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net/sysfs: Fix the bitrot in network device kobject namespace support
[mirror_ubuntu-artful-kernel.git] / net / netlink / af_netlink.c
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1/*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
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/mutex.h>
58
59#include <net/net_namespace.h>
60#include <net/sock.h>
61#include <net/scm.h>
62#include <net/netlink.h>
63
64#define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
65#define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long))
66
67struct netlink_sock {
68 /* struct sock has to be the first member of netlink_sock */
69 struct sock sk;
70 u32 pid;
71 u32 dst_pid;
72 u32 dst_group;
73 u32 flags;
74 u32 subscriptions;
75 u32 ngroups;
76 unsigned long *groups;
77 unsigned long state;
78 wait_queue_head_t wait;
79 struct netlink_callback *cb;
80 struct mutex *cb_mutex;
81 struct mutex cb_def_mutex;
82 void (*netlink_rcv)(struct sk_buff *skb);
83 struct module *module;
84};
85
86struct listeners_rcu_head {
87 struct rcu_head rcu_head;
88 void *ptr;
89};
90
91#define NETLINK_KERNEL_SOCKET 0x1
92#define NETLINK_RECV_PKTINFO 0x2
93#define NETLINK_BROADCAST_SEND_ERROR 0x4
94#define NETLINK_RECV_NO_ENOBUFS 0x8
95
96static inline struct netlink_sock *nlk_sk(struct sock *sk)
97{
98 return container_of(sk, struct netlink_sock, sk);
99}
100
101static inline int netlink_is_kernel(struct sock *sk)
102{
103 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
104}
105
106struct nl_pid_hash {
107 struct hlist_head *table;
108 unsigned long rehash_time;
109
110 unsigned int mask;
111 unsigned int shift;
112
113 unsigned int entries;
114 unsigned int max_shift;
115
116 u32 rnd;
117};
118
119struct netlink_table {
120 struct nl_pid_hash hash;
121 struct hlist_head mc_list;
122 unsigned long *listeners;
123 unsigned int nl_nonroot;
124 unsigned int groups;
125 struct mutex *cb_mutex;
126 struct module *module;
127 int registered;
128};
129
130static struct netlink_table *nl_table;
131
132static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
133
134static int netlink_dump(struct sock *sk);
135static void netlink_destroy_callback(struct netlink_callback *cb);
136
137static DEFINE_RWLOCK(nl_table_lock);
138static atomic_t nl_table_users = ATOMIC_INIT(0);
139
140static ATOMIC_NOTIFIER_HEAD(netlink_chain);
141
142static u32 netlink_group_mask(u32 group)
143{
144 return group ? 1 << (group - 1) : 0;
145}
146
147static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
148{
149 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
150}
151
152static void netlink_sock_destruct(struct sock *sk)
153{
154 struct netlink_sock *nlk = nlk_sk(sk);
155
156 if (nlk->cb) {
157 if (nlk->cb->done)
158 nlk->cb->done(nlk->cb);
159 netlink_destroy_callback(nlk->cb);
160 }
161
162 skb_queue_purge(&sk->sk_receive_queue);
163
164 if (!sock_flag(sk, SOCK_DEAD)) {
165 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
166 return;
167 }
168
169 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
170 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
171 WARN_ON(nlk_sk(sk)->groups);
172}
173
174/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
175 * SMP. Look, when several writers sleep and reader wakes them up, all but one
176 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
177 * this, _but_ remember, it adds useless work on UP machines.
178 */
179
180void netlink_table_grab(void)
181 __acquires(nl_table_lock)
182{
183 might_sleep();
184
185 write_lock_irq(&nl_table_lock);
186
187 if (atomic_read(&nl_table_users)) {
188 DECLARE_WAITQUEUE(wait, current);
189
190 add_wait_queue_exclusive(&nl_table_wait, &wait);
191 for (;;) {
192 set_current_state(TASK_UNINTERRUPTIBLE);
193 if (atomic_read(&nl_table_users) == 0)
194 break;
195 write_unlock_irq(&nl_table_lock);
196 schedule();
197 write_lock_irq(&nl_table_lock);
198 }
199
200 __set_current_state(TASK_RUNNING);
201 remove_wait_queue(&nl_table_wait, &wait);
202 }
203}
204
205void netlink_table_ungrab(void)
206 __releases(nl_table_lock)
207{
208 write_unlock_irq(&nl_table_lock);
209 wake_up(&nl_table_wait);
210}
211
212static inline void
213netlink_lock_table(void)
214{
215 /* read_lock() synchronizes us to netlink_table_grab */
216
217 read_lock(&nl_table_lock);
218 atomic_inc(&nl_table_users);
219 read_unlock(&nl_table_lock);
220}
221
222static inline void
223netlink_unlock_table(void)
224{
225 if (atomic_dec_and_test(&nl_table_users))
226 wake_up(&nl_table_wait);
227}
228
229static inline struct sock *netlink_lookup(struct net *net, int protocol,
230 u32 pid)
231{
232 struct nl_pid_hash *hash = &nl_table[protocol].hash;
233 struct hlist_head *head;
234 struct sock *sk;
235 struct hlist_node *node;
236
237 read_lock(&nl_table_lock);
238 head = nl_pid_hashfn(hash, pid);
239 sk_for_each(sk, node, head) {
240 if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) {
241 sock_hold(sk);
242 goto found;
243 }
244 }
245 sk = NULL;
246found:
247 read_unlock(&nl_table_lock);
248 return sk;
249}
250
251static inline struct hlist_head *nl_pid_hash_zalloc(size_t size)
252{
253 if (size <= PAGE_SIZE)
254 return kzalloc(size, GFP_ATOMIC);
255 else
256 return (struct hlist_head *)
257 __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
258 get_order(size));
259}
260
261static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
262{
263 if (size <= PAGE_SIZE)
264 kfree(table);
265 else
266 free_pages((unsigned long)table, get_order(size));
267}
268
269static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
270{
271 unsigned int omask, mask, shift;
272 size_t osize, size;
273 struct hlist_head *otable, *table;
274 int i;
275
276 omask = mask = hash->mask;
277 osize = size = (mask + 1) * sizeof(*table);
278 shift = hash->shift;
279
280 if (grow) {
281 if (++shift > hash->max_shift)
282 return 0;
283 mask = mask * 2 + 1;
284 size *= 2;
285 }
286
287 table = nl_pid_hash_zalloc(size);
288 if (!table)
289 return 0;
290
291 otable = hash->table;
292 hash->table = table;
293 hash->mask = mask;
294 hash->shift = shift;
295 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
296
297 for (i = 0; i <= omask; i++) {
298 struct sock *sk;
299 struct hlist_node *node, *tmp;
300
301 sk_for_each_safe(sk, node, tmp, &otable[i])
302 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
303 }
304
305 nl_pid_hash_free(otable, osize);
306 hash->rehash_time = jiffies + 10 * 60 * HZ;
307 return 1;
308}
309
310static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
311{
312 int avg = hash->entries >> hash->shift;
313
314 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
315 return 1;
316
317 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
318 nl_pid_hash_rehash(hash, 0);
319 return 1;
320 }
321
322 return 0;
323}
324
325static const struct proto_ops netlink_ops;
326
327static void
328netlink_update_listeners(struct sock *sk)
329{
330 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
331 struct hlist_node *node;
332 unsigned long mask;
333 unsigned int i;
334
335 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
336 mask = 0;
337 sk_for_each_bound(sk, node, &tbl->mc_list) {
338 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
339 mask |= nlk_sk(sk)->groups[i];
340 }
341 tbl->listeners[i] = mask;
342 }
343 /* this function is only called with the netlink table "grabbed", which
344 * makes sure updates are visible before bind or setsockopt return. */
345}
346
