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(struct rxrpc_call *call, rxrpc_seq_t seq,
  13                               enum rxrpc_abort_reason why)
  14 {
  15         rxrpc_abort_call(call, seq, RX_PROTOCOL_ERROR, -EBADMSG, why);
  16 }
  17
  18 /*
  19  * Do TCP-style congestion management [RFC 5681].
  20  */
  21 static void rxrpc_congestion_management(struct rxrpc_call *call,
  22                                         struct sk_buff *skb,
  23                                         struct rxrpc_ack_summary *summary,
  24                                         rxrpc_serial_t acked_serial)
  25 {
  26         enum rxrpc_congest_change change = rxrpc_cong_no_change;
  27         unsigned int cumulative_acks = call->cong_cumul_acks;
  28         unsigned int cwnd = call->cong_cwnd;
  29         bool resend = false;
  30
  31         summary->flight_size =
  32                 (call->tx_top - call->acks_hard_ack) - summary->nr_acks;
  33
  34         if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
  35                 summary->retrans_timeo = true;
  36                 call->cong_ssthresh = max_t(unsigned int,
  37                                             summary->flight_size / 2, 2);
  38                 cwnd = 1;
  39                 if (cwnd >= call->cong_ssthresh &&
  40                     call->cong_mode == RXRPC_CALL_SLOW_START) {
  41                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  42                         call->cong_tstamp = skb->tstamp;
  43                         cumulative_acks = 0;
  44                 }
  45         }
  46
  47         cumulative_acks += summary->nr_new_acks;
  48         cumulative_acks += summary->nr_rot_new_acks;
  49         if (cumulative_acks > 255)
  50                 cumulative_acks = 255;
  51
  52         summary->mode = call->cong_mode;
  53         summary->cwnd = call->cong_cwnd;
  54         summary->ssthresh = call->cong_ssthresh;
  55         summary->cumulative_acks = cumulative_acks;
  56         summary->dup_acks = call->cong_dup_acks;
  57
  58         switch (call->cong_mode) {
  59         case RXRPC_CALL_SLOW_START:
  60                 if (summary->saw_nacks)
  61                         goto packet_loss_detected;
  62                 if (summary->cumulative_acks > 0)
  63                         cwnd += 1;
  64                 if (cwnd >= call->cong_ssthresh) {
  65                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  66                         call->cong_tstamp = skb->tstamp;
  67                 }
  68                 goto out;
  69
  70         case RXRPC_CALL_CONGEST_AVOIDANCE:
  71                 if (summary->saw_nacks)
  72                         goto packet_loss_detected;
  73
  74                 /* We analyse the number of packets that get ACK'd per RTT
  75                  * period and increase the window if we managed to fill it.
  76                  */
  77                 if (call->peer->rtt_count == 0)
  78                         goto out;
  79                 if (ktime_before(skb->tstamp,
  80                                  ktime_add_us(call->cong_tstamp,
  81                                               call->peer->srtt_us >> 3)))
  82                         goto out_no_clear_ca;
  83                 change = rxrpc_cong_rtt_window_end;
  84                 call->cong_tstamp = skb->tstamp;
  85                 if (cumulative_acks >= cwnd)
  86                         cwnd++;
  87                 goto out;
  88
  89         case RXRPC_CALL_PACKET_LOSS:
  90                 if (!summary->saw_nacks)
  91                         goto resume_normality;
  92
  93                 if (summary->new_low_nack) {
  94                         change = rxrpc_cong_new_low_nack;
  95                         call->cong_dup_acks = 1;
  96                         if (call->cong_extra > 1)
  97                                 call->cong_extra = 1;
  98                         goto send_extra_data;
  99                 }
 100
 101                 call->cong_dup_acks++;
 102                 if (call->cong_dup_acks < 3)
 103                         goto send_extra_data;
 104
 105                 change = rxrpc_cong_begin_retransmission;
 106                 call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
 107                 call->cong_ssthresh = max_t(unsigned int,
 108                                             summary->flight_size / 2, 2);
 109                 cwnd = call->cong_ssthresh + 3;
 110                 call->cong_extra = 0;
 111                 call->cong_dup_acks = 0;
 112                 resend = true;
 113                 goto out;
 114
 115         case RXRPC_CALL_FAST_RETRANSMIT:
 116                 if (!summary->new_low_nack) {
 117                         if (summary->nr_new_acks == 0)
 118                                 cwnd += 1;
 119                         call->cong_dup_acks++;
 120                         if (call->cong_dup_acks == 2) {
 121                                 change = rxrpc_cong_retransmit_again;
 122                                 call->cong_dup_acks = 0;
 123                                 resend = true;
 124                         }
 125                 } else {
 126                         change = rxrpc_cong_progress;
 127                         cwnd = call->cong_ssthresh;
 128                         if (!summary->saw_nacks)
 129                                 goto resume_normality;
 130                 }
 131                 goto out;
 132
 133         default:
 134                 BUG();
 135                 goto out;
 136         }
 137
 138 resume_normality:
 139         change = rxrpc_cong_cleared_nacks;
 140         call->cong_dup_acks = 0;
 141         call->cong_extra = 0;
 142         call->cong_tstamp = skb->tstamp;
 143         if (cwnd < call->cong_ssthresh)
 144                 call->cong_mode = RXRPC_CALL_SLOW_START;
 145         else
 146                 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
 147 out:
 148         cumulative_acks = 0;
 149 out_no_clear_ca:
 150         if (cwnd >= RXRPC_TX_MAX_WINDOW)
 151                 cwnd = RXRPC_TX_MAX_WINDOW;
 152         call->cong_cwnd = cwnd;
 153         call->cong_cumul_acks = cumulative_acks;
 154         trace_rxrpc_congest(call, summary, acked_serial, change);
 155         if (resend)
 156                 rxrpc_resend(call, skb);
 157         return;
 158
 159 packet_loss_detected:
 160         change = rxrpc_cong_saw_nack;
 161         call->cong_mode = RXRPC_CALL_PACKET_LOSS;
 162         call->cong_dup_acks = 0;
 163         goto send_extra_data;
 164
 165 send_extra_data:
 166         /* Send some previously unsent DATA if we have some to advance the ACK
 167          * state.
