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V4L/DVB: dvb: fix sparse warnings
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / netlink / af_netlink.c
blob4c5972ba8c78c00bb35519cae8e927ae84e8a1d0
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
1097 if (sk == p->exclude_sk)
1098 goto out;
1099
1100 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1101 goto out;
1102
1103 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1104 !test_bit(p->group - 1, nlk->groups))
1105 goto out;
1106
1107 sk->sk_err = p->code;
1108 sk->sk_error_report(sk);
1109 out:
1110 return 0;
1111 }
1112
1113 /**
1114 * netlink_set_err - report error to broadcast listeners
1115 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1116 * @pid: the PID of a process that we want to skip (if any)
1117 * @groups: the broadcast group that will notice the error
1118 * @code: error code, must be negative (as usual in kernelspace)
1119 */
1120 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1121 {
1122 struct netlink_set_err_data info;
1123 struct hlist_node *node;
1124 struct sock *sk;
1125
1126 info.exclude_sk = ssk;
1127 info.pid = pid;
1128 info.group = group;
1129 /* sk->sk_err wants a positive error value */
1130 info.code = -code;
1131
1132 read_lock(&nl_table_lock);
1133
1134 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1135 do_one_set_err(sk, &info);
1136
1137 read_unlock(&nl_table_lock);
1138 }
1139 EXPORT_SYMBOL(netlink_set_err);
1140
1141 /* must be called with netlink table grabbed */
1142 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1143 unsigned int group,
1144 int is_new)
1145 {
1146 int old, new = !!is_new, subscriptions;
1147
1148 old = test_bit(group - 1, nlk->groups);
1149 subscriptions = nlk->subscriptions - old + new;
1150 if (new)
1151 __set_bit(group - 1, nlk->groups);
1152 else
1153 __clear_bit(group - 1, nlk->groups);
1154 netlink_update_subscriptions(&nlk->sk, subscriptions);
1155 netlink_update_listeners(&nlk->sk);
1156 }
1157
1158 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1159 char __user *optval, unsigned int optlen)
1160 {
1161 struct sock *sk = sock->sk;
1162 struct netlink_sock *nlk = nlk_sk(sk);
1163 unsigned int val = 0;
1164 int err;
1165
1166 if (level != SOL_NETLINK)
1167 return -ENOPROTOOPT;
1168
1169 if (optlen >= sizeof(int) &&
1170 get_user(val, (unsigned int __user *)optval))
1171 return -EFAULT;
1172
1173 switch (optname) {
1174 case NETLINK_PKTINFO:
1175 if (val)
1176 nlk->flags |= NETLINK_RECV_PKTINFO;
1177 else
1178 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1179 err = 0;
1180 break;
1181 case NETLINK_ADD_MEMBERSHIP:
1182 case NETLINK_DROP_MEMBERSHIP: {
1183 if (!netlink_capable(sock, NL_NONROOT_RECV))
1184 return -EPERM;
1185 err = netlink_realloc_groups(sk);
1186 if (err)
1187 return err;
1188 if (!val || val - 1 >= nlk->ngroups)
1189 return -EINVAL;
1190 netlink_table_grab();
1191 netlink_update_socket_mc(nlk, val,
1192 optname == NETLINK_ADD_MEMBERSHIP);
1193 netlink_table_ungrab();
1194 err = 0;
1195 break;
1196 }
1197 case NETLINK_BROADCAST_ERROR:
1198 if (val)
1199 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1200 else
1201 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1202 err = 0;
1203 break;
1204 case NETLINK_NO_ENOBUFS:
1205 if (val) {
1206 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1207 clear_bit(0, &nlk->state);
1208 wake_up_interruptible(&nlk->wait);
1209 } else
1210 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1211 err = 0;
1212 break;
1213 default:
1214 err = -ENOPROTOOPT;
1215 }
1216 return err;
1217 }
1218
1219 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1220 char __user *optval, int __user *optlen)
1221 {
1222 struct sock *sk = sock->sk;
1223 struct netlink_sock *nlk = nlk_sk(sk);
1224 int len, val, err;
1225
1226 if (level != SOL_NETLINK)
1227 return -ENOPROTOOPT;
1228
1229 if (get_user(len, optlen))
1230 return -EFAULT;
1231 if (len < 0)
1232 return -EINVAL;
1233
1234 switch (optname) {
1235 case NETLINK_PKTINFO:
1236 if (len < sizeof(int))
1237 return -EINVAL;
1238 len = sizeof(int);
