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platform: x86: asus_acpi: world-writable procfs files
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / netlink / af_netlink.c
blob0052d3c3fe00324839be953faaf1c9c0fbd7fb79
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 pid;
71 u32 dst_pid;
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 struct module *module;
84 };
85
86 struct listeners_rcu_head {
87 struct rcu_head rcu_head;
88 void *ptr;
89 };
90
91 #define NETLINK_KERNEL_SOCKET 0x1
92 #define NETLINK_RECV_PKTINFO 0x2
93 #define NETLINK_BROADCAST_SEND_ERROR 0x4
94 #define NETLINK_RECV_NO_ENOBUFS 0x8
95
96 static inline struct netlink_sock *nlk_sk(struct sock *sk)
97 {
98 return container_of(sk, struct netlink_sock, sk);
99 }
100
101 static inline int netlink_is_kernel(struct sock *sk)
102 {
103 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
104 }
105
106 struct nl_pid_hash {
107 struct hlist_head *table;
108 unsigned long rehash_time;
109
110 unsigned int mask;
111 unsigned int shift;
112
113 unsigned int entries;
114 unsigned int max_shift;
115
116 u32 rnd;
117 };
118
119 struct netlink_table {
120 struct nl_pid_hash hash;
121 struct hlist_head mc_list;
122 unsigned long *listeners;
123 unsigned int nl_nonroot;
124 unsigned int groups;
125 struct mutex *cb_mutex;
126 struct module *module;
127 int registered;
128 };
129
130 static struct netlink_table *nl_table;
131
132 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
133
134 static int netlink_dump(struct sock *sk);
135 static void netlink_destroy_callback(struct netlink_callback *cb);
136
137 static DEFINE_RWLOCK(nl_table_lock);
138 static atomic_t nl_table_users = ATOMIC_INIT(0);
139
140 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
141
142 static u32 netlink_group_mask(u32 group)
143 {
144 return group ? 1 << (group - 1) : 0;
145 }
146
147 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
148 {
149 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
150 }
151
152 static void netlink_sock_destruct(struct sock *sk)
153 {
154 struct netlink_sock *nlk = nlk_sk(sk);
155
156 if (nlk->cb) {
157 if (nlk->cb->done)
158 nlk->cb->done(nlk->cb);
159 netlink_destroy_callback(nlk->cb);
160 }
161
162 skb_queue_purge(&sk->sk_receive_queue);
163
164 if (!sock_flag(sk, SOCK_DEAD)) {
165 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
166 return;
167 }
168
169 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
170 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
171 WARN_ON(nlk_sk(sk)->groups);
172 }
173
174 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
175 * SMP. Look, when several writers sleep and reader wakes them up, all but one
176 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
177 * this, _but_ remember, it adds useless work on UP machines.
178 */
179
180 void netlink_table_grab(void)
181 __acquires(nl_table_lock)
182 {
183 might_sleep();
184
185 write_lock_irq(&nl_table_lock);
186
187 if (atomic_read(&nl_table_users)) {
188 DECLARE_WAITQUEUE(wait, current);
189
190 add_wait_queue_exclusive(&nl_table_wait, &wait);
191 for (;;) {
192 set_current_state(TASK_UNINTERRUPTIBLE);
193 if (atomic_read(&nl_table_users) == 0)
194 break;
195 write_unlock_irq(&nl_table_lock);
196 schedule();
197 write_lock_irq(&nl_table_lock);
198 }
199
200 __set_current_state(TASK_RUNNING);
201 remove_wait_queue(&nl_table_wait, &wait);
202 }
203 }
204
205 void netlink_table_ungrab(void)
206 __releases(nl_table_lock)
207 {
208 write_unlock_irq(&nl_table_lock);
209 wake_up(&nl_table_wait);
210 }
211
212 static inline void
213 netlink_lock_table(void)
214 {
215 /* read_lock() synchronizes us to netlink_table_grab */
216
217 read_lock(&nl_table_lock);
218 atomic_inc(&nl_table_users);
219 read_unlock(&nl_table_lock);
220 }
221
222 static inline void
223 netlink_unlock_table(void)
224 {
225 if (atomic_dec_and_test(&nl_table_users))
226 wake_up(&nl_table_wait);
227 }
228
229 static inline struct sock *netlink_lookup(struct net *net, int protocol,
230 u32 pid)
231 {
232 struct nl_pid_hash *hash = &nl_table[protocol].hash;
233 struct hlist_head *head;
234 struct sock *sk;
235 struct hlist_node *node;
236
237 read_lock(&nl_table_lock);
238 head = nl_pid_hashfn(hash, pid);
239 sk_for_each(sk, node, head) {
240 if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) {
241 sock_hold(sk);
242 goto found;
243 }
244 }
245 sk = NULL;
246 found:
247 read_unlock(&nl_table_lock);
248 return sk;
249 }
250
251 static inline struct hlist_head *nl_pid_hash_zalloc(size_t size)
252 {
253 if (size <= PAGE_SIZE)
254 return kzalloc(size, GFP_ATOMIC);
255 else
256 return (struct hlist_head *)
257 __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
258 get_order(size));
259 }
260
261 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
262 {
263 if (size <= PAGE_SIZE)
264 kfree(table);
265 else
266 free_pages((unsigned long)table, get_order(size));
267 }
268
269 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
270 {
271 unsigned int omask, mask, shift;
272 size_t osize, size;
273 struct hlist_head *otable, *table;
274 int i;
275
276 omask = mask = hash->mask;
277 osize = size = (mask + 1) * sizeof(*table);
278 shift = hash->shift;
279
280 if (grow) {
281 if (++shift > hash->max_shift)
282 return 0;
283 mask = mask * 2 + 1;
284 size *= 2;
285 }
286
287 table = nl_pid_hash_zalloc(size);
288 if (!table)
289 return 0;
290
291 otable = hash->table;
292 hash->table = table;
293 hash->mask = mask;
294 hash->shift = shift;
295 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
296
297 for (i = 0; i <= omask; i++) {
298 struct sock *sk;
299 struct hlist_node *node, *tmp;
300
301 sk_for_each_safe(sk, node, tmp, &otable[i])
302 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
303 }
304
305 nl_pid_hash_free(otable, osize);
306 hash->rehash_time = jiffies + 10 * 60 * HZ;
307 return 1;
308 }
309
310 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
311 {
312 int avg = hash->entries >> hash->shift;
313
314 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
315 return 1;
316
317 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
318 nl_pid_hash_rehash(hash, 0);
319 return 1;
320 }
321
322 return 0;
323 }
324
325 static const struct proto_ops netlink_ops;
326
327 static void
328 netlink_update_listeners(struct sock *sk)
329 {
330 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
331 struct hlist_node *node;
332 unsigned long mask;
333 unsigned int i;
334
335 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
336 mask = 0;
337 sk_for_each_bound(sk, node, &tbl->mc_list) {
338 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
339 mask |= nlk_sk(sk)->groups[i];
340 }
341 tbl->listeners[i] = mask;
342 }
343 /* this function is only called with the netlink table "grabbed", which
344 * makes sure updates are visible before bind or setsockopt return. */
345 }
346
347 static int netlink_insert(struct sock *sk, struct net *net, u32 pid)
348 {
349 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
350 struct hlist_head *head;
351 int err = -EADDRINUSE;
352 struct sock *osk;
353 struct hlist_node *node;
354 int len;
355
356 netlink_table_grab();
357 head = nl_pid_hashfn(hash, pid);
