netfilter: add connlabel conntrack extension

similar to connmarks, except labels are bit-based; i.e.
all labels may be attached to a flow at the same time.

Up to 128 labels are supported.  Supporting more labels
is possible, but requires increasing the ct offset delta
from u8 to u16 type due to increased extension sizes.

Mapping of bit-identifier to label name is done in userspace.

The extension is enabled at run-time once "-m connlabel" netfilter
rules are added.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/net/netns/conntrack.h b/include/net/netns/conntrack.h
index 923cb20051ed..c9c0c538b68b 100644
--- a/include/net/netns/conntrack.h
+++ b/include/net/netns/conntrack.h
@@ -84,6 +84,10 @@ struct netns_ct {
         int                     sysctl_auto_assign_helper;
         bool                    auto_assign_helper_warned;
         struct nf_ip_net        nf_ct_proto;
+#if defined(CONFIG_NF_CONNTRACK_LABELS)
+        unsigned int            labels_used;
+        u8                      label_words;
+#endif
 #ifdef CONFIG_NF_NAT_NEEDED
         struct hlist_head       *nat_bysource;
         unsigned int            nat_htable_size;