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 <net/udp.h>
  17 #include "ar-internal.h"
  18
  19 extern int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
  20
  21 static ssize_t do_udp_sendmsg(struct socket *sk, struct msghdr *msg, size_t len)
  22 {
  23 #if IS_ENABLED(CONFIG_AF_RXRPC_IPV6)
  24         struct sockaddr *sa = msg->msg_name;
  25
  26         if (sa->sa_family == AF_INET6)
  27                 return udpv6_sendmsg(sk->sk, msg, len);
  28 #endif
  29         return udp_sendmsg(sk->sk, msg, len);
  30 }
  31
  32 struct rxrpc_abort_buffer {
  33         struct rxrpc_wire_header whdr;
  34         __be32 abort_code;
  35 };
  36
  37 static const char rxrpc_keepalive_string[] = "";
  38
  39 /*
  40  * Increase Tx backoff on transmission failure and clear it on success.
  41  */
  42 static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret)
  43 {
  44         if (ret < 0) {
  45                 u16 tx_backoff = READ_ONCE(call->tx_backoff);
  46
  47                 if (tx_backoff < HZ)
  48                         WRITE_ONCE(call->tx_backoff, tx_backoff + 1);
  49         } else {
  50                 WRITE_ONCE(call->tx_backoff, 0);
  51         }
  52 }
  53
  54 /*
  55  * Arrange for a keepalive ping a certain time after we last transmitted.  This
  56  * lets the far side know we're still interested in this call and helps keep
  57  * the route through any intervening firewall open.
  58  *
  59  * Receiving a response to the ping will prevent the ->expect_rx_by timer from
  60  * expiring.
  61  */
  62 static void rxrpc_set_keepalive(struct rxrpc_call *call)
  63 {
  64         unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
  65
  66         keepalive_at += now;
  67         WRITE_ONCE(call->keepalive_at, keepalive_at);
  68         rxrpc_reduce_call_timer(call, keepalive_at, now,
  69                                 rxrpc_timer_set_for_keepalive);
  70 }
  71
  72 /*
  73  * Fill out an ACK packet.
  74  */
  75 static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
  76                                  struct rxrpc_call *call,
  77                                  struct rxrpc_txbuf *txb,
  78                                  rxrpc_seq_t *_hard_ack,
  79                                  rxrpc_seq_t *_top)
  80 {
  81         struct rxrpc_ackinfo ackinfo;
  82         unsigned int tmp;
  83         rxrpc_seq_t hard_ack, top, seq;
  84         int ix;
  85         u32 mtu, jmax;
  86         u8 *ackp = txb->acks;
  87
  88         tmp = atomic_xchg(&call->ackr_nr_unacked, 0);
  89         tmp |= atomic_xchg(&call->ackr_nr_consumed, 0);
  90         if (!tmp && (txb->ack.reason == RXRPC_ACK_DELAY ||
  91                      txb->ack.reason == RXRPC_ACK_IDLE)) {
  92                 rxrpc_inc_stat(call->rxnet, stat_tx_ack_skip);
  93                 return 0;
  94         }
  95
  96         rxrpc_inc_stat(call->rxnet, stat_tx_ack_fill);
  97
  98         /* Barrier against rxrpc_input_data(). */
  99         hard_ack = READ_ONCE(call->rx_hard_ack);
 100         top = smp_load_acquire(&call->rx_top);
 101         *_hard_ack = hard_ack;
 102         *_top = top;
 103
 104         txb->ack.firstPacket    = htonl(hard_ack + 1);
 105         txb->ack.previousPacket = htonl(call->ackr_highest_seq);
 106         txb->ack.nAcks          = top - hard_ack;
 107
 108         if (txb->ack.nAcks) {
 109                 seq = hard_ack + 1;
 110                 do {
 111                         ix = seq & RXRPC_RXTX_BUFF_MASK;
 112                         if (call->rxtx_buffer[ix])
 113                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
 114                         else
 115                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
 116                         seq++;
 117                 } while (before_eq(seq, top));
 118         }
 119
 120         mtu = conn->params.peer->if_mtu;
 121         mtu -= conn->params.peer->hdrsize;
 122         jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
 123         ackinfo.rxMTU           = htonl(rxrpc_rx_mtu);
 124         ackinfo.maxMTU          = htonl(mtu);
 125         ackinfo.rwind           = htonl(call->rx_winsize);
 126         ackinfo.jumbo_max       = htonl(jmax);
 127
 128         *ackp++ = 0;
 129         *ackp++ = 0;
 130         *ackp++ = 0;
 131         memcpy(ackp, &ackinfo, sizeof(ackinfo));
 132         return top - hard_ack + 3 + sizeof(ackinfo);
 133 }
 134
 135 /*
 136  * Record the beginning of an RTT probe.
