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Merge branch 'v6v7' into devel
[linux/fpc-iii.git] / net / netlink / af_netlink.c
blob1f924595bdefd8e6f632563b29aebf670c566869
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 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->masks[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 struct listeners *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->masks);
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 consume_skb(skb);
1080
1081 netlink_unlock_table();
1082
1083 if (info.delivery_failure) {
1084 kfree_skb(info.skb2);
1085 return -ENOBUFS;
1086 } else
1087 consume_skb(info.skb2);
1088
1089 if (info.delivered) {
1090 if (info.congested && (allocation & __GFP_WAIT))
1091 yield();
1092 return 0;
1093 }
1094 return -ESRCH;
1095 }
1096 EXPORT_SYMBOL(netlink_broadcast_filtered);
1097
1098 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
1099 u32 group, gfp_t allocation)
1100 {
1101 return netlink_broadcast_filtered(ssk, skb, pid, group, allocation,
1102 NULL, NULL);
1103 }
1104 EXPORT_SYMBOL(netlink_broadcast);
1105
1106 struct netlink_set_err_data {
1107 struct sock *exclude_sk;
1108 u32 pid;
1109 u32 group;
1110 int code;
1111 };
1112
1113 static inline int do_one_set_err(struct sock *sk,
1114 struct netlink_set_err_data *p)
1115 {
1116 struct netlink_sock *nlk = nlk_sk(sk);
1117 int ret = 0;
1118
1119 if (sk == p->exclude_sk)
1120 goto out;
1121
1122 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1123 goto out;
1124
1125 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1126 !test_bit(p->group - 1, nlk->groups))
1127 goto out;
1128
1129 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
1130 ret = 1;
1131 goto out;
1132 }
1133
1134 sk->sk_err = p->code;
1135 sk->sk_error_report(sk);
1136 out:
1137 return ret;
1138 }
1139
1140 /**
1141 * netlink_set_err - report error to broadcast listeners
1142 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1143 * @pid: the PID of a process that we want to skip (if any)
1144 * @groups: the broadcast group that will notice the error
1145 * @code: error code, must be negative (as usual in kernelspace)
1146 *
1147 * This function returns the number of broadcast listeners that have set the
1148 * NETLINK_RECV_NO_ENOBUFS socket option.
1149 */
1150 int netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1151 {
1152 struct netlink_set_err_data info;
1153 struct hlist_node *node;
1154 struct sock *sk;
1155 int ret = 0;
1156
1157 info.exclude_sk = ssk;
1158 info.pid = pid;
1159 info.group = group;
1160 /* sk->sk_err wants a positive error value */
1161 info.code = -code;
1162
1163 read_lock(&nl_table_lock);
1164
1165 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1166 ret += do_one_set_err(sk, &info);
1167
1168 read_unlock(&nl_table_lock);
1169 return ret;
1170 }
1171 EXPORT_SYMBOL(netlink_set_err);
1172
1173 /* must be called with netlink table grabbed */
1174 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1175 unsigned int group,
1176 int is_new)
1177 {
1178 int old, new = !!is_new, subscriptions;
1179
1180 old = test_bit(group - 1, nlk->groups);
1181 subscriptions = nlk->subscriptions - old + new;
1182 if (new)
1183 __set_bit(group - 1, nlk->groups);
1184 else
1185 __clear_bit(group - 1, nlk->groups);
1186 netlink_update_subscriptions(&nlk->sk, subscriptions);
1187 netlink_update_listeners(&nlk->sk);
1188 }
1189
1190 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1191 char __user *optval, unsigned int optlen)
1192 {
1193 struct sock *sk = sock->sk;
1194 struct netlink_sock *nlk = nlk_sk(sk);
1195 unsigned int val = 0;
1196 int err;
1197
1198 if (level != SOL_NETLINK)
1199 return -ENOPROTOOPT;
1200
1201 if (optlen >= sizeof(int) &&
1202 get_user(val, (unsigned int __user *)optval))
1203 return -EFAULT;
1204
