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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[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 {
87 struct rcu_head rcu;
88 unsigned long masks[0];
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 struct listeners __rcu *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 inline u32 netlink_group_mask(u32 group)
143 {
144 return group ? 1 << (group - 1) : 0;
145 }
146
147 static inline 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 struct sock *netlink_lookup(struct net *net, int protocol, u32 pid)
230 {
231 struct nl_pid_hash *hash = &nl_table[protocol].hash;
232 struct hlist_head *head;
233 struct sock *sk;
234 struct hlist_node *node;
235
236 read_lock(&nl_table_lock);
237 head = nl_pid_hashfn(hash, pid);
238 sk_for_each(sk, node, head) {
239 if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) {
240 sock_hold(sk);
241 goto found;
242 }
243 }
244 sk = NULL;
245 found:
246 read_unlock(&nl_table_lock);
247 return sk;
248 }
249
250 static struct hlist_head *nl_pid_hash_zalloc(size_t size)
251 {
252 if (size <= PAGE_SIZE)
253 return kzalloc(size, GFP_ATOMIC);
254 else
255 return (struct hlist_head *)
256 __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
257 get_order(size));
258 }
259
260 static void nl_pid_hash_free(struct hlist_head *table, size_t size)
261 {
262 if (size <= PAGE_SIZE)
263 kfree(table);
264 else
265 free_pages((unsigned long)table, get_order(size));
266 }
267
268 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
269 {
270 unsigned int omask, mask, shift;
271 size_t osize, size;
272 struct hlist_head *otable, *table;
273 int i;
274
275 omask = mask = hash->mask;
276 osize = size = (mask + 1) * sizeof(*table);
277 shift = hash->shift;
278
279 if (grow) {
280 if (++shift > hash->max_shift)
281 return 0;
282 mask = mask * 2 + 1;
283 size *= 2;
284 }
285
286 table = nl_pid_hash_zalloc(size);
287 if (!table)
288 return 0;
289
290 otable = hash->table;
291 hash->table = table;
292 hash->mask = mask;
293 hash->shift = shift;
294 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
295
296 for (i = 0; i <= omask; i++) {
297 struct sock *sk;
298 struct hlist_node *node, *tmp;
299
300 sk_for_each_safe(sk, node, tmp, &otable[i])
301 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
302 }
303
304 nl_pid_hash_free(otable, osize);
305 hash->rehash_time = jiffies + 10 * 60 * HZ;
306 return 1;
307 }
308
309 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
310 {
311 int avg = hash->entries >> hash->shift;
312
313 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
314 return 1;
315
316 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
317 nl_pid_hash_rehash(hash, 0);
318 return 1;
319 }
320
321 return 0;
322 }
323
324 static const struct proto_ops netlink_ops;
325
326 static void
327 netlink_update_listeners(struct sock *sk)
328 {
329 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
330 struct hlist_node *node;
331 unsigned long mask;
332 unsigned int i;
333
334 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
335 mask = 0;
336 sk_for_each_bound(sk, node, &tbl->mc_list) {
337 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
338 mask |= nlk_sk(sk)->groups[i];
339 }
340 tbl->listeners->masks[i] = mask;
341 }
342 /* this function is only called with the netlink table "grabbed", which
343 * makes sure updates are visible before bind or setsockopt return. */
344 }
345
346 static int netlink_insert(struct sock *sk, struct net *net, u32 pid)
347 {
348 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
349 struct hlist_head *head;
350 int err = -EADDRINUSE;
351 struct sock *osk;
352 struct hlist_node *node;
353 int len;
354
355 netlink_table_grab();
356 head = nl_pid_hashfn(hash, pid);
357 len = 0;
358 sk_for_each(osk, node, head) {
359 if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->pid == pid))
360 break;
361 len++;
362 }
363 if (node)
364 goto err;
365
366 err = -EBUSY;
367 if (nlk_sk(sk)->pid)
368 goto err;
369
370 err = -ENOMEM;
371 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
372 goto err;
373
374 if (len && nl_pid_hash_dilute(hash, len))
375 head = nl_pid_hashfn(hash, pid);
376 hash->entries++;
377 nlk_sk(sk)->pid = pid;
378 sk_add_node(sk, head);
379 err = 0;
380
381 err:
382 netlink_table_ungrab();
383 return err;
384 }
385
386 static void netlink_remove(struct sock *sk)
387 {
388 netlink_table_grab();
389 if (sk_del_node_init(sk))
390 nl_table[sk->sk_protocol].hash.entries--;
391 if (nlk_sk(sk)->subscriptions)
392 __sk_del_bind_node(sk);
393 netlink_table_ungrab();
394 }
395
396 static struct proto netlink_proto = {
397 .name = "NETLINK",
398 .owner = THIS_MODULE,
399 .obj_size = sizeof(struct netlink_sock),
400 };
401
402 static int __netlink_create(struct net *net, struct socket *sock,
403 struct mutex *cb_mutex, int protocol)
404 {
405 struct sock *sk;
406 struct netlink_sock *nlk;
407
408 sock->ops = &netlink_ops;
409
410 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
411 if (!sk)
412 return -ENOMEM;
413
414 sock_init_data(sock, sk);
415
416 nlk = nlk_sk(sk);
417 if (cb_mutex)
418 nlk->cb_mutex = cb_mutex;
419 else {
420 nlk->cb_mutex = &nlk->cb_def_mutex;
421 mutex_init(nlk->cb_mutex);
422 }
423 init_waitqueue_head(&nlk->wait);
424
425 sk->sk_destruct = netlink_sock_destruct;
426 sk->sk_protocol = protocol;
427 return 0;
428 }
429
430 static int netlink_create(struct net *net, struct socket *sock, int protocol,
431 int kern)
432 {
433 struct module *module = NULL;
434 struct mutex *cb_mutex;
435 struct netlink_sock *nlk;
436 int err = 0;
437
438 sock->state = SS_UNCONNECTED;
439
440 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
441 return -ESOCKTNOSUPPORT;
442
443 if (protocol < 0 || protocol >= MAX_LINKS)
444 return -EPROTONOSUPPORT;
445
446 netlink_lock_table();
447 #ifdef CONFIG_MODULES
448 if (!nl_table[protocol].registered) {
449 netlink_unlock_table();
450 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
451 netlink_lock_table();
452 }
453 #endif
454 if (nl_table[protocol].registered &&
455 try_module_get(nl_table[protocol].module))
456 module = nl_table[protocol].module;
457 else
458 err = -EPROTONOSUPPORT;
459 cb_mutex = nl_table[protocol].cb_mutex;
460 netlink_unlock_table();
461
462 if (err < 0)
463 goto out;
464
465 err = __netlink_create(net, sock, cb_mutex, protocol);
466 if (err < 0)
467 goto out_module;
468
469 local_bh_disable();
470 sock_prot_inuse_add(net, &netlink_proto, 1);
471 local_bh_enable();
472
473 nlk = nlk_sk(sock->sk);
474 nlk->module = module;
475 out:
476 return err;
477
478 out_module:
479 module_put(module);
480 goto out;
481 }
482
483 static int netlink_release(struct socket *sock)
484 {
485 struct sock *sk = sock->sk;
486 struct netlink_sock *nlk;
487
488 if (!sk)
489 return 0;
490
491 netlink_remove(sk);
492 sock_orphan(sk);
493 nlk = nlk_sk(sk);
494
495 /*
496 * OK. Socket is unlinked, any packets that arrive now
497 * will be purged.
