xref: /openbmc/linux/net/rxrpc/sendmsg.c (revision 2eb3ed33e55d003d721d4d1a5e72fe323c12b4c0)
1 /* AF_RXRPC sendmsg() implementation.
2  *
3  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public Licence
8  * as published by the Free Software Foundation; either version
9  * 2 of the Licence, or (at your option) any later version.
10  */
11 
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 
14 #include <linux/net.h>
15 #include <linux/gfp.h>
16 #include <linux/skbuff.h>
17 #include <linux/export.h>
18 #include <linux/sched/signal.h>
19 
20 #include <net/sock.h>
21 #include <net/af_rxrpc.h>
22 #include "ar-internal.h"
23 
24 enum rxrpc_command {
25 	RXRPC_CMD_SEND_DATA,		/* send data message */
26 	RXRPC_CMD_SEND_ABORT,		/* request abort generation */
27 	RXRPC_CMD_ACCEPT,		/* [server] accept incoming call */
28 	RXRPC_CMD_REJECT_BUSY,		/* [server] reject a call as busy */
29 };
30 
31 struct rxrpc_send_params {
32 	s64			tx_total_len;	/* Total Tx data length (if send data) */
33 	unsigned long		user_call_ID;	/* User's call ID */
34 	u32			abort_code;	/* Abort code to Tx (if abort) */
35 	enum rxrpc_command	command : 8;	/* The command to implement */
36 	bool			exclusive;	/* Shared or exclusive call */
37 	bool			upgrade;	/* If the connection is upgradeable */
38 };
39 
40 /*
41  * Wait for space to appear in the Tx queue or a signal to occur.
42  */
43 static int rxrpc_wait_for_tx_window_intr(struct rxrpc_sock *rx,
44 					 struct rxrpc_call *call,
45 					 long *timeo)
46 {
47 	for (;;) {
48 		set_current_state(TASK_INTERRUPTIBLE);
49 		if (call->tx_top - call->tx_hard_ack <
50 		    min_t(unsigned int, call->tx_winsize,
51 			  call->cong_cwnd + call->cong_extra))
52 			return 0;
53 
54 		if (call->state >= RXRPC_CALL_COMPLETE)
55 			return call->error;
56 
57 		if (signal_pending(current))
58 			return sock_intr_errno(*timeo);
59 
60 		trace_rxrpc_transmit(call, rxrpc_transmit_wait);
61 		mutex_unlock(&call->user_mutex);
62 		*timeo = schedule_timeout(*timeo);
63 		if (mutex_lock_interruptible(&call->user_mutex) < 0)
64 			return sock_intr_errno(*timeo);
65 	}
66 }
67 
68 /*
69  * Wait for space to appear in the Tx queue uninterruptibly, but with
70  * a timeout of 2*RTT if no progress was made and a signal occurred.
71  */
72 static int rxrpc_wait_for_tx_window_nonintr(struct rxrpc_sock *rx,
73 					    struct rxrpc_call *call)
74 {
75 	rxrpc_seq_t tx_start, tx_win;
76 	signed long rtt2, timeout;
77 	u64 rtt;
78 
79 	rtt = READ_ONCE(call->peer->rtt);
80 	rtt2 = nsecs_to_jiffies64(rtt) * 2;
81 	if (rtt2 < 1)
82 		rtt2 = 1;
83 
84 	timeout = rtt2;
85 	tx_start = READ_ONCE(call->tx_hard_ack);
86 
87 	for (;;) {
88 		set_current_state(TASK_UNINTERRUPTIBLE);
89 
90 		tx_win = READ_ONCE(call->tx_hard_ack);
91 		if (call->tx_top - tx_win <
92 		    min_t(unsigned int, call->tx_winsize,
93 			  call->cong_cwnd + call->cong_extra))
94 			return 0;
95 
96 		if (call->state >= RXRPC_CALL_COMPLETE)
97 			return call->error;
98 
99 		if (timeout == 0 &&
100 		    tx_win == tx_start && signal_pending(current))
101 			return -EINTR;
102 
103 		if (tx_win != tx_start) {
104 			timeout = rtt2;
105 			tx_start = tx_win;
106 		}
107 
108 		trace_rxrpc_transmit(call, rxrpc_transmit_wait);
109 		timeout = schedule_timeout(timeout);
110 	}
111 }
112 
113 /*
114  * wait for space to appear in the transmit/ACK window
115  * - caller holds the socket locked
116  */
117 static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
118 				    struct rxrpc_call *call,
119 				    long *timeo,
120 				    bool waitall)
121 {
122 	DECLARE_WAITQUEUE(myself, current);
123 	int ret;
124 
125 	_enter(",{%u,%u,%u}",
126 	       call->tx_hard_ack, call->tx_top, call->tx_winsize);
127 
128 	add_wait_queue(&call->waitq, &myself);
129 
130 	if (waitall)
131 		ret = rxrpc_wait_for_tx_window_nonintr(rx, call);
132 	else
133 		ret = rxrpc_wait_for_tx_window_intr(rx, call, timeo);
134 
135 	remove_wait_queue(&call->waitq, &myself);
136 	set_current_state(TASK_RUNNING);
137 	_leave(" = %d", ret);
138 	return ret;
139 }
140 
141 /*
142  * Schedule an instant Tx resend.
