net/rxrpc/input.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* RxRPC packet reception
   3  *
   4  * Copyright (C) 2007, 2016 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);
  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->tx_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         switch (call->cong_mode) {
  62         case RXRPC_CALL_SLOW_START:
  63                 if (summary->nr_nacks > 0)
  64                         goto packet_loss_detected;
  65                 if (summary->cumulative_acks > 0)
  66                         cwnd += 1;
  67                 if (cwnd >= call->cong_ssthresh) {
  68                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  69                         call->cong_tstamp = skb->tstamp;
  70                 }
  71                 goto out;
  72
  73         case RXRPC_CALL_CONGEST_AVOIDANCE:
  74                 if (summary->nr_nacks > 0)
  75                         goto packet_loss_detected;
  76
  77                 /* We analyse the number of packets that get ACK'd per RTT
  78                  * period and increase the window if we managed to fill it.
  79                  */
  80                 if (call->peer->rtt_count == 0)
  81                         goto out;
  82                 if (ktime_before(skb->tstamp,
  83                                  ktime_add_us(call->cong_tstamp,
  84                                               call->peer->srtt_us >> 3)))
  85                         goto out_no_clear_ca;
  86                 change = rxrpc_cong_rtt_window_end;
  87                 call->cong_tstamp = skb->tstamp;
  88                 if (cumulative_acks >= cwnd)
  89                         cwnd++;
  90                 goto out;
  91
  92         case RXRPC_CALL_PACKET_LOSS:
  93                 if (summary->nr_nacks == 0)
  94                         goto resume_normality;
  95
  96                 if (summary->new_low_nack) {
  97                         change = rxrpc_cong_new_low_nack;
  98                         call->cong_dup_acks = 1;
  99                         if (call->cong_extra > 1)
 100                                 call->cong_extra = 1;
 101                         goto send_extra_data;
 102                 }
 103
 104                 call->cong_dup_acks++;
 105                 if (call->cong_dup_acks < 3)
 106                         goto send_extra_data;
 107
 108                 change = rxrpc_cong_begin_retransmission;
 109                 call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
 110                 call->cong_ssthresh = max_t(unsigned int,
 111                                             summary->flight_size / 2, 2);
 112                 cwnd = call->cong_ssthresh + 3;
 113                 call->cong_extra = 0;
 114                 call->cong_dup_acks = 0;
 115                 resend = true;
 116                 goto out;
 117
 118         case RXRPC_CALL_FAST_RETRANSMIT:
 119                 if (!summary->new_low_nack) {
 120                         if (summary->nr_new_acks == 0)
 121                                 cwnd += 1;
 122                         call->cong_dup_acks++;
 123                         if (call->cong_dup_acks == 2) {
 124                                 change = rxrpc_cong_retransmit_again;
 125                                 call->cong_dup_acks = 0;
 126                                 resend = true;
 127                         }
 128                 } else {
 129                         change = rxrpc_cong_progress;
 130                         cwnd = call->cong_ssthresh;
 131                         if (summary->nr_nacks == 0)
 132                                 goto resume_normality;
 133                 }
 134                 goto out;
 135
 136         default:
 137                 BUG();
 138                 goto out;
 139         }
 140
 141 resume_normality:
 142         change = rxrpc_cong_cleared_nacks;
 143         call->cong_dup_acks = 0;
 144         call->cong_extra = 0;
 145         call->cong_tstamp = skb->tstamp;
 146         if (cwnd < call->cong_ssthresh)
 147                 call->cong_mode = RXRPC_CALL_SLOW_START;
 148         else
 149                 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
 150 out:
 151         cumulative_acks = 0;
 152 out_no_clear_ca:
 153         if (cwnd >= RXRPC_RXTX_BUFF_SIZE - 1)
 154                 cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
 155         call->cong_cwnd = cwnd;
 156         call->cong_cumul_acks = cumulative_acks;
 157         trace_rxrpc_congest(call, summary, acked_serial, change);
 158         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 159                 rxrpc_queue_call(call);
 160         return;
 161
 162 packet_loss_detected:
 163         change = rxrpc_cong_saw_nack;
 164         call->cong_mode = RXRPC_CALL_PACKET_LOSS;
 165         call->cong_dup_acks = 0;
 166         goto send_extra_data;
 167
 168 send_extra_data:
 169         /* Send some previously unsent DATA if we have some to advance the ACK
 170          * state.
 171          */
 172         if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
 173             RXRPC_TX_ANNO_LAST ||
 174             summary->nr_acks != call->tx_top - call->tx_hard_ack) {
 175                 call->cong_extra++;
 176                 wake_up(&call->waitq);
 177         }
 178         goto out_no_clear_ca;
 179 }
 180
 181 /*
 182  * Apply a hard ACK by advancing the Tx window.
 183  */
 184 static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 185                                    struct rxrpc_ack_summary *summary)
 186 {
 187         struct sk_buff *skb, *list = NULL;
 188         bool rot_last = false;
 189         int ix;
 190         u8 annotation;
 191
 192         if (call->acks_lowest_nak == call->tx_hard_ack) {
 193                 call->acks_lowest_nak = to;
 194         } else if (before_eq(call->acks_lowest_nak, to)) {
 195                 summary->new_low_nack = true;
 196                 call->acks_lowest_nak = to;
 197         }
 198
 199         spin_lock(&call->lock);
 200
 201         while (before(call->tx_hard_ack, to)) {
 202                 call->tx_hard_ack++;
 203                 ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
 204                 skb = call->rxtx_buffer[ix];
 205                 annotation = call->rxtx_annotations[ix];
 206                 rxrpc_see_skb(skb, rxrpc_skb_rotated);
 207                 call->rxtx_buffer[ix] = NULL;
 208                 call->rxtx_annotations[ix] = 0;
 209                 skb->next = list;
 210                 list = skb;
 211
 212                 if (annotation & RXRPC_TX_ANNO_LAST) {
 213                         set_bit(RXRPC_CALL_TX_LAST, &call->flags);
 214                         rot_last = true;
 215                 }
 216                 if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK)
 217                         summary->nr_rot_new_acks++;
 218         }
 219
 220         spin_unlock(&call->lock);
 221
 222         trace_rxrpc_transmit(call, (rot_last ?
