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Merge commit 'kumar/next' into next
[deliverable/linux.git] / net / netlink / af_netlink.c
1 /*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
13 * added netlink_proto_exit
14 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
15 * use nlk_sk, as sk->protinfo is on a diet 8)
16 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
17 * - inc module use count of module that owns
18 * the kernel socket in case userspace opens
19 * socket of same protocol
20 * - remove all module support, since netlink is
21 * mandatory if CONFIG_NET=y these days
22 */
23
24 #include <linux/module.h>
25
26 #include <linux/capability.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/signal.h>
30 #include <linux/sched.h>
31 #include <linux/errno.h>
32 #include <linux/string.h>
33 #include <linux/stat.h>
34 #include <linux/socket.h>
35 #include <linux/un.h>
36 #include <linux/fcntl.h>
37 #include <linux/termios.h>
38 #include <linux/sockios.h>
39 #include <linux/net.h>
40 #include <linux/fs.h>
41 #include <linux/slab.h>
42 #include <asm/uaccess.h>
43 #include <linux/skbuff.h>
44 #include <linux/netdevice.h>
45 #include <linux/rtnetlink.h>
46 #include <linux/proc_fs.h>
47 #include <linux/seq_file.h>
48 #include <linux/notifier.h>
49 #include <linux/security.h>
50 #include <linux/jhash.h>
51 #include <linux/jiffies.h>
52 #include <linux/random.h>
53 #include <linux/bitops.h>
54 #include <linux/mm.h>
55 #include <linux/types.h>
56 #include <linux/audit.h>
57 #include <linux/mutex.h>
58
59 #include <net/net_namespace.h>
60 #include <net/sock.h>
61 #include <net/scm.h>
62 #include <net/netlink.h>
63
64 #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
65 #define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long))
66
67 struct netlink_sock {
68 /* struct sock has to be the first member of netlink_sock */
69 struct sock sk;
70 u32 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 #define NETLINK_KERNEL_SOCKET 0x1
87 #define NETLINK_RECV_PKTINFO 0x2
88
89 static inline struct netlink_sock *nlk_sk(struct sock *sk)
90 {
91 return container_of(sk, struct netlink_sock, sk);
92 }
93
94 static inline int netlink_is_kernel(struct sock *sk)
95 {
96 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
97 }
98
99 struct nl_pid_hash {
100 struct hlist_head *table;
101 unsigned long rehash_time;
102
103 unsigned int mask;
104 unsigned int shift;
105
106 unsigned int entries;
107 unsigned int max_shift;
108
109 u32 rnd;
110 };
111
112 struct netlink_table {
113 struct nl_pid_hash hash;
114 struct hlist_head mc_list;
115 unsigned long *listeners;
116 unsigned int nl_nonroot;
117 unsigned int groups;
118 struct mutex *cb_mutex;
119 struct module *module;
120 int registered;
121 };
122
123 static struct netlink_table *nl_table;
124
125 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
126
127 static int netlink_dump(struct sock *sk);
128 static void netlink_destroy_callback(struct netlink_callback *cb);
129
130 static DEFINE_RWLOCK(nl_table_lock);
131 static atomic_t nl_table_users = ATOMIC_INIT(0);
132
133 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
134
135 static u32 netlink_group_mask(u32 group)
136 {
137 return group ? 1 << (group - 1) : 0;
138 }
139
140 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
141 {
142 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
143 }
144
145 static void netlink_sock_destruct(struct sock *sk)
146 {
147 struct netlink_sock *nlk = nlk_sk(sk);
148
149 if (nlk->cb) {
150 if (nlk->cb->done)
151 nlk->cb->done(nlk->cb);
152 netlink_destroy_callback(nlk->cb);
153 }
154
155 skb_queue_purge(&sk->sk_receive_queue);
156
157 if (!sock_flag(sk, SOCK_DEAD)) {
158 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
159 return;
160 }
161
162 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
163 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
164 WARN_ON(nlk_sk(sk)->groups);
165 }
166
167 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
168 * SMP. Look, when several writers sleep and reader wakes them up, all but one
169 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
170 * this, _but_ remember, it adds useless work on UP machines.
171 */
172
173 static void netlink_table_grab(void)
174 __acquires(nl_table_lock)
175 {
176 write_lock_irq(&nl_table_lock);
177
178 if (atomic_read(&nl_table_users)) {
179 DECLARE_WAITQUEUE(wait, current);
180
181 add_wait_queue_exclusive(&nl_table_wait, &wait);
182 for (;;) {
183 set_current_state(TASK_UNINTERRUPTIBLE);
184 if (atomic_read(&nl_table_users) == 0)
185 break;
186 write_unlock_irq(&nl_table_lock);
187 schedule();
188 write_lock_irq(&nl_table_lock);
189 }
190
191 __set_current_state(TASK_RUNNING);
192 remove_wait_queue(&nl_table_wait, &wait);
193 }
194 }
195
196 static void netlink_table_ungrab(void)
197 __releases(nl_table_lock)
198 {
199 write_unlock_irq(&nl_table_lock);
200 wake_up(&nl_table_wait);
201 }
202
203 static inline void
204 netlink_lock_table(void)
205 {
206 /* read_lock() synchronizes us to netlink_table_grab */
207
208 read_lock(&nl_table_lock);
209 atomic_inc(&nl_table_users);
210 read_unlock(&nl_table_lock);
211 }
212
213 static inline void
214 netlink_unlock_table(void)
215 {
216 if (atomic_dec_and_test(&nl_table_users))
217 wake_up(&nl_table_wait);
218 }
219
220 static inline struct sock *netlink_lookup(struct net *net, int protocol,
221 u32 pid)
222 {
223 struct nl_pid_hash *hash = &nl_table[protocol].hash;
224 struct hlist_head *head;
225 struct sock *sk;
226 struct hlist_node *node;
227
228 read_lock(&nl_table_lock);
229 head = nl_pid_hashfn(hash, pid);
230 sk_for_each(sk, node, head) {
231 if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) {
232 sock_hold(sk);
233 goto found;
234 }
235 }
236 sk = NULL;
237 found:
238 read_unlock(&nl_table_lock);
239 return sk;
240 }
241
