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9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/skbuff.h>
13#include <linux/atomic.h>
14#include <linux/refcount.h>
15#include <linux/netlink.h>
16#include <linux/rculist.h>
17#include <linux/slab.h>
18#include <linux/types.h>
19#include <linux/errno.h>
20#include <net/netlink.h>
21#include <net/sock.h>
22
23#include <linux/netfilter.h>
24#include <linux/netfilter/nfnetlink.h>
25#include <linux/netfilter/nfnetlink_acct.h>
26
27MODULE_LICENSE("GPL");
28MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
29MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure");
30
31struct nf_acct {
32 atomic64_t pkts;
33 atomic64_t bytes;
34 unsigned long flags;
35 struct list_head head;
36 refcount_t refcnt;
37 char name[NFACCT_NAME_MAX];
38 struct rcu_head rcu_head;
39 char data[0];
40};
41
42struct nfacct_filter {
43 u32 value;
44 u32 mask;
45};
46
47#define NFACCT_F_QUOTA (NFACCT_F_QUOTA_PKTS | NFACCT_F_QUOTA_BYTES)
48#define NFACCT_OVERQUOTA_BIT 2
49
50static int nfnl_acct_new(struct net *net, struct sock *nfnl,
51 struct sk_buff *skb, const struct nlmsghdr *nlh,
52 const struct nlattr * const tb[],
53 struct netlink_ext_ack *extack)
54{
55 struct nf_acct *nfacct, *matching = NULL;
56 char *acct_name;
57 unsigned int size = 0;
58 u32 flags = 0;
59
60 if (!tb[NFACCT_NAME])
61 return -EINVAL;
62
63 acct_name = nla_data(tb[NFACCT_NAME]);
64 if (strlen(acct_name) == 0)
65 return -EINVAL;
66
67 list_for_each_entry(nfacct, &net->nfnl_acct_list, head) {
68 if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0)
69 continue;
70
71 if (nlh->nlmsg_flags & NLM_F_EXCL)
72 return -EEXIST;
73
74 matching = nfacct;
75 break;
76 }
77
78 if (matching) {
79 if (nlh->nlmsg_flags & NLM_F_REPLACE) {
80
81 atomic64_set(&matching->pkts, 0);
82 atomic64_set(&matching->bytes, 0);
83 smp_mb__before_atomic();
84
85 if ((matching->flags & NFACCT_F_QUOTA))
86 clear_bit(NFACCT_OVERQUOTA_BIT,
87 &matching->flags);
88 return 0;
89 }
90 return -EBUSY;
91 }
92
93 if (tb[NFACCT_FLAGS]) {
94 flags = ntohl(nla_get_be32(tb[NFACCT_FLAGS]));
95 if (flags & ~NFACCT_F_QUOTA)
96 return -EOPNOTSUPP;
97 if ((flags & NFACCT_F_QUOTA) == NFACCT_F_QUOTA)
98 return -EINVAL;
99 if (flags & NFACCT_F_OVERQUOTA)
100 return -EINVAL;
101 if ((flags & NFACCT_F_QUOTA) && !tb[NFACCT_QUOTA])
102 return -EINVAL;
103
104 size += sizeof(u64);
105 }
106
107 nfacct = kzalloc(sizeof(struct nf_acct) + size, GFP_KERNEL);
108 if (nfacct == NULL)
109 return -ENOMEM;
110
111 if (flags & NFACCT_F_QUOTA) {
112 u64 *quota = (u64 *)nfacct->data;
113
114 *quota = be64_to_cpu(nla_get_be64(tb[NFACCT_QUOTA]));
115 nfacct->flags = flags;
116 }
117
118 strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX);
119
120 if (tb[NFACCT_BYTES]) {
121 atomic64_set(&nfacct->bytes,
122 be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES])));
123 }
124 if (tb[NFACCT_PKTS]) {
125 atomic64_set(&nfacct->pkts,
126 be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS])));
127 }
128 refcount_set(&nfacct->refcnt, 1);
129 list_add_tail_rcu(&nfacct->head, &net->nfnl_acct_list);
130 return 0;
131}
132
133static int
134nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
135 int event, struct nf_acct *acct)
136{
137 struct nlmsghdr *nlh;
138 struct nfgenmsg *nfmsg;
139 unsigned int flags = portid ? NLM_F_MULTI : 0;
140 u64 pkts, bytes;
141 u32 old_flags;
142
143 event = nfnl_msg_type(NFNL_SUBSYS_ACCT, event);
