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[POWERPC] Remove use of 4level-fixup.h for ppc32
[linux-2.6/cjktty.git] / net / netlink / af_netlink.c
blob507828d7d4aeb807220462a4d494441388ac5624
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 #include <linux/mutex.h>
60
61 #include <net/sock.h>
62 #include <net/scm.h>
63 #include <net/netlink.h>
64
65 #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
66
67 struct netlink_sock {
68 /* struct sock has to be the first member of netlink_sock */
69 struct sock sk;
70 u32 pid;
71 u32 dst_pid;
72 u32 dst_group;
73 u32 flags;
74 u32 subscriptions;
75 u32 ngroups;
76 unsigned long *groups;
77 unsigned long state;
78 wait_queue_head_t wait;
79 struct netlink_callback *cb;
80 struct mutex *cb_mutex;
81 struct mutex cb_def_mutex;
82 void (*data_ready)(struct sock *sk, int bytes);
83 struct module *module;
84 };
85
86 #define NETLINK_KERNEL_SOCKET 0x1
87 #define NETLINK_RECV_PKTINFO 0x2
88
89 static inline struct netlink_sock *nlk_sk(struct sock *sk)
90 {
91 return (struct netlink_sock *)sk;
92 }
93
94 struct nl_pid_hash {
95 struct hlist_head *table;
96 unsigned long rehash_time;
97
98 unsigned int mask;
99 unsigned int shift;
100
101 unsigned int entries;
102 unsigned int max_shift;
103
104 u32 rnd;
105 };
106
107 struct netlink_table {
108 struct nl_pid_hash hash;
109 struct hlist_head mc_list;
110 unsigned long *listeners;
111 unsigned int nl_nonroot;
112 unsigned int groups;
113 struct mutex *cb_mutex;
114 struct module *module;
115 int registered;
116 };
117
118 static struct netlink_table *nl_table;
119
120 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
121
122 static int netlink_dump(struct sock *sk);
123 static void netlink_destroy_callback(struct netlink_callback *cb);
124 static void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb);
125
126 static DEFINE_RWLOCK(nl_table_lock);
127 static atomic_t nl_table_users = ATOMIC_INIT(0);
128
129 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
130
131 static u32 netlink_group_mask(u32 group)
132 {
133 return group ? 1 << (group - 1) : 0;
134 }
135
136 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
137 {
138 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
139 }
140
141 static void netlink_sock_destruct(struct sock *sk)
142 {
143 struct netlink_sock *nlk = nlk_sk(sk);
144
145 if (nlk->cb) {
146 if (nlk->cb->done)
147 nlk->cb->done(nlk->cb);
148 netlink_destroy_callback(nlk->cb);
149 }
150
151 skb_queue_purge(&sk->sk_receive_queue);
152
153 if (!sock_flag(sk, SOCK_DEAD)) {
154 printk("Freeing alive netlink socket %p\n", sk);
155 return;
156 }
157 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
158 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
159 BUG_TRAP(!nlk_sk(sk)->groups);
160 }
161
162 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
163 * Look, when several writers sleep and reader wakes them up, all but one
164 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
165 * this, _but_ remember, it adds useless work on UP machines.
166 */
167
168 static void netlink_table_grab(void)
169 {
170 write_lock_irq(&nl_table_lock);
171
172 if (atomic_read(&nl_table_users)) {
173 DECLARE_WAITQUEUE(wait, current);
174
175 add_wait_queue_exclusive(&nl_table_wait, &wait);
176 for(;;) {
177 set_current_state(TASK_UNINTERRUPTIBLE);
178 if (atomic_read(&nl_table_users) == 0)
179 break;
180 write_unlock_irq(&nl_table_lock);
181 schedule();
182 write_lock_irq(&nl_table_lock);
183 }
184
185 __set_current_state(TASK_RUNNING);
186 remove_wait_queue(&nl_table_wait, &wait);
187 }
188 }
189
190 static __inline__ void netlink_table_ungrab(void)
191 {
192 write_unlock_irq(&nl_table_lock);
193 wake_up(&nl_table_wait);
194 }
195
196 static __inline__ void
197 netlink_lock_table(void)
198 {
199 /* read_lock() synchronizes us to netlink_table_grab */
200
201 read_lock(&nl_table_lock);
202 atomic_inc(&nl_table_users);
203 read_unlock(&nl_table_lock);
204 }
205
206 static __inline__ void
207 netlink_unlock_table(void)
208 {
209 if (atomic_dec_and_test(&nl_table_users))
210 wake_up(&nl_table_wait);
211 }
212
213 static __inline__ struct sock *netlink_lookup(int protocol, u32 pid)
214 {
215 struct nl_pid_hash *hash = &nl_table[protocol].hash;
216 struct hlist_head *head;
217 struct sock *sk;
218 struct hlist_node *node;
219
220 read_lock(&nl_table_lock);
221 head = nl_pid_hashfn(hash, pid);
222 sk_for_each(sk, node, head) {
223 if (nlk_sk(sk)->pid == pid) {
224 sock_hold(sk);
225 goto found;
226 }
227 }
228 sk = NULL;
229 found:
230 read_unlock(&nl_table_lock);
231 return sk;
232 }
233
234 static inline struct hlist_head *nl_pid_hash_alloc(size_t size)
235 {
236 if (size <= PAGE_SIZE)
237 return kmalloc(size, GFP_ATOMIC);
238 else
239 return (struct hlist_head *)
240 __get_free_pages(GFP_ATOMIC, get_order(size));
241 }
242
243 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
244 {
245 if (size <= PAGE_SIZE)
246 kfree(table);
247 else
248 free_pages((unsigned long)table, get_order(size));
249 }
250
251 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
252 {
