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