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af_netlink: Add needed scm_destroy after scm_send.
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / netlink / af_netlink.c
blob7aeaa83193db96ecb0fb64f5d06db97168a1f9e6
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 = task_tgid_vnr(current);
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 (alen < sizeof(addr->sa_family))
687 return -EINVAL;
688
689 if (addr->sa_family == AF_UNSPEC) {
690 sk->sk_state = NETLINK_UNCONNECTED;
691 nlk->dst_pid = 0;
692 nlk->dst_group = 0;
693 return 0;
694 }
695 if (addr->sa_family != AF_NETLINK)
696 return -EINVAL;
697
698 /* Only superuser is allowed to send multicasts */
699 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
700 return -EPERM;
701
702 if (!nlk->pid)
703 err = netlink_autobind(sock);
704
705 if (err == 0) {
706 sk->sk_state = NETLINK_CONNECTED;
707 nlk->dst_pid = nladdr->nl_pid;
708 nlk->dst_group = ffs(nladdr->nl_groups);
709 }
710
711 return err;
712 }
713
714 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
715 int *addr_len, int peer)
716 {
717 struct sock *sk = sock->sk;
718 struct netlink_sock *nlk = nlk_sk(sk);
719 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
720
721 nladdr->nl_family = AF_NETLINK;
722 nladdr->nl_pad = 0;
723 *addr_len = sizeof(*nladdr);
724
725 if (peer) {
726 nladdr->nl_pid = nlk->dst_pid;
727 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
728 } else {
729 nladdr->nl_pid = nlk->pid;
730 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
731 }
732 return 0;
733 }
734
735 static void netlink_overrun(struct sock *sk)
736 {
737 struct netlink_sock *nlk = nlk_sk(sk);
738
739 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
740 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
741 sk->sk_err = ENOBUFS;
742 sk->sk_error_report(sk);
743 }
744 }
745 atomic_inc(&sk->sk_drops);
746 }
747
748 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
749 {
750 struct sock *sock;
751 struct netlink_sock *nlk;
752
753 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid);
754 if (!sock)
755 return ERR_PTR(-ECONNREFUSED);
756
757 /* Don't bother queuing skb if kernel socket has no input function */
758 nlk = nlk_sk(sock);
759 if (sock->sk_state == NETLINK_CONNECTED &&
760 nlk->dst_pid != nlk_sk(ssk)->pid) {
761 sock_put(sock);
762 return ERR_PTR(-ECONNREFUSED);
763 }
764 return sock;
765 }
766
767 struct sock *netlink_getsockbyfilp(struct file *filp)
768 {
769 struct inode *inode = filp->f_path.dentry->d_inode;
770 struct sock *sock;
771
772 if (!S_ISSOCK(inode->i_mode))
773 return ERR_PTR(-ENOTSOCK);
774
775 sock = SOCKET_I(inode)->sk;
776 if (sock->sk_family != AF_NETLINK)
777 return ERR_PTR(-EINVAL);
778
779 sock_hold(sock);
780 return sock;
781 }
782
783 /*
784 * Attach a skb to a netlink socket.
785 * The caller must hold a reference to the destination socket. On error, the
786 * reference is dropped. The skb is not send to the destination, just all
787 * all error checks are performed and memory in the queue is reserved.
788 * Return values:
789 * < 0: error. skb freed, reference to sock dropped.
790 * 0: continue
791 * 1: repeat lookup - reference dropped while waiting for socket memory.
792 */
793 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
794 long *timeo, struct sock *ssk)
795 {
796 struct netlink_sock *nlk;
797
798 nlk = nlk_sk(sk);
799
800 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
801 test_bit(0, &nlk->state)) {
802 DECLARE_WAITQUEUE(wait, current);
803 if (!*timeo) {
804 if (!ssk || netlink_is_kernel(ssk))
805 netlink_overrun(sk);
806 sock_put(sk);
807 kfree_skb(skb);
808 return -EAGAIN;
809 }
810
811 __set_current_state(TASK_INTERRUPTIBLE);
812 add_wait_queue(&nlk->wait, &wait);
813
814 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
815 test_bit(0, &nlk->state)) &&
816 !sock_flag(sk, SOCK_DEAD))
817 *timeo = schedule_timeout(*timeo);
818
819 __set_current_state(TASK_RUNNING);
820 remove_wait_queue(&nlk->wait, &wait);
821 sock_put(sk);
822
823 if (signal_pending(current)) {
824 kfree_skb(skb);
825 return sock_intr_errno(*timeo);
826 }
827 return 1;
828 }
829 skb_set_owner_r(skb, sk);