 168          */
 169         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ||
 170             summary->nr_acks != call->tx_top - call->acks_hard_ack) {
 171                 call->cong_extra++;
 172                 wake_up(&call->waitq);
 173         }
 174         goto out_no_clear_ca;
 175 }
 176
 177 /*
 178  * Degrade the congestion window if we haven't transmitted a packet for >1RTT.
 179  */
 180 void rxrpc_congestion_degrade(struct rxrpc_call *call)
 181 {
 182         ktime_t rtt, now;
 183
 184         if (call->cong_mode != RXRPC_CALL_SLOW_START &&
 185             call->cong_mode != RXRPC_CALL_CONGEST_AVOIDANCE)
 186                 return;
 187         if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 188                 return;
 189
 190         rtt = ns_to_ktime(call->peer->srtt_us * (1000 / 8));
 191         now = ktime_get_real();
 192         if (!ktime_before(ktime_add(call->tx_last_sent, rtt), now))
 193                 return;
 194
 195         trace_rxrpc_reset_cwnd(call, now);
 196         rxrpc_inc_stat(call->rxnet, stat_tx_data_cwnd_reset);
 197         call->tx_last_sent = now;
 198         call->cong_mode = RXRPC_CALL_SLOW_START;
 199         call->cong_ssthresh = max_t(unsigned int, call->cong_ssthresh,
 200                                     call->cong_cwnd * 3 / 4);
 201         call->cong_cwnd = max_t(unsigned int, call->cong_cwnd / 2, RXRPC_MIN_CWND);
 202 }
 203
 204 /*
 205  * Apply a hard ACK by advancing the Tx window.
 206  */
 207 static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 208                                    struct rxrpc_ack_summary *summary)
 209 {
 210         struct rxrpc_txbuf *txb;
 211         bool rot_last = false;
 212
 213         list_for_each_entry_rcu(txb, &call->tx_buffer, call_link, false) {
 214                 if (before_eq(txb->seq, call->acks_hard_ack))
 215                         continue;
 216                 summary->nr_rot_new_acks++;
 217                 if (test_bit(RXRPC_TXBUF_LAST, &txb->flags)) {
 218                         set_bit(RXRPC_CALL_TX_LAST, &call->flags);
 219                         rot_last = true;
 220                 }
 221                 if (txb->seq == to)
 222                         break;
 223         }
 224
 225         if (rot_last)
 226                 set_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags);
 227
 228         _enter("%x,%x,%x,%d", to, call->acks_hard_ack, call->tx_top, rot_last);
 229
 230         if (call->acks_lowest_nak == call->acks_hard_ack) {
 231                 call->acks_lowest_nak = to;
 232         } else if (after(to, call->acks_lowest_nak)) {
 233                 summary->new_low_nack = true;
 234                 call->acks_lowest_nak = to;
 235         }
 236
 237         smp_store_release(&call->acks_hard_ack, to);
 238
 239         trace_rxrpc_txqueue(call, (rot_last ?
 240                                    rxrpc_txqueue_rotate_last :
 241                                    rxrpc_txqueue_rotate));
 242         wake_up(&call->waitq);
 243         return rot_last;
 244 }
 245
 246 /*
 247  * End the transmission phase of a call.
 248  *
 249  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 250  * or a final ACK packet.
