perf probe: Add --bootconfig to output definition in bootconfig format
[linux-2.6-microblaze.git] / net / netfilter / nfnetlink.c
1 /* Netfilter messages via netlink socket. Allows for user space
2  * protocol helpers and general trouble making from userspace.
3  *
4  * (C) 2001 by Jay Schulist <jschlst@samba.org>,
5  * (C) 2002-2005 by Harald Welte <laforge@gnumonks.org>
6  * (C) 2005-2017 by Pablo Neira Ayuso <pablo@netfilter.org>
7  *
8  * Initial netfilter messages via netlink development funded and
9  * generally made possible by Network Robots, Inc. (www.networkrobots.com)
10  *
11  * Further development of this code funded by Astaro AG (http://www.astaro.com)
12  *
13  * This software may be used and distributed according to the terms
14  * of the GNU General Public License, incorporated herein by reference.
15  */
16
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 <linux/uaccess.h>
26 #include <net/sock.h>
27 #include <linux/init.h>
28 #include <linux/sched/signal.h>
29
30 #include <net/netlink.h>
31 #include <net/netns/generic.h>
32 #include <linux/netfilter/nfnetlink.h>
33
34 MODULE_LICENSE("GPL");
35 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
36 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER);
37 MODULE_DESCRIPTION("Netfilter messages via netlink socket");
38
39 #define nfnl_dereference_protected(id) \
40         rcu_dereference_protected(table[(id)].subsys, \
41                                   lockdep_nfnl_is_held((id)))
42
43 #define NFNL_MAX_ATTR_COUNT     32
44
45 static unsigned int nfnetlink_pernet_id __read_mostly;
46
47 struct nfnl_net {
48         struct sock *nfnl;
49 };
50
51 static struct {
52         struct mutex                            mutex;
53         const struct nfnetlink_subsystem __rcu  *subsys;
54 } table[NFNL_SUBSYS_COUNT];
55
56 static struct lock_class_key nfnl_lockdep_keys[NFNL_SUBSYS_COUNT];
57
58 static const char *const nfnl_lockdep_names[NFNL_SUBSYS_COUNT] = {
59         [NFNL_SUBSYS_NONE] = "nfnl_subsys_none",
60         [NFNL_SUBSYS_CTNETLINK] = "nfnl_subsys_ctnetlink",
61         [NFNL_SUBSYS_CTNETLINK_EXP] = "nfnl_subsys_ctnetlink_exp",
62         [NFNL_SUBSYS_QUEUE] = "nfnl_subsys_queue",
63         [NFNL_SUBSYS_ULOG] = "nfnl_subsys_ulog",
64         [NFNL_SUBSYS_OSF] = "nfnl_subsys_osf",
65         [NFNL_SUBSYS_IPSET] = "nfnl_subsys_ipset",
66         [NFNL_SUBSYS_ACCT] = "nfnl_subsys_acct",
67         [NFNL_SUBSYS_CTNETLINK_TIMEOUT] = "nfnl_subsys_cttimeout",
68         [NFNL_SUBSYS_CTHELPER] = "nfnl_subsys_cthelper",
69         [NFNL_SUBSYS_NFTABLES] = "nfnl_subsys_nftables",
70         [NFNL_SUBSYS_NFT_COMPAT] = "nfnl_subsys_nftcompat",
71 };
72
73 static const int nfnl_group2type[NFNLGRP_MAX+1] = {
74         [NFNLGRP_CONNTRACK_NEW]         = NFNL_SUBSYS_CTNETLINK,
75         [NFNLGRP_CONNTRACK_UPDATE]      = NFNL_SUBSYS_CTNETLINK,
76         [NFNLGRP_CONNTRACK_DESTROY]     = NFNL_SUBSYS_CTNETLINK,
77         [NFNLGRP_CONNTRACK_EXP_NEW]     = NFNL_SUBSYS_CTNETLINK_EXP,
78         [NFNLGRP_CONNTRACK_EXP_UPDATE]  = NFNL_SUBSYS_CTNETLINK_EXP,
79         [NFNLGRP_CONNTRACK_EXP_DESTROY] = NFNL_SUBSYS_CTNETLINK_EXP,
80         [NFNLGRP_NFTABLES]              = NFNL_SUBSYS_NFTABLES,
81         [NFNLGRP_ACCT_QUOTA]            = NFNL_SUBSYS_ACCT,
82         [NFNLGRP_NFTRACE]               = NFNL_SUBSYS_NFTABLES,
83 };
84
85 static struct nfnl_net *nfnl_pernet(struct net *net)
86 {
87         return net_generic(net, nfnetlink_pernet_id);
88 }
89
90 void nfnl_lock(__u8 subsys_id)
91 {
92         mutex_lock(&table[subsys_id].mutex);
93 }
94 EXPORT_SYMBOL_GPL(nfnl_lock);
95
96 void nfnl_unlock(__u8 subsys_id)
97 {
98         mutex_unlock(&table[subsys_id].mutex);
99 }
100 EXPORT_SYMBOL_GPL(nfnl_unlock);
101
102 #ifdef CONFIG_PROVE_LOCKING
103 bool lockdep_nfnl_is_held(u8 subsys_id)
