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[deliverable/linux.git] / net / netlink / af_netlink.c
1 /*
2 * NETLINK Kernel-user communication protocol.
3 *
4 * Authors: Alan Cox <alan@redhat.com>
5 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
13 * added netlink_proto_exit
14 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
15 * use nlk_sk, as sk->protinfo is on a diet 8)
16 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
17 * - inc module use count of module that owns
18 * the kernel socket in case userspace opens
19 * socket of same protocol
20 * - remove all module support, since netlink is
21 * mandatory if CONFIG_NET=y these days
22 */
23
24 #include <linux/config.h>
25 #include <linux/module.h>
26
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/signal.h>
30 #include <linux/sched.h>
31 #include <linux/errno.h>
32 #include <linux/string.h>
33 #include <linux/stat.h>
34 #include <linux/socket.h>
35 #include <linux/un.h>
36 #include <linux/fcntl.h>
37 #include <linux/termios.h>
38 #include <linux/sockios.h>
39 #include <linux/net.h>
40 #include <linux/fs.h>
41 #include <linux/slab.h>
42 #include <asm/uaccess.h>
43 #include <linux/skbuff.h>
44 #include <linux/netdevice.h>
45 #include <linux/rtnetlink.h>
46 #include <linux/proc_fs.h>
47 #include <linux/seq_file.h>
48 #include <linux/smp_lock.h>
49 #include <linux/notifier.h>
50 #include <linux/security.h>
51 #include <linux/jhash.h>
52 #include <linux/jiffies.h>
53 #include <linux/random.h>
54 #include <linux/bitops.h>
55 #include <linux/mm.h>
56 #include <linux/types.h>
57 #include <linux/audit.h>
58
59 #include <net/sock.h>
60 #include <net/scm.h>
61
62 #define Nprintk(a...)
63 #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
64
65 struct netlink_sock {
66 /* struct sock has to be the first member of netlink_sock */
67 struct sock sk;
68 u32 pid;
69 u32 dst_pid;
70 u32 dst_group;
71 u32 flags;
72 u32 subscriptions;
73 u32 ngroups;
74 unsigned long *groups;
75 unsigned long state;
76 wait_queue_head_t wait;
77 struct netlink_callback *cb;
78 spinlock_t cb_lock;
79 void (*data_ready)(struct sock *sk, int bytes);
80 struct module *module;
81 };
82
83 #define NETLINK_KERNEL_SOCKET 0x1
84 #define NETLINK_RECV_PKTINFO 0x2
85
86 static inline struct netlink_sock *nlk_sk(struct sock *sk)
87 {
88 return (struct netlink_sock *)sk;
89 }
90
91 struct nl_pid_hash {
92 struct hlist_head *table;
93 unsigned long rehash_time;
94
95 unsigned int mask;
96 unsigned int shift;
97
98 unsigned int entries;
99 unsigned int max_shift;
100
101 u32 rnd;
102 };
103
104 struct netlink_table {
105 struct nl_pid_hash hash;
106 struct hlist_head mc_list;
107 unsigned int nl_nonroot;
108 unsigned int groups;
109 struct module *module;
110 int registered;
111 };
112
113 static struct netlink_table *nl_table;
114
115 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
116
117 static int netlink_dump(struct sock *sk);
118 static void netlink_destroy_callback(struct netlink_callback *cb);
119
120 static DEFINE_RWLOCK(nl_table_lock);
121 static atomic_t nl_table_users = ATOMIC_INIT(0);
122
123 static struct notifier_block *netlink_chain;
124
125 static u32 netlink_group_mask(u32 group)
126 {
127 return group ? 1 << (group - 1) : 0;
128 }
129
130 static struct hlist_head *nl_pid_hashfn(struct nl_pid_hash *hash, u32 pid)
131 {
132 return &hash->table[jhash_1word(pid, hash->rnd) & hash->mask];
133 }
134
135 static void netlink_sock_destruct(struct sock *sk)
136 {
137 skb_queue_purge(&sk->sk_receive_queue);
138
139 if (!sock_flag(sk, SOCK_DEAD)) {
140 printk("Freeing alive netlink socket %p\n", sk);
141 return;
142 }
143 BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
144 BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
145 BUG_TRAP(!nlk_sk(sk)->cb);
146 BUG_TRAP(!nlk_sk(sk)->groups);
147 }
148
149 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on SMP.
150 * Look, when several writers sleep and reader wakes them up, all but one
151 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
152 * this, _but_ remember, it adds useless work on UP machines.
