1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* RxRPC recvmsg() implementation
3 *
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/net.h>
11 #include <linux/skbuff.h>
12 #include <linux/export.h>
13 #include <linux/sched/signal.h>
14
15 #include <net/sock.h>
16 #include <net/af_rxrpc.h>
17 #include "ar-internal.h"
18
19 /*
20 * Post a call for attention by the socket or kernel service. Further
21 * notifications are suppressed by putting recvmsg_link on a dummy queue.
22 */
rxrpc_notify_socket(struct rxrpc_call * call)23 void rxrpc_notify_socket(struct rxrpc_call *call)
24 {
25 struct rxrpc_sock *rx;
26 struct sock *sk;
27
28 _enter("%d", call->debug_id);
29
30 if (!list_empty(&call->recvmsg_link))
31 return;
32
33 rcu_read_lock();
34
35 rx = rcu_dereference(call->socket);
36 sk = &rx->sk;
37 if (rx && sk->sk_state < RXRPC_CLOSE) {
38 if (call->notify_rx) {
39 spin_lock_bh(&call->notify_lock);
40 call->notify_rx(sk, call, call->user_call_ID);
41 spin_unlock_bh(&call->notify_lock);
42 } else {
43 write_lock_bh(&rx->recvmsg_lock);
44 if (list_empty(&call->recvmsg_link)) {
45 rxrpc_get_call(call, rxrpc_call_got);
46 list_add_tail(&call->recvmsg_link, &rx->recvmsg_q);
47 }
48 write_unlock_bh(&rx->recvmsg_lock);
49
50 if (!sock_flag(sk, SOCK_DEAD)) {
51 _debug("call %ps", sk->sk_data_ready);
52 sk->sk_data_ready(sk);
53 }
54 }
55 }
56
57 rcu_read_unlock();
58 _leave("");
59 }
60
61 /*
62 * Pass a call terminating message to userspace.
63 */
rxrpc_recvmsg_term(struct rxrpc_call * call,struct msghdr * msg)64 static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg)
65 {
66 u32 tmp = 0;
67 int ret;
68
69 switch (call->completion) {
70 case RXRPC_CALL_SUCCEEDED:
71 ret = 0;
72 if (rxrpc_is_service_call(call))
73 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &tmp);
74 break;
75 case RXRPC_CALL_REMOTELY_ABORTED:
76 tmp = call->abort_code;
77 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
78 break;
79 case RXRPC_CALL_LOCALLY_ABORTED:
80 tmp = call->abort_code;
81 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
82 break;
83 case RXRPC_CALL_NETWORK_ERROR:
84 tmp = -call->error;
85 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &tmp);
86 break;
87 case RXRPC_CALL_LOCAL_ERROR:
88 tmp = -call->error;
89 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4, &tmp);
90 break;
91 default:
92 pr_err("Invalid terminal call state %u\n", call->state);
93 BUG();
94 break;
95 }
96
97 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_terminal, call->rx_hard_ack,
98 call->rx_pkt_offset, call->rx_pkt_len, ret);
99 return ret;
100 }
101
102 /*
103 * Pass back notification of a new call. The call is added to the
104 * to-be-accepted list. This means that the next call to be accepted might not
105 * be the last call seen awaiting acceptance, but unless we leave this on the
106 * front of the queue and block all other messages until someone gives us a
107 * user_ID for it, there's not a lot we can do.
108 */
rxrpc_recvmsg_new_call(struct rxrpc_sock * rx,struct rxrpc_call * call,struct msghdr * msg,int flags)109 static int rxrpc_recvmsg_new_call(struct rxrpc_sock *rx,
110 struct rxrpc_call *call,
111 struct msghdr *msg, int flags)
112 {
113 int tmp = 0, ret;
114
115 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &tmp);
116
117 if (ret == 0 && !(flags & MSG_PEEK)) {
118 _debug("to be accepted");
119 write_lock_bh(&rx->recvmsg_lock);
120 list_del_init(&call->recvmsg_link);
121 write_unlock_bh(&rx->recvmsg_lock);
122
123 rxrpc_get_call(call, rxrpc_call_got);
124 write_lock(&rx->call_lock);
125 list_add_tail(&call->accept_link, &rx->to_be_accepted);
126 write_unlock(&rx->call_lock);
127 }
128
129 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_to_be_accepted, 1, 0, 0, ret);
130 return ret;
131 }
132
133 /*
134 * End the packet reception phase.
