Subject: Re: primary and secondary ip addresses

From: Thomas Graf <[email-masked]>
Date: Sun, 19 Dec 2004 23:02:11 +0100

* Harald Welte <[email-masked]> 2004-12-19 22:41
> On Sun, Dec 19, 2004 at 03:18:37PM -0500, jamal wrote:
> 
> > Having said the above, I think it would make sense to have a "promotion"
> > scheme so that in the case a primary address is deleted, one could
> > promote the next secondary address in line. But that should be optional.
> 
> Oh yes, please.  This would save a lot of headache.  I'm much in favour
> of such a proposal.

Agreed, would be nice to have.

> > Now where is the fireman who wants to do this? I could help cheering
> > since i know the code.
> 
> how would you think it fits best into the current netlink messages?

 1) IFA_F_PROM_CAND flag and have inet_del_ifa* iterate over its
    secondary addresses and elect the first with the flag set.

 2) IFA_PROM_PRIO TLV of type u32 holding a priority where 0 means no
    candiate. inet_del_ifa* iterates over its secondary addresses and
    elects the one with the highest prio as new primary address or
    deletes all addresses if none is found.

* respectively the equivalent function of the other address families.

Second variant requires more work but is more flexible so it's
definitely my favourite. I'm willing to put some effort into this,
I'm not familiar with all address families though.