net/rxrpc/input.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Processing of received RxRPC packets
   3  *
   4  * Copyright (C) 2020 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 "ar-internal.h"
  11
  12 static void rxrpc_proto_abort(const char *why,
  13                               struct rxrpc_call *call, rxrpc_seq_t seq)
  14 {
  15         if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) {
  16                 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
  17                 rxrpc_queue_call(call, rxrpc_call_queue_abort);
  18         }
  19 }
  20
  21 /*
  22  * Do TCP-style congestion management [RFC 5681].
  23  */
  24 static void rxrpc_congestion_management(struct rxrpc_call *call,
  25                                         struct sk_buff *skb,
  26                                         struct rxrpc_ack_summary *summary,
  27                                         rxrpc_serial_t acked_serial)
  28 {
  29         enum rxrpc_congest_change change = rxrpc_cong_no_change;
  30         unsigned int cumulative_acks = call->cong_cumul_acks;
  31         unsigned int cwnd = call->cong_cwnd;
  32         bool resend = false;
  33
  34         summary->flight_size =
  35                 (call->tx_top - call->acks_hard_ack) - summary->nr_acks;
  36
  37         if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
  38                 summary->retrans_timeo = true;
  39                 call->cong_ssthresh = max_t(unsigned int,
  40                                             summary->flight_size / 2, 2);
  41                 cwnd = 1;
  42                 if (cwnd >= call->cong_ssthresh &&
  43                     call->cong_mode == RXRPC_CALL_SLOW_START) {
  44                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  45                         call->cong_tstamp = skb->tstamp;
  46                         cumulative_acks = 0;
  47                 }
  48         }
  49
  50         cumulative_acks += summary->nr_new_acks;
  51         cumulative_acks += summary->nr_rot_new_acks;
  52         if (cumulative_acks > 255)
  53                 cumulative_acks = 255;
  54
  55         summary->mode = call->cong_mode;
  56         summary->cwnd = call->cong_cwnd;
  57         summary->ssthresh = call->cong_ssthresh;
  58         summary->cumulative_acks = cumulative_acks;
  59         summary->dup_acks = call->cong_dup_acks;
  60
  61         /* If we haven't transmitted anything for >1RTT, we should reset the
  62          * congestion management state.
  63          */
  64         if ((call->cong_mode == RXRPC_CALL_SLOW_START ||
  65              call->cong_mode == RXRPC_CALL_CONGEST_AVOIDANCE) &&
  66             ktime_before(ktime_add_us(call->tx_last_sent,
  67                                       call->peer->srtt_us >> 3),
  68                          ktime_get_real())
  69             ) {
  70                 change = rxrpc_cong_idle_reset;
  71                 summary->mode = RXRPC_CALL_SLOW_START;
  72                 if (RXRPC_TX_SMSS > 2190)
  73                         summary->cwnd = 2;
  74                 else if (RXRPC_TX_SMSS > 1095)
  75                         summary->cwnd = 3;
  76                 else
  77                         summary->cwnd = 4;
  78         }
  79
  80         switch (call->cong_mode) {
  81         case RXRPC_CALL_SLOW_START:
  82                 if (summary->saw_nacks)
  83                         goto packet_loss_detected;
  84                 if (summary->cumulative_acks > 0)
  85                         cwnd += 1;
  86                 if (cwnd >= call->cong_ssthresh) {
  87                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  88                         call->cong_tstamp = skb->tstamp;
  89                 }
  90                 goto out;
  91
  92         case RXRPC_CALL_CONGEST_AVOIDANCE:
  93                 if (summary->saw_nacks)
  94                         goto packet_loss_detected;
  95
  96                 /* We analyse the number of packets that get ACK'd per RTT
  97                  * period and increase the window if we managed to fill it.
