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Merge branch 'keys-asym-keyctl' into keys-next
[deliverable/linux.git] / net / kcm / kcmsock.c
1 #include <linux/bpf.h>
2 #include <linux/errno.h>
3 #include <linux/errqueue.h>
4 #include <linux/file.h>
5 #include <linux/in.h>
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/net.h>
9 #include <linux/netdevice.h>
10 #include <linux/poll.h>
11 #include <linux/rculist.h>
12 #include <linux/skbuff.h>
13 #include <linux/socket.h>
14 #include <linux/uaccess.h>
15 #include <linux/workqueue.h>
16 #include <net/kcm.h>
17 #include <net/netns/generic.h>
18 #include <net/sock.h>
19 #include <net/tcp.h>
20 #include <uapi/linux/kcm.h>
21
22 unsigned int kcm_net_id;
23
24 static struct kmem_cache *kcm_psockp __read_mostly;
25 static struct kmem_cache *kcm_muxp __read_mostly;
26 static struct workqueue_struct *kcm_wq;
27
28 static inline struct kcm_sock *kcm_sk(const struct sock *sk)
29 {
30 return (struct kcm_sock *)sk;
31 }
32
33 static inline struct kcm_tx_msg *kcm_tx_msg(struct sk_buff *skb)
34 {
35 return (struct kcm_tx_msg *)skb->cb;
36 }
37
38 static inline struct kcm_rx_msg *kcm_rx_msg(struct sk_buff *skb)
39 {
40 return (struct kcm_rx_msg *)((void *)skb->cb +
41 offsetof(struct qdisc_skb_cb, data));
42 }
43
44 static void report_csk_error(struct sock *csk, int err)
45 {
46 csk->sk_err = EPIPE;
47 csk->sk_error_report(csk);
48 }
49
50 /* Callback lock held */
51 static void kcm_abort_rx_psock(struct kcm_psock *psock, int err,
52 struct sk_buff *skb)
53 {
54 struct sock *csk = psock->sk;
55
56 /* Unrecoverable error in receive */
57
58 del_timer(&psock->rx_msg_timer);
59
60 if (psock->rx_stopped)
61 return;
62
63 psock->rx_stopped = 1;
64 KCM_STATS_INCR(psock->stats.rx_aborts);
65
66 /* Report an error on the lower socket */
67 report_csk_error(csk, err);
68 }
69
70 static void kcm_abort_tx_psock(struct kcm_psock *psock, int err,
71 bool wakeup_kcm)
72 {
73 struct sock *csk = psock->sk;
74 struct kcm_mux *mux = psock->mux;
75
76 /* Unrecoverable error in transmit */
77
78 spin_lock_bh(&mux->lock);
79
80 if (psock->tx_stopped) {
81 spin_unlock_bh(&mux->lock);
82 return;
83 }
84
85 psock->tx_stopped = 1;
86 KCM_STATS_INCR(psock->stats.tx_aborts);
87
88 if (!psock->tx_kcm) {
89 /* Take off psocks_avail list */
90 list_del(&psock->psock_avail_list);
91 } else if (wakeup_kcm) {
92 /* In this case psock is being aborted while outside of
93 * write_msgs and psock is reserved. Schedule tx_work
94 * to handle the failure there. Need to commit tx_stopped
95 * before queuing work.
96 */
97 smp_mb();
98
99 queue_work(kcm_wq, &psock->tx_kcm->tx_work);
100 }
101
102 spin_unlock_bh(&mux->lock);
103
104 /* Report error on lower socket */
105 report_csk_error(csk, err);
106 }
107
108 /* RX mux lock held. */
109 static void kcm_update_rx_mux_stats(struct kcm_mux *mux,
110 struct kcm_psock *psock)
111 {
112 KCM_STATS_ADD(mux->stats.rx_bytes,
113 psock->stats.rx_bytes - psock->saved_rx_bytes);
114 mux->stats.rx_msgs +=
115 psock->stats.rx_msgs - psock->saved_rx_msgs;
116 psock->saved_rx_msgs = psock->stats.rx_msgs;
117 psock->saved_rx_bytes = psock->stats.rx_bytes;
118 }
119
120 static void kcm_update_tx_mux_stats(struct kcm_mux *mux,
121 struct kcm_psock *psock)
122 {
123 KCM_STATS_ADD(mux->stats.tx_bytes,
124 psock->stats.tx_bytes - psock->saved_tx_bytes);
125 mux->stats.tx_msgs +=
126 psock->stats.tx_msgs - psock->saved_tx_msgs;
127 psock->saved_tx_msgs = psock->stats.tx_msgs;
128 psock->saved_tx_bytes = psock->stats.tx_bytes;
129 }
130
131 static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
132
133 /* KCM is ready to receive messages on its queue-- either the KCM is new or
134 * has become unblocked after being blocked on full socket buffer. Queue any
135 * pending ready messages on a psock. RX mux lock held.
136 */
137 static void kcm_rcv_ready(struct kcm_sock *kcm)
138 {
139 struct kcm_mux *mux = kcm->mux;
140 struct kcm_psock *psock;
141 struct sk_buff *skb;
142
143 if (unlikely(kcm->rx_wait || kcm->rx_psock || kcm->rx_disabled))
144 return;
145
146 while (unlikely((skb = __skb_dequeue(&mux->rx_hold_queue)))) {
147 if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
148 /* Assuming buffer limit has been reached */
149 skb_queue_head(&mux->rx_hold_queue, skb);
150 WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
151 return;
152 }
153 }
154
155 while (!list_empty(&mux->psocks_ready)) {
156 psock = list_first_entry(&mux->psocks_ready, struct kcm_psock,
157 psock_ready_list);
158
159 if (kcm_queue_rcv_skb(&kcm->sk, psock->ready_rx_msg)) {
160 /* Assuming buffer limit has been reached */
161 WARN_ON(!sk_rmem_alloc_get(&kcm->sk));
162 return;
163 }
164
165 /* Consumed the ready message on the psock. Schedule rx_work to
166 * get more messages.
167 */
168 list_del(&psock->psock_ready_list);
169 psock->ready_rx_msg = NULL;
170
171 /* Commit clearing of ready_rx_msg for queuing work */
172 smp_mb();
173
174 queue_work(kcm_wq, &psock->rx_work);
175 }
176
177 /* Buffer limit is okay now, add to ready list */
178 list_add_tail(&kcm->wait_rx_list,
179 &kcm->mux->kcm_rx_waiters);
180 kcm->rx_wait = true;
181 }
182
183 static void kcm_rfree(struct sk_buff *skb)
184 {
185 struct sock *sk = skb->sk;
186 struct kcm_sock *kcm = kcm_sk(sk);
187 struct kcm_mux *mux = kcm->mux;
188 unsigned int len = skb->truesize;
189
190 sk_mem_uncharge(sk, len);
191 atomic_sub(len, &sk->sk_rmem_alloc);
192
193 /* For reading rx_wait and rx_psock without holding lock */
194 smp_mb__after_atomic();
195
196 if (!kcm->rx_wait && !kcm->rx_psock &&
197 sk_rmem_alloc_get(sk) < sk->sk_rcvlowat) {
198 spin_lock_bh(&mux->rx_lock);
199 kcm_rcv_ready(kcm);
200 spin_unlock_bh(&mux->rx_lock);
201 }
202 }
203
204 static int kcm_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
205 {
206 struct sk_buff_head *list = &sk->sk_receive_queue;
207
208 if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
209 return -ENOMEM;
210
211 if (!sk_rmem_schedule(sk, skb, skb->truesize))
212 return -ENOBUFS;
213
214 skb->dev = NULL;
215
216 skb_orphan(skb);
217 skb->sk = sk;
218 skb->destructor = kcm_rfree;
219 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
220 sk_mem_charge(sk, skb->truesize);
221
222 skb_queue_tail(list, skb);
223
224 if (!sock_flag(sk, SOCK_DEAD))
225 sk->sk_data_ready(sk);
226
227 return 0;
228 }
229
230 /* Requeue received messages for a kcm socket to other kcm sockets. This is
231 * called with a kcm socket is receive disabled.
232 * RX mux lock held.
233 */
234 static void requeue_rx_msgs(struct kcm_mux *mux, struct sk_buff_head *head)
235 {
236 struct sk_buff *skb;
237 struct kcm_sock *kcm;
238
239 while ((skb = __skb_dequeue(head))) {
240 /* Reset destructor to avoid calling kcm_rcv_ready */
241 skb->destructor = sock_rfree;
242 skb_orphan(skb);
243 try_again:
244 if (list_empty(&mux->kcm_rx_waiters)) {
245 skb_queue_tail(&mux->rx_hold_queue, skb);
246 continue;
247 }
248
249 kcm = list_first_entry(&mux->kcm_rx_waiters,
250 struct kcm_sock, wait_rx_list);
251
252 if (kcm_queue_rcv_skb(&kcm->sk, skb)) {
253 /* Should mean socket buffer full */
254 list_del(&kcm->wait_rx_list);
255 kcm->rx_wait = false;
256
257 /* Commit rx_wait to read in kcm_free */
258 smp_wmb();
259
260 goto try_again;
261 }
262 }
263 }
264
265 /* Lower sock lock held */
266 static struct kcm_sock *reserve_rx_kcm(struct kcm_psock *psock,
267 struct sk_buff *head)
268 {
269 struct kcm_mux *mux = psock->mux;
270 struct kcm_sock *kcm;
271
272 WARN_ON(psock->ready_rx_msg);
273
274 if (psock->rx_kcm)
275 return psock->rx_kcm;
276
277 spin_lock_bh(&mux->rx_lock);
278
279 if (psock->rx_kcm) {
280 spin_unlock_bh(&mux->rx_lock);
281 return psock->rx_kcm;
282 }
283
284 kcm_update_rx_mux_stats(mux, psock);
285
286 if (list_empty(&mux->kcm_rx_waiters)) {
287 psock->ready_rx_msg = head;
288 list_add_tail(&psock->psock_ready_list,
289 &mux->psocks_ready);
290 spin_unlock_bh(&mux->rx_lock);
291 return NULL;
292 }
293
294 kcm = list_first_entry(&mux->kcm_rx_waiters,
295 struct kcm_sock, wait_rx_list);
296 list_del(&kcm->wait_rx_list);
297 kcm->rx_wait = false;
298
299 psock->rx_kcm = kcm;
300 kcm->rx_psock = psock;
301
302 spin_unlock_bh(&mux->rx_lock);
303
304 return kcm;
305 }
306
307 static void kcm_done(struct kcm_sock *kcm);
308
309 static void kcm_done_work(struct work_struct *w)
310 {
311 kcm_done(container_of(w, struct kcm_sock, done_work));
312 }
313
314 /* Lower sock held */
315 static void unreserve_rx_kcm(struct kcm_psock *psock,
316 bool rcv_ready)
317 {
318 struct kcm_sock *kcm = psock->rx_kcm;
319 struct kcm_mux *mux = psock->mux;
320
321 if (!kcm)
322 return;
323
324 spin_lock_bh(&mux->rx_lock);
325
326 psock->rx_kcm = NULL;
327 kcm->rx_psock = NULL;
328
329 /* Commit kcm->rx_psock before sk_rmem_alloc_get to sync with
330 * kcm_rfree
331 */
332 smp_mb();
333
334 if (unlikely(kcm->done)) {
335 spin_unlock_bh(&mux->rx_lock);
336
337 /* Need to run kcm_done in a task since we need to qcquire
338 * callback locks which may already be held here.
