xref: /linux/net/rxrpc/output.c (revision 071bf69a0220253a44acb8b2a27f7a262b9a46bf)
1 /* RxRPC packet transmission
2  *
3  * Copyright (C) 2007 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 License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, 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/circ_buf.h>
18 #include <linux/export.h>
19 #include <net/sock.h>
20 #include <net/af_rxrpc.h>
21 #include "ar-internal.h"
22 
23 /*
24  * Time till packet resend (in jiffies).
25  */
26 unsigned int rxrpc_resend_timeout = 4 * HZ;
27 
28 static int rxrpc_send_data(struct rxrpc_sock *rx,
29 			   struct rxrpc_call *call,
30 			   struct msghdr *msg, size_t len);
31 
32 /*
33  * extract control messages from the sendmsg() control buffer
34  */
35 static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
36 			      unsigned long *user_call_ID,
37 			      enum rxrpc_command *command,
38 			      u32 *abort_code,
39 			      bool *_exclusive)
40 {
41 	struct cmsghdr *cmsg;
42 	bool got_user_ID = false;
43 	int len;
44 
45 	*command = RXRPC_CMD_SEND_DATA;
46 
47 	if (msg->msg_controllen == 0)
48 		return -EINVAL;
49 
50 	for_each_cmsghdr(cmsg, msg) {
51 		if (!CMSG_OK(msg, cmsg))
52 			return -EINVAL;
53 
54 		len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
55 		_debug("CMSG %d, %d, %d",
56 		       cmsg->cmsg_level, cmsg->cmsg_type, len);
57 
58 		if (cmsg->cmsg_level != SOL_RXRPC)
59 			continue;
60 
61 		switch (cmsg->cmsg_type) {
62 		case RXRPC_USER_CALL_ID:
63 			if (msg->msg_flags & MSG_CMSG_COMPAT) {
64 				if (len != sizeof(u32))
65 					return -EINVAL;
66 				*user_call_ID = *(u32 *) CMSG_DATA(cmsg);
67 			} else {
68 				if (len != sizeof(unsigned long))
69 					return -EINVAL;
70 				*user_call_ID = *(unsigned long *)
71 					CMSG_DATA(cmsg);
72 			}
73 			_debug("User Call ID %lx", *user_call_ID);
74 			got_user_ID = true;
75 			break;
76 
77 		case RXRPC_ABORT:
78 			if (*command != RXRPC_CMD_SEND_DATA)
79 				return -EINVAL;
80 			*command = RXRPC_CMD_SEND_ABORT;
81 			if (len != sizeof(*abort_code))
82 				return -EINVAL;
83 			*abort_code = *(unsigned int *) CMSG_DATA(cmsg);
84 			_debug("Abort %x", *abort_code);
85 			if (*abort_code == 0)
86 				return -EINVAL;
87 			break;
88 
89 		case RXRPC_ACCEPT:
90 			if (*command != RXRPC_CMD_SEND_DATA)
91 				return -EINVAL;
92 			*command = RXRPC_CMD_ACCEPT;
93 			if (len != 0)
94 				return -EINVAL;
95 			break;
96 
97 		case RXRPC_EXCLUSIVE_CALL:
98 			*_exclusive = true;
99 			if (len != 0)
100 				return -EINVAL;
101 			break;
102 		default:
103 			return -EINVAL;
104 		}
105 	}
106 
107 	if (!got_user_ID)
108 		return -EINVAL;
109 	_leave(" = 0");
110 	return 0;
111 }
112 
113 /*
114  * abort a call, sending an ABORT packet to the peer
115  */
116 static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
117 {
118 	write_lock_bh(&call->state_lock);
119 
120 	if (call->state <= RXRPC_CALL_COMPLETE) {
121 		call->state = RXRPC_CALL_LOCALLY_ABORTED;
122 		call->local_abort = abort_code;
123 		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
124 		del_timer_sync(&call->resend_timer);
125 		del_timer_sync(&call->ack_timer);
126 		clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
127 		clear_bit(RXRPC_CALL_EV_ACK, &call->events);
128 		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
129 		rxrpc_queue_call(call);
130 	}
131 
132 	write_unlock_bh(&call->state_lock);
133 }
134 
135 /*
136  * Create a new client call for sendmsg().
