2016-09-28 16:43:35,771 DEBUG [SNMP4J
>>>>>>> Timer]-[org.snmp4j.transport.DefaultUdpTransportMapping] Sending
>>>>>>> message to 135.249.41.44/161 with length 268:
>>>>>>> 30:82:01:08:02:01:01:04:06:70:75:62:6c:69:63:a0:81:fa:02:04:3f:e5:3a:11:02:01:00:02:01:00:30:81:eb:30:10:06:0c:2b:06:01:04:01:84:7d:3d:01:09:03:00:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:17:01:06:00:05:00:30:10:06:0c:2b:06:01:04:01:84:7d:3d:01:0b:09:00:05:00:30:10:06:0c:2b:06:01:04:01:84:7d:3d:01:0b:02:00:05:00:30:12:06:0e:2b:06:01:04:01:84:7d:3d:01:23:3c:03:02:00:05:00:30:0c:06:08:2b:06:01:02:01:01:03:00:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:17:01:07:00:05:00:30:0c:06:08:2b:06:01:02:01:01:02:00:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:17:01:03:00:05:00:30:10:06:0c:2b:06:01:04:01:84:7d:3d:01:09:0d:00:05:00:30:12:06:0e:2b:06:01:04:01:84:7d:3d:01:17:02:01:04:01:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:09:1c:01:00:05:00:30:11:06:0d:2b:06:01:04:01:84:7d:3d:01:09:1c:02:00:05:00
>>>>>>>
>>>>>>> 2016-09-28 16:43:36,861 DEBUG [SNMP4J Timer]-[org.snmp4j.Snmp]
>>>>>>> PendingRequest canceled key=null, pdu=null, target=null,
>>>>>>> transport=null, listener=null
>>>>>>> 2016-09-28 16:43:43,771 DEBUG [SNMP4J Timer]-[org.snmp4j.Snmp]
>>>>>>> Request timed out: 1071987217
>>>>>>> 2016-09-28 16:43:43,772 DEBUG [SNMP4J Timer]-[org.snmp4j.Snmp]
>>>>>>> Cancelling pending request with handle PduHandle[1071987217]
>>>>>>>
>>>>>>> Best regards,
>>>>>>> Peter.
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
>
--
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