 251  */
 252 static void rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 253                                enum rxrpc_abort_reason abort_why)
 254 {
 255         unsigned int state;
 256
 257         ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 258
 259         write_lock(&call->state_lock);
 260
 261         state = call->state;
 262         switch (state) {
 263         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 264         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 265                 if (reply_begun)
 266                         call->state = state = RXRPC_CALL_CLIENT_RECV_REPLY;
 267                 else
 268                         call->state = state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 269                 break;
 270
 271         case RXRPC_CALL_SERVER_AWAIT_ACK:
 272                 __rxrpc_call_completed(call);
 273                 state = call->state;
 274                 break;
 275
 276         default:
 277                 goto bad_state;
 278         }
 279
 280         write_unlock(&call->state_lock);
 281         if (state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 282                 trace_rxrpc_txqueue(call, rxrpc_txqueue_await_reply);
 283         else
 284                 trace_rxrpc_txqueue(call, rxrpc_txqueue_end);
 285         _leave(" = ok");
 286         return;
 287
 288 bad_state:
 289         write_unlock(&call->state_lock);
 290         kdebug("end_tx %s", rxrpc_call_states[call->state]);
 291         rxrpc_proto_abort(call, call->tx_top, abort_why);
 292 }
 293
 294 /*
 295  * Begin the reply reception phase of a call.
 296  */
 297 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 298 {
 299         struct rxrpc_ack_summary summary = { 0 };
 300         unsigned long now, timo;
 301         rxrpc_seq_t top = READ_ONCE(call->tx_top);
 302
 303         if (call->ackr_reason) {
 304                 now = jiffies;
 305                 timo = now + MAX_JIFFY_OFFSET;
 306                 WRITE_ONCE(call->resend_at, timo);
 307                 WRITE_ONCE(call->delay_ack_at, timo);
 308                 trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
 309         }
 310
 311         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 312                 if (!rxrpc_rotate_tx_window(call, top, &summary)) {
 313                         rxrpc_proto_abort(call, top, rxrpc_eproto_early_reply);
 314                         return false;
 315                 }
 316         }
 317
 318         rxrpc_end_tx_phase(call, true, rxrpc_eproto_unexpected_reply);
 319         return true;
 320 }
 321
 322 /*
 323  * End the packet reception phase.
 324  */
 325 static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial)
 326 {
 327         rxrpc_seq_t whigh = READ_ONCE(call->rx_highest_seq);
 328
 329         _enter("%d,%s", call->debug_id, rxrpc_call_states[call->state]);
 330
 331         trace_rxrpc_receive(call, rxrpc_receive_end, 0, whigh);
 332
 333         if (rxrpc_call_state(call) == RXRPC_CALL_CLIENT_RECV_REPLY)
 334                 rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_terminal_ack);
 335
 336         write_lock(&call->state_lock);
 337
 338         switch (call->state) {
 339         case RXRPC_CALL_CLIENT_RECV_REPLY:
 340                 __rxrpc_call_completed(call);
 341                 write_unlock(&call->state_lock);
 342                 break;
 343
 344         case RXRPC_CALL_SERVER_RECV_REQUEST:
 345                 call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
 346                 call->expect_req_by = jiffies + MAX_JIFFY_OFFSET;
 347                 write_unlock(&call->state_lock);
 348                 rxrpc_propose_delay_ACK(call, serial,
 349                                         rxrpc_propose_ack_processing_op);
 350                 break;
 351         default:
 352                 write_unlock(&call->state_lock);
 353                 break;
 354         }
 355 }
 356
 357 static void rxrpc_input_update_ack_window(struct rxrpc_call *call,
 358                                           rxrpc_seq_t window, rxrpc_seq_t wtop)
 359 {
 360         atomic64_set_release(&call->ackr_window, ((u64)wtop) << 32 | window);
 361 }
 362
 363 /*
 364  * Push a DATA packet onto the Rx queue.
 365  */
 366 static void rxrpc_input_queue_data(struct rxrpc_call *call, struct sk_buff *skb,
 367                                    rxrpc_seq_t window, rxrpc_seq_t wtop,
 368                                    enum rxrpc_receive_trace why)
 369 {
 370         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 371         bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
 372
 373         __skb_queue_tail(&call->recvmsg_queue, skb);
 374         rxrpc_input_update_ack_window(call, window, wtop);
 375         trace_rxrpc_receive(call, last ? why + 1 : why, sp->hdr.serial, sp->hdr.seq);
 376         if (last)
 377                 rxrpc_end_rx_phase(call, sp->hdr.serial);
 378 }
 379
 380 /*
 381  * Process a DATA packet.
