In article <268e602e19080797193e.1206305171@pirzuine> (at Sun, 23 Mar 2008 21:46:11 +0100), Benoit Boissinot <benoit.boissinot@ens-lyon.org> says:

quoted text
> IPv6: do not create temporary adresses with too short preferred lifetime
> 
> >From RFC341:
> A temporary address is created only if this calculated Preferred
> Lifetime is greater than REGEN_ADVANCE time units.  In particular,
> an implementation must not create a temporary address with a zero
> Preferred Lifetime.
> 
> Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org>
> 
> diff -r 5e50b19fbb75 -r 268e602e1908 net/ipv6/addrconf.c
> --- a/net/ipv6/addrconf.c	Sat Mar 22 00:41:39 2008 +0100
> +++ b/net/ipv6/addrconf.c	Sat Mar 22 00:39:16 2008 +0100
> @@ -776,6 +776,7 @@
>  	struct inet6_dev *idev = ifp->idev;
>  	struct in6_addr addr, *tmpaddr;
>  	unsigned long tmp_prefered_lft, tmp_valid_lft, tmp_cstamp, tmp_tstamp;
> +	unsigned int regen_advance;

unsigned long

quoted text
>  	int tmp_plen;
>  	int ret = 0;
>  	int max_addresses;
> @@ -834,9 +835,24 @@
>  	max_addresses = idev->cnf.max_addresses;
>  	tmp_cstamp = ifp->cstamp;
>  	tmp_tstamp = ifp->tstamp;
> +	regen_advance = idev->cnf.regen_max_retry *
> +	                idev->cnf.dad_transmits *
> +	                idev->nd_parms->retrans_time / HZ;
>  	spin_unlock_bh(&ifp->lock);

regen_advance can be outside of the lock of ifp.

quoted text
>  	write_unlock(&idev->lock);
> +
> +	/* A temporary address is created only if this calculated Preferred
> +	 * Lifetime is greater than REGEN_ADVANCE time units.  In particular,
> +	 * an implementation must not create a temporary address with a zero
> +	 * Preferred Lifetime.
> +	 */
> +	if (tmp_prefered_lft <= regen_advance) {
> +		in6_ifa_put(ifp);
> +		in6_dev_put(idev);
> +		ret = -1;
> +		goto out;
> +	}
>  
>  	addr_flags = IFA_F_TEMPORARY;
>  	/* set in addrconf_prefix_rcv() */

Otherwise, I agree.

--yoshfuji
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html