xref: /linux/net/rxrpc/sendmsg.c (revision 497e6b37b0099dc415578488287fd84fb74433eb)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* AF_RXRPC sendmsg() implementation.
3  *
4  * Copyright (C) 2007, 2016 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/gfp.h>
12 #include <linux/skbuff.h>
13 #include <linux/export.h>
14 #include <linux/sched/signal.h>
15 
16 #include <net/sock.h>
17 #include <net/af_rxrpc.h>
18 #include "ar-internal.h"
19 
20 /*
21  * Return true if there's sufficient Tx queue space.
22  */
23 static bool rxrpc_check_tx_space(struct rxrpc_call *call, rxrpc_seq_t *_tx_win)
24 {
25 	if (_tx_win)
26 		*_tx_win = call->tx_bottom;
27 	return call->tx_prepared - call->tx_bottom < 256;
28 }
29 
30 /*
31  * Wait for space to appear in the Tx queue or a signal to occur.
32  */
33 static int rxrpc_wait_for_tx_window_intr(struct rxrpc_sock *rx,
34 					 struct rxrpc_call *call,
35 					 long *timeo)
36 {
37 	for (;;) {
38 		set_current_state(TASK_INTERRUPTIBLE);
39 		if (rxrpc_check_tx_space(call, NULL))
40 			return 0;
41 
42 		if (call->state >= RXRPC_CALL_COMPLETE)
43 			return call->error;
44 
45 		if (signal_pending(current))
46 			return sock_intr_errno(*timeo);
47 
48 		trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
49 		*timeo = schedule_timeout(*timeo);
50 	}
51 }
52 
53 /*
54  * Wait for space to appear in the Tx queue uninterruptibly, but with
55  * a timeout of 2*RTT if no progress was made and a signal occurred.
56  */
57 static int rxrpc_wait_for_tx_window_waitall(struct rxrpc_sock *rx,
58 					    struct rxrpc_call *call)
59 {
60 	rxrpc_seq_t tx_start, tx_win;
61 	signed long rtt, timeout;
62 
63 	rtt = READ_ONCE(call->peer->srtt_us) >> 3;
64 	rtt = usecs_to_jiffies(rtt) * 2;
65 	if (rtt < 2)
66 		rtt = 2;
67 
68 	timeout = rtt;
69 	tx_start = smp_load_acquire(&call->acks_hard_ack);
70 
71 	for (;;) {
72 		set_current_state(TASK_UNINTERRUPTIBLE);
73 
74 		if (rxrpc_check_tx_space(call, &tx_win))
75 			return 0;
76 
77 		if (call->state >= RXRPC_CALL_COMPLETE)
78 			return call->error;
79 
80 		if (timeout == 0 &&
81 		    tx_win == tx_start && signal_pending(current))
82 			return -EINTR;
83 
84 		if (tx_win != tx_start) {
85 			timeout = rtt;
86 			tx_start = tx_win;
87 		}
88 
89 		trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
90 		timeout = schedule_timeout(timeout);
91 	}
92 }
93 
94 /*
95  * Wait for space to appear in the Tx queue uninterruptibly.
96  */
97 static int rxrpc_wait_for_tx_window_nonintr(struct rxrpc_sock *rx,
98 					    struct rxrpc_call *call,
99 					    long *timeo)
100 {
101 	for (;;) {
102 		set_current_state(TASK_UNINTERRUPTIBLE);
103 		if (rxrpc_check_tx_space(call, NULL))
104 			return 0;
105 
106 		if (call->state >= RXRPC_CALL_COMPLETE)
107 			return call->error;
108 
109 		trace_rxrpc_txqueue(call, rxrpc_txqueue_wait);
110 		*timeo = schedule_timeout(*timeo);
111 	}
112 }
113 
114 /*
115  * wait for space to appear in the transmit/ACK window
116  * - caller holds the socket locked
117  */
118 static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
119 				    struct rxrpc_call *call,
120 				    long *timeo,
121 				    bool waitall)
122 {
123 	DECLARE_WAITQUEUE(myself, current);
124 	int ret;
125 
126 	_enter(",{%u,%u,%u,%u}",
127 	       call->tx_bottom, call->acks_hard_ack, call->tx_top, call->tx_winsize);
128 
129 	add_wait_queue(&call->waitq, &myself);
130 
131 	switch (call->interruptibility) {
132 	case RXRPC_INTERRUPTIBLE:
133 		if (waitall)
134 			ret = rxrpc_wait_for_tx_window_waitall(rx, call);
135 		else
136 			ret = rxrpc_wait_for_tx_window_intr(rx, call, timeo);
137 		break;
138 	case RXRPC_PREINTERRUPTIBLE:
139 	case RXRPC_UNINTERRUPTIBLE:
140 	default:
141 		ret = rxrpc_wait_for_tx_window_nonintr(rx, call, timeo);
142 		break;
143 	}
144 
145 	remove_wait_queue(&call->waitq, &myself);
146 	set_current_state(TASK_RUNNING);
147 	_leave(" = %d", ret);
148 	return ret;
149 }
150 
151 /*
152  * Notify the owner of the call that the transmit phase is ended and the last
153  * packet has been queued.