339 */
340 INIT_WORK(&kcm->done_work, kcm_done_work);
341 schedule_work(&kcm->done_work);
342 return;
343 }
344
345 if (unlikely(kcm->rx_disabled)) {
346 requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
347 } else if (rcv_ready || unlikely(!sk_rmem_alloc_get(&kcm->sk))) {
348 /* Check for degenerative race with rx_wait that all
349 * data was dequeued (accounted for in kcm_rfree).
350 */
351 kcm_rcv_ready(kcm);
352 }
353 spin_unlock_bh(&mux->rx_lock);
354 }
355
356 static void kcm_start_rx_timer(struct kcm_psock *psock)
357 {
358 if (psock->sk->sk_rcvtimeo)
359 mod_timer(&psock->rx_msg_timer, psock->sk->sk_rcvtimeo);
360 }
361
362 /* Macro to invoke filter function. */
363 #define KCM_RUN_FILTER(prog, ctx) \
364 (*prog->bpf_func)(ctx, prog->insnsi)
365
366 /* Lower socket lock held */
367 static int kcm_tcp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
368 unsigned int orig_offset, size_t orig_len)
369 {
370 struct kcm_psock *psock = (struct kcm_psock *)desc->arg.data;
371 struct kcm_rx_msg *rxm;
372 struct kcm_sock *kcm;
373 struct sk_buff *head, *skb;
374 size_t eaten = 0, cand_len;
375 ssize_t extra;
376 int err;
377 bool cloned_orig = false;
378
379 if (psock->ready_rx_msg)
380 return 0;
381
382 head = psock->rx_skb_head;
383 if (head) {
384 /* Message already in progress */
385
386 rxm = kcm_rx_msg(head);
387 if (unlikely(rxm->early_eaten)) {
388 /* Already some number of bytes on the receive sock
389 * data saved in rx_skb_head, just indicate they
390 * are consumed.
391 */
392 eaten = orig_len <= rxm->early_eaten ?
393 orig_len : rxm->early_eaten;
394 rxm->early_eaten -= eaten;
395
396 return eaten;
397 }
398
399 if (unlikely(orig_offset)) {
400 /* Getting data with a non-zero offset when a message is
401 * in progress is not expected. If it does happen, we
402 * need to clone and pull since we can't deal with
403 * offsets in the skbs for a message expect in the head.
404 */
405 orig_skb = skb_clone(orig_skb, GFP_ATOMIC);
406 if (!orig_skb) {
407 KCM_STATS_INCR(psock->stats.rx_mem_fail);
408 desc->error = -ENOMEM;
409 return 0;
410 }
411 if (!pskb_pull(orig_skb, orig_offset)) {
412 KCM_STATS_INCR(psock->stats.rx_mem_fail);
413 kfree_skb(orig_skb);
414 desc->error = -ENOMEM;
415 return 0;
416 }
417 cloned_orig = true;
418 orig_offset = 0;
419 }
420
421 if (!psock->rx_skb_nextp) {
422 /* We are going to append to the frags_list of head.
423 * Need to unshare the frag_list.
424 */
425 err = skb_unclone(head, GFP_ATOMIC);
426 if (err) {
427 KCM_STATS_INCR(psock->stats.rx_mem_fail);
428 desc->error = err;
429 return 0;
430 }
431
432 if (unlikely(skb_shinfo(head)->frag_list)) {
433 /* We can't append to an sk_buff that already
434 * has a frag_list. We create a new head, point
435 * the frag_list of that to the old head, and
436 * then are able to use the old head->next for
437 * appending to the message.
438 */
439 if (WARN_ON(head->next)) {
440 desc->error = -EINVAL;
441 return 0;
442 }
443
444 skb = alloc_skb(0, GFP_ATOMIC);
445 if (!skb) {
446 KCM_STATS_INCR(psock->stats.rx_mem_fail);
447 desc->error = -ENOMEM;
448 return 0;
449 }
450 skb->len = head->len;
451 skb->data_len = head->len;
452 skb->truesize = head->truesize;
453 *kcm_rx_msg(skb) = *kcm_rx_msg(head);
454 psock->rx_skb_nextp = &head->next;
455 skb_shinfo(skb)->frag_list = head;
456 psock->rx_skb_head = skb;
457 head = skb;
458 } else {
459 psock->rx_skb_nextp =
460 &skb_shinfo(head)->frag_list;
461 }
462 }
463 }
464
465 while (eaten < orig_len) {
466 /* Always clone since we will consume something */
467 skb = skb_clone(orig_skb, GFP_ATOMIC);
468 if (!skb) {
469 KCM_STATS_INCR(psock->stats.rx_mem_fail);
470 desc->error = -ENOMEM;
471 break;
472 }
473
474 cand_len = orig_len - eaten;
475
476 head = psock->rx_skb_head;
477 if (!head) {
478 head = skb;
479 psock->rx_skb_head = head;
480 /* Will set rx_skb_nextp on next packet if needed */
481 psock->rx_skb_nextp = NULL;
482 rxm = kcm_rx_msg(head);
483 memset(rxm, 0, sizeof(*rxm));
484 rxm->offset = orig_offset + eaten;
485 } else {
486 /* Unclone since we may be appending to an skb that we
487 * already share a frag_list with.
488 */
489 err = skb_unclone(skb, GFP_ATOMIC);
490 if (err) {
491 KCM_STATS_INCR(psock->stats.rx_mem_fail);
492 desc->error = err;
493 break;
494 }
495
496 rxm = kcm_rx_msg(head);
497 *psock->rx_skb_nextp = skb;
498 psock->rx_skb_nextp = &skb->next;
499 head->data_len += skb->len;
500 head->len += skb->len;
501 head->truesize += skb->truesize;
502 }
503
504 if (!rxm->full_len) {
505 ssize_t len;
506
507 len = KCM_RUN_FILTER(psock->bpf_prog, head);
508
509 if (!len) {
510 /* Need more header to determine length */
511 if (!rxm->accum_len) {
512 /* Start RX timer for new message */
513 kcm_start_rx_timer(psock);
514 }
515 rxm->accum_len += cand_len;
516 eaten += cand_len;
517 KCM_STATS_INCR(psock->stats.rx_need_more_hdr);
518 WARN_ON(eaten != orig_len);
519 break;
520 } else if (len > psock->sk->sk_rcvbuf) {
521 /* Message length exceeds maximum allowed */
522 KCM_STATS_INCR(psock->stats.rx_msg_too_big);
523 desc->error = -EMSGSIZE;
524 psock->rx_skb_head = NULL;
525 kcm_abort_rx_psock(psock, EMSGSIZE, head);
526 break;
527 } else if (len <= (ssize_t)head->len -
528 skb->len - rxm->offset) {
529 /* Length must be into new skb (and also
530 * greater than zero)
531 */
532 KCM_STATS_INCR(psock->stats.rx_bad_hdr_len);
533 desc->error = -EPROTO;
534 psock->rx_skb_head = NULL;
535 kcm_abort_rx_psock(psock, EPROTO, head);
536 break;
537 }
538
539 rxm->full_len = len;
540 }
541
542 extra = (ssize_t)(rxm->accum_len + cand_len) - rxm->full_len;
543
544 if (extra < 0) {
545 /* Message not complete yet. */
546 if (rxm->full_len - rxm->accum_len >
547 tcp_inq(psock->sk)) {
548 /* Don't have the whole messages in the socket
549 * buffer. Set psock->rx_need_bytes to wait for
550 * the rest of the message. Also, set "early
551 * eaten" since we've already buffered the skb
552 * but don't consume yet per tcp_read_sock.
