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) {
153 if (cur != last)
154 continue;
155
156 last = NULL;
157 }
158 if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid,
159 cb->nlh->nlmsg_seq,
160 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
161 NFNL_MSG_ACCT_NEW, cur) < 0) {
162 cb->args[1] = (unsigned long)cur;
163 break;
164 }
165 }
166 if (!cb->args[1])
167 cb->args[2] = 1;
168 rcu_read_unlock();
169 return skb->len;
170}
171
172static int
173nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb,
174 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
175{
176 int ret = -ENOENT;
177 struct nf_acct *cur;
178 char *acct_name;
179
180 if (nlh->nlmsg_flags & NLM_F_DUMP) {
181 struct netlink_dump_control c = {
182 .dump = nfnl_acct_dump,
183 };
184 return netlink_dump_start(nfnl, skb, nlh, &c);
185 }
186
187 if (!tb[NFACCT_NAME])
188 return -EINVAL;
189 acct_name = nla_data(tb[NFACCT_NAME]);
190
191 list_for_each_entry(cur, &nfnl_acct_list, head) {
192 struct sk_buff *skb2;
193
194 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
195 continue;
196
197 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
198 if (skb2 == NULL) {
199 ret = -ENOMEM;
200 break;
201 }
202
203 ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid,
204 nlh->nlmsg_seq,
205 NFNL_MSG_TYPE(nlh->nlmsg_type),
206 NFNL_MSG_ACCT_NEW, cur);
207 if (ret <= 0) {
208 kfree_skb(skb2);
209 break;
210 }
211 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
212 MSG_DONTWAIT);
213 if (ret > 0)
214 ret = 0;
215
216
217 return ret == -EAGAIN ? -ENOBUFS : ret;
218 }
219 return ret;
220}
221
222
223static int nfnl_acct_try_del(struct nf_acct *cur)
224{
225 int ret = 0;
226
227
228 if (atomic_dec_and_test(&cur->refcnt)) {
229
230 list_del_rcu(&cur->head);
231 kfree_rcu(cur, rcu_head);
232 } else {
233
234 atomic_inc(&cur->refcnt);
235 ret = -EBUSY;
236 }
237 return ret;
238}
239
240static int
241nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb,
242 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
243{
244 char *acct_name;
245 struct nf_acct *cur;
246 int ret = -ENOENT;
247
248 if (!tb[NFACCT_NAME]) {
249 list_for_each_entry(cur, &nfnl_acct_list, head)
250 nfnl_acct_try_del(cur);
251
252 return 0;
253 }
254 acct_name = nla_data(tb[NFACCT_NAME]);
255
256 list_for_each_entry(cur, &nfnl_acct_list, head) {
257 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0)
258 continue;
259
260 ret = nfnl_acct_try_del(cur);
261 if (ret < 0)
262 return ret;
263
264 break;
265 }
266 return ret;
267}
268
269static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
270 [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
271 [NFACCT_BYTES] = { .type = NLA_U64 },
272 [NFACCT_PKTS] = { .type = NLA_U64 },
273};
274
275static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
276 [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new,
277 .attr_count = NFACCT_MAX,
278 .policy = nfnl_acct_policy },
279 [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get,
280 .attr_count = NFACCT_MAX,
281 .policy = nfnl_acct_policy },
282 [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get,
283 .attr_count = NFACCT_MAX,
284 .policy = nfnl_acct_policy },
285 [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del,
286 .attr_count = NFACCT_MAX,
287 .policy = nfnl_acct_policy },
288};
289
290static const struct nfnetlink_subsystem nfnl_acct_subsys = {
291 .name = "acct",
292 .subsys_id = NFNL_SUBSYS_ACCT,
293 .cb_count = NFNL_MSG_ACCT_MAX,
294 .cb = nfnl_acct_cb,
295};
296
297MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);
298
299struct nf_acct *nfnl_acct_find_get(const char *acct_name)
300{
301 struct nf_acct *cur, *acct = NULL;
302
303 rcu_read_lock();
304 list_for_each_entry_rcu(cur, &nfnl_acct_list, head) {
305 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
306 continue;
307
308 if (!try_module_get(THIS_MODULE))
309 goto err;
310
311 if (!atomic_inc_not_zero(&cur->refcnt)) {
312 module_put(THIS_MODULE);
313 goto err;
314 }
315
316 acct = cur;
317 break;
318 }
319err:
320 rcu_read_unlock();
321 return acct;
322}
323EXPORT_SYMBOL_GPL(nfnl_acct_find_get);
324
325void nfnl_acct_put(struct nf_acct *acct)
326{
327 atomic_dec(&acct->refcnt);
328 module_put(THIS_MODULE);
329}
330EXPORT_SYMBOL_GPL(nfnl_acct_put);
331
332void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct)
333{
334 atomic64_inc(&nfacct->pkts);
335 atomic64_add(skb->len, &nfacct->bytes);
336}
337EXPORT_SYMBOL_GPL(nfnl_acct_update);
338
339static int __init nfnl_acct_init(void)
340{
341 int ret;
342
343 pr_info("nfnl_acct: registering with nfnetlink.\n");
344 ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
345 if (ret < 0) {
346 pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
347 goto err_out;
348 }
349 return 0;
350err_out:
351 return ret;
352}
353
354static void __exit nfnl_acct_exit(void)
355{
356 struct nf_acct *cur, *tmp;
357
358 pr_info("nfnl_acct: unregistering from nfnetlink.\n");
359 nfnetlink_subsys_unregister(&nfnl_acct_subsys);
360
361 list_for_each_entry_safe(cur, tmp, &nfnl_acct_list, head) {
362 list_del_rcu(&cur->head);
363
364
365 kfree_rcu(cur, rcu_head);
366 }
367}
368
369module_init(nfnl_acct_init);
370module_exit(nfnl_acct_exit);
371