135 */
rxrpc_end_rx_phase(struct rxrpc_call * call,rxrpc_serial_t serial)136 static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial)
137 {
138 _enter("%d,%s", call->debug_id, rxrpc_call_states[call->state]);
139
140 trace_rxrpc_receive(call, rxrpc_receive_end, 0, call->rx_top);
141 ASSERTCMP(call->rx_hard_ack, ==, call->rx_top);
142
143 if (call->state == RXRPC_CALL_CLIENT_RECV_REPLY) {
144 rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, serial, false, true,
145 rxrpc_propose_ack_terminal_ack);
146 //rxrpc_send_ack_packet(call, false, NULL);
147 }
148
149 write_lock_bh(&call->state_lock);
150
151 switch (call->state) {
152 case RXRPC_CALL_CLIENT_RECV_REPLY:
153 __rxrpc_call_completed(call);
154 write_unlock_bh(&call->state_lock);
155 break;
156
157 case RXRPC_CALL_SERVER_RECV_REQUEST:
158 call->tx_phase = true;
159 call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
160 call->expect_req_by = jiffies + MAX_JIFFY_OFFSET;
161 write_unlock_bh(&call->state_lock);
162 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, serial, false, true,
163 rxrpc_propose_ack_processing_op);
164 break;
165 default:
166 write_unlock_bh(&call->state_lock);
167 break;
168 }
169 }
170
171 /*
172 * Discard a packet we've used up and advance the Rx window by one.
173 */
rxrpc_rotate_rx_window(struct rxrpc_call * call)174 static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
175 {
176 struct rxrpc_skb_priv *sp;
177 struct sk_buff *skb;
178 rxrpc_serial_t serial;
179 rxrpc_seq_t hard_ack, top;
180 bool last = false;
181 u8 subpacket;
182 int ix;
183
184 _enter("%d", call->debug_id);
185
186 hard_ack = call->rx_hard_ack;
187 top = smp_load_acquire(&call->rx_top);
188 ASSERT(before(hard_ack, top));
189
190 hard_ack++;
191 ix = hard_ack & RXRPC_RXTX_BUFF_MASK;
192 skb = call->rxtx_buffer[ix];
193 rxrpc_see_skb(skb, rxrpc_skb_rotated);
194 sp = rxrpc_skb(skb);
195
196 subpacket = call->rxtx_annotations[ix] & RXRPC_RX_ANNO_SUBPACKET;
197 serial = sp->hdr.serial + subpacket;
198
199 if (subpacket == sp->nr_subpackets - 1 &&
200 sp->rx_flags & RXRPC_SKB_INCL_LAST)
201 last = true;
202
203 call->rxtx_buffer[ix] = NULL;
204 call->rxtx_annotations[ix] = 0;
205 /* Barrier against rxrpc_input_data(). */
206 smp_store_release(&call->rx_hard_ack, hard_ack);
207
208 rxrpc_free_skb(skb, rxrpc_skb_freed);
209
210 trace_rxrpc_receive(call, rxrpc_receive_rotate, serial, hard_ack);
211 if (last) {
212 rxrpc_end_rx_phase(call, serial);
213 } else {
214 /* Check to see if there's an ACK that needs sending. */
215 if (atomic_inc_return(&call->ackr_nr_consumed) > 2)
216 rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, serial,
217 true, false,
218 rxrpc_propose_ack_rotate_rx);
219 if (call->ackr_reason && call->ackr_reason != RXRPC_ACK_DELAY)
220 rxrpc_send_ack_packet(call, false, NULL);
221 }
222 }
223
224 /*
225 * Decrypt and verify a (sub)packet. The packet's length may be changed due to
226 * padding, but if this is the case, the packet length will be resident in the
227 * socket buffer. Note that we can't modify the master skb info as the skb may
228 * be the home to multiple subpackets.
