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Merge branch 'release' of git://lm-sensors.org/kernel/mhoffman/hwmon-2.6
[mirror_ubuntu-bionic-kernel.git] / net / netlink / af_netlink.c
1 /*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@redhat.com>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
13 * added netlink_proto_exit
14 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
15 * use nlk_sk, as sk->protinfo is on a diet 8)
16 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
17 * - inc module use count of module that owns
18 * the kernel socket in case userspace opens
19 * socket of same protocol
20 * - remove all module support, since netlink is
21 * mandatory if CONFIG_NET=y these days
22 */
23
24 #include <linux/module.h>
25
26 #include <linux/capability.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/signal.h>
30 #include <linux/sched.h>
31 #include <linux/errno.h>
32 #include <linux/string.h>
33 #include <linux/stat.h>
34 #include <linux/socket.h>
35 #include <linux/un.h>
36 #include <linux/fcntl.h>
37 #include <linux/termios.h>
38 #include <linux/sockios.h>
39 #include <linux/net.h>
40 #include <linux/fs.h>
41 #include <linux/slab.h>
42 #include <asm/uaccess.h>
43 #include <linux/skbuff.h>
44 #include <linux/netdevice.h>
45 #include <linux/rtnetlink.h>
46 #include <linux/proc_fs.h>
47 #include <linux/seq_file.h>
48 #include <linux/notifier.h>
49 #include <linux/security.h>
50 #include <linux/jhash.h>
51 #include <linux/jiffies.h>
52 #include <linux/random.h>
53 #include <linux/bitops.h>
54 #include <linux/mm.h>
55 #include <linux/types.h>
56 #include <linux/audit.h>
57 #include <linux/selinux.h>
58 #include <linux/mutex.h>
59
60 #include <net/net_namespace.h>
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 #define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long))
67
68 struct netlink_sock {
69 /* struct sock has to be the first member of netlink_sock */
70 struct sock sk;
71 u32 pid;
72 u32 dst_pid;
73 u32 dst_group;
74 u32 flags;
75 u32 subscriptions;
76 u32 ngroups;
77 unsigned long *groups;
78 unsigned long state;
79 wait_queue_head_t wait;
80 struct netlink_callback *cb;
81 struct mutex *cb_mutex;
82 struct mutex cb_def_mutex;
83 void (*netlink_rcv)(struct sk_buff *skb);
84 struct module *module;
85 };
86
87 #define NETLINK_KERNEL_SOCKET 0x1
88 #define NETLINK_RECV_PKTINFO 0x2
89
90 static inline struct netlink_sock *nlk_sk(struct sock *sk)
91 {
92 return container_of(sk, struct netlink_sock, sk);
93 }
94
95 static inline int netlink_is_kernel(struct sock *sk)
96 {
97 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
98 }
99
100 struct nl_pid_hash {
101 struct hlist_head *table;
102 unsigned long rehash_time;
103
104 unsigned int mask;
105 unsigned int shift;
106
107 unsigned int entries;
108 unsigned int max_shift;
109
110 u32 rnd;
111 };
112
113 struct netlink_table {
114 struct nl_pid_hash hash;
115 struct hlist_head mc_list;
116 unsigned long *listeners;
117 unsigned int nl_nonroot;
118 unsigned int groups;
119 struct mutex *cb_mutex;
120 struct module *module;
121 int registered;
122 };
123
124 static struct netlink_table *nl_table;
125
126 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
127
128 static int netlink_dump(struct sock *sk);
129 static void netlink_destroy_callback(struct netlink_callback *cb);
130
131 static DEFINE_RWLOCK(nl_table_lock);
132 static atomic_t nl_table_users = ATOMIC_INIT(0);
133
134 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
135
136 static u32 netlink_group_mask(u32 group)
137 {
138 return group ? 1 << (group - 1) : 0;
139 }
140
141 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
142 {
143 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
144 }
145
146 static void netlink_sock_destruct(struct sock *sk)
147 {
148 struct netlink_sock *nlk = nlk_sk(sk);
149
150 if (nlk->cb) {
151 if (nlk->cb->done)
152 nlk->cb->done(nlk->cb);
153 netlink_destroy_callback(nlk->cb);
154 }
155
156 skb_queue_purge(&sk->sk_receive_queue);
157
158 if (!sock_flag(sk, SOCK_DEAD)) {
159 printk("Freeing alive netlink socket %p\n", sk);
160 return;
161 }
162 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
163 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
164 BUG_TRAP(!nlk_sk(sk)->groups);
165 }
166
167 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
168 * Look, when several writers sleep and reader wakes them up, all but one
169 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
170 * this, _but_ remember, it adds useless work on UP machines.
171 */
172
173 static void netlink_table_grab(void)
174 {
175 write_lock_irq(&nl_table_lock);
176
177 if (atomic_read(&nl_table_users)) {
178 DECLARE_WAITQUEUE(wait, current);
179
180 add_wait_queue_exclusive(&nl_table_wait, &wait);
181 for(;;) {
182 set_current_state(TASK_UNINTERRUPTIBLE);
183 if (atomic_read(&nl_table_users) == 0)
184 break;
185 write_unlock_irq(&nl_table_lock);
186 schedule();
187 write_lock_irq(&nl_table_lock);
188 }
189
190 __set_current_state(TASK_RUNNING);
191 remove_wait_queue(&nl_table_wait, &wait);
192 }
193 }
194
195 static __inline__ void netlink_table_ungrab(void)
196 {
197 write_unlock_irq(&nl_table_lock);
198 wake_up(&nl_table_wait);
199 }
200
201 static __inline__ void
202 netlink_lock_table(void)
203 {
204 /* read_lock() synchronizes us to netlink_table_grab */
205
206 read_lock(&nl_table_lock);
207 atomic_inc(&nl_table_users);
208 read_unlock(&nl_table_lock);
209 }
210
211 static __inline__ void
212 netlink_unlock_table(void)
213 {
214 if (atomic_dec_and_test(&nl_table_users))
215 wake_up(&nl_table_wait);
216 }
217
218 static __inline__ struct sock *netlink_lookup(struct net *net, int protocol, u32 pid)
219 {
220 struct nl_pid_hash *hash = &nl_table[protocol].hash;
221 struct hlist_head *head;
222 struct sock *sk;
223 struct hlist_node *node;
224
225 read_lock(&nl_table_lock);
226 head = nl_pid_hashfn(hash, pid);
