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netlink: use kfree_rcu() in netlink_release()
[linux-2.6/btrfs-unstable.git] / net / netlink / af_netlink.c
blob4da797fa5ec57641a0fa70b5dd1e6e517884fad4
1 /*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
13 * added netlink_proto_exit
14 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
15 * use nlk_sk, as sk->protinfo is on a diet 8)
16 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
17 * - inc module use count of module that owns
18 * the kernel socket in case userspace opens
19 * socket of same protocol
20 * - remove all module support, since netlink is
21 * mandatory if CONFIG_NET=y these days
22 */
23
24 #include <linux/module.h>
25
26 #include <linux/capability.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/signal.h>
30 #include <linux/sched.h>
31 #include <linux/errno.h>
32 #include <linux/string.h>
33 #include <linux/stat.h>
34 #include <linux/socket.h>
35 #include <linux/un.h>
36 #include <linux/fcntl.h>
37 #include <linux/termios.h>
38 #include <linux/sockios.h>
39 #include <linux/net.h>
40 #include <linux/fs.h>
41 #include <linux/slab.h>
42 #include <asm/uaccess.h>
43 #include <linux/skbuff.h>
44 #include <linux/netdevice.h>
45 #include <linux/rtnetlink.h>
46 #include <linux/proc_fs.h>
47 #include <linux/seq_file.h>
48 #include <linux/notifier.h>
49 #include <linux/security.h>
50 #include <linux/jhash.h>
51 #include <linux/jiffies.h>
52 #include <linux/random.h>
53 #include <linux/bitops.h>
54 #include <linux/mm.h>
55 #include <linux/types.h>
56 #include <linux/audit.h>
57 #include <linux/mutex.h>
58
59 #include <net/net_namespace.h>
60 #include <net/sock.h>
61 #include <net/scm.h>
62 #include <net/netlink.h>
63
64 #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
65 #define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long))
66
67 struct netlink_sock {
68 /* struct sock has to be the first member of netlink_sock */
69 struct sock sk;
70 u32 portid;
71 u32 dst_portid;
72 u32 dst_group;
73 u32 flags;
74 u32 subscriptions;
75 u32 ngroups;
76 unsigned long *groups;
77 unsigned long state;
78 wait_queue_head_t wait;
79 struct netlink_callback *cb;
80 struct mutex *cb_mutex;
81 struct mutex cb_def_mutex;
82 void (*netlink_rcv)(struct sk_buff *skb);
83 void (*netlink_bind)(int group);
84 struct module *module;
85 };
86
87 struct listeners {
88 struct rcu_head rcu;
89 unsigned long masks[0];
90 };
91
92 #define NETLINK_KERNEL_SOCKET 0x1
93 #define NETLINK_RECV_PKTINFO 0x2
94 #define NETLINK_BROADCAST_SEND_ERROR 0x4
95 #define NETLINK_RECV_NO_ENOBUFS 0x8
96
97 static inline struct netlink_sock *nlk_sk(struct sock *sk)
98 {
99 return container_of(sk, struct netlink_sock, sk);
100 }
101
102 static inline int netlink_is_kernel(struct sock *sk)
103 {
104 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
105 }
106
107 struct nl_portid_hash {
108 struct hlist_head *table;
109 unsigned long rehash_time;
110
111 unsigned int mask;
112 unsigned int shift;
113
114 unsigned int entries;
115 unsigned int max_shift;
116
117 u32 rnd;
118 };
119
120 struct netlink_table {
121 struct nl_portid_hash hash;
122 struct hlist_head mc_list;
123 struct listeners __rcu *listeners;
124 unsigned int flags;
125 unsigned int groups;
126 struct mutex *cb_mutex;
127 struct module *module;
128 void (*bind)(int group);
129 int registered;
130 };
131
132 static struct netlink_table *nl_table;
133
134 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
135
136 static int netlink_dump(struct sock *sk);
137
138 static DEFINE_RWLOCK(nl_table_lock);
139 static atomic_t nl_table_users = ATOMIC_INIT(0);
140
141 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
142
143 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
144
145 static inline u32 netlink_group_mask(u32 group)
146 {
147 return group ? 1 << (group - 1) : 0;
148 }
149
150 static inline struct hlist_head *nl_portid_hashfn(struct nl_portid_hash *hash, u32 portid)
151 {
152 return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask];
153 }
154
155 static void netlink_destroy_callback(struct netlink_callback *cb)
156 {
157 kfree_skb(cb->skb);
158 kfree(cb);
159 }
160
161 static void netlink_consume_callback(struct netlink_callback *cb)
162 {
163 consume_skb(cb->skb);
164 kfree(cb);
165 }
166
167 static void netlink_sock_destruct(struct sock *sk)
168 {
169 struct netlink_sock *nlk = nlk_sk(sk);
170
171 if (nlk->cb) {
172 if (nlk->cb->done)
173 nlk->cb->done(nlk->cb);
174
175 module_put(nlk->cb->module);
176 netlink_destroy_callback(nlk->cb);
177 }
178
179 skb_queue_purge(&sk->sk_receive_queue);
180
181 if (!sock_flag(sk, SOCK_DEAD)) {
182 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
183 return;
184 }
185
186 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
187 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
188 WARN_ON(nlk_sk(sk)->groups);
189 }
190
191 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
192 * SMP. Look, when several writers sleep and reader wakes them up, all but one
193 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
194 * this, _but_ remember, it adds useless work on UP machines.
195 */
196
197 void netlink_table_grab(void)
198 __acquires(nl_table_lock)
199 {
200 might_sleep();
201
202 write_lock_irq(&nl_table_lock);
203
204 if (atomic_read(&nl_table_users)) {
205 DECLARE_WAITQUEUE(wait, current);
206
207 add_wait_queue_exclusive(&nl_table_wait, &wait);
208 for (;;) {
209 set_current_state(TASK_UNINTERRUPTIBLE);
210 if (atomic_read(&nl_table_users) == 0)
211 break;
212 write_unlock_irq(&nl_table_lock);
213 schedule();
214 write_lock_irq(&nl_table_lock);
215 }
216
217 __set_current_state(TASK_RUNNING);
218 remove_wait_queue(&nl_table_wait, &wait);
219 }
220 }
221
222 void netlink_table_ungrab(void)
223 __releases(nl_table_lock)
224 {
225 write_unlock_irq(&nl_table_lock);
226 wake_up(&nl_table_wait);
227 }
228
229 static inline void
230 netlink_lock_table(void)
231 {
232 /* read_lock() synchronizes us to netlink_table_grab */
233
234 read_lock(&nl_table_lock);
235 atomic_inc(&nl_table_users);
236 read_unlock(&nl_table_lock);
237 }
238
239 static inline void
240 netlink_unlock_table(void)
241 {
242 if (atomic_dec_and_test(&nl_table_users))
243 wake_up(&nl_table_wait);
244 }
245
246 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
247 {
248 struct nl_portid_hash *hash = &nl_table[protocol].hash;
249 struct hlist_head *head;
250 struct sock *sk;
251 struct hlist_node *node;
252
253 read_lock(&nl_table_lock);
254 head = nl_portid_hashfn(hash, portid);