498 */
499
500 sock->sk = NULL;
501 wake_up_interruptible_all(&nlk->wait);
502
503 skb_queue_purge(&sk->sk_write_queue);
504
505 if (nlk->pid) {
506 struct netlink_notify n = {
507 .net = sock_net(sk),
508 .protocol = sk->sk_protocol,
509 .pid = nlk->pid,
510 };
511 atomic_notifier_call_chain(&netlink_chain,
512 NETLINK_URELEASE, &n);
513 }
514
515 module_put(nlk->module);
516
517 netlink_table_grab();
518 if (netlink_is_kernel(sk)) {
519 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
520 if (--nl_table[sk->sk_protocol].registered == 0) {
521 kfree(nl_table[sk->sk_protocol].listeners);
522 nl_table[sk->sk_protocol].module = NULL;
523 nl_table[sk->sk_protocol].registered = 0;
524 }
525 } else if (nlk->subscriptions)
526 netlink_update_listeners(sk);
527 netlink_table_ungrab();
528
529 kfree(nlk->groups);
530 nlk->groups = NULL;
531
532 local_bh_disable();
533 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
534 local_bh_enable();
535 sock_put(sk);
536 return 0;
537 }
538
539 static int netlink_autobind(struct socket *sock)
540 {
541 struct sock *sk = sock->sk;
542 struct net *net = sock_net(sk);
543 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
544 struct hlist_head *head;
545 struct sock *osk;
546 struct hlist_node *node;
547 s32 pid = task_tgid_vnr(current);
548 int err;
549 static s32 rover = -4097;
550
551 retry:
552 cond_resched();
553 netlink_table_grab();
554 head = nl_pid_hashfn(hash, pid);
555 sk_for_each(osk, node, head) {
556 if (!net_eq(sock_net(osk), net))
557 continue;
558 if (nlk_sk(osk)->pid == pid) {
559 /* Bind collision, search negative pid values. */
560 pid = rover--;
561 if (rover > -4097)
562 rover = -4097;
563 netlink_table_ungrab();
564 goto retry;
565 }
566 }
567 netlink_table_ungrab();
568
569 err = netlink_insert(sk, net, pid);
570 if (err == -EADDRINUSE)
571 goto retry;
572
573 /* If 2 threads race to autobind, that is fine. */
574 if (err == -EBUSY)
575 err = 0;
576
577 return err;
578 }
579
580 static inline int netlink_capable(const struct socket *sock, unsigned int flag)
581 {
582 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
583 capable(CAP_NET_ADMIN);
584 }
585
586 static void
587 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
588 {
589 struct netlink_sock *nlk = nlk_sk(sk);
590
591 if (nlk->subscriptions && !subscriptions)
592 __sk_del_bind_node(sk);
593 else if (!nlk->subscriptions && subscriptions)
594 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
595 nlk->subscriptions = subscriptions;
596 }
597
598 static int netlink_realloc_groups(struct sock *sk)
599 {
600 struct netlink_sock *nlk = nlk_sk(sk);
601 unsigned int groups;
602 unsigned long *new_groups;
603 int err = 0;
604
605 netlink_table_grab();
606
607 groups = nl_table[sk->sk_protocol].groups;
608 if (!nl_table[sk->sk_protocol].registered) {
609 err = -ENOENT;
610 goto out_unlock;
611 }
612
613 if (nlk->ngroups >= groups)
614 goto out_unlock;
615
616 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
617 if (new_groups == NULL) {
618 err = -ENOMEM;
619 goto out_unlock;
620 }
621 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
622 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
623
624 nlk->groups = new_groups;
625 nlk->ngroups = groups;
626 out_unlock:
627 netlink_table_ungrab();
628 return err;
629 }
630
631 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
632 int addr_len)
633 {
634 struct sock *sk = sock->sk;
635 struct net *net = sock_net(sk);
636 struct netlink_sock *nlk = nlk_sk(sk);
637 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
638 int err;
639
640 if (nladdr->nl_family != AF_NETLINK)
641 return -EINVAL;
642
643 /* Only superuser is allowed to listen multicasts */
644 if (nladdr->nl_groups) {
645 if (!netlink_capable(sock, NL_NONROOT_RECV))
646 return -EPERM;
647 err = netlink_realloc_groups(sk);
648 if (err)
649 return err;
650 }
651
652 if (nlk->pid) {
653 if (nladdr->nl_pid != nlk->pid)
654 return -EINVAL;
655 } else {
656 err = nladdr->nl_pid ?
657 netlink_insert(sk, net, nladdr->nl_pid) :
658 netlink_autobind(sock);
659 if (err)
660 return err;
661 }
662
663 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
664 return 0;
665
666 netlink_table_grab();
667 netlink_update_subscriptions(sk, nlk->subscriptions +
668 hweight32(nladdr->nl_groups) -
669 hweight32(nlk->groups[0]));
670 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
671 netlink_update_listeners(sk);
672 netlink_table_ungrab();
673
674 return 0;
675 }
676
677 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
678 int alen, int flags)
679 {
680 int err = 0;
681 struct sock *sk = sock->sk;
682 struct netlink_sock *nlk = nlk_sk(sk);
683 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
684
685 if (alen < sizeof(addr->sa_family))
686 return -EINVAL;
687
688 if (addr->sa_family == AF_UNSPEC) {
689 sk->sk_state = NETLINK_UNCONNECTED;
690 nlk->dst_pid = 0;
691 nlk->dst_group = 0;
692 return 0;
693 }
694 if (addr->sa_family != AF_NETLINK)
695 return -EINVAL;
696
697 /* Only superuser is allowed to send multicasts */
698 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
699 return -EPERM;
700
701 if (!nlk->pid)
702 err = netlink_autobind(sock);
703
704 if (err == 0) {
705 sk->sk_state = NETLINK_CONNECTED;
706 nlk->dst_pid = nladdr->nl_pid;
707 nlk->dst_group = ffs(nladdr->nl_groups);
708 }
709
710 return err;
711 }
712
713 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
714 int *addr_len, int peer)
715 {
716 struct sock *sk = sock->sk;
717 struct netlink_sock *nlk = nlk_sk(sk);
718 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
719
720 nladdr->nl_family = AF_NETLINK;
721 nladdr->nl_pad = 0;
722 *addr_len = sizeof(*nladdr);
723
724 if (peer) {
725 nladdr->nl_pid = nlk->dst_pid;
726 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
727 } else {
728 nladdr->nl_pid = nlk->pid;
729 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
730 }
731 return 0;
732 }
733
734 static void netlink_overrun(struct sock *sk)
735 {
736 struct netlink_sock *nlk = nlk_sk(sk);
737
738 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
739 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
740 sk->sk_err = ENOBUFS;
741 sk->sk_error_report(sk);
742 }
743 }
744 atomic_inc(&sk->sk_drops);
745 }
746
747 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
748 {
749 struct sock *sock;
750 struct netlink_sock *nlk;
751
752 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid);
753 if (!sock)
754 return ERR_PTR(-ECONNREFUSED);
755
756 /* Don't bother queuing skb if kernel socket has no input function */
757 nlk = nlk_sk(sock);
758 if (sock->sk_state == NETLINK_CONNECTED &&
759 nlk->dst_pid != nlk_sk(ssk)->pid) {
760 sock_put(sock);
761 return ERR_PTR(-ECONNREFUSED);
762 }
763 return sock;
764 }
765
766 struct sock *netlink_getsockbyfilp(struct file *filp)
767 {
768 struct inode *inode = filp->f_path.dentry->d_inode;
769 struct sock *sock;
770
771 if (!S_ISSOCK(inode->i_mode))
772 return ERR_PTR(-ENOTSOCK);
773
774 sock = SOCKET_I(inode)->sk;
775 if (sock->sk_family != AF_NETLINK)
776 return ERR_PTR(-EINVAL);
777
778 sock_hold(sock);
779 return sock;
780 }
781
782 /*
783 * Attach a skb to a netlink socket.
