projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
[NET]: Make all initialized struct seq_operations const.
[deliverable/linux.git] / net / netlink / af_netlink.c
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/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/selinux.h>
58 #include <linux/mutex.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 struct mutex *cb_mutex;
80 struct mutex cb_def_mutex;
81 void (*data_ready)(struct sock *sk, int bytes);
82 struct module *module;
83 };
84
85 #define NETLINK_KERNEL_SOCKET 0x1
86 #define NETLINK_RECV_PKTINFO 0x2
87
88 static inline struct netlink_sock *nlk_sk(struct sock *sk)
89 {
90 return (struct netlink_sock *)sk;
91 }
92
93 struct nl_pid_hash {
94 struct hlist_head *table;
95 unsigned long rehash_time;
96
97 unsigned int mask;
98 unsigned int shift;
99
100 unsigned int entries;
101 unsigned int max_shift;
102
103 u32 rnd;
104 };
105
106 struct netlink_table {
107 struct nl_pid_hash hash;
108 struct hlist_head mc_list;
109 unsigned long *listeners;
110 unsigned int nl_nonroot;
111 unsigned int groups;
112 struct mutex *cb_mutex;
113 struct module *module;
114 int registered;
115 };
116
117 static struct netlink_table *nl_table;
118
119 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
120
121 static int netlink_dump(struct sock *sk);
122 static void netlink_destroy_callback(struct netlink_callback *cb);
123 static void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb);
124
125 static DEFINE_RWLOCK(nl_table_lock);
126 static atomic_t nl_table_users = ATOMIC_INIT(0);
127
128 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
129
130 static u32 netlink_group_mask(u32 group)
131 {
132 return group ? 1 << (group - 1) : 0;
133 }
134
135 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
136 {
137 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
138 }
139
140 static void netlink_sock_destruct(struct sock *sk)
141 {
142 struct netlink_sock *nlk = nlk_sk(sk);
143
144 if (nlk->cb) {
145 if (nlk->cb->done)
146 nlk->cb->done(nlk->cb);
147 netlink_destroy_callback(nlk->cb);
148 }
149
150 skb_queue_purge(&sk->sk_receive_queue);
151
152 if (!sock_flag(sk, SOCK_DEAD)) {
153 printk("Freeing alive netlink socket %p\n", sk);
154 return;
155 }
156 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
157 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
158 BUG_TRAP(!nlk_sk(sk)->groups);
159 }
160
161 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
162 * Look, when several writers sleep and reader wakes them up, all but one
163 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
164 * this, _but_ remember, it adds useless work on UP machines.
165 */
166
167 static void netlink_table_grab(void)
168 {
169 write_lock_irq(&nl_table_lock);
170
171 if (atomic_read(&nl_table_users)) {
172 DECLARE_WAITQUEUE(wait, current);
173
174 add_wait_queue_exclusive(&nl_table_wait, &wait);
175 for(;;) {
176 set_current_state(TASK_UNINTERRUPTIBLE);
177 if (atomic_read(&nl_table_users) == 0)
178 break;
179 write_unlock_irq(&nl_table_lock);
180 schedule();
181 write_lock_irq(&nl_table_lock);
182 }
183
184 __set_current_state(TASK_RUNNING);
185 remove_wait_queue(&nl_table_wait, &wait);
186 }
187 }
188
189 static __inline__ void netlink_table_ungrab(void)
190 {
191 write_unlock_irq(&nl_table_lock);
192 wake_up(&nl_table_wait);
193 }
194
195 static __inline__ void
196 netlink_lock_table(void)
197 {
198 /* read_lock() synchronizes us to netlink_table_grab */
199
200 read_lock(&nl_table_lock);
201 atomic_inc(&nl_table_users);
202 read_unlock(&nl_table_lock);
203 }
204
205 static __inline__ void
206 netlink_unlock_table(void)
207 {
208 if (atomic_dec_and_test(&nl_table_users))
209 wake_up(&nl_table_wait);
210 }
211
212 static __inline__ struct sock *netlink_lookup(int protocol, u32 pid)
213 {
214 struct nl_pid_hash *hash = &nl_table[protocol].hash;
215 struct hlist_head *head;
216 struct sock *sk;
217 struct hlist_node *node;
218
219 read_lock(&nl_table_lock);
220 head = nl_pid_hashfn(hash, pid);
221 sk_for_each(sk, node, head) {
222 if (nlk_sk(sk)->pid == pid) {
223 sock_hold(sk);
224 goto found;
225 }
226 }
227 sk = NULL;
228 found:
229 read_unlock(&nl_table_lock);
230 return sk;
231 }
232
233 static inline struct hlist_head *nl_pid_hash_alloc(size_t size)
234 {
235 if (size <= PAGE_SIZE)
236 return kmalloc(size, GFP_ATOMIC);
237 else
238 return (struct hlist_head *)
239 __get_free_pages(GFP_ATOMIC, get_order(size));
240 }
241
242 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
243 {
244 if (size <= PAGE_SIZE)
245 kfree(table);
246 else
247 free_pages((unsigned long)table, get_order(size));
248 }
249
250 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
251 {
252 unsigned int omask, mask, shift;
253 size_t osize, size;
254 struct hlist_head *otable, *table;
255 int i;
256
257 omask = mask = hash->mask;
258 osize = size = (mask + 1) * sizeof(*table);
259 shift = hash->shift;
260
261 if (grow) {
262 if (++shift > hash->max_shift)
263 return 0;
264 mask = mask * 2 + 1;
265 size *= 2;
266 }
267
268 table = nl_pid_hash_alloc(size);
269 if (!table)
270 return 0;
271
272 memset(table, 0, size);
273 otable = hash->table;
274 hash->table = table;
275 hash->mask = mask;
276 hash->shift = shift;
277 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
278
279 for (i = 0; i <= omask; i++) {
280 struct sock *sk;
281 struct hlist_node *node, *tmp;
282
283 sk_for_each_safe(sk, node, tmp, &otable[i])
284 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
285 }
286
287 nl_pid_hash_free(otable, osize);
288 hash->rehash_time = jiffies + 10 * 60 * HZ;
289 return 1;
290 }
291
292 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
293 {
294 int avg = hash->entries >> hash->shift;
295
296 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
297 return 1;
298
299 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
300 nl_pid_hash_rehash(hash, 0);
301 return 1;
302 }
303
304 return 0;
305 }
306
307 static const struct proto_ops netlink_ops;
308
309 static void
310 netlink_update_listeners(struct sock *sk)
311 {
312 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
313 struct hlist_node *node;
314 unsigned long mask;
315 unsigned int i;
316
317 for (i = 0; i < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) {
318 mask = 0;
319 sk_for_each_bound(sk, node, &tbl->mc_list)
320 mask |= nlk_sk(sk)->groups[i];
321 tbl->listeners[i] = mask;
322 }
323 /* this function is only called with the netlink table "grabbed", which
324 * makes sure updates are visible before bind or setsockopt return. */
325 }
326