227 sk_for_each(sk, node, head) {
228 if ((sk->sk_net == net) && (nlk_sk(sk)->pid == pid)) {
229 sock_hold(sk);
230 goto found;
231 }
232 }
233 sk = NULL;
234 found:
235 read_unlock(&nl_table_lock);
236 return sk;
237 }
238
239 static inline struct hlist_head *nl_pid_hash_alloc(size_t size)
240 {
241 if (size <= PAGE_SIZE)
242 return kmalloc(size, GFP_ATOMIC);
243 else
244 return (struct hlist_head *)
245 __get_free_pages(GFP_ATOMIC, get_order(size));
246 }
247
248 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
249 {
250 if (size <= PAGE_SIZE)
251 kfree(table);
252 else
253 free_pages((unsigned long)table, get_order(size));
254 }
255
256 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
257 {
258 unsigned int omask, mask, shift;
259 size_t osize, size;
260 struct hlist_head *otable, *table;
261 int i;
262
263 omask = mask = hash->mask;
264 osize = size = (mask + 1) * sizeof(*table);
265 shift = hash->shift;
266
267 if (grow) {
268 if (++shift > hash->max_shift)
269 return 0;
270 mask = mask * 2 + 1;
271 size *= 2;
272 }
273
274 table = nl_pid_hash_alloc(size);
275 if (!table)
276 return 0;
277
278 memset(table, 0, size);
279 otable = hash->table;
280 hash->table = table;
281 hash->mask = mask;
282 hash->shift = shift;
283 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
284
285 for (i = 0; i <= omask; i++) {
286 struct sock *sk;
287 struct hlist_node *node, *tmp;
288
289 sk_for_each_safe(sk, node, tmp, &otable[i])
290 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
291 }
292
293 nl_pid_hash_free(otable, osize);
294 hash->rehash_time = jiffies + 10 * 60 * HZ;
295 return 1;
296 }
297
298 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
299 {
300 int avg = hash->entries >> hash->shift;
301
302 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
303 return 1;
304
305 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
306 nl_pid_hash_rehash(hash, 0);
307 return 1;
308 }
309
310 return 0;
311 }
312
313 static const struct proto_ops netlink_ops;
314
315 static void
316 netlink_update_listeners(struct sock *sk)
317 {
318 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
319 struct hlist_node *node;
320 unsigned long mask;
321 unsigned int i;
322
323 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
324 mask = 0;
325 sk_for_each_bound(sk, node, &tbl->mc_list) {
326 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
327 mask |= nlk_sk(sk)->groups[i];
328 }
329 tbl->listeners[i] = mask;
330 }
331 /* this function is only called with the netlink table "grabbed", which
332 * makes sure updates are visible before bind or setsockopt return. */
333 }
334
335 static int netlink_insert(struct sock *sk, struct net *net, u32 pid)
336 {
337 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
338 struct hlist_head *head;
339 int err = -EADDRINUSE;
340 struct sock *osk;
341 struct hlist_node *node;
342 int len;
343
344 netlink_table_grab();
345 head = nl_pid_hashfn(hash, pid);
346 len = 0;
347 sk_for_each(osk, node, head) {
348 if ((osk->sk_net == net) && (nlk_sk(osk)->pid == pid))
349 break;
350 len++;
351 }
352 if (node)
353 goto err;
354
355 err = -EBUSY;
356 if (nlk_sk(sk)->pid)
357 goto err;
358
359 err = -ENOMEM;
360 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
361 goto err;
362
363 if (len && nl_pid_hash_dilute(hash, len))
364 head = nl_pid_hashfn(hash, pid);
365 hash->entries++;
366 nlk_sk(sk)->pid = pid;
367 sk_add_node(sk, head);
368 err = 0;
369
370 err:
371 netlink_table_ungrab();
372 return err;
373 }
374
375 static void netlink_remove(struct sock *sk)
376 {
377 netlink_table_grab();
378 if (sk_del_node_init(sk))
379 nl_table[sk->sk_protocol].hash.entries--;
380 if (nlk_sk(sk)->subscriptions)
381 __sk_del_bind_node(sk);
382 netlink_table_ungrab();
383 }
384
385 static struct proto netlink_proto = {
386 .name = "NETLINK",
387 .owner = THIS_MODULE,
388 .obj_size = sizeof(struct netlink_sock),
389 };
390
391 static int __netlink_create(struct net *net, struct socket *sock,
392 struct mutex *cb_mutex, int protocol)
393 {
394 struct sock *sk;
395 struct netlink_sock *nlk;
396
397 sock->ops = &netlink_ops;
398
399 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
400 if (!sk)
401 return -ENOMEM;
402
403 sock_init_data(sock, sk);
404
405 nlk = nlk_sk(sk);
406 if (cb_mutex)
407 nlk->cb_mutex = cb_mutex;
408 else {
409 nlk->cb_mutex = &nlk->cb_def_mutex;
410 mutex_init(nlk->cb_mutex);
411 }
412 init_waitqueue_head(&nlk->wait);
413
414 sk->sk_destruct = netlink_sock_destruct;
415 sk->sk_protocol = protocol;
416 return 0;
417 }
418
419 static int netlink_create(struct net *net, struct socket *sock, int protocol)
420 {
421 struct module *module = NULL;
422 struct mutex *cb_mutex;
423 struct netlink_sock *nlk;
424 int err = 0;
425
426 sock->state = SS_UNCONNECTED;
427
428 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
429 return -ESOCKTNOSUPPORT;
430
431 if (protocol<0 || protocol >= MAX_LINKS)
432 return -EPROTONOSUPPORT;
433
434 netlink_lock_table();
435 #ifdef CONFIG_KMOD
436 if (!nl_table[protocol].registered) {
437 netlink_unlock_table();
438 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
439 netlink_lock_table();
440 }
441 #endif
442 if (nl_table[protocol].registered &&
443 try_module_get(nl_table[protocol].module))
444 module = nl_table[protocol].module;
445 cb_mutex = nl_table[protocol].cb_mutex;
446 netlink_unlock_table();
447
448 if ((err = __netlink_create(net, sock, cb_mutex, protocol)) < 0)
449 goto out_module;
450
451 nlk = nlk_sk(sock->sk);
452 nlk->module = module;
453 out:
454 return err;
455
456 out_module:
457 module_put(module);
458 goto out;
459 }
460
461 static int netlink_release(struct socket *sock)
462 {
463 struct sock *sk = sock->sk;
464 struct netlink_sock *nlk;
465
466 if (!sk)
467 return 0;
468
469 netlink_remove(sk);
470 sock_orphan(sk);
471 nlk = nlk_sk(sk);
472
473 /*
474 * OK. Socket is unlinked, any packets that arrive now
475 * will be purged.
