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dmaengine: edma: Add support for DMA_PAUSE/RESUME operation
[linux-2.6/btrfs-unstable.git] / net / netlink / af_netlink.c
blob894cda0206bb9b8a32488ec81959482a7cc582d5
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 * Patrick McHardy <kaber@trash.net>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 *
13 * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
14 * added netlink_proto_exit
15 * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
16 * use nlk_sk, as sk->protinfo is on a diet 8)
17 * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
18 * - inc module use count of module that owns
19 * the kernel socket in case userspace opens
20 * socket of same protocol
21 * - remove all module support, since netlink is
22 * mandatory if CONFIG_NET=y these days
23 */
24
25 #include <linux/module.h>
26
27 #include <linux/capability.h>
28 #include <linux/kernel.h>
29 #include <linux/init.h>
30 #include <linux/signal.h>
31 #include <linux/sched.h>
32 #include <linux/errno.h>
33 #include <linux/string.h>
34 #include <linux/stat.h>
35 #include <linux/socket.h>
36 #include <linux/un.h>
37 #include <linux/fcntl.h>
38 #include <linux/termios.h>
39 #include <linux/sockios.h>
40 #include <linux/net.h>
41 #include <linux/fs.h>
42 #include <linux/slab.h>
43 #include <asm/uaccess.h>
44 #include <linux/skbuff.h>
45 #include <linux/netdevice.h>
46 #include <linux/rtnetlink.h>
47 #include <linux/proc_fs.h>
48 #include <linux/seq_file.h>
49 #include <linux/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 #include <linux/mutex.h>
59 #include <linux/vmalloc.h>
60 #include <linux/if_arp.h>
61 #include <asm/cacheflush.h>
62
63 #include <net/net_namespace.h>
64 #include <net/sock.h>
65 #include <net/scm.h>
66 #include <net/netlink.h>
67
68 #include "af_netlink.h"
69
70 struct listeners {
71 struct rcu_head rcu;
72 unsigned long masks[0];
73 };
74
75 /* state bits */
76 #define NETLINK_CONGESTED 0x0
77
78 /* flags */
79 #define NETLINK_KERNEL_SOCKET 0x1
80 #define NETLINK_RECV_PKTINFO 0x2
81 #define NETLINK_BROADCAST_SEND_ERROR 0x4
82 #define NETLINK_RECV_NO_ENOBUFS 0x8
83
84 static inline int netlink_is_kernel(struct sock *sk)
85 {
86 return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
87 }
88
89 struct netlink_table *nl_table;
90 EXPORT_SYMBOL_GPL(nl_table);
91
92 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
93
94 static int netlink_dump(struct sock *sk);
95 static void netlink_skb_destructor(struct sk_buff *skb);
96
97 DEFINE_RWLOCK(nl_table_lock);
98 EXPORT_SYMBOL_GPL(nl_table_lock);
99 static atomic_t nl_table_users = ATOMIC_INIT(0);
100
101 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
102
103 static ATOMIC_NOTIFIER_HEAD(netlink_chain);
104
105 static DEFINE_SPINLOCK(netlink_tap_lock);
106 static struct list_head netlink_tap_all __read_mostly;
107
108 static inline u32 netlink_group_mask(u32 group)
109 {
110 return group ? 1 << (group - 1) : 0;
111 }
112
113 static inline struct hlist_head *nl_portid_hashfn(struct nl_portid_hash *hash, u32 portid)
114 {
115 return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask];
116 }
117
118 int netlink_add_tap(struct netlink_tap *nt)
119 {
120 if (unlikely(nt->dev->type != ARPHRD_NETLINK))
121 return -EINVAL;
122
123 spin_lock(&netlink_tap_lock);
124 list_add_rcu(&nt->list, &netlink_tap_all);
125 spin_unlock(&netlink_tap_lock);
126
127 if (nt->module)
128 __module_get(nt->module);
129
130 return 0;
131 }
132 EXPORT_SYMBOL_GPL(netlink_add_tap);
133
134 static int __netlink_remove_tap(struct netlink_tap *nt)
135 {
136 bool found = false;
137 struct netlink_tap *tmp;
138
139 spin_lock(&netlink_tap_lock);
140
141 list_for_each_entry(tmp, &netlink_tap_all, list) {
142 if (nt == tmp) {
143 list_del_rcu(&nt->list);
144 found = true;
145 goto out;
146 }
147 }
148
149 pr_warn("__netlink_remove_tap: %p not found\n", nt);
150 out:
151 spin_unlock(&netlink_tap_lock);
152
153 if (found && nt->module)
154 module_put(nt->module);
155
156 return found ? 0 : -ENODEV;
157 }
158
159 int netlink_remove_tap(struct netlink_tap *nt)
160 {
161 int ret;
162
163 ret = __netlink_remove_tap(nt);
164 synchronize_net();
165
166 return ret;
167 }
168 EXPORT_SYMBOL_GPL(netlink_remove_tap);
169
170 static bool netlink_filter_tap(const struct sk_buff *skb)
171 {
172 struct sock *sk = skb->sk;
173 bool pass = false;
174
175 /* We take the more conservative approach and
176 * whitelist socket protocols that may pass.
177 */
178 switch (sk->sk_protocol) {
179 case NETLINK_ROUTE:
180 case NETLINK_USERSOCK:
181 case NETLINK_SOCK_DIAG:
182 case NETLINK_NFLOG:
183 case NETLINK_XFRM:
184 case NETLINK_FIB_LOOKUP:
185 case NETLINK_NETFILTER:
186 case NETLINK_GENERIC:
187 pass = true;
188 break;
189 }
190
191 return pass;
192 }
193
194 static int __netlink_deliver_tap_skb(struct sk_buff *skb,
195 struct net_device *dev)
196 {
197 struct sk_buff *nskb;
198 struct sock *sk = skb->sk;
199 int ret = -ENOMEM;
200
201 dev_hold(dev);
202 nskb = skb_clone(skb, GFP_ATOMIC);
203 if (nskb) {
204 nskb->dev = dev;
205 nskb->protocol = htons((u16) sk->sk_protocol);
206 nskb->pkt_type = netlink_is_kernel(sk) ?
207 PACKET_KERNEL : PACKET_USER;
208
209 ret = dev_queue_xmit(nskb);
210 if (unlikely(ret > 0))
211 ret = net_xmit_errno(ret);
212 }
213
214 dev_put(dev);
215 return ret;
216 }
217
218 static void __netlink_deliver_tap(struct sk_buff *skb)
219 {
220 int ret;
221 struct netlink_tap *tmp;
222
223 if (!netlink_filter_tap(skb))
224 return;
225
226 list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
227 ret = __netlink_deliver_tap_skb(skb, tmp->dev);
228 if (unlikely(ret))
229 break;
230 }
231 }
232
233 static void netlink_deliver_tap(struct sk_buff *skb)
234 {
235 rcu_read_lock();
236
237 if (unlikely(!list_empty(&netlink_tap_all)))
238 __netlink_deliver_tap(skb);
239
240 rcu_read_unlock();
241 }
242
243 static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
244 struct sk_buff *skb)
245 {
246 if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
247 netlink_deliver_tap(skb);
248 }
249
250 static void netlink_overrun(struct sock *sk)
251 {
252 struct netlink_sock *nlk = nlk_sk(sk);
253
254 if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
255 if (!test_and_set_bit(NETLINK_CONGESTED, &nlk_sk(sk)->state)) {
256 sk->sk_err = ENOBUFS;
257 sk->sk_error_report(sk);
258 }
259 }
260 atomic_inc(&sk->sk_drops);
261 }
262
263 static void netlink_rcv_wake(struct sock *sk)
264 {
265 struct netlink_sock *nlk = nlk_sk(sk);
266
267 if (skb_queue_empty(&sk->sk_receive_queue))
268 clear_bit(NETLINK_CONGESTED, &nlk->state);
269 if (!test_bit(NETLINK_CONGESTED, &nlk->state))
270 wake_up_interruptible(&nlk->wait);
271 }
272
273 #ifdef CONFIG_NETLINK_MMAP
274 static bool netlink_skb_is_mmaped(const struct sk_buff *skb)
275 {
276 return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED;
277 }
278
279 static bool netlink_rx_is_mmaped(struct sock *sk)
280 {
281 return nlk_sk(sk)->rx_ring.pg_vec != NULL;
282 }
283
284 static bool netlink_tx_is_mmaped(struct sock *sk)
285 {
286 return nlk_sk(sk)->tx_ring.pg_vec != NULL;
287 }
288
289 static __pure struct page *pgvec_to_page(const void *addr)
290 {
291 if (is_vmalloc_addr(addr))
292 return vmalloc_to_page(addr);
293 else
294 return virt_to_page(addr);
295 }
296
297 static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len)
298 {
299 unsigned int i;
300
301 for (i = 0; i < len; i++) {
302 if (pg_vec[i] != NULL) {
303 if (is_vmalloc_addr(pg_vec[i]))
304 vfree(pg_vec[i]);
305 else
306 free_pages((unsigned long)pg_vec[i], order);
307 }
308 }
309 kfree(pg_vec);
310 }
311
312 static void *alloc_one_pg_vec_page(unsigned long order)
313 {
314 void *buffer;
315 gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO |
316 __GFP_NOWARN | __GFP_NORETRY;
317
318 buffer = (void *)__get_free_pages(gfp_flags, order);
319 if (buffer != NULL)
320 return buffer;
321
322 buffer = vzalloc((1 << order) * PAGE_SIZE);
323 if (buffer != NULL)
324 return buffer;
325
326 gfp_flags &= ~__GFP_NORETRY;
327 return (void *)__get_free_pages(gfp_flags, order);
328 }
329
330 static void **alloc_pg_vec(struct netlink_sock *nlk,
331 struct nl_mmap_req *req, unsigned int order)
332 {
333 unsigned int block_nr = req->nm_block_nr;
334 unsigned int i;
335 void **pg_vec;
336
337 pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL);
338 if (pg_vec == NULL)
339 return NULL;
340
341 for (i = 0; i < block_nr; i++) {
342 pg_vec[i] = alloc_one_pg_vec_page(order);
343 if (pg_vec[i] == NULL)
344 goto err1;
345 }
346
347 return pg_vec;
348 err1:
349 free_pg_vec(pg_vec, order, block_nr);
350 return NULL;
351 }
352
353 static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req,
354 bool closing, bool tx_ring)
355 {
356 struct netlink_sock *nlk = nlk_sk(sk);
357 struct netlink_ring *ring;
358 struct sk_buff_head *queue;
359 void **pg_vec = NULL;
360 unsigned int order = 0;
361 int err;
362
363 ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring;
364 queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
365
366 if (!closing) {
367 if (atomic_read(&nlk->mapped))
