Merge tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave...
[linux-2.6-microblaze.git] / net / rxrpc / output.c
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         rxrpc_seq_t hard_ack, top, seq;
78         int ix;
79         u32 mtu, jmax;
80         u8 *ackp = pkt->acks;
81
82         /* Barrier against rxrpc_input_data(). */
83         serial = call->ackr_serial;
84         hard_ack = READ_ONCE(call->rx_hard_ack);
85         top = smp_load_acquire(&call->rx_top);
86         *_hard_ack = hard_ack;
87         *_top = top;
88
89         pkt->ack.bufferSpace    = htons(8);
90         pkt->ack.maxSkew        = htons(0);
91         pkt->ack.firstPacket    = htonl(hard_ack + 1);
92         pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
93         pkt->ack.serial         = htonl(serial);
94         pkt->ack.reason         = reason;
95         pkt->ack.nAcks          = top - hard_ack;
96
97         if (reason == RXRPC_ACK_PING)
98                 pkt->whdr.flags |= RXRPC_REQUEST_ACK;
99
100         if (after(top, hard_ack)) {
101                 seq = hard_ack + 1;
102                 do {
103                         ix = seq & RXRPC_RXTX_BUFF_MASK;
104                         if (call->rxtx_buffer[ix])
105                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
106                         else
107                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
108                         seq++;
109                 } while (before_eq(seq, top));
110         }
111
112         mtu = conn->params.peer->if_mtu;
113         mtu -= conn->params.peer->hdrsize;
114         jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
115         pkt->ackinfo.rxMTU      = htonl(rxrpc_rx_mtu);
116         pkt->ackinfo.maxMTU     = htonl(mtu);
117         pkt->ackinfo.rwind      = htonl(call->rx_winsize);
118         pkt->ackinfo.jumbo_max  = htonl(jmax);
119
120         *ackp++ = 0;
121         *ackp++ = 0;
122         *ackp++ = 0;
123         return top - hard_ack + 3;
124 }
125
126 /*
127  * Record the beginning of an RTT probe.
128  */
129 static int rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial,
130                                  enum rxrpc_rtt_tx_trace why)
131 {
132         unsigned long avail = call->rtt_avail;
133         int rtt_slot = 9;
134
135         if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK))
136                 goto no_slot;
137
138         rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK);
139         if (!test_and_clear_bit(rtt_slot, &call->rtt_avail))
140                 goto no_slot;
141
142         call->rtt_serial[rtt_slot] = serial;
143         call->rtt_sent_at[rtt_slot] = ktime_get_real();
144         smp_wmb(); /* Write data before avail bit */
145         set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
146
147         trace_rxrpc_rtt_tx(call, why, rtt_slot, serial);
148         return rtt_slot;
149
150 no_slot:
151         trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial);
152         return -1;
153 }
154
155 /*
156  * Cancel an RTT probe.
157  */
158 static void rxrpc_cancel_rtt_probe(struct rxrpc_call *call,
159                                    rxrpc_serial_t serial, int rtt_slot)
160 {
161         if (rtt_slot != -1) {
162                 clear_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
163                 smp_wmb(); /* Clear pending bit before setting slot */
164                 set_bit(rtt_slot, &call->rtt_avail);
165                 trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_cancel, rtt_slot, serial);
166         }
167 }
168
169 /*
170  * Send an ACK call packet.