255 sk_for_each(sk, node, head) {
256 if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->portid == portid)) {
257 sock_hold(sk);
258 goto found;
259 }
260 }
261 sk = NULL;
262 found:
263 read_unlock(&nl_table_lock);
264 return sk;
265 }
266
267 static struct hlist_head *nl_portid_hash_zalloc(size_t size)
268 {
269 if (size <= PAGE_SIZE)
270 return kzalloc(size, GFP_ATOMIC);
271 else
272 return (struct hlist_head *)
273 __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
274 get_order(size));
275 }
276
277 static void nl_portid_hash_free(struct hlist_head *table, size_t size)
278 {
279 if (size <= PAGE_SIZE)
280 kfree(table);
281 else
282 free_pages((unsigned long)table, get_order(size));
283 }
284
285 static int nl_portid_hash_rehash(struct nl_portid_hash *hash, int grow)
286 {
287 unsigned int omask, mask, shift;
288 size_t osize, size;
289 struct hlist_head *otable, *table;
290 int i;
291
292 omask = mask = hash->mask;
293 osize = size = (mask + 1) * sizeof(*table);
294 shift = hash->shift;
295
296 if (grow) {
297 if (++shift > hash->max_shift)
298 return 0;
299 mask = mask * 2 + 1;
300 size *= 2;
301 }
302
303 table = nl_portid_hash_zalloc(size);
304 if (!table)
305 return 0;
306
307 otable = hash->table;
308 hash->table = table;
309 hash->mask = mask;
310 hash->shift = shift;
311 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
312
313 for (i = 0; i <= omask; i++) {
314 struct sock *sk;
315 struct hlist_node *node, *tmp;
316
317 sk_for_each_safe(sk, node, tmp, &otable[i])
318 __sk_add_node(sk, nl_portid_hashfn(hash, nlk_sk(sk)->portid));
319 }
320
321 nl_portid_hash_free(otable, osize);
322 hash->rehash_time = jiffies + 10 * 60 * HZ;
323 return 1;
324 }
325
326 static inline int nl_portid_hash_dilute(struct nl_portid_hash *hash, int len)
327 {
328 int avg = hash->entries >> hash->shift;
329
330 if (unlikely(avg > 1) && nl_portid_hash_rehash(hash, 1))
331 return 1;
332
333 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
334 nl_portid_hash_rehash(hash, 0);
335 return 1;
336 }
337
338 return 0;
339 }
340
341 static const struct proto_ops netlink_ops;
342
343 static void
344 netlink_update_listeners(struct sock *sk)
345 {
346 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
347 struct hlist_node *node;
348 unsigned long mask;
349 unsigned int i;
350 struct listeners *listeners;
351
352 listeners = nl_deref_protected(tbl->listeners);
353 if (!listeners)
354 return;
355
356 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
357 mask = 0;
358 sk_for_each_bound(sk, node, &tbl->mc_list) {
359 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
360 mask |= nlk_sk(sk)->groups[i];
361 }
362 listeners->masks[i] = mask;
363 }
364 /* this function is only called with the netlink table "grabbed", which
365 * makes sure updates are visible before bind or setsockopt return. */
366 }
367
368 static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
369 {
370 struct nl_portid_hash *hash = &nl_table[sk->sk_protocol].hash;
371 struct hlist_head *head;
372 int err = -EADDRINUSE;
373 struct sock *osk;
374 struct hlist_node *node;
375 int len;
376
377 netlink_table_grab();
378 head = nl_portid_hashfn(hash, portid);
379 len = 0;
380 sk_for_each(osk, node, head) {
381 if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->portid == portid))
382 break;
383 len++;
384 }
385 if (node)
386 goto err;
387
388 err = -EBUSY;
389 if (nlk_sk(sk)->portid)
390 goto err;
391
392 err = -ENOMEM;
393 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
394 goto err;
395
396 if (len && nl_portid_hash_dilute(hash, len))
397 head = nl_portid_hashfn(hash, portid);
398 hash->entries++;
399 nlk_sk(sk)->portid = portid;
400 sk_add_node(sk, head);
401 err = 0;
402
403 err:
404 netlink_table_ungrab();
405 return err;
406 }
407
408 static void netlink_remove(struct sock *sk)
409 {
410 netlink_table_grab();
411 if (sk_del_node_init(sk))
412 nl_table[sk->sk_protocol].hash.entries--;
413 if (nlk_sk(sk)->subscriptions)
414 __sk_del_bind_node(sk);
415 netlink_table_ungrab();
416 }
417
418 static struct proto netlink_proto = {
419 .name = "NETLINK",
420 .owner = THIS_MODULE,
421 .obj_size = sizeof(struct netlink_sock),
422 };
423
424 static int __netlink_create(struct net *net, struct socket *sock,
425 struct mutex *cb_mutex, int protocol)
426 {
427 struct sock *sk;
428 struct netlink_sock *nlk;
429
430 sock->ops = &netlink_ops;
431
432 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
433 if (!sk)
434 return -ENOMEM;
435
436 sock_init_data(sock, sk);
437
438 nlk = nlk_sk(sk);
439 if (cb_mutex) {
440 nlk->cb_mutex = cb_mutex;
441 } else {
442 nlk->cb_mutex = &nlk->cb_def_mutex;
443 mutex_init(nlk->cb_mutex);
444 }
445 init_waitqueue_head(&nlk->wait);
446
447 sk->sk_destruct = netlink_sock_destruct;
448 sk->sk_protocol = protocol;
449 return 0;
450 }
451
452 static int netlink_create(struct net *net, struct socket *sock, int protocol,
453 int kern)
454 {
455 struct module *module = NULL;
456 struct mutex *cb_mutex;
457 struct netlink_sock *nlk;
458 void (*bind)(int group);
459 int err = 0;
460
461 sock->state = SS_UNCONNECTED;
462
463 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
464 return -ESOCKTNOSUPPORT;
465
466 if (protocol < 0 || protocol >= MAX_LINKS)
467 return -EPROTONOSUPPORT;
468
469 netlink_lock_table();
470 #ifdef CONFIG_MODULES
471 if (!nl_table[protocol].registered) {
472 netlink_unlock_table();
473 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
474 netlink_lock_table();
475 }
476 #endif
477 if (nl_table[protocol].registered &&
478 try_module_get(nl_table[protocol].module))
479 module = nl_table[protocol].module;
480 else
481 err = -EPROTONOSUPPORT;
482 cb_mutex = nl_table[protocol].cb_mutex;
483 bind = nl_table[protocol].bind;
484 netlink_unlock_table();
485
486 if (err < 0)
487 goto out;
488
489 err = __netlink_create(net, sock, cb_mutex, protocol);
490 if (err < 0)
491 goto out_module;
492
493 local_bh_disable();
494 sock_prot_inuse_add(net, &netlink_proto, 1);
495 local_bh_enable();
496
497 nlk = nlk_sk(sock->sk);
498 nlk->module = module;
499 nlk->netlink_bind = bind;
500 out:
501 return err;
502
503 out_module:
504 module_put(module);
505 goto out;
506 }
507
508 static int netlink_release(struct socket *sock)
509 {
510 struct sock *sk = sock->sk;
511 struct netlink_sock *nlk;
512
513 if (!sk)
514 return 0;
515
516 netlink_remove(sk);
517 sock_orphan(sk);
518 nlk = nlk_sk(sk);
519
520 /*
521 * OK. Socket is unlinked, any packets that arrive now
522 * will be purged.