229 */
rxrpc_verify_packet(struct rxrpc_call * call,struct sk_buff * skb,u8 annotation,unsigned int offset,unsigned int len)230 static int rxrpc_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
231 u8 annotation,
232 unsigned int offset, unsigned int len)
233 {
234 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
235 rxrpc_seq_t seq = sp->hdr.seq;
236 u16 cksum = sp->hdr.cksum;
237 u8 subpacket = annotation & RXRPC_RX_ANNO_SUBPACKET;
238
239 _enter("");
240
241 /* For all but the head jumbo subpacket, the security checksum is in a
242 * jumbo header immediately prior to the data.
243 */
244 if (subpacket > 0) {
245 __be16 tmp;
246 if (skb_copy_bits(skb, offset - 2, &tmp, 2) < 0)
247 BUG();
248 cksum = ntohs(tmp);
249 seq += subpacket;
250 }
251
252 return call->security->verify_packet(call, skb, offset, len,
253 seq, cksum);
254 }
255
256 /*
257 * Locate the data within a packet. This is complicated by:
258 *
259 * (1) An skb may contain a jumbo packet - so we have to find the appropriate
260 * subpacket.
261 *
262 * (2) The (sub)packets may be encrypted and, if so, the encrypted portion
263 * contains an extra header which includes the true length of the data,
264 * excluding any encrypted padding.
265 */
rxrpc_locate_data(struct rxrpc_call * call,struct sk_buff * skb,u8 * _annotation,unsigned int * _offset,unsigned int * _len,bool * _last)266 static int rxrpc_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
267 u8 *_annotation,
268 unsigned int *_offset, unsigned int *_len,
269 bool *_last)
270 {
271 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
272 unsigned int offset = sizeof(struct rxrpc_wire_header);
273 unsigned int len;
274 bool last = false;
275 int ret;
276 u8 annotation = *_annotation;
277 u8 subpacket = annotation & RXRPC_RX_ANNO_SUBPACKET;
278
279 /* Locate the subpacket */
280 offset += subpacket * RXRPC_JUMBO_SUBPKTLEN;
281 len = skb->len - offset;
282 if (subpacket < sp->nr_subpackets - 1)
283 len = RXRPC_JUMBO_DATALEN;
284 else if (sp->rx_flags & RXRPC_SKB_INCL_LAST)
285 last = true;
286
287 if (!(annotation & RXRPC_RX_ANNO_VERIFIED)) {
288 ret = rxrpc_verify_packet(call, skb, annotation, offset, len);
289 if (ret < 0)
290 return ret;
291 *_annotation |= RXRPC_RX_ANNO_VERIFIED;
292 }
293
294 *_offset = offset;
295 *_len = len;
296 *_last = last;
297 call->security->locate_data(call, skb, _offset, _len);
298 return 0;
299 }
300
301 /*
302 * Deliver messages to a call. This keeps processing packets until the buffer
303 * is filled and we find either more DATA (returns 0) or the end of the DATA
304 * (returns 1). If more packets are required, it returns -EAGAIN.