1239 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1240 if (put_user(len, optlen) ||
1241 put_user(val, optval))
1242 return -EFAULT;
1243 err = 0;
1244 break;
1245 case NETLINK_BROADCAST_ERROR:
1246 if (len < sizeof(int))
1247 return -EINVAL;
1248 len = sizeof(int);
1249 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1250 if (put_user(len, optlen) ||
1251 put_user(val, optval))
1252 return -EFAULT;
1253 err = 0;
1254 break;
1255 case NETLINK_NO_ENOBUFS:
1256 if (len < sizeof(int))
1257 return -EINVAL;
1258 len = sizeof(int);
1259 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1260 if (put_user(len, optlen) ||
1261 put_user(val, optval))
1262 return -EFAULT;
1263 err = 0;
1264 break;
1265 default:
1266 err = -ENOPROTOOPT;
1267 }
1268 return err;
1269 }
1270
1271 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1272 {
1273 struct nl_pktinfo info;
1274
1275 info.group = NETLINK_CB(skb).dst_group;
1276 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1277 }
1278
1279 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1280 struct msghdr *msg, size_t len)
1281 {
1282 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1283 struct sock *sk = sock->sk;
1284 struct netlink_sock *nlk = nlk_sk(sk);
1285 struct sockaddr_nl *addr = msg->msg_name;
1286 u32 dst_pid;
1287 u32 dst_group;
1288 struct sk_buff *skb;
1289 int err;
1290 struct scm_cookie scm;
1291
1292 if (msg->msg_flags&MSG_OOB)
1293 return -EOPNOTSUPP;
1294
1295 if (NULL == siocb->scm)
1296 siocb->scm = &scm;
1297 err = scm_send(sock, msg, siocb->scm);
1298 if (err < 0)
1299 return err;
1300
1301 if (msg->msg_namelen) {
1302 if (addr->nl_family != AF_NETLINK)
1303 return -EINVAL;
1304 dst_pid = addr->nl_pid;
1305 dst_group = ffs(addr->nl_groups);
1306 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1307 return -EPERM;
1308 } else {
1309 dst_pid = nlk->dst_pid;
1310 dst_group = nlk->dst_group;
1311 }
1312
1313 if (!nlk->pid) {
1314 err = netlink_autobind(sock);
1315 if (err)
1316 goto out;
1317 }
1318
1319 err = -EMSGSIZE;
1320 if (len > sk->sk_sndbuf - 32)
1321 goto out;
1322 err = -ENOBUFS;
1323 skb = alloc_skb(len, GFP_KERNEL);
1324 if (skb == NULL)
1325 goto out;
1326
1327 NETLINK_CB(skb).pid = nlk->pid;
1328 NETLINK_CB(skb).dst_group = dst_group;
1329 NETLINK_CB(skb).loginuid = audit_get_loginuid(current);
1330 NETLINK_CB(skb).sessionid = audit_get_sessionid(current);
1331 security_task_getsecid(current, &(NETLINK_CB(skb).sid));
1332 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1333
1334 /* What can I do? Netlink is asynchronous, so that
1335 we will have to save current capabilities to
1336 check them, when this message will be delivered
1337 to corresponding kernel module. --ANK (980802)
1338 */
1339
1340 err = -EFAULT;
1341 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1342 kfree_skb(skb);
1343 goto out;
1344 }
1345
1346 err = security_netlink_send(sk, skb);
1347 if (err) {
1348 kfree_skb(skb);
1349 goto out;
1350 }
1351
1352 if (dst_group) {
1353 atomic_inc(&skb->users);
1354 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1355 }
1356 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1357
1358 out:
1359 return err;
1360 }
1361
1362 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1363 struct msghdr *msg, size_t len,
1364 int flags)
1365 {
1366 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1367 struct scm_cookie scm;
1368 struct sock *sk = sock->sk;
1369 struct netlink_sock *nlk = nlk_sk(sk);
1370 int noblock = flags&MSG_DONTWAIT;
1371 size_t copied;
1372 struct sk_buff *skb, *frag __maybe_unused = NULL;
1373 int err;
1374
1375 if (flags&MSG_OOB)
1376 return -EOPNOTSUPP;
1377
1378 copied = 0;
1379
1380 skb = skb_recv_datagram(sk, flags, noblock, &err);
1381 if (skb == NULL)
1382 goto out;
1383
1384 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1385 if (unlikely(skb_shinfo(skb)->frag_list)) {
1386 bool need_compat = !!(flags & MSG_CMSG_COMPAT);
1387
1388 /*
1389 * If this skb has a frag_list, then here that means that
1390 * we will have to use the frag_list skb for compat tasks
1391 * and the regular skb for non-compat tasks.