476 */
477
478 sock->sk = NULL;
479 wake_up_interruptible_all(&nlk->wait);
480
481 skb_queue_purge(&sk->sk_write_queue);
482
483 if (nlk->pid && !nlk->subscriptions) {
484 struct netlink_notify n = {
485 .net = sk->sk_net,
486 .protocol = sk->sk_protocol,
487 .pid = nlk->pid,
488 };
489 atomic_notifier_call_chain(&netlink_chain,
490 NETLINK_URELEASE, &n);
491 }
492
493 module_put(nlk->module);
494
495 netlink_table_grab();
496 if (netlink_is_kernel(sk)) {
497 kfree(nl_table[sk->sk_protocol].listeners);
498 nl_table[sk->sk_protocol].module = NULL;
499 nl_table[sk->sk_protocol].registered = 0;
500 } else if (nlk->subscriptions)
501 netlink_update_listeners(sk);
502 netlink_table_ungrab();
503
504 kfree(nlk->groups);
505 nlk->groups = NULL;
506
507 sock_put(sk);
508 return 0;
509 }
510
511 static int netlink_autobind(struct socket *sock)
512 {
513 struct sock *sk = sock->sk;
514 struct net *net = sk->sk_net;
515 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
516 struct hlist_head *head;
517 struct sock *osk;
518 struct hlist_node *node;
519 s32 pid = current->tgid;
520 int err;
521 static s32 rover = -4097;
522
523 retry:
524 cond_resched();
525 netlink_table_grab();
526 head = nl_pid_hashfn(hash, pid);
527 sk_for_each(osk, node, head) {
528 if ((osk->sk_net != net))
529 continue;
530 if (nlk_sk(osk)->pid == pid) {
531 /* Bind collision, search negative pid values. */
532 pid = rover--;
533 if (rover > -4097)
534 rover = -4097;
535 netlink_table_ungrab();
536 goto retry;
537 }
538 }
539 netlink_table_ungrab();
540
541 err = netlink_insert(sk, net, pid);
542 if (err == -EADDRINUSE)
543 goto retry;
544
545 /* If 2 threads race to autobind, that is fine. */
546 if (err == -EBUSY)
547 err = 0;
548
549 return err;
550 }
551
552 static inline int netlink_capable(struct socket *sock, unsigned int flag)
553 {
554 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
555 capable(CAP_NET_ADMIN);
556 }
557
558 static void
559 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
560 {
561 struct netlink_sock *nlk = nlk_sk(sk);
562
563 if (nlk->subscriptions && !subscriptions)
564 __sk_del_bind_node(sk);
565 else if (!nlk->subscriptions && subscriptions)
566 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
567 nlk->subscriptions = subscriptions;
568 }
569
570 static int netlink_realloc_groups(struct sock *sk)
571 {
572 struct netlink_sock *nlk = nlk_sk(sk);
573 unsigned int groups;
574 unsigned long *new_groups;
575 int err = 0;
576
577 netlink_table_grab();
578
579 groups = nl_table[sk->sk_protocol].groups;
580 if (!nl_table[sk->sk_protocol].registered) {
581 err = -ENOENT;
582 goto out_unlock;
583 }
584
585 if (nlk->ngroups >= groups)
586 goto out_unlock;
587
588 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
589 if (new_groups == NULL) {
590 err = -ENOMEM;
591 goto out_unlock;
592 }
593 memset((char*)new_groups + NLGRPSZ(nlk->ngroups), 0,
594 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
595
596 nlk->groups = new_groups;
597 nlk->ngroups = groups;
598 out_unlock:
599 netlink_table_ungrab();
600 return err;
601 }
602
603 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
604 {
605 struct sock *sk = sock->sk;
606 struct net *net = sk->sk_net;
607 struct netlink_sock *nlk = nlk_sk(sk);
608 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
609 int err;
610
611 if (nladdr->nl_family != AF_NETLINK)
612 return -EINVAL;
613
614 /* Only superuser is allowed to listen multicasts */
615 if (nladdr->nl_groups) {
616 if (!netlink_capable(sock, NL_NONROOT_RECV))
617 return -EPERM;
618 err = netlink_realloc_groups(sk);
619 if (err)
620 return err;
621 }
622
623 if (nlk->pid) {
624 if (nladdr->nl_pid != nlk->pid)
625 return -EINVAL;
626 } else {
627 err = nladdr->nl_pid ?
628 netlink_insert(sk, net, nladdr->nl_pid) :
629 netlink_autobind(sock);
630 if (err)
631 return err;
632 }
633
634 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
635 return 0;
636
637 netlink_table_grab();
638 netlink_update_subscriptions(sk, nlk->subscriptions +
639 hweight32(nladdr->nl_groups) -
640 hweight32(nlk->groups[0]));
641 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
642 netlink_update_listeners(sk);
643 netlink_table_ungrab();
644
645 return 0;
646 }
647
648 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
649 int alen, int flags)
650 {
651 int err = 0;
652 struct sock *sk = sock->sk;
653 struct netlink_sock *nlk = nlk_sk(sk);
654 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr;
655
656 if (addr->sa_family == AF_UNSPEC) {
657 sk->sk_state = NETLINK_UNCONNECTED;
658 nlk->dst_pid = 0;
659 nlk->dst_group = 0;
660 return 0;
661 }
662 if (addr->sa_family != AF_NETLINK)
663 return -EINVAL;
664
665 /* Only superuser is allowed to send multicasts */
666 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
667 return -EPERM;
668
669 if (!nlk->pid)
670 err = netlink_autobind(sock);
671
672 if (err == 0) {
673 sk->sk_state = NETLINK_CONNECTED;
674 nlk->dst_pid = nladdr->nl_pid;
675 nlk->dst_group = ffs(nladdr->nl_groups);
676 }
677
678 return err;
679 }
680
681 static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer)
682 {
683 struct sock *sk = sock->sk;
684 struct netlink_sock *nlk = nlk_sk(sk);
685 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr;
686
687 nladdr->nl_family = AF_NETLINK;
688 nladdr->nl_pad = 0;
689 *addr_len = sizeof(*nladdr);
690
691 if (peer) {
692 nladdr->nl_pid = nlk->dst_pid;
693 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
694 } else {
695 nladdr->nl_pid = nlk->pid;
696 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
697 }
698 return 0;
699 }
700
701 static void netlink_overrun(struct sock *sk)
702 {
703 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
704 sk->sk_err = ENOBUFS;
705 sk->sk_error_report(sk);
706 }
707 }
708
709 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
710 {
711 struct sock *sock;
712 struct netlink_sock *nlk;
713
714 sock = netlink_lookup(ssk->sk_net, ssk->sk_protocol, pid);
715 if (!sock)
716 return ERR_PTR(-ECONNREFUSED);
717
718 /* Don't bother queuing skb if kernel socket has no input function */
719 nlk = nlk_sk(sock);
720 if (sock->sk_state == NETLINK_CONNECTED &&
721 nlk->dst_pid != nlk_sk(ssk)->pid) {
722 sock_put(sock);
723 return ERR_PTR(-ECONNREFUSED);
724 }
725 return sock;
726 }
727
728 struct sock *netlink_getsockbyfilp(struct file *filp)
729 {
730 struct inode *inode = filp->f_path.dentry->d_inode;
731 struct sock *sock;
732
733 if (!S_ISSOCK(inode->i_mode))
734 return ERR_PTR(-ENOTSOCK);
735
736 sock = SOCKET_I(inode)->sk;
737 if (sock->sk_family != AF_NETLINK)
738 return ERR_PTR(-EINVAL);
739
740 sock_hold(sock);
741 return sock;
742 }
743
744 /*
745 * Attach a skb to a netlink socket.
746 * The caller must hold a reference to the destination socket. On error, the
747 * reference is dropped. The skb is not send to the destination, just all
748 * all error checks are performed and memory in the queue is reserved.
749 * Return values:
750 * < 0: error. skb freed, reference to sock dropped.