 137  */
 138 static int rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial,
 139                                  enum rxrpc_rtt_tx_trace why)
 140 {
 141         unsigned long avail = call->rtt_avail;
 142         int rtt_slot = 9;
 143
 144         if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK))
 145                 goto no_slot;
 146
 147         rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK);
 148         if (!test_and_clear_bit(rtt_slot, &call->rtt_avail))
 149                 goto no_slot;
 150
 151         call->rtt_serial[rtt_slot] = serial;
 152         call->rtt_sent_at[rtt_slot] = ktime_get_real();
 153         smp_wmb(); /* Write data before avail bit */
 154         set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 155
 156         trace_rxrpc_rtt_tx(call, why, rtt_slot, serial);
 157         return rtt_slot;
 158
 159 no_slot:
 160         trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial);
 161         return -1;
 162 }
 163
 164 /*
 165  * Cancel an RTT probe.
 166  */
 167 static void rxrpc_cancel_rtt_probe(struct rxrpc_call *call,
 168                                    rxrpc_serial_t serial, int rtt_slot)
 169 {
 170         if (rtt_slot != -1) {
 171                 clear_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 172                 smp_wmb(); /* Clear pending bit before setting slot */
 173                 set_bit(rtt_slot, &call->rtt_avail);
 174                 trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_cancel, rtt_slot, serial);
 175         }
 176 }
 177
 178 /*
 179  * Send an ACK call packet.
 180  */
 181 static int rxrpc_send_ack_packet(struct rxrpc_local *local, struct rxrpc_txbuf *txb)
 182 {
 183         struct rxrpc_connection *conn;
 184         struct rxrpc_ack_buffer *pkt;
 185         struct rxrpc_call *call = txb->call;
 186         struct msghdr msg;
 187         struct kvec iov[1];
 188         rxrpc_serial_t serial;
 189         rxrpc_seq_t hard_ack, top;
 190         size_t len, n;
 191         int ret, rtt_slot = -1;
 192
 193         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
 194                 return -ECONNRESET;
 195
 196         conn = call->conn;
 197
 198         msg.msg_name    = &call->peer->srx.transport;
 199         msg.msg_namelen = call->peer->srx.transport_len;
 200         msg.msg_control = NULL;
 201         msg.msg_controllen = 0;
 202         msg.msg_flags   = 0;
 203
 204         if (txb->ack.reason == RXRPC_ACK_PING)
 205                 txb->wire.flags |= RXRPC_REQUEST_ACK;
 206
 207         spin_lock_bh(&call->lock);
 208         n = rxrpc_fill_out_ack(conn, call, txb, &hard_ack, &top);
 209         spin_unlock_bh(&call->lock);
 210         if (n == 0) {
 211                 kfree(pkt);
 212                 return 0;
 213         }
 214
 215         iov[0].iov_base = &txb->wire;
 216         iov[0].iov_len  = sizeof(txb->wire) + sizeof(txb->ack) + n;
 217         len = iov[0].iov_len;
 218
 219         serial = atomic_inc_return(&conn->serial);
 220         txb->wire.serial = htonl(serial);
 221         trace_rxrpc_tx_ack(call->debug_id, serial,
 222                            ntohl(txb->ack.firstPacket),
 223                            ntohl(txb->ack.serial), txb->ack.reason, txb->ack.nAcks);
 224         if (txb->ack_why == rxrpc_propose_ack_ping_for_lost_ack)
