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17#include <linux/module.h>
18#include <linux/types.h>
19#include <linux/socket.h>
20#include <linux/kernel.h>
21#include <linux/string.h>
22#include <linux/sockios.h>
23#include <linux/net.h>
24#include <linux/skbuff.h>
25#include <asm/uaccess.h>
26#include <net/sock.h>
27#include <linux/init.h>
28
29#include <net/netlink.h>
30#include <linux/netfilter/nfnetlink.h>
31
32MODULE_LICENSE("GPL");
33MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
34MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
35
36static char __initdata nfversion[] = "0.30";
37
38static struct {
39 struct mutex mutex;
40 const struct nfnetlink_subsystem __rcu *subsys;
41} table[NFNL_SUBSYS_COUNT];
42
43static const int nfnl_group2type[NFNLGRP_MAX+1] = {
44 [NFNLGRP_CONNTRACK_NEW] = NFNL_SUBSYS_CTNETLINK,
45 [NFNLGRP_CONNTRACK_UPDATE] = NFNL_SUBSYS_CTNETLINK,
46 [NFNLGRP_CONNTRACK_DESTROY] = NFNL_SUBSYS_CTNETLINK,
47 [NFNLGRP_CONNTRACK_EXP_NEW] = NFNL_SUBSYS_CTNETLINK_EXP,
48 [NFNLGRP_CONNTRACK_EXP_UPDATE] = NFNL_SUBSYS_CTNETLINK_EXP,
49 [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
50 [NFNLGRP_NFTABLES] = NFNL_SUBSYS_NFTABLES,
51 [NFNLGRP_ACCT_QUOTA] = NFNL_SUBSYS_ACCT,
52};
53
54void nfnl_lock(__u8 subsys_id)
55{
56 mutex_lock(&table[subsys_id].mutex);
57}
58EXPORT_SYMBOL_GPL(nfnl_lock);
59
60void nfnl_unlock(__u8 subsys_id)
61{
62 mutex_unlock(&table[subsys_id].mutex);
63}
64EXPORT_SYMBOL_GPL(nfnl_unlock);
65
66#ifdef CONFIG_PROVE_LOCKING
67int lockdep_nfnl_is_held(u8 subsys_id)
68{
69 return lockdep_is_held(&table[subsys_id].mutex);
70}
71EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
72#endif
73
74int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
75{
76 nfnl_lock(n->subsys_id);
77 if (table[n->subsys_id].subsys) {
78 nfnl_unlock(n->subsys_id);
79 return -EBUSY;
80 }
81 rcu_assign_pointer(table[n->subsys_id].subsys, n);
82 nfnl_unlock(n->subsys_id);
83
84 return 0;
85}
86EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
87
88int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
89{
90 nfnl_lock(n->subsys_id);
91 table[n->subsys_id].subsys = NULL;
92 nfnl_unlock(n->subsys_id);
93 synchronize_rcu();
94 return 0;
95}
96EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
97
98static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u_int16_t type)
99{
100 u_int8_t subsys_id = NFNL_SUBSYS_ID(type);
101
102 if (subsys_id >= NFNL_SUBSYS_COUNT)
103 return NULL;
104
105 return rcu_dereference(table[subsys_id].subsys);
106}
107
108static inline const struct nfnl_callback *
109nfnetlink_find_client(u_int16_t type, const struct nfnetlink_subsystem *ss)
110{
111 u_int8_t cb_id = NFNL_MSG_TYPE(type);
112
113 if (cb_id >= ss->cb_count)
114 return NULL;
115
116 return &ss->cb[cb_id];
117}
118
119int nfnetlink_has_listeners(struct net *net, unsigned int group)
120{
121 return netlink_has_listeners(net->nfnl, group);
122}
123EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
124
125struct sk_buff *nfnetlink_alloc_skb(struct net *net, unsigned int size,
126 u32 dst_portid, gfp_t gfp_mask)
127{
128 return netlink_alloc_skb(net->nfnl, size, dst_portid, gfp_mask);
129}
130EXPORT_SYMBOL_GPL(nfnetlink_alloc_skb);
131
