Re: MAC Address As Index

You can do this if you use snmp_varlist_add_variable() to create the index
info (you can't use netsnmp_table_helper_add_indexes).  The code would be
something like

    table_info = SNMP_MALLOC_TYPEDEF( netsnmp_table_registration_info );
    snmp_varlist_add_variable(&table_info->indexes,
                                  NULL,
                                  0,
                                  ASN_TYPE_OF_IFACE_NAME,
                                  NULL,
                                  0);
    snmp_varlist_add_variable(&table_info->indexes,
                                  NULL,
                                  0,
                                  ASN_IMPLIED_OCTET_STR,
                                  "XXXXXX",
                                  6);
    snmp_varlist_add_variable(&table_info->indexes,
                                  NULL,
                                  0,
                                  ASN_TYPE_OF_HIST_CLASS,
                                  NULL,
                                  0);
    snmp_varlist_add_variable(&table_info->indexes,
                                  NULL,
                                  0,
                                  ASN_TYPE_OF_HISTBIN_INDEX,
                                  NULL,
                                  0);


  Bill


On Mon, Sep 16, 2019 at 10:23 AM Krishna Chaitanya <[email protected]>
wrote:

> On Tue, Sep 3, 2019 at 5:23 PM Krishna Chaitanya
> <[email protected]> wrote:
> >
> > On Tue, Aug 27, 2019 at 2:12 PM Krishna Chaitanya
> > <[email protected]> wrote:
> > >
> > > On Mon, Aug 26, 2019 at 9:22 PM Bill Fenner <[email protected]> wrote:
> > > >
> > > > On Tue, Aug 20, 2019 at 8:45 AM Krishna Chaitanya <
> [email protected]> wrote:
> > > >>
> > > >> Hi,
> > > >>
> > > >> When using MAC Address as an index ( I am using MacAddress type from
> > > >> SNMPv2-TC.) the output is incorrect because the length of the string
> > > >> is prefixed as mac address is defined as OCTET STR there is an extra
> > > >> byte and the last byte of mac address is interpreted as next OID.
> > > >>
> > > >> snmpwalk:
> > > >>    HistValue."wlp8s0f0".'....B.'.hist_2.2.19
> > > >> snmpwalk -OX
> > > >>   HistValue["wlp8s0f0"][STRING: 06:00:90:e6:42:99][hist_2][2].19
> > > >>
> > > >> In the above examples last but one OID 2 is hist_2. Is there a way
> to
> > > >> disable prefixing of length?
> > > >
> > > >
> > > > The prefixing of length is done by the agent.  Are you asking about
> a MIB module that you implemented?  Try changing your object definition
> from ASN_OCTET_STR to ASN_PRIV_IMPLIED_OCTET_STR.
> > > Yes, I am using my own MIB and changing to ASN_PRIV_IMPLIED_OCTET_STR
> > > in the subagent worked.
> > > Thanks, Bill.
> >
> > After this change, I was getting a lot of duplicate data exists
> > errors, upon further debugging found a similar issue
> > which is quite old
> >
> https://www.mail-archive.com/[email protected]/msg06286.html
> .
> > In the current code even though there is support to handle IMPLIED
> > strings, but subsequent indexes are not processed.
> > See snippet below: out of 4 indexes only 2 are processed (the indexes
> > after ASN_PRIV_IMPLIED_OCTET_STR
> > failed to parse. Any ideas?
> >
> > histStatsData: Request Mode is: 160 name: wlp8s0f0 col: 3
> > histStatsData: Add row
> > duplicate table data attempted to be entered. row exists
> > helper:table:req: Got GETNEXT (161) mode request for handler table:
> > base oid:SNMPv2-SMI::mib-2.43932.2.2
> > helper:table:col:   have at least a column (3)
> > helper:table:     have 17 bytes of index
> > helper:table:   looking for 4 indexes
> >
> > parse_oid_indexes: Parsed str(4): wlp8s0f0
> > helper:table:   got 1 (incomplete=0)
> >
> > parse_oid_indexes: Parsed str(196):
> > helper:table:   got 1 (incomplete=0)
> >
> > helper:table:   oid indexes not complete:
> >
> SNMPv2-SMI::mib-2.43932.2.2.1.3.8.119.108.112.56.115.48.102.48.0.128.225.66.153.1.2.15
> > helper:table:results:   found 2 indexes
> > helper:table:results:   column: 3, indexes: 2   index: type=4(04),
> > value=STRING: "wlp8s0f0"   index: type=196(c4), value=Variable has bad
> > type
> >
>
> As a workaround moved the MAC address index to last and it works fine
> with ASN_IMPLIED_OCTER_STR, this should be good enough for parsing
> programmatically, but
> for end-user its a bit counter-intuitive, having MAC Address as the
> 2nd index out of 4 is
> more readable. This was the diff in MIB:
>
> -  INDEX { ifaceName, remoteMAC, HistClass, HistBinIndex}
> +  INDEX { ifaceName, HistClass, HistBinIndex, remoteMAC}
>

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