1205 switch (optname) {
1206 case NETLINK_PKTINFO:
1207 if (val)
1208 nlk->flags |= NETLINK_RECV_PKTINFO;
1209 else
1210 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1211 err = 0;
1212 break;
1213 case NETLINK_ADD_MEMBERSHIP:
1214 case NETLINK_DROP_MEMBERSHIP: {
1215 if (!netlink_capable(sock, NL_NONROOT_RECV))
1216 return -EPERM;
1217 err = netlink_realloc_groups(sk);
1218 if (err)
1219 return err;
1220 if (!val || val - 1 >= nlk->ngroups)
1221 return -EINVAL;
1222 netlink_table_grab();
1223 netlink_update_socket_mc(nlk, val,
1224 optname == NETLINK_ADD_MEMBERSHIP);
1225 netlink_table_ungrab();
1226 err = 0;
1227 break;
1228 }
1229 case NETLINK_BROADCAST_ERROR:
1230 if (val)
1231 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1232 else
1233 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1234 err = 0;
1235 break;
1236 case NETLINK_NO_ENOBUFS:
1237 if (val) {
1238 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1239 clear_bit(0, &nlk->state);
1240 wake_up_interruptible(&nlk->wait);
1241 } else
1242 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1243 err = 0;
1244 break;
1245 default:
1246 err = -ENOPROTOOPT;
1247 }
1248 return err;
1249 }
1250
1251 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1252 char __user *optval, int __user *optlen)
1253 {
1254 struct sock *sk = sock->sk;
1255 struct netlink_sock *nlk = nlk_sk(sk);
1256 int len, val, err;
1257
1258 if (level != SOL_NETLINK)
1259 return -ENOPROTOOPT;
1260
1261 if (get_user(len, optlen))
1262 return -EFAULT;
1263 if (len < 0)
1264 return -EINVAL;
1265
1266 switch (optname) {
1267 case NETLINK_PKTINFO:
1268 if (len < sizeof(int))
1269 return -EINVAL;
1270 len = sizeof(int);
1271 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1272 if (put_user(len, optlen) ||
1273 put_user(val, optval))
1274 return -EFAULT;
1275 err = 0;
1276 break;
1277 case NETLINK_BROADCAST_ERROR:
1278 if (len < sizeof(int))
1279 return -EINVAL;
1280 len = sizeof(int);
1281 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1282 if (put_user(len, optlen) ||
1283 put_user(val, optval))
1284 return -EFAULT;
1285 err = 0;
1286 break;
1287 case NETLINK_NO_ENOBUFS:
1288 if (len < sizeof(int))
1289 return -EINVAL;
1290 len = sizeof(int);
1291 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1292 if (put_user(len, optlen) ||
1293 put_user(val, optval))
1294 return -EFAULT;
1295 err = 0;
1296 break;
1297 default:
1298 err = -ENOPROTOOPT;
1299 }
1300 return err;
1301 }
1302
1303 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1304 {
1305 struct nl_pktinfo info;
1306
1307 info.group = NETLINK_CB(skb).dst_group;
1308 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1309 }
1310
1311 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1312 struct msghdr *msg, size_t len)
1313 {
1314 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1315 struct sock *sk = sock->sk;
1316 struct netlink_sock *nlk = nlk_sk(sk);
1317 struct sockaddr_nl *addr = msg->msg_name;
1318 u32 dst_pid;
1319 u32 dst_group;
1320 struct sk_buff *skb;
1321 int err;
1322 struct scm_cookie scm;
1323
1324 if (msg->msg_flags&MSG_OOB)
1325 return -EOPNOTSUPP;
1326
1327 if (NULL == siocb->scm) {
1328 siocb->scm = &scm;
1329 memset(&scm, 0, sizeof(scm));
1330 }
1331 err = scm_send(sock, msg, siocb->scm);
1332 if (err < 0)
1333 return err;
1334
1335 if (msg->msg_namelen) {
1336 err = -EINVAL;
1337 if (addr->nl_family != AF_NETLINK)
1338 goto out;
1339 dst_pid = addr->nl_pid;
1340 dst_group = ffs(addr->nl_groups);
1341 err = -EPERM;
1342 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1343 goto out;
1344 } else {
1345 dst_pid = nlk->dst_pid;
1346 dst_group = nlk->dst_group;
1347 }
1348
1349 if (!nlk->pid) {
1350 err = netlink_autobind(sock);
1351 if (err)
1352 goto out;
1353 }
1354
1355 err = -EMSGSIZE;
1356 if (len > sk->sk_sndbuf - 32)