830 return 0;
831 }
832
833 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
834 {
835 int len = skb->len;
836
837 skb_queue_tail(&sk->sk_receive_queue, skb);
838 sk->sk_data_ready(sk, len);
839 sock_put(sk);
840 return len;
841 }
842
843 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
844 {
845 kfree_skb(skb);
846 sock_put(sk);
847 }
848
849 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
850 gfp_t allocation)
851 {
852 int delta;
853
854 skb_orphan(skb);
855
856 delta = skb->end - skb->tail;
857 if (delta * 2 < skb->truesize)
858 return skb;
859
860 if (skb_shared(skb)) {
861 struct sk_buff *nskb = skb_clone(skb, allocation);
862 if (!nskb)
863 return skb;
864 kfree_skb(skb);
865 skb = nskb;
866 }
867
868 if (!pskb_expand_head(skb, 0, -delta, allocation))
869 skb->truesize -= delta;
870
871 return skb;
872 }
873
874 static inline void netlink_rcv_wake(struct sock *sk)
875 {
876 struct netlink_sock *nlk = nlk_sk(sk);
877
878 if (skb_queue_empty(&sk->sk_receive_queue))
879 clear_bit(0, &nlk->state);
880 if (!test_bit(0, &nlk->state))
881 wake_up_interruptible(&nlk->wait);
882 }
883
884 static inline int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb)
885 {
886 int ret;
887 struct netlink_sock *nlk = nlk_sk(sk);
888
889 ret = -ECONNREFUSED;
890 if (nlk->netlink_rcv != NULL) {
891 ret = skb->len;
892 skb_set_owner_r(skb, sk);
893 nlk->netlink_rcv(skb);
894 }
895 kfree_skb(skb);
896 sock_put(sk);
897 return ret;
898 }
899
900 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
901 u32 pid, int nonblock)
902 {
903 struct sock *sk;
904 int err;
905 long timeo;
906
907 skb = netlink_trim(skb, gfp_any());
908
909 timeo = sock_sndtimeo(ssk, nonblock);
910 retry:
911 sk = netlink_getsockbypid(ssk, pid);
912 if (IS_ERR(sk)) {
913 kfree_skb(skb);
914 return PTR_ERR(sk);
915 }
916 if (netlink_is_kernel(sk))
917 return netlink_unicast_kernel(sk, skb);
918
919 if (sk_filter(sk, skb)) {
920 err = skb->len;
921 kfree_skb(skb);
922 sock_put(sk);
923 return err;
924 }
925
926 err = netlink_attachskb(sk, skb, &timeo, ssk);
927 if (err == 1)
928 goto retry;
929 if (err)
930 return err;
931
932 return netlink_sendskb(sk, skb);
933 }
934 EXPORT_SYMBOL(netlink_unicast);
935
936 int netlink_has_listeners(struct sock *sk, unsigned int group)
937 {
938 int res = 0;
939 unsigned long *listeners;
940
941 BUG_ON(!netlink_is_kernel(sk));
942
943 rcu_read_lock();
944 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
945
946 if (group - 1 < nl_table[sk->sk_protocol].groups)
947 res = test_bit(group - 1, listeners);
948
949 rcu_read_unlock();
950
951 return res;
952 }
953 EXPORT_SYMBOL_GPL(netlink_has_listeners);
954
955 static inline int netlink_broadcast_deliver(struct sock *sk,
956 struct sk_buff *skb)
957 {
958 struct netlink_sock *nlk = nlk_sk(sk);
959
960 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
961 !test_bit(0, &nlk->state)) {
962 skb_set_owner_r(skb, sk);
963 skb_queue_tail(&sk->sk_receive_queue, skb);
964 sk->sk_data_ready(sk, skb->len);
965 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
966 }
967 return -1;
968 }
969
970 struct netlink_broadcast_data {
971 struct sock *exclude_sk;
972 struct net *net;
973 u32 pid;
974 u32 group;
975 int failure;
976 int delivery_failure;
977 int congested;
978 int delivered;
979 gfp_t allocation;
980 struct sk_buff *skb, *skb2;
981 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
982 void *tx_data;
983 };
984
985 static inline int do_one_broadcast(struct sock *sk,
986 struct netlink_broadcast_data *p)
987 {
988 struct netlink_sock *nlk = nlk_sk(sk);
989 int val;
990
991 if (p->exclude_sk == sk)
992 goto out;
993
994 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
995 !test_bit(p->group - 1, nlk->groups))
996 goto out;
997
998 if (!net_eq(sock_net(sk), p->net))
999 goto out;
1000
1001 if (p->failure) {
1002 netlink_overrun(sk);
1003 goto out;
1004 }
1005
1006 sock_hold(sk);
1007 if (p->skb2 == NULL) {
1008 if (skb_shared(p->skb)) {
1009 p->skb2 = skb_clone(p->skb, p->allocation);
1010 } else {
1011 p->skb2 = skb_get(p->skb);
1012 /*
1013 * skb ownership may have been set when
1014 * delivered to a previous socket.
