netfilter: nftables: counter hardware offload support

This patch adds the .offload_stats operation to synchronize hardware
stats with the expression data. Update the counter expression to use
this new interface. The hardware stats are retrieved from the netlink
dump path via FLOW_CLS_STATS command to the driver.

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

1 files changed, 37 insertions, 7 deletions

diff --git a/net/netfilter/nf_tables_offload.c b/net/netfilter/nf_tables_offload.c
index 1d428792018f..19215e81dd66 100644
--- a/net/netfilter/nf_tables_offload.c
+++ b/net/netfilter/nf_tables_offload.c
@@ -243,26 +243,56 @@ static void nft_flow_cls_offload_setup(struct flow_cls_offload *cls_flow,
 		cls_flow->rule = flow->rule;
 }
 
-static int nft_flow_offload_rule(struct nft_chain *chain,
-				 struct nft_rule *rule,
-				 struct nft_flow_rule *flow,
-				 enum flow_cls_command command)
+static int nft_flow_offload_cmd(const struct nft_chain *chain,
+				const struct nft_rule *rule,
+				struct nft_flow_rule *flow,
+				enum flow_cls_command command,
+				struct flow_cls_offload *cls_flow)
 {
 	struct netlink_ext_ack extack = {};
-	struct flow_cls_offload cls_flow;
 	struct nft_base_chain *basechain;
 
 	if (!nft_is_base_chain(chain))
 		return -EOPNOTSUPP;
 
 	basechain = nft_base_chain(chain);
-	nft_flow_cls_offload_setup(&cls_flow, basechain, rule, flow, &extack,
+	nft_flow_cls_offload_setup(cls_flow, basechain, rule, flow, &extack,
 				   command);
 
-	return nft_setup_cb_call(TC_SETUP_CLSFLOWER, &cls_flow,
+	return nft_setup_cb_call(TC_SETUP_CLSFLOWER, cls_flow,
 				 &basechain->flow_block.cb_list);
 }
 
+static int nft_flow_offload_rule(const struct nft_chain *chain,
+				 struct nft_rule *rule,
+				 struct nft_flow_rule *flow,
+				 enum flow_cls_command command)
+{
+	struct flow_cls_offload cls_flow;
+
+	return nft_flow_offload_cmd(chain, rule, flow, command, &cls_flow);
+}
+
+int nft_flow_rule_stats(const struct nft_chain *chain,
+			const struct nft_rule *rule)
+{
+	struct flow_cls_offload cls_flow = {};
+	struct nft_expr *expr, *next;
+	int err;
+
+	err = nft_flow_offload_cmd(chain, rule, NULL, FLOW_CLS_STATS,
+				   &cls_flow);
+	if (err < 0)
+		return err;
+
+	nft_rule_for_each_expr(expr, next, rule) {
+		if (expr->ops->offload_stats)
+			expr->ops->offload_stats(expr, &cls_flow.stats);
+	}
+
+	return 0;
+}
+
 static int nft_flow_offload_bind(struct flow_block_offload *bo,
 				 struct nft_base_chain *basechain)
 {