153 */
154
155 static void netlink_table_grab(void)
156 {
157 write_lock_bh(&nl_table_lock);
158
159 if (atomic_read(&nl_table_users)) {
160 DECLARE_WAITQUEUE(wait, current);
161
162 add_wait_queue_exclusive(&nl_table_wait, &wait);
163 for(;;) {
164 set_current_state(TASK_UNINTERRUPTIBLE);
165 if (atomic_read(&nl_table_users) == 0)
166 break;
167 write_unlock_bh(&nl_table_lock);
168 schedule();
169 write_lock_bh(&nl_table_lock);
170 }
171
172 __set_current_state(TASK_RUNNING);
173 remove_wait_queue(&nl_table_wait, &wait);
174 }
175 }
176
177 static __inline__ void netlink_table_ungrab(void)
178 {
179 write_unlock_bh(&nl_table_lock);
180 wake_up(&nl_table_wait);
181 }
182
183 static __inline__ void
184 netlink_lock_table(void)
185 {
186 /* read_lock() synchronizes us to netlink_table_grab */
187
188 read_lock(&nl_table_lock);
189 atomic_inc(&nl_table_users);
190 read_unlock(&nl_table_lock);
191 }
192
193 static __inline__ void
194 netlink_unlock_table(void)
195 {
196 if (atomic_dec_and_test(&nl_table_users))
197 wake_up(&nl_table_wait);
198 }
199
200 static __inline__ struct sock *netlink_lookup(int protocol, u32 pid)
201 {
202 struct nl_pid_hash *hash = &nl_table[protocol].hash;
203 struct hlist_head *head;
204 struct sock *sk;
205 struct hlist_node *node;
206
207 read_lock(&nl_table_lock);
208 head = nl_pid_hashfn(hash, pid);
209 sk_for_each(sk, node, head) {
210 if (nlk_sk(sk)->pid == pid) {
211 sock_hold(sk);
212 goto found;
213 }
214 }
215 sk = NULL;
216 found:
217 read_unlock(&nl_table_lock);
218 return sk;
219 }
220
221 static inline struct hlist_head *nl_pid_hash_alloc(size_t size)
222 {
223 if (size <= PAGE_SIZE)
224 return kmalloc(size, GFP_ATOMIC);
225 else
226 return (struct hlist_head *)
227 __get_free_pages(GFP_ATOMIC, get_order(size));
228 }
229
230 static inline void nl_pid_hash_free(struct hlist_head *table, size_t size)
231 {
232 if (size <= PAGE_SIZE)
233 kfree(table);
234 else
235 free_pages((unsigned long)table, get_order(size));
236 }
237
238 static int nl_pid_hash_rehash(struct nl_pid_hash *hash, int grow)
239 {
240 unsigned int omask, mask, shift;
241 size_t osize, size;
242 struct hlist_head *otable, *table;
243 int i;
244
245 omask = mask = hash->mask;
246 osize = size = (mask + 1) * sizeof(*table);
247 shift = hash->shift;
248
249 if (grow) {
250 if (++shift > hash->max_shift)
251 return 0;
252 mask = mask * 2 + 1;
253 size *= 2;
254 }
255
256 table = nl_pid_hash_alloc(size);
257 if (!table)
258 return 0;
259
260 memset(table, 0, size);
261 otable = hash->table;
262 hash->table = table;
263 hash->mask = mask;
264 hash->shift = shift;
265 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
266
267 for (i = 0; i <= omask; i++) {
268 struct sock *sk;
269 struct hlist_node *node, *tmp;
270
271 sk_for_each_safe(sk, node, tmp, &otable[i])
272 __sk_add_node(sk, nl_pid_hashfn(hash, nlk_sk(sk)->pid));
273 }
274
275 nl_pid_hash_free(otable, osize);
276 hash->rehash_time = jiffies + 10 * 60 * HZ;
277 return 1;
278 }
279
280 static inline int nl_pid_hash_dilute(struct nl_pid_hash *hash, int len)
281 {
282 int avg = hash->entries >> hash->shift;
283
284 if (unlikely(avg > 1) && nl_pid_hash_rehash(hash, 1))
285 return 1;
286
287 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
288 nl_pid_hash_rehash(hash, 0);
289 return 1;
290 }
291
292 return 0;
293 }
294
295 static struct proto_ops netlink_ops;
296
297 static int netlink_insert(struct sock *sk, u32 pid)
298 {
299 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
300 struct hlist_head *head;
301 int err = -EADDRINUSE;
302 struct sock *osk;
303 struct hlist_node *node;
304 int len;
305
306 netlink_table_grab();
307 head = nl_pid_hashfn(hash, pid);
308 len = 0;
309 sk_for_each(osk, node, head) {
310 if (nlk_sk(osk)->pid == pid)
311 break;
312 len++;
313 }
314 if (node)
315 goto err;
316
317 err = -EBUSY;
318 if (nlk_sk(sk)->pid)
319 goto err;
320
321 err = -ENOMEM;
322 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
323 goto err;
324
325 if (len && nl_pid_hash_dilute(hash, len))
326 head = nl_pid_hashfn(hash, pid);
327 hash->entries++;
328 nlk_sk(sk)->pid = pid;
329 sk_add_node(sk, head);
330 err = 0;
331
332 err:
333 netlink_table_ungrab();
334 return err;
335 }
336
337 static void netlink_remove(struct sock *sk)
338 {
339 netlink_table_grab();
340 if (sk_del_node_init(sk))
341 nl_table[sk->sk_protocol].hash.entries--;
342 if (nlk_sk(sk)->subscriptions)
343 __sk_del_bind_node(sk);
344 netlink_table_ungrab();
345 }
346
347 static struct proto netlink_proto = {
348 .name = "NETLINK",
349 .owner = THIS_MODULE,
350 .obj_size = sizeof(struct netlink_sock),
351 };
352
353 static int __netlink_create(struct socket *sock, int protocol)
354 {
355 struct sock *sk;
356 struct netlink_sock *nlk;
357
358 sock->ops = &netlink_ops;
359
360 sk = sk_alloc(PF_NETLINK, GFP_KERNEL, &netlink_proto, 1);
361 if (!sk)
362 return -ENOMEM;
363
364 sock_init_data(sock, sk);
365
366 nlk = nlk_sk(sk);
367 spin_lock_init(&nlk->cb_lock);
368 init_waitqueue_head(&nlk->wait);
369
370 sk->sk_destruct = netlink_sock_destruct;
371 sk->sk_protocol = protocol;
372 return 0;
373 }
374
375 static int netlink_create(struct socket *sock, int protocol)
376 {
377 struct module *module = NULL;
378 struct netlink_sock *nlk;
379 unsigned int groups;
380 int err = 0;
381
382 sock->state = SS_UNCONNECTED;
383
384 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
385 return -ESOCKTNOSUPPORT;
386
387 if (protocol<0 || protocol >= MAX_LINKS)
388 return -EPROTONOSUPPORT;
389
390 netlink_lock_table();
391 #ifdef CONFIG_KMOD
392 if (!nl_table[protocol].registered) {
393 netlink_unlock_table();
394 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
395 netlink_lock_table();
396 }
397 #endif
398 if (nl_table[protocol].registered &&
399 try_module_get(nl_table[protocol].module))
400 module = nl_table[protocol].module;
401 else
402 err = -EPROTONOSUPPORT;
403 groups = nl_table[protocol].groups;
404 netlink_unlock_table();
405
406 if (err || (err = __netlink_create(sock, protocol) < 0))
407 goto out_module;
408
409 nlk = nlk_sk(sock->sk);
410
411 nlk->groups = kmalloc(NLGRPSZ(groups), GFP_KERNEL);
412 if (nlk->groups == NULL) {
413 err = -ENOMEM;
414 goto out_module;
415 }
416 memset(nlk->groups, 0, NLGRPSZ(groups));
417 nlk->ngroups = groups;