1357 goto out;
1358 err = -ENOBUFS;
1359 skb = alloc_skb(len, GFP_KERNEL);
1360 if (skb == NULL)
1361 goto out;
1362
1363 NETLINK_CB(skb).pid = nlk->pid;
1364 NETLINK_CB(skb).dst_group = dst_group;
1365 NETLINK_CB(skb).loginuid = audit_get_loginuid(current);
1366 NETLINK_CB(skb).sessionid = audit_get_sessionid(current);
1367 security_task_getsecid(current, &(NETLINK_CB(skb).sid));
1368 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1369
1370 /* What can I do? Netlink is asynchronous, so that
1371 we will have to save current capabilities to
1372 check them, when this message will be delivered
1373 to corresponding kernel module. --ANK (980802)
1374 */
1375
1376 err = -EFAULT;
1377 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1378 kfree_skb(skb);
1379 goto out;
1380 }
1381
1382 err = security_netlink_send(sk, skb);
1383 if (err) {
1384 kfree_skb(skb);
1385 goto out;
1386 }
1387
1388 if (dst_group) {
1389 atomic_inc(&skb->users);
1390 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1391 }
1392 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1393
1394 out:
1395 scm_destroy(siocb->scm);
1396 return err;
1397 }
1398
1399 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1400 struct msghdr *msg, size_t len,
1401 int flags)
1402 {
1403 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1404 struct scm_cookie scm;
1405 struct sock *sk = sock->sk;
1406 struct netlink_sock *nlk = nlk_sk(sk);
1407 int noblock = flags&MSG_DONTWAIT;
1408 size_t copied;
1409 struct sk_buff *skb, *data_skb;
1410 int err, ret;
1411
1412 if (flags&MSG_OOB)
1413 return -EOPNOTSUPP;
1414
1415 copied = 0;
1416
1417 skb = skb_recv_datagram(sk, flags, noblock, &err);
1418 if (skb == NULL)
1419 goto out;
1420
1421 data_skb = skb;
1422
1423 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1424 if (unlikely(skb_shinfo(skb)->frag_list)) {
1425 /*
1426 * If this skb has a frag_list, then here that means that we
1427 * will have to use the frag_list skb's data for compat tasks
1428 * and the regular skb's data for normal (non-compat) tasks.
1429 *
1430 * If we need to send the compat skb, assign it to the
1431 * 'data_skb' variable so that it will be used below for data
1432 * copying. We keep 'skb' for everything else, including
1433 * freeing both later.
1434 */
1435 if (flags & MSG_CMSG_COMPAT)
1436 data_skb = skb_shinfo(skb)->frag_list;
1437 }
1438 #endif
1439
1440 msg->msg_namelen = 0;
1441
1442 copied = data_skb->len;
1443 if (len < copied) {
1444 msg->msg_flags |= MSG_TRUNC;
1445 copied = len;
1446 }
1447
1448 skb_reset_transport_header(data_skb);
1449 err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
1450
1451 if (msg->msg_name) {
1452 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1453 addr->nl_family = AF_NETLINK;
1454 addr->nl_pad = 0;
1455 addr->nl_pid = NETLINK_CB(skb).pid;
1456 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1457 msg->msg_namelen = sizeof(*addr);
1458 }
1459
1460 if (nlk->flags & NETLINK_RECV_PKTINFO)
1461 netlink_cmsg_recv_pktinfo(msg, skb);
1462
1463 if (NULL == siocb->scm) {
1464 memset(&scm, 0, sizeof(scm));
1465 siocb->scm = &scm;
1466 }
1467 siocb->scm->creds = *NETLINK_CREDS(skb);
1468 if (flags & MSG_TRUNC)
1469 copied = data_skb->len;
1470
1471 skb_free_datagram(sk, skb);
1472
1473 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1474 ret = netlink_dump(sk);
1475 if (ret) {
1476 sk->sk_err = ret;
1477 sk->sk_error_report(sk);
1478 }
1479 }
1480
1481 scm_recv(sock, msg, siocb->scm, flags);
1482 out:
1483 netlink_rcv_wake(sk);
1484 return err ? : copied;
1485 }
1486
1487 static void netlink_data_ready(struct sock *sk, int len)
1488 {
1489 BUG();
1490 }
1491
1492 /*
1493 * We export these functions to other modules. They provide a
1494 * complete set of kernel non-blocking support for message
1495 * queueing.