327 static int netlink_insert(struct sock *sk, u32 pid)
328 {
329 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
330 struct hlist_head *head;
331 int err = -EADDRINUSE;
332 struct sock *osk;
333 struct hlist_node *node;
334 int len;
335
336 netlink_table_grab();
337 head = nl_pid_hashfn(hash, pid);
338 len = 0;
339 sk_for_each(osk, node, head) {
340 if (nlk_sk(osk)->pid == pid)
341 break;
342 len++;
343 }
344 if (node)
345 goto err;
346
347 err = -EBUSY;
348 if (nlk_sk(sk)->pid)
349 goto err;
350
351 err = -ENOMEM;
352 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
353 goto err;
354
355 if (len && nl_pid_hash_dilute(hash, len))
356 head = nl_pid_hashfn(hash, pid);
357 hash->entries++;
358 nlk_sk(sk)->pid = pid;
359 sk_add_node(sk, head);
360 err = 0;
361
362 err:
363 netlink_table_ungrab();
364 return err;
365 }
366
367 static void netlink_remove(struct sock *sk)
368 {
369 netlink_table_grab();
370 if (sk_del_node_init(sk))
371 nl_table[sk->sk_protocol].hash.entries--;
372 if (nlk_sk(sk)->subscriptions)
373 __sk_del_bind_node(sk);
374 netlink_table_ungrab();
375 }
376
377 static struct proto netlink_proto = {
378 .name = "NETLINK",
379 .owner = THIS_MODULE,
380 .obj_size = sizeof(struct netlink_sock),
381 };
382
383 static int __netlink_create(struct socket *sock, struct mutex *cb_mutex,
384 int protocol)
385 {
386 struct sock *sk;
387 struct netlink_sock *nlk;
388
389 sock->ops = &netlink_ops;
390
391 sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
392 if (!sk)
393 return -ENOMEM;
394
395 sock_init_data(sock, sk);
396
397 nlk = nlk_sk(sk);
398 if (cb_mutex)
399 nlk->cb_mutex = cb_mutex;
400 else {
401 nlk->cb_mutex = &nlk->cb_def_mutex;
402 mutex_init(nlk->cb_mutex);
403 }
404 init_waitqueue_head(&nlk->wait);
405
406 sk->sk_destruct = netlink_sock_destruct;
407 sk->sk_protocol = protocol;
408 return 0;
409 }
410
411 static int netlink_create(struct socket *sock, int protocol)
412 {
413 struct module *module = NULL;
414 struct mutex *cb_mutex;
415 struct netlink_sock *nlk;
416 int err = 0;
417
418 sock->state = SS_UNCONNECTED;
419
420 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
421 return -ESOCKTNOSUPPORT;
422
423 if (protocol<0 || protocol >= MAX_LINKS)
424 return -EPROTONOSUPPORT;
425
426 netlink_lock_table();
427 #ifdef CONFIG_KMOD
428 if (!nl_table[protocol].registered) {
429 netlink_unlock_table();
430 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
431 netlink_lock_table();
432 }
433 #endif
434 if (nl_table[protocol].registered &&
435 try_module_get(nl_table[protocol].module))
436 module = nl_table[protocol].module;
437 cb_mutex = nl_table[protocol].cb_mutex;
438 netlink_unlock_table();
439
440 if ((err = __netlink_create(sock, cb_mutex, protocol)) < 0)
441 goto out_module;
442
443 nlk = nlk_sk(sock->sk);
444 nlk->module = module;
445 out:
446 return err;
447
448 out_module:
449 module_put(module);
450 goto out;
451 }
452
453 static int netlink_release(struct socket *sock)
454 {
455 struct sock *sk = sock->sk;
456 struct netlink_sock *nlk;
457
458 if (!sk)
459 return 0;
460
461 netlink_remove(sk);
462 sock_orphan(sk);
463 nlk = nlk_sk(sk);
464
465 /*
466 * OK. Socket is unlinked, any packets that arrive now
467 * will be purged.
468 */
469
470 sock->sk = NULL;
471 wake_up_interruptible_all(&nlk->wait);
472
473 skb_queue_purge(&sk->sk_write_queue);
474
475 if (nlk->pid && !nlk->subscriptions) {
476 struct netlink_notify n = {
477 .protocol = sk->sk_protocol,
478 .pid = nlk->pid,
479 };
480 atomic_notifier_call_chain(&netlink_chain,
481 NETLINK_URELEASE, &n);
482 }
483
484 module_put(nlk->module);
485
486 netlink_table_grab();
487 if (nlk->flags & NETLINK_KERNEL_SOCKET) {
488 kfree(nl_table[sk->sk_protocol].listeners);
489 nl_table[sk->sk_protocol].module = NULL;
490 nl_table[sk->sk_protocol].registered = 0;
491 } else if (nlk->subscriptions)
492 netlink_update_listeners(sk);
493 netlink_table_ungrab();
494
495 kfree(nlk->groups);
496 nlk->groups = NULL;
497
498 sock_put(sk);
499 return 0;
500 }
501
502 static int netlink_autobind(struct socket *sock)
503 {
504 struct sock *sk = sock->sk;
505 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
506 struct hlist_head *head;
507 struct sock *osk;
508 struct hlist_node *node;
509 s32 pid = current->tgid;
510 int err;
511 static s32 rover = -4097;
512
513 retry:
514 cond_resched();
515 netlink_table_grab();
516 head = nl_pid_hashfn(hash, pid);
517 sk_for_each(osk, node, head) {
518 if (nlk_sk(osk)->pid == pid) {
519 /* Bind collision, search negative pid values. */
520 pid = rover--;
521 if (rover > -4097)
522 rover = -4097;
523 netlink_table_ungrab();
524 goto retry;
525 }
526 }
527 netlink_table_ungrab();
528
529 err = netlink_insert(sk, pid);
530 if (err == -EADDRINUSE)
531 goto retry;
532
533 /* If 2 threads race to autobind, that is fine. */
534 if (err == -EBUSY)
535 err = 0;
536
537 return err;
538 }
539
540 static inline int netlink_capable(struct socket *sock, unsigned int flag)
541 {
542 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
543 capable(CAP_NET_ADMIN);
544 }
545
546 static void
547 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
548 {
549 struct netlink_sock *nlk = nlk_sk(sk);
550
551 if (nlk->subscriptions && !subscriptions)
552 __sk_del_bind_node(sk);
553 else if (!nlk->subscriptions && subscriptions)
554 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
555 nlk->subscriptions = subscriptions;
556 }
557
558 static int netlink_alloc_groups(struct sock *sk)
559 {
560 struct netlink_sock *nlk = nlk_sk(sk);
561 unsigned int groups;
562 int err = 0;
563
564 netlink_lock_table();
565 groups = nl_table[sk->sk_protocol].groups;
566 if (!nl_table[sk->sk_protocol].registered)
567 err = -ENOENT;
568 netlink_unlock_table();
569
570 if (err)
571 return err;
572
573 nlk->groups = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
574 if (nlk->groups == NULL)
575 return -ENOMEM;
576 nlk->ngroups = groups;
577 return 0;
578 }
579
580 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
581 {
582 struct sock *sk = sock->sk;
583 struct netlink_sock *nlk = nlk_sk(sk);
584 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
585 int err;
586
587 if (nladdr->nl_family != AF_NETLINK)
588 return -EINVAL;
589
590 /* Only superuser is allowed to listen multicasts */
591 if (nladdr->nl_groups) {
592 if (!netlink_capable(sock, NL_NONROOT_RECV))
593 return -EPERM;
594 if (nlk->groups == NULL) {
595 err = netlink_alloc_groups(sk);
596 if (err)
597 return err;
598 }
599 }
600
601 if (nlk->pid) {
602 if (nladdr->nl_pid != nlk->pid)
603 return -EINVAL;
604 } else {
605 err = nladdr->nl_pid ?