 225                 call->acks_lost_ping = serial;
 226
 227         if (txb->ack.reason == RXRPC_ACK_PING)
 228                 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_ping);
 229
 230         rxrpc_inc_stat(call->rxnet, stat_tx_ack_send);
 231
 232         iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
 233         ret = do_udp_sendmsg(conn->params.local->socket, &msg, len);
 234         call->peer->last_tx_at = ktime_get_seconds();
 235         if (ret < 0)
 236                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 237                                     rxrpc_tx_point_call_ack);
 238         else
 239                 trace_rxrpc_tx_packet(call->debug_id, &txb->wire,
 240                                       rxrpc_tx_point_call_ack);
 241         rxrpc_tx_backoff(call, ret);
 242
 243         if (call->state < RXRPC_CALL_COMPLETE) {
 244                 if (ret < 0)
 245                         rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
 246                 rxrpc_set_keepalive(call);
 247         }
 248
 249         kfree(pkt);
 250         return ret;
 251 }
 252
 253 /*
 254  * ACK transmitter for a local endpoint.  The UDP socket locks around each
 255  * transmission, so we can only transmit one packet at a time, ACK, DATA or
 256  * otherwise.
 257  */
 258 void rxrpc_transmit_ack_packets(struct rxrpc_local *local)
 259 {
 260         LIST_HEAD(queue);
 261         int ret;
 262
 263         trace_rxrpc_local(local->debug_id, rxrpc_local_tx_ack,
 264                           refcount_read(&local->ref), NULL);
 265
 266         if (list_empty(&local->ack_tx_queue))
 267                 return;
 268
 269         spin_lock_bh(&local->ack_tx_lock);
 270         list_splice_tail_init(&local->ack_tx_queue, &queue);
 271         spin_unlock_bh(&local->ack_tx_lock);
 272
 273         while (!list_empty(&queue)) {
 274                 struct rxrpc_txbuf *txb =
 275                         list_entry(queue.next, struct rxrpc_txbuf, tx_link);
 276
 277                 ret = rxrpc_send_ack_packet(local, txb);
 278                 if (ret < 0 && ret != -ECONNRESET) {
 279                         spin_lock_bh(&local->ack_tx_lock);
 280                         list_splice_init(&queue, &local->ack_tx_queue);
 281                         spin_unlock_bh(&local->ack_tx_lock);
 282                         break;
 283                 }
 284
 285                 list_del_init(&txb->tx_link);
 286                 rxrpc_put_call(txb->call, rxrpc_call_put);
 287                 rxrpc_put_txbuf(txb, rxrpc_txbuf_put_ack_tx);
 288         }
 289 }
 290
 291 /*
 292  * Send an ABORT call packet.
 293  */
 294 int rxrpc_send_abort_packet(struct rxrpc_call *call)
 295 {
 296         struct rxrpc_connection *conn;
 297         struct rxrpc_abort_buffer pkt;
 298         struct msghdr msg;
 299         struct kvec iov[1];
 300         rxrpc_serial_t serial;
 301         int ret;
 302
 303         /* Don't bother sending aborts for a client call once the server has
 304          * hard-ACK'd all of its request data.  After that point, we're not
 305          * going to stop the operation proceeding, and whilst we might limit
 306          * the reply, it's not worth it if we can send a new call on the same
 307          * channel instead, thereby closing off this call.
 308          */
 309         if (rxrpc_is_client_call(call) &&
 310             test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 311                 return 0;
 312
 313         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
 314                 return -ECONNRESET;
 315
 316         conn = call->conn;
 317
 318         msg.msg_name    = &call->peer->srx.transport;
 319         msg.msg_namelen = call->peer->srx.transport_len;
 320         msg.msg_control = NULL;
 321         msg.msg_controllen = 0;
 322         msg.msg_flags   = 0;
 323
 324         pkt.whdr.epoch          = htonl(conn->proto.epoch);
 325         pkt.whdr.cid            = htonl(call->cid);
 326         pkt.whdr.callNumber     = htonl(call->call_id);
 327         pkt.whdr.seq            = 0;
 328         pkt.whdr.type           = RXRPC_PACKET_TYPE_ABORT;
 329         pkt.whdr.flags          = conn->out_clientflag;
 330         pkt.whdr.userStatus     = 0;
 331         pkt.whdr.securityIndex  = call->security_ix;
 332         pkt.whdr._rsvd          = 0;
 333         pkt.whdr.serviceId      = htons(call->service_id);
 334         pkt.abort_code          = htonl(call->abort_code);
 335
 336         iov[0].iov_base = &pkt;
 337         iov[0].iov_len  = sizeof(pkt);
 338
 339         serial = atomic_inc_return(&conn->serial);
 340         pkt.whdr.serial = htonl(serial);
 341
 342         iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, sizeof(pkt));
 343         ret = do_udp_sendmsg(conn->params.local->socket, &msg, sizeof(pkt));
 344         conn->params.peer->last_tx_at = ktime_get_seconds();
 345         if (ret < 0)
 346                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 347                                     rxrpc_tx_point_call_abort);
 348         else
 349                 trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr,
 350                                       rxrpc_tx_point_call_abort);
 351         rxrpc_tx_backoff(call, ret);
 352         return ret;
 353 }
 354
 355 /*
 356  * send a packet through the transport endpoint
 357  */
 358 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 359                            bool retrans)
 360 {
 361         enum rxrpc_req_ack_trace why;
 362         struct rxrpc_connection *conn = call->conn;
 363         struct rxrpc_wire_header whdr;
 364         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 365         struct msghdr msg;
 366         struct kvec iov[2];
 367         rxrpc_serial_t serial;
 368         size_t len;
 369         int ret, rtt_slot = -1;
 370
 371         _enter(",{%d}", skb->len);
 372
 373         if (hlist_unhashed(&call->error_link)) {
 374                 spin_lock_bh(&call->peer->lock);
 375                 hlist_add_head_rcu(&call->error_link, &call->peer->error_targets);
 376                 spin_unlock_bh(&call->peer->lock);
 377         }
 378
 379         /* Each transmission of a Tx packet needs a new serial number */
 380         serial = atomic_inc_return(&conn->serial);
 381
 382         whdr.epoch      = htonl(conn->proto.epoch);
 383         whdr.cid        = htonl(call->cid);
 384         whdr.callNumber = htonl(call->call_id);
 385         whdr.seq        = htonl(sp->hdr.seq);
 386         whdr.serial     = htonl(serial);
 387         whdr.type       = RXRPC_PACKET_TYPE_DATA;
 388         whdr.flags      = sp->hdr.flags;
 389         whdr.userStatus = 0;
 390         whdr.securityIndex = call->security_ix;
 391         whdr._rsvd      = htons(sp->hdr._rsvd);
 392         whdr.serviceId  = htons(call->service_id);
 393
 394         if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
 395             sp->hdr.seq == 1)
 396                 whdr.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
 397
 398         iov[0].iov_base = &whdr;
 399         iov[0].iov_len = sizeof(whdr);
 400         iov[1].iov_base = skb->head;
 401         iov[1].iov_len = skb->len;
 402         len = iov[0].iov_len + iov[1].iov_len;
 403         iov_iter_kvec(&msg.msg_iter, WRITE, iov, 2, len);
 404
 405         msg.msg_name = &call->peer->srx.transport;
 406         msg.msg_namelen = call->peer->srx.transport_len;
 407         msg.msg_control = NULL;
 408         msg.msg_controllen = 0;
 409         msg.msg_flags = 0;
 410
 411         /* If our RTT cache needs working on, request an ACK.  Also request
 412          * ACKs if a DATA packet appears to have been lost.
 413          *
 414          * However, we mustn't request an ACK on the last reply packet of a
 415          * service call, lest OpenAFS incorrectly send us an ACK with some
 416          * soft-ACKs in it and then never follow up with a proper hard ACK.
 417          */
 418         if (whdr.flags & RXRPC_REQUEST_ACK)
 419                 why = rxrpc_reqack_already_on;
 420         else if ((whdr.flags & RXRPC_LAST_PACKET) && rxrpc_to_client(sp))
 421                 why = rxrpc_reqack_no_srv_last;
 422         else if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events))
 423                 why = rxrpc_reqack_ack_lost;
 424         else if (retrans)
 425                 why = rxrpc_reqack_retrans;
 426         else if (call->cong_mode == RXRPC_CALL_SLOW_START && call->cong_cwnd <= 2)
 427                 why = rxrpc_reqack_slow_start;
 428         else if (call->tx_winsize <= 2)
 429                 why = rxrpc_reqack_small_txwin;
 430         else if (call->peer->rtt_count < 3 && sp->hdr.seq & 1)
 431                 why = rxrpc_reqack_more_rtt;
 432         else if (ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), ktime_get_real()))
 433                 why = rxrpc_reqack_old_rtt;
 434         else
 435                 goto dont_set_request_ack;
 436
 437         rxrpc_inc_stat(call->rxnet, stat_why_req_ack[why]);
 438         trace_rxrpc_req_ack(call->debug_id, sp->hdr.seq, why);
 439         if (why != rxrpc_reqack_no_srv_last)
 440                 whdr.flags |= RXRPC_REQUEST_ACK;
 441 dont_set_request_ack:
 442
 443         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 444                 static int lose;
 445                 if ((lose++ & 7) == 7) {
 446                         ret = 0;
 447                         trace_rxrpc_tx_data(call, sp->hdr.seq, serial,
 448                                             whdr.flags, retrans, true);
 449                         goto done;
 450                 }
 451         }
 452
 453         trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, retrans,
 454                             false);
 455
 456         /* send the packet with the don't fragment bit set if we currently
 457          * think it's small enough */
 458         if (iov[1].iov_len >= call->peer->maxdata)
 459                 goto send_fragmentable;
 460
 461         down_read(&conn->params.local->defrag_sem);
 462
 463         sp->hdr.serial = serial;
 464         smp_wmb(); /* Set serial before timestamp */
 465         skb->tstamp = ktime_get_real();
 466         if (whdr.flags & RXRPC_REQUEST_ACK)
 467                 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
 468
 469         /* send the packet by UDP
 470          * - returns -EMSGSIZE if UDP would have to fragment the packet
 471          *   to go out of the interface
 472          *   - in which case, we'll have processed the ICMP error
 473          *     message and update the peer record
 474          */
 475         rxrpc_inc_stat(call->rxnet, stat_tx_data_send);
 476         ret = do_udp_sendmsg(conn->params.local->socket, &msg, len);
 477         conn->params.peer->last_tx_at = ktime_get_seconds();
 478
 479         up_read(&conn->params.local->defrag_sem);
 480         if (ret < 0) {
 481                 rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
 482                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 483                                     rxrpc_tx_point_call_data_nofrag);
 484         } else {
 485                 trace_rxrpc_tx_packet(call->debug_id, &whdr,
 486                                       rxrpc_tx_point_call_data_nofrag);
 487         }
 488
 489         rxrpc_tx_backoff(call, ret);
 490         if (ret == -EMSGSIZE)
 491                 goto send_fragmentable;
 492
 493 done:
 494         if (ret >= 0) {
 495                 if (whdr.flags & RXRPC_REQUEST_ACK) {
 496                         call->peer->rtt_last_req = skb->tstamp;
 497                         if (call->peer->rtt_count > 1) {
 498                                 unsigned long nowj = jiffies, ack_lost_at;
 499
 500                                 ack_lost_at = rxrpc_get_rto_backoff(call->peer, false);
 501                                 ack_lost_at += nowj;
 502                                 WRITE_ONCE(call->ack_lost_at, ack_lost_at);
 503                                 rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
 504                                                         rxrpc_timer_set_for_lost_ack);
 505                         }
 506                 }
 507
 508                 if (sp->hdr.seq == 1 &&
 509                     !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER,
 510                                       &call->flags)) {
 511                         unsigned long nowj = jiffies, expect_rx_by;
 512
 513                         expect_rx_by = nowj + call->next_rx_timo;
 514                         WRITE_ONCE(call->expect_rx_by, expect_rx_by);
 515                         rxrpc_reduce_call_timer(call, expect_rx_by, nowj,
 516                                                 rxrpc_timer_set_for_normal);
 517                 }
 518
 519                 rxrpc_set_keepalive(call);
 520         } else {
 521                 /* Cancel the call if the initial transmission fails,
 522                  * particularly if that's due to network routing issues that
 523                  * aren't going away anytime soon.  The layer above can arrange
 524                  * the retransmission.