242 static inline struct hlist_head *nl_pid_hash_zalloc(size_t size)
243 {
244 if (size <= PAGE_SIZE)
245 return kzalloc(size, GFP_ATOMIC);
246 else
247 return (struct hlist_head *)
248 __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
249 get_order(size));
250 }
251
252 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
253 {
254 if (size <= PAGE_SIZE)
255 kfree(table);
256 else
257 free_pages((unsigned long)table, get_order(size));
258 }
259
260 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
261 {
262 unsigned int omask, mask, shift;
263 size_t osize, size;
264 struct hlist_head *otable, *table;
265 int i;
266
267 omask = mask = hash->mask;
268 osize = size = (mask + 1) * sizeof(*table);
269 shift = hash->shift;
270
271 if (grow) {
272 if (++shift > hash->max_shift)
273 return 0;
274 mask = mask * 2 + 1;
275 size *= 2;
276 }
277
278 table = nl_pid_hash_zalloc(size);
279 if (!table)
280 return 0;
281
282 otable = hash->table;
283 hash->table = table;
284 hash->mask = mask;
285 hash->shift = shift;
286 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
287
288 for (i = 0; i <= omask; i++) {
289 struct sock *sk;
290 struct hlist_node *node, *tmp;
291
292 sk_for_each_safe(sk, node, tmp, &otable[i])
293 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
294 }
295
296 nl_pid_hash_free(otable, osize);
297 hash->rehash_time = jiffies + 10 * 60 * HZ;
298 return 1;
299 }
300
301 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
302 {
303 int avg = hash->entries >> hash->shift;
304
305 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
306 return 1;
307
308 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
309 nl_pid_hash_rehash(hash, 0);
310 return 1;
311 }
312
313 return 0;
314 }
315
316 static const struct proto_ops netlink_ops;
317
318 static void
319 netlink_update_listeners(struct sock *sk)
320 {
321 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
322 struct hlist_node *node;
323 unsigned long mask;
324 unsigned int i;
325
326 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
327 mask = 0;
328 sk_for_each_bound(sk, node, &tbl->mc_list) {
329 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
330 mask |= nlk_sk(sk)->groups[i];
331 }
332 tbl->listeners[i] = mask;
333 }
334 /* this function is only called with the netlink table "grabbed", which
335 * makes sure updates are visible before bind or setsockopt return. */
336 }
337
338 static int netlink_insert(struct sock *sk, struct net *net, u32 pid)
339 {
340 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
341 struct hlist_head *head;
342 int err = -EADDRINUSE;
343 struct sock *osk;
344 struct hlist_node *node;
345 int len;
346
347 netlink_table_grab();
348 head = nl_pid_hashfn(hash, pid);
349 len = 0;
350 sk_for_each(osk, node, head) {
351 if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->pid == pid))
352 break;
353 len++;
354 }
355 if (node)
356 goto err;
357
358 err = -EBUSY;
359 if (nlk_sk(sk)->pid)
360 goto err;
361
362 err = -ENOMEM;
363 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
364 goto err;
365
366 if (len && nl_pid_hash_dilute(hash, len))
367 head = nl_pid_hashfn(hash, pid);
368 hash->entries++;
369 nlk_sk(sk)->pid = pid;
370 sk_add_node(sk, head);
371 err = 0;
372
373 err:
374 netlink_table_ungrab();
375 return err;
376 }
377
378 static void netlink_remove(struct sock *sk)
379 {
380 netlink_table_grab();
381 if (sk_del_node_init(sk))
382 nl_table[sk->sk_protocol].hash.entries--;
383 if (nlk_sk(sk)->subscriptions)
384 __sk_del_bind_node(sk);
385 netlink_table_ungrab();
386 }
387
388 static struct proto netlink_proto = {
389 .name = "NETLINK",
390 .owner = THIS_MODULE,
391 .obj_size = sizeof(struct netlink_sock),
392 };
393
394 static int __netlink_create(struct net *net, struct socket *sock,
395 struct mutex *cb_mutex, int protocol)
396 {
397 struct sock *sk;
398 struct netlink_sock *nlk;
399
400 sock->ops = &netlink_ops;
401
402 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
403 if (!sk)
404 return -ENOMEM;
405
406 sock_init_data(sock, sk);
407
408 nlk = nlk_sk(sk);
409 if (cb_mutex)
410 nlk->cb_mutex = cb_mutex;
411 else {
412 nlk->cb_mutex = &nlk->cb_def_mutex;
413 mutex_init(nlk->cb_mutex);
414 }
415 init_waitqueue_head(&nlk->wait);
416
417 sk->sk_destruct = netlink_sock_destruct;
418 sk->sk_protocol = protocol;
419 return 0;
420 }
421
422 static int netlink_create(struct net *net, struct socket *sock, int protocol)
423 {
424 struct module *module = NULL;
425 struct mutex *cb_mutex;
426 struct netlink_sock *nlk;
427 int err = 0;
428
429 sock->state = SS_UNCONNECTED;
430
431 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
432 return -ESOCKTNOSUPPORT;
433
434 if (protocol < 0 || protocol >= MAX_LINKS)
435 return -EPROTONOSUPPORT;
436
437 netlink_lock_table();
438 #ifdef CONFIG_MODULES
439 if (!nl_table[protocol].registered) {
440 netlink_unlock_table();
441 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
442 netlink_lock_table();
443 }
444 #endif
445 if (nl_table[protocol].registered &&
446 try_module_get(nl_table[protocol].module))
447 module = nl_table[protocol].module;
448 cb_mutex = nl_table[protocol].cb_mutex;
449 netlink_unlock_table();
450
451 err = __netlink_create(net, sock, cb_mutex, protocol);
452 if (err < 0)
453 goto out_module;
454
455 local_bh_disable();
456 sock_prot_inuse_add(net, &netlink_proto, 1);
457 local_bh_enable();
458
459 nlk = nlk_sk(sock->sk);
460 nlk->module = module;
461 out:
462 return err;
463
464 out_module:
465 module_put(module);
466 goto out;
467 }
468
469 static int netlink_release(struct socket *sock)
470 {
471 struct sock *sk = sock->sk;
472 struct netlink_sock *nlk;
473
474 if (!sk)
475 return 0;
476
477 netlink_remove(sk);
478 sock_orphan(sk);
479 nlk = nlk_sk(sk);
480
481 /*
482 * OK. Socket is unlinked, any packets that arrive now
483 * will be purged.
