提交 a2427692 编写于 作者: P Patrick McHardy 提交者: David S. Miller

[NETFILTER]: ctnetlink: avoid unneccessary event message generation

Avoid unneccessary event message generation by checking for netlink
listeners before building a message.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 c4b88513
......@@ -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);
......
......@@ -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;
......
......@@ -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;
......
......@@ -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;
......
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