xref: /openbmc/linux/net/rxrpc/output.c (revision 3557b3fd)
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/export.h>
18 #include <net/sock.h>
19 #include <net/af_rxrpc.h>
20 #include "ar-internal.h"
21 
22 struct rxrpc_ack_buffer {
23 	struct rxrpc_wire_header whdr;
24 	struct rxrpc_ackpacket ack;
25 	u8 acks[255];
26 	u8 pad[3];
27 	struct rxrpc_ackinfo ackinfo;
28 };
29 
30 struct rxrpc_abort_buffer {
31 	struct rxrpc_wire_header whdr;
32 	__be32 abort_code;
33 };
34 
35 static const char rxrpc_keepalive_string[] = "";
36 
37 /*
38  * Increase Tx backoff on transmission failure and clear it on success.
39  */
40 static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret)
41 {
42 	if (ret < 0) {
43 		u16 tx_backoff = READ_ONCE(call->tx_backoff);
44 
45 		if (tx_backoff < HZ)
46 			WRITE_ONCE(call->tx_backoff, tx_backoff + 1);
47 	} else {
48 		WRITE_ONCE(call->tx_backoff, 0);
49 	}
50 }
51 
52 /*
53  * Arrange for a keepalive ping a certain time after we last transmitted.  This
54  * lets the far side know we're still interested in this call and helps keep
55  * the route through any intervening firewall open.
56  *
57  * Receiving a response to the ping will prevent the ->expect_rx_by timer from
58  * expiring.
59  */
60 static void rxrpc_set_keepalive(struct rxrpc_call *call)
61 {
62 	unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
63 
64 	keepalive_at += now;
65 	WRITE_ONCE(call->keepalive_at, keepalive_at);
66 	rxrpc_reduce_call_timer(call, keepalive_at, now,
67 				rxrpc_timer_set_for_keepalive);
68 }
69 
70 /*
71  * Fill out an ACK packet.
72  */
73 static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
74 				 struct rxrpc_call *call,
75 				 struct rxrpc_ack_buffer *pkt,
76 				 rxrpc_seq_t *_hard_ack,
77 				 rxrpc_seq_t *_top,
78 				 u8 reason)
79 {
80 	rxrpc_serial_t serial;
81 	rxrpc_seq_t hard_ack, top, seq;
82 	int ix;
83 	u32 mtu, jmax;
84 	u8 *ackp = pkt->acks;
85 
86 	/* Barrier against rxrpc_input_data(). */
87 	serial = call->ackr_serial;
88 	hard_ack = READ_ONCE(call->rx_hard_ack);
89 	top = smp_load_acquire(&call->rx_top);
90 	*_hard_ack = hard_ack;
91 	*_top = top;
92 
93 	pkt->ack.bufferSpace	= htons(8);
94 	pkt->ack.maxSkew	= htons(call->ackr_skew);
95 	pkt->ack.firstPacket	= htonl(hard_ack + 1);
96 	pkt->ack.previousPacket	= htonl(call->ackr_prev_seq);
97 	pkt->ack.serial		= htonl(serial);
98 	pkt->ack.reason		= reason;
99 	pkt->ack.nAcks		= top - hard_ack;
100 
101 	if (reason == RXRPC_ACK_PING)
102 		pkt->whdr.flags |= RXRPC_REQUEST_ACK;
103 
104 	if (after(top, hard_ack)) {
105 		seq = hard_ack + 1;
106 		do {
107 			ix = seq & RXRPC_RXTX_BUFF_MASK;
108 			if (call->rxtx_buffer[ix])
109 				*ackp++ = RXRPC_ACK_TYPE_ACK;
110 			else
111 				*ackp++ = RXRPC_ACK_TYPE_NACK;
112 			seq++;
113 		} while (before_eq(seq, top));
114 	}
115 
116 	mtu = conn->params.peer->if_mtu;
117 	mtu -= conn->params.peer->hdrsize;
118 	jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
119 	pkt->ackinfo.rxMTU	= htonl(rxrpc_rx_mtu);
120 	pkt->ackinfo.maxMTU	= htonl(mtu);
121 	pkt->ackinfo.rwind	= htonl(call->rx_winsize);
122 	pkt->ackinfo.jumbo_max	= htonl(jmax);
123 
124 	*ackp++ = 0;
125 	*ackp++ = 0;
126 	*ackp++ = 0;
127 	return top - hard_ack + 3;
128 }
129 
130 /*
131  * Send an ACK call packet.