553 */
554
555 if (!rxm->accum_len) {
556 /* Start RX timer for new message */
557 kcm_start_rx_timer(psock);
558 }
559
560 psock->rx_need_bytes = rxm->full_len -
561 rxm->accum_len;
562 rxm->accum_len += cand_len;
563 rxm->early_eaten = cand_len;
564 KCM_STATS_ADD(psock->stats.rx_bytes, cand_len);
565 desc->count = 0; /* Stop reading socket */
566 break;
567 }
568 rxm->accum_len += cand_len;
569 eaten += cand_len;
570 WARN_ON(eaten != orig_len);
571 break;
572 }
573
574 /* Positive extra indicates ore bytes than needed for the
575 * message
576 */
577
578 WARN_ON(extra > cand_len);
579
580 eaten += (cand_len - extra);
581
582 /* Hurray, we have a new message! */
583 del_timer(&psock->rx_msg_timer);
584 psock->rx_skb_head = NULL;
585 KCM_STATS_INCR(psock->stats.rx_msgs);
586
587 try_queue:
588 kcm = reserve_rx_kcm(psock, head);
589 if (!kcm) {
590 /* Unable to reserve a KCM, message is held in psock. */
591 break;
592 }
593
594 if (kcm_queue_rcv_skb(&kcm->sk, head)) {
595 /* Should mean socket buffer full */
596 unreserve_rx_kcm(psock, false);
597 goto try_queue;
598 }
599 }
600
601 if (cloned_orig)
602 kfree_skb(orig_skb);
603
604 KCM_STATS_ADD(psock->stats.rx_bytes, eaten);
605
606 return eaten;
607 }
608
609 /* Called with lock held on lower socket */
610 static int psock_tcp_read_sock(struct kcm_psock *psock)
611 {
612 read_descriptor_t desc;
613
614 desc.arg.data = psock;
615 desc.error = 0;
616 desc.count = 1; /* give more than one skb per call */
617
618 /* sk should be locked here, so okay to do tcp_read_sock */
619 tcp_read_sock(psock->sk, &desc, kcm_tcp_recv);
620
621 unreserve_rx_kcm(psock, true);
622
623 return desc.error;
624 }
625
626 /* Lower sock lock held */
627 static void psock_tcp_data_ready(struct sock *sk)
628 {
629 struct kcm_psock *psock;
630
631 read_lock_bh(&sk->sk_callback_lock);
632
633 psock = (struct kcm_psock *)sk->sk_user_data;
634 if (unlikely(!psock || psock->rx_stopped))
635 goto out;
636
637 if (psock->ready_rx_msg)
638 goto out;
639
640 if (psock->rx_need_bytes) {
641 if (tcp_inq(sk) >= psock->rx_need_bytes)
642 psock->rx_need_bytes = 0;
643 else
644 goto out;
645 }
646
647 if (psock_tcp_read_sock(psock) == -ENOMEM)
648 queue_delayed_work(kcm_wq, &psock->rx_delayed_work, 0);
649
650 out:
651 read_unlock_bh(&sk->sk_callback_lock);
652 }
653
654 static void do_psock_rx_work(struct kcm_psock *psock)
655 {
656 read_descriptor_t rd_desc;
657 struct sock *csk = psock->sk;
658
659 /* We need the read lock to synchronize with psock_tcp_data_ready. We
660 * need the socket lock for calling tcp_read_sock.
661 */
662 lock_sock(csk);
663 read_lock_bh(&csk->sk_callback_lock);
664
665 if (unlikely(csk->sk_user_data != psock))
666 goto out;
667
668 if (unlikely(psock->rx_stopped))
669 goto out;
670
671 if (psock->ready_rx_msg)
672 goto out;
673
674 rd_desc.arg.data = psock;
675
676 if (psock_tcp_read_sock(psock) == -ENOMEM)
677 queue_delayed_work(kcm_wq, &psock->rx_delayed_work, 0);
678
679 out:
680 read_unlock_bh(&csk->sk_callback_lock);
681 release_sock(csk);
682 }
683
684 static void psock_rx_work(struct work_struct *w)
685 {
686 do_psock_rx_work(container_of(w, struct kcm_psock, rx_work));
687 }
688
689 static void psock_rx_delayed_work(struct work_struct *w)
690 {
691 do_psock_rx_work(container_of(w, struct kcm_psock,
692 rx_delayed_work.work));
693 }
694
695 static void psock_tcp_state_change(struct sock *sk)
696 {
697 /* TCP only does a POLLIN for a half close. Do a POLLHUP here
698 * since application will normally not poll with POLLIN
699 * on the TCP sockets.
700 */
701
702 report_csk_error(sk, EPIPE);
703 }
704
705 static void psock_tcp_write_space(struct sock *sk)
706 {
707 struct kcm_psock *psock;
708 struct kcm_mux *mux;
709 struct kcm_sock *kcm;
710
711 read_lock_bh(&sk->sk_callback_lock);
712
713 psock = (struct kcm_psock *)sk->sk_user_data;
714 if (unlikely(!psock))
715 goto out;
716
717 mux = psock->mux;
718
719 spin_lock_bh(&mux->lock);
720
721 /* Check if the socket is reserved so someone is waiting for sending. */
722 kcm = psock->tx_kcm;
723 if (kcm)
724 queue_work(kcm_wq, &kcm->tx_work);
725
726 spin_unlock_bh(&mux->lock);
727 out:
728 read_unlock_bh(&sk->sk_callback_lock);
729 }
730
731 static void unreserve_psock(struct kcm_sock *kcm);
732
733 /* kcm sock is locked. */
734 static struct kcm_psock *reserve_psock(struct kcm_sock *kcm)
735 {
736 struct kcm_mux *mux = kcm->mux;
737 struct kcm_psock *psock;
738
739 psock = kcm->tx_psock;
740
741 smp_rmb(); /* Must read tx_psock before tx_wait */
742
743 if (psock) {
744 WARN_ON(kcm->tx_wait);
745 if (unlikely(psock->tx_stopped))
746 unreserve_psock(kcm);
747 else
748 return kcm->tx_psock;
749 }
750
751 spin_lock_bh(&mux->lock);
752
753 /* Check again under lock to see if psock was reserved for this
754 * psock via psock_unreserve.
755 */
756 psock = kcm->tx_psock;
757 if (unlikely(psock)) {
758 WARN_ON(kcm->tx_wait);
759 spin_unlock_bh(&mux->lock);
760 return kcm->tx_psock;
761 }
762
763 if (!list_empty(&mux->psocks_avail)) {
764 psock = list_first_entry(&mux->psocks_avail,
765 struct kcm_psock,
766 psock_avail_list);
767 list_del(&psock->psock_avail_list);
768 if (kcm->tx_wait) {
769 list_del(&kcm->wait_psock_list);
770 kcm->tx_wait = false;
771 }
772 kcm->tx_psock = psock;
773 psock->tx_kcm = kcm;
774 KCM_STATS_INCR(psock->stats.reserved);
775 } else if (!kcm->tx_wait) {
776 list_add_tail(&kcm->wait_psock_list,
777 &mux->kcm_tx_waiters);
778 kcm->tx_wait = true;
779 }
780
781 spin_unlock_bh(&mux->lock);
782
783 return psock;
784 }
785
786 /* mux lock held */
787 static void psock_now_avail(struct kcm_psock *psock)
788 {
789 struct kcm_mux *mux = psock->mux;
790 struct kcm_sock *kcm;
791
792 if (list_empty(&mux->kcm_tx_waiters)) {
793 list_add_tail(&psock->psock_avail_list,
794 &mux->psocks_avail);
795 } else {
796 kcm = list_first_entry(&mux->kcm_tx_waiters,
797 struct kcm_sock,
798 wait_psock_list);
799 list_del(&kcm->wait_psock_list);
800 kcm->tx_wait = false;
801 psock->tx_kcm = kcm;
802
803 /* Commit before changing tx_psock since that is read in
804 * reserve_psock before queuing work.
805 */
806 smp_mb();
807
808 kcm->tx_psock = psock;
809 KCM_STATS_INCR(psock->stats.reserved);
810 queue_work(kcm_wq, &kcm->tx_work);
811 }
812 }
813
814 /* kcm sock is locked. */
815 static void unreserve_psock(struct kcm_sock *kcm)
816 {
817 struct kcm_psock *psock;
818 struct kcm_mux *mux = kcm->mux;
819
820 spin_lock_bh(&mux->lock);
821
822 psock = kcm->tx_psock;
823
824 if (WARN_ON(!psock)) {
825 spin_unlock_bh(&mux->lock);
826 return;
827 }
828
829 smp_rmb(); /* Read tx_psock before tx_wait */
830
831 kcm_update_tx_mux_stats(mux, psock);
832
833 WARN_ON(kcm->tx_wait);
834
835 kcm->tx_psock = NULL;
836 psock->tx_kcm = NULL;
837 KCM_STATS_INCR(psock->stats.unreserved);
838
839 if (unlikely(psock->tx_stopped)) {
840 if (psock->done) {
841 /* Deferred free */
842 list_del(&psock->psock_list);
843 mux->psocks_cnt--;
844 sock_put(psock->sk);
845 fput(psock->sk->sk_socket->file);
846 kmem_cache_free(kcm_psockp, psock);
847 }
848
849 /* Don't put back on available list */
850
851 spin_unlock_bh(&mux->lock);
852
853 return;
854 }
855
856 psock_now_avail(psock);
857
858 spin_unlock_bh(&mux->lock);
859 }
860
861 static void kcm_report_tx_retry(struct kcm_sock *kcm)
862 {
863 struct kcm_mux *mux = kcm->mux;
864
865 spin_lock_bh(&mux->lock);
866 KCM_STATS_INCR(mux->stats.tx_retries);
867 spin_unlock_bh(&mux->lock);
868 }
869
870 /* Write any messages ready on the kcm socket. Called with kcm sock lock
871 * held. Return bytes actually sent or error.
872 */
873 static int kcm_write_msgs(struct kcm_sock *kcm)
874 {
875 struct sock *sk = &kcm->sk;
876 struct kcm_psock *psock;
877 struct sk_buff *skb, *head;
878 struct kcm_tx_msg *txm;
879 unsigned short fragidx, frag_offset;
880 unsigned int sent, total_sent = 0;
881 int ret = 0;
882
883 kcm->tx_wait_more = false;
884 psock = kcm->tx_psock;
885 if (unlikely(psock && psock->tx_stopped)) {
886 /* A reserved psock was aborted asynchronously. Unreserve
887 * it and we'll retry the message.
