1 /*
2 * (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org>
3 * (C) 2011 Intra2net AG <http://www.intra2net.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation (or any later at your option).
8 */
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/netlink.h>
15 #include <linux/rculist.h>
16 #include <linux/slab.h>
17 #include <linux/types.h>
18 #include <linux/errno.h>
19 #include <net/netlink.h>
20 #include <net/sock.h>
21
22 #include <linux/netfilter.h>
23 #include <linux/netfilter/nfnetlink.h>
24 #include <linux/netfilter/nfnetlink_acct.h>
25
26 MODULE_LICENSE("GPL");
27 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
28 MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure");
29
30 struct nf_acct {
31 atomic64_t pkts;
32 atomic64_t bytes;
33 unsigned long flags;
34 struct list_head head;
35 atomic_t refcnt;
36 char name[NFACCT_NAME_MAX];
37 struct rcu_head rcu_head;
38 char data[0];
39 };
40
41 struct nfacct_filter {
42 u32 value;
43 u32 mask;
44 };
45
46 #define NFACCT_F_QUOTA (NFACCT_F_QUOTA_PKTS | NFACCT_F_QUOTA_BYTES)
47 #define NFACCT_OVERQUOTA_BIT 2 /* NFACCT_F_OVERQUOTA */
48
49 static int
50 nfnl_acct_new(struct sock *nfnl, struct sk_buff *skb,
51 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
52 {
53 struct nf_acct *nfacct, *matching = NULL;
54 struct net *net = sock_net(nfnl);
55 char *acct_name;
56 unsigned int size = 0;
57 u32 flags = 0;
58
59 if (!tb[NFACCT_NAME])
60 return -EINVAL;
61
62 acct_name = nla_data(tb[NFACCT_NAME]);
63 if (strlen(acct_name) == 0)
64 return -EINVAL;
65
66 list_for_each_entry(nfacct, &net->nfnl_acct_list, head) {
67 if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0)
68 continue;
69
70 if (nlh->nlmsg_flags & NLM_F_EXCL)
71 return -EEXIST;
72
73 matching = nfacct;
74 break;
75 }
76
77 if (matching) {
78 if (nlh->nlmsg_flags & NLM_F_REPLACE) {
79 /* reset counters if you request a replacement. */
80 atomic64_set(&matching->pkts, 0);
81 atomic64_set(&matching->bytes, 0);
82 smp_mb__before_atomic();
83 /* reset overquota flag if quota is enabled. */
84 if ((matching->flags & NFACCT_F_QUOTA))
85 clear_bit(NFACCT_OVERQUOTA_BIT,
86 &matching->flags);
87 return 0;
88 }
89 return -EBUSY;
90 }
91
92 if (tb[NFACCT_FLAGS]) {
93 flags = ntohl(nla_get_be32(tb[NFACCT_FLAGS]));
94 if (flags & ~NFACCT_F_QUOTA)
95 return -EOPNOTSUPP;
96 if ((flags & NFACCT_F_QUOTA) == NFACCT_F_QUOTA)
97 return -EINVAL;
98 if (flags & NFACCT_F_OVERQUOTA)
99 return -EINVAL;
100 if ((flags & NFACCT_F_QUOTA) && !tb[NFACCT_QUOTA])
101 return -EINVAL;
102
103 size += sizeof(u64);
104 }
105
106 nfacct = kzalloc(sizeof(struct nf_acct) + size, GFP_KERNEL);
107 if (nfacct == NULL)
108 return -ENOMEM;
109
110 if (flags & NFACCT_F_QUOTA) {
111 u64 *quota = (u64 *)nfacct->data;
112
113 *quota = be64_to_cpu(nla_get_be64(tb[NFACCT_QUOTA]));
114 nfacct->flags = flags;
115 }
116
117 strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX);
118
119 if (tb[NFACCT_BYTES]) {
120 atomic64_set(&nfacct->bytes,
121 be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES])));
122 }
123 if (tb[NFACCT_PKTS]) {
124 atomic64_set(&nfacct->pkts,
125 be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS])));
126 }
127 atomic_set(&nfacct->refcnt, 1);
128 list_add_tail_rcu(&nfacct->head, &net->nfnl_acct_list);
129 return 0;
130 }
131
132 static int
133 nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
134 int event, struct nf_acct *acct)
135 {
136 struct nlmsghdr *nlh;
137 struct nfgenmsg *nfmsg;
138 unsigned int flags = portid ? NLM_F_MULTI : 0;
139 u64 pkts, bytes;
