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9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/skbuff.h>
13#include <linux/netlink.h>
14#include <linux/rculist.h>
15#include <linux/slab.h>
16#include <linux/types.h>
17#include <linux/errno.h>
18#include <net/netlink.h>
19#include <net/sock.h>
20#include <asm/atomic.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
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_u64(tb[NFACCT_BYTES])));
83 }
84 if (tb[NFACCT_PKTS]) {
85 atomic64_set(&nfacct->pkts,
86 be64_to_cpu(nla_get_u64(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 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
112 NLA_PUT_STRING(skb, NFACCT_NAME, acct->name);
113
114 if (type == NFNL_MSG_ACCT_GET_CTRZERO) {
115 pkts = atomic64_xchg(&acct->pkts, 0);
116 bytes = atomic64_xchg(&acct->bytes, 0);
117 } else {
118 pkts = atomic64_read(&acct->pkts);
119 bytes = atomic64_read(&acct->bytes);
120 }
121 NLA_PUT_BE64(skb, NFACCT_PKTS, cpu_to_be64(pkts));
122 NLA_PUT_BE64(skb, NFACCT_BYTES, cpu_to_be64(bytes));
123 NLA_PUT_BE32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt)));
124
125 nlmsg_end(skb, nlh);
126 return skb->len;
127
128nlmsg_failure:
129nla_put_failure:
130 nlmsg_cancel(skb, nlh);
131 return -1;
132}
133
134static int
135nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
136{
137 struct nf_acct *cur, *last;
138
139 if (cb->args[2])
140 return 0;
141
142 last = (struct nf_acct *)cb->args[1];
143 if (cb->args[1])
144 cb->args[1] = 0;
145
146 rcu_read_lock();
147 list_for_each_entry_rcu(cur, &nfnl_acct_list, head) {
148 if (last && cur != last)
149 continue;
150
151 if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).pid,
152 cb->nlh->nlmsg_seq,
153 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
154 NFNL_MSG_ACCT_NEW, cur) < 0) {
155 cb->args[1] = (unsigned long)cur;
156 break;
157 }
158 }
159 if (!cb->args[1])
160 cb->args[2] = 1;
161 rcu_read_unlock();
162 return skb->len;
163}
164
165static int
166nfnl_acct_get(struct sock *nfnl, struct sk_buff *skb,
167 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
168{
169 int ret = -ENOENT;
170 struct nf_acct *cur;
171 char *acct_name;
172
173 if (nlh->nlmsg_flags & NLM_F_DUMP) {
174 return netlink_dump_start(nfnl, skb, nlh, nfnl_acct_dump,
175 NULL, 0);
176 }
177
178 if (!tb[NFACCT_NAME])
179 return -EINVAL;
180 acct_name = nla_data(tb[NFACCT_NAME]);
181
182 list_for_each_entry(cur, &nfnl_acct_list, head) {
183 struct sk_buff *skb2;
184
185 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
186 continue;
187
188 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
189 if (skb2 == NULL) {
190 ret = -ENOMEM;
191 break;
192 }
193
194 ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).pid,
195 nlh->nlmsg_seq,
196 NFNL_MSG_TYPE(nlh->nlmsg_type),
197 NFNL_MSG_ACCT_NEW, cur);
198 if (ret <= 0) {
199 kfree_skb(skb2);
200 break;
201 }
202 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).pid,
203 MSG_DONTWAIT);
204 if (ret > 0)
205 ret = 0;
206
207
208 return ret == -EAGAIN ? -ENOBUFS : ret;
209 }
210 return ret;
211}
212
213
214static int nfnl_acct_try_del(struct nf_acct *cur)
215{
216 int ret = 0;
217
218
219 if (atomic_dec_and_test(&cur->refcnt)) {
220
221 list_del_rcu(&cur->head);
222 kfree_rcu(cur, rcu_head);
223 } else {
224
225 atomic_inc(&cur->refcnt);