  98                  */
  99                 if (call->peer->rtt_count == 0)
 100                         goto out;
 101                 if (ktime_before(skb->tstamp,
 102                                  ktime_add_us(call->cong_tstamp,
 103                                               call->peer->srtt_us >> 3)))
 104                         goto out_no_clear_ca;
 105                 change = rxrpc_cong_rtt_window_end;
 106                 call->cong_tstamp = skb->tstamp;
 107                 if (cumulative_acks >= cwnd)
 108                         cwnd++;
 109                 goto out;
 110
 111         case RXRPC_CALL_PACKET_LOSS:
 112                 if (!summary->saw_nacks)
 113                         goto resume_normality;
 114
 115                 if (summary->new_low_nack) {
 116                         change = rxrpc_cong_new_low_nack;
 117                         call->cong_dup_acks = 1;
 118                         if (call->cong_extra > 1)
 119                                 call->cong_extra = 1;
 120                         goto send_extra_data;
 121                 }
 122
 123                 call->cong_dup_acks++;
 124                 if (call->cong_dup_acks < 3)
 125                         goto send_extra_data;
 126
 127                 change = rxrpc_cong_begin_retransmission;
 128                 call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
 129                 call->cong_ssthresh = max_t(unsigned int,
 130                                             summary->flight_size / 2, 2);
 131                 cwnd = call->cong_ssthresh + 3;
 132                 call->cong_extra = 0;
 133                 call->cong_dup_acks = 0;
 134                 resend = true;
 135                 goto out;
 136
 137         case RXRPC_CALL_FAST_RETRANSMIT:
 138                 if (!summary->new_low_nack) {
 139                         if (summary->nr_new_acks == 0)
 140                                 cwnd += 1;
 141                         call->cong_dup_acks++;
 142                         if (call->cong_dup_acks == 2) {
 143                                 change = rxrpc_cong_retransmit_again;
 144                                 call->cong_dup_acks = 0;
 145                                 resend = true;
 146                         }
 147                 } else {
 148                         change = rxrpc_cong_progress;
 149                         cwnd = call->cong_ssthresh;
 150                         if (!summary->saw_nacks)
 151                                 goto resume_normality;
 152                 }
 153                 goto out;
 154
 155         default:
 156                 BUG();
 157                 goto out;
 158         }
 159
 160 resume_normality:
 161         change = rxrpc_cong_cleared_nacks;
 162         call->cong_dup_acks = 0;
 163         call->cong_extra = 0;
 164         call->cong_tstamp = skb->tstamp;
 165         if (cwnd < call->cong_ssthresh)
 166                 call->cong_mode = RXRPC_CALL_SLOW_START;
 167         else
 168                 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
 169 out:
 170         cumulative_acks = 0;
 171 out_no_clear_ca:
 172         if (cwnd >= RXRPC_TX_MAX_WINDOW)
 173                 cwnd = RXRPC_TX_MAX_WINDOW;
 174         call->cong_cwnd = cwnd;
 175         call->cong_cumul_acks = cumulative_acks;
 176         trace_rxrpc_congest(call, summary, acked_serial, change);
 177         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 178                 rxrpc_queue_call(call, rxrpc_call_queue_resend);
 179         return;
 180
 181 packet_loss_detected:
 182         change = rxrpc_cong_saw_nack;
 183         call->cong_mode = RXRPC_CALL_PACKET_LOSS;
 184         call->cong_dup_acks = 0;
 185         goto send_extra_data;
 186
 187 send_extra_data:
 188         /* Send some previously unsent DATA if we have some to advance the ACK
 189          * state.
 190          */
 191         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ||
 192             summary->nr_acks != call->tx_top - call->acks_hard_ack) {
 193                 call->cong_extra++;
 194                 wake_up(&call->waitq);
 195         }
 196         goto out_no_clear_ca;
 197 }
 198
 199 /*
 200  * Apply a hard ACK by advancing the Tx window.
 201  */
 202 static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 203                                    struct rxrpc_ack_summary *summary)
 204 {
 205         struct rxrpc_txbuf *txb;
 206         bool rot_last = false;
 207
 208         list_for_each_entry_rcu(txb, &call->tx_buffer, call_link, false) {
 209                 if (before_eq(txb->seq, call->acks_hard_ack))
 210                         continue;
 211                 summary->nr_rot_new_acks++;
 212                 if (test_bit(RXRPC_TXBUF_LAST, &txb->flags)) {
 213                         set_bit(RXRPC_CALL_TX_LAST, &call->flags);
 214                         rot_last = true;
 215                 }
 216                 if (txb->seq == to)
 217                         break;
 218         }
 219
 220         if (rot_last)
 221                 set_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags);
 222
 223         _enter("%x,%x,%x,%d", to, call->acks_hard_ack, call->tx_top, rot_last);
 224
 225         if (call->acks_lowest_nak == call->acks_hard_ack) {
 226                 call->acks_lowest_nak = to;
 227         } else if (after(to, call->acks_lowest_nak)) {
 228                 summary->new_low_nack = true;
 229                 call->acks_lowest_nak = to;
 230         }
 231
 232         smp_store_release(&call->acks_hard_ack, to);
 233
 234         trace_rxrpc_txqueue(call, (rot_last ?
 235                                    rxrpc_txqueue_rotate_last :
 236                                    rxrpc_txqueue_rotate));
 237         wake_up(&call->waitq);
 238         return rot_last;
 239 }
 240
 241 /*
 242  * End the transmission phase of a call.
 243  *
 244  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 245  * or a final ACK packet.
 246  */
 247 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 248                                const char *abort_why)
 249 {
 250         unsigned int state;
 251
 252         ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 253
 254         write_lock(&call->state_lock);
 255
 256         state = call->state;
 257         switch (state) {
 258         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 259         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 260                 if (reply_begun)
 261                         call->state = state = RXRPC_CALL_CLIENT_RECV_REPLY;
 262                 else
 263                         call->state = state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 264                 break;
 265
 266         case RXRPC_CALL_SERVER_AWAIT_ACK:
 267                 __rxrpc_call_completed(call);
 268                 state = call->state;
 269                 break;
 270
 271         default:
 272                 goto bad_state;
 273         }
 274
 275         write_unlock(&call->state_lock);
 276         if (state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 277                 trace_rxrpc_txqueue(call, rxrpc_txqueue_await_reply);
 278         else
 279                 trace_rxrpc_txqueue(call, rxrpc_txqueue_end);
 280         _leave(" = ok");
 281         return true;
 282
 283 bad_state:
 284         write_unlock(&call->state_lock);
 285         kdebug("end_tx %s", rxrpc_call_states[call->state]);
 286         rxrpc_proto_abort(abort_why, call, call->tx_top);
 287         return false;
 288 }
 289
 290 /*
 291  * Begin the reply reception phase of a call.