154  */
155 static void rxrpc_notify_end_tx(struct rxrpc_sock *rx, struct rxrpc_call *call,
156 				rxrpc_notify_end_tx_t notify_end_tx)
157 {
158 	if (notify_end_tx)
159 		notify_end_tx(&rx->sk, call, call->user_call_ID);
160 }
161 
162 /*
163  * Queue a DATA packet for transmission, set the resend timeout and send
164  * the packet immediately.  Returns the error from rxrpc_send_data_packet()
165  * in case the caller wants to do something with it.
166  */
167 static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
168 			       struct rxrpc_txbuf *txb,
169 			       rxrpc_notify_end_tx_t notify_end_tx)
170 {
171 	unsigned long now;
172 	rxrpc_seq_t seq = txb->seq;
173 	bool last = test_bit(RXRPC_TXBUF_LAST, &txb->flags), poke;
174 
175 	rxrpc_inc_stat(call->rxnet, stat_tx_data);
176 
177 	ASSERTCMP(txb->seq, ==, call->tx_prepared + 1);
178 
179 	/* We have to set the timestamp before queueing as the retransmit
180 	 * algorithm can see the packet as soon as we queue it.
181 	 */
182 	txb->last_sent = ktime_get_real();
183 
184 	if (last)
185 		trace_rxrpc_txqueue(call, rxrpc_txqueue_queue_last);
186 	else
187 		trace_rxrpc_txqueue(call, rxrpc_txqueue_queue);
188 
189 	/* Add the packet to the call's output buffer */
190 	spin_lock(&call->tx_lock);
191 	poke = list_empty(&call->tx_sendmsg);
192 	list_add_tail(&txb->call_link, &call->tx_sendmsg);
193 	call->tx_prepared = seq;
194 	spin_unlock(&call->tx_lock);
195 
196 	if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
197 		_debug("________awaiting reply/ACK__________");
198 		write_lock(&call->state_lock);
199 		switch (call->state) {
200 		case RXRPC_CALL_CLIENT_SEND_REQUEST:
201 			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
202 			rxrpc_notify_end_tx(rx, call, notify_end_tx);
203 			break;
204 		case RXRPC_CALL_SERVER_ACK_REQUEST:
205 			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
206 			now = jiffies;
207 			WRITE_ONCE(call->delay_ack_at, now + MAX_JIFFY_OFFSET);
208 			if (call->ackr_reason == RXRPC_ACK_DELAY)
209 				call->ackr_reason = 0;
210 			trace_rxrpc_timer(call, rxrpc_timer_init_for_send_reply, now);
211 			if (!last)
212 				break;
213 			fallthrough;
214 		case RXRPC_CALL_SERVER_SEND_REPLY:
215 			call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
216 			rxrpc_notify_end_tx(rx, call, notify_end_tx);
217 			break;
218 		default:
219 			break;
220 		}
221 		write_unlock(&call->state_lock);
222 	}
223 
224 	if (poke)
225 		rxrpc_poke_call(call, rxrpc_call_poke_start);
226 }
227 
228 /*
229  * send data through a socket
230  * - must be called in process context
231  * - The caller holds the call user access mutex, but not the socket lock.