137  */
138 static struct rxrpc_call *
139 rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
140 				  unsigned long user_call_ID, bool exclusive)
141 {
142 	struct rxrpc_conn_parameters cp;
143 	struct rxrpc_call *call;
144 	struct key *key;
145 
146 	DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
147 
148 	_enter("");
149 
150 	if (!msg->msg_name)
151 		return ERR_PTR(-EDESTADDRREQ);
152 
153 	key = rx->key;
154 	if (key && !rx->key->payload.data[0])
155 		key = NULL;
156 
157 	memset(&cp, 0, sizeof(cp));
158 	cp.local		= rx->local;
159 	cp.key			= rx->key;
160 	cp.security_level	= rx->min_sec_level;
161 	cp.exclusive		= rx->exclusive | exclusive;
162 	cp.service_id		= srx->srx_service;
163 	call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
164 
165 	_leave(" = %p\n", call);
166 	return call;
167 }
168 
169 /*
170  * send a message forming part of a client call through an RxRPC socket
171  * - caller holds the socket locked
172  * - the socket may be either a client socket or a server socket
173  */
174 int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
175 {
176 	enum rxrpc_command cmd;
177 	struct rxrpc_call *call;
178 	unsigned long user_call_ID = 0;
179 	bool exclusive = false;
180 	u32 abort_code = 0;
181 	int ret;
182 
183 	_enter("");
184 
185 	ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
186 				 &exclusive);
187 	if (ret < 0)
188 		return ret;
189 
190 	if (cmd == RXRPC_CMD_ACCEPT) {
191 		if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
192 			return -EINVAL;
193 		call = rxrpc_accept_call(rx, user_call_ID);
194 		if (IS_ERR(call))
195 			return PTR_ERR(call);
196 		rxrpc_put_call(call);
197 		return 0;
198 	}
199 
200 	call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
201 	if (!call) {
202 		if (cmd != RXRPC_CMD_SEND_DATA)
203 			return -EBADSLT;
204 		call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
205 							 exclusive);
206 		if (IS_ERR(call))
207 			return PTR_ERR(call);
208 	}
209 
210 	_debug("CALL %d USR %lx ST %d on CONN %p",
211 	       call->debug_id, call->user_call_ID, call->state, call->conn);
212 
213 	if (call->state >= RXRPC_CALL_COMPLETE) {
214 		/* it's too late for this call */
215 		ret = -ECONNRESET;
216 	} else if (cmd == RXRPC_CMD_SEND_ABORT) {
217 		rxrpc_send_abort(call, abort_code);
218 		ret = 0;
219 	} else if (cmd != RXRPC_CMD_SEND_DATA) {
220 		ret = -EINVAL;
221 	} else if (!call->in_clientflag &&
222 		   call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
223 		/* request phase complete for this client call */
224 		ret = -EPROTO;
225 	} else if (call->in_clientflag &&
226 		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
227 		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
228 		/* Reply phase not begun or not complete for service call. */
229 		ret = -EPROTO;
230 	} else {
231 		ret = rxrpc_send_data(rx, call, msg, len);
232 	}
233 
234 	rxrpc_put_call(call);
235 	_leave(" = %d", ret);
236 	return ret;
237 }
238 
239 /**
240  * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
241  * @call: The call to send data through
242  * @msg: The data to send
243  * @len: The amount of data to send
244  *
245  * Allow a kernel service to send data on a call.  The call must be in an state
246  * appropriate to sending data.  No control data should be supplied in @msg,
247  * nor should an address be supplied.  MSG_MORE should be flagged if there's
248  * more data to come, otherwise this data will end the transmission phase.
