[Bug]: Hangs querying OpenBSD

[jwillikers]

Please try to fill out as much of the information below as you can. Thank you!

• Yes, I've searched similar issues on GitHub and didn't find any.

Which version contains the bug?

https://github.com/NETWAYS/check_interfaces/tree/feature/authentication-enhancements

Describe the bug

Querying an OpenBSD system causes the plugin to hang and eventually timeout attempting to obtain the first set of MIBs.
I don't think this issue is related to adding SHA-256 auth support.

The same exact query works with my Linux based systems.

Here is the output of snmpbulkget on the specific OID's being queried when it hangs.

snmpbulkget router .1.3.6.1.2.1.1.3 .1.3.6.1.2.1.2.1 .1.3.6.1.2.1.2.2.1.2
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (5852) 0:00:58.52
IF-MIB::ifNumber.0 = INTEGER: 16
IF-MIB::ifDescr.1 = STRING: em0
SNMPv2-MIB::sysContact.0 = STRING: [email protected]
IF-MIB::ifIndex.1 = INTEGER: 1
IF-MIB::ifDescr.2 = STRING: em1
SNMPv2-MIB::sysName.0 = STRING: router.lan.jwillikers.io
IF-MIB::ifIndex.2 = INTEGER: 2
IF-MIB::ifDescr.3 = STRING: em2
SNMPv2-MIB::sysLocation.0 = STRING: Living_Room
IF-MIB::ifIndex.3 = INTEGER: 3
IF-MIB::ifDescr.4 = STRING: em3
SNMPv2-MIB::sysServices.0 = INTEGER: 76
IF-MIB::ifIndex.4 = INTEGER: 4
IF-MIB::ifDescr.5 = STRING: em4
SNMPv2-MIB::sysORLastChange.0 = Timeticks: (0) 0:00:00.00
IF-MIB::ifIndex.5 = INTEGER: 5
IF-MIB::ifDescr.6 = STRING: em5
SNMPv2-MIB::sysORIndex.1 = INTEGER: 1
IF-MIB::ifIndex.6 = INTEGER: 6
IF-MIB::ifDescr.7 = STRING: enc0
SNMPv2-MIB::sysORIndex.2 = INTEGER: 2
IF-MIB::ifIndex.7 = INTEGER: 7
IF-MIB::ifDescr.8 = STRING: lo0
SNMPv2-MIB::sysORIndex.3 = INTEGER: 3
IF-MIB::ifIndex.8 = INTEGER: 8
IF-MIB::ifDescr.9 = STRING: veb0
SNMPv2-MIB::sysORIndex.4 = INTEGER: 4
IF-MIB::ifIndex.9 = INTEGER: 9
IF-MIB::ifDescr.10 = STRING: vlan2

How to recreate the bug?

$ check_interfaces --auth-proto='SHA-256'  --auth-phrase='****' -h router --priv-proto='AES' --priv-phrase='****' --user='user'
[Starting benchmark] Start SNMP session
[Finished benchmark after 13.318007 ms] Start SNMP session
[Starting benchmark] Send SNMP request for OIDs: .1.3.6.1.2.1.1.3, .1.3.6.1.2.1.2.1, .1.3.6.1.2.1.2.2.1.2
[Finished benchmark after 90080.147729 ms] Send SNMP request for OIDs: .1.3.6.1.2.1.1.3, .1.3.6.1.2.1.2.1, .1.3.6.1.2.1.2.2.1.2
Timeout while reading interface descriptions from router

[RincewindsHat]

curious, on linux I would ask for trying that with strace to see where this is hanging.
Is there an equivalent tool on *bsd?

[jwillikers]

curious, on linux I would ask for trying that with strace to see where this is hanging. Is there an equivalent tool on *bsd?

I think ktrace might be the tool for that. I'll try that. I'm using OpenBSD's native SNMP daemon, too, not Net-SNMP, which might have something to do with it.

[jwillikers]

Okay, I've run ktrace on the snmpd process on the OpenBSD system while running the hanging query. Here's both the debug output of the process and the trace dump.

snmpd-log.txt
snmpd-ktrace-dump.txt.gz

[RincewindsHat]

Sorry, for the delay. I had a look at the logs, but I can't find any good hint.