347static int netlink_insert(struct sock *sk, struct net *net, u32 pid)
348{
349 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
350 struct hlist_head *head;
351 int err = -EADDRINUSE;
352 struct sock *osk;
353 struct hlist_node *node;
354 int len;
355
356 netlink_table_grab();
357 head = nl_pid_hashfn(hash, pid);
358 len = 0;
359 sk_for_each(osk, node, head) {
360 if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->pid == pid))
361 break;
362 len++;
363 }
364 if (node)
365 goto err;
366
367 err = -EBUSY;
368 if (nlk_sk(sk)->pid)
369 goto err;
370
371 err = -ENOMEM;
372 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
373 goto err;
374
375 if (len && nl_pid_hash_dilute(hash, len))
376 head = nl_pid_hashfn(hash, pid);
377 hash->entries++;
378 nlk_sk(sk)->pid = pid;
379 sk_add_node(sk, head);
380 err = 0;
381
382err:
383 netlink_table_ungrab();
384 return err;
385}
386
387static void netlink_remove(struct sock *sk)
388{
389 netlink_table_grab();
390 if (sk_del_node_init(sk))
391 nl_table[sk->sk_protocol].hash.entries--;
392 if (nlk_sk(sk)->subscriptions)
393 __sk_del_bind_node(sk);
394 netlink_table_ungrab();
395}
396
397static struct proto netlink_proto = {
398 .name = "NETLINK",
399 .owner = THIS_MODULE,
400 .obj_size = sizeof(struct netlink_sock),
401};
402
403static int __netlink_create(struct net *net, struct socket *sock,
404 struct mutex *cb_mutex, int protocol)
405{
406 struct sock *sk;
407 struct netlink_sock *nlk;
408
409 sock->ops = &netlink_ops;
410
411 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
412 if (!sk)
413 return -ENOMEM;
414
415 sock_init_data(sock, sk);
416
417 nlk = nlk_sk(sk);
418 if (cb_mutex)
419 nlk->cb_mutex = cb_mutex;
420 else {
421 nlk->cb_mutex = &nlk->cb_def_mutex;
422 mutex_init(nlk->cb_mutex);
423 }
424 init_waitqueue_head(&nlk->wait);
425
426 sk->sk_destruct = netlink_sock_destruct;
427 sk->sk_protocol = protocol;
428 return 0;
429}
430
431static int netlink_create(struct net *net, struct socket *sock, int protocol,
432 int kern)
433{
434 struct module *module = NULL;
435 struct mutex *cb_mutex;
436 struct netlink_sock *nlk;
437 int err = 0;
438
439 sock->state = SS_UNCONNECTED;
440
441 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
442 return -ESOCKTNOSUPPORT;
443
444 if (protocol < 0 || protocol >= MAX_LINKS)
445 return -EPROTONOSUPPORT;
446
447 netlink_lock_table();
448#ifdef CONFIG_MODULES
449 if (!nl_table[protocol].registered) {
450 netlink_unlock_table();
451 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
452 netlink_lock_table();
453 }
454#endif
455 if (nl_table[protocol].registered &&
456 try_module_get(nl_table[protocol].module))
457 module = nl_table[protocol].module;
458 else
459 err = -EPROTONOSUPPORT;
460 cb_mutex = nl_table[protocol].cb_mutex;
461 netlink_unlock_table();
462
463 if (err < 0)
464 goto out;
465
466 err = __netlink_create(net, sock, cb_mutex, protocol);
467 if (err < 0)
468 goto out_module;
469
470 local_bh_disable();
471 sock_prot_inuse_add(net, &netlink_proto, 1);
472 local_bh_enable();
473
474 nlk = nlk_sk(sock->sk);
475 nlk->module = module;
476out:
477 return err;
478
479out_module:
480 module_put(module);
481 goto out;
482}
483
484static int netlink_release(struct socket *sock)
485{
486 struct sock *sk = sock->sk;
487 struct netlink_sock *nlk;
488
489 if (!sk)
490 return 0;
491
492 netlink_remove(sk);
493 sock_orphan(sk);
494 nlk = nlk_sk(sk);
495
496 /*
497 * OK. Socket is unlinked, any packets that arrive now
498 * will be purged.
499 */
500
501 sock->sk = NULL;
502 wake_up_interruptible_all(&nlk->wait);
503
504 skb_queue_purge(&sk->sk_write_queue);
505
506 if (nlk->pid) {
507 struct netlink_notify n = {
508 .net = sock_net(sk),
509 .protocol = sk->sk_protocol,
510 .pid = nlk->pid,
511 };
512 atomic_notifier_call_chain(&netlink_chain,
513 NETLINK_URELEASE, &n);
514 }
515
516 module_put(nlk->module);
517
518 netlink_table_grab();
519 if (netlink_is_kernel(sk)) {
520 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
521 if (--nl_table[sk->sk_protocol].registered == 0) {
522 kfree(nl_table[sk->sk_protocol].listeners);
523 nl_table[sk->sk_protocol].module = NULL;
524 nl_table[sk->sk_protocol].registered = 0;
525 }
526 } else if (nlk->subscriptions)
527 netlink_update_listeners(sk);
528 netlink_table_ungrab();
529
530 kfree(nlk->groups);
531 nlk->groups = NULL;
532
533 local_bh_disable();
534 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
535 local_bh_enable();
536 sock_put(sk);
537 return 0;
538}
539
540static int netlink_autobind(struct socket *sock)
541{
542 struct sock *sk = sock->sk;
543 struct net *net = sock_net(sk);
544 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
545 struct hlist_head *head;
546 struct sock *osk;
547 struct hlist_node *node;
548 s32 pid = task_tgid_vnr(current);
549 int err;
550 static s32 rover = -4097;
551
552retry:
553 cond_resched();
554 netlink_table_grab();
555 head = nl_pid_hashfn(hash, pid);
556 sk_for_each(osk, node, head) {
557 if (!net_eq(sock_net(osk), net))
558 continue;
559 if (nlk_sk(osk)->pid == pid) {
560 /* Bind collision, search negative pid values. */
561 pid = rover--;
562 if (rover > -4097)
563 rover = -4097;
564 netlink_table_ungrab();
565 goto retry;
566 }
567 }
568 netlink_table_ungrab();
569
570 err = netlink_insert(sk, net, pid);
571 if (err == -EADDRINUSE)
572 goto retry;
573
574 /* If 2 threads race to autobind, that is fine. */
575 if (err == -EBUSY)
576 err = 0;
577
578 return err;
579}
580
581static inline int netlink_capable(struct socket *sock, unsigned int flag)
582{
583 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
584 capable(CAP_NET_ADMIN);
585}
586
587static void
588netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
589{
590 struct netlink_sock *nlk = nlk_sk(sk);
591
592 if (nlk->subscriptions && !subscriptions)
593 __sk_del_bind_node(sk);
594 else if (!nlk->subscriptions && subscriptions)
595 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
596 nlk->subscriptions = subscriptions;
597}
598
599static int netlink_realloc_groups(struct sock *sk)
600{
601 struct netlink_sock *nlk = nlk_sk(sk);
602 unsigned int groups;
603 unsigned long *new_groups;
604 int err = 0;
605
606 netlink_table_grab();
607
608 groups = nl_table[sk->sk_protocol].groups;
609 if (!nl_table[sk->sk_protocol].registered) {
610 err = -ENOENT;
611 goto out_unlock;
612 }
613
614 if (nlk->ngroups >= groups)
615 goto out_unlock;
616
617 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
618 if (new_groups == NULL) {
619 err = -ENOMEM;
620 goto out_unlock;
621 }
622 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
623 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
624
625 nlk->groups = new_groups;
626 nlk->ngroups = groups;
627 out_unlock:
628 netlink_table_ungrab();
629 return err;
630}
631
632static int netlink_bind(struct socket *sock, struct sockaddr *addr,
633 int addr_len)
634{
635 struct sock *sk = sock->sk;
636 struct net *net = sock_net(sk);
637 struct netlink_sock *nlk = nlk_sk(sk);
638 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
639 int err;
640
641 if (nladdr->nl_family != AF_NETLINK)
642 return -EINVAL;
643
644 /* Only superuser is allowed to listen multicasts */
645 if (nladdr->nl_groups) {
646 if (!netlink_capable(sock, NL_NONROOT_RECV))
647 return -EPERM;
648 err = netlink_realloc_groups(sk);
649 if (err)
650 return err;
651 }
652
653 if (nlk->pid) {
654 if (nladdr->nl_pid != nlk->pid)
655 return -EINVAL;
656 } else {
657 err = nladdr->nl_pid ?
