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[IA64-SGI] fix SGI Altix tioce_bus_fixup() bug
[zen-stable.git] / net / netlink / af_netlink.c
blob3862e73d14d731b1c3674d811412fe1b29eab6dc
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/config.h>
25 #include <linux/module.h>
26
27 #include <linux/capability.h>
28 #include <linux/kernel.h>
29 #include <linux/init.h>
30 #include <linux/signal.h>
31 #include <linux/sched.h>
32 #include <linux/errno.h>
33 #include <linux/string.h>
34 #include <linux/stat.h>
35 #include <linux/socket.h>
36 #include <linux/un.h>
37 #include <linux/fcntl.h>
38 #include <linux/termios.h>
39 #include <linux/sockios.h>
40 #include <linux/net.h>
41 #include <linux/fs.h>
42 #include <linux/slab.h>
43 #include <asm/uaccess.h>
44 #include <linux/skbuff.h>
45 #include <linux/netdevice.h>
46 #include <linux/rtnetlink.h>
47 #include <linux/proc_fs.h>
48 #include <linux/seq_file.h>
49 #include <linux/smp_lock.h>
50 #include <linux/notifier.h>
51 #include <linux/security.h>
52 #include <linux/jhash.h>
53 #include <linux/jiffies.h>
54 #include <linux/random.h>
55 #include <linux/bitops.h>
56 #include <linux/mm.h>
57 #include <linux/types.h>
58 #include <linux/audit.h>
59 #include <linux/selinux.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 spinlock_t cb_lock;
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 module *module;
113 int registered;
114 };
115
116 static struct netlink_table *nl_table;
117
118 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
119
120 static int netlink_dump(struct sock *sk);
121 static void netlink_destroy_callback(struct netlink_callback *cb);
122
123 static DEFINE_RWLOCK(nl_table_lock);
124 static atomic_t nl_table_users = ATOMIC_INIT(0);
125
126 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
127
128 static u32 netlink_group_mask(u32 group)
129 {
130 return group ? 1 << (group - 1) : 0;
131 }
132
133 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
134 {
135 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
136 }
137
138 static void netlink_sock_destruct(struct sock *sk)
139 {
140 skb_queue_purge(&sk->sk_receive_queue);
141
142 if (!sock_flag(sk, SOCK_DEAD)) {
143 printk("Freeing alive netlink socket %p\n", sk);
144 return;
145 }
146 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
147 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
148 BUG_TRAP(!nlk_sk(sk)->cb);
149 BUG_TRAP(!nlk_sk(sk)->groups);
150 }
151
152 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
153 * Look, when several writers sleep and reader wakes them up, all but one
154 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
155 * this, _but_ remember, it adds useless work on UP machines.
156 */
157
158 static void netlink_table_grab(void)
159 {
160 write_lock_bh(&nl_table_lock);
161
162 if (atomic_read(&nl_table_users)) {
163 DECLARE_WAITQUEUE(wait, current);
164
165 add_wait_queue_exclusive(&nl_table_wait, &wait);
166 for(;;) {
167 set_current_state(TASK_UNINTERRUPTIBLE);
168 if (atomic_read(&nl_table_users) == 0)
169 break;
170 write_unlock_bh(&nl_table_lock);
171 schedule();
172 write_lock_bh(&nl_table_lock);
173 }
174
175 __set_current_state(TASK_RUNNING);
176 remove_wait_queue(&nl_table_wait, &wait);
177 }
178 }
179
180 static __inline__ void netlink_table_ungrab(void)
181 {
182 write_unlock_bh(&nl_table_lock);
183 wake_up(&nl_table_wait);
184 }
185
186 static __inline__ void
187 netlink_lock_table(void)
188 {
189 /* read_lock() synchronizes us to netlink_table_grab */
190
191 read_lock(&nl_table_lock);
192 atomic_inc(&nl_table_users);
193 read_unlock(&nl_table_lock);
194 }
195
196 static __inline__ void
197 netlink_unlock_table(void)
198 {
199 if (atomic_dec_and_test(&nl_table_users))
200 wake_up(&nl_table_wait);
201 }
202
203 static __inline__ struct sock *netlink_lookup(int protocol, u32 pid)
204 {
205 struct nl_pid_hash *hash = &nl_table[protocol].hash;
206 struct hlist_head *head;
207 struct sock *sk;
208 struct hlist_node *node;
209
210 read_lock(&nl_table_lock);
211 head = nl_pid_hashfn(hash, pid);
212 sk_for_each(sk, node, head) {
213 if (nlk_sk(sk)->pid == pid) {
214 sock_hold(sk);
215 goto found;
216 }
217 }
218 sk = NULL;
219 found:
220 read_unlock(&nl_table_lock);
221 return sk;
222 }
223
224 static inline struct hlist_head *nl_pid_hash_alloc(size_t size)
225 {
226 if (size <= PAGE_SIZE)
227 return kmalloc(size, GFP_ATOMIC);
228 else
229 return (struct hlist_head *)
230 __get_free_pages(GFP_ATOMIC, get_order(size));
231 }
232
233 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
234 {
235 if (size <= PAGE_SIZE)
236 kfree(table);
237 else
238 free_pages((unsigned long)table, get_order(size));
239 }
240
241 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
242 {
243 unsigned int omask, mask, shift;
244 size_t osize, size;
245 struct hlist_head *otable, *table;
246 int i;
247
248 omask = mask = hash->mask;
249 osize = size = (mask + 1) * sizeof(*table);
250 shift = hash->shift;
251
252 if (grow) {
253 if (++shift > hash->max_shift)
254 return 0;
255 mask = mask * 2 + 1;
256 size *= 2;
257 }
258
259 table = nl_pid_hash_alloc(size);
260 if (!table)
261 return 0;
262
263 memset(table, 0, size);
264 otable = hash->table;
265 hash->table = table;
266 hash->mask = mask;
267 hash->shift = shift;
268 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
269
270 for (i = 0; i <= omask; i++) {
271 struct sock *sk;
272 struct hlist_node *node, *tmp;
273
274 sk_for_each_safe(sk, node, tmp, &otable[i])
275 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
276 }
277
278 nl_pid_hash_free(otable, osize);
