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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  */
rxrpc_tx_backoff(struct rxrpc_call * call,int ret)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  */
rxrpc_set_keepalive(struct rxrpc_call * call)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  */
rxrpc_fill_out_ack(struct rxrpc_connection * conn,struct rxrpc_call * call,struct rxrpc_ack_buffer * pkt,rxrpc_seq_t * _hard_ack,rxrpc_seq_t * _top,u8 reason)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  */
rxrpc_send_ack_packet(struct rxrpc_call * call,bool ping,rxrpc_serial_t * _serial)133 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
134 			  rxrpc_serial_t *_serial)
135 {
136 	struct rxrpc_connection *conn;
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 	if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
147 		return -ECONNRESET;
148 
149 	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
150 	if (!pkt)
151 		return -ENOMEM;
152 
153 	conn = call->conn;
154 
155 	msg.msg_name	= &call->peer->srx.transport;
156 	msg.msg_namelen	= call->peer->srx.transport_len;
157 	msg.msg_control	= NULL;
158 	msg.msg_controllen = 0;
159 	msg.msg_flags	= 0;
160 
161 	pkt->whdr.epoch		= htonl(conn->proto.epoch);
162 	pkt->whdr.cid		= htonl(call->cid);
163 	pkt->whdr.callNumber	= htonl(call->call_id);
164 	pkt->whdr.seq		= 0;
165 	pkt->whdr.type		= RXRPC_PACKET_TYPE_ACK;
166 	pkt->whdr.flags		= RXRPC_SLOW_START_OK | conn->out_clientflag;
167 	pkt->whdr.userStatus	= 0;
168 	pkt->whdr.securityIndex	= call->security_ix;
169 	pkt->whdr._rsvd		= 0;
170 	pkt->whdr.serviceId	= htons(call->service_id);
171 
172 	spin_lock_bh(&call->lock);
173 	if (ping) {
174 		reason = RXRPC_ACK_PING;
175 	} else {
176 		reason = call->ackr_reason;
177 		if (!call->ackr_reason) {
178 			spin_unlock_bh(&call->lock);
179 			ret = 0;
180 			goto out;
181 		}
182 		call->ackr_reason = 0;
183 	}
184 	n = rxrpc_fill_out_ack(conn, call, pkt, &hard_ack, &top, reason);
185 
186 	spin_unlock_bh(&call->lock);
187 
188 	iov[0].iov_base	= pkt;
189 	iov[0].iov_len	= sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
190 	iov[1].iov_base = &pkt->ackinfo;
191 	iov[1].iov_len	= sizeof(pkt->ackinfo);
192 	len = iov[0].iov_len + iov[1].iov_len;
193 
194 	serial = atomic_inc_return(&conn->serial);
195 	pkt->whdr.serial = htonl(serial);
196 	trace_rxrpc_tx_ack(call->debug_id, serial,
197 			   ntohl(pkt->ack.firstPacket),
198 			   ntohl(pkt->ack.serial),
199 			   pkt->ack.reason, pkt->ack.nAcks);
200 	if (_serial)
201 		*_serial = serial;
202 
203 	if (ping) {
204 		call->ping_serial = serial;
205 		smp_wmb();
206 		/* We need to stick a time in before we send the packet in case
207 		 * the reply gets back before kernel_sendmsg() completes - but
208 		 * asking UDP to send the packet can take a relatively long
209 		 * time.
