aboutsummaryrefslogtreecommitdiffstats
path: root/net/rxrpc/ar-output.c
blob: 5f22e263eda748ffdbe06f802626588a70776004 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
/* RxRPC packet transmission
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/net.h>
#include <linux/gfp.h>
#include <linux/skbuff.h>
#include <linux/circ_buf.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"

int rxrpc_resend_timeout = 4;

static int rxrpc_send_data(struct kiocb *iocb,
			   struct rxrpc_sock *rx,
			   struct rxrpc_call *call,
			   struct msghdr *msg, size_t len);

/*
 * extract control messages from the sendmsg() control buffer
 */
static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
			      unsigned long *user_call_ID,
			      enum rxrpc_command *command,
			      u32 *abort_code,
			      bool server)
{
	struct cmsghdr *cmsg;
	int len;

	*command = RXRPC_CMD_SEND_DATA;

	if (msg->msg_controllen == 0)
		return -EINVAL;

	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
		if (!CMSG_OK(msg, cmsg))
			return -EINVAL;

		len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
		_debug("CMSG %d, %d, %d",
		       cmsg->cmsg_level, cmsg->cmsg_type, len);

		if (cmsg->cmsg_level != SOL_RXRPC)
			continue;

		switch (cmsg->cmsg_type) {
		case RXRPC_USER_CALL_ID:
			if (msg->msg_flags & MSG_CMSG_COMPAT) {
				if (len != sizeof(u32))
					return -EINVAL;
				*user_call_ID = *(u32 *) CMSG_DATA(cmsg);
			} else {
				if (len != sizeof(unsigned long))
					return -EINVAL;
				*user_call_ID = *(unsigned long *)
					CMSG_DATA(cmsg);
			}
			_debug("User Call ID %lx", *user_call_ID);
			break;

		case RXRPC_ABORT:
			if (*command != RXRPC_CMD_SEND_DATA)
				return -EINVAL;
			*command = RXRPC_CMD_SEND_ABORT;
			if (len != sizeof(*abort_code))
				return -EINVAL;
			*abort_code = *(unsigned int *) CMSG_DATA(cmsg);
			_debug("Abort %x", *abort_code);
			if (*abort_code == 0)
				return -EINVAL;
			break;

		case RXRPC_ACCEPT:
			if (*command != RXRPC_CMD_SEND_DATA)
				return -EINVAL;
			*command = RXRPC_CMD_ACCEPT;
			if (len != 0)
				return -EINVAL;
			if (!server)
				return -EISCONN;
			break;

		default:
			return -EINVAL;
		}
	}

	_leave(" = 0");
	return 0;
}

/*
 * abort a call, sending an ABORT packet to the peer
 */
static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
{
	write_lock_bh(&call->state_lock);

	if (call->state <= RXRPC_CALL_COMPLETE) {
		call->state = RXRPC_CALL_LOCALLY_ABORTED;
		call->abort_code = abort_code;
		set_bit(RXRPC_CALL_ABORT, &call->events);
		del_timer_sync(&call->resend_timer);
		del_timer_sync(&call->ack_timer);
		clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
		clear_bit(RXRPC_CALL_ACK, &call->events);
		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
		rxrpc_queue_call(call);
	}

	write_unlock_bh(&call->state_lock);
}

/*
 * send a message forming part of a client call through an RxRPC socket
 * - caller holds the socket locked
 * - the socket may be either a client socket or a server socket
 */
int rxrpc_client_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
			 struct rxrpc_transport *trans, struct msghdr *msg,
			 size_t len)
{
	struct rxrpc_conn_bundle *bundle;
	enum rxrpc_command cmd;
	struct rxrpc_call *call;
	unsigned long user_call_ID = 0;
	struct key *key;
	__be16 service_id;
	u32 abort_code = 0;
	int ret;

	_enter("");

	ASSERT(trans != NULL);

	ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
				 false);
	if (ret < 0)
		return ret;

	bundle = NULL;
	if (trans) {
		service_id = rx->service_id;
		if (msg->msg_name) {
			struct sockaddr_rxrpc *srx =
				(struct sockaddr_rxrpc *) msg->msg_name;
			service_id = htons(srx->srx_service);
		}
		key = rx->key;
		if (key && !rx->key->payload.data)
			key = NULL;
		bundle = rxrpc_get_bundle(rx, trans, key, service_id,
					  GFP_KERNEL);
		if (IS_ERR(bundle))
			return PTR_ERR(bundle);
	}

	call = rxrpc_get_client_call(rx, trans, bundle, user_call_ID,
				     abort_code == 0, GFP_KERNEL);
	if (trans)
		rxrpc_put_bundle(trans, bundle);
	if (IS_ERR(call)) {
		_leave(" = %ld", PTR_ERR(call));
		return PTR_ERR(call);
	}

	_debug("CALL %d USR %lx ST %d on CONN %p",
	       call->debug_id, call->user_call_ID, call->state, call->conn);

	if (call->state >= RXRPC_CALL_COMPLETE) {
		/* it's too late for this call */
		ret = -ESHUTDOWN;
	} else if (cmd == RXRPC_CMD_SEND_ABORT) {
		rxrpc_send_abort(call, abort_code);
	} else if (cmd != RXRPC_CMD_SEND_DATA) {
		ret = -EINVAL;
	} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
		/* request phase complete for this client call */
		ret = -EPROTO;
	} else {
		ret = rxrpc_send_data(iocb, rx, call, msg, len);
	}

	rxrpc_put_call(call);
	_leave(" = %d", ret);
	return ret;
}

/**
 * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
 * @call: The call to send data through
 * @msg: The data to send
 * @len: The amount of data to send
 *
 * Allow a kernel service to send data on a call.  The call must be in an state
 * appropriate to sending data.  No control data should be supplied in @msg,
 * nor should an address be supplied.  MSG_MORE should be flagged if there's
 * more data to come, otherwise this data will end the transmission phase.
 */
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
			   size_t len)
{
	int ret;

	_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);

	ASSERTCMP(msg->msg_name, ==, NULL);
	ASSERTCMP(msg->msg_control, ==, NULL);

	lock_sock(&call->socket->sk);

	_debug("CALL %d USR %lx ST %d on CONN %p",
	       call->debug_id, call->user_call_ID, call->state, call->conn);

	if (call->state >= RXRPC_CALL_COMPLETE) {
		ret = -ESHUTDOWN; /* it's too late for this call */
	} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
		ret = -EPROTO; /* request phase complete for this client call */
	} else {
		mm_segment_t oldfs = get_fs();
		set_fs(KERNEL_DS);
		ret = rxrpc_send_data(NULL, call->socket, call, msg, len);
		set_fs(oldfs);
	}

	release_sock(&call->socket->sk);
	_leave(" = %d", ret);
	return ret;
}

EXPORT_SYMBOL(rxrpc_kernel_send_data);

/*
 * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
 * @call: The call to be aborted
 * @abort_code: The abort code to stick into the ABORT packet
 *
 * Allow a kernel service to abort a call, if it's still in an abortable state.
 */
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code)
{
	_enter("{%d},%d", call->debug_id, abort_code);

	lock_sock(&call->socket->sk);

	_debug("CALL %d USR %lx ST %d on CONN %p",
	       call->debug_id, call->user_call_ID, call->state, call->conn);

	if (call->state < RXRPC_CALL_COMPLETE)
		rxrpc_send_abort(call, abort_code);

	release_sock(&call->socket->sk);
	_leave("");
}

EXPORT_SYMBOL(rxrpc_kernel_abort_call);

/*
 * send a message through a server socket
 * - caller holds the socket locked
 */
int rxrpc_server_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
			 struct msghdr *msg, size_t len)
{
	enum rxrpc_command cmd;
	struct rxrpc_call *call;
	unsigned long user_call_ID = 0;
	u32 abort_code = 0;
	int ret;

	_enter("");

	ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
				 true);
	if (ret < 0)
		return ret;

	if (cmd == RXRPC_CMD_ACCEPT) {
		call = rxrpc_accept_call(rx, user_call_ID);
		if (IS_ERR(call))
			return PTR_ERR(call);
		rxrpc_put_call(call);
		return 0;
	}

	call = rxrpc_find_server_call(rx, user_call_ID);
	if (!call)
		return -EBADSLT;
	if (call->state >= RXRPC_CALL_COMPLETE) {
		ret = -ESHUTDOWN;
		goto out;
	}

	switch (cmd) {
	case RXRPC_CMD_SEND_DATA:
		if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
		    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
		    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
			/* Tx phase not yet begun for this call */
			ret = -EPROTO;
			break;
		}

		ret = rxrpc_send_data(iocb, rx, call, msg, len);
		break;

	case RXRPC_CMD_SEND_ABORT:
		rxrpc_send_abort(call, abort_code);
		break;
	default:
		BUG();
	}

	out:
	rxrpc_put_call(call);
	_leave(" = %d", ret);
	return ret;
}

/*
 * send a packet through the transport endpoint
 */
int rxrpc_send_packet(struct rxrpc_transport *trans, struct sk_buff *skb)
{
	struct kvec iov[1];
	struct msghdr msg;
	int ret, opt;

	_enter(",{%d}", skb->len);

	iov[0].iov_base = skb->head;
	iov[0].iov_len = skb->len;

	msg.msg_name = &trans->peer->srx.transport.sin;
	msg.msg_namelen = sizeof(trans->peer->srx.transport.sin);
	msg.msg_control = NULL;
	msg.msg_controllen = 0;
	msg.msg_flags = 0;

	/* send the packet with the don't fragment bit set if we currently
	 * think it's small enough */
	if (skb->len - sizeof(struct rxrpc_header) < trans->peer->maxdata) {
		down_read(&trans->local->defrag_sem);
		/* send the packet by UDP
		 * - returns -EMSGSIZE if UDP would have to fragment the packet
		 *   to go out of the interface
		 *   - in which case, we'll have processed the ICMP error
		 *     message and update the peer record
		 */
		ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
				     iov[0].iov_len);

		up_read(&trans->local->defrag_sem);
		if (ret == -EMSGSIZE)
			goto send_fragmentable;

		_leave(" = %d [%u]", ret, trans->peer->maxdata);
		return ret;
	}

send_fragmentable:
	/* attempt to send this message with fragmentation enabled */
	_debug("send fragment");

	down_write(&trans->local->defrag_sem);
	opt = IP_PMTUDISC_DONT;
	ret = kernel_setsockopt(trans->local->socket, SOL_IP, IP_MTU_DISCOVER,
				(char *) &opt, sizeof(opt));
	if (ret == 0) {
		ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
				     iov[0].iov_len);

		opt = IP_PMTUDISC_DO;
		kernel_setsockopt(trans->local->socket, SOL_IP,
				  IP_MTU_DISCOVER, (char *) &opt, sizeof(opt));
	}

	up_write(&trans->local->defrag_sem);
	_leave(" = %d [frag %u]", ret, trans->peer->maxdata);
	return ret;
}

/*
 * wait for space to appear in the transmit/ACK window
 * - caller holds the socket locked
 */
static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
				    struct rxrpc_call *call,
				    long *timeo)
{
	DECLARE_WAITQUEUE(myself, current);
	int ret;

	_enter(",{%d},%ld",
	       CIRC_SPACE(call->acks_head, call->acks_tail, call->acks_winsz),
	       *timeo);

	add_wait_queue(&call->tx_waitq, &myself);

	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);
		ret = 0;
		if (CIRC_SPACE(call->acks_head, call->acks_tail,
			       call->acks_winsz) > 0)
			break;
		if (signal_pending(current)) {
			ret = sock_intr_errno(*timeo);
			break;
		}

		release_sock(&rx->sk);
		*timeo = schedule_timeout(*timeo);
		lock_sock(&rx->sk);
	}

	remove_wait_queue(&call->tx_waitq, &myself);
	set_current_state(TASK_RUNNING);
	_leave(" = %d", ret);
	return ret;
}

/*
 * attempt to schedule an instant Tx resend
 */
static inline void rxrpc_instant_resend(struct rxrpc_call *call)
{
	read_lock_bh(&call->state_lock);
	if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
		if (call->state < RXRPC_CALL_COMPLETE &&
		    !test_and_set_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
			rxrpc_queue_call(call);
	}
	read_unlock_bh(&call->state_lock);
}