253 unsigned int omask, mask, shift;
254 size_t osize, size;
255 struct hlist_head *otable, *table;
256 int i;
257
258 omask = mask = hash->mask;
259 osize = size = (mask + 1) * sizeof(*table);
260 shift = hash->shift;
261
262 if (grow) {
263 if (++shift > hash->max_shift)
264 return 0;
265 mask = mask * 2 + 1;
266 size *= 2;
267 }
268
269 table = nl_pid_hash_alloc(size);
270 if (!table)
271 return 0;
272
273 memset(table, 0, size);
274 otable = hash->table;
275 hash->table = table;
276 hash->mask = mask;
277 hash->shift = shift;
278 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
279
280 for (i = 0; i <= omask; i++) {
281 struct sock *sk;
282 struct hlist_node *node, *tmp;
283
284 sk_for_each_safe(sk, node, tmp, &otable[i])
285 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
286 }
287
288 nl_pid_hash_free(otable, osize);
289 hash->rehash_time = jiffies + 10 * 60 * HZ;
290 return 1;
291 }
292
293 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
294 {
295 int avg = hash->entries >> hash->shift;
296
297 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
298 return 1;
299
300 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
301 nl_pid_hash_rehash(hash, 0);
302 return 1;
303 }
304
305 return 0;
306 }
307
308 static const struct proto_ops netlink_ops;
309
310 static void
311 netlink_update_listeners(struct sock *sk)
312 {
313 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
314 struct hlist_node *node;
315 unsigned long mask;
316 unsigned int i;
317
318 for (i = 0; i < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) {
319 mask = 0;
320 sk_for_each_bound(sk, node, &tbl->mc_list)
321 mask |= nlk_sk(sk)->groups[i];
322 tbl->listeners[i] = mask;
323 }
324 /* this function is only called with the netlink table "grabbed", which
325 * makes sure updates are visible before bind or setsockopt return. */
326 }
327
328 static int netlink_insert(struct sock *sk, u32 pid)
329 {
330 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
331 struct hlist_head *head;
332 int err = -EADDRINUSE;
333 struct sock *osk;
334 struct hlist_node *node;
335 int len;
336
337 netlink_table_grab();
338 head = nl_pid_hashfn(hash, pid);
339 len = 0;
340 sk_for_each(osk, node, head) {
341 if (nlk_sk(osk)->pid == pid)
342 break;
343 len++;
344 }
345 if (node)
346 goto err;
347
348 err = -EBUSY;
349 if (nlk_sk(sk)->pid)
350 goto err;
351
352 err = -ENOMEM;
353 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
354 goto err;
355
356 if (len && nl_pid_hash_dilute(hash, len))
357 head = nl_pid_hashfn(hash, pid);
358 hash->entries++;
359 nlk_sk(sk)->pid = pid;
360 sk_add_node(sk, head);
361 err = 0;
362
363 err:
364 netlink_table_ungrab();
365 return err;
366 }
367
368 static void netlink_remove(struct sock *sk)
369 {
370 netlink_table_grab();
371 if (sk_del_node_init(sk))
372 nl_table[sk->sk_protocol].hash.entries--;
373 if (nlk_sk(sk)->subscriptions)
374 __sk_del_bind_node(sk);
375 netlink_table_ungrab();
376 }
377
378 static struct proto netlink_proto = {
379 .name = "NETLINK",
380 .owner = THIS_MODULE,
381 .obj_size = sizeof(struct netlink_sock),
382 };
383
384 static int __netlink_create(struct socket *sock, struct mutex *cb_mutex,
385 int protocol)
386 {
387 struct sock *sk;
388 struct netlink_sock *nlk;
389
390 sock->ops = &netlink_ops;
391
392 sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
393 if (!sk)
394 return -ENOMEM;
395
396 sock_init_data(sock, sk);
397
398 nlk = nlk_sk(sk);
399 if (cb_mutex)
400 nlk->cb_mutex = cb_mutex;
401 else {
402 nlk->cb_mutex = &nlk->cb_def_mutex;
403 mutex_init(nlk->cb_mutex);
404 }
405 init_waitqueue_head(&nlk->wait);
406
407 sk->sk_destruct = netlink_sock_destruct;
408 sk->sk_protocol = protocol;
409 return 0;
410 }
411
412 static int netlink_create(struct socket *sock, int protocol)
413 {
414 struct module *module = NULL;
415 struct mutex *cb_mutex;
416 struct netlink_sock *nlk;
417 int err = 0;
418
419 sock->state = SS_UNCONNECTED;
420
421 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
422 return -ESOCKTNOSUPPORT;
423
424 if (protocol<0 || protocol >= MAX_LINKS)
425 return -EPROTONOSUPPORT;
426
427 netlink_lock_table();
428 #ifdef CONFIG_KMOD
429 if (!nl_table[protocol].registered) {
430 netlink_unlock_table();
431 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
432 netlink_lock_table();
433 }
434 #endif
435 if (nl_table[protocol].registered &&
436 try_module_get(nl_table[protocol].module))
437 module = nl_table[protocol].module;
438 cb_mutex = nl_table[protocol].cb_mutex;
439 netlink_unlock_table();
440
441 if ((err = __netlink_create(sock, cb_mutex, protocol)) < 0)
442 goto out_module;
443
444 nlk = nlk_sk(sock->sk);
445 nlk->module = module;
446 out:
447 return err;
448
449 out_module:
450 module_put(module);
451 goto out;
452 }
453
454 static int netlink_release(struct socket *sock)
455 {
456 struct sock *sk = sock->sk;
457 struct netlink_sock *nlk;
458
459 if (!sk)
460 return 0;
461
462 netlink_remove(sk);
463 sock_orphan(sk);
464 nlk = nlk_sk(sk);
465
466 /*
467 * OK. Socket is unlinked, any packets that arrive now
468 * will be purged.