 223                                     rxrpc_transmit_rotate_last :
 224                                     rxrpc_transmit_rotate));
 225         wake_up(&call->waitq);
 226
 227         while (list) {
 228                 skb = list;
 229                 list = skb->next;
 230                 skb_mark_not_on_list(skb);
 231                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 232         }
 233
 234         return rot_last;
 235 }
 236
 237 /*
 238  * End the transmission phase of a call.
 239  *
 240  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 241  * or a final ACK packet.
 242  */
 243 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 244                                const char *abort_why)
 245 {
 246         unsigned int state;
 247
 248         ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 249
 250         write_lock(&call->state_lock);
 251
 252         state = call->state;
 253         switch (state) {
 254         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 255         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 256                 if (reply_begun)
 257                         call->state = state = RXRPC_CALL_CLIENT_RECV_REPLY;
 258                 else
 259                         call->state = state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 260                 break;
 261
 262         case RXRPC_CALL_SERVER_AWAIT_ACK:
 263                 __rxrpc_call_completed(call);
 264                 state = call->state;
 265                 break;
 266
 267         default:
 268                 goto bad_state;
 269         }
 270
 271         write_unlock(&call->state_lock);
 272         if (state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 273                 trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
 274         else
 275                 trace_rxrpc_transmit(call, rxrpc_transmit_end);
 276         _leave(" = ok");
 277         return true;
 278
 279 bad_state:
 280         write_unlock(&call->state_lock);
 281         kdebug("end_tx %s", rxrpc_call_states[call->state]);
 282         rxrpc_proto_abort(abort_why, call, call->tx_top);
 283         return false;
 284 }
 285
 286 /*
 287  * Begin the reply reception phase of a call.
 288  */
 289 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 290 {
 291         struct rxrpc_ack_summary summary = { 0 };
 292         unsigned long now, timo;
 293         rxrpc_seq_t top = READ_ONCE(call->tx_top);
 294
 295         if (call->ackr_reason) {
 296                 spin_lock_bh(&call->lock);
 297                 call->ackr_reason = 0;
 298                 spin_unlock_bh(&call->lock);
 299                 now = jiffies;
 300                 timo = now + MAX_JIFFY_OFFSET;
 301                 WRITE_ONCE(call->resend_at, timo);
 302                 WRITE_ONCE(call->ack_at, timo);
 303                 trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
 304         }
 305
 306         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 307                 if (!rxrpc_rotate_tx_window(call, top, &summary)) {
 308                         rxrpc_proto_abort("TXL", call, top);
 309                         return false;
 310                 }
 311         }
 312         return rxrpc_end_tx_phase(call, true, "ETD");
 313 }
 314
 315 /*
 316  * Scan a data packet to validate its structure and to work out how many
 317  * subpackets it contains.
 318  *
 319  * A jumbo packet is a collection of consecutive packets glued together with
 320  * little headers between that indicate how to change the initial header for
 321  * each subpacket.
 322  *
 323  * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 324  * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 325  * size.
 326  */
 327 static bool rxrpc_validate_data(struct sk_buff *skb)
 328 {
 329         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 330         unsigned int offset = sizeof(struct rxrpc_wire_header);
 331         unsigned int len = skb->len;
 332         u8 flags = sp->hdr.flags;
 333
 334         for (;;) {
 335                 if (flags & RXRPC_REQUEST_ACK)
 336                         __set_bit(sp->nr_subpackets, sp->rx_req_ack);
 337                 sp->nr_subpackets++;
 338
 339                 if (!(flags & RXRPC_JUMBO_PACKET))
 340                         break;
 341
 342                 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 343                         goto protocol_error;
 344                 if (flags & RXRPC_LAST_PACKET)
 345                         goto protocol_error;
 346                 offset += RXRPC_JUMBO_DATALEN;
 347                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 348                         goto protocol_error;
 349                 offset += sizeof(struct rxrpc_jumbo_header);
 350         }
 351
 352         if (flags & RXRPC_LAST_PACKET)
 353                 sp->rx_flags |= RXRPC_SKB_INCL_LAST;
 354         return true;
 355
 356 protocol_error:
 357         return false;
 358 }
 359
 360 /*
 361  * Handle reception of a duplicate packet.
 362  *
 363  * We have to take care to avoid an attack here whereby we're given a series of
 364  * jumbograms, each with a sequence number one before the preceding one and
 365  * filled up to maximum UDP size.  If they never send us the first packet in
 366  * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 367  * space until the call times out.
 368  *
 369  * We limit the space usage by only accepting three duplicate jumbo packets per
 370  * call.  After that, we tell the other side we're no longer accepting jumbos
 371  * (that information is encoded in the ACK packet).
 372  */
 373 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 374                                  bool is_jumbo, bool *_jumbo_bad)
 375 {
 376         /* Discard normal packets that are duplicates. */
 377         if (is_jumbo)
 378                 return;
 379
 380         /* Skip jumbo subpackets that are duplicates.  When we've had three or
 381          * more partially duplicate jumbo packets, we refuse to take any more
 382          * jumbos for this call.
 383          */
 384         if (!*_jumbo_bad) {
 385                 call->nr_jumbo_bad++;
 386                 *_jumbo_bad = true;
 387         }
 388 }
 389
 390 /*
 391  * Process a DATA packet, adding the packet to the Rx ring.  The caller's
 392  * packet ref must be passed on or discarded.
 393  */
 394 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 395 {
 396         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 397         enum rxrpc_call_state state;
 398         unsigned int j, nr_subpackets, nr_unacked = 0;
 399         rxrpc_serial_t serial = sp->hdr.serial, ack_serial = serial;
 400         rxrpc_seq_t seq0 = sp->hdr.seq, hard_ack;
 401         bool jumbo_bad = false;
 402
 403         _enter("{%u,%u},{%u,%u}",
 404                call->rx_hard_ack, call->rx_top, skb->len, seq0);
 405
 406         _proto("Rx DATA %%%u { #%u f=%02x n=%u }",
 407                sp->hdr.serial, seq0, sp->hdr.flags, sp->nr_subpackets);
 408
 409         state = READ_ONCE(call->state);
 410         if (state >= RXRPC_CALL_COMPLETE) {
 411                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 412                 return;
 413         }
 414
 415         if (state == RXRPC_CALL_SERVER_RECV_REQUEST) {
 416                 unsigned long timo = READ_ONCE(call->next_req_timo);
 417                 unsigned long now, expect_req_by;
 418
 419                 if (timo) {
 420                         now = jiffies;
 421                         expect_req_by = now + timo;
 422                         WRITE_ONCE(call->expect_req_by, expect_req_by);
 423                         rxrpc_reduce_call_timer(call, expect_req_by, now,
 424                                                 rxrpc_timer_set_for_idle);
 425                 }
 426         }
 427
 428         rxrpc_inc_stat(call->rxnet, stat_rx_data);
 429         if (sp->hdr.flags & RXRPC_REQUEST_ACK)
 430                 rxrpc_inc_stat(call->rxnet, stat_rx_data_reqack);
 431         if (sp->hdr.flags & RXRPC_JUMBO_PACKET)
 432                 rxrpc_inc_stat(call->rxnet, stat_rx_data_jumbo);
 433
 434         spin_lock(&call->input_lock);
 435
 436         /* Received data implicitly ACKs all of the request packets we sent
 437          * when we're acting as a client.