888 */
889 unreserve_psock(kcm);
890 kcm_report_tx_retry(kcm);
891 if (skb_queue_empty(&sk->sk_write_queue))
892 return 0;
893
894 kcm_tx_msg(skb_peek(&sk->sk_write_queue))->sent = 0;
895
896 } else if (skb_queue_empty(&sk->sk_write_queue)) {
897 return 0;
898 }
899
900 head = skb_peek(&sk->sk_write_queue);
901 txm = kcm_tx_msg(head);
902
903 if (txm->sent) {
904 /* Send of first skbuff in queue already in progress */
905 if (WARN_ON(!psock)) {
906 ret = -EINVAL;
907 goto out;
908 }
909 sent = txm->sent;
910 frag_offset = txm->frag_offset;
911 fragidx = txm->fragidx;
912 skb = txm->frag_skb;
913
914 goto do_frag;
915 }
916
917 try_again:
918 psock = reserve_psock(kcm);
919 if (!psock)
920 goto out;
921
922 do {
923 skb = head;
924 txm = kcm_tx_msg(head);
925 sent = 0;
926
927 do_frag_list:
928 if (WARN_ON(!skb_shinfo(skb)->nr_frags)) {
929 ret = -EINVAL;
930 goto out;
931 }
932
933 for (fragidx = 0; fragidx < skb_shinfo(skb)->nr_frags;
934 fragidx++) {
935 skb_frag_t *frag;
936
937 frag_offset = 0;
938 do_frag:
939 frag = &skb_shinfo(skb)->frags[fragidx];
940 if (WARN_ON(!frag->size)) {
941 ret = -EINVAL;
942 goto out;
943 }
944
945 ret = kernel_sendpage(psock->sk->sk_socket,
946 frag->page.p,
947 frag->page_offset + frag_offset,
948 frag->size - frag_offset,
949 MSG_DONTWAIT);
950 if (ret <= 0) {
951 if (ret == -EAGAIN) {
952 /* Save state to try again when there's
953 * write space on the socket
954 */
955 txm->sent = sent;
956 txm->frag_offset = frag_offset;
957 txm->fragidx = fragidx;
958 txm->frag_skb = skb;
959
960 ret = 0;
961 goto out;
962 }
963
964 /* Hard failure in sending message, abort this
965 * psock since it has lost framing
966 * synchonization and retry sending the
967 * message from the beginning.
968 */
969 kcm_abort_tx_psock(psock, ret ? -ret : EPIPE,
970 true);
971 unreserve_psock(kcm);
972
973 txm->sent = 0;
974 kcm_report_tx_retry(kcm);
975 ret = 0;
976
977 goto try_again;
978 }
979
980 sent += ret;
981 frag_offset += ret;
982 KCM_STATS_ADD(psock->stats.tx_bytes, ret);
983 if (frag_offset < frag->size) {
984 /* Not finished with this frag */
985 goto do_frag;
986 }
987 }
988
989 if (skb == head) {
990 if (skb_has_frag_list(skb)) {
991 skb = skb_shinfo(skb)->frag_list;
992 goto do_frag_list;
993 }
994 } else if (skb->next) {
995 skb = skb->next;
996 goto do_frag_list;
997 }
998
999 /* Successfully sent the whole packet, account for it. */
1000 skb_dequeue(&sk->sk_write_queue);
1001 kfree_skb(head);
1002 sk->sk_wmem_queued -= sent;
1003 total_sent += sent;
1004 KCM_STATS_INCR(psock->stats.tx_msgs);
1005 } while ((head = skb_peek(&sk->sk_write_queue)));
1006 out:
1007 if (!head) {
1008 /* Done with all queued messages. */
1009 WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
1010 unreserve_psock(kcm);
1011 }
1012
1013 /* Check if write space is available */
1014 sk->sk_write_space(sk);
1015
1016 return total_sent ? : ret;
1017 }
1018
1019 static void kcm_tx_work(struct work_struct *w)
1020 {
1021 struct kcm_sock *kcm = container_of(w, struct kcm_sock, tx_work);
1022 struct sock *sk = &kcm->sk;
1023 int err;
1024
1025 lock_sock(sk);
1026
1027 /* Primarily for SOCK_DGRAM sockets, also handle asynchronous tx
1028 * aborts
1029 */
1030 err = kcm_write_msgs(kcm);
1031 if (err < 0) {
1032 /* Hard failure in write, report error on KCM socket */
1033 pr_warn("KCM: Hard failure on kcm_write_msgs %d\n", err);
1034 report_csk_error(&kcm->sk, -err);
1035 goto out;
1036 }
1037
1038 /* Primarily for SOCK_SEQPACKET sockets */
1039 if (likely(sk->sk_socket) &&
1040 test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1041 clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1042 sk->sk_write_space(sk);
1043 }
1044
1045 out:
1046 release_sock(sk);
1047 }
1048
1049 static void kcm_push(struct kcm_sock *kcm)
1050 {
1051 if (kcm->tx_wait_more)
1052 kcm_write_msgs(kcm);
1053 }
1054
1055 static ssize_t kcm_sendpage(struct socket *sock, struct page *page,
1056 int offset, size_t size, int flags)
1057
1058 {
1059 struct sock *sk = sock->sk;
1060 struct kcm_sock *kcm = kcm_sk(sk);
1061 struct sk_buff *skb = NULL, *head = NULL;
1062 long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
1063 bool eor;
1064 int err = 0;
1065 int i;
1066
1067 if (flags & MSG_SENDPAGE_NOTLAST)
1068 flags |= MSG_MORE;
1069
1070 /* No MSG_EOR from splice, only look at MSG_MORE */
1071 eor = !(flags & MSG_MORE);
1072
1073 lock_sock(sk);
1074
1075 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
1076
1077 err = -EPIPE;
1078 if (sk->sk_err)
1079 goto out_error;
1080
1081 if (kcm->seq_skb) {
1082 /* Previously opened message */
1083 head = kcm->seq_skb;
1084 skb = kcm_tx_msg(head)->last_skb;
1085 i = skb_shinfo(skb)->nr_frags;
1086
1087 if (skb_can_coalesce(skb, i, page, offset)) {
1088 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
1089 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1090 goto coalesced;
1091 }
1092
1093 if (i >= MAX_SKB_FRAGS) {
1094 struct sk_buff *tskb;
1095
1096 tskb = alloc_skb(0, sk->sk_allocation);
1097 while (!tskb) {
1098 kcm_push(kcm);
1099 err = sk_stream_wait_memory(sk, &timeo);
1100 if (err)
1101 goto out_error;
1102 }
1103
1104 if (head == skb)
1105 skb_shinfo(head)->frag_list = tskb;
1106 else
1107 skb->next = tskb;
1108
1109 skb = tskb;
1110 skb->ip_summed = CHECKSUM_UNNECESSARY;
1111 i = 0;
1112 }
1113 } else {
1114 /* Call the sk_stream functions to manage the sndbuf mem. */
1115 if (!sk_stream_memory_free(sk)) {
1116 kcm_push(kcm);
1117 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1118 err = sk_stream_wait_memory(sk, &timeo);
1119 if (err)
1120 goto out_error;
1121 }
1122
1123 head = alloc_skb(0, sk->sk_allocation);
1124 while (!head) {
1125 kcm_push(kcm);
1126 err = sk_stream_wait_memory(sk, &timeo);
1127 if (err)
1128 goto out_error;
1129 }
1130
1131 skb = head;
1132 i = 0;
1133 }
1134
1135 get_page(page);
1136 skb_fill_page_desc(skb, i, page, offset, size);
1137 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
1138
1139 coalesced:
1140 skb->len += size;
1141 skb->data_len += size;
1142 skb->truesize += size;
1143 sk->sk_wmem_queued += size;
1144 sk_mem_charge(sk, size);
1145
1146 if (head != skb) {
1147 head->len += size;
1148 head->data_len += size;
1149 head->truesize += size;
1150 }
1151
1152 if (eor) {
1153 bool not_busy = skb_queue_empty(&sk->sk_write_queue);
1154
1155 /* Message complete, queue it on send buffer */
1156 __skb_queue_tail(&sk->sk_write_queue, head);
1157 kcm->seq_skb = NULL;
1158 KCM_STATS_INCR(kcm->stats.tx_msgs);
1159
1160 if (flags & MSG_BATCH) {
1161 kcm->tx_wait_more = true;
1162 } else if (kcm->tx_wait_more || not_busy) {
1163 err = kcm_write_msgs(kcm);
1164 if (err < 0) {
1165 /* We got a hard error in write_msgs but have
1166 * already queued this message. Report an error
1167 * in the socket, but don't affect return value
1168 * from sendmsg
1169 */
1170 pr_warn("KCM: Hard failure on kcm_write_msgs\n");
1171 report_csk_error(&kcm->sk, -err);
1172 }
1173 }
1174 } else {
1175 /* Message not complete, save state */
1176 kcm->seq_skb = head;
1177 kcm_tx_msg(head)->last_skb = skb;
1178 }
1179
1180 KCM_STATS_ADD(kcm->stats.tx_bytes, size);
1181
1182 release_sock(sk);
1183 return size;
1184
1185 out_error:
1186 kcm_push(kcm);
1187
1188 err = sk_stream_error(sk, flags, err);
1189
1190 /* make sure we wake any epoll edge trigger waiter */
1191 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
1192 sk->sk_write_space(sk);
1193
1194 release_sock(sk);
1195 return err;
1196 }
1197
1198 static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
1199 {
1200 struct sock *sk = sock->sk;
1201 struct kcm_sock *kcm = kcm_sk(sk);
1202 struct sk_buff *skb = NULL, *head = NULL;
1203 size_t copy, copied = 0;
1204 long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
1205 int eor = (sock->type == SOCK_DGRAM) ?