751 * 0: continue
752 * 1: repeat lookup - reference dropped while waiting for socket memory.
753 */
754 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock,
755 long timeo, struct sock *ssk)
756 {
757 struct netlink_sock *nlk;
758
759 nlk = nlk_sk(sk);
760
761 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
762 test_bit(0, &nlk->state)) {
763 DECLARE_WAITQUEUE(wait, current);
764 if (!timeo) {
765 if (!ssk || netlink_is_kernel(ssk))
766 netlink_overrun(sk);
767 sock_put(sk);
768 kfree_skb(skb);
769 return -EAGAIN;
770 }
771
772 __set_current_state(TASK_INTERRUPTIBLE);
773 add_wait_queue(&nlk->wait, &wait);
774
775 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
776 test_bit(0, &nlk->state)) &&
777 !sock_flag(sk, SOCK_DEAD))
778 timeo = schedule_timeout(timeo);
779
780 __set_current_state(TASK_RUNNING);
781 remove_wait_queue(&nlk->wait, &wait);
782 sock_put(sk);
783
784 if (signal_pending(current)) {
785 kfree_skb(skb);
786 return sock_intr_errno(timeo);
787 }
788 return 1;
789 }
790 skb_set_owner_r(skb, sk);
791 return 0;
792 }
793
794 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
795 {
796 int len = skb->len;
797
798 skb_queue_tail(&sk->sk_receive_queue, skb);
799 sk->sk_data_ready(sk, len);
800 sock_put(sk);
801 return len;
802 }
803
804 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
805 {
806 kfree_skb(skb);
807 sock_put(sk);
808 }
809
810 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
811 gfp_t allocation)
812 {
813 int delta;
814
815 skb_orphan(skb);
816
817 delta = skb->end - skb->tail;
818 if (delta * 2 < skb->truesize)
819 return skb;
820
821 if (skb_shared(skb)) {
822 struct sk_buff *nskb = skb_clone(skb, allocation);
823 if (!nskb)
824 return skb;
825 kfree_skb(skb);
826 skb = nskb;
827 }
828
829 if (!pskb_expand_head(skb, 0, -delta, allocation))
830 skb->truesize -= delta;
831
832 return skb;
833 }
834
835 static inline void netlink_rcv_wake(struct sock *sk)
836 {
837 struct netlink_sock *nlk = nlk_sk(sk);
838
839 if (skb_queue_empty(&sk->sk_receive_queue))
840 clear_bit(0, &nlk->state);
841 if (!test_bit(0, &nlk->state))
842 wake_up_interruptible(&nlk->wait);
843 }
844
845 static inline int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb)
846 {
847 int ret;
848 struct netlink_sock *nlk = nlk_sk(sk);
849
850 ret = -ECONNREFUSED;
851 if (nlk->netlink_rcv != NULL) {
852 ret = skb->len;
853 skb_set_owner_r(skb, sk);
854 nlk->netlink_rcv(skb);
855 }
856 kfree_skb(skb);
857 sock_put(sk);
858 return ret;
859 }
860
861 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
862 u32 pid, int nonblock)
863 {
864 struct sock *sk;
865 int err;
866 long timeo;
867
868 skb = netlink_trim(skb, gfp_any());
869
870 timeo = sock_sndtimeo(ssk, nonblock);
871 retry:
872 sk = netlink_getsockbypid(ssk, pid);
873 if (IS_ERR(sk)) {
874 kfree_skb(skb);
875 return PTR_ERR(sk);
876 }
877 if (netlink_is_kernel(sk))
878 return netlink_unicast_kernel(sk, skb);
879
880 err = netlink_attachskb(sk, skb, nonblock, timeo, ssk);
881 if (err == 1)
882 goto retry;
883 if (err)
884 return err;
885
886 return netlink_sendskb(sk, skb);
887 }
888
889 int netlink_has_listeners(struct sock *sk, unsigned int group)
890 {
891 int res = 0;
892 unsigned long *listeners;
893
894 BUG_ON(!netlink_is_kernel(sk));
895
896 rcu_read_lock();
897 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
898
899 if (group - 1 < nl_table[sk->sk_protocol].groups)
900 res = test_bit(group - 1, listeners);
901
902 rcu_read_unlock();
903
904 return res;
905 }
906 EXPORT_SYMBOL_GPL(netlink_has_listeners);
907
908 static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
909 {
910 struct netlink_sock *nlk = nlk_sk(sk);
911
912 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
913 !test_bit(0, &nlk->state)) {
914 skb_set_owner_r(skb, sk);
915 skb_queue_tail(&sk->sk_receive_queue, skb);
916 sk->sk_data_ready(sk, skb->len);
917 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
918 }
919 return -1;
920 }
921
922 struct netlink_broadcast_data {
923 struct sock *exclude_sk;
924 struct net *net;
925 u32 pid;
926 u32 group;
927 int failure;
928 int congested;
929 int delivered;
930 gfp_t allocation;
931 struct sk_buff *skb, *skb2;
932 };
933
934 static inline int do_one_broadcast(struct sock *sk,
935 struct netlink_broadcast_data *p)
936 {
937 struct netlink_sock *nlk = nlk_sk(sk);
938 int val;
939
940 if (p->exclude_sk == sk)
941 goto out;
942
943 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
944 !test_bit(p->group - 1, nlk->groups))
945 goto out;
946
947 if ((sk->sk_net != p->net))
948 goto out;
949
950 if (p->failure) {
951 netlink_overrun(sk);
952 goto out;
953 }
954
955 sock_hold(sk);
956 if (p->skb2 == NULL) {
957 if (skb_shared(p->skb)) {
958 p->skb2 = skb_clone(p->skb, p->allocation);
959 } else {
960 p->skb2 = skb_get(p->skb);
961 /*
962 * skb ownership may have been set when
963 * delivered to a previous socket.