279 hash->rehash_time = jiffies + 10 * 60 * HZ;
280 return 1;
281 }
282
283 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
284 {
285 int avg = hash->entries >> hash->shift;
286
287 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
288 return 1;
289
290 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
291 nl_pid_hash_rehash(hash, 0);
292 return 1;
293 }
294
295 return 0;
296 }
297
298 static const struct proto_ops netlink_ops;
299
300 static void
301 netlink_update_listeners(struct sock *sk)
302 {
303 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
304 struct hlist_node *node;
305 unsigned long mask;
306 unsigned int i;
307
308 for (i = 0; i < NLGRPSZ(tbl->groups)/sizeof(unsigned long); i++) {
309 mask = 0;
310 sk_for_each_bound(sk, node, &tbl->mc_list)
311 mask |= nlk_sk(sk)->groups[i];
312 tbl->listeners[i] = mask;
313 }
314 /* this function is only called with the netlink table "grabbed", which
315 * makes sure updates are visible before bind or setsockopt return. */
316 }
317
318 static int netlink_insert(struct sock *sk, u32 pid)
319 {
320 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
321 struct hlist_head *head;
322 int err = -EADDRINUSE;
323 struct sock *osk;
324 struct hlist_node *node;
325 int len;
326
327 netlink_table_grab();
328 head = nl_pid_hashfn(hash, pid);
329 len = 0;
330 sk_for_each(osk, node, head) {
331 if (nlk_sk(osk)->pid == pid)
332 break;
333 len++;
334 }
335 if (node)
336 goto err;
337
338 err = -EBUSY;
339 if (nlk_sk(sk)->pid)
340 goto err;
341
342 err = -ENOMEM;
343 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
344 goto err;
345
346 if (len && nl_pid_hash_dilute(hash, len))
347 head = nl_pid_hashfn(hash, pid);
348 hash->entries++;
349 nlk_sk(sk)->pid = pid;
350 sk_add_node(sk, head);
351 err = 0;
352
353 err:
354 netlink_table_ungrab();
355 return err;
356 }
357
358 static void netlink_remove(struct sock *sk)
359 {
360 netlink_table_grab();
361 if (sk_del_node_init(sk))
362 nl_table[sk->sk_protocol].hash.entries--;
363 if (nlk_sk(sk)->subscriptions)
364 __sk_del_bind_node(sk);
365 netlink_table_ungrab();
366 }
367
368 static struct proto netlink_proto = {
369 .name = "NETLINK",
370 .owner = THIS_MODULE,
371 .obj_size = sizeof(struct netlink_sock),
372 };
373
374 static int __netlink_create(struct socket *sock, int protocol)
375 {
376 struct sock *sk;
377 struct netlink_sock *nlk;
378
379 sock->ops = &netlink_ops;
380
381 sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
382 if (!sk)
383 return -ENOMEM;
384
385 sock_init_data(sock, sk);
386
387 nlk = nlk_sk(sk);
388 spin_lock_init(&nlk->cb_lock);
389 init_waitqueue_head(&nlk->wait);
390
391 sk->sk_destruct = netlink_sock_destruct;
392 sk->sk_protocol = protocol;
393 return 0;
394 }
395
396 static int netlink_create(struct socket *sock, int protocol)
397 {
398 struct module *module = NULL;
399 struct netlink_sock *nlk;
400 unsigned int groups;
401 int err = 0;
402
403 sock->state = SS_UNCONNECTED;
404
405 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
406 return -ESOCKTNOSUPPORT;
407
408 if (protocol<0 || protocol >= MAX_LINKS)
409 return -EPROTONOSUPPORT;
410
411 netlink_lock_table();
412 #ifdef CONFIG_KMOD
413 if (!nl_table[protocol].registered) {
414 netlink_unlock_table();
415 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
416 netlink_lock_table();
417 }
418 #endif
419 if (nl_table[protocol].registered &&
420 try_module_get(nl_table[protocol].module))
421 module = nl_table[protocol].module;
422 groups = nl_table[protocol].groups;
423 netlink_unlock_table();
424
425 if ((err = __netlink_create(sock, protocol)) < 0)
426 goto out_module;
427
428 nlk = nlk_sk(sock->sk);
429 nlk->module = module;
430 out:
431 return err;
432
433 out_module:
434 module_put(module);
435 goto out;
436 }
437
438 static int netlink_release(struct socket *sock)
439 {
440 struct sock *sk = sock->sk;
441 struct netlink_sock *nlk;
442
443 if (!sk)
444 return 0;
445
446 netlink_remove(sk);
447 nlk = nlk_sk(sk);
448
449 spin_lock(&nlk->cb_lock);
450 if (nlk->cb) {
451 if (nlk->cb->done)
452 nlk->cb->done(nlk->cb);
453 netlink_destroy_callback(nlk->cb);
454 nlk->cb = NULL;
455 }
456 spin_unlock(&nlk->cb_lock);
457
458 /* OK. Socket is unlinked, and, therefore,
459 no new packets will arrive */
460
461 sock_orphan(sk);
462 sock->sk = NULL;
463 wake_up_interruptible_all(&nlk->wait);
464
465 skb_queue_purge(&sk->sk_write_queue);
466
467 if (nlk->pid && !nlk->subscriptions) {
468 struct netlink_notify n = {
469 .protocol = sk->sk_protocol,
470 .pid = nlk->pid,
471 };
472 atomic_notifier_call_chain(&netlink_chain,
473 NETLINK_URELEASE, &n);
474 }
475
476 if (nlk->module)
477 module_put(nlk->module);
478
479 netlink_table_grab();
480 if (nlk->flags & NETLINK_KERNEL_SOCKET) {
481 kfree(nl_table[sk->sk_protocol].listeners);
482 nl_table[sk->sk_protocol].module = NULL;
483 nl_table[sk->sk_protocol].registered = 0;
484 } else if (nlk->subscriptions)
485 netlink_update_listeners(sk);
486 netlink_table_ungrab();
487
488 kfree(nlk->groups);
489 nlk->groups = NULL;
490
491 sock_put(sk);
492 return 0;
493 }
494
495 static int netlink_autobind(struct socket *sock)
496 {
497 struct sock *sk = sock->sk;
498 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
499 struct hlist_head *head;
500 struct sock *osk;
501 struct hlist_node *node;
502 s32 pid = current->tgid;
503 int err;
504 static s32 rover = -4097;
505
506 retry:
507 cond_resched();
508 netlink_table_grab();
509 head = nl_pid_hashfn(hash, pid);
510 sk_for_each(osk, node, head) {
511 if (nlk_sk(osk)->pid == pid) {