469 */
470
471 sock->sk = NULL;
472 wake_up_interruptible_all(&nlk->wait);
473
474 skb_queue_purge(&sk->sk_write_queue);
475
476 if (nlk->pid && !nlk->subscriptions) {
477 struct netlink_notify n = {
478 .protocol = sk->sk_protocol,
479 .pid = nlk->pid,
480 };
481 atomic_notifier_call_chain(&netlink_chain,
482 NETLINK_URELEASE, &n);
483 }
484
485 module_put(nlk->module);
486
487 netlink_table_grab();
488 if (nlk->flags & NETLINK_KERNEL_SOCKET) {
489 kfree(nl_table[sk->sk_protocol].listeners);
490 nl_table[sk->sk_protocol].module = NULL;
491 nl_table[sk->sk_protocol].registered = 0;
492 } else if (nlk->subscriptions)
493 netlink_update_listeners(sk);
494 netlink_table_ungrab();
495
496 kfree(nlk->groups);
497 nlk->groups = NULL;
498
499 sock_put(sk);
500 return 0;
501 }
502
503 static int netlink_autobind(struct socket *sock)
504 {
505 struct sock *sk = sock->sk;
506 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
507 struct hlist_head *head;
508 struct sock *osk;
509 struct hlist_node *node;
510 s32 pid = current->tgid;
511 int err;
512 static s32 rover = -4097;
513
514 retry:
515 cond_resched();
516 netlink_table_grab();
517 head = nl_pid_hashfn(hash, pid);
518 sk_for_each(osk, node, head) {
519 if (nlk_sk(osk)->pid == pid) {
520 /* Bind collision, search negative pid values. */
521 pid = rover--;
522 if (rover > -4097)
523 rover = -4097;
524 netlink_table_ungrab();
525 goto retry;
526 }
527 }
528 netlink_table_ungrab();
529
530 err = netlink_insert(sk, pid);
531 if (err == -EADDRINUSE)
532 goto retry;
533
534 /* If 2 threads race to autobind, that is fine. */
535 if (err == -EBUSY)
536 err = 0;
537
538 return err;
539 }
540
541 static inline int netlink_capable(struct socket *sock, unsigned int flag)
542 {
543 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
544 capable(CAP_NET_ADMIN);
545 }
546
547 static void
548 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
549 {
550 struct netlink_sock *nlk = nlk_sk(sk);
551
552 if (nlk->subscriptions && !subscriptions)
553 __sk_del_bind_node(sk);
554 else if (!nlk->subscriptions && subscriptions)
555 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
556 nlk->subscriptions = subscriptions;
557 }
558
559 static int netlink_alloc_groups(struct sock *sk)
560 {
561 struct netlink_sock *nlk = nlk_sk(sk);
562 unsigned int groups;
563 int err = 0;
564
565 netlink_lock_table();
566 groups = nl_table[sk->sk_protocol].groups;
567 if (!nl_table[sk->sk_protocol].registered)
568 err = -ENOENT;
569 netlink_unlock_table();
570
571 if (err)
572 return err;
573
574 nlk->groups = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
575 if (nlk->groups == NULL)
576 return -ENOMEM;
577 nlk->ngroups = groups;
578 return 0;
579 }
580
581 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
582 {
583 struct sock *sk = sock->sk;
584 struct netlink_sock *nlk = nlk_sk(sk);
585 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
586 int err;
587
588 if (nladdr->nl_family != AF_NETLINK)
589 return -EINVAL;
590
591 /* Only superuser is allowed to listen multicasts */
592 if (nladdr->nl_groups) {
593 if (!netlink_capable(sock, NL_NONROOT_RECV))
594 return -EPERM;
595 if (nlk->groups == NULL) {
596 err = netlink_alloc_groups(sk);
597 if (err)
598 return err;
599 }
600 }
601
602 if (nlk->pid) {
603 if (nladdr->nl_pid != nlk->pid)
604 return -EINVAL;
605 } else {
606 err = nladdr->nl_pid ?
607 netlink_insert(sk, nladdr->nl_pid) :
608 netlink_autobind(sock);
609 if (err)
610 return err;
611 }
612
613 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
614 return 0;
615
616 netlink_table_grab();
617 netlink_update_subscriptions(sk, nlk->subscriptions +
618 hweight32(nladdr->nl_groups) -
619 hweight32(nlk->groups[0]));
620 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
621 netlink_update_listeners(sk);
622 netlink_table_ungrab();
623
624 return 0;
625 }
626
627 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
628 int alen, int flags)
629 {
630 int err = 0;
631 struct sock *sk = sock->sk;
632 struct netlink_sock *nlk = nlk_sk(sk);
633 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr;
634
635 if (addr->sa_family == AF_UNSPEC) {
636 sk->sk_state = NETLINK_UNCONNECTED;
637 nlk->dst_pid = 0;
638 nlk->dst_group = 0;
639 return 0;
640 }
641 if (addr->sa_family != AF_NETLINK)
642 return -EINVAL;
643
644 /* Only superuser is allowed to send multicasts */
645 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
646 return -EPERM;
647
648 if (!nlk->pid)
649 err = netlink_autobind(sock);
650
651 if (err == 0) {
652 sk->sk_state = NETLINK_CONNECTED;
653 nlk->dst_pid = nladdr->nl_pid;
654 nlk->dst_group = ffs(nladdr->nl_groups);
655 }
656
657 return err;
658 }
659
660 static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer)
661 {
662 struct sock *sk = sock->sk;
663 struct netlink_sock *nlk = nlk_sk(sk);
664 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr;
665
666 nladdr->nl_family = AF_NETLINK;
667 nladdr->nl_pad = 0;
668 *addr_len = sizeof(*nladdr);
669
670 if (peer) {
671 nladdr->nl_pid = nlk->dst_pid;
672 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
673 } else {
674 nladdr->nl_pid = nlk->pid;
675 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
676 }
677 return 0;
678 }
679
680 static void netlink_overrun(struct sock *sk)
681 {
682 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
683 sk->sk_err = ENOBUFS;
684 sk->sk_error_report(sk);
685 }
686 }
687
688 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
689 {
690 int protocol = ssk->sk_protocol;
691 struct sock *sock;
692 struct netlink_sock *nlk;
693
694 sock = netlink_lookup(protocol, pid);
695 if (!sock)
696 return ERR_PTR(-ECONNREFUSED);
697
698 /* Don't bother queuing skb if kernel socket has no input function */
699 nlk = nlk_sk(sock);
700 if ((nlk->pid == 0 && !nlk->data_ready) ||
701 (sock->sk_state == NETLINK_CONNECTED &&
702 nlk->dst_pid != nlk_sk(ssk)->pid)) {
703 sock_put(sock);
704 return ERR_PTR(-ECONNREFUSED);
705 }
706 return sock;
707 }
708
709 struct sock *netlink_getsockbyfilp(struct file *filp)
710 {
711 struct inode *inode = filp->f_path.dentry->d_inode;
712 struct sock *sock;
713
714 if (!S_ISSOCK(inode->i_mode))
715 return ERR_PTR(-ENOTSOCK);
716
717 sock = SOCKET_I(inode)->sk;
718 if (sock->sk_family != AF_NETLINK)
719 return ERR_PTR(-EINVAL);
720
721 sock_hold(sock);
722 return sock;
723 }
724
725 /*
726 * Attach a skb to a netlink socket.
727 * The caller must hold a reference to the destination socket. On error, the
728 * reference is dropped. The skb is not send to the destination, just all
729 * all error checks are performed and memory in the queue is reserved.
730 * Return values:
731 * < 0: error. skb freed, reference to sock dropped.
732 * 0: continue
733 * 1: repeat lookup - reference dropped while waiting for socket memory.