606 netlink_insert(sk, nladdr->nl_pid) :
607 netlink_autobind(sock);
608 if (err)
609 return err;
610 }
611
612 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
613 return 0;
614
615 netlink_table_grab();
616 netlink_update_subscriptions(sk, nlk->subscriptions +
617 hweight32(nladdr->nl_groups) -
618 hweight32(nlk->groups[0]));
619 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
620 netlink_update_listeners(sk);
621 netlink_table_ungrab();
622
623 return 0;
624 }
625
626 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
627 int alen, int flags)
628 {
629 int err = 0;
630 struct sock *sk = sock->sk;
631 struct netlink_sock *nlk = nlk_sk(sk);
632 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr;
633
634 if (addr->sa_family == AF_UNSPEC) {
635 sk->sk_state = NETLINK_UNCONNECTED;
636 nlk->dst_pid = 0;
637 nlk->dst_group = 0;
638 return 0;
639 }
640 if (addr->sa_family != AF_NETLINK)
641 return -EINVAL;
642
643 /* Only superuser is allowed to send multicasts */
644 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
645 return -EPERM;
646
647 if (!nlk->pid)
648 err = netlink_autobind(sock);
649
650 if (err == 0) {
651 sk->sk_state = NETLINK_CONNECTED;
652 nlk->dst_pid = nladdr->nl_pid;
653 nlk->dst_group = ffs(nladdr->nl_groups);
654 }
655
656 return err;
657 }
658
659 static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer)
660 {
661 struct sock *sk = sock->sk;
662 struct netlink_sock *nlk = nlk_sk(sk);
663 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr;
664
665 nladdr->nl_family = AF_NETLINK;
666 nladdr->nl_pad = 0;
667 *addr_len = sizeof(*nladdr);
668
669 if (peer) {
670 nladdr->nl_pid = nlk->dst_pid;
671 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
672 } else {
673 nladdr->nl_pid = nlk->pid;
674 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
675 }
676 return 0;
677 }
678
679 static void netlink_overrun(struct sock *sk)
680 {
681 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
682 sk->sk_err = ENOBUFS;
683 sk->sk_error_report(sk);
684 }
685 }
686
687 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
688 {
689 int protocol = ssk->sk_protocol;
690 struct sock *sock;
691 struct netlink_sock *nlk;
692
693 sock = netlink_lookup(protocol, pid);
694 if (!sock)
695 return ERR_PTR(-ECONNREFUSED);
696
697 /* Don't bother queuing skb if kernel socket has no input function */
698 nlk = nlk_sk(sock);
699 if ((nlk->pid == 0 && !nlk->data_ready) ||
700 (sock->sk_state == NETLINK_CONNECTED &&
701 nlk->dst_pid != nlk_sk(ssk)->pid)) {
702 sock_put(sock);
703 return ERR_PTR(-ECONNREFUSED);
704 }
705 return sock;
706 }
707
708 struct sock *netlink_getsockbyfilp(struct file *filp)
709 {
710 struct inode *inode = filp->f_path.dentry->d_inode;
711 struct sock *sock;
712
713 if (!S_ISSOCK(inode->i_mode))
714 return ERR_PTR(-ENOTSOCK);
715
716 sock = SOCKET_I(inode)->sk;
717 if (sock->sk_family != AF_NETLINK)
718 return ERR_PTR(-EINVAL);
719
720 sock_hold(sock);
721 return sock;
722 }
723
724 /*
725 * Attach a skb to a netlink socket.
726 * The caller must hold a reference to the destination socket. On error, the
727 * reference is dropped. The skb is not send to the destination, just all
728 * all error checks are performed and memory in the queue is reserved.
729 * Return values:
730 * < 0: error. skb freed, reference to sock dropped.
731 * 0: continue
732 * 1: repeat lookup - reference dropped while waiting for socket memory.