1015 */
1016 skb_orphan(p->skb2);
1017 }
1018 }
1019 if (p->skb2 == NULL) {
1020 netlink_overrun(sk);
1021 /* Clone failed. Notify ALL listeners. */
1022 p->failure = 1;
1023 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1024 p->delivery_failure = 1;
1025 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1026 kfree_skb(p->skb2);
1027 p->skb2 = NULL;
1028 } else if (sk_filter(sk, p->skb2)) {
1029 kfree_skb(p->skb2);
1030 p->skb2 = NULL;
1031 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1032 netlink_overrun(sk);
1033 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1034 p->delivery_failure = 1;
1035 } else {
1036 p->congested |= val;
1037 p->delivered = 1;
1038 p->skb2 = NULL;
1039 }
1040 sock_put(sk);
1041
1042 out:
1043 return 0;
1044 }
1045
1046 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 pid,
1047 u32 group, gfp_t allocation,
1048 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1049 void *filter_data)
1050 {
1051 struct net *net = sock_net(ssk);
1052 struct netlink_broadcast_data info;
1053 struct hlist_node *node;
1054 struct sock *sk;
1055
1056 skb = netlink_trim(skb, allocation);
1057
1058 info.exclude_sk = ssk;
1059 info.net = net;
1060 info.pid = pid;
1061 info.group = group;
1062 info.failure = 0;
1063 info.delivery_failure = 0;
1064 info.congested = 0;
1065 info.delivered = 0;
1066 info.allocation = allocation;
1067 info.skb = skb;
1068 info.skb2 = NULL;
1069 info.tx_filter = filter;
1070 info.tx_data = filter_data;
1071
1072 /* While we sleep in clone, do not allow to change socket list */
1073
1074 netlink_lock_table();
1075
1076 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1077 do_one_broadcast(sk, &info);
1078
1079 kfree_skb(skb);
1080
1081 netlink_unlock_table();
1082
1083 kfree_skb(info.skb2);
1084
1085 if (info.delivery_failure)
1086 return -ENOBUFS;
1087
1088 if (info.delivered) {
1089 if (info.congested && (allocation & __GFP_WAIT))
1090 yield();
1091 return 0;
1092 }
1093 return -ESRCH;
1094 }
1095 EXPORT_SYMBOL(netlink_broadcast_filtered);
1096
1097 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
1098 u32 group, gfp_t allocation)
1099 {
1100 return netlink_broadcast_filtered(ssk, skb, pid, group, allocation,
1101 NULL, NULL);
1102 }
1103 EXPORT_SYMBOL(netlink_broadcast);
1104
1105 struct netlink_set_err_data {
1106 struct sock *exclude_sk;
1107 u32 pid;
1108 u32 group;
1109 int code;
1110 };
1111
1112 static inline int do_one_set_err(struct sock *sk,
1113 struct netlink_set_err_data *p)
1114 {
1115 struct netlink_sock *nlk = nlk_sk(sk);
1116 int ret = 0;
1117
1118 if (sk == p->exclude_sk)
1119 goto out;
1120
1121 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1122 goto out;
1123
1124 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1125 !test_bit(p->group - 1, nlk->groups))
1126 goto out;
1127
1128 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
1129 ret = 1;
1130 goto out;
1131 }
1132
1133 sk->sk_err = p->code;
1134 sk->sk_error_report(sk);
1135 out:
1136 return ret;
1137 }
1138
1139 /**
1140 * netlink_set_err - report error to broadcast listeners
1141 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1142 * @pid: the PID of a process that we want to skip (if any)
1143 * @groups: the broadcast group that will notice the error
1144 * @code: error code, must be negative (as usual in kernelspace)
1145 *
1146 * This function returns the number of broadcast listeners that have set the
1147 * NETLINK_RECV_NO_ENOBUFS socket option.
1148 */
1149 int netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1150 {
1151 struct netlink_set_err_data info;
1152 struct hlist_node *node;
1153 struct sock *sk;
1154 int ret = 0;
1155
1156 info.exclude_sk = ssk;
1157 info.pid = pid;
1158 info.group = group;
1159 /* sk->sk_err wants a positive error value */
1160 info.code = -code;
1161
1162 read_lock(&nl_table_lock);
1163
1164 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1165 ret += do_one_set_err(sk, &info);
1166
1167 read_unlock(&nl_table_lock);
1168 return ret;
1169 }
1170 EXPORT_SYMBOL(netlink_set_err);
1171
1172 /* must be called with netlink table grabbed */
1173 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1174 unsigned int group,
1175 int is_new)
1176 {
1177 int old, new = !!is_new, subscriptions;
1178
1179 old = test_bit(group - 1, nlk->groups);
1180 subscriptions = nlk->subscriptions - old + new;
1181 if (new)
1182 __set_bit(group - 1, nlk->groups);
1183 else
1184 __clear_bit(group - 1, nlk->groups);
1185 netlink_update_subscriptions(&nlk->sk, subscriptions);
1186 netlink_update_listeners(&nlk->sk);
1187 }
1188
1189 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1190 char __user *optval, unsigned int optlen)
1191 {
1192 struct sock *sk = sock->sk;
1193 struct netlink_sock *nlk = nlk_sk(sk);
1194 unsigned int val = 0;
1195 int err;
1196
1197 if (level != SOL_NETLINK)
1198 return -ENOPROTOOPT;
1199
1200 if (optlen >= sizeof(int) &&
1201 get_user(val, (unsigned int __user *)optval))
1202 return -EFAULT;
1203
1204 switch (optname) {
1205 case NETLINK_PKTINFO:
1206 if (val)
1207 nlk->flags |= NETLINK_RECV_PKTINFO;
1208 else
1209 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1210 err = 0;
1211 break;
1212 case NETLINK_ADD_MEMBERSHIP:
1213 case NETLINK_DROP_MEMBERSHIP: {
1214 if (!netlink_capable(sock, NL_NONROOT_RECV))
1215 return -EPERM;
1216 err = netlink_realloc_groups(sk);
1217 if (err)
1218 return err;
1219 if (!val || val - 1 >= nlk->ngroups)
1220 return -EINVAL;
1221 netlink_table_grab();
1222 netlink_update_socket_mc(nlk, val,
1223 optname == NETLINK_ADD_MEMBERSHIP);
1224 netlink_table_ungrab();
1225 err = 0;
1226 break;
1227 }
1228 case NETLINK_BROADCAST_ERROR:
1229 if (val)
1230 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1231 else
1232 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1233 err = 0;
1234 break;
1235 case NETLINK_NO_ENOBUFS:
1236 if (val) {
1237 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1238 clear_bit(0, &nlk->state);
1239 wake_up_interruptible(&nlk->wait);
1240 } else
1241 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1242 err = 0;
1243 break;
1244 default:
1245 err = -ENOPROTOOPT;
1246 }
1247 return err;
1248 }
1249
1250 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1251 char __user *optval, int __user *optlen)
1252 {
1253 struct sock *sk = sock->sk;
1254 struct netlink_sock *nlk = nlk_sk(sk);
1255 int len, val, err;
1256
1257 if (level != SOL_NETLINK)
1258 return -ENOPROTOOPT;
1259
1260 if (get_user(len, optlen))
1261 return -EFAULT;
1262 if (len < 0)
1263 return -EINVAL;
1264
1265 switch (optname) {
1266 case NETLINK_PKTINFO:
1267 if (len < sizeof(int))
1268 return -EINVAL;
1269 len = sizeof(int);
1270 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1271 if (put_user(len, optlen) ||
1272 put_user(val, optval))
1273 return -EFAULT;
1274 err = 0;
1275 break;
1276 case NETLINK_BROADCAST_ERROR:
1277 if (len < sizeof(int))
1278 return -EINVAL;
1279 len = sizeof(int);
1280 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1281 if (put_user(len, optlen) ||
1282 put_user(val, optval))
1283 return -EFAULT;
1284 err = 0;
1285 break;
1286 case NETLINK_NO_ENOBUFS:
1287 if (len < sizeof(int))
1288 return -EINVAL;
1289 len = sizeof(int);
1290 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1291 if (put_user(len, optlen) ||
1292 put_user(val, optval))
1293 return -EFAULT;
1294 err = 0;
1295 break;
1296 default:
1297 err = -ENOPROTOOPT;
1298 }
1299 return err;
1300 }
1301
1302 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1303 {
1304 struct nl_pktinfo info;
1305
1306 info.group = NETLINK_CB(skb).dst_group;
1307 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1308 }
1309
1310 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1311 struct msghdr *msg, size_t len)
1312 {
1313 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1314 struct sock *sk = sock->sk;
1315 struct netlink_sock *nlk = nlk_sk(sk);
1316 struct sockaddr_nl *addr = msg->msg_name;
1317 u32 dst_pid;
1318 u32 dst_group;
1319 struct sk_buff *skb;
1320 int err;
1321 struct scm_cookie scm;
1322
1323 if (msg->msg_flags&MSG_OOB)
1324 return -EOPNOTSUPP;
1325
1326 if (NULL == siocb->scm) {
1327 siocb->scm = &scm;
1328 memset(&scm, 0, sizeof(scm));
1329 }
1330 err = scm_send(sock, msg, siocb->scm);
1331 if (err < 0)
1332 return err;
1333
1334 if (msg->msg_namelen) {
1335 err = -EINVAL;
1336 if (addr->nl_family != AF_NETLINK)
1337 goto out;
1338 dst_pid = addr->nl_pid;
1339 dst_group = ffs(addr->nl_groups);
1340 err = -EPERM;
1341 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1342 goto out;
1343 } else {
1344 dst_pid = nlk->dst_pid;
1345 dst_group = nlk->dst_group;
1346 }
1347
1348 if (!nlk->pid) {
1349 err = netlink_autobind(sock);
1350 if (err)
1351 goto out;
1352 }
1353
1354 err = -EMSGSIZE;
1355 if (len > sk->sk_sndbuf - 32)
1356 goto out;
1357 err = -ENOBUFS;
1358 skb = alloc_skb(len, GFP_KERNEL);
1359 if (skb == NULL)
1360 goto out;
1361
1362 NETLINK_CB(skb).pid = nlk->pid;
1363 NETLINK_CB(skb).dst_group = dst_group;
1364 NETLINK_CB(skb).loginuid = audit_get_loginuid(current);
1365 NETLINK_CB(skb).sessionid = audit_get_sessionid(current);
1366 security_task_getsecid(current, &(NETLINK_CB(skb).sid));
1367 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1368
1369 /* What can I do? Netlink is asynchronous, so that
1370 we will have to save current capabilities to
1371 check them, when this message will be delivered
1372 to corresponding kernel module. --ANK (980802)
1373 */
1374
1375 err = -EFAULT;
1376 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1377 kfree_skb(skb);
1378 goto out;
1379 }
1380
1381 err = security_netlink_send(sk, skb);
1382 if (err) {
1383 kfree_skb(skb);
1384 goto out;
1385 }
1386
1387 if (dst_group) {
1388 atomic_inc(&skb->users);
1389 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1390 }
1391 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1392
1393 out:
1394 scm_destroy(siocb->scm);
1395 return err;
1396 }
1397
1398 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1399 struct msghdr *msg, size_t len,
1400 int flags)
1401 {
1402 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1403 struct scm_cookie scm;
1404 struct sock *sk = sock->sk;
1405 struct netlink_sock *nlk = nlk_sk(sk);
1406 int noblock = flags&MSG_DONTWAIT;
1407 size_t copied;
1408 struct sk_buff *skb, *frag __maybe_unused = NULL;
1409 int err;
1410
1411 if (flags&MSG_OOB)
1412 return -EOPNOTSUPP;
1413
1414 copied = 0;
1415
1416 skb = skb_recv_datagram(sk, flags, noblock, &err);
1417 if (skb == NULL)
1418 goto out;
1419
1420 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1421 if (unlikely(skb_shinfo(skb)->frag_list)) {
1422 bool need_compat = !!(flags & MSG_CMSG_COMPAT);
1423
1424 /*
1425 * If this skb has a frag_list, then here that means that
1426 * we will have to use the frag_list skb for compat tasks
1427 * and the regular skb for non-compat tasks.
1428 *
1429 * The skb might (and likely will) be cloned, so we can't
1430 * just reset frag_list and go on with things -- we need to
1431 * keep that. For the compat case that's easy -- simply get
1432 * a reference to the compat skb and free the regular one
1433 * including the frag. For the non-compat case, we need to
1434 * avoid sending the frag to the user -- so assign NULL but
1435 * restore it below before freeing the skb.
