git.rot13.org Git - linux/blob - 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  * Arrange for a keepalive ping a certain time after we last transmitted.  This
  39  * lets the far side know we're still interested in this call and helps keep
  40  * the route through any intervening firewall open.
  41  *
  42  * Receiving a response to the ping will prevent the ->expect_rx_by timer from
  43  * expiring.
  44  */
  45 static void rxrpc_set_keepalive(struct rxrpc_call *call)
  46 {
  47         unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
  48
  49         keepalive_at += now;
  50         WRITE_ONCE(call->keepalive_at, keepalive_at);
  51         rxrpc_reduce_call_timer(call, keepalive_at, now,
  52                                 rxrpc_timer_set_for_keepalive);
  53 }
  54
  55 /*
  56  * Fill out an ACK packet.
  57  */
  58 static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
  59                                  struct rxrpc_call *call,
  60                                  struct rxrpc_ack_buffer *pkt,
  61                                  rxrpc_seq_t *_hard_ack,
  62                                  rxrpc_seq_t *_top,
  63                                  u8 reason)
  64 {
  65         rxrpc_serial_t serial;
  66         rxrpc_seq_t hard_ack, top, seq;
  67         int ix;
  68         u32 mtu, jmax;
  69         u8 *ackp = pkt->acks;
  70
  71         /* Barrier against rxrpc_input_data(). */
  72         serial = call->ackr_serial;
  73         hard_ack = READ_ONCE(call->rx_hard_ack);
  74         top = smp_load_acquire(&call->rx_top);
  75         *_hard_ack = hard_ack;
  76         *_top = top;
  77
  78         pkt->ack.bufferSpace    = htons(8);
  79         pkt->ack.maxSkew        = htons(call->ackr_skew);
  80         pkt->ack.firstPacket    = htonl(hard_ack + 1);
  81         pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
  82         pkt->ack.serial         = htonl(serial);
  83         pkt->ack.reason         = reason;
  84         pkt->ack.nAcks          = top - hard_ack;
  85
  86         if (reason == RXRPC_ACK_PING)
  87                 pkt->whdr.flags |= RXRPC_REQUEST_ACK;
  88
  89         if (after(top, hard_ack)) {
  90                 seq = hard_ack + 1;
  91                 do {
  92                         ix = seq & RXRPC_RXTX_BUFF_MASK;
  93                         if (call->rxtx_buffer[ix])
  94                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
  95                         else
  96                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
  97                         seq++;
  98                 } while (before_eq(seq, top));
  99         }
 100
 101         mtu = conn->params.peer->if_mtu;
 102         mtu -= conn->params.peer->hdrsize;
 103         jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
 104         pkt->ackinfo.rxMTU      = htonl(rxrpc_rx_mtu);
 105         pkt->ackinfo.maxMTU     = htonl(mtu);
 106         pkt->ackinfo.rwind      = htonl(call->rx_winsize);
 107         pkt->ackinfo.jumbo_max  = htonl(jmax);
 108
 109         *ackp++ = 0;
 110         *ackp++ = 0;
 111         *ackp++ = 0;
 112         return top - hard_ack + 3;
 113 }
 114
 115 /*
 116  * Send an ACK call packet.
