Re: [PATCH] ipv6: Add IFA_F_DADFAILED flag

[Jens Rosenboom <jens@mcbone.net>]

On Tue, 2009-09-08 at 11:18 -0400, Brian Haley wrote:
> Jens Rosenboom wrote:
> >> --- a/net/ipv6/addrconf.c
> >> +++ b/net/ipv6/addrconf.c
> >> @@ -1376,7 +1376,7 @@ static void addrconf_dad_stop(struct inet6_ifaddr *ifp)
> >>  	if (ifp->flags&IFA_F_PERMANENT) {
> >>  		spin_lock_bh(&ifp->lock);
> >>  		addrconf_del_timer(ifp);
> >> -		ifp->flags |= IFA_F_TENTATIVE;
> >> +		ifp->flags |= IFA_F_DADFAILED;
> > 
> > I think you still have to set IFA_F_TENTATIVE here, too, otherwise
> > ipv6_dev_get_saddr() will use this address. 		
> 
> The tentative bit is still set from when this address was added back
> in ipv6_add_addr() from what I can tell, re-setting it here is actually
> unnecessary.  At least /sbin/ip was still showing it set during my
> testing.

There is the possibility of a race when the dad_timer expires at the
same time the NA triggering DAD failure is received. There isn't a big
chance to see that during real world testing, though.