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Commit | Line | Data |
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94139027 PNA |
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> | |
6523cf9a | 13 | #include <linux/atomic.h> |
94139027 PNA |
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> | |
94139027 PNA |
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 | static LIST_HEAD(nfnl_acct_list); | |
31 | ||
32 | struct nf_acct { | |
33 | atomic64_t pkts; | |
34 | atomic64_t bytes; | |
683399ed | 35 | unsigned long flags; |
94139027 PNA |
36 | struct list_head head; |
37 | atomic_t refcnt; | |
38 | char name[NFACCT_NAME_MAX]; | |
39 | struct rcu_head rcu_head; | |
683399ed | 40 | char data[0]; |
94139027 PNA |
41 | }; |
42 | ||
683399ed MP |
43 | #define NFACCT_F_QUOTA (NFACCT_F_QUOTA_PKTS | NFACCT_F_QUOTA_BYTES) |
44 | ||
94139027 PNA |
45 | static int |
46 | nfnl_acct_new(struct sock *nfnl, struct sk_buff *skb, | |
47 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) | |
48 | { | |
49 | struct nf_acct *nfacct, *matching = NULL; | |
50 | char *acct_name; | |
683399ed MP |
51 | unsigned int size = 0; |
52 | u32 flags = 0; | |
94139027 PNA |
53 | |
54 | if (!tb[NFACCT_NAME]) | |
55 | return -EINVAL; | |
56 | ||
57 | acct_name = nla_data(tb[NFACCT_NAME]); | |
deadcfc3 PNA |
58 | if (strlen(acct_name) == 0) |
59 | return -EINVAL; | |
94139027 PNA |
60 | |
61 | list_for_each_entry(nfacct, &nfnl_acct_list, head) { | |
62 | if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0) | |
63 | continue; | |
64 | ||
65 | if (nlh->nlmsg_flags & NLM_F_EXCL) | |
66 | return -EEXIST; | |
67 | ||
68 | matching = nfacct; | |
69 | break; | |
70 | } | |
71 | ||
72 | if (matching) { | |
73 | if (nlh->nlmsg_flags & NLM_F_REPLACE) { | |
74 | /* reset counters if you request a replacement. */ | |
75 | atomic64_set(&matching->pkts, 0); | |
76 | atomic64_set(&matching->bytes, 0); | |
f9da455b | 77 | smp_mb__before_atomic(); |
683399ed MP |
78 | /* reset overquota flag if quota is enabled. */ |
79 | if ((matching->flags & NFACCT_F_QUOTA)) | |
80 | clear_bit(NFACCT_F_OVERQUOTA, &matching->flags); | |
94139027 PNA |
81 | return 0; |
82 | } | |
83 | return -EBUSY; | |
84 | } | |
85 | ||
683399ed MP |
86 | if (tb[NFACCT_FLAGS]) { |
87 | flags = ntohl(nla_get_be32(tb[NFACCT_FLAGS])); | |
88 | if (flags & ~NFACCT_F_QUOTA) | |
89 | return -EOPNOTSUPP; | |
90 | if ((flags & NFACCT_F_QUOTA) == NFACCT_F_QUOTA) | |
91 | return -EINVAL; | |
92 | if (flags & NFACCT_F_OVERQUOTA) | |
93 | return -EINVAL; | |
94 | ||
95 | size += sizeof(u64); | |
96 | } | |
97 | ||
98 | nfacct = kzalloc(sizeof(struct nf_acct) + size, GFP_KERNEL); | |
94139027 PNA |
99 | if (nfacct == NULL) |
100 | return -ENOMEM; | |
101 | ||
683399ed MP |
102 | if (flags & NFACCT_F_QUOTA) { |
103 | u64 *quota = (u64 *)nfacct->data; | |
104 | ||
105 | *quota = be64_to_cpu(nla_get_be64(tb[NFACCT_QUOTA])); | |
106 | nfacct->flags = flags; | |
107 | } | |
108 | ||
94139027 PNA |
109 | strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX); |
110 | ||
111 | if (tb[NFACCT_BYTES]) { | |
112 | atomic64_set(&nfacct->bytes, | |
fe31d1a8 | 113 | be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES]))); |
94139027 PNA |
114 | } |
115 | if (tb[NFACCT_PKTS]) { | |
116 | atomic64_set(&nfacct->pkts, | |
fe31d1a8 | 117 | be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS]))); |
94139027 PNA |
118 | } |
119 | atomic_set(&nfacct->refcnt, 1); | |
120 | list_add_tail_rcu(&nfacct->head, &nfnl_acct_list); | |
121 | return 0; | |
122 | } | |
123 | ||
124 | static int | |
15e47304 | 125 | nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type, |