784 * The caller must hold a reference to the destination socket. On error, the
785 * reference is dropped. The skb is not send to the destination, just all
786 * all error checks are performed and memory in the queue is reserved.
787 * Return values:
788 * < 0: error. skb freed, reference to sock dropped.
789 * 0: continue
790 * 1: repeat lookup - reference dropped while waiting for socket memory.
791 */
792 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
793 long *timeo, struct sock *ssk)
794 {
795 struct netlink_sock *nlk;
796
797 nlk = nlk_sk(sk);
798
799 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
800 test_bit(0, &nlk->state)) {
801 DECLARE_WAITQUEUE(wait, current);
802 if (!*timeo) {
803 if (!ssk || netlink_is_kernel(ssk))
804 netlink_overrun(sk);
805 sock_put(sk);
806 kfree_skb(skb);
807 return -EAGAIN;
808 }
809
810 __set_current_state(TASK_INTERRUPTIBLE);
811 add_wait_queue(&nlk->wait, &wait);
812
813 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
814 test_bit(0, &nlk->state)) &&
815 !sock_flag(sk, SOCK_DEAD))
816 *timeo = schedule_timeout(*timeo);
817
818 __set_current_state(TASK_RUNNING);
819 remove_wait_queue(&nlk->wait, &wait);
820 sock_put(sk);
821
822 if (signal_pending(current)) {
823 kfree_skb(skb);
824 return sock_intr_errno(*timeo);
825 }
826 return 1;
827 }
828 skb_set_owner_r(skb, sk);
829 return 0;
830 }
831
832 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
833 {
834 int len = skb->len;
835
836 skb_queue_tail(&sk->sk_receive_queue, skb);
837 sk->sk_data_ready(sk, len);
838 sock_put(sk);
839 return len;
840 }
841
842 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
843 {
844 kfree_skb(skb);
845 sock_put(sk);
846 }
847
848 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
849 {
850 int delta;
851
852 skb_orphan(skb);
853
854 delta = skb->end - skb->tail;
855 if (delta * 2 < skb->truesize)
856 return skb;
857
858 if (skb_shared(skb)) {
859 struct sk_buff *nskb = skb_clone(skb, allocation);
860 if (!nskb)
861 return skb;
862 kfree_skb(skb);
863 skb = nskb;
864 }
865
866 if (!pskb_expand_head(skb, 0, -delta, allocation))
867 skb->truesize -= delta;
868
869 return skb;
870 }
871
872 static void netlink_rcv_wake(struct sock *sk)
873 {
874 struct netlink_sock *nlk = nlk_sk(sk);
875
876 if (skb_queue_empty(&sk->sk_receive_queue))
877 clear_bit(0, &nlk->state);
878 if (!test_bit(0, &nlk->state))
879 wake_up_interruptible(&nlk->wait);
880 }
881
882 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb)
883 {
884 int ret;
885 struct netlink_sock *nlk = nlk_sk(sk);
886
887 ret = -ECONNREFUSED;
888 if (nlk->netlink_rcv != NULL) {
889 ret = skb->len;
890 skb_set_owner_r(skb, sk);
891 nlk->netlink_rcv(skb);
892 }
893 kfree_skb(skb);
894 sock_put(sk);
895 return ret;
896 }
897
898 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
899 u32 pid, int nonblock)
900 {
901 struct sock *sk;
902 int err;
903 long timeo;
904
905 skb = netlink_trim(skb, gfp_any());
906
907 timeo = sock_sndtimeo(ssk, nonblock);
908 retry:
909 sk = netlink_getsockbypid(ssk, pid);
910 if (IS_ERR(sk)) {
911 kfree_skb(skb);
912 return PTR_ERR(sk);
913 }
914 if (netlink_is_kernel(sk))
915 return netlink_unicast_kernel(sk, skb);
916
917 if (sk_filter(sk, skb)) {
918 err = skb->len;
919 kfree_skb(skb);
920 sock_put(sk);
921 return err;
922 }
923
924 err = netlink_attachskb(sk, skb, &timeo, ssk);
925 if (err == 1)
926 goto retry;
927 if (err)
928 return err;
929
930 return netlink_sendskb(sk, skb);
931 }
932 EXPORT_SYMBOL(netlink_unicast);
933
934 int netlink_has_listeners(struct sock *sk, unsigned int group)
935 {
936 int res = 0;
937 struct listeners *listeners;
938
939 BUG_ON(!netlink_is_kernel(sk));
940
941 rcu_read_lock();
942 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
943
944 if (group - 1 < nl_table[sk->sk_protocol].groups)
945 res = test_bit(group - 1, listeners->masks);
946
947 rcu_read_unlock();
948
949 return res;
950 }
951 EXPORT_SYMBOL_GPL(netlink_has_listeners);
952
953 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
954 {
955 struct netlink_sock *nlk = nlk_sk(sk);
956
957 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
958 !test_bit(0, &nlk->state)) {
959 skb_set_owner_r(skb, sk);
960 skb_queue_tail(&sk->sk_receive_queue, skb);
961 sk->sk_data_ready(sk, skb->len);
962 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
963 }
964 return -1;
965 }
966
967 struct netlink_broadcast_data {
968 struct sock *exclude_sk;
969 struct net *net;
970 u32 pid;
971 u32 group;
972 int failure;
973 int delivery_failure;
974 int congested;
975 int delivered;
976 gfp_t allocation;
977 struct sk_buff *skb, *skb2;
978 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
979 void *tx_data;
980 };
981
982 static int do_one_broadcast(struct sock *sk,
983 struct netlink_broadcast_data *p)
984 {
985 struct netlink_sock *nlk = nlk_sk(sk);
986 int val;
987
988 if (p->exclude_sk == sk)
989 goto out;
990
991 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
992 !test_bit(p->group - 1, nlk->groups))
993 goto out;
994
995 if (!net_eq(sock_net(sk), p->net))
996 goto out;
997
998 if (p->failure) {
999 netlink_overrun(sk);
1000 goto out;
1001 }
1002
1003 sock_hold(sk);
1004 if (p->skb2 == NULL) {
1005 if (skb_shared(p->skb)) {
1006 p->skb2 = skb_clone(p->skb, p->allocation);
1007 } else {
1008 p->skb2 = skb_get(p->skb);
1009 /*
1010 * skb ownership may have been set when
1011 * delivered to a previous socket.