 382  */
 383 static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb,
 384                                  bool *_notify)
 385 {
 386         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 387         struct sk_buff *oos;
 388         rxrpc_serial_t serial = sp->hdr.serial;
 389         u64 win = atomic64_read(&call->ackr_window);
 390         rxrpc_seq_t window = lower_32_bits(win);
 391         rxrpc_seq_t wtop = upper_32_bits(win);
 392         rxrpc_seq_t wlimit = window + call->rx_winsize - 1;
 393         rxrpc_seq_t seq = sp->hdr.seq;
 394         bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
 395         int ack_reason = -1;
 396
 397         rxrpc_inc_stat(call->rxnet, stat_rx_data);
 398         if (sp->hdr.flags & RXRPC_REQUEST_ACK)
 399                 rxrpc_inc_stat(call->rxnet, stat_rx_data_reqack);
 400         if (sp->hdr.flags & RXRPC_JUMBO_PACKET)
 401                 rxrpc_inc_stat(call->rxnet, stat_rx_data_jumbo);
 402
 403         if (last) {
 404                 if (test_and_set_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 405                     seq + 1 != wtop)
 406                         return rxrpc_proto_abort(call, seq, rxrpc_eproto_different_last);
 407         } else {
 408                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 409                     after_eq(seq, wtop)) {
 410                         pr_warn("Packet beyond last: c=%x q=%x window=%x-%x wlimit=%x\n",
 411                                 call->debug_id, seq, window, wtop, wlimit);
 412                         return rxrpc_proto_abort(call, seq, rxrpc_eproto_data_after_last);
 413                 }
 414         }
 415
 416         if (after(seq, call->rx_highest_seq))
 417                 call->rx_highest_seq = seq;
 418
 419         trace_rxrpc_rx_data(call->debug_id, seq, serial, sp->hdr.flags);
 420
 421         if (before(seq, window)) {
 422                 ack_reason = RXRPC_ACK_DUPLICATE;
 423                 goto send_ack;
 424         }
 425         if (after(seq, wlimit)) {
 426                 ack_reason = RXRPC_ACK_EXCEEDS_WINDOW;
 427                 goto send_ack;
 428         }
 429
 430         /* Queue the packet. */
 431         if (seq == window) {
 432                 rxrpc_seq_t reset_from;
 433                 bool reset_sack = false;
 434
 435                 if (sp->hdr.flags & RXRPC_REQUEST_ACK)
 436                         ack_reason = RXRPC_ACK_REQUESTED;
 437                 /* Send an immediate ACK if we fill in a hole */
 438                 else if (!skb_queue_empty(&call->rx_oos_queue))
 439                         ack_reason = RXRPC_ACK_DELAY;
 440                 else
 441                         atomic_inc_return(&call->ackr_nr_unacked);
 442
 443                 window++;
 444                 if (after(window, wtop))
 445                         wtop = window;
 446
 447                 rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg);
 448
 449                 spin_lock(&call->recvmsg_queue.lock);
 450                 rxrpc_input_queue_data(call, skb, window, wtop, rxrpc_receive_queue);
 451                 *_notify = true;
 452
 453                 while ((oos = skb_peek(&call->rx_oos_queue))) {
 454                         struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
 455
 456                         if (after(osp->hdr.seq, window))
 457                                 break;
 458
 459                         __skb_unlink(oos, &call->rx_oos_queue);
 460                         last = osp->hdr.flags & RXRPC_LAST_PACKET;
 461                         seq = osp->hdr.seq;
 462                         if (!reset_sack) {
 463                                 reset_from = seq;
 464                                 reset_sack = true;
 465                         }
 466
 467                         window++;
 468                         rxrpc_input_queue_data(call, oos, window, wtop,
 469                                                  rxrpc_receive_queue_oos);
 470                 }
 471
 472                 spin_unlock(&call->recvmsg_queue.lock);
 473
 474                 if (reset_sack) {
 475                         do {
 476                                 call->ackr_sack_table[reset_from % RXRPC_SACK_SIZE] = 0;
 477                         } while (reset_from++, before(reset_from, window));
 478                 }
 479         } else {
 480                 bool keep = false;
 481
 482                 ack_reason = RXRPC_ACK_OUT_OF_SEQUENCE;
 483
 484                 if (!call->ackr_sack_table[seq % RXRPC_SACK_SIZE]) {
 485                         call->ackr_sack_table[seq % RXRPC_SACK_SIZE] = 1;
 486                         keep = 1;
 487                 }
 488
 489                 if (after(seq + 1, wtop)) {
 490                         wtop = seq + 1;
 491                         rxrpc_input_update_ack_window(call, window, wtop);
 492                 }
 493
 494                 if (!keep) {
 495                         ack_reason = RXRPC_ACK_DUPLICATE;
 496                         goto send_ack;
 497                 }
 498
 499                 skb_queue_walk(&call->rx_oos_queue, oos) {
 500                         struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
 501
 502                         if (after(osp->hdr.seq, seq)) {
 503                                 rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos);
 504                                 __skb_queue_before(&call->rx_oos_queue, oos, skb);
 505                                 goto oos_queued;
 506                         }
 507                 }
 508
 509                 rxrpc_get_skb(skb, rxrpc_skb_get_to_recvmsg_oos);
 510                 __skb_queue_tail(&call->rx_oos_queue, skb);
 511         oos_queued:
 512                 trace_rxrpc_receive(call, last ? rxrpc_receive_oos_last : rxrpc_receive_oos,
 513                                     sp->hdr.serial, sp->hdr.seq);
 514         }
 515
 516 send_ack:
 517         if (ack_reason >= 0)
 518                 rxrpc_send_ACK(call, ack_reason, serial,
 519                                rxrpc_propose_ack_input_data);
 520         else
 521                 rxrpc_propose_delay_ACK(call, serial,
 522                                         rxrpc_propose_ack_input_data);
 523 }
 524
 525 /*
 526  * Split a jumbo packet and file the bits separately.