104 {
105         return lockdep_is_held(&table[subsys_id].mutex);
106 }
107 EXPORT_SYMBOL_GPL(lockdep_nfnl_is_held);
108 #endif
109
110 int nfnetlink_subsys_register(const struct nfnetlink_subsystem *n)
111 {
112         u8 cb_id;
113
114         /* Sanity-check attr_count size to avoid stack buffer overflow. */
115         for (cb_id = 0; cb_id < n->cb_count; cb_id++)
116                 if (WARN_ON(n->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT))
117                         return -EINVAL;
118
119         nfnl_lock(n->subsys_id);
120         if (table[n->subsys_id].subsys) {
121                 nfnl_unlock(n->subsys_id);
122                 return -EBUSY;
123         }
124         rcu_assign_pointer(table[n->subsys_id].subsys, n);
125         nfnl_unlock(n->subsys_id);
126
127         return 0;
128 }
129 EXPORT_SYMBOL_GPL(nfnetlink_subsys_register);
130
131 int nfnetlink_subsys_unregister(const struct nfnetlink_subsystem *n)
132 {
133         nfnl_lock(n->subsys_id);
134         table[n->subsys_id].subsys = NULL;
135         nfnl_unlock(n->subsys_id);
136         synchronize_rcu();
137         return 0;
138 }
139 EXPORT_SYMBOL_GPL(nfnetlink_subsys_unregister);
140
141 static inline const struct nfnetlink_subsystem *nfnetlink_get_subsys(u16 type)
142 {
143         u8 subsys_id = NFNL_SUBSYS_ID(type);
144
145         if (subsys_id >= NFNL_SUBSYS_COUNT)
146                 return NULL;
147
148         return rcu_dereference(table[subsys_id].subsys);
149 }
150
151 static inline const struct nfnl_callback *
152 nfnetlink_find_client(u16 type, const struct nfnetlink_subsystem *ss)
153 {
154         u8 cb_id = NFNL_MSG_TYPE(type);
155
156         if (cb_id >= ss->cb_count)
157                 return NULL;
158
159         return &ss->cb[cb_id];
160 }
161
162 int nfnetlink_has_listeners(struct net *net, unsigned int group)
163 {
164         struct nfnl_net *nfnlnet = nfnl_pernet(net);
165
166         return netlink_has_listeners(nfnlnet->nfnl, group);
167 }
168 EXPORT_SYMBOL_GPL(nfnetlink_has_listeners);
169
170 int nfnetlink_send(struct sk_buff *skb, struct net *net, u32 portid,
171                    unsigned int group, int echo, gfp_t flags)
172 {
173         struct nfnl_net *nfnlnet = nfnl_pernet(net);
174
175         return nlmsg_notify(nfnlnet->nfnl, skb, portid, group, echo, flags);
176 }
177 EXPORT_SYMBOL_GPL(nfnetlink_send);
178
179 int nfnetlink_set_err(struct net *net, u32 portid, u32 group, int error)
180 {
181         struct nfnl_net *nfnlnet = nfnl_pernet(net);
182
183         return netlink_set_err(nfnlnet->nfnl, portid, group, error);
184 }
185 EXPORT_SYMBOL_GPL(nfnetlink_set_err);
186
187 int nfnetlink_unicast(struct sk_buff *skb, struct net *net, u32 portid)
188 {
189         struct nfnl_net *nfnlnet = nfnl_pernet(net);
190         int err;
191
192         err = nlmsg_unicast(nfnlnet->nfnl, skb, portid);
193         if (err == -EAGAIN)
194                 err = -ENOBUFS;
195
196         return err;
197 }
198 EXPORT_SYMBOL_GPL(nfnetlink_unicast);
199
200 void nfnetlink_broadcast(struct net *net, struct sk_buff *skb, __u32 portid,
201                          __u32 group, gfp_t allocation)
202 {
203         struct nfnl_net *nfnlnet = nfnl_pernet(net);
204
205         netlink_broadcast(nfnlnet->nfnl, skb, portid, group, allocation);
206 }
207 EXPORT_SYMBOL_GPL(nfnetlink_broadcast);
208
209 /* Process one complete nfnetlink message. */
210 static int nfnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
211                              struct netlink_ext_ack *extack)
212 {
213         struct net *net = sock_net(skb->sk);
214         const struct nfnl_callback *nc;
215         const struct nfnetlink_subsystem *ss;
216         int type, err;
217
218         /* All the messages must at least contain nfgenmsg */