733 */
734 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock,
735 long timeo, struct sock *ssk)
736 {
737 struct netlink_sock *nlk;
738
739 nlk = nlk_sk(sk);
740
741 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
742 test_bit(0, &nlk->state)) {
743 DECLARE_WAITQUEUE(wait, current);
744 if (!timeo) {
745 if (!ssk || nlk_sk(ssk)->pid == 0)
746 netlink_overrun(sk);
747 sock_put(sk);
748 kfree_skb(skb);
749 return -EAGAIN;
750 }
751
752 __set_current_state(TASK_INTERRUPTIBLE);
753 add_wait_queue(&nlk->wait, &wait);
754
755 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
756 test_bit(0, &nlk->state)) &&
757 !sock_flag(sk, SOCK_DEAD))
758 timeo = schedule_timeout(timeo);
759
760 __set_current_state(TASK_RUNNING);
761 remove_wait_queue(&nlk->wait, &wait);
762 sock_put(sk);
763
764 if (signal_pending(current)) {
765 kfree_skb(skb);
766 return sock_intr_errno(timeo);
767 }
768 return 1;
769 }
770 skb_set_owner_r(skb, sk);
771 return 0;
772 }
773
774 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol)
775 {
776 int len = skb->len;
777
778 skb_queue_tail(&sk->sk_receive_queue, skb);
779 sk->sk_data_ready(sk, len);
780 sock_put(sk);
781 return len;
782 }
783
784 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
785 {
786 kfree_skb(skb);
787 sock_put(sk);
788 }
789
790 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
791 gfp_t allocation)
792 {
793 int delta;
794
795 skb_orphan(skb);
796
797 delta = skb->end - skb->tail;
798 if (delta * 2 < skb->truesize)
799 return skb;
800
801 if (skb_shared(skb)) {
802 struct sk_buff *nskb = skb_clone(skb, allocation);
803 if (!nskb)
804 return skb;
805 kfree_skb(skb);
806 skb = nskb;
807 }
808
809 if (!pskb_expand_head(skb, 0, -delta, allocation))
810 skb->truesize -= delta;
811
812 return skb;
813 }
814
815 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock)
816 {
817 struct sock *sk;
818 int err;
819 long timeo;
820
821 skb = netlink_trim(skb, gfp_any());
822
823 timeo = sock_sndtimeo(ssk, nonblock);
824 retry:
825 sk = netlink_getsockbypid(ssk, pid);
826 if (IS_ERR(sk)) {
827 kfree_skb(skb);
828 return PTR_ERR(sk);
829 }
830 err = netlink_attachskb(sk, skb, nonblock, timeo, ssk);
831 if (err == 1)
832 goto retry;
833 if (err)
834 return err;
835
836 return netlink_sendskb(sk, skb, ssk->sk_protocol);
837 }
838
839 int netlink_has_listeners(struct sock *sk, unsigned int group)
840 {
841 int res = 0;
842
843 BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET));
844 if (group - 1 < nl_table[sk->sk_protocol].groups)
845 res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners);
846 return res;
847 }
848 EXPORT_SYMBOL_GPL(netlink_has_listeners);
849
850 static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
851 {
852 struct netlink_sock *nlk = nlk_sk(sk);
853
854 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
855 !test_bit(0, &nlk->state)) {
856 skb_set_owner_r(skb, sk);
857 skb_queue_tail(&sk->sk_receive_queue, skb);
858 sk->sk_data_ready(sk, skb->len);
859 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
860 }
861 return -1;
862 }
863
864 struct netlink_broadcast_data {
865 struct sock *exclude_sk;
866 u32 pid;
867 u32 group;
868 int failure;
869 int congested;
870 int delivered;
871 gfp_t allocation;
872 struct sk_buff *skb, *skb2;
873 };
874
875 static inline int do_one_broadcast(struct sock *sk,
876 struct netlink_broadcast_data *p)
877 {
878 struct netlink_sock *nlk = nlk_sk(sk);
879 int val;
880
881 if (p->exclude_sk == sk)
882 goto out;
883
884 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
885 !test_bit(p->group - 1, nlk->groups))
886 goto out;
887
888 if (p->failure) {
889 netlink_overrun(sk);
890 goto out;
891 }
892
893 sock_hold(sk);
894 if (p->skb2 == NULL) {
895 if (skb_shared(p->skb)) {
896 p->skb2 = skb_clone(p->skb, p->allocation);
897 } else {
898 p->skb2 = skb_get(p->skb);
899 /*
900 * skb ownership may have been set when
901 * delivered to a previous socket.
902 */
903 skb_orphan(p->skb2);
904 }
905 }
906 if (p->skb2 == NULL) {
907 netlink_overrun(sk);
908 /* Clone failed. Notify ALL listeners. */
909 p->failure = 1;
910 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
911 netlink_overrun(sk);
912 } else {
913 p->congested |= val;
914 p->delivered = 1;
915 p->skb2 = NULL;
916 }
917 sock_put(sk);
918
919 out:
920 return 0;
921 }
922
923 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
924 u32 group, gfp_t allocation)
925 {
926 struct netlink_broadcast_data info;
927 struct hlist_node *node;
928 struct sock *sk;
929
930 skb = netlink_trim(skb, allocation);
931
932 info.exclude_sk = ssk;
933 info.pid = pid;
934 info.group = group;
935 info.failure = 0;
936 info.congested = 0;
937 info.delivered = 0;
938 info.allocation = allocation;
939 info.skb = skb;
940 info.skb2 = NULL;
941
942 /* While we sleep in clone, do not allow to change socket list */
943
944 netlink_lock_table();
945
946 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
947 do_one_broadcast(sk, &info);
948
949 kfree_skb(skb);
950
951 netlink_unlock_table();
952
953 if (info.skb2)
954 kfree_skb(info.skb2);
955
956 if (info.delivered) {
957 if (info.congested && (allocation & __GFP_WAIT))
958 yield();
959 return 0;
960 }
961 if (info.failure)
962 return -ENOBUFS;
963 return -ESRCH;
964 }
965
966 struct netlink_set_err_data {
967 struct sock *exclude_sk;
968 u32 pid;
969 u32 group;
970 int code;
971 };
972
973 static inline int do_one_set_err(struct sock *sk,
974 struct netlink_set_err_data *p)
975 {
976 struct netlink_sock *nlk = nlk_sk(sk);
977
978 if (sk == p->exclude_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 sk->sk_err = p->code;
986 sk->sk_error_report(sk);
987 out:
988 return 0;
989 }
990
991 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
992 {
993 struct netlink_set_err_data info;
994 struct hlist_node *node;
995 struct sock *sk;
996
997 info.exclude_sk = ssk;
998 info.pid = pid;
999 info.group = group;
1000 info.code = code;
1001
1002 read_lock(&nl_table_lock);
1003
1004 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1005 do_one_set_err(sk, &info);
1006
1007 read_unlock(&nl_table_lock);
1008 }
1009
1010 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1011 char __user *optval, int optlen)
1012 {
1013 struct sock *sk = sock->sk;
1014 struct netlink_sock *nlk = nlk_sk(sk);
1015 int val = 0, err;
1016
1017 if (level != SOL_NETLINK)
1018 return -ENOPROTOOPT;
1019
1020 if (optlen >= sizeof(int) &&
1021 get_user(val, (int __user *)optval))
