Re: [PATCH] netfilter: nf_flow_table: count offloaded flows

[Julian Anastasov <ja@xxxxxx>]

	Hello,

On Sun, 26 Feb 2023, Sven Auhagen wrote:

> Add a counter per namespace so we know the total offloaded
> flows.
> 
> 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..235847a9b480 100644
> --- a/include/net/netns/flow_table.h
> +++ b/include/net/netns/flow_table.h
> @@ -10,5 +10,6 @@ struct nf_flow_table_stat {
>  
>  struct netns_ft {
>  	struct nf_flow_table_stat __percpu *stat;
> +	atomic64_t count_flowoffload;
>  };
>  #endif
> diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
> index 81c26a96c30b..907307a44177 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);
> +	atomic64_inc(&net->ft.count_flowoffload);
> +
>  	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);
> +
> +	atomic64_dec(&net->ft.count_flowoffload);
>  }
>  
>  void flow_offload_teardown(struct flow_offload *flow)
> @@ -617,6 +625,7 @@ EXPORT_SYMBOL_GPL(nf_flow_table_free);
>  static int nf_flow_table_init_net(struct net *net)
>  {
>  	net->ft.stat = alloc_percpu(struct nf_flow_table_stat);
> +	atomic64_set(&net->ft.count_flowoffload, 0);
>  	return net->ft.stat ? 0 : -ENOMEM;
>  }
>  
> diff --git a/net/netfilter/nf_flow_table_procfs.c b/net/netfilter/nf_flow_table_procfs.c
> index 159b033a43e6..cff9ad58c7c9 100644
> --- a/net/netfilter/nf_flow_table_procfs.c
> +++ b/net/netfilter/nf_flow_table_procfs.c
> @@ -64,6 +64,16 @@ 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_net(seq);
> +
> +	seq_printf(seq, "%lld\n",
> +		   atomic64_read(&net->ft.count_flowoffload)
> +		);
> +	return 0;
> +}
> +
>  int nf_flow_table_init_proc(struct net *net)
>  {
>  	struct proc_dir_entry *pde;
> @@ -71,6 +81,9 @@ int nf_flow_table_init_proc(struct net *net)
>  	pde = proc_create_net("nf_flowtable", 0444, net->proc_net_stat,
>  			      &nf_flow_table_cpu_seq_ops,
>  			      sizeof(struct seq_net_private));

	Result should be checked, pde is not needed:

	if (!proc_create_net())
		goto err;

> +	proc_create_net_single("nf_flowtable_counter", 0444,
> +			net->proc_net, nf_flow_table_counter_show, NULL);

	if (!proc_create_net_single())
		goto err_net;
	return 0;

err_net:
	remove_proc_entry("nf_flowtable", net->proc_net_stat);

err:
	return -ENOMEM;

> +
>  	return pde ? 0 : -ENOMEM;
>  }
>  
> -- 
> 2.33.1

Regards

--
Julian Anastasov <ja@xxxxxx>