net/rxrpc/input.c

   1 /* RxRPC packet reception
   2  *
   3  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/net.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/errqueue.h>
  18 #include <linux/udp.h>
  19 #include <linux/in.h>
  20 #include <linux/in6.h>
  21 #include <linux/icmp.h>
  22 #include <linux/gfp.h>
  23 #include <net/sock.h>
  24 #include <net/af_rxrpc.h>
  25 #include <net/ip.h>
  26 #include <net/udp.h>
  27 #include <net/net_namespace.h>
  28 #include "ar-internal.h"
  29
  30 static void rxrpc_proto_abort(const char *why,
  31                               struct rxrpc_call *call, rxrpc_seq_t seq)
  32 {
  33         if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) {
  34                 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
  35                 rxrpc_queue_call(call);
  36         }
  37 }
  38
  39 /*
  40  * Do TCP-style congestion management [RFC 5681].
  41  */
  42 static void rxrpc_congestion_management(struct rxrpc_call *call,
  43                                         struct sk_buff *skb,
  44                                         struct rxrpc_ack_summary *summary,
  45                                         rxrpc_serial_t acked_serial)
  46 {
  47         enum rxrpc_congest_change change = rxrpc_cong_no_change;
  48         unsigned int cumulative_acks = call->cong_cumul_acks;
  49         unsigned int cwnd = call->cong_cwnd;
  50         bool resend = false;
  51
  52         summary->flight_size =
  53                 (call->tx_top - call->tx_hard_ack) - summary->nr_acks;
  54
  55         if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
  56                 summary->retrans_timeo = true;
  57                 call->cong_ssthresh = max_t(unsigned int,
  58                                             summary->flight_size / 2, 2);
  59                 cwnd = 1;
  60                 if (cwnd >= call->cong_ssthresh &&
  61                     call->cong_mode == RXRPC_CALL_SLOW_START) {
  62                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  63                         call->cong_tstamp = skb->tstamp;
  64                         cumulative_acks = 0;
  65                 }
  66         }
  67
  68         cumulative_acks += summary->nr_new_acks;
  69         cumulative_acks += summary->nr_rot_new_acks;
  70         if (cumulative_acks > 255)
  71                 cumulative_acks = 255;
  72
  73         summary->mode = call->cong_mode;
  74         summary->cwnd = call->cong_cwnd;
  75         summary->ssthresh = call->cong_ssthresh;
  76         summary->cumulative_acks = cumulative_acks;
  77         summary->dup_acks = call->cong_dup_acks;
  78
  79         switch (call->cong_mode) {
  80         case RXRPC_CALL_SLOW_START:
  81                 if (summary->nr_nacks > 0)
  82                         goto packet_loss_detected;
  83                 if (summary->cumulative_acks > 0)
  84                         cwnd += 1;
  85                 if (cwnd >= call->cong_ssthresh) {
  86                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  87                         call->cong_tstamp = skb->tstamp;
  88                 }
  89                 goto out;
  90
  91         case RXRPC_CALL_CONGEST_AVOIDANCE:
  92                 if (summary->nr_nacks > 0)
  93                         goto packet_loss_detected;
  94
  95                 /* We analyse the number of packets that get ACK'd per RTT
  96                  * period and increase the window if we managed to fill it.
  97                  */
  98                 if (call->peer->rtt_usage == 0)
  99                         goto out;
 100                 if (ktime_before(skb->tstamp,
 101                                  ktime_add_ns(call->cong_tstamp,
 102                                               call->peer->rtt)))
 103                         goto out_no_clear_ca;
 104                 change = rxrpc_cong_rtt_window_end;
 105                 call->cong_tstamp = skb->tstamp;
 106                 if (cumulative_acks >= cwnd)
 107                         cwnd++;
 108                 goto out;
 109
 110         case RXRPC_CALL_PACKET_LOSS:
 111                 if (summary->nr_nacks == 0)
 112                         goto resume_normality;
 113
 114                 if (summary->new_low_nack) {
 115                         change = rxrpc_cong_new_low_nack;
 116                         call->cong_dup_acks = 1;
 117                         if (call->cong_extra > 1)
 118                                 call->cong_extra = 1;
 119                         goto send_extra_data;
 120                 }
 121
 122                 call->cong_dup_acks++;
 123                 if (call->cong_dup_acks < 3)
 124                         goto send_extra_data;
 125
 126                 change = rxrpc_cong_begin_retransmission;
 127                 call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
 128                 call->cong_ssthresh = max_t(unsigned int,
 129                                             summary->flight_size / 2, 2);
 130                 cwnd = call->cong_ssthresh + 3;
 131                 call->cong_extra = 0;
 132                 call->cong_dup_acks = 0;
 133                 resend = true;
 134                 goto out;
 135
 136         case RXRPC_CALL_FAST_RETRANSMIT:
 137                 if (!summary->new_low_nack) {
 138                         if (summary->nr_new_acks == 0)
 139                                 cwnd += 1;
 140                         call->cong_dup_acks++;
 141                         if (call->cong_dup_acks == 2) {
 142                                 change = rxrpc_cong_retransmit_again;
 143                                 call->cong_dup_acks = 0;
 144                                 resend = true;
 145                         }
 146                 } else {
 147                         change = rxrpc_cong_progress;
 148                         cwnd = call->cong_ssthresh;
 149                         if (summary->nr_nacks == 0)
 150                                 goto resume_normality;
 151                 }
 152                 goto out;
 153
 154         default:
 155                 BUG();
 156                 goto out;
 157         }
 158
 159 resume_normality:
 160         change = rxrpc_cong_cleared_nacks;
 161         call->cong_dup_acks = 0;
 162         call->cong_extra = 0;
 163         call->cong_tstamp = skb->tstamp;
 164         if (cwnd < call->cong_ssthresh)
 165                 call->cong_mode = RXRPC_CALL_SLOW_START;
 166         else
 167                 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
 168 out:
 169         cumulative_acks = 0;
 170 out_no_clear_ca:
 171         if (cwnd >= RXRPC_RXTX_BUFF_SIZE - 1)
 172                 cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
 173         call->cong_cwnd = cwnd;
 174         call->cong_cumul_acks = cumulative_acks;
 175         trace_rxrpc_congest(call, summary, acked_serial, change);
 176         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 177                 rxrpc_queue_call(call);
 178         return;
 179
 180 packet_loss_detected:
 181         change = rxrpc_cong_saw_nack;
 182         call->cong_mode = RXRPC_CALL_PACKET_LOSS;
 183         call->cong_dup_acks = 0;
 184         goto send_extra_data;
 185
 186 send_extra_data:
 187         /* Send some previously unsent DATA if we have some to advance the ACK
 188          * state.