226 ret = -EBUSY;
227 }
228 return ret;
229}
230
231static int
232nfnl_acct_del(struct sock *nfnl, struct sk_buff *skb,
233 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
234{
235 char *acct_name;
236 struct nf_acct *cur;
237 int ret = -ENOENT;
238
239 if (!tb[NFACCT_NAME]) {
240 list_for_each_entry(cur, &nfnl_acct_list, head)
241 nfnl_acct_try_del(cur);
242
243 return 0;
244 }
245 acct_name = nla_data(tb[NFACCT_NAME]);
246
247 list_for_each_entry(cur, &nfnl_acct_list, head) {
248 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0)
249 continue;
250
251 ret = nfnl_acct_try_del(cur);
252 if (ret < 0)
253 return ret;
254
255 break;
256 }
257 return ret;
258}
259
260static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
261 [NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
262 [NFACCT_BYTES] = { .type = NLA_U64 },
263 [NFACCT_PKTS] = { .type = NLA_U64 },
264};
265
266static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
267 [NFNL_MSG_ACCT_NEW] = { .call = nfnl_acct_new,
268 .attr_count = NFACCT_MAX,
269 .policy = nfnl_acct_policy },
270 [NFNL_MSG_ACCT_GET] = { .call = nfnl_acct_get,
271 .attr_count = NFACCT_MAX,
272 .policy = nfnl_acct_policy },
273 [NFNL_MSG_ACCT_GET_CTRZERO] = { .call = nfnl_acct_get,
274 .attr_count = NFACCT_MAX,
275 .policy = nfnl_acct_policy },
276 [NFNL_MSG_ACCT_DEL] = { .call = nfnl_acct_del,
277 .attr_count = NFACCT_MAX,
278 .policy = nfnl_acct_policy },
279};
280
281static const struct nfnetlink_subsystem nfnl_acct_subsys = {
282 .name = "acct",
283 .subsys_id = NFNL_SUBSYS_ACCT,
284 .cb_count = NFNL_MSG_ACCT_MAX,
285 .cb = nfnl_acct_cb,
286};
287
288MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);
289
290struct nf_acct *nfnl_acct_find_get(const char *acct_name)
291{
292 struct nf_acct *cur, *acct = NULL;
293
294 rcu_read_lock();
295 list_for_each_entry_rcu(cur, &nfnl_acct_list, head) {
296 if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
297 continue;
298
299 if (!try_module_get(THIS_MODULE))
300 goto err;
301
302 if (!atomic_inc_not_zero(&cur->refcnt)) {
303 module_put(THIS_MODULE);
304 goto err;
305 }
306
307 acct = cur;
308 break;
309 }
310err:
311 rcu_read_unlock();
312 return acct;
313}
314EXPORT_SYMBOL_GPL(nfnl_acct_find_get);
315
316void nfnl_acct_put(struct nf_acct *acct)
317{
318 atomic_dec(&acct->refcnt);
319 module_put(THIS_MODULE);
320}
321EXPORT_SYMBOL_GPL(nfnl_acct_put);
322
323void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct)
324{
325 atomic64_inc(&nfacct->pkts);
326 atomic64_add(skb->len, &nfacct->bytes);
327}
328EXPORT_SYMBOL_GPL(nfnl_acct_update);
329
330static int __init nfnl_acct_init(void)
331{
332 int ret;
333
334 pr_info("nfnl_acct: registering with nfnetlink.\n");
335 ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
336 if (ret < 0) {
337 pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
338 goto err_out;
339 }
340 return 0;
341err_out:
342 return ret;
343}
344
345static void __exit nfnl_acct_exit(void)
346{
347 struct nf_acct *cur, *tmp;
348
349 pr_info("nfnl_acct: unregistering from nfnetlink.\n");
350 nfnetlink_subsys_unregister(&nfnl_acct_subsys);
351
352 list_for_each_entry_safe(cur, tmp, &nfnl_acct_list, head) {
353 list_del_rcu(&cur->head);
354
355
356 kfree_rcu(cur, rcu_head);
357 }
358}
359
360module_init(nfnl_acct_init);
361module_exit(nfnl_acct_exit);
362