 117  */
 118 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
 119                           rxrpc_serial_t *_serial)
 120 {
 121         struct rxrpc_connection *conn = NULL;
 122         struct rxrpc_ack_buffer *pkt;
 123         struct msghdr msg;
 124         struct kvec iov[2];
 125         rxrpc_serial_t serial;
 126         rxrpc_seq_t hard_ack, top;
 127         size_t len, n;
 128         int ret;
 129         u8 reason;
 130
 131         spin_lock_bh(&call->lock);
 132         if (call->conn)
 133                 conn = rxrpc_get_connection_maybe(call->conn);
 134         spin_unlock_bh(&call->lock);
 135         if (!conn)
 136                 return -ECONNRESET;
 137
 138         pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 139         if (!pkt) {
 140                 rxrpc_put_connection(conn);
 141                 return -ENOMEM;
 142         }
 143
 144         msg.msg_name    = &call->peer->srx.transport;
 145         msg.msg_namelen = call->peer->srx.transport_len;
 146         msg.msg_control = NULL;
 147         msg.msg_controllen = 0;
 148         msg.msg_flags   = 0;
 149
 150         pkt->whdr.epoch         = htonl(conn->proto.epoch);
 151         pkt->whdr.cid           = htonl(call->cid);
 152         pkt->whdr.callNumber    = htonl(call->call_id);
 153         pkt->whdr.seq           = 0;
 154         pkt->whdr.type          = RXRPC_PACKET_TYPE_ACK;
 155         pkt->whdr.flags         = RXRPC_SLOW_START_OK | conn->out_clientflag;
 156         pkt->whdr.userStatus    = 0;
 157         pkt->whdr.securityIndex = call->security_ix;
 158         pkt->whdr._rsvd         = 0;
 159         pkt->whdr.serviceId     = htons(call->service_id);
 160
 161         spin_lock_bh(&call->lock);
 162         if (ping) {
 163                 reason = RXRPC_ACK_PING;
 164         } else {
 165                 reason = call->ackr_reason;
 166                 if (!call->ackr_reason) {
 167                         spin_unlock_bh(&call->lock);
 168                         ret = 0;
 169                         goto out;
 170                 }
 171                 call->ackr_reason = 0;
 172         }
 173         n = rxrpc_fill_out_ack(conn, call, pkt, &hard_ack, &top, reason);
 174
 175         spin_unlock_bh(&call->lock);
 176
 177         iov[0].iov_base = pkt;
 178         iov[0].iov_len  = sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
 179         iov[1].iov_base = &pkt->ackinfo;
 180         iov[1].iov_len  = sizeof(pkt->ackinfo);
 181         len = iov[0].iov_len + iov[1].iov_len;
 182
 183         serial = atomic_inc_return(&conn->serial);
 184         pkt->whdr.serial = htonl(serial);
 185         trace_rxrpc_tx_ack(call->debug_id, serial,
 186                            ntohl(pkt->ack.firstPacket),
 187                            ntohl(pkt->ack.serial),
 188                            pkt->ack.reason, pkt->ack.nAcks);
 189         if (_serial)
 190                 *_serial = serial;
 191
 192         if (ping) {
 193                 call->ping_serial = serial;
 194                 smp_wmb();
 195                 /* We need to stick a time in before we send the packet in case
 196                  * the reply gets back before kernel_sendmsg() completes - but
 197                  * asking UDP to send the packet can take a relatively long
 198                  * time.
 199                  */
 200                 call->ping_time = ktime_get_real();
 201                 set_bit(RXRPC_CALL_PINGING, &call->flags);
 202                 trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
 203         }
 204
 205         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 206         conn->params.peer->last_tx_at = ktime_get_seconds();
 207         if (ret < 0)
 208                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 209                                     rxrpc_tx_point_call_ack);
 210         else
 211                 trace_rxrpc_tx_packet(call->debug_id, &pkt->whdr,
 212                                       rxrpc_tx_point_call_ack);
 213
 214         if (call->state < RXRPC_CALL_COMPLETE) {
 215                 if (ret < 0) {
 216                         if (ping)
 217                                 clear_bit(RXRPC_CALL_PINGING, &call->flags);
 218                         rxrpc_propose_ACK(call, pkt->ack.reason,
 219                                           ntohs(pkt->ack.maxSkew),
 220                                           ntohl(pkt->ack.serial),
 221                                           true, true,
 222                                           rxrpc_propose_ack_retry_tx);
 223                 } else {
 224                         spin_lock_bh(&call->lock);
 225                         if (after(hard_ack, call->ackr_consumed))
 226                                 call->ackr_consumed = hard_ack;
 227                         if (after(top, call->ackr_seen))
 228                                 call->ackr_seen = top;
 229                         spin_unlock_bh(&call->lock);
 230                 }
 231
 232                 rxrpc_set_keepalive(call);
 233         }
 234
 235 out:
 236         rxrpc_put_connection(conn);
 237         kfree(pkt);
 238         return ret;
 239 }
 240
 241 /*
 242  * Send an ABORT call packet.
 243  */
 244 int rxrpc_send_abort_packet(struct rxrpc_call *call)
 245 {
 246         struct rxrpc_connection *conn = NULL;
 247         struct rxrpc_abort_buffer pkt;
 248         struct msghdr msg;
 249         struct kvec iov[1];
 250         rxrpc_serial_t serial;
 251         int ret;
 252
 253         /* Don't bother sending aborts for a client call once the server has
 254          * hard-ACK'd all of its request data.  After that point, we're not
 255          * going to stop the operation proceeding, and whilst we might limit
 256          * the reply, it's not worth it if we can send a new call on the same
 257          * channel instead, thereby closing off this call.
 258          */
 259         if (rxrpc_is_client_call(call) &&
 260             test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 261                 return 0;
 262
 263         spin_lock_bh(&call->lock);
 264         if (call->conn)
 265                 conn = rxrpc_get_connection_maybe(call->conn);
 266         spin_unlock_bh(&call->lock);
 267         if (!conn)
 268                 return -ECONNRESET;
 269
 270         msg.msg_name    = &call->peer->srx.transport;
 271         msg.msg_namelen = call->peer->srx.transport_len;
 272         msg.msg_control = NULL;
 273         msg.msg_controllen = 0;
 274         msg.msg_flags   = 0;
 275
 276         pkt.whdr.epoch          = htonl(conn->proto.epoch);
 277         pkt.whdr.cid            = htonl(call->cid);
 278         pkt.whdr.callNumber     = htonl(call->call_id);
 279         pkt.whdr.seq            = 0;
 280         pkt.whdr.type           = RXRPC_PACKET_TYPE_ABORT;
 281         pkt.whdr.flags          = conn->out_clientflag;
 282         pkt.whdr.userStatus     = 0;
 283         pkt.whdr.securityIndex  = call->security_ix;
 284         pkt.whdr._rsvd          = 0;
 285         pkt.whdr.serviceId      = htons(call->service_id);
 286         pkt.abort_code          = htonl(call->abort_code);
 287
 288         iov[0].iov_base = &pkt;
 289         iov[0].iov_len  = sizeof(pkt);
 290
 291         serial = atomic_inc_return(&conn->serial);
 292         pkt.whdr.serial = htonl(serial);
 293
 294         ret = kernel_sendmsg(conn->params.local->socket,
 295                              &msg, iov, 1, sizeof(pkt));
 296         conn->params.peer->last_tx_at = ktime_get_seconds();
 297         if (ret < 0)
 298                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 299                                     rxrpc_tx_point_call_abort);
 300         else
 301                 trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
 302                                       rxrpc_tx_point_call_abort);
 303
 304
 305         rxrpc_put_connection(conn);
 306         return ret;
 307 }
 308
 309 /*
 310  * send a packet through the transport endpoint
 311  */
 312 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 313                            bool retrans)
 314 {
 315         struct rxrpc_connection *conn = call->conn;
 316         struct rxrpc_wire_header whdr;
 317         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 318         struct msghdr msg;
 319         struct kvec iov[2];
 320         rxrpc_serial_t serial;
 321         size_t len;
 322         bool lost = false;
 323         int ret, opt;
 324
 325         _enter(",{%d}", skb->len);
 326
 327         /* Each transmission of a Tx packet needs a new serial number */
 328         serial = atomic_inc_return(&conn->serial);
 329
 330         whdr.epoch      = htonl(conn->proto.epoch);
 331         whdr.cid        = htonl(call->cid);
 332         whdr.callNumber = htonl(call->call_id);
 333         whdr.seq        = htonl(sp->hdr.seq);
 334         whdr.serial     = htonl(serial);
 335         whdr.type       = RXRPC_PACKET_TYPE_DATA;
 336         whdr.flags      = sp->hdr.flags;
 337         whdr.userStatus = 0;
 338         whdr.securityIndex = call->security_ix;
 339         whdr._rsvd      = htons(sp->hdr._rsvd);
 340         whdr.serviceId  = htons(call->service_id);
 341
 342         if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
 343             sp->hdr.seq == 1)
 344                 whdr.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
 345
 346         iov[0].iov_base = &whdr;
 347         iov[0].iov_len = sizeof(whdr);
 348         iov[1].iov_base = skb->head;
 349         iov[1].iov_len = skb->len;
 350         len = iov[0].iov_len + iov[1].iov_len;
 351
 352         msg.msg_name = &call->peer->srx.transport;
 353         msg.msg_namelen = call->peer->srx.transport_len;
 354         msg.msg_control = NULL;
 355         msg.msg_controllen = 0;
 356         msg.msg_flags = 0;
 357
 358         /* If our RTT cache needs working on, request an ACK.  Also request
 359          * ACKs if a DATA packet appears to have been lost.
 360          *
 361          * However, we mustn't request an ACK on the last reply packet of a
 362          * service call, lest OpenAFS incorrectly send us an ACK with some
 363          * soft-ACKs in it and then never follow up with a proper hard ACK.
 364          */
 365         if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) ||
 366              rxrpc_to_server(sp)
 367              ) &&
 368             (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||
 369              retrans ||
 370              call->cong_mode == RXRPC_CALL_SLOW_START ||
 371              (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
 372              ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
 373                           ktime_get_real())))
 374                 whdr.flags |= RXRPC_REQUEST_ACK;
 375
 376         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 377                 static int lose;
 378                 if ((lose++ & 7) == 7) {
 379                         ret = 0;
 380                         lost = true;
 381                 }
 382         }
 383
 384         trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
 385                             retrans, lost);
 386         if (lost)
 387                 goto done;
 388
 389         /* send the packet with the don't fragment bit set if we currently
 390          * think it's small enough */
 391         if (iov[1].iov_len >= call->peer->maxdata)
 392                 goto send_fragmentable;
 393
 394         down_read(&conn->params.local->defrag_sem);
 395
 396         sp->hdr.serial = serial;
 397         smp_wmb(); /* Set serial before timestamp */
 398         skb->tstamp = ktime_get_real();
 399
 400         /* send the packet by UDP
 401          * - returns -EMSGSIZE if UDP would have to fragment the packet
 402          *   to go out of the interface
 403          *   - in which case, we'll have processed the ICMP error
 404          *     message and update the peer record
 405          */
 406         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 407         conn->params.peer->last_tx_at = ktime_get_seconds();
 408
 409         up_read(&conn->params.local->defrag_sem);
 410         if (ret < 0)
 411                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 412                                     rxrpc_tx_point_call_data_nofrag);
 413         else
 414                 trace_rxrpc_tx_packet(call->debug_id, &whdr,
 415                                       rxrpc_tx_point_call_data_nofrag);
 416         if (ret == -EMSGSIZE)
 417                 goto send_fragmentable;
 418
 419 done:
 420         if (ret >= 0) {
 421                 if (whdr.flags & RXRPC_REQUEST_ACK) {
 422                         call->peer->rtt_last_req = skb->tstamp;
 423                         trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
 424                         if (call->peer->rtt_usage > 1) {
 425                                 unsigned long nowj = jiffies, ack_lost_at;
 426
 427                                 ack_lost_at = nsecs_to_jiffies(2 * call->peer->rtt);
 428                                 if (ack_lost_at < 1)
 429                                         ack_lost_at = 1;
 430
 431                                 ack_lost_at += nowj;
 432                                 WRITE_ONCE(call->ack_lost_at, ack_lost_at);
 433                                 rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
