[radvd-devel-l] Advertise Alternate link local address

[Reuben Hawkins]

On Tue, Apr 3, 2012 at 7:55 AM, Seth Mos <seth.mos at dds.nl> wrote:
> Hello,
>
> I am a developer on the pfSense open source firewall based on FreeBSD and I
> need some help with radvd.
>
> In pfSense one can use CARP for high availability so that failure of one
> machine does not result in interruption of service.
>
> This means that there is a shared IPv6 address on the firewalls, just like
> IPv4 and I need to advertise this address to the clients.
>
> That means I need to modify radvd to advertise the CARP link local and
> global address to the clients so the failover is seemless (< 2 seconds
> generally) and all tcp sessions survive.
>
> Because of the nature of the CARP interface in FreeBSD I'm not able to run
> the radvd process on the CARP virtual IP interface as it can not currently
> participate in multicast groups.
>
> That leaves me with the other option, which is run it on the parent
> interface, but advertise the CARP link local and global.
>
> If one can give me some pointers on where to modify radvd for this purpose I
> would appreciate that.
>
> Kind regards,
>
> Seth Mos
> pfSense developer
>
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Hi Seth,

A good place to start would be send_ra in send.c.  This is where the
RA is put together and sent.

Thanks,
Reuben