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Merge tag 'batman-adv-for-davem' of git://git.open-mesh.org/linux-merge
[linux-2.6/libata-dev.git] / net / netlink / af_netlink.c
blobfaa48f70b7c9b132bfaf3c8ce561982e82c4c7b6
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
67 struct netlink_sock {
68 /* struct sock has to be the first member of netlink_sock */
69 struct sock sk;
70 u32 pid;
71 u32 dst_pid;
72 u32 dst_group;
73 u32 flags;
74 u32 subscriptions;
75 u32 ngroups;
76 unsigned long *groups;
77 unsigned long state;
78 wait_queue_head_t wait;
79 struct netlink_callback *cb;
80 struct mutex *cb_mutex;
81 struct mutex cb_def_mutex;
82 void (*netlink_rcv)(struct sk_buff *skb);
83 struct module *module;
84 };
85
86 struct listeners {
87 struct rcu_head rcu;
88 unsigned long masks[0];
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
96 static inline struct netlink_sock *nlk_sk(struct sock *sk)
97 {
98 return container_of(sk, struct netlink_sock, sk);
99 }
100
101 static inline int netlink_is_kernel(struct sock *sk)
102 {
103 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
104 }
105
106 struct 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
119 struct netlink_table {
120 struct nl_pid_hash hash;
121 struct hlist_head mc_list;
122 struct listeners __rcu *listeners;
123 unsigned int nl_nonroot;
124 unsigned int groups;
125 struct mutex *cb_mutex;
126 struct module *module;
127 int registered;
128 };
129
130 static struct netlink_table *nl_table;
131
132 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
133
134 static int netlink_dump(struct sock *sk);
135 static void netlink_destroy_callback(struct netlink_callback *cb);
136
137 static DEFINE_RWLOCK(nl_table_lock);
138 static atomic_t nl_table_users = ATOMIC_INIT(0);
139
140 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
141
142 static inline u32 netlink_group_mask(u32 group)
143 {
144 return group ? 1 << (group - 1) : 0;
145 }
146
147 static inline 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
152 static 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
180 void 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
205 void 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
212 static inline void
213 netlink_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
222 static inline void
223 netlink_unlock_table(void)
224 {
225 if (atomic_dec_and_test(&nl_table_users))
226 wake_up(&nl_table_wait);
227 }
228
229 static struct sock *netlink_lookup(struct net *net, int protocol, u32 pid)
230 {
231 struct nl_pid_hash *hash = &nl_table[protocol].hash;
232 struct hlist_head *head;
233 struct sock *sk;
234 struct hlist_node *node;
235
236 read_lock(&nl_table_lock);
237 head = nl_pid_hashfn(hash, pid);
238 sk_for_each(sk, node, head) {
239 if (net_eq(sock_net(sk), net) && (nlk_sk(sk)->pid == pid)) {
240 sock_hold(sk);
241 goto found;
242 }
243 }
244 sk = NULL;
245 found:
246 read_unlock(&nl_table_lock);
247 return sk;
248 }
249
250 static struct hlist_head *nl_pid_hash_zalloc(size_t size)
251 {
252 if (size <= PAGE_SIZE)
253 return kzalloc(size, GFP_ATOMIC);
254 else
255 return (struct hlist_head *)
256 __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
257 get_order(size));
258 }
259
260 static void nl_pid_hash_free(struct hlist_head *table, size_t size)
261 {
262 if (size <= PAGE_SIZE)
263 kfree(table);
264 else
265 free_pages((unsigned long)table, get_order(size));
266 }
267
268 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
269 {
270 unsigned int omask, mask, shift;
271 size_t osize, size;
272 struct hlist_head *otable, *table;
273 int i;
274
275 omask = mask = hash->mask;
276 osize = size = (mask + 1) * sizeof(*table);
277 shift = hash->shift;
278
279 if (grow) {
280 if (++shift > hash->max_shift)
281 return 0;
282 mask = mask * 2 + 1;
283 size *= 2;
284 }
285
286 table = nl_pid_hash_zalloc(size);
287 if (!table)
288 return 0;
289
290 otable = hash->table;
291 hash->table = table;
292 hash->mask = mask;
293 hash->shift = shift;
294 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
295
296 for (i = 0; i <= omask; i++) {
297 struct sock *sk;
298 struct hlist_node *node, *tmp;
299
300 sk_for_each_safe(sk, node, tmp, &otable[i])
301 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
302 }
303
304 nl_pid_hash_free(otable, osize);
305 hash->rehash_time = jiffies + 10 * 60 * HZ;
306 return 1;
307 }
308
309 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
310 {
311 int avg = hash->entries >> hash->shift;
312
313 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
314 return 1;
315
316 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
317 nl_pid_hash_rehash(hash, 0);
318 return 1;
319 }
320
321 return 0;
322 }
323
324 static const struct proto_ops netlink_ops;
325
326 static void
327 netlink_update_listeners(struct sock *sk)
328 {
329 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
330 struct hlist_node *node;
331 unsigned long mask;
332 unsigned int i;
333
334 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
335 mask = 0;
336 sk_for_each_bound(sk, node, &tbl->mc_list) {
337 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
338 mask |= nlk_sk(sk)->groups[i];
339 }
340 tbl->listeners->masks[i] = mask;
341 }
342 /* this function is only called with the netlink table "grabbed", which
343 * makes sure updates are visible before bind or setsockopt return. */
344 }
345
346 static int netlink_insert(struct sock *sk, struct net *net, u32 pid)
347 {
348 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
349 struct hlist_head *head;
350 int err = -EADDRINUSE;
351 struct sock *osk;
352 struct hlist_node *node;
353 int len;
354
355 netlink_table_grab();
356 head = nl_pid_hashfn(hash, pid);
357 len = 0;
358 sk_for_each(osk, node, head) {
359 if (net_eq(sock_net(osk), net) && (nlk_sk(osk)->pid == pid))
360 break;
361 len++;
362 }
363 if (node)
364 goto err;
365
366 err = -EBUSY;
367 if (nlk_sk(sk)->pid)
368 goto err;
369
370 err = -ENOMEM;
371 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
372 goto err;
373
374 if (len && nl_pid_hash_dilute(hash, len))
375 head = nl_pid_hashfn(hash, pid);
376 hash->entries++;
377 nlk_sk(sk)->pid = pid;
378 sk_add_node(sk, head);
379 err = 0;
380
381 err:
382 netlink_table_ungrab();
383 return err;
384 }
385
386 static void netlink_remove(struct sock *sk)
387 {
388 netlink_table_grab();
389 if (sk_del_node_init(sk))
390 nl_table[sk->sk_protocol].hash.entries--;