132int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
133 unsigned int group, int echo, gfp_t flags)
134{
135 return nlmsg_notify(net->nfnl, skb, portid, group, echo, flags);
136}
137EXPORT_SYMBOL_GPL(nfnetlink_send);
138
139int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
140{
141 return netlink_set_err(net->nfnl, portid, group, error);
142}
143EXPORT_SYMBOL_GPL(nfnetlink_set_err);
144
145int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid,
146 int flags)
147{
148 return netlink_unicast(net->nfnl, skb, portid, flags);
149}
150EXPORT_SYMBOL_GPL(nfnetlink_unicast);
151
152
153static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
154{
155 struct net *net = sock_net(skb->sk);
156 const struct nfnl_callback *nc;
157 const struct nfnetlink_subsystem *ss;
158 int type, err;
159
160
161 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
162 return 0;
163
164 type = nlh->nlmsg_type;
165replay:
166 rcu_read_lock();
167 ss = nfnetlink_get_subsys(type);
168 if (!ss) {
169#ifdef CONFIG_MODULES
170 rcu_read_unlock();
171 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
172 rcu_read_lock();
173 ss = nfnetlink_get_subsys(type);
174 if (!ss)
175#endif
176 {
177 rcu_read_unlock();
178 return -EINVAL;
179 }
180 }
181
182 nc = nfnetlink_find_client(type, ss);
183 if (!nc) {
184 rcu_read_unlock();
185 return -EINVAL;
186 }
187
188 {
189 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
190 u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
191 struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
192 struct nlattr *attr = (void *)nlh + min_len;
193 int attrlen = nlh->nlmsg_len - min_len;
194 __u8 subsys_id = NFNL_SUBSYS_ID(type);
195
196 err = nla_parse(cda, ss->cb[cb_id].attr_count,
197 attr, attrlen, ss->cb[cb_id].policy);
198 if (err < 0) {
199 rcu_read_unlock();
200 return err;
201 }
202
203 if (nc->call_rcu) {
204 err = nc->call_rcu(net->nfnl, skb, nlh,
205 (const struct nlattr **)cda);
206 rcu_read_unlock();
207 } else {
208 rcu_read_unlock();
209 nfnl_lock(subsys_id);
210 if (rcu_dereference_protected(table[subsys_id].subsys,
211 lockdep_is_held(&table[subsys_id].mutex)) != ss ||
212 nfnetlink_find_client(type, ss) != nc)
213 err = -EAGAIN;
214 else if (nc->call)
215 err = nc->call(net->nfnl, skb, nlh,
216 (const struct nlattr **)cda);
217 else
218 err = -EINVAL;
219 nfnl_unlock(subsys_id);
220 }
221 if (err == -EAGAIN)
222 goto replay;
223 return err;
224 }
225}
226
227struct nfnl_err {
228 struct list_head head;
229 struct nlmsghdr *nlh;
230 int err;
231};
232
233static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err)
234{
235 struct nfnl_err *nfnl_err;
236
237 nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
238 if (nfnl_err == NULL)
239 return -ENOMEM;
240
241 nfnl_err->nlh = nlh;
242 nfnl_err->err = err;
243 list_add_tail(&nfnl_err->head, list);
244
245 return 0;
246}
247
248static void nfnl_err_del(struct nfnl_err *nfnl_err)
249{
250 list_del(&nfnl_err->head);
251 kfree(nfnl_err);
252}
253
254static void nfnl_err_reset(struct list_head *err_list)
255{
256 struct nfnl_err *nfnl_err, *next;
257
258 list_for_each_entry_safe(nfnl_err, next, err_list, head)
259 nfnl_err_del(nfnl_err);
260}
261
262static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