232  */
233 static int rxrpc_send_data(struct rxrpc_sock *rx,
234 			   struct rxrpc_call *call,
235 			   struct msghdr *msg, size_t len,
236 			   rxrpc_notify_end_tx_t notify_end_tx,
237 			   bool *_dropped_lock)
238 {
239 	struct rxrpc_txbuf *txb;
240 	struct sock *sk = &rx->sk;
241 	enum rxrpc_call_state state;
242 	long timeo;
243 	bool more = msg->msg_flags & MSG_MORE;
244 	int ret, copied = 0;
245 
246 	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
247 
248 	/* this should be in poll */
249 	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
250 
251 reload:
252 	ret = -EPIPE;
253 	if (sk->sk_shutdown & SEND_SHUTDOWN)
254 		goto maybe_error;
255 	state = READ_ONCE(call->state);
256 	ret = -ESHUTDOWN;
257 	if (state >= RXRPC_CALL_COMPLETE)
258 		goto maybe_error;
259 	ret = -EPROTO;
260 	if (state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
261 	    state != RXRPC_CALL_SERVER_ACK_REQUEST &&
262 	    state != RXRPC_CALL_SERVER_SEND_REPLY)
263 		goto maybe_error;
264 
265 	ret = -EMSGSIZE;
266 	if (call->tx_total_len != -1) {
267 		if (len - copied > call->tx_total_len)
268 			goto maybe_error;
269 		if (!more && len - copied != call->tx_total_len)
270 			goto maybe_error;
271 	}
272 
273 	txb = call->tx_pending;
274 	call->tx_pending = NULL;
275 	if (txb)
276 		rxrpc_see_txbuf(txb, rxrpc_txbuf_see_send_more);
277 
278 	do {
279 		if (!txb) {
280 			size_t remain, bufsize, chunk, offset;
281 
282 			_debug("alloc");
283 
284 			if (!rxrpc_check_tx_space(call, NULL))
285 				goto wait_for_space;
286 
287 			/* Work out the maximum size of a packet.  Assume that
288 			 * the security header is going to be in the padded
289 			 * region (enc blocksize), but the trailer is not.
290 			 */
291 			remain = more ? INT_MAX : msg_data_left(msg);
292 			ret = call->conn->security->how_much_data(call, remain,
293 								  &bufsize, &chunk, &offset);
294 			if (ret < 0)
295 				goto maybe_error;
296 
297 			_debug("SIZE: %zu/%zu @%zu", chunk, bufsize, offset);
298 
299 			/* create a buffer that we can retain until it's ACK'd */
300 			ret = -ENOMEM;
301 			txb = rxrpc_alloc_txbuf(call, RXRPC_PACKET_TYPE_DATA,
302 						GFP_KERNEL);
303 			if (!txb)
304 				goto maybe_error;
305 
306 			txb->offset = offset;
307 			txb->space -= offset;
308 			txb->space = min_t(size_t, chunk, txb->space);
309 		}
310 
311 		_debug("append");
312 
313 		/* append next segment of data to the current buffer */
314 		if (msg_data_left(msg) > 0) {
315 			size_t copy = min_t(size_t, txb->space, msg_data_left(msg));
316 
317 			_debug("add %zu", copy);
318 			if (!copy_from_iter_full(txb->data + txb->offset, copy,
319 						 &msg->msg_iter))
320 				goto efault;
321 			_debug("added");
322 			txb->space -= copy;
323 			txb->len += copy;
324 			txb->offset += copy;
325 			copied += copy;
326 			if (call->tx_total_len != -1)
327 				call->tx_total_len -= copy;
328 		}
329 
330 		/* check for the far side aborting the call or a network error
331 		 * occurring */
332 		if (call->state == RXRPC_CALL_COMPLETE)
333 			goto call_terminated;
334 
335 		/* add the packet to the send queue if it's now full */
336 		if (!txb->space ||
337 		    (msg_data_left(msg) == 0 && !more)) {
338 			if (msg_data_left(msg) == 0 && !more) {
339 				txb->wire.flags |= RXRPC_LAST_PACKET;
340 				__set_bit(RXRPC_TXBUF_LAST, &txb->flags);