484 */
485
486 sock->sk = NULL;
487 wake_up_interruptible_all(&nlk->wait);
488
489 skb_queue_purge(&sk->sk_write_queue);
490
491 if (nlk->pid && !nlk->subscriptions) {
492 struct netlink_notify n = {
493 .net = sock_net(sk),
494 .protocol = sk->sk_protocol,
495 .pid = nlk->pid,
496 };
497 atomic_notifier_call_chain(&netlink_chain,
498 NETLINK_URELEASE, &n);
499 }
500
501 module_put(nlk->module);
502
503 netlink_table_grab();
504 if (netlink_is_kernel(sk)) {
505 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
506 if (--nl_table[sk->sk_protocol].registered == 0) {
507 kfree(nl_table[sk->sk_protocol].listeners);
508 nl_table[sk->sk_protocol].module = NULL;
509 nl_table[sk->sk_protocol].registered = 0;
510 }
511 } else if (nlk->subscriptions)
512 netlink_update_listeners(sk);
513 netlink_table_ungrab();
514
515 kfree(nlk->groups);
516 nlk->groups = NULL;
517
518 local_bh_disable();
519 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
520 local_bh_enable();
521 sock_put(sk);
522 return 0;
523 }
524
525 static int netlink_autobind(struct socket *sock)
526 {
527 struct sock *sk = sock->sk;
528 struct net *net = sock_net(sk);
529 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
530 struct hlist_head *head;
531 struct sock *osk;
532 struct hlist_node *node;
533 s32 pid = current->tgid;
534 int err;
535 static s32 rover = -4097;
536
537 retry:
538 cond_resched();
539 netlink_table_grab();
540 head = nl_pid_hashfn(hash, pid);
541 sk_for_each(osk, node, head) {
542 if (!net_eq(sock_net(osk), net))
543 continue;
544 if (nlk_sk(osk)->pid == pid) {
545 /* Bind collision, search negative pid values. */
546 pid = rover--;
547 if (rover > -4097)
548 rover = -4097;
549 netlink_table_ungrab();
550 goto retry;
551 }
552 }
553 netlink_table_ungrab();
554
555 err = netlink_insert(sk, net, pid);
556 if (err == -EADDRINUSE)
557 goto retry;
558
559 /* If 2 threads race to autobind, that is fine. */
560 if (err == -EBUSY)
561 err = 0;
562
563 return err;
564 }
565
566 static inline int netlink_capable(struct socket *sock, unsigned int flag)
567 {
568 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
569 capable(CAP_NET_ADMIN);
570 }
571
572 static void
573 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
574 {
575 struct netlink_sock *nlk = nlk_sk(sk);
576
577 if (nlk->subscriptions && !subscriptions)
578 __sk_del_bind_node(sk);
579 else if (!nlk->subscriptions && subscriptions)
580 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
581 nlk->subscriptions = subscriptions;
582 }
583
584 static int netlink_realloc_groups(struct sock *sk)
585 {
586 struct netlink_sock *nlk = nlk_sk(sk);
587 unsigned int groups;
588 unsigned long *new_groups;
589 int err = 0;
590
591 netlink_table_grab();
592
593 groups = nl_table[sk->sk_protocol].groups;
594 if (!nl_table[sk->sk_protocol].registered) {
595 err = -ENOENT;
596 goto out_unlock;
597 }
598
599 if (nlk->ngroups >= groups)
600 goto out_unlock;
601
602 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
603 if (new_groups == NULL) {
604 err = -ENOMEM;
605 goto out_unlock;
606 }
607 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
608 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
609
610 nlk->groups = new_groups;
611 nlk->ngroups = groups;
612 out_unlock:
613 netlink_table_ungrab();
614 return err;
615 }
616
617 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
618 int addr_len)
619 {
620 struct sock *sk = sock->sk;
621 struct net *net = sock_net(sk);
622 struct netlink_sock *nlk = nlk_sk(sk);
623 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
624 int err;
625
626 if (nladdr->nl_family != AF_NETLINK)
627 return -EINVAL;
628
629 /* Only superuser is allowed to listen multicasts */
630 if (nladdr->nl_groups) {
631 if (!netlink_capable(sock, NL_NONROOT_RECV))
632 return -EPERM;
633 err = netlink_realloc_groups(sk);
634 if (err)
635 return err;
636 }
637
638 if (nlk->pid) {
639 if (nladdr->nl_pid != nlk->pid)
640 return -EINVAL;
641 } else {
642 err = nladdr->nl_pid ?
643 netlink_insert(sk, net, nladdr->nl_pid) :
644 netlink_autobind(sock);
645 if (err)
646 return err;
647 }
648
649 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
650 return 0;
651
652 netlink_table_grab();
653 netlink_update_subscriptions(sk, nlk->subscriptions +
654 hweight32(nladdr->nl_groups) -
655 hweight32(nlk->groups[0]));
656 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
657 netlink_update_listeners(sk);
658 netlink_table_ungrab();
659
660 return 0;
661 }
662
663 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
664 int alen, int flags)
665 {
666 int err = 0;
667 struct sock *sk = sock->sk;
668 struct netlink_sock *nlk = nlk_sk(sk);
669 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
670
671 if (addr->sa_family == AF_UNSPEC) {
672 sk->sk_state = NETLINK_UNCONNECTED;
673 nlk->dst_pid = 0;
674 nlk->dst_group = 0;
675 return 0;
676 }
677 if (addr->sa_family != AF_NETLINK)
678 return -EINVAL;
679
680 /* Only superuser is allowed to send multicasts */
681 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
682 return -EPERM;
683
684 if (!nlk->pid)
685 err = netlink_autobind(sock);
686
687 if (err == 0) {
688 sk->sk_state = NETLINK_CONNECTED;
689 nlk->dst_pid = nladdr->nl_pid;
690 nlk->dst_group = ffs(nladdr->nl_groups);
691 }
692
693 return err;
694 }
695
696 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
697 int *addr_len, int peer)
698 {
699 struct sock *sk = sock->sk;
700 struct netlink_sock *nlk = nlk_sk(sk);
701 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
702
703 nladdr->nl_family = AF_NETLINK;
704 nladdr->nl_pad = 0;
705 *addr_len = sizeof(*nladdr);
706
707 if (peer) {
708 nladdr->nl_pid = nlk->dst_pid;
709 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
710 } else {
711 nladdr->nl_pid = nlk->pid;
712 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
713 }
714 return 0;
715 }
716
717 static void netlink_overrun(struct sock *sk)
718 {
719 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
720 sk->sk_err = ENOBUFS;
721 sk->sk_error_report(sk);
722 }
723 }
724
725 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
726 {
727 struct sock *sock;
728 struct netlink_sock *nlk;
729
730 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid);
731 if (!sock)
732 return ERR_PTR(-ECONNREFUSED);
733
734 /* Don't bother queuing skb if kernel socket has no input function */
735 nlk = nlk_sk(sock);
736 if (sock->sk_state == NETLINK_CONNECTED &&
737 nlk->dst_pid != nlk_sk(ssk)->pid) {
738 sock_put(sock);
739 return ERR_PTR(-ECONNREFUSED);
740 }
741 return sock;
742 }
743
744 struct sock *netlink_getsockbyfilp(struct file *filp)
745 {
746 struct inode *inode = filp->f_path.dentry->d_inode;
747 struct sock *sock;
748
749 if (!S_ISSOCK(inode->i_mode))
750 return ERR_PTR(-ENOTSOCK);
751
752 sock = SOCKET_I(inode)->sk;
753 if (sock->sk_family != AF_NETLINK)
754 return ERR_PTR(-EINVAL);
755
756 sock_hold(sock);
757 return sock;
758 }
759
760 /*
761 * Attach a skb to a netlink socket.
762 * The caller must hold a reference to the destination socket. On error, the
763 * reference is dropped. The skb is not send to the destination, just all
764 * all error checks are performed and memory in the queue is reserved.
765 * Return values:
766 * < 0: error. skb freed, reference to sock dropped.
767 * 0: continue
768 * 1: repeat lookup - reference dropped while waiting for socket memory.