658 netlink_insert(sk, net, nladdr->nl_pid) :
659 netlink_autobind(sock);
660 if (err)
661 return err;
662 }
663
664 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
665 return 0;
666
667 netlink_table_grab();
668 netlink_update_subscriptions(sk, nlk->subscriptions +
669 hweight32(nladdr->nl_groups) -
670 hweight32(nlk->groups[0]));
671 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
672 netlink_update_listeners(sk);
673 netlink_table_ungrab();
674
675 return 0;
676}
677
678static int netlink_connect(struct socket *sock, struct sockaddr *addr,
679 int alen, int flags)
680{
681 int err = 0;
682 struct sock *sk = sock->sk;
683 struct netlink_sock *nlk = nlk_sk(sk);
684 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
685
686 if (alen < sizeof(addr->sa_family))
687 return -EINVAL;
688
689 if (addr->sa_family == AF_UNSPEC) {
690 sk->sk_state = NETLINK_UNCONNECTED;
691 nlk->dst_pid = 0;
692 nlk->dst_group = 0;
693 return 0;
694 }
695 if (addr->sa_family != AF_NETLINK)
696 return -EINVAL;
697
698 /* Only superuser is allowed to send multicasts */
699 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
700 return -EPERM;
701
702 if (!nlk->pid)
703 err = netlink_autobind(sock);
704
705 if (err == 0) {
706 sk->sk_state = NETLINK_CONNECTED;
707 nlk->dst_pid = nladdr->nl_pid;
708 nlk->dst_group = ffs(nladdr->nl_groups);
709 }
710
711 return err;
712}
713
714static int netlink_getname(struct socket *sock, struct sockaddr *addr,
715 int *addr_len, int peer)
716{
717 struct sock *sk = sock->sk;
718 struct netlink_sock *nlk = nlk_sk(sk);
719 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
720
721 nladdr->nl_family = AF_NETLINK;
722 nladdr->nl_pad = 0;
723 *addr_len = sizeof(*nladdr);
724
725 if (peer) {
726 nladdr->nl_pid = nlk->dst_pid;
727 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
728 } else {
729 nladdr->nl_pid = nlk->pid;
730 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
731 }
732 return 0;
733}
734
735static void netlink_overrun(struct sock *sk)
736{
737 struct netlink_sock *nlk = nlk_sk(sk);
738
739 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
740 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
741 sk->sk_err = ENOBUFS;
742 sk->sk_error_report(sk);
743 }
744 }
745 atomic_inc(&sk->sk_drops);
746}
747
748static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
749{
750 struct sock *sock;
751 struct netlink_sock *nlk;
752
753 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid);
754 if (!sock)
755 return ERR_PTR(-ECONNREFUSED);
756
757 /* Don't bother queuing skb if kernel socket has no input function */
758 nlk = nlk_sk(sock);
759 if (sock->sk_state == NETLINK_CONNECTED &&
760 nlk->dst_pid != nlk_sk(ssk)->pid) {
761 sock_put(sock);
762 return ERR_PTR(-ECONNREFUSED);
763 }
764 return sock;
765}
766
767struct sock *netlink_getsockbyfilp(struct file *filp)
768{
769 struct inode *inode = filp->f_path.dentry->d_inode;
770 struct sock *sock;
771
772 if (!S_ISSOCK(inode->i_mode))
773 return ERR_PTR(-ENOTSOCK);
774
775 sock = SOCKET_I(inode)->sk;
776 if (sock->sk_family != AF_NETLINK)
777 return ERR_PTR(-EINVAL);
778
779 sock_hold(sock);
780 return sock;
781}
782
783/*
784 * Attach a skb to a netlink socket.
785 * The caller must hold a reference to the destination socket. On error, the
786 * reference is dropped. The skb is not send to the destination, just all
787 * all error checks are performed and memory in the queue is reserved.
788 * Return values:
789 * < 0: error. skb freed, reference to sock dropped.
790 * 0: continue
791 * 1: repeat lookup - reference dropped while waiting for socket memory.
792 */
793int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
794 long *timeo, struct sock *ssk)
795{
796 struct netlink_sock *nlk;
797
798 nlk = nlk_sk(sk);
799
800 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
801 test_bit(0, &nlk->state)) {
802 DECLARE_WAITQUEUE(wait, current);
803 if (!*timeo) {
804 if (!ssk || netlink_is_kernel(ssk))
805 netlink_overrun(sk);
806 sock_put(sk);
807 kfree_skb(skb);
808 return -EAGAIN;
809 }
810
811 __set_current_state(TASK_INTERRUPTIBLE);
812 add_wait_queue(&nlk->wait, &wait);
813
814 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
815 test_bit(0, &nlk->state)) &&
816 !sock_flag(sk, SOCK_DEAD))
817 *timeo = schedule_timeout(*timeo);
818
819 __set_current_state(TASK_RUNNING);
820 remove_wait_queue(&nlk->wait, &wait);
821 sock_put(sk);
822
823 if (signal_pending(current)) {
824 kfree_skb(skb);
825 return sock_intr_errno(*timeo);
826 }
827 return 1;
828 }
829 skb_set_owner_r(skb, sk);
830 return 0;
831}
832
833int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
834{
835 int len = skb->len;
836
837 skb_queue_tail(&sk->sk_receive_queue, skb);
838 sk->sk_data_ready(sk, len);
839 sock_put(sk);
840 return len;
841}
842
843void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
844{
845 kfree_skb(skb);
846 sock_put(sk);
847}
848
849static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
850 gfp_t allocation)
851{
852 int delta;
853
854 skb_orphan(skb);
855
856 delta = skb->end - skb->tail;
857 if (delta * 2 < skb->truesize)
858 return skb;
859
860 if (skb_shared(skb)) {
861 struct sk_buff *nskb = skb_clone(skb, allocation);
862 if (!nskb)
863 return skb;
864 kfree_skb(skb);
865 skb = nskb;
866 }
867
868 if (!pskb_expand_head(skb, 0, -delta, allocation))
869 skb->truesize -= delta;
870
871 return skb;
872}
873
874static inline void netlink_rcv_wake(struct sock *sk)
875{
876 struct netlink_sock *nlk = nlk_sk(sk);
877
878 if (skb_queue_empty(&sk->sk_receive_queue))
879 clear_bit(0, &nlk->state);
880 if (!test_bit(0, &nlk->state))
881 wake_up_interruptible(&nlk->wait);
882}
883
884static inline int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb)
885{
886 int ret;
887 struct netlink_sock *nlk = nlk_sk(sk);