1392 *
1393 * The skb might (and likely will) be cloned, so we can't
1394 * just reset frag_list and go on with things -- we need to
1395 * keep that. For the compat case that's easy -- simply get
1396 * a reference to the compat skb and free the regular one
1397 * including the frag. For the non-compat case, we need to
1398 * avoid sending the frag to the user -- so assign NULL but
1399 * restore it below before freeing the skb.
1400 */
1401 if (need_compat) {
1402 struct sk_buff *compskb = skb_shinfo(skb)->frag_list;
1403 skb_get(compskb);
1404 kfree_skb(skb);
1405 skb = compskb;
1406 } else {
1407 frag = skb_shinfo(skb)->frag_list;
1408 skb_shinfo(skb)->frag_list = NULL;
1409 }
1410 }
1411 #endif
1412
1413 msg->msg_namelen = 0;
1414
1415 copied = skb->len;
1416 if (len < copied) {
1417 msg->msg_flags |= MSG_TRUNC;
1418 copied = len;
1419 }
1420
1421 skb_reset_transport_header(skb);
1422 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1423
1424 if (msg->msg_name) {
1425 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1426 addr->nl_family = AF_NETLINK;
1427 addr->nl_pad = 0;
1428 addr->nl_pid = NETLINK_CB(skb).pid;
1429 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1430 msg->msg_namelen = sizeof(*addr);
1431 }
1432
1433 if (nlk->flags & NETLINK_RECV_PKTINFO)
1434 netlink_cmsg_recv_pktinfo(msg, skb);
1435
1436 if (NULL == siocb->scm) {
1437 memset(&scm, 0, sizeof(scm));
1438 siocb->scm = &scm;
1439 }
1440 siocb->scm->creds = *NETLINK_CREDS(skb);
1441 if (flags & MSG_TRUNC)
1442 copied = skb->len;
1443
1444 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1445 skb_shinfo(skb)->frag_list = frag;
1446 #endif
1447
1448 skb_free_datagram(sk, skb);
1449
1450 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1451 netlink_dump(sk);
1452
1453 scm_recv(sock, msg, siocb->scm, flags);
1454 out:
1455 netlink_rcv_wake(sk);
1456 return err ? : copied;
1457 }
1458
1459 static void netlink_data_ready(struct sock *sk, int len)
1460 {
1461 BUG();
1462 }
1463
1464 /*
1465 * We export these functions to other modules. They provide a
1466 * complete set of kernel non-blocking support for message
1467 * queueing.
1468 */
1469
1470 struct sock *
1471 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1472 void (*input)(struct sk_buff *skb),
1473 struct mutex *cb_mutex, struct module *module)
1474 {
1475 struct socket *sock;
1476 struct sock *sk;
1477 struct netlink_sock *nlk;
1478 unsigned long *listeners = NULL;
1479
1480 BUG_ON(!nl_table);
1481
1482 if (unit < 0 || unit >= MAX_LINKS)
1483 return NULL;
1484
1485 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1486 return NULL;
1487
1488 /*
1489 * We have to just have a reference on the net from sk, but don't
1490 * get_net it. Besides, we cannot get and then put the net here.