769 */
770 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
771 long *timeo, struct sock *ssk)
772 {
773 struct netlink_sock *nlk;
774
775 nlk = nlk_sk(sk);
776
777 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
778 test_bit(0, &nlk->state)) {
779 DECLARE_WAITQUEUE(wait, current);
780 if (!*timeo) {
781 if (!ssk || netlink_is_kernel(ssk))
782 netlink_overrun(sk);
783 sock_put(sk);
784 kfree_skb(skb);
785 return -EAGAIN;
786 }
787
788 __set_current_state(TASK_INTERRUPTIBLE);
789 add_wait_queue(&nlk->wait, &wait);
790
791 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
792 test_bit(0, &nlk->state)) &&
793 !sock_flag(sk, SOCK_DEAD))
794 *timeo = schedule_timeout(*timeo);
795
796 __set_current_state(TASK_RUNNING);
797 remove_wait_queue(&nlk->wait, &wait);
798 sock_put(sk);
799
800 if (signal_pending(current)) {
801 kfree_skb(skb);
802 return sock_intr_errno(*timeo);
803 }
804 return 1;
805 }
806 skb_set_owner_r(skb, sk);
807 return 0;
808 }
809
810 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
811 {
812 int len = skb->len;
813
814 skb_queue_tail(&sk->sk_receive_queue, skb);
815 sk->sk_data_ready(sk, len);
816 sock_put(sk);
817 return len;
818 }
819
820 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
821 {
822 kfree_skb(skb);
823 sock_put(sk);
824 }
825
826 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
827 gfp_t allocation)
828 {
829 int delta;
830
831 skb_orphan(skb);
832
833 delta = skb->end - skb->tail;
834 if (delta * 2 < skb->truesize)
835 return skb;
836
837 if (skb_shared(skb)) {
838 struct sk_buff *nskb = skb_clone(skb, allocation);
839 if (!nskb)
840 return skb;
841 kfree_skb(skb);
842 skb = nskb;
843 }
844
845 if (!pskb_expand_head(skb, 0, -delta, allocation))
846 skb->truesize -= delta;
847
848 return skb;
849 }
850
851 static inline void netlink_rcv_wake(struct sock *sk)
852 {
853 struct netlink_sock *nlk = nlk_sk(sk);
854
855 if (skb_queue_empty(&sk->sk_receive_queue))
856 clear_bit(0, &nlk->state);
857 if (!test_bit(0, &nlk->state))
858 wake_up_interruptible(&nlk->wait);
859 }
860
861 static inline int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb)
862 {
863 int ret;
864 struct netlink_sock *nlk = nlk_sk(sk);
865
866 ret = -ECONNREFUSED;
867 if (nlk->netlink_rcv != NULL) {
868 ret = skb->len;
869 skb_set_owner_r(skb, sk);
870 nlk->netlink_rcv(skb);
871 }
872 kfree_skb(skb);
873 sock_put(sk);
874 return ret;
875 }
876
877 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
878 u32 pid, int nonblock)
879 {
880 struct sock *sk;
881 int err;
882 long timeo;
883
884 skb = netlink_trim(skb, gfp_any());
885
886 timeo = sock_sndtimeo(ssk, nonblock);
887 retry:
888 sk = netlink_getsockbypid(ssk, pid);
889 if (IS_ERR(sk)) {
890 kfree_skb(skb);
891 return PTR_ERR(sk);
892 }
893 if (netlink_is_kernel(sk))
894 return netlink_unicast_kernel(sk, skb);
895
896 if (sk_filter(sk, skb)) {
897 err = skb->len;
898 kfree_skb(skb);
899 sock_put(sk);
900 return err;
901 }
902
903 err = netlink_attachskb(sk, skb, &timeo, ssk);
904 if (err == 1)
905 goto retry;
906 if (err)
907 return err;
908
909 return netlink_sendskb(sk, skb);
910 }
911 EXPORT_SYMBOL(netlink_unicast);
912
913 int netlink_has_listeners(struct sock *sk, unsigned int group)
914 {
915 int res = 0;
916 unsigned long *listeners;
917
918 BUG_ON(!netlink_is_kernel(sk));
919
920 rcu_read_lock();
921 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
922
923 if (group - 1 < nl_table[sk->sk_protocol].groups)
924 res = test_bit(group - 1, listeners);
925
926 rcu_read_unlock();
927
928 return res;
929 }
930 EXPORT_SYMBOL_GPL(netlink_has_listeners);
931
932 static inline int netlink_broadcast_deliver(struct sock *sk,
933 struct sk_buff *skb)
934 {
935 struct netlink_sock *nlk = nlk_sk(sk);
936
937 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
938 !test_bit(0, &nlk->state)) {
939 skb_set_owner_r(skb, sk);
940 skb_queue_tail(&sk->sk_receive_queue, skb);
941 sk->sk_data_ready(sk, skb->len);
942 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
943 }
944 return -1;
945 }
946
947 struct netlink_broadcast_data {
948 struct sock *exclude_sk;
949 struct net *net;
950 u32 pid;
951 u32 group;
952 int failure;
953 int congested;
954 int delivered;
955 gfp_t allocation;
956 struct sk_buff *skb, *skb2;
957 };
958
959 static inline int do_one_broadcast(struct sock *sk,
960 struct netlink_broadcast_data *p)
961 {
962 struct netlink_sock *nlk = nlk_sk(sk);
963 int val;
964
965 if (p->exclude_sk == sk)
966 goto out;
967
968 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
969 !test_bit(p->group - 1, nlk->groups))
970 goto out;
971
972 if (!net_eq(sock_net(sk), p->net))
973 goto out;
974
975 if (p->failure) {
976 netlink_overrun(sk);
977 goto out;
978 }
979
980 sock_hold(sk);
981 if (p->skb2 == NULL) {
982 if (skb_shared(p->skb)) {
983 p->skb2 = skb_clone(p->skb, p->allocation);
984 } else {
985 p->skb2 = skb_get(p->skb);
986 /*
987 * skb ownership may have been set when
988 * delivered to a previous socket.