249  */
250 int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
251 			   size_t len)
252 {
253 	int ret;
254 
255 	_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
256 
257 	ASSERTCMP(msg->msg_name, ==, NULL);
258 	ASSERTCMP(msg->msg_control, ==, NULL);
259 
260 	lock_sock(&call->socket->sk);
261 
262 	_debug("CALL %d USR %lx ST %d on CONN %p",
263 	       call->debug_id, call->user_call_ID, call->state, call->conn);
264 
265 	if (call->state >= RXRPC_CALL_COMPLETE) {
266 		ret = -ESHUTDOWN; /* it's too late for this call */
267 	} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
268 		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
269 		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
270 		ret = -EPROTO; /* request phase complete for this client call */
271 	} else {
272 		ret = rxrpc_send_data(call->socket, call, msg, len);
273 	}
274 
275 	release_sock(&call->socket->sk);
276 	_leave(" = %d", ret);
277 	return ret;
278 }
279 
280 EXPORT_SYMBOL(rxrpc_kernel_send_data);
281 
282 /**
283  * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
284  * @call: The call to be aborted
285  * @abort_code: The abort code to stick into the ABORT packet
286  *
287  * Allow a kernel service to abort a call, if it's still in an abortable state.
288  */
289 void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code)
290 {
291 	_enter("{%d},%d", call->debug_id, abort_code);
292 
293 	lock_sock(&call->socket->sk);
294 
295 	_debug("CALL %d USR %lx ST %d on CONN %p",
296 	       call->debug_id, call->user_call_ID, call->state, call->conn);
297 
298 	if (call->state < RXRPC_CALL_COMPLETE)
299 		rxrpc_send_abort(call, abort_code);
300 
301 	release_sock(&call->socket->sk);
302 	_leave("");
303 }
304 
305 EXPORT_SYMBOL(rxrpc_kernel_abort_call);
306 
307 /*
308  * send a packet through the transport endpoint
309  */
310 int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
311 {
312 	struct kvec iov[1];
313 	struct msghdr msg;
314 	int ret, opt;
315 
316 	_enter(",{%d}", skb->len);
317 
318 	iov[0].iov_base = skb->head;
319 	iov[0].iov_len = skb->len;
320 
321 	msg.msg_name = &conn->params.peer->srx.transport;
322 	msg.msg_namelen = conn->params.peer->srx.transport_len;
323 	msg.msg_control = NULL;
324 	msg.msg_controllen = 0;
325 	msg.msg_flags = 0;
326 
327 	/* send the packet with the don't fragment bit set if we currently
328 	 * think it's small enough */
329 	if (skb->len - sizeof(struct rxrpc_wire_header) < conn->params.peer->maxdata) {
330 		down_read(&conn->params.local->defrag_sem);
331 		/* send the packet by UDP
332 		 * - returns -EMSGSIZE if UDP would have to fragment the packet
333 		 *   to go out of the interface
334 		 *   - in which case, we'll have processed the ICMP error
335 		 *     message and update the peer record
336 		 */
337 		ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
338 				     iov[0].iov_len);
339 
340 		up_read(&conn->params.local->defrag_sem);
341 		if (ret == -EMSGSIZE)
342 			goto send_fragmentable;
343 
344 		_leave(" = %d [%u]", ret, conn->params.peer->maxdata);
345 		return ret;
346 	}
347 
348 send_fragmentable:
349 	/* attempt to send this message with fragmentation enabled */
350 	_debug("send fragment");
351 
352 	down_write(&conn->params.local->defrag_sem);
353 
354 	switch (conn->params.local->srx.transport.family) {
355 	case AF_INET:
356 		opt = IP_PMTUDISC_DONT;
357 		ret = kernel_setsockopt(conn->params.local->socket,
358 					SOL_IP, IP_MTU_DISCOVER,
359 					(char *)&opt, sizeof(opt));
360 		if (ret == 0) {
361 			ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
362 					     iov[0].iov_len);
363 
364 			opt = IP_PMTUDISC_DO;
365 			kernel_setsockopt(conn->params.local->socket, SOL_IP,
366 					  IP_MTU_DISCOVER,
367 					  (char *)&opt, sizeof(opt));
368 		}
369 		break;
370 	}
371 
372 	up_write(&conn->params.local->defrag_sem);
