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