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Merge branch 'kdb-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel...
[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 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 err = scm_send(sock, msg, siocb->scm);
1329 if (err < 0)
1330 return err;
1331
1332 if (msg->msg_namelen) {
1333 if (addr->nl_family != AF_NETLINK)
1334 return -EINVAL;
1335 dst_pid = addr->nl_pid;
1336 dst_group = ffs(addr->nl_groups);
1337 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1338 return -EPERM;
1339 } else {
1340 dst_pid = nlk->dst_pid;
1341 dst_group = nlk->dst_group;
1342 }
1343
1344 if (!nlk->pid) {
1345 err = netlink_autobind(sock);
1346 if (err)
1347 goto out;
1348 }
1349
1350 err = -EMSGSIZE;
1351 if (len > sk->sk_sndbuf - 32)
1352 goto out;
1353 err = -ENOBUFS;
1354 skb = alloc_skb(len, GFP_KERNEL);
1355 if (skb == NULL)
1356 goto out;
1357
1358 NETLINK_CB(skb).pid = nlk->pid;
1359 NETLINK_CB(skb).dst_group = dst_group;
1360 NETLINK_CB(skb).loginuid = audit_get_loginuid(current);
1361 NETLINK_CB(skb).sessionid = audit_get_sessionid(current);
1362 security_task_getsecid(current, &(NETLINK_CB(skb).sid));
1363 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1364
1365 /* What can I do? Netlink is asynchronous, so that
1366 we will have to save current capabilities to
1367 check them, when this message will be delivered
1368 to corresponding kernel module. --ANK (980802)
1369 */
1370
1371 err = -EFAULT;
1372 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1373 kfree_skb(skb);
1374 goto out;
1375 }
1376
1377 err = security_netlink_send(sk, skb);
1378 if (err) {
1379 kfree_skb(skb);
1380 goto out;
1381 }
1382
1383 if (dst_group) {
1384 atomic_inc(&skb->users);
1385 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1386 }
1387 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1388
1389 out:
1390 return err;
1391 }
1392
1393 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1394 struct msghdr *msg, size_t len,
1395 int flags)
1396 {
1397 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1398 struct scm_cookie scm;
1399 struct sock *sk = sock->sk;
1400 struct netlink_sock *nlk = nlk_sk(sk);
1401 int noblock = flags&MSG_DONTWAIT;
1402 size_t copied;
1403 struct sk_buff *skb, *frag __maybe_unused = NULL;
1404 int err;
1405
1406 if (flags&MSG_OOB)
1407 return -EOPNOTSUPP;
1408
1409 copied = 0;
1410
1411 skb = skb_recv_datagram(sk, flags, noblock, &err);
1412 if (skb == NULL)
1413 goto out;
1414
1415 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1416 if (unlikely(skb_shinfo(skb)->frag_list)) {
1417 bool need_compat = !!(flags & MSG_CMSG_COMPAT);
1418
1419 /*
1420 * If this skb has a frag_list, then here that means that
1421 * we will have to use the frag_list skb for compat tasks
1422 * and the regular skb for non-compat tasks.
1423 *
1424 * The skb might (and likely will) be cloned, so we can't
1425 * just reset frag_list and go on with things -- we need to
1426 * keep that. For the compat case that's easy -- simply get
1427 * a reference to the compat skb and free the regular one
1428 * including the frag. For the non-compat case, we need to
1429 * avoid sending the frag to the user -- so assign NULL but
1430 * restore it below before freeing the skb.