391 if (nlk_sk(sk)->subscriptions)
392 __sk_del_bind_node(sk);
393 netlink_table_ungrab();
394 }
395
396 static struct proto netlink_proto = {
397 .name = "NETLINK",
398 .owner = THIS_MODULE,
399 .obj_size = sizeof(struct netlink_sock),
400 };
401
402 static int __netlink_create(struct net *net, struct socket *sock,
403 struct mutex *cb_mutex, int protocol)
404 {
405 struct sock *sk;
406 struct netlink_sock *nlk;
407
408 sock->ops = &netlink_ops;
409
410 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
411 if (!sk)
412 return -ENOMEM;
413
414 sock_init_data(sock, sk);
415
416 nlk = nlk_sk(sk);
417 if (cb_mutex)
418 nlk->cb_mutex = cb_mutex;
419 else {
420 nlk->cb_mutex = &nlk->cb_def_mutex;
421 mutex_init(nlk->cb_mutex);
422 }
423 init_waitqueue_head(&nlk->wait);
424
425 sk->sk_destruct = netlink_sock_destruct;
426 sk->sk_protocol = protocol;
427 return 0;
428 }
429
430 static int netlink_create(struct net *net, struct socket *sock, int protocol,
431 int kern)
432 {
433 struct module *module = NULL;
434 struct mutex *cb_mutex;
435 struct netlink_sock *nlk;
436 int err = 0;
437
438 sock->state = SS_UNCONNECTED;
439
440 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
441 return -ESOCKTNOSUPPORT;
442
443 if (protocol < 0 || protocol >= MAX_LINKS)
444 return -EPROTONOSUPPORT;
445
446 netlink_lock_table();
447 #ifdef CONFIG_MODULES
448 if (!nl_table[protocol].registered) {
449 netlink_unlock_table();
450 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
451 netlink_lock_table();
452 }
453 #endif
454 if (nl_table[protocol].registered &&
455 try_module_get(nl_table[protocol].module))
456 module = nl_table[protocol].module;
457 else
458 err = -EPROTONOSUPPORT;
459 cb_mutex = nl_table[protocol].cb_mutex;
460 netlink_unlock_table();
461
462 if (err < 0)
463 goto out;
464
465 err = __netlink_create(net, sock, cb_mutex, protocol);
466 if (err < 0)
467 goto out_module;
468
469 local_bh_disable();
470 sock_prot_inuse_add(net, &netlink_proto, 1);
471 local_bh_enable();
472
473 nlk = nlk_sk(sock->sk);
474 nlk->module = module;
475 out:
476 return err;
477
478 out_module:
479 module_put(module);
480 goto out;
481 }
482
483 static int netlink_release(struct socket *sock)
484 {
485 struct sock *sk = sock->sk;
486 struct netlink_sock *nlk;
487
488 if (!sk)
489 return 0;
490
491 netlink_remove(sk);
492 sock_orphan(sk);
493 nlk = nlk_sk(sk);
494
495 /*
496 * OK. Socket is unlinked, any packets that arrive now
497 * will be purged.
498 */
499
500 sock->sk = NULL;
501 wake_up_interruptible_all(&nlk->wait);
502
503 skb_queue_purge(&sk->sk_write_queue);
504
505 if (nlk->pid) {
506 struct netlink_notify n = {
507 .net = sock_net(sk),
508 .protocol = sk->sk_protocol,
509 .pid = nlk->pid,
510 };
511 atomic_notifier_call_chain(&netlink_chain,
512 NETLINK_URELEASE, &n);
513 }
514
515 module_put(nlk->module);
516
517 netlink_table_grab();
518 if (netlink_is_kernel(sk)) {
519 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
520 if (--nl_table[sk->sk_protocol].registered == 0) {
521 kfree(nl_table[sk->sk_protocol].listeners);
522 nl_table[sk->sk_protocol].module = NULL;
523 nl_table[sk->sk_protocol].registered = 0;
524 }
525 } else if (nlk->subscriptions)
526 netlink_update_listeners(sk);
527 netlink_table_ungrab();
528
529 kfree(nlk->groups);
530 nlk->groups = NULL;
531
532 local_bh_disable();
533 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
534 local_bh_enable();
535 sock_put(sk);
536 return 0;
537 }
538
539 static int netlink_autobind(struct socket *sock)
540 {
541 struct sock *sk = sock->sk;
542 struct net *net = sock_net(sk);
543 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
544 struct hlist_head *head;
545 struct sock *osk;
546 struct hlist_node *node;
547 s32 pid = task_tgid_vnr(current);
548 int err;
549 static s32 rover = -4097;
550
551 retry:
552 cond_resched();
553 netlink_table_grab();
554 head = nl_pid_hashfn(hash, pid);
555 sk_for_each(osk, node, head) {
556 if (!net_eq(sock_net(osk), net))
557 continue;
558 if (nlk_sk(osk)->pid == pid) {
559 /* Bind collision, search negative pid values. */
560 pid = rover--;
561 if (rover > -4097)
562 rover = -4097;
563 netlink_table_ungrab();
564 goto retry;
565 }
566 }
567 netlink_table_ungrab();
568
569 err = netlink_insert(sk, net, pid);
570 if (err == -EADDRINUSE)
571 goto retry;
572
573 /* If 2 threads race to autobind, that is fine. */
574 if (err == -EBUSY)
575 err = 0;
576
577 return err;
578 }
579
580 static inline int netlink_capable(const struct socket *sock, unsigned int flag)
581 {
582 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
583 capable(CAP_NET_ADMIN);
584 }
585
586 static void
587 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
588 {
589 struct netlink_sock *nlk = nlk_sk(sk);
590
591 if (nlk->subscriptions && !subscriptions)
592 __sk_del_bind_node(sk);
593 else if (!nlk->subscriptions && subscriptions)
594 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
595 nlk->subscriptions = subscriptions;
596 }
597
598 static int netlink_realloc_groups(struct sock *sk)
599 {
600 struct netlink_sock *nlk = nlk_sk(sk);
601 unsigned int groups;
602 unsigned long *new_groups;
603 int err = 0;
604
605 netlink_table_grab();
606
607 groups = nl_table[sk->sk_protocol].groups;
608 if (!nl_table[sk->sk_protocol].registered) {
609 err = -ENOENT;
610 goto out_unlock;
611 }
612
613 if (nlk->ngroups >= groups)
614 goto out_unlock;
615
616 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
617 if (new_groups == NULL) {
618 err = -ENOMEM;
619 goto out_unlock;
620 }
621 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
622 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
623
624 nlk->groups = new_groups;
625 nlk->ngroups = groups;
626 out_unlock:
627 netlink_table_ungrab();
628 return err;
629 }
630
631 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
632 int addr_len)
633 {
634 struct sock *sk = sock->sk;
635 struct net *net = sock_net(sk);
636 struct netlink_sock *nlk = nlk_sk(sk);
637 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
638 int err;
639
640 if (nladdr->nl_family != AF_NETLINK)
641 return -EINVAL;
642
643 /* Only superuser is allowed to listen multicasts */
644 if (nladdr->nl_groups) {
645 if (!netlink_capable(sock, NL_NONROOT_RECV))
646 return -EPERM;
647 err = netlink_realloc_groups(sk);
648 if (err)
649 return err;
650 }
651
652 if (nlk->pid) {
653 if (nladdr->nl_pid != nlk->pid)
654 return -EINVAL;
655 } else {
656 err = nladdr->nl_pid ?