 292  */
 293 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 294 {
 295         struct rxrpc_ack_summary summary = { 0 };
 296         unsigned long now, timo;
 297         rxrpc_seq_t top = READ_ONCE(call->tx_top);
 298
 299         if (call->ackr_reason) {
 300                 now = jiffies;
 301                 timo = now + MAX_JIFFY_OFFSET;
 302                 WRITE_ONCE(call->resend_at, timo);
 303                 WRITE_ONCE(call->delay_ack_at, timo);
 304                 trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
 305         }
 306
 307         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 308                 if (!rxrpc_rotate_tx_window(call, top, &summary)) {
 309                         rxrpc_proto_abort("TXL", call, top);
 310                         return false;
 311                 }
 312         }
 313         return rxrpc_end_tx_phase(call, true, "ETD");
 314 }
 315
 316 static void rxrpc_input_update_ack_window(struct rxrpc_call *call,
 317                                           rxrpc_seq_t window, rxrpc_seq_t wtop)
 318 {
 319         atomic64_set_release(&call->ackr_window, ((u64)wtop) << 32 | window);
 320 }
 321
 322 /*
 323  * Push a DATA packet onto the Rx queue.
 324  */
 325 static void rxrpc_input_queue_data(struct rxrpc_call *call, struct sk_buff *skb,
 326                                    rxrpc_seq_t window, rxrpc_seq_t wtop,
 327                                    enum rxrpc_receive_trace why)
 328 {
 329         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 330         bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
 331
 332         __skb_queue_tail(&call->recvmsg_queue, skb);
 333         rxrpc_input_update_ack_window(call, window, wtop);
 334
 335         trace_rxrpc_receive(call, last ? why + 1 : why, sp->hdr.serial, sp->hdr.seq);
 336 }
 337
 338 /*
 339  * Process a DATA packet.
 340  */
 341 static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb)
 342 {
 343         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 344         struct sk_buff *oos;
 345         rxrpc_serial_t serial = sp->hdr.serial;
 346         u64 win = atomic64_read(&call->ackr_window);
 347         rxrpc_seq_t window = lower_32_bits(win);
 348         rxrpc_seq_t wtop = upper_32_bits(win);
 349         rxrpc_seq_t wlimit = window + call->rx_winsize - 1;
 350         rxrpc_seq_t seq = sp->hdr.seq;
 351         bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
 352         int ack_reason = -1;
 353
 354         rxrpc_inc_stat(call->rxnet, stat_rx_data);
 355         if (sp->hdr.flags & RXRPC_REQUEST_ACK)
 356                 rxrpc_inc_stat(call->rxnet, stat_rx_data_reqack);
 357         if (sp->hdr.flags & RXRPC_JUMBO_PACKET)
 358                 rxrpc_inc_stat(call->rxnet, stat_rx_data_jumbo);
 359
 360         if (last) {
 361                 if (test_and_set_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 362                     seq + 1 != wtop) {
 363                         rxrpc_proto_abort("LSN", call, seq);
 364                         goto err_free;
 365                 }
 366         } else {
 367                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 368                     after_eq(seq, wtop)) {
 369                         pr_warn("Packet beyond last: c=%x q=%x window=%x-%x wlimit=%x\n",
 370                                 call->debug_id, seq, window, wtop, wlimit);
 371                         rxrpc_proto_abort("LSA", call, seq);
 372                         goto err_free;
 373                 }
 374         }
 375
 376         if (after(seq, call->rx_highest_seq))
 377                 call->rx_highest_seq = seq;
 378
 379         trace_rxrpc_rx_data(call->debug_id, seq, serial, sp->hdr.flags);
 380
 381         if (before(seq, window)) {
 382                 ack_reason = RXRPC_ACK_DUPLICATE;
 383                 goto send_ack;
 384         }
 385         if (after(seq, wlimit)) {
 386                 ack_reason = RXRPC_ACK_EXCEEDS_WINDOW;
 387                 goto send_ack;
 388         }
 389
 390         /* Queue the packet. */
 391         if (seq == window) {
 392                 rxrpc_seq_t reset_from;
 393                 bool reset_sack = false;
 394
 395                 if (sp->hdr.flags & RXRPC_REQUEST_ACK)
 396                         ack_reason = RXRPC_ACK_REQUESTED;
 397                 /* Send an immediate ACK if we fill in a hole */
 398                 else if (!skb_queue_empty(&call->rx_oos_queue))
 399                         ack_reason = RXRPC_ACK_DELAY;
 400
 401                 window++;
 402                 if (after(window, wtop))
 403                         wtop = window;
 404
 405                 spin_lock(&call->recvmsg_queue.lock);
 406                 rxrpc_input_queue_data(call, skb, window, wtop, rxrpc_receive_queue);
 407                 skb = NULL;
 408
 409                 while ((oos = skb_peek(&call->rx_oos_queue))) {
 410                         struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
 411
 412                         if (after(osp->hdr.seq, window))
 413                                 break;
 414