 527  */
 528 static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb)
 529 {
 530         struct rxrpc_jumbo_header jhdr;
 531         struct rxrpc_skb_priv *sp = rxrpc_skb(skb), *jsp;
 532         struct sk_buff *jskb;
 533         unsigned int offset = sizeof(struct rxrpc_wire_header);
 534         unsigned int len = skb->len - offset;
 535         bool notify = false;
 536
 537         while (sp->hdr.flags & RXRPC_JUMBO_PACKET) {
 538                 if (len < RXRPC_JUMBO_SUBPKTLEN)
 539                         goto protocol_error;
 540                 if (sp->hdr.flags & RXRPC_LAST_PACKET)
 541                         goto protocol_error;
 542                 if (skb_copy_bits(skb, offset + RXRPC_JUMBO_DATALEN,
 543                                   &jhdr, sizeof(jhdr)) < 0)
 544                         goto protocol_error;
 545
 546                 jskb = skb_clone(skb, GFP_NOFS);
 547                 if (!jskb) {
 548                         kdebug("couldn't clone");
 549                         return false;
 550                 }
 551                 rxrpc_new_skb(jskb, rxrpc_skb_new_jumbo_subpacket);
 552                 jsp = rxrpc_skb(jskb);
 553                 jsp->offset = offset;
 554                 jsp->len = RXRPC_JUMBO_DATALEN;
 555                 rxrpc_input_data_one(call, jskb, &notify);
 556                 rxrpc_free_skb(jskb, rxrpc_skb_put_jumbo_subpacket);
 557
 558                 sp->hdr.flags = jhdr.flags;
 559                 sp->hdr._rsvd = ntohs(jhdr._rsvd);
 560                 sp->hdr.seq++;
 561                 sp->hdr.serial++;
 562                 offset += RXRPC_JUMBO_SUBPKTLEN;
 563                 len -= RXRPC_JUMBO_SUBPKTLEN;
 564         }
 565
 566         sp->offset = offset;
 567         sp->len    = len;
 568         rxrpc_input_data_one(call, skb, &notify);
 569         if (notify) {
 570                 trace_rxrpc_notify_socket(call->debug_id, sp->hdr.serial);
 571                 rxrpc_notify_socket(call);
 572         }
 573         return true;
 574
 575 protocol_error:
 576         return false;
 577 }
 578
 579 /*
 580  * Process a DATA packet, adding the packet to the Rx ring.  The caller's
 581  * packet ref must be passed on or discarded.
 582  */
 583 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 584 {
 585         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 586         enum rxrpc_call_state state;
 587         rxrpc_serial_t serial = sp->hdr.serial;
 588         rxrpc_seq_t seq0 = sp->hdr.seq;
 589
 590         _enter("{%llx,%x},{%u,%x}",
 591                atomic64_read(&call->ackr_window), call->rx_highest_seq,
 592                skb->len, seq0);
 593
 594         state = READ_ONCE(call->state);
 595         if (state >= RXRPC_CALL_COMPLETE)
 596                 return;
 597
 598         if (state == RXRPC_CALL_SERVER_RECV_REQUEST) {
 599                 unsigned long timo = READ_ONCE(call->next_req_timo);
 600                 unsigned long now, expect_req_by;
 601
 602                 if (timo) {
 603                         now = jiffies;
 604                         expect_req_by = now + timo;
 605                         WRITE_ONCE(call->expect_req_by, expect_req_by);
 606                         rxrpc_reduce_call_timer(call, expect_req_by, now,
 607                                                 rxrpc_timer_set_for_idle);
 608                 }
 609         }
 610
 611         /* Received data implicitly ACKs all of the request packets we sent
 612          * when we're acting as a client.
 613          */
 614         if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 615              state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 616             !rxrpc_receiving_reply(call))
 617                 goto out_notify;
 618
 619         if (!rxrpc_input_split_jumbo(call, skb)) {
 620                 rxrpc_proto_abort(call, sp->hdr.seq, rxrpc_badmsg_bad_jumbo);
 621                 goto out_notify;
 622         }
 623         skb = NULL;
 624
 625 out_notify:
 626         trace_rxrpc_notify_socket(call->debug_id, serial);
 627         rxrpc_notify_socket(call);
 628         _leave(" [queued]");
 629 }
 630
 631 /*
 632  * See if there's a cached RTT probe to complete.