94139027 PNA |
126 | int event, struct nf_acct *acct) |
127 | { | |
128 | struct nlmsghdr *nlh; | |
129 | struct nfgenmsg *nfmsg; | |
15e47304 | 130 | unsigned int flags = portid ? NLM_F_MULTI : 0; |
94139027 PNA |
131 | u64 pkts, bytes; |
132 | ||
133 | event |= NFNL_SUBSYS_ACCT << 8; | |
15e47304 | 134 | nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags); |
94139027 PNA |
135 | if (nlh == NULL) |
136 | goto nlmsg_failure; | |
137 | ||
138 | nfmsg = nlmsg_data(nlh); | |
139 | nfmsg->nfgen_family = AF_UNSPEC; | |
140 | nfmsg->version = NFNETLINK_V0; | |
141 | nfmsg->res_id = 0; | |
142 | ||
7c801189 DM |
143 | if (nla_put_string(skb, NFACCT_NAME, acct->name)) |
144 | goto nla_put_failure; | |
94139027 PNA |
145 | |
146 | if (type == NFNL_MSG_ACCT_GET_CTRZERO) { | |
147 | pkts = atomic64_xchg(&acct->pkts, 0); | |
148 | bytes = atomic64_xchg(&acct->bytes, 0); | |
f9da455b | 149 | smp_mb__before_atomic(); |
683399ed MP |
150 | if (acct->flags & NFACCT_F_QUOTA) |
151 | clear_bit(NFACCT_F_OVERQUOTA, &acct->flags); | |
94139027 PNA |
152 | } else { |
153 | pkts = atomic64_read(&acct->pkts); | |
154 | bytes = atomic64_read(&acct->bytes); | |
155 | } | |
7c801189 DM |
156 | if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts)) || |
157 | nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes)) || | |
158 | nla_put_be32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt)))) | |
159 | goto nla_put_failure; | |
683399ed MP |
160 | if (acct->flags & NFACCT_F_QUOTA) { |
161 | u64 *quota = (u64 *)acct->data; | |
94139027 | 162 | |
683399ed MP |
163 | if (nla_put_be32(skb, NFACCT_FLAGS, htonl(acct->flags)) || |
164 | nla_put_be64(skb, NFACCT_QUOTA, cpu_to_be64(*quota))) | |
165 | goto nla_put_failure; | |
166 | } | |
94139027 PNA |
167 | nlmsg_end(skb, nlh); |
168 | return skb->len; | |
169 | ||
170 | nlmsg_failure: | |
171 | nla_put_failure: | |
172 | nlmsg_cancel(skb, nlh); | |
173 | return -1; | |
174 | } | |
175 | ||
176 | static int | |
177 | nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb) | |
178 | { | |
179 | struct nf_acct *cur, *last; | |
180 | ||
181 | if (cb->args[2]) | |
182 | return 0; | |
183 | ||
184 | last = (struct nf_acct *)cb->args[1]; | |
185 | if (cb->args[1]) | |
186 | cb->args[1] = 0; | |
187 | ||
188 | rcu_read_lock(); | |
189 | list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { | |
991a6b73 PNA |
190 | if (last) { |
191 | if (cur != last) | |
192 | continue; | |
94139027 | 193 | |
991a6b73 PNA |
194 | last = NULL; |
195 | } | |
15e47304 | 196 | if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid, |
94139027 PNA |
197 | cb->nlh->nlmsg_seq, |
198 | NFNL_MSG_TYPE(cb->nlh->nlmsg_type), | |
199 | NFNL_MSG_ACCT_NEW, cur) < 0) { | |
200 | cb->args[1] = (unsigned long)cur; | |
201 | break; | |
202 | } | |
203 | } | |
204 | if (!cb->args[1]) | |
205 | cb->args[2] = 1; | |
206 | rcu_read_unlock(); | |
207 | return skb->len; | |
208 | } | |
209 | ||
210 | static int | |
211 | nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb, | |
212 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) | |
213 | { | |
3ab0b245 | 214 | int ret = -ENOENT; |
94139027 PNA |
215 | struct nf_acct *cur; |
216 | char *acct_name; | |
217 | ||
218 | if (nlh->nlmsg_flags & NLM_F_DUMP) { | |
80d326fa PNA |
219 | struct netlink_dump_control c = { |
220 | .dump = nfnl_acct_dump, | |
221 | }; | |
222 | return netlink_dump_start(nfnl, skb, nlh, &c); | |
94139027 PNA |
223 | } |
224 | ||
225 | if (!tb[NFACCT_NAME]) | |
226 | return -EINVAL; | |
227 | acct_name = nla_data(tb[NFACCT_NAME]); | |
228 | ||
229 | list_for_each_entry(cur, &nfnl_acct_list, head) { | |
230 | struct sk_buff *skb2; | |
