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debugfs: Modified default dir of debugfs for debugging UHCI.
[linux/fpc-iii.git] / net / netlink / af_netlink.c
blobd0ff382c40ca96cfe66752379039218714c966a1
1 /*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
13 * added netlink_proto_exit
14 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
15 * use nlk_sk, as sk->protinfo is on a diet 8)
16 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
17 * - inc module use count of module that owns
18 * the kernel socket in case userspace opens
19 * socket of same protocol
20 * - remove all module support, since netlink is
21 * mandatory if CONFIG_NET=y these days
22 */
23
24 #include <linux/module.h>
25
26 #include <linux/capability.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/signal.h>
30 #include <linux/sched.h>
31 #include <linux/errno.h>
32 #include <linux/string.h>
33 #include <linux/stat.h>
34 #include <linux/socket.h>
35 #include <linux/un.h>
36 #include <linux/fcntl.h>
37 #include <linux/termios.h>
38 #include <linux/sockios.h>
39 #include <linux/net.h>
40 #include <linux/fs.h>
41 #include <linux/slab.h>
42 #include <asm/uaccess.h>
43 #include <linux/skbuff.h>
44 #include <linux/netdevice.h>
45 #include <linux/rtnetlink.h>
46 #include <linux/proc_fs.h>
47 #include <linux/seq_file.h>
48 #include <linux/notifier.h>
49 #include <linux/security.h>
50 #include <linux/jhash.h>
51 #include <linux/jiffies.h>
52 #include <linux/random.h>
53 #include <linux/bitops.h>
54 #include <linux/mm.h>
55 #include <linux/types.h>
56 #include <linux/audit.h>
57 #include <linux/mutex.h>
58
59 #include <net/net_namespace.h>
60 #include <net/sock.h>
61 #include <net/scm.h>
62 #include <net/netlink.h>
63
64 #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
65 #define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long))
66
67 struct netlink_sock {
68 /* struct sock has to be the first member of netlink_sock */
69 struct sock sk;
70 u32 pid;
71 u32 dst_pid;
72 u32 dst_group;
73 u32 flags;
74 u32 subscriptions;
75 u32 ngroups;
76 unsigned long *groups;
77 unsigned long state;
78 wait_queue_head_t wait;
79 struct netlink_callback *cb;
80 struct mutex *cb_mutex;
81 struct mutex cb_def_mutex;
82 void (*netlink_rcv)(struct sk_buff *skb);
83 struct module *module;
84 };
85
86 struct listeners_rcu_head {
87 struct rcu_head rcu_head;
88 void *ptr;
89 };
90
91 #define NETLINK_KERNEL_SOCKET 0x1
92 #define NETLINK_RECV_PKTINFO 0x2
93 #define NETLINK_BROADCAST_SEND_ERROR 0x4
94 #define NETLINK_RECV_NO_ENOBUFS 0x8
95
96 static inline struct netlink_sock *nlk_sk(struct sock *sk)
97 {
98 return container_of(sk, struct netlink_sock, sk);
99 }
100
101 static inline int netlink_is_kernel(struct sock *sk)
102 {
103 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
104 }
105
106 struct nl_pid_hash {
107 struct hlist_head *table;
108 unsigned long rehash_time;
109
110 unsigned int mask;
111 unsigned int shift;
112
113 unsigned int entries;
114 unsigned int max_shift;
115
116 u32 rnd;
117 };
118
119 struct netlink_table {
120 struct nl_pid_hash hash;
121 struct hlist_head mc_list;
122 unsigned long *listeners;
123 unsigned int nl_nonroot;
124 unsigned int groups;
125 struct mutex *cb_mutex;
126 struct module *module;
127 int registered;
128 };
129
130 static struct netlink_table *nl_table;
131
132 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
133
134 static int netlink_dump(struct sock *sk);
135 static void netlink_destroy_callback(struct netlink_callback *cb);
136
137 static DEFINE_RWLOCK(nl_table_lock);
138 static atomic_t nl_table_users = ATOMIC_INIT(0);
139
140 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
141
142 static u32 netlink_group_mask(u32 group)
143 {
144 return group ? 1 << (group - 1) : 0;
145 }
146
147 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
148 {
149 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
150 }
151
152 static void netlink_sock_destruct(struct sock *sk)
153 {
154 struct netlink_sock *nlk = nlk_sk(sk);
155
156 if (nlk->cb) {
157 if (nlk->cb->done)
158 nlk->cb->done(nlk->cb);
159 netlink_destroy_callback(nlk->cb);
160 }
161
162 skb_queue_purge(&sk->sk_receive_queue);
163
164 if (!sock_flag(sk, SOCK_DEAD)) {
165 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
166 return;
167 }
168
169 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
170 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
171 WARN_ON(nlk_sk(sk)->groups);
172 }
173
174 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
175 * SMP. Look, when several writers sleep and reader wakes them up, all but one
176 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
177 * this, _but_ remember, it adds useless work on UP machines.
178 */
179
180 static void netlink_table_grab(void)
181 __acquires(nl_table_lock)
182 {
183 write_lock_irq(&nl_table_lock);
184
185 if (atomic_read(&nl_table_users)) {
186 DECLARE_WAITQUEUE(wait, current);
187
188 add_wait_queue_exclusive(&nl_table_wait, &wait);
189 for (;;) {
190 set_current_state(TASK_UNINTERRUPTIBLE);
191 if (atomic_read(&nl_table_users) == 0)
192 break;
193 write_unlock_irq(&nl_table_lock);
194 schedule();
195 write_lock_irq(&nl_table_lock);
196 }
197
198 __set_current_state(TASK_RUNNING);
199 remove_wait_queue(&nl_table_wait, &wait);
200 }
201 }
202
203 static void netlink_table_ungrab(void)
204 __releases(nl_table_lock)
205 {
206 write_unlock_irq(&nl_table_lock);
207 wake_up(&nl_table_wait);
208 }
209
210 static inline void
211 netlink_lock_table(void)
212 {
213 /* read_lock() synchronizes us to netlink_table_grab */
214
215 read_lock(&nl_table_lock);
216 atomic_inc(&nl_table_users);
217 read_unlock(&nl_table_lock);
218 }
219
220 static inline void
221 netlink_unlock_table(void)
222 {
223 if (atomic_dec_and_test(&nl_table_users))
224 wake_up(&nl_table_wait);
225 }
226
227 static inline struct sock *netlink_lookup(struct net *net, int protocol,
228 u32 pid)
229 {
230 struct nl_pid_hash *hash = &nl_table[protocol].hash;
231 struct hlist_head *head;
232 struct sock *sk;
233 struct hlist_node *node;
234
235 read_lock(&nl_table_lock);