1206 !(msg->msg_flags & MSG_MORE) : !!(msg->msg_flags & MSG_EOR);
1207 int err = -EPIPE;
1208
1209 lock_sock(sk);
1210
1211 /* Per tcp_sendmsg this should be in poll */
1212 sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
1213
1214 if (sk->sk_err)
1215 goto out_error;
1216
1217 if (kcm->seq_skb) {
1218 /* Previously opened message */
1219 head = kcm->seq_skb;
1220 skb = kcm_tx_msg(head)->last_skb;
1221 goto start;
1222 }
1223
1224 /* Call the sk_stream functions to manage the sndbuf mem. */
1225 if (!sk_stream_memory_free(sk)) {
1226 kcm_push(kcm);
1227 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1228 err = sk_stream_wait_memory(sk, &timeo);
1229 if (err)
1230 goto out_error;
1231 }
1232
1233 /* New message, alloc head skb */
1234 head = alloc_skb(0, sk->sk_allocation);
1235 while (!head) {
1236 kcm_push(kcm);
1237 err = sk_stream_wait_memory(sk, &timeo);
1238 if (err)
1239 goto out_error;
1240
1241 head = alloc_skb(0, sk->sk_allocation);
1242 }
1243
1244 skb = head;
1245
1246 /* Set ip_summed to CHECKSUM_UNNECESSARY to avoid calling
1247 * csum_and_copy_from_iter from skb_do_copy_data_nocache.
1248 */
1249 skb->ip_summed = CHECKSUM_UNNECESSARY;
1250
1251 start:
1252 while (msg_data_left(msg)) {
1253 bool merge = true;
1254 int i = skb_shinfo(skb)->nr_frags;
1255 struct page_frag *pfrag = sk_page_frag(sk);
1256
1257 if (!sk_page_frag_refill(sk, pfrag))
1258 goto wait_for_memory;
1259
1260 if (!skb_can_coalesce(skb, i, pfrag->page,
1261 pfrag->offset)) {
1262 if (i == MAX_SKB_FRAGS) {
1263 struct sk_buff *tskb;
1264
1265 tskb = alloc_skb(0, sk->sk_allocation);
1266 if (!tskb)
1267 goto wait_for_memory;
1268
1269 if (head == skb)
1270 skb_shinfo(head)->frag_list = tskb;
1271 else
1272 skb->next = tskb;
1273
1274 skb = tskb;
1275 skb->ip_summed = CHECKSUM_UNNECESSARY;
1276 continue;
1277 }
1278 merge = false;
1279 }
1280
1281 copy = min_t(int, msg_data_left(msg),
1282 pfrag->size - pfrag->offset);
1283
1284 if (!sk_wmem_schedule(sk, copy))
1285 goto wait_for_memory;
1286
1287 err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
1288 pfrag->page,
1289 pfrag->offset,
1290 copy);
1291 if (err)
1292 goto out_error;
1293
1294 /* Update the skb. */
1295 if (merge) {
1296 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1297 } else {
1298 skb_fill_page_desc(skb, i, pfrag->page,
1299 pfrag->offset, copy);
1300 get_page(pfrag->page);
1301 }
1302
1303 pfrag->offset += copy;
1304 copied += copy;
1305 if (head != skb) {
1306 head->len += copy;
1307 head->data_len += copy;
1308 }
1309
1310 continue;
1311
1312 wait_for_memory:
1313 kcm_push(kcm);
1314 err = sk_stream_wait_memory(sk, &timeo);
1315 if (err)
1316 goto out_error;
1317 }
1318
1319 if (eor) {
1320 bool not_busy = skb_queue_empty(&sk->sk_write_queue);
1321
1322 /* Message complete, queue it on send buffer */
1323 __skb_queue_tail(&sk->sk_write_queue, head);
1324 kcm->seq_skb = NULL;
1325 KCM_STATS_INCR(kcm->stats.tx_msgs);
1326
1327 if (msg->msg_flags & MSG_BATCH) {
1328 kcm->tx_wait_more = true;
1329 } else if (kcm->tx_wait_more || not_busy) {
1330 err = kcm_write_msgs(kcm);
1331 if (err < 0) {
1332 /* We got a hard error in write_msgs but have
1333 * already queued this message. Report an error
1334 * in the socket, but don't affect return value
1335 * from sendmsg
1336 */
1337 pr_warn("KCM: Hard failure on kcm_write_msgs\n");
1338 report_csk_error(&kcm->sk, -err);
1339 }
1340 }
1341 } else {
1342 /* Message not complete, save state */
1343 partial_message:
1344 kcm->seq_skb = head;
1345 kcm_tx_msg(head)->last_skb = skb;
1346 }
1347
1348 KCM_STATS_ADD(kcm->stats.tx_bytes, copied);
1349
1350 release_sock(sk);
1351 return copied;
1352
1353 out_error:
1354 kcm_push(kcm);
1355
1356 if (copied && sock->type == SOCK_SEQPACKET) {
1357 /* Wrote some bytes before encountering an
1358 * error, return partial success.
1359 */
1360 goto partial_message;
1361 }
1362
1363 if (head != kcm->seq_skb)
1364 kfree_skb(head);
1365
1366 err = sk_stream_error(sk, msg->msg_flags, err);
1367
1368 /* make sure we wake any epoll edge trigger waiter */
1369 if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
1370 sk->sk_write_space(sk);
1371
1372 release_sock(sk);
1373 return err;
1374 }
1375
1376 static struct sk_buff *kcm_wait_data(struct sock *sk, int flags,
1377 long timeo, int *err)
1378 {
1379 struct sk_buff *skb;
1380
1381 while (!(skb = skb_peek(&sk->sk_receive_queue))) {
1382 if (sk->sk_err) {
1383 *err = sock_error(sk);
1384 return NULL;
1385 }
1386
1387 if (sock_flag(sk, SOCK_DONE))
1388 return NULL;
1389
1390 if ((flags & MSG_DONTWAIT) || !timeo) {
1391 *err = -EAGAIN;
1392 return NULL;
1393 }
1394
1395 sk_wait_data(sk, &timeo, NULL);
1396
1397 /* Handle signals */
1398 if (signal_pending(current)) {
1399 *err = sock_intr_errno(timeo);
1400 return NULL;
1401 }
1402 }
1403
1404 return skb;
1405 }
1406
1407 static int kcm_recvmsg(struct socket *sock, struct msghdr *msg,
1408 size_t len, int flags)
1409 {
1410 struct sock *sk = sock->sk;
1411 struct kcm_sock *kcm = kcm_sk(sk);
1412 int err = 0;
1413 long timeo;
1414 struct kcm_rx_msg *rxm;
1415 int copied = 0;
1416 struct sk_buff *skb;
1417
1418 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1419
1420 lock_sock(sk);
1421
1422 skb = kcm_wait_data(sk, flags, timeo, &err);
1423 if (!skb)
1424 goto out;
1425
1426 /* Okay, have a message on the receive queue */
1427
1428 rxm = kcm_rx_msg(skb);
1429
1430 if (len > rxm->full_len)
1431 len = rxm->full_len;
1432
1433 err = skb_copy_datagram_msg(skb, rxm->offset, msg, len);
1434 if (err < 0)
1435 goto out;
1436
1437 copied = len;
1438 if (likely(!(flags & MSG_PEEK))) {
1439 KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
1440 if (copied < rxm->full_len) {
1441 if (sock->type == SOCK_DGRAM) {
1442 /* Truncated message */
1443 msg->msg_flags |= MSG_TRUNC;
1444 goto msg_finished;
1445 }
1446 rxm->offset += copied;
1447 rxm->full_len -= copied;
1448 } else {
1449 msg_finished:
1450 /* Finished with message */
1451 msg->msg_flags |= MSG_EOR;
1452 KCM_STATS_INCR(kcm->stats.rx_msgs);
1453 skb_unlink(skb, &sk->sk_receive_queue);
1454 kfree_skb(skb);
1455 }
1456 }
1457
1458 out:
1459 release_sock(sk);
1460
1461 return copied ? : err;
1462 }
1463
1464 static ssize_t kcm_sock_splice(struct sock *sk,
1465 struct pipe_inode_info *pipe,
1466 struct splice_pipe_desc *spd)
1467 {
1468 int ret;
1469
1470 release_sock(sk);
1471 ret = splice_to_pipe(pipe, spd);
1472 lock_sock(sk);
1473
1474 return ret;
1475 }
1476
1477 static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
1478 struct pipe_inode_info *pipe, size_t len,
1479 unsigned int flags)
1480 {
1481 struct sock *sk = sock->sk;
1482 struct kcm_sock *kcm = kcm_sk(sk);
1483 long timeo;
1484 struct kcm_rx_msg *rxm;
1485 int err = 0;
1486 ssize_t copied;
1487 struct sk_buff *skb;
1488
1489 /* Only support splice for SOCKSEQPACKET */
1490
1491 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1492
1493 lock_sock(sk);
1494
1495 skb = kcm_wait_data(sk, flags, timeo, &err);
1496 if (!skb)
1497 goto err_out;
1498
1499 /* Okay, have a message on the receive queue */
1500
1501 rxm = kcm_rx_msg(skb);
1502
1503 if (len > rxm->full_len)
1504 len = rxm->full_len;
1505
1506 copied = skb_splice_bits(skb, sk, rxm->offset, pipe, len, flags,
1507 kcm_sock_splice);
1508 if (copied < 0) {
1509 err = copied;
1510 goto err_out;
1511 }
1512
1513 KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
1514
1515 rxm->offset += copied;
1516 rxm->full_len -= copied;
1517
1518 /* We have no way to return MSG_EOR. If all the bytes have been
1519 * read we still leave the message in the receive socket buffer.