512 /* Bind collision, search negative pid values. */
513 pid = rover--;
514 if (rover > -4097)
515 rover = -4097;
516 netlink_table_ungrab();
517 goto retry;
518 }
519 }
520 netlink_table_ungrab();
521
522 err = netlink_insert(sk, pid);
523 if (err == -EADDRINUSE)
524 goto retry;
525
526 /* If 2 threads race to autobind, that is fine. */
527 if (err == -EBUSY)
528 err = 0;
529
530 return err;
531 }
532
533 static inline int netlink_capable(struct socket *sock, unsigned int flag)
534 {
535 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
536 capable(CAP_NET_ADMIN);
537 }
538
539 static void
540 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
541 {
542 struct netlink_sock *nlk = nlk_sk(sk);
543
544 if (nlk->subscriptions && !subscriptions)
545 __sk_del_bind_node(sk);
546 else if (!nlk->subscriptions && subscriptions)
547 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
548 nlk->subscriptions = subscriptions;
549 }
550
551 static int netlink_alloc_groups(struct sock *sk)
552 {
553 struct netlink_sock *nlk = nlk_sk(sk);
554 unsigned int groups;
555 int err = 0;
556
557 netlink_lock_table();
558 groups = nl_table[sk->sk_protocol].groups;
559 if (!nl_table[sk->sk_protocol].registered)
560 err = -ENOENT;
561 netlink_unlock_table();
562
563 if (err)
564 return err;
565
566 nlk->groups = kmalloc(NLGRPSZ(groups), GFP_KERNEL);
567 if (nlk->groups == NULL)
568 return -ENOMEM;
569 memset(nlk->groups, 0, NLGRPSZ(groups));
570 nlk->ngroups = groups;
571 return 0;
572 }
573
574 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
575 {
576 struct sock *sk = sock->sk;
577 struct netlink_sock *nlk = nlk_sk(sk);
578 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
579 int err;
580
581 if (nladdr->nl_family != AF_NETLINK)
582 return -EINVAL;
583
584 /* Only superuser is allowed to listen multicasts */
585 if (nladdr->nl_groups) {
586 if (!netlink_capable(sock, NL_NONROOT_RECV))
587 return -EPERM;
588 if (nlk->groups == NULL) {
589 err = netlink_alloc_groups(sk);
590 if (err)
591 return err;
592 }
593 }
594
595 if (nlk->pid) {
596 if (nladdr->nl_pid != nlk->pid)
597 return -EINVAL;
598 } else {
599 err = nladdr->nl_pid ?
600 netlink_insert(sk, nladdr->nl_pid) :
601 netlink_autobind(sock);
602 if (err)
603 return err;
604 }
605
606 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
607 return 0;
608
609 netlink_table_grab();
610 netlink_update_subscriptions(sk, nlk->subscriptions +
611 hweight32(nladdr->nl_groups) -
612 hweight32(nlk->groups[0]));
613 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
614 netlink_update_listeners(sk);
615 netlink_table_ungrab();
616
617 return 0;
618 }
619
620 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
621 int alen, int flags)
622 {
623 int err = 0;
624 struct sock *sk = sock->sk;
625 struct netlink_sock *nlk = nlk_sk(sk);
626 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr;
627
628 if (addr->sa_family == AF_UNSPEC) {
629 sk->sk_state = NETLINK_UNCONNECTED;
630 nlk->dst_pid = 0;
631 nlk->dst_group = 0;
632 return 0;
633 }
634 if (addr->sa_family != AF_NETLINK)
635 return -EINVAL;
636
637 /* Only superuser is allowed to send multicasts */
638 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
639 return -EPERM;
640
641 if (!nlk->pid)
642 err = netlink_autobind(sock);
643
644 if (err == 0) {
645 sk->sk_state = NETLINK_CONNECTED;
646 nlk->dst_pid = nladdr->nl_pid;
647 nlk->dst_group = ffs(nladdr->nl_groups);
648 }
649
650 return err;
651 }
652
653 static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer)
654 {
655 struct sock *sk = sock->sk;
656 struct netlink_sock *nlk = nlk_sk(sk);
657 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr;
658
659 nladdr->nl_family = AF_NETLINK;
660 nladdr->nl_pad = 0;
661 *addr_len = sizeof(*nladdr);
662
663 if (peer) {
664 nladdr->nl_pid = nlk->dst_pid;
665 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
666 } else {
667 nladdr->nl_pid = nlk->pid;
668 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
669 }
670 return 0;
671 }
672
673 static void netlink_overrun(struct sock *sk)
674 {
675 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
676 sk->sk_err = ENOBUFS;
677 sk->sk_error_report(sk);
678 }
679 }
680
681 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
682 {
683 int protocol = ssk->sk_protocol;
684 struct sock *sock;
685 struct netlink_sock *nlk;
686
687 sock = netlink_lookup(protocol, pid);
688 if (!sock)
689 return ERR_PTR(-ECONNREFUSED);
690
691 /* Don't bother queuing skb if kernel socket has no input function */
692 nlk = nlk_sk(sock);
693 if ((nlk->pid == 0 && !nlk->data_ready) ||
694 (sock->sk_state == NETLINK_CONNECTED &&
695 nlk->dst_pid != nlk_sk(ssk)->pid)) {
696 sock_put(sock);
697 return ERR_PTR(-ECONNREFUSED);
698 }
699 return sock;
700 }
701
702 struct sock *netlink_getsockbyfilp(struct file *filp)
703 {
704 struct inode *inode = filp->f_dentry->d_inode;
705 struct sock *sock;
706
707 if (!S_ISSOCK(inode->i_mode))
708 return ERR_PTR(-ENOTSOCK);
709
710 sock = SOCKET_I(inode)->sk;
711 if (sock->sk_family != AF_NETLINK)
712 return ERR_PTR(-EINVAL);
713
714 sock_hold(sock);
715 return sock;
716 }
717
718 /*
719 * Attach a skb to a netlink socket.
720 * The caller must hold a reference to the destination socket. On error, the
721 * reference is dropped. The skb is not send to the destination, just all
722 * all error checks are performed and memory in the queue is reserved.
723 * Return values:
724 * < 0: error. skb freed, reference to sock dropped.
725 * 0: continue
726 * 1: repeat lookup - reference dropped while waiting for socket memory.
