Patchwork [2/3] netlink: allow to pass data pointer to netlink_dump_start() callback

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Submitter Pablo Neira
Date Feb. 25, 2012, 12:30 a.m.
Message ID <1330129817-28199-3-git-send-email-pablo@netfilter.org>
Download mbox | patch
Permalink /patch/143001/
State Accepted
Delegated to: David Miller
Headers show

Comments

Pablo Neira - Feb. 25, 2012, 12:30 a.m.
From: Pablo Neira Ayuso <pablo@netfilter.org>

This patch allows you to pass a data pointer that can be
accessed from the dump callback.

Netfilter is going to use this patch to provide filtered dumps
to user-space. This is specifically interesting in ctnetlink that
may handle lots of conntrack entries. We can save precious
cycles by skipping the conversion to TLV format of conntrack
entries that are not interesting for user-space.

More specifically, ctnetlink will include one operation to allow
to filter the dumping of conntrack entries by ctmark values.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/linux/netlink.h  |    2 ++
 net/netlink/af_netlink.c |    1 +
 2 files changed, 3 insertions(+), 0 deletions(-)
David Miller - Feb. 26, 2012, 7:27 p.m.
From: pablo@netfilter.org
Date: Sat, 25 Feb 2012 01:30:16 +0100

> From: Pablo Neira Ayuso <pablo@netfilter.org>
> 
> This patch allows you to pass a data pointer that can be
> accessed from the dump callback.
> 
> Netfilter is going to use this patch to provide filtered dumps
> to user-space. This is specifically interesting in ctnetlink that
> may handle lots of conntrack entries. We can save precious
> cycles by skipping the conversion to TLV format of conntrack
> entries that are not interesting for user-space.
> 
> More specifically, ctnetlink will include one operation to allow
> to filter the dumping of conntrack entries by ctmark values.
> 
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Applied.
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Patch

diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 1f8c1a9..a2092f5 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -225,6 +225,7 @@  struct netlink_callback {
 	int			(*dump)(struct sk_buff * skb,
 					struct netlink_callback *cb);
 	int			(*done)(struct netlink_callback *cb);
+	void			*data;
 	u16			family;
 	u16			min_dump_alloc;
 	unsigned int		prev_seq, seq;
@@ -251,6 +252,7 @@  __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
 struct netlink_dump_control {
 	int (*dump)(struct sk_buff *skb, struct netlink_callback *);
 	int (*done)(struct netlink_callback*);
+	void *data;
 	u16 min_dump_alloc;
 };
 
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index ab74845..32bb753 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1750,6 +1750,7 @@  int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 	cb->dump = control->dump;
 	cb->done = control->done;
 	cb->nlh = nlh;
+	cb->data = control->data;
 	cb->min_dump_alloc = control->min_dump_alloc;
 	atomic_inc(&skb->users);
 	cb->skb = skb;