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[SK_BUFF]: Convert skb->end to sk_buff_data_t
[linux-2.6/openmoko-kernel.git] / net / netlink / af_netlink.c
blob50dc5edb7752308f896c87976f5b64052cc9c451
1 /*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@redhat.com>
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/smp_lock.h>
49 #include <linux/notifier.h>
50 #include <linux/security.h>
51 #include <linux/jhash.h>
52 #include <linux/jiffies.h>
53 #include <linux/random.h>
54 #include <linux/bitops.h>
55 #include <linux/mm.h>
56 #include <linux/types.h>
57 #include <linux/audit.h>
58 #include <linux/selinux.h>
59
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
66 struct netlink_sock {
67 /* struct sock has to be the first member of netlink_sock */
68 struct sock sk;
69 u32 pid;
70 u32 dst_pid;
71 u32 dst_group;
72 u32 flags;
73 u32 subscriptions;
74 u32 ngroups;
75 unsigned long *groups;
76 unsigned long state;
77 wait_queue_head_t wait;
78 struct netlink_callback *cb;
79 spinlock_t cb_lock;
80 void (*data_ready)(struct sock *sk, int bytes);
81 struct module *module;
82 };
83
84 #define NETLINK_KERNEL_SOCKET 0x1
85 #define NETLINK_RECV_PKTINFO 0x2
86
87 static inline struct netlink_sock *nlk_sk(struct sock *sk)
88 {
89 return (struct netlink_sock *)sk;
90 }
91
92 struct nl_pid_hash {
93 struct hlist_head *table;
94 unsigned long rehash_time;
95
96 unsigned int mask;
97 unsigned int shift;
98
99 unsigned int entries;
100 unsigned int max_shift;
101
102 u32 rnd;
103 };
104
105 struct netlink_table {
106 struct nl_pid_hash hash;
107 struct hlist_head mc_list;
108 unsigned long *listeners;
109 unsigned int nl_nonroot;
110 unsigned int groups;
111 struct module *module;
112 int registered;
113 };
114
115 static struct netlink_table *nl_table;
116
117 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
118
119 static int netlink_dump(struct sock *sk);
120 static void netlink_destroy_callback(struct netlink_callback *cb);
121
122 static DEFINE_RWLOCK(nl_table_lock);
123 static atomic_t nl_table_users = ATOMIC_INIT(0);
124
125 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
126
127 static u32 netlink_group_mask(u32 group)
128 {
129 return group ? 1 << (group - 1) : 0;
130 }
131
132 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
133 {
134 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
135 }
136
137 static void netlink_sock_destruct(struct sock *sk)
138 {
139 skb_queue_purge(&sk->sk_receive_queue);
140
141 if (!sock_flag(sk, SOCK_DEAD)) {
142 printk("Freeing alive netlink socket %p\n", sk);
143 return;
144 }
145 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
146 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
147 BUG_TRAP(!nlk_sk(sk)->cb);
148 BUG_TRAP(!nlk_sk(sk)->groups);
149 }
150
151 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
152 * Look, when several writers sleep and reader wakes them up, all but one
153 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
154 * this, _but_ remember, it adds useless work on UP machines.
155 */
156
157 static void netlink_table_grab(void)
158 {
159 write_lock_irq(&nl_table_lock);
160
161 if (atomic_read(&nl_table_users)) {
162 DECLARE_WAITQUEUE(wait, current);
163
164 add_wait_queue_exclusive(&nl_table_wait, &wait);
165 for(;;) {
166 set_current_state(TASK_UNINTERRUPTIBLE);
167 if (atomic_read(&nl_table_users) == 0)
168 break;
169 write_unlock_irq(&nl_table_lock);
170 schedule();
171 write_lock_irq(&nl_table_lock);
172 }
173
174 __set_current_state(TASK_RUNNING);
175 remove_wait_queue(&nl_table_wait, &wait);
176 }
177 }
178
179 static __inline__ void netlink_table_ungrab(void)
180 {
181 write_unlock_irq(&nl_table_lock);
182 wake_up(&nl_table_wait);
183 }
184
185 static __inline__ void
186 netlink_lock_table(void)
187 {
188 /* read_lock() synchronizes us to netlink_table_grab */
189
190 read_lock(&nl_table_lock);
191 atomic_inc(&nl_table_users);
192 read_unlock(&nl_table_lock);
193 }
194
195 static __inline__ void
196 netlink_unlock_table(void)
197 {
198 if (atomic_dec_and_test(&nl_table_users))
199 wake_up(&nl_table_wait);
200 }
201
202 static __inline__ struct sock *netlink_lookup(int protocol, u32 pid)
203 {
204 struct nl_pid_hash *hash = &nl_table[protocol].hash;
205 struct hlist_head *head;
206 struct sock *sk;
207 struct hlist_node *node;
208
209 read_lock(&nl_table_lock);
210 head = nl_pid_hashfn(hash, pid);
211 sk_for_each(sk, node, head) {
212 if (nlk_sk(sk)->pid == pid) {
213 sock_hold(sk);
214 goto found;
215 }
216 }
217 sk = NULL;
218 found:
219 read_unlock(&nl_table_lock);
220 return sk;
221 }
222
223 static inline struct hlist_head *nl_pid_hash_alloc(size_t size)
224 {
225 if (size <= PAGE_SIZE)
226 return kmalloc(size, GFP_ATOMIC);
227 else
228 return (struct hlist_head *)
229 __get_free_pages(GFP_ATOMIC, get_order(size));
230 }
231
232 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
233 {
234 if (size <= PAGE_SIZE)
235 kfree(table);
236 else
237 free_pages((unsigned long)table, get_order(size));
238 }
239
240 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
241 {
242 unsigned int omask, mask, shift;
243 size_t osize, size;
244 struct hlist_head *otable, *table;
245 int i;
246
247 omask = mask = hash->mask;
248 osize = size = (mask + 1) * sizeof(*table);
249 shift = hash->shift;
250
251 if (grow) {
252 if (++shift > hash->max_shift)
253 return 0;
254 mask = mask * 2 + 1;
255 size *= 2;
256 }
257
258 table = nl_pid_hash_alloc(size);
259 if (!table)
260 return 0;
261
262 memset(table, 0, size);
263 otable = hash->table;
264 hash->table = table;
265 hash->mask = mask;
266 hash->shift = shift;
267 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
268