657 netlink_insert(sk, net, nladdr->nl_pid) :
658 netlink_autobind(sock);
659 if (err)
660 return err;
661 }
662
663 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
664 return 0;
665
666 netlink_table_grab();
667 netlink_update_subscriptions(sk, nlk->subscriptions +
668 hweight32(nladdr->nl_groups) -
669 hweight32(nlk->groups[0]));
670 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
671 netlink_update_listeners(sk);
672 netlink_table_ungrab();
673
674 return 0;
675 }
676
677 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
678 int alen, int flags)
679 {
680 int err = 0;
681 struct sock *sk = sock->sk;
682 struct netlink_sock *nlk = nlk_sk(sk);
683 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
684
685 if (alen < sizeof(addr->sa_family))
686 return -EINVAL;
687
688 if (addr->sa_family == AF_UNSPEC) {
689 sk->sk_state = NETLINK_UNCONNECTED;
690 nlk->dst_pid = 0;
691 nlk->dst_group = 0;
692 return 0;
693 }
694 if (addr->sa_family != AF_NETLINK)
695 return -EINVAL;
696
697 /* Only superuser is allowed to send multicasts */
698 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
699 return -EPERM;
700
701 if (!nlk->pid)
702 err = netlink_autobind(sock);
703
704 if (err == 0) {
705 sk->sk_state = NETLINK_CONNECTED;
706 nlk->dst_pid = nladdr->nl_pid;
707 nlk->dst_group = ffs(nladdr->nl_groups);
708 }
709
710 return err;
711 }
712
713 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
714 int *addr_len, int peer)
715 {
716 struct sock *sk = sock->sk;
717 struct netlink_sock *nlk = nlk_sk(sk);
718 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
719
720 nladdr->nl_family = AF_NETLINK;
721 nladdr->nl_pad = 0;
722 *addr_len = sizeof(*nladdr);
723
724 if (peer) {
725 nladdr->nl_pid = nlk->dst_pid;
726 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
727 } else {
728 nladdr->nl_pid = nlk->pid;
729 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
730 }
731 return 0;
732 }
733
734 static void netlink_overrun(struct sock *sk)
735 {
736 struct netlink_sock *nlk = nlk_sk(sk);
737
738 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
739 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
740 sk->sk_err = ENOBUFS;
741 sk->sk_error_report(sk);
742 }
743 }
744 atomic_inc(&sk->sk_drops);
745 }
746
747 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
748 {
749 struct sock *sock;
750 struct netlink_sock *nlk;
751
752 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, pid);
753 if (!sock)
754 return ERR_PTR(-ECONNREFUSED);
755
756 /* Don't bother queuing skb if kernel socket has no input function */
757 nlk = nlk_sk(sock);
758 if (sock->sk_state == NETLINK_CONNECTED &&
759 nlk->dst_pid != nlk_sk(ssk)->pid) {
760 sock_put(sock);
761 return ERR_PTR(-ECONNREFUSED);
762 }
763 return sock;
764 }
765
766 struct sock *netlink_getsockbyfilp(struct file *filp)
767 {
768 struct inode *inode = filp->f_path.dentry->d_inode;
769 struct sock *sock;
770
771 if (!S_ISSOCK(inode->i_mode))
772 return ERR_PTR(-ENOTSOCK);
773
774 sock = SOCKET_I(inode)->sk;
775 if (sock->sk_family != AF_NETLINK)
776 return ERR_PTR(-EINVAL);
777
778 sock_hold(sock);
779 return sock;
780 }
781
782 /*
783 * Attach a skb to a netlink socket.
784 * The caller must hold a reference to the destination socket. On error, the
785 * reference is dropped. The skb is not send to the destination, just all
786 * all error checks are performed and memory in the queue is reserved.
787 * Return values:
788 * < 0: error. skb freed, reference to sock dropped.
789 * 0: continue
790 * 1: repeat lookup - reference dropped while waiting for socket memory.
791 */
792 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
793 long *timeo, struct sock *ssk)
794 {
795 struct netlink_sock *nlk;
796
797 nlk = nlk_sk(sk);
798
799 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
800 test_bit(0, &nlk->state)) {
801 DECLARE_WAITQUEUE(wait, current);
802 if (!*timeo) {
803 if (!ssk || netlink_is_kernel(ssk))
804 netlink_overrun(sk);
805 sock_put(sk);
806 kfree_skb(skb);
807 return -EAGAIN;
808 }
809
810 __set_current_state(TASK_INTERRUPTIBLE);
811 add_wait_queue(&nlk->wait, &wait);
812
813 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
814 test_bit(0, &nlk->state)) &&
815 !sock_flag(sk, SOCK_DEAD))
816 *timeo = schedule_timeout(*timeo);
817
818 __set_current_state(TASK_RUNNING);
819 remove_wait_queue(&nlk->wait, &wait);
820 sock_put(sk);
821
822 if (signal_pending(current)) {
823 kfree_skb(skb);
824 return sock_intr_errno(*timeo);
825 }
826 return 1;
827 }
828 skb_set_owner_r(skb, sk);
829 return 0;
830 }
831
832 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
833 {
834 int len = skb->len;
835
836 skb_queue_tail(&sk->sk_receive_queue, skb);
837 sk->sk_data_ready(sk, len);
838 return len;
839 }
840
841 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
842 {
843 int len = __netlink_sendskb(sk, skb);
844
845 sock_put(sk);
846 return len;
847 }
848
849 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
850 {
851 kfree_skb(skb);
852 sock_put(sk);
853 }
854
855 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
856 {
857 int delta;
858
859 skb_orphan(skb);
860
861 delta = skb->end - skb->tail;
862 if (delta * 2 < skb->truesize)
863 return skb;
864
865 if (skb_shared(skb)) {
866 struct sk_buff *nskb = skb_clone(skb, allocation);
867 if (!nskb)
868 return skb;
869 kfree_skb(skb);
870 skb = nskb;
871 }
872
873 if (!pskb_expand_head(skb, 0, -delta, allocation))
874 skb->truesize -= delta;
875
876 return skb;
877 }
878
879 static void netlink_rcv_wake(struct sock *sk)
880 {
881 struct netlink_sock *nlk = nlk_sk(sk);
882
883 if (skb_queue_empty(&sk->sk_receive_queue))
884 clear_bit(0, &nlk->state);
885 if (!test_bit(0, &nlk->state))
886 wake_up_interruptible(&nlk->wait);
887 }
888
889 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb)
890 {
891 int ret;
892 struct netlink_sock *nlk = nlk_sk(sk);
893
894 ret = -ECONNREFUSED;
895 if (nlk->netlink_rcv != NULL) {
896 ret = skb->len;
897 skb_set_owner_r(skb, sk);
898 nlk->netlink_rcv(skb);
899 }
900 kfree_skb(skb);
901 sock_put(sk);
902 return ret;
903 }
904
905 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
906 u32 pid, int nonblock)
907 {
908 struct sock *sk;
909 int err;
910 long timeo;
911
912 skb = netlink_trim(skb, gfp_any());
913
914 timeo = sock_sndtimeo(ssk, nonblock);
915 retry:
916 sk = netlink_getsockbypid(ssk, pid);
917 if (IS_ERR(sk)) {
918 kfree_skb(skb);
919 return PTR_ERR(sk);
920 }
921 if (netlink_is_kernel(sk))
922 return netlink_unicast_kernel(sk, skb);
923
924 if (sk_filter(sk, skb)) {
925 err = skb->len;
926 kfree_skb(skb);
927 sock_put(sk);
928 return err;
929 }
930
931 err = netlink_attachskb(sk, skb, &timeo, ssk);
932 if (err == 1)
933 goto retry;
934 if (err)
935 return err;
936
937 return netlink_sendskb(sk, skb);
938 }
939 EXPORT_SYMBOL(netlink_unicast);
940
941 int netlink_has_listeners(struct sock *sk, unsigned int group)
942 {
943 int res = 0;
944 struct listeners *listeners;
945
946 BUG_ON(!netlink_is_kernel(sk));
947
948 rcu_read_lock();
949 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
950
951 if (group - 1 < nl_table[sk->sk_protocol].groups)
952 res = test_bit(group - 1, listeners->masks);
953
954 rcu_read_unlock();
955
956 return res;
957 }
958 EXPORT_SYMBOL_GPL(netlink_has_listeners);
959
960 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
961 {
962 struct netlink_sock *nlk = nlk_sk(sk);
963
964 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
965 !test_bit(0, &nlk->state)) {
966 skb_set_owner_r(skb, sk);
967 __netlink_sendskb(sk, skb);
968 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
969 }
970 return -1;
971 }
972
973 struct netlink_broadcast_data {
974 struct sock *exclude_sk;
975 struct net *net;
976 u32 pid;
977 u32 group;
978 int failure;
979 int delivery_failure;
980 int congested;
981 int delivered;
982 gfp_t allocation;
983 struct sk_buff *skb, *skb2;
984 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
985 void *tx_data;
986 };
987
988 static int do_one_broadcast(struct sock *sk,
989 struct netlink_broadcast_data *p)
990 {
991 struct netlink_sock *nlk = nlk_sk(sk);
992 int val;
993
994 if (p->exclude_sk == sk)
995 goto out;
996
997 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
998 !test_bit(p->group - 1, nlk->groups))
999 goto out;
1000
1001 if (!net_eq(sock_net(sk), p->net))
1002 goto out;
1003
1004 if (p->failure) {
1005 netlink_overrun(sk);
1006 goto out;
1007 }
1008
1009 sock_hold(sk);
1010 if (p->skb2 == NULL) {
1011 if (skb_shared(p->skb)) {
1012 p->skb2 = skb_clone(p->skb, p->allocation);
1013 } else {
1014 p->skb2 = skb_get(p->skb);
1015 /*
1016 * skb ownership may have been set when
1017 * delivered to a previous socket.