1491 * So we create one inside init_net and the move it to net.
1492 */
1493
1494 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1495 goto out_sock_release_nosk;
1496
1497 sk = sock->sk;
1498 sk_change_net(sk, net);
1499
1500 if (groups < 32)
1501 groups = 32;
1502
1503 listeners = kzalloc(NLGRPSZ(groups) + sizeof(struct listeners_rcu_head),
1504 GFP_KERNEL);
1505 if (!listeners)
1506 goto out_sock_release;
1507
1508 sk->sk_data_ready = netlink_data_ready;
1509 if (input)
1510 nlk_sk(sk)->netlink_rcv = input;
1511
1512 if (netlink_insert(sk, net, 0))
1513 goto out_sock_release;
1514
1515 nlk = nlk_sk(sk);
1516 nlk->flags |= NETLINK_KERNEL_SOCKET;
1517
1518 netlink_table_grab();
1519 if (!nl_table[unit].registered) {
1520 nl_table[unit].groups = groups;
1521 nl_table[unit].listeners = listeners;
1522 nl_table[unit].cb_mutex = cb_mutex;
1523 nl_table[unit].module = module;
1524 nl_table[unit].registered = 1;
1525 } else {
1526 kfree(listeners);
1527 nl_table[unit].registered++;
1528 }
1529 netlink_table_ungrab();
1530 return sk;
1531
1532 out_sock_release:
1533 kfree(listeners);
1534 netlink_kernel_release(sk);
1535 return NULL;
1536
1537 out_sock_release_nosk:
1538 sock_release(sock);
1539 return NULL;
1540 }
1541 EXPORT_SYMBOL(netlink_kernel_create);
1542
1543
1544 void
1545 netlink_kernel_release(struct sock *sk)
1546 {
1547 sk_release_kernel(sk);
1548 }
1549 EXPORT_SYMBOL(netlink_kernel_release);
1550
1551
1552 static void netlink_free_old_listeners(struct rcu_head *rcu_head)
1553 {
1554 struct listeners_rcu_head *lrh;
1555
1556 lrh = container_of(rcu_head, struct listeners_rcu_head, rcu_head);
1557 kfree(lrh->ptr);
1558 }
1559
1560 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1561 {
1562 unsigned long *listeners, *old = NULL;
1563 struct listeners_rcu_head *old_rcu_head;
1564 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1565
1566 if (groups < 32)
1567 groups = 32;
1568
1569 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1570 listeners = kzalloc(NLGRPSZ(groups) +
1571 sizeof(struct listeners_rcu_head),
1572 GFP_ATOMIC);
1573 if (!listeners)
1574 return -ENOMEM;
1575 old = tbl->listeners;
1576 memcpy(listeners, old, NLGRPSZ(tbl->groups));
1577 rcu_assign_pointer(tbl->listeners, listeners);
1578 /*
1579 * Free the old memory after an RCU grace period so we
1580 * don't leak it. We use call_rcu() here in order to be
1581 * able to call this function from atomic contexts. The
1582 * allocation of this memory will have reserved enough
1583 * space for struct listeners_rcu_head at the end.
1584 */
1585 old_rcu_head = (void *)(tbl->listeners +
1586 NLGRPLONGS(tbl->groups));
1587 old_rcu_head->ptr = old;
1588 call_rcu(&old_rcu_head->rcu_head, netlink_free_old_listeners);
1589 }
1590 tbl->groups = groups;
1591
1592 return 0;
1593 }
1594
1595 /**
1596 * netlink_change_ngroups - change number of multicast groups
1597 *
1598 * This changes the number of multicast groups that are available
1599 * on a certain netlink family. Note that it is not possible to
1600 * change the number of groups to below 32. Also note that it does
1601 * not implicitly call netlink_clear_multicast_users() when the
1602 * number of groups is reduced.