358 len = 0;
359 sk_for_each(osk, node, head) {
360 if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->pid == pid))
361 break;
362 len++;
363 }
364 if (node)
365 goto err;
366
367 err = -EBUSY;
368 if (nlk_sk(sk)->pid)
369 goto err;
370
371 err = -ENOMEM;
372 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
373 goto err;
374
375 if (len && nl_pid_hash_dilute(hash, len))
376 head = nl_pid_hashfn(hash, pid);
377 hash->entries++;
378 nlk_sk(sk)->pid = pid;
379 sk_add_node(sk, head);
380 err = 0;
381
382 err:
383 netlink_table_ungrab();
384 return err;
385 }
386
387 static void netlink_remove(struct sock *sk)
388 {
389 netlink_table_grab();
390 if (sk_del_node_init(sk))
391 nl_table[sk->sk_protocol].hash.entries--;
392 if (nlk_sk(sk)->subscriptions)
393 __sk_del_bind_node(sk);
394 netlink_table_ungrab();
395 }
396
397 static struct proto netlink_proto = {
398 .name = "NETLINK",
399 .owner = THIS_MODULE,
400 .obj_size = sizeof(struct netlink_sock),
401 };
402
403 static int __netlink_create(struct net *net, struct socket *sock,
404 struct mutex *cb_mutex, int protocol)
405 {
406 struct sock *sk;
407 struct netlink_sock *nlk;
408
409 sock->ops = &netlink_ops;
410
411 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
412 if (!sk)
413 return -ENOMEM;
414
415 sock_init_data(sock, sk);
416
417 nlk = nlk_sk(sk);
418 if (cb_mutex)
419 nlk->cb_mutex = cb_mutex;
420 else {
421 nlk->cb_mutex = &nlk->cb_def_mutex;
422 mutex_init(nlk->cb_mutex);
423 }
424 init_waitqueue_head(&nlk->wait);
425
426 sk->sk_destruct = netlink_sock_destruct;
427 sk->sk_protocol = protocol;
428 return 0;
429 }
430
431 static int netlink_create(struct net *net, struct socket *sock, int protocol,
432 int kern)
433 {
434 struct module *module = NULL;
435 struct mutex *cb_mutex;
436 struct netlink_sock *nlk;
437 int err = 0;
438
439 sock->state = SS_UNCONNECTED;
440
441 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
442 return -ESOCKTNOSUPPORT;
443
444 if (protocol < 0 || protocol >= MAX_LINKS)
445 return -EPROTONOSUPPORT;
446
447 netlink_lock_table();
448 #ifdef CONFIG_MODULES
449 if (!nl_table[protocol].registered) {
450 netlink_unlock_table();
451 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
452 netlink_lock_table();
453 }
454 #endif
455 if (nl_table[protocol].registered &&
456 try_module_get(nl_table[protocol].module))
457 module = nl_table[protocol].module;
458 else
459 err = -EPROTONOSUPPORT;
460 cb_mutex = nl_table[protocol].cb_mutex;
461 netlink_unlock_table();
462
463 if (err < 0)
464 goto out;
465
466 err = __netlink_create(net, sock, cb_mutex, protocol);
467 if (err < 0)
468 goto out_module;
469
470 local_bh_disable();
471 sock_prot_inuse_add(net, &netlink_proto, 1);
472 local_bh_enable();
473
474 nlk = nlk_sk(sock->sk);
475 nlk->module = module;
476 out:
477 return err;
478
479 out_module:
480 module_put(module);
481 goto out;
482 }
483
484 static int netlink_release(struct socket *sock)
485 {
486 struct sock *sk = sock->sk;
487 struct netlink_sock *nlk;
488
489 if (!sk)
490 return 0;
491
492 netlink_remove(sk);
493 sock_orphan(sk);
494 nlk = nlk_sk(sk);
495
496 /*
497 * OK. Socket is unlinked, any packets that arrive now
498 * will be purged.
499 */
500
501 sock->sk = NULL;
502 wake_up_interruptible_all(&nlk->wait);
503
504 skb_queue_purge(&sk->sk_write_queue);
505
506 if (nlk->pid) {
507 struct netlink_notify n = {
508 .net = sock_net(sk),
509 .protocol = sk->sk_protocol,
510 .pid = nlk->pid,
511 };
512 atomic_notifier_call_chain(&netlink_chain,
513 NETLINK_URELEASE, &n);
514 }
515
516 module_put(nlk->module);
517
518 netlink_table_grab();
519 if (netlink_is_kernel(sk)) {
520 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
521 if (--nl_table[sk->sk_protocol].registered == 0) {
522 kfree(nl_table[sk->sk_protocol].listeners);
523 nl_table[sk->sk_protocol].module = NULL;
524 nl_table[sk->sk_protocol].registered = 0;
525 }
526 } else if (nlk->subscriptions)
527 netlink_update_listeners(sk);
528 netlink_table_ungrab();
529
530 kfree(nlk->groups);
531 nlk->groups = NULL;
532
533 local_bh_disable();
534 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
535 local_bh_enable();
536 sock_put(sk);
537 return 0;
538 }
539
540 static int netlink_autobind(struct socket *sock)
541 {
542 struct sock *sk = sock->sk;
543 struct net *net = sock_net(sk);
544 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
545 struct hlist_head *head;
546 struct sock *osk;
547 struct hlist_node *node;
548 s32 pid = current->tgid;
549 int err;
550 static s32 rover = -4097;
551
552 retry:
553 cond_resched();
554 netlink_table_grab();
555 head = nl_pid_hashfn(hash, pid);
556 sk_for_each(osk, node, head) {
557 if (!net_eq(sock_net(osk), net))
558 continue;
559 if (nlk_sk(osk)->pid == pid) {
560 /* Bind collision, search negative pid values. */
561 pid = rover--;
562 if (rover > -4097)
563 rover = -4097;
564 netlink_table_ungrab();
565 goto retry;
566 }
567 }
568 netlink_table_ungrab();
569
570 err = netlink_insert(sk, net, pid);
571 if (err == -EADDRINUSE)
572 goto retry;
573
574 /* If 2 threads race to autobind, that is fine. */
575 if (err == -EBUSY)
576 err = 0;
577
578 return err;
579 }
580
581 static inline int netlink_capable(struct socket *sock, unsigned int flag)
582 {
583 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
584 capable(CAP_NET_ADMIN);
585 }
586
587 static void
588 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
589 {
590 struct netlink_sock *nlk = nlk_sk(sk);
591
592 if (nlk->subscriptions && !subscriptions)
593 __sk_del_bind_node(sk);
594 else if (!nlk->subscriptions && subscriptions)
595 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
596 nlk->subscriptions = subscriptions;
597 }
598
599 static int netlink_realloc_groups(struct sock *sk)
600 {
601 struct netlink_sock *nlk = nlk_sk(sk);
602 unsigned int groups;
603 unsigned long *new_groups;
604 int err = 0;
605
606 netlink_table_grab();
607
608 groups = nl_table[sk->sk_protocol].groups;
609 if (!nl_table[sk->sk_protocol].registered) {
610 err = -ENOENT;
611 goto out_unlock;
612 }
613
614 if (nlk->ngroups >= groups)
615 goto out_unlock;
616
617 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
618 if (new_groups == NULL) {
619 err = -ENOMEM;
620 goto out_unlock;
621 }
622 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
623 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
624
625 nlk->groups = new_groups;
626 nlk->ngroups = groups;
627 out_unlock:
628 netlink_table_ungrab();
629 return err;
630 }
631
632 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
633 int addr_len)
634 {
635 struct sock *sk = sock->sk;
636 struct net *net = sock_net(sk);
637 struct netlink_sock *nlk = nlk_sk(sk);
638 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
639 int err;
640
641 if (nladdr->nl_family != AF_NETLINK)
642 return -EINVAL;
643
644 /* Only superuser is allowed to listen multicasts */
645 if (nladdr->nl_groups) {
646 if (!netlink_capable(sock, NL_NONROOT_RECV))
647 return -EPERM;
648 err = netlink_realloc_groups(sk);
649 if (err)
650 return err;
651 }
652
653 if (nlk->pid) {
654 if (nladdr->nl_pid != nlk->pid)
655 return -EINVAL;
656 } else {
657 err = nladdr->nl_pid ?