964 */
965 skb_orphan(p->skb2);
966 }
967 }
968 if (p->skb2 == NULL) {
969 netlink_overrun(sk);
970 /* Clone failed. Notify ALL listeners. */
971 p->failure = 1;
972 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
973 netlink_overrun(sk);
974 } else {
975 p->congested |= val;
976 p->delivered = 1;
977 p->skb2 = NULL;
978 }
979 sock_put(sk);
980
981 out:
982 return 0;
983 }
984
985 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
986 u32 group, gfp_t allocation)
987 {
988 struct net *net = ssk->sk_net;
989 struct netlink_broadcast_data info;
990 struct hlist_node *node;
991 struct sock *sk;
992
993 skb = netlink_trim(skb, allocation);
994
995 info.exclude_sk = ssk;
996 info.net = net;
997 info.pid = pid;
998 info.group = group;
999 info.failure = 0;
1000 info.congested = 0;
1001 info.delivered = 0;
1002 info.allocation = allocation;
1003 info.skb = skb;
1004 info.skb2 = NULL;
1005
1006 /* While we sleep in clone, do not allow to change socket list */
1007
1008 netlink_lock_table();
1009
1010 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1011 do_one_broadcast(sk, &info);
1012
1013 kfree_skb(skb);
1014
1015 netlink_unlock_table();
1016
1017 if (info.skb2)
1018 kfree_skb(info.skb2);
1019
1020 if (info.delivered) {
1021 if (info.congested && (allocation & __GFP_WAIT))
1022 yield();
1023 return 0;
1024 }
1025 if (info.failure)
1026 return -ENOBUFS;
1027 return -ESRCH;
1028 }
1029
1030 struct netlink_set_err_data {
1031 struct sock *exclude_sk;
1032 u32 pid;
1033 u32 group;
1034 int code;
1035 };
1036
1037 static inline int do_one_set_err(struct sock *sk,
1038 struct netlink_set_err_data *p)
1039 {
1040 struct netlink_sock *nlk = nlk_sk(sk);
1041
1042 if (sk == p->exclude_sk)
1043 goto out;
1044
1045 if (sk->sk_net != p->exclude_sk->sk_net)
1046 goto out;
1047
1048 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1049 !test_bit(p->group - 1, nlk->groups))
1050 goto out;
1051
1052 sk->sk_err = p->code;
1053 sk->sk_error_report(sk);
1054 out:
1055 return 0;
1056 }
1057
1058 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1059 {
1060 struct netlink_set_err_data info;
1061 struct hlist_node *node;
1062 struct sock *sk;
1063
1064 info.exclude_sk = ssk;
1065 info.pid = pid;
1066 info.group = group;
1067 info.code = code;
1068
1069 read_lock(&nl_table_lock);
1070
1071 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1072 do_one_set_err(sk, &info);
1073
1074 read_unlock(&nl_table_lock);
1075 }
1076
1077 /* must be called with netlink table grabbed */
1078 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1079 unsigned int group,
1080 int is_new)
1081 {
1082 int old, new = !!is_new, subscriptions;
1083
1084 old = test_bit(group - 1, nlk->groups);
1085 subscriptions = nlk->subscriptions - old + new;
1086 if (new)
1087 __set_bit(group - 1, nlk->groups);
1088 else
1089 __clear_bit(group - 1, nlk->groups);
1090 netlink_update_subscriptions(&nlk->sk, subscriptions);
1091 netlink_update_listeners(&nlk->sk);
1092 }
1093
1094 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1095 char __user *optval, int optlen)
1096 {
1097 struct sock *sk = sock->sk;
1098 struct netlink_sock *nlk = nlk_sk(sk);
1099 unsigned int val = 0;
1100 int err;
1101
1102 if (level != SOL_NETLINK)
1103 return -ENOPROTOOPT;
1104
1105 if (optlen >= sizeof(int) &&
1106 get_user(val, (unsigned int __user *)optval))
1107 return -EFAULT;
1108
1109 switch (optname) {
1110 case NETLINK_PKTINFO:
1111 if (val)
1112 nlk->flags |= NETLINK_RECV_PKTINFO;
1113 else
1114 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1115 err = 0;
1116 break;
1117 case NETLINK_ADD_MEMBERSHIP:
1118 case NETLINK_DROP_MEMBERSHIP: {
1119 if (!netlink_capable(sock, NL_NONROOT_RECV))
1120 return -EPERM;
1121 err = netlink_realloc_groups(sk);
1122 if (err)
1123 return err;
1124 if (!val || val - 1 >= nlk->ngroups)
1125 return -EINVAL;
1126 netlink_table_grab();
1127 netlink_update_socket_mc(nlk, val,
1128 optname == NETLINK_ADD_MEMBERSHIP);
1129 netlink_table_ungrab();
1130 err = 0;
1131 break;
1132 }
1133 default:
1134 err = -ENOPROTOOPT;
1135 }
1136 return err;
1137 }
1138
1139 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1140 char __user *optval, int __user *optlen)
1141 {
1142 struct sock *sk = sock->sk;
1143 struct netlink_sock *nlk = nlk_sk(sk);
1144 int len, val, err;
1145
1146 if (level != SOL_NETLINK)
1147 return -ENOPROTOOPT;
1148
1149 if (get_user(len, optlen))
1150 return -EFAULT;
1151 if (len < 0)
1152 return -EINVAL;
1153
1154 switch (optname) {
1155 case NETLINK_PKTINFO:
1156 if (len < sizeof(int))
1157 return -EINVAL;
1158 len = sizeof(int);
1159 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1160 if (put_user(len, optlen) ||
1161 put_user(val, optval))
1162 return -EFAULT;
1163 err = 0;
1164 break;
1165 default:
1166 err = -ENOPROTOOPT;
1167 }
1168 return err;
1169 }
1170
1171 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1172 {
1173 struct nl_pktinfo info;
1174
1175 info.group = NETLINK_CB(skb).dst_group;
1176 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1177 }
1178
1179 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1180 struct msghdr *msg, size_t len)
1181 {
1182 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1183 struct sock *sk = sock->sk;
1184 struct netlink_sock *nlk = nlk_sk(sk);
1185 struct sockaddr_nl *addr=msg->msg_name;
1186 u32 dst_pid;
1187 u32 dst_group;
1188 struct sk_buff *skb;
1189 int err;
1190 struct scm_cookie scm;
1191
1192 if (msg->msg_flags&MSG_OOB)
1193 return -EOPNOTSUPP;
1194
1195 if (NULL == siocb->scm)
1196 siocb->scm = &scm;
1197 err = scm_send(sock, msg, siocb->scm);
1198 if (err < 0)
1199 return err;
1200
1201 if (msg->msg_namelen) {
1202 if (addr->nl_family != AF_NETLINK)
1203 return -EINVAL;
1204 dst_pid = addr->nl_pid;
1205 dst_group = ffs(addr->nl_groups);
1206 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1207 return -EPERM;
1208 } else {
1209 dst_pid = nlk->dst_pid;
1210 dst_group = nlk->dst_group;
1211 }
1212
1213 if (!nlk->pid) {
1214 err = netlink_autobind(sock);
1215 if (err)
1216 goto out;
1217 }
1218
1219 err = -EMSGSIZE;
1220 if (len > sk->sk_sndbuf - 32)
1221 goto out;
1222 err = -ENOBUFS;
1223 skb = alloc_skb(len, GFP_KERNEL);
1224 if (skb==NULL)
1225 goto out;
1226
1227 NETLINK_CB(skb).pid = nlk->pid;
1228 NETLINK_CB(skb).dst_group = dst_group;
1229 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
1230 selinux_get_task_sid(current, &(NETLINK_CB(skb).sid));