1018 */
1019 skb_orphan(p->skb2);
1020 }
1021 }
1022 if (p->skb2 == NULL) {
1023 netlink_overrun(sk);
1024 /* Clone failed. Notify ALL listeners. */
1025 p->failure = 1;
1026 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1027 p->delivery_failure = 1;
1028 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1029 kfree_skb(p->skb2);
1030 p->skb2 = NULL;
1031 } else if (sk_filter(sk, p->skb2)) {
1032 kfree_skb(p->skb2);
1033 p->skb2 = NULL;
1034 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1035 netlink_overrun(sk);
1036 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1037 p->delivery_failure = 1;
1038 } else {
1039 p->congested |= val;
1040 p->delivered = 1;
1041 p->skb2 = NULL;
1042 }
1043 sock_put(sk);
1044
1045 out:
1046 return 0;
1047 }
1048
1049 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 pid,
1050 u32 group, gfp_t allocation,
1051 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1052 void *filter_data)
1053 {
1054 struct net *net = sock_net(ssk);
1055 struct netlink_broadcast_data info;
1056 struct hlist_node *node;
1057 struct sock *sk;
1058
1059 skb = netlink_trim(skb, allocation);
1060
1061 info.exclude_sk = ssk;
1062 info.net = net;
1063 info.pid = pid;
1064 info.group = group;
1065 info.failure = 0;
1066 info.delivery_failure = 0;
1067 info.congested = 0;
1068 info.delivered = 0;
1069 info.allocation = allocation;
1070 info.skb = skb;
1071 info.skb2 = NULL;
1072 info.tx_filter = filter;
1073 info.tx_data = filter_data;
1074
1075 /* While we sleep in clone, do not allow to change socket list */
1076
1077 netlink_lock_table();
1078
1079 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1080 do_one_broadcast(sk, &info);
1081
1082 consume_skb(skb);
1083
1084 netlink_unlock_table();
1085
1086 if (info.delivery_failure) {
1087 kfree_skb(info.skb2);
1088 return -ENOBUFS;
1089 } else
1090 consume_skb(info.skb2);
1091
1092 if (info.delivered) {
1093 if (info.congested && (allocation & __GFP_WAIT))
1094 yield();
1095 return 0;
1096 }
1097 return -ESRCH;
1098 }
1099 EXPORT_SYMBOL(netlink_broadcast_filtered);
1100
1101 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
1102 u32 group, gfp_t allocation)
1103 {
1104 return netlink_broadcast_filtered(ssk, skb, pid, group, allocation,
1105 NULL, NULL);
1106 }
1107 EXPORT_SYMBOL(netlink_broadcast);
1108
1109 struct netlink_set_err_data {
1110 struct sock *exclude_sk;
1111 u32 pid;
1112 u32 group;
1113 int code;
1114 };
1115
1116 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1117 {
1118 struct netlink_sock *nlk = nlk_sk(sk);
1119 int ret = 0;
1120
1121 if (sk == p->exclude_sk)
1122 goto out;
1123
1124 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
1125 goto out;
1126
1127 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
1128 !test_bit(p->group - 1, nlk->groups))
1129 goto out;
1130
1131 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
1132 ret = 1;
1133 goto out;
1134 }
1135
1136 sk->sk_err = p->code;
1137 sk->sk_error_report(sk);
1138 out:
1139 return ret;
1140 }
1141
1142 /**
1143 * netlink_set_err - report error to broadcast listeners
1144 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1145 * @pid: the PID of a process that we want to skip (if any)
1146 * @groups: the broadcast group that will notice the error
1147 * @code: error code, must be negative (as usual in kernelspace)
1148 *
1149 * This function returns the number of broadcast listeners that have set the
1150 * NETLINK_RECV_NO_ENOBUFS socket option.