263{
264 struct nfnl_err *nfnl_err, *next;
265
266 list_for_each_entry_safe(nfnl_err, next, err_list, head) {
267 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err);
268 nfnl_err_del(nfnl_err);
269 }
270}
271
272static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
273 u_int16_t subsys_id)
274{
275 struct sk_buff *oskb = skb;
276 struct net *net = sock_net(skb->sk);
277 const struct nfnetlink_subsystem *ss;
278 const struct nfnl_callback *nc;
279 bool success = true, done = false;
280 static LIST_HEAD(err_list);
281 int err;
282
283 if (subsys_id >= NFNL_SUBSYS_COUNT)
284 return netlink_ack(skb, nlh, -EINVAL);
285replay:
286 skb = netlink_skb_clone(oskb, GFP_KERNEL);
287 if (!skb)
288 return netlink_ack(oskb, nlh, -ENOMEM);
289
290 skb->sk = oskb->sk;
291
292 nfnl_lock(subsys_id);
293 ss = rcu_dereference_protected(table[subsys_id].subsys,
294 lockdep_is_held(&table[subsys_id].mutex));
295 if (!ss) {
296#ifdef CONFIG_MODULES
297 nfnl_unlock(subsys_id);
298 request_module("nfnetlink-subsys-%d", subsys_id);
299 nfnl_lock(subsys_id);
300 ss = rcu_dereference_protected(table[subsys_id].subsys,
301 lockdep_is_held(&table[subsys_id].mutex));
302 if (!ss)
303#endif
304 {
305 nfnl_unlock(subsys_id);
306 netlink_ack(skb, nlh, -EOPNOTSUPP);
307 return kfree_skb(skb);
308 }
309 }
310
311 if (!ss->commit || !ss->abort) {
312 nfnl_unlock(subsys_id);
313 netlink_ack(skb, nlh, -EOPNOTSUPP);
314 return kfree_skb(skb);
315 }
316
317 while (skb->len >= nlmsg_total_size(0)) {
318 int msglen, type;
319
320 nlh = nlmsg_hdr(skb);
321 err = 0;
322
323 if (nlmsg_len(nlh) < sizeof(struct nfgenmsg) ||
324 skb->len < nlh->nlmsg_len) {
325 err = -EINVAL;
326 goto ack;
327 }
328
329
330 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
331 err = -EINVAL;
332 goto ack;
333 }
334
335 type = nlh->nlmsg_type;
336 if (type == NFNL_MSG_BATCH_BEGIN) {
337
338 nfnl_err_reset(&err_list);
339 success = false;
340 goto done;
341 } else if (type == NFNL_MSG_BATCH_END) {
342 done = true;
343 goto done;
344 } else if (type < NLMSG_MIN_TYPE) {
345 err = -EINVAL;
346 goto ack;
347 }
348
349
350
351
352 if (NFNL_SUBSYS_ID(type) != subsys_id) {
353 err = -EINVAL;
354 goto ack;
355 }
356
357 nc = nfnetlink_find_client(type, ss);
358 if (!nc) {
359 err = -EINVAL;
360 goto ack;
361 }
362
363 {
364 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
365 u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
366 struct nlattr *cda[ss->cb[cb_id].attr_count + 1];
367 struct nlattr *attr = (void *)nlh + min_len;
368 int attrlen = nlh->nlmsg_len - min_len;
369
370 err = nla_parse(cda, ss->cb[cb_id].attr_count,
371 attr, attrlen, ss->cb[cb_id].policy);
372 if (err < 0)
373 goto ack;
374
375 if (nc->call_batch) {
376 err = nc->call_batch(net->nfnl, skb, nlh,
377 (const struct nlattr **)cda);
378 }
379
380
381
382
383
384 if (err == -EAGAIN) {
385 nfnl_err_reset(&err_list);
386 ss->abort(oskb);
387 nfnl_unlock(subsys_id);
388 kfree_skb(skb);
389 goto replay;
390 }
391 }
392ack:
393 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
394
395
396
397
398 if (nfnl_err_add(&err_list, nlh, err) < 0) {
399
400
401
402
403 nfnl_err_reset(&err_list);
404 netlink_ack(skb, nlmsg_hdr(oskb), -ENOMEM);
405 success = false;