888
889 ret = -ECONNREFUSED;
890 if (nlk->netlink_rcv != NULL) {
891 ret = skb->len;
892 skb_set_owner_r(skb, sk);
893 nlk->netlink_rcv(skb);
894 }
895 kfree_skb(skb);
896 sock_put(sk);
897 return ret;
898}
899
900int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
901 u32 pid, int nonblock)
902{
903 struct sock *sk;
904 int err;
905 long timeo;
906
907 skb = netlink_trim(skb, gfp_any());
908
909 timeo = sock_sndtimeo(ssk, nonblock);
910retry:
911 sk = netlink_getsockbypid(ssk, pid);
912 if (IS_ERR(sk)) {
913 kfree_skb(skb);
914 return PTR_ERR(sk);
915 }
916 if (netlink_is_kernel(sk))
917 return netlink_unicast_kernel(sk, skb);
918
919 if (sk_filter(sk, skb)) {
920 err = skb->len;
921 kfree_skb(skb);
922 sock_put(sk);
923 return err;
924 }
925
926 err = netlink_attachskb(sk, skb, &timeo, ssk);
927 if (err == 1)
928 goto retry;
929 if (err)
930 return err;
931
932 return netlink_sendskb(sk, skb);
933}
934EXPORT_SYMBOL(netlink_unicast);
935
936int netlink_has_listeners(struct sock *sk, unsigned int group)
937{
938 int res = 0;
939 unsigned long *listeners;
940
941 BUG_ON(!netlink_is_kernel(sk));
942
943 rcu_read_lock();
944 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
945
946 if (group - 1 < nl_table[sk->sk_protocol].groups)
947 res = test_bit(group - 1, listeners);
948
949 rcu_read_unlock();
950
951 return res;
952}
953EXPORT_SYMBOL_GPL(netlink_has_listeners);
954
955static inline int netlink_broadcast_deliver(struct sock *sk,
956 struct sk_buff *skb)
957{
958 struct netlink_sock *nlk = nlk_sk(sk);
959
960 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
961 !test_bit(0, &nlk->state)) {
962 skb_set_owner_r(skb, sk);
963 skb_queue_tail(&sk->sk_receive_queue, skb);
964 sk->sk_data_ready(sk, skb->len);
965 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
966 }
967 return -1;
968}
969
970struct netlink_broadcast_data {
971 struct sock *exclude_sk;
972 struct net *net;
973 u32 pid;
974 u32 group;
975 int failure;
976 int delivery_failure;
977 int congested;
978 int delivered;
979 gfp_t allocation;
980 struct sk_buff *skb, *skb2;
981};
982
983static inline int do_one_broadcast(struct sock *sk,
984 struct netlink_broadcast_data *p)
985{
986 struct netlink_sock *nlk = nlk_sk(sk);
987 int val;
988
989 if (p->exclude_sk == sk)
990 goto out;
991
992 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
993 !test_bit(p->group - 1, nlk->groups))
994 goto out;
995
996 if (!net_eq(sock_net(sk), p->net))
997 goto out;
998
999 if (p->failure) {
1000 netlink_overrun(sk);
1001 goto out;
1002 }
1003
1004 sock_hold(sk);
1005 if (p->skb2 == NULL) {
1006 if (skb_shared(p->skb)) {
1007 p->skb2 = skb_clone(p->skb, p->allocation);
1008 } else {
1009 p->skb2 = skb_get(p->skb);
1010 /*
1011 * skb ownership may have been set when
1012 * delivered to a previous socket.
1013 */
1014 skb_orphan(p->skb2);
1015 }
1016 }
1017 if (p->skb2 == NULL) {
1018 netlink_overrun(sk);
1019 /* Clone failed. Notify ALL listeners. */
1020 p->failure = 1;
1021 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1022 p->delivery_failure = 1;
1023 } else if (sk_filter(sk, p->skb2)) {
1024 kfree_skb(p->skb2);
1025 p->skb2 = NULL;
1026 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1027 netlink_overrun(sk);
1028 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1029 p->delivery_failure = 1;
1030 } else {
1031 p->congested |= val;
1032 p->delivered = 1;
1033 p->skb2 = NULL;
1034 }
1035 sock_put(sk);
1036
1037out:
1038 return 0;
1039}
1040
1041int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
1042 u32 group, gfp_t allocation)
1043{
1044 struct net *net = sock_net(ssk);
1045 struct netlink_broadcast_data info;
1046 struct hlist_node *node;
1047 struct sock *sk;
1048
1049 skb = netlink_trim(skb, allocation);
1050
1051 info.exclude_sk = ssk;
1052 info.net = net;
1053 info.pid = pid;
1054 info.group = group;
1055 info.failure = 0;
1056 info.delivery_failure = 0;
1057 info.congested = 0;
1058 info.delivered = 0;
1059 info.allocation = allocation;
1060 info.skb = skb;
1061 info.skb2 = NULL;
1062
1063 /* While we sleep in clone, do not allow to change socket list */
1064
1065 netlink_lock_table();
1066
1067 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1068 do_one_broadcast(sk, &info);
1069
1070 kfree_skb(skb);
1071
1072 netlink_unlock_table();
1073
1074 kfree_skb(info.skb2);
1075
1076 if (info.delivery_failure)
1077 return -ENOBUFS;
1078
1079 if (info.delivered) {
1080 if (info.congested && (allocation & __GFP_WAIT))
1081 yield();
1082 return 0;
1083 }
1084 return -ESRCH;
1085}
1086EXPORT_SYMBOL(netlink_broadcast);
1087
1088struct netlink_set_err_data {
1089 struct sock *exclude_sk;
1090 u32 pid;
1091 u32 group;
1092 int code;
1093};
1094
1095static inline int do_one_set_err(struct sock *sk,
1096 struct netlink_set_err_data *p)
1097{
1098 struct netlink_sock *nlk = nlk_sk(sk);
1099 int ret = 0;
1100
1101 if (sk == p->exclude_sk)
1102 goto out;
1103
1104 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1105 goto out;
1106
1107 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1108 !test_bit(p->group - 1, nlk->groups))
1109 goto out;
1110
1111 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
1112 ret = 1;
1113 goto out;
1114 }
1115
1116 sk->sk_err = p->code;
1117 sk->sk_error_report(sk);
1118out:
1119 return ret;
1120}
1121
1122/**
1123 * netlink_set_err - report error to broadcast listeners
1124 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1125 * @pid: the PID of a process that we want to skip (if any)
1126 * @groups: the broadcast group that will notice the error
1127 * @code: error code, must be negative (as usual in kernelspace)
1128 *
1129 * This function returns the number of broadcast listeners that have set the
1130 * NETLINK_RECV_NO_ENOBUFS socket option.