 415                         __skb_unlink(oos, &call->rx_oos_queue);
 416                         last = osp->hdr.flags & RXRPC_LAST_PACKET;
 417                         seq = osp->hdr.seq;
 418                         if (!reset_sack) {
 419                                 reset_from = seq;
 420                                 reset_sack = true;
 421                         }
 422
 423                         window++;
 424                         rxrpc_input_queue_data(call, oos, window, wtop,
 425                                                  rxrpc_receive_queue_oos);
 426                 }
 427
 428                 spin_unlock(&call->recvmsg_queue.lock);
 429
 430                 if (reset_sack) {
 431                         do {
 432                                 call->ackr_sack_table[reset_from % RXRPC_SACK_SIZE] = 0;
 433                         } while (reset_from++, before(reset_from, window));
 434                 }
 435         } else {
 436                 bool keep = false;
 437
 438                 ack_reason = RXRPC_ACK_OUT_OF_SEQUENCE;
 439
 440                 if (!call->ackr_sack_table[seq % RXRPC_SACK_SIZE]) {
 441                         call->ackr_sack_table[seq % RXRPC_SACK_SIZE] = 1;
 442                         keep = 1;
 443                 }
 444
 445                 if (after(seq + 1, wtop)) {
 446                         wtop = seq + 1;
 447                         rxrpc_input_update_ack_window(call, window, wtop);
 448                 }
 449
 450                 if (!keep) {
 451                         ack_reason = RXRPC_ACK_DUPLICATE;
 452                         goto send_ack;
 453                 }
 454
 455                 skb_queue_walk(&call->rx_oos_queue, oos) {
 456                         struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
 457
 458                         if (after(osp->hdr.seq, seq)) {
 459                                 __skb_queue_before(&call->rx_oos_queue, oos, skb);
 460                                 goto oos_queued;
 461                         }
 462                 }
 463
 464                 __skb_queue_tail(&call->rx_oos_queue, skb);
 465         oos_queued:
 466                 trace_rxrpc_receive(call, last ? rxrpc_receive_oos_last : rxrpc_receive_oos,
 467                                     sp->hdr.serial, sp->hdr.seq);
 468                 skb = NULL;
 469         }
 470
 471 send_ack:
 472         if (ack_reason < 0 &&
 473             atomic_inc_return(&call->ackr_nr_unacked) > 2 &&
 474             test_and_set_bit(RXRPC_CALL_IDLE_ACK_PENDING, &call->flags)) {
 475                 ack_reason = RXRPC_ACK_IDLE;
 476         } else if (ack_reason >= 0) {
 477                 set_bit(RXRPC_CALL_IDLE_ACK_PENDING, &call->flags);
 478         }
 479
 480         if (ack_reason >= 0)
 481                 rxrpc_send_ACK(call, ack_reason, serial,
 482                                rxrpc_propose_ack_input_data);
 483         else
 484                 rxrpc_propose_delay_ACK(call, serial,
 485                                         rxrpc_propose_ack_input_data);
 486
 487 err_free:
 488         rxrpc_free_skb(skb, rxrpc_skb_put_input);
 489 }
 490
 491 /*
 492  * Split a jumbo packet and file the bits separately.
 493  */
 494 static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb)
 495 {
 496         struct rxrpc_jumbo_header jhdr;
 497         struct rxrpc_skb_priv *sp = rxrpc_skb(skb), *jsp;
 498         struct sk_buff *jskb;
 499         unsigned int offset = sizeof(struct rxrpc_wire_header);
 500         unsigned int len = skb->len - offset;
 501
 502         while (sp->hdr.flags & RXRPC_JUMBO_PACKET) {
 503                 if (len < RXRPC_JUMBO_SUBPKTLEN)
 504                         goto protocol_error;
 505                 if (sp->hdr.flags & RXRPC_LAST_PACKET)
 506                         goto protocol_error;
 507                 if (skb_copy_bits(skb, offset + RXRPC_JUMBO_DATALEN,
 508                                   &jhdr, sizeof(jhdr)) < 0)
 509                         goto protocol_error;
 510
 511                 jskb = skb_clone(skb, GFP_ATOMIC);
 512                 if (!jskb) {
 513                         kdebug("couldn't clone");
 514                         return false;
 515                 }
 516                 rxrpc_new_skb(jskb, rxrpc_skb_new_jumbo_subpacket);
 517                 jsp = rxrpc_skb(jskb);
 518                 jsp->offset = offset;
 519                 jsp->len = RXRPC_JUMBO_DATALEN;
 520                 rxrpc_input_data_one(call, jskb);
 521
 522                 sp->hdr.flags = jhdr.flags;
 523                 sp->hdr._rsvd = ntohs(jhdr._rsvd);
 524                 sp->hdr.seq++;
 525                 sp->hdr.serial++;
 526                 offset += RXRPC_JUMBO_SUBPKTLEN;
 527                 len -= RXRPC_JUMBO_SUBPKTLEN;
 528         }
 529
 530         sp->offset = offset;
 531         sp->len    = len;
 532         rxrpc_input_data_one(call, skb);
 533         return true;
 534
 535 protocol_error:
 536         return false;
 537 }
 538
 539 /*
 540  * Process a DATA packet, adding the packet to the Rx ring.  The caller's
 541  * packet ref must be passed on or discarded.