269 for (i = 0; i <= omask; i++) {
270 struct sock *sk;
271 struct hlist_node *node, *tmp;
272
273 sk_for_each_safe(sk, node, tmp, &otable[i])
274 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
275 }
276
277 nl_pid_hash_free(otable, osize);
278 hash->rehash_time = jiffies + 10 * 60 * HZ;
279 return 1;
280 }
281
282 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
283 {
284 int avg = hash->entries >> hash->shift;
285
286 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
287 return 1;
288
289 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
290 nl_pid_hash_rehash(hash, 0);
291 return 1;
292 }
293
294 return 0;
295 }
296
297 static const struct proto_ops netlink_ops;
298
299 static void
300 netlink_update_listeners(struct sock *sk)
301 {
302 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
303 struct hlist_node *node;
304 unsigned long mask;
305 unsigned int i;
306
307 for (i = 0; i < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) {
308 mask = 0;
309 sk_for_each_bound(sk, node, &tbl->mc_list)
310 mask |= nlk_sk(sk)->groups[i];
311 tbl->listeners[i] = mask;
312 }
313 /* this function is only called with the netlink table "grabbed", which
314 * makes sure updates are visible before bind or setsockopt return. */
315 }
316
317 static int netlink_insert(struct sock *sk, u32 pid)
318 {
319 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
320 struct hlist_head *head;
321 int err = -EADDRINUSE;
322 struct sock *osk;
323 struct hlist_node *node;
324 int len;
325
326 netlink_table_grab();
327 head = nl_pid_hashfn(hash, pid);
328 len = 0;
329 sk_for_each(osk, node, head) {
330 if (nlk_sk(osk)->pid == pid)
331 break;
332 len++;
333 }
334 if (node)
335 goto err;
336
337 err = -EBUSY;
338 if (nlk_sk(sk)->pid)
339 goto err;
340
341 err = -ENOMEM;
342 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
343 goto err;
344
345 if (len && nl_pid_hash_dilute(hash, len))
346 head = nl_pid_hashfn(hash, pid);
347 hash->entries++;
348 nlk_sk(sk)->pid = pid;
349 sk_add_node(sk, head);
350 err = 0;
351
352 err:
353 netlink_table_ungrab();
354 return err;
355 }
356
357 static void netlink_remove(struct sock *sk)
358 {
359 netlink_table_grab();
360 if (sk_del_node_init(sk))
361 nl_table[sk->sk_protocol].hash.entries--;
362 if (nlk_sk(sk)->subscriptions)
363 __sk_del_bind_node(sk);
364 netlink_table_ungrab();
365 }
366
367 static struct proto netlink_proto = {
368 .name = "NETLINK",
369 .owner = THIS_MODULE,
370 .obj_size = sizeof(struct netlink_sock),
371 };
372
373 static int __netlink_create(struct socket *sock, int protocol)
374 {
375 struct sock *sk;
376 struct netlink_sock *nlk;
377
378 sock->ops = &netlink_ops;
379
380 sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
381 if (!sk)
382 return -ENOMEM;
383
384 sock_init_data(sock, sk);
385
386 nlk = nlk_sk(sk);
387 spin_lock_init(&nlk->cb_lock);
388 init_waitqueue_head(&nlk->wait);
389
390 sk->sk_destruct = netlink_sock_destruct;
391 sk->sk_protocol = protocol;
392 return 0;
393 }
394
395 static int netlink_create(struct socket *sock, int protocol)
396 {
397 struct module *module = NULL;
398 struct netlink_sock *nlk;
399 unsigned int groups;
400 int err = 0;
401
402 sock->state = SS_UNCONNECTED;
403
404 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
405 return -ESOCKTNOSUPPORT;
406
407 if (protocol<0 || protocol >= MAX_LINKS)
408 return -EPROTONOSUPPORT;
409
410 netlink_lock_table();
411 #ifdef CONFIG_KMOD
412 if (!nl_table[protocol].registered) {
413 netlink_unlock_table();
414 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
415 netlink_lock_table();
416 }
417 #endif
418 if (nl_table[protocol].registered &&
419 try_module_get(nl_table[protocol].module))
420 module = nl_table[protocol].module;
421 groups = nl_table[protocol].groups;
422 netlink_unlock_table();
423
424 if ((err = __netlink_create(sock, protocol)) < 0)
425 goto out_module;
426
427 nlk = nlk_sk(sock->sk);
428 nlk->module = module;
429 out:
430 return err;
431
432 out_module:
433 module_put(module);
434 goto out;
435 }
436
437 static int netlink_release(struct socket *sock)
438 {
439 struct sock *sk = sock->sk;
440 struct netlink_sock *nlk;
441
442 if (!sk)
443 return 0;
444
445 netlink_remove(sk);
446 sock_orphan(sk);
447 nlk = nlk_sk(sk);
448
449 spin_lock(&nlk->cb_lock);
450 if (nlk->cb) {
451 if (nlk->cb->done)
452 nlk->cb->done(nlk->cb);
453 netlink_destroy_callback(nlk->cb);
454 nlk->cb = NULL;
455 }
456 spin_unlock(&nlk->cb_lock);
457
458 /* OK. Socket is unlinked, and, therefore,
459 no new packets will arrive */
460
461 sock->sk = NULL;
462 wake_up_interruptible_all(&nlk->wait);
463
464 skb_queue_purge(&sk->sk_write_queue);
465
466 if (nlk->pid && !nlk->subscriptions) {
467 struct netlink_notify n = {
468 .protocol = sk->sk_protocol,
469 .pid = nlk->pid,
470 };
471 atomic_notifier_call_chain(&netlink_chain,
472 NETLINK_URELEASE, &n);
473 }
474
475 module_put(nlk->module);
476
477 netlink_table_grab();
478 if (nlk->flags & NETLINK_KERNEL_SOCKET) {
479 kfree(nl_table[sk->sk_protocol].listeners);
480 nl_table[sk->sk_protocol].module = NULL;
481 nl_table[sk->sk_protocol].registered = 0;
482 } else if (nlk->subscriptions)
483 netlink_update_listeners(sk);
484 netlink_table_ungrab();
485
486 kfree(nlk->groups);
487 nlk->groups = NULL;
488
489 sock_put(sk);
490 return 0;
491 }
492
493 static int netlink_autobind(struct socket *sock)
494 {
495 struct sock *sk = sock->sk;
496 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
497 struct hlist_head *head;
498 struct sock *osk;
499 struct hlist_node *node;
500 s32 pid = current->tgid;
501 int err;
502 static s32 rover = -4097;
503
504 retry:
505 cond_resched();
506 netlink_table_grab();