341 			}
342 			else if (call->tx_top - call->acks_hard_ack <
343 				 call->tx_winsize)
344 				txb->wire.flags |= RXRPC_MORE_PACKETS;
345 
346 			ret = call->security->secure_packet(call, txb);
347 			if (ret < 0)
348 				goto out;
349 
350 			rxrpc_queue_packet(rx, call, txb, notify_end_tx);
351 			txb = NULL;
352 		}
353 	} while (msg_data_left(msg) > 0);
354 
355 success:
356 	ret = copied;
357 	if (READ_ONCE(call->state) == RXRPC_CALL_COMPLETE) {
358 		read_lock(&call->state_lock);
359 		if (call->error < 0)
360 			ret = call->error;
361 		read_unlock(&call->state_lock);
362 	}
363 out:
364 	call->tx_pending = txb;
365 	_leave(" = %d", ret);
366 	return ret;
367 
368 call_terminated:
369 	rxrpc_put_txbuf(txb, rxrpc_txbuf_put_send_aborted);
370 	_leave(" = %d", call->error);
371 	return call->error;
372 
373 maybe_error:
374 	if (copied)
375 		goto success;
376 	goto out;
377 
378 efault:
379 	ret = -EFAULT;
380 	goto out;
381 
382 wait_for_space:
383 	ret = -EAGAIN;
384 	if (msg->msg_flags & MSG_DONTWAIT)
385 		goto maybe_error;
386 	mutex_unlock(&call->user_mutex);
387 	*_dropped_lock = true;
388 	ret = rxrpc_wait_for_tx_window(rx, call, &timeo,
389 				       msg->msg_flags & MSG_WAITALL);
390 	if (ret < 0)
391 		goto maybe_error;
392 	if (call->interruptibility == RXRPC_INTERRUPTIBLE) {
393 		if (mutex_lock_interruptible(&call->user_mutex) < 0) {
394 			ret = sock_intr_errno(timeo);
395 			goto maybe_error;
396 		}
397 	} else {
398 		mutex_lock(&call->user_mutex);
399 	}
400 	*_dropped_lock = false;
401 	goto reload;
402 }
403 
404 /*
405  * extract control messages from the sendmsg() control buffer
406  */
407 static int rxrpc_sendmsg_cmsg(struct msghdr *msg, struct rxrpc_send_params *p)
408 {
409 	struct cmsghdr *cmsg;
410 	bool got_user_ID = false;
411 	int len;
412 
413 	if (msg->msg_controllen == 0)
414 		return -EINVAL;
415 
416 	for_each_cmsghdr(cmsg, msg) {
417 		if (!CMSG_OK(msg, cmsg))
418 			return -EINVAL;
419 
420 		len = cmsg->cmsg_len - sizeof(struct cmsghdr);
421 		_debug("CMSG %d, %d, %d",
422 		       cmsg->cmsg_level, cmsg->cmsg_type, len);
423 
424 		if (cmsg->cmsg_level != SOL_RXRPC)
425 			continue;
426 
427 		switch (cmsg->cmsg_type) {
428 		case RXRPC_USER_CALL_ID:
429 			if (msg->msg_flags & MSG_CMSG_COMPAT) {
430 				if (len != sizeof(u32))
431 					return -EINVAL;
432 				p->call.user_call_ID = *(u32 *)CMSG_DATA(cmsg);
433 			} else {
434 				if (len != sizeof(unsigned long))
435 					return -EINVAL;
436 				p->call.user_call_ID = *(unsigned long *)
437 					CMSG_DATA(cmsg);
438 			}
439 			got_user_ID = true;
440 			break;
441 
442 		case RXRPC_ABORT:
443 			if (p->command != RXRPC_CMD_SEND_DATA)
444 				return -EINVAL;
445 			p->command = RXRPC_CMD_SEND_ABORT;
446 			if (len != sizeof(p->abort_code))
447 				return -EINVAL;
448 			p->abort_code = *(unsigned int *)CMSG_DATA(cmsg);
449 			if (p->abort_code == 0)
450 				return -EINVAL;
451 			break;
452 
453 		case RXRPC_CHARGE_ACCEPT:
454 			if (p->command != RXRPC_CMD_SEND_DATA)
455 				return -EINVAL;
456 			p->command = RXRPC_CMD_CHARGE_ACCEPT;
457 			if (len != 0)
458 				return -EINVAL;
459 			break;
460 
461 		case RXRPC_EXCLUSIVE_CALL:
462 			p->exclusive = true;
463 			if (len != 0)
464 				return -EINVAL;
465 			break;
466 
467 		case RXRPC_UPGRADE_SERVICE:
468 			p->upgrade = true;
469 			if (len != 0)
470 				return -EINVAL;
471 			break;
472 
473 		case RXRPC_TX_LENGTH:
474 			if (p->call.tx_total_len != -1 || len != sizeof(__s64))
475 				return -EINVAL;
476 			p->call.tx_total_len = *(__s64 *)CMSG_DATA(cmsg);
477 			if (p->call.tx_total_len < 0)
478 				return -EINVAL;
479 			break;
480 
481 		case RXRPC_SET_CALL_TIMEOUT:
482 			if (len & 3 || len < 4 || len > 12)
483 				return -EINVAL;
484 			memcpy(&p->call.timeouts, CMSG_DATA(cmsg), len);
485 			p->call.nr_timeouts = len / 4;
486 			if (p->call.timeouts.hard > INT_MAX / HZ)
487 				return -ERANGE;
488 			if (p->call.nr_timeouts >= 2 && p->call.timeouts.idle > 60 * 60 * 1000)
489 				return -ERANGE;
490 			if (p->call.nr_timeouts >= 3 && p->call.timeouts.normal > 60 * 60 * 1000)
491 				return -ERANGE;
492 			break;
493 
494 		default:
495 			return -EINVAL;
496 		}
497 	}
498 
499 	if (!got_user_ID)
500 		return -EINVAL;
501 	if (p->call.tx_total_len != -1 && p->command != RXRPC_CMD_SEND_DATA)
502 		return -EINVAL;
503 	_leave(" = 0");
504 	return 0;
505 }
506 
507 /*
508  * Create a new client call for sendmsg().
509  * - Called with the socket lock held, which it must release.
510  * - If it returns a call, the call's lock will need releasing by the caller.
511  */
512 static struct rxrpc_call *
513 rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
514 				  struct rxrpc_send_params *p)
515 	__releases(&rx->sk.sk_lock.slock)
516 	__acquires(&call->user_mutex)
517 {
518 	struct rxrpc_conn_parameters cp;
519 	struct rxrpc_call *call;
520 	struct key *key;
521 
522 	DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
523 
524 	_enter("");
525 
526 	if (!msg->msg_name) {
527 		release_sock(&rx->sk);
528 		return ERR_PTR(-EDESTADDRREQ);
529 	}
530 
531 	key = rx->key;
532 	if (key && !rx->key->payload.data[0])
533 		key = NULL;
534 
535 	memset(&cp, 0, sizeof(cp));
536 	cp.local		= rx->local;
537 	cp.key			= rx->key;
538 	cp.security_level	= rx->min_sec_level;
539 	cp.exclusive		= rx->exclusive | p->exclusive;
540 	cp.upgrade		= p->upgrade;
541 	cp.service_id		= srx->srx_service;
542 	call = rxrpc_new_client_call(rx, &cp, srx, &p->call, GFP_KERNEL,
543 				     atomic_inc_return(&rxrpc_debug_id));
544 	/* The socket is now unlocked */
545 
546 	rxrpc_put_peer(cp.peer, rxrpc_peer_put_discard_tmp);
547 	_leave(" = %p\n", call);
548 	return call;
549 }
550 
551 /*
552  * send a message forming part of a client call through an RxRPC socket
553  * - caller holds the socket locked
554  * - the socket may be either a client socket or a server socket
555  */
556 int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
557 	__releases(&rx->sk.sk_lock.slock)
558 {
559 	enum rxrpc_call_state state;
560 	struct rxrpc_call *call;
561 	unsigned long now, j;
562 	bool dropped_lock = false;
563 	int ret;
564 
565 	struct rxrpc_send_params p = {
566 		.call.tx_total_len	= -1,
567 		.call.user_call_ID	= 0,
568 		.call.nr_timeouts	= 0,
569 		.call.interruptibility	= RXRPC_INTERRUPTIBLE,
570 		.abort_code		= 0,
571 		.command		= RXRPC_CMD_SEND_DATA,
572 		.exclusive		= false,
573 		.upgrade		= false,
574 	};
575 
576 	_enter("");
577 
578 	ret = rxrpc_sendmsg_cmsg(msg, &p);
579 	if (ret < 0)
580 		goto error_release_sock;
581 
582 	if (p.command == RXRPC_CMD_CHARGE_ACCEPT) {
583 		ret = -EINVAL;