1436 */
1437 if (need_compat) {
1438 struct sk_buff *compskb = skb_shinfo(skb)->frag_list;
1439 skb_get(compskb);
1440 kfree_skb(skb);
1441 skb = compskb;
1442 } else {
1443 frag = skb_shinfo(skb)->frag_list;
1444 skb_shinfo(skb)->frag_list = NULL;
1445 }
1446 }
1447 #endif
1448
1449 msg->msg_namelen = 0;
1450
1451 copied = skb->len;
1452 if (len < copied) {
1453 msg->msg_flags |= MSG_TRUNC;
1454 copied = len;
1455 }
1456
1457 skb_reset_transport_header(skb);
1458 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1459
1460 if (msg->msg_name) {
1461 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1462 addr->nl_family = AF_NETLINK;
1463 addr->nl_pad = 0;
1464 addr->nl_pid = NETLINK_CB(skb).pid;
1465 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1466 msg->msg_namelen = sizeof(*addr);
1467 }
1468
1469 if (nlk->flags & NETLINK_RECV_PKTINFO)
1470 netlink_cmsg_recv_pktinfo(msg, skb);
1471
1472 if (NULL == siocb->scm) {
1473 memset(&scm, 0, sizeof(scm));
1474 siocb->scm = &scm;
1475 }
1476 siocb->scm->creds = *NETLINK_CREDS(skb);
1477 if (flags & MSG_TRUNC)
1478 copied = skb->len;
1479
1480 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1481 skb_shinfo(skb)->frag_list = frag;
1482 #endif
1483
1484 skb_free_datagram(sk, skb);
1485
1486 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1487 netlink_dump(sk);
1488
1489 scm_recv(sock, msg, siocb->scm, flags);
1490 out:
1491 netlink_rcv_wake(sk);
1492 return err ? : copied;
1493 }
1494
1495 static void netlink_data_ready(struct sock *sk, int len)
1496 {
1497 BUG();
1498 }
1499
1500 /*
1501 * We export these functions to other modules. They provide a
1502 * complete set of kernel non-blocking support for message
1503 * queueing.
1504 */
1505
1506 struct sock *
1507 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1508 void (*input)(struct sk_buff *skb),
1509 struct mutex *cb_mutex, struct module *module)
1510 {
1511 struct socket *sock;
1512 struct sock *sk;
1513 struct netlink_sock *nlk;
1514 unsigned long *listeners = NULL;
1515
1516 BUG_ON(!nl_table);
1517
1518 if (unit < 0 || unit >= MAX_LINKS)
1519 return NULL;
1520
1521 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1522 return NULL;
1523
1524 /*
1525 * We have to just have a reference on the net from sk, but don't
1526 * get_net it. Besides, we cannot get and then put the net here.
1527 * So we create one inside init_net and the move it to net.
1528 */
1529
1530 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1531 goto out_sock_release_nosk;
1532
1533 sk = sock->sk;
1534 sk_change_net(sk, net);
1535
1536 if (groups < 32)
1537 groups = 32;
1538
1539 listeners = kzalloc(NLGRPSZ(groups) + sizeof(struct listeners_rcu_head),
1540 GFP_KERNEL);
1541 if (!listeners)
1542 goto out_sock_release;
1543
1544 sk->sk_data_ready = netlink_data_ready;
1545 if (input)
1546 nlk_sk(sk)->netlink_rcv = input;
1547
1548 if (netlink_insert(sk, net, 0))
1549 goto out_sock_release;
1550
1551 nlk = nlk_sk(sk);
1552 nlk->flags |= NETLINK_KERNEL_SOCKET;
1553
1554 netlink_table_grab();
1555 if (!nl_table[unit].registered) {
1556 nl_table[unit].groups = groups;
1557 nl_table[unit].listeners = listeners;
1558 nl_table[unit].cb_mutex = cb_mutex;
1559 nl_table[unit].module = module;
1560 nl_table[unit].registered = 1;
1561 } else {
1562 kfree(listeners);
1563 nl_table[unit].registered++;
1564 }
1565 netlink_table_ungrab();
1566 return sk;
1567
1568 out_sock_release:
1569 kfree(listeners);
1570 netlink_kernel_release(sk);
1571 return NULL;
1572
1573 out_sock_release_nosk:
1574 sock_release(sock);
1575 return NULL;
1576 }
1577 EXPORT_SYMBOL(netlink_kernel_create);
1578
1579
1580 void
1581 netlink_kernel_release(struct sock *sk)
1582 {
1583 sk_release_kernel(sk);
1584 }
1585 EXPORT_SYMBOL(netlink_kernel_release);
1586
1587
1588 static void netlink_free_old_listeners(struct rcu_head *rcu_head)
1589 {
1590 struct listeners_rcu_head *lrh;
1591
1592 lrh = container_of(rcu_head, struct listeners_rcu_head, rcu_head);
1593 kfree(lrh->ptr);
1594 }
1595
1596 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1597 {
1598 unsigned long *listeners, *old = NULL;
1599 struct listeners_rcu_head *old_rcu_head;
1600 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1601
1602 if (groups < 32)
1603 groups = 32;
1604
1605 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1606 listeners = kzalloc(NLGRPSZ(groups) +
1607 sizeof(struct listeners_rcu_head),
1608 GFP_ATOMIC);
1609 if (!listeners)
1610 return -ENOMEM;
1611 old = tbl->listeners;
1612 memcpy(listeners, old, NLGRPSZ(tbl->groups));
1613 rcu_assign_pointer(tbl->listeners, listeners);
1614 /*
1615 * Free the old memory after an RCU grace period so we
1616 * don't leak it. We use call_rcu() here in order to be
1617 * able to call this function from atomic contexts. The
1618 * allocation of this memory will have reserved enough
1619 * space for struct listeners_rcu_head at the end.