989 */
990 skb_orphan(p->skb2);
991 }
992 }
993 if (p->skb2 == NULL) {
994 netlink_overrun(sk);
995 /* Clone failed. Notify ALL listeners. */
996 p->failure = 1;
997 } else if (sk_filter(sk, p->skb2)) {
998 kfree_skb(p->skb2);
999 p->skb2 = NULL;
1000 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1001 netlink_overrun(sk);
1002 } else {
1003 p->congested |= val;
1004 p->delivered = 1;
1005 p->skb2 = NULL;
1006 }
1007 sock_put(sk);
1008
1009 out:
1010 return 0;
1011 }
1012
1013 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
1014 u32 group, gfp_t allocation)
1015 {
1016 struct net *net = sock_net(ssk);
1017 struct netlink_broadcast_data info;
1018 struct hlist_node *node;
1019 struct sock *sk;
1020
1021 skb = netlink_trim(skb, allocation);
1022
1023 info.exclude_sk = ssk;
1024 info.net = net;
1025 info.pid = pid;
1026 info.group = group;
1027 info.failure = 0;
1028 info.congested = 0;
1029 info.delivered = 0;
1030 info.allocation = allocation;
1031 info.skb = skb;
1032 info.skb2 = NULL;
1033
1034 /* While we sleep in clone, do not allow to change socket list */
1035
1036 netlink_lock_table();
1037
1038 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1039 do_one_broadcast(sk, &info);
1040
1041 kfree_skb(skb);
1042
1043 netlink_unlock_table();
1044
1045 if (info.skb2)
1046 kfree_skb(info.skb2);
1047
1048 if (info.delivered) {
1049 if (info.congested && (allocation & __GFP_WAIT))
1050 yield();
1051 return 0;
1052 }
1053 if (info.failure)
1054 return -ENOBUFS;
1055 return -ESRCH;
1056 }
1057 EXPORT_SYMBOL(netlink_broadcast);
1058
1059 struct netlink_set_err_data {
1060 struct sock *exclude_sk;
1061 u32 pid;
1062 u32 group;
1063 int code;
1064 };
1065
1066 static inline int do_one_set_err(struct sock *sk,
1067 struct netlink_set_err_data *p)
1068 {
1069 struct netlink_sock *nlk = nlk_sk(sk);
1070
1071 if (sk == p->exclude_sk)
1072 goto out;
1073
1074 if (sock_net(sk) != sock_net(p->exclude_sk))
1075 goto out;
1076
1077 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1078 !test_bit(p->group - 1, nlk->groups))
1079 goto out;
1080
1081 sk->sk_err = p->code;
1082 sk->sk_error_report(sk);
1083 out:
1084 return 0;
1085 }
1086
1087 /**
1088 * netlink_set_err - report error to broadcast listeners
1089 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1090 * @pid: the PID of a process that we want to skip (if any)
1091 * @groups: the broadcast group that will notice the error
1092 * @code: error code, must be negative (as usual in kernelspace)
1093 */
1094 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1095 {
1096 struct netlink_set_err_data info;
1097 struct hlist_node *node;
1098 struct sock *sk;
1099
1100 info.exclude_sk = ssk;
1101 info.pid = pid;
1102 info.group = group;
1103 /* sk->sk_err wants a positive error value */
1104 info.code = -code;
1105
1106 read_lock(&nl_table_lock);
1107
1108 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1109 do_one_set_err(sk, &info);
1110
1111 read_unlock(&nl_table_lock);
1112 }
1113
1114 /* must be called with netlink table grabbed */
1115 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1116 unsigned int group,
1117 int is_new)
1118 {
1119 int old, new = !!is_new, subscriptions;
1120
1121 old = test_bit(group - 1, nlk->groups);
1122 subscriptions = nlk->subscriptions - old + new;
1123 if (new)
1124 __set_bit(group - 1, nlk->groups);
1125 else
1126 __clear_bit(group - 1, nlk->groups);
1127 netlink_update_subscriptions(&nlk->sk, subscriptions);
1128 netlink_update_listeners(&nlk->sk);
1129 }
1130
1131 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1132 char __user *optval, int optlen)
1133 {
1134 struct sock *sk = sock->sk;
1135 struct netlink_sock *nlk = nlk_sk(sk);
1136 unsigned int val = 0;
1137 int err;
1138
1139 if (level != SOL_NETLINK)
1140 return -ENOPROTOOPT;
1141
1142 if (optlen >= sizeof(int) &&
1143 get_user(val, (unsigned int __user *)optval))
1144 return -EFAULT;
1145
1146 switch (optname) {
1147 case NETLINK_PKTINFO:
1148 if (val)
1149 nlk->flags |= NETLINK_RECV_PKTINFO;
1150 else
1151 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1152 err = 0;
1153 break;
1154 case NETLINK_ADD_MEMBERSHIP:
1155 case NETLINK_DROP_MEMBERSHIP: {
1156 if (!netlink_capable(sock, NL_NONROOT_RECV))
1157 return -EPERM;
1158 err = netlink_realloc_groups(sk);
1159 if (err)
1160 return err;
1161 if (!val || val - 1 >= nlk->ngroups)
1162 return -EINVAL;
1163 netlink_table_grab();
1164 netlink_update_socket_mc(nlk, val,
1165 optname == NETLINK_ADD_MEMBERSHIP);
1166 netlink_table_ungrab();
1167 err = 0;
1168 break;
1169 }
1170 default:
1171 err = -ENOPROTOOPT;
1172 }
1173 return err;
1174 }
1175
1176 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1177 char __user *optval, int __user *optlen)
1178 {
1179 struct sock *sk = sock->sk;
1180 struct netlink_sock *nlk = nlk_sk(sk);
1181 int len, val, err;
1182
1183 if (level != SOL_NETLINK)
1184 return -ENOPROTOOPT;
1185
1186 if (get_user(len, optlen))
1187 return -EFAULT;
1188 if (len < 0)
1189 return -EINVAL;
1190
1191 switch (optname) {
1192 case NETLINK_PKTINFO:
1193 if (len < sizeof(int))
1194 return -EINVAL;
1195 len = sizeof(int);
1196 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1197 if (put_user(len, optlen) ||
1198 put_user(val, optval))
1199 return -EFAULT;
1200 err = 0;
1201 break;
1202 default:
1203 err = -ENOPROTOOPT;
1204 }
1205 return err;
1206 }
1207
1208 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1209 {
1210 struct nl_pktinfo info;
1211
1212 info.group = NETLINK_CB(skb).dst_group;
1213 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1214 }
1215
1216 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1217 struct msghdr *msg, size_t len)
1218 {
1219 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1220 struct sock *sk = sock->sk;
1221 struct netlink_sock *nlk = nlk_sk(sk);
1222 struct sockaddr_nl *addr = msg->msg_name;
1223 u32 dst_pid;
1224 u32 dst_group;
1225 struct sk_buff *skb;
1226 int err;
1227 struct scm_cookie scm;
1228
1229 if (msg->msg_flags&MSG_OOB)
1230 return -EOPNOTSUPP;
1231
1232 if (NULL == siocb->scm)
1233 siocb->scm = &scm;
1234 err = scm_send(sock, msg, siocb->scm);
1235 if (err < 0)
1236 return err;
1237
1238 if (msg->msg_namelen) {
1239 if (addr->nl_family != AF_NETLINK)
1240 return -EINVAL;
1241 dst_pid = addr->nl_pid;
1242 dst_group = ffs(addr->nl_groups);
1243 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1244 return -EPERM;
1245 } else {
1246 dst_pid = nlk->dst_pid;
1247 dst_group = nlk->dst_group;
1248 }
1249
1250 if (!nlk->pid) {
1251 err = netlink_autobind(sock);
1252 if (err)
1253 goto out;
1254 }
1255
1256 err = -EMSGSIZE;
1257 if (len > sk->sk_sndbuf - 32)
1258 goto out;
1259 err = -ENOBUFS;
1260 skb = alloc_skb(len, GFP_KERNEL);
1261 if (skb == NULL)
1262 goto out;
1263
1264 NETLINK_CB(skb).pid = nlk->pid;
1265 NETLINK_CB(skb).dst_group = dst_group;
1266 NETLINK_CB(skb).loginuid = audit_get_loginuid(current);
1267 NETLINK_CB(skb).sessionid = audit_get_sessionid(current);
1268 security_task_getsecid(current, &(NETLINK_CB(skb).sid));