658 netlink_insert(sk, net, nladdr->nl_pid) :
659 netlink_autobind(sock);
660 if (err)
661 return err;
662 }
663
664 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
665 return 0;
666
667 netlink_table_grab();
668 netlink_update_subscriptions(sk, nlk->subscriptions +
669 hweight32(nladdr->nl_groups) -
670 hweight32(nlk->groups[0]));
671 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
672 netlink_update_listeners(sk);
673 netlink_table_ungrab();
674
675 return 0;
676 }
677
678 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
679 int alen, int flags)
680 {
681 int err = 0;
682 struct sock *sk = sock->sk;
683 struct netlink_sock *nlk = nlk_sk(sk);
684 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
685
686 if (addr->sa_family == AF_UNSPEC) {
687 sk->sk_state = NETLINK_UNCONNECTED;
688 nlk->dst_pid = 0;
689 nlk->dst_group = 0;
690 return 0;
691 }
692 if (addr->sa_family != AF_NETLINK)
693 return -EINVAL;
694
695 /* Only superuser is allowed to send multicasts */
696 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
697 return -EPERM;
698
699 if (!nlk->pid)
700 err = netlink_autobind(sock);
701
702 if (err == 0) {
703 sk->sk_state = NETLINK_CONNECTED;
704 nlk->dst_pid = nladdr->nl_pid;
705 nlk->dst_group = ffs(nladdr->nl_groups);
706 }
707
708 return err;
709 }
710
711 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
712 int *addr_len, int peer)
713 {
714 struct sock *sk = sock->sk;
715 struct netlink_sock *nlk = nlk_sk(sk);
716 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
717
718 nladdr->nl_family = AF_NETLINK;
719 nladdr->nl_pad = 0;
720 *addr_len = sizeof(*nladdr);
721
722 if (peer) {
723 nladdr->nl_pid = nlk->dst_pid;
724 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
725 } else {
726 nladdr->nl_pid = nlk->pid;
727 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
728 }
729 return 0;
730 }
731
732 static void netlink_overrun(struct sock *sk)
733 {
734 struct netlink_sock *nlk = nlk_sk(sk);
735
736 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
737 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
738 sk->sk_err = ENOBUFS;
739 sk->sk_error_report(sk);
740 }
741 }
742 atomic_inc(&sk->sk_drops);
743 }
744
745 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
746 {
747 struct sock *sock;
748 struct netlink_sock *nlk;
749
750 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid);
751 if (!sock)
752 return ERR_PTR(-ECONNREFUSED);
753
754 /* Don't bother queuing skb if kernel socket has no input function */
755 nlk = nlk_sk(sock);
756 if (sock->sk_state == NETLINK_CONNECTED &&
757 nlk->dst_pid != nlk_sk(ssk)->pid) {
758 sock_put(sock);
759 return ERR_PTR(-ECONNREFUSED);
760 }
761 return sock;
762 }
763
764 struct sock *netlink_getsockbyfilp(struct file *filp)
765 {
766 struct inode *inode = filp->f_path.dentry->d_inode;
767 struct sock *sock;
768
769 if (!S_ISSOCK(inode->i_mode))
770 return ERR_PTR(-ENOTSOCK);
771
772 sock = SOCKET_I(inode)->sk;
773 if (sock->sk_family != AF_NETLINK)
774 return ERR_PTR(-EINVAL);
775
776 sock_hold(sock);
777 return sock;
778 }
779
780 /*
781 * Attach a skb to a netlink socket.
782 * The caller must hold a reference to the destination socket. On error, the
783 * reference is dropped. The skb is not send to the destination, just all
784 * all error checks are performed and memory in the queue is reserved.
785 * Return values:
786 * < 0: error. skb freed, reference to sock dropped.
787 * 0: continue
788 * 1: repeat lookup - reference dropped while waiting for socket memory.
789 */
790 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
791 long *timeo, struct sock *ssk)
792 {
793 struct netlink_sock *nlk;
794
795 nlk = nlk_sk(sk);
796
797 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
798 test_bit(0, &nlk->state)) {
799 DECLARE_WAITQUEUE(wait, current);
800 if (!*timeo) {
801 if (!ssk || netlink_is_kernel(ssk))
802 netlink_overrun(sk);
803 sock_put(sk);
804 kfree_skb(skb);
805 return -EAGAIN;
806 }
807
808 __set_current_state(TASK_INTERRUPTIBLE);
809 add_wait_queue(&nlk->wait, &wait);
810
811 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
812 test_bit(0, &nlk->state)) &&
813 !sock_flag(sk, SOCK_DEAD))
814 *timeo = schedule_timeout(*timeo);
815
816 __set_current_state(TASK_RUNNING);
817 remove_wait_queue(&nlk->wait, &wait);
818 sock_put(sk);
819
820 if (signal_pending(current)) {
821 kfree_skb(skb);
822 return sock_intr_errno(*timeo);
823 }
824 return 1;
825 }
826 skb_set_owner_r(skb, sk);
827 return 0;
828 }
829
830 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
831 {
832 int len = skb->len;
833
834 skb_queue_tail(&sk->sk_receive_queue, skb);
835 sk->sk_data_ready(sk, len);
836 sock_put(sk);
837 return len;
838 }
839
840 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
841 {
842 kfree_skb(skb);
843 sock_put(sk);
844 }
845
846 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
847 gfp_t allocation)
848 {
849 int delta;
850
851 skb_orphan(skb);
852
853 delta = skb->end - skb->tail;
854 if (delta * 2 < skb->truesize)
855 return skb;
856
857 if (skb_shared(skb)) {
858 struct sk_buff *nskb = skb_clone(skb, allocation);
859 if (!nskb)
860 return skb;
861 kfree_skb(skb);
862 skb = nskb;
863 }
864
865 if (!pskb_expand_head(skb, 0, -delta, allocation))
866 skb->truesize -= delta;
867
868 return skb;
869 }
870
871 static inline void netlink_rcv_wake(struct sock *sk)
872 {
873 struct netlink_sock *nlk = nlk_sk(sk);
874
875 if (skb_queue_empty(&sk->sk_receive_queue))
876 clear_bit(0, &nlk->state);
877 if (!test_bit(0, &nlk->state))
878 wake_up_interruptible(&nlk->wait);
879 }
880
881 static inline int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb)
882 {
883 int ret;
884 struct netlink_sock *nlk = nlk_sk(sk);
885
886 ret = -ECONNREFUSED;