143  */
144 static inline void rxrpc_instant_resend(struct rxrpc_call *call, int ix)
145 {
146 	spin_lock_bh(&call->lock);
147 
148 	if (call->state < RXRPC_CALL_COMPLETE) {
149 		call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
150 		if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
151 			rxrpc_queue_call(call);
152 	}
153 
154 	spin_unlock_bh(&call->lock);
155 }
156 
157 /*
158  * Notify the owner of the call that the transmit phase is ended and the last
159  * packet has been queued.
160  */
161 static void rxrpc_notify_end_tx(struct rxrpc_sock *rx, struct rxrpc_call *call,
162 				rxrpc_notify_end_tx_t notify_end_tx)
163 {
164 	if (notify_end_tx)
165 		notify_end_tx(&rx->sk, call, call->user_call_ID);
166 }
167 
168 /*
169  * Queue a DATA packet for transmission, set the resend timeout and send the
170  * packet immediately
171  */
172 static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
173 			       struct sk_buff *skb, bool last,
174 			       rxrpc_notify_end_tx_t notify_end_tx)
175 {
176 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
177 	rxrpc_seq_t seq = sp->hdr.seq;
178 	int ret, ix;
179 	u8 annotation = RXRPC_TX_ANNO_UNACK;
180 
181 	_net("queue skb %p [%d]", skb, seq);
182 
183 	ASSERTCMP(seq, ==, call->tx_top + 1);
184 
185 	if (last) {
186 		annotation |= RXRPC_TX_ANNO_LAST;
187 		set_bit(RXRPC_CALL_TX_LASTQ, &call->flags);
188 	}
189 
190 	/* We have to set the timestamp before queueing as the retransmit
191 	 * algorithm can see the packet as soon as we queue it.
192 	 */
193 	skb->tstamp = ktime_get_real();
194 
195 	ix = seq & RXRPC_RXTX_BUFF_MASK;
196 	rxrpc_get_skb(skb, rxrpc_skb_tx_got);
197 	call->rxtx_annotations[ix] = annotation;
198 	smp_wmb();
199 	call->rxtx_buffer[ix] = skb;
200 	call->tx_top = seq;
201 	if (last)
202 		trace_rxrpc_transmit(call, rxrpc_transmit_queue_last);
203 	else
204 		trace_rxrpc_transmit(call, rxrpc_transmit_queue);
205 
206 	if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
207 		_debug("________awaiting reply/ACK__________");
208 		write_lock_bh(&call->state_lock);
209 		switch (call->state) {
210 		case RXRPC_CALL_CLIENT_SEND_REQUEST:
211 			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
212 			rxrpc_notify_end_tx(rx, call, notify_end_tx);
213 			break;
214 		case RXRPC_CALL_SERVER_ACK_REQUEST:
215 			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
216 			call->ack_at = call->expire_at;
217 			if (call->ackr_reason == RXRPC_ACK_DELAY)
218 				call->ackr_reason = 0;
219 			__rxrpc_set_timer(call, rxrpc_timer_init_for_send_reply,
220 					  ktime_get_real());
221 			if (!last)
222 				break;
223 			/* Fall through */
224 		case RXRPC_CALL_SERVER_SEND_REPLY:
225 			call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
226 			rxrpc_notify_end_tx(rx, call, notify_end_tx);
227 			break;
228 		default:
229 			break;
230 		}
231 		write_unlock_bh(&call->state_lock);
232 	}
233 