507 head = nl_pid_hashfn(hash, pid);
508 sk_for_each(osk, node, head) {
509 if (nlk_sk(osk)->pid == pid) {
510 /* Bind collision, search negative pid values. */
511 pid = rover--;
512 if (rover > -4097)
513 rover = -4097;
514 netlink_table_ungrab();
515 goto retry;
516 }
517 }
518 netlink_table_ungrab();
519
520 err = netlink_insert(sk, pid);
521 if (err == -EADDRINUSE)
522 goto retry;
523
524 /* If 2 threads race to autobind, that is fine. */
525 if (err == -EBUSY)
526 err = 0;
527
528 return err;
529 }
530
531 static inline int netlink_capable(struct socket *sock, unsigned int flag)
532 {
533 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
534 capable(CAP_NET_ADMIN);
535 }
536
537 static void
538 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
539 {
540 struct netlink_sock *nlk = nlk_sk(sk);
541
542 if (nlk->subscriptions && !subscriptions)
543 __sk_del_bind_node(sk);
544 else if (!nlk->subscriptions && subscriptions)
545 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
546 nlk->subscriptions = subscriptions;
547 }
548
549 static int netlink_alloc_groups(struct sock *sk)
550 {
551 struct netlink_sock *nlk = nlk_sk(sk);
552 unsigned int groups;
553 int err = 0;
554
555 netlink_lock_table();
556 groups = nl_table[sk->sk_protocol].groups;
557 if (!nl_table[sk->sk_protocol].registered)
558 err = -ENOENT;
559 netlink_unlock_table();
560
561 if (err)
562 return err;
563
564 nlk->groups = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
565 if (nlk->groups == NULL)
566 return -ENOMEM;
567 nlk->ngroups = groups;
568 return 0;
569 }
570
571 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
572 {
573 struct sock *sk = sock->sk;
574 struct netlink_sock *nlk = nlk_sk(sk);
575 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
576 int err;
577
578 if (nladdr->nl_family != AF_NETLINK)
579 return -EINVAL;
580
581 /* Only superuser is allowed to listen multicasts */
582 if (nladdr->nl_groups) {
583 if (!netlink_capable(sock, NL_NONROOT_RECV))
584 return -EPERM;
585 if (nlk->groups == NULL) {
586 err = netlink_alloc_groups(sk);
587 if (err)
588 return err;
589 }
590 }
591
592 if (nlk->pid) {
593 if (nladdr->nl_pid != nlk->pid)
594 return -EINVAL;
595 } else {
596 err = nladdr->nl_pid ?
597 netlink_insert(sk, nladdr->nl_pid) :
598 netlink_autobind(sock);
599 if (err)
600 return err;
601 }
602
603 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
604 return 0;
605
606 netlink_table_grab();
607 netlink_update_subscriptions(sk, nlk->subscriptions +
608 hweight32(nladdr->nl_groups) -
609 hweight32(nlk->groups[0]));
610 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
611 netlink_update_listeners(sk);
612 netlink_table_ungrab();
613
614 return 0;
615 }
616
617 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
618 int alen, int flags)
619 {
620 int err = 0;
621 struct sock *sk = sock->sk;
622 struct netlink_sock *nlk = nlk_sk(sk);
623 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr;
624
625 if (addr->sa_family == AF_UNSPEC) {
626 sk->sk_state = NETLINK_UNCONNECTED;
627 nlk->dst_pid = 0;
628 nlk->dst_group = 0;
629 return 0;
630 }
631 if (addr->sa_family != AF_NETLINK)
632 return -EINVAL;
633
634 /* Only superuser is allowed to send multicasts */
635 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
636 return -EPERM;
637
638 if (!nlk->pid)
639 err = netlink_autobind(sock);
640
641 if (err == 0) {
642 sk->sk_state = NETLINK_CONNECTED;
643 nlk->dst_pid = nladdr->nl_pid;
644 nlk->dst_group = ffs(nladdr->nl_groups);
645 }
646
647 return err;
648 }
649
650 static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer)
651 {
652 struct sock *sk = sock->sk;
653 struct netlink_sock *nlk = nlk_sk(sk);
654 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr;
655
656 nladdr->nl_family = AF_NETLINK;
657 nladdr->nl_pad = 0;
658 *addr_len = sizeof(*nladdr);
659
660 if (peer) {
661 nladdr->nl_pid = nlk->dst_pid;
662 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
663 } else {
664 nladdr->nl_pid = nlk->pid;
665 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
666 }
667 return 0;
668 }
669
670 static void netlink_overrun(struct sock *sk)
671 {
672 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
673 sk->sk_err = ENOBUFS;
674 sk->sk_error_report(sk);
675 }
676 }
677
678 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
679 {
680 int protocol = ssk->sk_protocol;
681 struct sock *sock;
682 struct netlink_sock *nlk;
683
684 sock = netlink_lookup(protocol, pid);
685 if (!sock)
686 return ERR_PTR(-ECONNREFUSED);
687
688 /* Don't bother queuing skb if kernel socket has no input function */
689 nlk = nlk_sk(sock);
690 if ((nlk->pid == 0 && !nlk->data_ready) ||
691 (sock->sk_state == NETLINK_CONNECTED &&
692 nlk->dst_pid != nlk_sk(ssk)->pid)) {
693 sock_put(sock);
694 return ERR_PTR(-ECONNREFUSED);
695 }
696 return sock;
697 }
698
699 struct sock *netlink_getsockbyfilp(struct file *filp)
700 {
701 struct inode *inode = filp->f_path.dentry->d_inode;
702 struct sock *sock;
703
704 if (!S_ISSOCK(inode->i_mode))
705 return ERR_PTR(-ENOTSOCK);
706
707 sock = SOCKET_I(inode)->sk;
708 if (sock->sk_family != AF_NETLINK)
709 return ERR_PTR(-EINVAL);
710
711 sock_hold(sock);
712 return sock;
713 }
714
715 /*
716 * Attach a skb to a netlink socket.
717 * The caller must hold a reference to the destination socket. On error, the
718 * reference is dropped. The skb is not send to the destination, just all
719 * all error checks are performed and memory in the queue is reserved.
720 * Return values:
721 * < 0: error. skb freed, reference to sock dropped.
722 * 0: continue
723 * 1: repeat lookup - reference dropped while waiting for socket memory.