1231 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1232
1233 /* What can I do? Netlink is asynchronous, so that
1234 we will have to save current capabilities to
1235 check them, when this message will be delivered
1236 to corresponding kernel module. --ANK (980802)
1237 */
1238
1239 err = -EFAULT;
1240 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) {
1241 kfree_skb(skb);
1242 goto out;
1243 }
1244
1245 err = security_netlink_send(sk, skb);
1246 if (err) {
1247 kfree_skb(skb);
1248 goto out;
1249 }
1250
1251 if (dst_group) {
1252 atomic_inc(&skb->users);
1253 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1254 }
1255 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1256
1257 out:
1258 return err;
1259 }
1260
1261 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1262 struct msghdr *msg, size_t len,
1263 int flags)
1264 {
1265 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1266 struct scm_cookie scm;
1267 struct sock *sk = sock->sk;
1268 struct netlink_sock *nlk = nlk_sk(sk);
1269 int noblock = flags&MSG_DONTWAIT;
1270 size_t copied;
1271 struct sk_buff *skb;
1272 int err;
1273
1274 if (flags&MSG_OOB)
1275 return -EOPNOTSUPP;
1276
1277 copied = 0;
1278
1279 skb = skb_recv_datagram(sk,flags,noblock,&err);
1280 if (skb==NULL)
1281 goto out;
1282
1283 msg->msg_namelen = 0;
1284
1285 copied = skb->len;
1286 if (len < copied) {
1287 msg->msg_flags |= MSG_TRUNC;
1288 copied = len;
1289 }
1290
1291 skb_reset_transport_header(skb);
1292 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1293
1294 if (msg->msg_name) {
1295 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name;
1296 addr->nl_family = AF_NETLINK;
1297 addr->nl_pad = 0;
1298 addr->nl_pid = NETLINK_CB(skb).pid;
1299 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1300 msg->msg_namelen = sizeof(*addr);
1301 }
1302
1303 if (nlk->flags & NETLINK_RECV_PKTINFO)
1304 netlink_cmsg_recv_pktinfo(msg, skb);
1305
1306 if (NULL == siocb->scm) {
1307 memset(&scm, 0, sizeof(scm));
1308 siocb->scm = &scm;
1309 }
1310 siocb->scm->creds = *NETLINK_CREDS(skb);
1311 if (flags & MSG_TRUNC)
1312 copied = skb->len;
1313 skb_free_datagram(sk, skb);
1314
1315 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1316 netlink_dump(sk);
1317
1318 scm_recv(sock, msg, siocb->scm, flags);
1319 out:
1320 netlink_rcv_wake(sk);
1321 return err ? : copied;
1322 }
1323
1324 static void netlink_data_ready(struct sock *sk, int len)
1325 {
1326 BUG();
1327 }
1328
1329 /*
1330 * We export these functions to other modules. They provide a
1331 * complete set of kernel non-blocking support for message
1332 * queueing.
1333 */
1334
1335 struct sock *
1336 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1337 void (*input)(struct sk_buff *skb),
1338 struct mutex *cb_mutex, struct module *module)
1339 {
1340 struct socket *sock;
1341 struct sock *sk;
1342 struct netlink_sock *nlk;
1343 unsigned long *listeners = NULL;
1344
1345 BUG_ON(!nl_table);
1346
1347 if (unit<0 || unit>=MAX_LINKS)
1348 return NULL;
1349
1350 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1351 return NULL;
1352
1353 if (__netlink_create(net, sock, cb_mutex, unit) < 0)
1354 goto out_sock_release;
1355
1356 if (groups < 32)
1357 groups = 32;
1358
1359 listeners = kzalloc(NLGRPSZ(groups), GFP_KERNEL);
1360 if (!listeners)
1361 goto out_sock_release;
1362
1363 sk = sock->sk;
1364 sk->sk_data_ready = netlink_data_ready;
1365 if (input)
1366 nlk_sk(sk)->netlink_rcv = input;
1367
1368 if (netlink_insert(sk, net, 0))
1369 goto out_sock_release;
1370
1371 nlk = nlk_sk(sk);
1372 nlk->flags |= NETLINK_KERNEL_SOCKET;
1373
1374 netlink_table_grab();
1375 if (!nl_table[unit].registered) {
1376 nl_table[unit].groups = groups;
1377 nl_table[unit].listeners = listeners;
1378 nl_table[unit].cb_mutex = cb_mutex;
1379 nl_table[unit].module = module;
1380 nl_table[unit].registered = 1;
1381 }
1382 netlink_table_ungrab();
1383
1384 return sk;
1385
1386 out_sock_release:
1387 kfree(listeners);
1388 sock_release(sock);
1389 return NULL;
1390 }
1391
1392 /**
1393 * netlink_change_ngroups - change number of multicast groups
1394 *
1395 * This changes the number of multicast groups that are available
1396 * on a certain netlink family. Note that it is not possible to
1397 * change the number of groups to below 32. Also note that it does
1398 * not implicitly call netlink_clear_multicast_users() when the
1399 * number of groups is reduced.
1400 *
1401 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1402 * @groups: The new number of groups.
1403 */
1404 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1405 {
1406 unsigned long *listeners, *old = NULL;
1407 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1408 int err = 0;
1409
1410 if (groups < 32)
1411 groups = 32;
1412
1413 netlink_table_grab();
1414 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1415 listeners = kzalloc(NLGRPSZ(groups), GFP_ATOMIC);
1416 if (!listeners) {
1417 err = -ENOMEM;
1418 goto out_ungrab;
1419 }
1420 old = tbl->listeners;
1421 memcpy(listeners, old, NLGRPSZ(tbl->groups));
1422 rcu_assign_pointer(tbl->listeners, listeners);
1423 }
1424 tbl->groups = groups;
1425
1426 out_ungrab:
1427 netlink_table_ungrab();
1428 synchronize_rcu();
1429 kfree(old);
1430 return err;
1431 }
1432 EXPORT_SYMBOL(netlink_change_ngroups);
1433
1434 /**
1435 * netlink_clear_multicast_users - kick off multicast listeners
1436 *
1437 * This function removes all listeners from the given group.
1438 * @ksk: The kernel netlink socket, as returned by
1439 * netlink_kernel_create().
1440 * @group: The multicast group to clear.
1441 */
1442 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1443 {
1444 struct sock *sk;
1445 struct hlist_node *node;
1446 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1447
1448 netlink_table_grab();
1449
1450 sk_for_each_bound(sk, node, &tbl->mc_list)
1451 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1452
1453 netlink_table_ungrab();
1454 }
1455 EXPORT_SYMBOL(netlink_clear_multicast_users);
1456
1457 void netlink_set_nonroot(int protocol, unsigned int flags)
1458 {
1459 if ((unsigned int)protocol < MAX_LINKS)
1460 nl_table[protocol].nl_nonroot = flags;
1461 }
1462
1463 static void netlink_destroy_callback(struct netlink_callback *cb)
1464 {
1465 if (cb->skb)
1466 kfree_skb(cb->skb);
1467 kfree(cb);
1468 }
1469
1470 /*
1471 * It looks a bit ugly.
1472 * It would be better to create kernel thread.
