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Commit eac55bf9 authored by Benoit Boissinot's avatar Benoit Boissinot Committed by David S. Miller
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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: default avatarBenoit Boissinot <benoit.boissinot@ens-lyon.org>
Signed-off-by: default avatarYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c6fbfac2

net/ipv6/addrconf.c

+16 −0
Original line number Diff line number Diff line
@@ -776,6 +776,7 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, struct inet6_ifaddr *i 
	struct inet6_dev *idev = ifp->idev;

	struct in6_addr addr, *tmpaddr;

	unsigned long tmp_prefered_lft, tmp_valid_lft, tmp_cstamp, tmp_tstamp;

	unsigned long regen_advance;

	int tmp_plen;

	int ret = 0;

	int max_addresses;
@@ -836,8 +837,23 @@ retry: 
	tmp_tstamp = ifp->tstamp;

	spin_unlock_bh(&ifp->lock);



	regen_advance = idev->cnf.regen_max_retry *

	                idev->cnf.dad_transmits *

	                idev->nd_parms->retrans_time / HZ;

	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() */

	if (ifp->flags & IFA_F_OPTIMISTIC)