ipv6: resend MLD report if a link-local address completes DAD

RFC3590/RFC3810 specifies we should resend MLD reports as soon as a
valid link-local address is available.

We now use the valid_ll_addr_cnt to check if it is necessary to resend
a new report.

Changes since Flavio Leitner's version:
a) adapt for valid_ll_addr_cnt
b) resend first reports directly in the path and just arm the timer for
   mc_qrv-1 resends.

Reported-by: Flavio Leitner <fleitner@redhat.com>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: David Stevens <dlstevens@us.ibm.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Flavio Leitner <fbl@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 1628b8f..736b5fb 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -174,10 +174,12 @@
 	unsigned char		mc_qrv;
 	unsigned char		mc_gq_running;
 	unsigned char		mc_ifc_count;
+	unsigned char		mc_dad_count;
 	unsigned long		mc_v1_seen;
 	unsigned long		mc_maxdelay;
 	struct timer_list	mc_gq_timer;	/* general query timer */
 	struct timer_list	mc_ifc_timer;	/* interface change timer */
+	struct timer_list	mc_dad_timer;	/* dad complete mc timer */
 
 	struct ifacaddr6	*ac_list;
 	rwlock_t		lock;