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[GitHub/LineageOS/android_kernel_samsung_universal7580.git] / net / netlink / af_netlink.c
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 ns_capable(sock_net(sock->sk)->user_ns, 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 (addr_len < sizeof(struct sockaddr_nl))
673 return -EINVAL;
674
675 if (nladdr->nl_family != AF_NETLINK)
676 return -EINVAL;
677
678 /* Only superuser is allowed to listen multicasts */
679 if (nladdr->nl_groups) {
680 if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV))
681 return -EPERM;
682 err = netlink_realloc_groups(sk);
683 if (err)
684 return err;
685 }
686
687 if (nlk->portid) {
688 if (nladdr->nl_pid != nlk->portid)
689 return -EINVAL;
690 } else {
691 err = nladdr->nl_pid ?
692 netlink_insert(sk, net, nladdr->nl_pid) :
693 netlink_autobind(sock);
694 if (err)
695 return err;
696 }
697
698 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
699 return 0;
700
701 netlink_table_grab();
702 netlink_update_subscriptions(sk, nlk->subscriptions +
703 hweight32(nladdr->nl_groups) -
704 hweight32(nlk->groups[0]));
705 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
706 netlink_update_listeners(sk);
707 netlink_table_ungrab();
708
709 if (nlk->netlink_bind && nlk->groups[0]) {
710 int i;
711
712 for (i=0; i<nlk->ngroups; i++) {
713 if (test_bit(i, nlk->groups))
714 nlk->netlink_bind(i);
715 }
716 }
717
718 return 0;
719 }
720
721 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
722 int alen, int flags)
723 {
724 int err = 0;
725 struct sock *sk = sock->sk;
726 struct netlink_sock *nlk = nlk_sk(sk);
727 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
728
729 if (alen < sizeof(addr->sa_family))
730 return -EINVAL;
731
732 if (addr->sa_family == AF_UNSPEC) {
733 sk->sk_state = NETLINK_UNCONNECTED;
734 nlk->dst_portid = 0;
735 nlk->dst_group = 0;
736 return 0;
737 }
738 if (addr->sa_family != AF_NETLINK)
739 return -EINVAL;
740
741 /* Only superuser is allowed to send multicasts */
742 if (nladdr->nl_groups && !netlink_capable(sock, NL_CFG_F_NONROOT_SEND))
743 return -EPERM;
744
745 if (!nlk->portid)
746 err = netlink_autobind(sock);
747
748 if (err == 0) {
749 sk->sk_state = NETLINK_CONNECTED;
750 nlk->dst_portid = nladdr->nl_pid;
751 nlk->dst_group = ffs(nladdr->nl_groups);
752 }
753
754 return err;
755 }
756
757 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
758 int *addr_len, int peer)
759 {
760 struct sock *sk = sock->sk;
761 struct netlink_sock *nlk = nlk_sk(sk);
762 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
763
764 nladdr->nl_family = AF_NETLINK;
765 nladdr->nl_pad = 0;
766 *addr_len = sizeof(*nladdr);
767
768 if (peer) {
769 nladdr->nl_pid = nlk->dst_portid;
770 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
771 } else {
772 nladdr->nl_pid = nlk->portid;
773 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
774 }
775 return 0;
776 }
777
778 static void netlink_overrun(struct sock *sk)
779 {
780 struct netlink_sock *nlk = nlk_sk(sk);
781
782 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
783 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
784 sk->sk_err = ENOBUFS;
785 sk->sk_error_report(sk);
786 }
787 }
788 atomic_inc(&sk->sk_drops);
789 }
790
791 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
792 {
793 struct sock *sock;
794 struct netlink_sock *nlk;
795
796 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
797 if (!sock)
798 return ERR_PTR(-ECONNREFUSED);
799
800 /* Don't bother queuing skb if kernel socket has no input function */
801 nlk = nlk_sk(sock);
802 if (sock->sk_state == NETLINK_CONNECTED &&
803 nlk->dst_portid != nlk_sk(ssk)->portid) {
804 sock_put(sock);
805 return ERR_PTR(-ECONNREFUSED);
806 }
807 return sock;
808 }
809
810 struct sock *netlink_getsockbyfilp(struct file *filp)
811 {
812 struct inode *inode = file_inode(filp);
813 struct sock *sock;
814
815 if (!S_ISSOCK(inode->i_mode))
816 return ERR_PTR(-ENOTSOCK);
817
818 sock = SOCKET_I(inode)->sk;
819 if (sock->sk_family != AF_NETLINK)
820 return ERR_PTR(-EINVAL);
821
822 sock_hold(sock);
823 return sock;
824 }
825
826 /*
827 * Attach a skb to a netlink socket.
828 * The caller must hold a reference to the destination socket. On error, the
829 * reference is dropped. The skb is not send to the destination, just all
830 * all error checks are performed and memory in the queue is reserved.
831 * Return values:
832 * < 0: error. skb freed, reference to sock dropped.
833 * 0: continue
834 * 1: repeat lookup - reference dropped while waiting for socket memory.
