From b72920f6e4a9d6607b723d69b7f412c829769c75 Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Thu, 15 Apr 2021 20:10:18 +0200
Subject: 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>
---
 net/netfilter/nft_counter.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

(limited to 'net/netfilter/nft_counter.c')

diff --git a/net/netfilter/nft_counter.c b/net/netfilter/nft_counter.c
index 85ed461ec24e..8edd3b3c173d 100644
--- a/net/netfilter/nft_counter.c
+++ b/net/netfilter/nft_counter.c
@@ -13,6 +13,7 @@
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_offload.h>
 
 struct nft_counter {
 	s64		bytes;
@@ -248,6 +249,32 @@ static int nft_counter_clone(struct nft_expr *dst, const struct nft_expr *src)
 	return 0;
 }
 
+static int nft_counter_offload(struct nft_offload_ctx *ctx,
+			       struct nft_flow_rule *flow,
+			       const struct nft_expr *expr)
+{
+	/* No specific offload action is needed, but report success. */
+	return 0;
+}
+
+static void nft_counter_offload_stats(struct nft_expr *expr,
+				      const struct flow_stats *stats)
+{
+	struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
+	struct nft_counter *this_cpu;
+	seqcount_t *myseq;
+
+	preempt_disable();
+	this_cpu = this_cpu_ptr(priv->counter);
+	myseq = this_cpu_ptr(&nft_counter_seq);
+
+	write_seqcount_begin(myseq);
+	this_cpu->packets += stats->pkts;
+	this_cpu->bytes += stats->bytes;
+	write_seqcount_end(myseq);
+	preempt_enable();
+}
+
 static struct nft_expr_type nft_counter_type;
 static const struct nft_expr_ops nft_counter_ops = {
 	.type		= &nft_counter_type,
@@ -258,6 +285,8 @@ static const struct nft_expr_ops nft_counter_ops = {
 	.destroy_clone	= nft_counter_destroy,
 	.dump		= nft_counter_dump,
 	.clone		= nft_counter_clone,
+	.offload	= nft_counter_offload,
+	.offload_stats	= nft_counter_offload_stats,
 };
 
 static struct nft_expr_type nft_counter_type __read_mostly = {
-- 
cgit