 542  */
 543 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 544 {
 545         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 546         enum rxrpc_call_state state;
 547         rxrpc_serial_t serial = sp->hdr.serial;
 548         rxrpc_seq_t seq0 = sp->hdr.seq;
 549
 550         _enter("{%llx,%x},{%u,%x}",
 551                atomic64_read(&call->ackr_window), call->rx_highest_seq,
 552                skb->len, seq0);
 553
 554         state = READ_ONCE(call->state);
 555         if (state >= RXRPC_CALL_COMPLETE) {
 556                 rxrpc_free_skb(skb, rxrpc_skb_put_input);
 557                 return;
 558         }
 559
 560         /* Unshare the packet so that it can be modified for in-place
 561          * decryption.
 562          */
 563         if (sp->hdr.securityIndex != 0) {
 564                 struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC);
 565                 if (!nskb) {
 566                         rxrpc_eaten_skb(skb, rxrpc_skb_eaten_by_unshare_nomem);
 567                         return;
 568                 }
 569
 570                 if (nskb != skb) {
 571                         rxrpc_eaten_skb(skb, rxrpc_skb_eaten_by_unshare);
 572                         skb = nskb;
 573                         rxrpc_new_skb(skb, rxrpc_skb_new_unshared);
 574                         sp = rxrpc_skb(skb);
 575                 }
 576         }
 577
 578         if (state == RXRPC_CALL_SERVER_RECV_REQUEST) {
 579                 unsigned long timo = READ_ONCE(call->next_req_timo);
 580                 unsigned long now, expect_req_by;
 581
 582                 if (timo) {
 583                         now = jiffies;
 584                         expect_req_by = now + timo;
 585                         WRITE_ONCE(call->expect_req_by, expect_req_by);
 586                         rxrpc_reduce_call_timer(call, expect_req_by, now,
 587                                                 rxrpc_timer_set_for_idle);
 588                 }
 589         }
 590
 591         /* Received data implicitly ACKs all of the request packets we sent
 592          * when we're acting as a client.
 593          */
 594         if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 595              state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 596             !rxrpc_receiving_reply(call))
 597                 goto out;
 598
 599         if (!rxrpc_input_split_jumbo(call, skb)) {
 600                 rxrpc_proto_abort("VLD", call, sp->hdr.seq);
 601                 goto out;
 602         }
 603         skb = NULL;
 604
 605 out:
 606         trace_rxrpc_notify_socket(call->debug_id, serial);
 607         rxrpc_notify_socket(call);
 608         rxrpc_free_skb(skb, rxrpc_skb_put_input);
 609         _leave(" [queued]");
 610 }
 611
 612 /*
 613  * See if there's a cached RTT probe to complete.
 614  */
 615 static void rxrpc_complete_rtt_probe(struct rxrpc_call *call,
 616                                      ktime_t resp_time,
 617                                      rxrpc_serial_t acked_serial,
 618                                      rxrpc_serial_t ack_serial,
 619                                      enum rxrpc_rtt_rx_trace type)
 620 {
 621         rxrpc_serial_t orig_serial;
 622         unsigned long avail;
 623         ktime_t sent_at;
 624         bool matched = false;
 625         int i;
 626
 627         avail = READ_ONCE(call->rtt_avail);
 628         smp_rmb(); /* Read avail bits before accessing data. */
 629
 630         for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) {
 631                 if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail))
 632                         continue;
 633
 634                 sent_at = call->rtt_sent_at[i];
 635                 orig_serial = call->rtt_serial[i];
 636
 637                 if (orig_serial == acked_serial) {
 638                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 639                         smp_mb(); /* Read data before setting avail bit */
 640                         set_bit(i, &call->rtt_avail);
 641                         if (type != rxrpc_rtt_rx_cancel)
 642                                 rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial,
 643                                                    sent_at, resp_time);
 644                         else
 645                                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_cancel, i,
 646                                                    orig_serial, acked_serial, 0, 0);
 647                         matched = true;
 648                 }
 649
 650                 /* If a later serial is being acked, then mark this slot as
 651                  * being available.
 652                  */
 653                 if (after(acked_serial, orig_serial)) {
 654                         trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i,
 655                                            orig_serial, acked_serial, 0, 0);
 656                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 657                         smp_wmb();
 658                         set_bit(i, &call->rtt_avail);
 659                 }
 660         }
 661
 662         if (!matched)
 663                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0);
 664 }
 665
 666 /*
 667  * Process the response to a ping that we sent to find out if we lost an ACK.
 668  *
 669  * If we got back a ping response that indicates a lower tx_top than what we
 670  * had at the time of the ping transmission, we adjudge all the DATA packets
 671  * sent between the response tx_top and the ping-time tx_top to have been lost.