835 */
836 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
837 long *timeo, struct sock *ssk)
838 {
839 struct netlink_sock *nlk;
840
841 nlk = nlk_sk(sk);
842
843 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
844 test_bit(0, &nlk->state)) {
845 DECLARE_WAITQUEUE(wait, current);
846 if (!*timeo) {
847 if (!ssk || netlink_is_kernel(ssk))
848 netlink_overrun(sk);
849 sock_put(sk);
850 kfree_skb(skb);
851 return -EAGAIN;
852 }
853
854 __set_current_state(TASK_INTERRUPTIBLE);
855 add_wait_queue(&nlk->wait, &wait);
856
857 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
858 test_bit(0, &nlk->state)) &&
859 !sock_flag(sk, SOCK_DEAD))
860 *timeo = schedule_timeout(*timeo);
861
862 __set_current_state(TASK_RUNNING);
863 remove_wait_queue(&nlk->wait, &wait);
864 sock_put(sk);
865
866 if (signal_pending(current)) {
867 kfree_skb(skb);
868 return sock_intr_errno(*timeo);
869 }
870 return 1;
871 }
872 skb_set_owner_r(skb, sk);
873 return 0;
874 }
875
876 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
877 {
878 int len = skb->len;
879
880 skb_queue_tail(&sk->sk_receive_queue, skb);
881 sk->sk_data_ready(sk, len);
882 return len;
883 }
884
885 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
886 {
887 int len = __netlink_sendskb(sk, skb);
888
889 sock_put(sk);
890 return len;
891 }
892
893 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
894 {
895 kfree_skb(skb);
896 sock_put(sk);
897 }
898
899 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
900 {
901 int delta;
902
903 skb_orphan(skb);
904
905 delta = skb->end - skb->tail;
906 if (delta * 2 < skb->truesize)
907 return skb;
908
909 if (skb_shared(skb)) {
910 struct sk_buff *nskb = skb_clone(skb, allocation);
911 if (!nskb)
912 return skb;
913 consume_skb(skb);
914 skb = nskb;
915 }
916
917 if (!pskb_expand_head(skb, 0, -delta, allocation))
918 skb->truesize -= delta;
919
920 return skb;
921 }
922
923 static void netlink_rcv_wake(struct sock *sk)
924 {
925 struct netlink_sock *nlk = nlk_sk(sk);
926
927 if (skb_queue_empty(&sk->sk_receive_queue))
928 clear_bit(0, &nlk->state);
929 if (!test_bit(0, &nlk->state))
930 wake_up_interruptible(&nlk->wait);
931 }
932
933 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
934 struct sock *ssk)
935 {
936 int ret;
937 struct netlink_sock *nlk = nlk_sk(sk);
938
939 ret = -ECONNREFUSED;
940 if (nlk->netlink_rcv != NULL) {
941 ret = skb->len;
942 skb_set_owner_r(skb, sk);
943 NETLINK_CB(skb).ssk = ssk;
944 nlk->netlink_rcv(skb);
945 consume_skb(skb);
946 } else {
947 kfree_skb(skb);
948 }
949 sock_put(sk);
950 return ret;
951 }
952
953 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
954 u32 portid, int nonblock)
955 {
956 struct sock *sk;
957 int err;
958 long timeo;
959
960 skb = netlink_trim(skb, gfp_any());
961
962 timeo = sock_sndtimeo(ssk, nonblock);
963 retry:
964 sk = netlink_getsockbyportid(ssk, portid);
965 if (IS_ERR(sk)) {
966 kfree_skb(skb);
967 return PTR_ERR(sk);
968 }
969 if (netlink_is_kernel(sk))
970 return netlink_unicast_kernel(sk, skb, ssk);
971
972 if (sk_filter(sk, skb)) {
973 err = skb->len;
974 kfree_skb(skb);
975 sock_put(sk);
976 return err;
977 }
978
979 err = netlink_attachskb(sk, skb, &timeo, ssk);
980 if (err == 1)
981 goto retry;
982 if (err)
983 return err;
984
985 return netlink_sendskb(sk, skb);
986 }
987 EXPORT_SYMBOL(netlink_unicast);
988
989 int netlink_has_listeners(struct sock *sk, unsigned int group)
990 {
991 int res = 0;
992 struct listeners *listeners;
993
994 BUG_ON(!netlink_is_kernel(sk));
995
996 rcu_read_lock();
997 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
998
999 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1000 res = test_bit(group - 1, listeners->masks);
1001
1002 rcu_read_unlock();
1003
1004 return res;
1005 }
1006 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1007
1008 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1009 {
1010 struct netlink_sock *nlk = nlk_sk(sk);
1011
1012 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1013 !test_bit(0, &nlk->state)) {
1014 skb_set_owner_r(skb, sk);
1015 __netlink_sendskb(sk, skb);
1016 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1017 }
1018 return -1;
1019 }
1020
1021 struct netlink_broadcast_data {
1022 struct sock *exclude_sk;
1023 struct net *net;
1024 u32 portid;
1025 u32 group;
1026 int failure;
1027 int delivery_failure;
1028 int congested;
1029 int delivered;
1030 gfp_t allocation;
1031 struct sk_buff *skb, *skb2;
1032 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1033 void *tx_data;
1034 };
1035
1036 static int do_one_broadcast(struct sock *sk,
1037 struct netlink_broadcast_data *p)
1038 {
1039 struct netlink_sock *nlk = nlk_sk(sk);
1040 int val;
1041
1042 if (p->exclude_sk == sk)
1043 goto out;
1044
1045 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1046 !test_bit(p->group - 1, nlk->groups))
1047 goto out;
1048
1049 if (!net_eq(sock_net(sk), p->net))
1050 goto out;
1051
1052 if (p->failure) {
1053 netlink_overrun(sk);
1054 goto out;
1055 }
1056
1057 sock_hold(sk);
1058 if (p->skb2 == NULL) {
1059 if (skb_shared(p->skb)) {
1060 p->skb2 = skb_clone(p->skb, p->allocation);
1061 } else {
1062 p->skb2 = skb_get(p->skb);
1063 /*
1064 * skb ownership may have been set when
1065 * delivered to a previous socket.
