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>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index e11f10e..e7a1882 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -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 long regen_advance;
int tmp_plen;
int ret = 0;
int max_addresses;
@@ -836,8 +837,23 @@
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)