1620 */
1621 old_rcu_head = (void *)(tbl->listeners +
1622 NLGRPLONGS(tbl->groups));
1623 old_rcu_head->ptr = old;
1624 call_rcu(&old_rcu_head->rcu_head, netlink_free_old_listeners);
1625 }
1626 tbl->groups = groups;
1627
1628 return 0;
1629 }
1630
1631 /**
1632 * netlink_change_ngroups - change number of multicast groups
1633 *
1634 * This changes the number of multicast groups that are available
1635 * on a certain netlink family. Note that it is not possible to
1636 * change the number of groups to below 32. Also note that it does
1637 * not implicitly call netlink_clear_multicast_users() when the
1638 * number of groups is reduced.
1639 *
1640 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1641 * @groups: The new number of groups.
1642 */
1643 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1644 {
1645 int err;
1646
1647 netlink_table_grab();
1648 err = __netlink_change_ngroups(sk, groups);
1649 netlink_table_ungrab();
1650
1651 return err;
1652 }
1653
1654 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1655 {
1656 struct sock *sk;
1657 struct hlist_node *node;
1658 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1659
1660 sk_for_each_bound(sk, node, &tbl->mc_list)
1661 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1662 }
1663
1664 /**
1665 * netlink_clear_multicast_users - kick off multicast listeners
1666 *
1667 * This function removes all listeners from the given group.
1668 * @ksk: The kernel netlink socket, as returned by
1669 * netlink_kernel_create().
1670 * @group: The multicast group to clear.
1671 */
1672 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1673 {
1674 netlink_table_grab();
1675 __netlink_clear_multicast_users(ksk, group);
1676 netlink_table_ungrab();
1677 }
1678
1679 void netlink_set_nonroot(int protocol, unsigned int flags)
1680 {
1681 if ((unsigned int)protocol < MAX_LINKS)
1682 nl_table[protocol].nl_nonroot = flags;
1683 }
1684 EXPORT_SYMBOL(netlink_set_nonroot);
1685
1686 static void netlink_destroy_callback(struct netlink_callback *cb)
1687 {
1688 kfree_skb(cb->skb);
1689 kfree(cb);
1690 }
1691
1692 /*
1693 * It looks a bit ugly.
1694 * It would be better to create kernel thread.
1695 */
1696
1697 static int netlink_dump(struct sock *sk)
1698 {
1699 struct netlink_sock *nlk = nlk_sk(sk);
1700 struct netlink_callback *cb;
1701 struct sk_buff *skb;
1702 struct nlmsghdr *nlh;
1703 int len, err = -ENOBUFS;
1704
1705 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1706 if (!skb)
1707 goto errout;
1708
1709 mutex_lock(nlk->cb_mutex);
1710
1711 cb = nlk->cb;
1712 if (cb == NULL) {
1713 err = -EINVAL;
1714 goto errout_skb;
1715 }
1716
1717 len = cb->dump(skb, cb);
1718
1719 if (len > 0) {
1720 mutex_unlock(nlk->cb_mutex);
1721
1722 if (sk_filter(sk, skb))
1723 kfree_skb(skb);
1724 else {
1725 skb_queue_tail(&sk->sk_receive_queue, skb);
1726 sk->sk_data_ready(sk, skb->len);
1727 }
1728 return 0;
1729 }
1730
1731 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1732 if (!nlh)
1733 goto errout_skb;
1734
1735 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1736
1737 if (sk_filter(sk, skb))
1738 kfree_skb(skb);
1739 else {
1740 skb_queue_tail(&sk->sk_receive_queue, skb);
1741 sk->sk_data_ready(sk, skb->len);
1742 }
1743
1744 if (cb->done)
1745 cb->done(cb);
1746 nlk->cb = NULL;
1747 mutex_unlock(nlk->cb_mutex);
1748
1749 netlink_destroy_callback(cb);
1750 return 0;
1751
1752 errout_skb:
1753 mutex_unlock(nlk->cb_mutex);
1754 kfree_skb(skb);
1755 errout:
1756 return err;
1757 }
1758
1759 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1760 const struct nlmsghdr *nlh,
1761 int (*dump)(struct sk_buff *skb,
1762 struct netlink_callback *),
1763 int (*done)(struct netlink_callback *))
1764 {
1765 struct netlink_callback *cb;
1766 struct sock *sk;
1767 struct netlink_sock *nlk;
1768
1769 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1770 if (cb == NULL)
1771 return -ENOBUFS;
1772
1773 cb->dump = dump;
1774 cb->done = done;
1775 cb->nlh = nlh;
1776 atomic_inc(&skb->users);
1777 cb->skb = skb;
1778
1779 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1780 if (sk == NULL) {
1781 netlink_destroy_callback(cb);
1782 return -ECONNREFUSED;
1783 }
1784 nlk = nlk_sk(sk);
1785 /* A dump is in progress... */
1786 mutex_lock(nlk->cb_mutex);
1787 if (nlk->cb) {
1788 mutex_unlock(nlk->cb_mutex);
1789 netlink_destroy_callback(cb);
1790 sock_put(sk);
1791 return -EBUSY;
1792 }
1793 nlk->cb = cb;
1794 mutex_unlock(nlk->cb_mutex);
1795
1796 netlink_dump(sk);
1797 sock_put(sk);
1798
1799 /* We successfully started a dump, by returning -EINTR we
1800 * signal not to send ACK even if it was requested.
