Re: MAC Address As Index

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


BTW, somehow the response from Neils is missed but found it in the archive.
https://www.mail-archive.com/[email protected]/msg21705.html

MacAddress TC from SNMPv2-TC is a fixed size string, so, the length
should not be prefixed.