210 		 */
211 		call->ping_time = ktime_get_real();
212 		set_bit(RXRPC_CALL_PINGING, &call->flags);
213 		trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
214 	}
215 
216 	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
217 	conn->params.peer->last_tx_at = ktime_get_seconds();
218 	if (ret < 0)
219 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
220 				    rxrpc_tx_point_call_ack);
221 	else
222 		trace_rxrpc_tx_packet(call->debug_id, &pkt->whdr,
223 				      rxrpc_tx_point_call_ack);
224 	rxrpc_tx_backoff(call, ret);
225 
226 	if (call->state < RXRPC_CALL_COMPLETE) {
227 		if (ret < 0) {
228 			if (ping)
229 				clear_bit(RXRPC_CALL_PINGING, &call->flags);
230 			rxrpc_propose_ACK(call, pkt->ack.reason,
231 					  ntohs(pkt->ack.maxSkew),
232 					  ntohl(pkt->ack.serial),
233 					  false, true,
234 					  rxrpc_propose_ack_retry_tx);
235 		} else {
236 			spin_lock_bh(&call->lock);
237 			if (after(hard_ack, call->ackr_consumed))
238 				call->ackr_consumed = hard_ack;
239 			if (after(top, call->ackr_seen))
240 				call->ackr_seen = top;
241 			spin_unlock_bh(&call->lock);
242 		}
243 
244 		rxrpc_set_keepalive(call);
245 	}
246 
247 out:
248 	kfree(pkt);
249 	return ret;
250 }
251 
252 /*
253  * Send an ABORT call packet.
254  */
rxrpc_send_abort_packet(struct rxrpc_call * call)255 int rxrpc_send_abort_packet(struct rxrpc_call *call)
256 {
257 	struct rxrpc_connection *conn;
258 	struct rxrpc_abort_buffer pkt;
259 	struct msghdr msg;
260 	struct kvec iov[1];
261 	rxrpc_serial_t serial;
262 	int ret;
263 
264 	/* Don't bother sending aborts for a client call once the server has
265 	 * hard-ACK'd all of its request data.  After that point, we're not
266 	 * going to stop the operation proceeding, and whilst we might limit
267 	 * the reply, it's not worth it if we can send a new call on the same
268 	 * channel instead, thereby closing off this call.
269 	 */
270 	if (rxrpc_is_client_call(call) &&
271 	    test_bit(RXRPC_CALL_TX_LAST, &call->flags))
272 		return 0;
273 
274 	if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
275 		return -ECONNRESET;
276 
277 	conn = call->conn;
278 
279 	msg.msg_name	= &call->peer->srx.transport;
280 	msg.msg_namelen	= call->peer->srx.transport_len;
281 	msg.msg_control	= NULL;
282 	msg.msg_controllen = 0;
283 	msg.msg_flags	= 0;
284 
285 	pkt.whdr.epoch		= htonl(conn->proto.epoch);
286 	pkt.whdr.cid		= htonl(call->cid);
287 	pkt.whdr.callNumber	= htonl(call->call_id);
288 	pkt.whdr.seq		= 0;
289 	pkt.whdr.type		= RXRPC_PACKET_TYPE_ABORT;
290 	pkt.whdr.flags		= conn->out_clientflag;
291 	pkt.whdr.userStatus	= 0;
292 	pkt.whdr.securityIndex	= call->security_ix;
293 	pkt.whdr._rsvd		= 0;
294 	pkt.whdr.serviceId	= htons(call->service_id);
295 	pkt.abort_code		= htonl(call->abort_code);
296 
297 	iov[0].iov_base	= &pkt;
298 	iov[0].iov_len	= sizeof(pkt);
299 
300 	serial = atomic_inc_return(&conn->serial);
301 	pkt.whdr.serial = htonl(serial);
302 
303 	ret = kernel_sendmsg(conn->params.local->socket,
304 			     &msg, iov, 1, sizeof(pkt));
305 	conn->params.peer->last_tx_at = ktime_get_seconds();
306 	if (ret < 0)
307 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
308 				    rxrpc_tx_point_call_abort);
309 	else
310 		trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
311 				      rxrpc_tx_point_call_abort);
312 	rxrpc_tx_backoff(call, ret);
313 	return ret;
314 }
315 
316 /*
317  * send a packet through the transport endpoint
318  */
rxrpc_send_data_packet(struct rxrpc_call * call,struct sk_buff * skb,bool retrans)319 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
320 			   bool retrans)
321 {
322 	struct rxrpc_connection *conn = call->conn;
323 	struct rxrpc_wire_header whdr;
324 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
325 	struct msghdr msg;
326 	struct kvec iov[2];
327 	rxrpc_serial_t serial;
328 	size_t len;
329 	bool lost = false;
330 	int ret, opt;
331 
332 	_enter(",{%d}", skb->len);
333 
334 	/* Each transmission of a Tx packet needs a new serial number */
335 	serial = atomic_inc_return(&conn->serial);
336 
337 	whdr.epoch	= htonl(conn->proto.epoch);
338 	whdr.cid	= htonl(call->cid);
339 	whdr.callNumber	= htonl(call->call_id);
340 	whdr.seq	= htonl(sp->hdr.seq);
341 	whdr.serial	= htonl(serial);
342 	whdr.type	= RXRPC_PACKET_TYPE_DATA;
343 	whdr.flags	= sp->hdr.flags;
344 	whdr.userStatus	= 0;
345 	whdr.securityIndex = call->security_ix;
346 	whdr._rsvd	= htons(sp->hdr._rsvd);
347 	whdr.serviceId	= htons(call->service_id);
348 
349 	if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
350 	    sp->hdr.seq == 1)
351 		whdr.userStatus	= RXRPC_USERSTATUS_SERVICE_UPGRADE;
352 
353 	iov[0].iov_base = &whdr;
354 	iov[0].iov_len = sizeof(whdr);
355 	iov[1].iov_base = skb->head;
356 	iov[1].iov_len = skb->len;
357 	len = iov[0].iov_len + iov[1].iov_len;
358 
359 	msg.msg_name = &call->peer->srx.transport;
360 	msg.msg_namelen = call->peer->srx.transport_len;
361 	msg.msg_control = NULL;
362 	msg.msg_controllen = 0;
363 	msg.msg_flags = 0;
364 
365 	/* If our RTT cache needs working on, request an ACK.  Also request
366 	 * ACKs if a DATA packet appears to have been lost.
367 	 *
368 	 * However, we mustn't request an ACK on the last reply packet of a
369 	 * service call, lest OpenAFS incorrectly send us an ACK with some
370 	 * soft-ACKs in it and then never follow up with a proper hard ACK.
371 	 */
372 	if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) ||
373 	     rxrpc_to_server(sp)
374 	     ) &&
375 	    (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||
376 	     retrans ||
377 	     call->cong_mode == RXRPC_CALL_SLOW_START ||
378 	     (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
379 	     ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
380 			  ktime_get_real())))
381 		whdr.flags |= RXRPC_REQUEST_ACK;
382 
383 	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
384 		static int lose;
385 		if ((lose++ & 7) == 7) {
386 			ret = 0;
387 			lost = true;
388 			goto done;
389 		}
390 	}
391 
392 	_proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
393 
394 	/* send the packet with the don't fragment bit set if we currently
395 	 * think it's small enough */
396 	if (iov[1].iov_len >= call->peer->maxdata)
397 		goto send_fragmentable;
398 
399 	down_read(&conn->params.local->defrag_sem);
400 
401 	sp->hdr.serial = serial;
402 	smp_wmb(); /* Set serial before timestamp */
403 	skb->tstamp = ktime_get_real();
404 
405 	/* send the packet by UDP
406 	 * - returns -EMSGSIZE if UDP would have to fragment the packet
407 	 *   to go out of the interface
408 	 *   - in which case, we'll have processed the ICMP error
409 	 *     message and update the peer record
410 	 */
411 	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
412 	conn->params.peer->last_tx_at = ktime_get_seconds();
413 
414 	up_read(&conn->params.local->defrag_sem);
415 	if (ret < 0)
416 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
417 				    rxrpc_tx_point_call_data_nofrag);
418 	else
419 		trace_rxrpc_tx_packet(call->debug_id, &whdr,
420 				      rxrpc_tx_point_call_data_nofrag);
421 	rxrpc_tx_backoff(call, ret);
422 	if (ret == -EMSGSIZE)
423 		goto send_fragmentable;
424 
425 done:
426 	trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
427 			    retrans, lost);
428 	if (ret >= 0) {
429 		if (whdr.flags & RXRPC_REQUEST_ACK) {
430 			call->peer->rtt_last_req = skb->tstamp;
431 			trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
432 			if (call->peer->rtt_usage > 1) {
433 				unsigned long nowj = jiffies, ack_lost_at;
434 
435 				ack_lost_at = nsecs_to_jiffies(2 * call->peer->rtt);
436 				if (ack_lost_at < 1)
437 					ack_lost_at = 1;
438 
439 				ack_lost_at += nowj;
440 				WRITE_ONCE(call->ack_lost_at, ack_lost_at);
441 				rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
442 							rxrpc_timer_set_for_lost_ack);
443 			}
444 		}
445 
446 		if (sp->hdr.seq == 1 &&
447 		    !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
448 				      &call->flags)) {
449 			unsigned long nowj = jiffies, expect_rx_by;
450 
451 			expect_rx_by = nowj + call->next_rx_timo;
452 			WRITE_ONCE(call->expect_rx_by, expect_rx_by);
453 			rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
454 						rxrpc_timer_set_for_normal);
455 		}
456 
457 		rxrpc_set_keepalive(call);
458 	} else {
459 		/* Cancel the call if the initial transmission fails,
460 		 * particularly if that's due to network routing issues that
461 		 * aren't going away anytime soon.  The layer above can arrange
462 		 * the retransmission.
463 		 */
464 		if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags))
465 			rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
466 						  RX_USER_ABORT, ret);
467 	}
468 
469 	_leave(" = %d [%u]", ret, call->peer->maxdata);
470 	return ret;
471 
472 send_fragmentable:
473 	/* attempt to send this message with fragmentation enabled */
474 	_debug("send fragment");
475 
476 	down_write(&conn->params.local->defrag_sem);
477 
478 	sp->hdr.serial = serial;
479 	smp_wmb(); /* Set serial before timestamp */
480 	skb->tstamp = ktime_get_real();
481 
482 	switch (conn->params.local->srx.transport.family) {
483 	case AF_INET6:
484 	case AF_INET:
485 		opt = IP_PMTUDISC_DONT;
486 		kernel_setsockopt(conn->params.local->socket,
487 				  SOL_IP, IP_MTU_DISCOVER,
488 				  (char *)&opt, sizeof(opt));
489 		ret = kernel_sendmsg(conn->params.local->socket, &msg,
490 				     iov, 2, len);
491 		conn->params.peer->last_tx_at = ktime_get_seconds();
492 
493 		opt = IP_PMTUDISC_DO;
494 		kernel_setsockopt(conn->params.local->socket,
495 				  SOL_IP, IP_MTU_DISCOVER,
496 				  (char *)&opt, sizeof(opt));
497 		break;
498 
499 	default:
500 		BUG();
501 	}
502 
503 	if (ret < 0)
504 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
505 				    rxrpc_tx_point_call_data_frag);
506 	else
507 		trace_rxrpc_tx_packet(call->debug_id, &whdr,
508 				      rxrpc_tx_point_call_data_frag);
509 	rxrpc_tx_backoff(call, ret);
510 
511 	up_write(&conn->params.local->defrag_sem);
512 	goto done;
513 }
514 
515 /*
516  * reject packets through the local endpoint
517  */
rxrpc_reject_packets(struct rxrpc_local * local)518 void rxrpc_reject_packets(struct rxrpc_local *local)
519 {
520 	struct sockaddr_rxrpc srx;
521 	struct rxrpc_skb_priv *sp;
522 	struct rxrpc_wire_header whdr;
523 	struct sk_buff *skb;
524 	struct msghdr msg;
525 	struct kvec iov[2];
526 	size_t size;
527 	__be32 code;
528 	int ret, ioc;
529 
530 	_enter("%d", local->debug_id);
531 
532 	iov[0].iov_base = &whdr;
533 	iov[0].iov_len = sizeof(whdr);
534 	iov[1].iov_base = &code;
535 	iov[1].iov_len = sizeof(code);
536 
537 	msg.msg_name = &srx.transport;
538 	msg.msg_control = NULL;
539 	msg.msg_controllen = 0;
540 	msg.msg_flags = 0;
541 
542 	memset(&whdr, 0, sizeof(whdr));
543 
544 	while ((skb = skb_dequeue(&local->reject_queue))) {
545 		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
546 		sp = rxrpc_skb(skb);
547 
548 		switch (skb->mark) {
549 		case RXRPC_SKB_MARK_REJECT_BUSY:
550 			whdr.type = RXRPC_PACKET_TYPE_BUSY;
551 			size = sizeof(whdr);
552 			ioc = 1;
553 			break;
554 		case RXRPC_SKB_MARK_REJECT_ABORT:
555 			whdr.type = RXRPC_PACKET_TYPE_ABORT;
556 			code = htonl(skb->priority);
557 			size = sizeof(whdr) + sizeof(code);
558 			ioc = 2;
559 			break;
560 		default:
561 			rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
562 			continue;
563 		}
564 
565 		if (rxrpc_extract_addr_from_skb(local, &srx, skb) == 0) {
566 			msg.msg_namelen = srx.transport_len;
567 
568 			whdr.epoch	= htonl(sp->hdr.epoch);
569 			whdr.cid	= htonl(sp->hdr.cid);
570 			whdr.callNumber	= htonl(sp->hdr.callNumber);
571 			whdr.serviceId	= htons(sp->hdr.serviceId);
572 			whdr.flags	= sp->hdr.flags;
573 			whdr.flags	^= RXRPC_CLIENT_INITIATED;
574 			whdr.flags	&= RXRPC_CLIENT_INITIATED;
575 
576 			ret = kernel_sendmsg(local->socket, &msg,
577 					     iov, ioc, size);
578 			if (ret < 0)
579 				trace_rxrpc_tx_fail(local->debug_id, 0, ret,
580 						    rxrpc_tx_point_reject);
581 			else
582 				trace_rxrpc_tx_packet(local->debug_id, &whdr,
583 						      rxrpc_tx_point_reject);
584 		}
585 
586 		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
587 	}
588 
589 	_leave("");
590 }
591 
592 /*
593  * Send a VERSION reply to a peer as a keepalive.
594  */
rxrpc_send_keepalive(struct rxrpc_peer * peer)595 void rxrpc_send_keepalive(struct rxrpc_peer *peer)
596 {
597 	struct rxrpc_wire_header whdr;
598 	struct msghdr msg;
599 	struct kvec iov[2];
600 	size_t len;
601 	int ret;
602 
603 	_enter("");
604 
605 	msg.msg_name	= &peer->srx.transport;
606 	msg.msg_namelen	= peer->srx.transport_len;
607 	msg.msg_control	= NULL;
608 	msg.msg_controllen = 0;
609 	msg.msg_flags	= 0;
610 
611 	whdr.epoch	= htonl(peer->local->rxnet->epoch);
612 	whdr.cid	= 0;
613 	whdr.callNumber	= 0;
614 	whdr.seq	= 0;
615 	whdr.serial	= 0;
616 	whdr.type	= RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
617 	whdr.flags	= RXRPC_LAST_PACKET;
618 	whdr.userStatus	= 0;
619 	whdr.securityIndex = 0;
620 	whdr._rsvd	= 0;
621 	whdr.serviceId	= 0;
622 
623 	iov[0].iov_base	= &whdr;
624 	iov[0].iov_len	= sizeof(whdr);
625 	iov[1].iov_base	= (char *)rxrpc_keepalive_string;
626 	iov[1].iov_len	= sizeof(rxrpc_keepalive_string);
627 
628 	len = iov[0].iov_len + iov[1].iov_len;
629 
630 	_proto("Tx VERSION (keepalive)");
631 
632 	ret = kernel_sendmsg(peer->local->socket, &msg, iov, 2, len);
633 	if (ret < 0)
634 		trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
635 				    rxrpc_tx_point_version_keepalive);
636 	else
637 		trace_rxrpc_tx_packet(peer->debug_id, &whdr,
638 				      rxrpc_tx_point_version_keepalive);
639 
640 	peer->last_tx_at = ktime_get_seconds();
641 	_leave("");
642 }
643