 438          */
 439         if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 440              state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 441             !rxrpc_receiving_reply(call))
 442                 goto unlock;
 443
 444         hard_ack = READ_ONCE(call->rx_hard_ack);
 445
 446         nr_subpackets = sp->nr_subpackets;
 447         if (nr_subpackets > 1) {
 448                 if (call->nr_jumbo_bad > 3) {
 449                         rxrpc_send_ACK(call, RXRPC_ACK_NOSPACE, serial,
 450                                        rxrpc_propose_ack_input_data);
 451                         goto unlock;
 452                 }
 453         }
 454
 455         for (j = 0; j < nr_subpackets; j++) {
 456                 rxrpc_serial_t serial = sp->hdr.serial + j;
 457                 rxrpc_seq_t seq = seq0 + j;
 458                 unsigned int ix = seq & RXRPC_RXTX_BUFF_MASK;
 459                 bool terminal = (j == nr_subpackets - 1);
 460                 bool last = terminal && (sp->rx_flags & RXRPC_SKB_INCL_LAST);
 461                 bool acked = false;
 462                 u8 flags, annotation = j;
 463
 464                 _proto("Rx DATA+%u %%%u { #%x t=%u l=%u }",
 465                      j, serial, seq, terminal, last);
 466
 467                 if (last) {
 468                         if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 469                             seq != call->rx_top) {
 470                                 rxrpc_proto_abort("LSN", call, seq);
 471                                 goto unlock;
 472                         }
 473                 } else {
 474                         if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 475                             after_eq(seq, call->rx_top)) {
 476                                 rxrpc_proto_abort("LSA", call, seq);
 477                                 goto unlock;
 478                         }
 479                 }
 480
 481                 flags = 0;
 482                 if (last)
 483                         flags |= RXRPC_LAST_PACKET;
 484                 if (!terminal)
 485                         flags |= RXRPC_JUMBO_PACKET;
 486                 if (test_bit(j, sp->rx_req_ack))
 487                         flags |= RXRPC_REQUEST_ACK;
 488                 trace_rxrpc_rx_data(call->debug_id, seq, serial, flags, annotation);
 489
 490                 if (before_eq(seq, hard_ack)) {
 491                         rxrpc_send_ACK(call, RXRPC_ACK_DUPLICATE, serial,
 492                                        rxrpc_propose_ack_input_data);
 493                         continue;
 494                 }
 495
 496                 if (call->rxtx_buffer[ix]) {
 497                         rxrpc_input_dup_data(call, seq, nr_subpackets > 1,
 498                                              &jumbo_bad);
 499                         rxrpc_send_ACK(call, RXRPC_ACK_DUPLICATE, serial,
 500                                        rxrpc_propose_ack_input_data);
 501                         continue;
 502                 }
 503
 504                 if (after(seq, hard_ack + call->rx_winsize)) {
 505                         rxrpc_send_ACK(call, RXRPC_ACK_EXCEEDS_WINDOW, serial,
 506                                        rxrpc_propose_ack_input_data);
 507                         if (flags & RXRPC_JUMBO_PACKET) {
 508                                 if (!jumbo_bad) {
 509                                         call->nr_jumbo_bad++;
 510                                         jumbo_bad = true;
 511                                 }
 512                         }
 513
 514                         goto unlock;
 515                 }
 516
 517                 if (flags & RXRPC_REQUEST_ACK) {
 518                         rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, serial,
 519                                        rxrpc_propose_ack_input_data);
 520                         acked = true;
 521                 }
 522
 523                 if (after(seq0, call->ackr_highest_seq))
 524                         call->ackr_highest_seq = seq0;
 525
 526                 /* Queue the packet.  We use a couple of memory barriers here as need
 527                  * to make sure that rx_top is perceived to be set after the buffer
 528                  * pointer and that the buffer pointer is set after the annotation and
 529                  * the skb data.
 530                  *
 531                  * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 532                  * and also rxrpc_fill_out_ack().
 533                  */
 534                 if (!terminal)
 535                         rxrpc_get_skb(skb, rxrpc_skb_got);
 536                 call->rxtx_annotations[ix] = annotation;
 537                 smp_wmb();
 538                 call->rxtx_buffer[ix] = skb;
 539                 if (after(seq, call->rx_top)) {
 540                         smp_store_release(&call->rx_top, seq);
 541                 } else if (before(seq, call->rx_top)) {
 542                         /* Send an immediate ACK if we fill in a hole */
 543                         if (!acked) {
 544                                 rxrpc_send_ACK(call, RXRPC_ACK_DELAY, serial,
 545                                                rxrpc_propose_ack_input_data);
 546                                 acked = true;
 547                         }
 548                 }
 549
 550                 if (terminal) {
 551                         /* From this point on, we're not allowed to touch the
 552                          * packet any longer as its ref now belongs to the Rx
 553                          * ring.