1269 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1270
1271 /* What can I do? Netlink is asynchronous, so that
1272 we will have to save current capabilities to
1273 check them, when this message will be delivered
1274 to corresponding kernel module. --ANK (980802)
1275 */
1276
1277 err = -EFAULT;
1278 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1279 kfree_skb(skb);
1280 goto out;
1281 }
1282
1283 err = security_netlink_send(sk, skb);
1284 if (err) {
1285 kfree_skb(skb);
1286 goto out;
1287 }
1288
1289 if (dst_group) {
1290 atomic_inc(&skb->users);
1291 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1292 }
1293 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1294
1295 out:
1296 return err;
1297 }
1298
1299 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1300 struct msghdr *msg, size_t len,
1301 int flags)
1302 {
1303 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1304 struct scm_cookie scm;
1305 struct sock *sk = sock->sk;
1306 struct netlink_sock *nlk = nlk_sk(sk);
1307 int noblock = flags&MSG_DONTWAIT;
1308 size_t copied;
1309 struct sk_buff *skb;
1310 int err;
1311
1312 if (flags&MSG_OOB)
1313 return -EOPNOTSUPP;
1314
1315 copied = 0;
1316
1317 skb = skb_recv_datagram(sk, flags, noblock, &err);
1318 if (skb == NULL)
1319 goto out;
1320
1321 msg->msg_namelen = 0;
1322
1323 copied = skb->len;
1324 if (len < copied) {
1325 msg->msg_flags |= MSG_TRUNC;
1326 copied = len;
1327 }
1328
1329 skb_reset_transport_header(skb);
1330 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1331
1332 if (msg->msg_name) {
1333 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1334 addr->nl_family = AF_NETLINK;
1335 addr->nl_pad = 0;
1336 addr->nl_pid = NETLINK_CB(skb).pid;
1337 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1338 msg->msg_namelen = sizeof(*addr);
1339 }
1340
1341 if (nlk->flags & NETLINK_RECV_PKTINFO)
1342 netlink_cmsg_recv_pktinfo(msg, skb);
1343
1344 if (NULL == siocb->scm) {
1345 memset(&scm, 0, sizeof(scm));
1346 siocb->scm = &scm;
1347 }
1348 siocb->scm->creds = *NETLINK_CREDS(skb);
1349 if (flags & MSG_TRUNC)
1350 copied = skb->len;
1351 skb_free_datagram(sk, skb);
1352
1353 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1354 netlink_dump(sk);
1355
1356 scm_recv(sock, msg, siocb->scm, flags);
1357 out:
1358 netlink_rcv_wake(sk);
1359 return err ? : copied;
1360 }
1361
1362 static void netlink_data_ready(struct sock *sk, int len)
1363 {
1364 BUG();
1365 }
1366
1367 /*
1368 * We export these functions to other modules. They provide a
1369 * complete set of kernel non-blocking support for message
1370 * queueing.
1371 */
1372
1373 struct sock *
1374 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1375 void (*input)(struct sk_buff *skb),
1376 struct mutex *cb_mutex, struct module *module)
1377 {
1378 struct socket *sock;
1379 struct sock *sk;
1380 struct netlink_sock *nlk;
1381 unsigned long *listeners = NULL;
1382
1383 BUG_ON(!nl_table);
1384
1385 if (unit < 0 || unit >= MAX_LINKS)
1386 return NULL;
1387
1388 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1389 return NULL;
1390
1391 /*
1392 * We have to just have a reference on the net from sk, but don't
1393 * get_net it. Besides, we cannot get and then put the net here.
1394 * So we create one inside init_net and the move it to net.
1395 */
1396
1397 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1398 goto out_sock_release_nosk;
1399
1400 sk = sock->sk;
1401 sk_change_net(sk, net);
1402
1403 if (groups < 32)
1404 groups = 32;
1405
1406 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
1407 if (!listeners)
1408 goto out_sock_release;
1409
1410 sk->sk_data_ready = netlink_data_ready;
1411 if (input)
1412 nlk_sk(sk)->netlink_rcv = input;
1413
1414 if (netlink_insert(sk, net, 0))
1415 goto out_sock_release;
1416
1417 nlk = nlk_sk(sk);
1418 nlk->flags |= NETLINK_KERNEL_SOCKET;
1419
1420 netlink_table_grab();
1421 if (!nl_table[unit].registered) {
1422 nl_table[unit].groups = groups;
1423 nl_table[unit].listeners = listeners;
1424 nl_table[unit].cb_mutex = cb_mutex;
1425 nl_table[unit].module = module;
1426 nl_table[unit].registered = 1;
1427 } else {
1428 kfree(listeners);
1429 nl_table[unit].registered++;
1430 }
1431 netlink_table_ungrab();
1432 return sk;
1433
1434 out_sock_release:
1435 kfree(listeners);
1436 netlink_kernel_release(sk);
1437 return NULL;
1438
1439 out_sock_release_nosk:
1440 sock_release(sock);
1441 return NULL;
1442 }
1443 EXPORT_SYMBOL(netlink_kernel_create);
1444
1445
1446 void
1447 netlink_kernel_release(struct sock *sk)
1448 {
1449 sk_release_kernel(sk);
1450 }
1451 EXPORT_SYMBOL(netlink_kernel_release);
1452
1453
1454 /**
1455 * netlink_change_ngroups - change number of multicast groups
1456 *
1457 * This changes the number of multicast groups that are available
1458 * on a certain netlink family. Note that it is not possible to
1459 * change the number of groups to below 32. Also note that it does
1460 * not implicitly call netlink_clear_multicast_users() when the
1461 * number of groups is reduced.
1462 *
1463 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1464 * @groups: The new number of groups.
1465 */
1466 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1467 {
1468 unsigned long *listeners, *old = NULL;
1469 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1470 int err = 0;
1471
1472 if (groups < 32)
1473 groups = 32;
1474
1475 netlink_table_grab();
1476 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1477 listeners = kzalloc(NLGRPSZ(groups), GFP_ATOMIC);
1478 if (!listeners) {
1479 err = -ENOMEM;
1480 goto out_ungrab;
1481 }
1482 old = tbl->listeners;
1483 memcpy(listeners, old, NLGRPSZ(tbl->groups));
1484 rcu_assign_pointer(tbl->listeners, listeners);
1485 }
1486 tbl->groups = groups;
1487
1488 out_ungrab:
1489 netlink_table_ungrab();
1490 synchronize_rcu();
1491 kfree(old);
1492 return err;
1493 }
1494 EXPORT_SYMBOL(netlink_change_ngroups);
1495
1496 /**
1497 * netlink_clear_multicast_users - kick off multicast listeners
1498 *
1499 * This function removes all listeners from the given group.
1500 * @ksk: The kernel netlink socket, as returned by
1501 * netlink_kernel_create().
1502 * @group: The multicast group to clear.
1503 */
1504 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1505 {
1506 struct sock *sk;
1507 struct hlist_node *node;
1508 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1509
1510 netlink_table_grab();
1511
1512 sk_for_each_bound(sk, node, &tbl->mc_list)
1513 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1514
1515 netlink_table_ungrab();
1516 }
1517 EXPORT_SYMBOL(netlink_clear_multicast_users);
1518
1519 void netlink_set_nonroot(int protocol, unsigned int flags)
1520 {
1521 if ((unsigned int)protocol < MAX_LINKS)
1522 nl_table[protocol].nl_nonroot = flags;
1523 }
1524 EXPORT_SYMBOL(netlink_set_nonroot);
1525
1526 static void netlink_destroy_callback(struct netlink_callback *cb)
1527 {
1528 if (cb->skb)
1529 kfree_skb(cb->skb);
1530 kfree(cb);
1531 }
1532
1533 /*
1534 * It looks a bit ugly.