734 */
735 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock,
736 long timeo, struct sock *ssk)
737 {
738 struct netlink_sock *nlk;
739
740 nlk = nlk_sk(sk);
741
742 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
743 test_bit(0, &nlk->state)) {
744 DECLARE_WAITQUEUE(wait, current);
745 if (!timeo) {
746 if (!ssk || nlk_sk(ssk)->pid == 0)
747 netlink_overrun(sk);
748 sock_put(sk);
749 kfree_skb(skb);
750 return -EAGAIN;
751 }
752
753 __set_current_state(TASK_INTERRUPTIBLE);
754 add_wait_queue(&nlk->wait, &wait);
755
756 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
757 test_bit(0, &nlk->state)) &&
758 !sock_flag(sk, SOCK_DEAD))
759 timeo = schedule_timeout(timeo);
760
761 __set_current_state(TASK_RUNNING);
762 remove_wait_queue(&nlk->wait, &wait);
763 sock_put(sk);
764
765 if (signal_pending(current)) {
766 kfree_skb(skb);
767 return sock_intr_errno(timeo);
768 }
769 return 1;
770 }
771 skb_set_owner_r(skb, sk);
772 return 0;
773 }
774
775 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol)
776 {
777 int len = skb->len;
778
779 skb_queue_tail(&sk->sk_receive_queue, skb);
780 sk->sk_data_ready(sk, len);
781 sock_put(sk);
782 return len;
783 }
784
785 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
786 {
787 kfree_skb(skb);
788 sock_put(sk);
789 }
790
791 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
792 gfp_t allocation)
793 {
794 int delta;
795
796 skb_orphan(skb);
797
798 delta = skb->end - skb->tail;
799 if (delta * 2 < skb->truesize)
800 return skb;
801
802 if (skb_shared(skb)) {
803 struct sk_buff *nskb = skb_clone(skb, allocation);
804 if (!nskb)
805 return skb;
806 kfree_skb(skb);
807 skb = nskb;
808 }
809
810 if (!pskb_expand_head(skb, 0, -delta, allocation))
811 skb->truesize -= delta;
812
813 return skb;
814 }
815
816 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock)
817 {
818 struct sock *sk;
819 int err;
820 long timeo;
821
822 skb = netlink_trim(skb, gfp_any());
823
824 timeo = sock_sndtimeo(ssk, nonblock);
825 retry:
826 sk = netlink_getsockbypid(ssk, pid);
827 if (IS_ERR(sk)) {
828 kfree_skb(skb);
829 return PTR_ERR(sk);
830 }
831 err = netlink_attachskb(sk, skb, nonblock, timeo, ssk);
832 if (err == 1)
833 goto retry;
834 if (err)
835 return err;
836
837 return netlink_sendskb(sk, skb, ssk->sk_protocol);
838 }
839
840 int netlink_has_listeners(struct sock *sk, unsigned int group)
841 {
842 int res = 0;
843
844 BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET));
845 if (group - 1 < nl_table[sk->sk_protocol].groups)
846 res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners);
847 return res;
848 }
849 EXPORT_SYMBOL_GPL(netlink_has_listeners);
850
851 static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
852 {
853 struct netlink_sock *nlk = nlk_sk(sk);
854
855 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
856 !test_bit(0, &nlk->state)) {
857 skb_set_owner_r(skb, sk);
858 skb_queue_tail(&sk->sk_receive_queue, skb);
859 sk->sk_data_ready(sk, skb->len);
860 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
861 }
862 return -1;
863 }
864
865 struct netlink_broadcast_data {
866 struct sock *exclude_sk;
867 u32 pid;
868 u32 group;
869 int failure;
870 int congested;
871 int delivered;
872 gfp_t allocation;
873 struct sk_buff *skb, *skb2;
874 };
875
876 static inline int do_one_broadcast(struct sock *sk,
877 struct netlink_broadcast_data *p)
878 {
879 struct netlink_sock *nlk = nlk_sk(sk);
880 int val;
881
882 if (p->exclude_sk == sk)
883 goto out;
884
885 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
886 !test_bit(p->group - 1, nlk->groups))
887 goto out;
888
889 if (p->failure) {
890 netlink_overrun(sk);
891 goto out;
892 }
893
894 sock_hold(sk);
895 if (p->skb2 == NULL) {
896 if (skb_shared(p->skb)) {
897 p->skb2 = skb_clone(p->skb, p->allocation);
898 } else {
899 p->skb2 = skb_get(p->skb);
900 /*
901 * skb ownership may have been set when
902 * delivered to a previous socket.
903 */
904 skb_orphan(p->skb2);
905 }
906 }
907 if (p->skb2 == NULL) {
908 netlink_overrun(sk);
909 /* Clone failed. Notify ALL listeners. */
910 p->failure = 1;
911 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
912 netlink_overrun(sk);
913 } else {
914 p->congested |= val;
915 p->delivered = 1;
916 p->skb2 = NULL;
917 }
918 sock_put(sk);
919
920 out:
921 return 0;
922 }
923
924 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
925 u32 group, gfp_t allocation)
926 {
927 struct netlink_broadcast_data info;
928 struct hlist_node *node;
929 struct sock *sk;
930
931 skb = netlink_trim(skb, allocation);
932
933 info.exclude_sk = ssk;
934 info.pid = pid;
935 info.group = group;
936 info.failure = 0;
937 info.congested = 0;
938 info.delivered = 0;
939 info.allocation = allocation;
940 info.skb = skb;
941 info.skb2 = NULL;
942
943 /* While we sleep in clone, do not allow to change socket list */
944
945 netlink_lock_table();
946
947 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
948 do_one_broadcast(sk, &info);
949
950 kfree_skb(skb);
951
952 netlink_unlock_table();
953
954 if (info.skb2)
955 kfree_skb(info.skb2);
956
957 if (info.delivered) {
958 if (info.congested && (allocation & __GFP_WAIT))
959 yield();
960 return 0;
961 }
962 if (info.failure)
963 return -ENOBUFS;
964 return -ESRCH;
965 }
966
967 struct netlink_set_err_data {
968 struct sock *exclude_sk;
969 u32 pid;
970 u32 group;
971 int code;
972 };
973
974 static inline int do_one_set_err(struct sock *sk,
975 struct netlink_set_err_data *p)
976 {
977 struct netlink_sock *nlk = nlk_sk(sk);
978
979 if (sk == p->exclude_sk)
980 goto out;
981
982 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
983 !test_bit(p->group - 1, nlk->groups))
984 goto out;
985
986 sk->sk_err = p->code;
987 sk->sk_error_report(sk);
988 out:
989 return 0;
990 }
991
992 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
993 {
994 struct netlink_set_err_data info;
995 struct hlist_node *node;
996 struct sock *sk;
997
998 info.exclude_sk = ssk;
999 info.pid = pid;
1000 info.group = group;
1001 info.code = code;
1002
1003 read_lock(&nl_table_lock);
1004
1005 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1006 do_one_set_err(sk, &info);
1007
1008 read_unlock(&nl_table_lock);
1009 }
1010
1011 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1012 char __user *optval, int optlen)
1013 {
1014 struct sock *sk = sock->sk;
1015 struct netlink_sock *nlk = nlk_sk(sk);
1016 int val = 0, err;
1017
1018 if (level != SOL_NETLINK)
1019 return -ENOPROTOOPT;
1020
1021 if (optlen >= sizeof(int) &&