 189          */
 190         if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
 191             RXRPC_TX_ANNO_LAST ||
 192             summary->nr_acks != call->tx_top - call->tx_hard_ack) {
 193                 call->cong_extra++;
 194                 wake_up(&call->waitq);
 195         }
 196         goto out_no_clear_ca;
 197 }
 198
 199 /*
 200  * Ping the other end to fill our RTT cache and to retrieve the rwind
 201  * and MTU parameters.
 202  */
 203 static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb,
 204                             int skew)
 205 {
 206         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 207         ktime_t now = skb->tstamp;
 208
 209         if (call->peer->rtt_usage < 3 ||
 210             ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
 211                 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
 212                                   true, true,
 213                                   rxrpc_propose_ack_ping_for_params);
 214 }
 215
 216 /*
 217  * Apply a hard ACK by advancing the Tx window.
 218  */
 219 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 220                                    struct rxrpc_ack_summary *summary)
 221 {
 222         struct sk_buff *skb, *list = NULL;
 223         int ix;
 224         u8 annotation;
 225
 226         if (call->acks_lowest_nak == call->tx_hard_ack) {
 227                 call->acks_lowest_nak = to;
 228         } else if (before_eq(call->acks_lowest_nak, to)) {
 229                 summary->new_low_nack = true;
 230                 call->acks_lowest_nak = to;
 231         }
 232
 233         spin_lock(&call->lock);
 234
 235         while (before(call->tx_hard_ack, to)) {
 236                 call->tx_hard_ack++;
 237                 ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
 238                 skb = call->rxtx_buffer[ix];
 239                 annotation = call->rxtx_annotations[ix];
 240                 rxrpc_see_skb(skb, rxrpc_skb_tx_rotated);
 241                 call->rxtx_buffer[ix] = NULL;
 242                 call->rxtx_annotations[ix] = 0;
 243                 skb->next = list;
 244                 list = skb;
 245
 246                 if (annotation & RXRPC_TX_ANNO_LAST)
 247                         set_bit(RXRPC_CALL_TX_LAST, &call->flags);
 248                 if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK)
 249                         summary->nr_rot_new_acks++;
 250         }
 251
 252         spin_unlock(&call->lock);
 253
 254         trace_rxrpc_transmit(call, (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ?
 255                                     rxrpc_transmit_rotate_last :
 256                                     rxrpc_transmit_rotate));
 257         wake_up(&call->waitq);
 258
 259         while (list) {
 260                 skb = list;
 261                 list = skb->next;
 262                 skb->next = NULL;
 263                 rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
 264         }
 265 }
 266
 267 /*
 268  * End the transmission phase of a call.
 269  *
 270  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 271  * or a final ACK packet.
 272  */
 273 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 274                                const char *abort_why)
 275 {
 276
 277         ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 278
 279         write_lock(&call->state_lock);
 280
 281         switch (call->state) {
 282         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 283         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 284                 if (reply_begun)
 285                         call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 286                 else
 287                         call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 288                 break;
 289
 290         case RXRPC_CALL_SERVER_AWAIT_ACK:
 291                 __rxrpc_call_completed(call);
 292                 rxrpc_notify_socket(call);
 293                 break;
 294
 295         default:
 296                 goto bad_state;
 297         }
 298
 299         write_unlock(&call->state_lock);
 300         if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY) {
 301                 trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
 302         } else {
 303                 trace_rxrpc_transmit(call, rxrpc_transmit_end);
 304         }
 305         _leave(" = ok");
 306         return true;
 307
 308 bad_state:
 309         write_unlock(&call->state_lock);
 310         kdebug("end_tx %s", rxrpc_call_states[call->state]);
 311         rxrpc_proto_abort(abort_why, call, call->tx_top);
 312         return false;
 313 }
 314
 315 /*
 316  * Begin the reply reception phase of a call.
