net: ipv6: fix regression of no RTM_DELADDR sent after DAD failure

Commit f784ad3d79e5 ("ipv6: do not send RTM_DELADDR for tentative
addresses") incorrectly assumes that no RTM_NEWADDR are sent for
addresses in tentative state, as this does happen for the standard
IPv6 use-case of DAD failure, see the call to ipv6_ifa_notify() in
addconf_dad_stop(). So as a result of this change, no RTM_DELADDR is
sent after DAD failure for a link-local when strict DAD (accept_dad=2)
is configured, or on the next admin down in other cases. The absence
of this notification breaks backwards compatibility and causes problems
after DAD failure if this notification was being relied on. The
solution is to allow RTM_DELADDR to still be sent after DAD failure.

Fixes: f784ad3d79e5 ("ipv6: do not send RTM_DELADDR for tentative addresses")
Signed-off-by: Mike Manning <mmanning@brocade.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index c2e2a78787ec990f4dac2040fb1e26dc150860e2..d7dbcc8eda10020fa0f1c7ddcf9ad34f00c9f298 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4940,9 +4940,10 @@ static void inet6_ifa_notify(int event, struct inet6_ifaddr *ifa)
 
        /* Don't send DELADDR notification for TENTATIVE address,
         * since NEWADDR notification is sent only after removing
-        * TENTATIVE flag.
+        * TENTATIVE flag, if DAD has not failed.
         */
-       if (ifa->flags & IFA_F_TENTATIVE && event == RTM_DELADDR)
+       if (ifa->flags & IFA_F_TENTATIVE && !(ifa->flags & IFA_F_DADFAILED) &&
+           event == RTM_DELADDR)
                return;
 
        skb = nlmsg_new(inet6_ifaddr_msgsize(), GFP_ATOMIC);