1012 */
1013 skb_orphan(p->skb2);
1014 }
1015 }
1016 if (p->skb2 == NULL) {
1017 netlink_overrun(sk);
1018 /* Clone failed. Notify ALL listeners. */
1019 p->failure = 1;
1020 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1021 p->delivery_failure = 1;
1022 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1023 kfree_skb(p->skb2);
1024 p->skb2 = NULL;
1025 } else if (sk_filter(sk, p->skb2)) {
1026 kfree_skb(p->skb2);
1027 p->skb2 = NULL;
1028 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1029 netlink_overrun(sk);
1030 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1031 p->delivery_failure = 1;
1032 } else {
1033 p->congested |= val;
1034 p->delivered = 1;
1035 p->skb2 = NULL;
1036 }
1037 sock_put(sk);
1038
1039 out:
1040 return 0;
1041 }
1042
1043 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 pid,
1044 u32 group, gfp_t allocation,
1045 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1046 void *filter_data)
1047 {
1048 struct net *net = sock_net(ssk);
1049 struct netlink_broadcast_data info;
1050 struct hlist_node *node;
1051 struct sock *sk;
1052
1053 skb = netlink_trim(skb, allocation);
1054
1055 info.exclude_sk = ssk;
1056 info.net = net;
1057 info.pid = pid;
1058 info.group = group;
1059 info.failure = 0;
1060 info.delivery_failure = 0;
1061 info.congested = 0;
1062 info.delivered = 0;
1063 info.allocation = allocation;
1064 info.skb = skb;
1065 info.skb2 = NULL;
1066 info.tx_filter = filter;
1067 info.tx_data = filter_data;
1068
1069 /* While we sleep in clone, do not allow to change socket list */
1070
1071 netlink_lock_table();
1072
1073 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1074 do_one_broadcast(sk, &info);
1075
1076 consume_skb(skb);
1077
1078 netlink_unlock_table();
1079
1080 if (info.delivery_failure) {
1081 kfree_skb(info.skb2);
1082 return -ENOBUFS;
1083 } else
1084 consume_skb(info.skb2);
1085
1086 if (info.delivered) {
1087 if (info.congested && (allocation & __GFP_WAIT))
1088 yield();
1089 return 0;
1090 }
1091 return -ESRCH;
1092 }
1093 EXPORT_SYMBOL(netlink_broadcast_filtered);
1094
1095 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
1096 u32 group, gfp_t allocation)
1097 {
1098 return netlink_broadcast_filtered(ssk, skb, pid, group, allocation,
1099 NULL, NULL);
1100 }
1101 EXPORT_SYMBOL(netlink_broadcast);
1102
1103 struct netlink_set_err_data {
1104 struct sock *exclude_sk;
1105 u32 pid;
1106 u32 group;
1107 int code;
1108 };
1109
1110 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1111 {
1112 struct netlink_sock *nlk = nlk_sk(sk);
1113 int ret = 0;
1114
1115 if (sk == p->exclude_sk)
1116 goto out;
1117
1118 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1119 goto out;
1120
1121 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1122 !test_bit(p->group - 1, nlk->groups))
1123 goto out;
1124
1125 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
1126 ret = 1;
1127 goto out;
1128 }
1129
1130 sk->sk_err = p->code;
1131 sk->sk_error_report(sk);
1132 out:
1133 return ret;
1134 }
1135
1136 /**
1137 * netlink_set_err - report error to broadcast listeners
1138 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1139 * @pid: the PID of a process that we want to skip (if any)
1140 * @groups: the broadcast group that will notice the error
1141 * @code: error code, must be negative (as usual in kernelspace)
1142 *
1143 * This function returns the number of broadcast listeners that have set the
1144 * NETLINK_RECV_NO_ENOBUFS socket option.