727 */
728 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock,
729 long timeo, struct sock *ssk)
730 {
731 struct netlink_sock *nlk;
732
733 nlk = nlk_sk(sk);
734
735 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
736 test_bit(0, &nlk->state)) {
737 DECLARE_WAITQUEUE(wait, current);
738 if (!timeo) {
739 if (!ssk || nlk_sk(ssk)->pid == 0)
740 netlink_overrun(sk);
741 sock_put(sk);
742 kfree_skb(skb);
743 return -EAGAIN;
744 }
745
746 __set_current_state(TASK_INTERRUPTIBLE);
747 add_wait_queue(&nlk->wait, &wait);
748
749 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
750 test_bit(0, &nlk->state)) &&
751 !sock_flag(sk, SOCK_DEAD))
752 timeo = schedule_timeout(timeo);
753
754 __set_current_state(TASK_RUNNING);
755 remove_wait_queue(&nlk->wait, &wait);
756 sock_put(sk);
757
758 if (signal_pending(current)) {
759 kfree_skb(skb);
760 return sock_intr_errno(timeo);
761 }
762 return 1;
763 }
764 skb_set_owner_r(skb, sk);
765 return 0;
766 }
767
768 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol)
769 {
770 int len = skb->len;
771
772 skb_queue_tail(&sk->sk_receive_queue, skb);
773 sk->sk_data_ready(sk, len);
774 sock_put(sk);
775 return len;
776 }
777
778 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
779 {
780 kfree_skb(skb);
781 sock_put(sk);
782 }
783
784 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
785 gfp_t allocation)
786 {
787 int delta;
788
789 skb_orphan(skb);
790
791 delta = skb->end - skb->tail;
792 if (delta * 2 < skb->truesize)
793 return skb;
794
795 if (skb_shared(skb)) {
796 struct sk_buff *nskb = skb_clone(skb, allocation);
797 if (!nskb)
798 return skb;
799 kfree_skb(skb);
800 skb = nskb;
801 }
802
803 if (!pskb_expand_head(skb, 0, -delta, allocation))
804 skb->truesize -= delta;
805
806 return skb;
807 }
808
809 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock)
810 {
811 struct sock *sk;
812 int err;
813 long timeo;
814
815 skb = netlink_trim(skb, gfp_any());
816
817 timeo = sock_sndtimeo(ssk, nonblock);
818 retry:
819 sk = netlink_getsockbypid(ssk, pid);
820 if (IS_ERR(sk)) {
821 kfree_skb(skb);
822 return PTR_ERR(sk);
823 }
824 err = netlink_attachskb(sk, skb, nonblock, timeo, ssk);
825 if (err == 1)
826 goto retry;
827 if (err)
828 return err;
829
830 return netlink_sendskb(sk, skb, ssk->sk_protocol);
831 }
832
833 int netlink_has_listeners(struct sock *sk, unsigned int group)
834 {
835 int res = 0;
836
837 BUG_ON(!(nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET));
838 if (group - 1 < nl_table[sk->sk_protocol].groups)
839 res = test_bit(group - 1, nl_table[sk->sk_protocol].listeners);
840 return res;
841 }
842 EXPORT_SYMBOL_GPL(netlink_has_listeners);
843
844 static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
845 {
846 struct netlink_sock *nlk = nlk_sk(sk);
847
848 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
849 !test_bit(0, &nlk->state)) {
850 skb_set_owner_r(skb, sk);
851 skb_queue_tail(&sk->sk_receive_queue, skb);
852 sk->sk_data_ready(sk, skb->len);
853 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
854 }
855 return -1;
856 }
857
858 struct netlink_broadcast_data {
859 struct sock *exclude_sk;
860 u32 pid;
861 u32 group;
862 int failure;
863 int congested;
864 int delivered;
865 gfp_t allocation;
866 struct sk_buff *skb, *skb2;
867 };
868
869 static inline int do_one_broadcast(struct sock *sk,
870 struct netlink_broadcast_data *p)
871 {
872 struct netlink_sock *nlk = nlk_sk(sk);
873 int val;
874
875 if (p->exclude_sk == sk)
876 goto out;
877
878 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
879 !test_bit(p->group - 1, nlk->groups))
880 goto out;
881
882 if (p->failure) {
883 netlink_overrun(sk);
884 goto out;
885 }
886
887 sock_hold(sk);
888 if (p->skb2 == NULL) {
889 if (skb_shared(p->skb)) {
890 p->skb2 = skb_clone(p->skb, p->allocation);
891 } else {
892 p->skb2 = skb_get(p->skb);
893 /*
894 * skb ownership may have been set when
895 * delivered to a previous socket.
896 */
897 skb_orphan(p->skb2);
898 }
899 }
900 if (p->skb2 == NULL) {
901 netlink_overrun(sk);
902 /* Clone failed. Notify ALL listeners. */
903 p->failure = 1;
904 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
905 netlink_overrun(sk);
906 } else {
907 p->congested |= val;
908 p->delivered = 1;
909 p->skb2 = NULL;
910 }
911 sock_put(sk);
912
913 out:
914 return 0;
915 }
916
917 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
918 u32 group, gfp_t allocation)
919 {
920 struct netlink_broadcast_data info;
921 struct hlist_node *node;
922 struct sock *sk;
923
924 skb = netlink_trim(skb, allocation);
925
926 info.exclude_sk = ssk;
927 info.pid = pid;
928 info.group = group;
929 info.failure = 0;
930 info.congested = 0;
931 info.delivered = 0;
932 info.allocation = allocation;
933 info.skb = skb;
934 info.skb2 = NULL;
935
936 /* While we sleep in clone, do not allow to change socket list */
937
938 netlink_lock_table();
939
940 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
941 do_one_broadcast(sk, &info);
942
943 kfree_skb(skb);
944
945 netlink_unlock_table();
946
947 if (info.skb2)
948 kfree_skb(info.skb2);
949
950 if (info.delivered) {
951 if (info.congested && (allocation & __GFP_WAIT))
952 yield();
953 return 0;
954 }
955 if (info.failure)
956 return -ENOBUFS;
957 return -ESRCH;
958 }
959
960 struct netlink_set_err_data {
961 struct sock *exclude_sk;
962 u32 pid;
963 u32 group;
964 int code;
965 };
966
967 static inline int do_one_set_err(struct sock *sk,
968 struct netlink_set_err_data *p)
969 {
970 struct netlink_sock *nlk = nlk_sk(sk);
971
972 if (sk == p->exclude_sk)
973 goto out;
974
975 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
976 !test_bit(p->group - 1, nlk->groups))
977 goto out;
978
979 sk->sk_err = p->code;
980 sk->sk_error_report(sk);
981 out:
982 return 0;
983 }
984
985 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
986 {
987 struct netlink_set_err_data info;
988 struct hlist_node *node;
989 struct sock *sk;
990
991 info.exclude_sk = ssk;
992 info.pid = pid;
993 info.group = group;
994 info.code = code;
995
996 read_lock(&nl_table_lock);
997
998 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
999 do_one_set_err(sk, &info);
1000
1001 read_unlock(&nl_table_lock);
1002 }
1003
1004 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1005 char __user *optval, int optlen)
1006 {
1007 struct sock *sk = sock->sk;
1008 struct netlink_sock *nlk = nlk_sk(sk);
1009 int val = 0, err;
1010
1011 if (level != SOL_NETLINK)
1012 return -ENOPROTOOPT;