373 	_leave(" = %d [frag %u]", ret, conn->params.peer->maxdata);
374 	return ret;
375 }
376 
377 /*
378  * wait for space to appear in the transmit/ACK window
379  * - caller holds the socket locked
380  */
381 static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
382 				    struct rxrpc_call *call,
383 				    long *timeo)
384 {
385 	DECLARE_WAITQUEUE(myself, current);
386 	int ret;
387 
388 	_enter(",{%d},%ld",
389 	       CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
390 			  call->acks_winsz),
391 	       *timeo);
392 
393 	add_wait_queue(&call->tx_waitq, &myself);
394 
395 	for (;;) {
396 		set_current_state(TASK_INTERRUPTIBLE);
397 		ret = 0;
398 		if (CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
399 			       call->acks_winsz) > 0)
400 			break;
401 		if (signal_pending(current)) {
402 			ret = sock_intr_errno(*timeo);
403 			break;
404 		}
405 
406 		release_sock(&rx->sk);
407 		*timeo = schedule_timeout(*timeo);
408 		lock_sock(&rx->sk);
409 	}
410 
411 	remove_wait_queue(&call->tx_waitq, &myself);
412 	set_current_state(TASK_RUNNING);
413 	_leave(" = %d", ret);
414 	return ret;
415 }
416 
417 /*
418  * attempt to schedule an instant Tx resend
419  */
420 static inline void rxrpc_instant_resend(struct rxrpc_call *call)
421 {
422 	read_lock_bh(&call->state_lock);
423 	if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
424 		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
425 		if (call->state < RXRPC_CALL_COMPLETE &&
426 		    !test_and_set_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events))
427 			rxrpc_queue_call(call);
428 	}
429 	read_unlock_bh(&call->state_lock);
430 }
431 
432 /*
433  * queue a packet for transmission, set the resend timer and attempt
434  * to send the packet immediately
435  */
436 static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
437 			       bool last)
438 {
439 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
440 	int ret;
441 
442 	_net("queue skb %p [%d]", skb, call->acks_head);
443 
444 	ASSERT(call->acks_window != NULL);
445 	call->acks_window[call->acks_head] = (unsigned long) skb;
446 	smp_wmb();
447 	call->acks_head = (call->acks_head + 1) & (call->acks_winsz - 1);
448 
449 	if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
450 		_debug("________awaiting reply/ACK__________");
451 		write_lock_bh(&call->state_lock);
452 		switch (call->state) {
453 		case RXRPC_CALL_CLIENT_SEND_REQUEST:
454 			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
455 			break;
456 		case RXRPC_CALL_SERVER_ACK_REQUEST:
457 			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
458 			if (!last)
459 				break;
460 		case RXRPC_CALL_SERVER_SEND_REPLY:
461 			call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
462 			break;
463 		default:
464 			break;
465 		}
466 		write_unlock_bh(&call->state_lock);
467 	}
468 
469 	_proto("Tx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
470 
471 	sp->need_resend = false;
472 	sp->resend_at = jiffies + rxrpc_resend_timeout;
473 	if (!test_and_set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags)) {
474 		_debug("run timer");
475 		call->resend_timer.expires = sp->resend_at;
476 		add_timer(&call->resend_timer);
477 	}
478 
479 	/* attempt to cancel the rx-ACK timer, deferring reply transmission if
480 	 * we're ACK'ing the request phase of an incoming call */
481 	ret = -EAGAIN;
482 	if (try_to_del_timer_sync(&call->ack_timer) >= 0) {
483 		/* the packet may be freed by rxrpc_process_call() before this
484 		 * returns */
485 		ret = rxrpc_send_data_packet(call->conn, skb);
486 		_net("sent skb %p", skb);
487 	} else {
488 		_debug("failed to delete ACK timer");
489 	}
490 
491 	if (ret < 0) {
492 		_debug("need instant resend %d", ret);
493 		sp->need_resend = true;
494 		rxrpc_instant_resend(call);
495 	}
496 
497 	_leave("");
498 }
499 
500 /*
501  * Convert a host-endian header into a network-endian header.
