Translating pysnmp oids to human readable strings

birdsong david.birdsong at gmail.com
Thu Mar 5 22:05:32 CET 2009


On Mar 5, 12:32 pm, SpamMePlease PleasePlease
<spankthes... at googlemail.com> wrote:
> Hey list,
>
> I was given a task, to reproduce functionality of command specified
> below by writing proper python functions to reuse in some monitoring
> script:
>
> rivendell# snmpwalk -Os -mALL -v1 -cgabilgathol 10.0.6.66
> .1.3.6.1.4.1.2636.5.1.1.2
> jnxBgpM2PeerIdentifier.0.ipv4."".unknown."".0.1.38.101.87.145 =
> STRING: 66.250.1.253
> jnxBgpM2PeerIdentifier.0.ipv4.38.101.161.119.1.38.101.161.118 =
> STRING: 66.28.1.85
> jnxBgpM2PeerIdentifier.0.ipv4.64.200.59.74.1.64.200.59.73 = STRING: 64.200.68.12
> jnxBgpM2PeerIdentifier.0.ipv4.72.37.131.250.1.72.37.131.249 = STRING:
> 64.235.224.240
> jnxBgpM2PeerState.0.ipv4."".unknown."".0.1.38.101.87.145 = INTEGER:
> established(6)
> jnxBgpM2PeerState.0.ipv4.38.101.161.119.1.38.101.161.118 = INTEGER:
> established(6)
> jnxBgpM2PeerState.0.ipv4.64.200.59.74.1.64.200.59.73 = INTEGER: established(6)
> jnxBgpM2PeerState.0.ipv4.72.37.131.250.1.72.37.131.249 = INTEGER: established(6)
> (more output)
>
> I have already found a pysnmp library to fetch the data from the
> device with a minimal amount of code:
>
> from pysnmp.entity.rfc3413.oneliner import cmdgen
> from pysnmp.smi import *
> import string
>
> cmdGen = cmdgen.CommandGenerator()
> errorIndication, errorStatus, errorIndex, varBinds =
> cmdgen.CommandGenerator().nextCmd(cmdgen.CommunityData('AmonMuil',
> 'gabilgathol', 0),
> cmdgen.UdpTransportTarget(('fw-1.datacenter.gondor.net', 161)),
> (1,3,6,1,4,1,2636,5,1,1,2))
>
> print errorIndication, errorStatus
> for i in varBinds:
>     print i
>
> The problem is that I have completely stuck on the result I am
> experiencing being totally human unreadable, like this:
>
> rivendell# python snmp.py
> None 0
> [(ObjectName('1.3.6.1.4.1.2636.5.1.1.2.1.1.1.1.0.1.0.0.0.0.1.38.101.87.145'),
> OctetString('B\xfa\x01\xfd'))]
> [(ObjectName('1.3.6.1.4.1.2636.5.1.1.2.1.1.1.1.0.1.38.101.161.119.1.38.101.161.118'),
> OctetString('B\x1c\x01U'))]
> [(ObjectName('1.3.6.1.4.1.2636.5.1.1.2.1.1.1.1.0.1.64.200.59.74.1.64.200.59.73'),
> OctetString('@\xc8D\x0c'))]
> [(ObjectName('1.3.6.1.4.1.2636.5.1.1.2.1.1.1.1.0.1.72.37.131.250.1.72.37.131.249'),
> OctetString('@\xeb\xe0\xf0'))]
> [(ObjectName('1.3.6.1.4.1.2636.5.1.1.2.1.1.1.2.0.1.0.0.0.0.1.38.101.87.145'),
> Integer32('6'))]
> [(ObjectName('1.3.6.1.4.1.2636.5.1.1.2.1.1.1.2.0.1.38.101.161.119.1.38.101.161.118'),
> Integer32('6'))]
> [(ObjectName('1.3.6.1.4.1.2636.5.1.1.2.1.1.1.2.0.1.64.200.59.74.1.64.200.59.73'),
> Integer32('6'))]
> [(ObjectName('1.3.6.1.4.1.2636.5.1.1.2.1.1.1.2.0.1.72.37.131.250.1.72.37.131.249'),
> Integer32('6'))]
> [(ObjectName('1.3.6.1.4.1.2636.5.1.1.2.1.1.1.3.0.1.0.0.0.0.1.38.101.87.145'),
> Integer32('2'))]
>
> Since I cant find any way to translate these numbers to the same thing
> snmpwalk produce, is there any clue on how to achieve that? Is it
> possible at all for different devices (this one happend to be Juniper
> firewall if that does matter). Also, how can I know where does this
> magic oid ends and where does additional information starts (like ip
> addresses added to oid 0 they all looks like another oid string
> numbers) ?
>
> Any sample of code, or hint to another lib will be very appreciated!
>
> --
> --------------------
> Spank The Spam!

Here's an example of walk that's part of a class I wrote, hopefully
indentation survives the paste.  I borrowed heavily from example code
on the pysnmp site.

from pysnmp import asn1, v2c
from pysnmp import role

  def walk(self, community_string, base_oids):

    if type(base_oids) is str: base_oids = [base_oids]
    # this this does what it says, dont bother asking for oids that
we'll see in our walk
    base_oids = self.remove_child_oids(base_oids)
    # h_pair is just (host, port)
    client = role.manager(self.h_pair)
    client.timeout = 10
    req = v2c.GETNEXTREQUEST(community=community_string)
    rsp = v2c.GETRESPONSE()
    req['encoded_oids'] = map(asn1.OBJECTID().encode, base_oids)

    oids_values = {}
    while req['encoded_oids']:
      try:
        answer, host_tuple = client.send_and_receive(req.encode())
      except (role.NoResponse, role.NetworkError):
        return oids_values

      rsp.decode(answer)

      parsed_oids_vals = self.parse_response(rsp, base_oids)
      oids_values.update(parsed_oids_vals)

      req['request_id'] += 1
      req['encoded_oids'] = map(asn1.OBJECTID().encode,
parsed_oids_vals.keys())

    return oids_values




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