1145 */
1146 int netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1147 {
1148 struct netlink_set_err_data info;
1149 struct hlist_node *node;
1150 struct sock *sk;
1151 int ret = 0;
1152
1153 info.exclude_sk = ssk;
1154 info.pid = pid;
1155 info.group = group;
1156 /* sk->sk_err wants a positive error value */
1157 info.code = -code;
1158
1159 read_lock(&nl_table_lock);
1160
1161 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1162 ret += do_one_set_err(sk, &info);
1163
1164 read_unlock(&nl_table_lock);
1165 return ret;
1166 }
1167 EXPORT_SYMBOL(netlink_set_err);
1168
1169 /* must be called with netlink table grabbed */
1170 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1171 unsigned int group,
1172 int is_new)
1173 {
1174 int old, new = !!is_new, subscriptions;
1175
1176 old = test_bit(group - 1, nlk->groups);
1177 subscriptions = nlk->subscriptions - old + new;
1178 if (new)
1179 __set_bit(group - 1, nlk->groups);
1180 else
1181 __clear_bit(group - 1, nlk->groups);
1182 netlink_update_subscriptions(&nlk->sk, subscriptions);
1183 netlink_update_listeners(&nlk->sk);
1184 }
1185
1186 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1187 char __user *optval, unsigned int optlen)
1188 {
1189 struct sock *sk = sock->sk;
1190 struct netlink_sock *nlk = nlk_sk(sk);
1191 unsigned int val = 0;
1192 int err;
1193
1194 if (level != SOL_NETLINK)
1195 return -ENOPROTOOPT;
1196
1197 if (optlen >= sizeof(int) &&
1198 get_user(val, (unsigned int __user *)optval))
1199 return -EFAULT;
1200
1201 switch (optname) {
1202 case NETLINK_PKTINFO:
1203 if (val)
1204 nlk->flags |= NETLINK_RECV_PKTINFO;
1205 else
1206 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1207 err = 0;
1208 break;
1209 case NETLINK_ADD_MEMBERSHIP:
1210 case NETLINK_DROP_MEMBERSHIP: {
1211 if (!netlink_capable(sock, NL_NONROOT_RECV))
1212 return -EPERM;
1213 err = netlink_realloc_groups(sk);
1214 if (err)
1215 return err;
1216 if (!val || val - 1 >= nlk->ngroups)
1217 return -EINVAL;
1218 netlink_table_grab();
1219 netlink_update_socket_mc(nlk, val,
1220 optname == NETLINK_ADD_MEMBERSHIP);
1221 netlink_table_ungrab();
1222 err = 0;
1223 break;
1224 }
1225 case NETLINK_BROADCAST_ERROR:
1226 if (val)
1227 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1228 else
1229 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1230 err = 0;
1231 break;
1232 case NETLINK_NO_ENOBUFS:
1233 if (val) {
1234 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1235 clear_bit(0, &nlk->state);
1236 wake_up_interruptible(&nlk->wait);
1237 } else
1238 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1239 err = 0;
1240 break;
1241 default:
1242 err = -ENOPROTOOPT;
1243 }
1244 return err;
1245 }
1246
1247 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1248 char __user *optval, int __user *optlen)
1249 {
1250 struct sock *sk = sock->sk;
1251 struct netlink_sock *nlk = nlk_sk(sk);
1252 int len, val, err;
1253
1254 if (level != SOL_NETLINK)
1255 return -ENOPROTOOPT;
1256
1257 if (get_user(len, optlen))
1258 return -EFAULT;
1259 if (len < 0)
1260 return -EINVAL;
1261
1262 switch (optname) {
1263 case NETLINK_PKTINFO:
1264 if (len < sizeof(int))
1265 return -EINVAL;
1266 len = sizeof(int);
1267 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1268 if (put_user(len, optlen) ||
1269 put_user(val, optval))
1270 return -EFAULT;
1271 err = 0;
1272 break;
1273 case NETLINK_BROADCAST_ERROR:
1274 if (len < sizeof(int))
1275 return -EINVAL;
1276 len = sizeof(int);
1277 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1278 if (put_user(len, optlen) ||
1279 put_user(val, optval))
1280 return -EFAULT;
1281 err = 0;
1282 break;
1283 case NETLINK_NO_ENOBUFS:
1284 if (len < sizeof(int))
1285 return -EINVAL;
1286 len = sizeof(int);
1287 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1288 if (put_user(len, optlen) ||
1289 put_user(val, optval))
1290 return -EFAULT;
1291 err = 0;
1292 break;
1293 default:
1294 err = -ENOPROTOOPT;
1295 }
1296 return err;
1297 }
1298
1299 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1300 {
1301 struct nl_pktinfo info;
1302
1303 info.group = NETLINK_CB(skb).dst_group;
1304 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1305 }
1306
1307 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1308 struct msghdr *msg, size_t len)
1309 {
1310 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1311 struct sock *sk = sock->sk;
1312 struct netlink_sock *nlk = nlk_sk(sk);
1313 struct sockaddr_nl *addr = msg->msg_name;
1314 u32 dst_pid;
1315 u32 dst_group;
1316 struct sk_buff *skb;
1317 int err;
1318 struct scm_cookie scm;
1319
1320 if (msg->msg_flags&MSG_OOB)
1321 return -EOPNOTSUPP;
1322
1323 if (NULL == siocb->scm)
1324 siocb->scm = &scm;
1325
1326 err = scm_send(sock, msg, siocb->scm);
1327 if (err < 0)
1328 return err;
1329
1330 if (msg->msg_namelen) {
1331 err = -EINVAL;
1332 if (addr->nl_family != AF_NETLINK)
1333 goto out;
1334 dst_pid = addr->nl_pid;
1335 dst_group = ffs(addr->nl_groups);
1336 err = -EPERM;
1337 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1338 goto out;
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 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1361
1362 err = -EFAULT;
1363 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1364 kfree_skb(skb);
1365 goto out;
1366 }
1367
1368 err = security_netlink_send(sk, skb);
1369 if (err) {
1370 kfree_skb(skb);
1371 goto out;
1372 }
1373
1374 if (dst_group) {
1375 atomic_inc(&skb->users);
1376 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1377 }
1378 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1379
1380 out:
1381 scm_destroy(siocb->scm);
1382 return err;
1383 }
1384
1385 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1386 struct msghdr *msg, size_t len,
1387 int flags)
1388 {
1389 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1390 struct scm_cookie scm;
1391 struct sock *sk = sock->sk;
1392 struct netlink_sock *nlk = nlk_sk(sk);
1393 int noblock = flags&MSG_DONTWAIT;
1394 size_t copied;
1395 struct sk_buff *skb, *data_skb;
1396 int err, ret;
1397
1398 if (flags&MSG_OOB)
1399 return -EOPNOTSUPP;
1400
1401 copied = 0;
1402
1403 skb = skb_recv_datagram(sk, flags, noblock, &err);
1404 if (skb == NULL)
1405 goto out;
1406
1407 data_skb = skb;
1408
1409 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1410 if (unlikely(skb_shinfo(skb)->frag_list)) {
1411 /*
1412 * If this skb has a frag_list, then here that means that we
1413 * will have to use the frag_list skb's data for compat tasks
1414 * and the regular skb's data for normal (non-compat) tasks.
1415 *
1416 * If we need to send the compat skb, assign it to the
1417 * 'data_skb' variable so that it will be used below for data
1418 * copying. We keep 'skb' for everything else, including
1419 * freeing both later.
1420 */
1421 if (flags & MSG_CMSG_COMPAT)
1422 data_skb = skb_shinfo(skb)->frag_list;
1423 }
1424 #endif
1425
1426 msg->msg_namelen = 0;
1427
1428 copied = data_skb->len;
1429 if (len < copied) {
1430 msg->msg_flags |= MSG_TRUNC;
1431 copied = len;
1432 }
1433
1434 skb_reset_transport_header(data_skb);
1435 err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
1436
1437 if (msg->msg_name) {
1438 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1439 addr->nl_family = AF_NETLINK;
1440 addr->nl_pad = 0;
1441 addr->nl_pid = NETLINK_CB(skb).pid;
1442 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1443 msg->msg_namelen = sizeof(*addr);
1444 }
1445
1446 if (nlk->flags & NETLINK_RECV_PKTINFO)
1447 netlink_cmsg_recv_pktinfo(msg, skb);
1448
1449 if (NULL == siocb->scm) {
1450 memset(&scm, 0, sizeof(scm));
1451 siocb->scm = &scm;
1452 }
1453 siocb->scm->creds = *NETLINK_CREDS(skb);
1454 if (flags & MSG_TRUNC)
1455 copied = data_skb->len;
1456
1457 skb_free_datagram(sk, skb);
1458
1459 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1460 ret = netlink_dump(sk);
1461 if (ret) {
1462 sk->sk_err = ret;
1463 sk->sk_error_report(sk);
1464 }
1465 }
1466
1467 scm_recv(sock, msg, siocb->scm, flags);
1468 out:
1469 netlink_rcv_wake(sk);
1470 return err ? : copied;
1471 }
1472
1473 static void netlink_data_ready(struct sock *sk, int len)
1474 {
1475 BUG();
1476 }
1477
1478 /*
1479 * We export these functions to other modules. They provide a
1480 * complete set of kernel non-blocking support for message
1481 * queueing.
