Created attachment 213122 [details]
Since radvd 2.x update some deployments reach the following error:
Apr 6 11:16:48 XXX radvd: can't join ipv6-allrouters on em0
Apr 6 11:17:04 XXX radvd: IPv6 forwarding on interface seems to be disabled, but continuing anyway
Apr 6 11:17:04 XXX radvd: can't join ipv6-allrouters on em0
And router advertisements are no longer sent.
This happens because the FreeBSD bsd44 patch to join multicast is now called multiple times for the same interface. The first call goes well, the others error out because the join error means that the multicast group is already joined. To remedy this issue simply leave the group unconditionally in order to let the rejoin work all the time.
This makes radvd 2.x behave like 1.x in OPNsense IPv6 environments.
While here, squelch the "IPv6 forwarding on interface seems to be disabled, but continuing anyway" message because it has no programmatic consequence and the flag is not supported on BSD anyway.
A commit references this bug:
Date: Thu Apr 9 20:31:46 UTC 2020
New revision: 531270
net/radvd: fix group join fail on multiple tries
Submitted by: Franco Fichtner <firstname.lastname@example.org>