305 */
rxrpc_recvmsg_data(struct socket * sock,struct rxrpc_call * call,struct msghdr * msg,struct iov_iter * iter,size_t len,int flags,size_t * _offset)306 static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
307 struct msghdr *msg, struct iov_iter *iter,
308 size_t len, int flags, size_t *_offset)
309 {
310 struct rxrpc_skb_priv *sp;
311 struct sk_buff *skb;
312 rxrpc_serial_t serial;
313 rxrpc_seq_t hard_ack, top, seq;
314 size_t remain;
315 bool rx_pkt_last;
316 unsigned int rx_pkt_offset, rx_pkt_len;
317 int ix, copy, ret = -EAGAIN, ret2;
318
319 if (test_and_clear_bit(RXRPC_CALL_RX_UNDERRUN, &call->flags) &&
320 call->ackr_reason)
321 rxrpc_send_ack_packet(call, false, NULL);
322
323 rx_pkt_offset = call->rx_pkt_offset;
324 rx_pkt_len = call->rx_pkt_len;
325 rx_pkt_last = call->rx_pkt_last;
326
327 if (call->state >= RXRPC_CALL_SERVER_ACK_REQUEST) {
328 seq = call->rx_hard_ack;
329 ret = 1;
330 goto done;
331 }
332
333 /* Barriers against rxrpc_input_data(). */
334 hard_ack = call->rx_hard_ack;
335 seq = hard_ack + 1;
336
337 while (top = smp_load_acquire(&call->rx_top),
338 before_eq(seq, top)
339 ) {
340 ix = seq & RXRPC_RXTX_BUFF_MASK;
341 skb = call->rxtx_buffer[ix];
342 if (!skb) {
343 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_hole, seq,
344 rx_pkt_offset, rx_pkt_len, 0);
345 break;
346 }
347 smp_rmb();
348 rxrpc_see_skb(skb, rxrpc_skb_seen);
349 sp = rxrpc_skb(skb);
350
351 if (!(flags & MSG_PEEK)) {
352 serial = sp->hdr.serial;
353 serial += call->rxtx_annotations[ix] & RXRPC_RX_ANNO_SUBPACKET;
354 trace_rxrpc_receive(call, rxrpc_receive_front,
355 serial, seq);
356 }
357
358 if (msg)
359 sock_recv_timestamp(msg, sock->sk, skb);
360
361 if (rx_pkt_offset == 0) {
362 ret2 = rxrpc_locate_data(call, skb,
363 &call->rxtx_annotations[ix],
364 &rx_pkt_offset, &rx_pkt_len,
365 &rx_pkt_last);
366 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_next, seq,
367 rx_pkt_offset, rx_pkt_len, ret2);
368 if (ret2 < 0) {
369 ret = ret2;
370 goto out;
371 }
372 } else {
373 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_cont, seq,
374 rx_pkt_offset, rx_pkt_len, 0);
375 }
376
377 /* We have to handle short, empty and used-up DATA packets. */
378 remain = len - *_offset;
379 copy = rx_pkt_len;
380 if (copy > remain)
381 copy = remain;
382 if (copy > 0) {
383 ret2 = skb_copy_datagram_iter(skb, rx_pkt_offset, iter,
384 copy);
385 if (ret2 < 0) {
386 ret = ret2;
387 goto out;
388 }
389
390 /* handle piecemeal consumption of data packets */
391 rx_pkt_offset += copy;
392 rx_pkt_len -= copy;
393 *_offset += copy;
394 }
395
396 if (rx_pkt_len > 0) {
397 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_full, seq,
398 rx_pkt_offset, rx_pkt_len, 0);
399 ASSERTCMP(*_offset, ==, len);
400 ret = 0;
401 break;
402 }
403
404 /* The whole packet has been transferred. */
405 if (!(flags & MSG_PEEK))
406 rxrpc_rotate_rx_window(call);
407 rx_pkt_offset = 0;
408 rx_pkt_len = 0;
409
410 if (rx_pkt_last) {
411 ASSERTCMP(seq, ==, READ_ONCE(call->rx_top));
412 ret = 1;
413 goto out;
414 }
415
416 seq++;
417 }
418
419 out:
420 if (!(flags & MSG_PEEK)) {
421 call->rx_pkt_offset = rx_pkt_offset;
422 call->rx_pkt_len = rx_pkt_len;
423 call->rx_pkt_last = rx_pkt_last;
424 }
425 done:
426 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_data_return, seq,
427 rx_pkt_offset, rx_pkt_len, ret);
428 if (ret == -EAGAIN)
429 set_bit(RXRPC_CALL_RX_UNDERRUN, &call->flags);
430 return ret;
431 }
432
433 /*
434 * Receive a message from an RxRPC socket