1066 */
1067 skb_orphan(p->skb2);
1068 }
1069 }
1070 if (p->skb2 == NULL) {
1071 netlink_overrun(sk);
1072 /* Clone failed. Notify ALL listeners. */
1073 p->failure = 1;
1074 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1075 p->delivery_failure = 1;
1076 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1077 kfree_skb(p->skb2);
1078 p->skb2 = NULL;
1079 } else if (sk_filter(sk, p->skb2)) {
1080 kfree_skb(p->skb2);
1081 p->skb2 = NULL;
1082 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1083 netlink_overrun(sk);
1084 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1085 p->delivery_failure = 1;
1086 } else {
1087 p->congested |= val;
1088 p->delivered = 1;
1089 p->skb2 = NULL;
1090 }
1091 sock_put(sk);
1092
1093 out:
1094 return 0;
1095 }
1096
1097 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1098 u32 group, gfp_t allocation,
1099 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1100 void *filter_data)
1101 {
1102 struct net *net = sock_net(ssk);
1103 struct netlink_broadcast_data info;
1104 struct hlist_node *node;
1105 struct sock *sk;
1106
1107 skb = netlink_trim(skb, allocation);
1108
1109 info.exclude_sk = ssk;
1110 info.net = net;
1111 info.portid = portid;
1112 info.group = group;
1113 info.failure = 0;
1114 info.delivery_failure = 0;
1115 info.congested = 0;
1116 info.delivered = 0;
1117 info.allocation = allocation;
1118 info.skb = skb;
1119 info.skb2 = NULL;
1120 info.tx_filter = filter;
1121 info.tx_data = filter_data;
1122
1123 /* While we sleep in clone, do not allow to change socket list */
1124
1125 netlink_lock_table();
1126
1127 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1128 do_one_broadcast(sk, &info);
1129
1130 consume_skb(skb);
1131
1132 netlink_unlock_table();
1133
1134 if (info.delivery_failure) {
1135 kfree_skb(info.skb2);
1136 return -ENOBUFS;
1137 }
1138 consume_skb(info.skb2);
1139
1140 if (info.delivered) {
1141 if (info.congested && (allocation & __GFP_WAIT))
1142 yield();
1143 return 0;
1144 }
1145 return -ESRCH;
1146 }
1147 EXPORT_SYMBOL(netlink_broadcast_filtered);
1148
1149 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1150 u32 group, gfp_t allocation)
1151 {
1152 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1153 NULL, NULL);
1154 }
1155 EXPORT_SYMBOL(netlink_broadcast);
1156
1157 struct netlink_set_err_data {
1158 struct sock *exclude_sk;
1159 u32 portid;
1160 u32 group;
1161 int code;
1162 };
1163
1164 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1165 {
1166 struct netlink_sock *nlk = nlk_sk(sk);
1167 int ret = 0;
1168
1169 if (sk == p->exclude_sk)
1170 goto out;
1171
1172 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1173 goto out;
1174
1175 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1176 !test_bit(p->group - 1, nlk->groups))
1177 goto out;
1178
1179 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
1180 ret = 1;
1181 goto out;
1182 }
1183
1184 sk->sk_err = p->code;
1185 sk->sk_error_report(sk);
1186 out:
1187 return ret;
1188 }
1189
1190 /**
1191 * netlink_set_err - report error to broadcast listeners
1192 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1193 * @portid: the PORTID of a process that we want to skip (if any)
1194 * @groups: the broadcast group that will notice the error
1195 * @code: error code, must be negative (as usual in kernelspace)
1196 *
1197 * This function returns the number of broadcast listeners that have set the
1198 * NETLINK_RECV_NO_ENOBUFS socket option.
1199 */
1200 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
1201 {
1202 struct netlink_set_err_data info;
1203 struct hlist_node *node;
1204 struct sock *sk;
1205 int ret = 0;
1206
1207 info.exclude_sk = ssk;
1208 info.portid = portid;
1209 info.group = group;
1210 /* sk->sk_err wants a positive error value */
1211 info.code = -code;
1212
1213 read_lock(&nl_table_lock);
1214
1215 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1216 ret += do_one_set_err(sk, &info);
1217
1218 read_unlock(&nl_table_lock);
1219 return ret;
1220 }
1221 EXPORT_SYMBOL(netlink_set_err);
1222
1223 /* must be called with netlink table grabbed */
1224 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1225 unsigned int group,
1226 int is_new)
1227 {
1228 int old, new = !!is_new, subscriptions;
1229
1230 old = test_bit(group - 1, nlk->groups);
1231 subscriptions = nlk->subscriptions - old + new;
1232 if (new)
1233 __set_bit(group - 1, nlk->groups);
1234 else
1235 __clear_bit(group - 1, nlk->groups);
1236 netlink_update_subscriptions(&nlk->sk, subscriptions);
1237 netlink_update_listeners(&nlk->sk);
1238 }
1239
1240 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1241 char __user *optval, unsigned int optlen)
1242 {
1243 struct sock *sk = sock->sk;
1244 struct netlink_sock *nlk = nlk_sk(sk);
1245 unsigned int val = 0;
1246 int err;
1247
1248 if (level != SOL_NETLINK)
1249 return -ENOPROTOOPT;
1250
1251 if (optlen >= sizeof(int) &&
1252 get_user(val, (unsigned int __user *)optval))
1253 return -EFAULT;
1254
1255 switch (optname) {
1256 case NETLINK_PKTINFO:
1257 if (val)
1258 nlk->flags |= NETLINK_RECV_PKTINFO;
1259 else
1260 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1261 err = 0;
1262 break;
1263 case NETLINK_ADD_MEMBERSHIP:
1264 case NETLINK_DROP_MEMBERSHIP: {
