netlink: allow to pass data pointer to netlink_dump_start() callback (7175c883) · Commits · 戴 / test

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> Signed-off-by:

David S. Miller <davem@davemloft.net>

include/linux/netlink.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -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;
		};

net/netlink/af_netlink.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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;

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