234 	if (seq == 1 && rxrpc_is_client_call(call))
235 		rxrpc_expose_client_call(call);
236 
237 	ret = rxrpc_send_data_packet(call, skb, false);
238 	if (ret < 0) {
239 		_debug("need instant resend %d", ret);
240 		rxrpc_instant_resend(call, ix);
241 	} else {
242 		ktime_t now = ktime_get_real(), resend_at;
243 
244 		resend_at = ktime_add_ms(now, rxrpc_resend_timeout);
245 
246 		if (ktime_before(resend_at, call->resend_at)) {
247 			call->resend_at = resend_at;
248 			rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
249 		}
250 	}
251 
252 	rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
253 	_leave("");
254 }
255 
256 /*
257  * send data through a socket
258  * - must be called in process context
259  * - The caller holds the call user access mutex, but not the socket lock.
260  */
261 static int rxrpc_send_data(struct rxrpc_sock *rx,
262 			   struct rxrpc_call *call,
263 			   struct msghdr *msg, size_t len,
264 			   rxrpc_notify_end_tx_t notify_end_tx)
265 {
266 	struct rxrpc_skb_priv *sp;
267 	struct sk_buff *skb;
268 	struct sock *sk = &rx->sk;
269 	long timeo;
270 	bool more;
271 	int ret, copied;
272 
273 	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
274 
275 	/* this should be in poll */
276 	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
277 
278 	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
279 		return -EPIPE;
280 
281 	more = msg->msg_flags & MSG_MORE;
282 
283 	if (call->tx_total_len != -1) {
284 		if (len > call->tx_total_len)
285 			return -EMSGSIZE;
286 		if (!more && len != call->tx_total_len)
287 			return -EMSGSIZE;
288 	}
289 
290 	skb = call->tx_pending;
291 	call->tx_pending = NULL;
292 	rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
293 
294 	copied = 0;
295 	do {
296 		/* Check to see if there's a ping ACK to reply to. */
297 		if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE)
298 			rxrpc_send_ack_packet(call, false);
299 
300 		if (!skb) {
301 			size_t size, chunk, max, space;
302 
303 			_debug("alloc");
304 
305 			if (call->tx_top - call->tx_hard_ack >=
306 			    min_t(unsigned int, call->tx_winsize,
307 				  call->cong_cwnd + call->cong_extra)) {
308 				ret = -EAGAIN;
309 				if (msg->msg_flags & MSG_DONTWAIT)
310 					goto maybe_error;
311 				ret = rxrpc_wait_for_tx_window(rx, call,
312 							       &timeo,
313 							       msg->msg_flags & MSG_WAITALL);
314 				if (ret < 0)
315 					goto maybe_error;
316 			}
317 
318 			max = RXRPC_JUMBO_DATALEN;
319 			max -= call->conn->security_size;
320 			max &= ~(call->conn->size_align - 1UL);
321 
322 			chunk = max;
323 			if (chunk > msg_data_left(msg) && !more)
324 				chunk = msg_data_left(msg);
325 
326 			space = chunk + call->conn->size_align;
327 			space &= ~(call->conn->size_align - 1UL);
328 
329 			size = space + call->conn->security_size;
330 
331 			_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
332 