368 return -EBUSY;
369 if (atomic_read(&ring->pending))
370 return -EBUSY;
371 }
372
373 if (req->nm_block_nr) {
374 if (ring->pg_vec != NULL)
375 return -EBUSY;
376
377 if ((int)req->nm_block_size <= 0)
378 return -EINVAL;
379 if (!IS_ALIGNED(req->nm_block_size, PAGE_SIZE))
380 return -EINVAL;
381 if (req->nm_frame_size < NL_MMAP_HDRLEN)
382 return -EINVAL;
383 if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT))
384 return -EINVAL;
385
386 ring->frames_per_block = req->nm_block_size /
387 req->nm_frame_size;
388 if (ring->frames_per_block == 0)
389 return -EINVAL;
390 if (ring->frames_per_block * req->nm_block_nr !=
391 req->nm_frame_nr)
392 return -EINVAL;
393
394 order = get_order(req->nm_block_size);
395 pg_vec = alloc_pg_vec(nlk, req, order);
396 if (pg_vec == NULL)
397 return -ENOMEM;
398 } else {
399 if (req->nm_frame_nr)
400 return -EINVAL;
401 }
402
403 err = -EBUSY;
404 mutex_lock(&nlk->pg_vec_lock);
405 if (closing || atomic_read(&nlk->mapped) == 0) {
406 err = 0;
407 spin_lock_bh(&queue->lock);
408
409 ring->frame_max = req->nm_frame_nr - 1;
410 ring->head = 0;
411 ring->frame_size = req->nm_frame_size;
412 ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE;
413
414 swap(ring->pg_vec_len, req->nm_block_nr);
415 swap(ring->pg_vec_order, order);
416 swap(ring->pg_vec, pg_vec);
417
418 __skb_queue_purge(queue);
419 spin_unlock_bh(&queue->lock);
420
421 WARN_ON(atomic_read(&nlk->mapped));
422 }
423 mutex_unlock(&nlk->pg_vec_lock);
424
425 if (pg_vec)
426 free_pg_vec(pg_vec, order, req->nm_block_nr);
427 return err;
428 }
429
430 static void netlink_mm_open(struct vm_area_struct *vma)
431 {
432 struct file *file = vma->vm_file;
433 struct socket *sock = file->private_data;
434 struct sock *sk = sock->sk;
435
436 if (sk)
437 atomic_inc(&nlk_sk(sk)->mapped);
438 }
439
440 static void netlink_mm_close(struct vm_area_struct *vma)
441 {
442 struct file *file = vma->vm_file;
443 struct socket *sock = file->private_data;
444 struct sock *sk = sock->sk;
445
446 if (sk)
447 atomic_dec(&nlk_sk(sk)->mapped);
448 }
449
450 static const struct vm_operations_struct netlink_mmap_ops = {
451 .open = netlink_mm_open,
452 .close = netlink_mm_close,
453 };
454
455 static int netlink_mmap(struct file *file, struct socket *sock,
456 struct vm_area_struct *vma)
457 {
458 struct sock *sk = sock->sk;
459 struct netlink_sock *nlk = nlk_sk(sk);
460 struct netlink_ring *ring;
461 unsigned long start, size, expected;
462 unsigned int i;
463 int err = -EINVAL;
464
465 if (vma->vm_pgoff)
466 return -EINVAL;
467
468 mutex_lock(&nlk->pg_vec_lock);
469
470 expected = 0;
471 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
472 if (ring->pg_vec == NULL)
473 continue;
474 expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE;
475 }
476
477 if (expected == 0)
478 goto out;
479
480 size = vma->vm_end - vma->vm_start;
481 if (size != expected)
482 goto out;
483
484 start = vma->vm_start;
485 for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
486 if (ring->pg_vec == NULL)
487 continue;
488
489 for (i = 0; i < ring->pg_vec_len; i++) {
490 struct page *page;
491 void *kaddr = ring->pg_vec[i];
492 unsigned int pg_num;
493
494 for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) {
495 page = pgvec_to_page(kaddr);
496 err = vm_insert_page(vma, start, page);
497 if (err < 0)
498 goto out;
499 start += PAGE_SIZE;
500 kaddr += PAGE_SIZE;
501 }
502 }
503 }
504
505 atomic_inc(&nlk->mapped);
506 vma->vm_ops = &netlink_mmap_ops;
507 err = 0;
508 out:
509 mutex_unlock(&nlk->pg_vec_lock);
510 return err;
511 }
512
513 static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr)
514 {
515 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
516 struct page *p_start, *p_end;
517
518 /* First page is flushed through netlink_{get,set}_status */
519 p_start = pgvec_to_page(hdr + PAGE_SIZE);
520 p_end = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + hdr->nm_len - 1);
521 while (p_start <= p_end) {
522 flush_dcache_page(p_start);
523 p_start++;
524 }
525 #endif
526 }
527
528 static enum nl_mmap_status netlink_get_status(const struct nl_mmap_hdr *hdr)
529 {
530 smp_rmb();
531 flush_dcache_page(pgvec_to_page(hdr));
532 return hdr->nm_status;
533 }
534
535 static void netlink_set_status(struct nl_mmap_hdr *hdr,
536 enum nl_mmap_status status)
537 {
538 hdr->nm_status = status;
539 flush_dcache_page(pgvec_to_page(hdr));
540 smp_wmb();
541 }
542
543 static struct nl_mmap_hdr *
544 __netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos)
545 {
546 unsigned int pg_vec_pos, frame_off;
547
548 pg_vec_pos = pos / ring->frames_per_block;
549 frame_off = pos % ring->frames_per_block;
550
551 return ring->pg_vec[pg_vec_pos] + (frame_off * ring->frame_size);
552 }
553
554 static struct nl_mmap_hdr *
555 netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos,
556 enum nl_mmap_status status)
557 {
558 struct nl_mmap_hdr *hdr;
559
560 hdr = __netlink_lookup_frame(ring, pos);
561 if (netlink_get_status(hdr) != status)
562 return NULL;
563
564 return hdr;
565 }
566
567 static struct nl_mmap_hdr *
568 netlink_current_frame(const struct netlink_ring *ring,
569 enum nl_mmap_status status)
570 {
571 return netlink_lookup_frame(ring, ring->head, status);
572 }
573
574 static struct nl_mmap_hdr *
575 netlink_previous_frame(const struct netlink_ring *ring,
576 enum nl_mmap_status status)
577 {
578 unsigned int prev;
579
580 prev = ring->head ? ring->head - 1 : ring->frame_max;
581 return netlink_lookup_frame(ring, prev, status);
582 }
583
584 static void netlink_increment_head(struct netlink_ring *ring)
585 {
586 ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0;
587 }
588
589 static void netlink_forward_ring(struct netlink_ring *ring)
590 {
591 unsigned int head = ring->head, pos = head;
592 const struct nl_mmap_hdr *hdr;
593
594 do {
595 hdr = __netlink_lookup_frame(ring, pos);
596 if (hdr->nm_status == NL_MMAP_STATUS_UNUSED)
597 break;
598 if (hdr->nm_status != NL_MMAP_STATUS_SKIP)
599 break;
600 netlink_increment_head(ring);
601 } while (ring->head != head);
602 }
603
604 static bool netlink_dump_space(struct netlink_sock *nlk)
605 {
606 struct netlink_ring *ring = &nlk->rx_ring;
607 struct nl_mmap_hdr *hdr;
608 unsigned int n;
609
610 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
611 if (hdr == NULL)
612 return false;
613
614 n = ring->head + ring->frame_max / 2;
615 if (n > ring->frame_max)
616 n -= ring->frame_max;
617
618 hdr = __netlink_lookup_frame(ring, n);
619
620 return hdr->nm_status == NL_MMAP_STATUS_UNUSED;
621 }
622
623 static unsigned int netlink_poll(struct file *file, struct socket *sock,
624 poll_table *wait)
625 {
626 struct sock *sk = sock->sk;
627 struct netlink_sock *nlk = nlk_sk(sk);
628 unsigned int mask;
629 int err;
630
631 if (nlk->rx_ring.pg_vec != NULL) {
632 /* Memory mapped sockets don't call recvmsg(), so flow control
633 * for dumps is performed here. A dump is allowed to continue
634 * if at least half the ring is unused.
635 */
636 while (nlk->cb_running && netlink_dump_space(nlk)) {
637 err = netlink_dump(sk);
638 if (err < 0) {
639 sk->sk_err = err;
640 sk->sk_error_report(sk);
641 break;
642 }
643 }
644 netlink_rcv_wake(sk);
645 }
646
647 mask = datagram_poll(file, sock, wait);
648
649 spin_lock_bh(&sk->sk_receive_queue.lock);
650 if (nlk->rx_ring.pg_vec) {
651 netlink_forward_ring(&nlk->rx_ring);
652 if (!netlink_previous_frame(&nlk->rx_ring, NL_MMAP_STATUS_UNUSED))
653 mask |= POLLIN | POLLRDNORM;
654 }
655 spin_unlock_bh(&sk->sk_receive_queue.lock);
656
657 spin_lock_bh(&sk->sk_write_queue.lock);
658 if (nlk->tx_ring.pg_vec) {
659 if (netlink_current_frame(&nlk->tx_ring, NL_MMAP_STATUS_UNUSED))
660 mask |= POLLOUT | POLLWRNORM;
661 }
662 spin_unlock_bh(&sk->sk_write_queue.lock);
663
664 return mask;
665 }
666
667 static struct nl_mmap_hdr *netlink_mmap_hdr(struct sk_buff *skb)
668 {
669 return (struct nl_mmap_hdr *)(skb->head - NL_MMAP_HDRLEN);
670 }
671
672 static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
673 struct netlink_ring *ring,
674 struct nl_mmap_hdr *hdr)
675 {
676 unsigned int size;
677 void *data;
678
679 size = ring->frame_size - NL_MMAP_HDRLEN;
680 data = (void *)hdr + NL_MMAP_HDRLEN;
681
682 skb->head = data;
683 skb->data = data;
684 skb_reset_tail_pointer(skb);
685 skb->end = skb->tail + size;
686 skb->len = 0;
687
688 skb->destructor = netlink_skb_destructor;
689 NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED;
690 NETLINK_CB(skb).sk = sk;
691 }
692
693 static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
694 u32 dst_portid, u32 dst_group,
695 struct sock_iocb *siocb)
696 {
697 struct netlink_sock *nlk = nlk_sk(sk);
698 struct netlink_ring *ring;
699 struct nl_mmap_hdr *hdr;
700 struct sk_buff *skb;
701 unsigned int maxlen;
702 bool excl = true;
703 int err = 0, len = 0;
704
705 /* Netlink messages are validated by the receiver before processing.
706 * In order to avoid userspace changing the contents of the message
707 * after validation, the socket and the ring may only be used by a
708 * single process, otherwise we fall back to copying.