1265 if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV))
1266 return -EPERM;
1267 err = netlink_realloc_groups(sk);
1268 if (err)
1269 return err;
1270 if (!val || val - 1 >= nlk->ngroups)
1271 return -EINVAL;
1272 netlink_table_grab();
1273 netlink_update_socket_mc(nlk, val,
1274 optname == NETLINK_ADD_MEMBERSHIP);
1275 netlink_table_ungrab();
1276
1277 if (nlk->netlink_bind)
1278 nlk->netlink_bind(val);
1279
1280 err = 0;
1281 break;
1282 }
1283 case NETLINK_BROADCAST_ERROR:
1284 if (val)
1285 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1286 else
1287 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1288 err = 0;
1289 break;
1290 case NETLINK_NO_ENOBUFS:
1291 if (val) {
1292 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1293 clear_bit(0, &nlk->state);
1294 wake_up_interruptible(&nlk->wait);
1295 } else {
1296 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1297 }
1298 err = 0;
1299 break;
1300 default:
1301 err = -ENOPROTOOPT;
1302 }
1303 return err;
1304 }
1305
1306 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1307 char __user *optval, int __user *optlen)
1308 {
1309 struct sock *sk = sock->sk;
1310 struct netlink_sock *nlk = nlk_sk(sk);
1311 int len, val, err;
1312
1313 if (level != SOL_NETLINK)
1314 return -ENOPROTOOPT;
1315
1316 if (get_user(len, optlen))
1317 return -EFAULT;
1318 if (len < 0)
1319 return -EINVAL;
1320
1321 switch (optname) {
1322 case NETLINK_PKTINFO:
1323 if (len < sizeof(int))
1324 return -EINVAL;
1325 len = sizeof(int);
1326 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1327 if (put_user(len, optlen) ||
1328 put_user(val, optval))
1329 return -EFAULT;
1330 err = 0;
1331 break;
1332 case NETLINK_BROADCAST_ERROR:
1333 if (len < sizeof(int))
1334 return -EINVAL;
1335 len = sizeof(int);
1336 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1337 if (put_user(len, optlen) ||
1338 put_user(val, optval))
1339 return -EFAULT;
1340 err = 0;
1341 break;
1342 case NETLINK_NO_ENOBUFS:
1343 if (len < sizeof(int))
1344 return -EINVAL;
1345 len = sizeof(int);
1346 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1347 if (put_user(len, optlen) ||
1348 put_user(val, optval))
1349 return -EFAULT;
1350 err = 0;
1351 break;
1352 default:
1353 err = -ENOPROTOOPT;
1354 }
1355 return err;
1356 }
1357
1358 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1359 {
1360 struct nl_pktinfo info;
1361
1362 info.group = NETLINK_CB(skb).dst_group;
1363 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1364 }
1365
1366 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1367 struct msghdr *msg, size_t len)
1368 {
1369 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1370 struct sock *sk = sock->sk;
1371 struct netlink_sock *nlk = nlk_sk(sk);
1372 struct sockaddr_nl *addr = msg->msg_name;
1373 u32 dst_portid;
1374 u32 dst_group;
1375 struct sk_buff *skb;
1376 int err;
1377 struct scm_cookie scm;
1378
1379 if (msg->msg_flags&MSG_OOB)
1380 return -EOPNOTSUPP;
1381
1382 if (NULL == siocb->scm)
1383 siocb->scm = &scm;
1384
1385 err = scm_send(sock, msg, siocb->scm, true);
1386 if (err < 0)
1387 return err;
1388
1389 if (msg->msg_namelen) {
1390 err = -EINVAL;
1391 if (addr->nl_family != AF_NETLINK)
1392 goto out;
1393 dst_portid = addr->nl_pid;
1394 dst_group = ffs(addr->nl_groups);
1395 err = -EPERM;
1396 if ((dst_group || dst_portid) &&
1397 !netlink_capable(sock, NL_CFG_F_NONROOT_SEND))
1398 goto out;
1399 } else {
1400 dst_portid = nlk->dst_portid;
1401 dst_group = nlk->dst_group;
1402 }
1403
1404 if (!nlk->portid) {
1405 err = netlink_autobind(sock);
1406 if (err)
1407 goto out;
1408 }
1409
1410 err = -EMSGSIZE;
1411 if (len > sk->sk_sndbuf - 32)
1412 goto out;
1413 err = -ENOBUFS;
1414 skb = alloc_skb(len, GFP_KERNEL);
1415 if (skb == NULL)
1416 goto out;
1417
1418 NETLINK_CB(skb).portid = nlk->portid;
1419 NETLINK_CB(skb).dst_group = dst_group;
1420 NETLINK_CB(skb).creds = siocb->scm->creds;
1421
1422 err = -EFAULT;
1423 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1424 kfree_skb(skb);
1425 goto out;
1426 }
1427
1428 err = security_netlink_send(sk, skb);
1429 if (err) {
1430 kfree_skb(skb);
1431 goto out;
1432 }
1433
1434 if (dst_group) {
1435 atomic_inc(&skb->users);
1436 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
1437 }
1438 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
1439
1440 out:
1441 scm_destroy(siocb->scm);
1442 return err;
1443 }
1444
1445 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1446 struct msghdr *msg, size_t len,
1447 int flags)
1448 {
1449 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1450 struct scm_cookie scm;
1451 struct sock *sk = sock->sk;
1452 struct netlink_sock *nlk = nlk_sk(sk);
1453 int noblock = flags&MSG_DONTWAIT;
1454 size_t copied;
1455 struct sk_buff *skb, *data_skb;
1456 int err, ret;
1457
1458 if (flags&MSG_OOB)
1459 return -EOPNOTSUPP;
1460
1461 copied = 0;
1462
1463 skb = skb_recv_datagram(sk, flags, noblock, &err);
1464 if (skb == NULL)
1465 goto out;
1466
1467 data_skb = skb;
1468
1469 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1470 if (unlikely(skb_shinfo(skb)->frag_list)) {
1471 /*
1472 * If this skb has a frag_list, then here that means that we
1473 * will have to use the frag_list skb's data for compat tasks
1474 * and the regular skb's data for normal (non-compat) tasks.