1151 */
1152 int netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
1153 {
1154 struct netlink_set_err_data info;
1155 struct hlist_node *node;
1156 struct sock *sk;
1157 int ret = 0;
1158
1159 info.exclude_sk = ssk;
1160 info.pid = pid;
1161 info.group = group;
1162 /* sk->sk_err wants a positive error value */
1163 info.code = -code;
1164
1165 read_lock(&nl_table_lock);
1166
1167 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
1168 ret += do_one_set_err(sk, &info);
1169
1170 read_unlock(&nl_table_lock);
1171 return ret;
1172 }
1173 EXPORT_SYMBOL(netlink_set_err);
1174
1175 /* must be called with netlink table grabbed */
1176 static void netlink_update_socket_mc(struct netlink_sock *nlk,
1177 unsigned int group,
1178 int is_new)
1179 {
1180 int old, new = !!is_new, subscriptions;
1181
1182 old = test_bit(group - 1, nlk->groups);
1183 subscriptions = nlk->subscriptions - old + new;
1184 if (new)
1185 __set_bit(group - 1, nlk->groups);
1186 else
1187 __clear_bit(group - 1, nlk->groups);
1188 netlink_update_subscriptions(&nlk->sk, subscriptions);
1189 netlink_update_listeners(&nlk->sk);
1190 }
1191
1192 static int netlink_setsockopt(struct socket *sock, int level, int optname,
1193 char __user *optval, unsigned int optlen)
1194 {
1195 struct sock *sk = sock->sk;
1196 struct netlink_sock *nlk = nlk_sk(sk);
1197 unsigned int val = 0;
1198 int err;
1199
1200 if (level != SOL_NETLINK)
1201 return -ENOPROTOOPT;
1202
1203 if (optlen >= sizeof(int) &&
1204 get_user(val, (unsigned int __user *)optval))
1205 return -EFAULT;
1206
1207 switch (optname) {
1208 case NETLINK_PKTINFO:
1209 if (val)
1210 nlk->flags |= NETLINK_RECV_PKTINFO;
1211 else
1212 nlk->flags &= ~NETLINK_RECV_PKTINFO;
1213 err = 0;
1214 break;
1215 case NETLINK_ADD_MEMBERSHIP:
1216 case NETLINK_DROP_MEMBERSHIP: {
1217 if (!netlink_capable(sock, NL_NONROOT_RECV))
1218 return -EPERM;
1219 err = netlink_realloc_groups(sk);
1220 if (err)
1221 return err;
1222 if (!val || val - 1 >= nlk->ngroups)
1223 return -EINVAL;
1224 netlink_table_grab();
1225 netlink_update_socket_mc(nlk, val,
1226 optname == NETLINK_ADD_MEMBERSHIP);
1227 netlink_table_ungrab();
1228 err = 0;
1229 break;
1230 }
1231 case NETLINK_BROADCAST_ERROR:
1232 if (val)
1233 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
1234 else
1235 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
1236 err = 0;
1237 break;
1238 case NETLINK_NO_ENOBUFS:
1239 if (val) {
1240 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
1241 clear_bit(0, &nlk->state);
1242 wake_up_interruptible(&nlk->wait);
1243 } else
1244 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
1245 err = 0;
1246 break;
1247 default:
1248 err = -ENOPROTOOPT;
1249 }
1250 return err;
1251 }
1252
1253 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1254 char __user *optval, int __user *optlen)
1255 {
1256 struct sock *sk = sock->sk;
1257 struct netlink_sock *nlk = nlk_sk(sk);
1258 int len, val, err;
1259
1260 if (level != SOL_NETLINK)
1261 return -ENOPROTOOPT;
1262
1263 if (get_user(len, optlen))
1264 return -EFAULT;
1265 if (len < 0)
1266 return -EINVAL;
1267
1268 switch (optname) {
1269 case NETLINK_PKTINFO:
1270 if (len < sizeof(int))
1271 return -EINVAL;
1272 len = sizeof(int);
1273 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1274 if (put_user(len, optlen) ||
1275 put_user(val, optval))
1276 return -EFAULT;
1277 err = 0;
1278 break;
1279 case NETLINK_BROADCAST_ERROR:
1280 if (len < sizeof(int))
1281 return -EINVAL;
1282 len = sizeof(int);
1283 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
1284 if (put_user(len, optlen) ||
1285 put_user(val, optval))
1286 return -EFAULT;
1287 err = 0;
1288 break;
1289 case NETLINK_NO_ENOBUFS:
1290 if (len < sizeof(int))
1291 return -EINVAL;
1292 len = sizeof(int);
1293 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
1294 if (put_user(len, optlen) ||
1295 put_user(val, optval))
1296 return -EFAULT;
1297 err = 0;
1298 break;
1299 default:
1300 err = -ENOPROTOOPT;
1301 }
1302 return err;
1303 }
1304
1305 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1306 {
1307 struct nl_pktinfo info;
1308
1309 info.group = NETLINK_CB(skb).dst_group;
1310 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1311 }
1312
1313 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1314 struct msghdr *msg, size_t len)
1315 {
1316 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1317 struct sock *sk = sock->sk;
1318 struct netlink_sock *nlk = nlk_sk(sk);
1319 struct sockaddr_nl *addr = msg->msg_name;
1320 u32 dst_pid;
1321 u32 dst_group;
1322 struct sk_buff *skb;
1323 int err;
1324 struct scm_cookie scm;
1325
1326 if (msg->msg_flags&MSG_OOB)
1327 return -EOPNOTSUPP;
1328
1329 if (NULL == siocb->scm)
1330 siocb->scm = &scm;
1331
1332 err = scm_send(sock, msg, siocb->scm);
1333 if (err < 0)
1334 return err;
1335
1336 if (msg->msg_namelen) {
1337 err = -EINVAL;
1338 if (addr->nl_family != AF_NETLINK)
1339 goto out;
1340 dst_pid = addr->nl_pid;
1341 dst_group = ffs(addr->nl_groups);
1342 err = -EPERM;
1343 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1344 goto out;
1345 } else {
1346 dst_pid = nlk->dst_pid;
1347 dst_group = nlk->dst_group;
1348 }
1349
1350 if (!nlk->pid) {
1351 err = netlink_autobind(sock);
1352 if (err)
1353 goto out;
1354 }
1355
1356 err = -EMSGSIZE;
1357 if (len > sk->sk_sndbuf - 32)
1358 goto out;
1359 err = -ENOBUFS;
1360 skb = alloc_skb(len, GFP_KERNEL);
1361 if (skb == NULL)
1362 goto out;
1363
1364 NETLINK_CB(skb).pid = nlk->pid;
1365 NETLINK_CB(skb).dst_group = dst_group;
1366 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1367
1368 err = -EFAULT;
1369 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
1370 kfree_skb(skb);
1371 goto out;
1372 }
1373
1374 err = security_netlink_send(sk, skb);
1375 if (err) {
1376 kfree_skb(skb);
1377 goto out;
1378 }
1379
1380 if (dst_group) {
1381 atomic_inc(&skb->users);
1382 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1383 }
1384 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1385
1386 out:
1387 scm_destroy(siocb->scm);
1388 return err;
1389 }
1390
1391 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1392 struct msghdr *msg, size_t len,
1393 int flags)
1394 {
1395 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1396 struct scm_cookie scm;
1397 struct sock *sk = sock->sk;
1398 struct netlink_sock *nlk = nlk_sk(sk);
1399 int noblock = flags&MSG_DONTWAIT;
1400 size_t copied;
1401 struct sk_buff *skb, *data_skb;
1402 int err, ret;
1403
1404 if (flags&MSG_OOB)
1405 return -EOPNOTSUPP;
1406
1407 copied = 0;
1408
1409 skb = skb_recv_datagram(sk, flags, noblock, &err);
1410 if (skb == NULL)
1411 goto out;
1412
1413 data_skb = skb;
1414
1415 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1416 if (unlikely(skb_shinfo(skb)->frag_list)) {
1417 /*
1418 * If this skb has a frag_list, then here that means that we
1419 * will have to use the frag_list skb's data for compat tasks
1420 * and the regular skb's data for normal (non-compat) tasks.
1421 *
1422 * If we need to send the compat skb, assign it to the
1423 * 'data_skb' variable so that it will be used below for data
1424 * copying. We keep 'skb' for everything else, including
1425 * freeing both later.