1013
1014 if (optlen >= sizeof(int) &&
1015 get_user(val, (int __user *)optval))
1016 return -EFAULT;
1017
1018 switch (optname) {
1019 case NETLINK_PKTINFO:
1020 if (val)
1021 nlk->flags |= NETLINK_RECV_PKTINFO;
1022 else
1023 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1024 err = 0;
1025 break;
1026 case NETLINK_ADD_MEMBERSHIP:
1027 case NETLINK_DROP_MEMBERSHIP: {
1028 unsigned int subscriptions;
1029 int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0;
1030
1031 if (!netlink_capable(sock, NL_NONROOT_RECV))
1032 return -EPERM;
1033 if (nlk->groups == NULL) {
1034 err = netlink_alloc_groups(sk);
1035 if (err)
1036 return err;
1037 }
1038 if (!val || val - 1 >= nlk->ngroups)
1039 return -EINVAL;
1040 netlink_table_grab();
1041 old = test_bit(val - 1, nlk->groups);
1042 subscriptions = nlk->subscriptions - old + new;
1043 if (new)
1044 __set_bit(val - 1, nlk->groups);
1045 else
1046 __clear_bit(val - 1, nlk->groups);
1047 netlink_update_subscriptions(sk, subscriptions);
1048 netlink_update_listeners(sk);
1049 netlink_table_ungrab();
1050 err = 0;
1051 break;
1052 }
1053 default:
1054 err = -ENOPROTOOPT;
1055 }
1056 return err;
1057 }
1058
1059 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1060 char __user *optval, int __user *optlen)
1061 {
1062 struct sock *sk = sock->sk;
1063 struct netlink_sock *nlk = nlk_sk(sk);
1064 int len, val, err;
1065
1066 if (level != SOL_NETLINK)
1067 return -ENOPROTOOPT;
1068
1069 if (get_user(len, optlen))
1070 return -EFAULT;
1071 if (len < 0)
1072 return -EINVAL;
1073
1074 switch (optname) {
1075 case NETLINK_PKTINFO:
1076 if (len < sizeof(int))
1077 return -EINVAL;
1078 len = sizeof(int);
1079 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1080 put_user(len, optlen);
1081 put_user(val, optval);
1082 err = 0;
1083 break;
1084 default:
1085 err = -ENOPROTOOPT;
1086 }
1087 return err;
1088 }
1089
1090 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1091 {
1092 struct nl_pktinfo info;
1093
1094 info.group = NETLINK_CB(skb).dst_group;
1095 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1096 }
1097
1098 static inline void netlink_rcv_wake(struct sock *sk)
1099 {
1100 struct netlink_sock *nlk = nlk_sk(sk);
1101
1102 if (skb_queue_empty(&sk->sk_receive_queue))
1103 clear_bit(0, &nlk->state);
1104 if (!test_bit(0, &nlk->state))
1105 wake_up_interruptible(&nlk->wait);
1106 }
1107
1108 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1109 struct msghdr *msg, size_t len)
1110 {
1111 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1112 struct sock *sk = sock->sk;
1113 struct netlink_sock *nlk = nlk_sk(sk);
1114 struct sockaddr_nl *addr=msg->msg_name;
1115 u32 dst_pid;
1116 u32 dst_group;
1117 struct sk_buff *skb;
1118 int err;
1119 struct scm_cookie scm;
1120
1121 if (msg->msg_flags&MSG_OOB)
1122 return -EOPNOTSUPP;
1123
1124 if (NULL == siocb->scm)
1125 siocb->scm = &scm;
1126 err = scm_send(sock, msg, siocb->scm);
1127 if (err < 0)
1128 return err;
1129
1130 if (msg->msg_namelen) {
1131 if (addr->nl_family != AF_NETLINK)
1132 return -EINVAL;
1133 dst_pid = addr->nl_pid;
1134 dst_group = ffs(addr->nl_groups);
1135 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1136 return -EPERM;
1137 } else {
1138 dst_pid = nlk->dst_pid;
1139 dst_group = nlk->dst_group;
1140 }
1141
1142 if (!nlk->pid) {
1143 err = netlink_autobind(sock);
1144 if (err)
1145 goto out;
1146 }
1147
1148 err = -EMSGSIZE;
1149 if (len > sk->sk_sndbuf - 32)
1150 goto out;
1151 err = -ENOBUFS;
1152 skb = alloc_skb(len, GFP_KERNEL);
1153 if (skb==NULL)
1154 goto out;
1155
1156 NETLINK_CB(skb).pid = nlk->pid;
1157 NETLINK_CB(skb).dst_pid = dst_pid;
1158 NETLINK_CB(skb).dst_group = dst_group;
1159 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
1160 selinux_get_task_sid(current, &(NETLINK_CB(skb).sid));
1161 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1162
1163 /* What can I do? Netlink is asynchronous, so that
1164 we will have to save current capabilities to
1165 check them, when this message will be delivered
1166 to corresponding kernel module. --ANK (980802)
1167 */
1168
1169 err = -EFAULT;
1170 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) {
1171 kfree_skb(skb);
1172 goto out;
1173 }
1174
1175 err = security_netlink_send(sk, skb);
1176 if (err) {
1177 kfree_skb(skb);
1178 goto out;
1179 }
1180
1181 if (dst_group) {
1182 atomic_inc(&skb->users);
1183 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1184 }
1185 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1186
1187 out:
1188 return err;
1189 }
1190
1191 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1192 struct msghdr *msg, size_t len,
1193 int flags)
1194 {
1195 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1196 struct scm_cookie scm;
1197 struct sock *sk = sock->sk;
1198 struct netlink_sock *nlk = nlk_sk(sk);
1199 int noblock = flags&MSG_DONTWAIT;
1200 size_t copied;
1201 struct sk_buff *skb;
1202 int err;
1203
1204 if (flags&MSG_OOB)
1205 return -EOPNOTSUPP;
1206
1207 copied = 0;
1208
1209 skb = skb_recv_datagram(sk,flags,noblock,&err);
1210 if (skb==NULL)
1211 goto out;
1212
1213 msg->msg_namelen = 0;
1214
1215 copied = skb->len;
1216 if (len < copied) {
1217 msg->msg_flags |= MSG_TRUNC;
1218 copied = len;
1219 }
1220
1221 skb->h.raw = skb->data;
1222 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1223
1224 if (msg->msg_name) {
1225 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name;
1226 addr->nl_family = AF_NETLINK;
1227 addr->nl_pad = 0;
1228 addr->nl_pid = NETLINK_CB(skb).pid;
1229 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1230 msg->msg_namelen = sizeof(*addr);
1231 }
1232
1233 if (nlk->flags & NETLINK_RECV_PKTINFO)
1234 netlink_cmsg_recv_pktinfo(msg, skb);
1235
1236 if (NULL == siocb->scm) {
1237 memset(&scm, 0, sizeof(scm));
1238 siocb->scm = &scm;
1239 }
1240 siocb->scm->creds = *NETLINK_CREDS(skb);
1241 skb_free_datagram(sk, skb);
1242
1243 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1244 netlink_dump(sk);
1245
1246 scm_recv(sock, msg, siocb->scm, flags);
1247
1248 out:
1249 netlink_rcv_wake(sk);
1250 return err ? : copied;
1251 }
1252
1253 static void netlink_data_ready(struct sock *sk, int len)
1254 {
1255 struct netlink_sock *nlk = nlk_sk(sk);
1256
1257 if (nlk->data_ready)
1258 nlk->data_ready(sk, len);
1259 netlink_rcv_wake(sk);
1260 }
1261
1262 /*
1263 * We export these functions to other modules. They provide a
1264 * complete set of kernel non-blocking support for message
1265 * queueing.