709 */
710 if (atomic_long_read(&sk->sk_socket->file->f_count) > 2 ||
711 atomic_read(&nlk->mapped) > 1)
712 excl = false;
713
714 mutex_lock(&nlk->pg_vec_lock);
715
716 ring = &nlk->tx_ring;
717 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
718
719 do {
720 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
721 if (hdr == NULL) {
722 if (!(msg->msg_flags & MSG_DONTWAIT) &&
723 atomic_read(&nlk->tx_ring.pending))
724 schedule();
725 continue;
726 }
727 if (hdr->nm_len > maxlen) {
728 err = -EINVAL;
729 goto out;
730 }
731
732 netlink_frame_flush_dcache(hdr);
733
734 if (likely(dst_portid == 0 && dst_group == 0 && excl)) {
735 skb = alloc_skb_head(GFP_KERNEL);
736 if (skb == NULL) {
737 err = -ENOBUFS;
738 goto out;
739 }
740 sock_hold(sk);
741 netlink_ring_setup_skb(skb, sk, ring, hdr);
742 NETLINK_CB(skb).flags |= NETLINK_SKB_TX;
743 __skb_put(skb, hdr->nm_len);
744 netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
745 atomic_inc(&ring->pending);
746 } else {
747 skb = alloc_skb(hdr->nm_len, GFP_KERNEL);
748 if (skb == NULL) {
749 err = -ENOBUFS;
750 goto out;
751 }
752 __skb_put(skb, hdr->nm_len);
753 memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len);
754 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
755 }
756
757 netlink_increment_head(ring);
758
759 NETLINK_CB(skb).portid = nlk->portid;
760 NETLINK_CB(skb).dst_group = dst_group;
761 NETLINK_CB(skb).creds = siocb->scm->creds;
762
763 err = security_netlink_send(sk, skb);
764 if (err) {
765 kfree_skb(skb);
766 goto out;
767 }
768
769 if (unlikely(dst_group)) {
770 atomic_inc(&skb->users);
771 netlink_broadcast(sk, skb, dst_portid, dst_group,
772 GFP_KERNEL);
773 }
774 err = netlink_unicast(sk, skb, dst_portid,
775 msg->msg_flags & MSG_DONTWAIT);
776 if (err < 0)
777 goto out;
778 len += err;
779
780 } while (hdr != NULL ||
781 (!(msg->msg_flags & MSG_DONTWAIT) &&
782 atomic_read(&nlk->tx_ring.pending)));
783
784 if (len > 0)
785 err = len;
786 out:
787 mutex_unlock(&nlk->pg_vec_lock);
788 return err;
789 }
790
791 static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb)
792 {
793 struct nl_mmap_hdr *hdr;
794
795 hdr = netlink_mmap_hdr(skb);
796 hdr->nm_len = skb->len;
797 hdr->nm_group = NETLINK_CB(skb).dst_group;
798 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
799 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
800 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
801 netlink_frame_flush_dcache(hdr);
802 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
803
804 NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED;
805 kfree_skb(skb);
806 }
807
808 static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb)
809 {
810 struct netlink_sock *nlk = nlk_sk(sk);
811 struct netlink_ring *ring = &nlk->rx_ring;
812 struct nl_mmap_hdr *hdr;
813
814 spin_lock_bh(&sk->sk_receive_queue.lock);
815 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
816 if (hdr == NULL) {
817 spin_unlock_bh(&sk->sk_receive_queue.lock);
818 kfree_skb(skb);
819 netlink_overrun(sk);
820 return;
821 }
822 netlink_increment_head(ring);
823 __skb_queue_tail(&sk->sk_receive_queue, skb);
824 spin_unlock_bh(&sk->sk_receive_queue.lock);
825
826 hdr->nm_len = skb->len;
827 hdr->nm_group = NETLINK_CB(skb).dst_group;
828 hdr->nm_pid = NETLINK_CB(skb).creds.pid;
829 hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
830 hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
831 netlink_set_status(hdr, NL_MMAP_STATUS_COPY);
832 }
833
834 #else /* CONFIG_NETLINK_MMAP */
835 #define netlink_skb_is_mmaped(skb) false
836 #define netlink_rx_is_mmaped(sk) false
837 #define netlink_tx_is_mmaped(sk) false
838 #define netlink_mmap sock_no_mmap
839 #define netlink_poll datagram_poll
840 #define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0
841 #endif /* CONFIG_NETLINK_MMAP */
842
843 static void netlink_skb_destructor(struct sk_buff *skb)
844 {
845 #ifdef CONFIG_NETLINK_MMAP
846 struct nl_mmap_hdr *hdr;
847 struct netlink_ring *ring;
848 struct sock *sk;
849
850 /* If a packet from the kernel to userspace was freed because of an
851 * error without being delivered to userspace, the kernel must reset
852 * the status. In the direction userspace to kernel, the status is
853 * always reset here after the packet was processed and freed.
854 */
855 if (netlink_skb_is_mmaped(skb)) {
856 hdr = netlink_mmap_hdr(skb);
857 sk = NETLINK_CB(skb).sk;
858
859 if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) {
860 netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
861 ring = &nlk_sk(sk)->tx_ring;
862 } else {
863 if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
864 hdr->nm_len = 0;
865 netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
866 }
867 ring = &nlk_sk(sk)->rx_ring;
868 }
869
870 WARN_ON(atomic_read(&ring->pending) == 0);
871 atomic_dec(&ring->pending);
872 sock_put(sk);
873
874 skb->head = NULL;
875 }
876 #endif
877 if (is_vmalloc_addr(skb->head)) {
878 if (!skb->cloned ||
879 !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
880 vfree(skb->head);
881
882 skb->head = NULL;
883 }
884 if (skb->sk != NULL)
885 sock_rfree(skb);
886 }
887
888 static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
889 {
890 WARN_ON(skb->sk != NULL);
891 skb->sk = sk;
892 skb->destructor = netlink_skb_destructor;
893 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
894 sk_mem_charge(sk, skb->truesize);
895 }
896
897 static void netlink_sock_destruct(struct sock *sk)
898 {
899 struct netlink_sock *nlk = nlk_sk(sk);
900
901 if (nlk->cb_running) {
902 if (nlk->cb.done)
903 nlk->cb.done(&nlk->cb);
904
905 module_put(nlk->cb.module);
906 kfree_skb(nlk->cb.skb);
907 }
908
909 skb_queue_purge(&sk->sk_receive_queue);
910 #ifdef CONFIG_NETLINK_MMAP
911 if (1) {
912 struct nl_mmap_req req;
913
914 memset(&req, 0, sizeof(req));
915 if (nlk->rx_ring.pg_vec)
916 netlink_set_ring(sk, &req, true, false);
917 memset(&req, 0, sizeof(req));
918 if (nlk->tx_ring.pg_vec)
919 netlink_set_ring(sk, &req, true, true);
920 }
921 #endif /* CONFIG_NETLINK_MMAP */
922
923 if (!sock_flag(sk, SOCK_DEAD)) {
924 printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
925 return;
926 }
927
928 WARN_ON(atomic_read(&sk->sk_rmem_alloc));
929 WARN_ON(atomic_read(&sk->sk_wmem_alloc));
930 WARN_ON(nlk_sk(sk)->groups);
931 }
932
933 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
934 * SMP. Look, when several writers sleep and reader wakes them up, all but one
935 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
936 * this, _but_ remember, it adds useless work on UP machines.
937 */
938
939 void netlink_table_grab(void)
940 __acquires(nl_table_lock)
941 {
942 might_sleep();
943
944 write_lock_irq(&nl_table_lock);
945
946 if (atomic_read(&nl_table_users)) {
947 DECLARE_WAITQUEUE(wait, current);
948
949 add_wait_queue_exclusive(&nl_table_wait, &wait);
950 for (;;) {
951 set_current_state(TASK_UNINTERRUPTIBLE);
952 if (atomic_read(&nl_table_users) == 0)
953 break;
954 write_unlock_irq(&nl_table_lock);
955 schedule();
956 write_lock_irq(&nl_table_lock);
957 }
958
959 __set_current_state(TASK_RUNNING);
960 remove_wait_queue(&nl_table_wait, &wait);
961 }
962 }
963
964 void netlink_table_ungrab(void)
965 __releases(nl_table_lock)
966 {
967 write_unlock_irq(&nl_table_lock);
968 wake_up(&nl_table_wait);
969 }
970
971 static inline void
972 netlink_lock_table(void)
973 {
974 /* read_lock() synchronizes us to netlink_table_grab */
975
976 read_lock(&nl_table_lock);
977 atomic_inc(&nl_table_users);
978 read_unlock(&nl_table_lock);
979 }
980
981 static inline void
982 netlink_unlock_table(void)
983 {
984 if (atomic_dec_and_test(&nl_table_users))
985 wake_up(&nl_table_wait);
986 }
987
988 static bool netlink_compare(struct net *net, struct sock *sk)
989 {
990 return net_eq(sock_net(sk), net);
991 }
992
993 static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
994 {
995 struct netlink_table *table = &nl_table[protocol];
996 struct nl_portid_hash *hash = &table->hash;
997 struct hlist_head *head;
998 struct sock *sk;
999
1000 read_lock(&nl_table_lock);
1001 head = nl_portid_hashfn(hash, portid);
1002 sk_for_each(sk, head) {
1003 if (table->compare(net, sk) &&
1004 (nlk_sk(sk)->portid == portid)) {
1005 sock_hold(sk);
1006 goto found;
1007 }
1008 }
1009 sk = NULL;
1010 found:
1011 read_unlock(&nl_table_lock);
1012 return sk;
1013 }
1014
1015 static struct hlist_head *nl_portid_hash_zalloc(size_t size)
1016 {
1017 if (size <= PAGE_SIZE)
1018 return kzalloc(size, GFP_ATOMIC);
1019 else
1020 return (struct hlist_head *)
1021 __get_free_pages(GFP_ATOMIC | __GFP_ZERO,
1022 get_order(size));
1023 }
1024
1025 static void nl_portid_hash_free(struct hlist_head *table, size_t size)
1026 {
1027 if (size <= PAGE_SIZE)
1028 kfree(table);
1029 else
1030 free_pages((unsigned long)table, get_order(size));
1031 }
1032
1033 static int nl_portid_hash_rehash(struct nl_portid_hash *hash, int grow)
1034 {
1035 unsigned int omask, mask, shift;
1036 size_t osize, size;
1037 struct hlist_head *otable, *table;
1038 int i;
1039
1040 omask = mask = hash->mask;
1041 osize = size = (mask + 1) * sizeof(*table);
1042 shift = hash->shift;
1043
1044 if (grow) {
1045 if (++shift > hash->max_shift)
1046 return 0;
1047 mask = mask * 2 + 1;
1048 size *= 2;
1049 }
1050
1051 table = nl_portid_hash_zalloc(size);
1052 if (!table)
1053 return 0;
1054
1055 otable = hash->table;
1056 hash->table = table;
1057 hash->mask = mask;
1058 hash->shift = shift;
1059 get_random_bytes(&hash->rnd, sizeof(hash->rnd));
1060
1061 for (i = 0; i <= omask; i++) {
1062 struct sock *sk;
1063 struct hlist_node *tmp;
1064
1065 sk_for_each_safe(sk, tmp, &otable[i])
1066 __sk_add_node(sk, nl_portid_hashfn(hash, nlk_sk(sk)->portid));
1067 }
1068
1069 nl_portid_hash_free(otable, osize);
1070 hash->rehash_time = jiffies + 10 * 60 * HZ;
1071 return 1;
1072 }
1073
1074 static inline int nl_portid_hash_dilute(struct nl_portid_hash *hash, int len)
1075 {
1076 int avg = hash->entries >> hash->shift;
1077
1078 if (unlikely(avg > 1) && nl_portid_hash_rehash(hash, 1))
1079 return 1;
1080
1081 if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
1082 nl_portid_hash_rehash(hash, 0);
1083 return 1;
1084 }
1085
1086 return 0;
1087 }
1088
1089 static const struct proto_ops netlink_ops;
1090
1091 static void
1092 netlink_update_listeners(struct sock *sk)
1093 {
1094 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
1095 unsigned long mask;
1096 unsigned int i;
1097 struct listeners *listeners;
1098
1099 listeners = nl_deref_protected(tbl->listeners);
1100 if (!listeners)
1101 return;
1102
1103 for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
1104 mask = 0;
1105 sk_for_each_bound(sk, &tbl->mc_list) {
1106 if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
1107 mask |= nlk_sk(sk)->groups[i];
1108 }
1109 listeners->masks[i] = mask;
1110 }
1111 /* this function is only called with the netlink table "grabbed", which
1112 * makes sure updates are visible before bind or setsockopt return. */
1113 }
1114
1115 static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
1116 {
1117 struct netlink_table *table = &nl_table[sk->sk_protocol];
1118 struct nl_portid_hash *hash = &table->hash;
1119 struct hlist_head *head;
1120 int err = -EADDRINUSE;
1121 struct sock *osk;
1122 int len;
1123
1124 netlink_table_grab();
1125 head = nl_portid_hashfn(hash, portid);
1126 len = 0;
1127 sk_for_each(osk, head) {
1128 if (table->compare(net, osk) &&
1129 (nlk_sk(osk)->portid == portid))
1130 break;
1131 len++;
1132 }
1133 if (osk)
1134 goto err;
1135
1136 err = -EBUSY;
1137 if (nlk_sk(sk)->portid)
1138 goto err;
1139
1140 err = -ENOMEM;
1141 if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
1142 goto err;
1143
1144 if (len && nl_portid_hash_dilute(hash, len))
1145 head = nl_portid_hashfn(hash, portid);
1146 hash->entries++;
1147 nlk_sk(sk)->portid = portid;
1148 sk_add_node(sk, head);
1149 err = 0;
1150
1151 err:
1152 netlink_table_ungrab();
1153 return err;
1154 }
1155
1156 static void netlink_remove(struct sock *sk)
1157 {
1158 netlink_table_grab();
1159 if (sk_del_node_init(sk))
1160 nl_table[sk->sk_protocol].hash.entries--;
1161 if (nlk_sk(sk)->subscriptions)
1162 __sk_del_bind_node(sk);
1163 netlink_table_ungrab();
1164 }
1165
1166 static struct proto netlink_proto = {
1167 .name = "NETLINK",
1168 .owner = THIS_MODULE,
1169 .obj_size = sizeof(struct netlink_sock),
1170 };
1171
1172 static int __netlink_create(struct net *net, struct socket *sock,
1173 struct mutex *cb_mutex, int protocol)
1174 {
1175 struct sock *sk;
1176 struct netlink_sock *nlk;
1177
1178 sock->ops = &netlink_ops;
1179
1180 sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
1181 if (!sk)
1182 return -ENOMEM;
1183
1184 sock_init_data(sock, sk);
1185
1186 nlk = nlk_sk(sk);
1187 if (cb_mutex) {
1188 nlk->cb_mutex = cb_mutex;
1189 } else {
1190 nlk->cb_mutex = &nlk->cb_def_mutex;
1191 mutex_init(nlk->cb_mutex);
1192 }
1193 init_waitqueue_head(&nlk->wait);
1194 #ifdef CONFIG_NETLINK_MMAP
1195 mutex_init(&nlk->pg_vec_lock);
1196 #endif
1197
1198 sk->sk_destruct = netlink_sock_destruct;
1199 sk->sk_protocol = protocol;
1200 return 0;
1201 }
1202
1203 static int netlink_create(struct net *net, struct socket *sock, int protocol,
1204 int kern)
1205 {
1206 struct module *module = NULL;
1207 struct mutex *cb_mutex;
1208 struct netlink_sock *nlk;
1209 void (*bind)(int group);
1210 int err = 0;
1211
1212 sock->state = SS_UNCONNECTED;
1213
1214 if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
1215 return -ESOCKTNOSUPPORT;
1216
1217 if (protocol < 0 || protocol >= MAX_LINKS)
1218 return -EPROTONOSUPPORT;
1219
1220 netlink_lock_table();
1221 #ifdef CONFIG_MODULES
1222 if (!nl_table[protocol].registered) {
1223 netlink_unlock_table();
1224 request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
1225 netlink_lock_table();
1226 }
1227 #endif
1228 if (nl_table[protocol].registered &&
1229 try_module_get(nl_table[protocol].module))
1230 module = nl_table[protocol].module;
1231 else
1232 err = -EPROTONOSUPPORT;
1233 cb_mutex = nl_table[protocol].cb_mutex;
1234 bind = nl_table[protocol].bind;
1235 netlink_unlock_table();
1236
1237 if (err < 0)
1238 goto out;
1239
1240 err = __netlink_create(net, sock, cb_mutex, protocol);
1241 if (err < 0)
1242 goto out_module;
1243
1244 local_bh_disable();
1245 sock_prot_inuse_add(net, &netlink_proto, 1);
1246 local_bh_enable();
1247
1248 nlk = nlk_sk(sock->sk);
1249 nlk->module = module;
1250 nlk->netlink_bind = bind;
1251 out:
1252 return err;
1253
1254 out_module:
1255 module_put(module);
1256 goto out;
1257 }
1258
1259 static int netlink_release(struct socket *sock)
1260 {
1261 struct sock *sk = sock->sk;
1262 struct netlink_sock *nlk;
1263
1264 if (!sk)
1265 return 0;
1266
1267 netlink_remove(sk);
1268 sock_orphan(sk);
1269 nlk = nlk_sk(sk);
1270
1271 /*
1272 * OK. Socket is unlinked, any packets that arrive now
1273 * will be purged.