1431 */
1432 if (need_compat) {
1433 struct sk_buff *compskb = skb_shinfo(skb)->frag_list;
1434 skb_get(compskb);
1435 kfree_skb(skb);
1436 skb = compskb;
1437 } else {
1438 frag = skb_shinfo(skb)->frag_list;
1439 skb_shinfo(skb)->frag_list = NULL;
1440 }
1441 }
1442 #endif
1443
1444 msg->msg_namelen = 0;
1445
1446 copied = skb->len;
1447 if (len < copied) {
1448 msg->msg_flags |= MSG_TRUNC;
1449 copied = len;
1450 }
1451
1452 skb_reset_transport_header(skb);
1453 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1454
1455 if (msg->msg_name) {
1456 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1457 addr->nl_family = AF_NETLINK;
1458 addr->nl_pad = 0;
1459 addr->nl_pid = NETLINK_CB(skb).pid;
1460 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1461 msg->msg_namelen = sizeof(*addr);
1462 }
1463
1464 if (nlk->flags & NETLINK_RECV_PKTINFO)
1465 netlink_cmsg_recv_pktinfo(msg, skb);
1466
1467 if (NULL == siocb->scm) {
1468 memset(&scm, 0, sizeof(scm));
1469 siocb->scm = &scm;
1470 }
1471 siocb->scm->creds = *NETLINK_CREDS(skb);
1472 if (flags & MSG_TRUNC)
1473 copied = skb->len;
1474
1475 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1476 skb_shinfo(skb)->frag_list = frag;
1477 #endif
1478
1479 skb_free_datagram(sk, skb);
1480
1481 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1482 netlink_dump(sk);
1483
1484 scm_recv(sock, msg, siocb->scm, flags);
1485 out:
1486 netlink_rcv_wake(sk);
1487 return err ? : copied;
1488 }
1489
1490 static void netlink_data_ready(struct sock *sk, int len)
1491 {
1492 BUG();
1493 }
1494
1495 /*
1496 * We export these functions to other modules. They provide a
1497 * complete set of kernel non-blocking support for message
1498 * queueing.
1499 */
1500
1501 struct sock *
1502 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1503 void (*input)(struct sk_buff *skb),
1504 struct mutex *cb_mutex, struct module *module)
1505 {
1506 struct socket *sock;
1507 struct sock *sk;
1508 struct netlink_sock *nlk;
1509 unsigned long *listeners = NULL;
1510
1511 BUG_ON(!nl_table);
1512
1513 if (unit < 0 || unit >= MAX_LINKS)
1514 return NULL;
1515
1516 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1517 return NULL;
1518
1519 /*
1520 * We have to just have a reference on the net from sk, but don't
1521 * get_net it. Besides, we cannot get and then put the net here.
1522 * So we create one inside init_net and the move it to net.
1523 */
1524
1525 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1526 goto out_sock_release_nosk;
1527
1528 sk = sock->sk;
1529 sk_change_net(sk, net);
1530
1531 if (groups < 32)
1532 groups = 32;
1533
1534 listeners = kzalloc(NLGRPSZ(groups) + sizeof(struct listeners_rcu_head),
1535 GFP_KERNEL);
1536 if (!listeners)
1537 goto out_sock_release;
1538
1539 sk->sk_data_ready = netlink_data_ready;
1540 if (input)
1541 nlk_sk(sk)->netlink_rcv = input;
1542
1543 if (netlink_insert(sk, net, 0))
1544 goto out_sock_release;
1545
1546 nlk = nlk_sk(sk);
1547 nlk->flags |= NETLINK_KERNEL_SOCKET;
1548
1549 netlink_table_grab();
1550 if (!nl_table[unit].registered) {
1551 nl_table[unit].groups = groups;
1552 nl_table[unit].listeners = listeners;
1553 nl_table[unit].cb_mutex = cb_mutex;
1554 nl_table[unit].module = module;
1555 nl_table[unit].registered = 1;
1556 } else {
1557 kfree(listeners);
1558 nl_table[unit].registered++;
1559 }
1560 netlink_table_ungrab();
1561 return sk;
1562
1563 out_sock_release:
1564 kfree(listeners);
1565 netlink_kernel_release(sk);
1566 return NULL;
1567
1568 out_sock_release_nosk:
1569 sock_release(sock);
1570 return NULL;
1571 }
1572 EXPORT_SYMBOL(netlink_kernel_create);
1573
1574
1575 void
1576 netlink_kernel_release(struct sock *sk)
1577 {
1578 sk_release_kernel(sk);
1579 }
1580 EXPORT_SYMBOL(netlink_kernel_release);
1581
1582
1583 static void netlink_free_old_listeners(struct rcu_head *rcu_head)
1584 {
1585 struct listeners_rcu_head *lrh;
1586
1587 lrh = container_of(rcu_head, struct listeners_rcu_head, rcu_head);
1588 kfree(lrh->ptr);
1589 }
1590
1591 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1592 {
1593 unsigned long *listeners, *old = NULL;
1594 struct listeners_rcu_head *old_rcu_head;
1595 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1596
1597 if (groups < 32)
1598 groups = 32;
1599
1600 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1601 listeners = kzalloc(NLGRPSZ(groups) +
1602 sizeof(struct listeners_rcu_head),
1603 GFP_ATOMIC);
1604 if (!listeners)
1605 return -ENOMEM;
1606 old = tbl->listeners;
1607 memcpy(listeners, old, NLGRPSZ(tbl->groups));
1608 rcu_assign_pointer(tbl->listeners, listeners);
1609 /*
1610 * Free the old memory after an RCU grace period so we
1611 * don't leak it. We use call_rcu() here in order to be
1612 * able to call this function from atomic contexts. The
1613 * allocation of this memory will have reserved enough
1614 * space for struct listeners_rcu_head at the end.