1473 */
1474
1475 static int netlink_dump(struct sock *sk)
1476 {
1477 struct netlink_sock *nlk = nlk_sk(sk);
1478 struct netlink_callback *cb;
1479 struct sk_buff *skb;
1480 struct nlmsghdr *nlh;
1481 int len, err = -ENOBUFS;
1482
1483 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1484 if (!skb)
1485 goto errout;
1486
1487 mutex_lock(nlk->cb_mutex);
1488
1489 cb = nlk->cb;
1490 if (cb == NULL) {
1491 err = -EINVAL;
1492 goto errout_skb;
1493 }
1494
1495 len = cb->dump(skb, cb);
1496
1497 if (len > 0) {
1498 mutex_unlock(nlk->cb_mutex);
1499 skb_queue_tail(&sk->sk_receive_queue, skb);
1500 sk->sk_data_ready(sk, len);
1501 return 0;
1502 }
1503
1504 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1505 if (!nlh)
1506 goto errout_skb;
1507
1508 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1509
1510 skb_queue_tail(&sk->sk_receive_queue, skb);
1511 sk->sk_data_ready(sk, skb->len);
1512
1513 if (cb->done)
1514 cb->done(cb);
1515 nlk->cb = NULL;
1516 mutex_unlock(nlk->cb_mutex);
1517
1518 netlink_destroy_callback(cb);
1519 return 0;
1520
1521 errout_skb:
1522 mutex_unlock(nlk->cb_mutex);
1523 kfree_skb(skb);
1524 errout:
1525 return err;
1526 }
1527
1528 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1529 struct nlmsghdr *nlh,
1530 int (*dump)(struct sk_buff *skb, struct netlink_callback*),
1531 int (*done)(struct netlink_callback*))
1532 {
1533 struct netlink_callback *cb;
1534 struct sock *sk;
1535 struct netlink_sock *nlk;
1536
1537 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1538 if (cb == NULL)
1539 return -ENOBUFS;
1540
1541 cb->dump = dump;
1542 cb->done = done;
1543 cb->nlh = nlh;
1544 atomic_inc(&skb->users);
1545 cb->skb = skb;
1546
1547 sk = netlink_lookup(ssk->sk_net, ssk->sk_protocol, NETLINK_CB(skb).pid);
1548 if (sk == NULL) {
1549 netlink_destroy_callback(cb);
1550 return -ECONNREFUSED;
1551 }
1552 nlk = nlk_sk(sk);
1553 /* A dump is in progress... */
1554 mutex_lock(nlk->cb_mutex);
1555 if (nlk->cb) {
1556 mutex_unlock(nlk->cb_mutex);
1557 netlink_destroy_callback(cb);
1558 sock_put(sk);
1559 return -EBUSY;
1560 }
1561 nlk->cb = cb;
1562 mutex_unlock(nlk->cb_mutex);
1563
1564 netlink_dump(sk);
1565 sock_put(sk);
1566 return 0;
1567 }
1568
1569 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1570 {
1571 struct sk_buff *skb;
1572 struct nlmsghdr *rep;
1573 struct nlmsgerr *errmsg;
1574 size_t payload = sizeof(*errmsg);
1575
1576 /* error messages get the original request appened */
1577 if (err)
1578 payload += nlmsg_len(nlh);
1579
1580 skb = nlmsg_new(payload, GFP_KERNEL);
1581 if (!skb) {
1582 struct sock *sk;
1583
1584 sk = netlink_lookup(in_skb->sk->sk_net,
1585 in_skb->sk->sk_protocol,
1586 NETLINK_CB(in_skb).pid);
1587 if (sk) {
1588 sk->sk_err = ENOBUFS;
1589 sk->sk_error_report(sk);
1590 sock_put(sk);
1591 }
1592 return;
1593 }
1594
1595 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1596 NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
1597 errmsg = nlmsg_data(rep);
1598 errmsg->error = err;
1599 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1600 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1601 }
1602
1603 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1604 struct nlmsghdr *))
1605 {
1606 struct nlmsghdr *nlh;
1607 int err;
1608
1609 while (skb->len >= nlmsg_total_size(0)) {
1610 int msglen;
1611
1612 nlh = nlmsg_hdr(skb);
1613 err = 0;
1614
1615 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1616 return 0;
1617
1618 /* Only requests are handled by the kernel */
1619 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1620 goto skip;
1621
1622 /* Skip control messages */
1623 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1624 goto skip;
1625
1626 err = cb(skb, nlh);
1627 skip:
1628 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1629 netlink_ack(skb, nlh, err);
1630
1631 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1632 if (msglen > skb->len)
1633 msglen = skb->len;
1634 skb_pull(skb, msglen);
1635 }
1636
1637 return 0;
1638 }
1639
1640 /**
1641 * nlmsg_notify - send a notification netlink message
1642 * @sk: netlink socket to use
1643 * @skb: notification message
1644 * @pid: destination netlink pid for reports or 0
1645 * @group: destination multicast group or 0
1646 * @report: 1 to report back, 0 to disable
1647 * @flags: allocation flags
1648 */
1649 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1650 unsigned int group, int report, gfp_t flags)
1651 {
1652 int err = 0;
1653
1654 if (group) {
1655 int exclude_pid = 0;
1656
1657 if (report) {
1658 atomic_inc(&skb->users);
1659 exclude_pid = pid;
1660 }
1661
1662 /* errors reported via destination sk->sk_err */
1663 nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1664 }
1665
1666 if (report)
1667 err = nlmsg_unicast(sk, skb, pid);
1668
1669 return err;
1670 }
1671
1672 #ifdef CONFIG_PROC_FS
1673 struct nl_seq_iter {
1674 struct net *net;
1675 int link;
1676 int hash_idx;
1677 };
1678
1679 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1680 {
1681 struct nl_seq_iter *iter = seq->private;
1682 int i, j;
1683 struct sock *s;
1684 struct hlist_node *node;
1685 loff_t off = 0;
1686
1687 for (i=0; i<MAX_LINKS; i++) {
1688 struct nl_pid_hash *hash = &nl_table[i].hash;
1689
1690 for (j = 0; j <= hash->mask; j++) {
1691 sk_for_each(s, node, &hash->table[j]) {
1692 if (iter->net != s->sk_net)
1693 continue;
1694 if (off == pos) {
1695 iter->link = i;
1696 iter->hash_idx = j;
1697 return s;
1698 }
1699 ++off;
1700 }
1701 }
1702 }
1703 return NULL;
1704 }
1705
1706 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1707 {
1708 read_lock(&nl_table_lock);
1709 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1710 }
1711
1712 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1713 {
1714 struct sock *s;
1715 struct nl_seq_iter *iter;
1716 int i, j;
1717
1718 ++*pos;
1719
1720 if (v == SEQ_START_TOKEN)
1721 return netlink_seq_socket_idx(seq, 0);
1722
1723 iter = seq->private;
1724 s = v;