418
419 nlk->module = module;
420 out:
421 return err;
422
423 out_module:
424 module_put(module);
425 goto out;
426 }
427
428 static int netlink_release(struct socket *sock)
429 {
430 struct sock *sk = sock->sk;
431 struct netlink_sock *nlk;
432
433 if (!sk)
434 return 0;
435
436 netlink_remove(sk);
437 nlk = nlk_sk(sk);
438
439 spin_lock(&nlk->cb_lock);
440 if (nlk->cb) {
441 nlk->cb->done(nlk->cb);
442 netlink_destroy_callback(nlk->cb);
443 nlk->cb = NULL;
444 }
445 spin_unlock(&nlk->cb_lock);
446
447 /* OK. Socket is unlinked, and, therefore,
448 no new packets will arrive */
449
450 sock_orphan(sk);
451 sock->sk = NULL;
452 wake_up_interruptible_all(&nlk->wait);
453
454 skb_queue_purge(&sk->sk_write_queue);
455
456 if (nlk->pid && !nlk->subscriptions) {
457 struct netlink_notify n = {
458 .protocol = sk->sk_protocol,
459 .pid = nlk->pid,
460 };
461 notifier_call_chain(&netlink_chain, NETLINK_URELEASE, &n);
462 }
463
464 if (nlk->module)
465 module_put(nlk->module);
466
467 if (nlk->flags & NETLINK_KERNEL_SOCKET) {
468 netlink_table_grab();
469 nl_table[sk->sk_protocol].module = NULL;
470 nl_table[sk->sk_protocol].registered = 0;
471 netlink_table_ungrab();
472 }
473
474 kfree(nlk->groups);
475 nlk->groups = NULL;
476
477 sock_put(sk);
478 return 0;
479 }
480
481 static int netlink_autobind(struct socket *sock)
482 {
483 struct sock *sk = sock->sk;
484 struct nl_pid_hash *hash = &nl_table[sk->sk_protocol].hash;
485 struct hlist_head *head;
486 struct sock *osk;
487 struct hlist_node *node;
488 s32 pid = current->pid;
489 int err;
490 static s32 rover = -4097;
491
492 retry:
493 cond_resched();
494 netlink_table_grab();
495 head = nl_pid_hashfn(hash, pid);
496 sk_for_each(osk, node, head) {
497 if (nlk_sk(osk)->pid == pid) {
498 /* Bind collision, search negative pid values. */
499 pid = rover--;
500 if (rover > -4097)
501 rover = -4097;
502 netlink_table_ungrab();
503 goto retry;
504 }
505 }
506 netlink_table_ungrab();
507
508 err = netlink_insert(sk, pid);
509 if (err == -EADDRINUSE)
510 goto retry;
511
512 /* If 2 threads race to autobind, that is fine. */
513 if (err == -EBUSY)
514 err = 0;
515
516 return err;
517 }
518
519 static inline int netlink_capable(struct socket *sock, unsigned int flag)
520 {
521 return (nl_table[sock->sk->sk_protocol].nl_nonroot & flag) ||
522 capable(CAP_NET_ADMIN);
523 }
524
525 static void
526 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
527 {
528 struct netlink_sock *nlk = nlk_sk(sk);
529
530 if (nlk->subscriptions && !subscriptions)
531 __sk_del_bind_node(sk);
532 else if (!nlk->subscriptions && subscriptions)
533 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
534 nlk->subscriptions = subscriptions;
535 }
536
537 static int netlink_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
538 {
539 struct sock *sk = sock->sk;
540 struct netlink_sock *nlk = nlk_sk(sk);
541 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
542 int err;
543
544 if (nladdr->nl_family != AF_NETLINK)
545 return -EINVAL;
546
547 /* Only superuser is allowed to listen multicasts */
548 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_RECV))
549 return -EPERM;
550
551 if (nlk->pid) {
552 if (nladdr->nl_pid != nlk->pid)
553 return -EINVAL;
554 } else {
555 err = nladdr->nl_pid ?
556 netlink_insert(sk, nladdr->nl_pid) :
557 netlink_autobind(sock);
558 if (err)
559 return err;
560 }
561
562 if (!nladdr->nl_groups && !(u32)nlk->groups[0])
563 return 0;
564
565 netlink_table_grab();
566 netlink_update_subscriptions(sk, nlk->subscriptions +
567 hweight32(nladdr->nl_groups) -
568 hweight32(nlk->groups[0]));
569 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
570 netlink_table_ungrab();
571
572 return 0;
573 }
574
575 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
576 int alen, int flags)
577 {
578 int err = 0;
579 struct sock *sk = sock->sk;
580 struct netlink_sock *nlk = nlk_sk(sk);
581 struct sockaddr_nl *nladdr=(struct sockaddr_nl*)addr;
582
583 if (addr->sa_family == AF_UNSPEC) {
584 sk->sk_state = NETLINK_UNCONNECTED;
585 nlk->dst_pid = 0;
586 nlk->dst_group = 0;
587 return 0;
588 }
589 if (addr->sa_family != AF_NETLINK)
590 return -EINVAL;
591
592 /* Only superuser is allowed to send multicasts */
593 if (nladdr->nl_groups && !netlink_capable(sock, NL_NONROOT_SEND))
594 return -EPERM;
595
596 if (!nlk->pid)
597 err = netlink_autobind(sock);
598
599 if (err == 0) {
600 sk->sk_state = NETLINK_CONNECTED;
601 nlk->dst_pid = nladdr->nl_pid;
602 nlk->dst_group = ffs(nladdr->nl_groups);
603 }
604
605 return err;
606 }
607
608 static int netlink_getname(struct socket *sock, struct sockaddr *addr, int *addr_len, int peer)
609 {
610 struct sock *sk = sock->sk;
611 struct netlink_sock *nlk = nlk_sk(sk);
612 struct sockaddr_nl *nladdr=(struct sockaddr_nl *)addr;
613
614 nladdr->nl_family = AF_NETLINK;
615 nladdr->nl_pad = 0;
616 *addr_len = sizeof(*nladdr);
617
618 if (peer) {
619 nladdr->nl_pid = nlk->dst_pid;
620 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
621 } else {
622 nladdr->nl_pid = nlk->pid;
623 nladdr->nl_groups = nlk->groups[0];
624 }
625 return 0;
626 }
627
628 static void netlink_overrun(struct sock *sk)
629 {
630 if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
631 sk->sk_err = ENOBUFS;
632 sk->sk_error_report(sk);
633 }
634 }
635
636 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
637 {
638 int protocol = ssk->sk_protocol;
639 struct sock *sock;
640 struct netlink_sock *nlk;
641
642 sock = netlink_lookup(protocol, pid);
643 if (!sock)
644 return ERR_PTR(-ECONNREFUSED);
645
646 /* Don't bother queuing skb if kernel socket has no input function */
647 nlk = nlk_sk(sock);
648 if ((nlk->pid == 0 && !nlk->data_ready) ||
649 (sock->sk_state == NETLINK_CONNECTED &&
650 nlk->dst_pid != nlk_sk(ssk)->pid)) {
651 sock_put(sock);
652 return ERR_PTR(-ECONNREFUSED);
653 }
654 return sock;
655 }
656
657 struct sock *netlink_getsockbyfilp(struct file *filp)
658 {
659 struct inode *inode = filp->f_dentry->d_inode;
660 struct sock *sock;
661
662 if (!S_ISSOCK(inode->i_mode))
663 return ERR_PTR(-ENOTSOCK);
664
665 sock = SOCKET_I(inode)->sk;
666 if (sock->sk_family != AF_NETLINK)
667 return ERR_PTR(-EINVAL);
668
669 sock_hold(sock);
670 return sock;
671 }
672
673 /*
674 * Attach a skb to a netlink socket.