144 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
145 if (nlh == NULL)
146 goto nlmsg_failure;
147
148 nfmsg = nlmsg_data(nlh);
149 nfmsg->nfgen_family = AF_UNSPEC;
150 nfmsg->version = NFNETLINK_V0;
151 nfmsg->res_id = 0;
152
153 if (nla_put_string(skb, NFACCT_NAME, acct->name))
154 goto nla_put_failure;
155
156 old_flags = acct->flags;
157 if (type == NFNL_MSG_ACCT_GET_CTRZERO) {
158 pkts = atomic64_xchg(&acct->pkts, 0);
159 bytes = atomic64_xchg(&acct->bytes, 0);
160 smp_mb__before_atomic();
161 if (acct->flags & NFACCT_F_QUOTA)
162 clear_bit(NFACCT_OVERQUOTA_BIT, &acct->flags);
163 } else {
164 pkts = atomic64_read(&acct->pkts);
165 bytes = atomic64_read(&acct->bytes);
166 }
167 if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts),
168 NFACCT_PAD) ||
169 nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes),
170 NFACCT_PAD) ||
171 nla_put_be32(skb, NFACCT_USE, htonl(refcount_read(&acct->refcnt))))
172 goto nla_put_failure;
173 if (acct->flags & NFACCT_F_QUOTA) {
174 u64 *quota = (u64 *)acct->data;
175
176 if (nla_put_be32(skb, NFACCT_FLAGS, htonl(old_flags)) ||
177 nla_put_be64(skb, NFACCT_QUOTA, cpu_to_be64(*quota),
178 NFACCT_PAD))
179 goto nla_put_failure;
180 }
181 nlmsg_end(skb, nlh);
182 return skb->len;
183
184nlmsg_failure:
185nla_put_failure:
186 nlmsg_cancel(skb, nlh);
187 return -1;
188}
189
190static int
191nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
192{
193 struct net *net = sock_net(skb->sk);
194 struct nf_acct *cur, *last;
195 const struct nfacct_filter *filter = cb->data;
196
197 if (cb->args[2])
198 return 0;
199
200 last = (struct nf_acct *)cb->args[1];
201 if (cb->args[1])
202 cb->args[1] = 0;
203
204 rcu_read_lock();
205 list_for_each_entry_rcu(cur, &net->nfnl_acct_list, head) {
206 if (last) {
207 if (cur != last)
208 continue;
209
210 last = NULL;
211 }
212
213 if (filter && (cur->flags & filter->mask) != filter->value)
214 continue;
215
216 if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid,
217 cb->nlh->nlmsg_seq,
218 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
219 NFNL_MSG_ACCT_NEW, cur) < 0) {
220 cb->args[1] = (unsigned long)cur;
221 break;
222 }
223 }
224 if (!cb->args[1])
225 cb->args[2] = 1;
226 rcu_read_unlock();
227 return skb->len;
228}
229
230static int nfnl_acct_done(struct netlink_callback *cb)
231{
232 kfree(cb->data);
233 return 0;
234}
235
236static const struct nla_policy filter_policy[NFACCT_FILTER_MAX + 1] = {
237 [NFACCT_FILTER_MASK] = { .type = NLA_U32 },
238 [NFACCT_FILTER_VALUE] = { .type = NLA_U32 },
239};
240
241static struct nfacct_filter *
242nfacct_filter_alloc(const struct nlattr * const attr)
243{
244 struct nfacct_filter *filter;
245 struct nlattr *tb[NFACCT_FILTER_MAX + 1];
246 int err;
247
248 err = nla_parse_nested(tb, NFACCT_FILTER_MAX, attr, filter_policy,
249 NULL);
250 if (err < 0)
251 return ERR_PTR(err);
252
253 if (!tb[NFACCT_FILTER_MASK] || !tb[NFACCT_FILTER_VALUE])
254 return ERR_PTR(-EINVAL);
255
256 filter = kzalloc(sizeof(struct nfacct_filter), GFP_KERNEL);
257 if (!filter)
258 return ERR_PTR(-ENOMEM);
259
260 filter->mask = ntohl(nla_get_be32(tb[NFACCT_FILTER_MASK]));
261 filter->value = ntohl(nla_get_be32(tb[NFACCT_FILTER_VALUE]));
262
263 return filter;
264}
265
266static int nfnl_acct_get(struct net *net, struct sock *nfnl,
267 struct sk_buff *skb, const struct nlmsghdr *nlh,
268 const struct nlattr * const tb[],
269 struct netlink_ext_ack *extack)
270{