 317  */
 318 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 319 {
 320         struct rxrpc_ack_summary summary = { 0 };
 321         unsigned long now, timo;
 322         rxrpc_seq_t top = READ_ONCE(call->tx_top);
 323
 324         if (call->ackr_reason) {
 325                 spin_lock_bh(&call->lock);
 326                 call->ackr_reason = 0;
 327                 spin_unlock_bh(&call->lock);
 328                 now = jiffies;
 329                 timo = now + MAX_JIFFY_OFFSET;
 330                 WRITE_ONCE(call->resend_at, timo);
 331                 WRITE_ONCE(call->ack_at, timo);
 332                 trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
 333         }
 334
 335         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 336                 rxrpc_rotate_tx_window(call, top, &summary);
 337         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 338                 rxrpc_proto_abort("TXL", call, top);
 339                 return false;
 340         }
 341         if (!rxrpc_end_tx_phase(call, true, "ETD"))
 342                 return false;
 343         call->tx_phase = false;
 344         return true;
 345 }
 346
 347 /*
 348  * Scan a jumbo packet to validate its structure and to work out how many
 349  * subpackets it contains.
 350  *
 351  * A jumbo packet is a collection of consecutive packets glued together with
 352  * little headers between that indicate how to change the initial header for
 353  * each subpacket.
 354  *
 355  * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 356  * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 357  * size.
 358  */
 359 static bool rxrpc_validate_jumbo(struct sk_buff *skb)
 360 {
 361         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 362         unsigned int offset = sizeof(struct rxrpc_wire_header);
 363         unsigned int len = skb->len;
 364         int nr_jumbo = 1;
 365         u8 flags = sp->hdr.flags;
 366
 367         do {
 368                 nr_jumbo++;
 369                 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 370                         goto protocol_error;
 371                 if (flags & RXRPC_LAST_PACKET)
 372                         goto protocol_error;
 373                 offset += RXRPC_JUMBO_DATALEN;
 374                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 375                         goto protocol_error;
 376                 offset += sizeof(struct rxrpc_jumbo_header);
 377         } while (flags & RXRPC_JUMBO_PACKET);
 378
 379         sp->nr_jumbo = nr_jumbo;
 380         return true;
 381
 382 protocol_error:
 383         return false;
 384 }
 385
 386 /*
 387  * Handle reception of a duplicate packet.
 388  *
 389  * We have to take care to avoid an attack here whereby we're given a series of
 390  * jumbograms, each with a sequence number one before the preceding one and
 391  * filled up to maximum UDP size.  If they never send us the first packet in
 392  * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 393  * space until the call times out.
 394  *
 395  * We limit the space usage by only accepting three duplicate jumbo packets per
 396  * call.  After that, we tell the other side we're no longer accepting jumbos
 397  * (that information is encoded in the ACK packet).
 398  */
 399 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 400                                  u8 annotation, bool *_jumbo_bad)
 401 {
 402         /* Discard normal packets that are duplicates. */
 403         if (annotation == 0)
 404                 return;
 405
 406         /* Skip jumbo subpackets that are duplicates.  When we've had three or
 407          * more partially duplicate jumbo packets, we refuse to take any more
 408          * jumbos for this call.
 409          */
 410         if (!*_jumbo_bad) {
 411                 call->nr_jumbo_bad++;
 412                 *_jumbo_bad = true;
 413         }
 414 }
 415
 416 /*
 417  * Process a DATA packet, adding the packet to the Rx ring.
 418  */
 419 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
 420                              u16 skew)
 421 {
 422         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 423         enum rxrpc_call_state state;
 424         unsigned int offset = sizeof(struct rxrpc_wire_header);
 425         unsigned int ix;
 426         rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
 427         rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
 428         bool immediate_ack = false, jumbo_bad = false, queued;
 429         u16 len;
 430         u8 ack = 0, flags, annotation = 0;
 431
 432         _enter("{%u,%u},{%u,%u}",
 433                call->rx_hard_ack, call->rx_top, skb->len, seq);
 434
 435         _proto("Rx DATA %%%u { #%u f=%02x }",
 436                sp->hdr.serial, seq, sp->hdr.flags);
 437
 438         state = READ_ONCE(call->state);
 439         if (state >= RXRPC_CALL_COMPLETE)
 440                 return;
 441
 442         if (call->state == RXRPC_CALL_SERVER_RECV_REQUEST) {
 443                 unsigned long timo = READ_ONCE(call->next_req_timo);
 444                 unsigned long now, expect_req_by;
 445
 446                 if (timo) {
 447                         now = jiffies;
 448                         expect_req_by = now + timo;
 449                         WRITE_ONCE(call->expect_req_by, expect_req_by);
 450                         rxrpc_reduce_call_timer(call, expect_req_by, now,
 451                                                 rxrpc_timer_set_for_idle);
 452                 }
 453         }
 454
 455         /* Received data implicitly ACKs all of the request packets we sent
 456          * when we're acting as a client.