1496 */
1497
1498 struct sock *
1499 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1500 void (*input)(struct sk_buff *skb),
1501 struct mutex *cb_mutex, struct module *module)
1502 {
1503 struct socket *sock;
1504 struct sock *sk;
1505 struct netlink_sock *nlk;
1506 struct listeners *listeners = NULL;
1507
1508 BUG_ON(!nl_table);
1509
1510 if (unit < 0 || unit >= MAX_LINKS)
1511 return NULL;
1512
1513 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1514 return NULL;
1515
1516 /*
1517 * We have to just have a reference on the net from sk, but don't
1518 * get_net it. Besides, we cannot get and then put the net here.
1519 * So we create one inside init_net and the move it to net.
1520 */
1521
1522 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1523 goto out_sock_release_nosk;
1524
1525 sk = sock->sk;
1526 sk_change_net(sk, net);
1527
1528 if (groups < 32)
1529 groups = 32;
1530
1531 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
1532 if (!listeners)
1533 goto out_sock_release;
1534
1535 sk->sk_data_ready = netlink_data_ready;
1536 if (input)
1537 nlk_sk(sk)->netlink_rcv = input;
1538
1539 if (netlink_insert(sk, net, 0))
1540 goto out_sock_release;
1541
1542 nlk = nlk_sk(sk);
1543 nlk->flags |= NETLINK_KERNEL_SOCKET;
1544
1545 netlink_table_grab();
1546 if (!nl_table[unit].registered) {
1547 nl_table[unit].groups = groups;
1548 rcu_assign_pointer(nl_table[unit].listeners, listeners);
1549 nl_table[unit].cb_mutex = cb_mutex;
1550 nl_table[unit].module = module;
1551 nl_table[unit].registered = 1;
1552 } else {
1553 kfree(listeners);
1554 nl_table[unit].registered++;
1555 }
1556 netlink_table_ungrab();
1557 return sk;
1558
1559 out_sock_release:
1560 kfree(listeners);
1561 netlink_kernel_release(sk);
1562 return NULL;
1563
1564 out_sock_release_nosk:
1565 sock_release(sock);
1566 return NULL;
1567 }
1568 EXPORT_SYMBOL(netlink_kernel_create);
1569
1570
1571 void
1572 netlink_kernel_release(struct sock *sk)
1573 {
1574 sk_release_kernel(sk);
1575 }
1576 EXPORT_SYMBOL(netlink_kernel_release);
1577
1578
1579 static void listeners_free_rcu(struct rcu_head *head)
1580 {
1581 kfree(container_of(head, struct listeners, rcu));
1582 }
1583
1584 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1585 {
1586 struct listeners *new, *old;
1587 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1588
1589 if (groups < 32)
1590 groups = 32;
1591
1592 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1593 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
1594 if (!new)
1595 return -ENOMEM;
1596 old = rcu_dereference_raw(tbl->listeners);
1597 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
1598 rcu_assign_pointer(tbl->listeners, new);
1599
1600 call_rcu(&old->rcu, listeners_free_rcu);
1601 }
1602 tbl->groups = groups;
1603
1604 return 0;
1605 }
1606
1607 /**
1608 * netlink_change_ngroups - change number of multicast groups
1609 *
1610 * This changes the number of multicast groups that are available
1611 * on a certain netlink family. Note that it is not possible to
1612 * change the number of groups to below 32. Also note that it does
1613 * not implicitly call netlink_clear_multicast_users() when the
1614 * number of groups is reduced.