1615 */
1616 old_rcu_head = (void *)(tbl->listeners +
1617 NLGRPLONGS(tbl->groups));
1618 old_rcu_head->ptr = old;
1619 call_rcu(&old_rcu_head->rcu_head, netlink_free_old_listeners);
1620 }
1621 tbl->groups = groups;
1622
1623 return 0;
1624 }
1625
1626 /**
1627 * netlink_change_ngroups - change number of multicast groups
1628 *
1629 * This changes the number of multicast groups that are available
1630 * on a certain netlink family. Note that it is not possible to
1631 * change the number of groups to below 32. Also note that it does
1632 * not implicitly call netlink_clear_multicast_users() when the
1633 * number of groups is reduced.
1634 *
1635 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1636 * @groups: The new number of groups.
1637 */
1638 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1639 {
1640 int err;
1641
1642 netlink_table_grab();
1643 err = __netlink_change_ngroups(sk, groups);
1644 netlink_table_ungrab();
1645
1646 return err;
1647 }
1648
1649 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1650 {
1651 struct sock *sk;
1652 struct hlist_node *node;
1653 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1654
1655 sk_for_each_bound(sk, node, &tbl->mc_list)
1656 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1657 }
1658
1659 /**
1660 * netlink_clear_multicast_users - kick off multicast listeners
1661 *
1662 * This function removes all listeners from the given group.
1663 * @ksk: The kernel netlink socket, as returned by
1664 * netlink_kernel_create().
1665 * @group: The multicast group to clear.
1666 */
1667 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1668 {
1669 netlink_table_grab();
1670 __netlink_clear_multicast_users(ksk, group);
1671 netlink_table_ungrab();
1672 }
1673
1674 void netlink_set_nonroot(int protocol, unsigned int flags)
1675 {
1676 if ((unsigned int)protocol < MAX_LINKS)
1677 nl_table[protocol].nl_nonroot = flags;
1678 }
1679 EXPORT_SYMBOL(netlink_set_nonroot);
1680
1681 static void netlink_destroy_callback(struct netlink_callback *cb)
1682 {
1683 kfree_skb(cb->skb);
1684 kfree(cb);
1685 }
1686
1687 /*
1688 * It looks a bit ugly.
1689 * It would be better to create kernel thread.
1690 */
1691
1692 static int netlink_dump(struct sock *sk)
1693 {
1694 struct netlink_sock *nlk = nlk_sk(sk);
1695 struct netlink_callback *cb;
1696 struct sk_buff *skb;
1697 struct nlmsghdr *nlh;
1698 int len, err = -ENOBUFS;
1699
1700 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1701 if (!skb)
1702 goto errout;
1703
1704 mutex_lock(nlk->cb_mutex);
1705
1706 cb = nlk->cb;
1707 if (cb == NULL) {
1708 err = -EINVAL;
1709 goto errout_skb;
1710 }
1711
1712 len = cb->dump(skb, cb);
1713
1714 if (len > 0) {
1715 mutex_unlock(nlk->cb_mutex);
1716
1717 if (sk_filter(sk, skb))
1718 kfree_skb(skb);
1719 else {
1720 skb_queue_tail(&sk->sk_receive_queue, skb);
1721 sk->sk_data_ready(sk, skb->len);
1722 }
1723 return 0;
1724 }
1725
1726 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1727 if (!nlh)
1728 goto errout_skb;
1729
1730 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1731
1732 if (sk_filter(sk, skb))
1733 kfree_skb(skb);
1734 else {
1735 skb_queue_tail(&sk->sk_receive_queue, skb);
1736 sk->sk_data_ready(sk, skb->len);
1737 }
1738
1739 if (cb->done)
1740 cb->done(cb);
1741 nlk->cb = NULL;
1742 mutex_unlock(nlk->cb_mutex);
1743
1744 netlink_destroy_callback(cb);
1745 return 0;
1746
1747 errout_skb:
1748 mutex_unlock(nlk->cb_mutex);
1749 kfree_skb(skb);
1750 errout:
1751 return err;
1752 }
1753