 554                          */
 555                         skb = NULL;
 556                         sp = NULL;
 557                 }
 558
 559                 if (last) {
 560                         set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 561                         trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 562                 } else {
 563                         trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 564                 }
 565
 566                 if (after_eq(seq, call->rx_expect_next)) {
 567                         if (after(seq, call->rx_expect_next)) {
 568                                 _net("OOS %u > %u", seq, call->rx_expect_next);
 569                                 rxrpc_send_ACK(call, RXRPC_ACK_OUT_OF_SEQUENCE, serial,
 570                                                rxrpc_propose_ack_input_data);
 571                                 acked = true;
 572                         }
 573                         call->rx_expect_next = seq + 1;
 574                 }
 575
 576                 if (!acked) {
 577                         nr_unacked++;
 578                         ack_serial = serial;
 579                 }
 580         }
 581
 582 unlock:
 583         if (atomic_add_return(nr_unacked, &call->ackr_nr_unacked) > 2)
 584                 rxrpc_send_ACK(call, RXRPC_ACK_IDLE, ack_serial,
 585                                rxrpc_propose_ack_input_data);
 586         else
 587                 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, ack_serial,
 588                                   rxrpc_propose_ack_input_data);
 589
 590         trace_rxrpc_notify_socket(call->debug_id, serial);
 591         rxrpc_notify_socket(call);
 592
 593         spin_unlock(&call->input_lock);
 594         rxrpc_free_skb(skb, rxrpc_skb_freed);
 595         _leave(" [queued]");
 596 }
 597
 598 /*
 599  * See if there's a cached RTT probe to complete.
 600  */
 601 static void rxrpc_complete_rtt_probe(struct rxrpc_call *call,
 602                                      ktime_t resp_time,
 603                                      rxrpc_serial_t acked_serial,
 604                                      rxrpc_serial_t ack_serial,
 605                                      enum rxrpc_rtt_rx_trace type)
 606 {
 607         rxrpc_serial_t orig_serial;
 608         unsigned long avail;
 609         ktime_t sent_at;
 610         bool matched = false;
 611         int i;
 612
 613         avail = READ_ONCE(call->rtt_avail);
 614         smp_rmb(); /* Read avail bits before accessing data. */
 615
 616         for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) {
 617                 if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail))
 618                         continue;
 619
 620                 sent_at = call->rtt_sent_at[i];
 621                 orig_serial = call->rtt_serial[i];
 622
 623                 if (orig_serial == acked_serial) {
 624                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 625                         smp_mb(); /* Read data before setting avail bit */
 626                         set_bit(i, &call->rtt_avail);
 627                         if (type != rxrpc_rtt_rx_cancel)
 628                                 rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial,
 629                                                    sent_at, resp_time);
 630                         else
 631                                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_cancel, i,
 632                                                    orig_serial, acked_serial, 0, 0);
 633                         matched = true;
 634                 }
 635
 636                 /* If a later serial is being acked, then mark this slot as
 637                  * being available.
 638                  */
 639                 if (after(acked_serial, orig_serial)) {
 640                         trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i,
 641                                            orig_serial, acked_serial, 0, 0);
 642                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 643                         smp_wmb();
 644                         set_bit(i, &call->rtt_avail);
 645                 }
 646         }
 647
 648         if (!matched)
 649                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0);
 650 }
 651
 652 /*
 653  * Process the response to a ping that we sent to find out if we lost an ACK.
 654  *
 655  * If we got back a ping response that indicates a lower tx_top than what we
 656  * had at the time of the ping transmission, we adjudge all the DATA packets
 657  * sent between the response tx_top and the ping-time tx_top to have been lost.
 658  */
 659 static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
 660 {
 661         rxrpc_seq_t top, bottom, seq;
 662         bool resend = false;
 663
 664         spin_lock_bh(&call->lock);
 665
 666         bottom = call->tx_hard_ack + 1;
 667         top = call->acks_lost_top;
 668         if (before(bottom, top)) {
 669                 for (seq = bottom; before_eq(seq, top); seq++) {
 670                         int ix = seq & RXRPC_RXTX_BUFF_MASK;
 671                         u8 annotation = call->rxtx_annotations[ix];
 672                         u8 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 673
 674                         if (anno_type != RXRPC_TX_ANNO_UNACK)
 675                                 continue;
 676                         annotation &= ~RXRPC_TX_ANNO_MASK;
 677                         annotation |= RXRPC_TX_ANNO_RETRANS;
 678                         call->rxtx_annotations[ix] = annotation;
 679                         resend = true;
 680                 }
 681         }
 682
 683         spin_unlock_bh(&call->lock);
 684
 685         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 686                 rxrpc_queue_call(call);
 687 }
 688
 689 /*
 690  * Process a ping response.
 691  */
 692 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 693                                       ktime_t resp_time,
 694                                       rxrpc_serial_t acked_serial,
 695                                       rxrpc_serial_t ack_serial)
 696 {
 697         if (acked_serial == call->acks_lost_ping)
 698                 rxrpc_input_check_for_lost_ack(call);
 699 }
 700
 701 /*
 702  * Process the extra information that may be appended to an ACK packet
 703  */
 704 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 705                                 struct rxrpc_ackinfo *ackinfo)
 706 {
 707         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 708         struct rxrpc_peer *peer;
 709         unsigned int mtu;
 710         bool wake = false;
 711         u32 rwind = ntohl(ackinfo->rwind);
 712
 713         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 714                sp->hdr.serial,
 715                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 716                rwind, ntohl(ackinfo->jumbo_max));
 717
 718         if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 719                 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 720         if (call->tx_winsize != rwind) {
 721                 if (rwind > call->tx_winsize)
 722                         wake = true;
 723                 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake);
 724                 call->tx_winsize = rwind;
 725         }
 726
 727         if (call->cong_ssthresh > rwind)
 728                 call->cong_ssthresh = rwind;
 729
 730         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 731
 732         peer = call->peer;
 733         if (mtu < peer->maxdata) {
 734                 spin_lock_bh(&peer->lock);
 735                 peer->maxdata = mtu;
 736                 peer->mtu = mtu + peer->hdrsize;
 737                 spin_unlock_bh(&peer->lock);
 738                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 739         }
 740
 741         if (wake)
 742                 wake_up(&call->waitq);
 743 }
 744
 745 /*
 746  * Process individual soft ACKs.
 747  *
 748  * Each ACK in the array corresponds to one packet and can be either an ACK or
 749  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 750  * packets that lie beyond the end of the ACK list are scheduled for resend by
 751  * the timer on the basis that the peer might just not have processed them at
 752  * the time the ACK was sent.