1274 */
1275
1276 sock->sk = NULL;
1277 wake_up_interruptible_all(&nlk->wait);
1278
1279 skb_queue_purge(&sk->sk_write_queue);
1280
1281 if (nlk->portid) {
1282 struct netlink_notify n = {
1283 .net = sock_net(sk),
1284 .protocol = sk->sk_protocol,
1285 .portid = nlk->portid,
1286 };
1287 atomic_notifier_call_chain(&netlink_chain,
1288 NETLINK_URELEASE, &n);
1289 }
1290
1291 module_put(nlk->module);
1292
1293 netlink_table_grab();
1294 if (netlink_is_kernel(sk)) {
1295 BUG_ON(nl_table[sk->sk_protocol].registered == 0);
1296 if (--nl_table[sk->sk_protocol].registered == 0) {
1297 struct listeners *old;
1298
1299 old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
1300 RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
1301 kfree_rcu(old, rcu);
1302 nl_table[sk->sk_protocol].module = NULL;
1303 nl_table[sk->sk_protocol].bind = NULL;
1304 nl_table[sk->sk_protocol].flags = 0;
1305 nl_table[sk->sk_protocol].registered = 0;
1306 }
1307 } else if (nlk->subscriptions) {
1308 netlink_update_listeners(sk);
1309 }
1310 netlink_table_ungrab();
1311
1312 kfree(nlk->groups);
1313 nlk->groups = NULL;
1314
1315 local_bh_disable();
1316 sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
1317 local_bh_enable();
1318 sock_put(sk);
1319 return 0;
1320 }
1321
1322 static int netlink_autobind(struct socket *sock)
1323 {
1324 struct sock *sk = sock->sk;
1325 struct net *net = sock_net(sk);
1326 struct netlink_table *table = &nl_table[sk->sk_protocol];
1327 struct nl_portid_hash *hash = &table->hash;
1328 struct hlist_head *head;
1329 struct sock *osk;
1330 s32 portid = task_tgid_vnr(current);
1331 int err;
1332 static s32 rover = -4097;
1333
1334 retry:
1335 cond_resched();
1336 netlink_table_grab();
1337 head = nl_portid_hashfn(hash, portid);
1338 sk_for_each(osk, head) {
1339 if (!table->compare(net, osk))
1340 continue;
1341 if (nlk_sk(osk)->portid == portid) {
1342 /* Bind collision, search negative portid values. */
1343 portid = rover--;
1344 if (rover > -4097)
1345 rover = -4097;
1346 netlink_table_ungrab();
1347 goto retry;
1348 }
1349 }
1350 netlink_table_ungrab();
1351
1352 err = netlink_insert(sk, net, portid);
1353 if (err == -EADDRINUSE)
1354 goto retry;
1355
1356 /* If 2 threads race to autobind, that is fine. */
1357 if (err == -EBUSY)
1358 err = 0;
1359
1360 return err;
1361 }
1362
1363 static inline int netlink_capable(const struct socket *sock, unsigned int flag)
1364 {
1365 return (nl_table[sock->sk->sk_protocol].flags & flag) ||
1366 ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
1367 }
1368
1369 static void
1370 netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
1371 {
1372 struct netlink_sock *nlk = nlk_sk(sk);
1373
1374 if (nlk->subscriptions && !subscriptions)
1375 __sk_del_bind_node(sk);
1376 else if (!nlk->subscriptions && subscriptions)
1377 sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
1378 nlk->subscriptions = subscriptions;
1379 }
1380
1381 static int netlink_realloc_groups(struct sock *sk)
1382 {
1383 struct netlink_sock *nlk = nlk_sk(sk);
1384 unsigned int groups;
1385 unsigned long *new_groups;
1386 int err = 0;
1387
1388 netlink_table_grab();
1389
1390 groups = nl_table[sk->sk_protocol].groups;
1391 if (!nl_table[sk->sk_protocol].registered) {
1392 err = -ENOENT;
1393 goto out_unlock;
1394 }
1395
1396 if (nlk->ngroups >= groups)
1397 goto out_unlock;
1398
1399 new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
1400 if (new_groups == NULL) {
1401 err = -ENOMEM;
1402 goto out_unlock;
1403 }
1404 memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
1405 NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
1406
1407 nlk->groups = new_groups;
1408 nlk->ngroups = groups;
1409 out_unlock:
1410 netlink_table_ungrab();
1411 return err;
1412 }
1413
1414 static int netlink_bind(struct socket *sock, struct sockaddr *addr,
1415 int addr_len)
1416 {
1417 struct sock *sk = sock->sk;
1418 struct net *net = sock_net(sk);
1419 struct netlink_sock *nlk = nlk_sk(sk);
1420 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1421 int err;
1422
1423 if (addr_len < sizeof(struct sockaddr_nl))
1424 return -EINVAL;
1425
1426 if (nladdr->nl_family != AF_NETLINK)
1427 return -EINVAL;
1428
1429 /* Only superuser is allowed to listen multicasts */
1430 if (nladdr->nl_groups) {
1431 if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV))
1432 return -EPERM;
1433 err = netlink_realloc_groups(sk);
1434 if (err)
1435 return err;
1436 }
1437
1438 if (nlk->portid) {
1439 if (nladdr->nl_pid != nlk->portid)
1440 return -EINVAL;
1441 } else {
1442 err = nladdr->nl_pid ?
1443 netlink_insert(sk, net, nladdr->nl_pid) :
1444 netlink_autobind(sock);
1445 if (err)
1446 return err;
1447 }
1448
1449 if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
1450 return 0;
1451
1452 netlink_table_grab();
1453 netlink_update_subscriptions(sk, nlk->subscriptions +
1454 hweight32(nladdr->nl_groups) -
1455 hweight32(nlk->groups[0]));
1456 nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
1457 netlink_update_listeners(sk);
1458 netlink_table_ungrab();
1459
1460 if (nlk->netlink_bind && nlk->groups[0]) {
1461 int i;
1462
1463 for (i = 0; i < nlk->ngroups; i++) {
1464 if (test_bit(i, nlk->groups))
1465 nlk->netlink_bind(i);
1466 }
1467 }
1468
1469 return 0;
1470 }
1471
1472 static int netlink_connect(struct socket *sock, struct sockaddr *addr,
1473 int alen, int flags)
1474 {
1475 int err = 0;
1476 struct sock *sk = sock->sk;
1477 struct netlink_sock *nlk = nlk_sk(sk);
1478 struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
1479
1480 if (alen < sizeof(addr->sa_family))
1481 return -EINVAL;
1482
1483 if (addr->sa_family == AF_UNSPEC) {
1484 sk->sk_state = NETLINK_UNCONNECTED;
1485 nlk->dst_portid = 0;
1486 nlk->dst_group = 0;
1487 return 0;
1488 }
1489 if (addr->sa_family != AF_NETLINK)
1490 return -EINVAL;
1491
1492 if ((nladdr->nl_groups || nladdr->nl_pid) &&
1493 !netlink_capable(sock, NL_CFG_F_NONROOT_SEND))
1494 return -EPERM;
1495
1496 if (!nlk->portid)
1497 err = netlink_autobind(sock);
1498
1499 if (err == 0) {
1500 sk->sk_state = NETLINK_CONNECTED;
1501 nlk->dst_portid = nladdr->nl_pid;
1502 nlk->dst_group = ffs(nladdr->nl_groups);
1503 }
1504
1505 return err;
1506 }
1507
1508 static int netlink_getname(struct socket *sock, struct sockaddr *addr,
1509 int *addr_len, int peer)
1510 {
1511 struct sock *sk = sock->sk;
1512 struct netlink_sock *nlk = nlk_sk(sk);
1513 DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
1514
1515 nladdr->nl_family = AF_NETLINK;
1516 nladdr->nl_pad = 0;
1517 *addr_len = sizeof(*nladdr);
1518
1519 if (peer) {
1520 nladdr->nl_pid = nlk->dst_portid;
1521 nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
1522 } else {
1523 nladdr->nl_pid = nlk->portid;
1524 nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
1525 }
1526 return 0;
1527 }
1528
1529 static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
1530 {
1531 struct sock *sock;
1532 struct netlink_sock *nlk;
1533
1534 sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
1535 if (!sock)
1536 return ERR_PTR(-ECONNREFUSED);
1537
1538 /* Don't bother queuing skb if kernel socket has no input function */
1539 nlk = nlk_sk(sock);
1540 if (sock->sk_state == NETLINK_CONNECTED &&
1541 nlk->dst_portid != nlk_sk(ssk)->portid) {
1542 sock_put(sock);
1543 return ERR_PTR(-ECONNREFUSED);
1544 }
1545 return sock;
1546 }
1547
1548 struct sock *netlink_getsockbyfilp(struct file *filp)
1549 {
1550 struct inode *inode = file_inode(filp);
1551 struct sock *sock;
1552
1553 if (!S_ISSOCK(inode->i_mode))
1554 return ERR_PTR(-ENOTSOCK);
1555
1556 sock = SOCKET_I(inode)->sk;
1557 if (sock->sk_family != AF_NETLINK)
1558 return ERR_PTR(-EINVAL);
1559
1560 sock_hold(sock);
1561 return sock;
1562 }
1563
1564 static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
1565 int broadcast)
1566 {
1567 struct sk_buff *skb;
1568 void *data;
1569
1570 if (size <= NLMSG_GOODSIZE || broadcast)
1571 return alloc_skb(size, GFP_KERNEL);
1572
1573 size = SKB_DATA_ALIGN(size) +
1574 SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
1575
1576 data = vmalloc(size);
1577 if (data == NULL)
1578 return NULL;
1579
1580 skb = build_skb(data, size);
1581 if (skb == NULL)
1582 vfree(data);
1583 else {
1584 skb->head_frag = 0;
1585 skb->destructor = netlink_skb_destructor;
1586 }
1587
1588 return skb;
1589 }
1590
1591 /*
1592 * Attach a skb to a netlink socket.