523 */
524
525 sock->sk = NULL;
526 wake_up_interruptible_all(&nlk->wait);
527
528 skb_queue_purge(&sk->sk_write_queue);
529
530 if (nlk->portid) {
531 struct netlink_notify n = {
532 .net = sock_net(sk),
533 .protocol = sk->sk_protocol,
534 .portid = nlk->portid,
535 };
536 atomic_notifier_call_chain(&netlink_chain,
537 NETLINK_URELEASE, &n);
538 }
539
540 module_put(nlk->module);
541
542 netlink_table_grab();
543 if (netlink_is_kernel(sk)) {
544 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
545 if (--nl_table[sk->sk_protocol].registered == 0) {
546 struct listeners *old;
547
548 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
549 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
550 kfree_rcu(old, rcu);
551 nl_table[sk->sk_protocol].module = NULL;
552 nl_table[sk->sk_protocol].bind = NULL;
553 nl_table[sk->sk_protocol].flags = 0;
554 nl_table[sk->sk_protocol].registered = 0;
555 }
556 } else if (nlk->subscriptions) {
557 netlink_update_listeners(sk);
558 }
559 netlink_table_ungrab();
560
561 kfree(nlk->groups);
562 nlk->groups = NULL;
563
564 local_bh_disable();
565 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
566 local_bh_enable();
567 sock_put(sk);
568 return 0;
569 }
570
571 static int netlink_autobind(struct socket *sock)
572 {
573 struct sock *sk = sock->sk;
574 struct net *net = sock_net(sk);
575 struct nl_portid_hash *hash = &nl_table[sk->sk_protocol].hash;
576 struct hlist_head *head;
577 struct sock *osk;
578 struct hlist_node *node;
579 s32 portid = task_tgid_vnr(current);
580 int err;
581 static s32 rover = -4097;
582
583 retry:
584 cond_resched();
585 netlink_table_grab();
586 head = nl_portid_hashfn(hash, portid);
587 sk_for_each(osk, node, head) {
588 if (!net_eq(sock_net(osk), net))
589 continue;
590 if (nlk_sk(osk)->portid == portid) {
591 /* Bind collision, search negative portid values. */
592 portid = rover--;
593 if (rover > -4097)
594 rover = -4097;
595 netlink_table_ungrab();
596 goto retry;
597 }
598 }
599 netlink_table_ungrab();
600
601 err = netlink_insert(sk, net, portid);
602 if (err == -EADDRINUSE)
603 goto retry;
604
605 /* If 2 threads race to autobind, that is fine. */
606 if (err == -EBUSY)
607 err = 0;
608
609 return err;
610 }
611
612 static inline int netlink_capable(const struct socket *sock, unsigned int flag)
613 {
614 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
615 capable(CAP_NET_ADMIN);
616 }
617
618 static void
619 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
620 {
621 struct netlink_sock *nlk = nlk_sk(sk);
622
623 if (nlk->subscriptions && !subscriptions)
624 __sk_del_bind_node(sk);
625 else if (!nlk->subscriptions && subscriptions)
626 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
627 nlk->subscriptions = subscriptions;
628 }
629
630 static int netlink_realloc_groups(struct sock *sk)
631 {
632 struct netlink_sock *nlk = nlk_sk(sk);
633 unsigned int groups;
634 unsigned long *new_groups;
635 int err = 0;
636
637 netlink_table_grab();
638
639 groups = nl_table[sk->sk_protocol].groups;
640 if (!nl_table[sk->sk_protocol].registered) {
641 err = -ENOENT;
642 goto out_unlock;
643 }
644
645 if (nlk->ngroups >= groups)
646 goto out_unlock;
647
648 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
649 if (new_groups == NULL) {
650 err = -ENOMEM;
651 goto out_unlock;
652 }
653 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
654 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
655
656 nlk->groups = new_groups;
657 nlk->ngroups = groups;
658 out_unlock:
659 netlink_table_ungrab();
660 return err;
661 }
662
663 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
664 int addr_len)
665 {
666 struct sock *sk = sock->sk;
667 struct net *net = sock_net(sk);
668 struct netlink_sock *nlk = nlk_sk(sk);
669 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
670 int err;
671
672 if (nladdr->nl_family != AF_NETLINK)
673 return -EINVAL;
674
675 /* Only superuser is allowed to listen multicasts */
676 if (nladdr->nl_groups) {
677 if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV))
678 return -EPERM;
679 err = netlink_realloc_groups(sk);
680 if (err)
681 return err;
682 }
683
684 if (nlk->portid) {
685 if (nladdr->nl_pid != nlk->portid)
686 return -EINVAL;
687 } else {
688 err = nladdr->nl_pid ?
689 netlink_insert(sk, net, nladdr->nl_pid) :
690 netlink_autobind(sock);
691 if (err)
692 return err;
693 }
694
695 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
696 return 0;
697
698 netlink_table_grab();
699 netlink_update_subscriptions(sk, nlk->subscriptions +
700 hweight32(nladdr->nl_groups) -
701 hweight32(nlk->groups[0]));
702 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
703 netlink_update_listeners(sk);
704 netlink_table_ungrab();
705
706 if (nlk->netlink_bind && nlk->groups[0]) {
707 int i;
708
709 for (i=0; i<nlk->ngroups; i++) {
710 if (test_bit(i, nlk->groups))
711 nlk->netlink_bind(i);
712 }
713 }
714
715 return 0;
716 }
717
718 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
719 int alen, int flags)
720 {
721 int err = 0;
722 struct sock *sk = sock->sk;
723 struct netlink_sock *nlk = nlk_sk(sk);
724 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
725
726 if (alen < sizeof(addr->sa_family))
727 return -EINVAL;
728
729 if (addr->sa_family == AF_UNSPEC) {
730 sk->sk_state = NETLINK_UNCONNECTED;
731 nlk->dst_portid = 0;
732 nlk->dst_group = 0;
733 return 0;
734 }
735 if (addr->sa_family != AF_NETLINK)
736 return -EINVAL;
737
738 /* Only superuser is allowed to send multicasts */
739 if (nladdr->nl_groups && !netlink_capable(sock, NL_CFG_F_NONROOT_SEND))
740 return -EPERM;
741
742 if (!nlk->portid)
743 err = netlink_autobind(sock);
744
745 if (err == 0) {
746 sk->sk_state = NETLINK_CONNECTED;
747 nlk->dst_portid = nladdr->nl_pid;
748 nlk->dst_group = ffs(nladdr->nl_groups);
749 }
750
751 return err;
752 }
753
754 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
755 int *addr_len, int peer)
756 {
757 struct sock *sk = sock->sk;
758 struct netlink_sock *nlk = nlk_sk(sk);
759 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
760
761 nladdr->nl_family = AF_NETLINK;
762 nladdr->nl_pad = 0;
763 *addr_len = sizeof(*nladdr);
764
765 if (peer) {
766 nladdr->nl_pid = nlk->dst_portid;
767 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
768 } else {
769 nladdr->nl_pid = nlk->portid;
770 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
771 }
772 return 0;
773 }
774
775 static void netlink_overrun(struct sock *sk)
776 {
777 struct netlink_sock *nlk = nlk_sk(sk);
778
779 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
780 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
781 sk->sk_err = ENOBUFS;
782 sk->sk_error_report(sk);
783 }
784 }
785 atomic_inc(&sk->sk_drops);
786 }
787
788 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
789 {
790 struct sock *sock;
791 struct netlink_sock *nlk;
792
793 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
794 if (!sock)
795 return ERR_PTR(-ECONNREFUSED);
796
797 /* Don't bother queuing skb if kernel socket has no input function */
798 nlk = nlk_sk(sock);
799 if (sock->sk_state == NETLINK_CONNECTED &&
800 nlk->dst_portid != nlk_sk(ssk)->portid) {
801 sock_put(sock);
802 return ERR_PTR(-ECONNREFUSED);
803 }
804 return sock;
805 }
806
807 struct sock *netlink_getsockbyfilp(struct file *filp)
808 {
809 struct inode *inode = filp->f_path.dentry->d_inode;
810 struct sock *sock;
811
812 if (!S_ISSOCK(inode->i_mode))
813 return ERR_PTR(-ENOTSOCK);
814
815 sock = SOCKET_I(inode)->sk;
816 if (sock->sk_family != AF_NETLINK)
817 return ERR_PTR(-EINVAL);
818
819 sock_hold(sock);
820 return sock;
821 }
822
823 /*
824 * Attach a skb to a netlink socket.
825 * The caller must hold a reference to the destination socket. On error, the
826 * reference is dropped. The skb is not send to the destination, just all
827 * all error checks are performed and memory in the queue is reserved.
828 * Return values:
829 * < 0: error. skb freed, reference to sock dropped.
830 * 0: continue
831 * 1: repeat lookup - reference dropped while waiting for socket memory.