1535 * It would be better to create kernel thread.
1536 */
1537
1538 static int netlink_dump(struct sock *sk)
1539 {
1540 struct netlink_sock *nlk = nlk_sk(sk);
1541 struct netlink_callback *cb;
1542 struct sk_buff *skb;
1543 struct nlmsghdr *nlh;
1544 int len, err = -ENOBUFS;
1545
1546 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1547 if (!skb)
1548 goto errout;
1549
1550 mutex_lock(nlk->cb_mutex);
1551
1552 cb = nlk->cb;
1553 if (cb == NULL) {
1554 err = -EINVAL;
1555 goto errout_skb;
1556 }
1557
1558 len = cb->dump(skb, cb);
1559
1560 if (len > 0) {
1561 mutex_unlock(nlk->cb_mutex);
1562
1563 if (sk_filter(sk, skb))
1564 kfree_skb(skb);
1565 else {
1566 skb_queue_tail(&sk->sk_receive_queue, skb);
1567 sk->sk_data_ready(sk, skb->len);
1568 }
1569 return 0;
1570 }
1571
1572 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1573 if (!nlh)
1574 goto errout_skb;
1575
1576 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1577
1578 if (sk_filter(sk, skb))
1579 kfree_skb(skb);
1580 else {
1581 skb_queue_tail(&sk->sk_receive_queue, skb);
1582 sk->sk_data_ready(sk, skb->len);
1583 }
1584
1585 if (cb->done)
1586 cb->done(cb);
1587 nlk->cb = NULL;
1588 mutex_unlock(nlk->cb_mutex);
1589
1590 netlink_destroy_callback(cb);
1591 return 0;
1592
1593 errout_skb:
1594 mutex_unlock(nlk->cb_mutex);
1595 kfree_skb(skb);
1596 errout:
1597 return err;
1598 }
1599
1600 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1601 struct nlmsghdr *nlh,
1602 int (*dump)(struct sk_buff *skb,
1603 struct netlink_callback *),
1604 int (*done)(struct netlink_callback *))
1605 {
1606 struct netlink_callback *cb;
1607 struct sock *sk;
1608 struct netlink_sock *nlk;
1609
1610 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1611 if (cb == NULL)
1612 return -ENOBUFS;
1613
1614 cb->dump = dump;
1615 cb->done = done;
1616 cb->nlh = nlh;
1617 atomic_inc(&skb->users);
1618 cb->skb = skb;
1619
1620 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1621 if (sk == NULL) {
1622 netlink_destroy_callback(cb);
1623 return -ECONNREFUSED;
1624 }
1625 nlk = nlk_sk(sk);
1626 /* A dump is in progress... */
1627 mutex_lock(nlk->cb_mutex);
1628 if (nlk->cb) {
1629 mutex_unlock(nlk->cb_mutex);
1630 netlink_destroy_callback(cb);
1631 sock_put(sk);
1632 return -EBUSY;
1633 }
1634 nlk->cb = cb;
1635 mutex_unlock(nlk->cb_mutex);
1636
1637 netlink_dump(sk);
1638 sock_put(sk);
1639
1640 /* We successfully started a dump, by returning -EINTR we
1641 * signal not to send ACK even if it was requested.
1642 */
1643 return -EINTR;
1644 }
1645 EXPORT_SYMBOL(netlink_dump_start);
1646
1647 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1648 {
1649 struct sk_buff *skb;
1650 struct nlmsghdr *rep;
1651 struct nlmsgerr *errmsg;
1652 size_t payload = sizeof(*errmsg);
1653
1654 /* error messages get the original request appened */
1655 if (err)
1656 payload += nlmsg_len(nlh);
1657
1658 skb = nlmsg_new(payload, GFP_KERNEL);
1659 if (!skb) {
1660 struct sock *sk;
1661
1662 sk = netlink_lookup(sock_net(in_skb->sk),
1663 in_skb->sk->sk_protocol,
1664 NETLINK_CB(in_skb).pid);
1665 if (sk) {
1666 sk->sk_err = ENOBUFS;
1667 sk->sk_error_report(sk);
1668 sock_put(sk);
1669 }
1670 return;
1671 }
1672
1673 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1674 NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
1675 errmsg = nlmsg_data(rep);
1676 errmsg->error = err;
1677 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1678 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1679 }
1680 EXPORT_SYMBOL(netlink_ack);
1681
1682 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1683 struct nlmsghdr *))
1684 {
1685 struct nlmsghdr *nlh;
1686 int err;
1687
1688 while (skb->len >= nlmsg_total_size(0)) {
1689 int msglen;
1690
1691 nlh = nlmsg_hdr(skb);
1692 err = 0;
1693
1694 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1695 return 0;
1696
1697 /* Only requests are handled by the kernel */
1698 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1699 goto ack;
1700
1701 /* Skip control messages */
1702 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1703 goto ack;
1704
1705 err = cb(skb, nlh);
1706 if (err == -EINTR)
1707 goto skip;
1708
1709 ack:
1710 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1711 netlink_ack(skb, nlh, err);
1712
1713 skip:
1714 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1715 if (msglen > skb->len)
1716 msglen = skb->len;
1717 skb_pull(skb, msglen);
1718 }
1719
1720 return 0;
1721 }
1722 EXPORT_SYMBOL(netlink_rcv_skb);
1723
1724 /**
1725 * nlmsg_notify - send a notification netlink message
1726 * @sk: netlink socket to use
1727 * @skb: notification message
1728 * @pid: destination netlink pid for reports or 0
1729 * @group: destination multicast group or 0
1730 * @report: 1 to report back, 0 to disable
1731 * @flags: allocation flags
1732 */
1733 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1734 unsigned int group, int report, gfp_t flags)
1735 {
1736 int err = 0;
1737
1738 if (group) {
1739 int exclude_pid = 0;
1740
1741 if (report) {
1742 atomic_inc(&skb->users);
1743 exclude_pid = pid;
1744 }
1745
1746 /* errors reported via destination sk->sk_err */
1747 nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1748 }
1749
1750 if (report)
1751 err = nlmsg_unicast(sk, skb, pid);
1752
1753 return err;
1754 }
1755 EXPORT_SYMBOL(nlmsg_notify);
1756
1757 #ifdef CONFIG_PROC_FS
1758 struct nl_seq_iter {
1759 struct seq_net_private p;
1760 int link;
1761 int hash_idx;
1762 };
1763
1764 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1765 {
1766 struct nl_seq_iter *iter = seq->private;
1767 int i, j;
1768 struct sock *s;
1769 struct hlist_node *node;
1770 loff_t off = 0;
1771
1772 for (i = 0; i < MAX_LINKS; i++) {
1773 struct nl_pid_hash *hash = &nl_table[i].hash;
1774
1775 for (j = 0; j <= hash->mask; j++) {
1776 sk_for_each(s, node, &hash->table[j]) {