1022 return -EFAULT;
1023
1024 switch (optname) {
1025 case NETLINK_PKTINFO:
1026 if (val)
1027 nlk->flags |= NETLINK_RECV_PKTINFO;
1028 else
1029 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1030 err = 0;
1031 break;
1032 case NETLINK_ADD_MEMBERSHIP:
1033 case NETLINK_DROP_MEMBERSHIP: {
1034 unsigned int subscriptions;
1035 int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0;
1036
1037 if (!netlink_capable(sock, NL_NONROOT_RECV))
1038 return -EPERM;
1039 if (nlk->groups == NULL) {
1040 err = netlink_alloc_groups(sk);
1041 if (err)
1042 return err;
1043 }
1044 if (!val || val - 1 >= nlk->ngroups)
1045 return -EINVAL;
1046 netlink_table_grab();
1047 old = test_bit(val - 1, nlk->groups);
1048 subscriptions = nlk->subscriptions - old + new;
1049 if (new)
1050 __set_bit(val - 1, nlk->groups);
1051 else
1052 __clear_bit(val - 1, nlk->groups);
1053 netlink_update_subscriptions(sk, subscriptions);
1054 netlink_update_listeners(sk);
1055 netlink_table_ungrab();
1056 err = 0;
1057 break;
1058 }
1059 default:
1060 err = -ENOPROTOOPT;
1061 }
1062 return err;
1063 }
1064
1065 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1066 char __user *optval, int __user *optlen)
1067 {
1068 struct sock *sk = sock->sk;
1069 struct netlink_sock *nlk = nlk_sk(sk);
1070 int len, val, err;
1071
1072 if (level != SOL_NETLINK)
1073 return -ENOPROTOOPT;
1074
1075 if (get_user(len, optlen))
1076 return -EFAULT;
1077 if (len < 0)
1078 return -EINVAL;
1079
1080 switch (optname) {
1081 case NETLINK_PKTINFO:
1082 if (len < sizeof(int))
1083 return -EINVAL;
1084 len = sizeof(int);
1085 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1086 if (put_user(len, optlen) ||
1087 put_user(val, optval))
1088 return -EFAULT;
1089 err = 0;
1090 break;
1091 default:
1092 err = -ENOPROTOOPT;
1093 }
1094 return err;
1095 }
1096
1097 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1098 {
1099 struct nl_pktinfo info;
1100
1101 info.group = NETLINK_CB(skb).dst_group;
1102 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1103 }
1104
1105 static inline void netlink_rcv_wake(struct sock *sk)
1106 {
1107 struct netlink_sock *nlk = nlk_sk(sk);
1108
1109 if (skb_queue_empty(&sk->sk_receive_queue))
1110 clear_bit(0, &nlk->state);
1111 if (!test_bit(0, &nlk->state))
1112 wake_up_interruptible(&nlk->wait);
1113 }
1114
1115 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1116 struct msghdr *msg, size_t len)
1117 {
1118 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1119 struct sock *sk = sock->sk;
1120 struct netlink_sock *nlk = nlk_sk(sk);
1121 struct sockaddr_nl *addr=msg->msg_name;
1122 u32 dst_pid;
1123 u32 dst_group;
1124 struct sk_buff *skb;
1125 int err;
1126 struct scm_cookie scm;
1127
1128 if (msg->msg_flags&MSG_OOB)
1129 return -EOPNOTSUPP;
1130
1131 if (NULL == siocb->scm)
1132 siocb->scm = &scm;
1133 err = scm_send(sock, msg, siocb->scm);
1134 if (err < 0)
1135 return err;
1136
1137 if (msg->msg_namelen) {
1138 if (addr->nl_family != AF_NETLINK)
1139 return -EINVAL;
1140 dst_pid = addr->nl_pid;
1141 dst_group = ffs(addr->nl_groups);
1142 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1143 return -EPERM;
1144 } else {
1145 dst_pid = nlk->dst_pid;
1146 dst_group = nlk->dst_group;
1147 }
1148
1149 if (!nlk->pid) {
1150 err = netlink_autobind(sock);
1151 if (err)
1152 goto out;
1153 }
1154
1155 err = -EMSGSIZE;
1156 if (len > sk->sk_sndbuf - 32)
1157 goto out;
1158 err = -ENOBUFS;
1159 skb = alloc_skb(len, GFP_KERNEL);
1160 if (skb==NULL)
1161 goto out;
1162
1163 NETLINK_CB(skb).pid = nlk->pid;
1164 NETLINK_CB(skb).dst_group = dst_group;
1165 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
1166 selinux_get_task_sid(current, &(NETLINK_CB(skb).sid));
1167 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1168
1169 /* What can I do? Netlink is asynchronous, so that
1170 we will have to save current capabilities to
1171 check them, when this message will be delivered
1172 to corresponding kernel module. --ANK (980802)
1173 */
1174
1175 err = -EFAULT;
1176 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) {
1177 kfree_skb(skb);
1178 goto out;
1179 }
1180
1181 err = security_netlink_send(sk, skb);
1182 if (err) {
1183 kfree_skb(skb);
1184 goto out;
1185 }
1186
1187 if (dst_group) {
1188 atomic_inc(&skb->users);
1189 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1190 }
1191 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1192
1193 out:
1194 return err;
1195 }
1196
1197 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1198 struct msghdr *msg, size_t len,
1199 int flags)
1200 {
1201 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1202 struct scm_cookie scm;
1203 struct sock *sk = sock->sk;
1204 struct netlink_sock *nlk = nlk_sk(sk);
1205 int noblock = flags&MSG_DONTWAIT;
1206 size_t copied;
1207 struct sk_buff *skb;
1208 int err;
1209
1210 if (flags&MSG_OOB)
1211 return -EOPNOTSUPP;
1212
1213 copied = 0;
1214
1215 skb = skb_recv_datagram(sk,flags,noblock,&err);
1216 if (skb==NULL)
1217 goto out;
1218
1219 msg->msg_namelen = 0;
1220
1221 copied = skb->len;
1222 if (len < copied) {
1223 msg->msg_flags |= MSG_TRUNC;
1224 copied = len;
1225 }
1226
1227 skb_reset_transport_header(skb);
1228 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1229
1230 if (msg->msg_name) {
1231 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name;
1232 addr->nl_family = AF_NETLINK;
1233 addr->nl_pad = 0;
1234 addr->nl_pid = NETLINK_CB(skb).pid;
1235 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1236 msg->msg_namelen = sizeof(*addr);
1237 }
1238
1239 if (nlk->flags & NETLINK_RECV_PKTINFO)
1240 netlink_cmsg_recv_pktinfo(msg, skb);
1241
1242 if (NULL == siocb->scm) {
1243 memset(&scm, 0, sizeof(scm));
1244 siocb->scm = &scm;
1245 }
1246 siocb->scm->creds = *NETLINK_CREDS(skb);
1247 if (flags & MSG_TRUNC)
1248 copied = skb->len;
1249 skb_free_datagram(sk, skb);
1250
1251 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1252 netlink_dump(sk);
1253
1254 scm_recv(sock, msg, siocb->scm, flags);
1255 out:
1256 netlink_rcv_wake(sk);
1257 return err ? : copied;
1258 }
1259
1260 static void netlink_data_ready(struct sock *sk, int len)
1261 {
1262 struct netlink_sock *nlk = nlk_sk(sk);
1263
1264 if (nlk->data_ready)
1265 nlk->data_ready(sk, len);
1266 netlink_rcv_wake(sk);
1267 }
1268
1269 /*
1270 * We export these functions to other modules. They provide a
1271 * complete set of kernel non-blocking support for message
1272 * queueing.