675 * The caller must hold a reference to the destination socket. On error, the
676 * reference is dropped. The skb is not send to the destination, just all
677 * all error checks are performed and memory in the queue is reserved.
678 * Return values:
679 * < 0: error. skb freed, reference to sock dropped.
680 * 0: continue
681 * 1: repeat lookup - reference dropped while waiting for socket memory.
682 */
683 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, long timeo)
684 {
685 struct netlink_sock *nlk;
686
687 nlk = nlk_sk(sk);
688
689 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
690 test_bit(0, &nlk->state)) {
691 DECLARE_WAITQUEUE(wait, current);
692 if (!timeo) {
693 if (!nlk->pid)
694 netlink_overrun(sk);
695 sock_put(sk);
696 kfree_skb(skb);
697 return -EAGAIN;
698 }
699
700 __set_current_state(TASK_INTERRUPTIBLE);
701 add_wait_queue(&nlk->wait, &wait);
702
703 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
704 test_bit(0, &nlk->state)) &&
705 !sock_flag(sk, SOCK_DEAD))
706 timeo = schedule_timeout(timeo);
707
708 __set_current_state(TASK_RUNNING);
709 remove_wait_queue(&nlk->wait, &wait);
710 sock_put(sk);
711
712 if (signal_pending(current)) {
713 kfree_skb(skb);
714 return sock_intr_errno(timeo);
715 }
716 return 1;
717 }
718 skb_set_owner_r(skb, sk);
719 return 0;
720 }
721
722 int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol)
723 {
724 struct netlink_sock *nlk;
725 int len = skb->len;
726
727 nlk = nlk_sk(sk);
728
729 skb_queue_tail(&sk->sk_receive_queue, skb);
730 sk->sk_data_ready(sk, len);
731 sock_put(sk);
732 return len;
733 }
734
735 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
736 {
737 kfree_skb(skb);
738 sock_put(sk);
739 }
740
741 static inline struct sk_buff *netlink_trim(struct sk_buff *skb,
742 unsigned int __nocast allocation)
743 {
744 int delta;
745
746 skb_orphan(skb);
747
748 delta = skb->end - skb->tail;
749 if (delta * 2 < skb->truesize)
750 return skb;
751
752 if (skb_shared(skb)) {
753 struct sk_buff *nskb = skb_clone(skb, allocation);
754 if (!nskb)
755 return skb;
756 kfree_skb(skb);
757 skb = nskb;
758 }
759
760 if (!pskb_expand_head(skb, 0, -delta, allocation))
761 skb->truesize -= delta;
762
763 return skb;
764 }
765
766 int netlink_unicast(struct sock *ssk, struct sk_buff *skb, u32 pid, int nonblock)
767 {
768 struct sock *sk;
769 int err;
770 long timeo;
771
772 skb = netlink_trim(skb, gfp_any());
773
774 timeo = sock_sndtimeo(ssk, nonblock);
775 retry:
776 sk = netlink_getsockbypid(ssk, pid);
777 if (IS_ERR(sk)) {
778 kfree_skb(skb);
779 return PTR_ERR(sk);
780 }
781 err = netlink_attachskb(sk, skb, nonblock, timeo);
782 if (err == 1)
783 goto retry;
784 if (err)
785 return err;
786
787 return netlink_sendskb(sk, skb, ssk->sk_protocol);
788 }
789
790 static __inline__ int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
791 {
792 struct netlink_sock *nlk = nlk_sk(sk);
793
794 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
795 !test_bit(0, &nlk->state)) {
796 skb_set_owner_r(skb, sk);
797 skb_queue_tail(&sk->sk_receive_queue, skb);
798 sk->sk_data_ready(sk, skb->len);
799 return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
800 }
801 return -1;
802 }
803
804 struct netlink_broadcast_data {
805 struct sock *exclude_sk;
806 u32 pid;
807 u32 group;
808 int failure;
809 int congested;
810 int delivered;
811 unsigned int allocation;
812 struct sk_buff *skb, *skb2;
813 };
814
815 static inline int do_one_broadcast(struct sock *sk,
816 struct netlink_broadcast_data *p)
817 {
818 struct netlink_sock *nlk = nlk_sk(sk);
819 int val;
820
821 if (p->exclude_sk == sk)
822 goto out;
823
824 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
825 !test_bit(p->group - 1, nlk->groups))
826 goto out;
827
828 if (p->failure) {
829 netlink_overrun(sk);
830 goto out;
831 }
832
833 sock_hold(sk);
834 if (p->skb2 == NULL) {
835 if (skb_shared(p->skb)) {
836 p->skb2 = skb_clone(p->skb, p->allocation);
837 } else {
838 p->skb2 = skb_get(p->skb);
839 /*
840 * skb ownership may have been set when
841 * delivered to a previous socket.