887 if (nlk->netlink_rcv != NULL) {
888 ret = skb->len;
889 skb_set_owner_r(skb, sk);
890 nlk->netlink_rcv(skb);
891 }
892 kfree_skb(skb);
893 sock_put(sk);
894 return ret;
895 }
896
897 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
898 u32 pid, int nonblock)
899 {
900 struct sock *sk;
901 int err;
902 long timeo;
903
904 skb = netlink_trim(skb, gfp_any());
905
906 timeo = sock_sndtimeo(ssk, nonblock);
907 retry:
908 sk = netlink_getsockbypid(ssk, pid);
909 if (IS_ERR(sk)) {
910 kfree_skb(skb);
911 return PTR_ERR(sk);
912 }
913 if (netlink_is_kernel(sk))
914 return netlink_unicast_kernel(sk, skb);
915
916 if (sk_filter(sk, skb)) {
917 err = skb->len;
918 kfree_skb(skb);
919 sock_put(sk);
920 return err;
921 }
922
923 err = netlink_attachskb(sk, skb, &timeo, ssk);
924 if (err == 1)
925 goto retry;
926 if (err)
927 return err;
928
929 return netlink_sendskb(sk, skb);
930 }
931 EXPORT_SYMBOL(netlink_unicast);
932
933 int netlink_has_listeners(struct sock *sk, unsigned int group)
934 {
935 int res = 0;
936 unsigned long *listeners;
937
938 BUG_ON(!netlink_is_kernel(sk));
939
940 rcu_read_lock();
941 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
942
943 if (group - 1 < nl_table[sk->sk_protocol].groups)
944 res = test_bit(group - 1, listeners);
945
946 rcu_read_unlock();
947
948 return res;
949 }
950 EXPORT_SYMBOL_GPL(netlink_has_listeners);
951
952 static inline int netlink_broadcast_deliver(struct sock *sk,
953 struct sk_buff *skb)
954 {
955 struct netlink_sock *nlk = nlk_sk(sk);
956
957 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
958 !test_bit(0, &nlk->state)) {
959 skb_set_owner_r(skb, sk);
960 skb_queue_tail(&sk->sk_receive_queue, skb);
961 sk->sk_data_ready(sk, skb->len);
962 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
963 }
964 return -1;
965 }
966
967 struct netlink_broadcast_data {
968 struct sock *exclude_sk;
969 struct net *net;
970 u32 pid;
971 u32 group;
972 int failure;
973 int delivery_failure;
974 int congested;
975 int delivered;
976 gfp_t allocation;
977 struct sk_buff *skb, *skb2;
978 };
979
980 static inline int do_one_broadcast(struct sock *sk,
981 struct netlink_broadcast_data *p)
982 {
983 struct netlink_sock *nlk = nlk_sk(sk);
984 int val;
985
986 if (p->exclude_sk == sk)
987 goto out;
988
989 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
990 !test_bit(p->group - 1, nlk->groups))
991 goto out;
992
993 if (!net_eq(sock_net(sk), p->net))
994 goto out;
995
996 if (p->failure) {
997 netlink_overrun(sk);
998 goto out;
999 }
1000
1001 sock_hold(sk);
1002 if (p->skb2 == NULL) {
1003 if (skb_shared(p->skb)) {
1004 p->skb2 = skb_clone(p->skb, p->allocation);
1005 } else {
1006 p->skb2 = skb_get(p->skb);
1007 /*
1008 * skb ownership may have been set when
1009 * delivered to a previous socket.
1010 */
1011 skb_orphan(p->skb2);
1012 }
1013 }
1014 if (p->skb2 == NULL) {
1015 netlink_overrun(sk);
1016 /* Clone failed. Notify ALL listeners. */
1017 p->failure = 1;
1018 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1019 p->delivery_failure = 1;
1020 } else if (sk_filter(sk, p->skb2)) {
1021 kfree_skb(p->skb2);
1022 p->skb2 = NULL;
1023 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1024 netlink_overrun(sk);
1025 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1026 p->delivery_failure = 1;
1027 } else {
1028 p->congested |= val;
1029 p->delivered = 1;
1030 p->skb2 = NULL;
1031 }
1032 sock_put(sk);
1033
1034 out:
1035 return 0;
1036 }
1037
1038 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
1039 u32 group, gfp_t allocation)
1040 {
1041 struct net *net = sock_net(ssk);
1042 struct netlink_broadcast_data info;
1043 struct hlist_node *node;
1044 struct sock *sk;
1045
1046 skb = netlink_trim(skb, allocation);
1047
1048 info.exclude_sk = ssk;
1049 info.net = net;
1050 info.pid = pid;
1051 info.group = group;
1052 info.failure = 0;
1053 info.delivery_failure = 0;
1054 info.congested = 0;
1055 info.delivered = 0;
1056 info.allocation = allocation;
1057 info.skb = skb;
1058 info.skb2 = NULL;
1059
1060 /* While we sleep in clone, do not allow to change socket list */
1061
1062 netlink_lock_table();
1063
1064 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1065 do_one_broadcast(sk, &info);
1066
1067 kfree_skb(skb);
1068
1069 netlink_unlock_table();
1070
1071 kfree_skb(info.skb2);
1072
1073 if (info.delivery_failure)
1074 return -ENOBUFS;
1075
1076 if (info.delivered) {
1077 if (info.congested && (allocation & __GFP_WAIT))
1078 yield();
1079 return 0;
1080 }
1081 return -ESRCH;
1082 }
1083 EXPORT_SYMBOL(netlink_broadcast);
1084
1085 struct netlink_set_err_data {
1086 struct sock *exclude_sk;
1087 u32 pid;
1088 u32 group;
1089 int code;
1090 };
1091
1092 static inline int do_one_set_err(struct sock *sk,
1093 struct netlink_set_err_data *p)
1094 {
1095 struct netlink_sock *nlk = nlk_sk(sk);
1096 int ret = 0;
1097
1098 if (sk == p->exclude_sk)
1099 goto out;
1100
1101 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1102 goto out;
1103
1104 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1105 !test_bit(p->group - 1, nlk->groups))
1106 goto out;
1107
1108 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
1109 ret = 1;
1110 goto out;
1111 }
1112
1113 sk->sk_err = p->code;
1114 sk->sk_error_report(sk);
1115 out:
1116 return ret;
1117 }
1118
1119 /**
1120 * netlink_set_err - report error to broadcast listeners
1121 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1122 * @pid: the PID of a process that we want to skip (if any)
1123 * @groups: the broadcast group that will notice the error
1124 * @code: error code, must be negative (as usual in kernelspace)
1125 *
1126 * This function returns the number of broadcast listeners that have set the
1127 * NETLINK_RECV_NO_ENOBUFS socket option.