1482 */
1483
1484 struct sock *
1485 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1486 void (*input)(struct sk_buff *skb),
1487 struct mutex *cb_mutex, struct module *module)
1488 {
1489 struct socket *sock;
1490 struct sock *sk;
1491 struct netlink_sock *nlk;
1492 struct listeners *listeners = NULL;
1493
1494 BUG_ON(!nl_table);
1495
1496 if (unit < 0 || unit >= MAX_LINKS)
1497 return NULL;
1498
1499 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1500 return NULL;
1501
1502 /*
1503 * We have to just have a reference on the net from sk, but don't
1504 * get_net it. Besides, we cannot get and then put the net here.
1505 * So we create one inside init_net and the move it to net.
1506 */
1507
1508 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1509 goto out_sock_release_nosk;
1510
1511 sk = sock->sk;
1512 sk_change_net(sk, net);
1513
1514 if (groups < 32)
1515 groups = 32;
1516
1517 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
1518 if (!listeners)
1519 goto out_sock_release;
1520
1521 sk->sk_data_ready = netlink_data_ready;
1522 if (input)
1523 nlk_sk(sk)->netlink_rcv = input;
1524
1525 if (netlink_insert(sk, net, 0))
1526 goto out_sock_release;
1527
1528 nlk = nlk_sk(sk);
1529 nlk->flags |= NETLINK_KERNEL_SOCKET;
1530
1531 netlink_table_grab();
1532 if (!nl_table[unit].registered) {
1533 nl_table[unit].groups = groups;
1534 rcu_assign_pointer(nl_table[unit].listeners, listeners);
1535 nl_table[unit].cb_mutex = cb_mutex;
1536 nl_table[unit].module = module;
1537 nl_table[unit].registered = 1;
1538 } else {
1539 kfree(listeners);
1540 nl_table[unit].registered++;
1541 }
1542 netlink_table_ungrab();
1543 return sk;
1544
1545 out_sock_release:
1546 kfree(listeners);
1547 netlink_kernel_release(sk);
1548 return NULL;
1549
1550 out_sock_release_nosk:
1551 sock_release(sock);
1552 return NULL;
1553 }
1554 EXPORT_SYMBOL(netlink_kernel_create);
1555
1556
1557 void
1558 netlink_kernel_release(struct sock *sk)
1559 {
1560 sk_release_kernel(sk);
1561 }
1562 EXPORT_SYMBOL(netlink_kernel_release);
1563
1564 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1565 {
1566 struct listeners *new, *old;
1567 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1568
1569 if (groups < 32)
1570 groups = 32;
1571
1572 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1573 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
1574 if (!new)
1575 return -ENOMEM;
1576 old = rcu_dereference_protected(tbl->listeners, 1);
1577 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
1578 rcu_assign_pointer(tbl->listeners, new);
1579
1580 kfree_rcu(old, rcu);
1581 }
1582 tbl->groups = groups;
1583
1584 return 0;
1585 }
1586
1587 /**
1588 * netlink_change_ngroups - change number of multicast groups
1589 *
1590 * This changes the number of multicast groups that are available
1591 * on a certain netlink family. Note that it is not possible to
1592 * change the number of groups to below 32. Also note that it does
1593 * not implicitly call netlink_clear_multicast_users() when the
1594 * number of groups is reduced.
1595 *
1596 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1597 * @groups: The new number of groups.
1598 */
1599 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1600 {
1601 int err;
1602
1603 netlink_table_grab();
1604 err = __netlink_change_ngroups(sk, groups);
1605 netlink_table_ungrab();
1606
1607 return err;
1608 }
1609
1610 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1611 {
1612 struct sock *sk;
1613 struct hlist_node *node;
1614 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1615
1616 sk_for_each_bound(sk, node, &tbl->mc_list)
1617 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1618 }
1619
1620 /**
1621 * netlink_clear_multicast_users - kick off multicast listeners
1622 *
1623 * This function removes all listeners from the given group.
1624 * @ksk: The kernel netlink socket, as returned by
1625 * netlink_kernel_create().
1626 * @group: The multicast group to clear.
1627 */
1628 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1629 {
1630 netlink_table_grab();
1631 __netlink_clear_multicast_users(ksk, group);
1632 netlink_table_ungrab();
1633 }
1634
1635 void netlink_set_nonroot(int protocol, unsigned int flags)
1636 {
1637 if ((unsigned int)protocol < MAX_LINKS)
1638 nl_table[protocol].nl_nonroot = flags;
1639 }
1640 EXPORT_SYMBOL(netlink_set_nonroot);
1641
1642 static void netlink_destroy_callback(struct netlink_callback *cb)
1643 {
1644 kfree_skb(cb->skb);
1645 kfree(cb);
1646 }
1647
1648 /*
1649 * It looks a bit ugly.
1650 * It would be better to create kernel thread.