1603 *
1604 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1605 * @groups: The new number of groups.
1606 */
1607 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1608 {
1609 int err;
1610
1611 netlink_table_grab();
1612 err = __netlink_change_ngroups(sk, groups);
1613 netlink_table_ungrab();
1614
1615 return err;
1616 }
1617
1618 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1619 {
1620 struct sock *sk;
1621 struct hlist_node *node;
1622 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1623
1624 sk_for_each_bound(sk, node, &tbl->mc_list)
1625 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1626 }
1627
1628 /**
1629 * netlink_clear_multicast_users - kick off multicast listeners
1630 *
1631 * This function removes all listeners from the given group.
1632 * @ksk: The kernel netlink socket, as returned by
1633 * netlink_kernel_create().
1634 * @group: The multicast group to clear.
1635 */
1636 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1637 {
1638 netlink_table_grab();
1639 __netlink_clear_multicast_users(ksk, group);
1640 netlink_table_ungrab();
1641 }
1642
1643 void netlink_set_nonroot(int protocol, unsigned int flags)
1644 {
1645 if ((unsigned int)protocol < MAX_LINKS)
1646 nl_table[protocol].nl_nonroot = flags;
1647 }
1648 EXPORT_SYMBOL(netlink_set_nonroot);
1649
1650 static void netlink_destroy_callback(struct netlink_callback *cb)
1651 {
1652 kfree_skb(cb->skb);
1653 kfree(cb);
1654 }
1655
1656 /*
1657 * It looks a bit ugly.
1658 * It would be better to create kernel thread.
1659 */
1660
1661 static int netlink_dump(struct sock *sk)
1662 {
1663 struct netlink_sock *nlk = nlk_sk(sk);
1664 struct netlink_callback *cb;
1665 struct sk_buff *skb;
1666 struct nlmsghdr *nlh;
1667 int len, err = -ENOBUFS;
1668
1669 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1670 if (!skb)
1671 goto errout;
1672
1673 mutex_lock(nlk->cb_mutex);
1674
1675 cb = nlk->cb;
1676 if (cb == NULL) {
1677 err = -EINVAL;
1678 goto errout_skb;
1679 }
1680
1681 len = cb->dump(skb, cb);
1682
1683 if (len > 0) {
1684 mutex_unlock(nlk->cb_mutex);
1685
1686 if (sk_filter(sk, skb))
1687 kfree_skb(skb);
1688 else {
1689 skb_queue_tail(&sk->sk_receive_queue, skb);
1690 sk->sk_data_ready(sk, skb->len);
1691 }
1692 return 0;
1693 }
1694
1695 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1696 if (!nlh)
1697 goto errout_skb;
1698
1699 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1700
1701 if (sk_filter(sk, skb))
1702 kfree_skb(skb);
1703 else {
1704 skb_queue_tail(&sk->sk_receive_queue, skb);
1705 sk->sk_data_ready(sk, skb->len);
1706 }
1707
1708 if (cb->done)
1709 cb->done(cb);
1710 nlk->cb = NULL;
1711 mutex_unlock(nlk->cb_mutex);
1712
1713 netlink_destroy_callback(cb);
1714 return 0;
1715
1716 errout_skb:
1717 mutex_unlock(nlk->cb_mutex);
1718 kfree_skb(skb);
1719 errout:
1720 return err;
1721 }
1722
1723 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1724 const struct nlmsghdr *nlh,
1725 int (*dump)(struct sk_buff *skb,
1726 struct netlink_callback *),
1727 int (*done)(struct netlink_callback *))
1728 {
1729 struct netlink_callback *cb;
1730 struct sock *sk;
1731 struct netlink_sock *nlk;
1732
1733 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1734 if (cb == NULL)
1735 return -ENOBUFS;
1736
1737 cb->dump = dump;
1738 cb->done = done;
1739 cb->nlh = nlh;
1740 atomic_inc(&skb->users);
1741 cb->skb = skb;
1742
1743 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1744 if (sk == NULL) {
1745 netlink_destroy_callback(cb);
1746 return -ECONNREFUSED;
1747 }
1748 nlk = nlk_sk(sk);
1749 /* A dump is in progress... */
1750 mutex_lock(nlk->cb_mutex);
1751 if (nlk->cb) {
1752 mutex_unlock(nlk->cb_mutex);
1753 netlink_destroy_callback(cb);
1754 sock_put(sk);
1755 return -EBUSY;
1756 }
1757 nlk->cb = cb;
1758 mutex_unlock(nlk->cb_mutex);
1759
1760 netlink_dump(sk);
1761 sock_put(sk);
1762
1763 /* We successfully started a dump, by returning -EINTR we
1764 * signal not to send ACK even if it was requested.
