net: ipv4: notify when address lifetime changes

if userspace changes lifetime of address, send netlink notification and
call notifier.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index f678507..96083b7 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -802,8 +802,10 @@
 		if (nlh->nlmsg_flags & NLM_F_EXCL ||
 		    !(nlh->nlmsg_flags & NLM_F_REPLACE))
 			return -EEXIST;
-
-		set_ifa_lifetime(ifa_existing, valid_lft, prefered_lft);
+		ifa = ifa_existing;
+		set_ifa_lifetime(ifa, valid_lft, prefered_lft);
+		rtmsg_ifa(RTM_NEWADDR, ifa, nlh, NETLINK_CB(skb).portid);
+		blocking_notifier_call_chain(&inetaddr_chain, NETDEV_UP, ifa);
 	}
 	return 0;
 }