171  */
172 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
173                           rxrpc_serial_t *_serial)
174 {
175         struct rxrpc_connection *conn;
176         struct rxrpc_ack_buffer *pkt;
177         struct msghdr msg;
178         struct kvec iov[2];
179         rxrpc_serial_t serial;
180         rxrpc_seq_t hard_ack, top;
181         size_t len, n;
182         int ret, rtt_slot = -1;
183         u8 reason;
184
185         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
186                 return -ECONNRESET;
187
188         pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
189         if (!pkt)
190                 return -ENOMEM;
191
192         conn = call->conn;
193
194         msg.msg_name    = &call->peer->srx.transport;
195         msg.msg_namelen = call->peer->srx.transport_len;
196         msg.msg_control = NULL;
197         msg.msg_controllen = 0;
198         msg.msg_flags   = 0;
199
200         pkt->whdr.epoch         = htonl(conn->proto.epoch);
201         pkt->whdr.cid           = htonl(call->cid);
202         pkt->whdr.callNumber    = htonl(call->call_id);
203         pkt->whdr.seq           = 0;
204         pkt->whdr.type          = RXRPC_PACKET_TYPE_ACK;
205         pkt->whdr.flags         = RXRPC_SLOW_START_OK | conn->out_clientflag;
206         pkt->whdr.userStatus    = 0;
207         pkt->whdr.securityIndex = call->security_ix;
208         pkt->whdr._rsvd         = 0;
209         pkt->whdr.serviceId     = htons(call->service_id);
210
211         spin_lock_bh(&call->lock);
212         if (ping) {
213                 reason = RXRPC_ACK_PING;
214         } else {
215                 reason = call->ackr_reason;
216                 if (!call->ackr_reason) {
217                         spin_unlock_bh(&call->lock);
218                         ret = 0;
219                         goto out;
220                 }
221                 call->ackr_reason = 0;
222         }
223         n = rxrpc_fill_out_ack(conn, call, pkt, &hard_ack, &top, reason);
224
225         spin_unlock_bh(&call->lock);
226
227         iov[0].iov_base = pkt;
228         iov[0].iov_len  = sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
229         iov[1].iov_base = &pkt->ackinfo;
230         iov[1].iov_len  = sizeof(pkt->ackinfo);
231         len = iov[0].iov_len + iov[1].iov_len;
232
233         serial = atomic_inc_return(&conn->serial);
234         pkt->whdr.serial = htonl(serial);
235         trace_rxrpc_tx_ack(call->debug_id, serial,
236                            ntohl(pkt->ack.firstPacket),
237                            ntohl(pkt->ack.serial),
238                            pkt->ack.reason, pkt->ack.nAcks);
239         if (_serial)
240                 *_serial = serial;
241
242         if (ping)
243                 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_ping);
244
245         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
246         conn->params.peer->last_tx_at = ktime_get_seconds();
247         if (ret < 0)
248                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
249                                     rxrpc_tx_point_call_ack);
250         else
251                 trace_rxrpc_tx_packet(call->debug_id, &pkt->whdr,
252                                       rxrpc_tx_point_call_ack);
253         rxrpc_tx_backoff(call, ret);
254
255         if (call->state < RXRPC_CALL_COMPLETE) {
256                 if (ret < 0) {
257                         rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
258                         rxrpc_propose_ACK(call, pkt->ack.reason,
259                                           ntohl(pkt->ack.serial),
260                                           false, true,
261                                           rxrpc_propose_ack_retry_tx);
262                 } else {
263                         spin_lock_bh(&call->lock);
264                         if (after(hard_ack, call->ackr_consumed))
265                                 call->ackr_consumed = hard_ack;
266                         if (after(top, call->ackr_seen))
267                                 call->ackr_seen = top;
268                         spin_unlock_bh(&call->lock);
269                 }
270
271                 rxrpc_set_keepalive(call);
272         }
273
274 out:
275         kfree(pkt);
276         return ret;
277 }
278
279 /*
280  * Send an ABORT call packet.
281  */
282 int rxrpc_send_abort_packet(struct rxrpc_call *call)
283 {
284         struct rxrpc_connection *conn;
285         struct rxrpc_abort_buffer pkt;
286         struct msghdr msg;
287         struct kvec iov[1];
288         rxrpc_serial_t serial;
289         int ret;
290
291         /* Don't bother sending aborts for a client call once the server has
292          * hard-ACK'd all of its request data.  After that point, we're not
293          * going to stop the operation proceeding, and whilst we might limit
294          * the reply, it's not worth it if we can send a new call on the same
295          * channel instead, thereby closing off this call.