1128 */
1129 int netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1130 {
1131 struct netlink_set_err_data info;
1132 struct hlist_node *node;
1133 struct sock *sk;
1134 int ret = 0;
1135
1136 info.exclude_sk = ssk;
1137 info.pid = pid;
1138 info.group = group;
1139 /* sk->sk_err wants a positive error value */
1140 info.code = -code;
1141
1142 read_lock(&nl_table_lock);
1143
1144 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1145 ret += do_one_set_err(sk, &info);
1146
1147 read_unlock(&nl_table_lock);
1148 return ret;
1149 }
1150 EXPORT_SYMBOL(netlink_set_err);
1151
1152 /* must be called with netlink table grabbed */
1153 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1154 unsigned int group,
1155 int is_new)
1156 {
1157 int old, new = !!is_new, subscriptions;
1158
1159 old = test_bit(group - 1, nlk->groups);
1160 subscriptions = nlk->subscriptions - old + new;
1161 if (new)
1162 __set_bit(group - 1, nlk->groups);
1163 else
1164 __clear_bit(group - 1, nlk->groups);
1165 netlink_update_subscriptions(&nlk->sk, subscriptions);
1166 netlink_update_listeners(&nlk->sk);
1167 }
1168
1169 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1170 char __user *optval, unsigned int optlen)
1171 {
1172 struct sock *sk = sock->sk;
1173 struct netlink_sock *nlk = nlk_sk(sk);
1174 unsigned int val = 0;
1175 int err;
1176
1177 if (level != SOL_NETLINK)
1178 return -ENOPROTOOPT;
1179
1180 if (optlen >= sizeof(int) &&
1181 get_user(val, (unsigned int __user *)optval))
1182 return -EFAULT;
1183
1184 switch (optname) {
1185 case NETLINK_PKTINFO:
1186 if (val)
1187 nlk->flags |= NETLINK_RECV_PKTINFO;
1188 else
1189 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1190 err = 0;
1191 break;
1192 case NETLINK_ADD_MEMBERSHIP:
1193 case NETLINK_DROP_MEMBERSHIP: {
1194 if (!netlink_capable(sock, NL_NONROOT_RECV))
1195 return -EPERM;
1196 err = netlink_realloc_groups(sk);
1197 if (err)
1198 return err;
1199 if (!val || val - 1 >= nlk->ngroups)
1200 return -EINVAL;
1201 netlink_table_grab();
1202 netlink_update_socket_mc(nlk, val,
1203 optname == NETLINK_ADD_MEMBERSHIP);
1204 netlink_table_ungrab();
1205 err = 0;
1206 break;
1207 }
1208 case NETLINK_BROADCAST_ERROR:
1209 if (val)
1210 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1211 else
1212 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1213 err = 0;
1214 break;
1215 case NETLINK_NO_ENOBUFS:
1216 if (val) {
1217 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1218 clear_bit(0, &nlk->state);
1219 wake_up_interruptible(&nlk->wait);
1220 } else
1221 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1222 err = 0;
1223 break;
1224 default:
1225 err = -ENOPROTOOPT;
1226 }
1227 return err;
1228 }
1229
1230 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1231 char __user *optval, int __user *optlen)
1232 {
1233 struct sock *sk = sock->sk;
1234 struct netlink_sock *nlk = nlk_sk(sk);
1235 int len, val, err;
1236
1237 if (level != SOL_NETLINK)
1238 return -ENOPROTOOPT;
1239
1240 if (get_user(len, optlen))
1241 return -EFAULT;
1242 if (len < 0)
1243 return -EINVAL;
1244
1245 switch (optname) {
1246 case NETLINK_PKTINFO:
1247 if (len < sizeof(int))
1248 return -EINVAL;
1249 len = sizeof(int);
1250 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1251 if (put_user(len, optlen) ||
1252 put_user(val, optval))
1253 return -EFAULT;
1254 err = 0;
1255 break;
1256 case NETLINK_BROADCAST_ERROR:
1257 if (len < sizeof(int))
1258 return -EINVAL;
1259 len = sizeof(int);
1260 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1261 if (put_user(len, optlen) ||
1262 put_user(val, optval))
1263 return -EFAULT;
1264 err = 0;
1265 break;
1266 case NETLINK_NO_ENOBUFS:
1267 if (len < sizeof(int))
1268 return -EINVAL;
1269 len = sizeof(int);
1270 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1271 if (put_user(len, optlen) ||
1272 put_user(val, optval))
1273 return -EFAULT;
1274 err = 0;
1275 break;
1276 default:
1277 err = -ENOPROTOOPT;
1278 }
1279 return err;
1280 }
1281
1282 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1283 {
1284 struct nl_pktinfo info;
1285
1286 info.group = NETLINK_CB(skb).dst_group;
1287 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1288 }
1289
1290 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1291 struct msghdr *msg, size_t len)
1292 {
1293 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1294 struct sock *sk = sock->sk;
1295 struct netlink_sock *nlk = nlk_sk(sk);
1296 struct sockaddr_nl *addr = msg->msg_name;
1297 u32 dst_pid;
1298 u32 dst_group;
1299 struct sk_buff *skb;
1300 int err;
1301 struct scm_cookie scm;
1302
1303 if (msg->msg_flags&MSG_OOB)
1304 return -EOPNOTSUPP;
1305
1306 if (NULL == siocb->scm)
1307 siocb->scm = &scm;
1308 err = scm_send(sock, msg, siocb->scm);
1309 if (err < 0)
1310 return err;
1311
1312 if (msg->msg_namelen) {
1313 if (addr->nl_family != AF_NETLINK)
1314 return -EINVAL;
1315 dst_pid = addr->nl_pid;
1316 dst_group = ffs(addr->nl_groups);
1317 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1318 return -EPERM;
1319 } else {
1320 dst_pid = nlk->dst_pid;
1321 dst_group = nlk->dst_group;
1322 }
1323
1324 if (!nlk->pid) {
1325 err = netlink_autobind(sock);
1326 if (err)
1327 goto out;
1328 }
1329
1330 err = -EMSGSIZE;
1331 if (len > sk->sk_sndbuf - 32)
1332 goto out;
1333 err = -ENOBUFS;
1334 skb = alloc_skb(len, GFP_KERNEL);
1335 if (skb == NULL)
1336 goto out;
1337
1338 NETLINK_CB(skb).pid = nlk->pid;
1339 NETLINK_CB(skb).dst_group = dst_group;
1340 NETLINK_CB(skb).loginuid = audit_get_loginuid(current);
1341 NETLINK_CB(skb).sessionid = audit_get_sessionid(current);
1342 security_task_getsecid(current, &(NETLINK_CB(skb).sid));
1343 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1344
1345 /* What can I do? Netlink is asynchronous, so that
1346 we will have to save current capabilities to
1347 check them, when this message will be delivered
1348 to corresponding kernel module. --ANK (980802)
1349 */
1350
1351 err = -EFAULT;
1352 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1353 kfree_skb(skb);
1354 goto out;
1355 }
1356
1357 err = security_netlink_send(sk, skb);
1358 if (err) {
1359 kfree_skb(skb);
1360 goto out;
1361 }
1362
1363 if (dst_group) {
1364 atomic_inc(&skb->users);
1365 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1366 }
1367 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1368
1369 out:
1370 return err;
1371 }
1372
1373 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1374 struct msghdr *msg, size_t len,
1375 int flags)
1376 {
1377 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1378 struct scm_cookie scm;
1379 struct sock *sk = sock->sk;
1380 struct netlink_sock *nlk = nlk_sk(sk);
1381 int noblock = flags&MSG_DONTWAIT;
1382 size_t copied;
1383 struct sk_buff *skb, *frag __maybe_unused = NULL;
1384 int err;
1385
1386 if (flags&MSG_OOB)
1387 return -EOPNOTSUPP;
1388
1389 copied = 0;
1390
1391 skb = skb_recv_datagram(sk, flags, noblock, &err);
1392 if (skb == NULL)
1393 goto out;
1394
1395 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1396 if (unlikely(skb_shinfo(skb)->frag_list)) {
1397 bool need_compat = !!(flags & MSG_CMSG_COMPAT);
1398
1399 /*
1400 * If this skb has a frag_list, then here that means that
1401 * we will have to use the frag_list skb for compat tasks
1402 * and the regular skb for non-compat tasks.