584 		if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
585 			goto error_release_sock;
586 		ret = rxrpc_user_charge_accept(rx, p.call.user_call_ID);
587 		goto error_release_sock;
588 	}
589 
590 	call = rxrpc_find_call_by_user_ID(rx, p.call.user_call_ID);
591 	if (!call) {
592 		ret = -EBADSLT;
593 		if (p.command != RXRPC_CMD_SEND_DATA)
594 			goto error_release_sock;
595 		call = rxrpc_new_client_call_for_sendmsg(rx, msg, &p);
596 		/* The socket is now unlocked... */
597 		if (IS_ERR(call))
598 			return PTR_ERR(call);
599 		/* ... and we have the call lock. */
600 		ret = 0;
601 		if (READ_ONCE(call->state) == RXRPC_CALL_COMPLETE)
602 			goto out_put_unlock;
603 	} else {
604 		switch (READ_ONCE(call->state)) {
605 		case RXRPC_CALL_UNINITIALISED:
606 		case RXRPC_CALL_CLIENT_AWAIT_CONN:
607 		case RXRPC_CALL_SERVER_PREALLOC:
608 		case RXRPC_CALL_SERVER_SECURING:
609 			rxrpc_put_call(call, rxrpc_call_put_sendmsg);
610 			ret = -EBUSY;
611 			goto error_release_sock;
612 		default:
613 			break;
614 		}
615 
616 		ret = mutex_lock_interruptible(&call->user_mutex);
617 		release_sock(&rx->sk);
618 		if (ret < 0) {
619 			ret = -ERESTARTSYS;
620 			goto error_put;
621 		}
622 
623 		if (p.call.tx_total_len != -1) {
624 			ret = -EINVAL;
625 			if (call->tx_total_len != -1 ||
626 			    call->tx_pending ||
627 			    call->tx_top != 0)
628 				goto out_put_unlock;
629 			call->tx_total_len = p.call.tx_total_len;
630 		}
631 	}
632 
633 	switch (p.call.nr_timeouts) {
634 	case 3:
635 		j = msecs_to_jiffies(p.call.timeouts.normal);
636 		if (p.call.timeouts.normal > 0 && j == 0)
637 			j = 1;
638 		WRITE_ONCE(call->next_rx_timo, j);
639 		fallthrough;
640 	case 2:
641 		j = msecs_to_jiffies(p.call.timeouts.idle);
642 		if (p.call.timeouts.idle > 0 && j == 0)
643 			j = 1;
644 		WRITE_ONCE(call->next_req_timo, j);
645 		fallthrough;
646 	case 1:
647 		if (p.call.timeouts.hard > 0) {
648 			j = msecs_to_jiffies(p.call.timeouts.hard);
649 			now = jiffies;
650 			j += now;
651 			WRITE_ONCE(call->expect_term_by, j);
652 			rxrpc_reduce_call_timer(call, j, now,
653 						rxrpc_timer_set_for_hard);
654 		}
655 		break;
656 	}
657 
658 	state = READ_ONCE(call->state);
659 	_debug("CALL %d USR %lx ST %d on CONN %p",
660 	       call->debug_id, call->user_call_ID, state, call->conn);
661 
662 	if (state >= RXRPC_CALL_COMPLETE) {
663 		/* it's too late for this call */
664 		ret = -ESHUTDOWN;
665 	} else if (p.command == RXRPC_CMD_SEND_ABORT) {
666 		ret = 0;
667 		if (rxrpc_abort_call("CMD", call, 0, p.abort_code, -ECONNABORTED))
668 			ret = rxrpc_send_abort_packet(call);
669 	} else if (p.command != RXRPC_CMD_SEND_DATA) {
670 		ret = -EINVAL;
671 	} else {
672 		ret = rxrpc_send_data(rx, call, msg, len, NULL, &dropped_lock);
673 	}
674 
675 out_put_unlock:
676 	if (!dropped_lock)
677 		mutex_unlock(&call->user_mutex);
678 error_put:
679 	rxrpc_put_call(call, rxrpc_call_put_sendmsg);
680 	_leave(" = %d", ret);
681 	return ret;
682 
683 error_release_sock:
684 	release_sock(&rx->sk);
685 	return ret;
686 }
687 
688 /**
689  * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
690  * @sock: The socket the call is on
691  * @call: The call to send data through
692  * @msg: The data to send
693  * @len: The amount of data to send
694  * @notify_end_tx: Notification that the last packet is queued.
