root/net/rxrpc/output.c

DEFINITIONS

1. rxrpc_tx_backoff
2. rxrpc_set_keepalive
3. rxrpc_fill_out_ack
4. rxrpc_send_ack_packet
5. rxrpc_send_abort_packet
6. rxrpc_send_data_packet
7. rxrpc_reject_packets
8. rxrpc_send_keepalive

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