1403 *
1404 * The skb might (and likely will) be cloned, so we can't
1405 * just reset frag_list and go on with things -- we need to
1406 * keep that. For the compat case that's easy -- simply get
1407 * a reference to the compat skb and free the regular one
1408 * including the frag. For the non-compat case, we need to
1409 * avoid sending the frag to the user -- so assign NULL but
1410 * restore it below before freeing the skb.
1411 */
1412 if (need_compat) {
1413 struct sk_buff *compskb = skb_shinfo(skb)->frag_list;
1414 skb_get(compskb);
1415 kfree_skb(skb);
1416 skb = compskb;
1417 } else {
1418 frag = skb_shinfo(skb)->frag_list;
1419 skb_shinfo(skb)->frag_list = NULL;
1420 }
1421 }
1422 #endif
1423
1424 msg->msg_namelen = 0;
1425
1426 copied = skb->len;
1427 if (len < copied) {
1428 msg->msg_flags |= MSG_TRUNC;
1429 copied = len;
1430 }
1431
1432 skb_reset_transport_header(skb);
1433 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1434
1435 if (msg->msg_name) {
1436 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1437 addr->nl_family = AF_NETLINK;
1438 addr->nl_pad = 0;
1439 addr->nl_pid = NETLINK_CB(skb).pid;
1440 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1441 msg->msg_namelen = sizeof(*addr);
1442 }
1443
1444 if (nlk->flags & NETLINK_RECV_PKTINFO)
1445 netlink_cmsg_recv_pktinfo(msg, skb);
1446
1447 if (NULL == siocb->scm) {
1448 memset(&scm, 0, sizeof(scm));
1449 siocb->scm = &scm;
1450 }
1451 siocb->scm->creds = *NETLINK_CREDS(skb);
1452 if (flags & MSG_TRUNC)
1453 copied = skb->len;
1454
1455 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1456 skb_shinfo(skb)->frag_list = frag;
1457 #endif
1458
1459 skb_free_datagram(sk, skb);
1460
1461 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1462 netlink_dump(sk);
1463
1464 scm_recv(sock, msg, siocb->scm, flags);
1465 out:
1466 netlink_rcv_wake(sk);
1467 return err ? : copied;
1468 }
1469
1470 static void netlink_data_ready(struct sock *sk, int len)
1471 {
1472 BUG();
1473 }
1474
1475 /*
1476 * We export these functions to other modules. They provide a
1477 * complete set of kernel non-blocking support for message
1478 * queueing.
1479 */
1480
1481 struct sock *
1482 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1483 void (*input)(struct sk_buff *skb),
1484 struct mutex *cb_mutex, struct module *module)
1485 {
1486 struct socket *sock;
1487 struct sock *sk;
1488 struct netlink_sock *nlk;
1489 unsigned long *listeners = NULL;
1490
1491 BUG_ON(!nl_table);
1492
1493 if (unit < 0 || unit >= MAX_LINKS)
1494 return NULL;
1495
1496 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1497 return NULL;
1498
1499 /*
1500 * We have to just have a reference on the net from sk, but don't
1501 * get_net it. Besides, we cannot get and then put the net here.
1502 * So we create one inside init_net and the move it to net.
1503 */
1504
1505 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1506 goto out_sock_release_nosk;
1507
1508 sk = sock->sk;
1509 sk_change_net(sk, net);
1510
1511 if (groups < 32)
1512 groups = 32;
1513
1514 listeners = kzalloc(NLGRPSZ(groups) + sizeof(struct listeners_rcu_head),
1515 GFP_KERNEL);
1516 if (!listeners)
1517 goto out_sock_release;
1518
1519 sk->sk_data_ready = netlink_data_ready;
1520 if (input)
1521 nlk_sk(sk)->netlink_rcv = input;
1522
1523 if (netlink_insert(sk, net, 0))
1524 goto out_sock_release;
1525
1526 nlk = nlk_sk(sk);
1527 nlk->flags |= NETLINK_KERNEL_SOCKET;
1528
1529 netlink_table_grab();
1530 if (!nl_table[unit].registered) {
1531 nl_table[unit].groups = groups;
1532 nl_table[unit].listeners = listeners;
1533 nl_table[unit].cb_mutex = cb_mutex;
1534 nl_table[unit].module = module;
1535 nl_table[unit].registered = 1;
1536 } else {
1537 kfree(listeners);
1538 nl_table[unit].registered++;
1539 }
1540 netlink_table_ungrab();
1541 return sk;
1542
1543 out_sock_release:
1544 kfree(listeners);
1545 netlink_kernel_release(sk);
1546 return NULL;
1547
1548 out_sock_release_nosk:
1549 sock_release(sock);
1550 return NULL;
1551 }
1552 EXPORT_SYMBOL(netlink_kernel_create);
1553
1554
1555 void
1556 netlink_kernel_release(struct sock *sk)
1557 {
1558 sk_release_kernel(sk);
1559 }
1560 EXPORT_SYMBOL(netlink_kernel_release);
1561
1562
1563 static void netlink_free_old_listeners(struct rcu_head *rcu_head)
1564 {
1565 struct listeners_rcu_head *lrh;
1566
1567 lrh = container_of(rcu_head, struct listeners_rcu_head, rcu_head);
1568 kfree(lrh->ptr);
1569 }
1570
1571 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1572 {
1573 unsigned long *listeners, *old = NULL;
1574 struct listeners_rcu_head *old_rcu_head;
1575 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1576
1577 if (groups < 32)
1578 groups = 32;
1579
1580 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1581 listeners = kzalloc(NLGRPSZ(groups) +
1582 sizeof(struct listeners_rcu_head),
1583 GFP_ATOMIC);
1584 if (!listeners)
1585 return -ENOMEM;
1586 old = tbl->listeners;
1587 memcpy(listeners, old, NLGRPSZ(tbl->groups));
1588 rcu_assign_pointer(tbl->listeners, listeners);
1589 /*
1590 * Free the old memory after an RCU grace period so we
1591 * don't leak it. We use call_rcu() here in order to be
1592 * able to call this function from atomic contexts. The
1593 * allocation of this memory will have reserved enough
1594 * space for struct listeners_rcu_head at the end.
1595 */
1596 old_rcu_head = (void *)(tbl->listeners +
1597 NLGRPLONGS(tbl->groups));
1598 old_rcu_head->ptr = old;
1599 call_rcu(&old_rcu_head->rcu_head, netlink_free_old_listeners);
1600 }
1601 tbl->groups = groups;
1602
1603 return 0;
1604 }
1605
1606 /**
1607 * netlink_change_ngroups - change number of multicast groups
1608 *
1609 * This changes the number of multicast groups that are available
1610 * on a certain netlink family. Note that it is not possible to
1611 * change the number of groups to below 32. Also note that it does
1612 * not implicitly call netlink_clear_multicast_users() when the
1613 * number of groups is reduced.
1614 *
1615 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1616 * @groups: The new number of groups.
1617 */
1618 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1619 {
1620 int err;
1621
1622 netlink_table_grab();
1623 err = __netlink_change_ngroups(sk, groups);
1624 netlink_table_ungrab();
1625
1626 return err;
1627 }
1628
1629 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1630 {
1631 struct sock *sk;
1632 struct hlist_node *node;
1633 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1634
1635 sk_for_each_bound(sk, node, &tbl->mc_list)
1636 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1637 }
1638
1639 /**
1640 * netlink_clear_multicast_users - kick off multicast listeners
1641 *
1642 * This function removes all listeners from the given group.
1643 * @ksk: The kernel netlink socket, as returned by
1644 * netlink_kernel_create().