724 */
725 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock,
726 long timeo, struct sock *ssk)
727 {
728 struct netlink_sock *nlk;
729
730 nlk = nlk_sk(sk);
731
732 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
733 test_bit(0, &nlk->state)) {
734 DECLARE_WAITQUEUE(wait, current);
735 if (!timeo) {
736 if (!ssk || nlk_sk(ssk)->pid == 0)
737 netlink_overrun(sk);
738 sock_put(sk);
739 kfree_skb(skb);
740 return -EAGAIN;
741 }
742
743 __set_current_state(TASK_INTERRUPTIBLE);
744 add_wait_queue(&nlk->wait, &wait);
745
746 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
747 test_bit(0, &nlk->state)) &&
748 !sock_flag(sk, SOCK_DEAD))
749 timeo = schedule_timeout(timeo);
750
751 __set_current_state(TASK_RUNNING);
752 remove_wait_queue(&nlk->wait, &wait);
753 sock_put(sk);
754
755 if (signal_pending(current)) {
756 kfree_skb(skb);
757 return sock_intr_errno(timeo);
758 }
759 return 1;
760 }
761 skb_set_owner_r(skb, sk);
762 return 0;
763 }
764
765 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol)
766 {
767 int len = skb->len;
768
769 skb_queue_tail(&sk->sk_receive_queue, skb);
770 sk->sk_data_ready(sk, len);
771 sock_put(sk);
772 return len;
773 }
774
775 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
776 {
777 kfree_skb(skb);
778 sock_put(sk);
779 }
780
781 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
782 gfp_t allocation)
783 {
784 int delta;
785
786 skb_orphan(skb);
787
788 delta = skb->end - skb->tail;
789 if (delta * 2 < skb->truesize)
790 return skb;
791
792 if (skb_shared(skb)) {
793 struct sk_buff *nskb = skb_clone(skb, allocation);
794 if (!nskb)
795 return skb;
796 kfree_skb(skb);
797 skb = nskb;
798 }
799
800 if (!pskb_expand_head(skb, 0, -delta, allocation))
801 skb->truesize -= delta;
802
803 return skb;
804 }
805
806 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock)
807 {
808 struct sock *sk;
809 int err;
810 long timeo;
811
812 skb = netlink_trim(skb, gfp_any());
813
814 timeo = sock_sndtimeo(ssk, nonblock);
815 retry:
816 sk = netlink_getsockbypid(ssk, pid);
817 if (IS_ERR(sk)) {
818 kfree_skb(skb);
819 return PTR_ERR(sk);
820 }
821 err = netlink_attachskb(sk, skb, nonblock, timeo, ssk);
822 if (err == 1)
823 goto retry;
824 if (err)
825 return err;
826
827 return netlink_sendskb(sk, skb, ssk->sk_protocol);
828 }
829
830 int netlink_has_listeners(struct sock *sk, unsigned int group)
831 {
832 int res = 0;
833
834 BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET));
835 if (group - 1 < nl_table[sk->sk_protocol].groups)
836 res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners);
837 return res;
838 }
839 EXPORT_SYMBOL_GPL(netlink_has_listeners);
840
841 static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
842 {
843 struct netlink_sock *nlk = nlk_sk(sk);
844
845 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
846 !test_bit(0, &nlk->state)) {
847 skb_set_owner_r(skb, sk);
848 skb_queue_tail(&sk->sk_receive_queue, skb);
849 sk->sk_data_ready(sk, skb->len);
850 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
851 }
852 return -1;
853 }
854
855 struct netlink_broadcast_data {
856 struct sock *exclude_sk;
857 u32 pid;
858 u32 group;
859 int failure;
860 int congested;
861 int delivered;
862 gfp_t allocation;
863 struct sk_buff *skb, *skb2;
864 };
865
866 static inline int do_one_broadcast(struct sock *sk,
867 struct netlink_broadcast_data *p)
868 {
869 struct netlink_sock *nlk = nlk_sk(sk);
870 int val;
871
872 if (p->exclude_sk == sk)
873 goto out;
874
875 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
876 !test_bit(p->group - 1, nlk->groups))
877 goto out;
878
879 if (p->failure) {
880 netlink_overrun(sk);
881 goto out;
882 }
883
884 sock_hold(sk);
885 if (p->skb2 == NULL) {
886 if (skb_shared(p->skb)) {
887 p->skb2 = skb_clone(p->skb, p->allocation);
888 } else {
889 p->skb2 = skb_get(p->skb);
890 /*
891 * skb ownership may have been set when
892 * delivered to a previous socket.
893 */
894 skb_orphan(p->skb2);
895 }
896 }
897 if (p->skb2 == NULL) {
898 netlink_overrun(sk);
899 /* Clone failed. Notify ALL listeners. */
900 p->failure = 1;
901 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
902 netlink_overrun(sk);
903 } else {
904 p->congested |= val;
905 p->delivered = 1;
906 p->skb2 = NULL;
907 }
908 sock_put(sk);
909
910 out:
911 return 0;
912 }
913
914 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
915 u32 group, gfp_t allocation)
916 {
917 struct netlink_broadcast_data info;
918 struct hlist_node *node;
919 struct sock *sk;
920
921 skb = netlink_trim(skb, allocation);
922
923 info.exclude_sk = ssk;
924 info.pid = pid;
925 info.group = group;
926 info.failure = 0;
927 info.congested = 0;
928 info.delivered = 0;
929 info.allocation = allocation;
930 info.skb = skb;
931 info.skb2 = NULL;
932
933 /* While we sleep in clone, do not allow to change socket list */
934
935 netlink_lock_table();
936
937 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
938 do_one_broadcast(sk, &info);
939
940 kfree_skb(skb);
941
942 netlink_unlock_table();
943
944 if (info.skb2)
945 kfree_skb(info.skb2);
946
947 if (info.delivered) {
948 if (info.congested && (allocation & __GFP_WAIT))
949 yield();
950 return 0;
951 }
952 if (info.failure)
953 return -ENOBUFS;
954 return -ESRCH;
955 }
956
957 struct netlink_set_err_data {
958 struct sock *exclude_sk;
959 u32 pid;
960 u32 group;
961 int code;
962 };
963
964 static inline int do_one_set_err(struct sock *sk,
965 struct netlink_set_err_data *p)
966 {
967 struct netlink_sock *nlk = nlk_sk(sk);
968
969 if (sk == p->exclude_sk)
970 goto out;
971
972 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
973 !test_bit(p->group - 1, nlk->groups))
974 goto out;
975
976 sk->sk_err = p->code;
977 sk->sk_error_report(sk);
978 out:
979 return 0;
980 }
981
982 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
983 {
984 struct netlink_set_err_data info;
985 struct hlist_node *node;
986 struct sock *sk;
987
988 info.exclude_sk = ssk;
989 info.pid = pid;
990 info.group = group;
991 info.code = code;
992
993 read_lock(&nl_table_lock);
994
995 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
996 do_one_set_err(sk, &info);
997
998 read_unlock(&nl_table_lock);
999 }
1000
1001 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1002 char __user *optval, int optlen)
1003 {
1004 struct sock *sk = sock->sk;
1005 struct netlink_sock *nlk = nlk_sk(sk);
1006 int val = 0, err;
1007
1008 if (level != SOL_NETLINK)
1009 return -ENOPROTOOPT;
1010
1011 if (optlen >= sizeof(int) &&