1615 *
1616 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1617 * @groups: The new number of groups.
1618 */
1619 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1620 {
1621 int err;
1622
1623 netlink_table_grab();
1624 err = __netlink_change_ngroups(sk, groups);
1625 netlink_table_ungrab();
1626
1627 return err;
1628 }
1629
1630 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1631 {
1632 struct sock *sk;
1633 struct hlist_node *node;
1634 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1635
1636 sk_for_each_bound(sk, node, &tbl->mc_list)
1637 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1638 }
1639
1640 /**
1641 * netlink_clear_multicast_users - kick off multicast listeners
1642 *
1643 * This function removes all listeners from the given group.
1644 * @ksk: The kernel netlink socket, as returned by
1645 * netlink_kernel_create().
1646 * @group: The multicast group to clear.
1647 */
1648 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1649 {
1650 netlink_table_grab();
1651 __netlink_clear_multicast_users(ksk, group);
1652 netlink_table_ungrab();
1653 }
1654
1655 void netlink_set_nonroot(int protocol, unsigned int flags)
1656 {
1657 if ((unsigned int)protocol < MAX_LINKS)
1658 nl_table[protocol].nl_nonroot = flags;
1659 }
1660 EXPORT_SYMBOL(netlink_set_nonroot);
1661
1662 static void netlink_destroy_callback(struct netlink_callback *cb)
1663 {
1664 kfree_skb(cb->skb);
1665 kfree(cb);
1666 }
1667
1668 /*
1669 * It looks a bit ugly.
1670 * It would be better to create kernel thread.
1671 */
1672
1673 static int netlink_dump(struct sock *sk)
1674 {
1675 struct netlink_sock *nlk = nlk_sk(sk);
1676 struct netlink_callback *cb;
1677 struct sk_buff *skb;
1678 struct nlmsghdr *nlh;
1679 int len, err = -ENOBUFS;
1680
1681 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1682 if (!skb)
1683 goto errout;
1684
1685 mutex_lock(nlk->cb_mutex);
1686
1687 cb = nlk->cb;
1688 if (cb == NULL) {
1689 err = -EINVAL;
1690 goto errout_skb;
1691 }
1692
1693 len = cb->dump(skb, cb);
1694
1695 if (len > 0) {
1696 mutex_unlock(nlk->cb_mutex);
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 return 0;
1705 }
1706
1707 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1708 if (!nlh)
1709 goto errout_skb;
1710
1711 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1712
1713 if (sk_filter(sk, skb))
1714 kfree_skb(skb);
1715 else {
1716 skb_queue_tail(&sk->sk_receive_queue, skb);
1717 sk->sk_data_ready(sk, skb->len);
1718 }
1719
1720 if (cb->done)
1721 cb->done(cb);
1722 nlk->cb = NULL;
1723 mutex_unlock(nlk->cb_mutex);
1724
1725 netlink_destroy_callback(cb);
1726 return 0;
1727
1728 errout_skb:
1729 mutex_unlock(nlk->cb_mutex);
1730 kfree_skb(skb);
1731 errout:
1732 return err;
1733 }
1734
1735 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1736 const struct nlmsghdr *nlh,
1737 int (*dump)(struct sk_buff *skb,
1738 struct netlink_callback *),
1739 int (*done)(struct netlink_callback *))
1740 {
1741 struct netlink_callback *cb;
1742 struct sock *sk;
1743 struct netlink_sock *nlk;
1744 int ret;
1745
1746 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1747 if (cb == NULL)
1748 return -ENOBUFS;
1749
1750 cb->dump = dump;
1751 cb->done = done;
1752 cb->nlh = nlh;
1753 atomic_inc(&skb->users);
1754 cb->skb = skb;
1755
1756 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1757 if (sk == NULL) {
1758 netlink_destroy_callback(cb);
1759 return -ECONNREFUSED;
1760 }
1761 nlk = nlk_sk(sk);
1762 /* A dump is in progress... */
1763 mutex_lock(nlk->cb_mutex);
1764 if (nlk->cb) {
1765 mutex_unlock(nlk->cb_mutex);
1766 netlink_destroy_callback(cb);
1767 sock_put(sk);
1768 return -EBUSY;
1769 }
1770 nlk->cb = cb;
1771 mutex_unlock(nlk->cb_mutex);
1772
1773 ret = netlink_dump(sk);
1774
1775 sock_put(sk);
1776
1777 if (ret)
1778 return ret;
1779
1780 /* We successfully started a dump, by returning -EINTR we
1781 * signal not to send ACK even if it was requested.