1475 *
1476 * If we need to send the compat skb, assign it to the
1477 * 'data_skb' variable so that it will be used below for data
1478 * copying. We keep 'skb' for everything else, including
1479 * freeing both later.
1480 */
1481 if (flags & MSG_CMSG_COMPAT)
1482 data_skb = skb_shinfo(skb)->frag_list;
1483 }
1484 #endif
1485
1486 msg->msg_namelen = 0;
1487
1488 copied = data_skb->len;
1489 if (len < copied) {
1490 msg->msg_flags |= MSG_TRUNC;
1491 copied = len;
1492 }
1493
1494 skb_reset_transport_header(data_skb);
1495 err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
1496
1497 if (msg->msg_name) {
1498 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1499 addr->nl_family = AF_NETLINK;
1500 addr->nl_pad = 0;
1501 addr->nl_pid = NETLINK_CB(skb).portid;
1502 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1503 msg->msg_namelen = sizeof(*addr);
1504 }
1505
1506 if (nlk->flags & NETLINK_RECV_PKTINFO)
1507 netlink_cmsg_recv_pktinfo(msg, skb);
1508
1509 if (NULL == siocb->scm) {
1510 memset(&scm, 0, sizeof(scm));
1511 siocb->scm = &scm;
1512 }
1513 siocb->scm->creds = *NETLINK_CREDS(skb);
1514 if (flags & MSG_TRUNC)
1515 copied = data_skb->len;
1516
1517 skb_free_datagram(sk, skb);
1518
1519 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1520 ret = netlink_dump(sk);
1521 if (ret) {
1522 sk->sk_err = ret;
1523 sk->sk_error_report(sk);
1524 }
1525 }
1526
1527 scm_recv(sock, msg, siocb->scm, flags);
1528 out:
1529 netlink_rcv_wake(sk);
1530 return err ? : copied;
1531 }
1532
1533 static void netlink_data_ready(struct sock *sk, int len)
1534 {
1535 BUG();
1536 }
1537
1538 /*
1539 * We export these functions to other modules. They provide a
1540 * complete set of kernel non-blocking support for message
1541 * queueing.
1542 */
1543
1544 struct sock *
1545 __netlink_kernel_create(struct net *net, int unit, struct module *module,
1546 struct netlink_kernel_cfg *cfg)
1547 {
1548 struct socket *sock;
1549 struct sock *sk;
1550 struct netlink_sock *nlk;
1551 struct listeners *listeners = NULL;
1552 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
1553 unsigned int groups;
1554
1555 BUG_ON(!nl_table);
1556
1557 if (unit < 0 || unit >= MAX_LINKS)
1558 return NULL;
1559
1560 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1561 return NULL;
1562
1563 /*
1564 * We have to just have a reference on the net from sk, but don't
1565 * get_net it. Besides, we cannot get and then put the net here.
1566 * So we create one inside init_net and the move it to net.
1567 */
1568
1569 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1570 goto out_sock_release_nosk;
1571
1572 sk = sock->sk;
1573 sk_change_net(sk, net);
1574
1575 if (!cfg || cfg->groups < 32)
1576 groups = 32;
1577 else
1578 groups = cfg->groups;
1579
1580 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
1581 if (!listeners)
1582 goto out_sock_release;
1583
1584 sk->sk_data_ready = netlink_data_ready;
1585 if (cfg && cfg->input)
1586 nlk_sk(sk)->netlink_rcv = cfg->input;
1587
1588 if (netlink_insert(sk, net, 0))
1589 goto out_sock_release;
1590
1591 nlk = nlk_sk(sk);
1592 nlk->flags |= NETLINK_KERNEL_SOCKET;
1593
1594 netlink_table_grab();
1595 if (!nl_table[unit].registered) {
1596 nl_table[unit].groups = groups;
1597 rcu_assign_pointer(nl_table[unit].listeners, listeners);
1598 nl_table[unit].cb_mutex = cb_mutex;
1599 nl_table[unit].module = module;
1600 if (cfg) {
1601 nl_table[unit].bind = cfg->bind;
1602 nl_table[unit].flags = cfg->flags;
1603 }
1604 nl_table[unit].registered = 1;
1605 } else {
1606 kfree(listeners);
1607 nl_table[unit].registered++;
1608 }
1609 netlink_table_ungrab();
1610 return sk;
1611
1612 out_sock_release:
1613 kfree(listeners);
1614 netlink_kernel_release(sk);
1615 return NULL;
1616
1617 out_sock_release_nosk:
1618 sock_release(sock);
1619 return NULL;
1620 }
1621 EXPORT_SYMBOL(__netlink_kernel_create);
1622
1623 void
1624 netlink_kernel_release(struct sock *sk)
1625 {
1626 sk_release_kernel(sk);
1627 }
1628 EXPORT_SYMBOL(netlink_kernel_release);
1629
1630 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1631 {
1632 struct listeners *new, *old;
1633 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1634
1635 if (groups < 32)
1636 groups = 32;
1637
1638 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1639 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
1640 if (!new)
1641 return -ENOMEM;
1642 old = nl_deref_protected(tbl->listeners);
1643 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
1644 rcu_assign_pointer(tbl->listeners, new);
1645
1646 kfree_rcu(old, rcu);
1647 }
1648 tbl->groups = groups;
1649
1650 return 0;
1651 }
1652
1653 /**
1654 * netlink_change_ngroups - change number of multicast groups
1655 *
1656 * This changes the number of multicast groups that are available
1657 * on a certain netlink family. Note that it is not possible to
1658 * change the number of groups to below 32. Also note that it does
1659 * not implicitly call netlink_clear_multicast_users() when the
1660 * number of groups is reduced.