842 */
843 skb_orphan(p->skb2);
844 }
845 }
846 if (p->skb2 == NULL) {
847 netlink_overrun(sk);
848 /* Clone failed. Notify ALL listeners. */
849 p->failure = 1;
850 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
851 netlink_overrun(sk);
852 } else {
853 p->congested |= val;
854 p->delivered = 1;
855 p->skb2 = NULL;
856 }
857 sock_put(sk);
858
859 out:
860 return 0;
861 }
862
863 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
864 u32 group, unsigned int __nocast allocation)
865 {
866 struct netlink_broadcast_data info;
867 struct hlist_node *node;
868 struct sock *sk;
869
870 skb = netlink_trim(skb, allocation);
871
872 info.exclude_sk = ssk;
873 info.pid = pid;
874 info.group = group;
875 info.failure = 0;
876 info.congested = 0;
877 info.delivered = 0;
878 info.allocation = allocation;
879 info.skb = skb;
880 info.skb2 = NULL;
881
882 /* While we sleep in clone, do not allow to change socket list */
883
884 netlink_lock_table();
885
886 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
887 do_one_broadcast(sk, &info);
888
889 kfree_skb(skb);
890
891 netlink_unlock_table();
892
893 if (info.skb2)
894 kfree_skb(info.skb2);
895
896 if (info.delivered) {
897 if (info.congested && (allocation & __GFP_WAIT))
898 yield();
899 return 0;
900 }
901 if (info.failure)
902 return -ENOBUFS;
903 return -ESRCH;
904 }
905
906 struct netlink_set_err_data {
907 struct sock *exclude_sk;
908 u32 pid;
909 u32 group;
910 int code;
911 };
912
913 static inline int do_one_set_err(struct sock *sk,
914 struct netlink_set_err_data *p)
915 {
916 struct netlink_sock *nlk = nlk_sk(sk);
917
918 if (sk == p->exclude_sk)
919 goto out;
920
921 if (nlk->pid == p->pid || p->group - 1 >= nlk->ngroups ||
922 !test_bit(p->group - 1, nlk->groups))
923 goto out;
924
925 sk->sk_err = p->code;
926 sk->sk_error_report(sk);
927 out:
928 return 0;
929 }
930
931 void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
932 {
933 struct netlink_set_err_data info;
934 struct hlist_node *node;
935 struct sock *sk;
936
937 info.exclude_sk = ssk;
938 info.pid = pid;
939 info.group = group;
940 info.code = code;
941
942 read_lock(&nl_table_lock);
943
944 sk_for_each_bound(sk, node, &nl_table[ssk->sk_protocol].mc_list)
945 do_one_set_err(sk, &info);
946
947 read_unlock(&nl_table_lock);
948 }
949
950 static int netlink_setsockopt(struct socket *sock, int level, int optname,
951 char __user *optval, int optlen)
952 {
953 struct sock *sk = sock->sk;
954 struct netlink_sock *nlk = nlk_sk(sk);
955 int val = 0, err;
956
957 if (level != SOL_NETLINK)
958 return -ENOPROTOOPT;
959
960 if (optlen >= sizeof(int) &&
961 get_user(val, (int __user *)optval))
962 return -EFAULT;
963
964 switch (optname) {
965 case NETLINK_PKTINFO:
966 if (val)
967 nlk->flags |= NETLINK_RECV_PKTINFO;
968 else
969 nlk->flags &= ~NETLINK_RECV_PKTINFO;
970 err = 0;
971 break;
972 case NETLINK_ADD_MEMBERSHIP:
973 case NETLINK_DROP_MEMBERSHIP: {
974 unsigned int subscriptions;
975 int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0;
976
977 if (!netlink_capable(sock, NL_NONROOT_RECV))
978 return -EPERM;
979 if (!val || val - 1 >= nlk->ngroups)
980 return -EINVAL;
981 netlink_table_grab();
982 old = test_bit(val - 1, nlk->groups);
983 subscriptions = nlk->subscriptions - old + new;
984 if (new)
985 __set_bit(val - 1, nlk->groups);
986 else
987 __clear_bit(val - 1, nlk->groups);
988 netlink_update_subscriptions(sk, subscriptions);
989 netlink_table_ungrab();
990 err = 0;
991 break;
992 }
993 default:
994 err = -ENOPROTOOPT;
995 }
996 return err;
997 }
998
999 static int netlink_getsockopt(struct socket *sock, int level, int optname,
1000 char __user *optval, int __user *optlen)
1001 {
1002 struct sock *sk = sock->sk;
1003 struct netlink_sock *nlk = nlk_sk(sk);
1004 int len, val, err;
1005
1006 if (level != SOL_NETLINK)
1007 return -ENOPROTOOPT;
1008
1009 if (get_user(len, optlen))
1010 return -EFAULT;
1011 if (len < 0)
1012 return -EINVAL;
1013
1014 switch (optname) {
1015 case NETLINK_PKTINFO:
1016 if (len < sizeof(int))
1017 return -EINVAL;
1018 len = sizeof(int);
1019 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
1020 put_user(len, optlen);
1021 put_user(val, optval);
1022 err = 0;
1023 break;
1024 default:
1025 err = -ENOPROTOOPT;
1026 }
1027 return err;
1028 }
1029
1030 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
1031 {
1032 struct nl_pktinfo info;
1033
1034 info.group = NETLINK_CB(skb).dst_group;
1035 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
1036 }
1037
1038 static inline void netlink_rcv_wake(struct sock *sk)
1039 {
1040 struct netlink_sock *nlk = nlk_sk(sk);
1041
1042 if (skb_queue_empty(&sk->sk_receive_queue))
1043 clear_bit(0, &nlk->state);
1044 if (!test_bit(0, &nlk->state))
1045 wake_up_interruptible(&nlk->wait);
1046 }
1047
1048 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
1049 struct msghdr *msg, size_t len)
1050 {
1051 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1052 struct sock *sk = sock->sk;
1053 struct netlink_sock *nlk = nlk_sk(sk);
1054 struct sockaddr_nl *addr=msg->msg_name;
1055 u32 dst_pid;
1056 u32 dst_group;
1057 struct sk_buff *skb;
1058 int err;
1059 struct scm_cookie scm;
1060