236 head = nl_pid_hashfn(hash, pid);
237 sk_for_each(sk, node, head) {
238 if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) {
239 sock_hold(sk);
240 goto found;
241 }
242 }
243 sk = NULL;
244 found:
245 read_unlock(&nl_table_lock);
246 return sk;
247 }
248
249 static inline struct hlist_head *nl_pid_hash_zalloc(size_t size)
250 {
251 if (size <= PAGE_SIZE)
252 return kzalloc(size, GFP_ATOMIC);
253 else
254 return (struct hlist_head *)
255 __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
256 get_order(size));
257 }
258
259 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
260 {
261 if (size <= PAGE_SIZE)
262 kfree(table);
263 else
264 free_pages((unsigned long)table, get_order(size));
265 }
266
267 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
268 {
269 unsigned int omask, mask, shift;
270 size_t osize, size;
271 struct hlist_head *otable, *table;
272 int i;
273
274 omask = mask = hash->mask;
275 osize = size = (mask + 1) * sizeof(*table);
276 shift = hash->shift;
277
278 if (grow) {
279 if (++shift > hash->max_shift)
280 return 0;
281 mask = mask * 2 + 1;
282 size *= 2;
283 }
284
285 table = nl_pid_hash_zalloc(size);
286 if (!table)
287 return 0;
288
289 otable = hash->table;
290 hash->table = table;
291 hash->mask = mask;
292 hash->shift = shift;
293 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
294
295 for (i = 0; i <= omask; i++) {
296 struct sock *sk;
297 struct hlist_node *node, *tmp;
298
299 sk_for_each_safe(sk, node, tmp, &otable[i])
300 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
301 }
302
303 nl_pid_hash_free(otable, osize);
304 hash->rehash_time = jiffies + 10 * 60 * HZ;
305 return 1;
306 }
307
308 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
309 {
310 int avg = hash->entries >> hash->shift;
311
312 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
313 return 1;
314
315 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
316 nl_pid_hash_rehash(hash, 0);
317 return 1;
318 }
319
320 return 0;
321 }
322
323 static const struct proto_ops netlink_ops;
324
325 static void
326 netlink_update_listeners(struct sock *sk)
327 {
328 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
329 struct hlist_node *node;
330 unsigned long mask;
331 unsigned int i;
332
333 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
334 mask = 0;
335 sk_for_each_bound(sk, node, &tbl->mc_list) {
336 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
337 mask |= nlk_sk(sk)->groups[i];
338 }
339 tbl->listeners[i] = mask;
340 }
341 /* this function is only called with the netlink table "grabbed", which
342 * makes sure updates are visible before bind or setsockopt return. */
343 }
344
345 static int netlink_insert(struct sock *sk, struct net *net, u32 pid)
346 {
347 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
348 struct hlist_head *head;
349 int err = -EADDRINUSE;
350 struct sock *osk;
351 struct hlist_node *node;
352 int len;
353
354 netlink_table_grab();
355 head = nl_pid_hashfn(hash, pid);
356 len = 0;
357 sk_for_each(osk, node, head) {
358 if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->pid == pid))
359 break;
360 len++;
361 }
362 if (node)
363 goto err;
364
365 err = -EBUSY;
366 if (nlk_sk(sk)->pid)
367 goto err;
368
369 err = -ENOMEM;
370 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
371 goto err;
372
373 if (len && nl_pid_hash_dilute(hash, len))
374 head = nl_pid_hashfn(hash, pid);
375 hash->entries++;
376 nlk_sk(sk)->pid = pid;
377 sk_add_node(sk, head);
378 err = 0;
379
380 err:
381 netlink_table_ungrab();
382 return err;
383 }
384
385 static void netlink_remove(struct sock *sk)
386 {
387 netlink_table_grab();
388 if (sk_del_node_init(sk))
389 nl_table[sk->sk_protocol].hash.entries--;
390 if (nlk_sk(sk)->subscriptions)
391 __sk_del_bind_node(sk);
392 netlink_table_ungrab();
393 }
394
395 static struct proto netlink_proto = {
396 .name = "NETLINK",
397 .owner = THIS_MODULE,
398 .obj_size = sizeof(struct netlink_sock),
399 };
400
401 static int __netlink_create(struct net *net, struct socket *sock,
402 struct mutex *cb_mutex, int protocol)
403 {
404 struct sock *sk;
405 struct netlink_sock *nlk;
406
407 sock->ops = &netlink_ops;
408
409 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
410 if (!sk)
411 return -ENOMEM;
412
413 sock_init_data(sock, sk);
414
415 nlk = nlk_sk(sk);
416 if (cb_mutex)
417 nlk->cb_mutex = cb_mutex;
418 else {
419 nlk->cb_mutex = &nlk->cb_def_mutex;
420 mutex_init(nlk->cb_mutex);
421 }
422 init_waitqueue_head(&nlk->wait);
423
424 sk->sk_destruct = netlink_sock_destruct;
425 sk->sk_protocol = protocol;
426 return 0;
427 }
428
429 static int netlink_create(struct net *net, struct socket *sock, int protocol)
430 {
431 struct module *module = NULL;
432 struct mutex *cb_mutex;
433 struct netlink_sock *nlk;
434 int err = 0;
435
436 sock->state = SS_UNCONNECTED;
437
438 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
439 return -ESOCKTNOSUPPORT;
440
441 if (protocol < 0 || protocol >= MAX_LINKS)
442 return -EPROTONOSUPPORT;
443
444 netlink_lock_table();
445 #ifdef CONFIG_MODULES
446 if (!nl_table[protocol].registered) {
447 netlink_unlock_table();
448 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
449 netlink_lock_table();
450 }
451 #endif
452 if (nl_table[protocol].registered &&
453 try_module_get(nl_table[protocol].module))
454 module = nl_table[protocol].module;
455 cb_mutex = nl_table[protocol].cb_mutex;
456 netlink_unlock_table();
457
458 err = __netlink_create(net, sock, cb_mutex, protocol);
459 if (err < 0)
460 goto out_module;
461
462 local_bh_disable();
463 sock_prot_inuse_add(net, &netlink_proto, 1);
464 local_bh_enable();
465
466 nlk = nlk_sk(sock->sk);
467 nlk->module = module;
468 out:
469 return err;
470
471 out_module:
472 module_put(module);
473 goto out;
474 }
475
476 static int netlink_release(struct socket *sock)
477 {
478 struct sock *sk = sock->sk;
479 struct netlink_sock *nlk;
480
481 if (!sk)
482 return 0;
483
484 netlink_remove(sk);
485 sock_orphan(sk);
486 nlk = nlk_sk(sk);
487
488 /*
489 * OK. Socket is unlinked, any packets that arrive now
490 * will be purged.
