[NETFILTER]: ctnetlink: avoid unneccessary event message generation

Avoid unneccessary event message generation by checking for netlink
listeners before building a message.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 3 deletions

diff --git a/net/ipv4/netfilter/ip_conntrack_netlink.c b/net/ipv4/netfilter/ip_conntrack_netlink.c
index e0b5926c76f9..5ce2e3fc2c7f 100644
--- a/net/ipv4/netfilter/ip_conntrack_netlink.c
+++ b/net/ipv4/netfilter/ip_conntrack_netlink.c
@@ -327,9 +327,10 @@ static int ctnetlink_conntrack_event(struct notifier_block *this,
                 group = NFNLGRP_CONNTRACK_UPDATE;
         } else 
                 return NOTIFY_DONE;
-        
-  /* FIXME: Check if there are any listeners before, don't hurt performance */
-        
+
+        if (!nfnetlink_has_listeners(group))
+                return NOTIFY_DONE;
+
         skb = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
         if (!skb)
                 return NOTIFY_DONE;