1661 *
1662 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1663 * @groups: The new number of groups.
1664 */
1665 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1666 {
1667 int err;
1668
1669 netlink_table_grab();
1670 err = __netlink_change_ngroups(sk, groups);
1671 netlink_table_ungrab();
1672
1673 return err;
1674 }
1675
1676 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1677 {
1678 struct sock *sk;
1679 struct hlist_node *node;
1680 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1681
1682 sk_for_each_bound(sk, node, &tbl->mc_list)
1683 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1684 }
1685
1686 /**
1687 * netlink_clear_multicast_users - kick off multicast listeners
1688 *
1689 * This function removes all listeners from the given group.
1690 * @ksk: The kernel netlink socket, as returned by
1691 * netlink_kernel_create().
1692 * @group: The multicast group to clear.
1693 */
1694 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1695 {
1696 netlink_table_grab();
1697 __netlink_clear_multicast_users(ksk, group);
1698 netlink_table_ungrab();
1699 }
1700
1701 struct nlmsghdr *
1702 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
1703 {
1704 struct nlmsghdr *nlh;
1705 int size = NLMSG_LENGTH(len);
1706
1707 nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
1708 nlh->nlmsg_type = type;
1709 nlh->nlmsg_len = size;
1710 nlh->nlmsg_flags = flags;
1711 nlh->nlmsg_pid = portid;
1712 nlh->nlmsg_seq = seq;
1713 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
1714 memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size);
1715 return nlh;
1716 }
1717 EXPORT_SYMBOL(__nlmsg_put);
1718
1719 /*
1720 * It looks a bit ugly.
1721 * It would be better to create kernel thread.
1722 */
1723
1724 static int netlink_dump(struct sock *sk)
1725 {
1726 struct netlink_sock *nlk = nlk_sk(sk);
1727 struct netlink_callback *cb;
1728 struct sk_buff *skb = NULL;
1729 struct nlmsghdr *nlh;
1730 int len, err = -ENOBUFS;
1731 int alloc_size;
1732
1733 mutex_lock(nlk->cb_mutex);
1734
1735 cb = nlk->cb;
1736 if (cb == NULL) {
1737 err = -EINVAL;
1738 goto errout_skb;
1739 }
1740
1741 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
1742
1743 skb = sock_rmalloc(sk, alloc_size, 0, GFP_KERNEL);
1744 if (!skb)
1745 goto errout_skb;
1746
1747 len = cb->dump(skb, cb);
1748
1749 if (len > 0) {
1750 mutex_unlock(nlk->cb_mutex);
1751
1752 if (sk_filter(sk, skb))
1753 kfree_skb(skb);
1754 else
1755 __netlink_sendskb(sk, skb);
1756 return 0;
1757 }
1758
1759 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1760 if (!nlh)
1761 goto errout_skb;
1762
1763 nl_dump_check_consistent(cb, nlh);
1764
1765 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1766
1767 if (sk_filter(sk, skb))
1768 kfree_skb(skb);
1769 else
1770 __netlink_sendskb(sk, skb);
1771
1772 if (cb->done)
1773 cb->done(cb);
1774 nlk->cb = NULL;
1775 mutex_unlock(nlk->cb_mutex);
1776
1777 module_put(cb->module);
1778 netlink_consume_callback(cb);
1779 return 0;
1780
1781 errout_skb:
1782 mutex_unlock(nlk->cb_mutex);
1783 kfree_skb(skb);
1784 return err;
1785 }
1786
1787 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1788 const struct nlmsghdr *nlh,
1789 struct netlink_dump_control *control)
1790 {
1791 struct netlink_callback *cb;
1792 struct sock *sk;
1793 struct netlink_sock *nlk;
1794 int ret;
1795
1796 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1797 if (cb == NULL)
1798 return -ENOBUFS;
1799
1800 cb->dump = control->dump;
1801 cb->done = control->done;
1802 cb->nlh = nlh;
1803 cb->data = control->data;
1804 cb->module = control->module;
1805 cb->min_dump_alloc = control->min_dump_alloc;
1806 atomic_inc(&skb->users);
1807 cb->skb = skb;
1808
1809 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
1810 if (sk == NULL) {
1811 netlink_destroy_callback(cb);
1812 return -ECONNREFUSED;
1813 }
1814 nlk = nlk_sk(sk);
1815
1816 mutex_lock(nlk->cb_mutex);
1817 /* A dump is in progress... */
1818 if (nlk->cb) {
1819 mutex_unlock(nlk->cb_mutex);
1820 netlink_destroy_callback(cb);
1821 ret = -EBUSY;
1822 goto out;
1823 }
1824 /* add reference of module which cb->dump belongs to */
1825 if (!try_module_get(cb->module)) {
1826 mutex_unlock(nlk->cb_mutex);
1827 netlink_destroy_callback(cb);
1828 ret = -EPROTONOSUPPORT;
1829 goto out;
1830 }
1831
1832 nlk->cb = cb;
1833 mutex_unlock(nlk->cb_mutex);
1834
1835 ret = netlink_dump(sk);
1836 out:
1837 sock_put(sk);
1838
1839 if (ret)
1840 return ret;
1841
1842 /* We successfully started a dump, by returning -EINTR we
1843 * signal not to send ACK even if it was requested.