1131 */
1132int netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1133{
1134 struct netlink_set_err_data info;
1135 struct hlist_node *node;
1136 struct sock *sk;
1137 int ret = 0;
1138
1139 info.exclude_sk = ssk;
1140 info.pid = pid;
1141 info.group = group;
1142 /* sk->sk_err wants a positive error value */
1143 info.code = -code;
1144
1145 read_lock(&nl_table_lock);
1146
1147 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1148 ret += do_one_set_err(sk, &info);
1149
1150 read_unlock(&nl_table_lock);
1151 return ret;
1152}
1153EXPORT_SYMBOL(netlink_set_err);
1154
1155/* must be called with netlink table grabbed */
1156static void netlink_update_socket_mc(struct netlink_sock *nlk,
1157 unsigned int group,
1158 int is_new)
1159{
1160 int old, new = !!is_new, subscriptions;
1161
1162 old = test_bit(group - 1, nlk->groups);
1163 subscriptions = nlk->subscriptions - old + new;
1164 if (new)
1165 __set_bit(group - 1, nlk->groups);
1166 else
1167 __clear_bit(group - 1, nlk->groups);
1168 netlink_update_subscriptions(&nlk->sk, subscriptions);
1169 netlink_update_listeners(&nlk->sk);
1170}
1171
1172static int netlink_setsockopt(struct socket *sock, int level, int optname,
1173 char __user *optval, unsigned int optlen)
1174{
1175 struct sock *sk = sock->sk;
1176 struct netlink_sock *nlk = nlk_sk(sk);
1177 unsigned int val = 0;
1178 int err;
1179
1180 if (level != SOL_NETLINK)
1181 return -ENOPROTOOPT;
1182
1183 if (optlen >= sizeof(int) &&
1184 get_user(val, (unsigned int __user *)optval))
1185 return -EFAULT;
1186
1187 switch (optname) {
1188 case NETLINK_PKTINFO:
1189 if (val)
1190 nlk->flags |= NETLINK_RECV_PKTINFO;
1191 else
1192 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1193 err = 0;
1194 break;
1195 case NETLINK_ADD_MEMBERSHIP:
1196 case NETLINK_DROP_MEMBERSHIP: {
1197 if (!netlink_capable(sock, NL_NONROOT_RECV))
1198 return -EPERM;
1199 err = netlink_realloc_groups(sk);
1200 if (err)
1201 return err;
1202 if (!val || val - 1 >= nlk->ngroups)
1203 return -EINVAL;
1204 netlink_table_grab();
1205 netlink_update_socket_mc(nlk, val,
1206 optname == NETLINK_ADD_MEMBERSHIP);
1207 netlink_table_ungrab();
1208 err = 0;
1209 break;
1210 }
1211 case NETLINK_BROADCAST_ERROR:
1212 if (val)
1213 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1214 else
1215 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1216 err = 0;
1217 break;
1218 case NETLINK_NO_ENOBUFS:
1219 if (val) {
1220 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1221 clear_bit(0, &nlk->state);
1222 wake_up_interruptible(&nlk->wait);
1223 } else
1224 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1225 err = 0;
1226 break;
1227 default:
1228 err = -ENOPROTOOPT;
1229 }
1230 return err;
1231}
1232
1233static int netlink_getsockopt(struct socket *sock, int level, int optname,
1234 char __user *optval, int __user *optlen)
1235{
1236 struct sock *sk = sock->sk;
1237 struct netlink_sock *nlk = nlk_sk(sk);
1238 int len, val, err;
1239
1240 if (level != SOL_NETLINK)
1241 return -ENOPROTOOPT;
1242
1243 if (get_user(len, optlen))
1244 return -EFAULT;
1245 if (len < 0)
1246 return -EINVAL;
1247
1248 switch (optname) {
1249 case NETLINK_PKTINFO:
1250 if (len < sizeof(int))
1251 return -EINVAL;
1252 len = sizeof(int);
1253 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1254 if (put_user(len, optlen) ||
1255 put_user(val, optval))
1256 return -EFAULT;
1257 err = 0;
1258 break;
1259 case NETLINK_BROADCAST_ERROR:
1260 if (len < sizeof(int))
1261 return -EINVAL;
1262 len = sizeof(int);
1263 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1264 if (put_user(len, optlen) ||
1265 put_user(val, optval))
1266 return -EFAULT;
1267 err = 0;
1268 break;
1269 case NETLINK_NO_ENOBUFS:
1270 if (len < sizeof(int))
1271 return -EINVAL;
1272 len = sizeof(int);
1273 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1274 if (put_user(len, optlen) ||
1275 put_user(val, optval))
1276 return -EFAULT;
1277 err = 0;
1278 break;
1279 default:
1280 err = -ENOPROTOOPT;
1281 }
1282 return err;
1283}
1284
1285static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1286{
1287 struct nl_pktinfo info;
1288
1289 info.group = NETLINK_CB(skb).dst_group;
1290 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1291}
1292
1293static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1294 struct msghdr *msg, size_t len)
1295{
1296 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1297 struct sock *sk = sock->sk;
1298 struct netlink_sock *nlk = nlk_sk(sk);
1299 struct sockaddr_nl *addr = msg->msg_name;
1300 u32 dst_pid;
1301 u32 dst_group;
1302 struct sk_buff *skb;
1303 int err;
1304 struct scm_cookie scm;
1305
1306 if (msg->msg_flags&MSG_OOB)
1307 return -EOPNOTSUPP;
1308
1309 if (NULL == siocb->scm)
1310 siocb->scm = &scm;
1311 err = scm_send(sock, msg, siocb->scm);
1312 if (err < 0)
1313 return err;
1314
1315 if (msg->msg_namelen) {
1316 if (addr->nl_family != AF_NETLINK)
1317 return -EINVAL;
1318 dst_pid = addr->nl_pid;
1319 dst_group = ffs(addr->nl_groups);
1320 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1321 return -EPERM;
1322 } else {
1323 dst_pid = nlk->dst_pid;
1324 dst_group = nlk->dst_group;
1325 }
1326
1327 if (!nlk->pid) {
1328 err = netlink_autobind(sock);
1329 if (err)
1330 goto out;
1331 }
1332
1333 err = -EMSGSIZE;
1334 if (len > sk->sk_sndbuf - 32)
1335 goto out;
1336 err = -ENOBUFS;
1337 skb = alloc_skb(len, GFP_KERNEL);
1338 if (skb == NULL)
1339 goto out;
1340
1341 NETLINK_CB(skb).pid = nlk->pid;
1342 NETLINK_CB(skb).dst_group = dst_group;
1343 NETLINK_CB(skb).loginuid = audit_get_loginuid(current);
1344 NETLINK_CB(skb).sessionid = audit_get_sessionid(current);
1345 security_task_getsecid(current, &(NETLINK_CB(skb).sid));
1346 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1347
1348 /* What can I do? Netlink is asynchronous, so that
1349 we will have to save current capabilities to
1350 check them, when this message will be delivered
1351 to corresponding kernel module. --ANK (980802)
1352 */
1353
1354 err = -EFAULT;
1355 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1356 kfree_skb(skb);
1357 goto out;
1358 }
1359
1360 err = security_netlink_send(sk, skb);
1361 if (err) {
1362 kfree_skb(skb);
1363 goto out;
1364 }
1365
1366 if (dst_group) {
1367 atomic_inc(&skb->users);
1368 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1369 }
1370 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1371
1372out:
1373 return err;
1374}
1375
1376static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1377 struct msghdr *msg, size_t len,
1378 int flags)
1379{
1380 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1381 struct scm_cookie scm;
1382 struct sock *sk = sock->sk;
1383 struct netlink_sock *nlk = nlk_sk(sk);
1384 int noblock = flags&MSG_DONTWAIT;
1385 size_t copied;
1386 struct sk_buff *skb, *frag __maybe_unused = NULL;
1387 int err;
1388
1389 if (flags&MSG_OOB)
1390 return -EOPNOTSUPP;
1391
1392 copied = 0;
1393
1394 skb = skb_recv_datagram(sk, flags, noblock, &err);
1395 if (skb == NULL)
1396 goto out;
1397
1398#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1399 if (unlikely(skb_shinfo(skb)->frag_list)) {
1400 bool need_compat = !!(flags & MSG_CMSG_COMPAT);
1401
1402 /*
1403 * If this skb has a frag_list, then here that means that
1404 * we will have to use the frag_list skb for compat tasks
1405 * and the regular skb for non-compat tasks.