271 int ret = -ENOENT;
272 struct nf_acct *cur;
273 char *acct_name;
274
275 if (nlh->nlmsg_flags & NLM_F_DUMP) {
276 struct netlink_dump_control c = {
277 .dump = nfnl_acct_dump,
278 .done = nfnl_acct_done,
279 };
280
281 if (tb[NFACCT_FILTER]) {
282 struct nfacct_filter *filter;
283
284 filter = nfacct_filter_alloc(tb[NFACCT_FILTER]);
285 if (IS_ERR(filter))
286 return PTR_ERR(filter);
287
288 c.data = filter;
289 }
290 return netlink_dump_start(nfnl, skb, nlh, &c);
291 }
292
293 if (!tb[NFACCT_NAME])
294 return -EINVAL;
295 acct_name = nla_data(tb[NFACCT_NAME]);
296
297 list_for_each_entry(cur, &net->nfnl_acct_list, head) {
298 struct sk_buff *skb2;
299
300 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
301 continue;
302
303 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
304 if (skb2 == NULL) {
305 ret = -ENOMEM;
306 break;
307 }
308
309 ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid,
310 nlh->nlmsg_seq,
311 NFNL_MSG_TYPE(nlh->nlmsg_type),
312 NFNL_MSG_ACCT_NEW, cur);
313 if (ret <= 0) {
314 kfree_skb(skb2);
315 break;
316 }
317 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
318 MSG_DONTWAIT);
319 if (ret > 0)
320 ret = 0;
321
322
323 return ret == -EAGAIN ? -ENOBUFS : ret;
324 }
325 return ret;
326}
327
328
329static int nfnl_acct_try_del(struct nf_acct *cur)
330{
331 int ret = 0;
332
333
334
335
336 if (refcount_dec_if_one(&cur->refcnt)) {
337
338 list_del_rcu(&cur->head);
339 kfree_rcu(cur, rcu_head);
340 } else {
341 ret = -EBUSY;
342 }
343 return ret;
344}
345
346static int nfnl_acct_del(struct net *net, struct sock *nfnl,
347 struct sk_buff *skb, const struct nlmsghdr *nlh,
348 const struct nlattr * const tb[],
349 struct netlink_ext_ack *extack)
350{
351 struct nf_acct *cur, *tmp;
352 int ret = -ENOENT;
353 char *acct_name;
354
355 if (!tb[NFACCT_NAME]) {
356 list_for_each_entry_safe(cur, tmp, &net->nfnl_acct_list, head)
357 nfnl_acct_try_del(cur);
358
359 return 0;
360 }
361 acct_name = nla_data(tb[NFACCT_NAME]);
362
363 list_for_each_entry(cur, &net->nfnl_acct_list, head) {
364 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0)
365 continue;
366
367 ret = nfnl_acct_try_del(cur);
368 if (ret < 0)
369 return ret;
370
371 break;
372 }
373 return ret;
374}
375
376static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
377 [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
378 [NFACCT_BYTES] = { .type = NLA_U64 },
379 [NFACCT_PKTS] = { .type = NLA_U64 },
380 [NFACCT_FLAGS] = { .type = NLA_U32 },
381 [NFACCT_QUOTA] = { .type = NLA_U64 },
382 [NFACCT_FILTER] = {.type = NLA_NESTED },
383};
384
385static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
386 [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new,
387 .attr_count = NFACCT_MAX,
388 .policy = nfnl_acct_policy },
389 [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get,
390 .attr_count = NFACCT_MAX,
391 .policy = nfnl_acct_policy },
392 [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get,
393 .attr_count = NFACCT_MAX,
394 .policy = nfnl_acct_policy },
395 [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del,
396 .attr_count = NFACCT_MAX,
397 .policy = nfnl_acct_policy },
398};
399
400static const struct nfnetlink_subsystem nfnl_acct_subsys = {
401 .name = "acct",
402 .subsys_id = NFNL_SUBSYS_ACCT,
403 .cb_count = NFNL_MSG_ACCT_MAX,
404 .cb = nfnl_acct_cb,
405};
406
407MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);
408