1782 */
1783 return -EINTR;
1784 }
1785 EXPORT_SYMBOL(netlink_dump_start);
1786
1787 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1788 {
1789 struct sk_buff *skb;
1790 struct nlmsghdr *rep;
1791 struct nlmsgerr *errmsg;
1792 size_t payload = sizeof(*errmsg);
1793
1794 /* error messages get the original request appened */
1795 if (err)
1796 payload += nlmsg_len(nlh);
1797
1798 skb = nlmsg_new(payload, GFP_KERNEL);
1799 if (!skb) {
1800 struct sock *sk;
1801
1802 sk = netlink_lookup(sock_net(in_skb->sk),
1803 in_skb->sk->sk_protocol,
1804 NETLINK_CB(in_skb).pid);
1805 if (sk) {
1806 sk->sk_err = ENOBUFS;
1807 sk->sk_error_report(sk);
1808 sock_put(sk);
1809 }
1810 return;
1811 }
1812
1813 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1814 NLMSG_ERROR, payload, 0);
1815 errmsg = nlmsg_data(rep);
1816 errmsg->error = err;
1817 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1818 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1819 }
1820 EXPORT_SYMBOL(netlink_ack);
1821
1822 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1823 struct nlmsghdr *))
1824 {
1825 struct nlmsghdr *nlh;
1826 int err;
1827
1828 while (skb->len >= nlmsg_total_size(0)) {
1829 int msglen;
1830
1831 nlh = nlmsg_hdr(skb);
1832 err = 0;
1833
1834 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1835 return 0;
1836
1837 /* Only requests are handled by the kernel */
1838 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1839 goto ack;
1840
1841 /* Skip control messages */
1842 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1843 goto ack;
1844
1845 err = cb(skb, nlh);
1846 if (err == -EINTR)
1847 goto skip;
1848
1849 ack:
1850 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1851 netlink_ack(skb, nlh, err);
1852
1853 skip:
1854 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1855 if (msglen > skb->len)
1856 msglen = skb->len;
1857 skb_pull(skb, msglen);
1858 }
1859
1860 return 0;
1861 }
1862 EXPORT_SYMBOL(netlink_rcv_skb);
1863
1864 /**
1865 * nlmsg_notify - send a notification netlink message
1866 * @sk: netlink socket to use
1867 * @skb: notification message
1868 * @pid: destination netlink pid for reports or 0
1869 * @group: destination multicast group or 0
1870 * @report: 1 to report back, 0 to disable
1871 * @flags: allocation flags
1872 */
1873 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1874 unsigned int group, int report, gfp_t flags)
1875 {
1876 int err = 0;
1877
1878 if (group) {
1879 int exclude_pid = 0;
1880
1881 if (report) {
1882 atomic_inc(&skb->users);
1883 exclude_pid = pid;
1884 }
1885
1886 /* errors reported via destination sk->sk_err, but propagate
1887 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1888 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1889 }
1890
1891 if (report) {
1892 int err2;
1893
1894 err2 = nlmsg_unicast(sk, skb, pid);
1895 if (!err || err == -ESRCH)
1896 err = err2;
1897 }
1898
1899 return err;
1900 }
1901 EXPORT_SYMBOL(nlmsg_notify);
1902
1903 #ifdef CONFIG_PROC_FS
1904 struct nl_seq_iter {
1905 struct seq_net_private p;
1906 int link;
1907 int hash_idx;
1908 };
1909
1910 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1911 {
1912 struct nl_seq_iter *iter = seq->private;
1913 int i, j;
1914 struct sock *s;
1915 struct hlist_node *node;
1916 loff_t off = 0;
1917
1918 for (i = 0; i < MAX_LINKS; i++) {