491 */
492
493 sock->sk = NULL;
494 wake_up_interruptible_all(&nlk->wait);
495
496 skb_queue_purge(&sk->sk_write_queue);
497
498 if (nlk->pid && !nlk->subscriptions) {
499 struct netlink_notify n = {
500 .net = sock_net(sk),
501 .protocol = sk->sk_protocol,
502 .pid = nlk->pid,
503 };
504 atomic_notifier_call_chain(&netlink_chain,
505 NETLINK_URELEASE, &n);
506 }
507
508 module_put(nlk->module);
509
510 netlink_table_grab();
511 if (netlink_is_kernel(sk)) {
512 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
513 if (--nl_table[sk->sk_protocol].registered == 0) {
514 kfree(nl_table[sk->sk_protocol].listeners);
515 nl_table[sk->sk_protocol].module = NULL;
516 nl_table[sk->sk_protocol].registered = 0;
517 }
518 } else if (nlk->subscriptions)
519 netlink_update_listeners(sk);
520 netlink_table_ungrab();
521
522 kfree(nlk->groups);
523 nlk->groups = NULL;
524
525 local_bh_disable();
526 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
527 local_bh_enable();
528 sock_put(sk);
529 return 0;
530 }
531
532 static int netlink_autobind(struct socket *sock)
533 {
534 struct sock *sk = sock->sk;
535 struct net *net = sock_net(sk);
536 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
537 struct hlist_head *head;
538 struct sock *osk;
539 struct hlist_node *node;
540 s32 pid = current->tgid;
541 int err;
542 static s32 rover = -4097;
543
544 retry:
545 cond_resched();
546 netlink_table_grab();
547 head = nl_pid_hashfn(hash, pid);
548 sk_for_each(osk, node, head) {
549 if (!net_eq(sock_net(osk), net))
550 continue;
551 if (nlk_sk(osk)->pid == pid) {
552 /* Bind collision, search negative pid values. */
553 pid = rover--;
554 if (rover > -4097)
555 rover = -4097;
556 netlink_table_ungrab();
557 goto retry;
558 }
559 }
560 netlink_table_ungrab();
561
562 err = netlink_insert(sk, net, pid);
563 if (err == -EADDRINUSE)
564 goto retry;
565
566 /* If 2 threads race to autobind, that is fine. */
567 if (err == -EBUSY)
568 err = 0;
569
570 return err;
571 }
572
573 static inline int netlink_capable(struct socket *sock, unsigned int flag)
574 {
575 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
576 capable(CAP_NET_ADMIN);
577 }
578
579 static void
580 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
581 {
582 struct netlink_sock *nlk = nlk_sk(sk);
583
584 if (nlk->subscriptions && !subscriptions)
585 __sk_del_bind_node(sk);
586 else if (!nlk->subscriptions && subscriptions)
587 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
588 nlk->subscriptions = subscriptions;
589 }
590
591 static int netlink_realloc_groups(struct sock *sk)
592 {
593 struct netlink_sock *nlk = nlk_sk(sk);
594 unsigned int groups;
595 unsigned long *new_groups;
596 int err = 0;
597
598 netlink_table_grab();
599
600 groups = nl_table[sk->sk_protocol].groups;
601 if (!nl_table[sk->sk_protocol].registered) {
602 err = -ENOENT;
603 goto out_unlock;
604 }
605
606 if (nlk->ngroups >= groups)
607 goto out_unlock;
608
609 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
610 if (new_groups == NULL) {
611 err = -ENOMEM;
612 goto out_unlock;
613 }
614 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
615 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
616
617 nlk->groups = new_groups;
618 nlk->ngroups = groups;
619 out_unlock:
620 netlink_table_ungrab();
621 return err;
622 }
623
624 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
625 int addr_len)
626 {
627 struct sock *sk = sock->sk;
628 struct net *net = sock_net(sk);
629 struct netlink_sock *nlk = nlk_sk(sk);
630 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
631 int err;
632
633 if (nladdr->nl_family != AF_NETLINK)
634 return -EINVAL;
635
636 /* Only superuser is allowed to listen multicasts */
637 if (nladdr->nl_groups) {
638 if (!netlink_capable(sock, NL_NONROOT_RECV))
639 return -EPERM;
640 err = netlink_realloc_groups(sk);
641 if (err)
642 return err;
643 }
644
645 if (nlk->pid) {
646 if (nladdr->nl_pid != nlk->pid)
647 return -EINVAL;
648 } else {
649 err = nladdr->nl_pid ?
650 netlink_insert(sk, net, nladdr->nl_pid) :
651 netlink_autobind(sock);
652 if (err)
653 return err;
654 }
655
656 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
657 return 0;
658
659 netlink_table_grab();
660 netlink_update_subscriptions(sk, nlk->subscriptions +
661 hweight32(nladdr->nl_groups) -
662 hweight32(nlk->groups[0]));
663 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
664 netlink_update_listeners(sk);
665 netlink_table_ungrab();
666
667 return 0;
668 }
669
670 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
671 int alen, int flags)
672 {
673 int err = 0;
674 struct sock *sk = sock->sk;
675 struct netlink_sock *nlk = nlk_sk(sk);
676 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
677
678 if (addr->sa_family == AF_UNSPEC) {
679 sk->sk_state = NETLINK_UNCONNECTED;
680 nlk->dst_pid = 0;
681 nlk->dst_group = 0;
682 return 0;
683 }
684 if (addr->sa_family != AF_NETLINK)
685 return -EINVAL;
686
687 /* Only superuser is allowed to send multicasts */
688 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
689 return -EPERM;
690
691 if (!nlk->pid)
692 err = netlink_autobind(sock);
693
694 if (err == 0) {
695 sk->sk_state = NETLINK_CONNECTED;
696 nlk->dst_pid = nladdr->nl_pid;
697 nlk->dst_group = ffs(nladdr->nl_groups);
698 }
699
700 return err;
701 }
702
703 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
704 int *addr_len, int peer)
705 {
706 struct sock *sk = sock->sk;
707 struct netlink_sock *nlk = nlk_sk(sk);
708 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
709
710 nladdr->nl_family = AF_NETLINK;
711 nladdr->nl_pad = 0;
712 *addr_len = sizeof(*nladdr);
713
714 if (peer) {
715 nladdr->nl_pid = nlk->dst_pid;
716 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
717 } else {
718 nladdr->nl_pid = nlk->pid;
719 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
720 }
721 return 0;
722 }
723
724 static void netlink_overrun(struct sock *sk)
725 {
726 struct netlink_sock *nlk = nlk_sk(sk);
727
728 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
729 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
730 sk->sk_err = ENOBUFS;
731 sk->sk_error_report(sk);
732 }
733 }
734 atomic_inc(&sk->sk_drops);
735 }
736
737 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
738 {
739 struct sock *sock;
740 struct netlink_sock *nlk;
741
742 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid);
743 if (!sock)
744 return ERR_PTR(-ECONNREFUSED);
745
746 /* Don't bother queuing skb if kernel socket has no input function */
747 nlk = nlk_sk(sock);
748 if (sock->sk_state == NETLINK_CONNECTED &&
749 nlk->dst_pid != nlk_sk(ssk)->pid) {
750 sock_put(sock);
751 return ERR_PTR(-ECONNREFUSED);
752 }
753 return sock;
754 }
755
756 struct sock *netlink_getsockbyfilp(struct file *filp)
757 {
758 struct inode *inode = filp->f_path.dentry->d_inode;
759 struct sock *sock;
760
761 if (!S_ISSOCK(inode->i_mode))
762 return ERR_PTR(-ENOTSOCK);
763
764 sock = SOCKET_I(inode)->sk;
765 if (sock->sk_family != AF_NETLINK)
766 return ERR_PTR(-EINVAL);
767
768 sock_hold(sock);
769 return sock;
770 }
771
772 /*
773 * Attach a skb to a netlink socket.
774 * The caller must hold a reference to the destination socket. On error, the
775 * reference is dropped. The skb is not send to the destination, just all
776 * all error checks are performed and memory in the queue is reserved.
777 * Return values:
778 * < 0: error. skb freed, reference to sock dropped.
779 * 0: continue
780 * 1: repeat lookup - reference dropped while waiting for socket memory.