1266 */
1267
1268 struct sock *
1269 netlink_kernel_create(int unit, unsigned int groups,
1270 void (*input)(struct sock *sk, int len),
1271 struct module *module)
1272 {
1273 struct socket *sock;
1274 struct sock *sk;
1275 struct netlink_sock *nlk;
1276 unsigned long *listeners = NULL;
1277
1278 if (!nl_table)
1279 return NULL;
1280
1281 if (unit<0 || unit>=MAX_LINKS)
1282 return NULL;
1283
1284 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1285 return NULL;
1286
1287 if (__netlink_create(sock, unit) < 0)
1288 goto out_sock_release;
1289
1290 if (groups < 32)
1291 groups = 32;
1292
1293 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
1294 if (!listeners)
1295 goto out_sock_release;
1296
1297 sk = sock->sk;
1298 sk->sk_data_ready = netlink_data_ready;
1299 if (input)
1300 nlk_sk(sk)->data_ready = input;
1301
1302 if (netlink_insert(sk, 0))
1303 goto out_sock_release;
1304
1305 nlk = nlk_sk(sk);
1306 nlk->flags |= NETLINK_KERNEL_SOCKET;
1307
1308 netlink_table_grab();
1309 nl_table[unit].groups = groups;
1310 nl_table[unit].listeners = listeners;
1311 nl_table[unit].module = module;
1312 nl_table[unit].registered = 1;
1313 netlink_table_ungrab();
1314
1315 return sk;
1316
1317 out_sock_release:
1318 kfree(listeners);
1319 sock_release(sock);
1320 return NULL;
1321 }
1322
1323 void netlink_set_nonroot(int protocol, unsigned int flags)
1324 {
1325 if ((unsigned int)protocol < MAX_LINKS)
1326 nl_table[protocol].nl_nonroot = flags;
1327 }
1328
1329 static void netlink_destroy_callback(struct netlink_callback *cb)
1330 {
1331 if (cb->skb)
1332 kfree_skb(cb->skb);
1333 kfree(cb);
1334 }
1335
1336 /*
1337 * It looks a bit ugly.
1338 * It would be better to create kernel thread.
1339 */
1340
1341 static int netlink_dump(struct sock *sk)
1342 {
1343 struct netlink_sock *nlk = nlk_sk(sk);
1344 struct netlink_callback *cb;
1345 struct sk_buff *skb;
1346 struct nlmsghdr *nlh;
1347 int len;
1348
1349 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1350 if (!skb)
1351 return -ENOBUFS;
1352
1353 spin_lock(&nlk->cb_lock);
1354
1355 cb = nlk->cb;
1356 if (cb == NULL) {
1357 spin_unlock(&nlk->cb_lock);
1358 kfree_skb(skb);
1359 return -EINVAL;
1360 }
1361
1362 len = cb->dump(skb, cb);
1363
1364 if (len > 0) {
1365 spin_unlock(&nlk->cb_lock);
1366 skb_queue_tail(&sk->sk_receive_queue, skb);
1367 sk->sk_data_ready(sk, len);
1368 return 0;
1369 }
1370
1371 nlh = NLMSG_NEW_ANSWER(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1372 memcpy(NLMSG_DATA(nlh), &len, sizeof(len));
1373 skb_queue_tail(&sk->sk_receive_queue, skb);
1374 sk->sk_data_ready(sk, skb->len);
1375
1376 if (cb->done)
1377 cb->done(cb);
1378 nlk->cb = NULL;
1379 spin_unlock(&nlk->cb_lock);
1380
1381 netlink_destroy_callback(cb);
1382 return 0;
1383
1384 nlmsg_failure:
1385 return -ENOBUFS;
1386 }
1387
1388 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1389 struct nlmsghdr *nlh,
1390 int (*dump)(struct sk_buff *skb, struct netlink_callback*),
1391 int (*done)(struct netlink_callback*))
1392 {
1393 struct netlink_callback *cb;
1394 struct sock *sk;
1395 struct netlink_sock *nlk;
1396
1397 cb = kmalloc(sizeof(*cb), GFP_KERNEL);
1398 if (cb == NULL)
1399 return -ENOBUFS;
1400
1401 memset(cb, 0, sizeof(*cb));
1402 cb->dump = dump;
1403 cb->done = done;
1404 cb->nlh = nlh;
1405 atomic_inc(&skb->users);
1406 cb->skb = skb;
1407
1408 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid);
1409 if (sk == NULL) {
1410 netlink_destroy_callback(cb);
1411 return -ECONNREFUSED;
1412 }
1413 nlk = nlk_sk(sk);
1414 /* A dump is in progress... */
1415 spin_lock(&nlk->cb_lock);
1416 if (nlk->cb) {
1417 spin_unlock(&nlk->cb_lock);
1418 netlink_destroy_callback(cb);
1419 sock_put(sk);
1420 return -EBUSY;
1421 }
1422 nlk->cb = cb;
1423 spin_unlock(&nlk->cb_lock);
1424
1425 netlink_dump(sk);
1426 sock_put(sk);
1427 return 0;
1428 }
1429
1430 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1431 {
1432 struct sk_buff *skb;
1433 struct nlmsghdr *rep;
1434 struct nlmsgerr *errmsg;
1435 int size;
1436
1437 if (err == 0)
1438 size = NLMSG_SPACE(sizeof(struct nlmsgerr));
1439 else
1440 size = NLMSG_SPACE(4 + NLMSG_ALIGN(nlh->nlmsg_len));
1441
1442 skb = alloc_skb(size, GFP_KERNEL);
1443 if (!skb) {
1444 struct sock *sk;
1445
1446 sk = netlink_lookup(in_skb->sk->sk_protocol,
1447 NETLINK_CB(in_skb).pid);
1448 if (sk) {
1449 sk->sk_err = ENOBUFS;
1450 sk->sk_error_report(sk);
1451 sock_put(sk);
1452 }
1453 return;
1454 }
1455
1456 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1457 NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
1458 errmsg = NLMSG_DATA(rep);
1459 errmsg->error = err;
