xref: /linux/net/rxrpc/output.c (revision bf80eef2212a1e8451df13b52533f4bc31bb4f8e)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* RxRPC packet transmission
3  *
4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5  * Written by David Howells (dhowells@redhat.com)
6  */
7 
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 
10 #include <linux/net.h>
11 #include <linux/gfp.h>
12 #include <linux/skbuff.h>
13 #include <linux/export.h>
14 #include <net/sock.h>
15 #include <net/af_rxrpc.h>
16 #include "ar-internal.h"
17 
18 struct rxrpc_ack_buffer {
19 	struct rxrpc_wire_header whdr;
20 	struct rxrpc_ackpacket ack;
21 	u8 acks[255];
22 	u8 pad[3];
23 	struct rxrpc_ackinfo ackinfo;
24 };
25 
26 struct rxrpc_abort_buffer {
27 	struct rxrpc_wire_header whdr;
28 	__be32 abort_code;
29 };
30 
31 static const char rxrpc_keepalive_string[] = "";
32 
33 /*
34  * Increase Tx backoff on transmission failure and clear it on success.
35  */
36 static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret)
37 {
38 	if (ret < 0) {
39 		u16 tx_backoff = READ_ONCE(call->tx_backoff);
40 
41 		if (tx_backoff < HZ)
42 			WRITE_ONCE(call->tx_backoff, tx_backoff + 1);
43 	} else {
44 		WRITE_ONCE(call->tx_backoff, 0);
45 	}
46 }
47 
48 /*
49  * Arrange for a keepalive ping a certain time after we last transmitted.  This
50  * lets the far side know we're still interested in this call and helps keep
51  * the route through any intervening firewall open.
52  *
53  * Receiving a response to the ping will prevent the ->expect_rx_by timer from
54  * expiring.
55  */
56 static void rxrpc_set_keepalive(struct rxrpc_call *call)
57 {
58 	unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
59 
60 	keepalive_at += now;
61 	WRITE_ONCE(call->keepalive_at, keepalive_at);
62 	rxrpc_reduce_call_timer(call, keepalive_at, now,
63 				rxrpc_timer_set_for_keepalive);
64 }
65 
66 /*
67  * Fill out an ACK packet.
68  */
69 static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
70 				 struct rxrpc_call *call,
71 				 struct rxrpc_ack_buffer *pkt,
72 				 rxrpc_seq_t *_hard_ack,
73 				 rxrpc_seq_t *_top,
74 				 u8 reason)
75 {
76 	rxrpc_serial_t serial;
77 	unsigned int tmp;
78 	rxrpc_seq_t hard_ack, top, seq;
79 	int ix;
80 	u32 mtu, jmax;
81 	u8 *ackp = pkt->acks;
82 
83 	tmp = atomic_xchg(&call->ackr_nr_unacked, 0);
84 	tmp |= atomic_xchg(&call->ackr_nr_consumed, 0);
85 	if (!tmp && (reason == RXRPC_ACK_DELAY ||
86 		     reason == RXRPC_ACK_IDLE))
87 		return 0;
88 
89 	/* Barrier against rxrpc_input_data(). */
90 	serial = call->ackr_serial;
91 	hard_ack = READ_ONCE(call->rx_hard_ack);
92 	top = smp_load_acquire(&call->rx_top);
93 	*_hard_ack = hard_ack;
94 	*_top = top;
95 
96 	pkt->ack.bufferSpace	= htons(8);
97 	pkt->ack.maxSkew	= htons(0);
98 	pkt->ack.firstPacket	= htonl(hard_ack + 1);
99 	pkt->ack.previousPacket	= htonl(call->ackr_highest_seq);
100 	pkt->ack.serial		= htonl(serial);
101 	pkt->ack.reason		= reason;
102 	pkt->ack.nAcks		= top - hard_ack;
103 
104 	if (reason == RXRPC_ACK_PING)
105 		pkt->whdr.flags |= RXRPC_REQUEST_ACK;
106 
107 	if (after(top, hard_ack)) {
108 		seq = hard_ack + 1;
109 		do {
110 			ix = seq & RXRPC_RXTX_BUFF_MASK;
111 			if (call->rxtx_buffer[ix])
112 				*ackp++ = RXRPC_ACK_TYPE_ACK;
113 			else
114 				*ackp++ = RXRPC_ACK_TYPE_NACK;
115 			seq++;
116 		} while (before_eq(seq, top));
117 	}
118 
119 	mtu = conn->params.peer->if_mtu;
120 	mtu -= conn->params.peer->hdrsize;
121 	jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
122 	pkt->ackinfo.rxMTU	= htonl(rxrpc_rx_mtu);
123 	pkt->ackinfo.maxMTU	= htonl(mtu);
124 	pkt->ackinfo.rwind	= htonl(call->rx_winsize);
125 	pkt->ackinfo.jumbo_max	= htonl(jmax);
126 
127 	*ackp++ = 0;
128 	*ackp++ = 0;
129 	*ackp++ = 0;
130 	return top - hard_ack + 3;
131 }
132 
133 /*
134  * Record the beginning of an RTT probe.
135  */
136 static int rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial,
137 				 enum rxrpc_rtt_tx_trace why)
138 {
139 	unsigned long avail = call->rtt_avail;
140 	int rtt_slot = 9;
141 
142 	if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK))
143 		goto no_slot;
144 
145 	rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK);
146 	if (!test_and_clear_bit(rtt_slot, &call->rtt_avail))
147 		goto no_slot;
148 
149 	call->rtt_serial[rtt_slot] = serial;
150 	call->rtt_sent_at[rtt_slot] = ktime_get_real();
151 	smp_wmb(); /* Write data before avail bit */
152 	set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
153 
154 	trace_rxrpc_rtt_tx(call, why, rtt_slot, serial);
155 	return rtt_slot;
156 
157 no_slot:
158 	trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial);
159 	return -1;
160 }
161 
162 /*
163  * Cancel an RTT probe.
164  */
165 static void rxrpc_cancel_rtt_probe(struct rxrpc_call *call,
166 				   rxrpc_serial_t serial, int rtt_slot)
167 {
168 	if (rtt_slot != -1) {
169 		clear_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
170 		smp_wmb(); /* Clear pending bit before setting slot */
171 		set_bit(rtt_slot, &call->rtt_avail);
172 		trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_cancel, rtt_slot, serial);
173 	}
174 }
175 
176 /*
177  * Send an ACK call packet.
178  */
179 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
180 			  rxrpc_serial_t *_serial)
181 {
182 	struct rxrpc_connection *conn;
183 	struct rxrpc_ack_buffer *pkt;
184 	struct msghdr msg;
185 	struct kvec iov[2];
186 	rxrpc_serial_t serial;
187 	rxrpc_seq_t hard_ack, top;
188 	size_t len, n;
189 	int ret, rtt_slot = -1;
190 	u8 reason;
191 
192 	if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
193 		return -ECONNRESET;
194 
195 	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
196 	if (!pkt)
197 		return -ENOMEM;
198 
199 	conn = call->conn;
200 
201 	msg.msg_name	= &call->peer->srx.transport;
202 	msg.msg_namelen	= call->peer->srx.transport_len;
203 	msg.msg_control	= NULL;
204 	msg.msg_controllen = 0;
205 	msg.msg_flags	= 0;
206 
207 	pkt->whdr.epoch		= htonl(conn->proto.epoch);
208 	pkt->whdr.cid		= htonl(call->cid);
209 	pkt->whdr.callNumber	= htonl(call->call_id);
210 	pkt->whdr.seq		= 0;
211 	pkt->whdr.type		= RXRPC_PACKET_TYPE_ACK;
212 	pkt->whdr.flags		= RXRPC_SLOW_START_OK | conn->out_clientflag;
213 	pkt->whdr.userStatus	= 0;
214 	pkt->whdr.securityIndex	= call->security_ix;
215 	pkt->whdr._rsvd		= 0;
216 	pkt->whdr.serviceId	= htons(call->service_id);
217 
218 	spin_lock_bh(&call->lock);
219 	if (ping) {
220 		reason = RXRPC_ACK_PING;
221 	} else {
222 		reason = call->ackr_reason;
223 		if (!call->ackr_reason) {
224 			spin_unlock_bh(&call->lock);
225 			ret = 0;
226 			goto out;
227 		}
228 		call->ackr_reason = 0;
229 	}
230 	n = rxrpc_fill_out_ack(conn, call, pkt, &hard_ack, &top, reason);
231 
232 	spin_unlock_bh(&call->lock);
233 	if (n == 0) {
234 		kfree(pkt);
235 		return 0;
236 	}
237 
238 	iov[0].iov_base	= pkt;
239 	iov[0].iov_len	= sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
240 	iov[1].iov_base = &pkt->ackinfo;
241 	iov[1].iov_len	= sizeof(pkt->ackinfo);
242 	len = iov[0].iov_len + iov[1].iov_len;
243 
244 	serial = atomic_inc_return(&conn->serial);
245 	pkt->whdr.serial = htonl(serial);
246 	trace_rxrpc_tx_ack(call->debug_id, serial,
247 			   ntohl(pkt->ack.firstPacket),
248 			   ntohl(pkt->ack.serial),
249 			   pkt->ack.reason, pkt->ack.nAcks);
250 	if (_serial)
251 		*_serial = serial;
252 
253 	if (ping)
254 		rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_ping);
255 
256 	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
257 	conn->params.peer->last_tx_at = ktime_get_seconds();
258 	if (ret < 0)
259 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
260 				    rxrpc_tx_point_call_ack);
261 	else
262 		trace_rxrpc_tx_packet(call->debug_id, &pkt->whdr,
263 				      rxrpc_tx_point_call_ack);
264 	rxrpc_tx_backoff(call, ret);
265 
266 	if (call->state < RXRPC_CALL_COMPLETE) {
267 		if (ret < 0) {
268 			rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
269 			rxrpc_propose_ACK(call, pkt->ack.reason,
270 					  ntohl(pkt->ack.serial),
271 					  false, true,
272 					  rxrpc_propose_ack_retry_tx);
273 		}
274 
275 		rxrpc_set_keepalive(call);
276 	}
277 
278 out:
279 	kfree(pkt);
280 	return ret;
281 }
282 
283 /*
284  * Send an ABORT call packet.
285  */
286 int rxrpc_send_abort_packet(struct rxrpc_call *call)
287 {
288 	struct rxrpc_connection *conn;
289 	struct rxrpc_abort_buffer pkt;
290 	struct msghdr msg;
291 	struct kvec iov[1];
292 	rxrpc_serial_t serial;
293 	int ret;
294 
295 	/* Don't bother sending aborts for a client call once the server has
296 	 * hard-ACK'd all of its request data.  After that point, we're not
297 	 * going to stop the operation proceeding, and whilst we might limit
298 	 * the reply, it's not worth it if we can send a new call on the same
299 	 * channel instead, thereby closing off this call.
300 	 */
301 	if (rxrpc_is_client_call(call) &&
302 	    test_bit(RXRPC_CALL_TX_LAST, &call->flags))
303 		return 0;
304 
305 	if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
306 		return -ECONNRESET;
307 
308 	conn = call->conn;
309 
310 	msg.msg_name	= &call->peer->srx.transport;
311 	msg.msg_namelen	= call->peer->srx.transport_len;
312 	msg.msg_control	= NULL;
313 	msg.msg_controllen = 0;
314 	msg.msg_flags	= 0;
315 
316 	pkt.whdr.epoch		= htonl(conn->proto.epoch);
317 	pkt.whdr.cid		= htonl(call->cid);
318 	pkt.whdr.callNumber	= htonl(call->call_id);
319 	pkt.whdr.seq		= 0;
320 	pkt.whdr.type		= RXRPC_PACKET_TYPE_ABORT;
321 	pkt.whdr.flags		= conn->out_clientflag;
322 	pkt.whdr.userStatus	= 0;
323 	pkt.whdr.securityIndex	= call->security_ix;
324 	pkt.whdr._rsvd		= 0;
325 	pkt.whdr.serviceId	= htons(call->service_id);
326 	pkt.abort_code		= htonl(call->abort_code);
327 
328 	iov[0].iov_base	= &pkt;
329 	iov[0].iov_len	= sizeof(pkt);
330 
331 	serial = atomic_inc_return(&conn->serial);
332 	pkt.whdr.serial = htonl(serial);
333 
334 	ret = kernel_sendmsg(conn->params.local->socket,
335 			     &msg, iov, 1, sizeof(pkt));
336 	conn->params.peer->last_tx_at = ktime_get_seconds();
337 	if (ret < 0)
338 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
339 				    rxrpc_tx_point_call_abort);
340 	else
341 		trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
342 				      rxrpc_tx_point_call_abort);
343 	rxrpc_tx_backoff(call, ret);
344 	return ret;
345 }
346 
347 /*
348  * send a packet through the transport endpoint
349  */
350 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
351 			   bool retrans)
352 {
353 	struct rxrpc_connection *conn = call->conn;
354 	struct rxrpc_wire_header whdr;
355 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
356 	struct msghdr msg;
357 	struct kvec iov[2];
358 	rxrpc_serial_t serial;
359 	size_t len;
360 	int ret, rtt_slot = -1;
361 
362 	_enter(",{%d}", skb->len);
363 
364 	if (hlist_unhashed(&call->error_link)) {
365 		spin_lock_bh(&call->peer->lock);
366 		hlist_add_head_rcu(&call->error_link, &call->peer->error_targets);
367 		spin_unlock_bh(&call->peer->lock);
368 	}
369 
370 	/* Each transmission of a Tx packet needs a new serial number */
371 	serial = atomic_inc_return(&conn->serial);
372 
373 	whdr.epoch	= htonl(conn->proto.epoch);
374 	whdr.cid	= htonl(call->cid);
375 	whdr.callNumber	= htonl(call->call_id);
376 	whdr.seq	= htonl(sp->hdr.seq);
377 	whdr.serial	= htonl(serial);
378 	whdr.type	= RXRPC_PACKET_TYPE_DATA;
379 	whdr.flags	= sp->hdr.flags;
380 	whdr.userStatus	= 0;
381 	whdr.securityIndex = call->security_ix;
382 	whdr._rsvd	= htons(sp->hdr._rsvd);
383 	whdr.serviceId	= htons(call->service_id);
384 
385 	if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
386 	    sp->hdr.seq == 1)
387 		whdr.userStatus	= RXRPC_USERSTATUS_SERVICE_UPGRADE;
388 
389 	iov[0].iov_base = &whdr;
390 	iov[0].iov_len = sizeof(whdr);
391 	iov[1].iov_base = skb->head;
392 	iov[1].iov_len = skb->len;
393 	len = iov[0].iov_len + iov[1].iov_len;
394 
395 	msg.msg_name = &call->peer->srx.transport;
396 	msg.msg_namelen = call->peer->srx.transport_len;
397 	msg.msg_control = NULL;
398 	msg.msg_controllen = 0;
399 	msg.msg_flags = 0;
400 
401 	/* If our RTT cache needs working on, request an ACK.  Also request
402 	 * ACKs if a DATA packet appears to have been lost.
403 	 *
404 	 * However, we mustn't request an ACK on the last reply packet of a
405 	 * service call, lest OpenAFS incorrectly send us an ACK with some
406 	 * soft-ACKs in it and then never follow up with a proper hard ACK.
407 	 */
408 	if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) ||
409 	     rxrpc_to_server(sp)
410 	     ) &&
411 	    (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||
412 	     retrans ||
413 	     call->cong_mode == RXRPC_CALL_SLOW_START ||
414 	     (call->peer->rtt_count < 3 && sp->hdr.seq & 1) ||
415 	     ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
416 			  ktime_get_real())))
417 		whdr.flags |= RXRPC_REQUEST_ACK;
418 
419 	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
420 		static int lose;
421 		if ((lose++ & 7) == 7) {
422 			ret = 0;
423 			trace_rxrpc_tx_data(call, sp->hdr.seq, serial,
424 					    whdr.flags, retrans, true);
425 			goto done;
426 		}
427 	}
428 
429 	trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, retrans,
430 			    false);
431 
432 	/* send the packet with the don't fragment bit set if we currently
433 	 * think it's small enough */
434 	if (iov[1].iov_len >= call->peer->maxdata)
435 		goto send_fragmentable;
436 
437 	down_read(&conn->params.local->defrag_sem);
438 
439 	sp->hdr.serial = serial;
440 	smp_wmb(); /* Set serial before timestamp */
441 	skb->tstamp = ktime_get_real();
442 	if (whdr.flags & RXRPC_REQUEST_ACK)
443 		rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
444 
445 	/* send the packet by UDP
446 	 * - returns -EMSGSIZE if UDP would have to fragment the packet
447 	 *   to go out of the interface
448 	 *   - in which case, we'll have processed the ICMP error
449 	 *     message and update the peer record
450 	 */
451 	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
452 	conn->params.peer->last_tx_at = ktime_get_seconds();
453 
454 	up_read(&conn->params.local->defrag_sem);
455 	if (ret < 0) {
456 		rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
457 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
458 				    rxrpc_tx_point_call_data_nofrag);
459 	} else {
460 		trace_rxrpc_tx_packet(call->debug_id, &whdr,
461 				      rxrpc_tx_point_call_data_nofrag);
462 	}
463 
464 	rxrpc_tx_backoff(call, ret);
465 	if (ret == -EMSGSIZE)
466 		goto send_fragmentable;
467 
468 done:
469 	if (ret >= 0) {
470 		if (whdr.flags & RXRPC_REQUEST_ACK) {
471 			call->peer->rtt_last_req = skb->tstamp;
472 			if (call->peer->rtt_count > 1) {
473 				unsigned long nowj = jiffies, ack_lost_at;
474 
475 				ack_lost_at = rxrpc_get_rto_backoff(call->peer, false);
476 				ack_lost_at += nowj;
477 				WRITE_ONCE(call->ack_lost_at, ack_lost_at);
478 				rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
479 							rxrpc_timer_set_for_lost_ack);
480 			}
481 		}
482 
483 		if (sp->hdr.seq == 1 &&
484 		    !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
485 				      &call->flags)) {
486 			unsigned long nowj = jiffies, expect_rx_by;
487 
488 			expect_rx_by = nowj + call->next_rx_timo;
489 			WRITE_ONCE(call->expect_rx_by, expect_rx_by);
490 			rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
491 						rxrpc_timer_set_for_normal);
492 		}
493 
494 		rxrpc_set_keepalive(call);
495 	} else {
496 		/* Cancel the call if the initial transmission fails,
497 		 * particularly if that's due to network routing issues that
498 		 * aren't going away anytime soon.  The layer above can arrange
499 		 * the retransmission.
500 		 */
501 		if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags))
502 			rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
503 						  RX_USER_ABORT, ret);
504 	}
505 
506 	_leave(" = %d [%u]", ret, call->peer->maxdata);
507 	return ret;
508 
509 send_fragmentable:
510 	/* attempt to send this message with fragmentation enabled */
511 	_debug("send fragment");
512 
513 	down_write(&conn->params.local->defrag_sem);
514 
515 	sp->hdr.serial = serial;
516 	smp_wmb(); /* Set serial before timestamp */
517 	skb->tstamp = ktime_get_real();
518 	if (whdr.flags & RXRPC_REQUEST_ACK)
519 		rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
520 
521 	switch (conn->params.local->srx.transport.family) {
522 	case AF_INET6:
523 	case AF_INET:
524 		ip_sock_set_mtu_discover(conn->params.local->socket->sk,
525 				IP_PMTUDISC_DONT);
526 		ret = kernel_sendmsg(conn->params.local->socket, &msg,
527 				     iov, 2, len);
528 		conn->params.peer->last_tx_at = ktime_get_seconds();
529 
530 		ip_sock_set_mtu_discover(conn->params.local->socket->sk,
531 				IP_PMTUDISC_DO);
532 		break;
533 
534 	default:
535 		BUG();
536 	}
537 
538 	if (ret < 0) {
539 		rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
540 		trace_rxrpc_tx_fail(call->debug_id, serial, ret,
541 				    rxrpc_tx_point_call_data_frag);
542 	} else {
543 		trace_rxrpc_tx_packet(call->debug_id, &whdr,
544 				      rxrpc_tx_point_call_data_frag);
545 	}
546 	rxrpc_tx_backoff(call, ret);
547 
548 	up_write(&conn->params.local->defrag_sem);
549 	goto done;
550 }
551 
552 /*
553  * reject packets through the local endpoint
554  */
555 void rxrpc_reject_packets(struct rxrpc_local *local)
556 {
557 	struct sockaddr_rxrpc srx;
558 	struct rxrpc_skb_priv *sp;
559 	struct rxrpc_wire_header whdr;
560 	struct sk_buff *skb;
561 	struct msghdr msg;
562 	struct kvec iov[2];
563 	size_t size;
564 	__be32 code;
565 	int ret, ioc;
566 
567 	_enter("%d", local->debug_id);
568 
569 	iov[0].iov_base = &whdr;
570 	iov[0].iov_len = sizeof(whdr);
571 	iov[1].iov_base = &code;
572 	iov[1].iov_len = sizeof(code);
573 
574 	msg.msg_name = &srx.transport;
575 	msg.msg_control = NULL;
576 	msg.msg_controllen = 0;
577 	msg.msg_flags = 0;
578 
579 	memset(&whdr, 0, sizeof(whdr));
580 
581 	while ((skb = skb_dequeue(&local->reject_queue))) {
582 		rxrpc_see_skb(skb, rxrpc_skb_seen);
583 		sp = rxrpc_skb(skb);
584 
585 		switch (skb->mark) {
586 		case RXRPC_SKB_MARK_REJECT_BUSY:
587 			whdr.type = RXRPC_PACKET_TYPE_BUSY;
588 			size = sizeof(whdr);
589 			ioc = 1;
590 			break;
591 		case RXRPC_SKB_MARK_REJECT_ABORT:
592 			whdr.type = RXRPC_PACKET_TYPE_ABORT;
593 			code = htonl(skb->priority);
594 			size = sizeof(whdr) + sizeof(code);
595 			ioc = 2;
596 			break;
597 		default:
598 			rxrpc_free_skb(skb, rxrpc_skb_freed);
599 			continue;
600 		}
601 
602 		if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
603 			msg.msg_namelen = srx.transport_len;
604 
605 			whdr.epoch	= htonl(sp->hdr.epoch);
606 			whdr.cid	= htonl(sp->hdr.cid);
607 			whdr.callNumber	= htonl(sp->hdr.callNumber);
608 			whdr.serviceId	= htons(sp->hdr.serviceId);
609 			whdr.flags	= sp->hdr.flags;
610 			whdr.flags	^= RXRPC_CLIENT_INITIATED;
611 			whdr.flags	&= RXRPC_CLIENT_INITIATED;
612 
613 			ret = kernel_sendmsg(local->socket, &msg,
614 					     iov, ioc, size);
615 			if (ret < 0)
616 				trace_rxrpc_tx_fail(local->debug_id, 0, ret,
617 						    rxrpc_tx_point_reject);
618 			else
619 				trace_rxrpc_tx_packet(local->debug_id, &whdr,
620 						      rxrpc_tx_point_reject);
621 		}
622 
623 		rxrpc_free_skb(skb, rxrpc_skb_freed);
624 	}
625 
626 	_leave("");
627 }
628 
629 /*
630  * Send a VERSION reply to a peer as a keepalive.
631  */
632 void rxrpc_send_keepalive(struct rxrpc_peer *peer)
633 {
634 	struct rxrpc_wire_header whdr;
635 	struct msghdr msg;
636 	struct kvec iov[2];
637 	size_t len;
638 	int ret;
639 
640 	_enter("");
641 
642 	msg.msg_name	= &peer->srx.transport;
643 	msg.msg_namelen	= peer->srx.transport_len;
644 	msg.msg_control	= NULL;
645 	msg.msg_controllen = 0;
646 	msg.msg_flags	= 0;
647 
648 	whdr.epoch	= htonl(peer->local->rxnet->epoch);
649 	whdr.cid	= 0;
650 	whdr.callNumber	= 0;
651 	whdr.seq	= 0;
652 	whdr.serial	= 0;
653 	whdr.type	= RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
654 	whdr.flags	= RXRPC_LAST_PACKET;
655 	whdr.userStatus	= 0;
656 	whdr.securityIndex = 0;
657 	whdr._rsvd	= 0;
658 	whdr.serviceId	= 0;
659 
660 	iov[0].iov_base	= &whdr;
661 	iov[0].iov_len	= sizeof(whdr);
662 	iov[1].iov_base	= (char *)rxrpc_keepalive_string;
663 	iov[1].iov_len	= sizeof(rxrpc_keepalive_string);
664 
665 	len = iov[0].iov_len + iov[1].iov_len;
666 
667 	_proto("Tx VERSION (keepalive)");
668 
669 	ret = kernel_sendmsg(peer->local->socket, &msg, iov, 2, len);
670 	if (ret < 0)
671 		trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
672 				    rxrpc_tx_point_version_keepalive);
673 	else
674 		trace_rxrpc_tx_packet(peer->debug_id, &whdr,
675 				      rxrpc_tx_point_version_keepalive);
676 
677 	peer->last_tx_at = ktime_get_seconds();
678 	_leave("");
679 }
680