Re: Notification of change of IP address/Routing etc

> On 31 Aug 2022, at 10:11, Martin Stiemerling <mls.ietf@gmail.com> wrote:
> 
> Hi, 
> 
>> Am 31.08.2022 um 11:00 schrieb Peter Jeremy <peterj@freebsd.org>:
>> 
>> On 2022-Aug-31 10:18:44 +0200, Martin Stiemerling <mls.ietf@gmail.com> wrote:
>>> I am looking for a mechanism to get a notification from the OS when, for instance, an IP address on an interface or a routing entry is being changed. 
>> 
>> Assuming you are using the base OS version of dhclient, you could use
>> /etc/dhclient-exit-hooks, which is a shellscript documented in
>> dhclient-script(8).
> 
> Thanks, but that won’t help, as I need notifications about all changes, even if the change is not happening thru dhcp. E.g., IPv6 changes or manual changes. 
> 
> This is for a gnmi-target, i.e., net management via yang/gnmi, under development for Linux and FreeBSD for routers, firewalls, software switches etc:
> https://code.fbi.h-da.de/danet/gnmi-target
> 
> I have seen that there is a project for adding netlink to FreeBSD14: https://github.com/pengnam/freebsd-netlink
> 
> Right now, I haven’t found a way, devd is for device changes only, to get this done. 
For now, you can use routing socket notifications (route(4)).
"route -n monitor” provide a quick way to check what’s available at the moment.

There are some plans to have netlink in 14 and 13 but the timeframe is not settled yet.
> 
> I am happy to help to change this, but it is unclear to me where and how to start. 
> 
> Thanks,
> 
>  Martin 
> 
> 
> 
>