1593 * The caller must hold a reference to the destination socket. On error, the
1594 * reference is dropped. The skb is not send to the destination, just all
1595 * all error checks are performed and memory in the queue is reserved.
1596 * Return values:
1597 * < 0: error. skb freed, reference to sock dropped.
1598 * 0: continue
1599 * 1: repeat lookup - reference dropped while waiting for socket memory.
1600 */
1601 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
1602 long *timeo, struct sock *ssk)
1603 {
1604 struct netlink_sock *nlk;
1605
1606 nlk = nlk_sk(sk);
1607
1608 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1609 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1610 !netlink_skb_is_mmaped(skb)) {
1611 DECLARE_WAITQUEUE(wait, current);
1612 if (!*timeo) {
1613 if (!ssk || netlink_is_kernel(ssk))
1614 netlink_overrun(sk);
1615 sock_put(sk);
1616 kfree_skb(skb);
1617 return -EAGAIN;
1618 }
1619
1620 __set_current_state(TASK_INTERRUPTIBLE);
1621 add_wait_queue(&nlk->wait, &wait);
1622
1623 if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
1624 test_bit(NETLINK_CONGESTED, &nlk->state)) &&
1625 !sock_flag(sk, SOCK_DEAD))
1626 *timeo = schedule_timeout(*timeo);
1627
1628 __set_current_state(TASK_RUNNING);
1629 remove_wait_queue(&nlk->wait, &wait);
1630 sock_put(sk);
1631
1632 if (signal_pending(current)) {
1633 kfree_skb(skb);
1634 return sock_intr_errno(*timeo);
1635 }
1636 return 1;
1637 }
1638 netlink_skb_set_owner_r(skb, sk);
1639 return 0;
1640 }
1641
1642 static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1643 {
1644 int len = skb->len;
1645
1646 netlink_deliver_tap(skb);
1647
1648 #ifdef CONFIG_NETLINK_MMAP
1649 if (netlink_skb_is_mmaped(skb))
1650 netlink_queue_mmaped_skb(sk, skb);
1651 else if (netlink_rx_is_mmaped(sk))
1652 netlink_ring_set_copied(sk, skb);
1653 else
1654 #endif /* CONFIG_NETLINK_MMAP */
1655 skb_queue_tail(&sk->sk_receive_queue, skb);
1656 sk->sk_data_ready(sk);
1657 return len;
1658 }
1659
1660 int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
1661 {
1662 int len = __netlink_sendskb(sk, skb);
1663
1664 sock_put(sk);
1665 return len;
1666 }
1667
1668 void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
1669 {
1670 kfree_skb(skb);
1671 sock_put(sk);
1672 }
1673
1674 static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
1675 {
1676 int delta;
1677
1678 WARN_ON(skb->sk != NULL);
1679 if (netlink_skb_is_mmaped(skb))
1680 return skb;
1681
1682 delta = skb->end - skb->tail;
1683 if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
1684 return skb;
1685
1686 if (skb_shared(skb)) {
1687 struct sk_buff *nskb = skb_clone(skb, allocation);
1688 if (!nskb)
1689 return skb;
1690 consume_skb(skb);
1691 skb = nskb;
1692 }
1693
1694 if (!pskb_expand_head(skb, 0, -delta, allocation))
1695 skb->truesize -= delta;
1696
1697 return skb;
1698 }
1699
1700 static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
1701 struct sock *ssk)
1702 {
1703 int ret;
1704 struct netlink_sock *nlk = nlk_sk(sk);
1705
1706 ret = -ECONNREFUSED;
1707 if (nlk->netlink_rcv != NULL) {
1708 ret = skb->len;
1709 netlink_skb_set_owner_r(skb, sk);
1710 NETLINK_CB(skb).sk = ssk;
1711 netlink_deliver_tap_kernel(sk, ssk, skb);
1712 nlk->netlink_rcv(skb);
1713 consume_skb(skb);
1714 } else {
1715 kfree_skb(skb);
1716 }
1717 sock_put(sk);
1718 return ret;
1719 }
1720
1721 int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
1722 u32 portid, int nonblock)
1723 {
1724 struct sock *sk;
1725 int err;
1726 long timeo;
1727
1728 skb = netlink_trim(skb, gfp_any());
1729
1730 timeo = sock_sndtimeo(ssk, nonblock);
1731 retry:
1732 sk = netlink_getsockbyportid(ssk, portid);
1733 if (IS_ERR(sk)) {
1734 kfree_skb(skb);
1735 return PTR_ERR(sk);
1736 }
1737 if (netlink_is_kernel(sk))
1738 return netlink_unicast_kernel(sk, skb, ssk);
1739
1740 if (sk_filter(sk, skb)) {
1741 err = skb->len;
1742 kfree_skb(skb);
1743 sock_put(sk);
1744 return err;
1745 }
1746
1747 err = netlink_attachskb(sk, skb, &timeo, ssk);
1748 if (err == 1)
1749 goto retry;
1750 if (err)
1751 return err;
1752
1753 return netlink_sendskb(sk, skb);
1754 }
1755 EXPORT_SYMBOL(netlink_unicast);
1756
1757 struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
1758 u32 dst_portid, gfp_t gfp_mask)
1759 {
1760 #ifdef CONFIG_NETLINK_MMAP
1761 struct sock *sk = NULL;
1762 struct sk_buff *skb;
1763 struct netlink_ring *ring;
1764 struct nl_mmap_hdr *hdr;
1765 unsigned int maxlen;
1766
1767 sk = netlink_getsockbyportid(ssk, dst_portid);
1768 if (IS_ERR(sk))
1769 goto out;
1770
1771 ring = &nlk_sk(sk)->rx_ring;
1772 /* fast-path without atomic ops for common case: non-mmaped receiver */
1773 if (ring->pg_vec == NULL)
1774 goto out_put;
1775
1776 if (ring->frame_size - NL_MMAP_HDRLEN < size)
1777 goto out_put;
1778
1779 skb = alloc_skb_head(gfp_mask);
1780 if (skb == NULL)
1781 goto err1;
1782
1783 spin_lock_bh(&sk->sk_receive_queue.lock);
1784 /* check again under lock */
1785 if (ring->pg_vec == NULL)
1786 goto out_free;
1787
1788 /* check again under lock */
1789 maxlen = ring->frame_size - NL_MMAP_HDRLEN;
1790 if (maxlen < size)
1791 goto out_free;
1792
1793 netlink_forward_ring(ring);
1794 hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
1795 if (hdr == NULL)
1796 goto err2;
1797 netlink_ring_setup_skb(skb, sk, ring, hdr);
1798 netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
1799 atomic_inc(&ring->pending);
1800 netlink_increment_head(ring);
1801
1802 spin_unlock_bh(&sk->sk_receive_queue.lock);
1803 return skb;
1804
1805 err2:
1806 kfree_skb(skb);
1807 spin_unlock_bh(&sk->sk_receive_queue.lock);
1808 netlink_overrun(sk);
1809 err1:
1810 sock_put(sk);
1811 return NULL;
1812
1813 out_free:
1814 kfree_skb(skb);
1815 spin_unlock_bh(&sk->sk_receive_queue.lock);
1816 out_put:
1817 sock_put(sk);
1818 out:
1819 #endif
1820 return alloc_skb(size, gfp_mask);
1821 }
1822 EXPORT_SYMBOL_GPL(netlink_alloc_skb);
1823
1824 int netlink_has_listeners(struct sock *sk, unsigned int group)
1825 {
1826 int res = 0;
1827 struct listeners *listeners;
1828
1829 BUG_ON(!netlink_is_kernel(sk));
1830
1831 rcu_read_lock();
1832 listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
1833
1834 if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
1835 res = test_bit(group - 1, listeners->masks);
1836
1837 rcu_read_unlock();
1838
1839 return res;
1840 }
1841 EXPORT_SYMBOL_GPL(netlink_has_listeners);
1842
1843 static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
1844 {
1845 struct netlink_sock *nlk = nlk_sk(sk);
1846
1847 if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
1848 !test_bit(NETLINK_CONGESTED, &nlk->state)) {
1849 netlink_skb_set_owner_r(skb, sk);
1850 __netlink_sendskb(sk, skb);
1851 return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
1852 }
1853 return -1;
1854 }
1855
1856 struct netlink_broadcast_data {
1857 struct sock *exclude_sk;
1858 struct net *net;
1859 u32 portid;
1860 u32 group;
1861 int failure;
1862 int delivery_failure;
1863 int congested;
1864 int delivered;
1865 gfp_t allocation;
1866 struct sk_buff *skb, *skb2;
1867 int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
1868 void *tx_data;
1869 };
1870
1871 static int do_one_broadcast(struct sock *sk,
1872 struct netlink_broadcast_data *p)
1873 {
1874 struct netlink_sock *nlk = nlk_sk(sk);
1875 int val;
1876
1877 if (p->exclude_sk == sk)
1878 goto out;
1879
1880 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
1881 !test_bit(p->group - 1, nlk->groups))
1882 goto out;
1883
1884 if (!net_eq(sock_net(sk), p->net))
1885 goto out;
1886
1887 if (p->failure) {
1888 netlink_overrun(sk);
1889 goto out;
1890 }
1891
1892 sock_hold(sk);
1893 if (p->skb2 == NULL) {
1894 if (skb_shared(p->skb)) {
1895 p->skb2 = skb_clone(p->skb, p->allocation);
1896 } else {
1897 p->skb2 = skb_get(p->skb);
1898 /*
1899 * skb ownership may have been set when
1900 * delivered to a previous socket.
