Ipv6 dhcp issues with bridge as track interface

[PertFlavus]

Any chance we can get these two taken care of for the 2.4 release? ipv6 is much more common now. I think more people will run into this.
https://redmine.pfsense.org/issues/6529
https://redmine.pfsense.org/issues/3965

[jimp]

IPv6 may be more common, but bridging is not (and shouldn't be).

Also it looks like, from those errors, the problem is not one we can fix, it's a problem in the underlying program not understanding bridge interfaces.

[hertle]

@jimp:

Also it looks like, from those errors, the problem is not one we can fix, it's a problem in the underlying program not understanding bridge interfaces.

I ran into this problem today and did some debugging with the log files. It seems that the WAN interface is configured first and the bridge is created afterwards. So dhcp6c is started when the bridge does not exist yet:

From syslog (dhcp6c is started in line 6, the bridge is configured at the end):

Jul 19 21:41:55 vali kernel: igb0: link state changed to UP
Jul 19 21:41:55 vali check_reload_status: Linkup starting igb0
Jul 19 21:41:56 vali check_reload_status: rc.newwanip starting igb0
Jul 19 21:41:56 vali php-cgi: rc.bootup: Accept router advertisements on interface igb0 
Jul 19 21:41:56 vali rtsold: Received RA specifying route fe80::3a10:d5ff:fe0f:4568 for interface wan(igb0)
Jul 19 21:41:56 vali rtsold: Starting dhcp6 client for interface wan(igb0)
Jul 19 21:41:57 vali php-fpm[282]: /rc.newwanip: rc.newwanip: Info: starting on igb0.
Jul 19 21:41:57 vali php-fpm[282]: /rc.newwanip: rc.newwanip: on (IP address: 172.16.0.4) (interface: WAN[wan]) (real interface: igb0).
Jul 19 21:41:57 vali kernel: done.
Jul 19 21:41:59 vali kernel: done.
Jul 19 21:41:59 vali kernel: bridge0: Ethernet address: 02:3a:f6:9b:b6:00
Jul 19 21:41:59 vali kernel: bridge0: link state changed to UP

Here is the according dhcp log:

Jul 19 21:41:56 	dhcp6c 	11476 	failed to parse configuration file
Jul 19 21:41:56 	dhcp6c 	11476 	called
Jul 19 21:41:56 	dhcp6c 	11476 	/var/etc/dhcp6c_wan.conf:14 invalid interface (bridge0): Device not configured
Jul 19 21:41:56 	dhcp6c 	11476 	<3>end of sentence [;] (1)
Jul 19 21:41:56 	dhcp6c 	11476 	<3>end of closure [}] (1)
Jul 19 21:41:56 	dhcp6c 	11476 	<3>end of sentence [;] (1)
Jul 19 21:41:56 	dhcp6c 	11476 	<3>end of closure [}] (1)
....

Comparing the timestamps you see that dhcp6c tries to use bridge0 before it is up.

[PertFlavus]

Can I suggest a warning on the bridge setup page at a minimum? The ipv6 issue is not obvious at all. I had been running this config for over a year without realizing why my internet kept breaking so particularly…