1765 */
1766 return -EINTR;
1767 }
1768 EXPORT_SYMBOL(netlink_dump_start);
1769
1770 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1771 {
1772 struct sk_buff *skb;
1773 struct nlmsghdr *rep;
1774 struct nlmsgerr *errmsg;
1775 size_t payload = sizeof(*errmsg);
1776
1777 /* error messages get the original request appened */
1778 if (err)
1779 payload += nlmsg_len(nlh);
1780
1781 skb = nlmsg_new(payload, GFP_KERNEL);
1782 if (!skb) {
1783 struct sock *sk;
1784
1785 sk = netlink_lookup(sock_net(in_skb->sk),
1786 in_skb->sk->sk_protocol,
1787 NETLINK_CB(in_skb).pid);
1788 if (sk) {
1789 sk->sk_err = ENOBUFS;
1790 sk->sk_error_report(sk);
1791 sock_put(sk);
1792 }
1793 return;
1794 }
1795
1796 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1797 NLMSG_ERROR, payload, 0);
1798 errmsg = nlmsg_data(rep);
1799 errmsg->error = err;
1800 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1801 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1802 }
1803 EXPORT_SYMBOL(netlink_ack);
1804
1805 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1806 struct nlmsghdr *))
1807 {
1808 struct nlmsghdr *nlh;
1809 int err;
1810
1811 while (skb->len >= nlmsg_total_size(0)) {
1812 int msglen;
1813
1814 nlh = nlmsg_hdr(skb);
1815 err = 0;
1816
1817 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1818 return 0;
1819
1820 /* Only requests are handled by the kernel */
1821 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1822 goto ack;
1823
1824 /* Skip control messages */
1825 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1826 goto ack;
1827
1828 err = cb(skb, nlh);
1829 if (err == -EINTR)
1830 goto skip;
1831
1832 ack:
1833 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1834 netlink_ack(skb, nlh, err);
1835
1836 skip:
1837 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1838 if (msglen > skb->len)
1839 msglen = skb->len;
1840 skb_pull(skb, msglen);
1841 }
1842
1843 return 0;
1844 }
1845 EXPORT_SYMBOL(netlink_rcv_skb);
1846
1847 /**
1848 * nlmsg_notify - send a notification netlink message
1849 * @sk: netlink socket to use
1850 * @skb: notification message
1851 * @pid: destination netlink pid for reports or 0
1852 * @group: destination multicast group or 0
1853 * @report: 1 to report back, 0 to disable
1854 * @flags: allocation flags
1855 */
1856 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1857 unsigned int group, int report, gfp_t flags)
1858 {
1859 int err = 0;
1860
1861 if (group) {
1862 int exclude_pid = 0;
1863
1864 if (report) {
1865 atomic_inc(&skb->users);
1866 exclude_pid = pid;
1867 }
1868
1869 /* errors reported via destination sk->sk_err, but propagate
1870 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1871 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1872 }
1873
1874 if (report) {
1875 int err2;
1876
1877 err2 = nlmsg_unicast(sk, skb, pid);
1878 if (!err || err == -ESRCH)
1879 err = err2;
1880 }
1881
1882 return err;
1883 }
1884 EXPORT_SYMBOL(nlmsg_notify);
1885
1886 #ifdef CONFIG_PROC_FS
1887 struct nl_seq_iter {
1888 struct seq_net_private p;
1889 int link;
1890 int hash_idx;
1891 };
1892