231 | ||
232 | if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) | |
233 | continue; | |
234 | ||
235 | skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); | |
3ab0b245 PNA |
236 | if (skb2 == NULL) { |
237 | ret = -ENOMEM; | |
94139027 | 238 | break; |
3ab0b245 | 239 | } |
94139027 | 240 | |
15e47304 | 241 | ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid, |
94139027 PNA |
242 | nlh->nlmsg_seq, |
243 | NFNL_MSG_TYPE(nlh->nlmsg_type), | |
244 | NFNL_MSG_ACCT_NEW, cur); | |
3ab0b245 | 245 | if (ret <= 0) { |
94139027 | 246 | kfree_skb(skb2); |
3ab0b245 PNA |
247 | break; |
248 | } | |
15e47304 | 249 | ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid, |
3ab0b245 PNA |
250 | MSG_DONTWAIT); |
251 | if (ret > 0) | |
252 | ret = 0; | |
94139027 | 253 | |
3ab0b245 PNA |
254 | /* this avoids a loop in nfnetlink. */ |
255 | return ret == -EAGAIN ? -ENOBUFS : ret; | |
94139027 PNA |
256 | } |
257 | return ret; | |
258 | } | |
259 | ||
260 | /* try to delete object, fail if it is still in use. */ | |
261 | static int nfnl_acct_try_del(struct nf_acct *cur) | |
262 | { | |
263 | int ret = 0; | |
264 | ||
265 | /* we want to avoid races with nfnl_acct_find_get. */ | |
266 | if (atomic_dec_and_test(&cur->refcnt)) { | |
267 | /* We are protected by nfnl mutex. */ | |
268 | list_del_rcu(&cur->head); | |
269 | kfree_rcu(cur, rcu_head); | |
270 | } else { | |
271 | /* still in use, restore reference counter. */ | |
272 | atomic_inc(&cur->refcnt); | |
273 | ret = -EBUSY; | |
274 | } | |
275 | return ret; | |
276 | } | |
277 | ||
278 | static int | |
279 | nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb, | |
280 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) | |
281 | { | |
282 | char *acct_name; | |
283 | struct nf_acct *cur; | |
284 | int ret = -ENOENT; | |
285 | ||
286 | if (!tb[NFACCT_NAME]) { | |
287 | list_for_each_entry(cur, &nfnl_acct_list, head) | |
288 | nfnl_acct_try_del(cur); | |
289 | ||
290 | return 0; | |
291 | } | |
292 | acct_name = nla_data(tb[NFACCT_NAME]); | |
293 | ||
294 | list_for_each_entry(cur, &nfnl_acct_list, head) { | |
295 | if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0) | |
296 | continue; | |
297 | ||
298 | ret = nfnl_acct_try_del(cur); | |
299 | if (ret < 0) | |
300 | return ret; | |
301 | ||
302 | break; | |
303 | } | |
304 | return ret; | |
305 | } | |
306 | ||
307 | static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = { | |
308 | [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 }, | |
309 | [NFACCT_BYTES] = { .type = NLA_U64 }, | |
310 | [NFACCT_PKTS] = { .type = NLA_U64 }, | |
683399ed MP |
311 | [NFACCT_FLAGS] = { .type = NLA_U32 }, |
312 | [NFACCT_QUOTA] = { .type = NLA_U64 }, | |
94139027 PNA |
313 | }; |
314 | ||
315 | static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = { | |
316 | [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new, | |
317 | .attr_count = NFACCT_MAX, | |
318 | .policy = nfnl_acct_policy }, | |
319 | [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get, | |
320 | .attr_count = NFACCT_MAX, | |
321 | .policy = nfnl_acct_policy }, | |
322 | [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get, | |
323 | .attr_count = NFACCT_MAX, | |
324 | .policy = nfnl_acct_policy }, | |
325 | [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del, | |
326 | .attr_count = NFACCT_MAX, | |
327 | .policy = nfnl_acct_policy }, | |
328 | }; | |
329 | ||
330 | static const struct nfnetlink_subsystem nfnl_acct_subsys = { | |
331 | .name = "acct", | |
332 | .subsys_id = NFNL_SUBSYS_ACCT, | |
333 | .cb_count = NFNL_MSG_ACCT_MAX, | |
334 | .cb = nfnl_acct_cb, | |
335 | }; | |
336 | ||