1520 * A subsequent recvmsg needs to be done to return MSG_EOR and
1521 * finish reading the message.
1522 */
1523
1524 release_sock(sk);
1525
1526 return copied;
1527
1528 err_out:
1529 release_sock(sk);
1530
1531 return err;
1532 }
1533
1534 /* kcm sock lock held */
1535 static void kcm_recv_disable(struct kcm_sock *kcm)
1536 {
1537 struct kcm_mux *mux = kcm->mux;
1538
1539 if (kcm->rx_disabled)
1540 return;
1541
1542 spin_lock_bh(&mux->rx_lock);
1543
1544 kcm->rx_disabled = 1;
1545
1546 /* If a psock is reserved we'll do cleanup in unreserve */
1547 if (!kcm->rx_psock) {
1548 if (kcm->rx_wait) {
1549 list_del(&kcm->wait_rx_list);
1550 kcm->rx_wait = false;
1551 }
1552
1553 requeue_rx_msgs(mux, &kcm->sk.sk_receive_queue);
1554 }
1555
1556 spin_unlock_bh(&mux->rx_lock);
1557 }
1558
1559 /* kcm sock lock held */
1560 static void kcm_recv_enable(struct kcm_sock *kcm)
1561 {
1562 struct kcm_mux *mux = kcm->mux;
1563
1564 if (!kcm->rx_disabled)
1565 return;
1566
1567 spin_lock_bh(&mux->rx_lock);
1568
1569 kcm->rx_disabled = 0;
1570 kcm_rcv_ready(kcm);
1571
1572 spin_unlock_bh(&mux->rx_lock);
1573 }
1574
1575 static int kcm_setsockopt(struct socket *sock, int level, int optname,
1576 char __user *optval, unsigned int optlen)
1577 {
1578 struct kcm_sock *kcm = kcm_sk(sock->sk);
1579 int val, valbool;
1580 int err = 0;
1581
1582 if (level != SOL_KCM)
1583 return -ENOPROTOOPT;
1584
1585 if (optlen < sizeof(int))
1586 return -EINVAL;
1587
1588 if (get_user(val, (int __user *)optval))
1589 return -EINVAL;
1590
1591 valbool = val ? 1 : 0;
1592
1593 switch (optname) {
1594 case KCM_RECV_DISABLE:
1595 lock_sock(&kcm->sk);
1596 if (valbool)
1597 kcm_recv_disable(kcm);
1598 else
1599 kcm_recv_enable(kcm);
1600 release_sock(&kcm->sk);
1601 break;
1602 default:
1603 err = -ENOPROTOOPT;
1604 }
1605
1606 return err;
1607 }
1608
1609 static int kcm_getsockopt(struct socket *sock, int level, int optname,
1610 char __user *optval, int __user *optlen)
1611 {
1612 struct kcm_sock *kcm = kcm_sk(sock->sk);
1613 int val, len;
1614
1615 if (level != SOL_KCM)
1616 return -ENOPROTOOPT;
1617
1618 if (get_user(len, optlen))
1619 return -EFAULT;
1620
1621 len = min_t(unsigned int, len, sizeof(int));
1622 if (len < 0)
1623 return -EINVAL;
1624
1625 switch (optname) {
1626 case KCM_RECV_DISABLE:
1627 val = kcm->rx_disabled;
1628 break;
1629 default:
1630 return -ENOPROTOOPT;
1631 }
1632
1633 if (put_user(len, optlen))
1634 return -EFAULT;
1635 if (copy_to_user(optval, &val, len))
1636 return -EFAULT;
1637 return 0;
1638 }
1639
1640 static void init_kcm_sock(struct kcm_sock *kcm, struct kcm_mux *mux)
1641 {
1642 struct kcm_sock *tkcm;
1643 struct list_head *head;
1644 int index = 0;
1645
1646 /* For SOCK_SEQPACKET sock type, datagram_poll checks the sk_state, so
1647 * we set sk_state, otherwise epoll_wait always returns right away with
1648 * POLLHUP
1649 */
1650 kcm->sk.sk_state = TCP_ESTABLISHED;
1651
1652 /* Add to mux's kcm sockets list */
1653 kcm->mux = mux;
1654 spin_lock_bh(&mux->lock);
1655
1656 head = &mux->kcm_socks;
1657 list_for_each_entry(tkcm, &mux->kcm_socks, kcm_sock_list) {
1658 if (tkcm->index != index)
1659 break;
1660 head = &tkcm->kcm_sock_list;
1661 index++;
1662 }
1663
1664 list_add(&kcm->kcm_sock_list, head);
1665 kcm->index = index;
1666
1667 mux->kcm_socks_cnt++;
1668 spin_unlock_bh(&mux->lock);
1669
1670 INIT_WORK(&kcm->tx_work, kcm_tx_work);
1671
1672 spin_lock_bh(&mux->rx_lock);
1673 kcm_rcv_ready(kcm);
1674 spin_unlock_bh(&mux->rx_lock);
1675 }
1676
1677 static void kcm_rx_msg_timeout(unsigned long arg)
1678 {
1679 struct kcm_psock *psock = (struct kcm_psock *)arg;
1680
1681 /* Message assembly timed out */
1682 KCM_STATS_INCR(psock->stats.rx_msg_timeouts);
1683 kcm_abort_rx_psock(psock, ETIMEDOUT, NULL);
1684 }
1685
1686 static int kcm_attach(struct socket *sock, struct socket *csock,
1687 struct bpf_prog *prog)
1688 {
1689 struct kcm_sock *kcm = kcm_sk(sock->sk);
1690 struct kcm_mux *mux = kcm->mux;
1691 struct sock *csk;
1692 struct kcm_psock *psock = NULL, *tpsock;
1693 struct list_head *head;
1694 int index = 0;
1695
1696 if (csock->ops->family != PF_INET &&
1697 csock->ops->family != PF_INET6)
1698 return -EINVAL;
1699
1700 csk = csock->sk;
1701 if (!csk)
1702 return -EINVAL;
1703
1704 /* Only support TCP for now */
1705 if (csk->sk_protocol != IPPROTO_TCP)
1706 return -EINVAL;
1707
1708 psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL);
1709 if (!psock)
1710 return -ENOMEM;
1711
1712 psock->mux = mux;
1713 psock->sk = csk;
1714 psock->bpf_prog = prog;
1715
1716 setup_timer(&psock->rx_msg_timer, kcm_rx_msg_timeout,
1717 (unsigned long)psock);
1718
1719 INIT_WORK(&psock->rx_work, psock_rx_work);
1720 INIT_DELAYED_WORK(&psock->rx_delayed_work, psock_rx_delayed_work);
1721
1722 sock_hold(csk);
1723
1724 write_lock_bh(&csk->sk_callback_lock);
1725 psock->save_data_ready = csk->sk_data_ready;
1726 psock->save_write_space = csk->sk_write_space;
1727 psock->save_state_change = csk->sk_state_change;
1728 csk->sk_user_data = psock;
1729 csk->sk_data_ready = psock_tcp_data_ready;
1730 csk->sk_write_space = psock_tcp_write_space;
1731 csk->sk_state_change = psock_tcp_state_change;
1732 write_unlock_bh(&csk->sk_callback_lock);
1733
1734 /* Finished initialization, now add the psock to the MUX. */
1735 spin_lock_bh(&mux->lock);
1736 head = &mux->psocks;
1737 list_for_each_entry(tpsock, &mux->psocks, psock_list) {
1738 if (tpsock->index != index)
1739 break;
1740 head = &tpsock->psock_list;
1741 index++;
1742 }
1743
1744 list_add(&psock->psock_list, head);
1745 psock->index = index;
1746
1747 KCM_STATS_INCR(mux->stats.psock_attach);
1748 mux->psocks_cnt++;
1749 psock_now_avail(psock);
1750 spin_unlock_bh(&mux->lock);
1751
1752 /* Schedule RX work in case there are already bytes queued */
1753 queue_work(kcm_wq, &psock->rx_work);
1754
1755 return 0;
1756 }
1757
1758 static int kcm_attach_ioctl(struct socket *sock, struct kcm_attach *info)
1759 {
1760 struct socket *csock;
1761 struct bpf_prog *prog;
1762 int err;
1763
1764 csock = sockfd_lookup(info->fd, &err);
1765 if (!csock)
1766 return -ENOENT;
1767
1768 prog = bpf_prog_get_type(info->bpf_fd, BPF_PROG_TYPE_SOCKET_FILTER);
1769 if (IS_ERR(prog)) {
1770 err = PTR_ERR(prog);
1771 goto out;
1772 }
1773
1774 err = kcm_attach(sock, csock, prog);
1775 if (err) {
1776 bpf_prog_put(prog);
1777 goto out;
1778 }
1779
1780 /* Keep reference on file also */
1781
1782 return 0;
1783 out:
1784 fput(csock->file);
1785 return err;
1786 }
1787
1788 static void kcm_unattach(struct kcm_psock *psock)
1789 {
1790 struct sock *csk = psock->sk;
1791 struct kcm_mux *mux = psock->mux;
1792
1793 /* Stop getting callbacks from TCP socket. After this there should
1794 * be no way to reserve a kcm for this psock.
1795 */
1796 write_lock_bh(&csk->sk_callback_lock);
1797 csk->sk_user_data = NULL;
1798 csk->sk_data_ready = psock->save_data_ready;
1799 csk->sk_write_space = psock->save_write_space;
1800 csk->sk_state_change = psock->save_state_change;
1801 psock->rx_stopped = 1;
1802
1803 if (WARN_ON(psock->rx_kcm)) {
1804 write_unlock_bh(&csk->sk_callback_lock);
1805 return;
1806 }
1807
1808 spin_lock_bh(&mux->rx_lock);
1809
1810 /* Stop receiver activities. After this point psock should not be
1811 * able to get onto ready list either through callbacks or work.