406 goto done;
407 }
408
409
410
411
412 if (err)
413 success = false;
414 }
415
416 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
417 if (msglen > skb->len)
418 msglen = skb->len;
419 skb_pull(skb, msglen);
420 }
421done:
422 if (success && done)
423 ss->commit(oskb);
424 else
425 ss->abort(oskb);
426
427 nfnl_err_deliver(&err_list, oskb);
428 nfnl_unlock(subsys_id);
429 kfree_skb(skb);
430}
431
432static void nfnetlink_rcv(struct sk_buff *skb)
433{
434 struct nlmsghdr *nlh = nlmsg_hdr(skb);
435 int msglen;
436
437 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
438 skb->len < nlh->nlmsg_len)
439 return;
440
441 if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
442 netlink_ack(skb, nlh, -EPERM);
443 return;
444 }
445
446 if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN) {
447 struct nfgenmsg *nfgenmsg;
448
449 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
450 if (msglen > skb->len)
451 msglen = skb->len;
452
453 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
454 skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
455 return;
456
457 nfgenmsg = nlmsg_data(nlh);
458 skb_pull(skb, msglen);
459 nfnetlink_rcv_batch(skb, nlh, nfgenmsg->res_id);
460 } else {
461 netlink_rcv_skb(skb, &nfnetlink_rcv_msg);
462 }
463}
464
465#ifdef CONFIG_MODULES
466static int nfnetlink_bind(struct net *net, int group)
467{
468 const struct nfnetlink_subsystem *ss;
469 int type;
470
471 if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
472 return 0;
473
474 type = nfnl_group2type[group];
475
476 rcu_read_lock();
477 ss = nfnetlink_get_subsys(type);
478 rcu_read_unlock();
479 if (!ss)
480 request_module("nfnetlink-subsys-%d", type);
481 return 0;
482}
483#endif
484
485static int __net_init nfnetlink_net_init(struct net *net)
486{
487 struct sock *nfnl;
488 struct netlink_kernel_cfg cfg = {
489 .groups = NFNLGRP_MAX,
490 .input = nfnetlink_rcv,
491#ifdef CONFIG_MODULES
492 .bind = nfnetlink_bind,
493#endif
494 };
495
496 nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
497 if (!nfnl)
498 return -ENOMEM;
499 net->nfnl_stash = nfnl;
500 rcu_assign_pointer(net->nfnl, nfnl);
501 return 0;
502}
503
504static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
505{
506 struct net *net;
507
508 list_for_each_entry(net, net_exit_list, exit_list)
509 RCU_INIT_POINTER(net->nfnl, NULL);
510 synchronize_net();
511 list_for_each_entry(net, net_exit_list, exit_list)
512 netlink_kernel_release(net->nfnl_stash);
513}
514
515static struct pernet_operations nfnetlink_net_ops = {
516 .init = nfnetlink_net_init,
517 .exit_batch = nfnetlink_net_exit_batch,
518};
519
520static int __init nfnetlink_init(void)
521{
522 int i;
523
524 for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
525 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
526
527 for (i=0; i<NFNL_SUBSYS_COUNT; i++)
528 mutex_init(&table[i].mutex);
529
530 pr_info("Netfilter messages via NETLINK v%s.\n", nfversion);
531 return register_pernet_subsys(&nfnetlink_net_ops);
532}
533
534static void __exit nfnetlink_exit(void)
535{
536 pr_info("Removing netfilter NETLINK layer.\n");
537 unregister_pernet_subsys(&nfnetlink_net_ops);
538}
539module_init(nfnetlink_init);
540module_exit(nfnetlink_exit);
541
