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authorPatrick McHardy <kaber@trash.net>2006-03-20 18:52:01 -0800
committerDavid S. Miller <davem@davemloft.net>2006-03-20 18:52:01 -0800
commit4277a083ecd2c8771058641132bcecea04ca6608 (patch)
treec35d659c63fa4d64e2569e5eebd76e1b3fba9a15 /include
parenta24276924875802853b5bdc12c56d29f1c1bbc79 (diff)
downloadop-kernel-dev-4277a083ecd2c8771058641132bcecea04ca6608.zip
op-kernel-dev-4277a083ecd2c8771058641132bcecea04ca6608.tar.gz
[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 <kaber@trash.net> ACKed-by: Jamal Hadi Salim<hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/linux/netlink.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index c256ebe..f8f3d1c 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);
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