1460 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(struct nlmsghdr));
1461 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1462 }
1463
1464 static int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1465 struct nlmsghdr *, int *))
1466 {
1467 unsigned int total_len;
1468 struct nlmsghdr *nlh;
1469 int err;
1470
1471 while (skb->len >= nlmsg_total_size(0)) {
1472 nlh = (struct nlmsghdr *) skb->data;
1473
1474 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1475 return 0;
1476
1477 total_len = min(NLMSG_ALIGN(nlh->nlmsg_len), skb->len);
1478
1479 if (cb(skb, nlh, &err) < 0) {
1480 /* Not an error, but we have to interrupt processing
1481 * here. Note: that in this case we do not pull
1482 * message from skb, it will be processed later.
1483 */
1484 if (err == 0)
1485 return -1;
1486 netlink_ack(skb, nlh, err);
1487 } else if (nlh->nlmsg_flags & NLM_F_ACK)
1488 netlink_ack(skb, nlh, 0);
1489
1490 skb_pull(skb, total_len);
1491 }
1492
1493 return 0;
1494 }
1495
1496 /**
1497 * nelink_run_queue - Process netlink receive queue.
1498 * @sk: Netlink socket containing the queue
1499 * @qlen: Place to store queue length upon entry
1500 * @cb: Callback function invoked for each netlink message found
1501 *
1502 * Processes as much as there was in the queue upon entry and invokes
1503 * a callback function for each netlink message found. The callback
1504 * function may refuse a message by returning a negative error code
1505 * but setting the error pointer to 0 in which case this function
1506 * returns with a qlen != 0.
1507 *
1508 * qlen must be initialized to 0 before the initial entry, afterwards
1509 * the function may be called repeatedly until qlen reaches 0.
1510 */
1511 void netlink_run_queue(struct sock *sk, unsigned int *qlen,
1512 int (*cb)(struct sk_buff *, struct nlmsghdr *, int *))
1513 {
1514 struct sk_buff *skb;
1515
1516 if (!*qlen || *qlen > skb_queue_len(&sk->sk_receive_queue))
1517 *qlen = skb_queue_len(&sk->sk_receive_queue);
1518
1519 for (; *qlen; (*qlen)--) {
1520 skb = skb_dequeue(&sk->sk_receive_queue);
1521 if (netlink_rcv_skb(skb, cb)) {
1522 if (skb->len)
1523 skb_queue_head(&sk->sk_receive_queue, skb);
1524 else {
1525 kfree_skb(skb);
1526 (*qlen)--;
1527 }
1528 break;
1529 }
1530
1531 kfree_skb(skb);
1532 }
1533 }
1534
1535 /**
1536 * netlink_queue_skip - Skip netlink message while processing queue.
1537 * @nlh: Netlink message to be skipped
1538 * @skb: Socket buffer containing the netlink messages.
1539 *
1540 * Pulls the given netlink message off the socket buffer so the next
1541 * call to netlink_queue_run() will not reconsider the message.
1542 */
1543 void netlink_queue_skip(struct nlmsghdr *nlh, struct sk_buff *skb)
1544 {
1545 int msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1546
1547 if (msglen > skb->len)
1548 msglen = skb->len;
1549
1550 skb_pull(skb, msglen);
1551 }
1552
1553 #ifdef CONFIG_PROC_FS
1554 struct nl_seq_iter {
1555 int link;
1556 int hash_idx;
1557 };
1558
1559 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1560 {
1561 struct nl_seq_iter *iter = seq->private;
1562 int i, j;
1563 struct sock *s;
1564 struct hlist_node *node;
1565 loff_t off = 0;
1566
1567 for (i=0; i<MAX_LINKS; i++) {
1568 struct nl_pid_hash *hash = &nl_table[i].hash;
1569
1570 for (j = 0; j <= hash->mask; j++) {
1571 sk_for_each(s, node, &hash->table[j]) {
1572 if (off == pos) {
1573 iter->link = i;
1574 iter->hash_idx = j;
1575 return s;
1576 }
1577 ++off;
1578 }
1579 }
1580 }
1581 return NULL;
1582 }
1583
1584 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1585 {
1586 read_lock(&nl_table_lock);
1587 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1588 }
1589
1590 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1591 {
1592 struct sock *s;
1593 struct nl_seq_iter *iter;
1594 int i, j;
1595
1596 ++*pos;
1597
1598 if (v == SEQ_START_TOKEN)
1599 return netlink_seq_socket_idx(seq, 0);
1600
1601 s = sk_next(v);
1602 if (s)
1603 return s;
1604
1605 iter = seq->private;
1606 i = iter->link;
1607 j = iter->hash_idx + 1;
1608
1609 do {
1610 struct nl_pid_hash *hash = &nl_table[i].hash;
1611
1612 for (; j <= hash->mask; j++) {
1613 s = sk_head(&hash->table[j]);
1614 if (s) {
1615 iter->link = i;
1616 iter->hash_idx = j;
1617 return s;
1618 }
1619 }
1620
1621 j = 0;
1622 } while (++i < MAX_LINKS);
1623
1624 return NULL;
1625 }
1626
1627 static void netlink_seq_stop(struct seq_file *seq, void *v)
1628 {
1629 read_unlock(&nl_table_lock);
1630 }
1631
1632
1633 static int netlink_seq_show(struct seq_file *seq, void *v)
1634 {
1635 if (v == SEQ_START_TOKEN)
1636 seq_puts(seq,
1637 "sk Eth Pid Groups "
1638 "Rmem Wmem Dump Locks\n");
1639 else {
1640 struct sock *s = v;