502  */
503 static void rxrpc_insert_header(struct sk_buff *skb)
504 {
505 	struct rxrpc_wire_header whdr;
506 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
507 
508 	whdr.epoch	= htonl(sp->hdr.epoch);
509 	whdr.cid	= htonl(sp->hdr.cid);
510 	whdr.callNumber	= htonl(sp->hdr.callNumber);
511 	whdr.seq	= htonl(sp->hdr.seq);
512 	whdr.serial	= htonl(sp->hdr.serial);
513 	whdr.type	= sp->hdr.type;
514 	whdr.flags	= sp->hdr.flags;
515 	whdr.userStatus	= sp->hdr.userStatus;
516 	whdr.securityIndex = sp->hdr.securityIndex;
517 	whdr._rsvd	= htons(sp->hdr._rsvd);
518 	whdr.serviceId	= htons(sp->hdr.serviceId);
519 
520 	memcpy(skb->head, &whdr, sizeof(whdr));
521 }
522 
523 /*
524  * send data through a socket
525  * - must be called in process context
526  * - caller holds the socket locked
527  */
528 static int rxrpc_send_data(struct rxrpc_sock *rx,
529 			   struct rxrpc_call *call,
530 			   struct msghdr *msg, size_t len)
531 {
532 	struct rxrpc_skb_priv *sp;
533 	struct sk_buff *skb;
534 	struct sock *sk = &rx->sk;
535 	long timeo;
536 	bool more;
537 	int ret, copied;
538 
539 	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
540 
541 	/* this should be in poll */
542 	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
543 
544 	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
545 		return -EPIPE;
546 
547 	more = msg->msg_flags & MSG_MORE;
548 
549 	skb = call->tx_pending;
550 	call->tx_pending = NULL;
551 
552 	copied = 0;
553 	do {
554 		if (!skb) {
555 			size_t size, chunk, max, space;
556 
557 			_debug("alloc");
558 
559 			if (CIRC_SPACE(call->acks_head,
560 				       ACCESS_ONCE(call->acks_tail),
561 				       call->acks_winsz) <= 0) {
562 				ret = -EAGAIN;
563 				if (msg->msg_flags & MSG_DONTWAIT)
564 					goto maybe_error;
565 				ret = rxrpc_wait_for_tx_window(rx, call,
566 							       &timeo);
567 				if (ret < 0)
568 					goto maybe_error;
569 			}
570 
571 			max = call->conn->params.peer->maxdata;
572 			max -= call->conn->security_size;
573 			max &= ~(call->conn->size_align - 1UL);
574 
575 			chunk = max;
576 			if (chunk > msg_data_left(msg) && !more)
577 				chunk = msg_data_left(msg);
578 
579 			space = chunk + call->conn->size_align;
580 			space &= ~(call->conn->size_align - 1UL);
581 
582 			size = space + call->conn->header_size;
583 
584 			_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
585 
586 			/* create a buffer that we can retain until it's ACK'd */
587 			skb = sock_alloc_send_skb(
588 				sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
589 			if (!skb)
590 				goto maybe_error;
591 
592 			rxrpc_new_skb(skb);
593 
594 			_debug("ALLOC SEND %p", skb);
595 
596 			ASSERTCMP(skb->mark, ==, 0);
597 
598 			_debug("HS: %u", call->conn->header_size);
599 			skb_reserve(skb, call->conn->header_size);
600 			skb->len += call->conn->header_size;
601 
602 			sp = rxrpc_skb(skb);
603 			sp->remain = chunk;
604 			if (sp->remain > skb_tailroom(skb))
605 				sp->remain = skb_tailroom(skb);
606 
607 			_net("skb: hr %d, tr %d, hl %d, rm %d",
608 			       skb_headroom(skb),
609 			       skb_tailroom(skb),
610 			       skb_headlen(skb),