296          */
297         if (rxrpc_is_client_call(call) &&
298             test_bit(RXRPC_CALL_TX_LAST, &call->flags))
299                 return 0;
300
301         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
302                 return -ECONNRESET;
303
304         conn = call->conn;
305
306         msg.msg_name    = &call->peer->srx.transport;
307         msg.msg_namelen = call->peer->srx.transport_len;
308         msg.msg_control = NULL;
309         msg.msg_controllen = 0;
310         msg.msg_flags   = 0;
311
312         pkt.whdr.epoch          = htonl(conn->proto.epoch);
313         pkt.whdr.cid            = htonl(call->cid);
314         pkt.whdr.callNumber     = htonl(call->call_id);
315         pkt.whdr.seq            = 0;
316         pkt.whdr.type           = RXRPC_PACKET_TYPE_ABORT;
317         pkt.whdr.flags          = conn->out_clientflag;
318         pkt.whdr.userStatus     = 0;
319         pkt.whdr.securityIndex  = call->security_ix;
320         pkt.whdr._rsvd          = 0;
321         pkt.whdr.serviceId      = htons(call->service_id);
322         pkt.abort_code          = htonl(call->abort_code);
323
324         iov[0].iov_base = &pkt;
325         iov[0].iov_len  = sizeof(pkt);
326
327         serial = atomic_inc_return(&conn->serial);
328         pkt.whdr.serial = htonl(serial);
329
330         ret = kernel_sendmsg(conn->params.local->socket,
331                              &msg, iov, 1, sizeof(pkt));
332         conn->params.peer->last_tx_at = ktime_get_seconds();
333         if (ret < 0)
334                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
335                                     rxrpc_tx_point_call_abort);
336         else
337                 trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
338                                       rxrpc_tx_point_call_abort);
339         rxrpc_tx_backoff(call, ret);
340         return ret;
341 }
342
343 /*
344  * send a packet through the transport endpoint
345  */
346 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
347                            bool retrans)
348 {
349         struct rxrpc_connection *conn = call->conn;
350         struct rxrpc_wire_header whdr;
351         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
352         struct msghdr msg;
353         struct kvec iov[2];
354         rxrpc_serial_t serial;
355         size_t len;
356         int ret, rtt_slot = -1;
357
358         _enter(",{%d}", skb->len);
359
360         if (hlist_unhashed(&call->error_link)) {
361                 spin_lock_bh(&call->peer->lock);
362                 hlist_add_head_rcu(&call->error_link, &call->peer->error_targets);
363                 spin_unlock_bh(&call->peer->lock);
364         }
365
366         /* Each transmission of a Tx packet needs a new serial number */
367         serial = atomic_inc_return(&conn->serial);
368
369         whdr.epoch      = htonl(conn->proto.epoch);
370         whdr.cid        = htonl(call->cid);
371         whdr.callNumber = htonl(call->call_id);
372         whdr.seq        = htonl(sp->hdr.seq);
373         whdr.serial     = htonl(serial);
374         whdr.type       = RXRPC_PACKET_TYPE_DATA;
375         whdr.flags      = sp->hdr.flags;
376         whdr.userStatus = 0;
377         whdr.securityIndex = call->security_ix;
378         whdr._rsvd      = htons(sp->hdr._rsvd);
379         whdr.serviceId  = htons(call->service_id);
380
381         if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
382             sp->hdr.seq == 1)
383                 whdr.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
384
385         iov[0].iov_base = &whdr;
386         iov[0].iov_len = sizeof(whdr);
387         iov[1].iov_base = skb->head;
388         iov[1].iov_len = skb->len;
389         len = iov[0].iov_len + iov[1].iov_len;
390
391         msg.msg_name = &call->peer->srx.transport;
392         msg.msg_namelen = call->peer->srx.transport_len;
393         msg.msg_control = NULL;
394         msg.msg_controllen = 0;
395         msg.msg_flags = 0;
396
397         /* If our RTT cache needs working on, request an ACK.  Also request
398          * ACKs if a DATA packet appears to have been lost.
399          *
400          * However, we mustn't request an ACK on the last reply packet of a
401          * service call, lest OpenAFS incorrectly send us an ACK with some
402          * soft-ACKs in it and then never follow up with a proper hard ACK.
403          */
404         if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) ||
405              rxrpc_to_server(sp)
406              ) &&
407             (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||
408              retrans ||
409              call->cong_mode == RXRPC_CALL_SLOW_START ||
410              (call->peer->rtt_count < 3 && sp->hdr.seq & 1) ||
411              ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
412                           ktime_get_real())))
413                 whdr.flags |= RXRPC_REQUEST_ACK;
414
415         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
416                 static int lose;
417                 if ((lose++ & 7) == 7) {
418                         ret = 0;
419                         trace_rxrpc_tx_data(call, sp->hdr.seq, serial,
420                                             whdr.flags, retrans, true);
421                         goto done;
422                 }
423         }
424
425         trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, retrans,
426                             false);
427
428         /* send the packet with the don't fragment bit set if we currently
429          * think it's small enough */
430         if (iov[1].iov_len >= call->peer->maxdata)
431                 goto send_fragmentable;
432
433         down_read(&conn->params.local->defrag_sem);
434
435         sp->hdr.serial = serial;
436         smp_wmb(); /* Set serial before timestamp */
437         skb->tstamp = ktime_get_real();
438         if (whdr.flags & RXRPC_REQUEST_ACK)
439                 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
440
441         /* send the packet by UDP
442          * - returns -EMSGSIZE if UDP would have to fragment the packet
443          *   to go out of the interface
444          *   - in which case, we'll have processed the ICMP error
445          *     message and update the peer record
446          */
447         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
448         conn->params.peer->last_tx_at = ktime_get_seconds();
449
450         up_read(&conn->params.local->defrag_sem);
451         if (ret < 0) {
452                 rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
453                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
454                                     rxrpc_tx_point_call_data_nofrag);
455         } else {
456                 trace_rxrpc_tx_packet(call->debug_id, &whdr,
457                                       rxrpc_tx_point_call_data_nofrag);
458         }
459
460         rxrpc_tx_backoff(call, ret);
461         if (ret == -EMSGSIZE)
462                 goto send_fragmentable;
463
464 done:
465         if (ret >= 0) {
466                 if (whdr.flags & RXRPC_REQUEST_ACK) {
467                         call->peer->rtt_last_req = skb->tstamp;
468                         if (call->peer->rtt_count > 1) {
469                                 unsigned long nowj = jiffies, ack_lost_at;
470
471                                 ack_lost_at = rxrpc_get_rto_backoff(call->peer, retrans);
472                                 ack_lost_at += nowj;
473                                 WRITE_ONCE(call->ack_lost_at, ack_lost_at);
474                                 rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
475                                                         rxrpc_timer_set_for_lost_ack);
476                         }
477                 }
478
479                 if (sp->hdr.seq == 1 &&
480                     !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
481                                       &call->flags)) {
482                         unsigned long nowj = jiffies, expect_rx_by;
483
484                         expect_rx_by = nowj + call->next_rx_timo;
485                         WRITE_ONCE(call->expect_rx_by, expect_rx_by);
486                         rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
487                                                 rxrpc_timer_set_for_normal);
488                 }
489
490                 rxrpc_set_keepalive(call);
491         } else {
492                 /* Cancel the call if the initial transmission fails,
493                  * particularly if that's due to network routing issues that
494                  * aren't going away anytime soon.  The layer above can arrange
495                  * the retransmission.
496                  */
497                 if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags))
498                         rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
499                                                   RX_USER_ABORT, ret);
500         }
501
502         _leave(" = %d [%u]", ret, call->peer->maxdata);
503         return ret;
504
505 send_fragmentable:
506         /* attempt to send this message with fragmentation enabled */
507         _debug("send fragment");
508
509         down_write(&conn->params.local->defrag_sem);
510
511         sp->hdr.serial = serial;
512         smp_wmb(); /* Set serial before timestamp */
513         skb->tstamp = ktime_get_real();
514         if (whdr.flags & RXRPC_REQUEST_ACK)
515                 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
516
517         switch (conn->params.local->srx.transport.family) {
518         case AF_INET6:
519         case AF_INET:
520                 ip_sock_set_mtu_discover(conn->params.local->socket->sk,
521                                 IP_PMTUDISC_DONT);
522                 ret = kernel_sendmsg(conn->params.local->socket, &msg,
523                                      iov, 2, len);
524                 conn->params.peer->last_tx_at = ktime_get_seconds();
525
526                 ip_sock_set_mtu_discover(conn->params.local->socket->sk,
527                                 IP_PMTUDISC_DO);
528                 break;
529
530         default:
531                 BUG();
532         }
533
534         if (ret < 0) {
535                 rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
536                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
537                                     rxrpc_tx_point_call_data_frag);
538         } else {
539                 trace_rxrpc_tx_packet(call->debug_id, &whdr,
540                                       rxrpc_tx_point_call_data_frag);
541         }
542         rxrpc_tx_backoff(call, ret);
543
544         up_write(&conn->params.local->defrag_sem);
545         goto done;
546 }
547
548 /*
549  * reject packets through the local endpoint
550  */
551 void rxrpc_reject_packets(struct rxrpc_local *local)
552 {
553         struct sockaddr_rxrpc srx;
554         struct rxrpc_skb_priv *sp;
555         struct rxrpc_wire_header whdr;
556         struct sk_buff *skb;
557         struct msghdr msg;
558         struct kvec iov[2];
559         size_t size;
560         __be32 code;
561         int ret, ioc;
562
563         _enter("%d", local->debug_id);
564
565         iov[0].iov_base = &whdr;
566         iov[0].iov_len = sizeof(whdr);
567         iov[1].iov_base = &code;
568         iov[1].iov_len = sizeof(code);
569
570         msg.msg_name = &srx.transport;
571         msg.msg_control = NULL;
572         msg.msg_controllen = 0;
573         msg.msg_flags = 0;
574
575         memset(&whdr, 0, sizeof(whdr));
576
577         while ((skb = skb_dequeue(&local->reject_queue))) {
578                 rxrpc_see_skb(skb, rxrpc_skb_seen);
579                 sp = rxrpc_skb(skb);
580
581                 switch (skb->mark) {
582                 case RXRPC_SKB_MARK_REJECT_BUSY:
583                         whdr.type = RXRPC_PACKET_TYPE_BUSY;
584                         size = sizeof(whdr);
585                         ioc = 1;
586                         break;
587                 case RXRPC_SKB_MARK_REJECT_ABORT:
588                         whdr.type = RXRPC_PACKET_TYPE_ABORT;
589                         code = htonl(skb->priority);
590                         size = sizeof(whdr) + sizeof(code);
591                         ioc = 2;
592                         break;
593                 default:
594                         rxrpc_free_skb(skb, rxrpc_skb_freed);
595                         continue;
596                 }
597
598                 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
599                         msg.msg_namelen = srx.transport_len;
600
601                         whdr.epoch      = htonl(sp->hdr.epoch);
602                         whdr.cid        = htonl(sp->hdr.cid);
603                         whdr.callNumber = htonl(sp->hdr.callNumber);
604                         whdr.serviceId  = htons(sp->hdr.serviceId);
605                         whdr.flags      = sp->hdr.flags;
606                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
607                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
608
609                         ret = kernel_sendmsg(local->socket, &msg,
610                                              iov, ioc, size);
611                         if (ret < 0)
612                                 trace_rxrpc_tx_fail(local->debug_id, 0, ret,
613                                                     rxrpc_tx_point_reject);
614                         else
615                                 trace_rxrpc_tx_packet(local->debug_id, &whdr,
616                                                       rxrpc_tx_point_reject);
617                 }
618
619                 rxrpc_free_skb(skb, rxrpc_skb_freed);
620         }
621
622         _leave("");
623 }
624
625 /*
626  * Send a VERSION reply to a peer as a keepalive.
627  */
628 void rxrpc_send_keepalive(struct rxrpc_peer *peer)
629 {
630         struct rxrpc_wire_header whdr;
631         struct msghdr msg;
632         struct kvec iov[2];
633         size_t len;
634         int ret;
635
636         _enter("");
637
638         msg.msg_name    = &peer->srx.transport;
639         msg.msg_namelen = peer->srx.transport_len;
640         msg.msg_control = NULL;
641         msg.msg_controllen = 0;
642         msg.msg_flags   = 0;
643
644         whdr.epoch      = htonl(peer->local->rxnet->epoch);
645         whdr.cid        = 0;
646         whdr.callNumber = 0;
647         whdr.seq        = 0;
648         whdr.serial     = 0;
649         whdr.type       = RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
650         whdr.flags      = RXRPC_LAST_PACKET;
651         whdr.userStatus = 0;
652         whdr.securityIndex = 0;
653         whdr._rsvd      = 0;
654         whdr.serviceId  = 0;
655
656         iov[0].iov_base = &whdr;
657         iov[0].iov_len  = sizeof(whdr);
658         iov[1].iov_base = (char *)rxrpc_keepalive_string;
659         iov[1].iov_len  = sizeof(rxrpc_keepalive_string);
660
661         len = iov[0].iov_len + iov[1].iov_len;
662
663         _proto("Tx VERSION (keepalive)");
664
665         ret = kernel_sendmsg(peer->local->socket, &msg, iov, 2, len);
666         if (ret < 0)
667                 trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
668                                     rxrpc_tx_point_version_keepalive);
669         else
670                 trace_rxrpc_tx_packet(peer->debug_id, &whdr,
671                                       rxrpc_tx_point_version_keepalive);
672
673         peer->last_tx_at = ktime_get_seconds();
674         _leave("");
675 }