1012 get_user(val, (int __user *)optval))
1013 return -EFAULT;
1014
1015 switch (optname) {
1016 case NETLINK_PKTINFO:
1017 if (val)
1018 nlk->flags |= NETLINK_RECV_PKTINFO;
1019 else
1020 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1021 err = 0;
1022 break;
1023 case NETLINK_ADD_MEMBERSHIP:
1024 case NETLINK_DROP_MEMBERSHIP: {
1025 unsigned int subscriptions;
1026 int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0;
1027
1028 if (!netlink_capable(sock, NL_NONROOT_RECV))
1029 return -EPERM;
1030 if (nlk->groups == NULL) {
1031 err = netlink_alloc_groups(sk);
1032 if (err)
1033 return err;
1034 }
1035 if (!val || val - 1 >= nlk->ngroups)
1036 return -EINVAL;
1037 netlink_table_grab();
1038 old = test_bit(val - 1, nlk->groups);
1039 subscriptions = nlk->subscriptions - old + new;
1040 if (new)
1041 __set_bit(val - 1, nlk->groups);
1042 else
1043 __clear_bit(val - 1, nlk->groups);
1044 netlink_update_subscriptions(sk, subscriptions);
1045 netlink_update_listeners(sk);
1046 netlink_table_ungrab();
1047 err = 0;
1048 break;
1049 }
1050 default:
1051 err = -ENOPROTOOPT;
1052 }
1053 return err;
1054 }
1055
1056 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1057 char __user *optval, int __user *optlen)
1058 {
1059 struct sock *sk = sock->sk;
1060 struct netlink_sock *nlk = nlk_sk(sk);
1061 int len, val, err;
1062
1063 if (level != SOL_NETLINK)
1064 return -ENOPROTOOPT;
1065
1066 if (get_user(len, optlen))
1067 return -EFAULT;
1068 if (len < 0)
1069 return -EINVAL;
1070
1071 switch (optname) {
1072 case NETLINK_PKTINFO:
1073 if (len < sizeof(int))
1074 return -EINVAL;
1075 len = sizeof(int);
1076 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1077 if (put_user(len, optlen) ||
1078 put_user(val, optval))
1079 return -EFAULT;
1080 err = 0;
1081 break;
1082 default:
1083 err = -ENOPROTOOPT;
1084 }
1085 return err;
1086 }
1087
1088 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1089 {
1090 struct nl_pktinfo info;
1091
1092 info.group = NETLINK_CB(skb).dst_group;
1093 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1094 }
1095
1096 static inline void netlink_rcv_wake(struct sock *sk)
1097 {
1098 struct netlink_sock *nlk = nlk_sk(sk);
1099
1100 if (skb_queue_empty(&sk->sk_receive_queue))
1101 clear_bit(0, &nlk->state);
1102 if (!test_bit(0, &nlk->state))
1103 wake_up_interruptible(&nlk->wait);
1104 }
1105
1106 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1107 struct msghdr *msg, size_t len)
1108 {
1109 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1110 struct sock *sk = sock->sk;
1111 struct netlink_sock *nlk = nlk_sk(sk);
1112 struct sockaddr_nl *addr=msg->msg_name;
1113 u32 dst_pid;
1114 u32 dst_group;
1115 struct sk_buff *skb;
1116 int err;
1117 struct scm_cookie scm;
1118
1119 if (msg->msg_flags&MSG_OOB)
1120 return -EOPNOTSUPP;
1121
1122 if (NULL == siocb->scm)
1123 siocb->scm = &scm;
1124 err = scm_send(sock, msg, siocb->scm);
1125 if (err < 0)
1126 return err;
1127
1128 if (msg->msg_namelen) {
1129 if (addr->nl_family != AF_NETLINK)
1130 return -EINVAL;
1131 dst_pid = addr->nl_pid;
1132 dst_group = ffs(addr->nl_groups);
1133 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1134 return -EPERM;
1135 } else {
1136 dst_pid = nlk->dst_pid;
1137 dst_group = nlk->dst_group;
1138 }
1139
1140 if (!nlk->pid) {
1141 err = netlink_autobind(sock);
1142 if (err)
1143 goto out;
1144 }
1145
1146 err = -EMSGSIZE;
1147 if (len > sk->sk_sndbuf - 32)
1148 goto out;
1149 err = -ENOBUFS;
1150 skb = alloc_skb(len, GFP_KERNEL);
1151 if (skb==NULL)
1152 goto out;
1153
1154 NETLINK_CB(skb).pid = nlk->pid;
1155 NETLINK_CB(skb).dst_group = dst_group;
1156 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
1157 selinux_get_task_sid(current, &(NETLINK_CB(skb).sid));
1158 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1159
1160 /* What can I do? Netlink is asynchronous, so that
1161 we will have to save current capabilities to
1162 check them, when this message will be delivered
1163 to corresponding kernel module. --ANK (980802)
1164 */
1165
1166 err = -EFAULT;
1167 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) {
1168 kfree_skb(skb);
1169 goto out;
1170 }
1171
1172 err = security_netlink_send(sk, skb);
1173 if (err) {
1174 kfree_skb(skb);
1175 goto out;
1176 }
1177
1178 if (dst_group) {
1179 atomic_inc(&skb->users);
1180 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1181 }
1182 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1183
1184 out:
1185 return err;
1186 }
1187
1188 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1189 struct msghdr *msg, size_t len,
1190 int flags)
1191 {
1192 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1193 struct scm_cookie scm;
1194 struct sock *sk = sock->sk;
1195 struct netlink_sock *nlk = nlk_sk(sk);
1196 int noblock = flags&MSG_DONTWAIT;
1197 size_t copied;
1198 struct sk_buff *skb;
1199 int err;
1200
1201 if (flags&MSG_OOB)
1202 return -EOPNOTSUPP;
1203
1204 copied = 0;
1205
1206 skb = skb_recv_datagram(sk,flags,noblock,&err);
1207 if (skb==NULL)
1208 goto out;
1209
1210 msg->msg_namelen = 0;
1211
1212 copied = skb->len;
1213 if (len < copied) {
1214 msg->msg_flags |= MSG_TRUNC;
1215 copied = len;
1216 }
1217
1218 skb_reset_transport_header(skb);
1219 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1220
1221 if (msg->msg_name) {
1222 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name;
1223 addr->nl_family = AF_NETLINK;
1224 addr->nl_pad = 0;
1225 addr->nl_pid = NETLINK_CB(skb).pid;
1226 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1227 msg->msg_namelen = sizeof(*addr);
1228 }
1229
1230 if (nlk->flags & NETLINK_RECV_PKTINFO)
1231 netlink_cmsg_recv_pktinfo(msg, skb);
1232
1233 if (NULL == siocb->scm) {
1234 memset(&scm, 0, sizeof(scm));
1235 siocb->scm = &scm;
1236 }
1237 siocb->scm->creds = *NETLINK_CREDS(skb);
1238 skb_free_datagram(sk, skb);
1239
1240 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1241 netlink_dump(sk);
1242
1243 scm_recv(sock, msg, siocb->scm, flags);
1244
1245 if (flags & MSG_TRUNC)
1246 copied = skb->len;
1247
1248 out:
1249 netlink_rcv_wake(sk);
1250 return err ? : copied;
1251 }
1252
1253 static void netlink_data_ready(struct sock *sk, int len)
1254 {
1255 struct netlink_sock *nlk = nlk_sk(sk);
1256
1257 if (nlk->data_ready)
1258 nlk->data_ready(sk, len);
1259 netlink_rcv_wake(sk);
1260 }
1261
1262 /*
1263 * We export these functions to other modules. They provide a
1264 * complete set of kernel non-blocking support for message
1265 * queueing.