435 * - we need to be careful about two or more threads calling recvmsg
436 * simultaneously
437 */
rxrpc_recvmsg(struct socket * sock,struct msghdr * msg,size_t len,int flags)438 int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
439 int flags)
440 {
441 struct rxrpc_call *call;
442 struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
443 struct list_head *l;
444 size_t copied = 0;
445 long timeo;
446 int ret;
447
448 DEFINE_WAIT(wait);
449
450 trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_enter, 0, 0, 0, 0);
451
452 if (flags & (MSG_OOB | MSG_TRUNC))
453 return -EOPNOTSUPP;
454
455 timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
456
457 try_again:
458 lock_sock(&rx->sk);
459
460 /* Return immediately if a client socket has no outstanding calls */
461 if (RB_EMPTY_ROOT(&rx->calls) &&
462 list_empty(&rx->recvmsg_q) &&
463 rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
464 release_sock(&rx->sk);
465 return -EAGAIN;
466 }
467
468 if (list_empty(&rx->recvmsg_q)) {
469 ret = -EWOULDBLOCK;
470 if (timeo == 0) {
471 call = NULL;
472 goto error_no_call;
473 }
474
475 release_sock(&rx->sk);
476
477 /* Wait for something to happen */
478 prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
479 TASK_INTERRUPTIBLE);
480 ret = sock_error(&rx->sk);
481 if (ret)
482 goto wait_error;
483
484 if (list_empty(&rx->recvmsg_q)) {
485 if (signal_pending(current))
486 goto wait_interrupted;
487 trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_wait,
488 0, 0, 0, 0);
489 timeo = schedule_timeout(timeo);
490 }
491 finish_wait(sk_sleep(&rx->sk), &wait);
492 goto try_again;
493 }
494
495 /* Find the next call and dequeue it if we're not just peeking. If we
496 * do dequeue it, that comes with a ref that we will need to release.
497 */
498 write_lock_bh(&rx->recvmsg_lock);
499 l = rx->recvmsg_q.next;
500 call = list_entry(l, struct rxrpc_call, recvmsg_link);
501 if (!(flags & MSG_PEEK))
502 list_del_init(&call->recvmsg_link);
503 else
504 rxrpc_get_call(call, rxrpc_call_got);
505 write_unlock_bh(&rx->recvmsg_lock);
506
507 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_dequeue, 0, 0, 0, 0);
508
509 /* We're going to drop the socket lock, so we need to lock the call
510 * against interference by sendmsg.
511 */
512 if (!mutex_trylock(&call->user_mutex)) {
513 ret = -EWOULDBLOCK;
514 if (flags & MSG_DONTWAIT)
515 goto error_requeue_call;
516 ret = -ERESTARTSYS;
517 if (mutex_lock_interruptible(&call->user_mutex) < 0)
518 goto error_requeue_call;
519 }
520
521 release_sock(&rx->sk);
522
523 if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
524 BUG();
525
526 if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
527 if (flags & MSG_CMSG_COMPAT) {
528 unsigned int id32 = call->user_call_ID;
529
530 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
531 sizeof(unsigned int), &id32);
532 } else {
533 unsigned long idl = call->user_call_ID;
534
535 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
536 sizeof(unsigned long), &idl);
537 }
538 if (ret < 0)
539 goto error_unlock_call;
540 }
541
542 if (msg->msg_name && call->peer) {
543 struct sockaddr_rxrpc *srx = msg->msg_name;
544 size_t len = sizeof(call->peer->srx);
545
546 memcpy(msg->msg_name, &call->peer->srx, len);
547 srx->srx_service = call->service_id;
548 msg->msg_namelen = len;
549 }
550
551 switch (READ_ONCE(call->state)) {
552 case RXRPC_CALL_SERVER_ACCEPTING:
553 ret = rxrpc_recvmsg_new_call(rx, call, msg, flags);
554 break;
555 case RXRPC_CALL_CLIENT_RECV_REPLY:
556 case RXRPC_CALL_SERVER_RECV_REQUEST:
557 case RXRPC_CALL_SERVER_ACK_REQUEST:
558 ret = rxrpc_recvmsg_data(sock, call, msg, &msg->msg_iter, len,
559 flags, &copied);
560 if (ret == -EAGAIN)
561 ret = 0;
562
563 if (after(call->rx_top, call->rx_hard_ack) &&
564 call->rxtx_buffer[(call->rx_hard_ack + 1) & RXRPC_RXTX_BUFF_MASK])
565 rxrpc_notify_socket(call);
566 break;
567 default:
568 ret = 0;
569 break;
570 }
571
572 if (ret < 0)
573 goto error_unlock_call;
574
575 if (call->state == RXRPC_CALL_COMPLETE) {
576 ret = rxrpc_recvmsg_term(call, msg);
577 if (ret < 0)
578 goto error_unlock_call;
579 if (!(flags & MSG_PEEK))
580 rxrpc_release_call(rx, call);
581 msg->msg_flags |= MSG_EOR;
582 ret = 1;
583 }
584
585 if (ret == 0)
586 msg->msg_flags |= MSG_MORE;
587 else
588 msg->msg_flags &= ~MSG_MORE;
589 ret = copied;
590
591 error_unlock_call:
592 mutex_unlock(&call->user_mutex);
593 rxrpc_put_call(call, rxrpc_call_put);
594 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret);
595 return ret;
596
597 error_requeue_call:
598 if (!(flags & MSG_PEEK)) {
599 write_lock_bh(&rx->recvmsg_lock);
600 list_add(&call->recvmsg_link, &rx->recvmsg_q);
601 write_unlock_bh(&rx->recvmsg_lock);
602 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_requeue, 0, 0, 0, 0);
603 } else {
604 rxrpc_put_call(call, rxrpc_call_put);
605 }
606 error_no_call:
607 release_sock(&rx->sk);
608 error_trace:
609 trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret);
610 return ret;
611
612 wait_interrupted:
613 ret = sock_intr_errno(timeo);
614 wait_error:
615 finish_wait(sk_sleep(&rx->sk), &wait);
616 call = NULL;
617 goto error_trace;
618 }
619
620 /**
621 * rxrpc_kernel_recv_data - Allow a kernel service to receive data/info
622 * @sock: The socket that the call exists on
623 * @call: The call to send data through
624 * @iter: The buffer to receive into
625 * @want_more: True if more data is expected to be read
626 * @_abort: Where the abort code is stored if -ECONNABORTED is returned
627 * @_service: Where to store the actual service ID (may be upgraded)
628 *
629 * Allow a kernel service to receive data and pick up information about the
630 * state of a call. Returns 0 if got what was asked for and there's more
631 * available, 1 if we got what was asked for and we're at the end of the data
632 * and -EAGAIN if we need more data.
633 *
634 * Note that we may return -EAGAIN to drain empty packets at the end of the
635 * data, even if we've already copied over the requested data.
636 *
637 * *_abort should also be initialised to 0.
638 */
rxrpc_kernel_recv_data(struct socket * sock,struct rxrpc_call * call,struct iov_iter * iter,bool want_more,u32 * _abort,u16 * _service)639 int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
640 struct iov_iter *iter,
641 bool want_more, u32 *_abort, u16 *_service)
642 {
643 size_t offset = 0;
644 int ret;
645
646 _enter("{%d,%s},%zu,%d",
647 call->debug_id, rxrpc_call_states[call->state],
648 iov_iter_count(iter), want_more);
649
650 ASSERTCMP(call->state, !=, RXRPC_CALL_SERVER_ACCEPTING);
651
652 mutex_lock(&call->user_mutex);
653
654 switch (READ_ONCE(call->state)) {
655 case RXRPC_CALL_CLIENT_RECV_REPLY:
656 case RXRPC_CALL_SERVER_RECV_REQUEST:
657 case RXRPC_CALL_SERVER_ACK_REQUEST:
658 ret = rxrpc_recvmsg_data(sock, call, NULL, iter,
659 iov_iter_count(iter), 0,
660 &offset);
661 if (ret < 0)
662 goto out;
663
664 /* We can only reach here with a partially full buffer if we
665 * have reached the end of the data. We must otherwise have a
666 * full buffer or have been given -EAGAIN.