 633  */
 634 static void rxrpc_complete_rtt_probe(struct rxrpc_call *call,
 635                                      ktime_t resp_time,
 636                                      rxrpc_serial_t acked_serial,
 637                                      rxrpc_serial_t ack_serial,
 638                                      enum rxrpc_rtt_rx_trace type)
 639 {
 640         rxrpc_serial_t orig_serial;
 641         unsigned long avail;
 642         ktime_t sent_at;
 643         bool matched = false;
 644         int i;
 645
 646         avail = READ_ONCE(call->rtt_avail);
 647         smp_rmb(); /* Read avail bits before accessing data. */
 648
 649         for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) {
 650                 if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail))
 651                         continue;
 652
 653                 sent_at = call->rtt_sent_at[i];
 654                 orig_serial = call->rtt_serial[i];
 655
 656                 if (orig_serial == acked_serial) {
 657                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 658                         smp_mb(); /* Read data before setting avail bit */
 659                         set_bit(i, &call->rtt_avail);
 660                         if (type != rxrpc_rtt_rx_cancel)
 661                                 rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial,
 662                                                    sent_at, resp_time);
 663                         else
 664                                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_cancel, i,
 665                                                    orig_serial, acked_serial, 0, 0);
 666                         matched = true;
 667                 }
 668
 669                 /* If a later serial is being acked, then mark this slot as
 670                  * being available.
 671                  */
 672                 if (after(acked_serial, orig_serial)) {
 673                         trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i,
 674                                            orig_serial, acked_serial, 0, 0);
 675                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 676                         smp_wmb();
 677                         set_bit(i, &call->rtt_avail);
 678                 }
 679         }
 680
 681         if (!matched)
 682                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0);
 683 }
 684
 685 /*
 686  * Process the extra information that may be appended to an ACK packet
 687  */
 688 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 689                                 struct rxrpc_ackinfo *ackinfo)
 690 {
 691         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 692         struct rxrpc_peer *peer;
 693         unsigned int mtu;
 694         bool wake = false;
 695         u32 rwind = ntohl(ackinfo->rwind);
 696
 697         if (rwind > RXRPC_TX_MAX_WINDOW)
 698                 rwind = RXRPC_TX_MAX_WINDOW;
 699         if (call->tx_winsize != rwind) {
 700                 if (rwind > call->tx_winsize)
 701                         wake = true;
 702                 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake);
 703                 call->tx_winsize = rwind;
 704         }
 705
 706         if (call->cong_ssthresh > rwind)
 707                 call->cong_ssthresh = rwind;
 708
 709         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 710
 711         peer = call->peer;
 712         if (mtu < peer->maxdata) {
 713                 spin_lock(&peer->lock);
 714                 peer->maxdata = mtu;
 715                 peer->mtu = mtu + peer->hdrsize;
 716                 spin_unlock(&peer->lock);
 717         }
 718
 719         if (wake)
 720                 wake_up(&call->waitq);
 721 }
 722
 723 /*
 724  * Process individual soft ACKs.
 725  *
 726  * Each ACK in the array corresponds to one packet and can be either an ACK or
 727  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 728  * packets that lie beyond the end of the ACK list are scheduled for resend by
 729  * the timer on the basis that the peer might just not have processed them at
 730  * the time the ACK was sent.
 731  */
 732 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 733                                   rxrpc_seq_t seq, int nr_acks,
 734                                   struct rxrpc_ack_summary *summary)
 735 {
 736         unsigned int i;
 737
 738         for (i = 0; i < nr_acks; i++) {
 739                 if (acks[i] == RXRPC_ACK_TYPE_ACK) {
 740                         summary->nr_acks++;
 741                         summary->nr_new_acks++;
 742                 } else {
 743                         if (!summary->saw_nacks &&
 744                             call->acks_lowest_nak != seq + i) {
 745                                 call->acks_lowest_nak = seq + i;
 746                                 summary->new_low_nack = true;
 747                         }
 748                         summary->saw_nacks = true;
 749                 }
 750         }
 751 }
 752
 753 /*
 754  * Return true if the ACK is valid - ie. it doesn't appear to have regressed
 755  * with respect to the ack state conveyed by preceding ACKs.
 756  */
 757 static bool rxrpc_is_ack_valid(struct rxrpc_call *call,
 758                                rxrpc_seq_t first_pkt, rxrpc_seq_t prev_pkt)
 759 {
 760         rxrpc_seq_t base = READ_ONCE(call->acks_first_seq);
 761
 762         if (after(first_pkt, base))
 763                 return true; /* The window advanced */
 764
 765         if (before(first_pkt, base))
 766                 return false; /* firstPacket regressed */
 767
 768         if (after_eq(prev_pkt, call->acks_prev_seq))
 769                 return true; /* previousPacket hasn't regressed. */
 770
 771         /* Some rx implementations put a serial number in previousPacket. */
 772         if (after_eq(prev_pkt, base + call->tx_winsize))
 773                 return false;
 774         return true;
 775 }
 776
 777 /*
 778  * Process an ACK packet.