132  */
133 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
134 			  rxrpc_serial_t *_serial)
135 {
136 	struct rxrpc_connection *conn = NULL;
137 	struct rxrpc_ack_buffer *pkt;
138 	struct msghdr msg;
139 	struct kvec iov[2];
140 	rxrpc_serial_t serial;
141 	rxrpc_seq_t hard_ack, top;
142 	size_t len, n;
143 	int ret;
144 	u8 reason;
145 
146 	spin_lock_bh(&call->lock);
147 	if (call->conn)
148 		conn = rxrpc_get_connection_maybe(call->conn);
149 	spin_unlock_bh(&call->lock);
150 	if (!conn)
151 		return -ECONNRESET;
152 
153 	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
154 	if (!pkt) {
155 		rxrpc_put_connection(conn);
156 		return -ENOMEM;
157 	}
158 
159 	msg.msg_name	= &call->peer->srx.transport;
160 	msg.msg_namelen	= call->peer->srx.transport_len;
161 	msg.msg_control	= NULL;
162 	msg.msg_controllen = 0;
163 	msg.msg_flags	= 0;
164 
165 	pkt->whdr.epoch		= htonl(conn->proto.epoch);
166 	pkt->whdr.cid		= htonl(call->cid);
167 	pkt->whdr.callNumber	= htonl(call->call_id);
168 	pkt->whdr.seq		= 0;
169 	pkt->whdr.type		= RXRPC_PACKET_TYPE_ACK;
170 	pkt->whdr.flags		= RXRPC_SLOW_START_OK | conn->out_clientflag;
171 	pkt->whdr.userStatus	= 0;
172 	pkt->whdr.securityIndex	= call->security_ix;
173 	pkt->whdr._rsvd		= 0;
174 	pkt->whdr.serviceId	= htons(call->service_id);
175 
176 	spin_lock_bh(&call->lock);
177 	if (ping) {
178 		reason = RXRPC_ACK_PING;
179 	} else {
180 		reason = call->ackr_reason;
181 		if (!call->ackr_reason) {
182 			spin_unlock_bh(&call->lock);
183 			ret = 0;
184 			goto out;
185 		}
186 		call->ackr_reason = 0;
187 	}
188 	n = rxrpc_fill_out_ack(conn, call, pkt, &hard_ack, &top, reason);
189 
190 	spin_unlock_bh(&call->lock);
191 
192 	iov[0].iov_base	= pkt;
193 	iov[0].iov_len	= sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
194 	iov[1].iov_base = &pkt->ackinfo;
195 	iov[1].iov_len	= sizeof(pkt->ackinfo);
196 	len = iov[0].iov_len + iov[1].iov_len;
197 
198 	serial = atomic_inc_return(&conn->serial);
199 	pkt->whdr.serial = htonl(serial);
200 	trace_rxrpc_tx_ack(call->debug_id, serial,
201 			   ntohl(pkt->ack.firstPacket),
202 			   ntohl(pkt->ack.serial),
203 			   pkt->ack.reason, pkt->ack.nAcks);
204 	if (_serial)
205 		*_serial = serial;
206 
207 	if (ping) {
208 		call->ping_serial = serial;
209 		smp_wmb();
210 		/* We need to stick a time in before we send the packet in case
211 		 * the reply gets back before kernel_sendmsg() completes - but
212 		 * asking UDP to send the packet can take a relatively long
213 		 * time.