1426 */
1427 if (flags & MSG_CMSG_COMPAT)
1428 data_skb = skb_shinfo(skb)->frag_list;
1429 }
1430 #endif
1431
1432 msg->msg_namelen = 0;
1433
1434 copied = data_skb->len;
1435 if (len < copied) {
1436 msg->msg_flags |= MSG_TRUNC;
1437 copied = len;
1438 }
1439
1440 skb_reset_transport_header(data_skb);
1441 err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
1442
1443 if (msg->msg_name) {
1444 struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
1445 addr->nl_family = AF_NETLINK;
1446 addr->nl_pad = 0;
1447 addr->nl_pid = NETLINK_CB(skb).pid;
1448 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1449 msg->msg_namelen = sizeof(*addr);
1450 }
1451
1452 if (nlk->flags & NETLINK_RECV_PKTINFO)
1453 netlink_cmsg_recv_pktinfo(msg, skb);
1454
1455 if (NULL == siocb->scm) {
1456 memset(&scm, 0, sizeof(scm));
1457 siocb->scm = &scm;
1458 }
1459 siocb->scm->creds = *NETLINK_CREDS(skb);
1460 if (flags & MSG_TRUNC)
1461 copied = data_skb->len;
1462
1463 skb_free_datagram(sk, skb);
1464
1465 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
1466 ret = netlink_dump(sk);
1467 if (ret) {
1468 sk->sk_err = ret;
1469 sk->sk_error_report(sk);
1470 }
1471 }
1472
1473 scm_recv(sock, msg, siocb->scm, flags);
1474 out:
1475 netlink_rcv_wake(sk);
1476 return err ? : copied;
1477 }
1478
1479 static void netlink_data_ready(struct sock *sk, int len)
1480 {
1481 BUG();
1482 }
1483
1484 /*
1485 * We export these functions to other modules. They provide a
1486 * complete set of kernel non-blocking support for message
1487 * queueing.
1488 */
1489
1490 struct sock *
1491 netlink_kernel_create(struct net *net, int unit, unsigned int groups,
1492 void (*input)(struct sk_buff *skb),
1493 struct mutex *cb_mutex, struct module *module)
1494 {
1495 struct socket *sock;
1496 struct sock *sk;
1497 struct netlink_sock *nlk;
1498 struct listeners *listeners = NULL;
1499
1500 BUG_ON(!nl_table);
1501
1502 if (unit < 0 || unit >= MAX_LINKS)
1503 return NULL;
1504
1505 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1506 return NULL;
1507
1508 /*
1509 * We have to just have a reference on the net from sk, but don't
1510 * get_net it. Besides, we cannot get and then put the net here.
1511 * So we create one inside init_net and the move it to net.
1512 */
1513
1514 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
1515 goto out_sock_release_nosk;
1516
1517 sk = sock->sk;
1518 sk_change_net(sk, net);
1519
1520 if (groups < 32)
1521 groups = 32;
1522
1523 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
1524 if (!listeners)
1525 goto out_sock_release;
1526
1527 sk->sk_data_ready = netlink_data_ready;
1528 if (input)
1529 nlk_sk(sk)->netlink_rcv = input;
1530
1531 if (netlink_insert(sk, net, 0))
1532 goto out_sock_release;
1533
1534 nlk = nlk_sk(sk);
1535 nlk->flags |= NETLINK_KERNEL_SOCKET;
1536
1537 netlink_table_grab();
1538 if (!nl_table[unit].registered) {
1539 nl_table[unit].groups = groups;
1540 rcu_assign_pointer(nl_table[unit].listeners, listeners);
1541 nl_table[unit].cb_mutex = cb_mutex;
1542 nl_table[unit].module = module;
1543 nl_table[unit].registered = 1;
1544 } else {
1545 kfree(listeners);
1546 nl_table[unit].registered++;
1547 }
1548 netlink_table_ungrab();
1549 return sk;
1550
1551 out_sock_release:
1552 kfree(listeners);
1553 netlink_kernel_release(sk);
1554 return NULL;
1555
1556 out_sock_release_nosk:
1557 sock_release(sock);
1558 return NULL;
1559 }
1560 EXPORT_SYMBOL(netlink_kernel_create);
1561
1562
1563 void
1564 netlink_kernel_release(struct sock *sk)
1565 {
1566 sk_release_kernel(sk);
1567 }
1568 EXPORT_SYMBOL(netlink_kernel_release);
1569
1570 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
1571 {
1572 struct listeners *new, *old;
1573 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1574
1575 if (groups < 32)
1576 groups = 32;
1577
1578 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
1579 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
1580 if (!new)
1581 return -ENOMEM;
1582 old = rcu_dereference_protected(tbl->listeners, 1);
1583 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
1584 rcu_assign_pointer(tbl->listeners, new);
1585
1586 kfree_rcu(old, rcu);
1587 }
1588 tbl->groups = groups;
1589
1590 return 0;
1591 }
1592
1593 /**
1594 * netlink_change_ngroups - change number of multicast groups
1595 *
1596 * This changes the number of multicast groups that are available
1597 * on a certain netlink family. Note that it is not possible to
1598 * change the number of groups to below 32. Also note that it does
1599 * not implicitly call netlink_clear_multicast_users() when the
1600 * number of groups is reduced.
1601 *
1602 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
1603 * @groups: The new number of groups.
1604 */
1605 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
1606 {
1607 int err;
1608
1609 netlink_table_grab();
1610 err = __netlink_change_ngroups(sk, groups);
1611 netlink_table_ungrab();
1612
1613 return err;
1614 }
1615
1616 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1617 {
1618 struct sock *sk;
1619 struct hlist_node *node;
1620 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
1621
1622 sk_for_each_bound(sk, node, &tbl->mc_list)
1623 netlink_update_socket_mc(nlk_sk(sk), group, 0);
1624 }
1625
1626 /**
1627 * netlink_clear_multicast_users - kick off multicast listeners
1628 *
1629 * This function removes all listeners from the given group.
1630 * @ksk: The kernel netlink socket, as returned by
1631 * netlink_kernel_create().
1632 * @group: The multicast group to clear.
1633 */
1634 void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
1635 {
1636 netlink_table_grab();
1637 __netlink_clear_multicast_users(ksk, group);
1638 netlink_table_ungrab();
1639 }
1640
1641 void netlink_set_nonroot(int protocol, unsigned int flags)
1642 {
1643 if ((unsigned int)protocol < MAX_LINKS)
1644 nl_table[protocol].nl_nonroot = flags;
1645 }
1646 EXPORT_SYMBOL(netlink_set_nonroot);
1647
1648 static void netlink_destroy_callback(struct netlink_callback *cb)
1649 {
1650 kfree_skb(cb->skb);
1651 kfree(cb);
1652 }
1653
1654 struct nlmsghdr *
1655 __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
1656 {
1657 struct nlmsghdr *nlh;
1658 int size = NLMSG_LENGTH(len);
1659
1660 nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
1661 nlh->nlmsg_type = type;
1662 nlh->nlmsg_len = size;
1663 nlh->nlmsg_flags = flags;
1664 nlh->nlmsg_pid = pid;
1665 nlh->nlmsg_seq = seq;
1666 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
1667 memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size);
1668 return nlh;
1669 }
1670 EXPORT_SYMBOL(__nlmsg_put);
1671
1672 /*
1673 * It looks a bit ugly.
1674 * It would be better to create kernel thread.
