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  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
  4 *
  5 * Development of this code funded by Astaro AG (http://www.astaro.com/)
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/init.h>
 10#include <linux/module.h>
 11#include <linux/seqlock.h>
 12#include <linux/netlink.h>
 13#include <linux/netfilter.h>
 14#include <linux/netfilter/nf_tables.h>
 15#include <net/netfilter/nf_tables.h>
 16#include <net/netfilter/nf_tables_offload.h>
 17
 18struct nft_counter {
 19	s64		bytes;
 20	s64		packets;
 21};
 22
 23struct nft_counter_percpu_priv {
 24	struct nft_counter __percpu *counter;
 25};
 26
 27static DEFINE_PER_CPU(seqcount_t, nft_counter_seq);
 28
 29static inline void nft_counter_do_eval(struct nft_counter_percpu_priv *priv,
 30				       struct nft_regs *regs,
 31				       const struct nft_pktinfo *pkt)
 32{
 33	struct nft_counter *this_cpu;
 34	seqcount_t *myseq;
 35
 36	local_bh_disable();
 37	this_cpu = this_cpu_ptr(priv->counter);
 38	myseq = this_cpu_ptr(&nft_counter_seq);
 39
 40	write_seqcount_begin(myseq);
 41
 42	this_cpu->bytes += pkt->skb->len;
 43	this_cpu->packets++;
 44
 45	write_seqcount_end(myseq);
 46	local_bh_enable();
 47}
 48
 49static inline void nft_counter_obj_eval(struct nft_object *obj,
 50					struct nft_regs *regs,
 51					const struct nft_pktinfo *pkt)
 52{
 53	struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 54
 55	nft_counter_do_eval(priv, regs, pkt);
 56}
 57
 58static int nft_counter_do_init(const struct nlattr * const tb[],
 59			       struct nft_counter_percpu_priv *priv)
 60{
 61	struct nft_counter __percpu *cpu_stats;
 62	struct nft_counter *this_cpu;
 63
 64	cpu_stats = alloc_percpu(struct nft_counter);
 65	if (cpu_stats == NULL)
 66		return -ENOMEM;
 67
 68	preempt_disable();
 69	this_cpu = this_cpu_ptr(cpu_stats);
 70	if (tb[NFTA_COUNTER_PACKETS]) {
 71	        this_cpu->packets =
 72			be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_PACKETS]));
 73	}
 74	if (tb[NFTA_COUNTER_BYTES]) {
 75		this_cpu->bytes =
 76			be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_BYTES]));
 77	}
 78	preempt_enable();
 79	priv->counter = cpu_stats;
 80	return 0;
 81}
 82
 83static int nft_counter_obj_init(const struct nft_ctx *ctx,
 84				const struct nlattr * const tb[],
 85				struct nft_object *obj)
 86{
 87	struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 88
 89	return nft_counter_do_init(tb, priv);
 90}
 91
 92static void nft_counter_do_destroy(struct nft_counter_percpu_priv *priv)
 93{
 94	free_percpu(priv->counter);
 95}
 96
 97static void nft_counter_obj_destroy(const struct nft_ctx *ctx,
 98				    struct nft_object *obj)
 99{
100	struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
101
102	nft_counter_do_destroy(priv);
103}
104
105static void nft_counter_reset(struct nft_counter_percpu_priv *priv,
106			      struct nft_counter *total)
107{
108	struct nft_counter *this_cpu;
109
110	local_bh_disable();
111	this_cpu = this_cpu_ptr(priv->counter);
112	this_cpu->packets -= total->packets;
113	this_cpu->bytes -= total->bytes;
114	local_bh_enable();
115}
116
117static void nft_counter_fetch(struct nft_counter_percpu_priv *priv,
118			      struct nft_counter *total)
119{
120	struct nft_counter *this_cpu;
121	const seqcount_t *myseq;
122	u64 bytes, packets;
123	unsigned int seq;
124	int cpu;
125
126	memset(total, 0, sizeof(*total));
127	for_each_possible_cpu(cpu) {
128		myseq = per_cpu_ptr(&nft_counter_seq, cpu);
129		this_cpu = per_cpu_ptr(priv->counter, cpu);
130		do {
131			seq	= read_seqcount_begin(myseq);
132			bytes	= this_cpu->bytes;
133			packets	= this_cpu->packets;
134		} while (read_seqcount_retry(myseq, seq));
135
136		total->bytes	+= bytes;
137		total->packets	+= packets;
138	}
139}
140
141static int nft_counter_do_dump(struct sk_buff *skb,
142			       struct nft_counter_percpu_priv *priv,
143			       bool reset)
144{
145	struct nft_counter total;
146
147	nft_counter_fetch(priv, &total);
148
149	if (nla_put_be64(skb, NFTA_COUNTER_BYTES, cpu_to_be64(total.bytes),
150			 NFTA_COUNTER_PAD) ||
151	    nla_put_be64(skb, NFTA_COUNTER_PACKETS, cpu_to_be64(total.packets),
152			 NFTA_COUNTER_PAD))
153		goto nla_put_failure;
154
155	if (reset)
156		nft_counter_reset(priv, &total);
157
158	return 0;
159
160nla_put_failure:
161	return -1;
162}
163
164static int nft_counter_obj_dump(struct sk_buff *skb,
165				struct nft_object *obj, bool reset)
166{
167	struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
168
169	return nft_counter_do_dump(skb, priv, reset);
170}
171
172static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
173	[NFTA_COUNTER_PACKETS]	= { .type = NLA_U64 },
174	[NFTA_COUNTER_BYTES]	= { .type = NLA_U64 },