1266 */
1267
1268 struct sock *
1269 netlink_kernel_create(int unit, unsigned int groups,
1270 void (*input)(struct sock *sk, int len),
1271 struct module *module)
1272 {
1273 struct socket *sock;
1274 struct sock *sk;
1275 struct netlink_sock *nlk;
1276 unsigned long *listeners = NULL;
1277
1278 BUG_ON(!nl_table);
1279
1280 if (unit<0 || unit>=MAX_LINKS)
1281 return NULL;
1282
1283 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1284 return NULL;
1285
1286 if (__netlink_create(sock, unit) < 0)
1287 goto out_sock_release;
1288
1289 if (groups < 32)
1290 groups = 32;
1291
1292 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
1293 if (!listeners)
1294 goto out_sock_release;
1295
1296 sk = sock->sk;
1297 sk->sk_data_ready = netlink_data_ready;
1298 if (input)
1299 nlk_sk(sk)->data_ready = input;
1300
1301 if (netlink_insert(sk, 0))
1302 goto out_sock_release;
1303
1304 nlk = nlk_sk(sk);
1305 nlk->flags |= NETLINK_KERNEL_SOCKET;
1306
1307 netlink_table_grab();
1308 nl_table[unit].groups = groups;
1309 nl_table[unit].listeners = listeners;
1310 nl_table[unit].module = module;
1311 nl_table[unit].registered = 1;
1312 netlink_table_ungrab();
1313
1314 return sk;
1315
1316 out_sock_release:
1317 kfree(listeners);
1318 sock_release(sock);
1319 return NULL;
1320 }
1321
1322 void netlink_set_nonroot(int protocol, unsigned int flags)
1323 {
1324 if ((unsigned int)protocol < MAX_LINKS)
1325 nl_table[protocol].nl_nonroot = flags;
1326 }
1327
1328 static void netlink_destroy_callback(struct netlink_callback *cb)
1329 {
1330 if (cb->skb)
1331 kfree_skb(cb->skb);
1332 kfree(cb);
1333 }
1334
1335 /*
1336 * It looks a bit ugly.
1337 * It would be better to create kernel thread.
1338 */
1339
1340 static int netlink_dump(struct sock *sk)
1341 {
1342 struct netlink_sock *nlk = nlk_sk(sk);
1343 struct netlink_callback *cb;
1344 struct sk_buff *skb;
1345 struct nlmsghdr *nlh;
1346 int len, err = -ENOBUFS;
1347
1348 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1349 if (!skb)
1350 goto errout;
1351
1352 spin_lock(&nlk->cb_lock);
1353
1354 cb = nlk->cb;
1355 if (cb == NULL) {
1356 err = -EINVAL;
1357 goto errout_skb;
1358 }
1359
1360 len = cb->dump(skb, cb);
1361
1362 if (len > 0) {
1363 spin_unlock(&nlk->cb_lock);
1364 skb_queue_tail(&sk->sk_receive_queue, skb);
1365 sk->sk_data_ready(sk, len);
1366 return 0;
1367 }
1368
1369 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1370 if (!nlh)
1371 goto errout_skb;
1372
1373 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1374
1375 skb_queue_tail(&sk->sk_receive_queue, skb);
1376 sk->sk_data_ready(sk, skb->len);
1377
1378 if (cb->done)
1379 cb->done(cb);
1380 nlk->cb = NULL;
1381 spin_unlock(&nlk->cb_lock);
1382
1383 netlink_destroy_callback(cb);
1384 return 0;
1385
1386 errout_skb:
1387 spin_unlock(&nlk->cb_lock);
1388 kfree_skb(skb);
1389 errout:
1390 return err;
1391 }
1392
1393 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1394 struct nlmsghdr *nlh,
1395 int (*dump)(struct sk_buff *skb, struct netlink_callback*),
1396 int (*done)(struct netlink_callback*))
1397 {
1398 struct netlink_callback *cb;
1399 struct sock *sk;
1400 struct netlink_sock *nlk;
1401
1402 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1403 if (cb == NULL)
1404 return -ENOBUFS;
1405
1406 cb->dump = dump;
1407 cb->done = done;
1408 cb->nlh = nlh;
1409 atomic_inc(&skb->users);
1410 cb->skb = skb;
1411
1412 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid);
1413 if (sk == NULL) {
1414 netlink_destroy_callback(cb);
1415 return -ECONNREFUSED;
1416 }
1417 nlk = nlk_sk(sk);
1418 /* A dump or destruction is in progress... */
1419 spin_lock(&nlk->cb_lock);
1420 if (nlk->cb || sock_flag(sk, SOCK_DEAD)) {
1421 spin_unlock(&nlk->cb_lock);
1422 netlink_destroy_callback(cb);
1423 sock_put(sk);
1424 return -EBUSY;
1425 }
1426 nlk->cb = cb;
1427 spin_unlock(&nlk->cb_lock);
1428
1429 netlink_dump(sk);
1430 sock_put(sk);
1431 return 0;
1432 }
1433
1434 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1435 {
1436 struct sk_buff *skb;
1437 struct nlmsghdr *rep;
1438 struct nlmsgerr *errmsg;
1439 size_t payload = sizeof(*errmsg);
1440
1441 /* error messages get the original request appened */
1442 if (err)
1443 payload += nlmsg_len(nlh);
1444
1445 skb = nlmsg_new(payload, GFP_KERNEL);
1446 if (!skb) {
1447 struct sock *sk;
1448
1449 sk = netlink_lookup(in_skb->sk->sk_protocol,
1450 NETLINK_CB(in_skb).pid);
1451 if (sk) {
1452 sk->sk_err = ENOBUFS;
1453 sk->sk_error_report(sk);
1454 sock_put(sk);
1455 }
1456 return;
1457 }
1458
1459 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1460 NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
1461 errmsg = nlmsg_data(rep);
1462 errmsg->error = err;
1463 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1464 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1465 }
1466
1467 static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1468 struct nlmsghdr *, int *))
1469 {
1470 struct nlmsghdr *nlh;
1471 int err;
1472
1473 while (skb->len >= nlmsg_total_size(0)) {
1474 nlh = (struct nlmsghdr *) skb->data;
1475
1476 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1477 return 0;
1478
1479 if (cb(skb, nlh, &err) < 0) {
1480 /* Not an error, but we have to interrupt processing
1481 * here. Note: that in this case we do not pull
1482 * message from skb, it will be processed later.
