netfilter: ctnetlink: add callbacks to the per-proto nlattrs

There is added a single callback for the l3 proto helper.  The two
callbacks for the l4 protos are necessary because of the general
structure of a ctnetlink event, which is in short:

 CTA_TUPLE_ORIG
   <l3/l4-proto-attributes>
 CTA_TUPLE_REPLY
   <l3/l4-proto-attributes>
 CTA_ID
 ...
 CTA_PROTOINFO
   <l4-proto-attributes>
 CTA_TUPLE_MASTER
   <l3/l4-proto-attributes>

Therefore the formular is

 size := sizeof(generic-nlas) + 3 * sizeof(tuple_nlas) + sizeof(protoinfo_nlas)

Some of the NLAs are optional, e. g. CTA_TUPLE_MASTER, which is only
set if it's an expected connection.  But the number of optional NLAs is
small enough to prevent netlink_trim() from reallocating if calculated
properly.

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 16 insertions, 0 deletions

diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c
index 9a62b4efa0e1..1a4568bf7ea5 100644
--- a/net/netfilter/nf_conntrack_proto.c
+++ b/net/netfilter/nf_conntrack_proto.c
@@ -167,6 +167,9 @@ int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
         if (proto->l3proto >= AF_MAX)
                 return -EBUSY;
 
+        if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size)
+                return -EINVAL;
+
         mutex_lock(&nf_ct_proto_mutex);
         if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
                 ret = -EBUSY;
@@ -177,6 +180,9 @@ int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
         if (ret < 0)
                 goto out_unlock;
 
+        if (proto->nlattr_tuple_size)
+                proto->nla_size = 3 * proto->nlattr_tuple_size();
+
         rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
 
 out_unlock:
@@ -263,6 +269,10 @@ int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
         if (l4proto->l3proto >= PF_MAX)
                 return -EBUSY;
 
+        if ((l4proto->to_nlattr && !l4proto->nlattr_size)
+                || (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size))
+                return -EINVAL;
+
         mutex_lock(&nf_ct_proto_mutex);
         if (!nf_ct_protos[l4proto->l3proto]) {
                 /* l3proto may be loaded latter. */
@@ -290,6 +300,12 @@ int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
         if (ret < 0)
                 goto out_unlock;
 
+        l4proto->nla_size = 0;
+        if (l4proto->nlattr_size)
+                l4proto->nla_size += l4proto->nlattr_size();
+        if (l4proto->nlattr_tuple_size)
+                l4proto->nla_size += 3 * l4proto->nlattr_tuple_size();
+
         rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
                            l4proto);