[PATCH net-next 03/15] netfilter: flowtable: retrieve stats on flow deletion

[Pablo Neira Ayuso <pablo@netfilter.org>]

Retrieve stats too when deleting a flow from hardware. Apparently, the
existing approach is missing last stats sync with the conntrack entry.
Pass the stats object to the driver so it has a chance to populate it
at deletion time. Drivers need to be updated to use this new approach.

Reported-by: Valentin Berezhnoy <dreyksmail@gmail.com>
Closes: https://patch.msgid.link/netfilter-devel/20261021175030.4800-1-dreyksmail@gmail.com/
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_offload.c | 54 ++++++++++++++++-----------
 1 file changed, 33 insertions(+), 21 deletions(-)

diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c
index 3a18fa48cadb..c302051489f2 100644
--- a/net/netfilter/nf_flow_table_offload.c
+++ b/net/netfilter/nf_flow_table_offload.c
@@ -928,12 +928,33 @@ static int nf_flow_offload_tuple(struct nf_flowtable *flowtable,
 	}
 	up_read(&flowtable->flow_block_lock);
 
-	if (cmd == FLOW_CLS_STATS)
+	if (stats)
 		memcpy(stats, &cls_flow.stats, sizeof(*stats));
 
 	return i;
 }
 
+static void flow_offload_update_stats(struct flow_offload_work *offload,
+				      struct flow_stats *stats)
+{
+	u64 lastused;
+
+	lastused = max_t(u64, stats[0].lastused, stats[1].lastused);
+	offload->flow->timeout = max_t(u64, offload->flow->timeout,
+				       lastused + flow_offload_get_timeout(offload->flow));
+
+	if (offload->flowtable->flags & NF_FLOWTABLE_COUNTER) {
+		if (stats[0].pkts)
+			nf_ct_acct_add(offload->flow->ct,
+				       FLOW_OFFLOAD_DIR_ORIGINAL,
+				       stats[0].pkts, stats[0].bytes);
+		if (stats[1].pkts)
+			nf_ct_acct_add(offload->flow->ct,
+				       FLOW_OFFLOAD_DIR_REPLY,
+				       stats[1].pkts, stats[1].bytes);
+	}
+}
+
 static int flow_offload_tuple_add(struct flow_offload_work *offload,
 				  struct nf_flow_rule *flow_rule,
 				  enum flow_offload_tuple_dir dir)
@@ -946,11 +967,12 @@ static int flow_offload_tuple_add(struct flow_offload_work *offload,
 }
 
 static void flow_offload_tuple_del(struct flow_offload_work *offload,
-				   enum flow_offload_tuple_dir dir)
+				   enum flow_offload_tuple_dir dir,
+				   struct flow_stats *stats)
 {
 	nf_flow_offload_tuple(offload->flowtable, offload->flow, NULL, dir,
 			      offload->flowtable->priority,
-			      FLOW_CLS_DESTROY, NULL,
+			      FLOW_CLS_DESTROY, stats,
 			      &offload->flowtable->flow_block.cb_list);
 }
 
@@ -991,10 +1013,15 @@ static void flow_offload_work_add(struct flow_offload_work *offload)
 
 static void flow_offload_work_del(struct flow_offload_work *offload)
 {
+	struct flow_stats stats[FLOW_OFFLOAD_DIR_MAX] = {};
+
 	clear_bit(IPS_HW_OFFLOAD_BIT, &offload->flow->ct->status);
-	flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_ORIGINAL);
+	flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_ORIGINAL, &stats[0]);
 	if (test_bit(NF_FLOW_HW_BIDIRECTIONAL, &offload->flow->flags))
-		flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_REPLY);
+		flow_offload_tuple_del(offload, FLOW_OFFLOAD_DIR_REPLY, &stats[1]);
+
+	flow_offload_update_stats(offload, stats);
+
 	set_bit(NF_FLOW_HW_DEAD, &offload->flow->flags);
 }
 
@@ -1011,27 +1038,12 @@ static void flow_offload_tuple_stats(struct flow_offload_work *offload,
 static void flow_offload_work_stats(struct flow_offload_work *offload)
 {
 	struct flow_stats stats[FLOW_OFFLOAD_DIR_MAX] = {};
-	u64 lastused;
 
 	flow_offload_tuple_stats(offload, FLOW_OFFLOAD_DIR_ORIGINAL, &stats[0]);
 	if (test_bit(NF_FLOW_HW_BIDIRECTIONAL, &offload->flow->flags))
 		flow_offload_tuple_stats(offload, FLOW_OFFLOAD_DIR_REPLY,
 					 &stats[1]);
-
-	lastused = max_t(u64, stats[0].lastused, stats[1].lastused);
-	offload->flow->timeout = max_t(u64, offload->flow->timeout,
-				       lastused + flow_offload_get_timeout(offload->flow));
-
-	if (offload->flowtable->flags & NF_FLOWTABLE_COUNTER) {
-		if (stats[0].pkts)
-			nf_ct_acct_add(offload->flow->ct,
-				       FLOW_OFFLOAD_DIR_ORIGINAL,
-				       stats[0].pkts, stats[0].bytes);
-		if (stats[1].pkts)
-			nf_ct_acct_add(offload->flow->ct,
-				       FLOW_OFFLOAD_DIR_REPLY,
-				       stats[1].pkts, stats[1].bytes);
-	}
+	flow_offload_update_stats(offload, stats);
 }
 
 static void flow_offload_work_handler(struct work_struct *work)
-- 
2.47.3