832 */
833 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
834 long *timeo, struct sock *ssk)
835 {
836 struct netlink_sock *nlk;
837
838 nlk = nlk_sk(sk);
839
840 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
841 test_bit(0, &nlk->state)) {
842 DECLARE_WAITQUEUE(wait, current);
843 if (!*timeo) {
844 if (!ssk || netlink_is_kernel(ssk))
845 netlink_overrun(sk);
846 sock_put(sk);
847 kfree_skb(skb);
848 return -EAGAIN;
849 }
850
851 __set_current_state(TASK_INTERRUPTIBLE);
852 add_wait_queue(&nlk->wait, &wait);
853
854 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
855 test_bit(0, &nlk->state)) &&
856 !sock_flag(sk, SOCK_DEAD))
857 *timeo = schedule_timeout(*timeo);
858
859 __set_current_state(TASK_RUNNING);
860 remove_wait_queue(&nlk->wait, &wait);
861 sock_put(sk);
862
863 if (signal_pending(current)) {
864 kfree_skb(skb);
865 return sock_intr_errno(*timeo);
866 }
867 return 1;
868 }
869 skb_set_owner_r(skb, sk);
870 return 0;
871 }
872
873 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
874 {
875 int len = skb->len;
876
877 skb_queue_tail(&sk->sk_receive_queue, skb);
878 sk->sk_data_ready(sk, len);
879 return len;
880 }
881
882 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
883 {
884 int len = __netlink_sendskb(sk, skb);
885
886 sock_put(sk);
887 return len;
888 }
889
890 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
891 {
892 kfree_skb(skb);
893 sock_put(sk);
894 }
895
896 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
897 {
898 int delta;
899
900 skb_orphan(skb);
901
902 delta = skb->end - skb->tail;
903 if (delta * 2 < skb->truesize)
904 return skb;
905
906 if (skb_shared(skb)) {
907 struct sk_buff *nskb = skb_clone(skb, allocation);
908 if (!nskb)
909 return skb;
910 consume_skb(skb);
911 skb = nskb;
912 }
913
914 if (!pskb_expand_head(skb, 0, -delta, allocation))
915 skb->truesize -= delta;
916
917 return skb;
918 }
919
920 static void netlink_rcv_wake(struct sock *sk)
921 {
922 struct netlink_sock *nlk = nlk_sk(sk);
923
924 if (skb_queue_empty(&sk->sk_receive_queue))
925 clear_bit(0, &nlk->state);
926 if (!test_bit(0, &nlk->state))
927 wake_up_interruptible(&nlk->wait);
928 }
929
930 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
931 struct sock *ssk)
932 {
933 int ret;
934 struct netlink_sock *nlk = nlk_sk(sk);
935
936 ret = -ECONNREFUSED;
937 if (nlk->netlink_rcv != NULL) {
938 ret = skb->len;
939 skb_set_owner_r(skb, sk);
940 NETLINK_CB(skb).ssk = ssk;
941 nlk->netlink_rcv(skb);
942 consume_skb(skb);
943 } else {
944 kfree_skb(skb);
945 }
946 sock_put(sk);
947 return ret;
948 }
949
950 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
951 u32 portid, int nonblock)
952 {
953 struct sock *sk;
954 int err;
955 long timeo;
956
957 skb = netlink_trim(skb, gfp_any());
958
959 timeo = sock_sndtimeo(ssk, nonblock);
960 retry:
961 sk = netlink_getsockbyportid(ssk, portid);
962 if (IS_ERR(sk)) {
963 kfree_skb(skb);
964 return PTR_ERR(sk);
965 }
966 if (netlink_is_kernel(sk))
967 return netlink_unicast_kernel(sk, skb, ssk);
968
969 if (sk_filter(sk, skb)) {
970 err = skb->len;
971 kfree_skb(skb);
972 sock_put(sk);
973 return err;
974 }
975
976 err = netlink_attachskb(sk, skb, &timeo, ssk);
977 if (err == 1)
978 goto retry;
979 if (err)
980 return err;
981
982 return netlink_sendskb(sk, skb);
983 }
984 EXPORT_SYMBOL(netlink_unicast);
985
986 int netlink_has_listeners(struct sock *sk, unsigned int group)
987 {
988 int res = 0;
989 struct listeners *listeners;
990
991 BUG_ON(!netlink_is_kernel(sk));
992
993 rcu_read_lock();
994 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
995
996 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
997 res = test_bit(group - 1, listeners->masks);
998
999 rcu_read_unlock();
1000
1001 return res;
1002 }
1003 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1004
1005 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1006 {
1007 struct netlink_sock *nlk = nlk_sk(sk);
1008
1009 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1010 !test_bit(0, &nlk->state)) {
1011 skb_set_owner_r(skb, sk);
1012 __netlink_sendskb(sk, skb);
1013 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1014 }
1015 return -1;
1016 }
1017
1018 struct netlink_broadcast_data {
1019 struct sock *exclude_sk;
1020 struct net *net;
1021 u32 portid;
1022 u32 group;
1023 int failure;
1024 int delivery_failure;
1025 int congested;
1026 int delivered;
1027 gfp_t allocation;
1028 struct sk_buff *skb, *skb2;
1029 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1030 void *tx_data;
1031 };
1032
1033 static int do_one_broadcast(struct sock *sk,
1034 struct netlink_broadcast_data *p)
1035 {
1036 struct netlink_sock *nlk = nlk_sk(sk);
1037 int val;
1038
1039 if (p->exclude_sk == sk)
1040 goto out;
1041
1042 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1043 !test_bit(p->group - 1, nlk->groups))
1044 goto out;
1045
1046 if (!net_eq(sock_net(sk), p->net))
1047 goto out;
1048
1049 if (p->failure) {
1050 netlink_overrun(sk);
1051 goto out;
1052 }
1053
1054 sock_hold(sk);
1055 if (p->skb2 == NULL) {
1056 if (skb_shared(p->skb)) {
1057 p->skb2 = skb_clone(p->skb, p->allocation);
1058 } else {
1059 p->skb2 = skb_get(p->skb);
1060 /*
1061 * skb ownership may have been set when
1062 * delivered to a previous socket.
1063 */
1064 skb_orphan(p->skb2);
1065 }
1066 }
1067 if (p->skb2 == NULL) {
1068 netlink_overrun(sk);
1069 /* Clone failed. Notify ALL listeners. */
1070 p->failure = 1;
1071 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1072 p->delivery_failure = 1;
1073 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1074 kfree_skb(p->skb2);
1075 p->skb2 = NULL;
1076 } else if (sk_filter(sk, p->skb2)) {
1077 kfree_skb(p->skb2);
1078 p->skb2 = NULL;
1079 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1080 netlink_overrun(sk);
1081 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1082 p->delivery_failure = 1;
1083 } else {
1084 p->congested |= val;
1085 p->delivered = 1;
1086 p->skb2 = NULL;
1087 }
1088 sock_put(sk);
1089
1090 out:
1091 return 0;
1092 }
1093
1094 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1095 u32 group, gfp_t allocation,
1096 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1097 void *filter_data)
1098 {
1099 struct net *net = sock_net(ssk);
1100 struct netlink_broadcast_data info;
1101 struct hlist_node *node;
1102 struct sock *sk;
1103
1104 skb = netlink_trim(skb, allocation);
1105
1106 info.exclude_sk = ssk;
1107 info.net = net;
1108 info.portid = portid;
1109 info.group = group;
1110 info.failure = 0;
1111 info.delivery_failure = 0;
1112 info.congested = 0;
1113 info.delivered = 0;
1114 info.allocation = allocation;
1115 info.skb = skb;
1116 info.skb2 = NULL;
1117 info.tx_filter = filter;
1118 info.tx_data = filter_data;
1119
1120 /* While we sleep in clone, do not allow to change socket list */
1121
1122 netlink_lock_table();
1123
1124 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1125 do_one_broadcast(sk, &info);
1126
1127 consume_skb(skb);
1128
1129 netlink_unlock_table();
1130
1131 if (info.delivery_failure) {
1132 kfree_skb(info.skb2);
1133 return -ENOBUFS;
1134 }
1135 consume_skb(info.skb2);
1136
1137 if (info.delivered) {
1138 if (info.congested && (allocation & __GFP_WAIT))
1139 yield();
1140 return 0;
1141 }
1142 return -ESRCH;
1143 }
1144 EXPORT_SYMBOL(netlink_broadcast_filtered);
1145
1146 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1147 u32 group, gfp_t allocation)
1148 {
1149 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1150 NULL, NULL);
1151 }
1152 EXPORT_SYMBOL(netlink_broadcast);
1153
1154 struct netlink_set_err_data {
1155 struct sock *exclude_sk;
1156 u32 portid;
1157 u32 group;
1158 int code;
1159 };
1160
1161 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1162 {
1163 struct netlink_sock *nlk = nlk_sk(sk);
1164 int ret = 0;
1165
1166 if (sk == p->exclude_sk)
1167 goto out;
1168
1169 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1170 goto out;
1171
1172 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1173 !test_bit(p->group - 1, nlk->groups))
1174 goto out;
1175
1176 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
1177 ret = 1;
1178 goto out;
1179 }
1180
1181 sk->sk_err = p->code;
1182 sk->sk_error_report(sk);
1183 out:
1184 return ret;
1185 }
1186
1187 /**
1188 * netlink_set_err - report error to broadcast listeners
1189 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1190 * @portid: the PORTID of a process that we want to skip (if any)
1191 * @groups: the broadcast group that will notice the error
1192 * @code: error code, must be negative (as usual in kernelspace)
1193 *
1194 * This function returns the number of broadcast listeners that have set the
1195 * NETLINK_RECV_NO_ENOBUFS socket option.