1651 */
1652
1653 static int netlink_dump(struct sock *sk)
1654 {
1655 struct netlink_sock *nlk = nlk_sk(sk);
1656 struct netlink_callback *cb;
1657 struct sk_buff *skb = NULL;
1658 struct nlmsghdr *nlh;
1659 int len, err = -ENOBUFS;
1660 int alloc_size;
1661
1662 mutex_lock(nlk->cb_mutex);
1663
1664 cb = nlk->cb;
1665 if (cb == NULL) {
1666 err = -EINVAL;
1667 goto errout_skb;
1668 }
1669
1670 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
1671
1672 skb = sock_rmalloc(sk, alloc_size, 0, GFP_KERNEL);
1673 if (!skb)
1674 goto errout_skb;
1675
1676 len = cb->dump(skb, cb);
1677
1678 if (len > 0) {
1679 mutex_unlock(nlk->cb_mutex);
1680
1681 if (sk_filter(sk, skb))
1682 kfree_skb(skb);
1683 else {
1684 skb_queue_tail(&sk->sk_receive_queue, skb);
1685 sk->sk_data_ready(sk, skb->len);
1686 }
1687 return 0;
1688 }
1689
1690 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1691 if (!nlh)
1692 goto errout_skb;
1693
1694 nl_dump_check_consistent(cb, nlh);
1695
1696 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1697
1698 if (sk_filter(sk, skb))
1699 kfree_skb(skb);
1700 else {
1701 skb_queue_tail(&sk->sk_receive_queue, skb);
1702 sk->sk_data_ready(sk, skb->len);
1703 }
1704
1705 if (cb->done)
1706 cb->done(cb);
1707 nlk->cb = NULL;
1708 mutex_unlock(nlk->cb_mutex);
1709
1710 netlink_destroy_callback(cb);
1711 return 0;
1712
1713 errout_skb:
1714 mutex_unlock(nlk->cb_mutex);
1715 kfree_skb(skb);
1716 return err;
1717 }
1718
1719 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1720 const struct nlmsghdr *nlh,
1721 int (*dump)(struct sk_buff *skb,
1722 struct netlink_callback *),
1723 int (*done)(struct netlink_callback *),
1724 u16 min_dump_alloc)
1725 {
1726 struct netlink_callback *cb;
1727 struct sock *sk;
1728 struct netlink_sock *nlk;
1729 int ret;
1730
1731 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1732 if (cb == NULL)
1733 return -ENOBUFS;
1734
1735 cb->dump = dump;
1736 cb->done = done;
1737 cb->nlh = nlh;
1738 cb->min_dump_alloc = min_dump_alloc;
1739 atomic_inc(&skb->users);
1740 cb->skb = skb;
1741
1742 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1743 if (sk == NULL) {
1744 netlink_destroy_callback(cb);
1745 return -ECONNREFUSED;
1746 }
1747 nlk = nlk_sk(sk);
1748 /* A dump is in progress... */
1749 mutex_lock(nlk->cb_mutex);
1750 if (nlk->cb) {
1751 mutex_unlock(nlk->cb_mutex);
1752 netlink_destroy_callback(cb);
1753 sock_put(sk);
1754 return -EBUSY;
1755 }
1756 nlk->cb = cb;
1757 mutex_unlock(nlk->cb_mutex);
1758
1759 ret = netlink_dump(sk);
1760
1761 sock_put(sk);
1762
1763 if (ret)
1764 return ret;
1765
1766 /* We successfully started a dump, by returning -EINTR we
1767 * signal not to send ACK even if it was requested.
1768 */
1769 return -EINTR;
1770 }
1771 EXPORT_SYMBOL(netlink_dump_start);
1772
1773 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1774 {
1775 struct sk_buff *skb;
1776 struct nlmsghdr *rep;
1777 struct nlmsgerr *errmsg;
1778 size_t payload = sizeof(*errmsg);
1779
1780 /* error messages get the original request appened */
1781 if (err)
1782 payload += nlmsg_len(nlh);
1783
1784 skb = nlmsg_new(payload, GFP_KERNEL);
1785 if (!skb) {
1786 struct sock *sk;
1787
1788 sk = netlink_lookup(sock_net(in_skb->sk),
1789 in_skb->sk->sk_protocol,
1790 NETLINK_CB(in_skb).pid);
1791 if (sk) {
1792 sk->sk_err = ENOBUFS;
1793 sk->sk_error_report(sk);
1794 sock_put(sk);
1795 }
1796 return;
1797 }
1798
1799 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1800 NLMSG_ERROR, payload, 0);
1801 errmsg = nlmsg_data(rep);
1802 errmsg->error = err;
1803 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1804 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1805 }
1806 EXPORT_SYMBOL(netlink_ack);
1807
1808 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1809 struct nlmsghdr *))
1810 {
1811 struct nlmsghdr *nlh;
1812 int err;
1813
1814 while (skb->len >= nlmsg_total_size(0)) {
1815 int msglen;
1816
1817 nlh = nlmsg_hdr(skb);
1818 err = 0;
1819
1820 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1821 return 0;
1822
1823 /* Only requests are handled by the kernel */
1824 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1825 goto ack;
1826
1827 /* Skip control messages */
1828 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1829 goto ack;
1830
1831 err = cb(skb, nlh);
1832 if (err == -EINTR)
1833 goto skip;
1834
1835 ack:
1836 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1837 netlink_ack(skb, nlh, err);
1838
1839 skip:
1840 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1841 if (msglen > skb->len)
1842 msglen = skb->len;
1843 skb_pull(skb, msglen);
1844 }
1845
1846 return 0;
1847 }
1848 EXPORT_SYMBOL(netlink_rcv_skb);
1849
1850 /**
1851 * nlmsg_notify - send a notification netlink message
1852 * @sk: netlink socket to use
1853 * @skb: notification message
1854 * @pid: destination netlink pid for reports or 0
1855 * @group: destination multicast group or 0
1856 * @report: 1 to report back, 0 to disable
1857 * @flags: allocation flags
1858 */
1859 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1860 unsigned int group, int report, gfp_t flags)
1861 {
1862 int err = 0;
1863
1864 if (group) {
1865 int exclude_pid = 0;
1866
1867 if (report) {
1868 atomic_inc(&skb->users);
1869 exclude_pid = pid;
1870 }
1871
1872 /* errors reported via destination sk->sk_err, but propagate
1873 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1874 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1875 }
1876
1877 if (report) {
1878 int err2;
1879
1880 err2 = nlmsg_unicast(sk, skb, pid);
1881 if (!err || err == -ESRCH)
1882 err = err2;
1883 }
1884
1885 return err;
1886 }
1887 EXPORT_SYMBOL(nlmsg_notify);
1888
1889 #ifdef CONFIG_PROC_FS
1890 struct nl_seq_iter {
1891 struct seq_net_private p;
1892 int link;
1893 int hash_idx;
1894 };
1895
1896 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1897 {
1898 struct nl_seq_iter *iter = seq->private;
1899 int i, j;
1900 struct sock *s;
1901 struct hlist_node *node;
1902 loff_t off = 0;
1903
1904 for (i = 0; i < MAX_LINKS; i++) {
1905 struct nl_pid_hash *hash = &nl_table[i].hash;
1906
1907 for (j = 0; j <= hash->mask; j++) {
1908 sk_for_each(s, node, &hash->table[j]) {
1909 if (sock_net(s) != seq_file_net(seq))
1910 continue;
1911 if (off == pos) {
1912 iter->link = i;
1913 iter->hash_idx = j;
1914 return s;
1915 }
1916 ++off;
1917 }
1918 }
1919 }
