By default the kernel emits all ctnetlink events for a connection.
This allows to select the types of events to generate.
This can be used to e.g. only send DESTROY events but no NEW/UPDATE ones
and will work even if sysctl net.netfilter.nf_conntrack_events is set to 0.
This was already possible via iptables' CT target, but the nft version has
the advantage that it can also be used with already-established conntracks.
The added nf_ct_is_template() check isn't a bug fix as we only support
mark and labels (and unlike ecache the conntrack core doesn't copy those).
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
Changes since v2:
- use u32 ctmask and load register directly, pointed
out by Liping. nft userspace populates an u32 register
with a hostendian mask, so nft_reg_load16() is wrong.
Changes since v1:
- use nft_reg_load16() helper
- add extension if its not there and ct isn't confirmed yet.
include/uapi/linux/netfilter/nf_tables.h | 2 ++
net/netfilter/nft_ct.c | 25 ++++++++++++++++++++++++-
2 files changed, 26 insertions(+), 1 deletion(-)
NFT_CT_EXPMASK is still missing, adding it should be very simple, its
essentially copy&paste of this and the two ctevent userspace patches
(nft/libnftnl).
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 8f3842690d17..683f6f88fcac 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -901,6 +901,7 @@ enum nft_rt_attributes {
* @NFT_CT_BYTES: conntrack bytes
* @NFT_CT_AVGPKT: conntrack average bytes per packet
* @NFT_CT_ZONE: conntrack zone
+ * @NFT_CT_EVENTMASK: ctnetlink events to be generated for this conntrack
*/
enum nft_ct_keys {
NFT_CT_STATE,
@@ -921,6 +922,7 @@ enum nft_ct_keys {
NFT_CT_BYTES,
NFT_CT_AVGPKT,
NFT_CT_ZONE,
+ NFT_CT_EVENTMASK,
};
/**
diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 6c6fd48b024c..a34ceb38fc55 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -264,7 +264,7 @@ static void nft_ct_set_eval(const struct nft_expr *expr,
struct nf_conn *ct;
ct = nf_ct_get(skb, &ctinfo);
- if (ct == NULL)
+ if (ct == NULL || nf_ct_is_template(ct))
return;
switch (priv->key) {
@@ -284,6 +284,22 @@ static void nft_ct_set_eval(const struct nft_expr *expr,
NF_CT_LABELS_MAX_SIZE / sizeof(u32));
break;
#endif
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+ case NFT_CT_EVENTMASK: {
+ struct nf_conntrack_ecache *e = nf_ct_ecache_find(ct);
+ u32 ctmask = regs->data[priv->sreg];
+
+ if (e) {
+ if (e->ctmask != ctmask)
+ e->ctmask = ctmask;
+ break;
+ }
+
+ if (ctmask && !nf_ct_is_confirmed(ct))
+ nf_ct_ecache_ext_add(ct, ctmask, 0, GFP_ATOMIC);
+ break;
+ }
+#endif
default:
break;
}
@@ -539,6 +555,13 @@ static int nft_ct_set_init(const struct nft_ctx *ctx,
len = sizeof(u16);
break;
#endif
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+ case NFT_CT_EVENTMASK:
+ if (tb[NFTA_CT_DIRECTION])
+ return -EINVAL;
+ len = sizeof(u32);
+ break;
+#endif
default:
return -EOPNOTSUPP;
}
--
2.10.2
--
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