1893 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1894 {
1895 struct nl_seq_iter *iter = seq->private;
1896 int i, j;
1897 struct sock *s;
1898 struct hlist_node *node;
1899 loff_t off = 0;
1900
1901 for (i = 0; i < MAX_LINKS; i++) {
1902 struct nl_pid_hash *hash = &nl_table[i].hash;
1903
1904 for (j = 0; j <= hash->mask; j++) {
1905 sk_for_each(s, node, &hash->table[j]) {
1906 if (sock_net(s) != seq_file_net(seq))
1907 continue;
1908 if (off == pos) {
1909 iter->link = i;
1910 iter->hash_idx = j;
1911 return s;
1912 }
1913 ++off;
1914 }
1915 }
1916 }
1917 return NULL;
1918 }
1919
1920 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1921 __acquires(nl_table_lock)
1922 {
1923 read_lock(&nl_table_lock);
1924 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1925 }
1926
1927 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1928 {
1929 struct sock *s;
1930 struct nl_seq_iter *iter;
1931 int i, j;
1932
1933 ++*pos;
1934
1935 if (v == SEQ_START_TOKEN)
1936 return netlink_seq_socket_idx(seq, 0);
1937
1938 iter = seq->private;
1939 s = v;
1940 do {
1941 s = sk_next(s);
1942 } while (s && sock_net(s) != seq_file_net(seq));
1943 if (s)
1944 return s;
1945
1946 i = iter->link;
1947 j = iter->hash_idx + 1;
1948
1949 do {
1950 struct nl_pid_hash *hash = &nl_table[i].hash;
1951
1952 for (; j <= hash->mask; j++) {
1953 s = sk_head(&hash->table[j]);
1954 while (s && sock_net(s) != seq_file_net(seq))
1955 s = sk_next(s);
1956 if (s) {
1957 iter->link = i;
1958 iter->hash_idx = j;
1959 return s;
1960 }
1961 }
1962
1963 j = 0;
1964 } while (++i < MAX_LINKS);
1965
1966 return NULL;
1967 }
1968
1969 static void netlink_seq_stop(struct seq_file *seq, void *v)
1970 __releases(nl_table_lock)
1971 {
1972 read_unlock(&nl_table_lock);
1973 }
1974
1975
1976 static int netlink_seq_show(struct seq_file *seq, void *v)
1977 {
1978 if (v == SEQ_START_TOKEN)
1979 seq_puts(seq,
1980 "sk Eth Pid Groups "
1981 "Rmem Wmem Dump Locks Drops\n");
1982 else {
1983 struct sock *s = v;
1984 struct netlink_sock *nlk = nlk_sk(s);
1985
1986 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %-8d %-8d\n",
1987 s,
1988 s->sk_protocol,
1989 nlk->pid,
1990 nlk->groups ? (u32)nlk->groups[0] : 0,
1991 sk_rmem_alloc_get(s),
1992 sk_wmem_alloc_get(s),
1993 nlk->cb,
1994 atomic_read(&s->sk_refcnt),
1995 atomic_read(&s->sk_drops)
1996 );
1997
1998 }
1999 return 0;
2000 }
2001
2002 static const struct seq_operations netlink_seq_ops = {
2003 .start = netlink_seq_start,
2004 .next = netlink_seq_next,
2005 .stop = netlink_seq_stop,
2006 .show = netlink_seq_show,
2007 };
2008
2009
2010 static int netlink_seq_open(struct inode *inode, struct file *file)
2011 {
2012 return seq_open_net(inode, file, &netlink_seq_ops,
2013 sizeof(struct nl_seq_iter));
2014 }
2015
2016 static const struct file_operations netlink_seq_fops = {
2017 .owner = THIS_MODULE,
2018 .open = netlink_seq_open,
2019 .read = seq_read,
2020 .llseek = seq_lseek,
2021 .release = seq_release_net,
2022 };
2023
2024 #endif
2025
2026 int netlink_register_notifier(struct notifier_block *nb)
2027 {
2028 return atomic_notifier_chain_register(&netlink_chain, nb);
2029 }