781 */
782 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
783 long *timeo, struct sock *ssk)
784 {
785 struct netlink_sock *nlk;
786
787 nlk = nlk_sk(sk);
788
789 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
790 test_bit(0, &nlk->state)) {
791 DECLARE_WAITQUEUE(wait, current);
792 if (!*timeo) {
793 if (!ssk || netlink_is_kernel(ssk))
794 netlink_overrun(sk);
795 sock_put(sk);
796 kfree_skb(skb);
797 return -EAGAIN;
798 }
799
800 __set_current_state(TASK_INTERRUPTIBLE);
801 add_wait_queue(&nlk->wait, &wait);
802
803 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
804 test_bit(0, &nlk->state)) &&
805 !sock_flag(sk, SOCK_DEAD))
806 *timeo = schedule_timeout(*timeo);
807
808 __set_current_state(TASK_RUNNING);
809 remove_wait_queue(&nlk->wait, &wait);
810 sock_put(sk);
811
812 if (signal_pending(current)) {
813 kfree_skb(skb);
814 return sock_intr_errno(*timeo);
815 }
816 return 1;
817 }
818 skb_set_owner_r(skb, sk);
819 return 0;
820 }
821
822 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
823 {
824 int len = skb->len;
825
826 skb_queue_tail(&sk->sk_receive_queue, skb);
827 sk->sk_data_ready(sk, len);
828 sock_put(sk);
829 return len;
830 }
831
832 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
833 {
834 kfree_skb(skb);
835 sock_put(sk);
836 }
837
838 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
839 gfp_t allocation)
840 {
841 int delta;
842
843 skb_orphan(skb);
844
845 delta = skb->end - skb->tail;
846 if (delta * 2 < skb->truesize)
847 return skb;
848
849 if (skb_shared(skb)) {
850 struct sk_buff *nskb = skb_clone(skb, allocation);
851 if (!nskb)
852 return skb;
853 kfree_skb(skb);
854 skb = nskb;
855 }
856
857 if (!pskb_expand_head(skb, 0, -delta, allocation))
858 skb->truesize -= delta;
859
860 return skb;
861 }
862
863 static inline void netlink_rcv_wake(struct sock *sk)
864 {
865 struct netlink_sock *nlk = nlk_sk(sk);
866
867 if (skb_queue_empty(&sk->sk_receive_queue))
868 clear_bit(0, &nlk->state);
869 if (!test_bit(0, &nlk->state))
870 wake_up_interruptible(&nlk->wait);
871 }
872
873 static inline int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb)
874 {
875 int ret;
876 struct netlink_sock *nlk = nlk_sk(sk);
877
878 ret = -ECONNREFUSED;
879 if (nlk->netlink_rcv != NULL) {
880 ret = skb->len;
881 skb_set_owner_r(skb, sk);
882 nlk->netlink_rcv(skb);
883 }
884 kfree_skb(skb);
885 sock_put(sk);
886 return ret;
887 }
888
889 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
890 u32 pid, int nonblock)
891 {
892 struct sock *sk;
893 int err;
894 long timeo;
895
896 skb = netlink_trim(skb, gfp_any());
897
898 timeo = sock_sndtimeo(ssk, nonblock);
899 retry:
900 sk = netlink_getsockbypid(ssk, pid);
901 if (IS_ERR(sk)) {
902 kfree_skb(skb);
903 return PTR_ERR(sk);
904 }
905 if (netlink_is_kernel(sk))
906 return netlink_unicast_kernel(sk, skb);
907
908 if (sk_filter(sk, skb)) {
909 err = skb->len;
910 kfree_skb(skb);
911 sock_put(sk);
912 return err;
913 }
914
915 err = netlink_attachskb(sk, skb, &timeo, ssk);
916 if (err == 1)
917 goto retry;
918 if (err)
919 return err;
920
921 return netlink_sendskb(sk, skb);
922 }
923 EXPORT_SYMBOL(netlink_unicast);
924
925 int netlink_has_listeners(struct sock *sk, unsigned int group)
926 {
927 int res = 0;
928 unsigned long *listeners;
929
930 BUG_ON(!netlink_is_kernel(sk));
931
932 rcu_read_lock();
933 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
934
935 if (group - 1 < nl_table[sk->sk_protocol].groups)
936 res = test_bit(group - 1, listeners);
937
938 rcu_read_unlock();
939
940 return res;
941 }
942 EXPORT_SYMBOL_GPL(netlink_has_listeners);
943
944 static inline int netlink_broadcast_deliver(struct sock *sk,
945 struct sk_buff *skb)
946 {
947 struct netlink_sock *nlk = nlk_sk(sk);
948
949 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
950 !test_bit(0, &nlk->state)) {
951 skb_set_owner_r(skb, sk);
952 skb_queue_tail(&sk->sk_receive_queue, skb);
953 sk->sk_data_ready(sk, skb->len);
954 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
955 }
956 return -1;
957 }
958
959 struct netlink_broadcast_data {
960 struct sock *exclude_sk;
961 struct net *net;
962 u32 pid;
963 u32 group;
964 int failure;
965 int delivery_failure;
966 int congested;
967 int delivered;
968 gfp_t allocation;
969 struct sk_buff *skb, *skb2;
970 };
971
972 static inline int do_one_broadcast(struct sock *sk,
973 struct netlink_broadcast_data *p)
974 {
975 struct netlink_sock *nlk = nlk_sk(sk);
976 int val;
977
978 if (p->exclude_sk == sk)
979 goto out;
980
981 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
982 !test_bit(p->group - 1, nlk->groups))
983 goto out;
984
985 if (!net_eq(sock_net(sk), p->net))
986 goto out;
987
988 if (p->failure) {
989 netlink_overrun(sk);
990 goto out;
991 }
992
993 sock_hold(sk);
994 if (p->skb2 == NULL) {
995 if (skb_shared(p->skb)) {
996 p->skb2 = skb_clone(p->skb, p->allocation);
997 } else {
998 p->skb2 = skb_get(p->skb);
999 /*
1000 * skb ownership may have been set when
1001 * delivered to a previous socket.
1002 */
1003 skb_orphan(p->skb2);
1004 }
1005 }
1006 if (p->skb2 == NULL) {
1007 netlink_overrun(sk);
1008 /* Clone failed. Notify ALL listeners. */
1009 p->failure = 1;
1010 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1011 p->delivery_failure = 1;
1012 } else if (sk_filter(sk, p->skb2)) {
1013 kfree_skb(p->skb2);
1014 p->skb2 = NULL;
1015 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1016 netlink_overrun(sk);
1017 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1018 p->delivery_failure = 1;
1019 } else {
1020 p->congested |= val;
1021 p->delivered = 1;
1022 p->skb2 = NULL;
1023 }
1024 sock_put(sk);
1025
1026 out:
1027 return 0;
1028 }
1029
1030 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
1031 u32 group, gfp_t allocation)
1032 {
1033 struct net *net = sock_net(ssk);
1034 struct netlink_broadcast_data info;
1035 struct hlist_node *node;
1036 struct sock *sk;
1037
1038 skb = netlink_trim(skb, allocation);
1039
1040 info.exclude_sk = ssk;
1041 info.net = net;
1042 info.pid = pid;
1043 info.group = group;
1044 info.failure = 0;
1045 info.delivery_failure = 0;
1046 info.congested = 0;
1047 info.delivered = 0;
1048 info.allocation = allocation;
1049 info.skb = skb;
1050 info.skb2 = NULL;
1051
1052 /* While we sleep in clone, do not allow to change socket list */
1053
1054 netlink_lock_table();
1055
1056 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1057 do_one_broadcast(sk, &info);
1058
1059 kfree_skb(skb);
1060
1061 netlink_unlock_table();
1062
1063 kfree_skb(info.skb2);
1064
1065 if (info.delivery_failure)
1066 return -ENOBUFS;
1067
1068 if (info.delivered) {
1069 if (info.congested && (allocation & __GFP_WAIT))
1070 yield();
1071 return 0;
1072 }
1073 return -ESRCH;
1074 }
1075 EXPORT_SYMBOL(netlink_broadcast);
1076
1077 struct netlink_set_err_data {
1078 struct sock *exclude_sk;
1079 u32 pid;
1080 u32 group;
1081 int code;
1082 };
1083
1084 static inline int do_one_set_err(struct sock *sk,
1085 struct netlink_set_err_data *p)
1086 {
1087 struct netlink_sock *nlk = nlk_sk(sk);
1088
1089 if (sk == p->exclude_sk)
1090 goto out;
1091
1092 if (sock_net(sk) != sock_net(p->exclude_sk))
1093 goto out;
1094
1095 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1096 !test_bit(p->group - 1, nlk->groups))
1097 goto out;
1098
1099 sk->sk_err = p->code;
1100 sk->sk_error_report(sk);
1101 out:
1102 return 0;
1103 }
1104
1105 /**
1106 * netlink_set_err - report error to broadcast listeners