1901 */
1902 skb_orphan(p->skb2);
1903 }
1904 }
1905 if (p->skb2 == NULL) {
1906 netlink_overrun(sk);
1907 /* Clone failed. Notify ALL listeners. */
1908 p->failure = 1;
1909 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1910 p->delivery_failure = 1;
1911 } else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
1912 kfree_skb(p->skb2);
1913 p->skb2 = NULL;
1914 } else if (sk_filter(sk, p->skb2)) {
1915 kfree_skb(p->skb2);
1916 p->skb2 = NULL;
1917 } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
1918 netlink_overrun(sk);
1919 if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
1920 p->delivery_failure = 1;
1921 } else {
1922 p->congested |= val;
1923 p->delivered = 1;
1924 p->skb2 = NULL;
1925 }
1926 sock_put(sk);
1927
1928 out:
1929 return 0;
1930 }
1931
1932 int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
1933 u32 group, gfp_t allocation,
1934 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
1935 void *filter_data)
1936 {
1937 struct net *net = sock_net(ssk);
1938 struct netlink_broadcast_data info;
1939 struct sock *sk;
1940
1941 skb = netlink_trim(skb, allocation);
1942
1943 info.exclude_sk = ssk;
1944 info.net = net;
1945 info.portid = portid;
1946 info.group = group;
1947 info.failure = 0;
1948 info.delivery_failure = 0;
1949 info.congested = 0;
1950 info.delivered = 0;
1951 info.allocation = allocation;
1952 info.skb = skb;
1953 info.skb2 = NULL;
1954 info.tx_filter = filter;
1955 info.tx_data = filter_data;
1956
1957 /* While we sleep in clone, do not allow to change socket list */
1958
1959 netlink_lock_table();
1960
1961 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
1962 do_one_broadcast(sk, &info);
1963
1964 consume_skb(skb);
1965
1966 netlink_unlock_table();
1967
1968 if (info.delivery_failure) {
1969 kfree_skb(info.skb2);
1970 return -ENOBUFS;
1971 }
1972 consume_skb(info.skb2);
1973
1974 if (info.delivered) {
1975 if (info.congested && (allocation & __GFP_WAIT))
1976 yield();
1977 return 0;
1978 }
1979 return -ESRCH;
1980 }
1981 EXPORT_SYMBOL(netlink_broadcast_filtered);
1982
1983 int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
1984 u32 group, gfp_t allocation)
1985 {
1986 return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
1987 NULL, NULL);
1988 }
1989 EXPORT_SYMBOL(netlink_broadcast);
1990
1991 struct netlink_set_err_data {
1992 struct sock *exclude_sk;
1993 u32 portid;
1994 u32 group;
1995 int code;
1996 };
1997
1998 static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
1999 {
2000 struct netlink_sock *nlk = nlk_sk(sk);
2001 int ret = 0;
2002
2003 if (sk == p->exclude_sk)
2004 goto out;
2005
2006 if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
2007 goto out;
2008
2009 if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
2010 !test_bit(p->group - 1, nlk->groups))
2011 goto out;
2012
2013 if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
2014 ret = 1;
2015 goto out;
2016 }
2017
2018 sk->sk_err = p->code;
2019 sk->sk_error_report(sk);
2020 out:
2021 return ret;
2022 }
2023
2024 /**
2025 * netlink_set_err - report error to broadcast listeners
2026 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
2027 * @portid: the PORTID of a process that we want to skip (if any)
2028 * @group: the broadcast group that will notice the error
2029 * @code: error code, must be negative (as usual in kernelspace)
2030 *
2031 * This function returns the number of broadcast listeners that have set the
2032 * NETLINK_RECV_NO_ENOBUFS socket option.
2033 */
2034 int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
2035 {
2036 struct netlink_set_err_data info;
2037 struct sock *sk;
2038 int ret = 0;
2039
2040 info.exclude_sk = ssk;
2041 info.portid = portid;
2042 info.group = group;
2043 /* sk->sk_err wants a positive error value */
2044 info.code = -code;
2045
2046 read_lock(&nl_table_lock);
2047
2048 sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
2049 ret += do_one_set_err(sk, &info);
2050
2051 read_unlock(&nl_table_lock);
2052 return ret;
2053 }
2054 EXPORT_SYMBOL(netlink_set_err);
2055
2056 /* must be called with netlink table grabbed */
2057 static void netlink_update_socket_mc(struct netlink_sock *nlk,
2058 unsigned int group,
2059 int is_new)
2060 {
2061 int old, new = !!is_new, subscriptions;
2062
2063 old = test_bit(group - 1, nlk->groups);
2064 subscriptions = nlk->subscriptions - old + new;
2065 if (new)
2066 __set_bit(group - 1, nlk->groups);
2067 else
2068 __clear_bit(group - 1, nlk->groups);
2069 netlink_update_subscriptions(&nlk->sk, subscriptions);
2070 netlink_update_listeners(&nlk->sk);
2071 }
2072
2073 static int netlink_setsockopt(struct socket *sock, int level, int optname,
2074 char __user *optval, unsigned int optlen)
2075 {
2076 struct sock *sk = sock->sk;
2077 struct netlink_sock *nlk = nlk_sk(sk);
2078 unsigned int val = 0;
2079 int err;
2080
2081 if (level != SOL_NETLINK)
2082 return -ENOPROTOOPT;
2083
2084 if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING &&
2085 optlen >= sizeof(int) &&
2086 get_user(val, (unsigned int __user *)optval))
2087 return -EFAULT;
2088
2089 switch (optname) {
2090 case NETLINK_PKTINFO:
2091 if (val)
2092 nlk->flags |= NETLINK_RECV_PKTINFO;
2093 else
2094 nlk->flags &= ~NETLINK_RECV_PKTINFO;
2095 err = 0;
2096 break;
2097 case NETLINK_ADD_MEMBERSHIP:
2098 case NETLINK_DROP_MEMBERSHIP: {
2099 if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV))
2100 return -EPERM;
2101 err = netlink_realloc_groups(sk);
2102 if (err)
2103 return err;
2104 if (!val || val - 1 >= nlk->ngroups)
2105 return -EINVAL;
2106 netlink_table_grab();
2107 netlink_update_socket_mc(nlk, val,
2108 optname == NETLINK_ADD_MEMBERSHIP);
2109 netlink_table_ungrab();
2110
2111 if (nlk->netlink_bind)
2112 nlk->netlink_bind(val);
2113
2114 err = 0;
2115 break;
2116 }
2117 case NETLINK_BROADCAST_ERROR:
2118 if (val)
2119 nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
2120 else
2121 nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
2122 err = 0;
2123 break;
2124 case NETLINK_NO_ENOBUFS:
2125 if (val) {
2126 nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
2127 clear_bit(NETLINK_CONGESTED, &nlk->state);
2128 wake_up_interruptible(&nlk->wait);
2129 } else {
2130 nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
2131 }
2132 err = 0;
2133 break;
2134 #ifdef CONFIG_NETLINK_MMAP
2135 case NETLINK_RX_RING:
2136 case NETLINK_TX_RING: {
2137 struct nl_mmap_req req;
2138
2139 /* Rings might consume more memory than queue limits, require
2140 * CAP_NET_ADMIN.
2141 */
2142 if (!capable(CAP_NET_ADMIN))
2143 return -EPERM;
2144 if (optlen < sizeof(req))
2145 return -EINVAL;
2146 if (copy_from_user(&req, optval, sizeof(req)))
2147 return -EFAULT;
2148 err = netlink_set_ring(sk, &req, false,
2149 optname == NETLINK_TX_RING);
2150 break;
2151 }
2152 #endif /* CONFIG_NETLINK_MMAP */
2153 default:
2154 err = -ENOPROTOOPT;
2155 }
2156 return err;
2157 }
2158
2159 static int netlink_getsockopt(struct socket *sock, int level, int optname,
2160 char __user *optval, int __user *optlen)
2161 {
2162 struct sock *sk = sock->sk;
2163 struct netlink_sock *nlk = nlk_sk(sk);
2164 int len, val, err;
2165
2166 if (level != SOL_NETLINK)
2167 return -ENOPROTOOPT;
2168
2169 if (get_user(len, optlen))
2170 return -EFAULT;
2171 if (len < 0)
2172 return -EINVAL;
2173
2174 switch (optname) {
2175 case NETLINK_PKTINFO:
2176 if (len < sizeof(int))
2177 return -EINVAL;
2178 len = sizeof(int);
2179 val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
2180 if (put_user(len, optlen) ||
2181 put_user(val, optval))
2182 return -EFAULT;
2183 err = 0;
2184 break;
2185 case NETLINK_BROADCAST_ERROR:
2186 if (len < sizeof(int))
2187 return -EINVAL;
2188 len = sizeof(int);
2189 val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
2190 if (put_user(len, optlen) ||
2191 put_user(val, optval))
2192 return -EFAULT;
2193 err = 0;
2194 break;
2195 case NETLINK_NO_ENOBUFS:
2196 if (len < sizeof(int))
2197 return -EINVAL;
2198 len = sizeof(int);
2199 val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
2200 if (put_user(len, optlen) ||
2201 put_user(val, optval))
2202 return -EFAULT;
2203 err = 0;
2204 break;
2205 default:
2206 err = -ENOPROTOOPT;
2207 }
2208 return err;
2209 }
2210
2211 static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
2212 {
2213 struct nl_pktinfo info;
2214
2215 info.group = NETLINK_CB(skb).dst_group;
2216 put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
2217 }
2218
2219 static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
2220 struct msghdr *msg, size_t len)
2221 {
2222 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2223 struct sock *sk = sock->sk;
2224 struct netlink_sock *nlk = nlk_sk(sk);
2225 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2226 u32 dst_portid;
2227 u32 dst_group;
2228 struct sk_buff *skb;
2229 int err;
2230 struct scm_cookie scm;
2231
2232 if (msg->msg_flags&MSG_OOB)
2233 return -EOPNOTSUPP;
2234
2235 if (NULL == siocb->scm)
2236 siocb->scm = &scm;
2237
2238 err = scm_send(sock, msg, siocb->scm, true);
2239 if (err < 0)
2240 return err;
2241
2242 if (msg->msg_namelen) {
2243 err = -EINVAL;
2244 if (addr->nl_family != AF_NETLINK)
2245 goto out;
2246 dst_portid = addr->nl_pid;
2247 dst_group = ffs(addr->nl_groups);
2248 err = -EPERM;
2249 if ((dst_group || dst_portid) &&
2250 !netlink_capable(sock, NL_CFG_F_NONROOT_SEND))
2251 goto out;
2252 } else {
2253 dst_portid = nlk->dst_portid;
2254 dst_group = nlk->dst_group;
2255 }
2256
2257 if (!nlk->portid) {
2258 err = netlink_autobind(sock);
2259 if (err)
2260 goto out;
2261 }
2262
2263 if (netlink_tx_is_mmaped(sk) &&
2264 msg->msg_iov->iov_base == NULL) {
2265 err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
2266 siocb);
2267 goto out;
2268 }
2269
2270 err = -EMSGSIZE;
2271 if (len > sk->sk_sndbuf - 32)
2272 goto out;
2273 err = -ENOBUFS;
2274 skb = netlink_alloc_large_skb(len, dst_group);
2275 if (skb == NULL)
2276 goto out;
2277
2278 NETLINK_CB(skb).portid = nlk->portid;
2279 NETLINK_CB(skb).dst_group = dst_group;
2280 NETLINK_CB(skb).creds = siocb->scm->creds;
2281
2282 err = -EFAULT;
2283 if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
2284 kfree_skb(skb);
2285 goto out;
2286 }
2287
2288 err = security_netlink_send(sk, skb);
2289 if (err) {
2290 kfree_skb(skb);
2291 goto out;
2292 }
2293
2294 if (dst_group) {
2295 atomic_inc(&skb->users);
2296 netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
2297 }
2298 err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
2299
2300 out:
2301 scm_destroy(siocb->scm);
2302 return err;
2303 }
2304
2305 static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
2306 struct msghdr *msg, size_t len,
2307 int flags)
2308 {
2309 struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
2310 struct scm_cookie scm;
2311 struct sock *sk = sock->sk;
2312 struct netlink_sock *nlk = nlk_sk(sk);
2313 int noblock = flags&MSG_DONTWAIT;
2314 size_t copied;
2315 struct sk_buff *skb, *data_skb;
2316 int err, ret;
2317
2318 if (flags&MSG_OOB)
2319 return -EOPNOTSUPP;
2320
2321 copied = 0;
2322
2323 skb = skb_recv_datagram(sk, flags, noblock, &err);
2324 if (skb == NULL)
2325 goto out;
2326
2327 data_skb = skb;
2328
2329 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2330 if (unlikely(skb_shinfo(skb)->frag_list)) {
2331 /*
2332 * If this skb has a frag_list, then here that means that we
2333 * will have to use the frag_list skb's data for compat tasks
2334 * and the regular skb's data for normal (non-compat) tasks.
2335 *
2336 * If we need to send the compat skb, assign it to the
2337 * 'data_skb' variable so that it will be used below for data
2338 * copying. We keep 'skb' for everything else, including
2339 * freeing both later.
