kern/127050: [carp] ipv6 does not work on carp interfaces [regression]

[Paul Herman]

The following reply was made to PR kern/127050; it has been noted by GNATS.

From: Paul Herman <pherman at frenchfries.net>
To: bug-followup at FreeBSD.org
Cc: Wouter de Jong <maddog2k at maddog2k.net>, Jacek Zapala <jacek at it.pl>
Subject: Re: kern/127050: [carp] ipv6 does not work on carp interfaces [regression]
Date: Fri, 19 Aug 2011 10:13:46 +0200

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 This one's been bothering me too, so I setup a test machine yesterday to 
 figure out what's going on.  I see two problems here.
 
 First of all, in6_ifinit() (called via in6_control() SIOCAIFADDR_IN6 -> 
 in6_update_ifa()) only calls carp_ioctl() on the first IPv6 address. 
 Whereas in the v4 case, carp_ioctl() does get called by in_ifinit() 
 every time.
 
 Second of all, carp_set_addr6() (called via carp_ioctl()) only joins the 
 CARP multicast group AND the solicitation group with the first address.
 
 The attached patch against 8-STABLE fixes these issues, alias IPs are 
 now pingable.  I have not tested actual carp functionality with a 2nd 
 BACKUP carp.  What this patch doesn't address is group membership 
 removal when alias IPs are deleted (apparently also broken.)
 
 Try it out, if it works for you guys, maybe someone more familiar with 
 in[6]_control() can chime in here and comment on a *real* way to fix 
 this issue.  :-)
 
 Cheers,
 
 -Paul.
 
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