1107 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1108 * @pid: the PID of a process that we want to skip (if any)
1109 * @groups: the broadcast group that will notice the error
1110 * @code: error code, must be negative (as usual in kernelspace)
1111 */
1112 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1113 {
1114 struct netlink_set_err_data info;
1115 struct hlist_node *node;
1116 struct sock *sk;
1117
1118 info.exclude_sk = ssk;
1119 info.pid = pid;
1120 info.group = group;
1121 /* sk->sk_err wants a positive error value */
1122 info.code = -code;
1123
1124 read_lock(&nl_table_lock);
1125
1126 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1127 do_one_set_err(sk, &info);
1128
1129 read_unlock(&nl_table_lock);
1130 }
1131 EXPORT_SYMBOL(netlink_set_err);
1132
1133 /* must be called with netlink table grabbed */
1134 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1135 unsigned int group,
1136 int is_new)
1137 {
1138 int old, new = !!is_new, subscriptions;
1139
1140 old = test_bit(group - 1, nlk->groups);
1141 subscriptions = nlk->subscriptions - old + new;
1142 if (new)
1143 __set_bit(group - 1, nlk->groups);
1144 else
1145 __clear_bit(group - 1, nlk->groups);
1146 netlink_update_subscriptions(&nlk->sk, subscriptions);
1147 netlink_update_listeners(&nlk->sk);
1148 }
1149
1150 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1151 char __user *optval, int optlen)
1152 {
1153 struct sock *sk = sock->sk;
1154 struct netlink_sock *nlk = nlk_sk(sk);
1155 unsigned int val = 0;
1156 int err;
1157
1158 if (level != SOL_NETLINK)
1159 return -ENOPROTOOPT;
1160
1161 if (optlen >= sizeof(int) &&
1162 get_user(val, (unsigned int __user *)optval))
1163 return -EFAULT;
1164
1165 switch (optname) {
1166 case NETLINK_PKTINFO:
1167 if (val)
1168 nlk->flags |= NETLINK_RECV_PKTINFO;
1169 else
1170 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1171 err = 0;
1172 break;
1173 case NETLINK_ADD_MEMBERSHIP:
1174 case NETLINK_DROP_MEMBERSHIP: {
1175 if (!netlink_capable(sock, NL_NONROOT_RECV))
1176 return -EPERM;
1177 err = netlink_realloc_groups(sk);
1178 if (err)
1179 return err;
1180 if (!val || val - 1 >= nlk->ngroups)
1181 return -EINVAL;
1182 netlink_table_grab();
1183 netlink_update_socket_mc(nlk, val,
1184 optname == NETLINK_ADD_MEMBERSHIP);
1185 netlink_table_ungrab();
1186 err = 0;
1187 break;
1188 }
1189 case NETLINK_BROADCAST_ERROR:
1190 if (val)
1191 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1192 else
1193 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1194 err = 0;
1195 break;
1196 case NETLINK_NO_ENOBUFS:
1197 if (val) {
1198 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1199 clear_bit(0, &nlk->state);
1200 wake_up_interruptible(&nlk->wait);
1201 } else
1202 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1203 err = 0;
1204 break;
1205 default:
1206 err = -ENOPROTOOPT;
1207 }
1208 return err;
1209 }
1210
1211 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1212 char __user *optval, int __user *optlen)
1213 {
1214 struct sock *sk = sock->sk;
1215 struct netlink_sock *nlk = nlk_sk(sk);
1216 int len, val, err;
1217
1218 if (level != SOL_NETLINK)
1219 return -ENOPROTOOPT;
1220
1221 if (get_user(len, optlen))
1222 return -EFAULT;
1223 if (len < 0)
1224 return -EINVAL;
1225
1226 switch (optname) {
1227 case NETLINK_PKTINFO:
1228 if (len < sizeof(int))
1229 return -EINVAL;
1230 len = sizeof(int);
1231 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1232 if (put_user(len, optlen) ||
1233 put_user(val, optval))
1234 return -EFAULT;
1235 err = 0;
1236 break;
1237 case NETLINK_BROADCAST_ERROR:
1238 if (len < sizeof(int))
1239 return -EINVAL;
1240 len = sizeof(int);
1241 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1242 if (put_user(len, optlen) ||
1243 put_user(val, optval))
1244 return -EFAULT;
1245 err = 0;
1246 break;
1247 case NETLINK_NO_ENOBUFS:
1248 if (len < sizeof(int))
1249 return -EINVAL;
1250 len = sizeof(int);
1251 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1252 if (put_user(len, optlen) ||
1253 put_user(val, optval))
1254 return -EFAULT;
1255 err = 0;
1256 break;
1257 default:
1258 err = -ENOPROTOOPT;
1259 }
1260 return err;
1261 }
1262
1263 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1264 {
1265 struct nl_pktinfo info;
1266
1267 info.group = NETLINK_CB(skb).dst_group;
1268 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1269 }
1270
1271 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1272 struct msghdr *msg, size_t len)
1273 {
1274 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1275 struct sock *sk = sock->sk;
1276 struct netlink_sock *nlk = nlk_sk(sk);
1277 struct sockaddr_nl *addr = msg->msg_name;
1278 u32 dst_pid;
1279 u32 dst_group;
1280 struct sk_buff *skb;
1281 int err;
1282 struct scm_cookie scm;
1283
1284 if (msg->msg_flags&MSG_OOB)
1285 return -EOPNOTSUPP;
1286
1287 if (NULL == siocb->scm)
1288 siocb->scm = &scm;
1289 err = scm_send(sock, msg, siocb->scm);
1290 if (err < 0)
1291 return err;
1292
1293 if (msg->msg_namelen) {
1294 if (addr->nl_family != AF_NETLINK)
1295 return -EINVAL;
1296 dst_pid = addr->nl_pid;
1297 dst_group = ffs(addr->nl_groups);
1298 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1299 return -EPERM;
1300 } else {
1301 dst_pid = nlk->dst_pid;
1302 dst_group = nlk->dst_group;
1303 }
1304
1305 if (!nlk->pid) {
1306 err = netlink_autobind(sock);
1307 if (err)
1308 goto out;
1309 }
1310
1311 err = -EMSGSIZE;
1312 if (len > sk->sk_sndbuf - 32)
1313 goto out;
1314 err = -ENOBUFS;
1315 skb = alloc_skb(len, GFP_KERNEL);
1316 if (skb == NULL)
1317 goto out;
1318
1319 NETLINK_CB(skb).pid = nlk->pid;
1320 NETLINK_CB(skb).dst_group = dst_group;
1321 NETLINK_CB(skb).loginuid = audit_get_loginuid(current);
1322 NETLINK_CB(skb).sessionid = audit_get_sessionid(current);
1323 security_task_getsecid(current, &(NETLINK_CB(skb).sid));
1324 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1325
1326 /* What can I do? Netlink is asynchronous, so that
1327 we will have to save current capabilities to
1328 check them, when this message will be delivered
1329 to corresponding kernel module. --ANK (980802)
1330 */
1331
1332 err = -EFAULT;
1333 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1334 kfree_skb(skb);
1335 goto out;
1336 }
1337
1338 err = security_netlink_send(sk, skb);
1339 if (err) {
1340 kfree_skb(skb);
1341 goto out;
1342 }
1343
1344 if (dst_group) {
1345 atomic_inc(&skb->users);
1346 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1347 }
1348 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1349
1350 out:
1351 return err;
1352 }
1353
1354 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1355 struct msghdr *msg, size_t len,
1356 int flags)
1357 {
1358 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1359 struct scm_cookie scm;
1360 struct sock *sk = sock->sk;
1361 struct netlink_sock *nlk = nlk_sk(sk);
1362 int noblock = flags&MSG_DONTWAIT;
1363 size_t copied;
1364 struct sk_buff *skb, *frag __maybe_unused = NULL;
1365 int err;
1366
1367 if (flags&MSG_OOB)
1368 return -EOPNOTSUPP;
1369
1370 copied = 0;
1371
1372 skb = skb_recv_datagram(sk, flags, noblock, &err);
1373 if (skb == NULL)
1374 goto out;
1375
1376 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1377 if (unlikely(skb_shinfo(skb)->frag_list)) {
1378 bool need_compat = !!(flags & MSG_CMSG_COMPAT);
1379
1380 /*
1381 * If this skb has a frag_list, then here that means that
1382 * we will have to use the frag_list skb for compat tasks
1383 * and the regular skb for non-compat tasks.