1483 */
1484 if (err == 0)
1485 return -1;
1486 netlink_ack(skb, nlh, err);
1487 } else if (nlh->nlmsg_flags & NLM_F_ACK)
1488 netlink_ack(skb, nlh, 0);
1489
1490 netlink_queue_skip(nlh, skb);
1491 }
1492
1493 return 0;
1494 }
1495
1496 /**
1497 * nelink_run_queue - Process netlink receive queue.
1498 * @sk: Netlink socket containing the queue
1499 * @qlen: Place to store queue length upon entry
1500 * @cb: Callback function invoked for each netlink message found
1501 *
1502 * Processes as much as there was in the queue upon entry and invokes
1503 * a callback function for each netlink message found. The callback
1504 * function may refuse a message by returning a negative error code
1505 * but setting the error pointer to 0 in which case this function
1506 * returns with a qlen != 0.
1507 *
1508 * qlen must be initialized to 0 before the initial entry, afterwards
1509 * the function may be called repeatedly until qlen reaches 0.
1510 */
1511 void netlink_run_queue(struct sock *sk, unsigned int *qlen,
1512 int (*cb)(struct sk_buff *, struct nlmsghdr *, int *))
1513 {
1514 struct sk_buff *skb;
1515
1516 if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue))
1517 *qlen = skb_queue_len(&sk->sk_receive_queue);
1518
1519 for (; *qlen; (*qlen)--) {
1520 skb = skb_dequeue(&sk->sk_receive_queue);
1521 if (netlink_rcv_skb(skb, cb)) {
1522 if (skb->len)
1523 skb_queue_head(&sk->sk_receive_queue, skb);
1524 else {
1525 kfree_skb(skb);
1526 (*qlen)--;
1527 }
1528 break;
1529 }
1530
1531 kfree_skb(skb);
1532 }
1533 }
1534
1535 /**
1536 * netlink_queue_skip - Skip netlink message while processing queue.
1537 * @nlh: Netlink message to be skipped
1538 * @skb: Socket buffer containing the netlink messages.
1539 *
1540 * Pulls the given netlink message off the socket buffer so the next
1541 * call to netlink_queue_run() will not reconsider the message.
1542 */
1543 void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb)
1544 {
1545 int msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1546
1547 if (msglen > skb->len)
1548 msglen = skb->len;
1549
1550 skb_pull(skb, msglen);
1551 }
1552
1553 /**
1554 * nlmsg_notify - send a notification netlink message
1555 * @sk: netlink socket to use
1556 * @skb: notification message
1557 * @pid: destination netlink pid for reports or 0
1558 * @group: destination multicast group or 0
1559 * @report: 1 to report back, 0 to disable
1560 * @flags: allocation flags
1561 */
1562 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1563 unsigned int group, int report, gfp_t flags)
1564 {
1565 int err = 0;
1566
1567 if (group) {
1568 int exclude_pid = 0;
1569
1570 if (report) {
1571 atomic_inc(&skb->users);
1572 exclude_pid = pid;
1573 }
1574
1575 /* errors reported via destination sk->sk_err */
1576 nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1577 }
1578
1579 if (report)
1580 err = nlmsg_unicast(sk, skb, pid);
1581
1582 return err;
1583 }
1584
1585 #ifdef CONFIG_PROC_FS
1586 struct nl_seq_iter {
1587 int link;
1588 int hash_idx;
1589 };
1590
1591 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1592 {
1593 struct nl_seq_iter *iter = seq->private;
1594 int i, j;
1595 struct sock *s;
1596 struct hlist_node *node;
1597 loff_t off = 0;
1598
1599 for (i=0; i<MAX_LINKS; i++) {
1600 struct nl_pid_hash *hash = &nl_table[i].hash;
1601
1602 for (j = 0; j <= hash->mask; j++) {
1603 sk_for_each(s, node, &hash->table[j]) {
1604 if (off == pos) {
1605 iter->link = i;
1606 iter->hash_idx = j;
1607 return s;
1608 }
1609 ++off;
1610 }
1611 }
1612 }
1613 return NULL;
1614 }
1615
1616 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1617 {
1618 read_lock(&nl_table_lock);
1619 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1620 }
1621
1622 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1623 {
1624 struct sock *s;
1625 struct nl_seq_iter *iter;
1626 int i, j;
1627
1628 ++*pos;
1629
1630 if (v == SEQ_START_TOKEN)
1631 return netlink_seq_socket_idx(seq, 0);
1632
1633 s = sk_next(v);
1634 if (s)
1635 return s;
1636
1637 iter = seq->private;
1638 i = iter->link;
1639 j = iter->hash_idx + 1;
1640
1641 do {
1642 struct nl_pid_hash *hash = &nl_table[i].hash;
1643
1644 for (; j <= hash->mask; j++) {
1645 s = sk_head(&hash->table[j]);
1646 if (s) {
1647 iter->link = i;
1648 iter->hash_idx = j;
1649 return s;
1650 }
1651 }
1652
1653 j = 0;
1654 } while (++i < MAX_LINKS);
1655
1656 return NULL;
1657 }
1658
1659 static void netlink_seq_stop(struct seq_file *seq, void *v)
1660 {
1661 read_unlock(&nl_table_lock);
1662 }
1663
1664
1665 static int netlink_seq_show(struct seq_file *seq, void *v)
1666 {