/*
 * queue a packet for transmission, set the resend timer and attempt
 * to send the packet immediately
 */
static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
			       bool last)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	int ret;

	_net("queue skb %p [%d]", skb, call->acks_head);

	ASSERT(call->acks_window != NULL);
	call->acks_window[call->acks_head] = (unsigned long) skb;
	smp_wmb();
	call->acks_head = (call->acks_head + 1) & (call->acks_winsz - 1);

	if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
		_debug("________awaiting reply/ACK__________");
		write_lock_bh(&call->state_lock);
		switch (call->state) {
		case RXRPC_CALL_CLIENT_SEND_REQUEST:
			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
			break;
		case RXRPC_CALL_SERVER_ACK_REQUEST:
			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
			if (!last)
				break;
		case RXRPC_CALL_SERVER_SEND_REPLY:
			call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
			break;
		default:
			break;
		}
		write_unlock_bh(&call->state_lock);
	}

	_proto("Tx DATA %%%u { #%u }",
	       ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));

	sp->need_resend = 0;
	sp->resend_at = jiffies + rxrpc_resend_timeout * HZ;
	if (!test_and_set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags)) {
		_debug("run timer");
		call->resend_timer.expires = sp->resend_at;
		add_timer(&call->resend_timer);
	}

	/* attempt to cancel the rx-ACK timer, deferring reply transmission if
	 * we're ACK'ing the request phase of an incoming call */
	ret = -EAGAIN;
	if (try_to_del_timer_sync(&call->ack_timer) >= 0) {
		/* the packet may be freed by rxrpc_process_call() before this
		 * returns */
		ret = rxrpc_send_packet(call->conn->trans, skb);
		_net("sent skb %p", skb);
	} else {
		_debug("failed to delete ACK timer");
	}

	if (ret < 0) {
		_debug("need instant resend %d", ret);
		sp->need_resend = 1;
		rxrpc_instant_resend(call);
	}

	_leave("");
}

/*
 * send data through a socket
 * - must be called in process context
 * - caller holds the socket locked
 */
static int rxrpc_send_data(struct kiocb *iocb,
			   struct rxrpc_sock *rx,
			   struct rxrpc_call *call,
			   struct msghdr *msg, size_t len)
{
	struct rxrpc_skb_priv *sp;
	unsigned char __user *from;
	struct sk_buff *skb;
	struct iovec *iov;
	struct sock *sk = &rx->sk;
	long timeo;
	bool more;
	int ret, ioc, segment, copied;

	_enter(",,,{%zu},%zu", msg->msg_iovlen, len);

	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);

	/* this should be in poll */
	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
		return -EPIPE;

	iov = msg->msg_iov;
	ioc = msg->msg_iovlen - 1;
	from = iov->iov_base;
	segment = iov->iov_len;
	iov++;
	more = msg->msg_flags & MSG_MORE;

	skb = call->tx_pending;
	call->tx_pending = NULL;

	copied = 0;
	do {
		int copy;

		if (segment > len)
			segment = len;

		_debug("SEGMENT %d @%p", segment, from);

		if (!skb) {
			size_t size, chunk, max, space;

			_debug("alloc");

			if (CIRC_SPACE(call->acks_head, call->acks_tail,
				       call->acks_winsz) <= 0) {
				ret = -EAGAIN;
				if (msg->msg_flags & MSG_DONTWAIT)
					goto maybe_error;
				ret = rxrpc_wait_for_tx_window(rx, call,
							       &timeo);
				if (ret < 0)
					goto maybe_error;
			}

			max = call->conn->trans->peer->maxdata;
			max -= call->conn->security_size;
			max &= ~(call->conn->size_align - 1UL);

			chunk = max;
			if (chunk > len && !more)
				chunk = len;

			space = chunk + call->conn->size_align;
			space &= ~(call->conn->size_align - 1UL);

			size = space + call->conn->header_size;

			_debug("SIZE: %zu/%zu/%zu", chunk, space, size);