1273 */
1274
1275 struct sock *
1276 netlink_kernel_create(int unit, unsigned int groups,
1277 void (*input)(struct sock *sk, int len),
1278 struct mutex *cb_mutex, struct module *module)
1279 {
1280 struct socket *sock;
1281 struct sock *sk;
1282 struct netlink_sock *nlk;
1283 unsigned long *listeners = NULL;
1284
1285 BUG_ON(!nl_table);
1286
1287 if (unit<0 || unit>=MAX_LINKS)
1288 return NULL;
1289
1290 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1291 return NULL;
1292
1293 if (__netlink_create(sock, cb_mutex, unit) < 0)
1294 goto out_sock_release;
1295
1296 if (groups < 32)
1297 groups = 32;
1298
1299 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
1300 if (!listeners)
1301 goto out_sock_release;
1302
1303 sk = sock->sk;
1304 sk->sk_data_ready = netlink_data_ready;
1305 if (input)
1306 nlk_sk(sk)->data_ready = input;
1307
1308 if (netlink_insert(sk, 0))
1309 goto out_sock_release;
1310
1311 nlk = nlk_sk(sk);
1312 nlk->flags |= NETLINK_KERNEL_SOCKET;
1313
1314 netlink_table_grab();
1315 nl_table[unit].groups = groups;
1316 nl_table[unit].listeners = listeners;
1317 nl_table[unit].cb_mutex = cb_mutex;
1318 nl_table[unit].module = module;
1319 nl_table[unit].registered = 1;
1320 netlink_table_ungrab();
1321
1322 return sk;
1323
1324 out_sock_release:
1325 kfree(listeners);
1326 sock_release(sock);
1327 return NULL;
1328 }
1329
1330 void netlink_set_nonroot(int protocol, unsigned int flags)
1331 {
1332 if ((unsigned int)protocol < MAX_LINKS)
1333 nl_table[protocol].nl_nonroot = flags;
1334 }
1335
1336 static void netlink_destroy_callback(struct netlink_callback *cb)
1337 {
1338 if (cb->skb)
1339 kfree_skb(cb->skb);
1340 kfree(cb);
1341 }
1342
1343 /*
1344 * It looks a bit ugly.
1345 * It would be better to create kernel thread.
1346 */
1347
1348 static int netlink_dump(struct sock *sk)
1349 {
1350 struct netlink_sock *nlk = nlk_sk(sk);
1351 struct netlink_callback *cb;
1352 struct sk_buff *skb;
1353 struct nlmsghdr *nlh;
1354 int len, err = -ENOBUFS;
1355
1356 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1357 if (!skb)
1358 goto errout;
1359
1360 mutex_lock(nlk->cb_mutex);
1361
1362 cb = nlk->cb;
1363 if (cb == NULL) {
1364 err = -EINVAL;
1365 goto errout_skb;
1366 }
1367
1368 len = cb->dump(skb, cb);
1369
1370 if (len > 0) {
1371 mutex_unlock(nlk->cb_mutex);
1372 skb_queue_tail(&sk->sk_receive_queue, skb);
1373 sk->sk_data_ready(sk, len);
1374 return 0;
1375 }
1376
1377 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1378 if (!nlh)
1379 goto errout_skb;
1380
1381 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1382
1383 skb_queue_tail(&sk->sk_receive_queue, skb);
1384 sk->sk_data_ready(sk, skb->len);
1385
1386 if (cb->done)
1387 cb->done(cb);
1388 nlk->cb = NULL;
1389 mutex_unlock(nlk->cb_mutex);
1390
1391 netlink_destroy_callback(cb);
1392 return 0;
1393
1394 errout_skb:
1395 mutex_unlock(nlk->cb_mutex);
1396 kfree_skb(skb);
1397 errout:
1398 return err;
1399 }
1400
1401 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1402 struct nlmsghdr *nlh,
1403 int (*dump)(struct sk_buff *skb, struct netlink_callback*),
1404 int (*done)(struct netlink_callback*))
1405 {
1406 struct netlink_callback *cb;
1407 struct sock *sk;
1408 struct netlink_sock *nlk;
1409
1410 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1411 if (cb == NULL)
1412 return -ENOBUFS;
1413
1414 cb->dump = dump;
1415 cb->done = done;
1416 cb->nlh = nlh;
1417 atomic_inc(&skb->users);
1418 cb->skb = skb;
1419
1420 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid);
1421 if (sk == NULL) {
1422 netlink_destroy_callback(cb);
1423 return -ECONNREFUSED;
1424 }
1425 nlk = nlk_sk(sk);
1426 /* A dump is in progress... */
1427 mutex_lock(nlk->cb_mutex);
1428 if (nlk->cb) {
1429 mutex_unlock(nlk->cb_mutex);
1430 netlink_destroy_callback(cb);
1431 sock_put(sk);
1432 return -EBUSY;
1433 }
1434 nlk->cb = cb;
1435 mutex_unlock(nlk->cb_mutex);
1436
1437 netlink_dump(sk);
1438 sock_put(sk);
1439
1440 /* We successfully started a dump, by returning -EINTR we
1441 * signal the queue mangement to interrupt processing of
1442 * any netlink messages so userspace gets a chance to read
1443 * the results. */
1444 return -EINTR;
1445 }
1446
1447 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1448 {
1449 struct sk_buff *skb;
1450 struct nlmsghdr *rep;
1451 struct nlmsgerr *errmsg;
1452 size_t payload = sizeof(*errmsg);
1453
1454 /* error messages get the original request appened */
1455 if (err)
1456 payload += nlmsg_len(nlh);
1457
1458 skb = nlmsg_new(payload, GFP_KERNEL);
1459 if (!skb) {
1460 struct sock *sk;
1461
1462 sk = netlink_lookup(in_skb->sk->sk_protocol,
1463 NETLINK_CB(in_skb).pid);
1464 if (sk) {
1465 sk->sk_err = ENOBUFS;
1466 sk->sk_error_report(sk);
1467 sock_put(sk);
1468 }
1469 return;
1470 }
1471
1472 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1473 NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
1474 errmsg = nlmsg_data(rep);
1475 errmsg->error = err;
1476 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1477 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1478 }