1406 *
1407 * The skb might (and likely will) be cloned, so we can't
1408 * just reset frag_list and go on with things -- we need to
1409 * keep that. For the compat case that's easy -- simply get
1410 * a reference to the compat skb and free the regular one
1411 * including the frag. For the non-compat case, we need to
1412 * avoid sending the frag to the user -- so assign NULL but
1413 * restore it below before freeing the skb.
1414 */
1415 if (need_compat) {
1416 struct sk_buff *compskb = skb_shinfo(skb)->frag_list;
1417 skb_get(compskb);
1418 kfree_skb(skb);
1419 skb = compskb;
1420 } else {
1421 frag = skb_shinfo(skb)->frag_list;
1422 skb_shinfo(skb)->frag_list = NULL;
1423 }
1424 }
1425#endif
1426
1427 msg->msg_namelen = 0;
1428
1429 copied = skb->len;
1430 if (len < copied) {
1431 msg->msg_flags |= MSG_TRUNC;
1432 copied = len;
1433 }
1434
1435 skb_reset_transport_header(skb);
1436 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1437
1438 if (msg->msg_name) {
1439 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1440 addr->nl_family = AF_NETLINK;
1441 addr->nl_pad = 0;
1442 addr->nl_pid = NETLINK_CB(skb).pid;
1443 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1444 msg->msg_namelen = sizeof(*addr);
1445 }
1446
1447 if (nlk->flags & NETLINK_RECV_PKTINFO)
1448 netlink_cmsg_recv_pktinfo(msg, skb);
1449
1450 if (NULL == siocb->scm) {
1451 memset(&scm, 0, sizeof(scm));
1452 siocb->scm = &scm;
1453 }
1454 siocb->scm->creds = *NETLINK_CREDS(skb);
1455 if (flags & MSG_TRUNC)
1456 copied = skb->len;
1457
1458#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1459 skb_shinfo(skb)->frag_list = frag;
1460#endif
1461
1462 skb_free_datagram(sk, skb);
1463
1464 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1465 netlink_dump(sk);
1466
1467 scm_recv(sock, msg, siocb->scm, flags);
1468out:
1469 netlink_rcv_wake(sk);
1470 return err ? : copied;
1471}
1472
1473static void netlink_data_ready(struct sock *sk, int len)
1474{
1475 BUG();
1476}
1477
1478/*
1479 * We export these functions to other modules. They provide a
1480 * complete set of kernel non-blocking support for message
1481 * queueing.
1482 */
1483
1484struct sock *
1485netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1486 void (*input)(struct sk_buff *skb),
1487 struct mutex *cb_mutex, struct module *module)
1488{
1489 struct socket *sock;
1490 struct sock *sk;
1491 struct netlink_sock *nlk;
1492 unsigned long *listeners = NULL;
1493
1494 BUG_ON(!nl_table);
1495
1496 if (unit < 0 || unit >= MAX_LINKS)
1497 return NULL;
1498
1499 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1500 return NULL;
1501
1502 /*
1503 * We have to just have a reference on the net from sk, but don't
1504 * get_net it. Besides, we cannot get and then put the net here.
1505 * So we create one inside init_net and the move it to net.
1506 */
1507
1508 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1509 goto out_sock_release_nosk;
1510
1511 sk = sock->sk;
1512 sk_change_net(sk, net);
1513
1514 if (groups < 32)
1515 groups = 32;
1516
1517 listeners = kzalloc(NLGRPSZ(groups) + sizeof(struct listeners_rcu_head),
1518 GFP_KERNEL);
1519 if (!listeners)
1520 goto out_sock_release;
1521
1522 sk->sk_data_ready = netlink_data_ready;
1523 if (input)
1524 nlk_sk(sk)->netlink_rcv = input;
1525
1526 if (netlink_insert(sk, net, 0))
1527 goto out_sock_release;
1528
1529 nlk = nlk_sk(sk);
1530 nlk->flags |= NETLINK_KERNEL_SOCKET;
1531
1532 netlink_table_grab();
1533 if (!nl_table[unit].registered) {
1534 nl_table[unit].groups = groups;
1535 nl_table[unit].listeners = listeners;
1536 nl_table[unit].cb_mutex = cb_mutex;
1537 nl_table[unit].module = module;
1538 nl_table[unit].registered = 1;
1539 } else {
1540 kfree(listeners);
1541 nl_table[unit].registered++;
1542 }
1543 netlink_table_ungrab();
1544 return sk;
1545
1546out_sock_release:
1547 kfree(listeners);
1548 netlink_kernel_release(sk);
1549 return NULL;
1550
1551out_sock_release_nosk:
1552 sock_release(sock);
1553 return NULL;
1554}
1555EXPORT_SYMBOL(netlink_kernel_create);
1556
1557
1558void
1559netlink_kernel_release(struct sock *sk)
1560{
1561 sk_release_kernel(sk);
1562}
1563EXPORT_SYMBOL(netlink_kernel_release);
1564
1565
1566static void netlink_free_old_listeners(struct rcu_head *rcu_head)
1567{
1568 struct listeners_rcu_head *lrh;
1569
1570 lrh = container_of(rcu_head, struct listeners_rcu_head, rcu_head);
1571 kfree(lrh->ptr);
1572}
1573
1574int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1575{
1576 unsigned long *listeners, *old = NULL;
1577 struct listeners_rcu_head *old_rcu_head;
1578 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1579
1580 if (groups < 32)
1581 groups = 32;
1582
1583 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1584 listeners = kzalloc(NLGRPSZ(groups) +
1585 sizeof(struct listeners_rcu_head),
1586 GFP_ATOMIC);
1587 if (!listeners)
1588 return -ENOMEM;
1589 old = tbl->listeners;
1590 memcpy(listeners, old, NLGRPSZ(tbl->groups));
1591 rcu_assign_pointer(tbl->listeners, listeners);
1592 /*
1593 * Free the old memory after an RCU grace period so we
1594 * don't leak it. We use call_rcu() here in order to be
1595 * able to call this function from atomic contexts. The
1596 * allocation of this memory will have reserved enough
1597 * space for struct listeners_rcu_head at the end.
1598 */
1599 old_rcu_head = (void *)(tbl->listeners +
1600 NLGRPLONGS(tbl->groups));
1601 old_rcu_head->ptr = old;
1602 call_rcu(&old_rcu_head->rcu_head, netlink_free_old_listeners);
1603 }
1604 tbl->groups = groups;
1605
1606 return 0;
1607}
1608
1609/**
1610 * netlink_change_ngroups - change number of multicast groups
1611 *
1612 * This changes the number of multicast groups that are available
1613 * on a certain netlink family. Note that it is not possible to
1614 * change the number of groups to below 32. Also note that it does
1615 * not implicitly call netlink_clear_multicast_users() when the
1616 * number of groups is reduced.
1617 *
1618 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1619 * @groups: The new number of groups.
1620 */
1621int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1622{
1623 int err;
1624
1625 netlink_table_grab();
1626 err = __netlink_change_ngroups(sk, groups);
1627 netlink_table_ungrab();
1628
1629 return err;
1630}
1631
1632void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1633{
1634 struct sock *sk;
1635 struct hlist_node *node;
1636 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1637
1638 sk_for_each_bound(sk, node, &tbl->mc_list)
1639 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1640}
1641
1642/**
1643 * netlink_clear_multicast_users - kick off multicast listeners
1644 *
1645 * This function removes all listeners from the given group.