219         if (nlmsg_len(nlh) < sizeof(struct nfgenmsg))
220                 return 0;
221
222         type = nlh->nlmsg_type;
223 replay:
224         rcu_read_lock();
225
226         ss = nfnetlink_get_subsys(type);
227         if (!ss) {
228 #ifdef CONFIG_MODULES
229                 rcu_read_unlock();
230                 request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
231                 rcu_read_lock();
232                 ss = nfnetlink_get_subsys(type);
233                 if (!ss)
234 #endif
235                 {
236                         rcu_read_unlock();
237                         return -EINVAL;
238                 }
239         }
240
241         nc = nfnetlink_find_client(type, ss);
242         if (!nc) {
243                 rcu_read_unlock();
244                 return -EINVAL;
245         }
246
247         {
248                 int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
249                 struct nfnl_net *nfnlnet = nfnl_pernet(net);
250                 u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
251                 struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
252                 struct nlattr *attr = (void *)nlh + min_len;
253                 int attrlen = nlh->nlmsg_len - min_len;
254                 __u8 subsys_id = NFNL_SUBSYS_ID(type);
255                 struct nfnl_info info = {
256                         .net    = net,
257                         .sk     = nfnlnet->nfnl,
258                         .nlh    = nlh,
259                         .extack = extack,
260                 };
261
262                 /* Sanity-check NFNL_MAX_ATTR_COUNT */
263                 if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
264                         rcu_read_unlock();
265                         return -ENOMEM;
266                 }
267
268                 err = nla_parse_deprecated(cda, ss->cb[cb_id].attr_count,
269                                            attr, attrlen,
270                                            ss->cb[cb_id].policy, extack);
271                 if (err < 0) {
272                         rcu_read_unlock();
273                         return err;
274                 }
275
276                 if (!nc->call) {
277                         rcu_read_unlock();
278                         return -EINVAL;
279                 }
280
281                 switch (nc->type) {
282                 case NFNL_CB_RCU:
283                         err = nc->call(skb, &info, (const struct nlattr **)cda);
284                         rcu_read_unlock();
285                         break;
286                 case NFNL_CB_MUTEX:
287                         rcu_read_unlock();
288                         nfnl_lock(subsys_id);
289                         if (nfnl_dereference_protected(subsys_id) != ss ||
290                             nfnetlink_find_client(type, ss) != nc) {
291                                 err = -EAGAIN;
292                                 break;
293                         }
294                         err = nc->call(skb, &info, (const struct nlattr **)cda);
295                         nfnl_unlock(subsys_id);
296                         break;
297                 default:
298                         rcu_read_unlock();
299                         err = -EINVAL;
300                         break;
301                 }
302                 if (err == -EAGAIN)
303                         goto replay;
304                 return err;
305         }
306 }
307
308 struct nfnl_err {
309         struct list_head        head;
310         struct nlmsghdr         *nlh;
311         int                     err;
312         struct netlink_ext_ack  extack;
313 };
314
315 static int nfnl_err_add(struct list_head *list, struct nlmsghdr *nlh, int err,
316                         const struct netlink_ext_ack *extack)