1479
1480 static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1481 struct nlmsghdr *))
1482 {
1483 struct nlmsghdr *nlh;
1484 int err;
1485
1486 while (skb->len >= nlmsg_total_size(0)) {
1487 nlh = nlmsg_hdr(skb);
1488 err = 0;
1489
1490 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1491 return 0;
1492
1493 /* Only requests are handled by the kernel */
1494 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1495 goto skip;
1496
1497 /* Skip control messages */
1498 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1499 goto skip;
1500
1501 err = cb(skb, nlh);
1502 if (err == -EINTR) {
1503 /* Not an error, but we interrupt processing */
1504 netlink_queue_skip(nlh, skb);
1505 return err;
1506 }
1507 skip:
1508 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1509 netlink_ack(skb, nlh, err);
1510
1511 netlink_queue_skip(nlh, skb);
1512 }
1513
1514 return 0;
1515 }
1516
1517 /**
1518 * nelink_run_queue - Process netlink receive queue.
1519 * @sk: Netlink socket containing the queue
1520 * @qlen: Place to store queue length upon entry
1521 * @cb: Callback function invoked for each netlink message found
1522 *
1523 * Processes as much as there was in the queue upon entry and invokes
1524 * a callback function for each netlink message found. The callback
1525 * function may refuse a message by returning a negative error code
1526 * but setting the error pointer to 0 in which case this function
1527 * returns with a qlen != 0.
1528 *
1529 * qlen must be initialized to 0 before the initial entry, afterwards
1530 * the function may be called repeatedly until qlen reaches 0.
1531 *
1532 * The callback function may return -EINTR to signal that processing
1533 * of netlink messages shall be interrupted. In this case the message
1534 * currently being processed will NOT be requeued onto the receive
1535 * queue.
1536 */
1537 void netlink_run_queue(struct sock *sk, unsigned int *qlen,
1538 int (*cb)(struct sk_buff *, struct nlmsghdr *))
1539 {
1540 struct sk_buff *skb;
1541
1542 if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue))
1543 *qlen = skb_queue_len(&sk->sk_receive_queue);
1544
1545 for (; *qlen; (*qlen)--) {
1546 skb = skb_dequeue(&sk->sk_receive_queue);
1547 if (netlink_rcv_skb(skb, cb)) {
1548 if (skb->len)
1549 skb_queue_head(&sk->sk_receive_queue, skb);
1550 else {
1551 kfree_skb(skb);
1552 (*qlen)--;
1553 }
1554 break;
1555 }
1556
1557 kfree_skb(skb);
1558 }
1559 }
1560
1561 /**
1562 * netlink_queue_skip - Skip netlink message while processing queue.
1563 * @nlh: Netlink message to be skipped
1564 * @skb: Socket buffer containing the netlink messages.
1565 *
1566 * Pulls the given netlink message off the socket buffer so the next
1567 * call to netlink_queue_run() will not reconsider the message.
1568 */
1569 static void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb)
1570 {
1571 int msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1572
1573 if (msglen > skb->len)
1574 msglen = skb->len;
1575
1576 skb_pull(skb, msglen);
1577 }
1578
1579 /**
1580 * nlmsg_notify - send a notification netlink message
1581 * @sk: netlink socket to use
1582 * @skb: notification message
1583 * @pid: destination netlink pid for reports or 0
1584 * @group: destination multicast group or 0
1585 * @report: 1 to report back, 0 to disable
1586 * @flags: allocation flags
1587 */
1588 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1589 unsigned int group, int report, gfp_t flags)
1590 {
1591 int err = 0;
1592
1593 if (group) {
1594 int exclude_pid = 0;
1595
1596 if (report) {
1597 atomic_inc(&skb->users);
1598 exclude_pid = pid;
1599 }
1600
1601 /* errors reported via destination sk->sk_err */
1602 nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1603 }
1604
1605 if (report)
1606 err = nlmsg_unicast(sk, skb, pid);
1607
1608 return err;
1609 }
1610
1611 #ifdef CONFIG_PROC_FS
1612 struct nl_seq_iter {
1613 int link;
1614 int hash_idx;
1615 };
1616
1617 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1618 {
1619 struct nl_seq_iter *iter = seq->private;
1620 int i, j;
1621 struct sock *s;
1622 struct hlist_node *node;
1623 loff_t off = 0;
1624
1625 for (i=0; i<MAX_LINKS; i++) {
1626 struct nl_pid_hash *hash = &nl_table[i].hash;
1627
1628 for (j = 0; j <= hash->mask; j++) {
1629 sk_for_each(s, node, &hash->table[j]) {
1630 if (off == pos) {
1631 iter->link = i;
1632 iter->hash_idx = j;
1633 return s;
1634 }
1635 ++off;
1636 }
1637 }
1638 }
1639 return NULL;
1640 }
1641
1642 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1643 {
1644 read_lock(&nl_table_lock);
1645 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1646 }
1647
1648 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1649 {
1650 struct sock *s;
1651 struct nl_seq_iter *iter;
1652 int i, j;
1653
1654 ++*pos;
1655
1656 if (v == SEQ_START_TOKEN)
1657 return netlink_seq_socket_idx(seq, 0);
1658
1659 s = sk_next(v);
1660 if (s)
1661 return s;
1662
1663 iter = seq->private;
1664 i = iter->link;
1665 j = iter->hash_idx + 1;
1666
1667 do {
1668 struct nl_pid_hash *hash = &nl_table[i].hash;
