net/rxrpc/output.c

   1 /* RxRPC packet transmission
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/net.h>
  15 #include <linux/gfp.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/export.h>
  18 #include <net/sock.h>
  19 #include <net/af_rxrpc.h>
  20 #include "ar-internal.h"
  21
  22 struct rxrpc_ack_buffer {
  23         struct rxrpc_wire_header whdr;
  24         struct rxrpc_ackpacket ack;
  25         u8 acks[255];
  26         u8 pad[3];
  27         struct rxrpc_ackinfo ackinfo;
  28 };
  29
  30 struct rxrpc_abort_buffer {
  31         struct rxrpc_wire_header whdr;
  32         __be32 abort_code;
  33 };
  34
  35 static const char rxrpc_keepalive_string[] = "";
  36
  37 /*
  38  * Increase Tx backoff on transmission failure and clear it on success.
  39  */
  40 static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret)
  41 {
  42         if (ret < 0) {
  43                 u16 tx_backoff = READ_ONCE(call->tx_backoff);
  44
  45                 if (tx_backoff < HZ)
  46                         WRITE_ONCE(call->tx_backoff, tx_backoff + 1);
  47         } else {
  48                 WRITE_ONCE(call->tx_backoff, 0);
  49         }
  50 }
  51
  52 /*
  53  * Arrange for a keepalive ping a certain time after we last transmitted.  This
  54  * lets the far side know we're still interested in this call and helps keep
  55  * the route through any intervening firewall open.
  56  *
  57  * Receiving a response to the ping will prevent the ->expect_rx_by timer from
  58  * expiring.
  59  */
  60 static void rxrpc_set_keepalive(struct rxrpc_call *call)
  61 {
  62         unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
  63
  64         keepalive_at += now;
  65         WRITE_ONCE(call->keepalive_at, keepalive_at);
  66         rxrpc_reduce_call_timer(call, keepalive_at, now,
  67                                 rxrpc_timer_set_for_keepalive);
  68 }
  69
  70 /*
  71  * Fill out an ACK packet.
  72  */
  73 static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
  74                                  struct rxrpc_call *call,
  75                                  struct rxrpc_ack_buffer *pkt,
  76                                  rxrpc_seq_t *_hard_ack,
  77                                  rxrpc_seq_t *_top,
  78                                  u8 reason)
  79 {
  80         rxrpc_serial_t serial;
  81         rxrpc_seq_t hard_ack, top, seq;
  82         int ix;
  83         u32 mtu, jmax;
  84         u8 *ackp = pkt->acks;
  85
  86         /* Barrier against rxrpc_input_data(). */
  87         serial = call->ackr_serial;
  88         hard_ack = READ_ONCE(call->rx_hard_ack);
  89         top = smp_load_acquire(&call->rx_top);
  90         *_hard_ack = hard_ack;
  91         *_top = top;
  92
  93         pkt->ack.bufferSpace    = htons(8);
  94         pkt->ack.maxSkew        = htons(call->ackr_skew);
  95         pkt->ack.firstPacket    = htonl(hard_ack + 1);
  96         pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
  97         pkt->ack.serial         = htonl(serial);
  98         pkt->ack.reason         = reason;
  99         pkt->ack.nAcks          = top - hard_ack;
 100
 101         if (reason == RXRPC_ACK_PING)
 102                 pkt->whdr.flags |= RXRPC_REQUEST_ACK;
 103
 104         if (after(top, hard_ack)) {
 105                 seq = hard_ack + 1;
 106                 do {
 107                         ix = seq & RXRPC_RXTX_BUFF_MASK;
 108                         if (call->rxtx_buffer[ix])
 109                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
 110                         else
 111                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
 112                         seq++;
 113                 } while (before_eq(seq, top));
 114         }
 115
 116         mtu = conn->params.peer->if_mtu;
 117         mtu -= conn->params.peer->hdrsize;
 118         jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
 119         pkt->ackinfo.rxMTU      = htonl(rxrpc_rx_mtu);
 120         pkt->ackinfo.maxMTU     = htonl(mtu);
 121         pkt->ackinfo.rwind      = htonl(call->rx_winsize);
 122         pkt->ackinfo.jumbo_max  = htonl(jmax);
 123
 124         *ackp++ = 0;
 125         *ackp++ = 0;
 126         *ackp++ = 0;
 127         return top - hard_ack + 3;
 128 }
 129
 130 /*
 131  * Send an ACK call packet.
 132  */
 133 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
 134                           rxrpc_serial_t *_serial)
 135 {
 136         struct rxrpc_connection *conn;
 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  */
 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  */
 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  */
 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  */
 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 }