317 {
318         struct nfnl_err *nfnl_err;
319
320         nfnl_err = kmalloc(sizeof(struct nfnl_err), GFP_KERNEL);
321         if (nfnl_err == NULL)
322                 return -ENOMEM;
323
324         nfnl_err->nlh = nlh;
325         nfnl_err->err = err;
326         nfnl_err->extack = *extack;
327         list_add_tail(&nfnl_err->head, list);
328
329         return 0;
330 }
331
332 static void nfnl_err_del(struct nfnl_err *nfnl_err)
333 {
334         list_del(&nfnl_err->head);
335         kfree(nfnl_err);
336 }
337
338 static void nfnl_err_reset(struct list_head *err_list)
339 {
340         struct nfnl_err *nfnl_err, *next;
341
342         list_for_each_entry_safe(nfnl_err, next, err_list, head)
343                 nfnl_err_del(nfnl_err);
344 }
345
346 static void nfnl_err_deliver(struct list_head *err_list, struct sk_buff *skb)
347 {
348         struct nfnl_err *nfnl_err, *next;
349
350         list_for_each_entry_safe(nfnl_err, next, err_list, head) {
351                 netlink_ack(skb, nfnl_err->nlh, nfnl_err->err,
352                             &nfnl_err->extack);
353                 nfnl_err_del(nfnl_err);
354         }
355 }
356
357 enum {
358         NFNL_BATCH_FAILURE      = (1 << 0),
359         NFNL_BATCH_DONE         = (1 << 1),
360         NFNL_BATCH_REPLAY       = (1 << 2),
361 };
362
363 static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
364                                 u16 subsys_id, u32 genid)
365 {
366         struct sk_buff *oskb = skb;
367         struct net *net = sock_net(skb->sk);
368         const struct nfnetlink_subsystem *ss;
369         const struct nfnl_callback *nc;
370         struct netlink_ext_ack extack;
371         LIST_HEAD(err_list);
372         u32 status;
373         int err;
374
375         if (subsys_id >= NFNL_SUBSYS_COUNT)
376                 return netlink_ack(skb, nlh, -EINVAL, NULL);
377 replay:
378         status = 0;
379 replay_abort:
380         skb = netlink_skb_clone(oskb, GFP_KERNEL);
381         if (!skb)
382                 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
383
384         nfnl_lock(subsys_id);
385         ss = nfnl_dereference_protected(subsys_id);
386         if (!ss) {
387 #ifdef CONFIG_MODULES
388                 nfnl_unlock(subsys_id);
389                 request_module("nfnetlink-subsys-%d", subsys_id);
390                 nfnl_lock(subsys_id);
391                 ss = nfnl_dereference_protected(subsys_id);
392                 if (!ss)
393 #endif
394                 {
395                         nfnl_unlock(subsys_id);
396                         netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
397                         return kfree_skb(skb);
398                 }
399         }
400
401         if (!ss->valid_genid || !ss->commit || !ss->abort) {
402                 nfnl_unlock(subsys_id);
403                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
404                 return kfree_skb(skb);
405         }
406
407         if (!try_module_get(ss->owner)) {
408                 nfnl_unlock(subsys_id);
409                 netlink_ack(oskb, nlh, -EOPNOTSUPP, NULL);
410                 return kfree_skb(skb);
411         }
412
413         if (!ss->valid_genid(net, genid)) {
414                 module_put(ss->owner);
415                 nfnl_unlock(subsys_id);
416                 netlink_ack(oskb, nlh, -ERESTART, NULL);
417                 return kfree_skb(skb);
418         }
419
420         nfnl_unlock(subsys_id);
421
422         while (skb->len >= nlmsg_total_size(0)) {
423                 int msglen, type;
424
425                 if (fatal_signal_pending(current)) {
426                         nfnl_err_reset(&err_list);
427                         err = -EINTR;
428                         status = NFNL_BATCH_FAILURE;