1196 */
1197 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1198 {
1199 struct netlink_set_err_data info;
1200 struct hlist_node *node;
1201 struct sock *sk;
1202 int ret = 0;
1203
1204 info.exclude_sk = ssk;
1205 info.portid = portid;
1206 info.group = group;
1207 /* sk->sk_err wants a positive error value */
1208 info.code = -code;
1209
1210 read_lock(&nl_table_lock);
1211
1212 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1213 ret += do_one_set_err(sk, &info);
1214
1215 read_unlock(&nl_table_lock);
1216 return ret;
1217 }
1218 EXPORT_SYMBOL(netlink_set_err);
1219
1220 /* must be called with netlink table grabbed */
1221 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1222 unsigned int group,
1223 int is_new)
1224 {
1225 int old, new = !!is_new, subscriptions;
1226
1227 old = test_bit(group - 1, nlk->groups);
1228 subscriptions = nlk->subscriptions - old + new;
1229 if (new)
1230 __set_bit(group - 1, nlk->groups);
1231 else
1232 __clear_bit(group - 1, nlk->groups);
1233 netlink_update_subscriptions(&nlk->sk, subscriptions);
1234 netlink_update_listeners(&nlk->sk);
1235 }
1236
1237 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1238 char __user *optval, unsigned int optlen)
1239 {
1240 struct sock *sk = sock->sk;
1241 struct netlink_sock *nlk = nlk_sk(sk);
1242 unsigned int val = 0;
1243 int err;
1244
1245 if (level != SOL_NETLINK)
1246 return -ENOPROTOOPT;
1247
1248 if (optlen >= sizeof(int) &&
1249 get_user(val, (unsigned int __user *)optval))
1250 return -EFAULT;
1251
1252 switch (optname) {
1253 case NETLINK_PKTINFO:
1254 if (val)
1255 nlk->flags |= NETLINK_RECV_PKTINFO;
1256 else
1257 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1258 err = 0;
1259 break;
1260 case NETLINK_ADD_MEMBERSHIP:
1261 case NETLINK_DROP_MEMBERSHIP: {
1262 if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV))
1263 return -EPERM;
1264 err = netlink_realloc_groups(sk);
1265 if (err)
1266 return err;
1267 if (!val || val - 1 >= nlk->ngroups)
1268 return -EINVAL;
1269 netlink_table_grab();
1270 netlink_update_socket_mc(nlk, val,
1271 optname == NETLINK_ADD_MEMBERSHIP);
1272 netlink_table_ungrab();
1273
1274 if (nlk->netlink_bind)
1275 nlk->netlink_bind(val);
1276
1277 err = 0;
1278 break;
1279 }
1280 case NETLINK_BROADCAST_ERROR:
1281 if (val)
1282 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1283 else
1284 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1285 err = 0;
1286 break;
1287 case NETLINK_NO_ENOBUFS:
1288 if (val) {
1289 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1290 clear_bit(0, &nlk->state);
1291 wake_up_interruptible(&nlk->wait);
1292 } else {
1293 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1294 }
1295 err = 0;
1296 break;
1297 default:
1298 err = -ENOPROTOOPT;
1299 }
1300 return err;
1301 }
1302
1303 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1304 char __user *optval, int __user *optlen)
1305 {
1306 struct sock *sk = sock->sk;
1307 struct netlink_sock *nlk = nlk_sk(sk);
1308 int len, val, err;
1309
1310 if (level != SOL_NETLINK)
1311 return -ENOPROTOOPT;
1312
1313 if (get_user(len, optlen))
1314 return -EFAULT;
1315 if (len < 0)
1316 return -EINVAL;
1317
1318 switch (optname) {
1319 case NETLINK_PKTINFO:
1320 if (len < sizeof(int))
1321 return -EINVAL;
1322 len = sizeof(int);
1323 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1324 if (put_user(len, optlen) ||
1325 put_user(val, optval))
1326 return -EFAULT;
1327 err = 0;
1328 break;
1329 case NETLINK_BROADCAST_ERROR:
1330 if (len < sizeof(int))
1331 return -EINVAL;
1332 len = sizeof(int);
1333 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1334 if (put_user(len, optlen) ||
1335 put_user(val, optval))
1336 return -EFAULT;
1337 err = 0;
1338 break;
1339 case NETLINK_NO_ENOBUFS:
1340 if (len < sizeof(int))
1341 return -EINVAL;
1342 len = sizeof(int);
1343 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1344 if (put_user(len, optlen) ||
1345 put_user(val, optval))
1346 return -EFAULT;
1347 err = 0;
1348 break;
1349 default:
1350 err = -ENOPROTOOPT;
1351 }
1352 return err;
1353 }
1354
1355 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1356 {
1357 struct nl_pktinfo info;
1358
1359 info.group = NETLINK_CB(skb).dst_group;
1360 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1361 }
1362
1363 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1364 struct msghdr *msg, size_t len)
1365 {
1366 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1367 struct sock *sk = sock->sk;
1368 struct netlink_sock *nlk = nlk_sk(sk);
1369 struct sockaddr_nl *addr = msg->msg_name;
1370 u32 dst_portid;
1371 u32 dst_group;
1372 struct sk_buff *skb;
1373 int err;
1374 struct scm_cookie scm;
1375
1376 if (msg->msg_flags&MSG_OOB)
1377 return -EOPNOTSUPP;
1378
1379 if (NULL == siocb->scm)
1380 siocb->scm = &scm;
1381
1382 err = scm_send(sock, msg, siocb->scm, true);
1383 if (err < 0)
1384 return err;
1385
1386 if (msg->msg_namelen) {
1387 err = -EINVAL;
1388 if (addr->nl_family != AF_NETLINK)
1389 goto out;
1390 dst_portid = addr->nl_pid;
1391 dst_group = ffs(addr->nl_groups);
1392 err = -EPERM;
1393 if ((dst_group || dst_portid) &&
1394 !netlink_capable(sock, NL_CFG_F_NONROOT_SEND))
1395 goto out;
1396 } else {
1397 dst_portid = nlk->dst_portid;
1398 dst_group = nlk->dst_group;
1399 }
1400
1401 if (!nlk->portid) {
1402 err = netlink_autobind(sock);
1403 if (err)
1404 goto out;
1405 }
1406
1407 err = -EMSGSIZE;
1408 if (len > sk->sk_sndbuf - 32)
1409 goto out;
1410 err = -ENOBUFS;
1411 skb = alloc_skb(len, GFP_KERNEL);
1412 if (skb == NULL)
1413 goto out;
1414
1415 NETLINK_CB(skb).portid = nlk->portid;
1416 NETLINK_CB(skb).dst_group = dst_group;
1417 NETLINK_CB(skb).creds = siocb->scm->creds;
1418
1419 err = -EFAULT;
1420 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1421 kfree_skb(skb);
1422 goto out;
1423 }
1424
1425 err = security_netlink_send(sk, skb);
1426 if (err) {
1427 kfree_skb(skb);
1428 goto out;
1429 }
1430
1431 if (dst_group) {
1432 atomic_inc(&skb->users);
1433 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1434 }
1435 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1436
1437 out:
1438 scm_destroy(siocb->scm);
1439 return err;
1440 }
1441
1442 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1443 struct msghdr *msg, size_t len,
1444 int flags)
1445 {
1446 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1447 struct scm_cookie scm;
1448 struct sock *sk = sock->sk;
1449 struct netlink_sock *nlk = nlk_sk(sk);
1450 int noblock = flags&MSG_DONTWAIT;
1451 size_t copied;
1452 struct sk_buff *skb, *data_skb;
1453 int err, ret;
1454
1455 if (flags&MSG_OOB)
1456 return -EOPNOTSUPP;
1457
1458 copied = 0;
1459
1460 skb = skb_recv_datagram(sk, flags, noblock, &err);
1461 if (skb == NULL)
1462 goto out;
1463
1464 data_skb = skb;
1465
1466 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1467 if (unlikely(skb_shinfo(skb)->frag_list)) {
1468 /*
1469 * If this skb has a frag_list, then here that means that we
1470 * will have to use the frag_list skb's data for compat tasks
1471 * and the regular skb's data for normal (non-compat) tasks.