1022 get_user(val, (int __user *)optval))
1023 return -EFAULT;
1024
1025 switch (optname) {
1026 case NETLINK_PKTINFO:
1027 if (val)
1028 nlk->flags |= NETLINK_RECV_PKTINFO;
1029 else
1030 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1031 err = 0;
1032 break;
1033 case NETLINK_ADD_MEMBERSHIP:
1034 case NETLINK_DROP_MEMBERSHIP: {
1035 unsigned int subscriptions;
1036 int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0;
1037
1038 if (!netlink_capable(sock, NL_NONROOT_RECV))
1039 return -EPERM;
1040 if (nlk->groups == NULL) {
1041 err = netlink_alloc_groups(sk);
1042 if (err)
1043 return err;
1044 }
1045 if (!val || val - 1 >= nlk->ngroups)
1046 return -EINVAL;
1047 netlink_table_grab();
1048 old = test_bit(val - 1, nlk->groups);
1049 subscriptions = nlk->subscriptions - old + new;
1050 if (new)
1051 __set_bit(val - 1, nlk->groups);
1052 else
1053 __clear_bit(val - 1, nlk->groups);
1054 netlink_update_subscriptions(sk, subscriptions);
1055 netlink_update_listeners(sk);
1056 netlink_table_ungrab();
1057 err = 0;
1058 break;
1059 }
1060 default:
1061 err = -ENOPROTOOPT;
1062 }
1063 return err;
1064 }
1065
1066 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1067 char __user *optval, int __user *optlen)
1068 {
1069 struct sock *sk = sock->sk;
1070 struct netlink_sock *nlk = nlk_sk(sk);
1071 int len, val, err;
1072
1073 if (level != SOL_NETLINK)
1074 return -ENOPROTOOPT;
1075
1076 if (get_user(len, optlen))
1077 return -EFAULT;
1078 if (len < 0)
1079 return -EINVAL;
1080
1081 switch (optname) {
1082 case NETLINK_PKTINFO:
1083 if (len < sizeof(int))
1084 return -EINVAL;
1085 len = sizeof(int);
1086 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1087 if (put_user(len, optlen) ||
1088 put_user(val, optval))
1089 return -EFAULT;
1090 err = 0;
1091 break;
1092 default:
1093 err = -ENOPROTOOPT;
1094 }
1095 return err;
1096 }
1097
1098 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1099 {
1100 struct nl_pktinfo info;
1101
1102 info.group = NETLINK_CB(skb).dst_group;
1103 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1104 }
1105
1106 static inline void netlink_rcv_wake(struct sock *sk)
1107 {
1108 struct netlink_sock *nlk = nlk_sk(sk);
1109
1110 if (skb_queue_empty(&sk->sk_receive_queue))
1111 clear_bit(0, &nlk->state);
1112 if (!test_bit(0, &nlk->state))
1113 wake_up_interruptible(&nlk->wait);
1114 }
1115
1116 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1117 struct msghdr *msg, size_t len)
1118 {
1119 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1120 struct sock *sk = sock->sk;
1121 struct netlink_sock *nlk = nlk_sk(sk);
1122 struct sockaddr_nl *addr=msg->msg_name;
1123 u32 dst_pid;
1124 u32 dst_group;
1125 struct sk_buff *skb;
1126 int err;
1127 struct scm_cookie scm;
1128
1129 if (msg->msg_flags&MSG_OOB)
1130 return -EOPNOTSUPP;
1131
1132 if (NULL == siocb->scm)
1133 siocb->scm = &scm;
1134 err = scm_send(sock, msg, siocb->scm);
1135 if (err < 0)
1136 return err;
1137
1138 if (msg->msg_namelen) {
1139 if (addr->nl_family != AF_NETLINK)
1140 return -EINVAL;
1141 dst_pid = addr->nl_pid;
1142 dst_group = ffs(addr->nl_groups);
1143 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1144 return -EPERM;
1145 } else {
1146 dst_pid = nlk->dst_pid;
1147 dst_group = nlk->dst_group;
1148 }
1149
1150 if (!nlk->pid) {
1151 err = netlink_autobind(sock);
1152 if (err)
1153 goto out;
1154 }
1155
1156 err = -EMSGSIZE;
1157 if (len > sk->sk_sndbuf - 32)
1158 goto out;
1159 err = -ENOBUFS;
1160 skb = alloc_skb(len, GFP_KERNEL);
1161 if (skb==NULL)
1162 goto out;
1163
1164 NETLINK_CB(skb).pid = nlk->pid;
1165 NETLINK_CB(skb).dst_group = dst_group;
1166 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
1167 selinux_get_task_sid(current, &(NETLINK_CB(skb).sid));
1168 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1169
1170 /* What can I do? Netlink is asynchronous, so that
1171 we will have to save current capabilities to
1172 check them, when this message will be delivered
1173 to corresponding kernel module. --ANK (980802)
1174 */
1175
1176 err = -EFAULT;
1177 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) {
1178 kfree_skb(skb);
1179 goto out;
1180 }
1181
1182 err = security_netlink_send(sk, skb);
1183 if (err) {
1184 kfree_skb(skb);
1185 goto out;
1186 }
1187
1188 if (dst_group) {
1189 atomic_inc(&skb->users);
1190 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1191 }
1192 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1193
1194 out:
1195 return err;
1196 }
1197
1198 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1199 struct msghdr *msg, size_t len,
1200 int flags)
1201 {
1202 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1203 struct scm_cookie scm;
1204 struct sock *sk = sock->sk;
1205 struct netlink_sock *nlk = nlk_sk(sk);
1206 int noblock = flags&MSG_DONTWAIT;
1207 size_t copied;
1208 struct sk_buff *skb;
1209 int err;
1210
1211 if (flags&MSG_OOB)
1212 return -EOPNOTSUPP;
1213
1214 copied = 0;
1215
1216 skb = skb_recv_datagram(sk,flags,noblock,&err);
1217 if (skb==NULL)
1218 goto out;
1219
1220 msg->msg_namelen = 0;
1221
1222 copied = skb->len;
1223 if (len < copied) {
1224 msg->msg_flags |= MSG_TRUNC;
1225 copied = len;
1226 }
1227
1228 skb_reset_transport_header(skb);
1229 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1230
1231 if (msg->msg_name) {
1232 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name;
1233 addr->nl_family = AF_NETLINK;
1234 addr->nl_pad = 0;
1235 addr->nl_pid = NETLINK_CB(skb).pid;
1236 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1237 msg->msg_namelen = sizeof(*addr);
1238 }
1239
1240 if (nlk->flags & NETLINK_RECV_PKTINFO)
1241 netlink_cmsg_recv_pktinfo(msg, skb);
1242
1243 if (NULL == siocb->scm) {
1244 memset(&scm, 0, sizeof(scm));
1245 siocb->scm = &scm;
1246 }
1247 siocb->scm->creds = *NETLINK_CREDS(skb);
1248 if (flags & MSG_TRUNC)
1249 copied = skb->len;
1250 skb_free_datagram(sk, skb);
1251
1252 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1253 netlink_dump(sk);
1254
1255 scm_recv(sock, msg, siocb->scm, flags);
1256 out:
1257 netlink_rcv_wake(sk);
1258 return err ? : copied;
1259 }
1260
1261 static void netlink_data_ready(struct sock *sk, int len)
1262 {
1263 struct netlink_sock *nlk = nlk_sk(sk);
1264
1265 if (nlk->data_ready)
1266 nlk->data_ready(sk, len);
1267 netlink_rcv_wake(sk);
1268 }
1269
1270 /*
1271 * We export these functions to other modules. They provide a
1272 * complete set of kernel non-blocking support for message
1273 * queueing.