140 u32 old_flags;
141
142 event |= NFNL_SUBSYS_ACCT << 8;
143 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
144 if (nlh == NULL)
145 goto nlmsg_failure;
146
147 nfmsg = nlmsg_data(nlh);
148 nfmsg->nfgen_family = AF_UNSPEC;
149 nfmsg->version = NFNETLINK_V0;
150 nfmsg->res_id = 0;
151
152 if (nla_put_string(skb, NFACCT_NAME, acct->name))
153 goto nla_put_failure;
154
155 old_flags = acct->flags;
156 if (type == NFNL_MSG_ACCT_GET_CTRZERO) {
157 pkts = atomic64_xchg(&acct->pkts, 0);
158 bytes = atomic64_xchg(&acct->bytes, 0);
159 smp_mb__before_atomic();
160 if (acct->flags & NFACCT_F_QUOTA)
161 clear_bit(NFACCT_OVERQUOTA_BIT, &acct->flags);
162 } else {
163 pkts = atomic64_read(&acct->pkts);
164 bytes = atomic64_read(&acct->bytes);
165 }
166 if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts)) ||
167 nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes)) ||
168 nla_put_be32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt))))
169 goto nla_put_failure;
170 if (acct->flags & NFACCT_F_QUOTA) {
171 u64 *quota = (u64 *)acct->data;
172
173 if (nla_put_be32(skb, NFACCT_FLAGS, htonl(old_flags)) ||
174 nla_put_be64(skb, NFACCT_QUOTA, cpu_to_be64(*quota)))
175 goto nla_put_failure;
176 }
177 nlmsg_end(skb, nlh);
178 return skb->len;
179
180 nlmsg_failure:
181 nla_put_failure:
182 nlmsg_cancel(skb, nlh);
183 return -1;
184 }
185
186 static int
187 nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
188 {
189 struct net *net = sock_net(skb->sk);
190 struct nf_acct *cur, *last;
191 const struct nfacct_filter *filter = cb->data;
192
193 if (cb->args[2])
194 return 0;
195
196 last = (struct nf_acct *)cb->args[1];
197 if (cb->args[1])
198 cb->args[1] = 0;
199
200 rcu_read_lock();
201 list_for_each_entry_rcu(cur, &net->nfnl_acct_list, head) {
202 if (last) {
203 if (cur != last)
204 continue;
205
206 last = NULL;
207 }
208
209 if (filter && (cur->flags & filter->mask) != filter->value)
210 continue;
211
212 if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid,
213 cb->nlh->nlmsg_seq,
214 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
215 NFNL_MSG_ACCT_NEW, cur) < 0) {
216 cb->args[1] = (unsigned long)cur;
217 break;
218 }
219 }
220 if (!cb->args[1])
221 cb->args[2] = 1;
222 rcu_read_unlock();
223 return skb->len;
224 }
225
226 static int nfnl_acct_done(struct netlink_callback *cb)
227 {
228 kfree(cb->data);
229 return 0;
230 }
231
232 static const struct nla_policy filter_policy[NFACCT_FILTER_MAX + 1] = {
233 [NFACCT_FILTER_MASK] = { .type = NLA_U32 },
234 [NFACCT_FILTER_VALUE] = { .type = NLA_U32 },
235 };
236
237 static struct nfacct_filter *
238 nfacct_filter_alloc(const struct nlattr * const attr)
239 {
240 struct nfacct_filter *filter;
241 struct nlattr *tb[NFACCT_FILTER_MAX + 1];
242 int err;
243
244 err = nla_parse_nested(tb, NFACCT_FILTER_MAX, attr, filter_policy);
245 if (err < 0)
246 return ERR_PTR(err);
247
248 if (!tb[NFACCT_FILTER_MASK] || !tb[NFACCT_FILTER_VALUE])
249 return ERR_PTR(-EINVAL);
250
251 filter = kzalloc(sizeof(struct nfacct_filter), GFP_KERNEL);
252 if (!filter)
253 return ERR_PTR(-ENOMEM);
254
255 filter->mask = ntohl(nla_get_be32(tb[NFACCT_FILTER_MASK]));
256 filter->value = ntohl(nla_get_be32(tb[NFACCT_FILTER_VALUE]));
257
258 return filter;
259 }
260
261 static int
262 nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb,
263 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
264 {
265 struct net *net = sock_net(nfnl);
266 int ret = -ENOENT;
267 struct nf_acct *cur;
268 char *acct_name;
269
270 if (nlh->nlmsg_flags & NLM_F_DUMP) {
