From 4277a083ecd2c8771058641132bcecea04ca6608 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 20 Mar 2006 18:52:01 -0800 Subject: [NETLINK]: Add netlink_has_listeners for avoiding unneccessary event message generation Keep a bitmask of multicast groups with subscribed listeners to let netlink users check for listeners before generating multicast messages. Queries don't perform any locking, which may result in false positives, it is guaranteed however that any new subscriptions are visible before bind() or setsockopt() return. Signed-off-by: Patrick McHardy ACKed-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- include/linux/netlink.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/netlink.h') diff --git a/include/linux/netlink.h b/include/linux/netlink.h index c256ebe2a7b4..f8f3d1c927f8 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -151,6 +151,7 @@ struct netlink_skb_parms extern struct sock *netlink_kernel_create(int unit, unsigned int groups, void (*input)(struct sock *sk, int len), struct module *module); extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err); +extern int netlink_has_listeners(struct sock *sk, unsigned int group); extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock); extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid, __u32 group, gfp_t allocation); -- cgit v1.2.2