1472 *
1473 * If we need to send the compat skb, assign it to the
1474 * 'data_skb' variable so that it will be used below for data
1475 * copying. We keep 'skb' for everything else, including
1476 * freeing both later.
1477 */
1478 if (flags & MSG_CMSG_COMPAT)
1479 data_skb = skb_shinfo(skb)->frag_list;
1480 }
1481 #endif
1482
1483 msg->msg_namelen = 0;
1484
1485 copied = data_skb->len;
1486 if (len < copied) {
1487 msg->msg_flags |= MSG_TRUNC;
1488 copied = len;
1489 }
1490
1491 skb_reset_transport_header(data_skb);
1492 err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
1493
1494 if (msg->msg_name) {
1495 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1496 addr->nl_family = AF_NETLINK;
1497 addr->nl_pad = 0;
1498 addr->nl_pid = NETLINK_CB(skb).portid;
1499 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1500 msg->msg_namelen = sizeof(*addr);
1501 }
1502
1503 if (nlk->flags & NETLINK_RECV_PKTINFO)
1504 netlink_cmsg_recv_pktinfo(msg, skb);
1505
1506 if (NULL == siocb->scm) {
1507 memset(&scm, 0, sizeof(scm));
1508 siocb->scm = &scm;
1509 }
1510 siocb->scm->creds = *NETLINK_CREDS(skb);
1511 if (flags & MSG_TRUNC)
1512 copied = data_skb->len;
1513
1514 skb_free_datagram(sk, skb);
1515
1516 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1517 ret = netlink_dump(sk);
1518 if (ret) {
1519 sk->sk_err = ret;
1520 sk->sk_error_report(sk);
1521 }
1522 }
1523
1524 scm_recv(sock, msg, siocb->scm, flags);
1525 out:
1526 netlink_rcv_wake(sk);
1527 return err ? : copied;
1528 }
1529
1530 static void netlink_data_ready(struct sock *sk, int len)
1531 {
1532 BUG();
1533 }
1534
1535 /*
1536 * We export these functions to other modules. They provide a
1537 * complete set of kernel non-blocking support for message
1538 * queueing.
1539 */
1540
1541 struct sock *
1542 __netlink_kernel_create(struct net *net, int unit, struct module *module,
1543 struct netlink_kernel_cfg *cfg)
1544 {
1545 struct socket *sock;
1546 struct sock *sk;
1547 struct netlink_sock *nlk;
1548 struct listeners *listeners = NULL;
1549 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
1550 unsigned int groups;
1551
1552 BUG_ON(!nl_table);
1553
1554 if (unit < 0 || unit >= MAX_LINKS)
1555 return NULL;
1556
1557 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1558 return NULL;
1559
1560 /*
1561 * We have to just have a reference on the net from sk, but don't
1562 * get_net it. Besides, we cannot get and then put the net here.
1563 * So we create one inside init_net and the move it to net.
1564 */
1565
1566 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1567 goto out_sock_release_nosk;
1568
1569 sk = sock->sk;
1570 sk_change_net(sk, net);
1571
1572 if (!cfg || cfg->groups < 32)
1573 groups = 32;
1574 else
1575 groups = cfg->groups;
1576
1577 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
1578 if (!listeners)
1579 goto out_sock_release;
1580
1581 sk->sk_data_ready = netlink_data_ready;
1582 if (cfg && cfg->input)
1583 nlk_sk(sk)->netlink_rcv = cfg->input;
1584
1585 if (netlink_insert(sk, net, 0))
1586 goto out_sock_release;
1587
1588 nlk = nlk_sk(sk);
1589 nlk->flags |= NETLINK_KERNEL_SOCKET;
1590
1591 netlink_table_grab();
1592 if (!nl_table[unit].registered) {
1593 nl_table[unit].groups = groups;
1594 rcu_assign_pointer(nl_table[unit].listeners, listeners);
1595 nl_table[unit].cb_mutex = cb_mutex;
1596 nl_table[unit].module = module;
1597 if (cfg) {
1598 nl_table[unit].bind = cfg->bind;
1599 nl_table[unit].flags = cfg->flags;
1600 }
1601 nl_table[unit].registered = 1;
1602 } else {
1603 kfree(listeners);
1604 nl_table[unit].registered++;
1605 }
1606 netlink_table_ungrab();
1607 return sk;
1608
1609 out_sock_release:
1610 kfree(listeners);
1611 netlink_kernel_release(sk);
1612 return NULL;
1613
1614 out_sock_release_nosk:
1615 sock_release(sock);
1616 return NULL;
1617 }
1618 EXPORT_SYMBOL(__netlink_kernel_create);
1619
1620 void
1621 netlink_kernel_release(struct sock *sk)
1622 {
1623 sk_release_kernel(sk);
1624 }
1625 EXPORT_SYMBOL(netlink_kernel_release);
1626
1627 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1628 {
1629 struct listeners *new, *old;
1630 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1631
1632 if (groups < 32)
1633 groups = 32;
1634
1635 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1636 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
1637 if (!new)
1638 return -ENOMEM;
1639 old = nl_deref_protected(tbl->listeners);
1640 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
1641 rcu_assign_pointer(tbl->listeners, new);
1642
1643 kfree_rcu(old, rcu);
1644 }
1645 tbl->groups = groups;
1646
1647 return 0;
1648 }
1649
1650 /**
1651 * netlink_change_ngroups - change number of multicast groups
1652 *
1653 * This changes the number of multicast groups that are available
1654 * on a certain netlink family. Note that it is not possible to
1655 * change the number of groups to below 32. Also note that it does
1656 * not implicitly call netlink_clear_multicast_users() when the
1657 * number of groups is reduced.
1658 *
1659 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1660 * @groups: The new number of groups.
1661 */
1662 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1663 {
1664 int err;
1665
1666 netlink_table_grab();
1667 err = __netlink_change_ngroups(sk, groups);
1668 netlink_table_ungrab();
1669
1670 return err;
1671 }
1672
1673 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1674 {
1675 struct sock *sk;
1676 struct hlist_node *node;
1677 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1678
1679 sk_for_each_bound(sk, node, &tbl->mc_list)
1680 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1681 }
1682
1683 /**
1684 * netlink_clear_multicast_users - kick off multicast listeners
1685 *
1686 * This function removes all listeners from the given group.
1687 * @ksk: The kernel netlink socket, as returned by
1688 * netlink_kernel_create().
1689 * @group: The multicast group to clear.