1646 * @ksk: The kernel netlink socket, as returned by
1647 * netlink_kernel_create().
1648 * @group: The multicast group to clear.
1649 */
1650void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1651{
1652 netlink_table_grab();
1653 __netlink_clear_multicast_users(ksk, group);
1654 netlink_table_ungrab();
1655}
1656
1657void netlink_set_nonroot(int protocol, unsigned int flags)
1658{
1659 if ((unsigned int)protocol < MAX_LINKS)
1660 nl_table[protocol].nl_nonroot = flags;
1661}
1662EXPORT_SYMBOL(netlink_set_nonroot);
1663
1664static void netlink_destroy_callback(struct netlink_callback *cb)
1665{
1666 kfree_skb(cb->skb);
1667 kfree(cb);
1668}
1669
1670/*
1671 * It looks a bit ugly.
1672 * It would be better to create kernel thread.
1673 */
1674
1675static int netlink_dump(struct sock *sk)
1676{
1677 struct netlink_sock *nlk = nlk_sk(sk);
1678 struct netlink_callback *cb;
1679 struct sk_buff *skb;
1680 struct nlmsghdr *nlh;
1681 int len, err = -ENOBUFS;
1682
1683 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1684 if (!skb)
1685 goto errout;
1686
1687 mutex_lock(nlk->cb_mutex);
1688
1689 cb = nlk->cb;
1690 if (cb == NULL) {
1691 err = -EINVAL;
1692 goto errout_skb;
1693 }
1694
1695 len = cb->dump(skb, cb);
1696
1697 if (len > 0) {
1698 mutex_unlock(nlk->cb_mutex);
1699
1700 if (sk_filter(sk, skb))
1701 kfree_skb(skb);
1702 else {
1703 skb_queue_tail(&sk->sk_receive_queue, skb);
1704 sk->sk_data_ready(sk, skb->len);
1705 }
1706 return 0;
1707 }
1708
1709 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1710 if (!nlh)
1711 goto errout_skb;
1712
1713 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1714
1715 if (sk_filter(sk, skb))
1716 kfree_skb(skb);
1717 else {
1718 skb_queue_tail(&sk->sk_receive_queue, skb);
1719 sk->sk_data_ready(sk, skb->len);
1720 }
1721
1722 if (cb->done)
1723 cb->done(cb);
1724 nlk->cb = NULL;
1725 mutex_unlock(nlk->cb_mutex);
1726
1727 netlink_destroy_callback(cb);
1728 return 0;
1729
1730errout_skb:
1731 mutex_unlock(nlk->cb_mutex);
1732 kfree_skb(skb);
1733errout:
1734 return err;
1735}
1736
1737int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1738 const struct nlmsghdr *nlh,
1739 int (*dump)(struct sk_buff *skb,
1740 struct netlink_callback *),
1741 int (*done)(struct netlink_callback *))
1742{
1743 struct netlink_callback *cb;
1744 struct sock *sk;
1745 struct netlink_sock *nlk;
1746
1747 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1748 if (cb == NULL)
1749 return -ENOBUFS;
1750
1751 cb->dump = dump;
1752 cb->done = done;
1753 cb->nlh = nlh;
1754 atomic_inc(&skb->users);
1755 cb->skb = skb;
1756
1757 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1758 if (sk == NULL) {
1759 netlink_destroy_callback(cb);
1760 return -ECONNREFUSED;
1761 }
1762 nlk = nlk_sk(sk);
1763 /* A dump is in progress... */
1764 mutex_lock(nlk->cb_mutex);
1765 if (nlk->cb) {
1766 mutex_unlock(nlk->cb_mutex);
1767 netlink_destroy_callback(cb);
1768 sock_put(sk);
1769 return -EBUSY;
1770 }
1771 nlk->cb = cb;
1772 mutex_unlock(nlk->cb_mutex);
1773
1774 netlink_dump(sk);
1775 sock_put(sk);
1776
1777 /* We successfully started a dump, by returning -EINTR we
1778 * signal not to send ACK even if it was requested.
1779 */
1780 return -EINTR;
1781}
1782EXPORT_SYMBOL(netlink_dump_start);
1783
1784void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1785{
1786 struct sk_buff *skb;
1787 struct nlmsghdr *rep;
1788 struct nlmsgerr *errmsg;
1789 size_t payload = sizeof(*errmsg);
1790
1791 /* error messages get the original request appened */
1792 if (err)
1793 payload += nlmsg_len(nlh);
1794
1795 skb = nlmsg_new(payload, GFP_KERNEL);
1796 if (!skb) {
1797 struct sock *sk;
1798
1799 sk = netlink_lookup(sock_net(in_skb->sk),
1800 in_skb->sk->sk_protocol,
1801 NETLINK_CB(in_skb).pid);
1802 if (sk) {
1803 sk->sk_err = ENOBUFS;
1804 sk->sk_error_report(sk);
1805 sock_put(sk);
1806 }
1807 return;
1808 }
1809
1810 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1811 NLMSG_ERROR, payload, 0);
1812 errmsg = nlmsg_data(rep);
1813 errmsg->error = err;
1814 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1815 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1816}
1817EXPORT_SYMBOL(netlink_ack);
1818
1819int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1820 struct nlmsghdr *))
1821{
1822 struct nlmsghdr *nlh;
1823 int err;
1824
1825 while (skb->len >= nlmsg_total_size(0)) {
1826 int msglen;
1827
1828 nlh = nlmsg_hdr(skb);
1829 err = 0;
1830
1831 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1832 return 0;
1833
1834 /* Only requests are handled by the kernel */
1835 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1836 goto ack;
1837
1838 /* Skip control messages */
1839 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1840 goto ack;
1841
1842 err = cb(skb, nlh);
1843 if (err == -EINTR)
1844 goto skip;
1845
1846ack:
1847 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1848 netlink_ack(skb, nlh, err);
1849
1850skip:
1851 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1852 if (msglen > skb->len)
1853 msglen = skb->len;
1854 skb_pull(skb, msglen);
1855 }
1856
1857 return 0;
1858}
1859EXPORT_SYMBOL(netlink_rcv_skb);
1860
1861/**
1862 * nlmsg_notify - send a notification netlink message
1863 * @sk: netlink socket to use
1864 * @skb: notification message
1865 * @pid: destination netlink pid for reports or 0
1866 * @group: destination multicast group or 0
1867 * @report: 1 to report back, 0 to disable
1868 * @flags: allocation flags
1869 */
1870int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1871 unsigned int group, int report, gfp_t flags)
1872{
1873 int err = 0;
1874
1875 if (group) {
1876 int exclude_pid = 0;
1877
1878 if (report) {
1879 atomic_inc(&skb->users);
1880 exclude_pid = pid;
1881 }
1882
1883 /* errors reported via destination sk->sk_err, but propagate
1884 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1885 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1886 }
1887
1888 if (report) {
1889 int err2;
1890
1891 err2 = nlmsg_unicast(sk, skb, pid);
1892 if (!err || err == -ESRCH)
1893 err = err2;
1894 }
1895
1896 return err;
1897}
1898EXPORT_SYMBOL(nlmsg_notify);
1899
1900#ifdef CONFIG_PROC_FS
1901struct nl_seq_iter {
1902 struct seq_net_private p;
1903 int link;
1904 int hash_idx;
1905};
