netfilter: nf_tables: add hardware offload support

This patch adds hardware offload support for nftables through the
existing netdev_ops->ndo_setup_tc() interface, the TC_SETUP_CLSFLOWER
classifier and the flow rule API. This hardware offload support is
available for the NFPROTO_NETDEV family and the ingress hook.

Each nftables expression has a new ->offload interface, that is used to
populate the flow rule object that is attached to the transaction
object.

There is a new per-table NFT_TABLE_F_HW flag, that is set on to offload
an entire table, including all of its chains.

This patch supports for basic metadata (layer 3 and 4 protocol numbers),
5-tuple payload matching and the accept/drop actions; this also includes
basechain hardware offload only.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 0 deletions

diff --git a/net/netfilter/nft_immediate.c b/net/netfilter/nft_immediate.c
index cb8547f97220..ca2ae4b95a8d 100644
--- a/net/netfilter/nft_immediate.c
+++ b/net/netfilter/nft_immediate.c
@@ -13,6 +13,7 @@
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables_core.h>
 #include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_offload.h>
 
 void nft_immediate_eval(const struct nft_expr *expr,
 			struct nft_regs *regs,
@@ -124,6 +125,34 @@ static int nft_immediate_validate(const struct nft_ctx *ctx,
 	return 0;
 }
 
+static int nft_immediate_offload(struct nft_offload_ctx *ctx,
+				 struct nft_flow_rule *flow,
+				 const struct nft_expr *expr)
+{
+	const struct nft_immediate_expr *priv = nft_expr_priv(expr);
+	struct flow_action_entry *entry;
+	const struct nft_data *data;
+
+	if (priv->dreg != NFT_REG_VERDICT)
+		return -EOPNOTSUPP;
+
+	entry = &flow->rule->action.entries[ctx->num_actions++];
+
+	data = &priv->data;
+	switch (data->verdict.code) {
+	case NF_ACCEPT:
+		entry->id = FLOW_ACTION_ACCEPT;
+		break;
+	case NF_DROP:
+		entry->id = FLOW_ACTION_DROP;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
 static const struct nft_expr_ops nft_imm_ops = {
 	.type		= &nft_imm_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_immediate_expr)),
@@ -133,6 +162,8 @@ static const struct nft_expr_ops nft_imm_ops = {
 	.deactivate	= nft_immediate_deactivate,
 	.dump		= nft_immediate_dump,
 	.validate	= nft_immediate_validate,
+	.offload	= nft_immediate_offload,
+	.offload_flags	= NFT_OFFLOAD_F_ACTION,
 };
 
 struct nft_expr_type nft_imm_type __read_mostly = {