 457          */
 458         if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 459              state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 460             !rxrpc_receiving_reply(call))
 461                 return;
 462
 463         call->ackr_prev_seq = seq;
 464
 465         hard_ack = READ_ONCE(call->rx_hard_ack);
 466         if (after(seq, hard_ack + call->rx_winsize)) {
 467                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 468                 ack_serial = serial;
 469                 goto ack;
 470         }
 471
 472         flags = sp->hdr.flags;
 473         if (flags & RXRPC_JUMBO_PACKET) {
 474                 if (call->nr_jumbo_bad > 3) {
 475                         ack = RXRPC_ACK_NOSPACE;
 476                         ack_serial = serial;
 477                         goto ack;
 478                 }
 479                 annotation = 1;
 480         }
 481
 482 next_subpacket:
 483         queued = false;
 484         ix = seq & RXRPC_RXTX_BUFF_MASK;
 485         len = skb->len;
 486         if (flags & RXRPC_JUMBO_PACKET)
 487                 len = RXRPC_JUMBO_DATALEN;
 488
 489         if (flags & RXRPC_LAST_PACKET) {
 490                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 491                     seq != call->rx_top)
 492                         return rxrpc_proto_abort("LSN", call, seq);
 493         } else {
 494                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 495                     after_eq(seq, call->rx_top))
 496                         return rxrpc_proto_abort("LSA", call, seq);
 497         }
 498
 499         trace_rxrpc_rx_data(call, seq, serial, flags, annotation);
 500         if (before_eq(seq, hard_ack)) {
 501                 ack = RXRPC_ACK_DUPLICATE;
 502                 ack_serial = serial;
 503                 goto skip;
 504         }
 505
 506         if (flags & RXRPC_REQUEST_ACK && !ack) {
 507                 ack = RXRPC_ACK_REQUESTED;
 508                 ack_serial = serial;
 509         }
 510
 511         if (call->rxtx_buffer[ix]) {
 512                 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
 513                 if (ack != RXRPC_ACK_DUPLICATE) {
 514                         ack = RXRPC_ACK_DUPLICATE;
 515                         ack_serial = serial;
 516                 }
 517                 immediate_ack = true;
 518                 goto skip;
 519         }
 520
 521         /* Queue the packet.  We use a couple of memory barriers here as need
 522          * to make sure that rx_top is perceived to be set after the buffer
 523          * pointer and that the buffer pointer is set after the annotation and
 524          * the skb data.
 525          *
 526          * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 527          * and also rxrpc_fill_out_ack().
 528          */
 529         rxrpc_get_skb(skb, rxrpc_skb_rx_got);
 530         call->rxtx_annotations[ix] = annotation;
 531         smp_wmb();
 532         call->rxtx_buffer[ix] = skb;
 533         if (after(seq, call->rx_top)) {
 534                 smp_store_release(&call->rx_top, seq);
 535         } else if (before(seq, call->rx_top)) {
 536                 /* Send an immediate ACK if we fill in a hole */
 537                 if (!ack) {
 538                         ack = RXRPC_ACK_DELAY;
 539                         ack_serial = serial;
 540                 }
 541                 immediate_ack = true;
 542         }
 543         if (flags & RXRPC_LAST_PACKET) {
 544                 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 545                 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 546         } else {
 547                 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 548         }
 549         queued = true;
 550
 551         if (after_eq(seq, call->rx_expect_next)) {
 552                 if (after(seq, call->rx_expect_next)) {
 553                         _net("OOS %u > %u", seq, call->rx_expect_next);
 554                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 555                         ack_serial = serial;
 556                 }
 557                 call->rx_expect_next = seq + 1;
 558         }
 559
 560 skip:
 561         offset += len;
 562         if (flags & RXRPC_JUMBO_PACKET) {
 563                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 564                         return rxrpc_proto_abort("XJF", call, seq);
 565                 offset += sizeof(struct rxrpc_jumbo_header);
 566                 seq++;
 567                 serial++;
 568                 annotation++;
 569                 if (flags & RXRPC_JUMBO_PACKET)
 570                         annotation |= RXRPC_RX_ANNO_JLAST;
 571                 if (after(seq, hard_ack + call->rx_winsize)) {
 572                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
 573                         ack_serial = serial;
 574                         if (!jumbo_bad) {
 575                                 call->nr_jumbo_bad++;
 576                                 jumbo_bad = true;
 577                         }
 578                         goto ack;
 579                 }
 580
 581                 _proto("Rx DATA Jumbo %%%u", serial);
 582                 goto next_subpacket;
 583         }
 584
 585         if (queued && flags & RXRPC_LAST_PACKET && !ack) {
 586                 ack = RXRPC_ACK_DELAY;
 587                 ack_serial = serial;
 588         }
 589
 590 ack:
 591         if (ack)
 592                 rxrpc_propose_ACK(call, ack, skew, ack_serial,
 593                                   immediate_ack, true,
 594                                   rxrpc_propose_ack_input_data);
 595
 596         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
 597                 rxrpc_notify_socket(call);
 598         _leave(" [queued]");
 599 }
 600
 601 /*
 602  * Process a requested ACK.
