Hi Shenaz,
The AdventNet browser does not handle this correctly.
It should not process an incorrectly encoded SNMP
packet although it may be valid BER (where length > 32bit
are allowed).
If the client cannot be convinced that the agent bug
needs to be fixed you could implement a workaround
by changing the BER decoding of SNMP4J. However, if you
do that, you can run into DoS issues when SNMP4J tries
to process such long lengths.
Regards,
Frank
[email protected] wrote:
Hi Frank,
Thanks a ton for such a quick reply. So you mean its game over? :(
Do you have any suggestions how I should handle this situation? The
client does not want me to show SnmpTimeOut. Because when he checks from
the Adventnet MibBrowser, he can see the value. Although it is an SNMP
agent issue, I have been asked to handle it my application.
Regards
Shenaz
-----Original Message-----
From: Frank Fock [mailto:[email protected]]
Sent: Friday, December 19, 2008 9:59 PM
To: Shenaz Mohamed assu (WT01 - Telecom Equipment)
Cc: [email protected]
Subject: Re: [SNMP4J] IOException in DefaultUDPTransportMapping
Hi Shenaz,
You cannot report that error back, because when you cannot decode the
response (because of an BER encoding error), you cannot match the
response with the request. Game over ;-)
Regards,
Frank
[email protected] wrote:
Hi All,
I'm facing an issue with SNMP GET. While sending the PDU to the SNMP
agent with public ResponseEvent send(PDU pdu, Target target,
TransportMapping transport) throws IOException method, i'm getting the
following exception.
java.io.IOException: Length greater than 32bit are not supported for
integers: at position 49 at
org.snmp4j.asn1.BER.decodeInteger(BER.java:627)
at org.snmp4j.smi.Integer32.decodeBER(Integer32.java:62)
at org.snmp4j.smi.Variable.createFromBER(Variable.java:170)
at org.snmp4j.smi.VariableBinding.decodeBER(VariableBinding.java:164)
at org.snmp4j.PDUv1.decodeBER(PDUv1.java:169)
at org.snmp4j.mp.MPv1.prepareDataElements(MPv1.java:170)
at
org.snmp4j.MessageDispatcherImpl.dispatchMessage(MessageDispatcherImpl
.java:241) at
org.snmp4j.MessageDispatcherImpl.processMessage(MessageDispatcherImpl.
java:313) at
org.snmp4j.MessageDispatcherImpl.processMessage(MessageDispatcherImpl.
java:276) at
org.snmp4j.transport.AbstractTransportMapping.fireProcessMessage(Abstr
actTransportMapping.java:81) at
org.snmp4j.transport.DefaultUdpTransportMapping$ListenThread.run(Defau
ltUdpTransportMapping.java:282)
From this what I've understood is that, the SNMP agent is returning a
value larger than integer for the attribute that is expected to return
an integer value. This IOException is caught and logged in
DefaultUdpTransportMapping. So in my application I'll get ResponseEvent
with a null PDU and i'll throw an SnmpTimeOutError as the response is
null.
The problem is that I do not want to show the error as an SnmpTimeOut.
I want to show the exact reason in my application. So I tried
modifying the code and I threw a RunTimeException from the
MessageDispatcherImpl after catching the IOException. Then I got the
below log
Exception in thread "DefaultUDPTransportMapping_192.168.234.72/0"
java.lang.RuntimeException: Length greater than 32bit are not
supported for integers: at position 49 at
org.snmp4j.MessageDispatcherImpl.processMessage(MessageDispatcherImpl.
java:324) at
org.snmp4j.MessageDispatcherImpl.processMessage(MessageDispatcherImpl.
java:276) at
org.snmp4j.transport.AbstractTransportMapping.fireProcessMessage(Abstr
actTransportMapping.java:81) at
org.snmp4j.transport.DefaultUdpTransportMapping$ListenThread.run(Defau
ltUdpTransportMapping.java:282)
My requirement is that if i get an IOException like above I want to
throw that exception and catch it in my code so that i can give a
clearer message. Is it possible to do that? Can anyone of you help me
out with this? Its really urgent.
Thanks a lot!!
Best regards
Shenaz
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