1754 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1755 const struct nlmsghdr *nlh,
1756 int (*dump)(struct sk_buff *skb,
1757 struct netlink_callback *),
1758 int (*done)(struct netlink_callback *))
1759 {
1760 struct netlink_callback *cb;
1761 struct sock *sk;
1762 struct netlink_sock *nlk;
1763
1764 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1765 if (cb == NULL)
1766 return -ENOBUFS;
1767
1768 cb->dump = dump;
1769 cb->done = done;
1770 cb->nlh = nlh;
1771 atomic_inc(&skb->users);
1772 cb->skb = skb;
1773
1774 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1775 if (sk == NULL) {
1776 netlink_destroy_callback(cb);
1777 return -ECONNREFUSED;
1778 }
1779 nlk = nlk_sk(sk);
1780 /* A dump is in progress... */
1781 mutex_lock(nlk->cb_mutex);
1782 if (nlk->cb) {
1783 mutex_unlock(nlk->cb_mutex);
1784 netlink_destroy_callback(cb);
1785 sock_put(sk);
1786 return -EBUSY;
1787 }
1788 nlk->cb = cb;
1789 mutex_unlock(nlk->cb_mutex);
1790
1791 netlink_dump(sk);
1792 sock_put(sk);
1793
1794 /* We successfully started a dump, by returning -EINTR we
1795 * signal not to send ACK even if it was requested.
1796 */
1797 return -EINTR;
1798 }
1799 EXPORT_SYMBOL(netlink_dump_start);
1800
1801 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1802 {
1803 struct sk_buff *skb;
1804 struct nlmsghdr *rep;
1805 struct nlmsgerr *errmsg;
1806 size_t payload = sizeof(*errmsg);
1807
1808 /* error messages get the original request appened */
1809 if (err)
1810 payload += nlmsg_len(nlh);
1811
1812 skb = nlmsg_new(payload, GFP_KERNEL);
1813 if (!skb) {
1814 struct sock *sk;
1815
1816 sk = netlink_lookup(sock_net(in_skb->sk),
1817 in_skb->sk->sk_protocol,
1818 NETLINK_CB(in_skb).pid);
1819 if (sk) {
1820 sk->sk_err = ENOBUFS;
1821 sk->sk_error_report(sk);
1822 sock_put(sk);
1823 }
1824 return;
1825 }
1826
1827 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1828 NLMSG_ERROR, payload, 0);
1829 errmsg = nlmsg_data(rep);
1830 errmsg->error = err;
1831 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1832 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1833 }
1834 EXPORT_SYMBOL(netlink_ack);
1835
1836 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1837 struct nlmsghdr *))
1838 {
1839 struct nlmsghdr *nlh;
1840 int err;
1841
1842 while (skb->len >= nlmsg_total_size(0)) {
1843 int msglen;
1844
1845 nlh = nlmsg_hdr(skb);
1846 err = 0;
1847
1848 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1849 return 0;
1850
1851 /* Only requests are handled by the kernel */
1852 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1853 goto ack;
1854
1855 /* Skip control messages */
1856 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1857 goto ack;
1858
1859 err = cb(skb, nlh);
1860 if (err == -EINTR)
1861 goto skip;
1862
1863 ack:
1864 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1865 netlink_ack(skb, nlh, err);
1866
1867 skip:
1868 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1869 if (msglen > skb->len)
1870 msglen = skb->len;
1871 skb_pull(skb, msglen);
1872 }
1873
1874 return 0;
1875 }
1876 EXPORT_SYMBOL(netlink_rcv_skb);
1877
1878 /**
1879 * nlmsg_notify - send a notification netlink message
1880 * @sk: netlink socket to use
1881 * @skb: notification message
1882 * @pid: destination netlink pid for reports or 0
1883 * @group: destination multicast group or 0
1884 * @report: 1 to report back, 0 to disable
1885 * @flags: allocation flags
1886 */
1887 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1888 unsigned int group, int report, gfp_t flags)