 672  */
 673 static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
 674 {
 675         if (after(call->acks_lost_top, call->acks_prev_seq) &&
 676             !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 677                 rxrpc_queue_call(call, rxrpc_call_queue_resend);
 678 }
 679
 680 /*
 681  * Process a ping response.
 682  */
 683 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 684                                       ktime_t resp_time,
 685                                       rxrpc_serial_t acked_serial,
 686                                       rxrpc_serial_t ack_serial)
 687 {
 688         if (acked_serial == call->acks_lost_ping)
 689                 rxrpc_input_check_for_lost_ack(call);
 690 }
 691
 692 /*
 693  * Process the extra information that may be appended to an ACK packet
 694  */
 695 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 696                                 struct rxrpc_ackinfo *ackinfo)
 697 {
 698         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 699         struct rxrpc_peer *peer;
 700         unsigned int mtu;
 701         bool wake = false;
 702         u32 rwind = ntohl(ackinfo->rwind);
 703
 704         if (rwind > RXRPC_TX_MAX_WINDOW)
 705                 rwind = RXRPC_TX_MAX_WINDOW;
 706         if (call->tx_winsize != rwind) {
 707                 if (rwind > call->tx_winsize)
 708                         wake = true;
 709                 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake);
 710                 call->tx_winsize = rwind;
 711         }
 712
 713         if (call->cong_ssthresh > rwind)
 714                 call->cong_ssthresh = rwind;
 715
 716         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 717
 718         peer = call->peer;
 719         if (mtu < peer->maxdata) {
 720                 spin_lock_bh(&peer->lock);
 721                 peer->maxdata = mtu;
 722                 peer->mtu = mtu + peer->hdrsize;
 723                 spin_unlock_bh(&peer->lock);
 724         }
 725
 726         if (wake)
 727                 wake_up(&call->waitq);
 728 }
 729
 730 /*
 731  * Process individual soft ACKs.
 732  *
 733  * Each ACK in the array corresponds to one packet and can be either an ACK or
 734  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 735  * packets that lie beyond the end of the ACK list are scheduled for resend by
 736  * the timer on the basis that the peer might just not have processed them at
 737  * the time the ACK was sent.
 738  */
 739 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 740                                   rxrpc_seq_t seq, int nr_acks,
 741                                   struct rxrpc_ack_summary *summary)
 742 {
 743         unsigned int i;
 744
 745         for (i = 0; i < nr_acks; i++) {
 746                 if (acks[i] == RXRPC_ACK_TYPE_ACK) {
 747                         summary->nr_acks++;
 748                         summary->nr_new_acks++;
 749                 } else {
 750                         if (!summary->saw_nacks &&
 751                             call->acks_lowest_nak != seq + i) {
 752                                 call->acks_lowest_nak = seq + i;
 753                                 summary->new_low_nack = true;
 754                         }
 755                         summary->saw_nacks = true;
 756                 }
 757         }
 758 }
 759
 760 /*
 761  * Return true if the ACK is valid - ie. it doesn't appear to have regressed
 762  * with respect to the ack state conveyed by preceding ACKs.
 763  */
 764 static bool rxrpc_is_ack_valid(struct rxrpc_call *call,
 765                                rxrpc_seq_t first_pkt, rxrpc_seq_t prev_pkt)
 766 {
 767         rxrpc_seq_t base = READ_ONCE(call->acks_first_seq);
 768
 769         if (after(first_pkt, base))
 770                 return true; /* The window advanced */
 771
 772         if (before(first_pkt, base))
 773                 return false; /* firstPacket regressed */
 774
 775         if (after_eq(prev_pkt, call->acks_prev_seq))
 776                 return true; /* previousPacket hasn't regressed. */
 777
 778         /* Some rx implementations put a serial number in previousPacket. */
 779         if (after_eq(prev_pkt, base + call->tx_winsize))
 780                 return false;
 781         return true;
 782 }
 783
 784 /*
 785  * Process an ACK packet.
 786  *
 787  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 788  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 789  *
 790  * A hard-ACK means that a packet has been processed and may be discarded; a
 791  * soft-ACK means that the packet may be discarded and retransmission
 792  * requested.  A phase is complete when all packets are hard-ACK'd.
 793  */
 794 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 795 {
 796         struct rxrpc_ack_summary summary = { 0 };
 797         struct rxrpc_ackpacket ack;
 798         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 799         struct rxrpc_ackinfo info;
 800         struct sk_buff *skb_old = NULL, *skb_put = skb;
 801         rxrpc_serial_t ack_serial, acked_serial;
 802         rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
 803         int nr_acks, offset, ioffset;
 804
 805         _enter("");
 806
 807         offset = sizeof(struct rxrpc_wire_header);
 808         if (skb_copy_bits(skb, offset, &ack, sizeof(ack)) < 0) {
 809                 rxrpc_proto_abort("XAK", call, 0);
 810                 goto out;
 811         }
 812         offset += sizeof(ack);
 813
 814         ack_serial = sp->hdr.serial;
 815         acked_serial = ntohl(ack.serial);
 816         first_soft_ack = ntohl(ack.firstPacket);
 817         prev_pkt = ntohl(ack.previousPacket);
 818         hard_ack = first_soft_ack - 1;
 819         nr_acks = ack.nAcks;
 820         summary.ack_reason = (ack.reason < RXRPC_ACK__INVALID ?