1801 */
1802 return -EINTR;
1803 }
1804 EXPORT_SYMBOL(netlink_dump_start);
1805
1806 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1807 {
1808 struct sk_buff *skb;
1809 struct nlmsghdr *rep;
1810 struct nlmsgerr *errmsg;
1811 size_t payload = sizeof(*errmsg);
1812
1813 /* error messages get the original request appened */
1814 if (err)
1815 payload += nlmsg_len(nlh);
1816
1817 skb = nlmsg_new(payload, GFP_KERNEL);
1818 if (!skb) {
1819 struct sock *sk;
1820
1821 sk = netlink_lookup(sock_net(in_skb->sk),
1822 in_skb->sk->sk_protocol,
1823 NETLINK_CB(in_skb).pid);
1824 if (sk) {
1825 sk->sk_err = ENOBUFS;
1826 sk->sk_error_report(sk);
1827 sock_put(sk);
1828 }
1829 return;
1830 }
1831
1832 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1833 NLMSG_ERROR, payload, 0);
1834 errmsg = nlmsg_data(rep);
1835 errmsg->error = err;
1836 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1837 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1838 }
1839 EXPORT_SYMBOL(netlink_ack);
1840
1841 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1842 struct nlmsghdr *))
1843 {
1844 struct nlmsghdr *nlh;
1845 int err;
1846
1847 while (skb->len >= nlmsg_total_size(0)) {
1848 int msglen;
1849
1850 nlh = nlmsg_hdr(skb);
1851 err = 0;
1852
1853 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1854 return 0;
1855
1856 /* Only requests are handled by the kernel */
1857 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1858 goto ack;
1859
1860 /* Skip control messages */
1861 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1862 goto ack;
1863
1864 err = cb(skb, nlh);
1865 if (err == -EINTR)
1866 goto skip;
1867
1868 ack:
1869 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1870 netlink_ack(skb, nlh, err);
1871
1872 skip:
1873 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1874 if (msglen > skb->len)
1875 msglen = skb->len;
1876 skb_pull(skb, msglen);
1877 }
1878
1879 return 0;
1880 }
1881 EXPORT_SYMBOL(netlink_rcv_skb);
1882
1883 /**
1884 * nlmsg_notify - send a notification netlink message
1885 * @sk: netlink socket to use
1886 * @skb: notification message
1887 * @pid: destination netlink pid for reports or 0
1888 * @group: destination multicast group or 0
1889 * @report: 1 to report back, 0 to disable
1890 * @flags: allocation flags
1891 */
1892 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1893 unsigned int group, int report, gfp_t flags)
1894 {
1895 int err = 0;
1896
1897 if (group) {
1898 int exclude_pid = 0;
1899
1900 if (report) {
1901 atomic_inc(&skb->users);
1902 exclude_pid = pid;
1903 }
1904
1905 /* errors reported via destination sk->sk_err, but propagate
1906 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1907 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1908 }
1909
1910 if (report) {
1911 int err2;
1912
1913 err2 = nlmsg_unicast(sk, skb, pid);
1914 if (!err || err == -ESRCH)
1915 err = err2;
1916 }
1917
1918 return err;
1919 }
1920 EXPORT_SYMBOL(nlmsg_notify);
1921
1922 #ifdef CONFIG_PROC_FS
1923 struct nl_seq_iter {
1924 struct seq_net_private p;
1925 int link;
1926 int hash_idx;
1927 };
1928
1929 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1930 {
1931 struct nl_seq_iter *iter = seq->private;
1932 int i, j;
1933 struct sock *s;
1934 struct hlist_node *node;
1935 loff_t off = 0;
1936
1937 for (i = 0; i < MAX_LINKS; i++) {
1938 struct nl_pid_hash *hash = &nl_table[i].hash;
1939
1940 for (j = 0; j <= hash->mask; j++) {
1941 sk_for_each(s, node, &hash->table[j]) {
1942 if (sock_net(s) != seq_file_net(seq))
1943 continue;
1944 if (off == pos) {
1945 iter->link = i;
1946 iter->hash_idx = j;
1947 return s;
1948 }
1949 ++off;
1950 }
1951 }
1952 }
1953 return NULL;
1954 }
1955
1956 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1957 __acquires(nl_table_lock)
1958 {
1959 read_lock(&nl_table_lock);
1960 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1961 }
1962
1963 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1964 {
1965 struct sock *s;
1966 struct nl_seq_iter *iter;
1967 int i, j;
1968
1969 ++*pos;
1970
1971 if (v == SEQ_START_TOKEN)
1972 return netlink_seq_socket_idx(seq, 0);
1973
1974 iter = seq->private;
1975 s = v;
1976 do {
1977 s = sk_next(s);
1978 } while (s && sock_net(s) != seq_file_net(seq));
1979 if (s)
1980 return s;
1981
1982 i = iter->link;
1983 j = iter->hash_idx + 1;
1984
1985 do {
1986 struct nl_pid_hash *hash = &nl_table[i].hash;
1987
1988 for (; j <= hash->mask; j++) {
1989 s = sk_head(&hash->table[j]);
1990 while (s && sock_net(s) != seq_file_net(seq))
1991 s = sk_next(s);
1992 if (s) {
1993 iter->link = i;
1994 iter->hash_idx = j;
1995 return s;
1996 }
1997 }
1998
1999 j = 0;
2000 } while (++i < MAX_LINKS);
2001
2002 return NULL;
