tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
26MODULE_LICENSE("GPL");
27MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
28MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure");
29
30static LIST_HEAD(nfnl_acct_list);
31
32struct 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
41static int
42nfnl_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,
82 be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES])));
83 }
84 if (tb[NFACCT_PKTS]) {
85 atomic64_set(&nfacct->pkts,
86 be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS])));
87 }
88 atomic_set(&nfacct->refcnt, 1);
89 list_add_tail_rcu(&nfacct->head, &nfnl_acct_list);
90 return 0;
91}
92
93static int
94nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
95 int event, struct nf_acct *acct)
96{
97 struct nlmsghdr *nlh;
98 struct nfgenmsg *nfmsg;
99 unsigned int flags = portid ? NLM_F_MULTI : 0;
100 u64 pkts, bytes;
101
102 event |= NFNL_SUBSYS_ACCT << 8;
103 nlh = nlmsg_put(skb, portid, 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
112 if (nla_put_string(skb, NFACCT_NAME, acct->name))
113 goto nla_put_failure;
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 }
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;
126
127 nlmsg_end(skb, nlh);
128 return skb->len;
129
130nlmsg_failure:
131nla_put_failure:
132 nlmsg_cancel(skb, nlh);
133 return -1;
134}
135
136static int
137nfnl_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).portid,
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
167static int
168nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb,
169 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
170{
171 int ret = -ENOENT;
172 struct nf_acct *cur;
173 char *acct_name;
174
175 if (nlh->nlmsg_flags & NLM_F_DUMP) {
176 struct netlink_dump_control c = {
177 .dump = nfnl_acct_dump,
178 };
179 return netlink_dump_start(nfnl, skb, nlh, &c);
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);
193 if (skb2 == NULL) {
194 ret = -ENOMEM;
195 break;
196 }
197
198 ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid,
199 nlh->nlmsg_seq,
200 NFNL_MSG_TYPE(nlh->nlmsg_type),
201 NFNL_MSG_ACCT_NEW, cur);
202 if (ret <= 0) {
203 kfree_skb(skb2);
204 break;
205 }
206 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
207 MSG_DONTWAIT);
208 if (ret > 0)
209 ret = 0;
210
211 /* this avoids a loop in nfnetlink. */
212 return ret == -EAGAIN ? -ENOBUFS : ret;
213 }
214 return ret;
215}
216
217/* try to delete object, fail if it is still in use. */
218static 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
235static int
236nfnl_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
264static 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
270static 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
285static 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
292MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);
293
294struct 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 }
314err:
315 rcu_read_unlock();
316 return acct;
317}
318EXPORT_SYMBOL_GPL(nfnl_acct_find_get);
319
320void nfnl_acct_put(struct nf_acct *acct)
321{
322 atomic_dec(&acct->refcnt);
323 module_put(THIS_MODULE);
324}
325EXPORT_SYMBOL_GPL(nfnl_acct_put);
326
327void 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}
332EXPORT_SYMBOL_GPL(nfnl_acct_update);
333
334static 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;
345err_out:
346 return ret;
347}
348
349static 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
364module_init(nfnl_acct_init);
365module_exit(nfnl_acct_exit);