1690 */
1691 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1692 {
1693 netlink_table_grab();
1694 __netlink_clear_multicast_users(ksk, group);
1695 netlink_table_ungrab();
1696 }
1697
1698 struct nlmsghdr *
1699 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
1700 {
1701 struct nlmsghdr *nlh;
1702 int size = NLMSG_LENGTH(len);
1703
1704 nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
1705 nlh->nlmsg_type = type;
1706 nlh->nlmsg_len = size;
1707 nlh->nlmsg_flags = flags;
1708 nlh->nlmsg_pid = portid;
1709 nlh->nlmsg_seq = seq;
1710 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
1711 memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size);
1712 return nlh;
1713 }
1714 EXPORT_SYMBOL(__nlmsg_put);
1715
1716 /*
1717 * It looks a bit ugly.
1718 * It would be better to create kernel thread.
1719 */
1720
1721 static int netlink_dump(struct sock *sk)
1722 {
1723 struct netlink_sock *nlk = nlk_sk(sk);
1724 struct netlink_callback *cb;
1725 struct sk_buff *skb = NULL;
1726 struct nlmsghdr *nlh;
1727 int len, err = -ENOBUFS;
1728 int alloc_size;
1729
1730 mutex_lock(nlk->cb_mutex);
1731
1732 cb = nlk->cb;
1733 if (cb == NULL) {
1734 err = -EINVAL;
1735 goto errout_skb;
1736 }
1737
1738 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
1739
1740 skb = sock_rmalloc(sk, alloc_size, 0, GFP_KERNEL);
1741 if (!skb)
1742 goto errout_skb;
1743
1744 len = cb->dump(skb, cb);
1745
1746 if (len > 0) {
1747 mutex_unlock(nlk->cb_mutex);
1748
1749 if (sk_filter(sk, skb))
1750 kfree_skb(skb);
1751 else
1752 __netlink_sendskb(sk, skb);
1753 return 0;
1754 }
1755
1756 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1757 if (!nlh)
1758 goto errout_skb;
1759
1760 nl_dump_check_consistent(cb, nlh);
1761
1762 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1763
1764 if (sk_filter(sk, skb))
1765 kfree_skb(skb);
1766 else
1767 __netlink_sendskb(sk, skb);
1768
1769 if (cb->done)
1770 cb->done(cb);
1771 nlk->cb = NULL;
1772 mutex_unlock(nlk->cb_mutex);
1773
1774 module_put(cb->module);
1775 netlink_consume_callback(cb);
1776 return 0;
1777
1778 errout_skb:
1779 mutex_unlock(nlk->cb_mutex);
1780 kfree_skb(skb);
1781 return err;
1782 }
1783
1784 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1785 const struct nlmsghdr *nlh,
1786 struct netlink_dump_control *control)
1787 {
1788 struct netlink_callback *cb;
1789 struct sock *sk;
1790 struct netlink_sock *nlk;
1791 int ret;
1792
1793 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1794 if (cb == NULL)
1795 return -ENOBUFS;
1796
1797 cb->dump = control->dump;
1798 cb->done = control->done;
1799 cb->nlh = nlh;
1800 cb->data = control->data;
1801 cb->module = control->module;
1802 cb->min_dump_alloc = control->min_dump_alloc;
1803 atomic_inc(&skb->users);
1804 cb->skb = skb;
1805
1806 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
1807 if (sk == NULL) {
1808 netlink_destroy_callback(cb);
1809 return -ECONNREFUSED;
1810 }
1811 nlk = nlk_sk(sk);
1812
1813 mutex_lock(nlk->cb_mutex);
1814 /* A dump is in progress... */
1815 if (nlk->cb) {
1816 mutex_unlock(nlk->cb_mutex);
1817 netlink_destroy_callback(cb);
1818 ret = -EBUSY;
1819 goto out;
1820 }
1821 /* add reference of module which cb->dump belongs to */
1822 if (!try_module_get(cb->module)) {
1823 mutex_unlock(nlk->cb_mutex);
1824 netlink_destroy_callback(cb);
1825 ret = -EPROTONOSUPPORT;
1826 goto out;
1827 }
1828
1829 nlk->cb = cb;
1830 mutex_unlock(nlk->cb_mutex);
1831
1832 ret = netlink_dump(sk);
1833 out:
1834 sock_put(sk);
1835
1836 if (ret)
1837 return ret;
1838
1839 /* We successfully started a dump, by returning -EINTR we
1840 * signal not to send ACK even if it was requested.
1841 */
1842 return -EINTR;
1843 }
1844 EXPORT_SYMBOL(__netlink_dump_start);
1845
1846 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1847 {
1848 struct sk_buff *skb;
1849 struct nlmsghdr *rep;
1850 struct nlmsgerr *errmsg;
1851 size_t payload = sizeof(*errmsg);
1852
1853 /* error messages get the original request appened */
1854 if (err)
1855 payload += nlmsg_len(nlh);
1856
1857 skb = nlmsg_new(payload, GFP_KERNEL);
1858 if (!skb) {
1859 struct sock *sk;
1860
1861 sk = netlink_lookup(sock_net(in_skb->sk),
1862 in_skb->sk->sk_protocol,
1863 NETLINK_CB(in_skb).portid);
1864 if (sk) {
1865 sk->sk_err = ENOBUFS;
1866 sk->sk_error_report(sk);
1867 sock_put(sk);
1868 }
1869 return;
1870 }
1871
1872 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
1873 NLMSG_ERROR, payload, 0);
1874 errmsg = nlmsg_data(rep);
1875 errmsg->error = err;
1876 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1877 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
1878 }
1879 EXPORT_SYMBOL(netlink_ack);
1880
1881 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1882 struct nlmsghdr *))
1883 {
1884 struct nlmsghdr *nlh;
1885 int err;
1886
1887 while (skb->len >= nlmsg_total_size(0)) {
1888 int msglen;
1889
1890 nlh = nlmsg_hdr(skb);
1891 err = 0;
1892
1893 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1894 return 0;
1895
1896 /* Only requests are handled by the kernel */
1897 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1898 goto ack;
1899
1900 /* Skip control messages */
1901 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1902 goto ack;
1903
1904 err = cb(skb, nlh);
1905 if (err == -EINTR)
1906 goto skip;
1907
1908 ack:
1909 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1910 netlink_ack(skb, nlh, err);
1911
1912 skip:
1913 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1914 if (msglen > skb->len)
1915 msglen = skb->len;
1916 skb_pull(skb, msglen);
1917 }
1918
1919 return 0;
1920 }
1921 EXPORT_SYMBOL(netlink_rcv_skb);
1922
1923 /**
1924 * nlmsg_notify - send a notification netlink message
1925 * @sk: netlink socket to use
1926 * @skb: notification message
1927 * @portid: destination netlink portid for reports or 0
1928 * @group: destination multicast group or 0
1929 * @report: 1 to report back, 0 to disable
1930 * @flags: allocation flags
1931 */
1932 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
1933 unsigned int group, int report, gfp_t flags)
1934 {
1935 int err = 0;
1936
1937 if (group) {
1938 int exclude_portid = 0;
1939
1940 if (report) {
1941 atomic_inc(&skb->users);
1942 exclude_portid = portid;
1943 }
1944
1945 /* errors reported via destination sk->sk_err, but propagate
1946 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1947 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
1948 }
1949
1950 if (report) {
1951 int err2;
1952
1953 err2 = nlmsg_unicast(sk, skb, portid);
1954 if (!err || err == -ESRCH)
1955 err = err2;
1956 }
1957
1958 return err;
1959 }
1960 EXPORT_SYMBOL(nlmsg_notify);
1961
1962 #ifdef CONFIG_PROC_FS
1963 struct nl_seq_iter {
1964 struct seq_net_private p;
1965 int link;
1966 int hash_idx;
1967 };
1968
1969 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1970 {
1971 struct nl_seq_iter *iter = seq->private;