1645 * @group: The multicast group to clear.
1646 */
1647 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1648 {
1649 netlink_table_grab();
1650 __netlink_clear_multicast_users(ksk, group);
1651 netlink_table_ungrab();
1652 }
1653
1654 void netlink_set_nonroot(int protocol, unsigned int flags)
1655 {
1656 if ((unsigned int)protocol < MAX_LINKS)
1657 nl_table[protocol].nl_nonroot = flags;
1658 }
1659 EXPORT_SYMBOL(netlink_set_nonroot);
1660
1661 static void netlink_destroy_callback(struct netlink_callback *cb)
1662 {
1663 kfree_skb(cb->skb);
1664 kfree(cb);
1665 }
1666
1667 /*
1668 * It looks a bit ugly.
1669 * It would be better to create kernel thread.
1670 */
1671
1672 static int netlink_dump(struct sock *sk)
1673 {
1674 struct netlink_sock *nlk = nlk_sk(sk);
1675 struct netlink_callback *cb;
1676 struct sk_buff *skb;
1677 struct nlmsghdr *nlh;
1678 int len, err = -ENOBUFS;
1679
1680 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1681 if (!skb)
1682 goto errout;
1683
1684 mutex_lock(nlk->cb_mutex);
1685
1686 cb = nlk->cb;
1687 if (cb == NULL) {
1688 err = -EINVAL;
1689 goto errout_skb;
1690 }
1691
1692 len = cb->dump(skb, cb);
1693
1694 if (len > 0) {
1695 mutex_unlock(nlk->cb_mutex);
1696
1697 if (sk_filter(sk, skb))
1698 kfree_skb(skb);
1699 else {
1700 skb_queue_tail(&sk->sk_receive_queue, skb);
1701 sk->sk_data_ready(sk, skb->len);
1702 }
1703 return 0;
1704 }
1705
1706 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1707 if (!nlh)
1708 goto errout_skb;
1709
1710 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1711
1712 if (sk_filter(sk, skb))
1713 kfree_skb(skb);
1714 else {
1715 skb_queue_tail(&sk->sk_receive_queue, skb);
1716 sk->sk_data_ready(sk, skb->len);
1717 }
1718
1719 if (cb->done)
1720 cb->done(cb);
1721 nlk->cb = NULL;
1722 mutex_unlock(nlk->cb_mutex);
1723
1724 netlink_destroy_callback(cb);
1725 return 0;
1726
1727 errout_skb:
1728 mutex_unlock(nlk->cb_mutex);
1729 kfree_skb(skb);
1730 errout:
1731 return err;
1732 }
1733
1734 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1735 const struct nlmsghdr *nlh,
1736 int (*dump)(struct sk_buff *skb,
1737 struct netlink_callback *),
1738 int (*done)(struct netlink_callback *))
1739 {
1740 struct netlink_callback *cb;
1741 struct sock *sk;
1742 struct netlink_sock *nlk;
1743
1744 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1745 if (cb == NULL)
1746 return -ENOBUFS;
1747
1748 cb->dump = dump;
1749 cb->done = done;
1750 cb->nlh = nlh;
1751 atomic_inc(&skb->users);
1752 cb->skb = skb;
1753
1754 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1755 if (sk == NULL) {
1756 netlink_destroy_callback(cb);
1757 return -ECONNREFUSED;
1758 }
1759 nlk = nlk_sk(sk);
1760 /* A dump is in progress... */
1761 mutex_lock(nlk->cb_mutex);
1762 if (nlk->cb) {
1763 mutex_unlock(nlk->cb_mutex);
1764 netlink_destroy_callback(cb);
1765 sock_put(sk);
1766 return -EBUSY;
1767 }
1768 nlk->cb = cb;
1769 mutex_unlock(nlk->cb_mutex);
1770
1771 netlink_dump(sk);
1772 sock_put(sk);
1773
1774 /* We successfully started a dump, by returning -EINTR we
1775 * signal not to send ACK even if it was requested.
1776 */
1777 return -EINTR;
1778 }
1779 EXPORT_SYMBOL(netlink_dump_start);
1780
1781 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1782 {
1783 struct sk_buff *skb;
1784 struct nlmsghdr *rep;
1785 struct nlmsgerr *errmsg;
1786 size_t payload = sizeof(*errmsg);
1787
1788 /* error messages get the original request appened */
1789 if (err)
1790 payload += nlmsg_len(nlh);
1791
1792 skb = nlmsg_new(payload, GFP_KERNEL);
1793 if (!skb) {
1794 struct sock *sk;
1795
1796 sk = netlink_lookup(sock_net(in_skb->sk),
1797 in_skb->sk->sk_protocol,
1798 NETLINK_CB(in_skb).pid);
1799 if (sk) {
1800 sk->sk_err = ENOBUFS;
1801 sk->sk_error_report(sk);
1802 sock_put(sk);
1803 }
1804 return;
1805 }
1806
1807 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1808 NLMSG_ERROR, payload, 0);
1809 errmsg = nlmsg_data(rep);
1810 errmsg->error = err;
1811 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1812 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1813 }
1814 EXPORT_SYMBOL(netlink_ack);
1815
1816 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1817 struct nlmsghdr *))
1818 {
1819 struct nlmsghdr *nlh;
1820 int err;
1821
1822 while (skb->len >= nlmsg_total_size(0)) {
1823 int msglen;
1824
1825 nlh = nlmsg_hdr(skb);
1826 err = 0;
1827
1828 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1829 return 0;
1830
1831 /* Only requests are handled by the kernel */
1832 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1833 goto ack;
1834
1835 /* Skip control messages */
1836 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1837 goto ack;
1838
1839 err = cb(skb, nlh);
1840 if (err == -EINTR)
1841 goto skip;
1842
1843 ack:
1844 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1845 netlink_ack(skb, nlh, err);
1846
1847 skip:
1848 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1849 if (msglen > skb->len)
1850 msglen = skb->len;
1851 skb_pull(skb, msglen);
1852 }
1853
1854 return 0;
1855 }
1856 EXPORT_SYMBOL(netlink_rcv_skb);
1857
1858 /**
1859 * nlmsg_notify - send a notification netlink message
1860 * @sk: netlink socket to use
1861 * @skb: notification message
1862 * @pid: destination netlink pid for reports or 0
1863 * @group: destination multicast group or 0
1864 * @report: 1 to report back, 0 to disable
1865 * @flags: allocation flags
1866 */
1867 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1868 unsigned int group, int report, gfp_t flags)
1869 {
1870 int err = 0;
1871
1872 if (group) {
1873 int exclude_pid = 0;
1874
1875 if (report) {
1876 atomic_inc(&skb->users);
1877 exclude_pid = pid;
1878 }
1879
1880 /* errors reported via destination sk->sk_err, but propagate
1881 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1882 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1883 }
1884
1885 if (report) {
1886 int err2;
1887
1888 err2 = nlmsg_unicast(sk, skb, pid);
1889 if (!err || err == -ESRCH)
1890 err = err2;
1891 }
1892
1893 return err;
1894 }
1895 EXPORT_SYMBOL(nlmsg_notify);
1896
1897 #ifdef CONFIG_PROC_FS
1898 struct nl_seq_iter {
1899 struct seq_net_private p;
1900 int link;
1901 int hash_idx;
1902 };
1903