 603  */
 604 static void rxrpc_input_requested_ack(struct rxrpc_call *call,
 605                                       ktime_t resp_time,
 606                                       rxrpc_serial_t orig_serial,
 607                                       rxrpc_serial_t ack_serial)
 608 {
 609         struct rxrpc_skb_priv *sp;
 610         struct sk_buff *skb;
 611         ktime_t sent_at;
 612         int ix;
 613
 614         for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
 615                 skb = call->rxtx_buffer[ix];
 616                 if (!skb)
 617                         continue;
 618
 619                 sp = rxrpc_skb(skb);
 620                 if (sp->hdr.serial != orig_serial)
 621                         continue;
 622                 smp_rmb();
 623                 sent_at = skb->tstamp;
 624                 goto found;
 625         }
 626         return;
 627
 628 found:
 629         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
 630                            orig_serial, ack_serial, sent_at, resp_time);
 631 }
 632
 633 /*
 634  * Process the response to a ping that we sent to find out if we lost an ACK.
 635  *
 636  * If we got back a ping response that indicates a lower tx_top than what we
 637  * had at the time of the ping transmission, we adjudge all the DATA packets
 638  * sent between the response tx_top and the ping-time tx_top to have been lost.
 639  */
 640 static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
 641 {
 642         rxrpc_seq_t top, bottom, seq;
 643         bool resend = false;
 644
 645         spin_lock_bh(&call->lock);
 646
 647         bottom = call->tx_hard_ack + 1;
 648         top = call->acks_lost_top;
 649         if (before(bottom, top)) {
 650                 for (seq = bottom; before_eq(seq, top); seq++) {
 651                         int ix = seq & RXRPC_RXTX_BUFF_MASK;
 652                         u8 annotation = call->rxtx_annotations[ix];
 653                         u8 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 654
 655                         if (anno_type != RXRPC_TX_ANNO_UNACK)
 656                                 continue;
 657                         annotation &= ~RXRPC_TX_ANNO_MASK;
 658                         annotation |= RXRPC_TX_ANNO_RETRANS;
 659                         call->rxtx_annotations[ix] = annotation;
 660                         resend = true;
 661                 }
 662         }
 663
 664         spin_unlock_bh(&call->lock);
 665
 666         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 667                 rxrpc_queue_call(call);
 668 }
 669
 670 /*
 671  * Process a ping response.
 672  */
 673 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 674                                       ktime_t resp_time,
 675                                       rxrpc_serial_t orig_serial,
 676                                       rxrpc_serial_t ack_serial)
 677 {
 678         rxrpc_serial_t ping_serial;
 679         ktime_t ping_time;
 680
 681         ping_time = call->ping_time;
 682         smp_rmb();
 683         ping_serial = call->ping_serial;
 684
 685         if (orig_serial == call->acks_lost_ping)
 686                 rxrpc_input_check_for_lost_ack(call);
 687
 688         if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
 689             before(orig_serial, ping_serial))
 690                 return;
 691         clear_bit(RXRPC_CALL_PINGING, &call->flags);
 692         if (after(orig_serial, ping_serial))
 693                 return;
 694
 695         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
 696                            orig_serial, ack_serial, ping_time, resp_time);
 697 }
 698
 699 /*
 700  * Process the extra information that may be appended to an ACK packet
 701  */
 702 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 703                                 struct rxrpc_ackinfo *ackinfo)
 704 {
 705         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 706         struct rxrpc_peer *peer;
 707         unsigned int mtu;
 708         bool wake = false;
 709         u32 rwind = ntohl(ackinfo->rwind);
 710
 711         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 712                sp->hdr.serial,
 713                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 714                rwind, ntohl(ackinfo->jumbo_max));
 715
 716         if (call->tx_winsize != rwind) {
 717                 if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 718                         rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 719                 if (rwind > call->tx_winsize)
 720                         wake = true;
 721                 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial,
 722                                             ntohl(ackinfo->rwind), wake);
 723                 call->tx_winsize = rwind;
 724         }
 725
 726         if (call->cong_ssthresh > rwind)
 727                 call->cong_ssthresh = rwind;
 728
 729         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 730
 731         peer = call->peer;
 732         if (mtu < peer->maxdata) {
 733                 spin_lock_bh(&peer->lock);
 734                 peer->maxdata = mtu;
 735                 peer->mtu = mtu + peer->hdrsize;
 736                 spin_unlock_bh(&peer->lock);
 737                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 738         }
 739
 740         if (wake)
 741                 wake_up(&call->waitq);
 742 }
 743
 744 /*
 745  * Process individual soft ACKs.
 746  *
 747  * Each ACK in the array corresponds to one packet and can be either an ACK or
 748  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 749  * packets that lie beyond the end of the ACK list are scheduled for resend by
 750  * the timer on the basis that the peer might just not have processed them at
 751  * the time the ACK was sent.
 752  */
 753 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 754                                   rxrpc_seq_t seq, int nr_acks,
 755                                   struct rxrpc_ack_summary *summary)
 756 {
 757         int ix;
 758         u8 annotation, anno_type;
 759
 760         for (; nr_acks > 0; nr_acks--, seq++) {
 761                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 762                 annotation = call->rxtx_annotations[ix];
 763                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 764                 annotation &= ~RXRPC_TX_ANNO_MASK;
 765                 switch (*acks++) {
 766                 case RXRPC_ACK_TYPE_ACK:
 767                         summary->nr_acks++;
 768                         if (anno_type == RXRPC_TX_ANNO_ACK)
 769                                 continue;
 770                         summary->nr_new_acks++;
 771                         call->rxtx_annotations[ix] =
 772                                 RXRPC_TX_ANNO_ACK | annotation;
 773                         break;
 774                 case RXRPC_ACK_TYPE_NACK:
 775                         if (!summary->nr_nacks &&
 776                             call->acks_lowest_nak != seq) {
 777                                 call->acks_lowest_nak = seq;
 778                                 summary->new_low_nack = true;
 779                         }
 780                         summary->nr_nacks++;
 781                         if (anno_type == RXRPC_TX_ANNO_NAK)
 782                                 continue;
 783                         summary->nr_new_nacks++;
 784                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
 785                                 continue;
 786                         call->rxtx_annotations[ix] =
 787                                 RXRPC_TX_ANNO_NAK | annotation;
 788                         break;
 789                 default:
 790                         return rxrpc_proto_abort("SFT", call, 0);
 791                 }
 792         }
 793 }
 794
 795 /*
 796  * Process an ACK packet.