1274 */
1275
1276 struct sock *
1277 netlink_kernel_create(int unit, unsigned int groups,
1278 void (*input)(struct sock *sk, int len),
1279 struct mutex *cb_mutex, struct module *module)
1280 {
1281 struct socket *sock;
1282 struct sock *sk;
1283 struct netlink_sock *nlk;
1284 unsigned long *listeners = NULL;
1285
1286 BUG_ON(!nl_table);
1287
1288 if (unit<0 || unit>=MAX_LINKS)
1289 return NULL;
1290
1291 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1292 return NULL;
1293
1294 if (__netlink_create(sock, cb_mutex, unit) < 0)
1295 goto out_sock_release;
1296
1297 if (groups < 32)
1298 groups = 32;
1299
1300 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
1301 if (!listeners)
1302 goto out_sock_release;
1303
1304 sk = sock->sk;
1305 sk->sk_data_ready = netlink_data_ready;
1306 if (input)
1307 nlk_sk(sk)->data_ready = input;
1308
1309 if (netlink_insert(sk, 0))
1310 goto out_sock_release;
1311
1312 nlk = nlk_sk(sk);
1313 nlk->flags |= NETLINK_KERNEL_SOCKET;
1314
1315 netlink_table_grab();
1316 nl_table[unit].groups = groups;
1317 nl_table[unit].listeners = listeners;
1318 nl_table[unit].cb_mutex = cb_mutex;
1319 nl_table[unit].module = module;
1320 nl_table[unit].registered = 1;
1321 netlink_table_ungrab();
1322
1323 return sk;
1324
1325 out_sock_release:
1326 kfree(listeners);
1327 sock_release(sock);
1328 return NULL;
1329 }
1330
1331 void netlink_set_nonroot(int protocol, unsigned int flags)
1332 {
1333 if ((unsigned int)protocol < MAX_LINKS)
1334 nl_table[protocol].nl_nonroot = flags;
1335 }
1336
1337 static void netlink_destroy_callback(struct netlink_callback *cb)
1338 {
1339 if (cb->skb)
1340 kfree_skb(cb->skb);
1341 kfree(cb);
1342 }
1343
1344 /*
1345 * It looks a bit ugly.
1346 * It would be better to create kernel thread.
1347 */
1348
1349 static int netlink_dump(struct sock *sk)
1350 {
1351 struct netlink_sock *nlk = nlk_sk(sk);
1352 struct netlink_callback *cb;
1353 struct sk_buff *skb;
1354 struct nlmsghdr *nlh;
1355 int len, err = -ENOBUFS;
1356
1357 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1358 if (!skb)
1359 goto errout;
1360
1361 mutex_lock(nlk->cb_mutex);
1362
1363 cb = nlk->cb;
1364 if (cb == NULL) {
1365 err = -EINVAL;
1366 goto errout_skb;
1367 }
1368
1369 len = cb->dump(skb, cb);
1370
1371 if (len > 0) {
1372 mutex_unlock(nlk->cb_mutex);
1373 skb_queue_tail(&sk->sk_receive_queue, skb);
1374 sk->sk_data_ready(sk, len);
1375 return 0;
1376 }
1377
1378 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1379 if (!nlh)
1380 goto errout_skb;
1381
1382 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1383
1384 skb_queue_tail(&sk->sk_receive_queue, skb);
1385 sk->sk_data_ready(sk, skb->len);
1386
1387 if (cb->done)
1388 cb->done(cb);
1389 nlk->cb = NULL;
1390 mutex_unlock(nlk->cb_mutex);
1391
1392 netlink_destroy_callback(cb);
1393 return 0;
1394
1395 errout_skb:
1396 mutex_unlock(nlk->cb_mutex);
1397 kfree_skb(skb);
1398 errout:
1399 return err;
1400 }
1401
1402 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1403 struct nlmsghdr *nlh,
1404 int (*dump)(struct sk_buff *skb, struct netlink_callback*),
1405 int (*done)(struct netlink_callback*))
1406 {
1407 struct netlink_callback *cb;
1408 struct sock *sk;
1409 struct netlink_sock *nlk;
1410
1411 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1412 if (cb == NULL)
1413 return -ENOBUFS;
1414
1415 cb->dump = dump;
1416 cb->done = done;
1417 cb->nlh = nlh;
1418 atomic_inc(&skb->users);
1419 cb->skb = skb;
1420
1421 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid);
1422 if (sk == NULL) {
1423 netlink_destroy_callback(cb);
1424 return -ECONNREFUSED;
1425 }
1426 nlk = nlk_sk(sk);
1427 /* A dump is in progress... */
1428 mutex_lock(nlk->cb_mutex);
1429 if (nlk->cb) {
1430 mutex_unlock(nlk->cb_mutex);
1431 netlink_destroy_callback(cb);
1432 sock_put(sk);
1433 return -EBUSY;
1434 }
1435 nlk->cb = cb;
1436 mutex_unlock(nlk->cb_mutex);
1437
1438 netlink_dump(sk);
1439 sock_put(sk);
1440
1441 /* We successfully started a dump, by returning -EINTR we
1442 * signal the queue mangement to interrupt processing of
1443 * any netlink messages so userspace gets a chance to read
1444 * the results. */
1445 return -EINTR;
1446 }
1447
1448 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1449 {
1450 struct sk_buff *skb;
1451 struct nlmsghdr *rep;
1452 struct nlmsgerr *errmsg;
1453 size_t payload = sizeof(*errmsg);
1454
1455 /* error messages get the original request appened */
1456 if (err)
1457 payload += nlmsg_len(nlh);
1458
1459 skb = nlmsg_new(payload, GFP_KERNEL);
1460 if (!skb) {
1461 struct sock *sk;
1462
1463 sk = netlink_lookup(in_skb->sk->sk_protocol,
1464 NETLINK_CB(in_skb).pid);
1465 if (sk) {
1466 sk->sk_err = ENOBUFS;
1467 sk->sk_error_report(sk);
1468 sock_put(sk);
1469 }
1470 return;
1471 }
1472
1473 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1474 NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
1475 errmsg = nlmsg_data(rep);
1476 errmsg->error = err;
1477 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1478 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1479 }