1675 */
1676
1677 static int netlink_dump(struct sock *sk)
1678 {
1679 struct netlink_sock *nlk = nlk_sk(sk);
1680 struct netlink_callback *cb;
1681 struct sk_buff *skb = NULL;
1682 struct nlmsghdr *nlh;
1683 int len, err = -ENOBUFS;
1684 int alloc_size;
1685
1686 mutex_lock(nlk->cb_mutex);
1687
1688 cb = nlk->cb;
1689 if (cb == NULL) {
1690 err = -EINVAL;
1691 goto errout_skb;
1692 }
1693
1694 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
1695
1696 skb = sock_rmalloc(sk, alloc_size, 0, GFP_KERNEL);
1697 if (!skb)
1698 goto errout_skb;
1699
1700 len = cb->dump(skb, cb);
1701
1702 if (len > 0) {
1703 mutex_unlock(nlk->cb_mutex);
1704
1705 if (sk_filter(sk, skb))
1706 kfree_skb(skb);
1707 else
1708 __netlink_sendskb(sk, skb);
1709 return 0;
1710 }
1711
1712 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1713 if (!nlh)
1714 goto errout_skb;
1715
1716 nl_dump_check_consistent(cb, nlh);
1717
1718 memcpy(nlmsg_data(nlh), &len, sizeof(len));
1719
1720 if (sk_filter(sk, skb))
1721 kfree_skb(skb);
1722 else
1723 __netlink_sendskb(sk, skb);
1724
1725 if (cb->done)
1726 cb->done(cb);
1727 nlk->cb = NULL;
1728 mutex_unlock(nlk->cb_mutex);
1729
1730 netlink_destroy_callback(cb);
1731 return 0;
1732
1733 errout_skb:
1734 mutex_unlock(nlk->cb_mutex);
1735 kfree_skb(skb);
1736 return err;
1737 }
1738
1739 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1740 const struct nlmsghdr *nlh,
1741 struct netlink_dump_control *control)
1742 {
1743 struct netlink_callback *cb;
1744 struct sock *sk;
1745 struct netlink_sock *nlk;
1746 int ret;
1747
1748 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
1749 if (cb == NULL)
1750 return -ENOBUFS;
1751
1752 cb->dump = control->dump;
1753 cb->done = control->done;
1754 cb->nlh = nlh;
1755 cb->data = control->data;
1756 cb->min_dump_alloc = control->min_dump_alloc;
1757 atomic_inc(&skb->users);
1758 cb->skb = skb;
1759
1760 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).pid);
1761 if (sk == NULL) {
1762 netlink_destroy_callback(cb);
1763 return -ECONNREFUSED;
1764 }
1765 nlk = nlk_sk(sk);
1766 /* A dump is in progress... */
1767 mutex_lock(nlk->cb_mutex);
1768 if (nlk->cb) {
1769 mutex_unlock(nlk->cb_mutex);
1770 netlink_destroy_callback(cb);
1771 sock_put(sk);
1772 return -EBUSY;
1773 }
1774 nlk->cb = cb;
1775 mutex_unlock(nlk->cb_mutex);
1776
1777 ret = netlink_dump(sk);
1778
1779 sock_put(sk);
1780
1781 if (ret)
1782 return ret;
1783
1784 /* We successfully started a dump, by returning -EINTR we
1785 * signal not to send ACK even if it was requested.
1786 */
1787 return -EINTR;
1788 }
1789 EXPORT_SYMBOL(netlink_dump_start);
1790
1791 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1792 {
1793 struct sk_buff *skb;
1794 struct nlmsghdr *rep;
1795 struct nlmsgerr *errmsg;
1796 size_t payload = sizeof(*errmsg);
1797
1798 /* error messages get the original request appened */
1799 if (err)
1800 payload += nlmsg_len(nlh);
1801
1802 skb = nlmsg_new(payload, GFP_KERNEL);
1803 if (!skb) {
1804 struct sock *sk;
1805
1806 sk = netlink_lookup(sock_net(in_skb->sk),
1807 in_skb->sk->sk_protocol,
1808 NETLINK_CB(in_skb).pid);
1809 if (sk) {
1810 sk->sk_err = ENOBUFS;
1811 sk->sk_error_report(sk);
1812 sock_put(sk);
1813 }
1814 return;
1815 }
1816
1817 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1818 NLMSG_ERROR, payload, 0);
1819 errmsg = nlmsg_data(rep);
1820 errmsg->error = err;
1821 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
1822 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1823 }
1824 EXPORT_SYMBOL(netlink_ack);
1825
1826 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
1827 struct nlmsghdr *))
1828 {
1829 struct nlmsghdr *nlh;
1830 int err;
1831
1832 while (skb->len >= nlmsg_total_size(0)) {
1833 int msglen;
1834
1835 nlh = nlmsg_hdr(skb);
1836 err = 0;
1837
1838 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
1839 return 0;
1840
1841 /* Only requests are handled by the kernel */
1842 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
1843 goto ack;
1844
1845 /* Skip control messages */
1846 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
1847 goto ack;
1848
1849 err = cb(skb, nlh);
1850 if (err == -EINTR)
1851 goto skip;
1852
1853 ack:
1854 if (nlh->nlmsg_flags & NLM_F_ACK || err)
1855 netlink_ack(skb, nlh, err);
1856
1857 skip:
1858 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
1859 if (msglen > skb->len)
1860 msglen = skb->len;
1861 skb_pull(skb, msglen);
1862 }
1863
1864 return 0;
1865 }
1866 EXPORT_SYMBOL(netlink_rcv_skb);
1867
1868 /**
1869 * nlmsg_notify - send a notification netlink message
1870 * @sk: netlink socket to use
1871 * @skb: notification message
1872 * @pid: destination netlink pid for reports or 0
1873 * @group: destination multicast group or 0
1874 * @report: 1 to report back, 0 to disable
1875 * @flags: allocation flags
1876 */
1877 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
1878 unsigned int group, int report, gfp_t flags)
1879 {
1880 int err = 0;
1881
1882 if (group) {
1883 int exclude_pid = 0;
1884
1885 if (report) {
1886 atomic_inc(&skb->users);
1887 exclude_pid = pid;
1888 }
1889
1890 /* errors reported via destination sk->sk_err, but propagate
1891 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
1892 err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
1893 }
1894
1895 if (report) {
1896 int err2;
1897
1898 err2 = nlmsg_unicast(sk, skb, pid);
1899 if (!err || err == -ESRCH)
1900 err = err2;
1901 }
1902
1903 return err;
1904 }
1905 EXPORT_SYMBOL(nlmsg_notify);
1906
1907 #ifdef CONFIG_PROC_FS
1908 struct nl_seq_iter {
1909 struct seq_net_private p;
1910 int link;
1911 int hash_idx;
1912 };
1913
1914 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1915 {
1916 struct nl_seq_iter *iter = seq->private;
1917 int i, j;
1918 struct sock *s;
1919 struct hlist_node *node;
1920 loff_t off = 0;
1921
1922 for (i = 0; i < MAX_LINKS; i++) {
1923 struct nl_pid_hash *hash = &nl_table[i].hash;
1924
1925 for (j = 0; j <= hash->mask; j++) {
1926 sk_for_each(s, node, &hash->table[j]) {
1927 if (sock_net(s) != seq_file_net(seq))
1928 continue;
1929 if (off == pos) {
1930 iter->link = i;
1931 iter->hash_idx = j;
1932 return s;
1933 }
1934 ++off;
1935 }
1936 }
1937 }
1938 return NULL;
1939 }
1940