1889 {
1890 int err = 0;
1891
1892 if (group) {
1893 int exclude_pid = 0;
1894
1895 if (report) {
1896 atomic_inc(&skb->users);
1897 exclude_pid = pid;
1898 }
1899
1900 /* errors reported via destination sk->sk_err, but propagate
1901 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1902 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1903 }
1904
1905 if (report) {
1906 int err2;
1907
1908 err2 = nlmsg_unicast(sk, skb, pid);
1909 if (!err || err == -ESRCH)
1910 err = err2;
1911 }
1912
1913 return err;
1914 }
1915 EXPORT_SYMBOL(nlmsg_notify);
1916
1917 #ifdef CONFIG_PROC_FS
1918 struct nl_seq_iter {
1919 struct seq_net_private p;
1920 int link;
1921 int hash_idx;
1922 };
1923
1924 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1925 {
1926 struct nl_seq_iter *iter = seq->private;
1927 int i, j;
1928 struct sock *s;
1929 struct hlist_node *node;
1930 loff_t off = 0;
1931
1932 for (i = 0; i < MAX_LINKS; i++) {
1933 struct nl_pid_hash *hash = &nl_table[i].hash;
1934
1935 for (j = 0; j <= hash->mask; j++) {
1936 sk_for_each(s, node, &hash->table[j]) {
1937 if (sock_net(s) != seq_file_net(seq))
1938 continue;
1939 if (off == pos) {
1940 iter->link = i;
1941 iter->hash_idx = j;
1942 return s;
1943 }
1944 ++off;
1945 }
1946 }
1947 }
1948 return NULL;
1949 }
1950
1951 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1952 __acquires(nl_table_lock)
1953 {
1954 read_lock(&nl_table_lock);
1955 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1956 }
1957
1958 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1959 {
1960 struct sock *s;
1961 struct nl_seq_iter *iter;
1962 int i, j;
1963
1964 ++*pos;
1965
1966 if (v == SEQ_START_TOKEN)
1967 return netlink_seq_socket_idx(seq, 0);
1968
1969 iter = seq->private;
1970 s = v;
1971 do {
1972 s = sk_next(s);
1973 } while (s && sock_net(s) != seq_file_net(seq));
1974 if (s)
1975 return s;
1976
1977 i = iter->link;
1978 j = iter->hash_idx + 1;
1979
1980 do {
1981 struct nl_pid_hash *hash = &nl_table[i].hash;
1982
1983 for (; j <= hash->mask; j++) {
1984 s = sk_head(&hash->table[j]);
1985 while (s && sock_net(s) != seq_file_net(seq))
1986 s = sk_next(s);
1987 if (s) {
1988 iter->link = i;
1989 iter->hash_idx = j;
1990 return s;
1991 }
1992 }
1993
1994 j = 0;
1995 } while (++i < MAX_LINKS);
1996
1997 return NULL;
1998 }
1999
2000 static void netlink_seq_stop(struct seq_file *seq, void *v)
2001 __releases(nl_table_lock)
2002 {
2003 read_unlock(&nl_table_lock);
2004 }
2005
2006
2007 static int netlink_seq_show(struct seq_file *seq, void *v)
2008 {
2009 if (v == SEQ_START_TOKEN)
2010 seq_puts(seq,
2011 "sk Eth Pid Groups "
2012 "Rmem Wmem Dump Locks Drops Inode\n");
2013 else {
2014 struct sock *s = v;
2015 struct netlink_sock *nlk = nlk_sk(s);
2016
2017 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %-8d %-8d %-8lu\n",
2018 s,
2019 s->sk_protocol,
2020 nlk->pid,
2021 nlk->groups ? (u32)nlk->groups[0] : 0,
2022 sk_rmem_alloc_get(s),
2023 sk_wmem_alloc_get(s),
2024 nlk->cb,
2025 atomic_read(&s->sk_refcnt),
2026 atomic_read(&s->sk_drops),
2027 sock_i_ino(s)
2028 );
2029
2030 }
2031 return 0;
2032 }
2033
2034 static const struct seq_operations netlink_seq_ops = {
2035 .start = netlink_seq_start,
2036 .next = netlink_seq_next,
2037 .stop = netlink_seq_stop,
2038 .show = netlink_seq_show,
2039 };
2040
2041
2042 static int netlink_seq_open(struct inode *inode, struct file *file)
2043 {
2044 return seq_open_net(inode, file, &netlink_seq_ops,
2045 sizeof(struct nl_seq_iter));
2046 }
2047