1812 */
1813 if (psock->ready_rx_msg) {
1814 list_del(&psock->psock_ready_list);
1815 kfree_skb(psock->ready_rx_msg);
1816 psock->ready_rx_msg = NULL;
1817 KCM_STATS_INCR(mux->stats.rx_ready_drops);
1818 }
1819
1820 spin_unlock_bh(&mux->rx_lock);
1821
1822 write_unlock_bh(&csk->sk_callback_lock);
1823
1824 del_timer_sync(&psock->rx_msg_timer);
1825 cancel_work_sync(&psock->rx_work);
1826 cancel_delayed_work_sync(&psock->rx_delayed_work);
1827
1828 bpf_prog_put(psock->bpf_prog);
1829
1830 kfree_skb(psock->rx_skb_head);
1831 psock->rx_skb_head = NULL;
1832
1833 spin_lock_bh(&mux->lock);
1834
1835 aggregate_psock_stats(&psock->stats, &mux->aggregate_psock_stats);
1836
1837 KCM_STATS_INCR(mux->stats.psock_unattach);
1838
1839 if (psock->tx_kcm) {
1840 /* psock was reserved. Just mark it finished and we will clean
1841 * up in the kcm paths, we need kcm lock which can not be
1842 * acquired here.
1843 */
1844 KCM_STATS_INCR(mux->stats.psock_unattach_rsvd);
1845 spin_unlock_bh(&mux->lock);
1846
1847 /* We are unattaching a socket that is reserved. Abort the
1848 * socket since we may be out of sync in sending on it. We need
1849 * to do this without the mux lock.
1850 */
1851 kcm_abort_tx_psock(psock, EPIPE, false);
1852
1853 spin_lock_bh(&mux->lock);
1854 if (!psock->tx_kcm) {
1855 /* psock now unreserved in window mux was unlocked */
1856 goto no_reserved;
1857 }
1858 psock->done = 1;
1859
1860 /* Commit done before queuing work to process it */
1861 smp_mb();
1862
1863 /* Queue tx work to make sure psock->done is handled */
1864 queue_work(kcm_wq, &psock->tx_kcm->tx_work);
1865 spin_unlock_bh(&mux->lock);
1866 } else {
1867 no_reserved:
1868 if (!psock->tx_stopped)
1869 list_del(&psock->psock_avail_list);
1870 list_del(&psock->psock_list);
1871 mux->psocks_cnt--;
1872 spin_unlock_bh(&mux->lock);
1873
1874 sock_put(csk);
1875 fput(csk->sk_socket->file);
1876 kmem_cache_free(kcm_psockp, psock);
1877 }
1878 }
1879
1880 static int kcm_unattach_ioctl(struct socket *sock, struct kcm_unattach *info)
1881 {
1882 struct kcm_sock *kcm = kcm_sk(sock->sk);
1883 struct kcm_mux *mux = kcm->mux;
1884 struct kcm_psock *psock;
1885 struct socket *csock;
1886 struct sock *csk;
1887 int err;
1888
1889 csock = sockfd_lookup(info->fd, &err);
1890 if (!csock)
1891 return -ENOENT;
1892
1893 csk = csock->sk;
1894 if (!csk) {
1895 err = -EINVAL;
1896 goto out;
1897 }
1898
1899 err = -ENOENT;
1900
1901 spin_lock_bh(&mux->lock);
1902
1903 list_for_each_entry(psock, &mux->psocks, psock_list) {
1904 if (psock->sk != csk)
1905 continue;
1906
1907 /* Found the matching psock */
1908
1909 if (psock->unattaching || WARN_ON(psock->done)) {
1910 err = -EALREADY;
1911 break;
1912 }
1913
1914 psock->unattaching = 1;
1915
1916 spin_unlock_bh(&mux->lock);
1917
1918 kcm_unattach(psock);
1919
1920 err = 0;
1921 goto out;
1922 }
1923
1924 spin_unlock_bh(&mux->lock);
1925
1926 out:
1927 fput(csock->file);
1928 return err;
1929 }
1930
1931 static struct proto kcm_proto = {
1932 .name = "KCM",
1933 .owner = THIS_MODULE,
1934 .obj_size = sizeof(struct kcm_sock),
1935 };
1936
1937 /* Clone a kcm socket. */
1938 static int kcm_clone(struct socket *osock, struct kcm_clone *info,
1939 struct socket **newsockp)
1940 {
1941 struct socket *newsock;
1942 struct sock *newsk;
1943 struct file *newfile;
1944 int err, newfd;
1945
1946 err = -ENFILE;
1947 newsock = sock_alloc();
1948 if (!newsock)
1949 goto out;
1950
1951 newsock->type = osock->type;
1952 newsock->ops = osock->ops;
1953
1954 __module_get(newsock->ops->owner);
1955
1956 newfd = get_unused_fd_flags(0);
1957 if (unlikely(newfd < 0)) {
1958 err = newfd;
1959 goto out_fd_fail;
1960 }
1961
1962 newfile = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);
1963 if (unlikely(IS_ERR(newfile))) {
1964 err = PTR_ERR(newfile);
1965 goto out_sock_alloc_fail;
1966 }
1967
1968 newsk = sk_alloc(sock_net(osock->sk), PF_KCM, GFP_KERNEL,
1969 &kcm_proto, true);
1970 if (!newsk) {
1971 err = -ENOMEM;
1972 goto out_sk_alloc_fail;
1973 }
1974
1975 sock_init_data(newsock, newsk);
1976 init_kcm_sock(kcm_sk(newsk), kcm_sk(osock->sk)->mux);
1977
1978 fd_install(newfd, newfile);
1979 *newsockp = newsock;
1980 info->fd = newfd;
1981
1982 return 0;
1983
1984 out_sk_alloc_fail:
1985 fput(newfile);
1986 out_sock_alloc_fail:
1987 put_unused_fd(newfd);
1988 out_fd_fail:
1989 sock_release(newsock);
1990 out:
1991 return err;
1992 }
1993
1994 static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1995 {
1996 int err;
1997
1998 switch (cmd) {
1999 case SIOCKCMATTACH: {
2000 struct kcm_attach info;
2001
2002 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
2003 err = -EFAULT;
2004
2005 err = kcm_attach_ioctl(sock, &info);
2006
2007 break;
2008 }
2009 case SIOCKCMUNATTACH: {
2010 struct kcm_unattach info;
2011
2012 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
2013 err = -EFAULT;
2014
2015 err = kcm_unattach_ioctl(sock, &info);
2016
2017 break;
2018 }
2019 case SIOCKCMCLONE: {
2020 struct kcm_clone info;
2021 struct socket *newsock = NULL;
2022
2023 if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
2024 err = -EFAULT;
2025
2026 err = kcm_clone(sock, &info, &newsock);
2027
2028 if (!err) {
2029 if (copy_to_user((void __user *)arg, &info,
2030 sizeof(info))) {
2031 err = -EFAULT;
2032 sock_release(newsock);
2033 }
2034 }
2035
2036 break;
2037 }
2038 default:
2039 err = -ENOIOCTLCMD;
2040 break;
2041 }
2042
2043 return err;
2044 }
2045
2046 static void free_mux(struct rcu_head *rcu)
2047 {
2048 struct kcm_mux *mux = container_of(rcu,
2049 struct kcm_mux, rcu);
2050
2051 kmem_cache_free(kcm_muxp, mux);
2052 }
2053
2054 static void release_mux(struct kcm_mux *mux)
2055 {
2056 struct kcm_net *knet = mux->knet;
2057 struct kcm_psock *psock, *tmp_psock;
2058
2059 /* Release psocks */
2060 list_for_each_entry_safe(psock, tmp_psock,
2061 &mux->psocks, psock_list) {
2062 if (!WARN_ON(psock->unattaching))
2063 kcm_unattach(psock);
2064 }
2065
2066 if (WARN_ON(mux->psocks_cnt))
2067 return;
2068
2069 __skb_queue_purge(&mux->rx_hold_queue);
2070
2071 mutex_lock(&knet->mutex);
2072 aggregate_mux_stats(&mux->stats, &knet->aggregate_mux_stats);
2073 aggregate_psock_stats(&mux->aggregate_psock_stats,
2074 &knet->aggregate_psock_stats);
2075 list_del_rcu(&mux->kcm_mux_list);
2076 knet->count--;
2077 mutex_unlock(&knet->mutex);
2078
2079 call_rcu(&mux->rcu, free_mux);
2080 }
2081
2082 static void kcm_done(struct kcm_sock *kcm)
2083 {
2084 struct kcm_mux *mux = kcm->mux;
2085 struct sock *sk = &kcm->sk;
2086 int socks_cnt;
2087
2088 spin_lock_bh(&mux->rx_lock);
2089 if (kcm->rx_psock) {
2090 /* Cleanup in unreserve_rx_kcm */
2091 WARN_ON(kcm->done);
2092 kcm->rx_disabled = 1;
2093 kcm->done = 1;
2094 spin_unlock_bh(&mux->rx_lock);
2095 return;
2096 }
2097
2098 if (kcm->rx_wait) {
2099 list_del(&kcm->wait_rx_list);
2100 kcm->rx_wait = false;
2101 }
2102 /* Move any pending receive messages to other kcm sockets */
2103 requeue_rx_msgs(mux, &sk->sk_receive_queue);
2104
2105 spin_unlock_bh(&mux->rx_lock);
2106
2107 if (WARN_ON(sk_rmem_alloc_get(sk)))
2108 return;
2109
2110 /* Detach from MUX */
2111 spin_lock_bh(&mux->lock);
2112
2113 list_del(&kcm->kcm_sock_list);
2114 mux->kcm_socks_cnt--;
2115 socks_cnt = mux->kcm_socks_cnt;
2116
2117 spin_unlock_bh(&mux->lock);
2118
2119 if (!socks_cnt) {
2120 /* We are done with the mux now. */
2121 release_mux(mux);
2122 }
2123
2124 WARN_ON(kcm->rx_wait);
2125
2126 sock_put(&kcm->sk);
2127 }
2128
2129 /* Called by kcm_release to close a KCM socket.
