SNMP support in Zephyr

[cbrake]

I'm looking at adding SNMP support to Zephyr. So far I've looked at various Arduino implementations, but they are all C++, and I'd like to avoid that.

Porting pieces of net-snmp seems to be the best approach I've found yet, so working on that.

I don't have anything to share yet, but if anyone has interest, let me know.

[mariopaja]

@cbrake this is a topic that could be interesting for one of our projects. We have kind of skipped it because it was not a hard requirement for the endpoints, but definitely interesting to have it or being able to implement it

[jukkar]

I was looking at this some time ago, but did not had time to work on it.
I think the lwip snmp implementation might be easy to port to zephyr https://github.com/lwip-tcpip/lwip/tree/master/src/apps/snmp

[cbrake]

Thanks for the link -- this does look like a good starting point -- much better than anything I've found yet.

[clamattia]

We are interested in this.

[clamattia]

See also: #2329

[cbrake]

We are starting development in this external module:

https://github.com/simpleiot/zephyr-snmp

@htibosch is currently working on this

Looks like some cleanup will be required to upstream it (converting LWIP stuff to equivalent Zephyr), but hopefully we'll have something usable soon.

[cbrake]

@jukkar with SNMP, we are focusing on:

1. Traps (get sent out)
2. GetRequests (respond to requests)

For #2, would you advise creating an API like the HTTP server with callbacks that fire when requests come in, or is there a better way to do this?

[clamattia]

Have you looked at https://docs.zephyrproject.org/latest/connectivity/networking/api/socket_service.html ?
Could be interesting for system level socket-services like this (see DHCP).

[cbrake]

thanks @clamattia that looks very useful!