214 		 */
215 		call->ping_time = ktime_get_real();
216 		set_bit(RXRPC_CALL_PINGING, &call->flags);
217 		trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
218 	}
219 
220 	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
221 	conn->params.peer->last_tx_at = ktime_get_seconds();
222 	if (ret < 0)
223 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
224 				    rxrpc_tx_point_call_ack);
225 	else
226 		trace_rxrpc_tx_packet(call->debug_id, &pkt->whdr,
227 				      rxrpc_tx_point_call_ack);
228 	rxrpc_tx_backoff(call, ret);
229 
230 	if (call->state < RXRPC_CALL_COMPLETE) {
231 		if (ret < 0) {
232 			if (ping)
233 				clear_bit(RXRPC_CALL_PINGING, &call->flags);
234 			rxrpc_propose_ACK(call, pkt->ack.reason,
235 					  ntohs(pkt->ack.maxSkew),
236 					  ntohl(pkt->ack.serial),
237 					  false, true,
238 					  rxrpc_propose_ack_retry_tx);
239 		} else {
240 			spin_lock_bh(&call->lock);
241 			if (after(hard_ack, call->ackr_consumed))
242 				call->ackr_consumed = hard_ack;
243 			if (after(top, call->ackr_seen))
244 				call->ackr_seen = top;
245 			spin_unlock_bh(&call->lock);
246 		}
247 
248 		rxrpc_set_keepalive(call);
249 	}
250 
251 out:
252 	rxrpc_put_connection(conn);
253 	kfree(pkt);
254 	return ret;
255 }
256 
257 /*
258  * Send an ABORT call packet.
259  */
260 int rxrpc_send_abort_packet(struct rxrpc_call *call)
261 {
262 	struct rxrpc_connection *conn = NULL;
263 	struct rxrpc_abort_buffer pkt;
264 	struct msghdr msg;
265 	struct kvec iov[1];
266 	rxrpc_serial_t serial;
267 	int ret;
268 
269 	/* Don't bother sending aborts for a client call once the server has
270 	 * hard-ACK'd all of its request data.  After that point, we're not
271 	 * going to stop the operation proceeding, and whilst we might limit
272 	 * the reply, it's not worth it if we can send a new call on the same
273 	 * channel instead, thereby closing off this call.
274 	 */
275 	if (rxrpc_is_client_call(call) &&
276 	    test_bit(RXRPC_CALL_TX_LAST, &call->flags))
277 		return 0;
278 
279 	spin_lock_bh(&call->lock);
280 	if (call->conn)
281 		conn = rxrpc_get_connection_maybe(call->conn);
282 	spin_unlock_bh(&call->lock);
283 	if (!conn)
284 		return -ECONNRESET;
285 
286 	msg.msg_name	= &call->peer->srx.transport;
287 	msg.msg_namelen	= call->peer->srx.transport_len;
288 	msg.msg_control	= NULL;
289 	msg.msg_controllen = 0;
290 	msg.msg_flags	= 0;
291 
292 	pkt.whdr.epoch		= htonl(conn->proto.epoch);
293 	pkt.whdr.cid		= htonl(call->cid);
294 	pkt.whdr.callNumber	= htonl(call->call_id);
295 	pkt.whdr.seq		= 0;
296 	pkt.whdr.type		= RXRPC_PACKET_TYPE_ABORT;
297 	pkt.whdr.flags		= conn->out_clientflag;
298 	pkt.whdr.userStatus	= 0;
299 	pkt.whdr.securityIndex	= call->security_ix;
300 	pkt.whdr._rsvd		= 0;
301 	pkt.whdr.serviceId	= htons(call->service_id);
302 	pkt.abort_code		= htonl(call->abort_code);
303 
304 	iov[0].iov_base	= &pkt;
305 	iov[0].iov_len	= sizeof(pkt);
306 
307 	serial = atomic_inc_return(&conn->serial);
308 	pkt.whdr.serial = htonl(serial);
309 
310 	ret = kernel_sendmsg(conn->params.local->socket,
311 			     &msg, iov, 1, sizeof(pkt));
312 	conn->params.peer->last_tx_at = ktime_get_seconds();
313 	if (ret < 0)
314 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
315 				    rxrpc_tx_point_call_abort);
316 	else
317 		trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
318 				      rxrpc_tx_point_call_abort);
319 	rxrpc_tx_backoff(call, ret);
320 
321 	rxrpc_put_connection(conn);
322 	return ret;
323 }
324 
325 /*
326  * send a packet through the transport endpoint
327  */
328 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
329 			   bool retrans)
330 {
331 	struct rxrpc_connection *conn = call->conn;
332 	struct rxrpc_wire_header whdr;
333 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
334 	struct msghdr msg;
335 	struct kvec iov[2];
336 	rxrpc_serial_t serial;
337 	size_t len;
338 	int ret, opt;
339 
340 	_enter(",{%d}", skb->len);
341 
342 	/* Each transmission of a Tx packet needs a new serial number */
343 	serial = atomic_inc_return(&conn->serial);
344 
345 	whdr.epoch	= htonl(conn->proto.epoch);
346 	whdr.cid	= htonl(call->cid);
347 	whdr.callNumber	= htonl(call->call_id);
348 	whdr.seq	= htonl(sp->hdr.seq);
349 	whdr.serial	= htonl(serial);
350 	whdr.type	= RXRPC_PACKET_TYPE_DATA;