1919 struct nl_pid_hash *hash = &nl_table[i].hash;
1920
1921 for (j = 0; j <= hash->mask; j++) {
1922 sk_for_each(s, node, &hash->table[j]) {
1923 if (sock_net(s) != seq_file_net(seq))
1924 continue;
1925 if (off == pos) {
1926 iter->link = i;
1927 iter->hash_idx = j;
1928 return s;
1929 }
1930 ++off;
1931 }
1932 }
1933 }
1934 return NULL;
1935 }
1936
1937 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1938 __acquires(nl_table_lock)
1939 {
1940 read_lock(&nl_table_lock);
1941 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1942 }
1943
1944 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1945 {
1946 struct sock *s;
1947 struct nl_seq_iter *iter;
1948 int i, j;
1949
1950 ++*pos;
1951
1952 if (v == SEQ_START_TOKEN)
1953 return netlink_seq_socket_idx(seq, 0);
1954
1955 iter = seq->private;
1956 s = v;
1957 do {
1958 s = sk_next(s);
1959 } while (s && sock_net(s) != seq_file_net(seq));
1960 if (s)
1961 return s;
1962
1963 i = iter->link;
1964 j = iter->hash_idx + 1;
1965
1966 do {
1967 struct nl_pid_hash *hash = &nl_table[i].hash;
1968
1969 for (; j <= hash->mask; j++) {
1970 s = sk_head(&hash->table[j]);
1971 while (s && sock_net(s) != seq_file_net(seq))
1972 s = sk_next(s);
1973 if (s) {
1974 iter->link = i;
1975 iter->hash_idx = j;
1976 return s;
1977 }
1978 }
1979
1980 j = 0;
1981 } while (++i < MAX_LINKS);
1982
1983 return NULL;
1984 }
1985
1986 static void netlink_seq_stop(struct seq_file *seq, void *v)
1987 __releases(nl_table_lock)
1988 {
1989 read_unlock(&nl_table_lock);
1990 }
1991
1992
1993 static int netlink_seq_show(struct seq_file *seq, void *v)
1994 {
1995 if (v == SEQ_START_TOKEN)
1996 seq_puts(seq,
1997 "sk Eth Pid Groups "
1998 "Rmem Wmem Dump Locks Drops Inode\n");
1999 else {
2000 struct sock *s = v;
2001 struct netlink_sock *nlk = nlk_sk(s);
2002
2003 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %-8d %-8d %-8lu\n",
2004 s,
2005 s->sk_protocol,
2006 nlk->pid,
2007 nlk->groups ? (u32)nlk->groups[0] : 0,
2008 sk_rmem_alloc_get(s),
2009 sk_wmem_alloc_get(s),
2010 nlk->cb,
2011 atomic_read(&s->sk_refcnt),
2012 atomic_read(&s->sk_drops),
2013 sock_i_ino(s)
2014 );
2015
2016 }
2017 return 0;
2018 }
2019
2020 static const struct seq_operations netlink_seq_ops = {
2021 .start = netlink_seq_start,
2022 .next = netlink_seq_next,
2023 .stop = netlink_seq_stop,
2024 .show = netlink_seq_show,
2025 };
2026
2027
2028 static int netlink_seq_open(struct inode *inode, struct file *file)
2029 {
2030 return seq_open_net(inode, file, &netlink_seq_ops,
2031 sizeof(struct nl_seq_iter));
2032 }
2033
2034 static const struct file_operations netlink_seq_fops = {
2035 .owner = THIS_MODULE,
2036 .open = netlink_seq_open,
2037 .read = seq_read,
2038 .llseek = seq_lseek,
2039 .release = seq_release_net,
2040 };
2041
2042 #endif
2043
2044 int netlink_register_notifier(struct notifier_block *nb)
2045 {
2046 return atomic_notifier_chain_register(&netlink_chain, nb);
2047 }
2048 EXPORT_SYMBOL(netlink_register_notifier);
2049
2050 int netlink_unregister_notifier(struct notifier_block *nb)
2051 {
2052 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2053 }
2054 EXPORT_SYMBOL(netlink_unregister_notifier);
2055
2056 static const struct proto_ops netlink_ops = {
2057 .family = PF_NETLINK,
2058 .owner = THIS_MODULE,
2059 .release = netlink_release,