695  *
696  * Allow a kernel service to send data on a call.  The call must be in an state
697  * appropriate to sending data.  No control data should be supplied in @msg,
698  * nor should an address be supplied.  MSG_MORE should be flagged if there's
699  * more data to come, otherwise this data will end the transmission phase.
700  */
701 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
702 			   struct msghdr *msg, size_t len,
703 			   rxrpc_notify_end_tx_t notify_end_tx)
704 {
705 	bool dropped_lock = false;
706 	int ret;
707 
708 	_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
709 
710 	ASSERTCMP(msg->msg_name, ==, NULL);
711 	ASSERTCMP(msg->msg_control, ==, NULL);
712 
713 	mutex_lock(&call->user_mutex);
714 
715 	_debug("CALL %d USR %lx ST %d on CONN %p",
716 	       call->debug_id, call->user_call_ID, call->state, call->conn);
717 
718 	switch (READ_ONCE(call->state)) {
719 	case RXRPC_CALL_CLIENT_SEND_REQUEST:
720 	case RXRPC_CALL_SERVER_ACK_REQUEST:
721 	case RXRPC_CALL_SERVER_SEND_REPLY:
722 		ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len,
723 				      notify_end_tx, &dropped_lock);
724 		break;
725 	case RXRPC_CALL_COMPLETE:
726 		read_lock(&call->state_lock);
727 		ret = call->error;
728 		read_unlock(&call->state_lock);
729 		break;
730 	default:
731 		/* Request phase complete for this client call */
732 		trace_rxrpc_rx_eproto(call, 0, tracepoint_string("late_send"));
733 		ret = -EPROTO;
734 		break;
735 	}
736 
737 	if (!dropped_lock)
738 		mutex_unlock(&call->user_mutex);
739 	_leave(" = %d", ret);
740 	return ret;
741 }
742 EXPORT_SYMBOL(rxrpc_kernel_send_data);
743 
744 /**
745  * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
746  * @sock: The socket the call is on
747  * @call: The call to be aborted
748  * @abort_code: The abort code to stick into the ABORT packet
749  * @error: Local error value
750  * @why: 3-char string indicating why.
751  *
752  * Allow a kernel service to abort a call, if it's still in an abortable state
753  * and return true if the call was aborted, false if it was already complete.
754  */
755 bool rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
756 			     u32 abort_code, int error, const char *why)
757 {
758 	bool aborted;
759 
760 	_enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
761 
762 	mutex_lock(&call->user_mutex);
763 
764 	aborted = rxrpc_abort_call(why, call, 0, abort_code, error);
765 	if (aborted)
766 		rxrpc_send_abort_packet(call);
767 
768 	mutex_unlock(&call->user_mutex);
769 	return aborted;
770 }
771 EXPORT_SYMBOL(rxrpc_kernel_abort_call);
772 
773 /**
774  * rxrpc_kernel_set_tx_length - Set the total Tx length on a call
775  * @sock: The socket the call is on
776  * @call: The call to be informed
777  * @tx_total_len: The amount of data to be transmitted for this call
778  *
779  * Allow a kernel service to set the total transmit length on a call.  This
780  * allows buffer-to-packet encrypt-and-copy to be performed.
781  *
782  * This function is primarily for use for setting the reply length since the
783  * request length can be set when beginning the call.
784  */
785 void rxrpc_kernel_set_tx_length(struct socket *sock, struct rxrpc_call *call,
786 				s64 tx_total_len)
787 {
788 	WARN_ON(call->tx_total_len != -1);
789 	call->tx_total_len = tx_total_len;
790 }
791 EXPORT_SYMBOL(rxrpc_kernel_set_tx_length);
792