1641 struct netlink_sock *nlk = nlk_sk(s);
1642
1643 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
1644 s,
1645 s->sk_protocol,
1646 nlk->pid,
1647 nlk->groups ? (u32)nlk->groups[0] : 0,
1648 atomic_read(&s->sk_rmem_alloc),
1649 atomic_read(&s->sk_wmem_alloc),
1650 nlk->cb,
1651 atomic_read(&s->sk_refcnt)
1652 );
1653
1654 }
1655 return 0;
1656 }
1657
1658 static struct seq_operations netlink_seq_ops = {
1659 .start = netlink_seq_start,
1660 .next = netlink_seq_next,
1661 .stop = netlink_seq_stop,
1662 .show = netlink_seq_show,
1663 };
1664
1665
1666 static int netlink_seq_open(struct inode *inode, struct file *file)
1667 {
1668 struct seq_file *seq;
1669 struct nl_seq_iter *iter;
1670 int err;
1671
1672 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
1673 if (!iter)
1674 return -ENOMEM;
1675
1676 err = seq_open(file, &netlink_seq_ops);
1677 if (err) {
1678 kfree(iter);
1679 return err;
1680 }
1681
1682 memset(iter, 0, sizeof(*iter));
1683 seq = file->private_data;
1684 seq->private = iter;
1685 return 0;
1686 }
1687
1688 static struct file_operations netlink_seq_fops = {
1689 .owner = THIS_MODULE,
1690 .open = netlink_seq_open,
1691 .read = seq_read,
1692 .llseek = seq_lseek,
1693 .release = seq_release_private,
1694 };
1695
1696 #endif
1697
1698 int netlink_register_notifier(struct notifier_block *nb)
1699 {
1700 return atomic_notifier_chain_register(&netlink_chain, nb);
1701 }
1702
1703 int netlink_unregister_notifier(struct notifier_block *nb)
1704 {
1705 return atomic_notifier_chain_unregister(&netlink_chain, nb);
1706 }
1707
1708 static const struct proto_ops netlink_ops = {
1709 .family = PF_NETLINK,
1710 .owner = THIS_MODULE,
1711 .release = netlink_release,
1712 .bind = netlink_bind,
1713 .connect = netlink_connect,
1714 .socketpair = sock_no_socketpair,
1715 .accept = sock_no_accept,
1716 .getname = netlink_getname,
1717 .poll = datagram_poll,
1718 .ioctl = sock_no_ioctl,
1719 .listen = sock_no_listen,
1720 .shutdown = sock_no_shutdown,
1721 .setsockopt = netlink_setsockopt,
1722 .getsockopt = netlink_getsockopt,
1723 .sendmsg = netlink_sendmsg,
1724 .recvmsg = netlink_recvmsg,
1725 .mmap = sock_no_mmap,
1726 .sendpage = sock_no_sendpage,
1727 };
1728
1729 static struct net_proto_family netlink_family_ops = {
1730 .family = PF_NETLINK,
1731 .create = netlink_create,
1732 .owner = THIS_MODULE, /* for consistency 8) */
1733 };
1734
1735 extern void netlink_skb_parms_too_large(void);
1736
1737 static int __init netlink_proto_init(void)
1738 {
1739 struct sk_buff *dummy_skb;
1740 int i;
1741 unsigned long max;
1742 unsigned int order;
1743 int err = proto_register(&netlink_proto, 0);
1744
1745 if (err != 0)
1746 goto out;
1747
1748 if (sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb))
1749 netlink_skb_parms_too_large();
1750
1751 nl_table = kmalloc(sizeof(*nl_table) * MAX_LINKS, GFP_KERNEL);
1752 if (!nl_table) {
1753 enomem:
1754 printk(KERN_CRIT "netlink_init: Cannot allocate nl_table\n");
1755 return -ENOMEM;
1756 }
1757
1758 memset(nl_table, 0, sizeof(*nl_table) * MAX_LINKS);
1759
1760 if (num_physpages >= (128 * 1024))
1761 max = num_physpages >> (21 - PAGE_SHIFT);
1762 else
1763 max = num_physpages >> (23 - PAGE_SHIFT);
1764
1765 order = get_bitmask_order(max) - 1 + PAGE_SHIFT;
1766 max = (1UL << order) / sizeof(struct hlist_head);
1767 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1;
1768
1769 for (i = 0; i < MAX_LINKS; i++) {
1770 struct nl_pid_hash *hash = &nl_table[i].hash;
1771
1772 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table));
1773 if (!hash->table) {
1774 while (i-- > 0)
1775 nl_pid_hash_free(nl_table[i].hash.table,
1776 1 * sizeof(*hash->table));
1777 kfree(nl_table);
1778 goto enomem;
1779 }
1780 memset(hash->table, 0, 1 * sizeof(*hash->table));
1781 hash->max_shift = order;
1782 hash->shift = 0;
1783 hash->mask = 0;
1784 hash->rehash_time = jiffies;
1785 }
1786
1787 sock_register(&netlink_family_ops);
1788 #ifdef CONFIG_PROC_FS
1789 proc_net_fops_create("netlink", 0, &netlink_seq_fops);
1790 #endif
1791 /* The netlink device handler may be needed early. */
1792 rtnetlink_init();
1793 out:
1794 return err;
1795 }
1796
1797 core_initcall(netlink_proto_init);
1798
1799 EXPORT_SYMBOL(netlink_ack);
1800 EXPORT_SYMBOL(netlink_run_queue);
1801 EXPORT_SYMBOL(netlink_queue_skip);
1802 EXPORT_SYMBOL(netlink_broadcast);
1803 EXPORT_SYMBOL(netlink_dump_start);
1804 EXPORT_SYMBOL(netlink_kernel_create);
1805 EXPORT_SYMBOL(netlink_register_notifier);
1806 EXPORT_SYMBOL(netlink_set_err);
1807 EXPORT_SYMBOL(netlink_set_nonroot);
1808 EXPORT_SYMBOL(netlink_unicast);
1809 EXPORT_SYMBOL(netlink_unregister_notifier);
1810