667 */
668 if (ret == 1) {
669 if (iov_iter_count(iter) > 0)
670 goto short_data;
671 if (!want_more)
672 goto read_phase_complete;
673 ret = 0;
674 goto out;
675 }
676
677 if (!want_more)
678 goto excess_data;
679 goto out;
680
681 case RXRPC_CALL_COMPLETE:
682 goto call_complete;
683
684 default:
685 ret = -EINPROGRESS;
686 goto out;
687 }
688
689 read_phase_complete:
690 ret = 1;
691 out:
692 switch (call->ackr_reason) {
693 case RXRPC_ACK_IDLE:
694 break;
695 case RXRPC_ACK_DELAY:
696 if (ret != -EAGAIN)
697 break;
698 /* Fall through */
699 default:
700 rxrpc_send_ack_packet(call, false, NULL);
701 }
702
703 if (_service)
704 *_service = call->service_id;
705 mutex_unlock(&call->user_mutex);
706 _leave(" = %d [%zu,%d]", ret, iov_iter_count(iter), *_abort);
707 return ret;
708
709 short_data:
710 trace_rxrpc_rx_eproto(call, 0, tracepoint_string("short_data"));
711 ret = -EBADMSG;
712 goto out;
713 excess_data:
714 trace_rxrpc_rx_eproto(call, 0, tracepoint_string("excess_data"));
715 ret = -EMSGSIZE;
716 goto out;
717 call_complete:
718 *_abort = call->abort_code;
719 ret = call->error;
720 if (call->completion == RXRPC_CALL_SUCCEEDED) {
721 ret = 1;
722 if (iov_iter_count(iter) > 0)
723 ret = -ECONNRESET;
724 }
725 goto out;
726 }
727 EXPORT_SYMBOL(rxrpc_kernel_recv_data);
728
729 /**
730 * rxrpc_kernel_get_reply_time - Get timestamp on first reply packet
731 * @sock: The socket that the call exists on
732 * @call: The call to query
733 * @_ts: Where to put the timestamp
734 *
735 * Retrieve the timestamp from the first DATA packet of the reply if it is
736 * in the ring. Returns true if successful, false if not.
737 */
rxrpc_kernel_get_reply_time(struct socket * sock,struct rxrpc_call * call,ktime_t * _ts)738 bool rxrpc_kernel_get_reply_time(struct socket *sock, struct rxrpc_call *call,
739 ktime_t *_ts)
740 {
741 struct sk_buff *skb;
742 rxrpc_seq_t hard_ack, top, seq;
743 bool success = false;
744
745 mutex_lock(&call->user_mutex);
746
747 if (READ_ONCE(call->state) != RXRPC_CALL_CLIENT_RECV_REPLY)
748 goto out;
749
750 hard_ack = call->rx_hard_ack;
751 if (hard_ack != 0)
752 goto out;
753
754 seq = hard_ack + 1;
755 top = smp_load_acquire(&call->rx_top);
756 if (after(seq, top))
757 goto out;
758
759 skb = call->rxtx_buffer[seq & RXRPC_RXTX_BUFF_MASK];
760 if (!skb)
761 goto out;
762
763 *_ts = skb_get_ktime(skb);
764 success = true;
765
766 out:
767 mutex_unlock(&call->user_mutex);
768 return success;
769 }
770 EXPORT_SYMBOL(rxrpc_kernel_get_reply_time);
771