271 struct netlink_dump_control c = {
272 .dump = nfnl_acct_dump,
273 .done = nfnl_acct_done,
274 };
275
276 if (tb[NFACCT_FILTER]) {
277 struct nfacct_filter *filter;
278
279 filter = nfacct_filter_alloc(tb[NFACCT_FILTER]);
280 if (IS_ERR(filter))
281 return PTR_ERR(filter);
282
283 c.data = filter;
284 }
285 return netlink_dump_start(nfnl, skb, nlh, &c);
286 }
287
288 if (!tb[NFACCT_NAME])
289 return -EINVAL;
290 acct_name = nla_data(tb[NFACCT_NAME]);
291
292 list_for_each_entry(cur, &net->nfnl_acct_list, head) {
293 struct sk_buff *skb2;
294
295 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
296 continue;
297
298 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
299 if (skb2 == NULL) {
300 ret = -ENOMEM;
301 break;
302 }
303
304 ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid,
305 nlh->nlmsg_seq,
306 NFNL_MSG_TYPE(nlh->nlmsg_type),
307 NFNL_MSG_ACCT_NEW, cur);
308 if (ret <= 0) {
309 kfree_skb(skb2);
310 break;
311 }
312 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
313 MSG_DONTWAIT);
314 if (ret > 0)
315 ret = 0;
316
317 /* this avoids a loop in nfnetlink. */
318 return ret == -EAGAIN ? -ENOBUFS : ret;
319 }
320 return ret;
321 }
322
323 /* try to delete object, fail if it is still in use. */
324 static int nfnl_acct_try_del(struct nf_acct *cur)
325 {
326 int ret = 0;
327
328 /* we want to avoid races with nfnl_acct_find_get. */
329 if (atomic_dec_and_test(&cur->refcnt)) {
330 /* We are protected by nfnl mutex. */
331 list_del_rcu(&cur->head);
332 kfree_rcu(cur, rcu_head);
333 } else {
334 /* still in use, restore reference counter. */
335 atomic_inc(&cur->refcnt);
336 ret = -EBUSY;
337 }
338 return ret;
339 }
340
341 static int
342 nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb,
343 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
344 {
345 struct net *net = sock_net(nfnl);
346 char *acct_name;
347 struct nf_acct *cur;
348 int ret = -ENOENT;
349
350 if (!tb[NFACCT_NAME]) {
351 list_for_each_entry(cur, &net->nfnl_acct_list, head)
352 nfnl_acct_try_del(cur);
353
354 return 0;
355 }
356 acct_name = nla_data(tb[NFACCT_NAME]);
357
358 list_for_each_entry(cur, &net->nfnl_acct_list, head) {
359 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0)
360 continue;
361
362 ret = nfnl_acct_try_del(cur);
363 if (ret < 0)
364 return ret;
365
366 break;
367 }
368 return ret;
369 }
370
371 static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
372 [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
373 [NFACCT_BYTES] = { .type = NLA_U64 },
374 [NFACCT_PKTS] = { .type = NLA_U64 },
375 [NFACCT_FLAGS] = { .type = NLA_U32 },
376 [NFACCT_QUOTA] = { .type = NLA_U64 },
377 [NFACCT_FILTER] = {.type = NLA_NESTED },
378 };
379
380 static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
381 [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new,
382 .attr_count = NFACCT_MAX,
383 .policy = nfnl_acct_policy },
384 [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get,
385 .attr_count = NFACCT_MAX,
386 .policy = nfnl_acct_policy },
387 [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get,
388 .attr_count = NFACCT_MAX,
389 .policy = nfnl_acct_policy },
390 [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del,
391 .attr_count = NFACCT_MAX,
392 .policy = nfnl_acct_policy },
393 };
394
395 static const struct nfnetlink_subsystem nfnl_acct_subsys = {
396 .name = "acct",
397 .subsys_id = NFNL_SUBSYS_ACCT,
398 .cb_count = NFNL_MSG_ACCT_MAX,
399 .cb = nfnl_acct_cb,
400 };
401
402 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);
403