1384 *
1385 * The skb might (and likely will) be cloned, so we can't
1386 * just reset frag_list and go on with things -- we need to
1387 * keep that. For the compat case that's easy -- simply get
1388 * a reference to the compat skb and free the regular one
1389 * including the frag. For the non-compat case, we need to
1390 * avoid sending the frag to the user -- so assign NULL but
1391 * restore it below before freeing the skb.
1392 */
1393 if (need_compat) {
1394 struct sk_buff *compskb = skb_shinfo(skb)->frag_list;
1395 skb_get(compskb);
1396 kfree_skb(skb);
1397 skb = compskb;
1398 } else {
1399 frag = skb_shinfo(skb)->frag_list;
1400 skb_shinfo(skb)->frag_list = NULL;
1401 }
1402 }
1403 #endif
1404
1405 msg->msg_namelen = 0;
1406
1407 copied = skb->len;
1408 if (len < copied) {
1409 msg->msg_flags |= MSG_TRUNC;
1410 copied = len;
1411 }
1412
1413 skb_reset_transport_header(skb);
1414 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1415
1416 if (msg->msg_name) {
1417 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1418 addr->nl_family = AF_NETLINK;
1419 addr->nl_pad = 0;
1420 addr->nl_pid = NETLINK_CB(skb).pid;
1421 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1422 msg->msg_namelen = sizeof(*addr);
1423 }
1424
1425 if (nlk->flags & NETLINK_RECV_PKTINFO)
1426 netlink_cmsg_recv_pktinfo(msg, skb);
1427
1428 if (NULL == siocb->scm) {
1429 memset(&scm, 0, sizeof(scm));
1430 siocb->scm = &scm;
1431 }
1432 siocb->scm->creds = *NETLINK_CREDS(skb);
1433 if (flags & MSG_TRUNC)
1434 copied = skb->len;
1435
1436 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1437 skb_shinfo(skb)->frag_list = frag;
1438 #endif
1439
1440 skb_free_datagram(sk, skb);
1441
1442 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1443 netlink_dump(sk);
1444
1445 scm_recv(sock, msg, siocb->scm, flags);
1446 out:
1447 netlink_rcv_wake(sk);
1448 return err ? : copied;
1449 }
1450
1451 static void netlink_data_ready(struct sock *sk, int len)
1452 {
1453 BUG();
1454 }
1455
1456 /*
1457 * We export these functions to other modules. They provide a
1458 * complete set of kernel non-blocking support for message
1459 * queueing.
1460 */
1461
1462 struct sock *
1463 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1464 void (*input)(struct sk_buff *skb),
1465 struct mutex *cb_mutex, struct module *module)
1466 {
1467 struct socket *sock;
1468 struct sock *sk;
1469 struct netlink_sock *nlk;
1470 unsigned long *listeners = NULL;
1471
1472 BUG_ON(!nl_table);
1473
1474 if (unit < 0 || unit >= MAX_LINKS)
1475 return NULL;
1476
1477 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1478 return NULL;
1479
1480 /*
1481 * We have to just have a reference on the net from sk, but don't
1482 * get_net it. Besides, we cannot get and then put the net here.
1483 * So we create one inside init_net and the move it to net.
1484 */
1485
1486 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1487 goto out_sock_release_nosk;
1488
1489 sk = sock->sk;
1490 sk_change_net(sk, net);
1491
1492 if (groups < 32)
1493 groups = 32;
1494
1495 listeners = kzalloc(NLGRPSZ(groups) + sizeof(struct listeners_rcu_head),
1496 GFP_KERNEL);
1497 if (!listeners)
1498 goto out_sock_release;
1499
1500 sk->sk_data_ready = netlink_data_ready;
1501 if (input)
1502 nlk_sk(sk)->netlink_rcv = input;
1503
1504 if (netlink_insert(sk, net, 0))
1505 goto out_sock_release;
1506
1507 nlk = nlk_sk(sk);
1508 nlk->flags |= NETLINK_KERNEL_SOCKET;
1509
1510 netlink_table_grab();
1511 if (!nl_table[unit].registered) {
1512 nl_table[unit].groups = groups;
1513 nl_table[unit].listeners = listeners;
1514 nl_table[unit].cb_mutex = cb_mutex;
1515 nl_table[unit].module = module;
1516 nl_table[unit].registered = 1;
1517 } else {
1518 kfree(listeners);
1519 nl_table[unit].registered++;
1520 }
1521 netlink_table_ungrab();
1522 return sk;
1523
1524 out_sock_release:
1525 kfree(listeners);
1526 netlink_kernel_release(sk);
1527 return NULL;
1528
1529 out_sock_release_nosk:
1530 sock_release(sock);
1531 return NULL;
1532 }
1533 EXPORT_SYMBOL(netlink_kernel_create);
1534
1535
1536 void
1537 netlink_kernel_release(struct sock *sk)
1538 {
1539 sk_release_kernel(sk);
1540 }
1541 EXPORT_SYMBOL(netlink_kernel_release);
1542
1543
1544 static void netlink_free_old_listeners(struct rcu_head *rcu_head)
1545 {
1546 struct listeners_rcu_head *lrh;
1547
1548 lrh = container_of(rcu_head, struct listeners_rcu_head, rcu_head);
1549 kfree(lrh->ptr);
1550 }
1551
1552 /**
1553 * netlink_change_ngroups - change number of multicast groups
1554 *
1555 * This changes the number of multicast groups that are available
1556 * on a certain netlink family. Note that it is not possible to
1557 * change the number of groups to below 32. Also note that it does
1558 * not implicitly call netlink_clear_multicast_users() when the
1559 * number of groups is reduced.
1560 *
1561 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1562 * @groups: The new number of groups.
1563 */
1564 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1565 {
1566 unsigned long *listeners, *old = NULL;
1567 struct listeners_rcu_head *old_rcu_head;
1568 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1569 int err = 0;
1570
1571 if (groups < 32)
1572 groups = 32;
1573
1574 netlink_table_grab();
1575 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1576 listeners = kzalloc(NLGRPSZ(groups) +
1577 sizeof(struct listeners_rcu_head),
1578 GFP_ATOMIC);
1579 if (!listeners) {
1580 err = -ENOMEM;
1581 goto out_ungrab;
1582 }
1583 old = tbl->listeners;
1584 memcpy(listeners, old, NLGRPSZ(tbl->groups));
1585 rcu_assign_pointer(tbl->listeners, listeners);
1586 /*
1587 * Free the old memory after an RCU grace period so we
1588 * don't leak it. We use call_rcu() here in order to be
1589 * able to call this function from atomic contexts. The
1590 * allocation of this memory will have reserved enough
1591 * space for struct listeners_rcu_head at the end.
1592 */
1593 old_rcu_head = (void *)(tbl->listeners +
1594 NLGRPLONGS(tbl->groups));
1595 old_rcu_head->ptr = old;
1596 call_rcu(&old_rcu_head->rcu_head, netlink_free_old_listeners);
1597 }
1598 tbl->groups = groups;
1599
1600 out_ungrab:
1601 netlink_table_ungrab();
1602 return err;
1603 }
1604
1605 /**
1606 * netlink_clear_multicast_users - kick off multicast listeners
1607 *
1608 * This function removes all listeners from the given group.