 797  *
 798  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 799  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 800  *
 801  * A hard-ACK means that a packet has been processed and may be discarded; a
 802  * soft-ACK means that the packet may be discarded and retransmission
 803  * requested.  A phase is complete when all packets are hard-ACK'd.
 804  */
 805 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 806                             u16 skew)
 807 {
 808         struct rxrpc_ack_summary summary = { 0 };
 809         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 810         union {
 811                 struct rxrpc_ackpacket ack;
 812                 struct rxrpc_ackinfo info;
 813                 u8 acks[RXRPC_MAXACKS];
 814         } buf;
 815         rxrpc_serial_t acked_serial;
 816         rxrpc_seq_t first_soft_ack, hard_ack;
 817         int nr_acks, offset, ioffset;
 818
 819         _enter("");
 820
 821         offset = sizeof(struct rxrpc_wire_header);
 822         if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
 823                 _debug("extraction failure");
 824                 return rxrpc_proto_abort("XAK", call, 0);
 825         }
 826         offset += sizeof(buf.ack);
 827
 828         acked_serial = ntohl(buf.ack.serial);
 829         first_soft_ack = ntohl(buf.ack.firstPacket);
 830         hard_ack = first_soft_ack - 1;
 831         nr_acks = buf.ack.nAcks;
 832         summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 833                               buf.ack.reason : RXRPC_ACK__INVALID);
 834
 835         trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial,
 836                            first_soft_ack, ntohl(buf.ack.previousPacket),
 837                            summary.ack_reason, nr_acks);
 838
 839         if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
 840                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 841                                           sp->hdr.serial);
 842         if (buf.ack.reason == RXRPC_ACK_REQUESTED)
 843                 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
 844                                           sp->hdr.serial);
 845
 846         if (buf.ack.reason == RXRPC_ACK_PING) {
 847                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 848                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 849                                   skew, sp->hdr.serial, true, true,
 850                                   rxrpc_propose_ack_respond_to_ping);
 851         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 852                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 853                                   skew, sp->hdr.serial, true, true,
 854                                   rxrpc_propose_ack_respond_to_ack);
 855         }
 856
 857         ioffset = offset + nr_acks + 3;
 858         if (skb->len >= ioffset + sizeof(buf.info)) {
 859                 if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
 860                         return rxrpc_proto_abort("XAI", call, 0);
 861                 rxrpc_input_ackinfo(call, skb, &buf.info);
 862         }
 863
 864         if (first_soft_ack == 0)
 865                 return rxrpc_proto_abort("AK0", call, 0);
 866
 867         /* Ignore ACKs unless we are or have just been transmitting. */
 868         switch (READ_ONCE(call->state)) {
 869         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 870         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 871         case RXRPC_CALL_SERVER_SEND_REPLY:
 872         case RXRPC_CALL_SERVER_AWAIT_ACK:
 873                 break;
 874         default:
 875                 return;
 876         }
 877
 878         /* Discard any out-of-order or duplicate ACKs. */
 879         if (before_eq(sp->hdr.serial, call->acks_latest)) {
 880                 _debug("discard ACK %d <= %d",
 881                        sp->hdr.serial, call->acks_latest);
 882                 return;
 883         }
 884         call->acks_latest_ts = skb->tstamp;
 885         call->acks_latest = sp->hdr.serial;
 886
 887         if (before(hard_ack, call->tx_hard_ack) ||
 888             after(hard_ack, call->tx_top))
 889                 return rxrpc_proto_abort("AKW", call, 0);
 890         if (nr_acks > call->tx_top - hard_ack)
 891                 return rxrpc_proto_abort("AKN", call, 0);
 892
 893         if (after(hard_ack, call->tx_hard_ack))
 894                 rxrpc_rotate_tx_window(call, hard_ack, &summary);
 895
 896         if (nr_acks > 0) {
 897                 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0)
 898                         return rxrpc_proto_abort("XSA", call, 0);
 899                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
 900                                       &summary);
 901         }
 902
 903         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 904                 rxrpc_end_tx_phase(call, false, "ETA");
 905                 return;
 906         }
 907
 908         if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
 909             RXRPC_TX_ANNO_LAST &&
 910             summary.nr_acks == call->tx_top - hard_ack &&
 911             rxrpc_is_client_call(call))
 912                 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
 913                                   false, true,
 914                                   rxrpc_propose_ack_ping_for_lost_reply);
 915
 916         return rxrpc_congestion_management(call, skb, &summary, acked_serial);
 917 }
 918
 919 /*
 920  * Process an ACKALL packet.