1480
1481 static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1482 struct nlmsghdr *))
1483 {
1484 struct nlmsghdr *nlh;
1485 int err;
1486
1487 while (skb->len >= nlmsg_total_size(0)) {
1488 nlh = nlmsg_hdr(skb);
1489 err = 0;
1490
1491 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1492 return 0;
1493
1494 /* Only requests are handled by the kernel */
1495 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1496 goto skip;
1497
1498 /* Skip control messages */
1499 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1500 goto skip;
1501
1502 err = cb(skb, nlh);
1503 if (err == -EINTR) {
1504 /* Not an error, but we interrupt processing */
1505 netlink_queue_skip(nlh, skb);
1506 return err;
1507 }
1508 skip:
1509 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1510 netlink_ack(skb, nlh, err);
1511
1512 netlink_queue_skip(nlh, skb);
1513 }
1514
1515 return 0;
1516 }
1517
1518 /**
1519 * nelink_run_queue - Process netlink receive queue.
1520 * @sk: Netlink socket containing the queue
1521 * @qlen: Place to store queue length upon entry
1522 * @cb: Callback function invoked for each netlink message found
1523 *
1524 * Processes as much as there was in the queue upon entry and invokes
1525 * a callback function for each netlink message found. The callback
1526 * function may refuse a message by returning a negative error code
1527 * but setting the error pointer to 0 in which case this function
1528 * returns with a qlen != 0.
1529 *
1530 * qlen must be initialized to 0 before the initial entry, afterwards
1531 * the function may be called repeatedly until qlen reaches 0.
1532 *
1533 * The callback function may return -EINTR to signal that processing
1534 * of netlink messages shall be interrupted. In this case the message
1535 * currently being processed will NOT be requeued onto the receive
1536 * queue.
1537 */
1538 void netlink_run_queue(struct sock *sk, unsigned int *qlen,
1539 int (*cb)(struct sk_buff *, struct nlmsghdr *))
1540 {
1541 struct sk_buff *skb;
1542
1543 if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue))
1544 *qlen = skb_queue_len(&sk->sk_receive_queue);
1545
1546 for (; *qlen; (*qlen)--) {
1547 skb = skb_dequeue(&sk->sk_receive_queue);
1548 if (netlink_rcv_skb(skb, cb)) {
1549 if (skb->len)
1550 skb_queue_head(&sk->sk_receive_queue, skb);
1551 else {
1552 kfree_skb(skb);
1553 (*qlen)--;
1554 }
1555 break;
1556 }
1557
1558 kfree_skb(skb);
1559 }
1560 }
1561
1562 /**
1563 * netlink_queue_skip - Skip netlink message while processing queue.
1564 * @nlh: Netlink message to be skipped
1565 * @skb: Socket buffer containing the netlink messages.
1566 *
1567 * Pulls the given netlink message off the socket buffer so the next
1568 * call to netlink_queue_run() will not reconsider the message.
1569 */
1570 static void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb)
1571 {
1572 int msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1573
1574 if (msglen > skb->len)
1575 msglen = skb->len;
1576
1577 skb_pull(skb, msglen);
1578 }
1579
1580 /**
1581 * nlmsg_notify - send a notification netlink message
1582 * @sk: netlink socket to use
1583 * @skb: notification message
1584 * @pid: destination netlink pid for reports or 0
1585 * @group: destination multicast group or 0
1586 * @report: 1 to report back, 0 to disable
1587 * @flags: allocation flags
1588 */
1589 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1590 unsigned int group, int report, gfp_t flags)
1591 {
1592 int err = 0;
1593
1594 if (group) {
1595 int exclude_pid = 0;
1596
1597 if (report) {
1598 atomic_inc(&skb->users);
1599 exclude_pid = pid;
1600 }
1601
1602 /* errors reported via destination sk->sk_err */
1603 nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1604 }
1605
1606 if (report)
1607 err = nlmsg_unicast(sk, skb, pid);
1608
1609 return err;
1610 }
1611
1612 #ifdef CONFIG_PROC_FS
1613 struct nl_seq_iter {
1614 int link;
1615 int hash_idx;
1616 };
1617
1618 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1619 {
1620 struct nl_seq_iter *iter = seq->private;
1621 int i, j;
1622 struct sock *s;
1623 struct hlist_node *node;
1624 loff_t off = 0;
1625
1626 for (i=0; i<MAX_LINKS; i++) {
1627 struct nl_pid_hash *hash = &nl_table[i].hash;
1628
1629 for (j = 0; j <= hash->mask; j++) {
1630 sk_for_each(s, node, &hash->table[j]) {
1631 if (off == pos) {
1632 iter->link = i;
1633 iter->hash_idx = j;
1634 return s;
1635 }
1636 ++off;
1637 }
1638 }
1639 }
1640 return NULL;
1641 }
1642
1643 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1644 {
1645 read_lock(&nl_table_lock);
1646 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1647 }
1648
1649 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1650 {
1651 struct sock *s;
1652 struct nl_seq_iter *iter;
1653 int i, j;
1654
1655 ++*pos;
1656
1657 if (v == SEQ_START_TOKEN)
1658 return netlink_seq_socket_idx(seq, 0);
1659
1660 s = sk_next(v);
1661 if (s)
1662 return s;
1663
1664 iter = seq->private;
1665 i = iter->link;
1666 j = iter->hash_idx + 1;
1667
1668 do {