409struct nf_acct *nfnl_acct_find_get(struct net *net, const char *acct_name)
410{
411 struct nf_acct *cur, *acct = NULL;
412
413 rcu_read_lock();
414 list_for_each_entry_rcu(cur, &net->nfnl_acct_list, head) {
415 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
416 continue;
417
418 if (!try_module_get(THIS_MODULE))
419 goto err;
420
421 if (!refcount_inc_not_zero(&cur->refcnt)) {
422 module_put(THIS_MODULE);
423 goto err;
424 }
425
426 acct = cur;
427 break;
428 }
429err:
430 rcu_read_unlock();
431 return acct;
432}
433EXPORT_SYMBOL_GPL(nfnl_acct_find_get);
434
435void nfnl_acct_put(struct nf_acct *acct)
436{
437 if (refcount_dec_and_test(&acct->refcnt))
438 kfree_rcu(acct, rcu_head);
439
440 module_put(THIS_MODULE);
441}
442EXPORT_SYMBOL_GPL(nfnl_acct_put);
443
444void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct)
445{
446 atomic64_inc(&nfacct->pkts);
447 atomic64_add(skb->len, &nfacct->bytes);
448}
449EXPORT_SYMBOL_GPL(nfnl_acct_update);
450
451static void nfnl_overquota_report(struct net *net, struct nf_acct *nfacct)
452{
453 int ret;
454 struct sk_buff *skb;
455
456 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
457 if (skb == NULL)
458 return;
459
460 ret = nfnl_acct_fill_info(skb, 0, 0, NFNL_MSG_ACCT_OVERQUOTA, 0,
461 nfacct);
462 if (ret <= 0) {
463 kfree_skb(skb);
464 return;
465 }
466 netlink_broadcast(net->nfnl, skb, 0, NFNLGRP_ACCT_QUOTA,
467 GFP_ATOMIC);
468}
469
470int nfnl_acct_overquota(struct net *net, const struct sk_buff *skb,
471 struct nf_acct *nfacct)
472{
473 u64 now;
474 u64 *quota;
475 int ret = NFACCT_UNDERQUOTA;
476
477
478 if (!(nfacct->flags & NFACCT_F_QUOTA))
479 return NFACCT_NO_QUOTA;
480
481 quota = (u64 *)nfacct->data;
482 now = (nfacct->flags & NFACCT_F_QUOTA_PKTS) ?
483 atomic64_read(&nfacct->pkts) : atomic64_read(&nfacct->bytes);
484
485 ret = now > *quota;
486
487 if (now >= *quota &&
488 !test_and_set_bit(NFACCT_OVERQUOTA_BIT, &nfacct->flags)) {
489 nfnl_overquota_report(net, nfacct);
490 }
491
492 return ret;
493}
494EXPORT_SYMBOL_GPL(nfnl_acct_overquota);
495
496static int __net_init nfnl_acct_net_init(struct net *net)
497{
498 INIT_LIST_HEAD(&net->nfnl_acct_list);
499
500 return 0;
501}
502
503static void __net_exit nfnl_acct_net_exit(struct net *net)
504{
505 struct nf_acct *cur, *tmp;
506
507 list_for_each_entry_safe(cur, tmp, &net->nfnl_acct_list, head) {
508 list_del_rcu(&cur->head);
509
510 if (refcount_dec_and_test(&cur->refcnt))
511 kfree_rcu(cur, rcu_head);
512 }
513}
514
515static struct pernet_operations nfnl_acct_ops = {
516 .init = nfnl_acct_net_init,
517 .exit = nfnl_acct_net_exit,
518};
519
520static int __init nfnl_acct_init(void)
521{
522 int ret;
523
524 ret = register_pernet_subsys(&nfnl_acct_ops);
525 if (ret < 0) {
526 pr_err("nfnl_acct_init: failed to register pernet ops\n");
527 goto err_out;
528 }
529
530 pr_info("nfnl_acct: registering with nfnetlink.\n");
531 ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
532 if (ret < 0) {
533 pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
534 goto cleanup_pernet;
535 }
536 return 0;
537
538cleanup_pernet:
539 unregister_pernet_subsys(&nfnl_acct_ops);
540err_out:
541 return ret;
542}
543
544static void __exit nfnl_acct_exit(void)
545{
546 pr_info("nfnl_acct: unregistering from nfnetlink.\n");
547 nfnetlink_subsys_unregister(&nfnl_acct_subsys);
548 unregister_pernet_subsys(&nfnl_acct_ops);
549}
550
551module_init(nfnl_acct_init);
552module_exit(nfnl_acct_exit);
553