 921  */
 922 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 923 {
 924         struct rxrpc_ack_summary summary = { 0 };
 925         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 926
 927         _proto("Rx ACKALL %%%u", sp->hdr.serial);
 928
 929         rxrpc_rotate_tx_window(call, call->tx_top, &summary);
 930         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 931                 rxrpc_end_tx_phase(call, false, "ETL");
 932 }
 933
 934 /*
 935  * Process an ABORT packet directed at a call.
 936  */
 937 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 938 {
 939         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 940         __be32 wtmp;
 941         u32 abort_code = RX_CALL_DEAD;
 942
 943         _enter("");
 944
 945         if (skb->len >= 4 &&
 946             skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
 947                           &wtmp, sizeof(wtmp)) >= 0)
 948                 abort_code = ntohl(wtmp);
 949
 950         trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
 951
 952         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 953
 954         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 955                                       abort_code, -ECONNABORTED))
 956                 rxrpc_notify_socket(call);
 957 }
 958
 959 /*
 960  * Process an incoming call packet.
 961  */
 962 static void rxrpc_input_call_packet(struct rxrpc_call *call,
 963                                     struct sk_buff *skb, u16 skew)
 964 {
 965         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 966         unsigned long timo;
 967
 968         _enter("%p,%p", call, skb);
 969
 970         timo = READ_ONCE(call->next_rx_timo);
 971         if (timo) {
 972                 unsigned long now = jiffies, expect_rx_by;
 973
 974                 expect_rx_by = jiffies + timo;
 975                 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
 976                 rxrpc_reduce_call_timer(call, expect_rx_by, now,
 977                                         rxrpc_timer_set_for_normal);
 978         }
 979
 980         switch (sp->hdr.type) {
 981         case RXRPC_PACKET_TYPE_DATA:
 982                 rxrpc_input_data(call, skb, skew);
 983                 break;
 984
 985         case RXRPC_PACKET_TYPE_ACK:
 986                 rxrpc_input_ack(call, skb, skew);
 987                 break;
 988
 989         case RXRPC_PACKET_TYPE_BUSY:
 990                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 991
 992                 /* Just ignore BUSY packets from the server; the retry and
 993                  * lifespan timers will take care of business.  BUSY packets
 994                  * from the client don't make sense.
 995                  */
 996                 break;
 997
 998         case RXRPC_PACKET_TYPE_ABORT:
 999                 rxrpc_input_abort(call, skb);
1000                 break;
1001
1002         case RXRPC_PACKET_TYPE_ACKALL:
1003                 rxrpc_input_ackall(call, skb);
1004                 break;
1005
1006         default:
1007                 break;
1008         }
1009
1010         _leave("");
1011 }
1012
1013 /*
1014  * Handle a new call on a channel implicitly completing the preceding call on
1015  * that channel.
1016  *
1017  * TODO: If callNumber > call_id + 1, renegotiate security.
1018  */
1019 static void rxrpc_input_implicit_end_call(struct rxrpc_connection *conn,
1020                                           struct rxrpc_call *call)
1021 {
1022         switch (READ_ONCE(call->state)) {
1023         case RXRPC_CALL_SERVER_AWAIT_ACK:
1024                 rxrpc_call_completed(call);
1025                 break;
1026         case RXRPC_CALL_COMPLETE:
1027                 break;
1028         default:
1029                 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
1030                         set_bit(RXRPC_CALL_EV_ABORT, &call->events);
1031                         rxrpc_queue_call(call);
1032                 }
1033                 break;
1034         }
1035
1036         trace_rxrpc_improper_term(call);
1037         __rxrpc_disconnect_call(conn, call);
1038         rxrpc_notify_socket(call);
1039 }
1040
1041 /*
1042  * post connection-level events to the connection
1043  * - this includes challenges, responses, some aborts and call terminal packet
1044  *   retransmission.
1045  */
1046 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
1047                                       struct sk_buff *skb)
1048 {
1049         _enter("%p,%p", conn, skb);
1050
1051         skb_queue_tail(&conn->rx_queue, skb);
1052         rxrpc_queue_conn(conn);
1053 }
1054
1055 /*
1056  * post endpoint-level events to the local endpoint
1057  * - this includes debug and version messages
1058  */
1059 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
1060                                        struct sk_buff *skb)
1061 {
1062         _enter("%p,%p", local, skb);
1063
1064         skb_queue_tail(&local->event_queue, skb);
1065         rxrpc_queue_local(local);
1066 }
1067
1068 /*
1069  * put a packet up for transport-level abort
1070  */
1071 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1072 {
1073         CHECK_SLAB_OKAY(&local->usage);
1074
1075         skb_queue_tail(&local->reject_queue, skb);
1076         rxrpc_queue_local(local);
1077 }
1078
1079 /*
1080  * Extract the wire header from a packet and translate the byte order.