 753  */
 754 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 755                                   rxrpc_seq_t seq, int nr_acks,
 756                                   struct rxrpc_ack_summary *summary)
 757 {
 758         int ix;
 759         u8 annotation, anno_type;
 760
 761         for (; nr_acks > 0; nr_acks--, seq++) {
 762                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 763                 annotation = call->rxtx_annotations[ix];
 764                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 765                 annotation &= ~RXRPC_TX_ANNO_MASK;
 766                 switch (*acks++) {
 767                 case RXRPC_ACK_TYPE_ACK:
 768                         summary->nr_acks++;
 769                         if (anno_type == RXRPC_TX_ANNO_ACK)
 770                                 continue;
 771                         summary->nr_new_acks++;
 772                         call->rxtx_annotations[ix] =
 773                                 RXRPC_TX_ANNO_ACK | annotation;
 774                         break;
 775                 case RXRPC_ACK_TYPE_NACK:
 776                         if (!summary->nr_nacks &&
 777                             call->acks_lowest_nak != seq) {
 778                                 call->acks_lowest_nak = seq;
 779                                 summary->new_low_nack = true;
 780                         }
 781                         summary->nr_nacks++;
 782                         if (anno_type == RXRPC_TX_ANNO_NAK)
 783                                 continue;
 784                         summary->nr_new_nacks++;
 785                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
 786                                 continue;
 787                         call->rxtx_annotations[ix] =
 788                                 RXRPC_TX_ANNO_NAK | annotation;
 789                         break;
 790                 default:
 791                         return rxrpc_proto_abort("SFT", call, 0);
 792                 }
 793         }
 794 }
 795
 796 /*
 797  * Return true if the ACK is valid - ie. it doesn't appear to have regressed
 798  * with respect to the ack state conveyed by preceding ACKs.
 799  */
 800 static bool rxrpc_is_ack_valid(struct rxrpc_call *call,
 801                                rxrpc_seq_t first_pkt, rxrpc_seq_t prev_pkt)
 802 {
 803         rxrpc_seq_t base = READ_ONCE(call->acks_first_seq);
 804
 805         if (after(first_pkt, base))
 806                 return true; /* The window advanced */
 807
 808         if (before(first_pkt, base))
 809                 return false; /* firstPacket regressed */
 810
 811         if (after_eq(prev_pkt, call->acks_prev_seq))
 812                 return true; /* previousPacket hasn't regressed. */
 813
 814         /* Some rx implementations put a serial number in previousPacket. */
 815         if (after_eq(prev_pkt, base + call->tx_winsize))
 816                 return false;
 817         return true;
 818 }
 819
 820 /*
 821  * Process an ACK packet.
 822  *
 823  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 824  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 825  *
 826  * A hard-ACK means that a packet has been processed and may be discarded; a
 827  * soft-ACK means that the packet may be discarded and retransmission
 828  * requested.  A phase is complete when all packets are hard-ACK'd.
 829  */
 830 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 831 {
 832         struct rxrpc_ack_summary summary = { 0 };
 833         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 834         union {
 835                 struct rxrpc_ackpacket ack;
 836                 struct rxrpc_ackinfo info;
 837                 u8 acks[RXRPC_MAXACKS];
 838         } buf;
 839         rxrpc_serial_t ack_serial, acked_serial;
 840         rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
 841         int nr_acks, offset, ioffset;
 842
 843         _enter("");
 844
 845         offset = sizeof(struct rxrpc_wire_header);
 846         if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
 847                 _debug("extraction failure");
 848                 return rxrpc_proto_abort("XAK", call, 0);
 849         }
 850         offset += sizeof(buf.ack);
 851
 852         ack_serial = sp->hdr.serial;
 853         acked_serial = ntohl(buf.ack.serial);
 854         first_soft_ack = ntohl(buf.ack.firstPacket);
 855         prev_pkt = ntohl(buf.ack.previousPacket);
 856         hard_ack = first_soft_ack - 1;
 857         nr_acks = buf.ack.nAcks;
 858         summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 859                               buf.ack.reason : RXRPC_ACK__INVALID);
 860
 861         trace_rxrpc_rx_ack(call, ack_serial, acked_serial,
 862                            first_soft_ack, prev_pkt,
 863                            summary.ack_reason, nr_acks);
 864         rxrpc_inc_stat(call->rxnet, stat_rx_acks[buf.ack.reason]);
 865
 866         switch (buf.ack.reason) {
 867         case RXRPC_ACK_PING_RESPONSE:
 868                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 869                                           ack_serial);
 870                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 871                                          rxrpc_rtt_rx_ping_response);
 872                 break;
 873         case RXRPC_ACK_REQUESTED:
 874                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 875                                          rxrpc_rtt_rx_requested_ack);
 876                 break;
 877         default:
 878                 if (acked_serial != 0)
 879                         rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 880                                                  rxrpc_rtt_rx_cancel);
 881                 break;
 882         }
 883
 884         if (buf.ack.reason == RXRPC_ACK_PING) {
 885                 _proto("Rx ACK %%%u PING Request", ack_serial);
 886                 rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial,
 887                                rxrpc_propose_ack_respond_to_ping);
 888         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 889                 rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, ack_serial,
 890                                rxrpc_propose_ack_respond_to_ack);
 891         }
 892
 893         /* If we get an EXCEEDS_WINDOW ACK from the server, it probably
 894          * indicates that the client address changed due to NAT.  The server
 895          * lost the call because it switched to a different peer.
 896          */
 897         if (unlikely(buf.ack.reason == RXRPC_ACK_EXCEEDS_WINDOW) &&
 898             first_soft_ack == 1 &&
 899             prev_pkt == 0 &&
 900             rxrpc_is_client_call(call)) {
 901                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 902                                           0, -ENETRESET);
 903                 return;
 904         }
 905
 906         /* If we get an OUT_OF_SEQUENCE ACK from the server, that can also
 907          * indicate a change of address.  However, we can retransmit the call
 908          * if we still have it buffered to the beginning.
