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         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(0);
  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  * Send an ACK call packet.
 135  */
 136 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
 137                           rxrpc_serial_t *_serial)
 138 {
 139         struct rxrpc_connection *conn;
 140         struct rxrpc_ack_buffer *pkt;
 141         struct msghdr msg;
 142         struct kvec iov[2];
 143         rxrpc_serial_t serial;
 144         rxrpc_seq_t hard_ack, top;
 145         size_t len, n;
 146         int ret;
 147         u8 reason;
 148
 149         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
 150                 return -ECONNRESET;
 151
 152         pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 153         if (!pkt)
 154                 return -ENOMEM;
 155
 156         conn = call->conn;
 157
 158         msg.msg_name    = &call->peer->srx.transport;
 159         msg.msg_namelen = call->peer->srx.transport_len;
 160         msg.msg_control = NULL;
 161         msg.msg_controllen = 0;
 162         msg.msg_flags   = 0;
 163
 164         pkt->whdr.epoch         = htonl(conn->proto.epoch);
 165         pkt->whdr.cid           = htonl(call->cid);
 166         pkt->whdr.callNumber    = htonl(call->call_id);
 167         pkt->whdr.seq           = 0;
 168         pkt->whdr.type          = RXRPC_PACKET_TYPE_ACK;
 169         pkt->whdr.flags         = RXRPC_SLOW_START_OK | conn->out_clientflag;
 170         pkt->whdr.userStatus    = 0;
 171         pkt->whdr.securityIndex = call->security_ix;
 172         pkt->whdr._rsvd         = 0;
 173         pkt->whdr.serviceId     = htons(call->service_id);
 174
 175         spin_lock_bh(&call->lock);
 176         if (ping) {
 177                 reason = RXRPC_ACK_PING;
 178         } else {
 179                 reason = call->ackr_reason;
 180                 if (!call->ackr_reason) {
 181                         spin_unlock_bh(&call->lock);
 182                         ret = 0;
 183                         goto out;
 184                 }
 185                 call->ackr_reason = 0;
 186         }
 187         n = rxrpc_fill_out_ack(conn, call, pkt, &hard_ack, &top, reason);
 188
 189         spin_unlock_bh(&call->lock);
 190         if (n == 0) {
 191                 kfree(pkt);
 192                 return 0;
 193         }
 194
 195         iov[0].iov_base = pkt;
 196         iov[0].iov_len  = sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
 197         iov[1].iov_base = &pkt->ackinfo;
 198         iov[1].iov_len  = sizeof(pkt->ackinfo);
 199         len = iov[0].iov_len + iov[1].iov_len;
 200
 201         serial = atomic_inc_return(&conn->serial);
 202         pkt->whdr.serial = htonl(serial);
 203         trace_rxrpc_tx_ack(call->debug_id, serial,
 204                            ntohl(pkt->ack.firstPacket),
 205                            ntohl(pkt->ack.serial),
 206                            pkt->ack.reason, pkt->ack.nAcks);
 207         if (_serial)
 208                 *_serial = serial;
 209
 210         if (ping) {
 211                 call->ping_serial = serial;
 212                 smp_wmb();
 213                 /* We need to stick a time in before we send the packet in case
 214                  * the reply gets back before kernel_sendmsg() completes - but
 215                  * asking UDP to send the packet can take a relatively long
 216                  * time.
 217                  */
 218                 call->ping_time = ktime_get_real();
 219                 set_bit(RXRPC_CALL_PINGING, &call->flags);
 220                 trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
 221         }
 222
 223         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 224         conn->params.peer->last_tx_at = ktime_get_seconds();
 225         if (ret < 0)
 226                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 227                                     rxrpc_tx_point_call_ack);
 228         else
 229                 trace_rxrpc_tx_packet(call->debug_id, &pkt->whdr,
 230                                       rxrpc_tx_point_call_ack);
 231         rxrpc_tx_backoff(call, ret);
 232
 233         if (call->state < RXRPC_CALL_COMPLETE) {
 234                 if (ret < 0) {
 235                         if (ping)
 236                                 clear_bit(RXRPC_CALL_PINGING, &call->flags);
 237                         rxrpc_propose_ACK(call, pkt->ack.reason,
 238                                           ntohl(pkt->ack.serial),
 239                                           false, true,
 240                                           rxrpc_propose_ack_retry_tx);
 241                 }
 242
 243                 rxrpc_set_keepalive(call);
 244         }
 245
 246 out:
 247         kfree(pkt);
 248         return ret;
 249 }
 250
 251 /*
 252  * Send an ABORT call packet.