			/* create a buffer that we can retain until it's ACK'd */
			skb = sock_alloc_send_skb(
				sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
			if (!skb)
				goto maybe_error;

			rxrpc_new_skb(skb);

			_debug("ALLOC SEND %p", skb);

			ASSERTCMP(skb->mark, ==, 0);

			_debug("HS: %u", call->conn->header_size);
			skb_reserve(skb, call->conn->header_size);
			skb->len += call->conn->header_size;

			sp = rxrpc_skb(skb);
			sp->remain = chunk;
			if (sp->remain > skb_tailroom(skb))
				sp->remain = skb_tailroom(skb);

			_net("skb: hr %d, tr %d, hl %d, rm %d",
			       skb_headroom(skb),
			       skb_tailroom(skb),
			       skb_headlen(skb),
			       sp->remain);

			skb->ip_summed = CHECKSUM_UNNECESSARY;
		}

		_debug("append");
		sp = rxrpc_skb(skb);

		/* append next segment of data to the current buffer */
		copy = skb_tailroom(skb);
		ASSERTCMP(copy, >, 0);
		if (copy > segment)
			copy = segment;
		if (copy > sp->remain)
			copy = sp->remain;

		_debug("add");
		ret = skb_add_data(skb, from, copy);
		_debug("added");
		if (ret < 0)
			goto efault;
		sp->remain -= copy;
		skb->mark += copy;
		copied += copy;

		len -= copy;
		segment -= copy;
		from += copy;
		while (segment == 0 && ioc > 0) {
			from = iov->iov_base;
			segment = iov->iov_len;
			iov++;
			ioc--;
		}
		if (len == 0) {
			segment = 0;
			ioc = 0;
		}

		/* check for the far side aborting the call or a network error
		 * occurring */
		if (call->state > RXRPC_CALL_COMPLETE)
			goto call_aborted;

		/* add the packet to the send queue if it's now full */
		if (sp->remain <= 0 || (segment == 0 && !more)) {
			struct rxrpc_connection *conn = call->conn;
			size_t pad;

			/* pad out if we're using security */
			if (conn->security) {
				pad = conn->security_size + skb->mark;
				pad = conn->size_align - pad;
				pad &= conn->size_align - 1;
				_debug("pad %zu", pad);
				if (pad)
					memset(skb_put(skb, pad), 0, pad);
			}

			sp->hdr.epoch = conn->epoch;
			sp->hdr.cid = call->cid;
			sp->hdr.callNumber = call->call_id;
			sp->hdr.seq =
				htonl(atomic_inc_return(&call->sequence));
			sp->hdr.serial =
				htonl(atomic_inc_return(&conn->serial));
			sp->hdr.type = RXRPC_PACKET_TYPE_DATA;
			sp->hdr.userStatus = 0;
			sp->hdr.securityIndex = conn->security_ix;
			sp->hdr._rsvd = 0;
			sp->hdr.serviceId = conn->service_id;

			sp->hdr.flags = conn->out_clientflag;
			if (len == 0 && !more)
				sp->hdr.flags |= RXRPC_LAST_PACKET;
			else if (CIRC_SPACE(call->acks_head, call->acks_tail,
					    call->acks_winsz) > 1)
				sp->hdr.flags |= RXRPC_MORE_PACKETS;

			ret = rxrpc_secure_packet(
				call, skb, skb->mark,
				skb->head + sizeof(struct rxrpc_header));
			if (ret < 0)
				goto out;

			memcpy(skb->head, &sp->hdr,
			       sizeof(struct rxrpc_header));
			rxrpc_queue_packet(call, skb, segment == 0 && !more);
			skb = NULL;
		}

	} while (segment > 0);

success:
	ret = copied;
out:
	call->tx_pending = skb;
	_leave(" = %d", ret);
	return ret;

call_aborted:
	rxrpc_free_skb(skb);
	if (call->state == RXRPC_CALL_NETWORK_ERROR)
		ret = call->conn->trans->peer->net_error;
	else
		ret = -ECONNABORTED;
	_leave(" = %d", ret);
	return ret;

maybe_error:
	if (copied)
		goto success;
	goto out;

efault:
	ret = -EFAULT;
	goto out;
}