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net: ipv6: fix regression of no RTM_DELADDR sent after DAD failure
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Commit f784ad3 ("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: f784ad3 ("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>
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Mike Manning authored and David S. Miller committed Sep 19, 2017
1 parent 7c30013 commit 6819a14
Showing 1 changed file with 3 additions and 2 deletions.
5 changes: 3 additions & 2 deletions net/ipv6/addrconf.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);
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