1609 * @ksk: The kernel netlink socket, as returned by
1610 * netlink_kernel_create().
1611 * @group: The multicast group to clear.
1612 */
1613 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1614 {
1615 struct sock *sk;
1616 struct hlist_node *node;
1617 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1618
1619 netlink_table_grab();
1620
1621 sk_for_each_bound(sk, node, &tbl->mc_list)
1622 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1623
1624 netlink_table_ungrab();
1625 }
1626
1627 void netlink_set_nonroot(int protocol, unsigned int flags)
1628 {
1629 if ((unsigned int)protocol < MAX_LINKS)
1630 nl_table[protocol].nl_nonroot = flags;
1631 }
1632 EXPORT_SYMBOL(netlink_set_nonroot);
1633
1634 static void netlink_destroy_callback(struct netlink_callback *cb)
1635 {
1636 kfree_skb(cb->skb);
1637 kfree(cb);
1638 }
1639
1640 /*
1641 * It looks a bit ugly.
1642 * It would be better to create kernel thread.
1643 */
1644
1645 static int netlink_dump(struct sock *sk)
1646 {
1647 struct netlink_sock *nlk = nlk_sk(sk);
1648 struct netlink_callback *cb;
1649 struct sk_buff *skb;
1650 struct nlmsghdr *nlh;
1651 int len, err = -ENOBUFS;
1652
1653 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1654 if (!skb)
1655 goto errout;
1656
1657 mutex_lock(nlk->cb_mutex);
1658
1659 cb = nlk->cb;
1660 if (cb == NULL) {
1661 err = -EINVAL;
1662 goto errout_skb;
1663 }
1664
1665 len = cb->dump(skb, cb);
1666
1667 if (len > 0) {
1668 mutex_unlock(nlk->cb_mutex);
1669
1670 if (sk_filter(sk, skb))
1671 kfree_skb(skb);
1672 else {
1673 skb_queue_tail(&sk->sk_receive_queue, skb);
1674 sk->sk_data_ready(sk, skb->len);
1675 }
1676 return 0;
1677 }
1678
1679 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1680 if (!nlh)
1681 goto errout_skb;
1682
1683 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1684
1685 if (sk_filter(sk, skb))
1686 kfree_skb(skb);
1687 else {
1688 skb_queue_tail(&sk->sk_receive_queue, skb);
1689 sk->sk_data_ready(sk, skb->len);
1690 }
1691
1692 if (cb->done)
1693 cb->done(cb);
1694 nlk->cb = NULL;
1695 mutex_unlock(nlk->cb_mutex);
1696
1697 netlink_destroy_callback(cb);
1698 return 0;
1699
1700 errout_skb:
1701 mutex_unlock(nlk->cb_mutex);
1702 kfree_skb(skb);
1703 errout:
1704 return err;
1705 }
1706
1707 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1708 const struct nlmsghdr *nlh,
1709 int (*dump)(struct sk_buff *skb,
1710 struct netlink_callback *),
1711 int (*done)(struct netlink_callback *))
1712 {
1713 struct netlink_callback *cb;
1714 struct sock *sk;
1715 struct netlink_sock *nlk;
1716
1717 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1718 if (cb == NULL)
1719 return -ENOBUFS;
1720
1721 cb->dump = dump;
1722 cb->done = done;
1723 cb->nlh = nlh;
1724 atomic_inc(&skb->users);
1725 cb->skb = skb;
1726
1727 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1728 if (sk == NULL) {
1729 netlink_destroy_callback(cb);
1730 return -ECONNREFUSED;
1731 }
1732 nlk = nlk_sk(sk);
1733 /* A dump is in progress... */
1734 mutex_lock(nlk->cb_mutex);
1735 if (nlk->cb) {
1736 mutex_unlock(nlk->cb_mutex);
1737 netlink_destroy_callback(cb);
1738 sock_put(sk);
1739 return -EBUSY;
1740 }
1741 nlk->cb = cb;
1742 mutex_unlock(nlk->cb_mutex);
1743
1744 netlink_dump(sk);
1745 sock_put(sk);
1746
1747 /* We successfully started a dump, by returning -EINTR we
1748 * signal not to send ACK even if it was requested.
1749 */
1750 return -EINTR;
1751 }
1752 EXPORT_SYMBOL(netlink_dump_start);
1753
1754 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1755 {
1756 struct sk_buff *skb;
1757 struct nlmsghdr *rep;
1758 struct nlmsgerr *errmsg;
1759 size_t payload = sizeof(*errmsg);
1760
1761 /* error messages get the original request appened */
1762 if (err)
1763 payload += nlmsg_len(nlh);
1764
1765 skb = nlmsg_new(payload, GFP_KERNEL);
1766 if (!skb) {
1767 struct sock *sk;
1768
1769 sk = netlink_lookup(sock_net(in_skb->sk),
1770 in_skb->sk->sk_protocol,
1771 NETLINK_CB(in_skb).pid);
1772 if (sk) {
1773 sk->sk_err = ENOBUFS;
1774 sk->sk_error_report(sk);
1775 sock_put(sk);
1776 }
1777 return;
1778 }
1779
1780 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1781 NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
1782 errmsg = nlmsg_data(rep);
1783 errmsg->error = err;
1784 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1785 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1786 }
1787 EXPORT_SYMBOL(netlink_ack);
1788
1789 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1790 struct nlmsghdr *))
1791 {
1792 struct nlmsghdr *nlh;
1793 int err;
1794
1795 while (skb->len >= nlmsg_total_size(0)) {
1796 int msglen;
1797
1798 nlh = nlmsg_hdr(skb);
1799 err = 0;
1800
1801 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1802 return 0;
1803
1804 /* Only requests are handled by the kernel */
1805 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1806 goto ack;
1807
1808 /* Skip control messages */
1809 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1810 goto ack;
1811
1812 err = cb(skb, nlh);
1813 if (err == -EINTR)
1814 goto skip;
1815
1816 ack:
1817 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1818 netlink_ack(skb, nlh, err);
1819
1820 skip:
1821 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1822 if (msglen > skb->len)
1823 msglen = skb->len;
1824 skb_pull(skb, msglen);
1825 }
1826
1827 return 0;
1828 }
1829 EXPORT_SYMBOL(netlink_rcv_skb);
1830
1831 /**
1832 * nlmsg_notify - send a notification netlink message
1833 * @sk: netlink socket to use
1834 * @skb: notification message
1835 * @pid: destination netlink pid for reports or 0
1836 * @group: destination multicast group or 0
1837 * @report: 1 to report back, 0 to disable
1838 * @flags: allocation flags
1839 */
1840 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1841 unsigned int group, int report, gfp_t flags)
1842 {
1843 int err = 0;
1844
1845 if (group) {
1846 int exclude_pid = 0;
1847
1848 if (report) {
1849 atomic_inc(&skb->users);
1850 exclude_pid = pid;
1851 }
1852
1853 /* errors reported via destination sk->sk_err, but propagate
1854 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1855 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1856 }
1857
1858 if (report) {
1859 int err2;
1860
1861 err2 = nlmsg_unicast(sk, skb, pid);
1862 if (!err || err == -ESRCH)
1863 err = err2;
1864 }
1865
1866 return err;
1867 }
1868 EXPORT_SYMBOL(nlmsg_notify);