333 			/* create a buffer that we can retain until it's ACK'd */
334 			skb = sock_alloc_send_skb(
335 				sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
336 			if (!skb)
337 				goto maybe_error;
338 
339 			rxrpc_new_skb(skb, rxrpc_skb_tx_new);
340 
341 			_debug("ALLOC SEND %p", skb);
342 
343 			ASSERTCMP(skb->mark, ==, 0);
344 
345 			_debug("HS: %u", call->conn->security_size);
346 			skb_reserve(skb, call->conn->security_size);
347 			skb->len += call->conn->security_size;
348 
349 			sp = rxrpc_skb(skb);
350 			sp->remain = chunk;
351 			if (sp->remain > skb_tailroom(skb))
352 				sp->remain = skb_tailroom(skb);
353 
354 			_net("skb: hr %d, tr %d, hl %d, rm %d",
355 			       skb_headroom(skb),
356 			       skb_tailroom(skb),
357 			       skb_headlen(skb),
358 			       sp->remain);
359 
360 			skb->ip_summed = CHECKSUM_UNNECESSARY;
361 		}
362 
363 		_debug("append");
364 		sp = rxrpc_skb(skb);
365 
366 		/* append next segment of data to the current buffer */
367 		if (msg_data_left(msg) > 0) {
368 			int copy = skb_tailroom(skb);
369 			ASSERTCMP(copy, >, 0);
370 			if (copy > msg_data_left(msg))
371 				copy = msg_data_left(msg);
372 			if (copy > sp->remain)
373 				copy = sp->remain;
374 
375 			_debug("add");
376 			ret = skb_add_data(skb, &msg->msg_iter, copy);
377 			_debug("added");
378 			if (ret < 0)
379 				goto efault;
380 			sp->remain -= copy;
381 			skb->mark += copy;
382 			copied += copy;
383 			if (call->tx_total_len != -1)
384 				call->tx_total_len -= copy;
385 		}
386 
387 		/* add the packet to the send queue if it's now full */
388 		if (sp->remain <= 0 ||
389 		    (msg_data_left(msg) == 0 && !more)) {
390 			struct rxrpc_connection *conn = call->conn;
391 			uint32_t seq;
392 			size_t pad;
393 
394 			/* pad out if we're using security */
395 			if (conn->security_ix) {
396 				pad = conn->security_size + skb->mark;
397 				pad = conn->size_align - pad;
398 				pad &= conn->size_align - 1;
399 				_debug("pad %zu", pad);
400 				if (pad)
401 					skb_put_zero(skb, pad);
402 			}
403 
404 			seq = call->tx_top + 1;
405 
406 			sp->hdr.seq	= seq;
407 			sp->hdr._rsvd	= 0;
408 			sp->hdr.flags	= conn->out_clientflag;
409 
410 			if (msg_data_left(msg) == 0 && !more)
411 				sp->hdr.flags |= RXRPC_LAST_PACKET;
412 			else if (call->tx_top - call->tx_hard_ack <
413 				 call->tx_winsize)
414 				sp->hdr.flags |= RXRPC_MORE_PACKETS;
415 
416 			ret = conn->security->secure_packet(
417 				call, skb, skb->mark, skb->head);
418 			if (ret < 0)
419 				goto out;
420 
421 			rxrpc_queue_packet(rx, call, skb,
422 					   !msg_data_left(msg) && !more,
423 					   notify_end_tx);
424 			skb = NULL;
425 		}
426 
427 		/* Check for the far side aborting the call or a network error
428 		 * occurring.  If this happens, save any packet that was under
429 		 * construction so that in the case of a network error, the
430 		 * call can be retried or redirected.