2130 * If this is the last KCM socket on the MUX, destroy the MUX.
2131 */
2132 static int kcm_release(struct socket *sock)
2133 {
2134 struct sock *sk = sock->sk;
2135 struct kcm_sock *kcm;
2136 struct kcm_mux *mux;
2137 struct kcm_psock *psock;
2138
2139 if (!sk)
2140 return 0;
2141
2142 kcm = kcm_sk(sk);
2143 mux = kcm->mux;
2144
2145 sock_orphan(sk);
2146 kfree_skb(kcm->seq_skb);
2147
2148 lock_sock(sk);
2149 /* Purge queue under lock to avoid race condition with tx_work trying
2150 * to act when queue is nonempty. If tx_work runs after this point
2151 * it will just return.
2152 */
2153 __skb_queue_purge(&sk->sk_write_queue);
2154 release_sock(sk);
2155
2156 spin_lock_bh(&mux->lock);
2157 if (kcm->tx_wait) {
2158 /* Take of tx_wait list, after this point there should be no way
2159 * that a psock will be assigned to this kcm.
2160 */
2161 list_del(&kcm->wait_psock_list);
2162 kcm->tx_wait = false;
2163 }
2164 spin_unlock_bh(&mux->lock);
2165
2166 /* Cancel work. After this point there should be no outside references
2167 * to the kcm socket.
2168 */
2169 cancel_work_sync(&kcm->tx_work);
2170
2171 lock_sock(sk);
2172 psock = kcm->tx_psock;
2173 if (psock) {
2174 /* A psock was reserved, so we need to kill it since it
2175 * may already have some bytes queued from a message. We
2176 * need to do this after removing kcm from tx_wait list.
2177 */
2178 kcm_abort_tx_psock(psock, EPIPE, false);
2179 unreserve_psock(kcm);
2180 }
2181 release_sock(sk);
2182
2183 WARN_ON(kcm->tx_wait);
2184 WARN_ON(kcm->tx_psock);
2185
2186 sock->sk = NULL;
2187
2188 kcm_done(kcm);
2189
2190 return 0;
2191 }
2192
2193 static const struct proto_ops kcm_dgram_ops = {
2194 .family = PF_KCM,
2195 .owner = THIS_MODULE,
2196 .release = kcm_release,
2197 .bind = sock_no_bind,
2198 .connect = sock_no_connect,
2199 .socketpair = sock_no_socketpair,
2200 .accept = sock_no_accept,
2201 .getname = sock_no_getname,
2202 .poll = datagram_poll,
2203 .ioctl = kcm_ioctl,
2204 .listen = sock_no_listen,
2205 .shutdown = sock_no_shutdown,
2206 .setsockopt = kcm_setsockopt,
2207 .getsockopt = kcm_getsockopt,
2208 .sendmsg = kcm_sendmsg,
2209 .recvmsg = kcm_recvmsg,
2210 .mmap = sock_no_mmap,
2211 .sendpage = kcm_sendpage,
2212 };
2213
2214 static const struct proto_ops kcm_seqpacket_ops = {
2215 .family = PF_KCM,
2216 .owner = THIS_MODULE,
2217 .release = kcm_release,
2218 .bind = sock_no_bind,
2219 .connect = sock_no_connect,
2220 .socketpair = sock_no_socketpair,
2221 .accept = sock_no_accept,
2222 .getname = sock_no_getname,
2223 .poll = datagram_poll,
2224 .ioctl = kcm_ioctl,
2225 .listen = sock_no_listen,
2226 .shutdown = sock_no_shutdown,
2227 .setsockopt = kcm_setsockopt,
2228 .getsockopt = kcm_getsockopt,
2229 .sendmsg = kcm_sendmsg,
2230 .recvmsg = kcm_recvmsg,
2231 .mmap = sock_no_mmap,
2232 .sendpage = kcm_sendpage,
2233 .splice_read = kcm_splice_read,
2234 };
2235
2236 /* Create proto operation for kcm sockets */
2237 static int kcm_create(struct net *net, struct socket *sock,
2238 int protocol, int kern)
2239 {
2240 struct kcm_net *knet = net_generic(net, kcm_net_id);
2241 struct sock *sk;
2242 struct kcm_mux *mux;
2243
2244 switch (sock->type) {
2245 case SOCK_DGRAM:
2246 sock->ops = &kcm_dgram_ops;
2247 break;
2248 case SOCK_SEQPACKET:
2249 sock->ops = &kcm_seqpacket_ops;
2250 break;
2251 default:
2252 return -ESOCKTNOSUPPORT;
2253 }
2254
2255 if (protocol != KCMPROTO_CONNECTED)
2256 return -EPROTONOSUPPORT;
2257
2258 sk = sk_alloc(net, PF_KCM, GFP_KERNEL, &kcm_proto, kern);
2259 if (!sk)
2260 return -ENOMEM;
2261
2262 /* Allocate a kcm mux, shared between KCM sockets */
2263 mux = kmem_cache_zalloc(kcm_muxp, GFP_KERNEL);
2264 if (!mux) {
2265 sk_free(sk);
2266 return -ENOMEM;
2267 }
2268
2269 spin_lock_init(&mux->lock);
2270 spin_lock_init(&mux->rx_lock);
2271 INIT_LIST_HEAD(&mux->kcm_socks);
2272 INIT_LIST_HEAD(&mux->kcm_rx_waiters);
2273 INIT_LIST_HEAD(&mux->kcm_tx_waiters);
2274
2275 INIT_LIST_HEAD(&mux->psocks);
2276 INIT_LIST_HEAD(&mux->psocks_ready);
2277 INIT_LIST_HEAD(&mux->psocks_avail);
2278
2279 mux->knet = knet;
2280
2281 /* Add new MUX to list */
2282 mutex_lock(&knet->mutex);
2283 list_add_rcu(&mux->kcm_mux_list, &knet->mux_list);
2284 knet->count++;
2285 mutex_unlock(&knet->mutex);
2286
2287 skb_queue_head_init(&mux->rx_hold_queue);
2288
2289 /* Init KCM socket */
2290 sock_init_data(sock, sk);
2291 init_kcm_sock(kcm_sk(sk), mux);
2292
2293 return 0;
2294 }
2295
2296 static struct net_proto_family kcm_family_ops = {
2297 .family = PF_KCM,
2298 .create = kcm_create,
2299 .owner = THIS_MODULE,
2300 };
2301
2302 static __net_init int kcm_init_net(struct net *net)
2303 {
2304 struct kcm_net *knet = net_generic(net, kcm_net_id);
2305
2306 INIT_LIST_HEAD_RCU(&knet->mux_list);
2307 mutex_init(&knet->mutex);
2308
2309 return 0;
2310 }
2311
2312 static __net_exit void kcm_exit_net(struct net *net)
2313 {
2314 struct kcm_net *knet = net_generic(net, kcm_net_id);
2315
2316 /* All KCM sockets should be closed at this point, which should mean
2317 * that all multiplexors and psocks have been destroyed.
2318 */
2319 WARN_ON(!list_empty(&knet->mux_list));
2320 }
2321
2322 static struct pernet_operations kcm_net_ops = {
2323 .init = kcm_init_net,
2324 .exit = kcm_exit_net,
2325 .id = &kcm_net_id,
2326 .size = sizeof(struct kcm_net),
2327 };
2328
2329 static int __init kcm_init(void)
2330 {
2331 int err = -ENOMEM;
2332
2333 kcm_muxp = kmem_cache_create("kcm_mux_cache",
2334 sizeof(struct kcm_mux), 0,
2335 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
2336 if (!kcm_muxp)
2337 goto fail;
2338
2339 kcm_psockp = kmem_cache_create("kcm_psock_cache",
2340 sizeof(struct kcm_psock), 0,
2341 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
2342 if (!kcm_psockp)
2343 goto fail;
2344
2345 kcm_wq = create_singlethread_workqueue("kkcmd");
2346 if (!kcm_wq)
2347 goto fail;
2348
2349 err = proto_register(&kcm_proto, 1);
2350 if (err)
2351 goto fail;
2352
2353 err = sock_register(&kcm_family_ops);
2354 if (err)
2355 goto sock_register_fail;
2356
2357 err = register_pernet_device(&kcm_net_ops);
2358 if (err)
2359 goto net_ops_fail;
2360
2361 err = kcm_proc_init();
2362 if (err)
2363 goto proc_init_fail;
2364
2365 return 0;
2366
2367 proc_init_fail:
2368 unregister_pernet_device(&kcm_net_ops);
2369
2370 net_ops_fail:
2371 sock_unregister(PF_KCM);
2372
2373 sock_register_fail:
2374 proto_unregister(&kcm_proto);
2375
2376 fail:
2377 kmem_cache_destroy(kcm_muxp);
2378 kmem_cache_destroy(kcm_psockp);
2379
2380 if (kcm_wq)
2381 destroy_workqueue(kcm_wq);
2382
2383 return err;
2384 }
2385
2386 static void __exit kcm_exit(void)
2387 {
2388 kcm_proc_exit();
2389 unregister_pernet_device(&kcm_net_ops);
2390 sock_unregister(PF_KCM);
2391 proto_unregister(&kcm_proto);
2392 destroy_workqueue(kcm_wq);
2393
2394 kmem_cache_destroy(kcm_muxp);
2395 kmem_cache_destroy(kcm_psockp);
2396 }
2397
2398 module_init(kcm_init);
2399 module_exit(kcm_exit);
2400
2401 MODULE_LICENSE("GPL");
2402 MODULE_ALIAS_NETPROTO(PF_KCM);
2403
Linux kernel - Deliverables
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