1906
1907static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1908{
1909 struct nl_seq_iter *iter = seq->private;
1910 int i, j;
1911 struct sock *s;
1912 struct hlist_node *node;
1913 loff_t off = 0;
1914
1915 for (i = 0; i < MAX_LINKS; i++) {
1916 struct nl_pid_hash *hash = &nl_table[i].hash;
1917
1918 for (j = 0; j <= hash->mask; j++) {
1919 sk_for_each(s, node, &hash->table[j]) {
1920 if (sock_net(s) != seq_file_net(seq))
1921 continue;
1922 if (off == pos) {
1923 iter->link = i;
1924 iter->hash_idx = j;
1925 return s;
1926 }
1927 ++off;
1928 }
1929 }
1930 }
1931 return NULL;
1932}
1933
1934static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1935 __acquires(nl_table_lock)
1936{
1937 read_lock(&nl_table_lock);
1938 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1939}
1940
1941static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1942{
1943 struct sock *s;
1944 struct nl_seq_iter *iter;
1945 int i, j;
1946
1947 ++*pos;
1948
1949 if (v == SEQ_START_TOKEN)
1950 return netlink_seq_socket_idx(seq, 0);
1951
1952 iter = seq->private;
1953 s = v;
1954 do {
1955 s = sk_next(s);
1956 } while (s && sock_net(s) != seq_file_net(seq));
1957 if (s)
1958 return s;
1959
1960 i = iter->link;
1961 j = iter->hash_idx + 1;
1962
1963 do {
1964 struct nl_pid_hash *hash = &nl_table[i].hash;
1965
1966 for (; j <= hash->mask; j++) {
1967 s = sk_head(&hash->table[j]);
1968 while (s && sock_net(s) != seq_file_net(seq))
1969 s = sk_next(s);
1970 if (s) {
1971 iter->link = i;
1972 iter->hash_idx = j;
1973 return s;
1974 }
1975 }
1976
1977 j = 0;
1978 } while (++i < MAX_LINKS);
1979
1980 return NULL;
1981}
1982
1983static void netlink_seq_stop(struct seq_file *seq, void *v)
1984 __releases(nl_table_lock)
1985{
1986 read_unlock(&nl_table_lock);
1987}
1988
1989
1990static int netlink_seq_show(struct seq_file *seq, void *v)
1991{
1992 if (v == SEQ_START_TOKEN)
1993 seq_puts(seq,
1994 "sk Eth Pid Groups "
1995 "Rmem Wmem Dump Locks Drops Inode\n");
1996 else {
1997 struct sock *s = v;
1998 struct netlink_sock *nlk = nlk_sk(s);
1999
2000 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %-8d %-8d %-8lu\n",
2001 s,
2002 s->sk_protocol,
2003 nlk->pid,
2004 nlk->groups ? (u32)nlk->groups[0] : 0,
2005 sk_rmem_alloc_get(s),
2006 sk_wmem_alloc_get(s),
2007 nlk->cb,
2008 atomic_read(&s->sk_refcnt),
2009 atomic_read(&s->sk_drops),
2010 sock_i_ino(s)
2011 );
2012
2013 }
2014 return 0;
2015}
2016
2017static const struct seq_operations netlink_seq_ops = {
2018 .start = netlink_seq_start,
2019 .next = netlink_seq_next,
2020 .stop = netlink_seq_stop,
2021 .show = netlink_seq_show,
2022};
2023
2024
2025static int netlink_seq_open(struct inode *inode, struct file *file)
2026{
2027 return seq_open_net(inode, file, &netlink_seq_ops,
2028 sizeof(struct nl_seq_iter));
2029}
2030
2031static const struct file_operations netlink_seq_fops = {
2032 .owner = THIS_MODULE,
2033 .open = netlink_seq_open,
2034 .read = seq_read,
2035 .llseek = seq_lseek,
2036 .release = seq_release_net,
2037};
2038
2039#endif
2040
2041int netlink_register_notifier(struct notifier_block *nb)
2042{
2043 return atomic_notifier_chain_register(&netlink_chain, nb);
2044}
2045EXPORT_SYMBOL(netlink_register_notifier);
2046
2047int netlink_unregister_notifier(struct notifier_block *nb)
2048{
2049 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2050}
2051EXPORT_SYMBOL(netlink_unregister_notifier);
2052
2053static const struct proto_ops netlink_ops = {
2054 .family = PF_NETLINK,
2055 .owner = THIS_MODULE,
2056 .release = netlink_release,
2057 .bind = netlink_bind,
2058 .connect = netlink_connect,
2059 .socketpair = sock_no_socketpair,
2060 .accept = sock_no_accept,
2061 .getname = netlink_getname,
2062 .poll = datagram_poll,
2063 .ioctl = sock_no_ioctl,
2064 .listen = sock_no_listen,
2065 .shutdown = sock_no_shutdown,
2066 .setsockopt = netlink_setsockopt,
2067 .getsockopt = netlink_getsockopt,
2068 .sendmsg = netlink_sendmsg,
2069 .recvmsg = netlink_recvmsg,
2070 .mmap = sock_no_mmap,
2071 .sendpage = sock_no_sendpage,
2072};
2073
2074static const struct net_proto_family netlink_family_ops = {
2075 .family = PF_NETLINK,
2076 .create = netlink_create,
2077 .owner = THIS_MODULE, /* for consistency 8) */
2078};
2079
2080static int __net_init netlink_net_init(struct net *net)
2081{
2082#ifdef CONFIG_PROC_FS
2083 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2084 return -ENOMEM;
2085#endif
2086 return 0;
2087}
2088
2089static void __net_exit netlink_net_exit(struct net *net)
2090{
2091#ifdef CONFIG_PROC_FS
2092 proc_net_remove(net, "netlink");
2093#endif
2094}
2095
2096static struct pernet_operations __net_initdata netlink_net_ops = {
2097 .init = netlink_net_init,
2098 .exit = netlink_net_exit,
2099};
2100
2101static int __init netlink_proto_init(void)
2102{
2103 struct sk_buff *dummy_skb;
2104 int i;
2105 unsigned long limit;
2106 unsigned int order;
2107 int err = proto_register(&netlink_proto, 0);
2108
2109 if (err != 0)
2110 goto out;
2111
2112 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2113
2114 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2115 if (!nl_table)
2116 goto panic;
2117
2118 if (totalram_pages >= (128 * 1024))
2119 limit = totalram_pages >> (21 - PAGE_SHIFT);
2120 else
2121 limit = totalram_pages >> (23 - PAGE_SHIFT);
2122
2123 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2124 limit = (1UL << order) / sizeof(struct hlist_head);
2125 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2126
2127 for (i = 0; i < MAX_LINKS; i++) {
2128 struct nl_pid_hash *hash = &nl_table[i].hash;
2129
2130 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
2131 if (!hash->table) {
2132 while (i-- > 0)
2133 nl_pid_hash_free(nl_table[i].hash.table,
2134 1 * sizeof(*hash->table));
2135 kfree(nl_table);
2136 goto panic;
2137 }
2138 hash->max_shift = order;
2139 hash->shift = 0;
2140 hash->mask = 0;
2141 hash->rehash_time = jiffies;
2142 }
2143
2144 sock_register(&netlink_family_ops);
2145 register_pernet_subsys(&netlink_net_ops);
2146 /* The netlink device handler may be needed early. */
2147 rtnetlink_init();
2148out:
2149 return err;
2150panic:
2151 panic("netlink_init: Cannot allocate nl_table\n");
2152}
2153
2154core_initcall(netlink_proto_init);
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