netfilter: nf_tables: use new transaction infrastructure to handle sets

This patch reworks the nf_tables API so set updates are included in
the same batch that contains rule updates. This speeds up rule-set
updates since we skip a dialog of four messages between kernel and
user-space (two on each direction), from:

 1) create the set and send netlink message to the kernel
 2) process the response from the kernel that contains the allocated name.
 3) add the set elements and send netlink message to the kernel.
 4) process the response from the kernel (to check for errors).

To:

 1) add the set to the batch.
 2) add the set elements to the batch.
 3) add the rule that points to the set.
 4) send batch to the kernel.

This also introduces an internal set ID (NFTA_SET_ID) that is unique
in the batch so set elements and rules can refer to new sets.

Backward compatibility has been only retained in userspace, this
means that new nft versions can talk to the kernel both in the new
and the old fashion.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 18 insertions, 0 deletions

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index d8dfb2695e0f..0f472d668cbe 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -268,6 +268,8 @@ static inline void *nft_set_priv(const struct nft_set *set)
 
 struct nft_set *nf_tables_set_lookup(const struct nft_table *table,
 				     const struct nlattr *nla);
+struct nft_set *nf_tables_set_lookup_byid(const struct net *net,
+					  const struct nlattr *nla);
 
 /**
  *	struct nft_set_binding - nf_tables set binding
@@ -408,6 +410,16 @@ struct nft_trans_rule {
 #define nft_trans_rule(trans)	\
 	(((struct nft_trans_rule *)trans->data)->rule)
 
+struct nft_trans_set {
+	struct nft_set	*set;
+	u32		set_id;
+};
+
+#define nft_trans_set(trans)	\
+	(((struct nft_trans_set *)trans->data)->set)
+#define nft_trans_set_id(trans)	\
+	(((struct nft_trans_set *)trans->data)->set_id)
+
 static inline struct nft_expr *nft_expr_first(const struct nft_rule *rule)
 {
 	return (struct nft_expr *)&rule->data[0];
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 7d6433f66bf8..2a88f645a5d8 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -246,6 +246,7 @@ enum nft_set_desc_attributes {
  * @NFTA_SET_DATA_LEN: mapping data length (NLA_U32)
  * @NFTA_SET_POLICY: selection policy (NLA_U32)
  * @NFTA_SET_DESC: set description (NLA_NESTED)
+ * @NFTA_SET_ID: uniquely identifies a set in a transaction (NLA_U32)
  */
 enum nft_set_attributes {
 	NFTA_SET_UNSPEC,
@@ -258,6 +259,7 @@ enum nft_set_attributes {
 	NFTA_SET_DATA_LEN,
 	NFTA_SET_POLICY,
 	NFTA_SET_DESC,
+	NFTA_SET_ID,
 	__NFTA_SET_MAX
 };
 #define NFTA_SET_MAX		(__NFTA_SET_MAX - 1)
@@ -293,12 +295,14 @@ enum nft_set_elem_attributes {
  * @NFTA_SET_ELEM_LIST_TABLE: table of the set to be changed (NLA_STRING)
  * @NFTA_SET_ELEM_LIST_SET: name of the set to be changed (NLA_STRING)
  * @NFTA_SET_ELEM_LIST_ELEMENTS: list of set elements (NLA_NESTED: nft_set_elem_attributes)
+ * @NFTA_SET_ELEM_LIST_SET_ID: uniquely identifies a set in a transaction (NLA_U32)
  */
 enum nft_set_elem_list_attributes {
 	NFTA_SET_ELEM_LIST_UNSPEC,
 	NFTA_SET_ELEM_LIST_TABLE,
 	NFTA_SET_ELEM_LIST_SET,
 	NFTA_SET_ELEM_LIST_ELEMENTS,
+	NFTA_SET_ELEM_LIST_SET_ID,
 	__NFTA_SET_ELEM_LIST_MAX
 };
 #define NFTA_SET_ELEM_LIST_MAX	(__NFTA_SET_ELEM_LIST_MAX - 1)
@@ -484,12 +488,14 @@ enum nft_cmp_attributes {
  * @NFTA_LOOKUP_SET: name of the set where to look for (NLA_STRING)
  * @NFTA_LOOKUP_SREG: source register of the data to look for (NLA_U32: nft_registers)
  * @NFTA_LOOKUP_DREG: destination register (NLA_U32: nft_registers)
+ * @NFTA_LOOKUP_SET_ID: uniquely identifies a set in a transaction (NLA_U32)
  */
 enum nft_lookup_attributes {
 	NFTA_LOOKUP_UNSPEC,
 	NFTA_LOOKUP_SET,
 	NFTA_LOOKUP_SREG,
 	NFTA_LOOKUP_DREG,
+	NFTA_LOOKUP_SET_ID,
 	__NFTA_LOOKUP_MAX
 };
 #define NFTA_LOOKUP_MAX		(__NFTA_LOOKUP_MAX - 1)