2030 EXPORT_SYMBOL(netlink_register_notifier);
2031
2032 int netlink_unregister_notifier(struct notifier_block *nb)
2033 {
2034 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2035 }
2036 EXPORT_SYMBOL(netlink_unregister_notifier);
2037
2038 static const struct proto_ops netlink_ops = {
2039 .family = PF_NETLINK,
2040 .owner = THIS_MODULE,
2041 .release = netlink_release,
2042 .bind = netlink_bind,
2043 .connect = netlink_connect,
2044 .socketpair = sock_no_socketpair,
2045 .accept = sock_no_accept,
2046 .getname = netlink_getname,
2047 .poll = datagram_poll,
2048 .ioctl = sock_no_ioctl,
2049 .listen = sock_no_listen,
2050 .shutdown = sock_no_shutdown,
2051 .setsockopt = netlink_setsockopt,
2052 .getsockopt = netlink_getsockopt,
2053 .sendmsg = netlink_sendmsg,
2054 .recvmsg = netlink_recvmsg,
2055 .mmap = sock_no_mmap,
2056 .sendpage = sock_no_sendpage,
2057 };
2058
2059 static const struct net_proto_family netlink_family_ops = {
2060 .family = PF_NETLINK,
2061 .create = netlink_create,
2062 .owner = THIS_MODULE, /* for consistency 8) */
2063 };
2064
2065 static int __net_init netlink_net_init(struct net *net)
2066 {
2067 #ifdef CONFIG_PROC_FS
2068 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2069 return -ENOMEM;
2070 #endif
2071 return 0;
2072 }
2073
2074 static void __net_exit netlink_net_exit(struct net *net)
2075 {
2076 #ifdef CONFIG_PROC_FS
2077 proc_net_remove(net, "netlink");
2078 #endif
2079 }
2080
2081 static struct pernet_operations __net_initdata netlink_net_ops = {
2082 .init = netlink_net_init,
2083 .exit = netlink_net_exit,
2084 };
2085
2086 static int __init netlink_proto_init(void)
2087 {
2088 struct sk_buff *dummy_skb;
2089 int i;
2090 unsigned long limit;
2091 unsigned int order;
2092 int err = proto_register(&netlink_proto, 0);
2093
2094 if (err != 0)
2095 goto out;
2096
2097 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2098
2099 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2100 if (!nl_table)
2101 goto panic;
2102
2103 if (totalram_pages >= (128 * 1024))
2104 limit = totalram_pages >> (21 - PAGE_SHIFT);
2105 else
2106 limit = totalram_pages >> (23 - PAGE_SHIFT);
2107
2108 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2109 limit = (1UL << order) / sizeof(struct hlist_head);
2110 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2111
2112 for (i = 0; i < MAX_LINKS; i++) {
2113 struct nl_pid_hash *hash = &nl_table[i].hash;
2114
2115 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
2116 if (!hash->table) {
2117 while (i-- > 0)
2118 nl_pid_hash_free(nl_table[i].hash.table,
2119 1 * sizeof(*hash->table));
2120 kfree(nl_table);
2121 goto panic;
2122 }
2123 hash->max_shift = order;
2124 hash->shift = 0;
2125 hash->mask = 0;
2126 hash->rehash_time = jiffies;
2127 }
2128
2129 sock_register(&netlink_family_ops);
2130 register_pernet_subsys(&netlink_net_ops);
2131 /* The netlink device handler may be needed early. */
2132 rtnetlink_init();
2133 out:
2134 return err;
2135 panic:
2136 panic("netlink_init: Cannot allocate nl_table\n");
2137 }
2138
2139 core_initcall(netlink_proto_init);
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree