1
2
3
4
5
6
7
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 if (strlen(acct_name) == 0)
53 return -EINVAL;
54
55 list_for_each_entry(nfacct, &nfnl_acct_list, head) {
56 if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0)
57 continue;
58
59 if (nlh->nlmsg_flags & NLM_F_EXCL)
60 return -EEXIST;
61
62 matching = nfacct;
63 break;
64 }
65
66 if (matching) {
67 if (nlh->nlmsg_flags & NLM_F_REPLACE) {
68
69 atomic64_set(&matching->pkts, 0);
70 atomic64_set(&matching->bytes, 0);
71 return 0;
72 }
73 return -EBUSY;
74 }
75
76 nfacct = kzalloc(sizeof(struct nf_acct), GFP_KERNEL);
77 if (nfacct == NULL)
78 return -ENOMEM;
79
80 strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX);
81
82 if (tb[NFACCT_BYTES]) {
83 atomic64_set(&nfacct->bytes,
84 be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES])));
85 }
86 if (tb[NFACCT_PKTS]) {
87 atomic64_set(&nfacct->pkts,
88 be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS])));
89 }
90 atomic_set(&nfacct->refcnt, 1);
91 list_add_tail_rcu(&nfacct->head, &nfnl_acct_list);
92 return 0;
93}
94
95static int
96nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
97 int event, struct nf_acct *acct)
98{
99 struct nlmsghdr *nlh;
100 struct nfgenmsg *nfmsg;
101 unsigned int flags = portid ? NLM_F_MULTI : 0;
102 u64 pkts, bytes;
103
104 event |= NFNL_SUBSYS_ACCT << 8;
105 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
106 if (nlh == NULL)
107 goto nlmsg_failure;
108
109 nfmsg = nlmsg_data(nlh);
110 nfmsg->nfgen_family = AF_UNSPEC;
111 nfmsg->version = NFNETLINK_V0;
112 nfmsg->res_id = 0;
113
114 if (nla_put_string(skb, NFACCT_NAME, acct->name))
115 goto nla_put_failure;
116
117 if (type == NFNL_MSG_ACCT_GET_CTRZERO) {
118 pkts = atomic64_xchg(&acct->pkts, 0);
119 bytes = atomic64_xchg(&acct->bytes, 0);
120 } else {
121 pkts = atomic64_read(&acct->pkts);
122 bytes = atomic64_read(&acct->bytes);
123 }
124 if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts)) ||
125 nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes)) ||
126 nla_put_be32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt))))
127 goto nla_put_failure;
128
129 nlmsg_end(skb, nlh);
130 return skb->len;
131
132nlmsg_failure:
133nla_put_failure:
134 nlmsg_cancel(skb, nlh);
135 return -1;
136}
137
138static int
139nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
140{
141 struct nf_acct *cur, *last;
142
143 if (cb->args[2])
144 return 0;
145
146 last = (struct nf_acct *)cb->args[1];
147 if (cb->args[1])
148 cb->args[1] = 0;
149
150 rcu_read_lock();
151 list_for_each_entry_rcu(cur, &nfnl_acct_list, head) {
152 if (last && cur != last)
153 continue;
154
155 if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid,
156 cb->nlh->nlmsg_seq,
157 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
158 NFNL_MSG_ACCT_NEW, cur) < 0) {
159 cb->args[1] = (unsigned long)cur;
160 break;
161 }
162 }
163 if (!cb->args[1])
164 cb->args[2] = 1;
165 rcu_read_unlock();
166 return skb->len;
167}
168
169static int
170nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb,
171 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
172{
173 int ret = -ENOENT;
174 struct nf_acct *cur;
175 char *acct_name;
176
177 if (nlh->nlmsg_flags & NLM_F_DUMP) {
178 struct netlink_dump_control c = {
179 .dump = nfnl_acct_dump,
180 };
181 return netlink_dump_start(nfnl, skb, nlh, &c);
182 }
183
184 if (!tb[NFACCT_NAME])
185 return -EINVAL;
186 acct_name = nla_data(tb[NFACCT_NAME]);
187
188 list_for_each_entry(cur, &nfnl_acct_list, head) {
189 struct sk_buff *skb2;
190
191 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
192 continue;
193
194 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
195 if (skb2 == NULL) {
196 ret = -ENOMEM;
197 break;
198 }
199
200 ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid,
201 nlh->nlmsg_seq,
202 NFNL_MSG_TYPE(nlh->nlmsg_type),
203 NFNL_MSG_ACCT_NEW, cur);