611 			       sp->remain);
612 
613 			skb->ip_summed = CHECKSUM_UNNECESSARY;
614 		}
615 
616 		_debug("append");
617 		sp = rxrpc_skb(skb);
618 
619 		/* append next segment of data to the current buffer */
620 		if (msg_data_left(msg) > 0) {
621 			int copy = skb_tailroom(skb);
622 			ASSERTCMP(copy, >, 0);
623 			if (copy > msg_data_left(msg))
624 				copy = msg_data_left(msg);
625 			if (copy > sp->remain)
626 				copy = sp->remain;
627 
628 			_debug("add");
629 			ret = skb_add_data(skb, &msg->msg_iter, copy);
630 			_debug("added");
631 			if (ret < 0)
632 				goto efault;
633 			sp->remain -= copy;
634 			skb->mark += copy;
635 			copied += copy;
636 		}
637 
638 		/* check for the far side aborting the call or a network error
639 		 * occurring */
640 		if (call->state > RXRPC_CALL_COMPLETE)
641 			goto call_aborted;
642 
643 		/* add the packet to the send queue if it's now full */
644 		if (sp->remain <= 0 ||
645 		    (msg_data_left(msg) == 0 && !more)) {
646 			struct rxrpc_connection *conn = call->conn;
647 			uint32_t seq;
648 			size_t pad;
649 
650 			/* pad out if we're using security */
651 			if (conn->security_ix) {
652 				pad = conn->security_size + skb->mark;
653 				pad = conn->size_align - pad;
654 				pad &= conn->size_align - 1;
655 				_debug("pad %zu", pad);
656 				if (pad)
657 					memset(skb_put(skb, pad), 0, pad);
658 			}
659 
660 			seq = atomic_inc_return(&call->sequence);
661 
662 			sp->hdr.epoch	= conn->proto.epoch;
663 			sp->hdr.cid	= call->cid;
664 			sp->hdr.callNumber = call->call_id;
665 			sp->hdr.seq	= seq;
666 			sp->hdr.serial	= atomic_inc_return(&conn->serial);
667 			sp->hdr.type	= RXRPC_PACKET_TYPE_DATA;
668 			sp->hdr.userStatus = 0;
669 			sp->hdr.securityIndex = conn->security_ix;
670 			sp->hdr._rsvd	= 0;
671 			sp->hdr.serviceId = call->service_id;
672 
673 			sp->hdr.flags = conn->out_clientflag;
674 			if (msg_data_left(msg) == 0 && !more)
675 				sp->hdr.flags |= RXRPC_LAST_PACKET;
676 			else if (CIRC_SPACE(call->acks_head,
677 					    ACCESS_ONCE(call->acks_tail),
678 					    call->acks_winsz) > 1)
679 				sp->hdr.flags |= RXRPC_MORE_PACKETS;
680 			if (more && seq & 1)
681 				sp->hdr.flags |= RXRPC_REQUEST_ACK;
682 
683 			ret = conn->security->secure_packet(
684 				call, skb, skb->mark,
685 				skb->head + sizeof(struct rxrpc_wire_header));
686 			if (ret < 0)
687 				goto out;
688 
689 			rxrpc_insert_header(skb);
690 			rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
691 			skb = NULL;
692 		}
693 	} while (msg_data_left(msg) > 0);
694 
695 success:
696 	ret = copied;
697 out:
698 	call->tx_pending = skb;
699 	_leave(" = %d", ret);
700 	return ret;
701 
702 call_aborted:
703 	rxrpc_free_skb(skb);
704 	if (call->state == RXRPC_CALL_NETWORK_ERROR)
705 		ret = call->error_report < RXRPC_LOCAL_ERROR_OFFSET ?
706 			call->error_report :
707 			call->error_report - RXRPC_LOCAL_ERROR_OFFSET;
708 	else
709 		ret = -ECONNABORTED;
710 	_leave(" = %d", ret);
711 	return ret;
712 
713 maybe_error:
714 	if (copied)
715 		goto success;
716 	goto out;
717 
718 efault:
719 	ret = -EFAULT;
720 	goto out;
721 }
722