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, 33 insertions, 6 deletions

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index d22d00ca78c1..ed17a7c29b86 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -18,6 +18,7 @@
 #include <net/netfilter/nf_flow_table.h>
 #include <net/netfilter/nf_tables_core.h>
 #include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_offload.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 
@@ -97,6 +98,7 @@ static void nft_ctx_init(struct nft_ctx *ctx,
 	ctx->nla   	= nla;
 	ctx->portid	= NETLINK_CB(skb).portid;
 	ctx->report	= nlmsg_report(nlh);
+	ctx->flags	= nlh->nlmsg_flags;
 	ctx->seq	= nlh->nlmsg_seq;
 }
 
@@ -1169,6 +1171,7 @@ static const struct nla_policy nft_chain_policy[NFTA_CHAIN_MAX + 1] = {
 	[NFTA_CHAIN_POLICY]	= { .type = NLA_U32 },
 	[NFTA_CHAIN_TYPE]	= { .type = NLA_STRING },
 	[NFTA_CHAIN_COUNTERS]	= { .type = NLA_NESTED },
+	[NFTA_CHAIN_FLAGS]	= { .type = NLA_U32 },
 };
 
 static const struct nla_policy nft_hook_policy[NFTA_HOOK_MAX + 1] = {
@@ -1603,7 +1606,7 @@ static struct nft_rule **nf_tables_chain_alloc_rules(const struct nft_chain *cha
 }
 
 static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
-			      u8 policy)
+			      u8 policy, u32 flags)
 {
 	const struct nlattr * const *nla = ctx->nla;
 	struct nft_table *table = ctx->table;
@@ -1657,8 +1660,9 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
 		ops->hook	= hook.type->hooks[ops->hooknum];
 		ops->dev	= hook.dev;
 
-		chain->flags |= NFT_BASE_CHAIN;
+		chain->flags |= NFT_BASE_CHAIN | flags;
 		basechain->policy = NF_ACCEPT;
+		INIT_LIST_HEAD(&basechain->cb_list);
 	} else {
 		chain = kzalloc(sizeof(*chain), GFP_KERNEL);
 		if (chain == NULL)
@@ -1718,7 +1722,8 @@ err1:
 	return err;
 }
 
-static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy)
+static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy,
+			      u32 flags)
 {
 	const struct nlattr * const *nla = ctx->nla;
 	struct nft_table *table = ctx->table;
@@ -1730,6 +1735,9 @@ static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy)
 	struct nft_trans *trans;
 	int err;
 
+	if (chain->flags ^ flags)
+		return -EOPNOTSUPP;
+
 	if (nla[NFTA_CHAIN_HOOK]) {
 		if (!nft_is_base_chain(chain))
 			return -EBUSY;
@@ -1835,6 +1843,7 @@ static int nf_tables_newchain(struct net *net, struct sock *nlsk,
 	u8 policy = NF_ACCEPT;
 	struct nft_ctx ctx;
 	u64 handle = 0;
+	u32 flags = 0;
 
 	lockdep_assert_held(&net->nft.commit_mutex);
 
@@ -1889,6 +1898,9 @@ static int nf_tables_newchain(struct net *net, struct sock *nlsk,
 		}
 	}
 
+	if (nla[NFTA_CHAIN_FLAGS])
+		flags = ntohl(nla_get_be32(nla[NFTA_CHAIN_FLAGS]));
+
 	nft_ctx_init(&ctx, net, skb, nlh, family, table, chain, nla);
 
 	if (chain != NULL) {
@@ -1899,10 +1911,10 @@ static int nf_tables_newchain(struct net *net, struct sock *nlsk,
 		if (nlh->nlmsg_flags & NLM_F_REPLACE)
 			return -EOPNOTSUPP;
 
-		return nf_tables_updchain(&ctx, genmask, policy);
+		return nf_tables_updchain(&ctx, genmask, policy, flags);
 	}
 
-	return nf_tables_addchain(&ctx, family, genmask, policy);
+	return nf_tables_addchain(&ctx, family, genmask, policy, flags);
 }
 
 static int nf_tables_delchain(struct net *net, struct sock *nlsk,
@@ -2658,6 +2670,7 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk,
 	u8 genmask = nft_genmask_next(net);
 	struct nft_expr_info *info = NULL;
 	int family = nfmsg->nfgen_family;
+	struct nft_flow_rule *flow;
 	struct nft_table *table;
 	struct nft_chain *chain;
 	struct nft_rule *rule, *old_rule = NULL;
@@ -2804,7 +2817,8 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk,
 
 		list_add_tail_rcu(&rule->list, &old_rule->list);
 	} else {
-		if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) {
+		trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule);
+		if (!trans) {
 			err = -ENOMEM;
 			goto err2;
 		}
@@ -2827,6 +2841,14 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk,
 	if (net->nft.validate_state == NFT_VALIDATE_DO)
 		return nft_table_validate(net, table);
 
+	if (chain->flags & NFT_CHAIN_HW_OFFLOAD) {
+		flow = nft_flow_rule_create(rule);
+		if (IS_ERR(flow))
+			return PTR_ERR(flow);
+
+		nft_trans_flow_rule(trans) = flow;
+	}
+
 	return 0;
 err2:
 	nf_tables_rule_release(&ctx, rule);
@@ -6624,6 +6646,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 	struct nft_trans_elem *te;
 	struct nft_chain *chain;
 	struct nft_table *table;
+	int err;
 
 	if (list_empty(&net->nft.commit_list)) {
 		mutex_unlock(&net->nft.commit_mutex);
@@ -6634,6 +6657,10 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 	if (nf_tables_validate(net) < 0)
 		return -EAGAIN;
 
+	err = nft_flow_rule_offload_commit(net);
+	if (err < 0)
+		return err;
+
 	/* 1.  Allocate space for next generation rules_gen_X[] */
 	list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
 		int ret;