 434                                                         rxrpc_timer_set_for_lost_ack);
 435                         }
 436                 }
 437
 438                 if (sp->hdr.seq == 1 &&
 439                     !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
 440                                       &call->flags)) {
 441                         unsigned long nowj = jiffies, expect_rx_by;
 442
 443                         expect_rx_by = nowj + call->next_rx_timo;
 444                         WRITE_ONCE(call->expect_rx_by, expect_rx_by);
 445                         rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
 446                                                 rxrpc_timer_set_for_normal);
 447                 }
 448         }
 449
 450         rxrpc_set_keepalive(call);
 451
 452         _leave(" = %d [%u]", ret, call->peer->maxdata);
 453         return ret;
 454
 455 send_fragmentable:
 456         /* attempt to send this message with fragmentation enabled */
 457         _debug("send fragment");
 458
 459         down_write(&conn->params.local->defrag_sem);
 460
 461         sp->hdr.serial = serial;
 462         smp_wmb(); /* Set serial before timestamp */
 463         skb->tstamp = ktime_get_real();
 464
 465         switch (conn->params.local->srx.transport.family) {
 466         case AF_INET:
 467                 opt = IP_PMTUDISC_DONT;
 468                 ret = kernel_setsockopt(conn->params.local->socket,
 469                                         SOL_IP, IP_MTU_DISCOVER,
 470                                         (char *)&opt, sizeof(opt));
 471                 if (ret == 0) {
 472                         ret = kernel_sendmsg(conn->params.local->socket, &msg,
 473                                              iov, 2, len);
 474                         conn->params.peer->last_tx_at = ktime_get_seconds();
 475
 476                         opt = IP_PMTUDISC_DO;
 477                         kernel_setsockopt(conn->params.local->socket, SOL_IP,
 478                                           IP_MTU_DISCOVER,
 479                                           (char *)&opt, sizeof(opt));
 480                 }
 481                 break;
 482
 483 #ifdef CONFIG_AF_RXRPC_IPV6
 484         case AF_INET6:
 485                 opt = IPV6_PMTUDISC_DONT;
 486                 ret = kernel_setsockopt(conn->params.local->socket,
 487                                         SOL_IPV6, IPV6_MTU_DISCOVER,
 488                                         (char *)&opt, sizeof(opt));
 489                 if (ret == 0) {
 490                         ret = kernel_sendmsg(conn->params.local->socket, &msg,
 491                                              iov, 2, len);
 492                         conn->params.peer->last_tx_at = ktime_get_seconds();
 493
 494                         opt = IPV6_PMTUDISC_DO;
 495                         kernel_setsockopt(conn->params.local->socket,
 496                                           SOL_IPV6, IPV6_MTU_DISCOVER,
 497                                           (char *)&opt, sizeof(opt));
 498                 }
 499                 break;
 500 #endif
 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
 510         up_write(&conn->params.local->defrag_sem);
 511         goto done;
 512 }
 513
 514 /*
 515  * reject packets through the local endpoint
 516  */
 517 void rxrpc_reject_packets(struct rxrpc_local *local)
 518 {
 519         struct sockaddr_rxrpc srx;
 520         struct rxrpc_skb_priv *sp;
 521         struct rxrpc_wire_header whdr;
 522         struct sk_buff *skb;
 523         struct msghdr msg;
 524         struct kvec iov[2];
 525         size_t size;
 526         __be32 code;
 527         int ret, ioc;
 528
 529         _enter("%d", local->debug_id);
 530
 531         iov[0].iov_base = &whdr;
 532         iov[0].iov_len = sizeof(whdr);
 533         iov[1].iov_base = &code;
 534         iov[1].iov_len = sizeof(code);
 535
 536         msg.msg_name = &srx.transport;
 537         msg.msg_control = NULL;
 538         msg.msg_controllen = 0;
 539         msg.msg_flags = 0;
 540
 541         memset(&whdr, 0, sizeof(whdr));
 542
 543         while ((skb = skb_dequeue(&local->reject_queue))) {
 544                 rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 545                 sp = rxrpc_skb(skb);
 546
 547                 switch (skb->mark) {
 548                 case RXRPC_SKB_MARK_REJECT_BUSY:
 549                         whdr.type = RXRPC_PACKET_TYPE_BUSY;
 550                         size = sizeof(whdr);
 551                         ioc = 1;
 552                         break;
 553                 case RXRPC_SKB_MARK_REJECT_ABORT:
 554                         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 555                         code = htonl(skb->priority);
 556                         size = sizeof(whdr) + sizeof(code);
 557                         ioc = 2;
 558                         break;
 559                 default:
 560                         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 561                         continue;
 562                 }
 563
 564                 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
 565                         msg.msg_namelen = srx.transport_len;
 566
 567                         whdr.epoch      = htonl(sp->hdr.epoch);
 568                         whdr.cid        = htonl(sp->hdr.cid);
 569                         whdr.callNumber = htonl(sp->hdr.callNumber);
 570                         whdr.serviceId  = htons(sp->hdr.serviceId);
 571                         whdr.flags      = sp->hdr.flags;
 572                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 573                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 574
 575                         ret = kernel_sendmsg(local->socket, &msg,
 576                                              iov, ioc, size);
 577                         if (ret < 0)
 578                                 trace_rxrpc_tx_fail(local->debug_id, 0, ret,
 579                                                     rxrpc_tx_point_reject);
 580                         else
 581                                 trace_rxrpc_tx_packet(local->debug_id, &whdr,
 582                                                       rxrpc_tx_point_reject);
 583                 }
 584
 585                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 586         }
 587
 588         _leave("");
 589 }
 590
 591 /*
 592  * Send a VERSION reply to a peer as a keepalive.
 593  */
 594 void rxrpc_send_keepalive(struct rxrpc_peer *peer)
 595 {
 596         struct rxrpc_wire_header whdr;
 597         struct msghdr msg;
 598         struct kvec iov[2];
 599         size_t len;
 600         int ret;
 601
 602         _enter("");
 603
 604         msg.msg_name    = &peer->srx.transport;
 605         msg.msg_namelen = peer->srx.transport_len;
 606         msg.msg_control = NULL;
 607         msg.msg_controllen = 0;
 608         msg.msg_flags   = 0;
 609
 610         whdr.epoch      = htonl(peer->local->rxnet->epoch);
 611         whdr.cid        = 0;
 612         whdr.callNumber = 0;
 613         whdr.seq        = 0;
 614         whdr.serial     = 0;
 615         whdr.type       = RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
 616         whdr.flags      = RXRPC_LAST_PACKET;
 617         whdr.userStatus = 0;
 618         whdr.securityIndex = 0;
 619         whdr._rsvd      = 0;
 620         whdr.serviceId  = 0;
 621
 622         iov[0].iov_base = &whdr;
 623         iov[0].iov_len  = sizeof(whdr);
 624         iov[1].iov_base = (char *)rxrpc_keepalive_string;
 625         iov[1].iov_len  = sizeof(rxrpc_keepalive_string);
 626
 627         len = iov[0].iov_len + iov[1].iov_len;
 628
 629         _proto("Tx VERSION (keepalive)");
 630
 631         ret = kernel_sendmsg(peer->local->socket, &msg, iov, 2, len);
 632         if (ret < 0)
 633                 trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
 634                                     rxrpc_tx_point_version_keepalive);
 635         else
 636                 trace_rxrpc_tx_packet(peer->debug_id, &whdr,
 637                                       rxrpc_tx_point_version_keepalive);
 638
 639         peer->last_tx_at = ktime_get_seconds();
 640         _leave("");
 641 }