429                         goto done;
430                 }
431
432                 memset(&extack, 0, sizeof(extack));
433                 nlh = nlmsg_hdr(skb);
434                 err = 0;
435
436                 if (nlh->nlmsg_len < NLMSG_HDRLEN ||
437                     skb->len < nlh->nlmsg_len ||
438                     nlmsg_len(nlh) < sizeof(struct nfgenmsg)) {
439                         nfnl_err_reset(&err_list);
440                         status |= NFNL_BATCH_FAILURE;
441                         goto done;
442                 }
443
444                 /* Only requests are handled by the kernel */
445                 if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
446                         err = -EINVAL;
447                         goto ack;
448                 }
449
450                 type = nlh->nlmsg_type;
451                 if (type == NFNL_MSG_BATCH_BEGIN) {
452                         /* Malformed: Batch begin twice */
453                         nfnl_err_reset(&err_list);
454                         status |= NFNL_BATCH_FAILURE;
455                         goto done;
456                 } else if (type == NFNL_MSG_BATCH_END) {
457                         status |= NFNL_BATCH_DONE;
458                         goto done;
459                 } else if (type < NLMSG_MIN_TYPE) {
460                         err = -EINVAL;
461                         goto ack;
462                 }
463
464                 /* We only accept a batch with messages for the same
465                  * subsystem.
466                  */
467                 if (NFNL_SUBSYS_ID(type) != subsys_id) {
468                         err = -EINVAL;
469                         goto ack;
470                 }
471
472                 nc = nfnetlink_find_client(type, ss);
473                 if (!nc) {
474                         err = -EINVAL;
475                         goto ack;
476                 }
477
478                 if (nc->type != NFNL_CB_BATCH) {
479                         err = -EINVAL;
480                         goto ack;
481                 }
482
483                 {
484                         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
485                         struct nfnl_net *nfnlnet = nfnl_pernet(net);
486                         struct nlattr *cda[NFNL_MAX_ATTR_COUNT + 1];
487                         struct nlattr *attr = (void *)nlh + min_len;
488                         u8 cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
489                         int attrlen = nlh->nlmsg_len - min_len;
490                         struct nfnl_info info = {
491                                 .net    = net,
492                                 .sk     = nfnlnet->nfnl,
493                                 .nlh    = nlh,
494                                 .extack = &extack,
495                         };
496
497                         /* Sanity-check NFTA_MAX_ATTR */
498                         if (ss->cb[cb_id].attr_count > NFNL_MAX_ATTR_COUNT) {
499                                 err = -ENOMEM;
500                                 goto ack;
501                         }
502
503                         err = nla_parse_deprecated(cda,
504                                                    ss->cb[cb_id].attr_count,
505                                                    attr, attrlen,
506                                                    ss->cb[cb_id].policy, NULL);
507                         if (err < 0)
508                                 goto ack;
509
510                         err = nc->call(skb, &info, (const struct nlattr **)cda);
511
512                         /* The lock was released to autoload some module, we
513                          * have to abort and start from scratch using the
514                          * original skb.