1844 */
1845 return -EINTR;
1846 }
1847 EXPORT_SYMBOL(__netlink_dump_start);
1848
1849 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1850 {
1851 struct sk_buff *skb;
1852 struct nlmsghdr *rep;
1853 struct nlmsgerr *errmsg;
1854 size_t payload = sizeof(*errmsg);
1855
1856 /* error messages get the original request appened */
1857 if (err)
1858 payload += nlmsg_len(nlh);
1859
1860 skb = nlmsg_new(payload, GFP_KERNEL);
1861 if (!skb) {
1862 struct sock *sk;
1863
1864 sk = netlink_lookup(sock_net(in_skb->sk),
1865 in_skb->sk->sk_protocol,
1866 NETLINK_CB(in_skb).portid);
1867 if (sk) {
1868 sk->sk_err = ENOBUFS;
1869 sk->sk_error_report(sk);
1870 sock_put(sk);
1871 }
1872 return;
1873 }
1874
1875 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
1876 NLMSG_ERROR, payload, 0);
1877 errmsg = nlmsg_data(rep);
1878 errmsg->error = err;
1879 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1880 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
1881 }
1882 EXPORT_SYMBOL(netlink_ack);
1883
1884 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1885 struct nlmsghdr *))
1886 {
1887 struct nlmsghdr *nlh;
1888 int err;
1889
1890 while (skb->len >= nlmsg_total_size(0)) {
1891 int msglen;
1892
1893 nlh = nlmsg_hdr(skb);
1894 err = 0;
1895
1896 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1897 return 0;
1898
1899 /* Only requests are handled by the kernel */
1900 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1901 goto ack;
1902
1903 /* Skip control messages */
1904 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1905 goto ack;
1906
1907 err = cb(skb, nlh);
1908 if (err == -EINTR)
1909 goto skip;
1910
1911 ack:
1912 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1913 netlink_ack(skb, nlh, err);
1914
1915 skip:
1916 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1917 if (msglen > skb->len)
1918 msglen = skb->len;
1919 skb_pull(skb, msglen);
1920 }
1921
1922 return 0;
1923 }
1924 EXPORT_SYMBOL(netlink_rcv_skb);
1925
1926 /**
1927 * nlmsg_notify - send a notification netlink message
1928 * @sk: netlink socket to use
1929 * @skb: notification message
1930 * @portid: destination netlink portid for reports or 0
1931 * @group: destination multicast group or 0
1932 * @report: 1 to report back, 0 to disable
1933 * @flags: allocation flags
1934 */
1935 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
1936 unsigned int group, int report, gfp_t flags)
1937 {
1938 int err = 0;
1939
1940 if (group) {
1941 int exclude_portid = 0;
1942
1943 if (report) {
1944 atomic_inc(&skb->users);
1945 exclude_portid = portid;
1946 }
1947
1948 /* errors reported via destination sk->sk_err, but propagate
1949 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1950 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
1951 }
1952
1953 if (report) {
1954 int err2;
1955
1956 err2 = nlmsg_unicast(sk, skb, portid);
1957 if (!err || err == -ESRCH)
1958 err = err2;
1959 }
1960
1961 return err;
1962 }
1963 EXPORT_SYMBOL(nlmsg_notify);
1964
1965 #ifdef CONFIG_PROC_FS
1966 struct nl_seq_iter {
1967 struct seq_net_private p;
1968 int link;
1969 int hash_idx;
1970 };
1971
1972 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1973 {
1974 struct nl_seq_iter *iter = seq->private;
1975 int i, j;
1976 struct sock *s;
1977 struct hlist_node *node;
1978 loff_t off = 0;
1979
1980 for (i = 0; i < MAX_LINKS; i++) {
1981 struct nl_portid_hash *hash = &nl_table[i].hash;
1982
1983 for (j = 0; j <= hash->mask; j++) {
1984 sk_for_each(s, node, &hash->table[j]) {
1985 if (sock_net(s) != seq_file_net(seq))
1986 continue;
1987 if (off == pos) {
1988 iter->link = i;
1989 iter->hash_idx = j;
1990 return s;
1991 }
1992 ++off;
1993 }
1994 }
1995 }
1996 return NULL;
1997 }
1998
1999 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
2000 __acquires(nl_table_lock)
2001 {
2002 read_lock(&nl_table_lock);
2003 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2004 }
2005
2006 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2007 {
2008 struct sock *s;
2009 struct nl_seq_iter *iter;
2010 int i, j;
2011
2012 ++*pos;
2013
2014 if (v == SEQ_START_TOKEN)
2015 return netlink_seq_socket_idx(seq, 0);
2016
2017 iter = seq->private;
2018 s = v;
2019 do {
2020 s = sk_next(s);
2021 } while (s && sock_net(s) != seq_file_net(seq));
2022 if (s)
2023 return s;
2024
2025 i = iter->link;
2026 j = iter->hash_idx + 1;
2027
2028 do {
2029 struct nl_portid_hash *hash = &nl_table[i].hash;
2030
2031 for (; j <= hash->mask; j++) {
2032 s = sk_head(&hash->table[j]);
2033 while (s && sock_net(s) != seq_file_net(seq))
2034 s = sk_next(s);
2035 if (s) {
2036 iter->link = i;
2037 iter->hash_idx = j;
2038 return s;
2039 }
2040 }
2041
2042 j = 0;
2043 } while (++i < MAX_LINKS);
2044
2045 return NULL;
2046 }
2047
2048 static void netlink_seq_stop(struct seq_file *seq, void *v)
2049 __releases(nl_table_lock)
2050 {
2051 read_unlock(&nl_table_lock);
2052 }
2053
2054
2055 static int netlink_seq_show(struct seq_file *seq, void *v)
2056 {
2057 if (v == SEQ_START_TOKEN) {
2058 seq_puts(seq,