2048 static const struct file_operations netlink_seq_fops = {
2049 .owner = THIS_MODULE,
2050 .open = netlink_seq_open,
2051 .read = seq_read,
2052 .llseek = seq_lseek,
2053 .release = seq_release_net,
2054 };
2055
2056 #endif
2057
2058 int netlink_register_notifier(struct notifier_block *nb)
2059 {
2060 return atomic_notifier_chain_register(&netlink_chain, nb);
2061 }
2062 EXPORT_SYMBOL(netlink_register_notifier);
2063
2064 int netlink_unregister_notifier(struct notifier_block *nb)
2065 {
2066 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2067 }
2068 EXPORT_SYMBOL(netlink_unregister_notifier);
2069
2070 static const struct proto_ops netlink_ops = {
2071 .family = PF_NETLINK,
2072 .owner = THIS_MODULE,
2073 .release = netlink_release,
2074 .bind = netlink_bind,
2075 .connect = netlink_connect,
2076 .socketpair = sock_no_socketpair,
2077 .accept = sock_no_accept,
2078 .getname = netlink_getname,
2079 .poll = datagram_poll,
2080 .ioctl = sock_no_ioctl,
2081 .listen = sock_no_listen,
2082 .shutdown = sock_no_shutdown,
2083 .setsockopt = netlink_setsockopt,
2084 .getsockopt = netlink_getsockopt,
2085 .sendmsg = netlink_sendmsg,
2086 .recvmsg = netlink_recvmsg,
2087 .mmap = sock_no_mmap,
2088 .sendpage = sock_no_sendpage,
2089 };
2090
2091 static const struct net_proto_family netlink_family_ops = {
2092 .family = PF_NETLINK,
2093 .create = netlink_create,
2094 .owner = THIS_MODULE, /* for consistency 8) */
2095 };
2096
2097 static int __net_init netlink_net_init(struct net *net)
2098 {
2099 #ifdef CONFIG_PROC_FS
2100 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2101 return -ENOMEM;
2102 #endif
2103 return 0;
2104 }
2105
2106 static void __net_exit netlink_net_exit(struct net *net)
2107 {
2108 #ifdef CONFIG_PROC_FS
2109 proc_net_remove(net, "netlink");
2110 #endif
2111 }
2112
2113 static struct pernet_operations __net_initdata netlink_net_ops = {
2114 .init = netlink_net_init,
2115 .exit = netlink_net_exit,
2116 };
2117
2118 static int __init netlink_proto_init(void)
2119 {
2120 struct sk_buff *dummy_skb;
2121 int i;
2122 unsigned long limit;
2123 unsigned int order;
2124 int err = proto_register(&netlink_proto, 0);
2125
2126 if (err != 0)
2127 goto out;
2128
2129 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2130
2131 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2132 if (!nl_table)
2133 goto panic;
2134
2135 if (totalram_pages >= (128 * 1024))
2136 limit = totalram_pages >> (21 - PAGE_SHIFT);
2137 else
2138 limit = totalram_pages >> (23 - PAGE_SHIFT);
2139
2140 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2141 limit = (1UL << order) / sizeof(struct hlist_head);
2142 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2143
2144 for (i = 0; i < MAX_LINKS; i++) {
2145 struct nl_pid_hash *hash = &nl_table[i].hash;
2146
2147 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
2148 if (!hash->table) {
2149 while (i-- > 0)
2150 nl_pid_hash_free(nl_table[i].hash.table,
2151 1 * sizeof(*hash->table));
2152 kfree(nl_table);
2153 goto panic;
2154 }
2155 hash->max_shift = order;
2156 hash->shift = 0;
2157 hash->mask = 0;
2158 hash->rehash_time = jiffies;
2159 }
2160
2161 sock_register(&netlink_family_ops);
2162 register_pernet_subsys(&netlink_net_ops);
2163 /* The netlink device handler may be needed early. */
2164 rtnetlink_init();
2165 out:
2166 return err;
2167 panic:
2168 panic("netlink_init: Cannot allocate nl_table\n");
2169 }
2170
2171 core_initcall(netlink_proto_init);
Linux kernel - Deliverables
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