431 		 */
432 		if (call->state == RXRPC_CALL_COMPLETE) {
433 			ret = call->error;
434 			goto out;
435 		}
436 	} while (msg_data_left(msg) > 0);
437 
438 success:
439 	ret = copied;
440 out:
441 	call->tx_pending = skb;
442 	_leave(" = %d", ret);
443 	return ret;
444 
445 maybe_error:
446 	if (copied)
447 		goto success;
448 	goto out;
449 
450 efault:
451 	ret = -EFAULT;
452 	goto out;
453 }
454 
455 /*
456  * extract control messages from the sendmsg() control buffer
457  */
458 static int rxrpc_sendmsg_cmsg(struct msghdr *msg, struct rxrpc_send_params *p)
459 {
460 	struct cmsghdr *cmsg;
461 	bool got_user_ID = false;
462 	int len;
463 
464 	if (msg->msg_controllen == 0)
465 		return -EINVAL;
466 
467 	for_each_cmsghdr(cmsg, msg) {
468 		if (!CMSG_OK(msg, cmsg))
469 			return -EINVAL;
470 
471 		len = cmsg->cmsg_len - sizeof(struct cmsghdr);
472 		_debug("CMSG %d, %d, %d",
473 		       cmsg->cmsg_level, cmsg->cmsg_type, len);
474 
475 		if (cmsg->cmsg_level != SOL_RXRPC)
476 			continue;
477 
478 		switch (cmsg->cmsg_type) {
479 		case RXRPC_USER_CALL_ID:
480 			if (msg->msg_flags & MSG_CMSG_COMPAT) {
481 				if (len != sizeof(u32))
482 					return -EINVAL;
483 				p->user_call_ID = *(u32 *)CMSG_DATA(cmsg);
484 			} else {
485 				if (len != sizeof(unsigned long))
486 					return -EINVAL;
487 				p->user_call_ID = *(unsigned long *)
488 					CMSG_DATA(cmsg);
489 			}
490 			got_user_ID = true;
491 			break;
492 
493 		case RXRPC_ABORT:
494 			if (p->command != RXRPC_CMD_SEND_DATA)
495 				return -EINVAL;
496 			p->command = RXRPC_CMD_SEND_ABORT;
497 			if (len != sizeof(p->abort_code))
498 				return -EINVAL;
499 			p->abort_code = *(unsigned int *)CMSG_DATA(cmsg);
500 			if (p->abort_code == 0)
501 				return -EINVAL;
502 			break;
503 
504 		case RXRPC_ACCEPT:
505 			if (p->command != RXRPC_CMD_SEND_DATA)
506 				return -EINVAL;
507 			p->command = RXRPC_CMD_ACCEPT;
508 			if (len != 0)
509 				return -EINVAL;
510 			break;
511 
512 		case RXRPC_EXCLUSIVE_CALL:
513 			p->exclusive = true;
514 			if (len != 0)
515 				return -EINVAL;
516 			break;
517 
518 		case RXRPC_UPGRADE_SERVICE:
519 			p->upgrade = true;
520 			if (len != 0)
521 				return -EINVAL;
522 			break;
523 
524 		case RXRPC_TX_LENGTH:
525 			if (p->tx_total_len != -1 || len != sizeof(__s64))
526 				return -EINVAL;
527 			p->tx_total_len = *(__s64 *)CMSG_DATA(cmsg);
528 			if (p->tx_total_len < 0)
529 				return -EINVAL;
530 			break;
531 
532 		default:
533 			return -EINVAL;
534 		}
535 	}
536 
537 	if (!got_user_ID)
538 		return -EINVAL;
539 	if (p->tx_total_len != -1 && p->command != RXRPC_CMD_SEND_DATA)
540 		return -EINVAL;
541 	_leave(" = 0");
542 	return 0;
543 }
544 
545 /*
546  * Create a new client call for sendmsg().
547  * - Called with the socket lock held, which it must release.
548  * - If it returns a call, the call's lock will need releasing by the caller.
549  */
550 static struct rxrpc_call *
551 rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
552 				  struct rxrpc_send_params *p)
553 	__releases(&rx->sk.sk_lock.slock)
554 {
555 	struct rxrpc_conn_parameters cp;
556 	struct rxrpc_call *call;
557 	struct key *key;
558 
559 	DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
560 
561 	_enter("");
562 
563 	if (!msg->msg_name) {
564 		release_sock(&rx->sk);
565 		return ERR_PTR(-EDESTADDRREQ);
566 	}
567 
568 	key = rx->key;
569 	if (key && !rx->key->payload.data[0])
570 		key = NULL;
571 
572 	memset(&cp, 0, sizeof(cp));
573 	cp.local		= rx->local;
574 	cp.key			= rx->key;
575 	cp.security_level	= rx->min_sec_level;
576 	cp.exclusive		= rx->exclusive | p->exclusive;
577 	cp.upgrade		= p->upgrade;
578 	cp.service_id		= srx->srx_service;
579 	call = rxrpc_new_client_call(rx, &cp, srx, p->user_call_ID,
580 				     p->tx_total_len, GFP_KERNEL);
581 	/* The socket is now unlocked */