351 	whdr.flags	= sp->hdr.flags;
352 	whdr.userStatus	= 0;
353 	whdr.securityIndex = call->security_ix;
354 	whdr._rsvd	= htons(sp->hdr._rsvd);
355 	whdr.serviceId	= htons(call->service_id);
356 
357 	if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
358 	    sp->hdr.seq == 1)
359 		whdr.userStatus	= RXRPC_USERSTATUS_SERVICE_UPGRADE;
360 
361 	iov[0].iov_base = &whdr;
362 	iov[0].iov_len = sizeof(whdr);
363 	iov[1].iov_base = skb->head;
364 	iov[1].iov_len = skb->len;
365 	len = iov[0].iov_len + iov[1].iov_len;
366 
367 	msg.msg_name = &call->peer->srx.transport;
368 	msg.msg_namelen = call->peer->srx.transport_len;
369 	msg.msg_control = NULL;
370 	msg.msg_controllen = 0;
371 	msg.msg_flags = 0;
372 
373 	/* If our RTT cache needs working on, request an ACK.  Also request
374 	 * ACKs if a DATA packet appears to have been lost.
375 	 *
376 	 * However, we mustn't request an ACK on the last reply packet of a
377 	 * service call, lest OpenAFS incorrectly send us an ACK with some
378 	 * soft-ACKs in it and then never follow up with a proper hard ACK.
379 	 */
380 	if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) ||
381 	     rxrpc_to_server(sp)
382 	     ) &&
383 	    (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||
384 	     retrans ||
385 	     call->cong_mode == RXRPC_CALL_SLOW_START ||
386 	     (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
387 	     ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
388 			  ktime_get_real())))
389 		whdr.flags |= RXRPC_REQUEST_ACK;
390 
391 	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
392 		static int lose;
393 		if ((lose++ & 7) == 7) {
394 			ret = 0;
395 			trace_rxrpc_tx_data(call, sp->hdr.seq, serial,
396 					    whdr.flags, retrans, true);
397 			goto done;
398 		}
399 	}
400 
401 	trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, retrans,
402 			    false);
403 
404 	/* send the packet with the don't fragment bit set if we currently
405 	 * think it's small enough */
406 	if (iov[1].iov_len >= call->peer->maxdata)
407 		goto send_fragmentable;
408 
409 	down_read(&conn->params.local->defrag_sem);
410 
411 	sp->hdr.serial = serial;
412 	smp_wmb(); /* Set serial before timestamp */
413 	skb->tstamp = ktime_get_real();
414 
415 	/* send the packet by UDP
416 	 * - returns -EMSGSIZE if UDP would have to fragment the packet
417 	 *   to go out of the interface
418 	 *   - in which case, we'll have processed the ICMP error
419 	 *     message and update the peer record
420 	 */
421 	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
422 	conn->params.peer->last_tx_at = ktime_get_seconds();
423 
424 	up_read(&conn->params.local->defrag_sem);
425 	if (ret < 0)
426 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
427 				    rxrpc_tx_point_call_data_nofrag);
428 	else
429 		trace_rxrpc_tx_packet(call->debug_id, &whdr,
430 				      rxrpc_tx_point_call_data_nofrag);
431 	rxrpc_tx_backoff(call, ret);
432 	if (ret == -EMSGSIZE)
433 		goto send_fragmentable;
434 
435 done:
436 	if (ret >= 0) {
437 		if (whdr.flags & RXRPC_REQUEST_ACK) {
438 			call->peer->rtt_last_req = skb->tstamp;
439 			trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
440 			if (call->peer->rtt_usage > 1) {
441 				unsigned long nowj = jiffies, ack_lost_at;
442 
443 				ack_lost_at = nsecs_to_jiffies(2 * call->peer->rtt);
444 				if (ack_lost_at < 1)
445 					ack_lost_at = 1;
446 
447 				ack_lost_at += nowj;
448 				WRITE_ONCE(call->ack_lost_at, ack_lost_at);
449 				rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
450 							rxrpc_timer_set_for_lost_ack);
451 			}
452 		}
453 
454 		if (sp->hdr.seq == 1 &&
455 		    !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
456 				      &call->flags)) {
457 			unsigned long nowj = jiffies, expect_rx_by;
458 
459 			expect_rx_by = nowj + call->next_rx_timo;
460 			WRITE_ONCE(call->expect_rx_by, expect_rx_by);
461 			rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
462 						rxrpc_timer_set_for_normal);
463 		}
464 
465 		rxrpc_set_keepalive(call);
466 	} else {
467 		/* Cancel the call if the initial transmission fails,
468 		 * particularly if that's due to network routing issues that
469 		 * aren't going away anytime soon.  The layer above can arrange
470 		 * the retransmission.