1061 if (msg->msg_flags&MSG_OOB)
1062 return -EOPNOTSUPP;
1063
1064 if (NULL == siocb->scm)
1065 siocb->scm = &scm;
1066 err = scm_send(sock, msg, siocb->scm);
1067 if (err < 0)
1068 return err;
1069
1070 if (msg->msg_namelen) {
1071 if (addr->nl_family != AF_NETLINK)
1072 return -EINVAL;
1073 dst_pid = addr->nl_pid;
1074 dst_group = ffs(addr->nl_groups);
1075 if (dst_group && !netlink_capable(sock, NL_NONROOT_SEND))
1076 return -EPERM;
1077 } else {
1078 dst_pid = nlk->dst_pid;
1079 dst_group = nlk->dst_group;
1080 }
1081
1082 if (!nlk->pid) {
1083 err = netlink_autobind(sock);
1084 if (err)
1085 goto out;
1086 }
1087
1088 err = -EMSGSIZE;
1089 if (len > sk->sk_sndbuf - 32)
1090 goto out;
1091 err = -ENOBUFS;
1092 skb = alloc_skb(len, GFP_KERNEL);
1093 if (skb==NULL)
1094 goto out;
1095
1096 NETLINK_CB(skb).pid = nlk->pid;
1097 NETLINK_CB(skb).dst_pid = dst_pid;
1098 NETLINK_CB(skb).dst_group = dst_group;
1099 NETLINK_CB(skb).loginuid = audit_get_loginuid(current->audit_context);
1100 memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
1101
1102 /* What can I do? Netlink is asynchronous, so that
1103 we will have to save current capabilities to
1104 check them, when this message will be delivered
1105 to corresponding kernel module. --ANK (980802)
1106 */
1107
1108 err = -EFAULT;
1109 if (memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len)) {
1110 kfree_skb(skb);
1111 goto out;
1112 }
1113
1114 err = security_netlink_send(sk, skb);
1115 if (err) {
1116 kfree_skb(skb);
1117 goto out;
1118 }
1119
1120 if (dst_group) {
1121 atomic_inc(&skb->users);
1122 netlink_broadcast(sk, skb, dst_pid, dst_group, GFP_KERNEL);
1123 }
1124 err = netlink_unicast(sk, skb, dst_pid, msg->msg_flags&MSG_DONTWAIT);
1125
1126 out:
1127 return err;
1128 }
1129
1130 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
1131 struct msghdr *msg, size_t len,
1132 int flags)
1133 {
1134 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
1135 struct scm_cookie scm;
1136 struct sock *sk = sock->sk;
1137 struct netlink_sock *nlk = nlk_sk(sk);
1138 int noblock = flags&MSG_DONTWAIT;
1139 size_t copied;
1140 struct sk_buff *skb;
1141 int err;
1142
1143 if (flags&MSG_OOB)
1144 return -EOPNOTSUPP;
1145
1146 copied = 0;
1147
1148 skb = skb_recv_datagram(sk,flags,noblock,&err);
1149 if (skb==NULL)
1150 goto out;
1151
1152 msg->msg_namelen = 0;
1153
1154 copied = skb->len;
1155 if (len < copied) {
1156 msg->msg_flags |= MSG_TRUNC;
1157 copied = len;
1158 }
1159
1160 skb->h.raw = skb->data;
1161 err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
1162
1163 if (msg->msg_name) {
1164 struct sockaddr_nl *addr = (struct sockaddr_nl*)msg->msg_name;
1165 addr->nl_family = AF_NETLINK;
1166 addr->nl_pad = 0;
1167 addr->nl_pid = NETLINK_CB(skb).pid;
1168 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
1169 msg->msg_namelen = sizeof(*addr);
1170 }
1171
1172 if (NULL == siocb->scm) {
1173 memset(&scm, 0, sizeof(scm));
1174 siocb->scm = &scm;
1175 }
1176 siocb->scm->creds = *NETLINK_CREDS(skb);
1177 skb_free_datagram(sk, skb);
1178
1179 if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2)
1180 netlink_dump(sk);
1181
1182 scm_recv(sock, msg, siocb->scm, flags);
1183 if (nlk->flags & NETLINK_RECV_PKTINFO)
1184 netlink_cmsg_recv_pktinfo(msg, skb);
1185
1186 out:
1187 netlink_rcv_wake(sk);
1188 return err ? : copied;
1189 }
1190
1191 static void netlink_data_ready(struct sock *sk, int len)
1192 {
1193 struct netlink_sock *nlk = nlk_sk(sk);
1194
1195 if (nlk->data_ready)
1196 nlk->data_ready(sk, len);
1197 netlink_rcv_wake(sk);
1198 }
1199
1200 /*
1201 * We export these functions to other modules. They provide a
1202 * complete set of kernel non-blocking support for message
1203 * queueing.
1204 */
1205
1206 struct sock *
1207 netlink_kernel_create(int unit, unsigned int groups,
1208 void (*input)(struct sock *sk, int len),
1209 struct module *module)
1210 {
1211 struct socket *sock;
1212 struct sock *sk;
1213 struct netlink_sock *nlk;
1214
1215 if (!nl_table)
1216 return NULL;
1217
1218 if (unit<0 || unit>=MAX_LINKS)
1219 return NULL;
1220
1221 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
1222 return NULL;
1223
1224 if (__netlink_create(sock, unit) < 0)
1225 goto out_sock_release;
1226
1227 sk = sock->sk;
1228 sk->sk_data_ready = netlink_data_ready;
1229 if (input)
1230 nlk_sk(sk)->data_ready = input;
1231
1232 if (netlink_insert(sk, 0))
1233 goto out_sock_release;
1234
1235 nlk = nlk_sk(sk);
1236 nlk->flags |= NETLINK_KERNEL_SOCKET;
1237
1238 netlink_table_grab();
1239 nl_table[unit].groups = groups < 32 ? 32 : groups;
1240 nl_table[unit].module = module;
1241 nl_table[unit].registered = 1;
1242 netlink_table_ungrab();
1243
1244 return sk;
1245
1246 out_sock_release:
1247 sock_release(sock);
1248 return NULL;
1249 }
1250
1251 void netlink_set_nonroot(int protocol, unsigned int flags)
1252 {
1253 if ((unsigned int)protocol < MAX_LINKS)
1254 nl_table[protocol].nl_nonroot = flags;
1255 }
1256
1257 static void netlink_destroy_callback(struct netlink_callback *cb)
1258 {
1259 if (cb->skb)
1260 kfree_skb(cb->skb);
1261 kfree(cb);
1262 }
1263
1264 /*
1265 * It looks a bit ugly.
1266 * It would be better to create kernel thread.