 253  */
 254 int rxrpc_send_abort_packet(struct rxrpc_call *call)
 255 {
 256         struct rxrpc_connection *conn;
 257         struct rxrpc_abort_buffer pkt;
 258         struct msghdr msg;
 259         struct kvec iov[1];
 260         rxrpc_serial_t serial;
 261         int ret;
 262
 263         /* Don't bother sending aborts for a client call once the server has
 264          * hard-ACK'd all of its request data.  After that point, we're not
 265          * going to stop the operation proceeding, and whilst we might limit
 266          * the reply, it's not worth it if we can send a new call on the same
 267          * channel instead, thereby closing off this call.
 268          */
 269         if (rxrpc_is_client_call(call) &&
 270             test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 271                 return 0;
 272
 273         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
 274                 return -ECONNRESET;
 275
 276         conn = call->conn;
 277
 278         msg.msg_name    = &call->peer->srx.transport;
 279         msg.msg_namelen = call->peer->srx.transport_len;
 280         msg.msg_control = NULL;
 281         msg.msg_controllen = 0;
 282         msg.msg_flags   = 0;
 283
 284         pkt.whdr.epoch          = htonl(conn->proto.epoch);
 285         pkt.whdr.cid            = htonl(call->cid);
 286         pkt.whdr.callNumber     = htonl(call->call_id);
 287         pkt.whdr.seq            = 0;
 288         pkt.whdr.type           = RXRPC_PACKET_TYPE_ABORT;
 289         pkt.whdr.flags          = conn->out_clientflag;
 290         pkt.whdr.userStatus     = 0;
 291         pkt.whdr.securityIndex  = call->security_ix;
 292         pkt.whdr._rsvd          = 0;
 293         pkt.whdr.serviceId      = htons(call->service_id);
 294         pkt.abort_code          = htonl(call->abort_code);
 295
 296         iov[0].iov_base = &pkt;
 297         iov[0].iov_len  = sizeof(pkt);
 298
 299         serial = atomic_inc_return(&conn->serial);
 300         pkt.whdr.serial = htonl(serial);
 301
 302         ret = kernel_sendmsg(conn->params.local->socket,
 303                              &msg, iov, 1, sizeof(pkt));
 304         conn->params.peer->last_tx_at = ktime_get_seconds();
 305         if (ret < 0)
 306                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 307                                     rxrpc_tx_point_call_abort);
 308         else
 309                 trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
 310                                       rxrpc_tx_point_call_abort);
 311         rxrpc_tx_backoff(call, ret);
 312         return ret;
 313 }
 314
 315 /*
 316  * send a packet through the transport endpoint
 317  */
 318 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 319                            bool retrans)
 320 {
 321         struct rxrpc_connection *conn = call->conn;
 322         struct rxrpc_wire_header whdr;
 323         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 324         struct msghdr msg;
 325         struct kvec iov[2];
 326         rxrpc_serial_t serial;
 327         size_t len;
 328         int ret, opt;
 329
 330         _enter(",{%d}", skb->len);
 331
 332         /* Each transmission of a Tx packet needs a new serial number */
 333         serial = atomic_inc_return(&conn->serial);
 334
 335         whdr.epoch      = htonl(conn->proto.epoch);
 336         whdr.cid        = htonl(call->cid);
 337         whdr.callNumber = htonl(call->call_id);
 338         whdr.seq        = htonl(sp->hdr.seq);
 339         whdr.serial     = htonl(serial);
 340         whdr.type       = RXRPC_PACKET_TYPE_DATA;
 341         whdr.flags      = sp->hdr.flags;
 342         whdr.userStatus = 0;
 343         whdr.securityIndex = call->security_ix;
 344         whdr._rsvd      = htons(sp->hdr._rsvd);
 345         whdr.serviceId  = htons(call->service_id);
 346
 347         if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
 348             sp->hdr.seq == 1)
 349                 whdr.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
 350
 351         iov[0].iov_base = &whdr;
 352         iov[0].iov_len = sizeof(whdr);
 353         iov[1].iov_base = skb->head;
 354         iov[1].iov_len = skb->len;
 355         len = iov[0].iov_len + iov[1].iov_len;
 356
 357         msg.msg_name = &call->peer->srx.transport;
 358         msg.msg_namelen = call->peer->srx.transport_len;
 359         msg.msg_control = NULL;
 360         msg.msg_controllen = 0;
 361         msg.msg_flags = 0;
 362
 363         /* If our RTT cache needs working on, request an ACK.  Also request
 364          * ACKs if a DATA packet appears to have been lost.