582 
583 	_leave(" = %p\n", call);
584 	return call;
585 }
586 
587 /*
588  * send a message forming part of a client call through an RxRPC socket
589  * - caller holds the socket locked
590  * - the socket may be either a client socket or a server socket
591  */
592 int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
593 	__releases(&rx->sk.sk_lock.slock)
594 {
595 	enum rxrpc_call_state state;
596 	struct rxrpc_call *call;
597 	int ret;
598 
599 	struct rxrpc_send_params p = {
600 		.tx_total_len	= -1,
601 		.user_call_ID	= 0,
602 		.abort_code	= 0,
603 		.command	= RXRPC_CMD_SEND_DATA,
604 		.exclusive	= false,
605 		.upgrade	= true,
606 	};
607 
608 	_enter("");
609 
610 	ret = rxrpc_sendmsg_cmsg(msg, &p);
611 	if (ret < 0)
612 		goto error_release_sock;
613 
614 	if (p.command == RXRPC_CMD_ACCEPT) {
615 		ret = -EINVAL;
616 		if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
617 			goto error_release_sock;
618 		call = rxrpc_accept_call(rx, p.user_call_ID, NULL);
619 		/* The socket is now unlocked. */
620 		if (IS_ERR(call))
621 			return PTR_ERR(call);
622 		rxrpc_put_call(call, rxrpc_call_put);
623 		return 0;
624 	}
625 
626 	call = rxrpc_find_call_by_user_ID(rx, p.user_call_ID);
627 	if (!call) {
628 		ret = -EBADSLT;
629 		if (p.command != RXRPC_CMD_SEND_DATA)
630 			goto error_release_sock;
631 		call = rxrpc_new_client_call_for_sendmsg(rx, msg, &p);
632 		/* The socket is now unlocked... */
633 		if (IS_ERR(call))
634 			return PTR_ERR(call);
635 		/* ... and we have the call lock. */
636 	} else {
637 		switch (READ_ONCE(call->state)) {
638 		case RXRPC_CALL_UNINITIALISED:
639 		case RXRPC_CALL_CLIENT_AWAIT_CONN:
640 		case RXRPC_CALL_SERVER_PREALLOC:
641 		case RXRPC_CALL_SERVER_SECURING:
642 		case RXRPC_CALL_SERVER_ACCEPTING:
643 			ret = -EBUSY;
644 			goto error_release_sock;
645 		default:
646 			break;
647 		}
648 
649 		ret = mutex_lock_interruptible(&call->user_mutex);
650 		release_sock(&rx->sk);
651 		if (ret < 0) {
652 			ret = -ERESTARTSYS;
653 			goto error_put;
654 		}
655 
656 		if (p.tx_total_len != -1) {
657 			ret = -EINVAL;
658 			if (call->tx_total_len != -1 ||
659 			    call->tx_pending ||
660 			    call->tx_top != 0)
661 				goto error_put;
662 			call->tx_total_len = p.tx_total_len;
663 		}
664 	}
665 
666 	state = READ_ONCE(call->state);
667 	_debug("CALL %d USR %lx ST %d on CONN %p",
668 	       call->debug_id, call->user_call_ID, state, call->conn);
669 
670 	if (state >= RXRPC_CALL_COMPLETE) {
671 		/* it's too late for this call */
672 		ret = -ESHUTDOWN;
673 	} else if (p.command == RXRPC_CMD_SEND_ABORT) {
674 		ret = 0;
675 		if (rxrpc_abort_call("CMD", call, 0, p.abort_code, -ECONNABORTED))
676 			ret = rxrpc_send_abort_packet(call);
677 	} else if (p.command != RXRPC_CMD_SEND_DATA) {
678 		ret = -EINVAL;
679 	} else if (rxrpc_is_client_call(call) &&
680 		   state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
681 		/* request phase complete for this client call */
682 		ret = -EPROTO;
683 	} else if (rxrpc_is_service_call(call) &&
684 		   state != RXRPC_CALL_SERVER_ACK_REQUEST &&
685 		   state != RXRPC_CALL_SERVER_SEND_REPLY) {
686 		/* Reply phase not begun or not complete for service call. */
687 		ret = -EPROTO;
688 	} else {
689 		ret = rxrpc_send_data(rx, call, msg, len, NULL);
690 	}
691 
692 	mutex_unlock(&call->user_mutex);
693 error_put:
694 	rxrpc_put_call(call, rxrpc_call_put);
695 	_leave(" = %d", ret);
696 	return ret;
697 
698 error_release_sock:
699 	release_sock(&rx->sk);
700 	return ret;
701 }
702 
703 /**
704  * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
705  * @sock: The socket the call is on
706  * @call: The call to send data through
707  * @msg: The data to send
708  * @len: The amount of data to send
709  * @notify_end_tx: Notification that the last packet is queued.
