root@opnsense01:~ # cat /usr/local/etc/devd/carp.conf## CARP notify hooks. This will call carpup/carpdown with the# interface (carp0, carp1) as the first parameter.#notify 101 { match "system" "CARP"; match "subsystem" "[0-9]+@[0-9a-z]+"; match "type" "(MASTER|BACKUP)"; action "/usr/local/opnsense/service/configd_ctl.py interface carp $subsystem $type";};root@opnsense01:~ #
rc.syshook "carp" event with "pluginctl -s strongswan restart" should do the trick.