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 /*
  36  * Arrange for a keepalive ping a certain time after we last transmitted.  This
  37  * lets the far side know we're still interested in this call and helps keep
  38  * the route through any intervening firewall open.
  39  *
  40  * Receiving a response to the ping will prevent the ->expect_rx_by timer from
  41  * expiring.
  42  */
  43 static void rxrpc_set_keepalive(struct rxrpc_call *call)
  44 {
  45         unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
  46
  47         keepalive_at += now;
  48         WRITE_ONCE(call->keepalive_at, keepalive_at);
  49         rxrpc_reduce_call_timer(call, keepalive_at, now,
  50                                 rxrpc_timer_set_for_keepalive);
  51 }
  52
  53 /*
  54  * Fill out an ACK packet.
  55  */
  56 static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
  57                                  struct rxrpc_call *call,
  58                                  struct rxrpc_ack_buffer *pkt,
  59                                  rxrpc_seq_t *_hard_ack,
  60                                  rxrpc_seq_t *_top,
  61                                  u8 reason)
  62 {
  63         rxrpc_serial_t serial;
  64         rxrpc_seq_t hard_ack, top, seq;
  65         int ix;
  66         u32 mtu, jmax;
  67         u8 *ackp = pkt->acks;
  68
  69         /* Barrier against rxrpc_input_data(). */
  70         serial = call->ackr_serial;
  71         hard_ack = READ_ONCE(call->rx_hard_ack);
  72         top = smp_load_acquire(&call->rx_top);
  73         *_hard_ack = hard_ack;
  74         *_top = top;
  75
  76         pkt->ack.bufferSpace    = htons(8);
  77         pkt->ack.maxSkew        = htons(call->ackr_skew);
  78         pkt->ack.firstPacket    = htonl(hard_ack + 1);
  79         pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
  80         pkt->ack.serial         = htonl(serial);
  81         pkt->ack.reason         = reason;
  82         pkt->ack.nAcks          = top - hard_ack;
  83
  84         if (reason == RXRPC_ACK_PING)
  85                 pkt->whdr.flags |= RXRPC_REQUEST_ACK;
  86
  87         if (after(top, hard_ack)) {
  88                 seq = hard_ack + 1;
  89                 do {
  90                         ix = seq & RXRPC_RXTX_BUFF_MASK;
  91                         if (call->rxtx_buffer[ix])
  92                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
  93                         else
  94                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
  95                         seq++;
  96                 } while (before_eq(seq, top));
  97         }
  98
  99         mtu = conn->params.peer->if_mtu;
 100         mtu -= conn->params.peer->hdrsize;
 101         jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
 102         pkt->ackinfo.rxMTU      = htonl(rxrpc_rx_mtu);
 103         pkt->ackinfo.maxMTU     = htonl(mtu);
 104         pkt->ackinfo.rwind      = htonl(call->rx_winsize);
 105         pkt->ackinfo.jumbo_max  = htonl(jmax);
 106
 107         *ackp++ = 0;
 108         *ackp++ = 0;
 109         *ackp++ = 0;
 110         return top - hard_ack + 3;
 111 }
 112
 113 /*
 114  * Send an ACK call packet.
 115  */
 116 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
 117                           rxrpc_serial_t *_serial)
 118 {
 119         struct rxrpc_connection *conn = NULL;
 120         struct rxrpc_ack_buffer *pkt;
 121         struct msghdr msg;
 122         struct kvec iov[2];
 123         rxrpc_serial_t serial;
 124         rxrpc_seq_t hard_ack, top;
 125         size_t len, n;
 126         int ret;
 127         u8 reason;
 128
 129         spin_lock_bh(&call->lock);
 130         if (call->conn)
 131                 conn = rxrpc_get_connection_maybe(call->conn);
 132         spin_unlock_bh(&call->lock);
 133         if (!conn)
 134                 return -ECONNRESET;
 135
 136         pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 137         if (!pkt) {
 138                 rxrpc_put_connection(conn);
 139                 return -ENOMEM;
 140         }
 141
 142         msg.msg_name    = &call->peer->srx.transport;
 143         msg.msg_namelen = call->peer->srx.transport_len;
 144         msg.msg_control = NULL;
 145         msg.msg_controllen = 0;
 146         msg.msg_flags   = 0;
 147
 148         pkt->whdr.epoch         = htonl(conn->proto.epoch);
 149         pkt->whdr.cid           = htonl(call->cid);
 150         pkt->whdr.callNumber    = htonl(call->call_id);
 151         pkt->whdr.seq           = 0;
 152         pkt->whdr.type          = RXRPC_PACKET_TYPE_ACK;
 153         pkt->whdr.flags         = RXRPC_SLOW_START_OK | conn->out_clientflag;
 154         pkt->whdr.userStatus    = 0;
 155         pkt->whdr.securityIndex = call->security_ix;
 156         pkt->whdr._rsvd         = 0;
 157         pkt->whdr.serviceId     = htons(call->service_id);
 158
 159         spin_lock_bh(&call->lock);
 160         if (ping) {
 161                 reason = RXRPC_ACK_PING;
 162         } else {
 163                 reason = call->ackr_reason;
 164                 if (!call->ackr_reason) {
 165                         spin_unlock_bh(&call->lock);
 166                         ret = 0;
 167                         goto out;
 168                 }
 169                 call->ackr_reason = 0;
 170         }
 171         n = rxrpc_fill_out_ack(conn, call, pkt, &hard_ack, &top, reason);
 172
 173         spin_unlock_bh(&call->lock);
 174
 175         iov[0].iov_base = pkt;
 176         iov[0].iov_len  = sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
 177         iov[1].iov_base = &pkt->ackinfo;
 178         iov[1].iov_len  = sizeof(pkt->ackinfo);
 179         len = iov[0].iov_len + iov[1].iov_len;
 180
 181         serial = atomic_inc_return(&conn->serial);
 182         pkt->whdr.serial = htonl(serial);
 183         trace_rxrpc_tx_ack(call, serial,
 184                            ntohl(pkt->ack.firstPacket),
 185                            ntohl(pkt->ack.serial),
 186                            pkt->ack.reason, pkt->ack.nAcks);
 187         if (_serial)
 188                 *_serial = serial;
 189
 190         if (ping) {
 191                 call->ping_serial = serial;
 192                 smp_wmb();
 193                 /* We need to stick a time in before we send the packet in case
 194                  * the reply gets back before kernel_sendmsg() completes - but
 195                  * asking UDP to send the packet can take a relatively long
 196                  * time, so we update the time after, on the assumption that
 197                  * the packet transmission is more likely to happen towards the
 198                  * end of the kernel_sendmsg() call.
 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         if (ping)
 207                 call->ping_time = ktime_get_real();
 208
 209         if (call->state < RXRPC_CALL_COMPLETE) {
 210                 if (ret < 0) {
 211                         if (ping)
 212                                 clear_bit(RXRPC_CALL_PINGING, &call->flags);
 213                         rxrpc_propose_ACK(call, pkt->ack.reason,
 214                                           ntohs(pkt->ack.maxSkew),
 215                                           ntohl(pkt->ack.serial),
 216                                           true, true,
 217                                           rxrpc_propose_ack_retry_tx);
 218                 } else {
 219                         spin_lock_bh(&call->lock);
 220                         if (after(hard_ack, call->ackr_consumed))
 221                                 call->ackr_consumed = hard_ack;
 222                         if (after(top, call->ackr_seen))
 223                                 call->ackr_seen = top;
 224                         spin_unlock_bh(&call->lock);
 225                 }
 226
 227                 rxrpc_set_keepalive(call);
 228         }
 229
 230 out:
 231         rxrpc_put_connection(conn);
 232         kfree(pkt);
 233         return ret;
 234 }
 235
 236 /*
 237  * Send an ABORT call packet.
 238  */
 239 int rxrpc_send_abort_packet(struct rxrpc_call *call)
 240 {
 241         struct rxrpc_connection *conn = NULL;
 242         struct rxrpc_abort_buffer pkt;
 243         struct msghdr msg;
 244         struct kvec iov[1];
 245         rxrpc_serial_t serial;
 246         int ret;
 247
 248         /* Don't bother sending aborts for a client call once the server has
 249          * hard-ACK'd all of its request data.  After that point, we're not
 250          * going to stop the operation proceeding, and whilst we might limit
 251          * the reply, it's not worth it if we can send a new call on the same
 252          * channel instead, thereby closing off this call.
 253          */
 254         if (rxrpc_is_client_call(call) &&
 255             test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 256                 return 0;
 257
 258         spin_lock_bh(&call->lock);
 259         if (call->conn)
 260                 conn = rxrpc_get_connection_maybe(call->conn);
 261         spin_unlock_bh(&call->lock);
 262         if (!conn)
 263                 return -ECONNRESET;
 264
 265         msg.msg_name    = &call->peer->srx.transport;
 266         msg.msg_namelen = call->peer->srx.transport_len;
 267         msg.msg_control = NULL;
 268         msg.msg_controllen = 0;
 269         msg.msg_flags   = 0;
 270
 271         pkt.whdr.epoch          = htonl(conn->proto.epoch);
 272         pkt.whdr.cid            = htonl(call->cid);
 273         pkt.whdr.callNumber     = htonl(call->call_id);
 274         pkt.whdr.seq            = 0;
 275         pkt.whdr.type           = RXRPC_PACKET_TYPE_ABORT;
 276         pkt.whdr.flags          = conn->out_clientflag;
 277         pkt.whdr.userStatus     = 0;
 278         pkt.whdr.securityIndex  = call->security_ix;
 279         pkt.whdr._rsvd          = 0;
 280         pkt.whdr.serviceId      = htons(call->service_id);
 281         pkt.abort_code          = htonl(call->abort_code);
 282
 283         iov[0].iov_base = &pkt;
 284         iov[0].iov_len  = sizeof(pkt);
 285
 286         serial = atomic_inc_return(&conn->serial);
 287         pkt.whdr.serial = htonl(serial);
 288
 289         ret = kernel_sendmsg(conn->params.local->socket,
 290                              &msg, iov, 1, sizeof(pkt));
 291
 292         rxrpc_put_connection(conn);
 293         return ret;
 294 }
 295
 296 /*
 297  * send a packet through the transport endpoint
 298  */
 299 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 300                            bool retrans)
 301 {
 302         struct rxrpc_connection *conn = call->conn;
 303         struct rxrpc_wire_header whdr;
 304         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 305         struct msghdr msg;
 306         struct kvec iov[2];
 307         rxrpc_serial_t serial;
 308         size_t len;
 309         bool lost = false;
 310         int ret, opt;
 311
 312         _enter(",{%d}", skb->len);
 313
 314         /* Each transmission of a Tx packet needs a new serial number */
 315         serial = atomic_inc_return(&conn->serial);
 316
 317         whdr.epoch      = htonl(conn->proto.epoch);
 318         whdr.cid        = htonl(call->cid);
 319         whdr.callNumber = htonl(call->call_id);
 320         whdr.seq        = htonl(sp->hdr.seq);
 321         whdr.serial     = htonl(serial);
 322         whdr.type       = RXRPC_PACKET_TYPE_DATA;
 323         whdr.flags      = sp->hdr.flags;
 324         whdr.userStatus = 0;
 325         whdr.securityIndex = call->security_ix;
 326         whdr._rsvd      = htons(sp->hdr._rsvd);
 327         whdr.serviceId  = htons(call->service_id);
 328
 329         if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
 330             sp->hdr.seq == 1)
 331                 whdr.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE;
 332
 333         iov[0].iov_base = &whdr;
 334         iov[0].iov_len = sizeof(whdr);
 335         iov[1].iov_base = skb->head;
 336         iov[1].iov_len = skb->len;
 337         len = iov[0].iov_len + iov[1].iov_len;
 338
 339         msg.msg_name = &call->peer->srx.transport;
 340         msg.msg_namelen = call->peer->srx.transport_len;
 341         msg.msg_control = NULL;
 342         msg.msg_controllen = 0;
 343         msg.msg_flags = 0;
 344
 345         /* If our RTT cache needs working on, request an ACK.  Also request
 346          * ACKs if a DATA packet appears to have been lost.
 347          */
 348         if (!(sp->hdr.flags & RXRPC_LAST_PACKET) &&
 349             (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||
 350              retrans ||
 351              call->cong_mode == RXRPC_CALL_SLOW_START ||
 352              (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
 353              ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
 354                           ktime_get_real())))
 355                 whdr.flags |= RXRPC_REQUEST_ACK;
 356
 357         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 358                 static int lose;
 359                 if ((lose++ & 7) == 7) {
 360                         ret = 0;
 361                         lost = true;
 362                         goto done;
 363                 }
 364         }
 365
 366         _proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
 367
 368         /* send the packet with the don't fragment bit set if we currently
 369          * think it's small enough */
 370         if (iov[1].iov_len >= call->peer->maxdata)
 371                 goto send_fragmentable;
 372
 373         down_read(&conn->params.local->defrag_sem);
 374         /* send the packet by UDP
 375          * - returns -EMSGSIZE if UDP would have to fragment the packet
 376          *   to go out of the interface
 377          *   - in which case, we'll have processed the ICMP error
 378          *     message and update the peer record
 379          */
 380         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 381
 382         up_read(&conn->params.local->defrag_sem);
 383         if (ret == -EMSGSIZE)
 384                 goto send_fragmentable;
 385
 386 done:
 387         trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
 388                             retrans, lost);
 389         if (ret >= 0) {
 390                 ktime_t now = ktime_get_real();
 391                 skb->tstamp = now;
 392                 smp_wmb();
 393                 sp->hdr.serial = serial;
 394                 if (whdr.flags & RXRPC_REQUEST_ACK) {
 395                         call->peer->rtt_last_req = now;
 396                         trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
 397                         if (call->peer->rtt_usage > 1) {
 398                                 unsigned long nowj = jiffies, ack_lost_at;
 399
 400                                 ack_lost_at = nsecs_to_jiffies(2 * call->peer->rtt);
 401                                 if (ack_lost_at < 1)
 402                                         ack_lost_at = 1;
 403
 404                                 ack_lost_at += nowj;
 405                                 WRITE_ONCE(call->ack_lost_at, ack_lost_at);
 406                                 rxrpc_reduce_call_timer(call, ack_lost_at, nowj,
 407                                                         rxrpc_timer_set_for_lost_ack);
 408                         }
 409                 }
 410         }
 411
 412         rxrpc_set_keepalive(call);
 413
 414         _leave(" = %d [%u]", ret, call->peer->maxdata);
 415         return ret;
 416
 417 send_fragmentable:
 418         /* attempt to send this message with fragmentation enabled */
 419         _debug("send fragment");
 420
 421         down_write(&conn->params.local->defrag_sem);
 422
 423         switch (conn->params.local->srx.transport.family) {
 424         case AF_INET:
 425                 opt = IP_PMTUDISC_DONT;
 426                 ret = kernel_setsockopt(conn->params.local->socket,
 427                                         SOL_IP, IP_MTU_DISCOVER,
 428                                         (char *)&opt, sizeof(opt));
 429                 if (ret == 0) {
 430                         ret = kernel_sendmsg(conn->params.local->socket, &msg,
 431                                              iov, 2, len);
 432
 433                         opt = IP_PMTUDISC_DO;
 434                         kernel_setsockopt(conn->params.local->socket, SOL_IP,
 435                                           IP_MTU_DISCOVER,
 436                                           (char *)&opt, sizeof(opt));
 437                 }
 438                 break;
 439
 440 #ifdef CONFIG_AF_RXRPC_IPV6
 441         case AF_INET6:
 442                 opt = IPV6_PMTUDISC_DONT;
 443                 ret = kernel_setsockopt(conn->params.local->socket,
 444                                         SOL_IPV6, IPV6_MTU_DISCOVER,
 445                                         (char *)&opt, sizeof(opt));
 446                 if (ret == 0) {
 447                         ret = kernel_sendmsg(conn->params.local->socket, &msg,
 448                                              iov, 1, iov[0].iov_len);
 449
 450                         opt = IPV6_PMTUDISC_DO;
 451                         kernel_setsockopt(conn->params.local->socket,
 452                                           SOL_IPV6, IPV6_MTU_DISCOVER,
 453                                           (char *)&opt, sizeof(opt));
 454                 }
 455                 break;
 456 #endif
 457         }
 458
 459         up_write(&conn->params.local->defrag_sem);
 460         goto done;
 461 }
 462
 463 /*
 464  * reject packets through the local endpoint
 465  */
 466 void rxrpc_reject_packets(struct rxrpc_local *local)
 467 {
 468         struct sockaddr_rxrpc srx;
 469         struct rxrpc_skb_priv *sp;
 470         struct rxrpc_wire_header whdr;
 471         struct sk_buff *skb;
 472         struct msghdr msg;
 473         struct kvec iov[2];
 474         size_t size;
 475         __be32 code;
 476
 477         _enter("%d", local->debug_id);
 478
 479         iov[0].iov_base = &whdr;
 480         iov[0].iov_len = sizeof(whdr);
 481         iov[1].iov_base = &code;
 482         iov[1].iov_len = sizeof(code);
 483         size = sizeof(whdr) + sizeof(code);
 484
 485         msg.msg_name = &srx.transport;
 486         msg.msg_control = NULL;
 487         msg.msg_controllen = 0;
 488         msg.msg_flags = 0;
 489
 490         memset(&whdr, 0, sizeof(whdr));
 491         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 492
 493         while ((skb = skb_dequeue(&local->reject_queue))) {
 494                 rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 495                 sp = rxrpc_skb(skb);
 496
 497                 if (rxrpc_extract_addr_from_skb(local, &srx, skb) == 0) {
 498                         msg.msg_namelen = srx.transport_len;
 499
 500                         code = htonl(skb->priority);
 501
 502                         whdr.epoch      = htonl(sp->hdr.epoch);
 503                         whdr.cid        = htonl(sp->hdr.cid);
 504                         whdr.callNumber = htonl(sp->hdr.callNumber);
 505                         whdr.serviceId  = htons(sp->hdr.serviceId);
 506                         whdr.flags      = sp->hdr.flags;
 507                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 508                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 509
 510                         kernel_sendmsg(local->socket, &msg, iov, 2, size);
 511                 }
 512
 513                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 514         }
 515
 516         _leave("");
 517 }