1904 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1905 {
1906 struct nl_seq_iter *iter = seq->private;
1907 int i, j;
1908 struct sock *s;
1909 struct hlist_node *node;
1910 loff_t off = 0;
1911
1912 for (i = 0; i < MAX_LINKS; i++) {
1913 struct nl_pid_hash *hash = &nl_table[i].hash;
1914
1915 for (j = 0; j <= hash->mask; j++) {
1916 sk_for_each(s, node, &hash->table[j]) {
1917 if (sock_net(s) != seq_file_net(seq))
1918 continue;
1919 if (off == pos) {
1920 iter->link = i;
1921 iter->hash_idx = j;
1922 return s;
1923 }
1924 ++off;
1925 }
1926 }
1927 }
1928 return NULL;
1929 }
1930
1931 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1932 __acquires(nl_table_lock)
1933 {
1934 read_lock(&nl_table_lock);
1935 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1936 }
1937
1938 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1939 {
1940 struct sock *s;
1941 struct nl_seq_iter *iter;
1942 int i, j;
1943
1944 ++*pos;
1945
1946 if (v == SEQ_START_TOKEN)
1947 return netlink_seq_socket_idx(seq, 0);
1948
1949 iter = seq->private;
1950 s = v;
1951 do {
1952 s = sk_next(s);
1953 } while (s && sock_net(s) != seq_file_net(seq));
1954 if (s)
1955 return s;
1956
1957 i = iter->link;
1958 j = iter->hash_idx + 1;
1959
1960 do {
1961 struct nl_pid_hash *hash = &nl_table[i].hash;
1962
1963 for (; j <= hash->mask; j++) {
1964 s = sk_head(&hash->table[j]);
1965 while (s && sock_net(s) != seq_file_net(seq))
1966 s = sk_next(s);
1967 if (s) {
1968 iter->link = i;
1969 iter->hash_idx = j;
1970 return s;
1971 }
1972 }
1973
1974 j = 0;
1975 } while (++i < MAX_LINKS);
1976
1977 return NULL;
1978 }
1979
1980 static void netlink_seq_stop(struct seq_file *seq, void *v)
1981 __releases(nl_table_lock)
1982 {
1983 read_unlock(&nl_table_lock);
1984 }
1985
1986
1987 static int netlink_seq_show(struct seq_file *seq, void *v)
1988 {
1989 if (v == SEQ_START_TOKEN)
1990 seq_puts(seq,
1991 "sk Eth Pid Groups "
1992 "Rmem Wmem Dump Locks Drops\n");
1993 else {
1994 struct sock *s = v;
1995 struct netlink_sock *nlk = nlk_sk(s);
1996
1997 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %-8d %-8d\n",
1998 s,
1999 s->sk_protocol,
2000 nlk->pid,
2001 nlk->groups ? (u32)nlk->groups[0] : 0,
2002 sk_rmem_alloc_get(s),
2003 sk_wmem_alloc_get(s),
2004 nlk->cb,
2005 atomic_read(&s->sk_refcnt),
2006 atomic_read(&s->sk_drops)
2007 );
2008
2009 }
2010 return 0;
2011 }
2012
2013 static const struct seq_operations netlink_seq_ops = {
2014 .start = netlink_seq_start,
2015 .next = netlink_seq_next,
2016 .stop = netlink_seq_stop,
2017 .show = netlink_seq_show,
2018 };
2019
2020
2021 static int netlink_seq_open(struct inode *inode, struct file *file)
2022 {
2023 return seq_open_net(inode, file, &netlink_seq_ops,
2024 sizeof(struct nl_seq_iter));
2025 }
2026
2027 static const struct file_operations netlink_seq_fops = {
2028 .owner = THIS_MODULE,
2029 .open = netlink_seq_open,
2030 .read = seq_read,
2031 .llseek = seq_lseek,
2032 .release = seq_release_net,
2033 };
2034
2035 #endif
2036
2037 int netlink_register_notifier(struct notifier_block *nb)
2038 {
2039 return atomic_notifier_chain_register(&netlink_chain, nb);
2040 }
2041 EXPORT_SYMBOL(netlink_register_notifier);
2042
2043 int netlink_unregister_notifier(struct notifier_block *nb)
2044 {
2045 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2046 }
2047 EXPORT_SYMBOL(netlink_unregister_notifier);
2048
2049 static const struct proto_ops netlink_ops = {
2050 .family = PF_NETLINK,
2051 .owner = THIS_MODULE,
2052 .release = netlink_release,
2053 .bind = netlink_bind,
2054 .connect = netlink_connect,
2055 .socketpair = sock_no_socketpair,
2056 .accept = sock_no_accept,
2057 .getname = netlink_getname,
2058 .poll = datagram_poll,
2059 .ioctl = sock_no_ioctl,
2060 .listen = sock_no_listen,
2061 .shutdown = sock_no_shutdown,
2062 .setsockopt = netlink_setsockopt,
2063 .getsockopt = netlink_getsockopt,
2064 .sendmsg = netlink_sendmsg,
2065 .recvmsg = netlink_recvmsg,
2066 .mmap = sock_no_mmap,
2067 .sendpage = sock_no_sendpage,
2068 };
2069
2070 static const struct net_proto_family netlink_family_ops = {
2071 .family = PF_NETLINK,
2072 .create = netlink_create,
2073 .owner = THIS_MODULE, /* for consistency 8) */
2074 };
2075
2076 static int __net_init netlink_net_init(struct net *net)
2077 {
2078 #ifdef CONFIG_PROC_FS
2079 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2080 return -ENOMEM;
2081 #endif
2082 return 0;
2083 }
2084
2085 static void __net_exit netlink_net_exit(struct net *net)
2086 {
2087 #ifdef CONFIG_PROC_FS
2088 proc_net_remove(net, "netlink");
2089 #endif
2090 }
2091
2092 static struct pernet_operations __net_initdata netlink_net_ops = {
2093 .init = netlink_net_init,
2094 .exit = netlink_net_exit,
2095 };
2096
2097 static int __init netlink_proto_init(void)
2098 {
2099 struct sk_buff *dummy_skb;
2100 int i;
2101 unsigned long limit;
2102 unsigned int order;
2103 int err = proto_register(&netlink_proto, 0);
2104
2105 if (err != 0)
2106 goto out;
2107
2108 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2109
2110 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2111 if (!nl_table)
2112 goto panic;
2113
2114 if (totalram_pages >= (128 * 1024))
2115 limit = totalram_pages >> (21 - PAGE_SHIFT);
2116 else
2117 limit = totalram_pages >> (23 - PAGE_SHIFT);
2118
2119 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2120 limit = (1UL << order) / sizeof(struct hlist_head);
2121 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2122
2123 for (i = 0; i < MAX_LINKS; i++) {
2124 struct nl_pid_hash *hash = &nl_table[i].hash;
2125
2126 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
2127 if (!hash->table) {
2128 while (i-- > 0)
2129 nl_pid_hash_free(nl_table[i].hash.table,
2130 1 * sizeof(*hash->table));
2131 kfree(nl_table);
2132 goto panic;
2133 }
2134 hash->max_shift = order;
2135 hash->shift = 0;
2136 hash->mask = 0;
2137 hash->rehash_time = jiffies;
2138 }
2139
2140 sock_register(&netlink_family_ops);
2141 register_pernet_subsys(&netlink_net_ops);
2142 /* The netlink device handler may be needed early. */
2143 rtnetlink_init();
2144 out:
2145 return err;
2146 panic:
2147 panic("netlink_init: Cannot allocate nl_table\n");
2148 }
2149
2150 core_initcall(netlink_proto_init);
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree