snmp__if plugin does not work if server only supports 32 bit counters

The plugin actually supports 32 bit counter as well as 64 bit counter. However, if the snmp server you are connecting to does not support 64 bit byte counters, snmp__if fails.

When I tried to the snmp server which supports only 32 bit counter, the plugin returned as follows:
#munin-run snmp_hostname_if_1
recv.value noSuchObject
send.value noSuchObject

Here is an example of problems I found in the code.

# from line 244
if (defined ($response = $session->get_single($ifEntryIn64Octets) ||
                  $session->get_single($ifEntryInOctets))) {
    print "recv.value ", $response, "\n";
}

In these lines, "$session->get_single($ifEntryIn64Octets" is supposed to return undefined value if the server doesn't support 64 bit counter. However, it actually returns "noSuchObject".

So, these lines should be fixed like this:

if (defined($response = $session->get_single($ifEntryIn64Octets))){
 if ($response eq 'noSuchObject'){
  # 64 bit counter is not supported
  $response = $session->get_single($ifEntryInOctets);
 }
} else {
 # No response
 $response = 'U';
}
print "recv.value ", $response, "\n";

# The information about my environment

Description: Ubuntu 10.04.3 LTS
Release: 10.04

munin-node:
  Installed: 1.4.4-1ubuntu1
  Candidate: 1.4.4-1ubuntu1
  Version table:
 *** 1.4.4-1ubuntu1 0