337 | MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT); | |
338 | ||
339 | struct nf_acct *nfnl_acct_find_get(const char *acct_name) | |
340 | { | |
341 | struct nf_acct *cur, *acct = NULL; | |
342 | ||
343 | rcu_read_lock(); | |
344 | list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { | |
345 | if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) | |
346 | continue; | |
347 | ||
348 | if (!try_module_get(THIS_MODULE)) | |
349 | goto err; | |
350 | ||
351 | if (!atomic_inc_not_zero(&cur->refcnt)) { | |
352 | module_put(THIS_MODULE); | |
353 | goto err; | |
354 | } | |
355 | ||
356 | acct = cur; | |
357 | break; | |
358 | } | |
359 | err: | |
360 | rcu_read_unlock(); | |
361 | return acct; | |
362 | } | |
363 | EXPORT_SYMBOL_GPL(nfnl_acct_find_get); | |
364 | ||
365 | void nfnl_acct_put(struct nf_acct *acct) | |
366 | { | |
367 | atomic_dec(&acct->refcnt); | |
368 | module_put(THIS_MODULE); | |
369 | } | |
370 | EXPORT_SYMBOL_GPL(nfnl_acct_put); | |
371 | ||
372 | void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct) | |
373 | { | |
374 | atomic64_inc(&nfacct->pkts); | |
375 | atomic64_add(skb->len, &nfacct->bytes); | |
376 | } | |
377 | EXPORT_SYMBOL_GPL(nfnl_acct_update); | |
378 | ||
683399ed MP |
379 | static void nfnl_overquota_report(struct nf_acct *nfacct) |
380 | { | |
381 | int ret; | |
382 | struct sk_buff *skb; | |
383 | ||
384 | skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); | |
385 | if (skb == NULL) | |
386 | return; | |
387 | ||
388 | ret = nfnl_acct_fill_info(skb, 0, 0, NFNL_MSG_ACCT_OVERQUOTA, 0, | |
389 | nfacct); | |
390 | if (ret <= 0) { | |
391 | kfree_skb(skb); | |
392 | return; | |
393 | } | |
394 | netlink_broadcast(init_net.nfnl, skb, 0, NFNLGRP_ACCT_QUOTA, | |
395 | GFP_ATOMIC); | |
396 | } | |
397 | ||
398 | int nfnl_acct_overquota(const struct sk_buff *skb, struct nf_acct *nfacct) | |
399 | { | |
400 | u64 now; | |
401 | u64 *quota; | |
402 | int ret = NFACCT_UNDERQUOTA; | |
403 | ||
404 | /* no place here if we don't have a quota */ | |
405 | if (!(nfacct->flags & NFACCT_F_QUOTA)) | |
406 | return NFACCT_NO_QUOTA; | |
407 | ||
408 | quota = (u64 *)nfacct->data; | |
409 | now = (nfacct->flags & NFACCT_F_QUOTA_PKTS) ? | |
410 | atomic64_read(&nfacct->pkts) : atomic64_read(&nfacct->bytes); | |
411 | ||
412 | ret = now > *quota; | |
413 | ||
414 | if (now >= *quota && | |
415 | !test_and_set_bit(NFACCT_F_OVERQUOTA, &nfacct->flags)) { | |
416 | nfnl_overquota_report(nfacct); | |
417 | } | |
418 | ||
419 | return ret; | |
420 | } | |
421 | EXPORT_SYMBOL_GPL(nfnl_acct_overquota); | |
422 | ||
94139027 PNA |
423 | static int __init nfnl_acct_init(void) |
424 | { | |
425 | int ret; | |
426 | ||
427 | pr_info("nfnl_acct: registering with nfnetlink.\n"); | |
428 | ret = nfnetlink_subsys_register(&nfnl_acct_subsys); | |
429 | if (ret < 0) { | |
430 | pr_err("nfnl_acct_init: cannot register with nfnetlink.\n"); | |
431 | goto err_out; | |
432 | } | |
433 | return 0; | |
434 | err_out: | |
435 | return ret; | |
436 | } | |
437 | ||
438 | static void __exit nfnl_acct_exit(void) | |
439 | { | |
440 | struct nf_acct *cur, *tmp; | |
441 | ||
442 | pr_info("nfnl_acct: unregistering from nfnetlink.\n"); | |
443 | nfnetlink_subsys_unregister(&nfnl_acct_subsys); | |
444 | ||
445 | list_for_each_entry_safe(cur, tmp, &nfnl_acct_list, head) { | |
446 | list_del_rcu(&cur->head); | |
447 | /* We are sure that our objects have no clients at this point, | |
448 | * it's safe to release them all without checking refcnt. */ | |
449 | kfree_rcu(cur, rcu_head); | |
450 | } | |
451 | } | |
452 | ||
453 | module_init(nfnl_acct_init); | |
454 | module_exit(nfnl_acct_exit); |