2059 "sk Eth Pid Groups "
2060 "Rmem Wmem Dump Locks Drops Inode\n");
2061 } else {
2062 struct sock *s = v;
2063 struct netlink_sock *nlk = nlk_sk(s);
2064
2065 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %pK %-8d %-8d %-8lu\n",
2066 s,
2067 s->sk_protocol,
2068 nlk->portid,
2069 nlk->groups ? (u32)nlk->groups[0] : 0,
2070 sk_rmem_alloc_get(s),
2071 sk_wmem_alloc_get(s),
2072 nlk->cb,
2073 atomic_read(&s->sk_refcnt),
2074 atomic_read(&s->sk_drops),
2075 sock_i_ino(s)
2076 );
2077
2078 }
2079 return 0;
2080 }
2081
2082 static const struct seq_operations netlink_seq_ops = {
2083 .start = netlink_seq_start,
2084 .next = netlink_seq_next,
2085 .stop = netlink_seq_stop,
2086 .show = netlink_seq_show,
2087 };
2088
2089
2090 static int netlink_seq_open(struct inode *inode, struct file *file)
2091 {
2092 return seq_open_net(inode, file, &netlink_seq_ops,
2093 sizeof(struct nl_seq_iter));
2094 }
2095
2096 static const struct file_operations netlink_seq_fops = {
2097 .owner = THIS_MODULE,
2098 .open = netlink_seq_open,
2099 .read = seq_read,
2100 .llseek = seq_lseek,
2101 .release = seq_release_net,
2102 };
2103
2104 #endif
2105
2106 int netlink_register_notifier(struct notifier_block *nb)
2107 {
2108 return atomic_notifier_chain_register(&netlink_chain, nb);
2109 }
2110 EXPORT_SYMBOL(netlink_register_notifier);
2111
2112 int netlink_unregister_notifier(struct notifier_block *nb)
2113 {
2114 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2115 }
2116 EXPORT_SYMBOL(netlink_unregister_notifier);
2117
2118 static const struct proto_ops netlink_ops = {
2119 .family = PF_NETLINK,
2120 .owner = THIS_MODULE,
2121 .release = netlink_release,
2122 .bind = netlink_bind,
2123 .connect = netlink_connect,
2124 .socketpair = sock_no_socketpair,
2125 .accept = sock_no_accept,
2126 .getname = netlink_getname,
2127 .poll = datagram_poll,
2128 .ioctl = sock_no_ioctl,
2129 .listen = sock_no_listen,
2130 .shutdown = sock_no_shutdown,
2131 .setsockopt = netlink_setsockopt,
2132 .getsockopt = netlink_getsockopt,
2133 .sendmsg = netlink_sendmsg,
2134 .recvmsg = netlink_recvmsg,
2135 .mmap = sock_no_mmap,
2136 .sendpage = sock_no_sendpage,
2137 };
2138
2139 static const struct net_proto_family netlink_family_ops = {
2140 .family = PF_NETLINK,
2141 .create = netlink_create,
2142 .owner = THIS_MODULE, /* for consistency 8) */
2143 };
2144
2145 static int __net_init netlink_net_init(struct net *net)
2146 {
2147 #ifdef CONFIG_PROC_FS
2148 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2149 return -ENOMEM;
2150 #endif
2151 return 0;
2152 }
2153
2154 static void __net_exit netlink_net_exit(struct net *net)
2155 {
2156 #ifdef CONFIG_PROC_FS
2157 proc_net_remove(net, "netlink");
2158 #endif
2159 }
2160
2161 static void __init netlink_add_usersock_entry(void)
2162 {
2163 struct listeners *listeners;
2164 int groups = 32;
2165
2166 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2167 if (!listeners)
2168 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2169
2170 netlink_table_grab();
2171
2172 nl_table[NETLINK_USERSOCK].groups = groups;
2173 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2174 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2175 nl_table[NETLINK_USERSOCK].registered = 1;
2176 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
2177
2178 netlink_table_ungrab();
2179 }
2180
2181 static struct pernet_operations __net_initdata netlink_net_ops = {
2182 .init = netlink_net_init,
2183 .exit = netlink_net_exit,
2184 };
2185
2186 static int __init netlink_proto_init(void)
2187 {
2188 struct sk_buff *dummy_skb;
2189 int i;
2190 unsigned long limit;
2191 unsigned int order;
2192 int err = proto_register(&netlink_proto, 0);
2193
2194 if (err != 0)
2195 goto out;
2196
2197 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2198
2199 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2200 if (!nl_table)
2201 goto panic;
2202
2203 if (totalram_pages >= (128 * 1024))
2204 limit = totalram_pages >> (21 - PAGE_SHIFT);
2205 else
2206 limit = totalram_pages >> (23 - PAGE_SHIFT);
2207
2208 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2209 limit = (1UL << order) / sizeof(struct hlist_head);
2210 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2211
2212 for (i = 0; i < MAX_LINKS; i++) {
2213 struct nl_portid_hash *hash = &nl_table[i].hash;
2214
2215 hash->table = nl_portid_hash_zalloc(1 * sizeof(*hash->table));
2216 if (!hash->table) {
2217 while (i-- > 0)
2218 nl_portid_hash_free(nl_table[i].hash.table,
2219 1 * sizeof(*hash->table));
2220 kfree(nl_table);
2221 goto panic;
2222 }
2223 hash->max_shift = order;
2224 hash->shift = 0;
2225 hash->mask = 0;
2226 hash->rehash_time = jiffies;
2227 }
2228
2229 netlink_add_usersock_entry();
2230
2231 sock_register(&netlink_family_ops);
2232 register_pernet_subsys(&netlink_net_ops);
2233 /* The netlink device handler may be needed early. */
2234 rtnetlink_init();
2235 out:
2236 return err;
2237 panic:
2238 panic("netlink_init: Cannot allocate nl_table\n");
2239 }
2240
2241 core_initcall(netlink_proto_init);