2003 }
2004
2005 static void netlink_seq_stop(struct seq_file *seq, void *v)
2006 __releases(nl_table_lock)
2007 {
2008 read_unlock(&nl_table_lock);
2009 }
2010
2011
2012 static int netlink_seq_show(struct seq_file *seq, void *v)
2013 {
2014 if (v == SEQ_START_TOKEN)
2015 seq_puts(seq,
2016 "sk Eth Pid Groups "
2017 "Rmem Wmem Dump Locks Drops Inode\n");
2018 else {
2019 struct sock *s = v;
2020 struct netlink_sock *nlk = nlk_sk(s);
2021
2022 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %-8d %-8d %-8lu\n",
2023 s,
2024 s->sk_protocol,
2025 nlk->pid,
2026 nlk->groups ? (u32)nlk->groups[0] : 0,
2027 sk_rmem_alloc_get(s),
2028 sk_wmem_alloc_get(s),
2029 nlk->cb,
2030 atomic_read(&s->sk_refcnt),
2031 atomic_read(&s->sk_drops),
2032 sock_i_ino(s)
2033 );
2034
2035 }
2036 return 0;
2037 }
2038
2039 static const struct seq_operations netlink_seq_ops = {
2040 .start = netlink_seq_start,
2041 .next = netlink_seq_next,
2042 .stop = netlink_seq_stop,
2043 .show = netlink_seq_show,
2044 };
2045
2046
2047 static int netlink_seq_open(struct inode *inode, struct file *file)
2048 {
2049 return seq_open_net(inode, file, &netlink_seq_ops,
2050 sizeof(struct nl_seq_iter));
2051 }
2052
2053 static const struct file_operations netlink_seq_fops = {
2054 .owner = THIS_MODULE,
2055 .open = netlink_seq_open,
2056 .read = seq_read,
2057 .llseek = seq_lseek,
2058 .release = seq_release_net,
2059 };
2060
2061 #endif
2062
2063 int netlink_register_notifier(struct notifier_block *nb)
2064 {
2065 return atomic_notifier_chain_register(&netlink_chain, nb);
2066 }
2067 EXPORT_SYMBOL(netlink_register_notifier);
2068
2069 int netlink_unregister_notifier(struct notifier_block *nb)
2070 {
2071 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2072 }
2073 EXPORT_SYMBOL(netlink_unregister_notifier);
2074
2075 static const struct proto_ops netlink_ops = {
2076 .family = PF_NETLINK,
2077 .owner = THIS_MODULE,
2078 .release = netlink_release,
2079 .bind = netlink_bind,
2080 .connect = netlink_connect,
2081 .socketpair = sock_no_socketpair,
2082 .accept = sock_no_accept,
2083 .getname = netlink_getname,
2084 .poll = datagram_poll,
2085 .ioctl = sock_no_ioctl,
2086 .listen = sock_no_listen,
2087 .shutdown = sock_no_shutdown,
2088 .setsockopt = netlink_setsockopt,
2089 .getsockopt = netlink_getsockopt,
2090 .sendmsg = netlink_sendmsg,
2091 .recvmsg = netlink_recvmsg,
2092 .mmap = sock_no_mmap,
2093 .sendpage = sock_no_sendpage,
2094 };
2095
2096 static const struct net_proto_family netlink_family_ops = {
2097 .family = PF_NETLINK,
2098 .create = netlink_create,
2099 .owner = THIS_MODULE, /* for consistency 8) */
2100 };
2101
2102 static int __net_init netlink_net_init(struct net *net)
2103 {
2104 #ifdef CONFIG_PROC_FS
2105 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2106 return -ENOMEM;
2107 #endif
2108 return 0;
2109 }
2110
2111 static void __net_exit netlink_net_exit(struct net *net)
2112 {
2113 #ifdef CONFIG_PROC_FS
2114 proc_net_remove(net, "netlink");
2115 #endif
2116 }
2117
2118 static struct pernet_operations __net_initdata netlink_net_ops = {
2119 .init = netlink_net_init,
2120 .exit = netlink_net_exit,
2121 };
2122
2123 static int __init netlink_proto_init(void)
2124 {
2125 struct sk_buff *dummy_skb;
2126 int i;
2127 unsigned long limit;
2128 unsigned int order;
2129 int err = proto_register(&netlink_proto, 0);
2130
2131 if (err != 0)
2132 goto out;
2133
2134 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2135
2136 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2137 if (!nl_table)
2138 goto panic;
2139
2140 if (totalram_pages >= (128 * 1024))
2141 limit = totalram_pages >> (21 - PAGE_SHIFT);
2142 else
2143 limit = totalram_pages >> (23 - PAGE_SHIFT);
2144
2145 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2146 limit = (1UL << order) / sizeof(struct hlist_head);
2147 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2148
2149 for (i = 0; i < MAX_LINKS; i++) {
2150 struct nl_pid_hash *hash = &nl_table[i].hash;
2151
2152 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
2153 if (!hash->table) {
2154 while (i-- > 0)
2155 nl_pid_hash_free(nl_table[i].hash.table,
2156 1 * sizeof(*hash->table));
2157 kfree(nl_table);
2158 goto panic;
2159 }
2160 hash->max_shift = order;
2161 hash->shift = 0;
2162 hash->mask = 0;
2163 hash->rehash_time = jiffies;
2164 }
2165
2166 sock_register(&netlink_family_ops);
2167 register_pernet_subsys(&netlink_net_ops);
2168 /* The netlink device handler may be needed early. */
2169 rtnetlink_init();
2170 out:
2171 return err;
2172 panic:
2173 panic("netlink_init: Cannot allocate nl_table\n");
2174 }
2175
2176 core_initcall(netlink_proto_init);
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree