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netfilter: ctnetlink: support kernel-space dump filtering by ctmark

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This patch adds CTA_MARK_MASK which, together with CTA_MARK, allows
you to selectively send conntrack entries to user-space by
returning those that match mark & mask.

With this, we can save cycles in the building and the parsing of
the entries that may be later on filtered out in user-space by using
the ctmark & mask.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Pablo Neira Ayuso
2012-02-24 14:41:50 +00:00
committed by David S. Miller
parent 7175c88307
commit 0f298a285f
2 changed files with 35 additions and 1 deletions
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1
include/linux/netfilter/nfnetlink_conntrack.h
View File

@@ -43,6 +43,7 @@ enum ctattr_type {
CTA_ZONE, CTA_ZONE,
CTA_SECCTX, CTA_SECCTX,
CTA_TIMESTAMP, CTA_TIMESTAMP,
CTA_MARK_MASK,
__CTA_MAX __CTA_MAX
}; };
#define CTA_MAX (__CTA_MAX - 1) #define CTA_MAX (__CTA_MAX - 1)

35
net/netfilter/nf_conntrack_netlink.c
View File

@@ -691,9 +691,18 @@ static int ctnetlink_done(struct netlink_callback *cb)
{ {
if (cb->args[1]) if (cb->args[1])
nf_ct_put((struct nf_conn *)cb->args[1]); nf_ct_put((struct nf_conn *)cb->args[1]);
if (cb->data)
kfree(cb->data);
return 0; return 0;
} }
struct ctnetlink_dump_filter {
struct {
u_int32_t val;
u_int32_t mask;
} mark;
};
static int static int
ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb) ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
{ {
@@ -703,7 +712,9 @@ ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
struct hlist_nulls_node *n; struct hlist_nulls_node *n;
struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh); struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
u_int8_t l3proto = nfmsg->nfgen_family; u_int8_t l3proto = nfmsg->nfgen_family;
#ifdef CONFIG_NF_CONNTRACK_MARK
const struct ctnetlink_dump_filter *filter = cb->data;
#endif
spin_lock_bh(&nf_conntrack_lock); spin_lock_bh(&nf_conntrack_lock);
last = (struct nf_conn *)cb->args[1]; last = (struct nf_conn *)cb->args[1];
for (; cb->args[0] < net->ct.htable_size; cb->args[0]++) { for (; cb->args[0] < net->ct.htable_size; cb->args[0]++) {
@@ -723,6 +734,12 @@ restart:
continue; continue;
cb->args[1] = 0; cb->args[1] = 0;
} }
#ifdef CONFIG_NF_CONNTRACK_MARK
if (filter && !((ct->mark & filter->mark.mask) ==
filter->mark.val)) {
continue;
}
#endif
if (ctnetlink_fill_info(skb, NETLINK_CB(cb->skb).pid, if (ctnetlink_fill_info(skb, NETLINK_CB(cb->skb).pid,
cb->nlh->nlmsg_seq, cb->nlh->nlmsg_seq,
NFNL_MSG_TYPE( NFNL_MSG_TYPE(
@@ -894,6 +911,7 @@ static const struct nla_policy ct_nla_policy[CTA_MAX+1] = {
[CTA_NAT_DST] = { .type = NLA_NESTED }, [CTA_NAT_DST] = { .type = NLA_NESTED },
[CTA_TUPLE_MASTER] = { .type = NLA_NESTED }, [CTA_TUPLE_MASTER] = { .type = NLA_NESTED },
[CTA_ZONE] = { .type = NLA_U16 }, [CTA_ZONE] = { .type = NLA_U16 },
[CTA_MARK_MASK] = { .type = NLA_U32 },
}; };
static int static int
@@ -982,6 +1000,21 @@ ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb,
.dump = ctnetlink_dump_table, .dump = ctnetlink_dump_table,
.done = ctnetlink_done, .done = ctnetlink_done,
}; };
#ifdef CONFIG_NF_CONNTRACK_MARK
if (cda[CTA_MARK] && cda[CTA_MARK_MASK]) {
struct ctnetlink_dump_filter *filter;
filter = kzalloc(sizeof(struct ctnetlink_dump_filter),
GFP_ATOMIC);
if (filter == NULL)
return -ENOMEM;
filter->mark.val = ntohl(nla_get_be32(cda[CTA_MARK]));
filter->mark.mask =
ntohl(nla_get_be32(cda[CTA_MARK_MASK]));
c.data = filter;
}
#endif
return netlink_dump_start(ctnl, skb, nlh, &c); return netlink_dump_start(ctnl, skb, nlh, &c);
} }