1920 return NULL;
1921 }
1922
1923 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1924 __acquires(nl_table_lock)
1925 {
1926 read_lock(&nl_table_lock);
1927 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1928 }
1929
1930 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1931 {
1932 struct sock *s;
1933 struct nl_seq_iter *iter;
1934 int i, j;
1935
1936 ++*pos;
1937
1938 if (v == SEQ_START_TOKEN)
1939 return netlink_seq_socket_idx(seq, 0);
1940
1941 iter = seq->private;
1942 s = v;
1943 do {
1944 s = sk_next(s);
1945 } while (s && sock_net(s) != seq_file_net(seq));
1946 if (s)
1947 return s;
1948
1949 i = iter->link;
1950 j = iter->hash_idx + 1;
1951
1952 do {
1953 struct nl_pid_hash *hash = &nl_table[i].hash;
1954
1955 for (; j <= hash->mask; j++) {
1956 s = sk_head(&hash->table[j]);
1957 while (s && sock_net(s) != seq_file_net(seq))
1958 s = sk_next(s);
1959 if (s) {
1960 iter->link = i;
1961 iter->hash_idx = j;
1962 return s;
1963 }
1964 }
1965
1966 j = 0;
1967 } while (++i < MAX_LINKS);
1968
1969 return NULL;
1970 }
1971
1972 static void netlink_seq_stop(struct seq_file *seq, void *v)
1973 __releases(nl_table_lock)
1974 {
1975 read_unlock(&nl_table_lock);
1976 }
1977
1978
1979 static int netlink_seq_show(struct seq_file *seq, void *v)
1980 {
1981 if (v == SEQ_START_TOKEN)
1982 seq_puts(seq,
1983 "sk Eth Pid Groups "
1984 "Rmem Wmem Dump Locks Drops Inode\n");
1985 else {
1986 struct sock *s = v;
1987 struct netlink_sock *nlk = nlk_sk(s);
1988
1989 seq_printf(seq, "%pK %-3d %-6d %08x %-8d %-8d %pK %-8d %-8d %-8lu\n",
1990 s,
1991 s->sk_protocol,
1992 nlk->pid,
1993 nlk->groups ? (u32)nlk->groups[0] : 0,
1994 sk_rmem_alloc_get(s),
1995 sk_wmem_alloc_get(s),
1996 nlk->cb,
1997 atomic_read(&s->sk_refcnt),
1998 atomic_read(&s->sk_drops),
1999 sock_i_ino(s)
2000 );
2001
2002 }
2003 return 0;
2004 }
2005
2006 static const struct seq_operations netlink_seq_ops = {
2007 .start = netlink_seq_start,
2008 .next = netlink_seq_next,
2009 .stop = netlink_seq_stop,
2010 .show = netlink_seq_show,
2011 };
2012
2013
2014 static int netlink_seq_open(struct inode *inode, struct file *file)
2015 {
2016 return seq_open_net(inode, file, &netlink_seq_ops,
2017 sizeof(struct nl_seq_iter));
2018 }
2019
2020 static const struct file_operations netlink_seq_fops = {
2021 .owner = THIS_MODULE,
2022 .open = netlink_seq_open,
2023 .read = seq_read,
2024 .llseek = seq_lseek,
2025 .release = seq_release_net,
2026 };
2027
2028 #endif
2029
2030 int netlink_register_notifier(struct notifier_block *nb)
2031 {
2032 return atomic_notifier_chain_register(&netlink_chain, nb);
2033 }
2034 EXPORT_SYMBOL(netlink_register_notifier);
2035
2036 int netlink_unregister_notifier(struct notifier_block *nb)
2037 {
2038 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2039 }
2040 EXPORT_SYMBOL(netlink_unregister_notifier);
2041
2042 static const struct proto_ops netlink_ops = {
2043 .family = PF_NETLINK,
2044 .owner = THIS_MODULE,
2045 .release = netlink_release,
2046 .bind = netlink_bind,
2047 .connect = netlink_connect,
2048 .socketpair = sock_no_socketpair,
2049 .accept = sock_no_accept,
2050 .getname = netlink_getname,
2051 .poll = datagram_poll,
2052 .ioctl = sock_no_ioctl,
2053 .listen = sock_no_listen,
2054 .shutdown = sock_no_shutdown,
2055 .setsockopt = netlink_setsockopt,
2056 .getsockopt = netlink_getsockopt,
2057 .sendmsg = netlink_sendmsg,
2058 .recvmsg = netlink_recvmsg,
2059 .mmap = sock_no_mmap,
2060 .sendpage = sock_no_sendpage,
2061 };
2062
2063 static const struct net_proto_family netlink_family_ops = {
2064 .family = PF_NETLINK,
2065 .create = netlink_create,
2066 .owner = THIS_MODULE, /* for consistency 8) */
2067 };
2068
2069 static int __net_init netlink_net_init(struct net *net)
2070 {
2071 #ifdef CONFIG_PROC_FS
2072 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2073 return -ENOMEM;
2074 #endif
2075 return 0;
2076 }
2077
2078 static void __net_exit netlink_net_exit(struct net *net)
2079 {
2080 #ifdef CONFIG_PROC_FS
2081 proc_net_remove(net, "netlink");
2082 #endif
2083 }
2084
2085 static void __init netlink_add_usersock_entry(void)
2086 {
2087 struct listeners *listeners;
2088 int groups = 32;
2089
2090 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2091 if (!listeners)
2092 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2093
2094 netlink_table_grab();
2095
2096 nl_table[NETLINK_USERSOCK].groups = groups;
2097 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2098 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2099 nl_table[NETLINK_USERSOCK].registered = 1;
2100
2101 netlink_table_ungrab();
2102 }
2103
2104 static struct pernet_operations __net_initdata netlink_net_ops = {
2105 .init = netlink_net_init,
2106 .exit = netlink_net_exit,
2107 };
2108
2109 static int __init netlink_proto_init(void)
2110 {
2111 struct sk_buff *dummy_skb;
2112 int i;
2113 unsigned long limit;
2114 unsigned int order;
2115 int err = proto_register(&netlink_proto, 0);
2116
2117 if (err != 0)
2118 goto out;
2119
2120 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2121
2122 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2123 if (!nl_table)
2124 goto panic;
2125
2126 if (totalram_pages >= (128 * 1024))
2127 limit = totalram_pages >> (21 - PAGE_SHIFT);
2128 else
2129 limit = totalram_pages >> (23 - PAGE_SHIFT);
2130
2131 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2132 limit = (1UL << order) / sizeof(struct hlist_head);
2133 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2134
2135 for (i = 0; i < MAX_LINKS; i++) {
2136 struct nl_pid_hash *hash = &nl_table[i].hash;
2137
2138 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
2139 if (!hash->table) {
2140 while (i-- > 0)
2141 nl_pid_hash_free(nl_table[i].hash.table,
2142 1 * sizeof(*hash->table));
2143 kfree(nl_table);
2144 goto panic;
2145 }
2146 hash->max_shift = order;
2147 hash->shift = 0;
2148 hash->mask = 0;
2149 hash->rehash_time = jiffies;
2150 }
2151
2152 netlink_add_usersock_entry();
2153
2154 sock_register(&netlink_family_ops);
2155 register_pernet_subsys(&netlink_net_ops);
2156 /* The netlink device handler may be needed early. */
2157 rtnetlink_init();
2158 out:
2159 return err;
2160 panic:
2161 panic("netlink_init: Cannot allocate nl_table\n");
2162 }
2163
2164 core_initcall(netlink_proto_init);
Linux kernel - Deliverables
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