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@xxxxxxxxxxxxxxxx>
Index: net-next-2.6/include/net/netfilter/nf_conntrack_l3proto.h
===================================================================
--- net-next-2.6.orig/include/net/netfilter/nf_conntrack_l3proto.h
+++ net-next-2.6/include/net/netfilter/nf_conntrack_l3proto.h
@@ -53,10 +53,17 @@ struct nf_conntrack_l3proto
int (*tuple_to_nlattr)(struct sk_buff *skb,
const struct nf_conntrack_tuple *t);
+ /*
+ * Calculate size of tuple nlattr
+ */
+ int (*nlattr_tuple_size)(void);
+
int (*nlattr_to_tuple)(struct nlattr *tb[],
struct nf_conntrack_tuple *t);
const struct nla_policy *nla_policy;
+ size_t nla_size;
+
#ifdef CONFIG_SYSCTL
struct ctl_table_header *ctl_table_header;
struct ctl_path *ctl_table_path;
Index: net-next-2.6/include/net/netfilter/nf_conntrack_l4proto.h
===================================================================
--- net-next-2.6.orig/include/net/netfilter/nf_conntrack_l4proto.h
+++ net-next-2.6/include/net/netfilter/nf_conntrack_l4proto.h
@@ -64,16 +64,22 @@ struct nf_conntrack_l4proto
/* convert protoinfo to nfnetink attributes */
int (*to_nlattr)(struct sk_buff *skb, struct nlattr *nla,
const struct nf_conn *ct);
+ /* Calculate protoinfo nlattr size */
+ int (*nlattr_size)(void);
/* convert nfnetlink attributes to protoinfo */
int (*from_nlattr)(struct nlattr *tb[], struct nf_conn *ct);
int (*tuple_to_nlattr)(struct sk_buff *skb,
const struct nf_conntrack_tuple *t);
+ /* Calculate tuple nlattr size */
+ int (*nlattr_tuple_size)(void);
int (*nlattr_to_tuple)(struct nlattr *tb[],
struct nf_conntrack_tuple *t);
const struct nla_policy *nla_policy;
+ size_t nla_size;
+
#ifdef CONFIG_SYSCTL
struct ctl_table_header **ctl_table_header;
struct ctl_table *ctl_table;
Index: net-next-2.6/net/netfilter/nf_conntrack_proto.c
===================================================================
--- net-next-2.6.orig/net/netfilter/nf_conntrack_proto.c
+++ net-next-2.6/net/netfilter/nf_conntrack_proto.c
@@ -188,6 +188,9 @@ int nf_conntrack_l3proto_register(struct
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;
@@ -198,6 +201,9 @@ int nf_conntrack_l3proto_register(struct
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:
@@ -284,6 +290,10 @@ int nf_conntrack_l4proto_register(struct
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. */
@@ -311,6 +321,12 @@ int nf_conntrack_l4proto_register(struct
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);
--
--
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