204 if (ret <= 0) {
205 kfree_skb(skb2);
206 break;
207 }
208 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
209 MSG_DONTWAIT);
210 if (ret > 0)
211 ret = 0;
212
213
214 return ret == -EAGAIN ? -ENOBUFS : ret;
215 }
216 return ret;
217}
218
219
220static int nfnl_acct_try_del(struct nf_acct *cur)
221{
222 int ret = 0;
223
224
225 if (atomic_dec_and_test(&cur->refcnt)) {
226
227 list_del_rcu(&cur->head);
228 kfree_rcu(cur, rcu_head);
229 } else {
230
231 atomic_inc(&cur->refcnt);
232 ret = -EBUSY;
233 }
234 return ret;
235}
236
237static int
238nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb,
239 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
240{
241 char *acct_name;
242 struct nf_acct *cur;
243 int ret = -ENOENT;
244
245 if (!tb[NFACCT_NAME]) {
246 list_for_each_entry(cur, &nfnl_acct_list, head)
247 nfnl_acct_try_del(cur);
248
249 return 0;
250 }
251 acct_name = nla_data(tb[NFACCT_NAME]);
252
253 list_for_each_entry(cur, &nfnl_acct_list, head) {
254 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0)
255 continue;
256
257 ret = nfnl_acct_try_del(cur);
258 if (ret < 0)
259 return ret;
260
261 break;
262 }
263 return ret;
264}
265
266static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
267 [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
268 [NFACCT_BYTES] = { .type = NLA_U64 },
269 [NFACCT_PKTS] = { .type = NLA_U64 },
270};
271
272static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
273 [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new,
274 .attr_count = NFACCT_MAX,
275 .policy = nfnl_acct_policy },
276 [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get,
277 .attr_count = NFACCT_MAX,
278 .policy = nfnl_acct_policy },
279 [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get,
280 .attr_count = NFACCT_MAX,
281 .policy = nfnl_acct_policy },
282 [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del,
283 .attr_count = NFACCT_MAX,
284 .policy = nfnl_acct_policy },
285};
286
287static const struct nfnetlink_subsystem nfnl_acct_subsys = {
288 .name = "acct",
289 .subsys_id = NFNL_SUBSYS_ACCT,
290 .cb_count = NFNL_MSG_ACCT_MAX,
291 .cb = nfnl_acct_cb,
292};
293
294MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);
295
296struct nf_acct *nfnl_acct_find_get(const char *acct_name)
297{
298 struct nf_acct *cur, *acct = NULL;
299
300 rcu_read_lock();
301 list_for_each_entry_rcu(cur, &nfnl_acct_list, head) {
302 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
303 continue;
304
305 if (!try_module_get(THIS_MODULE))
306 goto err;
307
308 if (!atomic_inc_not_zero(&cur->refcnt)) {
309 module_put(THIS_MODULE);
310 goto err;
311 }
312
313 acct = cur;
314 break;
315 }
316err:
317 rcu_read_unlock();
318 return acct;
319}
320EXPORT_SYMBOL_GPL(nfnl_acct_find_get);
321
322void nfnl_acct_put(struct nf_acct *acct)
323{
324 atomic_dec(&acct->refcnt);
325 module_put(THIS_MODULE);
326}
327EXPORT_SYMBOL_GPL(nfnl_acct_put);
328
329void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct)
330{
331 atomic64_inc(&nfacct->pkts);
332 atomic64_add(skb->len, &nfacct->bytes);
333}
334EXPORT_SYMBOL_GPL(nfnl_acct_update);
335
336static int __init nfnl_acct_init(void)
337{
338 int ret;
339
340 pr_info("nfnl_acct: registering with nfnetlink.\n");
341 ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
342 if (ret < 0) {
343 pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
344 goto err_out;
345 }
346 return 0;
347err_out:
348 return ret;
349}
350
351static void __exit nfnl_acct_exit(void)
352{
353 struct nf_acct *cur, *tmp;
354
355 pr_info("nfnl_acct: unregistering from nfnetlink.\n");
356 nfnetlink_subsys_unregister(&nfnl_acct_subsys);
357
358 list_for_each_entry_safe(cur, tmp, &nfnl_acct_list, head) {
359 list_del_rcu(&cur->head);
360
361
362 kfree_rcu(cur, rcu_head);
363 }
364}
365
366module_init(nfnl_acct_init);
367module_exit(nfnl_acct_exit);
368