1667 if (v == SEQ_START_TOKEN)
1668 seq_puts(seq,
1669 "sk Eth Pid Groups "
1670 "Rmem Wmem Dump Locks\n");
1671 else {
1672 struct sock *s = v;
1673 struct netlink_sock *nlk = nlk_sk(s);
1674
1675 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
1676 s,
1677 s->sk_protocol,
1678 nlk->pid,
1679 nlk->groups ? (u32)nlk->groups[0] : 0,
1680 atomic_read(&s->sk_rmem_alloc),
1681 atomic_read(&s->sk_wmem_alloc),
1682 nlk->cb,
1683 atomic_read(&s->sk_refcnt)
1684 );
1685
1686 }
1687 return 0;
1688 }
1689
1690 static struct seq_operations netlink_seq_ops = {
1691 .start = netlink_seq_start,
1692 .next = netlink_seq_next,
1693 .stop = netlink_seq_stop,
1694 .show = netlink_seq_show,
1695 };
1696
1697
1698 static int netlink_seq_open(struct inode *inode, struct file *file)
1699 {
1700 struct seq_file *seq;
1701 struct nl_seq_iter *iter;
1702 int err;
1703
1704 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1705 if (!iter)
1706 return -ENOMEM;
1707
1708 err = seq_open(file, &netlink_seq_ops);
1709 if (err) {
1710 kfree(iter);
1711 return err;
1712 }
1713
1714 seq = file->private_data;
1715 seq->private = iter;
1716 return 0;
1717 }
1718
1719 static const struct file_operations netlink_seq_fops = {
1720 .owner = THIS_MODULE,
1721 .open = netlink_seq_open,
1722 .read = seq_read,
1723 .llseek = seq_lseek,
1724 .release = seq_release_private,
1725 };
1726
1727 #endif
1728
1729 int netlink_register_notifier(struct notifier_block *nb)
1730 {
1731 return atomic_notifier_chain_register(&netlink_chain, nb);
1732 }
1733
1734 int netlink_unregister_notifier(struct notifier_block *nb)
1735 {
1736 return atomic_notifier_chain_unregister(&netlink_chain, nb);
1737 }
1738
1739 static const struct proto_ops netlink_ops = {
1740 .family = PF_NETLINK,
1741 .owner = THIS_MODULE,
1742 .release = netlink_release,
1743 .bind = netlink_bind,
1744 .connect = netlink_connect,
1745 .socketpair = sock_no_socketpair,
1746 .accept = sock_no_accept,
1747 .getname = netlink_getname,
1748 .poll = datagram_poll,
1749 .ioctl = sock_no_ioctl,
1750 .listen = sock_no_listen,
1751 .shutdown = sock_no_shutdown,
1752 .setsockopt = netlink_setsockopt,
1753 .getsockopt = netlink_getsockopt,
1754 .sendmsg = netlink_sendmsg,
1755 .recvmsg = netlink_recvmsg,
1756 .mmap = sock_no_mmap,
1757 .sendpage = sock_no_sendpage,
1758 };
1759
1760 static struct net_proto_family netlink_family_ops = {
1761 .family = PF_NETLINK,
1762 .create = netlink_create,
1763 .owner = THIS_MODULE, /* for consistency 8) */
1764 };
1765
1766 static int __init netlink_proto_init(void)
1767 {
1768 struct sk_buff *dummy_skb;
1769 int i;
1770 unsigned long max;
1771 unsigned int order;
1772 int err = proto_register(&netlink_proto, 0);
1773
1774 if (err != 0)
1775 goto out;
1776
1777 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
1778
1779 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
1780 if (!nl_table)
1781 goto panic;
1782
1783 if (num_physpages >= (128 * 1024))
1784 max = num_physpages >> (21 - PAGE_SHIFT);
1785 else
1786 max = num_physpages >> (23 - PAGE_SHIFT);
1787
1788 order = get_bitmask_order(max) - 1 + PAGE_SHIFT;
1789 max = (1UL << order) / sizeof(struct hlist_head);
1790 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1;
1791
1792 for (i = 0; i < MAX_LINKS; i++) {
1793 struct nl_pid_hash *hash = &nl_table[i].hash;
1794
1795 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table));
1796 if (!hash->table) {
1797 while (i-- > 0)
1798 nl_pid_hash_free(nl_table[i].hash.table,
1799 1 * sizeof(*hash->table));
1800 kfree(nl_table);
1801 goto panic;
1802 }
1803 memset(hash->table, 0, 1 * sizeof(*hash->table));
1804 hash->max_shift = order;
1805 hash->shift = 0;
1806 hash->mask = 0;
1807 hash->rehash_time = jiffies;
1808 }
1809
1810 sock_register(&netlink_family_ops);
1811 #ifdef CONFIG_PROC_FS
1812 proc_net_fops_create("netlink", 0, &netlink_seq_fops);
1813 #endif
1814 /* The netlink device handler may be needed early. */
1815 rtnetlink_init();
1816 out:
1817 return err;
1818 panic:
1819 panic("netlink_init: Cannot allocate nl_table\n");
1820 }
1821
1822 core_initcall(netlink_proto_init);
1823
1824 EXPORT_SYMBOL(netlink_ack);
1825 EXPORT_SYMBOL(netlink_run_queue);
1826 EXPORT_SYMBOL(netlink_queue_skip);
1827 EXPORT_SYMBOL(netlink_broadcast);
1828 EXPORT_SYMBOL(netlink_dump_start);
1829 EXPORT_SYMBOL(netlink_kernel_create);
1830 EXPORT_SYMBOL(netlink_register_notifier);
1831 EXPORT_SYMBOL(netlink_set_nonroot);
1832 EXPORT_SYMBOL(netlink_unicast);
1833 EXPORT_SYMBOL(netlink_unregister_notifier);
1834 EXPORT_SYMBOL(nlmsg_notify);
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