 779  *
 780  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 781  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 782  *
 783  * A hard-ACK means that a packet has been processed and may be discarded; a
 784  * soft-ACK means that the packet may be discarded and retransmission
 785  * requested.  A phase is complete when all packets are hard-ACK'd.
 786  */
 787 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 788 {
 789         struct rxrpc_ack_summary summary = { 0 };
 790         struct rxrpc_ackpacket ack;
 791         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 792         struct rxrpc_ackinfo info;
 793         rxrpc_serial_t ack_serial, acked_serial;
 794         rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
 795         int nr_acks, offset, ioffset;
 796
 797         _enter("");
 798
 799         offset = sizeof(struct rxrpc_wire_header);
 800         if (skb_copy_bits(skb, offset, &ack, sizeof(ack)) < 0)
 801                 return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack);
 802         offset += sizeof(ack);
 803
 804         ack_serial = sp->hdr.serial;
 805         acked_serial = ntohl(ack.serial);
 806         first_soft_ack = ntohl(ack.firstPacket);
 807         prev_pkt = ntohl(ack.previousPacket);
 808         hard_ack = first_soft_ack - 1;
 809         nr_acks = ack.nAcks;
 810         summary.ack_reason = (ack.reason < RXRPC_ACK__INVALID ?
 811                               ack.reason : RXRPC_ACK__INVALID);
 812
 813         trace_rxrpc_rx_ack(call, ack_serial, acked_serial,
 814                            first_soft_ack, prev_pkt,
 815                            summary.ack_reason, nr_acks);
 816         rxrpc_inc_stat(call->rxnet, stat_rx_acks[ack.reason]);
 817
 818         switch (ack.reason) {
 819         case RXRPC_ACK_PING_RESPONSE:
 820                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 821                                          rxrpc_rtt_rx_ping_response);
 822                 break;
 823         case RXRPC_ACK_REQUESTED:
 824                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 825                                          rxrpc_rtt_rx_requested_ack);
 826                 break;
 827         default:
 828                 if (acked_serial != 0)
 829                         rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 830                                                  rxrpc_rtt_rx_cancel);
 831                 break;
 832         }
 833
 834         if (ack.reason == RXRPC_ACK_PING) {
 835                 rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial,
 836                                rxrpc_propose_ack_respond_to_ping);
 837         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 838                 rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, ack_serial,
 839                                rxrpc_propose_ack_respond_to_ack);
 840         }
 841
 842         /* If we get an EXCEEDS_WINDOW ACK from the server, it probably
 843          * indicates that the client address changed due to NAT.  The server
 844          * lost the call because it switched to a different peer.
 845          */
 846         if (unlikely(ack.reason == RXRPC_ACK_EXCEEDS_WINDOW) &&
 847             first_soft_ack == 1 &&
 848             prev_pkt == 0 &&
 849             rxrpc_is_client_call(call)) {
 850                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 851                                           0, -ENETRESET);
 852                 return;
 853         }
 854
 855         /* If we get an OUT_OF_SEQUENCE ACK from the server, that can also
 856          * indicate a change of address.  However, we can retransmit the call
 857          * if we still have it buffered to the beginning.
 858          */
 859         if (unlikely(ack.reason == RXRPC_ACK_OUT_OF_SEQUENCE) &&
 860             first_soft_ack == 1 &&
 861             prev_pkt == 0 &&
 862             call->acks_hard_ack == 0 &&
 863             rxrpc_is_client_call(call)) {
 864                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 865                                           0, -ENETRESET);
 866                 return;
 867         }
 868
 869         /* Discard any out-of-order or duplicate ACKs (outside lock). */
 870         if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 871                 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 872                                            first_soft_ack, call->acks_first_seq,
 873                                            prev_pkt, call->acks_prev_seq);
 874                 return;
 875         }
 876
 877         info.rxMTU = 0;
 878         ioffset = offset + nr_acks + 3;
 879         if (skb->len >= ioffset + sizeof(info) &&
 880             skb_copy_bits(skb, ioffset, &info, sizeof(info)) < 0)
 881                 return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack_info);
 882
 883         if (nr_acks > 0)
 884                 skb_condense(skb);
 885
 886         call->acks_latest_ts = skb->tstamp;
 887         call->acks_first_seq = first_soft_ack;
 888         call->acks_prev_seq = prev_pkt;
 889
 890         switch (ack.reason) {
 891         case RXRPC_ACK_PING:
 892                 break;
 893         default:
 894                 if (after(acked_serial, call->acks_highest_serial))
 895                         call->acks_highest_serial = acked_serial;
 896                 break;
 897         }
 898
 899         /* Parse rwind and mtu sizes if provided. */
 900         if (info.rxMTU)
 901                 rxrpc_input_ackinfo(call, skb, &info);
 902