515                          */
516                         if (err == -EAGAIN) {
517                                 status |= NFNL_BATCH_REPLAY;
518                                 goto done;
519                         }
520                 }
521 ack:
522                 if (nlh->nlmsg_flags & NLM_F_ACK || err) {
523                         /* Errors are delivered once the full batch has been
524                          * processed, this avoids that the same error is
525                          * reported several times when replaying the batch.
526                          */
527                         if (nfnl_err_add(&err_list, nlh, err, &extack) < 0) {
528                                 /* We failed to enqueue an error, reset the
529                                  * list of errors and send OOM to userspace
530                                  * pointing to the batch header.
531                                  */
532                                 nfnl_err_reset(&err_list);
533                                 netlink_ack(oskb, nlmsg_hdr(oskb), -ENOMEM,
534                                             NULL);
535                                 status |= NFNL_BATCH_FAILURE;
536                                 goto done;
537                         }
538                         /* We don't stop processing the batch on errors, thus,
539                          * userspace gets all the errors that the batch
540                          * triggers.
541                          */
542                         if (err)
543                                 status |= NFNL_BATCH_FAILURE;
544                 }
545
546                 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
547                 if (msglen > skb->len)
548                         msglen = skb->len;
549                 skb_pull(skb, msglen);
550         }
551 done:
552         if (status & NFNL_BATCH_REPLAY) {
553                 ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD);
554                 nfnl_err_reset(&err_list);
555                 kfree_skb(skb);
556                 module_put(ss->owner);
557                 goto replay;
558         } else if (status == NFNL_BATCH_DONE) {
559                 err = ss->commit(net, oskb);
560                 if (err == -EAGAIN) {
561                         status |= NFNL_BATCH_REPLAY;
562                         goto done;
563                 } else if (err) {
564                         ss->abort(net, oskb, NFNL_ABORT_NONE);
565                         netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
566                 }
567         } else {
568                 enum nfnl_abort_action abort_action;
569
570                 if (status & NFNL_BATCH_FAILURE)
571                         abort_action = NFNL_ABORT_NONE;
572                 else
573                         abort_action = NFNL_ABORT_VALIDATE;
574
575                 err = ss->abort(net, oskb, abort_action);
576                 if (err == -EAGAIN) {
577                         nfnl_err_reset(&err_list);
578                         kfree_skb(skb);
579                         module_put(ss->owner);
580                         status |= NFNL_BATCH_FAILURE;
581                         goto replay_abort;
582                 }
583         }
584         if (ss->cleanup)
585                 ss->cleanup(net);
586
587         nfnl_err_deliver(&err_list, oskb);
588         kfree_skb(skb);
589         module_put(ss->owner);
590 }
591
592 static const struct nla_policy nfnl_batch_policy[NFNL_BATCH_MAX + 1] = {
593         [NFNL_BATCH_GENID]      = { .type = NLA_U32 },
594 };
595
596 static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh)
597 {
598         int min_len = nlmsg_total_size(sizeof(struct nfgenmsg));
599         struct nlattr *attr = (void *)nlh + min_len;
600         struct nlattr *cda[NFNL_BATCH_MAX + 1];
601         int attrlen = nlh->nlmsg_len - min_len;
602         struct nfgenmsg *nfgenmsg;
603         int msglen, err;
604         u32 gen_id = 0;