 821                               ack.reason : RXRPC_ACK__INVALID);
 822
 823         trace_rxrpc_rx_ack(call, ack_serial, acked_serial,
 824                            first_soft_ack, prev_pkt,
 825                            summary.ack_reason, nr_acks);
 826         rxrpc_inc_stat(call->rxnet, stat_rx_acks[ack.reason]);
 827
 828         switch (ack.reason) {
 829         case RXRPC_ACK_PING_RESPONSE:
 830                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 831                                          rxrpc_rtt_rx_ping_response);
 832                 break;
 833         case RXRPC_ACK_REQUESTED:
 834                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 835                                          rxrpc_rtt_rx_requested_ack);
 836                 break;
 837         default:
 838                 if (acked_serial != 0)
 839                         rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 840                                                  rxrpc_rtt_rx_cancel);
 841                 break;
 842         }
 843
 844         if (ack.reason == RXRPC_ACK_PING) {
 845                 rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial,
 846                                rxrpc_propose_ack_respond_to_ping);
 847         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 848                 rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, ack_serial,
 849                                rxrpc_propose_ack_respond_to_ack);
 850         }
 851
 852         /* If we get an EXCEEDS_WINDOW ACK from the server, it probably
 853          * indicates that the client address changed due to NAT.  The server
 854          * lost the call because it switched to a different peer.
 855          */
 856         if (unlikely(ack.reason == RXRPC_ACK_EXCEEDS_WINDOW) &&
 857             first_soft_ack == 1 &&
 858             prev_pkt == 0 &&
 859             rxrpc_is_client_call(call)) {
 860                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 861                                           0, -ENETRESET);
 862                 goto out;
 863         }
 864
 865         /* If we get an OUT_OF_SEQUENCE ACK from the server, that can also
 866          * indicate a change of address.  However, we can retransmit the call
 867          * if we still have it buffered to the beginning.
 868          */
 869         if (unlikely(ack.reason == RXRPC_ACK_OUT_OF_SEQUENCE) &&
 870             first_soft_ack == 1 &&
 871             prev_pkt == 0 &&
 872             call->acks_hard_ack == 0 &&
 873             rxrpc_is_client_call(call)) {
 874                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 875                                           0, -ENETRESET);
 876                 goto out;
 877         }
 878
 879         /* Discard any out-of-order or duplicate ACKs (outside lock). */
 880         if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 881                 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 882                                            first_soft_ack, call->acks_first_seq,
 883                                            prev_pkt, call->acks_prev_seq);
 884                 goto out;
 885         }
 886
 887         info.rxMTU = 0;
 888         ioffset = offset + nr_acks + 3;
 889         if (skb->len >= ioffset + sizeof(info) &&
 890             skb_copy_bits(skb, ioffset, &info, sizeof(info)) < 0) {
 891                 rxrpc_proto_abort("XAI", call, 0);
 892                 goto out;
 893         }
 894
 895         if (nr_acks > 0)
 896                 skb_condense(skb);
 897
 898         /* Discard any out-of-order or duplicate ACKs (inside lock). */
 899         if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 900                 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 901                                            first_soft_ack, call->acks_first_seq,
 902                                            prev_pkt, call->acks_prev_seq);
 903                 goto out;
 904         }
 905         call->acks_latest_ts = skb->tstamp;
 906
 907         call->acks_first_seq = first_soft_ack;
 908         call->acks_prev_seq = prev_pkt;
 909
 910         switch (ack.reason) {
 911         case RXRPC_ACK_PING:
 912                 break;
 913         case RXRPC_ACK_PING_RESPONSE:
 914                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 915                                           ack_serial);
 916                 fallthrough;
 917         default:
 918                 if (after(acked_serial, call->acks_highest_serial))
 919                         call->acks_highest_serial = acked_serial;
 920                 break;
 921         }
 922
 923         /* Parse rwind and mtu sizes if provided. */
 924         if (info.rxMTU)
 925                 rxrpc_input_ackinfo(call, skb, &info);
 926
 927         if (first_soft_ack == 0) {
 928                 rxrpc_proto_abort("AK0", call, 0);
 929                 goto out;
 930         }
 931
 932         /* Ignore ACKs unless we are or have just been transmitting. */
 933         switch (READ_ONCE(call->state)) {
 934         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 935         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 936         case RXRPC_CALL_SERVER_SEND_REPLY:
 937         case RXRPC_CALL_SERVER_AWAIT_ACK:
 938                 break;
 939         default:
 940                 goto out;
 941         }
 942
 943         if (before(hard_ack, call->acks_hard_ack) ||
 944             after(hard_ack, call->tx_top)) {
 945                 rxrpc_proto_abort("AKW", call, 0);