471 		 */
472 		if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags))
473 			rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
474 						  RX_USER_ABORT, ret);
475 	}
476 
477 	_leave(" = %d [%u]", ret, call->peer->maxdata);
478 	return ret;
479 
480 send_fragmentable:
481 	/* attempt to send this message with fragmentation enabled */
482 	_debug("send fragment");
483 
484 	down_write(&conn->params.local->defrag_sem);
485 
486 	sp->hdr.serial = serial;
487 	smp_wmb(); /* Set serial before timestamp */
488 	skb->tstamp = ktime_get_real();
489 
490 	switch (conn->params.local->srx.transport.family) {
491 	case AF_INET:
492 		opt = IP_PMTUDISC_DONT;
493 		ret = kernel_setsockopt(conn->params.local->socket,
494 					SOL_IP, IP_MTU_DISCOVER,
495 					(char *)&opt, sizeof(opt));
496 		if (ret == 0) {
497 			ret = kernel_sendmsg(conn->params.local->socket, &msg,
498 					     iov, 2, len);
499 			conn->params.peer->last_tx_at = ktime_get_seconds();
500 
501 			opt = IP_PMTUDISC_DO;
502 			kernel_setsockopt(conn->params.local->socket, SOL_IP,
503 					  IP_MTU_DISCOVER,
504 					  (char *)&opt, sizeof(opt));
505 		}
506 		break;
507 
508 #ifdef CONFIG_AF_RXRPC_IPV6
509 	case AF_INET6:
510 		opt = IPV6_PMTUDISC_DONT;
511 		ret = kernel_setsockopt(conn->params.local->socket,
512 					SOL_IPV6, IPV6_MTU_DISCOVER,
513 					(char *)&opt, sizeof(opt));
514 		if (ret == 0) {
515 			ret = kernel_sendmsg(conn->params.local->socket, &msg,
516 					     iov, 2, len);
517 			conn->params.peer->last_tx_at = ktime_get_seconds();
518 
519 			opt = IPV6_PMTUDISC_DO;
520 			kernel_setsockopt(conn->params.local->socket,
521 					  SOL_IPV6, IPV6_MTU_DISCOVER,
522 					  (char *)&opt, sizeof(opt));
523 		}
524 		break;
525 #endif
526 	}
527 
528 	if (ret < 0)
529 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
530 				    rxrpc_tx_point_call_data_frag);
531 	else
532 		trace_rxrpc_tx_packet(call->debug_id, &whdr,
533 				      rxrpc_tx_point_call_data_frag);
534 	rxrpc_tx_backoff(call, ret);
535 
536 	up_write(&conn->params.local->defrag_sem);
537 	goto done;
538 }
539 
540 /*
541  * reject packets through the local endpoint
542  */
543 void rxrpc_reject_packets(struct rxrpc_local *local)
544 {
545 	struct sockaddr_rxrpc srx;
546 	struct rxrpc_skb_priv *sp;
547 	struct rxrpc_wire_header whdr;
548 	struct sk_buff *skb;
549 	struct msghdr msg;
550 	struct kvec iov[2];
551 	size_t size;
552 	__be32 code;
553 	int ret, ioc;
554 
555 	_enter("%d", local->debug_id);
556 
557 	iov[0].iov_base = &whdr;
558 	iov[0].iov_len = sizeof(whdr);
559 	iov[1].iov_base = &code;
560 	iov[1].iov_len = sizeof(code);
561 
562 	msg.msg_name = &srx.transport;
563 	msg.msg_control = NULL;
564 	msg.msg_controllen = 0;
565 	msg.msg_flags = 0;
566 
567 	memset(&whdr, 0, sizeof(whdr));
568 
569 	while ((skb = skb_dequeue(&local->reject_queue))) {