1777 if (sock_net(s) != seq_file_net(seq))
1778 continue;
1779 if (off == pos) {
1780 iter->link = i;
1781 iter->hash_idx = j;
1782 return s;
1783 }
1784 ++off;
1785 }
1786 }
1787 }
1788 return NULL;
1789 }
1790
1791 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1792 __acquires(nl_table_lock)
1793 {
1794 read_lock(&nl_table_lock);
1795 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1796 }
1797
1798 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1799 {
1800 struct sock *s;
1801 struct nl_seq_iter *iter;
1802 int i, j;
1803
1804 ++*pos;
1805
1806 if (v == SEQ_START_TOKEN)
1807 return netlink_seq_socket_idx(seq, 0);
1808
1809 iter = seq->private;
1810 s = v;
1811 do {
1812 s = sk_next(s);
1813 } while (s && sock_net(s) != seq_file_net(seq));
1814 if (s)
1815 return s;
1816
1817 i = iter->link;
1818 j = iter->hash_idx + 1;
1819
1820 do {
1821 struct nl_pid_hash *hash = &nl_table[i].hash;
1822
1823 for (; j <= hash->mask; j++) {
1824 s = sk_head(&hash->table[j]);
1825 while (s && sock_net(s) != seq_file_net(seq))
1826 s = sk_next(s);
1827 if (s) {
1828 iter->link = i;
1829 iter->hash_idx = j;
1830 return s;
1831 }
1832 }
1833
1834 j = 0;
1835 } while (++i < MAX_LINKS);
1836
1837 return NULL;
1838 }
1839
1840 static void netlink_seq_stop(struct seq_file *seq, void *v)
1841 __releases(nl_table_lock)
1842 {
1843 read_unlock(&nl_table_lock);
1844 }
1845
1846
1847 static int netlink_seq_show(struct seq_file *seq, void *v)
1848 {
1849 if (v == SEQ_START_TOKEN)
1850 seq_puts(seq,
1851 "sk Eth Pid Groups "
1852 "Rmem Wmem Dump Locks\n");
1853 else {
1854 struct sock *s = v;
1855 struct netlink_sock *nlk = nlk_sk(s);
1856
1857 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
1858 s,
1859 s->sk_protocol,
1860 nlk->pid,
1861 nlk->groups ? (u32)nlk->groups[0] : 0,
1862 atomic_read(&s->sk_rmem_alloc),
1863 atomic_read(&s->sk_wmem_alloc),
1864 nlk->cb,
1865 atomic_read(&s->sk_refcnt)
1866 );
1867
1868 }
1869 return 0;
1870 }
1871
1872 static const struct seq_operations netlink_seq_ops = {
1873 .start = netlink_seq_start,
1874 .next = netlink_seq_next,
1875 .stop = netlink_seq_stop,
1876 .show = netlink_seq_show,
1877 };
1878
1879
1880 static int netlink_seq_open(struct inode *inode, struct file *file)
1881 {
1882 return seq_open_net(inode, file, &netlink_seq_ops,
1883 sizeof(struct nl_seq_iter));
1884 }
1885
1886 static const struct file_operations netlink_seq_fops = {
1887 .owner = THIS_MODULE,
1888 .open = netlink_seq_open,
1889 .read = seq_read,
1890 .llseek = seq_lseek,
1891 .release = seq_release_net,
1892 };
1893
1894 #endif
1895
1896 int netlink_register_notifier(struct notifier_block *nb)
1897 {
1898 return atomic_notifier_chain_register(&netlink_chain, nb);
1899 }
1900 EXPORT_SYMBOL(netlink_register_notifier);
1901
1902 int netlink_unregister_notifier(struct notifier_block *nb)
1903 {
1904 return atomic_notifier_chain_unregister(&netlink_chain, nb);
1905 }
1906 EXPORT_SYMBOL(netlink_unregister_notifier);
1907
1908 static const struct proto_ops netlink_ops = {
1909 .family = PF_NETLINK,
1910 .owner = THIS_MODULE,
1911 .release = netlink_release,
1912 .bind = netlink_bind,
1913 .connect = netlink_connect,
1914 .socketpair = sock_no_socketpair,
1915 .accept = sock_no_accept,
1916 .getname = netlink_getname,
1917 .poll = datagram_poll,
1918 .ioctl = sock_no_ioctl,
1919 .listen = sock_no_listen,
1920 .shutdown = sock_no_shutdown,
1921 .setsockopt = netlink_setsockopt,
1922 .getsockopt = netlink_getsockopt,
1923 .sendmsg = netlink_sendmsg,
1924 .recvmsg = netlink_recvmsg,
1925 .mmap = sock_no_mmap,
1926 .sendpage = sock_no_sendpage,
1927 };
1928
1929 static struct net_proto_family netlink_family_ops = {
1930 .family = PF_NETLINK,
1931 .create = netlink_create,
1932 .owner = THIS_MODULE, /* for consistency 8) */
1933 };
1934
1935 static int __net_init netlink_net_init(struct net *net)
1936 {
1937 #ifdef CONFIG_PROC_FS
1938 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
1939 return -ENOMEM;
1940 #endif
1941 return 0;
1942 }
1943
1944 static void __net_exit netlink_net_exit(struct net *net)
1945 {
1946 #ifdef CONFIG_PROC_FS
1947 proc_net_remove(net, "netlink");
1948 #endif
1949 }
1950
1951 static struct pernet_operations __net_initdata netlink_net_ops = {
1952 .init = netlink_net_init,
1953 .exit = netlink_net_exit,
1954 };
1955
1956 static int __init netlink_proto_init(void)
1957 {
1958 struct sk_buff *dummy_skb;
1959 int i;
1960 unsigned long limit;
1961 unsigned int order;
1962 int err = proto_register(&netlink_proto, 0);
1963
1964 if (err != 0)
1965 goto out;
1966
1967 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
1968
1969 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
1970 if (!nl_table)
1971 goto panic;
1972
1973 if (num_physpages >= (128 * 1024))
1974 limit = num_physpages >> (21 - PAGE_SHIFT);
1975 else
1976 limit = num_physpages >> (23 - PAGE_SHIFT);
1977
1978 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
1979 limit = (1UL << order) / sizeof(struct hlist_head);
1980 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
1981
1982 for (i = 0; i < MAX_LINKS; i++) {
1983 struct nl_pid_hash *hash = &nl_table[i].hash;
1984
1985 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
1986 if (!hash->table) {
1987 while (i-- > 0)
1988 nl_pid_hash_free(nl_table[i].hash.table,
1989 1 * sizeof(*hash->table));
1990 kfree(nl_table);
1991 goto panic;
1992 }
1993 hash->max_shift = order;
1994 hash->shift = 0;
1995 hash->mask = 0;
1996 hash->rehash_time = jiffies;
1997 }
1998
1999 sock_register(&netlink_family_ops);
2000 register_pernet_subsys(&netlink_net_ops);
2001 /* The netlink device handler may be needed early. */
2002 rtnetlink_init();
2003 out:
2004 return err;
2005 panic:
2006 panic("netlink_init: Cannot allocate nl_table\n");
2007 }
2008
2009 core_initcall(netlink_proto_init);
Linux kernel - Deliverables
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