Re: [pysnmp-users] pysnmp / pyasn1 decode problem with multi-line traps
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Re: [pysnmp-users] pysnmp / pyasn1 decode problem with multi-line traps
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From: Ilya E. <il...@gl...> - 2015-03-10 06:03:20
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Hi Tom,
The OctetString type prints its contents in hex form if there’s a potentially non-printable characters there that may be lost when printing to the terminal. Use .asOctets() method to retrieve data in pure octet-string form:
>>> s = OctetString(hexValue='4f70657261746f722058585858585858585858203a20585858585858585858582c2058585858585858202c204c6f63616c6c792061757468656e74696361746564202d207375636365737366756c6c79207369676e6564206f6e20746f20746865207465726d696e616c20275858582e5858582e582e584058272061742031343a3238207573696e672027585858585858585820585858205858585858585858272e0a4f70657261746f722050726f66696c65733a2058585858585858585858585858')
>>> s.prettyPrint()
'0x4f70657261746f722058585858585858585858203a20585858585858585858582c2058585858585858202c204c6f63616c6c792061757468656e74696361746564202d207375636365737366756c6c79207369676e6564206f6e20746f20746865207465726d696e616c20275858582e5858582e582e584058272061742031343a3238207573696e672027585858585858585820585858205858585858585858272e0a4f70657261746f722050726f66696c65733a2058585858585858585858585858'
>>> s.asOctets()
"Operator XXXXXXXXXX : XXXXXXXXXX, XXXXXXX , Locally authenticated - successfully signed on to the terminal 'XXX.XXX.X.X@X' at 14:28 using 'XXXXXXXX XXX XXXXXXXX'.\nOperator Profiles: XXXXXXXXXXXXX"
-ilya
> On 09 Mar 2015, at 22:23, Tom Kr. <to...@we...> wrote:
>
>
> Hi there,
>
> I'm new to this mailing list and I have a issue with the pysnmp / pyasn1 module.
> I use python with version 3.4 and pysnmp with version 4.2.5.
> The OS is Ubuntu server 14.04.2.
>
> # lsb_release -a
> No LSB modules are available.
> Distributor ID: Ubuntu
> Description: Ubuntu 14.04.2 LTS
> Release: 14.04
> Codename: trusty
>
> ii python-pysnmp4 4.2.5-1 all Python SNMP library for agents and managers (Python 2 module)
> ii python-pyasn1 0.1.7-1ubuntu2 all ASN.1 library for Python (Python 2 module)
> ii python3.4 3.4.0-2ubuntu1 amd64 Interactive high-level object-oriented language (version 3.4)
>
> I try to use the following script to read snmp traps and print this traps on the screen.
> But unfortunately I have some troubles with multi-line traps.
> This traps are only shown as hex values.
> I think the problem is the decoder but I'm not very familiar with python and also not with pysnmp.
>
> I hope someone of you can help me or give me some ideas what I should do next.
> For the moment I have no idea.
>
> The script:
> ----------------------------------------------------------------------------------------------
> import sys,os
>
> sys.path.append('/usr/share/pyshared/')
>
> from pysnmp.carrier.asynsock.dispatch import AsynsockDispatcher
> from pysnmp.carrier.asynsock.dgram import udp, udp6
> from pyasn1.codec.ber import decoder
> from pysnmp.proto import api
>
> def trapCallback(transportDispatcher, transportDomain, transportAddress, wholeMsg):
> while wholeMsg:
> msgVer = int(api.decodeMessageVersion(wholeMsg))
> if msgVer in api.protoModules:
> pMod = api.protoModules[msgVer]
> else:
> print('Unsupported SNMP version %s' % msgVer)
> return
> reqMsg, wholeMsg = decoder.decode(
> wholeMsg, asn1Spec=pMod.Message(),
> )
> print('Notification message from %s:%s: ' % (
> transportDomain, transportAddress
> )
> )
> reqPDU = pMod.apiMessage.getPDU(reqMsg)
> if reqPDU.isSameTypeWith(pMod.TrapPDU()):
> if msgVer == api.protoVersion1:
> print('Enterprise: %s' % (
> pMod.apiTrapPDU.getEnterprise(reqPDU).prettyPrint()
> )
> )
> print('Agent Address: %s' % (
> pMod.apiTrapPDU.getAgentAddr(reqPDU).prettyPrint()
> )
> )
> print('Generic Trap: %s' % (
> pMod.apiTrapPDU.getGenericTrap(reqPDU).prettyPrint()
> )
> )
> print('Specific Trap: %s' % (
> pMod.apiTrapPDU.getSpecificTrap(reqPDU).prettyPrint()
> )
> )
> print('Uptime: %s' % (
> pMod.apiTrapPDU.getTimeStamp(reqPDU).prettyPrint()
> )
> )
> varBinds = pMod.apiTrapPDU.getVarBindList(reqPDU)
> else:
> varBinds = pMod.apiPDU.getVarBindList(reqPDU)
> print('Var-binds:')
> for oid, val in varBinds:
> print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
> return wholeMsg
>
> transportDispatcher = AsynsockDispatcher()
>
> transportDispatcher.registerRecvCbFun(trapCallback)
>
> # UDP/IPv4
> transportDispatcher.registerTransport(
> udp.domainName, udp.UdpSocketTransport().openServerMode(('localhost', 162))
> )
>
> # UDP/IPv6
> transportDispatcher.registerTransport(
> udp6.domainName, udp6.Udp6SocketTransport().openServerMode(('::1', 162))
> )
>
> transportDispatcher.jobStarted(1)
>
> try:
> # Dispatcher will never finish as job#1 never reaches zero
> transportDispatcher.runDispatcher()
> except:
> transportDispatcher.closeDispatcher()
> raise
> ----------------------------------------------------------------------------------------------
>
>
> As you can see, the script is an example from the project side.
> (http://pysnmp.sourceforge.net/examples/current/v1arch/manager/ntfrcv/v2c-multiple-transports.html <http://pysnmp.sourceforge.net/examples/current/v1arch/manager/ntfrcv/v2c-multiple-transports.html>)
>
> This is the part of the trap where the hex value is shown instead of the plain text.
> string=0x4f70657261746f722058585858585858585858203a20585858585858585858582c2058585858585858202c204c6f63616c6c792061757468656e74696361746564202d207375636365737366756c6c79207369676e6564206f6e20746f20746865207465726d696e616c20275858582e5858582e582e584058272061742031343a3238207573696e672027585858585858585820585858205858585858585858272e0a4f70657261746f722050726f66696c65733a2058585858585858585858585858
>
> This is the message I would expect.
> "Operator XXXXXXXXXX : XXXXXXXXXX, XXXXXXX , Locally authenticated - successfully signed on to the terminal 'XXX.XXX.X.X@X' at 14:28 <x-apple-data-detectors://4>using 'XXXXXXXX XXX XXXXXXXX'.
> Operator Profiles: XXXXXXXXXXXXX"
>
> For me, the problem is located at the line feed. Is there a possibility to replace any line feed character with a space or nothing?
> I think this should be done in the pyasn1 module, but I don't know how.
>
> Hope somebody can help me with my problem.
>
> Kind regards,
> Tom
>
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