1941 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1942 __acquires(nl_table_lock)
1943 {
1944 read_lock(&nl_table_lock);
1945 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1946 }
1947
1948 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1949 {
1950 struct sock *s;
1951 struct nl_seq_iter *iter;
1952 int i, j;
1953
1954 ++*pos;
1955
1956 if (v == SEQ_START_TOKEN)
1957 return netlink_seq_socket_idx(seq, 0);
1958
1959 iter = seq->private;
1960 s = v;
1961 do {
1962 s = sk_next(s);
1963 } while (s && sock_net(s) != seq_file_net(seq));
1964 if (s)
1965 return s;
1966
1967 i = iter->link;
1968 j = iter->hash_idx + 1;
1969
1970 do {
1971 struct nl_pid_hash *hash = &nl_table[i].hash;
1972
1973 for (; j <= hash->mask; j++) {
1974 s = sk_head(&hash->table[j]);
1975 while (s && sock_net(s) != seq_file_net(seq))
1976 s = sk_next(s);
1977 if (s) {
1978 iter->link = i;
1979 iter->hash_idx = j;
1980 return s;
1981 }
1982 }
1983
1984 j = 0;
1985 } while (++i < MAX_LINKS);
1986
1987 return NULL;
1988 }
1989
1990 static void netlink_seq_stop(struct seq_file *seq, void *v)
1991 __releases(nl_table_lock)
1992 {
1993 read_unlock(&nl_table_lock);
1994 }
1995
1996
1997 static int netlink_seq_show(struct seq_file *seq, void *v)
1998 {
1999 if (v == SEQ_START_TOKEN)
2000 seq_puts(seq,
2001 "sk Eth Pid Groups "
2002 "Rmem Wmem Dump Locks Drops Inode\n");
2003 else {
2004 struct sock *s = v;
2005 struct netlink_sock *nlk = nlk_sk(s);
2006
2007 seq_printf(seq, "%pK %-3d %-6d %08x %-8d %-8d %pK %-8d %-8d %-8lu\n",
2008 s,
2009 s->sk_protocol,
2010 nlk->pid,
2011 nlk->groups ? (u32)nlk->groups[0] : 0,
2012 sk_rmem_alloc_get(s),
2013 sk_wmem_alloc_get(s),
2014 nlk->cb,
2015 atomic_read(&s->sk_refcnt),
2016 atomic_read(&s->sk_drops),
2017 sock_i_ino(s)
2018 );
2019
2020 }
2021 return 0;
2022 }
2023
2024 static const struct seq_operations netlink_seq_ops = {
2025 .start = netlink_seq_start,
2026 .next = netlink_seq_next,
2027 .stop = netlink_seq_stop,
2028 .show = netlink_seq_show,
2029 };
2030
2031
2032 static int netlink_seq_open(struct inode *inode, struct file *file)
2033 {
2034 return seq_open_net(inode, file, &netlink_seq_ops,
2035 sizeof(struct nl_seq_iter));
2036 }
2037
2038 static const struct file_operations netlink_seq_fops = {
2039 .owner = THIS_MODULE,
2040 .open = netlink_seq_open,
2041 .read = seq_read,
2042 .llseek = seq_lseek,
2043 .release = seq_release_net,
2044 };
2045
2046 #endif
2047
2048 int netlink_register_notifier(struct notifier_block *nb)
2049 {
2050 return atomic_notifier_chain_register(&netlink_chain, nb);
2051 }
2052 EXPORT_SYMBOL(netlink_register_notifier);
2053
2054 int netlink_unregister_notifier(struct notifier_block *nb)
2055 {
2056 return atomic_notifier_chain_unregister(&netlink_chain, nb);
2057 }
2058 EXPORT_SYMBOL(netlink_unregister_notifier);
2059
2060 static const struct proto_ops netlink_ops = {
2061 .family = PF_NETLINK,
2062 .owner = THIS_MODULE,
2063 .release = netlink_release,
2064 .bind = netlink_bind,
2065 .connect = netlink_connect,
2066 .socketpair = sock_no_socketpair,
2067 .accept = sock_no_accept,
2068 .getname = netlink_getname,
2069 .poll = datagram_poll,
2070 .ioctl = sock_no_ioctl,
2071 .listen = sock_no_listen,
2072 .shutdown = sock_no_shutdown,
2073 .setsockopt = netlink_setsockopt,
2074 .getsockopt = netlink_getsockopt,
2075 .sendmsg = netlink_sendmsg,
2076 .recvmsg = netlink_recvmsg,
2077 .mmap = sock_no_mmap,
2078 .sendpage = sock_no_sendpage,
2079 };
2080
2081 static const struct net_proto_family netlink_family_ops = {
2082 .family = PF_NETLINK,
2083 .create = netlink_create,
2084 .owner = THIS_MODULE, /* for consistency 8) */
2085 };
2086
2087 static int __net_init netlink_net_init(struct net *net)
2088 {
2089 #ifdef CONFIG_PROC_FS
2090 if (!proc_net_fops_create(net, "netlink", 0, &netlink_seq_fops))
2091 return -ENOMEM;
2092 #endif
2093 return 0;
2094 }
2095
2096 static void __net_exit netlink_net_exit(struct net *net)
2097 {
2098 #ifdef CONFIG_PROC_FS
2099 proc_net_remove(net, "netlink");
2100 #endif
2101 }
2102
2103 static void __init netlink_add_usersock_entry(void)
2104 {
2105 struct listeners *listeners;
2106 int groups = 32;
2107
2108 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2109 if (!listeners)
2110 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2111
2112 netlink_table_grab();
2113
2114 nl_table[NETLINK_USERSOCK].groups = groups;
2115 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
2116 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
2117 nl_table[NETLINK_USERSOCK].registered = 1;
2118
2119 netlink_table_ungrab();
2120 }
2121
2122 static struct pernet_operations __net_initdata netlink_net_ops = {
2123 .init = netlink_net_init,
2124 .exit = netlink_net_exit,
2125 };
2126
2127 static int __init netlink_proto_init(void)
2128 {
2129 struct sk_buff *dummy_skb;
2130 int i;
2131 unsigned long limit;
2132 unsigned int order;
2133 int err = proto_register(&netlink_proto, 0);
2134
2135 if (err != 0)
2136 goto out;
2137
2138 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb));
2139
2140 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
2141 if (!nl_table)
2142 goto panic;
2143
2144 if (totalram_pages >= (128 * 1024))
2145 limit = totalram_pages >> (21 - PAGE_SHIFT);
2146 else
2147 limit = totalram_pages >> (23 - PAGE_SHIFT);
2148
2149 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
2150 limit = (1UL << order) / sizeof(struct hlist_head);
2151 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
2152
2153 for (i = 0; i < MAX_LINKS; i++) {
2154 struct nl_pid_hash *hash = &nl_table[i].hash;
2155
2156 hash->table = nl_pid_hash_zalloc(1 * sizeof(*hash->table));
2157 if (!hash->table) {
2158 while (i-- > 0)
2159 nl_pid_hash_free(nl_table[i].hash.table,
2160 1 * sizeof(*hash->table));
2161 kfree(nl_table);
2162 goto panic;
2163 }
2164 hash->max_shift = order;
2165 hash->shift = 0;
2166 hash->mask = 0;
2167 hash->rehash_time = jiffies;
2168 }
2169
2170 netlink_add_usersock_entry();
2171
2172 sock_register(&netlink_family_ops);
2173 register_pernet_subsys(&netlink_net_ops);
2174 /* The netlink device handler may be needed early. */
2175 rtnetlink_init();
2176 out:
2177 return err;
2178 panic:
2179 panic("netlink_init: Cannot allocate nl_table\n");
2180 }
2181
2182 core_initcall(netlink_proto_init);
Linux 2.6 libata-dev (mirror)