net/frr: watchfrr service handling

[AndyX90]

This commit fixes CARP event handler integration with FRR service startup.
It resolves issues with triggering the CARP event handler during service startup, particularly in setups where route costs depend on CARP status.

• Removes the "start_postcmd" override, as routing deamon lifecycle management is now handled by watchfrr.
• Introduces two service wrapper scripts to hook into watchfrr's startup and restart procedures.

More information on actual startup behavior:
https://cgit.freebsd.org/ports/tree/net/frr8/files/frr.in#n15
https://cgit.freebsd.org/ports/tree/net/frr8/files/watchfrr.in#n25

Tested Scenarios (correct costs applied):
✓ Stopping / Starting FRR
✓ Killing ospfd process
✓ Reboot
✓ Service reload through frr-reload.py

Resolves #4702

[AdSchellevis]

at a first glance this looks fine, but I rather have a single wrapper script in stead of two.

[AndyX90]

@AdSchellevis This one works!
Note: It also removes the old 50-frr start syshook. It is not needed anymore and produces errors on startup:
>>> Error in start script '50-frr'

EDIT: Another option instead of removal could've been to change it to something like the carp syshook:
... shell_exec('/usr/local/opnsense/scripts/frr/carp_event_handler'); ...

[fichtner]

it's ok to try and ditch this, but it's also hard to predict that this isn't needed anymore because it handles a startup error edge case. Functionally this shouldn't matter. If we are worried about the error being shown a || true would do the trick, or checking if already running before starting. But only commenting here for future us. ;)

[AndyX90]

Changes:

• the wrapper now catches the exit code of the service and returns it to watchfrr.
• actions_quagga.conf changed accordingly
• added copyright header

I would try to omit the start syshook, because watchfrr is now enabled by default and should handle such a case.
If I'm not mistaken this was because of (sub)process startup issues.

[fichtner]

thanks

[AndyX90]

Pushed the wrong one 😅
So i think this is the safest version.
It uses the startup syshook to invoke the carp_event_handler on successful startup through rc and internally watchfrr start/restarts are handled.
If you are okay with this @fichtner and @AdSchellevis then this is the one.

Note: The startup now is taken from the carp hook. This is not explicitly required, but i noticed sometimes some weird timing issues on reboot, when the service starts and watchfrr starts the all the services. It safeguards the setting of needed costs.

[AndyX90]

Changes:

• added syslog filter definition for frr_wrapper