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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; | |
35 | struct list_head head; | |
36 | atomic_t refcnt; | |
37 | char name[NFACCT_NAME_MAX]; | |
38 | struct rcu_head rcu_head; | |
39 | }; | |
40 | ||
41 | static int | |
42 | nfnl_acct_new(struct sock *nfnl, struct sk_buff *skb, | |
43 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) | |
44 | { | |
45 | struct nf_acct *nfacct, *matching = NULL; | |
46 | char *acct_name; | |
47 | ||
48 | if (!tb[NFACCT_NAME]) | |
49 | return -EINVAL; | |
50 | ||
51 | acct_name = nla_data(tb[NFACCT_NAME]); | |
52 | ||
53 | list_for_each_entry(nfacct, &nfnl_acct_list, head) { | |
54 | if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0) | |
55 | continue; | |
56 | ||
57 | if (nlh->nlmsg_flags & NLM_F_EXCL) | |
58 | return -EEXIST; | |
59 | ||
60 | matching = nfacct; | |
61 | break; | |
62 | } | |
63 | ||
64 | if (matching) { | |
65 | if (nlh->nlmsg_flags & NLM_F_REPLACE) { | |
66 | /* reset counters if you request a replacement. */ | |
67 | atomic64_set(&matching->pkts, 0); | |
68 | atomic64_set(&matching->bytes, 0); | |
69 | return 0; | |
70 | } | |
71 | return -EBUSY; | |
72 | } | |
73 | ||
74 | nfacct = kzalloc(sizeof(struct nf_acct), GFP_KERNEL); | |
75 | if (nfacct == NULL) | |
76 | return -ENOMEM; | |
77 | ||
78 | strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX); | |
79 | ||
80 | if (tb[NFACCT_BYTES]) { | |
81 | atomic64_set(&nfacct->bytes, | |
fe31d1a8 | 82 | be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES]))); |
94139027 PNA |
83 | } |
84 | if (tb[NFACCT_PKTS]) { | |
85 | atomic64_set(&nfacct->pkts, | |
fe31d1a8 | 86 | be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS]))); |
94139027 PNA |
87 | } |
88 | atomic_set(&nfacct->refcnt, 1); | |
89 | list_add_tail_rcu(&nfacct->head, &nfnl_acct_list); | |
90 | return 0; | |
91 | } | |
92 | ||
93 | static int | |
94 | nfnl_acct_fill_info(struct sk_buff *skb, u32 pid, u32 seq, u32 type, | |
95 | int event, struct nf_acct *acct) | |
96 | { | |
97 | struct nlmsghdr *nlh; | |
98 | struct nfgenmsg *nfmsg; | |
99 | unsigned int flags = pid ? NLM_F_MULTI : 0; | |
100 | u64 pkts, bytes; | |
101 | ||
102 | event |= NFNL_SUBSYS_ACCT << 8; | |
103 | nlh = nlmsg_put(skb, pid, seq, event, sizeof(*nfmsg), flags); | |
104 | if (nlh == NULL) | |
105 | goto nlmsg_failure; | |
106 | ||
107 | nfmsg = nlmsg_data(nlh); | |
108 | nfmsg->nfgen_family = AF_UNSPEC; | |
109 | nfmsg->version = NFNETLINK_V0; | |
110 | nfmsg->res_id = 0; | |
111 | ||
7c801189 DM |
112 | if (nla_put_string(skb, NFACCT_NAME, acct->name)) |
113 | goto nla_put_failure; | |
94139027 PNA |
114 | |
115 | if (type == NFNL_MSG_ACCT_GET_CTRZERO) { | |
116 | pkts = atomic64_xchg(&acct->pkts, 0); | |
117 | bytes = atomic64_xchg(&acct->bytes, 0); | |
118 | } else { | |
119 | pkts = atomic64_read(&acct->pkts); | |
120 | bytes = atomic64_read(&acct->bytes); | |
121 | } | |
7c801189 DM |
122 | if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts)) || |
123 | nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes)) || | |
124 | nla_put_be32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt)))) | |
125 | goto nla_put_failure; | |
94139027 PNA |
126 | |
127 | nlmsg_end(skb, nlh); | |
128 | return skb->len; | |
129 | ||
130 | nlmsg_failure: | |
131 | nla_put_failure: | |
132 | nlmsg_cancel(skb, nlh); | |
133 | return -1; | |
134 | } | |
135 | ||
136 | static int | |
137 | nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb) | |
138 | { | |
139 | struct nf_acct *cur, *last; | |
140 | ||
141 | if (cb->args[2]) | |