2060 .bind = netlink_bind,
2061 .connect = netlink_connect,
2062 .socketpair = sock_no_socketpair,
2063 .accept = sock_no_accept,
2064 .getname = netlink_getname,
2065 .poll = datagram_poll,
2066 .ioctl = sock_no_ioctl,
2067 .listen = sock_no_listen,
2068 .shutdown = sock_no_shutdown,
2069 .setsockopt = netlink_setsockopt,
2070 .getsockopt = netlink_getsockopt,
2071 .sendmsg = netlink_sendmsg,
2072 .recvmsg = netlink_recvmsg,
2073 .mmap = sock_no_mmap,
2074 .sendpage = sock_no_sendpage,
2075 };
2076
2077 static const struct net_proto_family netlink_family_ops = {
2078 .family = PF_NETLINK,
2079 .create = netlink_create,
2080 .owner = THIS_MODULE, /* for consistency 8) */
2081 };
2082
2083 static int __net_init netlink_net_init(struct net *net)
2084 {
2085 #ifdef CONFIG_PROC_FS
2086 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2087 return -ENOMEM;
2088 #endif
2089 return 0;
2090 }
2091
2092 static void __net_exit netlink_net_exit(struct net *net)
2093 {
2094 #ifdef CONFIG_PROC_FS
2095 proc_net_remove(net, "netlink");
2096 #endif
2097 }
2098
2099 static void __init netlink_add_usersock_entry(void)
2100 {
2101 struct listeners *listeners;
2102 int groups = 32;
2103
2104 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2105 if (!listeners)
2106 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2107
2108 netlink_table_grab();
2109
2110 nl_table[NETLINK_USERSOCK].groups = groups;
2111 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2112 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2113 nl_table[NETLINK_USERSOCK].registered = 1;
2114
2115 netlink_table_ungrab();
2116 }
2117
2118 static struct pernet_operations __net_initdata netlink_net_ops = {
2119 .init = netlink_net_init,
2120 .exit = netlink_net_exit,
2121 };
2122
2123 static int __init netlink_proto_init(void)
2124 {
2125 struct sk_buff *dummy_skb;
2126 int i;
2127 unsigned long limit;
2128 unsigned int order;
2129 int err = proto_register(&netlink_proto, 0);
2130
2131 if (err != 0)
2132 goto out;
2133
2134 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2135
2136 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2137 if (!nl_table)
2138 goto panic;
2139
2140 if (totalram_pages >= (128 * 1024))
2141 limit = totalram_pages >> (21 - PAGE_SHIFT);
2142 else
2143 limit = totalram_pages >> (23 - PAGE_SHIFT);
2144
2145 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2146 limit = (1UL << order) / sizeof(struct hlist_head);
2147 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2148
2149 for (i = 0; i < MAX_LINKS; i++) {
2150 struct nl_pid_hash *hash = &nl_table[i].hash;
2151
2152 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
2153 if (!hash->table) {
2154 while (i-- > 0)
2155 nl_pid_hash_free(nl_table[i].hash.table,
2156 1 * sizeof(*hash->table));
2157 kfree(nl_table);
2158 goto panic;
2159 }
2160 hash->max_shift = order;
2161 hash->shift = 0;
2162 hash->mask = 0;
2163 hash->rehash_time = jiffies;
2164 }
2165
2166 netlink_add_usersock_entry();
2167
2168 sock_register(&netlink_family_ops);
2169 register_pernet_subsys(&netlink_net_ops);
2170 /* The netlink device handler may be needed early. */
2171 rtnetlink_init();
2172 out:
2173 return err;
2174 panic:
2175 panic("netlink_init: Cannot allocate nl_table\n");
2176 }
2177
2178 core_initcall(netlink_proto_init);
Linux with added FPC-III support