404 struct nf_acct *nfnl_acct_find_get(struct net *net, const char *acct_name)
405 {
406 struct nf_acct *cur, *acct = NULL;
407
408 rcu_read_lock();
409 list_for_each_entry_rcu(cur, &net->nfnl_acct_list, head) {
410 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
411 continue;
412
413 if (!try_module_get(THIS_MODULE))
414 goto err;
415
416 if (!atomic_inc_not_zero(&cur->refcnt)) {
417 module_put(THIS_MODULE);
418 goto err;
419 }
420
421 acct = cur;
422 break;
423 }
424 err:
425 rcu_read_unlock();
426 return acct;
427 }
428 EXPORT_SYMBOL_GPL(nfnl_acct_find_get);
429
430 void nfnl_acct_put(struct nf_acct *acct)
431 {
432 if (atomic_dec_and_test(&acct->refcnt))
433 kfree_rcu(acct, rcu_head);
434
435 module_put(THIS_MODULE);
436 }
437 EXPORT_SYMBOL_GPL(nfnl_acct_put);
438
439 void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct)
440 {
441 atomic64_inc(&nfacct->pkts);
442 atomic64_add(skb->len, &nfacct->bytes);
443 }
444 EXPORT_SYMBOL_GPL(nfnl_acct_update);
445
446 static void nfnl_overquota_report(struct nf_acct *nfacct)
447 {
448 int ret;
449 struct sk_buff *skb;
450
451 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
452 if (skb == NULL)
453 return;
454
455 ret = nfnl_acct_fill_info(skb, 0, 0, NFNL_MSG_ACCT_OVERQUOTA, 0,
456 nfacct);
457 if (ret <= 0) {
458 kfree_skb(skb);
459 return;
460 }
461 netlink_broadcast(init_net.nfnl, skb, 0, NFNLGRP_ACCT_QUOTA,
462 GFP_ATOMIC);
463 }
464
465 int nfnl_acct_overquota(const struct sk_buff *skb, struct nf_acct *nfacct)
466 {
467 u64 now;
468 u64 *quota;
469 int ret = NFACCT_UNDERQUOTA;
470
471 /* no place here if we don't have a quota */
472 if (!(nfacct->flags & NFACCT_F_QUOTA))
473 return NFACCT_NO_QUOTA;
474
475 quota = (u64 *)nfacct->data;
476 now = (nfacct->flags & NFACCT_F_QUOTA_PKTS) ?
477 atomic64_read(&nfacct->pkts) : atomic64_read(&nfacct->bytes);
478
479 ret = now > *quota;
480
481 if (now >= *quota &&
482 !test_and_set_bit(NFACCT_OVERQUOTA_BIT, &nfacct->flags)) {
483 nfnl_overquota_report(nfacct);
484 }
485
486 return ret;
487 }
488 EXPORT_SYMBOL_GPL(nfnl_acct_overquota);
489
490 static int __net_init nfnl_acct_net_init(struct net *net)
491 {
492 INIT_LIST_HEAD(&net->nfnl_acct_list);
493
494 return 0;
495 }
496
497 static void __net_exit nfnl_acct_net_exit(struct net *net)
498 {
499 struct nf_acct *cur, *tmp;
500
501 list_for_each_entry_safe(cur, tmp, &net->nfnl_acct_list, head) {
502 list_del_rcu(&cur->head);
503
504 if (atomic_dec_and_test(&cur->refcnt))
505 kfree_rcu(cur, rcu_head);
506 }
507 }
508
509 static struct pernet_operations nfnl_acct_ops = {
510 .init = nfnl_acct_net_init,
511 .exit = nfnl_acct_net_exit,
512 };
513
514 static int __init nfnl_acct_init(void)
515 {
516 int ret;
517
518 ret = register_pernet_subsys(&nfnl_acct_ops);
519 if (ret < 0) {
520 pr_err("nfnl_acct_init: failed to register pernet ops\n");
521 goto err_out;
522 }
523
524 pr_info("nfnl_acct: registering with nfnetlink.\n");
525 ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
526 if (ret < 0) {
527 pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
528 goto cleanup_pernet;
529 }
530 return 0;
531
532 cleanup_pernet:
533 unregister_pernet_subsys(&nfnl_acct_ops);
534 err_out:
535 return ret;
536 }
537
538 static void __exit nfnl_acct_exit(void)
539 {
540 pr_info("nfnl_acct: unregistering from nfnetlink.\n");
541 nfnetlink_subsys_unregister(&nfnl_acct_subsys);
542 unregister_pernet_subsys(&nfnl_acct_ops);
543 }
544
545 module_init(nfnl_acct_init);
546 module_exit(nfnl_acct_exit);
547
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