1669
1670 for (; j <= hash->mask; j++) {
1671 s = sk_head(&hash->table[j]);
1672 if (s) {
1673 iter->link = i;
1674 iter->hash_idx = j;
1675 return s;
1676 }
1677 }
1678
1679 j = 0;
1680 } while (++i < MAX_LINKS);
1681
1682 return NULL;
1683 }
1684
1685 static void netlink_seq_stop(struct seq_file *seq, void *v)
1686 {
1687 read_unlock(&nl_table_lock);
1688 }
1689
1690
1691 static int netlink_seq_show(struct seq_file *seq, void *v)
1692 {
1693 if (v == SEQ_START_TOKEN)
1694 seq_puts(seq,
1695 "sk Eth Pid Groups "
1696 "Rmem Wmem Dump Locks\n");
1697 else {
1698 struct sock *s = v;
1699 struct netlink_sock *nlk = nlk_sk(s);
1700
1701 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
1702 s,
1703 s->sk_protocol,
1704 nlk->pid,
1705 nlk->groups ? (u32)nlk->groups[0] : 0,
1706 atomic_read(&s->sk_rmem_alloc),
1707 atomic_read(&s->sk_wmem_alloc),
1708 nlk->cb,
1709 atomic_read(&s->sk_refcnt)
1710 );
1711
1712 }
1713 return 0;
1714 }
1715
1716 static const struct seq_operations netlink_seq_ops = {
1717 .start = netlink_seq_start,
1718 .next = netlink_seq_next,
1719 .stop = netlink_seq_stop,
1720 .show = netlink_seq_show,
1721 };
1722
1723
1724 static int netlink_seq_open(struct inode *inode, struct file *file)
1725 {
1726 struct seq_file *seq;
1727 struct nl_seq_iter *iter;
1728 int err;
1729
1730 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1731 if (!iter)
1732 return -ENOMEM;
1733
1734 err = seq_open(file, &netlink_seq_ops);
1735 if (err) {
1736 kfree(iter);
1737 return err;
1738 }
1739
1740 seq = file->private_data;
1741 seq->private = iter;
1742 return 0;
1743 }
1744
1745 static const struct file_operations netlink_seq_fops = {
1746 .owner = THIS_MODULE,
1747 .open = netlink_seq_open,
1748 .read = seq_read,
1749 .llseek = seq_lseek,
1750 .release = seq_release_private,
1751 };
1752
1753 #endif
1754
1755 int netlink_register_notifier(struct notifier_block *nb)
1756 {
1757 return atomic_notifier_chain_register(&netlink_chain, nb);
1758 }
1759
1760 int netlink_unregister_notifier(struct notifier_block *nb)
1761 {
1762 return atomic_notifier_chain_unregister(&netlink_chain, nb);
1763 }
1764
1765 static const struct proto_ops netlink_ops = {
1766 .family = PF_NETLINK,
1767 .owner = THIS_MODULE,
1768 .release = netlink_release,
1769 .bind = netlink_bind,
1770 .connect = netlink_connect,
1771 .socketpair = sock_no_socketpair,
1772 .accept = sock_no_accept,
1773 .getname = netlink_getname,
1774 .poll = datagram_poll,
1775 .ioctl = sock_no_ioctl,
1776 .listen = sock_no_listen,
1777 .shutdown = sock_no_shutdown,
1778 .setsockopt = netlink_setsockopt,
1779 .getsockopt = netlink_getsockopt,
1780 .sendmsg = netlink_sendmsg,
1781 .recvmsg = netlink_recvmsg,
1782 .mmap = sock_no_mmap,
1783 .sendpage = sock_no_sendpage,
1784 };
1785
1786 static struct net_proto_family netlink_family_ops = {
1787 .family = PF_NETLINK,
1788 .create = netlink_create,
1789 .owner = THIS_MODULE, /* for consistency 8) */
1790 };
1791
1792 static int __init netlink_proto_init(void)
1793 {
1794 struct sk_buff *dummy_skb;
1795 int i;
1796 unsigned long max;
1797 unsigned int order;
1798 int err = proto_register(&netlink_proto, 0);
1799
1800 if (err != 0)
1801 goto out;
1802
1803 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
1804
1805 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
1806 if (!nl_table)
1807 goto panic;
1808
1809 if (num_physpages >= (128 * 1024))
1810 max = num_physpages >> (21 - PAGE_SHIFT);
1811 else
1812 max = num_physpages >> (23 - PAGE_SHIFT);
1813
1814 order = get_bitmask_order(max) - 1 + PAGE_SHIFT;
1815 max = (1UL << order) / sizeof(struct hlist_head);
1816 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1;
1817
1818 for (i = 0; i < MAX_LINKS; i++) {
1819 struct nl_pid_hash *hash = &nl_table[i].hash;
1820
1821 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table));
1822 if (!hash->table) {
1823 while (i-- > 0)
1824 nl_pid_hash_free(nl_table[i].hash.table,
1825 1 * sizeof(*hash->table));
1826 kfree(nl_table);
1827 goto panic;
1828 }
1829 memset(hash->table, 0, 1 * sizeof(*hash->table));
1830 hash->max_shift = order;
1831 hash->shift = 0;
1832 hash->mask = 0;
1833 hash->rehash_time = jiffies;
1834 }
1835
1836 sock_register(&netlink_family_ops);
1837 #ifdef CONFIG_PROC_FS
1838 proc_net_fops_create("netlink", 0, &netlink_seq_fops);
1839 #endif
1840 /* The netlink device handler may be needed early. */
1841 rtnetlink_init();
1842 out:
1843 return err;
1844 panic:
1845 panic("netlink_init: Cannot allocate nl_table\n");
1846 }
1847
1848 core_initcall(netlink_proto_init);
1849
1850 EXPORT_SYMBOL(netlink_ack);
1851 EXPORT_SYMBOL(netlink_run_queue);
1852 EXPORT_SYMBOL(netlink_broadcast);
1853 EXPORT_SYMBOL(netlink_dump_start);
1854 EXPORT_SYMBOL(netlink_kernel_create);
1855 EXPORT_SYMBOL(netlink_register_notifier);
1856 EXPORT_SYMBOL(netlink_set_nonroot);
1857 EXPORT_SYMBOL(netlink_unicast);
1858 EXPORT_SYMBOL(netlink_unregister_notifier);
1859 EXPORT_SYMBOL(nlmsg_notify);
Linux kernel - Deliverables
This page took 0.079013 seconds and 5 git commands to generate.