1267 */
1268
1269 static int netlink_dump(struct sock *sk)
1270 {
1271 struct netlink_sock *nlk = nlk_sk(sk);
1272 struct netlink_callback *cb;
1273 struct sk_buff *skb;
1274 struct nlmsghdr *nlh;
1275 int len;
1276
1277 skb = sock_rmalloc(sk, NLMSG_GOODSIZE, 0, GFP_KERNEL);
1278 if (!skb)
1279 return -ENOBUFS;
1280
1281 spin_lock(&nlk->cb_lock);
1282
1283 cb = nlk->cb;
1284 if (cb == NULL) {
1285 spin_unlock(&nlk->cb_lock);
1286 kfree_skb(skb);
1287 return -EINVAL;
1288 }
1289
1290 len = cb->dump(skb, cb);
1291
1292 if (len > 0) {
1293 spin_unlock(&nlk->cb_lock);
1294 skb_queue_tail(&sk->sk_receive_queue, skb);
1295 sk->sk_data_ready(sk, len);
1296 return 0;
1297 }
1298
1299 nlh = NLMSG_NEW_ANSWER(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
1300 memcpy(NLMSG_DATA(nlh), &len, sizeof(len));
1301 skb_queue_tail(&sk->sk_receive_queue, skb);
1302 sk->sk_data_ready(sk, skb->len);
1303
1304 cb->done(cb);
1305 nlk->cb = NULL;
1306 spin_unlock(&nlk->cb_lock);
1307
1308 netlink_destroy_callback(cb);
1309 return 0;
1310
1311 nlmsg_failure:
1312 return -ENOBUFS;
1313 }
1314
1315 int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
1316 struct nlmsghdr *nlh,
1317 int (*dump)(struct sk_buff *skb, struct netlink_callback*),
1318 int (*done)(struct netlink_callback*))
1319 {
1320 struct netlink_callback *cb;
1321 struct sock *sk;
1322 struct netlink_sock *nlk;
1323
1324 cb = kmalloc(sizeof(*cb), GFP_KERNEL);
1325 if (cb == NULL)
1326 return -ENOBUFS;
1327
1328 memset(cb, 0, sizeof(*cb));
1329 cb->dump = dump;
1330 cb->done = done;
1331 cb->nlh = nlh;
1332 atomic_inc(&skb->users);
1333 cb->skb = skb;
1334
1335 sk = netlink_lookup(ssk->sk_protocol, NETLINK_CB(skb).pid);
1336 if (sk == NULL) {
1337 netlink_destroy_callback(cb);
1338 return -ECONNREFUSED;
1339 }
1340 nlk = nlk_sk(sk);
1341 /* A dump is in progress... */
1342 spin_lock(&nlk->cb_lock);
1343 if (nlk->cb) {
1344 spin_unlock(&nlk->cb_lock);
1345 netlink_destroy_callback(cb);
1346 sock_put(sk);
1347 return -EBUSY;
1348 }
1349 nlk->cb = cb;
1350 spin_unlock(&nlk->cb_lock);
1351
1352 netlink_dump(sk);
1353 sock_put(sk);
1354 return 0;
1355 }
1356
1357 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
1358 {
1359 struct sk_buff *skb;
1360 struct nlmsghdr *rep;
1361 struct nlmsgerr *errmsg;
1362 int size;
1363
1364 if (err == 0)
1365 size = NLMSG_SPACE(sizeof(struct nlmsgerr));
1366 else
1367 size = NLMSG_SPACE(4 + NLMSG_ALIGN(nlh->nlmsg_len));
1368
1369 skb = alloc_skb(size, GFP_KERNEL);
1370 if (!skb) {
1371 struct sock *sk;
1372
1373 sk = netlink_lookup(in_skb->sk->sk_protocol,
1374 NETLINK_CB(in_skb).pid);
1375 if (sk) {
1376 sk->sk_err = ENOBUFS;
1377 sk->sk_error_report(sk);
1378 sock_put(sk);
1379 }
1380 return;
1381 }
1382
1383 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq,
1384 NLMSG_ERROR, sizeof(struct nlmsgerr), 0);
1385 errmsg = NLMSG_DATA(rep);
1386 errmsg->error = err;
1387 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(struct nlmsghdr));
1388 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1389 }
1390
1391
1392 #ifdef CONFIG_PROC_FS
1393 struct nl_seq_iter {
1394 int link;
1395 int hash_idx;
1396 };
1397
1398 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
1399 {
1400 struct nl_seq_iter *iter = seq->private;
1401 int i, j;
1402 struct sock *s;
1403 struct hlist_node *node;
1404 loff_t off = 0;
1405
1406 for (i=0; i<MAX_LINKS; i++) {
1407 struct nl_pid_hash *hash = &nl_table[i].hash;
1408
1409 for (j = 0; j <= hash->mask; j++) {
1410 sk_for_each(s, node, &hash->table[j]) {
1411 if (off == pos) {
1412 iter->link = i;
1413 iter->hash_idx = j;
1414 return s;
1415 }
1416 ++off;
1417 }
1418 }
1419 }
1420 return NULL;
1421 }
1422
1423 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
1424 {
1425 read_lock(&nl_table_lock);
1426 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
1427 }
1428
1429 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1430 {
1431 struct sock *s;
1432 struct nl_seq_iter *iter;
1433 int i, j;
1434
1435 ++*pos;
1436
1437 if (v == SEQ_START_TOKEN)
1438 return netlink_seq_socket_idx(seq, 0);
1439
1440 s = sk_next(v);
1441 if (s)
1442 return s;
1443
1444 iter = seq->private;
1445 i = iter->link;
1446 j = iter->hash_idx + 1;
1447
1448 do {
1449 struct nl_pid_hash *hash = &nl_table[i].hash;
1450
1451 for (; j <= hash->mask; j++) {
1452 s = sk_head(&hash->table[j]);
1453 if (s) {
1454 iter->link = i;
1455 iter->hash_idx = j;
1456 return s;
1457 }
1458 }
1459
1460 j = 0;
1461 } while (++i < MAX_LINKS);
1462
1463 return NULL;
1464 }
1465
1466 static void netlink_seq_stop(struct seq_file *seq, void *v)
1467 {
1468 read_unlock(&nl_table_lock);
1469 }
1470
1471
1472 static int netlink_seq_show(struct seq_file *seq, void *v)
1473 {
1474 if (v == SEQ_START_TOKEN)
1475 seq_puts(seq,
1476 "sk Eth Pid Groups "
1477 "Rmem Wmem Dump Locks\n");
1478 else {
1479 struct sock *s = v;
1480 struct netlink_sock *nlk = nlk_sk(s);
1481
1482 seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
1483 s,
1484 s->sk_protocol,
1485 nlk->pid,
1486 nlk->flags & NETLINK_KERNEL_SOCKET ?