142 | return 0; | |
143 | ||
144 | last = (struct nf_acct *)cb->args[1]; | |
145 | if (cb->args[1]) | |
146 | cb->args[1] = 0; | |
147 | ||
148 | rcu_read_lock(); | |
149 | list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { | |
150 | if (last && cur != last) | |
151 | continue; | |
152 | ||
153 | if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).pid, | |
154 | cb->nlh->nlmsg_seq, | |
155 | NFNL_MSG_TYPE(cb->nlh->nlmsg_type), | |
156 | NFNL_MSG_ACCT_NEW, cur) < 0) { | |
157 | cb->args[1] = (unsigned long)cur; | |
158 | break; | |
159 | } | |
160 | } | |
161 | if (!cb->args[1]) | |
162 | cb->args[2] = 1; | |
163 | rcu_read_unlock(); | |
164 | return skb->len; | |
165 | } | |
166 | ||
167 | static int | |
168 | nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb, | |
169 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) | |
170 | { | |
3ab0b245 | 171 | int ret = -ENOENT; |
94139027 PNA |
172 | struct nf_acct *cur; |
173 | char *acct_name; | |
174 | ||
175 | if (nlh->nlmsg_flags & NLM_F_DUMP) { | |
80d326fa PNA |
176 | struct netlink_dump_control c = { |
177 | .dump = nfnl_acct_dump, | |
178 | }; | |
179 | return netlink_dump_start(nfnl, skb, nlh, &c); | |
94139027 PNA |
180 | } |
181 | ||
182 | if (!tb[NFACCT_NAME]) | |
183 | return -EINVAL; | |
184 | acct_name = nla_data(tb[NFACCT_NAME]); | |
185 | ||
186 | list_for_each_entry(cur, &nfnl_acct_list, head) { | |
187 | struct sk_buff *skb2; | |
188 | ||
189 | if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) | |
190 | continue; | |
191 | ||
192 | skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); | |
3ab0b245 PNA |
193 | if (skb2 == NULL) { |
194 | ret = -ENOMEM; | |
94139027 | 195 | break; |
3ab0b245 | 196 | } |
94139027 PNA |
197 | |
198 | ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).pid, | |
199 | nlh->nlmsg_seq, | |
200 | NFNL_MSG_TYPE(nlh->nlmsg_type), | |
201 | NFNL_MSG_ACCT_NEW, cur); | |
3ab0b245 | 202 | if (ret <= 0) { |
94139027 | 203 | kfree_skb(skb2); |
3ab0b245 PNA |
204 | break; |
205 | } | |
206 | ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).pid, | |
207 | MSG_DONTWAIT); | |
208 | if (ret > 0) | |
209 | ret = 0; | |
94139027 | 210 | |
3ab0b245 PNA |
211 | /* this avoids a loop in nfnetlink. */ |
212 | return ret == -EAGAIN ? -ENOBUFS : ret; | |
94139027 PNA |
213 | } |
214 | return ret; | |
215 | } | |
216 | ||
217 | /* try to delete object, fail if it is still in use. */ | |
218 | static int nfnl_acct_try_del(struct nf_acct *cur) | |
219 | { | |
220 | int ret = 0; | |
221 | ||
222 | /* we want to avoid races with nfnl_acct_find_get. */ | |
223 | if (atomic_dec_and_test(&cur->refcnt)) { | |
224 | /* We are protected by nfnl mutex. */ | |
225 | list_del_rcu(&cur->head); | |
226 | kfree_rcu(cur, rcu_head); | |
227 | } else { | |
228 | /* still in use, restore reference counter. */ | |
229 | atomic_inc(&cur->refcnt); | |
230 | ret = -EBUSY; | |
231 | } | |
232 | return ret; | |
233 | } | |
234 | ||
235 | static int | |
236 | nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb, | |
237 | const struct nlmsghdr *nlh, const struct nlattr * const tb[]) | |
238 | { | |
239 | char *acct_name; | |
240 | struct nf_acct *cur; | |
241 | int ret = -ENOENT; | |
242 | ||
243 | if (!tb[NFACCT_NAME]) { | |
244 | list_for_each_entry(cur, &nfnl_acct_list, head) | |
245 | nfnl_acct_try_del(cur); | |
246 | ||
247 | return 0; | |
248 | } | |
249 | acct_name = nla_data(tb[NFACCT_NAME]); | |
250 | ||
251 | list_for_each_entry(cur, &nfnl_acct_list, head) { | |
252 | if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0) | |
253 | continue; | |
254 | ||