175};
176
177static struct nft_object_type nft_counter_obj_type;
178static const struct nft_object_ops nft_counter_obj_ops = {
179	.type		= &nft_counter_obj_type,
180	.size		= sizeof(struct nft_counter_percpu_priv),
181	.eval		= nft_counter_obj_eval,
182	.init		= nft_counter_obj_init,
183	.destroy	= nft_counter_obj_destroy,
184	.dump		= nft_counter_obj_dump,
185};
186
187static struct nft_object_type nft_counter_obj_type __read_mostly = {
188	.type		= NFT_OBJECT_COUNTER,
189	.ops		= &nft_counter_obj_ops,
190	.maxattr	= NFTA_COUNTER_MAX,
191	.policy		= nft_counter_policy,
192	.owner		= THIS_MODULE,
193};
194
195static void nft_counter_eval(const struct nft_expr *expr,
196			     struct nft_regs *regs,
197			     const struct nft_pktinfo *pkt)
198{
199	struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
200
201	nft_counter_do_eval(priv, regs, pkt);
202}
203
204static int nft_counter_dump(struct sk_buff *skb, const struct nft_expr *expr)
205{
206	struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
207
208	return nft_counter_do_dump(skb, priv, false);
209}
210
211static int nft_counter_init(const struct nft_ctx *ctx,
212			    const struct nft_expr *expr,
213			    const struct nlattr * const tb[])
214{
215	struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
216
217	return nft_counter_do_init(tb, priv);
218}
219
220static void nft_counter_destroy(const struct nft_ctx *ctx,
221				const struct nft_expr *expr)
222{
223	struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
224
225	nft_counter_do_destroy(priv);
226}
227
228static int nft_counter_clone(struct nft_expr *dst, const struct nft_expr *src)
229{
230	struct nft_counter_percpu_priv *priv = nft_expr_priv(src);
231	struct nft_counter_percpu_priv *priv_clone = nft_expr_priv(dst);
232	struct nft_counter __percpu *cpu_stats;
233	struct nft_counter *this_cpu;
234	struct nft_counter total;
235
236	nft_counter_fetch(priv, &total);
237
238	cpu_stats = alloc_percpu_gfp(struct nft_counter, GFP_ATOMIC);
239	if (cpu_stats == NULL)
240		return -ENOMEM;
241
242	preempt_disable();
243	this_cpu = this_cpu_ptr(cpu_stats);
244	this_cpu->packets = total.packets;
245	this_cpu->bytes = total.bytes;
246	preempt_enable();
247
248	priv_clone->counter = cpu_stats;
249	return 0;
250}
251
252static int nft_counter_offload(struct nft_offload_ctx *ctx,
253			       struct nft_flow_rule *flow,
254			       const struct nft_expr *expr)
255{
256	/* No specific offload action is needed, but report success. */
257	return 0;
258}
259
260static void nft_counter_offload_stats(struct nft_expr *expr,
261				      const struct flow_stats *stats)
262{
263	struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
264	struct nft_counter *this_cpu;
265	seqcount_t *myseq;
266
267	preempt_disable();
268	this_cpu = this_cpu_ptr(priv->counter);
269	myseq = this_cpu_ptr(&nft_counter_seq);
270
271	write_seqcount_begin(myseq);
272	this_cpu->packets += stats->pkts;
273	this_cpu->bytes += stats->bytes;
274	write_seqcount_end(myseq);
275	preempt_enable();
276}
277
278static struct nft_expr_type nft_counter_type;
279static const struct nft_expr_ops nft_counter_ops = {
280	.type		= &nft_counter_type,
281	.size		= NFT_EXPR_SIZE(sizeof(struct nft_counter_percpu_priv)),
282	.eval		= nft_counter_eval,
283	.init		= nft_counter_init,
284	.destroy	= nft_counter_destroy,
285	.destroy_clone	= nft_counter_destroy,
286	.dump		= nft_counter_dump,
287	.clone		= nft_counter_clone,
288	.offload	= nft_counter_offload,
289	.offload_stats	= nft_counter_offload_stats,
290};
291
292static struct nft_expr_type nft_counter_type __read_mostly = {
293	.name		= "counter",
294	.ops		= &nft_counter_ops,
295	.policy		= nft_counter_policy,
296	.maxattr	= NFTA_COUNTER_MAX,
297	.flags		= NFT_EXPR_STATEFUL,
298	.owner		= THIS_MODULE,
299};
300
301static int __init nft_counter_module_init(void)
302{
303	int cpu, err;
304
305	for_each_possible_cpu(cpu)
306		seqcount_init(per_cpu_ptr(&nft_counter_seq, cpu));
307
308	err = nft_register_obj(&nft_counter_obj_type);
309	if (err < 0)
310		return err;
311
312	err = nft_register_expr(&nft_counter_type);
313	if (err < 0)
314		goto err1;
315
316	return 0;
317err1:
318	nft_unregister_obj(&nft_counter_obj_type);
319	return err;
320}
321
322static void __exit nft_counter_module_exit(void)
323{
324	nft_unregister_expr(&nft_counter_type);
325	nft_unregister_obj(&nft_counter_obj_type);
326}
327
328module_init(nft_counter_module_init);
329module_exit(nft_counter_module_exit);
330
331MODULE_LICENSE("GPL");
332MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
333MODULE_ALIAS_NFT_EXPR("counter");
334MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_COUNTER);
335MODULE_DESCRIPTION("nftables counter rule support");