605         u16 res_id;
606
607         msglen = NLMSG_ALIGN(nlh->nlmsg_len);
608         if (msglen > skb->len)
609                 msglen = skb->len;
610
611         if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg))
612                 return;
613
614         err = nla_parse_deprecated(cda, NFNL_BATCH_MAX, attr, attrlen,
615                                    nfnl_batch_policy, NULL);
616         if (err < 0) {
617                 netlink_ack(skb, nlh, err, NULL);
618                 return;
619         }
620         if (cda[NFNL_BATCH_GENID])
621                 gen_id = ntohl(nla_get_be32(cda[NFNL_BATCH_GENID]));
622
623         nfgenmsg = nlmsg_data(nlh);
624         skb_pull(skb, msglen);
625         /* Work around old nft using host byte order */
626         if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES)
627                 res_id = NFNL_SUBSYS_NFTABLES;
628         else
629                 res_id = ntohs(nfgenmsg->res_id);
630
631         nfnetlink_rcv_batch(skb, nlh, res_id, gen_id);
632 }
633
634 static void nfnetlink_rcv(struct sk_buff *skb)
635 {
636         struct nlmsghdr *nlh = nlmsg_hdr(skb);
637
638         if (skb->len < NLMSG_HDRLEN ||
639             nlh->nlmsg_len < NLMSG_HDRLEN ||
640             skb->len < nlh->nlmsg_len)
641                 return;
642
643         if (!netlink_net_capable(skb, CAP_NET_ADMIN)) {
644                 netlink_ack(skb, nlh, -EPERM, NULL);
645                 return;
646         }
647
648         if (nlh->nlmsg_type == NFNL_MSG_BATCH_BEGIN)
649                 nfnetlink_rcv_skb_batch(skb, nlh);
650         else
651                 netlink_rcv_skb(skb, nfnetlink_rcv_msg);
652 }
653
654 #ifdef CONFIG_MODULES
655 static int nfnetlink_bind(struct net *net, int group)
656 {
657         const struct nfnetlink_subsystem *ss;
658         int type;
659
660         if (group <= NFNLGRP_NONE || group > NFNLGRP_MAX)
661                 return 0;
662
663         type = nfnl_group2type[group];
664
665         rcu_read_lock();
666         ss = nfnetlink_get_subsys(type << 8);
667         rcu_read_unlock();
668         if (!ss)
669                 request_module_nowait("nfnetlink-subsys-%d", type);
670         return 0;
671 }
672 #endif
673
674 static int __net_init nfnetlink_net_init(struct net *net)
675 {
676         struct nfnl_net *nfnlnet = nfnl_pernet(net);
677         struct netlink_kernel_cfg cfg = {
678                 .groups = NFNLGRP_MAX,
679                 .input  = nfnetlink_rcv,
680 #ifdef CONFIG_MODULES
681                 .bind   = nfnetlink_bind,
682 #endif
683         };
684
685         nfnlnet->nfnl = netlink_kernel_create(net, NETLINK_NETFILTER, &cfg);
686         if (!nfnlnet->nfnl)
687                 return -ENOMEM;
688         return 0;
689 }
690
691 static void __net_exit nfnetlink_net_exit_batch(struct list_head *net_exit_list)
692 {
693         struct nfnl_net *nfnlnet;
694         struct net *net;
695
696         list_for_each_entry(net, net_exit_list, exit_list) {
697                 nfnlnet = nfnl_pernet(net);
698
699                 netlink_kernel_release(nfnlnet->nfnl);
700         }
701 }
702
703 static struct pernet_operations nfnetlink_net_ops = {
704         .init           = nfnetlink_net_init,
705         .exit_batch     = nfnetlink_net_exit_batch,
706         .id             = &nfnetlink_pernet_id,
707         .size           = sizeof(struct nfnl_net),
708 };
709
710 static int __init nfnetlink_init(void)
711 {
712         int i;
713
714         for (i = NFNLGRP_NONE + 1; i <= NFNLGRP_MAX; i++)
715                 BUG_ON(nfnl_group2type[i] == NFNL_SUBSYS_NONE);
716
717         for (i=0; i<NFNL_SUBSYS_COUNT; i++)
718                 __mutex_init(&table[i].mutex, nfnl_lockdep_names[i], &nfnl_lockdep_keys[i]);
719
720         return register_pernet_subsys(&nfnetlink_net_ops);
721 }
722
723 static void __exit nfnetlink_exit(void)
724 {
725         unregister_pernet_subsys(&nfnetlink_net_ops);
726 }
727 module_init(nfnetlink_init);
728 module_exit(nfnetlink_exit);