netfilter: nf_conntrack: add efficient mark to zone mapping

This work adds the possibility of deriving the zone id from the skb->mark
field in a scalable manner. This allows for having only a single template
serving hundreds/thousands of different zones, for example, instead of the
need to have one match for each zone as an extra CT jump target.

Note that we'd need to have this information attached to the template as at
the time when we're trying to lookup a possible ct object, we already need
to know zone information for a possible match when going into
__nf_conntrack_find_get(). This work provides a minimal implementation for
a possible mapping.

In order to not add/expose an extra ct->status bit, the zone structure has
been extended to carry a flag for deriving the mark.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/net/netfilter/nf_conntrack_zones.h b/include/net/netfilter/nf_conntrack_zones.h
index 3942ddf0d4ff3382beae83ed721ad7df1646e77a..5316c7b3a374db1aa0b724e4a133a8f656bbb8da 100644 (file)
--- a/include/net/netfilter/nf_conntrack_zones.h
+++ b/include/net/netfilter/nf_conntrack_zones.h
@@ -10,9 +10,12 @@
 
 #define NF_CT_DEFAULT_ZONE_DIR (NF_CT_ZONE_DIR_ORIG | NF_CT_ZONE_DIR_REPL)
 
+#define NF_CT_FLAG_MARK                1
+
 struct nf_conntrack_zone {
        u16     id;
-       u16     dir;
+       u8      flags;
+       u8      dir;
 };
 
 extern const struct nf_conntrack_zone nf_ct_zone_dflt;
@@ -32,9 +35,45 @@ nf_ct_zone(const struct nf_conn *ct)
 }
 
 static inline const struct nf_conntrack_zone *
-nf_ct_zone_tmpl(const struct nf_conn *tmpl)
+nf_ct_zone_init(struct nf_conntrack_zone *zone, u16 id, u8 dir, u8 flags)
+{
+       zone->id = id;
+       zone->flags = flags;
+       zone->dir = dir;
+
+       return zone;
+}
+
+static inline const struct nf_conntrack_zone *
+nf_ct_zone_tmpl(const struct nf_conn *tmpl, const struct sk_buff *skb,
+               struct nf_conntrack_zone *tmp)
+{
+       const struct nf_conntrack_zone *zone;
+
+       if (!tmpl)
+               return &nf_ct_zone_dflt;
+
+       zone = nf_ct_zone(tmpl);
+       if (zone->flags & NF_CT_FLAG_MARK)
+               zone = nf_ct_zone_init(tmp, skb->mark, zone->dir, 0);
+
+       return zone;
+}
+
+static inline int nf_ct_zone_add(struct nf_conn *ct, gfp_t flags,
+                                const struct nf_conntrack_zone *info)
 {
-       return tmpl ? nf_ct_zone(tmpl) : &nf_ct_zone_dflt;
+#ifdef CONFIG_NF_CONNTRACK_ZONES
+       struct nf_conntrack_zone *nf_ct_zone;
+
+       nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, flags);
+       if (!nf_ct_zone)
+               return -ENOMEM;
+
+       nf_ct_zone_init(nf_ct_zone, info->id, info->dir,
+                       info->flags);
+#endif
+       return 0;
 }
 
 static inline bool nf_ct_zone_matches_dir(const struct nf_conntrack_zone *zone,

diff --git a/include/uapi/linux/netfilter/xt_CT.h b/include/uapi/linux/netfilter/xt_CT.h
index 452005ff0e9e4ab659f01a1e88218678b63bb9b3..9e520418b858d5f5a355ee8514f5f1d3ee4a827f 100644 (file)
--- a/include/uapi/linux/netfilter/xt_CT.h
+++ b/include/uapi/linux/netfilter/xt_CT.h
@@ -8,9 +8,11 @@ enum {
        XT_CT_NOTRACK_ALIAS     = 1 << 1,
        XT_CT_ZONE_DIR_ORIG     = 1 << 2,
        XT_CT_ZONE_DIR_REPL     = 1 << 3,
+       XT_CT_ZONE_MARK         = 1 << 4,
 
        XT_CT_MASK              = XT_CT_NOTRACK | XT_CT_NOTRACK_ALIAS |
-                                 XT_CT_ZONE_DIR_ORIG | XT_CT_ZONE_DIR_REPL,
+                                 XT_CT_ZONE_DIR_ORIG | XT_CT_ZONE_DIR_REPL |
+                                 XT_CT_ZONE_MARK,
 };
 
 struct xt_ct_target_info {

diff --cc net/ipv4/netfilter/nf_conntrack_proto_icmp.c
Simple merge

diff --cc net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c
Simple merge

diff --cc net/netfilter/nf_conntrack_core.c
Simple merge

diff --cc net/netfilter/nf_conntrack_netlink.c
Simple merge

diff --cc net/netfilter/xt_CT.c
Simple merge