[PATCH v5] netfilter: nf_flow_table: count offloaded flows

[Sven Auhagen <Sven.Auhagen@xxxxxxxxxxxx>]

Add a counter per namespace so we know the total offloaded
flows.

Change from v4:
	* use per cpu counters instead of an atomic variable

Change from v3:
	* seq_file_net has to be seq_file_single_net

Change from v2:
	* Add remove proc entry on nf_flow_table_fini_proc
	* Syntax fixes

Change from v1:
	* Cleanup proc entries in case of an error

Signed-off-by: Abdelrahman Morsy <abdelrahman.morsy@xxxxxxxxxxxx>
Signed-off-by: Sven Auhagen <sven.auhagen@xxxxxxxxxxxx>

diff --git a/include/net/netns/flow_table.h b/include/net/netns/flow_table.h
index 1c5fc657e267..1496a6af6ac4 100644
--- a/include/net/netns/flow_table.h
+++ b/include/net/netns/flow_table.h
@@ -6,6 +6,8 @@ struct nf_flow_table_stat {
 	unsigned int count_wq_add;
 	unsigned int count_wq_del;
 	unsigned int count_wq_stats;
+	unsigned int count_flowoffload_add;
+	unsigned int count_flowoffload_del;
 };
 
 struct netns_ft {
diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
index 81c26a96c30b..d6bc8f0ff51d 100644
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -282,6 +282,7 @@ unsigned long flow_offload_get_timeout(struct flow_offload *flow)
 
 int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
 {
+	struct net *net;
 	int err;
 
 	flow->timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow);
@@ -304,6 +305,9 @@ int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
 
 	nf_ct_offload_timeout(flow->ct);
 
+	net = read_pnet(&flow_table->net);
+	NF_FLOW_TABLE_STAT_INC_ATOMIC(net, count_flowoffload_add);
+
 	if (nf_flowtable_hw_offload(flow_table)) {
 		__set_bit(NF_FLOW_HW, &flow->flags);
 		nf_flow_offload_add(flow_table, flow);
@@ -339,6 +343,8 @@ static inline bool nf_flow_has_expired(const struct flow_offload *flow)
 static void flow_offload_del(struct nf_flowtable *flow_table,
 			     struct flow_offload *flow)
 {
+	struct net *net = read_pnet(&flow_table->net);
+
 	rhashtable_remove_fast(&flow_table->rhashtable,
 			       &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
 			       nf_flow_offload_rhash_params);
@@ -346,6 +352,8 @@ static void flow_offload_del(struct nf_flowtable *flow_table,
 			       &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
 			       nf_flow_offload_rhash_params);
 	flow_offload_free(flow);
+
+	NF_FLOW_TABLE_STAT_INC_ATOMIC(net, count_flowoffload_del);
 }
 
 void flow_offload_teardown(struct flow_offload *flow)
diff --git a/net/netfilter/nf_flow_table_procfs.c b/net/netfilter/nf_flow_table_procfs.c
index 159b033a43e6..c4d15bd1a0f0 100644
--- a/net/netfilter/nf_flow_table_procfs.c
+++ b/net/netfilter/nf_flow_table_procfs.c
@@ -64,17 +64,49 @@ static const struct seq_operations nf_flow_table_cpu_seq_ops = {
 	.show	= nf_flow_table_cpu_seq_show,
 };
 
+static int nf_flow_table_counter_show(struct seq_file *seq, void *v)
+{
+	struct net *net = seq_file_single_net(seq);
+	struct nf_flow_table_stat *st;
+	unsigned int counter_add = 0;
+	unsigned int counter_del = 0;
+	int cpu;
+
+	for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
+		if (!cpu_possible(cpu))
+			continue;
+
+		st = per_cpu_ptr(net->ft.stat, cpu);
+		counter_add += st->count_flowoffload_add;
+		counter_del += st->count_flowoffload_del;
+	}
+
+	seq_printf(seq, "%d\n",
+		   (counter_add - counter_del)
+		);
+	return 0;
+}
+
 int nf_flow_table_init_proc(struct net *net)
 {
-	struct proc_dir_entry *pde;
+	if (!proc_create_net("nf_flowtable", 0444, net->proc_net_stat,
+			     &nf_flow_table_cpu_seq_ops, sizeof(struct seq_net_private)))
+		goto err;
 
-	pde = proc_create_net("nf_flowtable", 0444, net->proc_net_stat,
-			      &nf_flow_table_cpu_seq_ops,
-			      sizeof(struct seq_net_private));
-	return pde ? 0 : -ENOMEM;
+	if (!proc_create_net_single("nf_flowtable_counter", 0444,
+				    net->proc_net, nf_flow_table_counter_show, NULL))
+		goto err_net;
+
+	return 0;
+
+err_net:
+	remove_proc_entry("nf_flowtable", net->proc_net_stat);
+err:
+	return -ENOMEM;
 }
 
 void nf_flow_table_fini_proc(struct net *net)
 {
 	remove_proc_entry("nf_flowtable", net->proc_net_stat);
+	remove_proc_entry("nf_flowtable_counter", net->proc_net);
 }
-- 
2.33.1