570 		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
571 		sp = rxrpc_skb(skb);
572 
573 		switch (skb->mark) {
574 		case RXRPC_SKB_MARK_REJECT_BUSY:
575 			whdr.type = RXRPC_PACKET_TYPE_BUSY;
576 			size = sizeof(whdr);
577 			ioc = 1;
578 			break;
579 		case RXRPC_SKB_MARK_REJECT_ABORT:
580 			whdr.type = RXRPC_PACKET_TYPE_ABORT;
581 			code = htonl(skb->priority);
582 			size = sizeof(whdr) + sizeof(code);
583 			ioc = 2;
584 			break;
585 		default:
586 			rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
587 			continue;
588 		}
589 
590 		if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
591 			msg.msg_namelen = srx.transport_len;
592 
593 			whdr.epoch	= htonl(sp->hdr.epoch);
594 			whdr.cid	= htonl(sp->hdr.cid);
595 			whdr.callNumber	= htonl(sp->hdr.callNumber);
596 			whdr.serviceId	= htons(sp->hdr.serviceId);
597 			whdr.flags	= sp->hdr.flags;
598 			whdr.flags	^= RXRPC_CLIENT_INITIATED;
599 			whdr.flags	&= RXRPC_CLIENT_INITIATED;
600 
601 			ret = kernel_sendmsg(local->socket, &msg,
602 					     iov, ioc, size);
603 			if (ret < 0)
604 				trace_rxrpc_tx_fail(local->debug_id, 0, ret,
605 						    rxrpc_tx_point_reject);
606 			else
607 				trace_rxrpc_tx_packet(local->debug_id, &whdr,
608 						      rxrpc_tx_point_reject);
609 		}
610 
611 		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
612 	}
613 
614 	_leave("");
615 }
616 
617 /*
618  * Send a VERSION reply to a peer as a keepalive.
619  */
620 void rxrpc_send_keepalive(struct rxrpc_peer *peer)
621 {
622 	struct rxrpc_wire_header whdr;
623 	struct msghdr msg;
624 	struct kvec iov[2];
625 	size_t len;
626 	int ret;
627 
628 	_enter("");
629 
630 	msg.msg_name	= &peer->srx.transport;
631 	msg.msg_namelen	= peer->srx.transport_len;
632 	msg.msg_control	= NULL;
633 	msg.msg_controllen = 0;
634 	msg.msg_flags	= 0;
635 
636 	whdr.epoch	= htonl(peer->local->rxnet->epoch);
637 	whdr.cid	= 0;
638 	whdr.callNumber	= 0;
639 	whdr.seq	= 0;
640 	whdr.serial	= 0;
641 	whdr.type	= RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
642 	whdr.flags	= RXRPC_LAST_PACKET;
643 	whdr.userStatus	= 0;
644 	whdr.securityIndex = 0;
645 	whdr._rsvd	= 0;
646 	whdr.serviceId	= 0;
647 
648 	iov[0].iov_base	= &whdr;
649 	iov[0].iov_len	= sizeof(whdr);
650 	iov[1].iov_base	= (char *)rxrpc_keepalive_string;
651 	iov[1].iov_len	= sizeof(rxrpc_keepalive_string);
652 
653 	len = iov[0].iov_len + iov[1].iov_len;
654 
655 	_proto("Tx VERSION (keepalive)");
656 
657 	ret = kernel_sendmsg(peer->local->socket, &msg, iov, 2, len);
658 	if (ret < 0)
659 		trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
660 				    rxrpc_tx_point_version_keepalive);
661 	else
662 		trace_rxrpc_tx_packet(peer->debug_id, &whdr,
663 				      rxrpc_tx_point_version_keepalive);
664 
665 	peer->last_tx_at = ktime_get_seconds();
666 	_leave("");
667 }
668