1669 struct nl_pid_hash *hash = &nl_table[i].hash;
1670
1671 for (; j <= hash->mask; j++) {
1672 s = sk_head(&hash->table[j]);
1673 if (s) {
1674 iter->link = i;
1675 iter->hash_idx = j;
1676 return s;
1677 }
1678 }
1679
1680 j = 0;
1681 } while (++i < MAX_LINKS);
1682
1683 return NULL;
1684 }
1685
1686 static void netlink_seq_stop(struct seq_file *seq, void *v)
1687 {
1688 read_unlock(&nl_table_lock);
1689 }
1690
1691
1692 static int netlink_seq_show(struct seq_file *seq, void *v)
1693 {
1694 if (v == SEQ_START_TOKEN)
1695 seq_puts(seq,
1696 "sk Eth Pid Groups "
1697 "Rmem Wmem Dump Locks\n");
1698 else {
1699 struct sock *s = v;
1700 struct netlink_sock *nlk = nlk_sk(s);
1701
1702 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
1703 s,
1704 s->sk_protocol,
1705 nlk->pid,
1706 nlk->groups ? (u32)nlk->groups[0] : 0,
1707 atomic_read(&s->sk_rmem_alloc),
1708 atomic_read(&s->sk_wmem_alloc),
1709 nlk->cb,
1710 atomic_read(&s->sk_refcnt)
1711 );
1712
1713 }
1714 return 0;
1715 }
1716
1717 static struct seq_operations netlink_seq_ops = {
1718 .start = netlink_seq_start,
1719 .next = netlink_seq_next,
1720 .stop = netlink_seq_stop,
1721 .show = netlink_seq_show,
1722 };
1723
1724
1725 static int netlink_seq_open(struct inode *inode, struct file *file)
1726 {
1727 struct seq_file *seq;
1728 struct nl_seq_iter *iter;
1729 int err;
1730
1731 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1732 if (!iter)
1733 return -ENOMEM;
1734
1735 err = seq_open(file, &netlink_seq_ops);
1736 if (err) {
1737 kfree(iter);
1738 return err;
1739 }
1740
1741 seq = file->private_data;
1742 seq->private = iter;
1743 return 0;
1744 }
1745
1746 static const struct file_operations netlink_seq_fops = {
1747 .owner = THIS_MODULE,
1748 .open = netlink_seq_open,
1749 .read = seq_read,
1750 .llseek = seq_lseek,
1751 .release = seq_release_private,
1752 };
1753
1754 #endif
1755
1756 int netlink_register_notifier(struct notifier_block *nb)
1757 {
1758 return atomic_notifier_chain_register(&netlink_chain, nb);
1759 }
1760
1761 int netlink_unregister_notifier(struct notifier_block *nb)
1762 {
1763 return atomic_notifier_chain_unregister(&netlink_chain, nb);
1764 }
1765
1766 static const struct proto_ops netlink_ops = {
1767 .family = PF_NETLINK,
1768 .owner = THIS_MODULE,
1769 .release = netlink_release,
1770 .bind = netlink_bind,
1771 .connect = netlink_connect,
1772 .socketpair = sock_no_socketpair,
1773 .accept = sock_no_accept,
1774 .getname = netlink_getname,
1775 .poll = datagram_poll,
1776 .ioctl = sock_no_ioctl,
1777 .listen = sock_no_listen,
1778 .shutdown = sock_no_shutdown,
1779 .setsockopt = netlink_setsockopt,
1780 .getsockopt = netlink_getsockopt,
1781 .sendmsg = netlink_sendmsg,
1782 .recvmsg = netlink_recvmsg,
1783 .mmap = sock_no_mmap,
1784 .sendpage = sock_no_sendpage,
1785 };
1786
1787 static struct net_proto_family netlink_family_ops = {
1788 .family = PF_NETLINK,
1789 .create = netlink_create,
1790 .owner = THIS_MODULE, /* for consistency 8) */
1791 };
1792
1793 static int __init netlink_proto_init(void)
1794 {
1795 struct sk_buff *dummy_skb;
1796 int i;
1797 unsigned long max;
1798 unsigned int order;
1799 int err = proto_register(&netlink_proto, 0);
1800
1801 if (err != 0)
1802 goto out;
1803
1804 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
1805
1806 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
1807 if (!nl_table)
1808 goto panic;
1809
1810 if (num_physpages >= (128 * 1024))
1811 max = num_physpages >> (21 - PAGE_SHIFT);
1812 else
1813 max = num_physpages >> (23 - PAGE_SHIFT);
1814
1815 order = get_bitmask_order(max) - 1 + PAGE_SHIFT;
1816 max = (1UL << order) / sizeof(struct hlist_head);
1817 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1;
1818
1819 for (i = 0; i < MAX_LINKS; i++) {
1820 struct nl_pid_hash *hash = &nl_table[i].hash;
1821
1822 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table));
1823 if (!hash->table) {
1824 while (i-- > 0)
1825 nl_pid_hash_free(nl_table[i].hash.table,
1826 1 * sizeof(*hash->table));
1827 kfree(nl_table);
1828 goto panic;
1829 }
1830 memset(hash->table, 0, 1 * sizeof(*hash->table));
1831 hash->max_shift = order;
1832 hash->shift = 0;
1833 hash->mask = 0;
1834 hash->rehash_time = jiffies;
1835 }
1836
1837 sock_register(&netlink_family_ops);
1838 #ifdef CONFIG_PROC_FS
1839 proc_net_fops_create("netlink", 0, &netlink_seq_fops);
1840 #endif
1841 /* The netlink device handler may be needed early. */
1842 rtnetlink_init();
1843 out:
1844 return err;
1845 panic:
1846 panic("netlink_init: Cannot allocate nl_table\n");
1847 }
1848
1849 core_initcall(netlink_proto_init);
1850
1851 EXPORT_SYMBOL(netlink_ack);
1852 EXPORT_SYMBOL(netlink_run_queue);
1853 EXPORT_SYMBOL(netlink_broadcast);
1854 EXPORT_SYMBOL(netlink_dump_start);
1855 EXPORT_SYMBOL(netlink_kernel_create);
1856 EXPORT_SYMBOL(netlink_register_notifier);
1857 EXPORT_SYMBOL(netlink_set_nonroot);
1858 EXPORT_SYMBOL(netlink_unicast);
1859 EXPORT_SYMBOL(netlink_unregister_notifier);
1860 EXPORT_SYMBOL(nlmsg_notify);
CJK support for tty framebuffer vt