 903         if (first_soft_ack == 0)
 904                 return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_zero);
 905
 906         /* Ignore ACKs unless we are or have just been transmitting. */
 907         switch (READ_ONCE(call->state)) {
 908         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 909         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 910         case RXRPC_CALL_SERVER_SEND_REPLY:
 911         case RXRPC_CALL_SERVER_AWAIT_ACK:
 912                 break;
 913         default:
 914                 return;
 915         }
 916
 917         if (before(hard_ack, call->acks_hard_ack) ||
 918             after(hard_ack, call->tx_top))
 919                 return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_outside_window);
 920         if (nr_acks > call->tx_top - hard_ack)
 921                 return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_sack_overflow);
 922
 923         if (after(hard_ack, call->acks_hard_ack)) {
 924                 if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
 925                         rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ack);
 926                         return;
 927                 }
 928         }
 929
 930         if (nr_acks > 0) {
 931                 if (offset > (int)skb->len - nr_acks)
 932                         return rxrpc_proto_abort(call, 0, rxrpc_eproto_ackr_short_sack);
 933                 rxrpc_input_soft_acks(call, skb->data + offset, first_soft_ack,
 934                                       nr_acks, &summary);
 935         }
 936
 937         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) &&
 938             summary.nr_acks == call->tx_top - hard_ack &&
 939             rxrpc_is_client_call(call))
 940                 rxrpc_propose_ping(call, ack_serial,
 941                                    rxrpc_propose_ack_ping_for_lost_reply);
 942
 943         rxrpc_congestion_management(call, skb, &summary, acked_serial);
 944 }
 945
 946 /*
 947  * Process an ACKALL packet.
 948  */
 949 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 950 {
 951         struct rxrpc_ack_summary summary = { 0 };
 952
 953         if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
 954                 rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ackall);
 955 }
 956
 957 /*
 958  * Process an ABORT packet directed at a call.
 959  */
 960 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 961 {
 962         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 963
 964         trace_rxrpc_rx_abort(call, sp->hdr.serial, skb->priority);
 965
 966         rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 967                                   skb->priority, -ECONNABORTED);
 968 }
 969
 970 /*
 971  * Process an incoming call packet.
 972  */
 973 void rxrpc_input_call_packet(struct rxrpc_call *call, struct sk_buff *skb)
 974 {
 975         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 976         unsigned long timo;
 977
 978         _enter("%p,%p", call, skb);
 979
 980         if (sp->hdr.serviceId != call->dest_srx.srx_service)
 981                 call->dest_srx.srx_service = sp->hdr.serviceId;
 982         if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
 983                 call->rx_serial = sp->hdr.serial;
 984         if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
 985                 set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
 986
 987         timo = READ_ONCE(call->next_rx_timo);
 988         if (timo) {
 989                 unsigned long now = jiffies, expect_rx_by;
 990
 991                 expect_rx_by = now + timo;
 992                 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
 993                 rxrpc_reduce_call_timer(call, expect_rx_by, now,
 994                                         rxrpc_timer_set_for_normal);
 995         }
 996
 997         switch (sp->hdr.type) {
 998         case RXRPC_PACKET_TYPE_DATA:
 999                 return rxrpc_input_data(call, skb);
1000
1001         case RXRPC_PACKET_TYPE_ACK:
1002                 return rxrpc_input_ack(call, skb);
1003
1004         case RXRPC_PACKET_TYPE_BUSY:
1005                 /* Just ignore BUSY packets from the server; the retry and
1006                  * lifespan timers will take care of business.  BUSY packets
1007                  * from the client don't make sense.
1008                  */
1009                 return;
1010
1011         case RXRPC_PACKET_TYPE_ABORT:
1012                 return rxrpc_input_abort(call, skb);
1013
1014         case RXRPC_PACKET_TYPE_ACKALL:
1015                 return rxrpc_input_ackall(call, skb);
1016
1017         default:
1018                 break;
1019         }
1020 }
1021
1022 /*
1023  * Handle a new service call on a channel implicitly completing the preceding
1024  * call on that channel.  This does not apply to client conns.
1025  *
1026  * TODO: If callNumber > call_id + 1, renegotiate security.
1027  */
1028 void rxrpc_implicit_end_call(struct rxrpc_call *call, struct sk_buff *skb)
1029 {
1030         switch (READ_ONCE(call->state)) {
1031         case RXRPC_CALL_SERVER_AWAIT_ACK:
1032                 rxrpc_call_completed(call);
1033                 fallthrough;
1034         case RXRPC_CALL_COMPLETE:
1035                 break;
1036         default:
1037                 rxrpc_abort_call(call, 0, RX_CALL_DEAD, -ESHUTDOWN,
1038                                  rxrpc_eproto_improper_term);
1039                 trace_rxrpc_improper_term(call);
1040                 break;
1041         }
1042
1043         rxrpc_input_call_event(call, skb);
1044 }