 365          *
 366          * However, we mustn't request an ACK on the last reply packet of a
 367          * service call, lest OpenAFS incorrectly send us an ACK with some
 368          * soft-ACKs in it and then never follow up with a proper hard ACK.
 369          */
 370         if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) ||
 371              rxrpc_to_server(sp)
 372              ) &&
 373             (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||
 374              retrans ||
 375              call->cong_mode == RXRPC_CALL_SLOW_START ||
 376              (call->peer->rtt_count < 3 && sp->hdr.seq & 1) ||
 377              ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
 378                           ktime_get_real())))
 379                 whdr.flags |= RXRPC_REQUEST_ACK;
 380
 381         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 382                 static int lose;
 383                 if ((lose++ & 7) == 7) {
 384                         ret = 0;
 385                         trace_rxrpc_tx_data(call, sp->hdr.seq, serial,
 386                                             whdr.flags, retrans, true);
 387                         goto done;
 388                 }
 389         }
 390
 391         trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, retrans,
 392                             false);
 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         if (ret >= 0) {
 427                 if (whdr.flags & RXRPC_REQUEST_ACK) {
 428                         call->peer->rtt_last_req = skb->tstamp;
 429                         trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
 430                         if (call->peer->rtt_count > 1) {
 431                                 unsigned long nowj = jiffies, ack_lost_at;
 432
 433                                 ack_lost_at = rxrpc_get_rto_backoff(call->peer, false);
 434                                 ack_lost_at += nowj;
 435                                 WRITE_ONCE(call->ack_lost_at, ack_lost_at);
 436                                 rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
 437                                                         rxrpc_timer_set_for_lost_ack);
 438                         }
 439                 }
 440
 441                 if (sp->hdr.seq == 1 &&
 442                     !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
 443                                       &call->flags)) {
 444                         unsigned long nowj = jiffies, expect_rx_by;
 445
 446                         expect_rx_by = nowj + call->next_rx_timo;
 447                         WRITE_ONCE(call->expect_rx_by, expect_rx_by);
 448                         rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
 449                                                 rxrpc_timer_set_for_normal);
 450                 }
 451
 452                 rxrpc_set_keepalive(call);
 453         } else {
 454                 /* Cancel the call if the initial transmission fails,
 455                  * particularly if that's due to network routing issues that
 456                  * aren't going away anytime soon.  The layer above can arrange
 457                  * the retransmission.
 458                  */
 459                 if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags))
 460                         rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
 461                                                   RX_USER_ABORT, ret);
 462         }
 463
 464         _leave(" = %d [%u]", ret, call->peer->maxdata);
 465         return ret;
 466
 467 send_fragmentable:
 468         /* attempt to send this message with fragmentation enabled */
 469         _debug("send fragment");
 470
 471         down_write(&conn->params.local->defrag_sem);
 472
 473         sp->hdr.serial = serial;
 474         smp_wmb(); /* Set serial before timestamp */
 475         skb->tstamp = ktime_get_real();
 476
 477         switch (conn->params.local->srx.transport.family) {
 478         case AF_INET6:
 479         case AF_INET:
 480                 opt = IP_PMTUDISC_DONT;
 481                 kernel_setsockopt(conn->params.local->socket,
 482                                   SOL_IP, IP_MTU_DISCOVER,
 483                                   (char *)&opt, sizeof(opt));
 484                 ret = kernel_sendmsg(conn->params.local->socket, &msg,
 485                                      iov, 2, len);
 486                 conn->params.peer->last_tx_at = ktime_get_seconds();
 487
 488                 opt = IP_PMTUDISC_DO;
 489                 kernel_setsockopt(conn->params.local->socket,
 490                                   SOL_IP, IP_MTU_DISCOVER,
 491                                   (char *)&opt, sizeof(opt));
 492                 break;
 493
 494         default:
 495                 BUG();
 496         }
 497
 498         if (ret < 0)
 499                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 500                                     rxrpc_tx_point_call_data_frag);
 501         else
 502                 trace_rxrpc_tx_packet(call->debug_id, &whdr,
 503                                       rxrpc_tx_point_call_data_frag);
 504         rxrpc_tx_backoff(call, ret);
 505
 506         up_write(&conn->params.local->defrag_sem);
 507         goto done;
 508 }
 509
 510 /*
 511  * reject packets through the local endpoint
 512  */
 513 void rxrpc_reject_packets(struct rxrpc_local *local)
 514 {
 515         struct sockaddr_rxrpc srx;
 516         struct rxrpc_skb_priv *sp;
 517         struct rxrpc_wire_header whdr;
 518         struct sk_buff *skb;
 519         struct msghdr msg;
 520         struct kvec iov[2];
 521         size_t size;
 522         __be32 code;
 523         int ret, ioc;
 524
 525         _enter("%d", local->debug_id);
 526
 527         iov[0].iov_base = &whdr;
 528         iov[0].iov_len = sizeof(whdr);
 529         iov[1].iov_base = &code;
 530         iov[1].iov_len = sizeof(code);
 531
 532         msg.msg_name = &srx.transport;
 533         msg.msg_control = NULL;
 534         msg.msg_controllen = 0;
 535         msg.msg_flags = 0;
 536
 537         memset(&whdr, 0, sizeof(whdr));
 538
 539         while ((skb = skb_dequeue(&local->reject_queue))) {
 540                 rxrpc_see_skb(skb, rxrpc_skb_seen);
 541                 sp = rxrpc_skb(skb);
 542
 543                 switch (skb->mark) {
 544                 case RXRPC_SKB_MARK_REJECT_BUSY:
 545                         whdr.type = RXRPC_PACKET_TYPE_BUSY;
 546                         size = sizeof(whdr);
 547                         ioc = 1;
 548                         break;
 549                 case RXRPC_SKB_MARK_REJECT_ABORT:
 550                         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 551                         code = htonl(skb->priority);
 552                         size = sizeof(whdr) + sizeof(code);
 553                         ioc = 2;
 554                         break;
 555                 default:
 556                         rxrpc_free_skb(skb, rxrpc_skb_freed);
 557                         continue;
 558                 }
 559
 560                 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
 561                         msg.msg_namelen = srx.transport_len;
 562
 563                         whdr.epoch      = htonl(sp->hdr.epoch);
 564                         whdr.cid        = htonl(sp->hdr.cid);
 565                         whdr.callNumber = htonl(sp->hdr.callNumber);
 566                         whdr.serviceId  = htons(sp->hdr.serviceId);
 567                         whdr.flags      = sp->hdr.flags;
 568                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 569                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 570
 571                         ret = kernel_sendmsg(local->socket, &msg,
 572                                              iov, ioc, size);
 573                         if (ret < 0)
 574                                 trace_rxrpc_tx_fail(local->debug_id, 0, ret,
 575                                                     rxrpc_tx_point_reject);
 576                         else
 577                                 trace_rxrpc_tx_packet(local->debug_id, &whdr,
 578                                                       rxrpc_tx_point_reject);
 579                 }
 580
 581                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 582         }
 583
 584         _leave("");
 585 }
 586
 587 /*
 588  * Send a VERSION reply to a peer as a keepalive.
 589  */
 590 void rxrpc_send_keepalive(struct rxrpc_peer *peer)
 591 {
 592         struct rxrpc_wire_header whdr;
 593         struct msghdr msg;
 594         struct kvec iov[2];
 595         size_t len;
 596         int ret;
 597
 598         _enter("");
 599
 600         msg.msg_name    = &peer->srx.transport;
 601         msg.msg_namelen = peer->srx.transport_len;
 602         msg.msg_control = NULL;
 603         msg.msg_controllen = 0;
 604         msg.msg_flags   = 0;
 605
 606         whdr.epoch      = htonl(peer->local->rxnet->epoch);
 607         whdr.cid        = 0;
 608         whdr.callNumber = 0;
 609         whdr.seq        = 0;
 610         whdr.serial     = 0;
 611         whdr.type       = RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
 612         whdr.flags      = RXRPC_LAST_PACKET;
 613         whdr.userStatus = 0;
 614         whdr.securityIndex = 0;
 615         whdr._rsvd      = 0;
 616         whdr.serviceId  = 0;
 617
 618         iov[0].iov_base = &whdr;
 619         iov[0].iov_len  = sizeof(whdr);
 620         iov[1].iov_base = (char *)rxrpc_keepalive_string;
 621         iov[1].iov_len  = sizeof(rxrpc_keepalive_string);
 622
 623         len = iov[0].iov_len + iov[1].iov_len;
 624
 625         _proto("Tx VERSION (keepalive)");
 626
 627         ret = kernel_sendmsg(peer->local->socket, &msg, iov, 2, len);
 628         if (ret < 0)
 629                 trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
 630                                     rxrpc_tx_point_version_keepalive);
 631         else
 632                 trace_rxrpc_tx_packet(peer->debug_id, &whdr,
 633                                       rxrpc_tx_point_version_keepalive);
 634
 635         peer->last_tx_at = ktime_get_seconds();
 636         _leave("");
 637 }