1725 do {
1726 s = sk_next(s);
1727 } while (s && (iter->net != s->sk_net));
1728 if (s)
1729 return s;
1730
1731 i = iter->link;
1732 j = iter->hash_idx + 1;
1733
1734 do {
1735 struct nl_pid_hash *hash = &nl_table[i].hash;
1736
1737 for (; j <= hash->mask; j++) {
1738 s = sk_head(&hash->table[j]);
1739 while (s && (iter->net != s->sk_net))
1740 s = sk_next(s);
1741 if (s) {
1742 iter->link = i;
1743 iter->hash_idx = j;
1744 return s;
1745 }
1746 }
1747
1748 j = 0;
1749 } while (++i < MAX_LINKS);
1750
1751 return NULL;
1752 }
1753
1754 static void netlink_seq_stop(struct seq_file *seq, void *v)
1755 {
1756 read_unlock(&nl_table_lock);
1757 }
1758
1759
1760 static int netlink_seq_show(struct seq_file *seq, void *v)
1761 {
1762 if (v == SEQ_START_TOKEN)
1763 seq_puts(seq,
1764 "sk Eth Pid Groups "
1765 "Rmem Wmem Dump Locks\n");
1766 else {
1767 struct sock *s = v;
1768 struct netlink_sock *nlk = nlk_sk(s);
1769
1770 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
1771 s,
1772 s->sk_protocol,
1773 nlk->pid,
1774 nlk->groups ? (u32)nlk->groups[0] : 0,
1775 atomic_read(&s->sk_rmem_alloc),
1776 atomic_read(&s->sk_wmem_alloc),
1777 nlk->cb,
1778 atomic_read(&s->sk_refcnt)
1779 );
1780
1781 }
1782 return 0;
1783 }
1784
1785 static const struct seq_operations netlink_seq_ops = {
1786 .start = netlink_seq_start,
1787 .next = netlink_seq_next,
1788 .stop = netlink_seq_stop,
1789 .show = netlink_seq_show,
1790 };
1791
1792
1793 static int netlink_seq_open(struct inode *inode, struct file *file)
1794 {
1795 struct nl_seq_iter *iter;
1796
1797 iter = __seq_open_private(file, &netlink_seq_ops, sizeof(*iter));
1798 if (!iter)
1799 return -ENOMEM;
1800
1801 iter->net = get_proc_net(inode);
1802 if (!iter->net) {
1803 seq_release_private(inode, file);
1804 return -ENXIO;
1805 }
1806
1807 return 0;
1808 }
1809
1810 static int netlink_seq_release(struct inode *inode, struct file *file)
1811 {
1812 struct seq_file *seq = file->private_data;
1813 struct nl_seq_iter *iter = seq->private;
1814 put_net(iter->net);
1815 return seq_release_private(inode, file);
1816 }
1817
1818 static const struct file_operations netlink_seq_fops = {
1819 .owner = THIS_MODULE,
1820 .open = netlink_seq_open,
1821 .read = seq_read,
1822 .llseek = seq_lseek,
1823 .release = netlink_seq_release,
1824 };
1825
1826 #endif
1827
1828 int netlink_register_notifier(struct notifier_block *nb)
1829 {
1830 return atomic_notifier_chain_register(&netlink_chain, nb);
1831 }
1832
1833 int netlink_unregister_notifier(struct notifier_block *nb)
1834 {
1835 return atomic_notifier_chain_unregister(&netlink_chain, nb);
1836 }
1837
1838 static const struct proto_ops netlink_ops = {
1839 .family = PF_NETLINK,
1840 .owner = THIS_MODULE,
1841 .release = netlink_release,
1842 .bind = netlink_bind,
1843 .connect = netlink_connect,
1844 .socketpair = sock_no_socketpair,
1845 .accept = sock_no_accept,
1846 .getname = netlink_getname,
1847 .poll = datagram_poll,
1848 .ioctl = sock_no_ioctl,
1849 .listen = sock_no_listen,
1850 .shutdown = sock_no_shutdown,
1851 .setsockopt = netlink_setsockopt,
1852 .getsockopt = netlink_getsockopt,
1853 .sendmsg = netlink_sendmsg,
1854 .recvmsg = netlink_recvmsg,
1855 .mmap = sock_no_mmap,
1856 .sendpage = sock_no_sendpage,
1857 };
1858
1859 static struct net_proto_family netlink_family_ops = {
1860 .family = PF_NETLINK,
1861 .create = netlink_create,
1862 .owner = THIS_MODULE, /* for consistency 8) */
1863 };
1864
1865 static int __net_init netlink_net_init(struct net *net)
1866 {
1867 #ifdef CONFIG_PROC_FS
1868 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
1869 return -ENOMEM;
1870 #endif
1871 return 0;
1872 }
1873
1874 static void __net_exit netlink_net_exit(struct net *net)
1875 {
1876 #ifdef CONFIG_PROC_FS
1877 proc_net_remove(net, "netlink");
1878 #endif
1879 }
1880
1881 static struct pernet_operations __net_initdata netlink_net_ops = {
1882 .init = netlink_net_init,
1883 .exit = netlink_net_exit,
1884 };
1885
1886 static int __init netlink_proto_init(void)
1887 {
1888 struct sk_buff *dummy_skb;
1889 int i;
1890 unsigned long limit;
1891 unsigned int order;
1892 int err = proto_register(&netlink_proto, 0);
1893
1894 if (err != 0)
1895 goto out;
1896
1897 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
1898
1899 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
1900 if (!nl_table)
1901 goto panic;
1902
1903 if (num_physpages >= (128 * 1024))
1904 limit = num_physpages >> (21 - PAGE_SHIFT);
1905 else
1906 limit = num_physpages >> (23 - PAGE_SHIFT);
1907
1908 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
1909 limit = (1UL << order) / sizeof(struct hlist_head);
1910 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
1911
1912 for (i = 0; i < MAX_LINKS; i++) {
1913 struct nl_pid_hash *hash = &nl_table[i].hash;
1914
1915 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table));
1916 if (!hash->table) {
1917 while (i-- > 0)
1918 nl_pid_hash_free(nl_table[i].hash.table,
1919 1 * sizeof(*hash->table));
1920 kfree(nl_table);
1921 goto panic;
1922 }
1923 memset(hash->table, 0, 1 * sizeof(*hash->table));
1924 hash->max_shift = order;
1925 hash->shift = 0;
1926 hash->mask = 0;
1927 hash->rehash_time = jiffies;
1928 }
1929
1930 sock_register(&netlink_family_ops);
1931 register_pernet_subsys(&netlink_net_ops);
1932 /* The netlink device handler may be needed early. */
1933 rtnetlink_init();
1934 out:
1935 return err;
1936 panic:
1937 panic("netlink_init: Cannot allocate nl_table\n");
1938 }
1939
1940 core_initcall(netlink_proto_init);
1941
1942 EXPORT_SYMBOL(netlink_ack);
1943 EXPORT_SYMBOL(netlink_rcv_skb);
1944 EXPORT_SYMBOL(netlink_broadcast);
1945 EXPORT_SYMBOL(netlink_dump_start);
1946 EXPORT_SYMBOL(netlink_kernel_create);
1947 EXPORT_SYMBOL(netlink_register_notifier);
1948 EXPORT_SYMBOL(netlink_set_nonroot);
1949 EXPORT_SYMBOL(netlink_unicast);
1950 EXPORT_SYMBOL(netlink_unregister_notifier);
1951 EXPORT_SYMBOL(nlmsg_notify);
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