 525                  */
 526                 if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags))
 527                         rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
 528                                                   RX_USER_ABORT, ret);
 529         }
 530
 531         _leave(" = %d [%u]", ret, call->peer->maxdata);
 532         return ret;
 533
 534 send_fragmentable:
 535         /* attempt to send this message with fragmentation enabled */
 536         _debug("send fragment");
 537
 538         down_write(&conn->params.local->defrag_sem);
 539
 540         sp->hdr.serial = serial;
 541         smp_wmb(); /* Set serial before timestamp */
 542         skb->tstamp = ktime_get_real();
 543         if (whdr.flags & RXRPC_REQUEST_ACK)
 544                 rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data);
 545
 546         switch (conn->params.local->srx.transport.family) {
 547         case AF_INET6:
 548         case AF_INET:
 549                 ip_sock_set_mtu_discover(conn->params.local->socket->sk,
 550                                 IP_PMTUDISC_DONT);
 551                 rxrpc_inc_stat(call->rxnet, stat_tx_data_send_frag);
 552                 ret = do_udp_sendmsg(conn->params.local->socket, &msg, len);
 553                 conn->params.peer->last_tx_at = ktime_get_seconds();
 554
 555                 ip_sock_set_mtu_discover(conn->params.local->socket->sk,
 556                                 IP_PMTUDISC_DO);
 557                 break;
 558
 559         default:
 560                 BUG();
 561         }
 562
 563         if (ret < 0) {
 564                 rxrpc_cancel_rtt_probe(call, serial, rtt_slot);
 565                 trace_rxrpc_tx_fail(call->debug_id, serial, ret,
 566                                     rxrpc_tx_point_call_data_frag);
 567         } else {
 568                 trace_rxrpc_tx_packet(call->debug_id, &whdr,
 569                                       rxrpc_tx_point_call_data_frag);
 570         }
 571         rxrpc_tx_backoff(call, ret);
 572
 573         up_write(&conn->params.local->defrag_sem);
 574         goto done;
 575 }
 576
 577 /*
 578  * reject packets through the local endpoint
 579  */
 580 void rxrpc_reject_packets(struct rxrpc_local *local)
 581 {
 582         struct sockaddr_rxrpc srx;
 583         struct rxrpc_skb_priv *sp;
 584         struct rxrpc_wire_header whdr;
 585         struct sk_buff *skb;
 586         struct msghdr msg;
 587         struct kvec iov[2];
 588         size_t size;
 589         __be32 code;
 590         int ret, ioc;
 591
 592         _enter("%d", local->debug_id);
 593
 594         iov[0].iov_base = &whdr;
 595         iov[0].iov_len = sizeof(whdr);
 596         iov[1].iov_base = &code;
 597         iov[1].iov_len = sizeof(code);
 598
 599         msg.msg_name = &srx.transport;
 600         msg.msg_control = NULL;
 601         msg.msg_controllen = 0;
 602         msg.msg_flags = 0;
 603
 604         memset(&whdr, 0, sizeof(whdr));
 605
 606         while ((skb = skb_dequeue(&local->reject_queue))) {
 607                 rxrpc_see_skb(skb, rxrpc_skb_seen);
 608                 sp = rxrpc_skb(skb);
 609
 610                 switch (skb->mark) {
 611                 case RXRPC_SKB_MARK_REJECT_BUSY:
 612                         whdr.type = RXRPC_PACKET_TYPE_BUSY;
 613                         size = sizeof(whdr);
 614                         ioc = 1;
 615                         break;
 616                 case RXRPC_SKB_MARK_REJECT_ABORT:
 617                         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 618                         code = htonl(skb->priority);
 619                         size = sizeof(whdr) + sizeof(code);
 620                         ioc = 2;
 621                         break;
 622                 default:
 623                         rxrpc_free_skb(skb, rxrpc_skb_freed);
 624                         continue;
 625                 }
 626
 627                 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
 628                         msg.msg_namelen = srx.transport_len;
 629
 630                         whdr.epoch      = htonl(sp->hdr.epoch);
 631                         whdr.cid        = htonl(sp->hdr.cid);
 632                         whdr.callNumber = htonl(sp->hdr.callNumber);
 633                         whdr.serviceId  = htons(sp->hdr.serviceId);
 634                         whdr.flags      = sp->hdr.flags;
 635                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 636                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 637
 638                         iov_iter_kvec(&msg.msg_iter, WRITE, iov, ioc, size);
 639                         ret = do_udp_sendmsg(local->socket, &msg, size);
 640                         if (ret < 0)
 641                                 trace_rxrpc_tx_fail(local->debug_id, 0, ret,
 642                                                     rxrpc_tx_point_reject);
 643                         else
 644                                 trace_rxrpc_tx_packet(local->debug_id, &whdr,
 645                                                       rxrpc_tx_point_reject);
 646                 }
 647
 648                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 649         }
 650
 651         _leave("");
 652 }
 653
 654 /*
 655  * Send a VERSION reply to a peer as a keepalive.
 656  */
 657 void rxrpc_send_keepalive(struct rxrpc_peer *peer)
 658 {
 659         struct rxrpc_wire_header whdr;
 660         struct msghdr msg;
 661         struct kvec iov[2];
 662         size_t len;
 663         int ret;
 664
 665         _enter("");
 666
 667         msg.msg_name    = &peer->srx.transport;
 668         msg.msg_namelen = peer->srx.transport_len;
 669         msg.msg_control = NULL;
 670         msg.msg_controllen = 0;
 671         msg.msg_flags   = 0;
 672
 673         whdr.epoch      = htonl(peer->local->rxnet->epoch);
 674         whdr.cid        = 0;
 675         whdr.callNumber = 0;
 676         whdr.seq        = 0;
 677         whdr.serial     = 0;
 678         whdr.type       = RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */
 679         whdr.flags      = RXRPC_LAST_PACKET;
 680         whdr.userStatus = 0;
 681         whdr.securityIndex = 0;
 682         whdr._rsvd      = 0;
 683         whdr.serviceId  = 0;
 684
 685         iov[0].iov_base = &whdr;
 686         iov[0].iov_len  = sizeof(whdr);
 687         iov[1].iov_base = (char *)rxrpc_keepalive_string;
 688         iov[1].iov_len  = sizeof(rxrpc_keepalive_string);
 689
 690         len = iov[0].iov_len + iov[1].iov_len;
 691
 692         _proto("Tx VERSION (keepalive)");
 693
 694         iov_iter_kvec(&msg.msg_iter, WRITE, iov, 2, len);
 695         ret = do_udp_sendmsg(peer->local->socket, &msg, len);
 696         if (ret < 0)
 697                 trace_rxrpc_tx_fail(peer->debug_id, 0, ret,
 698                                     rxrpc_tx_point_version_keepalive);
 699         else
 700                 trace_rxrpc_tx_packet(peer->debug_id, &whdr,
 701                                       rxrpc_tx_point_version_keepalive);
 702
 703         peer->last_tx_at = ktime_get_seconds();
 704         _leave("");
 705 }