255 | ret = nfnl_acct_try_del(cur); | |
256 | if (ret < 0) | |
257 | return ret; | |
258 | ||
259 | break; | |
260 | } | |
261 | return ret; | |
262 | } | |
263 | ||
264 | static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = { | |
265 | [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 }, | |
266 | [NFACCT_BYTES] = { .type = NLA_U64 }, | |
267 | [NFACCT_PKTS] = { .type = NLA_U64 }, | |
268 | }; | |
269 | ||
270 | static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = { | |
271 | [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new, | |
272 | .attr_count = NFACCT_MAX, | |
273 | .policy = nfnl_acct_policy }, | |
274 | [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get, | |
275 | .attr_count = NFACCT_MAX, | |
276 | .policy = nfnl_acct_policy }, | |
277 | [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get, | |
278 | .attr_count = NFACCT_MAX, | |
279 | .policy = nfnl_acct_policy }, | |
280 | [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del, | |
281 | .attr_count = NFACCT_MAX, | |
282 | .policy = nfnl_acct_policy }, | |
283 | }; | |
284 | ||
285 | static const struct nfnetlink_subsystem nfnl_acct_subsys = { | |
286 | .name = "acct", | |
287 | .subsys_id = NFNL_SUBSYS_ACCT, | |
288 | .cb_count = NFNL_MSG_ACCT_MAX, | |
289 | .cb = nfnl_acct_cb, | |
290 | }; | |
291 | ||
292 | MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT); | |
293 | ||
294 | struct nf_acct *nfnl_acct_find_get(const char *acct_name) | |
295 | { | |
296 | struct nf_acct *cur, *acct = NULL; | |
297 | ||
298 | rcu_read_lock(); | |
299 | list_for_each_entry_rcu(cur, &nfnl_acct_list, head) { | |
300 | if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0) | |
301 | continue; | |
302 | ||
303 | if (!try_module_get(THIS_MODULE)) | |
304 | goto err; | |
305 | ||
306 | if (!atomic_inc_not_zero(&cur->refcnt)) { | |
307 | module_put(THIS_MODULE); | |
308 | goto err; | |
309 | } | |
310 | ||
311 | acct = cur; | |
312 | break; | |
313 | } | |
314 | err: | |
315 | rcu_read_unlock(); | |
316 | return acct; | |
317 | } | |
318 | EXPORT_SYMBOL_GPL(nfnl_acct_find_get); | |
319 | ||
320 | void nfnl_acct_put(struct nf_acct *acct) | |
321 | { | |
322 | atomic_dec(&acct->refcnt); | |
323 | module_put(THIS_MODULE); | |
324 | } | |
325 | EXPORT_SYMBOL_GPL(nfnl_acct_put); | |
326 | ||
327 | void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct) | |
328 | { | |
329 | atomic64_inc(&nfacct->pkts); | |
330 | atomic64_add(skb->len, &nfacct->bytes); | |
331 | } | |
332 | EXPORT_SYMBOL_GPL(nfnl_acct_update); | |
333 | ||
334 | static int __init nfnl_acct_init(void) | |
335 | { | |
336 | int ret; | |
337 | ||
338 | pr_info("nfnl_acct: registering with nfnetlink.\n"); | |
339 | ret = nfnetlink_subsys_register(&nfnl_acct_subsys); | |
340 | if (ret < 0) { | |
341 | pr_err("nfnl_acct_init: cannot register with nfnetlink.\n"); | |
342 | goto err_out; | |
343 | } | |
344 | return 0; | |
345 | err_out: | |
346 | return ret; | |
347 | } | |
348 | ||
349 | static void __exit nfnl_acct_exit(void) | |
350 | { | |
351 | struct nf_acct *cur, *tmp; | |
352 | ||
353 | pr_info("nfnl_acct: unregistering from nfnetlink.\n"); | |
354 | nfnetlink_subsys_unregister(&nfnl_acct_subsys); | |
355 | ||
356 | list_for_each_entry_safe(cur, tmp, &nfnl_acct_list, head) { | |
357 | list_del_rcu(&cur->head); | |
358 | /* We are sure that our objects have no clients at this point, | |
359 | * it's safe to release them all without checking refcnt. */ | |
360 | kfree_rcu(cur, rcu_head); | |
361 | } | |
362 | } | |
363 | ||
364 | module_init(nfnl_acct_init); | |
365 | module_exit(nfnl_acct_exit); |