2340 */
2341 if (flags & MSG_CMSG_COMPAT)
2342 data_skb = skb_shinfo(skb)->frag_list;
2343 }
2344 #endif
2345
2346 /* Record the max length of recvmsg() calls for future allocations */
2347 nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
2348 nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
2349 16384);
2350
2351 copied = data_skb->len;
2352 if (len < copied) {
2353 msg->msg_flags |= MSG_TRUNC;
2354 copied = len;
2355 }
2356
2357 skb_reset_transport_header(data_skb);
2358 err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
2359
2360 if (msg->msg_name) {
2361 DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
2362 addr->nl_family = AF_NETLINK;
2363 addr->nl_pad = 0;
2364 addr->nl_pid = NETLINK_CB(skb).portid;
2365 addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
2366 msg->msg_namelen = sizeof(*addr);
2367 }
2368
2369 if (nlk->flags & NETLINK_RECV_PKTINFO)
2370 netlink_cmsg_recv_pktinfo(msg, skb);
2371
2372 if (NULL == siocb->scm) {
2373 memset(&scm, 0, sizeof(scm));
2374 siocb->scm = &scm;
2375 }
2376 siocb->scm->creds = *NETLINK_CREDS(skb);
2377 if (flags & MSG_TRUNC)
2378 copied = data_skb->len;
2379
2380 skb_free_datagram(sk, skb);
2381
2382 if (nlk->cb_running &&
2383 atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
2384 ret = netlink_dump(sk);
2385 if (ret) {
2386 sk->sk_err = ret;
2387 sk->sk_error_report(sk);
2388 }
2389 }
2390
2391 scm_recv(sock, msg, siocb->scm, flags);
2392 out:
2393 netlink_rcv_wake(sk);
2394 return err ? : copied;
2395 }
2396
2397 static void netlink_data_ready(struct sock *sk)
2398 {
2399 BUG();
2400 }
2401
2402 /*
2403 * We export these functions to other modules. They provide a
2404 * complete set of kernel non-blocking support for message
2405 * queueing.
2406 */
2407
2408 struct sock *
2409 __netlink_kernel_create(struct net *net, int unit, struct module *module,
2410 struct netlink_kernel_cfg *cfg)
2411 {
2412 struct socket *sock;
2413 struct sock *sk;
2414 struct netlink_sock *nlk;
2415 struct listeners *listeners = NULL;
2416 struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
2417 unsigned int groups;
2418
2419 BUG_ON(!nl_table);
2420
2421 if (unit < 0 || unit >= MAX_LINKS)
2422 return NULL;
2423
2424 if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
2425 return NULL;
2426
2427 /*
2428 * We have to just have a reference on the net from sk, but don't
2429 * get_net it. Besides, we cannot get and then put the net here.
2430 * So we create one inside init_net and the move it to net.
2431 */
2432
2433 if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
2434 goto out_sock_release_nosk;
2435
2436 sk = sock->sk;
2437 sk_change_net(sk, net);
2438
2439 if (!cfg || cfg->groups < 32)
2440 groups = 32;
2441 else
2442 groups = cfg->groups;
2443
2444 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
2445 if (!listeners)
2446 goto out_sock_release;
2447
2448 sk->sk_data_ready = netlink_data_ready;
2449 if (cfg && cfg->input)
2450 nlk_sk(sk)->netlink_rcv = cfg->input;
2451
2452 if (netlink_insert(sk, net, 0))
2453 goto out_sock_release;
2454
2455 nlk = nlk_sk(sk);
2456 nlk->flags |= NETLINK_KERNEL_SOCKET;
2457
2458 netlink_table_grab();
2459 if (!nl_table[unit].registered) {
2460 nl_table[unit].groups = groups;
2461 rcu_assign_pointer(nl_table[unit].listeners, listeners);
2462 nl_table[unit].cb_mutex = cb_mutex;
2463 nl_table[unit].module = module;
2464 if (cfg) {
2465 nl_table[unit].bind = cfg->bind;
2466 nl_table[unit].flags = cfg->flags;
2467 if (cfg->compare)
2468 nl_table[unit].compare = cfg->compare;
2469 }
2470 nl_table[unit].registered = 1;
2471 } else {
2472 kfree(listeners);
2473 nl_table[unit].registered++;
2474 }
2475 netlink_table_ungrab();
2476 return sk;
2477
2478 out_sock_release:
2479 kfree(listeners);
2480 netlink_kernel_release(sk);
2481 return NULL;
2482
2483 out_sock_release_nosk:
2484 sock_release(sock);
2485 return NULL;
2486 }
2487 EXPORT_SYMBOL(__netlink_kernel_create);
2488
2489 void
2490 netlink_kernel_release(struct sock *sk)
2491 {
2492 sk_release_kernel(sk);
2493 }
2494 EXPORT_SYMBOL(netlink_kernel_release);
2495
2496 int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
2497 {
2498 struct listeners *new, *old;
2499 struct netlink_table *tbl = &nl_table[sk->sk_protocol];
2500
2501 if (groups < 32)
2502 groups = 32;
2503
2504 if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
2505 new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
2506 if (!new)
2507 return -ENOMEM;
2508 old = nl_deref_protected(tbl->listeners);
2509 memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
2510 rcu_assign_pointer(tbl->listeners, new);
2511
2512 kfree_rcu(old, rcu);
2513 }
2514 tbl->groups = groups;
2515
2516 return 0;
2517 }
2518
2519 /**
2520 * netlink_change_ngroups - change number of multicast groups
2521 *
2522 * This changes the number of multicast groups that are available
2523 * on a certain netlink family. Note that it is not possible to
2524 * change the number of groups to below 32. Also note that it does
2525 * not implicitly call netlink_clear_multicast_users() when the
2526 * number of groups is reduced.
2527 *
2528 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2529 * @groups: The new number of groups.
2530 */
2531 int netlink_change_ngroups(struct sock *sk, unsigned int groups)
2532 {
2533 int err;
2534
2535 netlink_table_grab();
2536 err = __netlink_change_ngroups(sk, groups);
2537 netlink_table_ungrab();
2538
2539 return err;
2540 }
2541
2542 void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
2543 {
2544 struct sock *sk;
2545 struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
2546
2547 sk_for_each_bound(sk, &tbl->mc_list)
2548 netlink_update_socket_mc(nlk_sk(sk), group, 0);
2549 }
2550
2551 struct nlmsghdr *
2552 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
2553 {
2554 struct nlmsghdr *nlh;
2555 int size = nlmsg_msg_size(len);
2556
2557 nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_ALIGN(size));
2558 nlh->nlmsg_type = type;
2559 nlh->nlmsg_len = size;
2560 nlh->nlmsg_flags = flags;
2561 nlh->nlmsg_pid = portid;
2562 nlh->nlmsg_seq = seq;
2563 if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
2564 memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
2565 return nlh;
2566 }
2567 EXPORT_SYMBOL(__nlmsg_put);
2568
2569 /*
2570 * It looks a bit ugly.
2571 * It would be better to create kernel thread.
2572 */
2573
2574 static int netlink_dump(struct sock *sk)
2575 {
2576 struct netlink_sock *nlk = nlk_sk(sk);
2577 struct netlink_callback *cb;
2578 struct sk_buff *skb = NULL;
2579 struct nlmsghdr *nlh;
2580 int len, err = -ENOBUFS;
2581 int alloc_size;
2582
2583 mutex_lock(nlk->cb_mutex);
2584 if (!nlk->cb_running) {
2585 err = -EINVAL;
2586 goto errout_skb;
2587 }
2588
2589 cb = &nlk->cb;
2590 alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
2591
2592 if (!netlink_rx_is_mmaped(sk) &&
2593 atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
2594 goto errout_skb;
2595
2596 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2597 * required, but it makes sense to _attempt_ a 16K bytes allocation
2598 * to reduce number of system calls on dump operations, if user
2599 * ever provided a big enough buffer.
2600 */
2601 if (alloc_size < nlk->max_recvmsg_len) {
2602 skb = netlink_alloc_skb(sk,
2603 nlk->max_recvmsg_len,
2604 nlk->portid,
2605 GFP_KERNEL |
2606 __GFP_NOWARN |
2607 __GFP_NORETRY);
2608 /* available room should be exact amount to avoid MSG_TRUNC */
2609 if (skb)
2610 skb_reserve(skb, skb_tailroom(skb) -
2611 nlk->max_recvmsg_len);
2612 }
2613 if (!skb)
2614 skb = netlink_alloc_skb(sk, alloc_size, nlk->portid,
2615 GFP_KERNEL);
2616 if (!skb)
2617 goto errout_skb;
2618 netlink_skb_set_owner_r(skb, sk);
2619
2620 len = cb->dump(skb, cb);
2621
2622 if (len > 0) {
2623 mutex_unlock(nlk->cb_mutex);
2624
2625 if (sk_filter(sk, skb))
2626 kfree_skb(skb);
2627 else
2628 __netlink_sendskb(sk, skb);
2629 return 0;
2630 }
2631
2632 nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
2633 if (!nlh)
2634 goto errout_skb;
2635
2636 nl_dump_check_consistent(cb, nlh);
2637
2638 memcpy(nlmsg_data(nlh), &len, sizeof(len));
2639
2640 if (sk_filter(sk, skb))
2641 kfree_skb(skb);
2642 else
2643 __netlink_sendskb(sk, skb);
2644
2645 if (cb->done)
2646 cb->done(cb);
2647
2648 nlk->cb_running = false;
2649 mutex_unlock(nlk->cb_mutex);
2650 module_put(cb->module);
2651 consume_skb(cb->skb);
2652 return 0;
2653
2654 errout_skb:
2655 mutex_unlock(nlk->cb_mutex);
2656 kfree_skb(skb);
2657 return err;
2658 }
2659
2660 int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
2661 const struct nlmsghdr *nlh,
2662 struct netlink_dump_control *control)
2663 {
2664 struct netlink_callback *cb;
2665 struct sock *sk;
2666 struct netlink_sock *nlk;
2667 int ret;
2668
2669 /* Memory mapped dump requests need to be copied to avoid looping
2670 * on the pending state in netlink_mmap_sendmsg() while the CB hold
2671 * a reference to the skb.
2672 */
2673 if (netlink_skb_is_mmaped(skb)) {
2674 skb = skb_copy(skb, GFP_KERNEL);
2675 if (skb == NULL)
2676 return -ENOBUFS;
2677 } else
2678 atomic_inc(&skb->users);
2679
2680 sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
2681 if (sk == NULL) {
2682 ret = -ECONNREFUSED;
2683 goto error_free;
2684 }
2685
2686 nlk = nlk_sk(sk);
2687 mutex_lock(nlk->cb_mutex);
2688 /* A dump is in progress... */
2689 if (nlk->cb_running) {
2690 ret = -EBUSY;
2691 goto error_unlock;
2692 }
2693 /* add reference of module which cb->dump belongs to */
2694 if (!try_module_get(control->module)) {
2695 ret = -EPROTONOSUPPORT;
2696 goto error_unlock;
2697 }
2698
2699 cb = &nlk->cb;
2700 memset(cb, 0, sizeof(*cb));
2701 cb->dump = control->dump;
2702 cb->done = control->done;
2703 cb->nlh = nlh;
2704 cb->data = control->data;
2705 cb->module = control->module;
2706 cb->min_dump_alloc = control->min_dump_alloc;
2707 cb->skb = skb;
2708
2709 nlk->cb_running = true;
2710
2711 mutex_unlock(nlk->cb_mutex);
2712
2713 ret = netlink_dump(sk);
2714 sock_put(sk);
2715
2716 if (ret)
2717 return ret;
2718
2719 /* We successfully started a dump, by returning -EINTR we
2720 * signal not to send ACK even if it was requested.