 909          */
 910         if (unlikely(buf.ack.reason == RXRPC_ACK_OUT_OF_SEQUENCE) &&
 911             first_soft_ack == 1 &&
 912             prev_pkt == 0 &&
 913             call->tx_hard_ack == 0 &&
 914             rxrpc_is_client_call(call)) {
 915                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 916                                           0, -ENETRESET);
 917                 return;
 918         }
 919
 920         /* Discard any out-of-order or duplicate ACKs (outside lock). */
 921         if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 922                 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 923                                            first_soft_ack, call->acks_first_seq,
 924                                            prev_pkt, call->acks_prev_seq);
 925                 return;
 926         }
 927
 928         buf.info.rxMTU = 0;
 929         ioffset = offset + nr_acks + 3;
 930         if (skb->len >= ioffset + sizeof(buf.info) &&
 931             skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
 932                 return rxrpc_proto_abort("XAI", call, 0);
 933
 934         spin_lock(&call->input_lock);
 935
 936         /* Discard any out-of-order or duplicate ACKs (inside lock). */
 937         if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 938                 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 939                                            first_soft_ack, call->acks_first_seq,
 940                                            prev_pkt, call->acks_prev_seq);
 941                 goto out;
 942         }
 943         call->acks_latest_ts = skb->tstamp;
 944
 945         call->acks_first_seq = first_soft_ack;
 946         call->acks_prev_seq = prev_pkt;
 947
 948         if (buf.ack.reason != RXRPC_ACK_PING &&
 949             after(acked_serial, call->acks_highest_serial))
 950                 call->acks_highest_serial = acked_serial;
 951
 952         /* Parse rwind and mtu sizes if provided. */
 953         if (buf.info.rxMTU)
 954                 rxrpc_input_ackinfo(call, skb, &buf.info);
 955
 956         if (first_soft_ack == 0) {
 957                 rxrpc_proto_abort("AK0", call, 0);
 958                 goto out;
 959         }
 960
 961         /* Ignore ACKs unless we are or have just been transmitting. */
 962         switch (READ_ONCE(call->state)) {
 963         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 964         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 965         case RXRPC_CALL_SERVER_SEND_REPLY:
 966         case RXRPC_CALL_SERVER_AWAIT_ACK:
 967                 break;
 968         default:
 969                 goto out;
 970         }
 971
 972         if (before(hard_ack, call->tx_hard_ack) ||
 973             after(hard_ack, call->tx_top)) {
 974                 rxrpc_proto_abort("AKW", call, 0);
 975                 goto out;
 976         }
 977         if (nr_acks > call->tx_top - hard_ack) {
 978                 rxrpc_proto_abort("AKN", call, 0);
 979                 goto out;
 980         }
 981
 982         if (after(hard_ack, call->tx_hard_ack)) {
 983                 if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
 984                         rxrpc_end_tx_phase(call, false, "ETA");
 985                         goto out;
 986                 }
 987         }
 988
 989         if (nr_acks > 0) {
 990                 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0) {
 991                         rxrpc_proto_abort("XSA", call, 0);
 992                         goto out;
 993                 }
 994                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
 995                                       &summary);
 996         }
 997
 998         if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
 999             RXRPC_TX_ANNO_LAST &&
1000             summary.nr_acks == call->tx_top - hard_ack &&
1001             rxrpc_is_client_call(call))
1002                 rxrpc_propose_ping(call, ack_serial,
1003                                    rxrpc_propose_ack_ping_for_lost_reply);
1004
1005         rxrpc_congestion_management(call, skb, &summary, acked_serial);
1006 out:
1007         spin_unlock(&call->input_lock);
1008 }
1009
1010 /*
1011  * Process an ACKALL packet.
1012  */
1013 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
1014 {
1015         struct rxrpc_ack_summary summary = { 0 };
1016         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1017
1018         _proto("Rx ACKALL %%%u", sp->hdr.serial);
1019
1020         spin_lock(&call->input_lock);
1021
1022         if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
1023                 rxrpc_end_tx_phase(call, false, "ETL");
1024
1025         spin_unlock(&call->input_lock);
1026 }
1027
1028 /*
1029  * Process an ABORT packet directed at a call.
1030  */
1031 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
1032 {
1033         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1034         __be32 wtmp;
1035         u32 abort_code = RX_CALL_DEAD;
1036
1037         _enter("");
1038
1039         if (skb->len >= 4 &&
1040             skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1041                           &wtmp, sizeof(wtmp)) >= 0)
1042                 abort_code = ntohl(wtmp);
1043
1044         trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
1045
1046         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
1047
1048         rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
1049                                   abort_code, -ECONNABORTED);
1050 }
1051
1052 /*
1053  * Process an incoming call packet.
1054  */
1055 static void rxrpc_input_call_packet(struct rxrpc_call *call,
1056                                     struct sk_buff *skb)
1057 {
1058         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1059         unsigned long timo;
1060
1061         _enter("%p,%p", call, skb);
1062
1063         timo = READ_ONCE(call->next_rx_timo);
1064         if (timo) {
1065                 unsigned long now = jiffies, expect_rx_by;
1066
1067                 expect_rx_by = now + timo;
1068                 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
1069                 rxrpc_reduce_call_timer(call, expect_rx_by, now,
1070                                         rxrpc_timer_set_for_normal);
1071         }
1072
1073         switch (sp->hdr.type) {
1074         case RXRPC_PACKET_TYPE_DATA:
1075                 rxrpc_input_data(call, skb);
1076                 goto no_free;
1077
1078         case RXRPC_PACKET_TYPE_ACK:
1079                 rxrpc_input_ack(call, skb);
1080                 break;
1081
1082         case RXRPC_PACKET_TYPE_BUSY:
1083                 _proto("Rx BUSY %%%u", sp->hdr.serial);
1084
1085                 /* Just ignore BUSY packets from the server; the retry and
1086                  * lifespan timers will take care of business.  BUSY packets
1087                  * from the client don't make sense.
1088                  */
1089                 break;
1090
1091         case RXRPC_PACKET_TYPE_ABORT:
1092                 rxrpc_input_abort(call, skb);
1093                 break;
1094
1095         case RXRPC_PACKET_TYPE_ACKALL:
1096                 rxrpc_input_ackall(call, skb);
1097                 break;
1098
1099         default:
1100                 break;
1101         }
1102
1103         rxrpc_free_skb(skb, rxrpc_skb_freed);
1104 no_free:
1105         _leave("");
1106 }
1107
1108 /*
1109  * Handle a new service call on a channel implicitly completing the preceding
1110  * call on that channel.  This does not apply to client conns.
1111  *
1112  * TODO: If callNumber > call_id + 1, renegotiate security.
1113  */
1114 static void rxrpc_input_implicit_end_call(struct rxrpc_sock *rx,
1115                                           struct rxrpc_connection *conn,
1116                                           struct rxrpc_call *call)
1117 {
1118         switch (READ_ONCE(call->state)) {
1119         case RXRPC_CALL_SERVER_AWAIT_ACK:
1120                 rxrpc_call_completed(call);
1121                 fallthrough;
1122         case RXRPC_CALL_COMPLETE:
1123                 break;
1124         default:
1125                 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
1126                         set_bit(RXRPC_CALL_EV_ABORT, &call->events);
1127                         rxrpc_queue_call(call);
1128                 }
1129                 trace_rxrpc_improper_term(call);
1130                 break;
1131         }
1132
1133         spin_lock(&rx->incoming_lock);
1134         __rxrpc_disconnect_call(conn, call);
1135         spin_unlock(&rx->incoming_lock);
1136 }
1137
1138 /*
1139  * post connection-level events to the connection
1140  * - this includes challenges, responses, some aborts and call terminal packet
1141  *   retransmission.