710  *
711  * Allow a kernel service to send data on a call.  The call must be in an state
712  * appropriate to sending data.  No control data should be supplied in @msg,
713  * nor should an address be supplied.  MSG_MORE should be flagged if there's
714  * more data to come, otherwise this data will end the transmission phase.
715  */
716 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
717 			   struct msghdr *msg, size_t len,
718 			   rxrpc_notify_end_tx_t notify_end_tx)
719 {
720 	int ret;
721 
722 	_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
723 
724 	ASSERTCMP(msg->msg_name, ==, NULL);
725 	ASSERTCMP(msg->msg_control, ==, NULL);
726 
727 	mutex_lock(&call->user_mutex);
728 
729 	_debug("CALL %d USR %lx ST %d on CONN %p",
730 	       call->debug_id, call->user_call_ID, call->state, call->conn);
731 
732 	switch (READ_ONCE(call->state)) {
733 	case RXRPC_CALL_CLIENT_SEND_REQUEST:
734 	case RXRPC_CALL_SERVER_ACK_REQUEST:
735 	case RXRPC_CALL_SERVER_SEND_REPLY:
736 		ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len,
737 				      notify_end_tx);
738 		break;
739 	case RXRPC_CALL_COMPLETE:
740 		read_lock_bh(&call->state_lock);
741 		ret = call->error;
742 		read_unlock_bh(&call->state_lock);
743 		break;
744 	default:
745 		/* Request phase complete for this client call */
746 		trace_rxrpc_rx_eproto(call, 0, tracepoint_string("late_send"));
747 		ret = -EPROTO;
748 		break;
749 	}
750 
751 	mutex_unlock(&call->user_mutex);
752 	_leave(" = %d", ret);
753 	return ret;
754 }
755 EXPORT_SYMBOL(rxrpc_kernel_send_data);
756 
757 /**
758  * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
759  * @sock: The socket the call is on
760  * @call: The call to be aborted
761  * @abort_code: The abort code to stick into the ABORT packet
762  * @error: Local error value
763  * @why: 3-char string indicating why.
764  *
765  * Allow a kernel service to abort a call, if it's still in an abortable state
766  * and return true if the call was aborted, false if it was already complete.
767  */
768 bool rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
769 			     u32 abort_code, int error, const char *why)
770 {
771 	bool aborted;
772 
773 	_enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
774 
775 	mutex_lock(&call->user_mutex);
776 
777 	aborted = rxrpc_abort_call(why, call, 0, abort_code, error);
778 	if (aborted)
779 		rxrpc_send_abort_packet(call);
780 
781 	mutex_unlock(&call->user_mutex);
782 	return aborted;
783 }
784 EXPORT_SYMBOL(rxrpc_kernel_abort_call);
785 
786 /**
787  * rxrpc_kernel_set_tx_length - Set the total Tx length on a call
788  * @sock: The socket the call is on
789  * @call: The call to be informed
790  * @tx_total_len: The amount of data to be transmitted for this call
791  *
792  * Allow a kernel service to set the total transmit length on a call.  This
793  * allows buffer-to-packet encrypt-and-copy to be performed.
794  *
795  * This function is primarily for use for setting the reply length since the
796  * request length can be set when beginning the call.
797  */
798 void rxrpc_kernel_set_tx_length(struct socket *sock, struct rxrpc_call *call,
799 				s64 tx_total_len)
800 {
801 	WARN_ON(call->tx_total_len != -1);
802 	call->tx_total_len = tx_total_len;
803 }
804 EXPORT_SYMBOL(rxrpc_kernel_set_tx_length);
805