On Thu, 31 Aug 2017 17:54:05 +0200 Ignacy wrote: IG> I've come across a problem that has been traced down to the way IG> the table helper handlers are processing OIDs. IG> IG> I have a table indexed by a MacAddress. If I pass a short OID, IG> i.e. one that has less bytes than required IG> (say, ...RowStatus.6.1.2.3), at best no error occurs and the IG> missing bytes in the OID are completed with zeroes and at worst IG> my implementation of the table aborts miserably.
Are you using snmpget or snmpgetnext? IG> It appears the problem is caused by the call to IG> parse_one_oid_index() from table_helper_handler() in IG> agent/helpers/table.c. The "complete" argument is set to 1, IG> which means that the missing bytes from the OID are to be IG> completed with zeroes. Then, in IG> netsnmp_table_iterator_helper_handler() IG> (agent/helpers/table_iterator.c), snmp_oid_compare() fails to IG> properly identify the right entry, by comparing a completed OID IG> with an incomplete one. I'm not sure I see the problem here. If you pass and incomplete OID, there is no 'right' entry for a snmpget. IG> I have the impression that the call to parse_one_oid_index() IG> should have the "complete" argument set to 0 instead, so that IG> short OIDs would simply fail as expected. I can't find any IG> explanation for this not being actually the case. The code has IG> been committed in one block in November 2001 with no IG> explanation whatsoever. IG> IG> Does anybody know the reason why such completion should be IG> desirable? If so, it looks IG> netsnmp_table_iterator_helper_handler() needs a fix, but I IG> haven't looked any deeper into it at this time. The compare functions for the helpers expect to have a full OID to compare against. So for short OIDs, zeros are added so the compare functions don't have to deal with logic for lengths. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Net-snmp-coders mailing list Net-snmp-coders@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/net-snmp-coders