1142  */
1143 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
1144                                       struct sk_buff *skb)
1145 {
1146         _enter("%p,%p", conn, skb);
1147
1148         skb_queue_tail(&conn->rx_queue, skb);
1149         rxrpc_queue_conn(conn);
1150 }
1151
1152 /*
1153  * post endpoint-level events to the local endpoint
1154  * - this includes debug and version messages
1155  */
1156 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
1157                                        struct sk_buff *skb)
1158 {
1159         _enter("%p,%p", local, skb);
1160
1161         if (rxrpc_get_local_maybe(local)) {
1162                 skb_queue_tail(&local->event_queue, skb);
1163                 rxrpc_queue_local(local);
1164         } else {
1165                 rxrpc_free_skb(skb, rxrpc_skb_freed);
1166         }
1167 }
1168
1169 /*
1170  * put a packet up for transport-level abort
1171  */
1172 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1173 {
1174         if (rxrpc_get_local_maybe(local)) {
1175                 skb_queue_tail(&local->reject_queue, skb);
1176                 rxrpc_queue_local(local);
1177         } else {
1178                 rxrpc_free_skb(skb, rxrpc_skb_freed);
1179         }
1180 }
1181
1182 /*
1183  * Extract the wire header from a packet and translate the byte order.
1184  */
1185 static noinline
1186 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1187 {
1188         struct rxrpc_wire_header whdr;
1189
1190         /* dig out the RxRPC connection details */
1191         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1192                 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1193                                       tracepoint_string("bad_hdr"));
1194                 return -EBADMSG;
1195         }
1196
1197         memset(sp, 0, sizeof(*sp));
1198         sp->hdr.epoch           = ntohl(whdr.epoch);
1199         sp->hdr.cid             = ntohl(whdr.cid);
1200         sp->hdr.callNumber      = ntohl(whdr.callNumber);
1201         sp->hdr.seq             = ntohl(whdr.seq);
1202         sp->hdr.serial          = ntohl(whdr.serial);
1203         sp->hdr.flags           = whdr.flags;
1204         sp->hdr.type            = whdr.type;
1205         sp->hdr.userStatus      = whdr.userStatus;
1206         sp->hdr.securityIndex   = whdr.securityIndex;
1207         sp->hdr._rsvd           = ntohs(whdr._rsvd);
1208         sp->hdr.serviceId       = ntohs(whdr.serviceId);
1209         return 0;
1210 }
1211
1212 /*
1213  * handle data received on the local endpoint
1214  * - may be called in interrupt context
1215  *
1216  * [!] Note that as this is called from the encap_rcv hook, the socket is not
1217  * held locked by the caller and nothing prevents sk_user_data on the UDP from
1218  * being cleared in the middle of processing this function.
1219  *
1220  * Called with the RCU read lock held from the IP layer via UDP.
1221  */
1222 int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
1223 {
1224         struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
1225         struct rxrpc_connection *conn;
1226         struct rxrpc_channel *chan;
1227         struct rxrpc_call *call = NULL;
1228         struct rxrpc_skb_priv *sp;
1229         struct rxrpc_peer *peer = NULL;
1230         struct rxrpc_sock *rx = NULL;
1231         unsigned int channel;
1232
1233         _enter("%p", udp_sk);
1234
1235         if (unlikely(!local)) {
1236                 kfree_skb(skb);
1237                 return 0;
1238         }
1239         if (skb->tstamp == 0)
1240                 skb->tstamp = ktime_get_real();
1241
1242         rxrpc_new_skb(skb, rxrpc_skb_received);
1243
1244         skb_pull(skb, sizeof(struct udphdr));
1245
1246         /* The UDP protocol already released all skb resources;
1247          * we are free to add our own data there.
1248          */
1249         sp = rxrpc_skb(skb);
1250
1251         /* dig out the RxRPC connection details */
1252         if (rxrpc_extract_header(sp, skb) < 0)
1253                 goto bad_message;
1254
1255         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1256                 static int lose;
1257                 if ((lose++ & 7) == 7) {
1258                         trace_rxrpc_rx_lose(sp);
1259                         rxrpc_free_skb(skb, rxrpc_skb_lost);
1260                         return 0;
1261                 }
1262         }
1263
1264         if (skb->tstamp == 0)
1265                 skb->tstamp = ktime_get_real();
1266         trace_rxrpc_rx_packet(sp);
1267
1268         switch (sp->hdr.type) {
1269         case RXRPC_PACKET_TYPE_VERSION:
1270                 if (rxrpc_to_client(sp))
1271                         goto discard;
1272                 rxrpc_post_packet_to_local(local, skb);
1273                 goto out;
1274
1275         case RXRPC_PACKET_TYPE_BUSY:
1276                 if (rxrpc_to_server(sp))
1277                         goto discard;
1278                 fallthrough;
1279         case RXRPC_PACKET_TYPE_ACK:
1280         case RXRPC_PACKET_TYPE_ACKALL:
1281                 if (sp->hdr.callNumber == 0)
1282                         goto bad_message;
1283                 fallthrough;
1284         case RXRPC_PACKET_TYPE_ABORT:
1285                 break;
1286
1287         case RXRPC_PACKET_TYPE_DATA:
1288                 if (sp->hdr.callNumber == 0 ||
1289                     sp->hdr.seq == 0)
1290                         goto bad_message;
1291                 if (!rxrpc_validate_data(skb))
1292                         goto bad_message;
1293
1294                 /* Unshare the packet so that it can be modified for in-place
1295                  * decryption.
1296                  */
1297                 if (sp->hdr.securityIndex != 0) {
1298                         struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC);
1299                         if (!nskb) {
1300                                 rxrpc_eaten_skb(skb, rxrpc_skb_unshared_nomem);
1301                                 goto out;
1302                         }
1303
1304                         if (nskb != skb) {
1305                                 rxrpc_eaten_skb(skb, rxrpc_skb_received);
1306                                 skb = nskb;
1307                                 rxrpc_new_skb(skb, rxrpc_skb_unshared);
1308                                 sp = rxrpc_skb(skb);
1309                         }
1310                 }
1311                 break;
1312
1313         case RXRPC_PACKET_TYPE_CHALLENGE:
1314                 if (rxrpc_to_server(sp))
1315                         goto discard;
1316                 break;
1317         case RXRPC_PACKET_TYPE_RESPONSE:
1318                 if (rxrpc_to_client(sp))
1319                         goto discard;
1320                 break;
1321
1322                 /* Packet types 9-11 should just be ignored. */
1323         case RXRPC_PACKET_TYPE_PARAMS:
1324         case RXRPC_PACKET_TYPE_10:
1325         case RXRPC_PACKET_TYPE_11:
1326                 goto discard;
1327
1328         default:
1329                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
1330                 goto bad_message;
1331         }
1332
1333         if (sp->hdr.serviceId == 0)
1334                 goto bad_message;
1335
1336         if (rxrpc_to_server(sp)) {
1337                 /* Weed out packets to services we're not offering.  Packets
1338                  * that would begin a call are explicitly rejected and the rest
1339                  * are just discarded.
1340                  */
1341                 rx = rcu_dereference(local->service);
1342                 if (!rx || (sp->hdr.serviceId != rx->srx.srx_service &&
1343                             sp->hdr.serviceId != rx->second_service)) {
1344                         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
1345                             sp->hdr.seq == 1)
1346                                 goto unsupported_service;
1347                         goto discard;
1348                 }
1349         }
1350
1351         conn = rxrpc_find_connection_rcu(local, skb, &peer);
1352         if (conn) {
1353                 if (sp->hdr.securityIndex != conn->security_ix)
1354                         goto wrong_security;
1355
1356                 if (sp->hdr.serviceId != conn->service_id) {
1357                         int old_id;
1358
1359                         if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags))
1360                                 goto reupgrade;
1361                         old_id = cmpxchg(&conn->service_id, conn->params.service_id,
1362                                          sp->hdr.serviceId);
1363
1364                         if (old_id != conn->params.service_id &&
1365                             old_id != sp->hdr.serviceId)
1366                                 goto reupgrade;
1367                 }
1368
1369                 if (sp->hdr.callNumber == 0) {
1370                         /* Connection-level packet */
1371                         _debug("CONN %p {%d}", conn, conn->debug_id);
1372                         rxrpc_post_packet_to_conn(conn, skb);
1373                         goto out;
1374                 }
1375
1376                 if ((int)sp->hdr.serial - (int)conn->hi_serial > 0)
1377                         conn->hi_serial = sp->hdr.serial;
1378
1379                 /* Call-bound packets are routed by connection channel. */
1380                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1381                 chan = &conn->channels[channel];
1382
1383                 /* Ignore really old calls */
1384                 if (sp->hdr.callNumber < chan->last_call)
1385                         goto discard;
1386
1387                 if (sp->hdr.callNumber == chan->last_call) {
1388                         if (chan->call ||
1389                             sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
1390                                 goto discard;
1391
1392                         /* For the previous service call, if completed
1393                          * successfully, we discard all further packets.
1394                          */
1395                         if (rxrpc_conn_is_service(conn) &&
1396                             chan->last_type == RXRPC_PACKET_TYPE_ACK)
1397                                 goto discard;
1398
1399                         /* But otherwise we need to retransmit the final packet
1400                          * from data cached in the connection record.
1401                          */
1402                         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
1403                                 trace_rxrpc_rx_data(chan->call_debug_id,
1404                                                     sp->hdr.seq,
1405                                                     sp->hdr.serial,
1406                                                     sp->hdr.flags, 0);
1407                         rxrpc_post_packet_to_conn(conn, skb);
1408                         goto out;
1409                 }
1410
1411                 call = rcu_dereference(chan->call);
1412
1413                 if (sp->hdr.callNumber > chan->call_id) {
1414                         if (rxrpc_to_client(sp))
1415                                 goto reject_packet;
1416                         if (call)
1417                                 rxrpc_input_implicit_end_call(rx, conn, call);
1418                         call = NULL;
1419                 }
1420
1421                 if (call) {
1422                         if (sp->hdr.serviceId != call->service_id)
1423                                 call->service_id = sp->hdr.serviceId;
1424                         if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
1425                                 call->rx_serial = sp->hdr.serial;
1426                         if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
1427                                 set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
1428                 }
1429         }
1430
1431         if (!call || refcount_read(&call->ref) == 0) {
1432                 if (rxrpc_to_client(sp) ||
1433                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1434                         goto bad_message;
1435                 if (sp->hdr.seq != 1)
1436                         goto discard;
1437                 call = rxrpc_new_incoming_call(local, rx, skb);
1438                 if (!call)
1439                         goto reject_packet;
1440         }
1441
1442         /* Process a call packet; this either discards or passes on the ref
1443          * elsewhere.
1444          */
1445         rxrpc_input_call_packet(call, skb);
1446         goto out;
1447
1448 discard:
1449         rxrpc_free_skb(skb, rxrpc_skb_freed);
1450 out:
1451         trace_rxrpc_rx_done(0, 0);
1452         return 0;
1453
1454 wrong_security:
1455         trace_rxrpc_abort(0, "SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1456                           RXKADINCONSISTENCY, EBADMSG);
1457         skb->priority = RXKADINCONSISTENCY;
1458         goto post_abort;
1459
1460 unsupported_service:
1461         trace_rxrpc_abort(0, "INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1462                           RX_INVALID_OPERATION, EOPNOTSUPP);
1463         skb->priority = RX_INVALID_OPERATION;
1464         goto post_abort;
1465
1466 reupgrade:
1467         trace_rxrpc_abort(0, "UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1468                           RX_PROTOCOL_ERROR, EBADMSG);
1469         goto protocol_error;
1470
1471 bad_message:
1472         trace_rxrpc_abort(0, "BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1473                           RX_PROTOCOL_ERROR, EBADMSG);
1474 protocol_error:
1475         skb->priority = RX_PROTOCOL_ERROR;
1476 post_abort:
1477         skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
1478 reject_packet:
1479         trace_rxrpc_rx_done(skb->mark, skb->priority);
1480         rxrpc_reject_packet(local, skb);
1481         _leave(" [badmsg]");
1482         return 0;
1483 }