1869
1870 #ifdef CONFIG_PROC_FS
1871 struct nl_seq_iter {
1872 struct seq_net_private p;
1873 int link;
1874 int hash_idx;
1875 };
1876
1877 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1878 {
1879 struct nl_seq_iter *iter = seq->private;
1880 int i, j;
1881 struct sock *s;
1882 struct hlist_node *node;
1883 loff_t off = 0;
1884
1885 for (i = 0; i < MAX_LINKS; i++) {
1886 struct nl_pid_hash *hash = &nl_table[i].hash;
1887
1888 for (j = 0; j <= hash->mask; j++) {
1889 sk_for_each(s, node, &hash->table[j]) {
1890 if (sock_net(s) != seq_file_net(seq))
1891 continue;
1892 if (off == pos) {
1893 iter->link = i;
1894 iter->hash_idx = j;
1895 return s;
1896 }
1897 ++off;
1898 }
1899 }
1900 }
1901 return NULL;
1902 }
1903
1904 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1905 __acquires(nl_table_lock)
1906 {
1907 read_lock(&nl_table_lock);
1908 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1909 }
1910
1911 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1912 {
1913 struct sock *s;
1914 struct nl_seq_iter *iter;
1915 int i, j;
1916
1917 ++*pos;
1918
1919 if (v == SEQ_START_TOKEN)
1920 return netlink_seq_socket_idx(seq, 0);
1921
1922 iter = seq->private;
1923 s = v;
1924 do {
1925 s = sk_next(s);
1926 } while (s && sock_net(s) != seq_file_net(seq));
1927 if (s)
1928 return s;
1929
1930 i = iter->link;
1931 j = iter->hash_idx + 1;
1932
1933 do {
1934 struct nl_pid_hash *hash = &nl_table[i].hash;
1935
1936 for (; j <= hash->mask; j++) {
1937 s = sk_head(&hash->table[j]);
1938 while (s && sock_net(s) != seq_file_net(seq))
1939 s = sk_next(s);
1940 if (s) {
1941 iter->link = i;
1942 iter->hash_idx = j;
1943 return s;
1944 }
1945 }
1946
1947 j = 0;
1948 } while (++i < MAX_LINKS);
1949
1950 return NULL;
1951 }
1952
1953 static void netlink_seq_stop(struct seq_file *seq, void *v)
1954 __releases(nl_table_lock)
1955 {
1956 read_unlock(&nl_table_lock);
1957 }
1958
1959
1960 static int netlink_seq_show(struct seq_file *seq, void *v)
1961 {
1962 if (v == SEQ_START_TOKEN)
1963 seq_puts(seq,
1964 "sk Eth Pid Groups "
1965 "Rmem Wmem Dump Locks Drops\n");
1966 else {
1967 struct sock *s = v;
1968 struct netlink_sock *nlk = nlk_sk(s);
1969
1970 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %-8d %-8d\n",
1971 s,
1972 s->sk_protocol,
1973 nlk->pid,
1974 nlk->groups ? (u32)nlk->groups[0] : 0,
1975 sk_rmem_alloc_get(s),
1976 sk_wmem_alloc_get(s),
1977 nlk->cb,
1978 atomic_read(&s->sk_refcnt),
1979 atomic_read(&s->sk_drops)
1980 );
1981
1982 }
1983 return 0;
1984 }
1985
1986 static const struct seq_operations netlink_seq_ops = {
1987 .start = netlink_seq_start,
1988 .next = netlink_seq_next,
1989 .stop = netlink_seq_stop,
1990 .show = netlink_seq_show,
1991 };
1992
1993
1994 static int netlink_seq_open(struct inode *inode, struct file *file)
1995 {
1996 return seq_open_net(inode, file, &netlink_seq_ops,
1997 sizeof(struct nl_seq_iter));
1998 }
1999
2000 static const struct file_operations netlink_seq_fops = {
2001 .owner = THIS_MODULE,
2002 .open = netlink_seq_open,
2003 .read = seq_read,
2004 .llseek = seq_lseek,
2005 .release = seq_release_net,
2006 };
2007
2008 #endif
2009
2010 int netlink_register_notifier(struct notifier_block *nb)
2011 {
2012 return atomic_notifier_chain_register(&netlink_chain, nb);
2013 }
2014 EXPORT_SYMBOL(netlink_register_notifier);
2015
2016 int netlink_unregister_notifier(struct notifier_block *nb)
2017 {
2018 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2019 }
2020 EXPORT_SYMBOL(netlink_unregister_notifier);
2021
2022 static const struct proto_ops netlink_ops = {
2023 .family = PF_NETLINK,
2024 .owner = THIS_MODULE,
2025 .release = netlink_release,
2026 .bind = netlink_bind,
2027 .connect = netlink_connect,
2028 .socketpair = sock_no_socketpair,
2029 .accept = sock_no_accept,
2030 .getname = netlink_getname,
2031 .poll = datagram_poll,
2032 .ioctl = sock_no_ioctl,
2033 .listen = sock_no_listen,
2034 .shutdown = sock_no_shutdown,
2035 .setsockopt = netlink_setsockopt,
2036 .getsockopt = netlink_getsockopt,
2037 .sendmsg = netlink_sendmsg,
2038 .recvmsg = netlink_recvmsg,
2039 .mmap = sock_no_mmap,
2040 .sendpage = sock_no_sendpage,
2041 };
2042
2043 static struct net_proto_family netlink_family_ops = {
2044 .family = PF_NETLINK,
2045 .create = netlink_create,
2046 .owner = THIS_MODULE, /* for consistency 8) */
2047 };
2048
2049 static int __net_init netlink_net_init(struct net *net)
2050 {
2051 #ifdef CONFIG_PROC_FS
2052 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2053 return -ENOMEM;
2054 #endif
2055 return 0;
2056 }
2057
2058 static void __net_exit netlink_net_exit(struct net *net)
2059 {
2060 #ifdef CONFIG_PROC_FS
2061 proc_net_remove(net, "netlink");
2062 #endif
2063 }
2064
2065 static struct pernet_operations __net_initdata netlink_net_ops = {
2066 .init = netlink_net_init,
2067 .exit = netlink_net_exit,
2068 };
2069
2070 static int __init netlink_proto_init(void)
2071 {
2072 struct sk_buff *dummy_skb;
2073 int i;
2074 unsigned long limit;
2075 unsigned int order;
2076 int err = proto_register(&netlink_proto, 0);
2077
2078 if (err != 0)
2079 goto out;
2080
2081 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2082
2083 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2084 if (!nl_table)
2085 goto panic;
2086
2087 if (num_physpages >= (128 * 1024))
2088 limit = num_physpages >> (21 - PAGE_SHIFT);
2089 else
2090 limit = num_physpages >> (23 - PAGE_SHIFT);
2091
2092 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2093 limit = (1UL << order) / sizeof(struct hlist_head);
2094 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2095
2096 for (i = 0; i < MAX_LINKS; i++) {
2097 struct nl_pid_hash *hash = &nl_table[i].hash;
2098
2099 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
2100 if (!hash->table) {
2101 while (i-- > 0)
2102 nl_pid_hash_free(nl_table[i].hash.table,
2103 1 * sizeof(*hash->table));
2104 kfree(nl_table);
2105 goto panic;
2106 }
2107 hash->max_shift = order;
2108 hash->shift = 0;
2109 hash->mask = 0;
2110 hash->rehash_time = jiffies;
2111 }
2112
2113 sock_register(&netlink_family_ops);
2114 register_pernet_subsys(&netlink_net_ops);
2115 /* The netlink device handler may be needed early. */
2116 rtnetlink_init();
2117 out:
2118 return err;
2119 panic:
2120 panic("netlink_init: Cannot allocate nl_table\n");
2121 }
2122
2123 core_initcall(netlink_proto_init);
Linux with added FPC-III support