1487 0 : (unsigned int)nlk->groups[0],
1488 atomic_read(&s->sk_rmem_alloc),
1489 atomic_read(&s->sk_wmem_alloc),
1490 nlk->cb,
1491 atomic_read(&s->sk_refcnt)
1492 );
1493
1494 }
1495 return 0;
1496 }
1497
1498 static struct seq_operations netlink_seq_ops = {
1499 .start = netlink_seq_start,
1500 .next = netlink_seq_next,
1501 .stop = netlink_seq_stop,
1502 .show = netlink_seq_show,
1503 };
1504
1505
1506 static int netlink_seq_open(struct inode *inode, struct file *file)
1507 {
1508 struct seq_file *seq;
1509 struct nl_seq_iter *iter;
1510 int err;
1511
1512 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
1513 if (!iter)
1514 return -ENOMEM;
1515
1516 err = seq_open(file, &netlink_seq_ops);
1517 if (err) {
1518 kfree(iter);
1519 return err;
1520 }
1521
1522 memset(iter, 0, sizeof(*iter));
1523 seq = file->private_data;
1524 seq->private = iter;
1525 return 0;
1526 }
1527
1528 static struct file_operations netlink_seq_fops = {
1529 .owner = THIS_MODULE,
1530 .open = netlink_seq_open,
1531 .read = seq_read,
1532 .llseek = seq_lseek,
1533 .release = seq_release_private,
1534 };
1535
1536 #endif
1537
1538 int netlink_register_notifier(struct notifier_block *nb)
1539 {
1540 return notifier_chain_register(&netlink_chain, nb);
1541 }
1542
1543 int netlink_unregister_notifier(struct notifier_block *nb)
1544 {
1545 return notifier_chain_unregister(&netlink_chain, nb);
1546 }
1547
1548 static struct proto_ops netlink_ops = {
1549 .family = PF_NETLINK,
1550 .owner = THIS_MODULE,
1551 .release = netlink_release,
1552 .bind = netlink_bind,
1553 .connect = netlink_connect,
1554 .socketpair = sock_no_socketpair,
1555 .accept = sock_no_accept,
1556 .getname = netlink_getname,
1557 .poll = datagram_poll,
1558 .ioctl = sock_no_ioctl,
1559 .listen = sock_no_listen,
1560 .shutdown = sock_no_shutdown,
1561 .setsockopt = netlink_setsockopt,
1562 .getsockopt = netlink_getsockopt,
1563 .sendmsg = netlink_sendmsg,
1564 .recvmsg = netlink_recvmsg,
1565 .mmap = sock_no_mmap,
1566 .sendpage = sock_no_sendpage,
1567 };
1568
1569 static struct net_proto_family netlink_family_ops = {
1570 .family = PF_NETLINK,
1571 .create = netlink_create,
1572 .owner = THIS_MODULE, /* for consistency 8) */
1573 };
1574
1575 extern void netlink_skb_parms_too_large(void);
1576
1577 static int __init netlink_proto_init(void)
1578 {
1579 struct sk_buff *dummy_skb;
1580 int i;
1581 unsigned long max;
1582 unsigned int order;
1583 int err = proto_register(&netlink_proto, 0);
1584
1585 if (err != 0)
1586 goto out;
1587
1588 if (sizeof(struct netlink_skb_parms) > sizeof(dummy_skb->cb))
1589 netlink_skb_parms_too_large();
1590
1591 nl_table = kmalloc(sizeof(*nl_table) * MAX_LINKS, GFP_KERNEL);
1592 if (!nl_table) {
1593 enomem:
1594 printk(KERN_CRIT "netlink_init: Cannot allocate nl_table\n");
1595 return -ENOMEM;
1596 }
1597
1598 memset(nl_table, 0, sizeof(*nl_table) * MAX_LINKS);
1599
1600 if (num_physpages >= (128 * 1024))
1601 max = num_physpages >> (21 - PAGE_SHIFT);
1602 else
1603 max = num_physpages >> (23 - PAGE_SHIFT);
1604
1605 order = get_bitmask_order(max) - 1 + PAGE_SHIFT;
1606 max = (1UL << order) / sizeof(struct hlist_head);
1607 order = get_bitmask_order(max > UINT_MAX ? UINT_MAX : max) - 1;
1608
1609 for (i = 0; i < MAX_LINKS; i++) {
1610 struct nl_pid_hash *hash = &nl_table[i].hash;
1611
1612 hash->table = nl_pid_hash_alloc(1 * sizeof(*hash->table));
1613 if (!hash->table) {
1614 while (i-- > 0)
1615 nl_pid_hash_free(nl_table[i].hash.table,
1616 1 * sizeof(*hash->table));
1617 kfree(nl_table);
1618 goto enomem;
1619 }
1620 memset(hash->table, 0, 1 * sizeof(*hash->table));
1621 hash->max_shift = order;
1622 hash->shift = 0;
1623 hash->mask = 0;
1624 hash->rehash_time = jiffies;
1625 }
1626
1627 sock_register(&netlink_family_ops);
1628 #ifdef CONFIG_PROC_FS
1629 proc_net_fops_create("netlink", 0, &netlink_seq_fops);
1630 #endif
1631 /* The netlink device handler may be needed early. */
1632 rtnetlink_init();
1633 out:
1634 return err;
1635 }
1636
1637 core_initcall(netlink_proto_init);
1638
1639 EXPORT_SYMBOL(netlink_ack);
1640 EXPORT_SYMBOL(netlink_broadcast);
1641 EXPORT_SYMBOL(netlink_dump_start);
1642 EXPORT_SYMBOL(netlink_kernel_create);
1643 EXPORT_SYMBOL(netlink_register_notifier);
1644 EXPORT_SYMBOL(netlink_set_err);
1645 EXPORT_SYMBOL(netlink_set_nonroot);
1646 EXPORT_SYMBOL(netlink_unicast);
1647 EXPORT_SYMBOL(netlink_unregister_notifier);
1648
Linux kernel - Deliverables
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