 946                 goto out;
 947         }
 948         if (nr_acks > call->tx_top - hard_ack) {
 949                 rxrpc_proto_abort("AKN", call, 0);
 950                 goto out;
 951         }
 952
 953         if (after(hard_ack, call->acks_hard_ack)) {
 954                 if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
 955                         rxrpc_end_tx_phase(call, false, "ETA");
 956                         goto out;
 957                 }
 958         }
 959
 960         if (nr_acks > 0) {
 961                 if (offset > (int)skb->len - nr_acks) {
 962                         rxrpc_proto_abort("XSA", call, 0);
 963                         goto out;
 964                 }
 965
 966                 spin_lock(&call->acks_ack_lock);
 967                 skb_old = call->acks_soft_tbl;
 968                 call->acks_soft_tbl = skb;
 969                 spin_unlock(&call->acks_ack_lock);
 970
 971                 rxrpc_input_soft_acks(call, skb->data + offset, first_soft_ack,
 972                                       nr_acks, &summary);
 973                 skb_put = NULL;
 974         } else if (call->acks_soft_tbl) {
 975                 spin_lock(&call->acks_ack_lock);
 976                 skb_old = call->acks_soft_tbl;
 977                 call->acks_soft_tbl = NULL;
 978                 spin_unlock(&call->acks_ack_lock);
 979         }
 980
 981         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) &&
 982             summary.nr_acks == call->tx_top - hard_ack &&
 983             rxrpc_is_client_call(call))
 984                 rxrpc_propose_ping(call, ack_serial,
 985                                    rxrpc_propose_ack_ping_for_lost_reply);
 986
 987         rxrpc_congestion_management(call, skb, &summary, acked_serial);
 988 out:
 989         rxrpc_free_skb(skb_put, rxrpc_skb_put_input);
 990         rxrpc_free_skb(skb_old, rxrpc_skb_put_ack);
 991 }
 992
 993 /*
 994  * Process an ACKALL packet.
 995  */
 996 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 997 {
 998         struct rxrpc_ack_summary summary = { 0 };
 999
1000         if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
1001                 rxrpc_end_tx_phase(call, false, "ETL");
1002 }
1003
1004 /*
1005  * Process an ABORT packet directed at a call.
1006  */
1007 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
1008 {
1009         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1010
1011         trace_rxrpc_rx_abort(call, sp->hdr.serial, skb->priority);
1012
1013         rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
1014                                   skb->priority, -ECONNABORTED);
1015 }
1016
1017 /*
1018  * Process an incoming call packet.
1019  */
1020 void rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb)
1021 {
1022         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1023         unsigned long timo;
1024
1025         _enter("%p,%p", call, skb);
1026
1027         timo = READ_ONCE(call->next_rx_timo);
1028         if (timo) {
1029                 unsigned long now = jiffies, expect_rx_by;
1030
1031                 expect_rx_by = now + timo;
1032                 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
1033                 rxrpc_reduce_call_timer(call, expect_rx_by, now,
1034                                         rxrpc_timer_set_for_normal);
1035         }
1036
1037         switch (sp->hdr.type) {
1038         case RXRPC_PACKET_TYPE_DATA:
1039                 rxrpc_input_data(call, skb);
1040                 goto no_free;
1041
1042         case RXRPC_PACKET_TYPE_ACK:
1043                 rxrpc_input_ack(call, skb);
1044                 goto no_free;
1045
1046         case RXRPC_PACKET_TYPE_BUSY:
1047                 /* Just ignore BUSY packets from the server; the retry and
1048                  * lifespan timers will take care of business.  BUSY packets
1049                  * from the client don't make sense.
1050                  */
1051                 break;
1052
1053         case RXRPC_PACKET_TYPE_ABORT:
1054                 rxrpc_input_abort(call, skb);
1055                 break;
1056
1057         case RXRPC_PACKET_TYPE_ACKALL:
1058                 rxrpc_input_ackall(call, skb);
1059                 break;
1060
1061         default:
1062                 break;
1063         }
1064
1065         rxrpc_free_skb(skb, rxrpc_skb_put_input);
1066 no_free:
1067         _leave("");
1068 }
1069
1070 /*
1071  * Handle a new service call on a channel implicitly completing the preceding
1072  * call on that channel.  This does not apply to client conns.
1073  *
1074  * TODO: If callNumber > call_id + 1, renegotiate security.
1075  */
1076 void rxrpc_input_implicit_end_call(struct rxrpc_sock *rx,
1077                                    struct rxrpc_connection *conn,
1078                                    struct rxrpc_call *call)
1079 {
1080         switch (READ_ONCE(call->state)) {
1081         case RXRPC_CALL_SERVER_AWAIT_ACK:
1082                 rxrpc_call_completed(call);
1083                 fallthrough;
1084         case RXRPC_CALL_COMPLETE:
1085                 break;
1086         default:
1087                 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
1088                         set_bit(RXRPC_CALL_EV_ABORT, &call->events);
1089                         rxrpc_queue_call(call, rxrpc_call_queue_abort);
1090                 }
1091                 trace_rxrpc_improper_term(call);
1092                 break;
1093         }
1094
1095         spin_lock(&rx->incoming_lock);
1096         __rxrpc_disconnect_call(conn, call);
1097         spin_unlock(&rx->incoming_lock);
1098 }