2721 */
2722 return -EINTR;
2723
2724 error_unlock:
2725 sock_put(sk);
2726 mutex_unlock(nlk->cb_mutex);
2727 error_free:
2728 kfree_skb(skb);
2729 return ret;
2730 }
2731 EXPORT_SYMBOL(__netlink_dump_start);
2732
2733 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
2734 {
2735 struct sk_buff *skb;
2736 struct nlmsghdr *rep;
2737 struct nlmsgerr *errmsg;
2738 size_t payload = sizeof(*errmsg);
2739
2740 /* error messages get the original request appened */
2741 if (err)
2742 payload += nlmsg_len(nlh);
2743
2744 skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload),
2745 NETLINK_CB(in_skb).portid, GFP_KERNEL);
2746 if (!skb) {
2747 struct sock *sk;
2748
2749 sk = netlink_lookup(sock_net(in_skb->sk),
2750 in_skb->sk->sk_protocol,
2751 NETLINK_CB(in_skb).portid);
2752 if (sk) {
2753 sk->sk_err = ENOBUFS;
2754 sk->sk_error_report(sk);
2755 sock_put(sk);
2756 }
2757 return;
2758 }
2759
2760 rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
2761 NLMSG_ERROR, payload, 0);
2762 errmsg = nlmsg_data(rep);
2763 errmsg->error = err;
2764 memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
2765 netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
2766 }
2767 EXPORT_SYMBOL(netlink_ack);
2768
2769 int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
2770 struct nlmsghdr *))
2771 {
2772 struct nlmsghdr *nlh;
2773 int err;
2774
2775 while (skb->len >= nlmsg_total_size(0)) {
2776 int msglen;
2777
2778 nlh = nlmsg_hdr(skb);
2779 err = 0;
2780
2781 if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
2782 return 0;
2783
2784 /* Only requests are handled by the kernel */
2785 if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
2786 goto ack;
2787
2788 /* Skip control messages */
2789 if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
2790 goto ack;
2791
2792 err = cb(skb, nlh);
2793 if (err == -EINTR)
2794 goto skip;
2795
2796 ack:
2797 if (nlh->nlmsg_flags & NLM_F_ACK || err)
2798 netlink_ack(skb, nlh, err);
2799
2800 skip:
2801 msglen = NLMSG_ALIGN(nlh->nlmsg_len);
2802 if (msglen > skb->len)
2803 msglen = skb->len;
2804 skb_pull(skb, msglen);
2805 }
2806
2807 return 0;
2808 }
2809 EXPORT_SYMBOL(netlink_rcv_skb);
2810
2811 /**
2812 * nlmsg_notify - send a notification netlink message
2813 * @sk: netlink socket to use
2814 * @skb: notification message
2815 * @portid: destination netlink portid for reports or 0
2816 * @group: destination multicast group or 0
2817 * @report: 1 to report back, 0 to disable
2818 * @flags: allocation flags
2819 */
2820 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
2821 unsigned int group, int report, gfp_t flags)
2822 {
2823 int err = 0;
2824
2825 if (group) {
2826 int exclude_portid = 0;
2827
2828 if (report) {
2829 atomic_inc(&skb->users);
2830 exclude_portid = portid;
2831 }
2832
2833 /* errors reported via destination sk->sk_err, but propagate
2834 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2835 err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
2836 }
2837
2838 if (report) {
2839 int err2;
2840
2841 err2 = nlmsg_unicast(sk, skb, portid);
2842 if (!err || err == -ESRCH)
2843 err = err2;
2844 }
2845
2846 return err;
2847 }
2848 EXPORT_SYMBOL(nlmsg_notify);
2849
2850 #ifdef CONFIG_PROC_FS
2851 struct nl_seq_iter {
2852 struct seq_net_private p;
2853 int link;
2854 int hash_idx;
2855 };
2856
2857 static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
2858 {
2859 struct nl_seq_iter *iter = seq->private;
2860 int i, j;
2861 struct sock *s;
2862 loff_t off = 0;
2863
2864 for (i = 0; i < MAX_LINKS; i++) {
2865 struct nl_portid_hash *hash = &nl_table[i].hash;
2866
2867 for (j = 0; j <= hash->mask; j++) {
2868 sk_for_each(s, &hash->table[j]) {
2869 if (sock_net(s) != seq_file_net(seq))
2870 continue;
2871 if (off == pos) {
2872 iter->link = i;
2873 iter->hash_idx = j;
2874 return s;
2875 }
2876 ++off;
2877 }
2878 }
2879 }
2880 return NULL;
2881 }
2882
2883 static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
2884 __acquires(nl_table_lock)
2885 {
2886 read_lock(&nl_table_lock);
2887 return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
2888 }
2889
2890 static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2891 {
2892 struct sock *s;
2893 struct nl_seq_iter *iter;
2894 struct net *net;
2895 int i, j;
2896
2897 ++*pos;
2898
2899 if (v == SEQ_START_TOKEN)
2900 return netlink_seq_socket_idx(seq, 0);
2901
2902 net = seq_file_net(seq);
2903 iter = seq->private;
2904 s = v;
2905 do {
2906 s = sk_next(s);
2907 } while (s && !nl_table[s->sk_protocol].compare(net, s));
2908 if (s)
2909 return s;
2910
2911 i = iter->link;
2912 j = iter->hash_idx + 1;
2913
2914 do {
2915 struct nl_portid_hash *hash = &nl_table[i].hash;
2916
2917 for (; j <= hash->mask; j++) {
2918 s = sk_head(&hash->table[j]);
2919
2920 while (s && !nl_table[s->sk_protocol].compare(net, s))
2921 s = sk_next(s);
2922 if (s) {
2923 iter->link = i;
2924 iter->hash_idx = j;
2925 return s;
2926 }
2927 }
2928
2929 j = 0;
2930 } while (++i < MAX_LINKS);
2931
2932 return NULL;
2933 }
2934
2935 static void netlink_seq_stop(struct seq_file *seq, void *v)
2936 __releases(nl_table_lock)
2937 {
2938 read_unlock(&nl_table_lock);
2939 }
2940
2941
2942 static int netlink_seq_show(struct seq_file *seq, void *v)
2943 {
2944 if (v == SEQ_START_TOKEN) {
2945 seq_puts(seq,
2946 "sk Eth Pid Groups "
2947 "Rmem Wmem Dump Locks Drops Inode\n");
2948 } else {
2949 struct sock *s = v;
2950 struct netlink_sock *nlk = nlk_sk(s);
2951
2952 seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
2953 s,
2954 s->sk_protocol,
2955 nlk->portid,
2956 nlk->groups ? (u32)nlk->groups[0] : 0,
2957 sk_rmem_alloc_get(s),
2958 sk_wmem_alloc_get(s),
2959 nlk->cb_running,
2960 atomic_read(&s->sk_refcnt),
2961 atomic_read(&s->sk_drops),
2962 sock_i_ino(s)
2963 );
2964
2965 }
2966 return 0;
2967 }
2968
2969 static const struct seq_operations netlink_seq_ops = {
2970 .start = netlink_seq_start,
2971 .next = netlink_seq_next,
2972 .stop = netlink_seq_stop,
2973 .show = netlink_seq_show,
2974 };
2975
2976
2977 static int netlink_seq_open(struct inode *inode, struct file *file)
2978 {
2979 return seq_open_net(inode, file, &netlink_seq_ops,
2980 sizeof(struct nl_seq_iter));
2981 }
2982
2983 static const struct file_operations netlink_seq_fops = {
2984 .owner = THIS_MODULE,
2985 .open = netlink_seq_open,
2986 .read = seq_read,
2987 .llseek = seq_lseek,
2988 .release = seq_release_net,
2989 };
2990
2991 #endif
2992
2993 int netlink_register_notifier(struct notifier_block *nb)
2994 {
2995 return atomic_notifier_chain_register(&netlink_chain, nb);
2996 }
2997 EXPORT_SYMBOL(netlink_register_notifier);
2998
2999 int netlink_unregister_notifier(struct notifier_block *nb)
3000 {
3001 return atomic_notifier_chain_unregister(&netlink_chain, nb);
3002 }
3003 EXPORT_SYMBOL(netlink_unregister_notifier);
3004
3005 static const struct proto_ops netlink_ops = {
3006 .family = PF_NETLINK,
3007 .owner = THIS_MODULE,
3008 .release = netlink_release,
3009 .bind = netlink_bind,
3010 .connect = netlink_connect,
3011 .socketpair = sock_no_socketpair,
3012 .accept = sock_no_accept,
3013 .getname = netlink_getname,
3014 .poll = netlink_poll,
3015 .ioctl = sock_no_ioctl,
3016 .listen = sock_no_listen,
3017 .shutdown = sock_no_shutdown,
3018 .setsockopt = netlink_setsockopt,
3019 .getsockopt = netlink_getsockopt,
3020 .sendmsg = netlink_sendmsg,
3021 .recvmsg = netlink_recvmsg,
3022 .mmap = netlink_mmap,
3023 .sendpage = sock_no_sendpage,
3024 };
3025
3026 static const struct net_proto_family netlink_family_ops = {
3027 .family = PF_NETLINK,
3028 .create = netlink_create,
3029 .owner = THIS_MODULE, /* for consistency 8) */
3030 };
3031
3032 static int __net_init netlink_net_init(struct net *net)
3033 {
3034 #ifdef CONFIG_PROC_FS
3035 if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
3036 return -ENOMEM;
3037 #endif
3038 return 0;
3039 }
3040
3041 static void __net_exit netlink_net_exit(struct net *net)
3042 {
3043 #ifdef CONFIG_PROC_FS
3044 remove_proc_entry("netlink", net->proc_net);
3045 #endif
3046 }
3047
3048 static void __init netlink_add_usersock_entry(void)
3049 {
3050 struct listeners *listeners;
3051 int groups = 32;
3052
3053 listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
3054 if (!listeners)
3055 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
3056
3057 netlink_table_grab();
3058
3059 nl_table[NETLINK_USERSOCK].groups = groups;
3060 rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
3061 nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
3062 nl_table[NETLINK_USERSOCK].registered = 1;
3063 nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
3064
3065 netlink_table_ungrab();
3066 }
3067
3068 static struct pernet_operations __net_initdata netlink_net_ops = {
3069 .init = netlink_net_init,
3070 .exit = netlink_net_exit,
3071 };
3072
3073 static int __init netlink_proto_init(void)
3074 {
3075 int i;
3076 unsigned long limit;
3077 unsigned int order;
3078 int err = proto_register(&netlink_proto, 0);
3079
3080 if (err != 0)
3081 goto out;
3082
3083 BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
3084
3085 nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
3086 if (!nl_table)
3087 goto panic;
3088
3089 if (totalram_pages >= (128 * 1024))
3090 limit = totalram_pages >> (21 - PAGE_SHIFT);
3091 else
3092 limit = totalram_pages >> (23 - PAGE_SHIFT);
3093
3094 order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
3095 limit = (1UL << order) / sizeof(struct hlist_head);
3096 order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
3097
3098 for (i = 0; i < MAX_LINKS; i++) {
3099 struct nl_portid_hash *hash = &nl_table[i].hash;
3100
3101 hash->table = nl_portid_hash_zalloc(1 * sizeof(*hash->table));
3102 if (!hash->table) {
3103 while (i-- > 0)
3104 nl_portid_hash_free(nl_table[i].hash.table,
3105 1 * sizeof(*hash->table));
3106 kfree(nl_table);
3107 goto panic;
3108 }
3109 hash->max_shift = order;
3110 hash->shift = 0;
3111 hash->mask = 0;
3112 hash->rehash_time = jiffies;
3113
3114 nl_table[i].compare = netlink_compare;
3115 }
3116
3117 INIT_LIST_HEAD(&netlink_tap_all);
3118
3119 netlink_add_usersock_entry();
3120
3121 sock_register(&netlink_family_ops);
3122 register_pernet_subsys(&netlink_net_ops);
3123 /* The netlink device handler may be needed early. */
3124 rtnetlink_init();
3125 out:
3126 return err;
3127 panic:
3128 panic("netlink_init: Cannot allocate nl_table\n");
3129 }
3130
3131 core_initcall(netlink_proto_init);
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