1972 int i, j;
1973 struct sock *s;
1974 struct hlist_node *node;
1975 loff_t off = 0;
1976
1977 for (i = 0; i < MAX_LINKS; i++) {
1978 struct nl_portid_hash *hash = &nl_table[i].hash;
1979
1980 for (j = 0; j <= hash->mask; j++) {
1981 sk_for_each(s, node, &hash->table[j]) {
1982 if (sock_net(s) != seq_file_net(seq))
1983 continue;
1984 if (off == pos) {
1985 iter->link = i;
1986 iter->hash_idx = j;
1987 return s;
1988 }
1989 ++off;
1990 }
1991 }
1992 }
1993 return NULL;
1994 }
1995
1996 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1997 __acquires(nl_table_lock)
1998 {
1999 read_lock(&nl_table_lock);
2000 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2001 }
2002
2003 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2004 {
2005 struct sock *s;
2006 struct nl_seq_iter *iter;
2007 int i, j;
2008
2009 ++*pos;
2010
2011 if (v == SEQ_START_TOKEN)
2012 return netlink_seq_socket_idx(seq, 0);
2013
2014 iter = seq->private;
2015 s = v;
2016 do {
2017 s = sk_next(s);
2018 } while (s && sock_net(s) != seq_file_net(seq));
2019 if (s)
2020 return s;
2021
2022 i = iter->link;
2023 j = iter->hash_idx + 1;
2024
2025 do {
2026 struct nl_portid_hash *hash = &nl_table[i].hash;
2027
2028 for (; j <= hash->mask; j++) {
2029 s = sk_head(&hash->table[j]);
2030 while (s && sock_net(s) != seq_file_net(seq))
2031 s = sk_next(s);
2032 if (s) {
2033 iter->link = i;
2034 iter->hash_idx = j;
2035 return s;
2036 }
2037 }
2038
2039 j = 0;
2040 } while (++i < MAX_LINKS);
2041
2042 return NULL;
2043 }
2044
2045 static void netlink_seq_stop(struct seq_file *seq, void *v)
2046 __releases(nl_table_lock)
2047 {
2048 read_unlock(&nl_table_lock);
2049 }
2050
2051
2052 static int netlink_seq_show(struct seq_file *seq, void *v)
2053 {
2054 if (v == SEQ_START_TOKEN) {
2055 seq_puts(seq,
2056 "sk Eth Pid Groups "
2057 "Rmem Wmem Dump Locks Drops Inode\n");
2058 } else {
2059 struct sock *s = v;
2060 struct netlink_sock *nlk = nlk_sk(s);
2061
2062 seq_printf(seq, "%pK %-3d %-6d %08x %-8d %-8d %pK %-8d %-8d %-8lu\n",
2063 s,
2064 s->sk_protocol,
2065 nlk->portid,
2066 nlk->groups ? (u32)nlk->groups[0] : 0,
2067 sk_rmem_alloc_get(s),
2068 sk_wmem_alloc_get(s),
2069 nlk->cb,
2070 atomic_read(&s->sk_refcnt),
2071 atomic_read(&s->sk_drops),
2072 sock_i_ino(s)
2073 );
2074
2075 }
2076 return 0;
2077 }
2078
2079 static const struct seq_operations netlink_seq_ops = {
2080 .start = netlink_seq_start,
2081 .next = netlink_seq_next,
2082 .stop = netlink_seq_stop,
2083 .show = netlink_seq_show,
2084 };
2085
2086
2087 static int netlink_seq_open(struct inode *inode, struct file *file)
2088 {
2089 return seq_open_net(inode, file, &netlink_seq_ops,
2090 sizeof(struct nl_seq_iter));
2091 }
2092
2093 static const struct file_operations netlink_seq_fops = {
2094 .owner = THIS_MODULE,
2095 .open = netlink_seq_open,
2096 .read = seq_read,
2097 .llseek = seq_lseek,
2098 .release = seq_release_net,
2099 };
2100
2101 #endif
2102
2103 int netlink_register_notifier(struct notifier_block *nb)
2104 {
2105 return atomic_notifier_chain_register(&netlink_chain, nb);
2106 }
2107 EXPORT_SYMBOL(netlink_register_notifier);
2108
2109 int netlink_unregister_notifier(struct notifier_block *nb)
2110 {
2111 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2112 }
2113 EXPORT_SYMBOL(netlink_unregister_notifier);
2114
2115 static const struct proto_ops netlink_ops = {
2116 .family = PF_NETLINK,
2117 .owner = THIS_MODULE,
2118 .release = netlink_release,
2119 .bind = netlink_bind,
2120 .connect = netlink_connect,
2121 .socketpair = sock_no_socketpair,
2122 .accept = sock_no_accept,
2123 .getname = netlink_getname,
2124 .poll = datagram_poll,
2125 .ioctl = sock_no_ioctl,
2126 .listen = sock_no_listen,
2127 .shutdown = sock_no_shutdown,
2128 .setsockopt = netlink_setsockopt,
2129 .getsockopt = netlink_getsockopt,
2130 .sendmsg = netlink_sendmsg,
2131 .recvmsg = netlink_recvmsg,
2132 .mmap = sock_no_mmap,
2133 .sendpage = sock_no_sendpage,
2134 };
2135
2136 static const struct net_proto_family netlink_family_ops = {
2137 .family = PF_NETLINK,
2138 .create = netlink_create,
2139 .owner = THIS_MODULE, /* for consistency 8) */
2140 };
2141
2142 static int __net_init netlink_net_init(struct net *net)
2143 {
2144 #ifdef CONFIG_PROC_FS
2145 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2146 return -ENOMEM;
2147 #endif
2148 return 0;
2149 }
2150
2151 static void __net_exit netlink_net_exit(struct net *net)
2152 {
2153 #ifdef CONFIG_PROC_FS
2154 proc_net_remove(net, "netlink");
2155 #endif
2156 }
2157
2158 static void __init netlink_add_usersock_entry(void)
2159 {
2160 struct listeners *listeners;
2161 int groups = 32;
2162
2163 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2164 if (!listeners)
2165 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2166
2167 netlink_table_grab();
2168
2169 nl_table[NETLINK_USERSOCK].groups = groups;
2170 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2171 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2172 nl_table[NETLINK_USERSOCK].registered = 1;
2173 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2174
2175 netlink_table_ungrab();
2176 }
2177
2178 static struct pernet_operations __net_initdata netlink_net_ops = {
2179 .init = netlink_net_init,
2180 .exit = netlink_net_exit,
2181 };
2182
2183 static int __init netlink_proto_init(void)
2184 {
2185 struct sk_buff *dummy_skb;
2186 int i;
2187 unsigned long limit;
2188 unsigned int order;
2189 int err = proto_register(&netlink_proto, 0);
2190
2191 if (err != 0)
2192 goto out;
2193
2194 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2195
2196 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2197 if (!nl_table)
2198 goto panic;
2199
2200 if (totalram_pages >= (128 * 1024))
2201 limit = totalram_pages >> (21 - PAGE_SHIFT);
2202 else
2203 limit = totalram_pages >> (23 - PAGE_SHIFT);
2204
2205 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2206 limit = (1UL << order) / sizeof(struct hlist_head);
2207 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2208
2209 for (i = 0; i < MAX_LINKS; i++) {
2210 struct nl_portid_hash *hash = &nl_table[i].hash;
2211
2212 hash->table = nl_portid_hash_zalloc(1 * sizeof(*hash->table));
2213 if (!hash->table) {
2214 while (i-- > 0)
2215 nl_portid_hash_free(nl_table[i].hash.table,
2216 1 * sizeof(*hash->table));
2217 kfree(nl_table);
2218 goto panic;
2219 }
2220 hash->max_shift = order;
2221 hash->shift = 0;
2222 hash->mask = 0;
2223 hash->rehash_time = jiffies;
2224 }
2225
2226 netlink_add_usersock_entry();
2227
2228 sock_register(&netlink_family_ops);
2229 register_pernet_subsys(&netlink_net_ops);
2230 /* The netlink device handler may be needed early. */
2231 rtnetlink_init();
2232 out:
2233 return err;
2234 panic:
2235 panic("netlink_init: Cannot allocate nl_table\n");
2236 }
2237
2238 core_initcall(netlink_proto_init);
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