From a24276924875802853b5bdc12c56d29f1c1bbc79 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 20 Mar 2006 18:03:59 -0800 Subject: [PATCH] [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 Signed-off-by: David S. Miller --- include/linux/netfilter/nfnetlink.h | 1 + net/ipv4/netfilter/ip_conntrack_netlink.c | 7 ++++--- net/netfilter/nf_conntrack_netlink.c | 7 ++++--- net/netfilter/nfnetlink.c | 6 ++++++ 4 files changed, 15 insertions(+), 6 deletions(-) diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h index 934a2479f160..9f5b12cf489b 100644 --- a/include/linux/netfilter/nfnetlink.h +++ b/include/linux/netfilter/nfnetlink.h @@ -164,6 +164,7 @@ extern void nfattr_parse(struct nfattr *tb[], int maxattr, __res; \ }) +extern int nfnetlink_has_listeners(unsigned int group); extern int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo); extern int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags); 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; diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index aef3cb41131f..5eadf009bb15 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -338,9 +338,10 @@ 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; diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c index f6063e8f0050..b88e82a1a987 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -191,6 +191,12 @@ nfnetlink_check_attributes(struct nfnetlink_subsystem *subsys, return 0; } +int nfnetlink_has_listeners(unsigned int group) +{ + return netlink_has_listeners(nfnl, group); +} +EXPORT_SYMBOL_GPL(nfnetlink_has_listeners); + int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo) { gfp_t allocation = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL; -- 2.39.5