1081  */
1082 static noinline
1083 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1084 {
1085         struct rxrpc_wire_header whdr;
1086
1087         /* dig out the RxRPC connection details */
1088         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1089                 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1090                                       tracepoint_string("bad_hdr"));
1091                 return -EBADMSG;
1092         }
1093
1094         memset(sp, 0, sizeof(*sp));
1095         sp->hdr.epoch           = ntohl(whdr.epoch);
1096         sp->hdr.cid             = ntohl(whdr.cid);
1097         sp->hdr.callNumber      = ntohl(whdr.callNumber);
1098         sp->hdr.seq             = ntohl(whdr.seq);
1099         sp->hdr.serial          = ntohl(whdr.serial);
1100         sp->hdr.flags           = whdr.flags;
1101         sp->hdr.type            = whdr.type;
1102         sp->hdr.userStatus      = whdr.userStatus;
1103         sp->hdr.securityIndex   = whdr.securityIndex;
1104         sp->hdr._rsvd           = ntohs(whdr._rsvd);
1105         sp->hdr.serviceId       = ntohs(whdr.serviceId);
1106         return 0;
1107 }
1108
1109 /*
1110  * handle data received on the local endpoint
1111  * - may be called in interrupt context
1112  *
1113  * The socket is locked by the caller and this prevents the socket from being
1114  * shut down and the local endpoint from going away, thus sk_user_data will not
1115  * be cleared until this function returns.
1116  */
1117 void rxrpc_data_ready(struct sock *udp_sk)
1118 {
1119         struct rxrpc_connection *conn;
1120         struct rxrpc_channel *chan;
1121         struct rxrpc_call *call;
1122         struct rxrpc_skb_priv *sp;
1123         struct rxrpc_local *local = udp_sk->sk_user_data;
1124         struct sk_buff *skb;
1125         unsigned int channel;
1126         int ret, skew;
1127
1128         _enter("%p", udp_sk);
1129
1130         ASSERT(!irqs_disabled());
1131
1132         skb = skb_recv_udp(udp_sk, 0, 1, &ret);
1133         if (!skb) {
1134                 if (ret == -EAGAIN)
1135                         return;
1136                 _debug("UDP socket error %d", ret);
1137                 return;
1138         }
1139
1140         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
1141
1142         _net("recv skb %p", skb);
1143
1144         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
1145         if (skb_checksum_complete(skb)) {
1146                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1147                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
1148                 _leave(" [CSUM failed]");
1149                 return;
1150         }
1151
1152         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
1153
1154         /* The UDP protocol already released all skb resources;
1155          * we are free to add our own data there.
1156          */
1157         sp = rxrpc_skb(skb);
1158
1159         /* dig out the RxRPC connection details */
1160         if (rxrpc_extract_header(sp, skb) < 0)
1161                 goto bad_message;
1162
1163         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1164                 static int lose;
1165                 if ((lose++ & 7) == 7) {
1166                         trace_rxrpc_rx_lose(sp);
1167                         rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
1168                         return;
1169                 }
1170         }
1171
1172         trace_rxrpc_rx_packet(sp);
1173
1174         _net("Rx RxRPC %s ep=%x call=%x:%x",
1175              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
1176              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
1177
1178         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
1179             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
1180                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
1181                 goto bad_message;
1182         }
1183
1184         switch (sp->hdr.type) {
1185         case RXRPC_PACKET_TYPE_VERSION:
1186                 rxrpc_post_packet_to_local(local, skb);
1187                 goto out;
1188
1189         case RXRPC_PACKET_TYPE_BUSY:
1190                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
1191                         goto discard;
1192                 /* Fall through */
1193
1194         case RXRPC_PACKET_TYPE_DATA:
1195                 if (sp->hdr.callNumber == 0)
1196                         goto bad_message;
1197                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
1198                     !rxrpc_validate_jumbo(skb))
1199                         goto bad_message;
1200                 break;
1201         }
1202
1203         rcu_read_lock();
1204
1205         conn = rxrpc_find_connection_rcu(local, skb);
1206         if (conn) {
1207                 if (sp->hdr.securityIndex != conn->security_ix)
1208                         goto wrong_security;
1209
1210                 if (sp->hdr.serviceId != conn->service_id) {
1211                         if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) ||
1212                             conn->service_id != conn->params.service_id)
1213                                 goto reupgrade;
1214                         conn->service_id = sp->hdr.serviceId;
1215                 }
1216
1217                 if (sp->hdr.callNumber == 0) {
1218                         /* Connection-level packet */
1219                         _debug("CONN %p {%d}", conn, conn->debug_id);
1220                         rxrpc_post_packet_to_conn(conn, skb);
1221                         goto out_unlock;
1222                 }
1223
1224                 /* Note the serial number skew here */
1225                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
1226                 if (skew >= 0) {
1227                         if (skew > 0)
1228                                 conn->hi_serial = sp->hdr.serial;
1229                 } else {
1230                         skew = -skew;
1231                         skew = min(skew, 65535);
1232                 }
1233
1234                 /* Call-bound packets are routed by connection channel. */
1235                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1236                 chan = &conn->channels[channel];
1237
1238                 /* Ignore really old calls */
1239                 if (sp->hdr.callNumber < chan->last_call)
1240                         goto discard_unlock;
1241
1242                 if (sp->hdr.callNumber == chan->last_call) {
1243                         /* For the previous service call, if completed successfully, we
1244                          * discard all further packets.
1245                          */
1246                         if (rxrpc_conn_is_service(conn) &&
1247                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
1248                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
1249                                 goto discard_unlock;
1250
1251                         /* But otherwise we need to retransmit the final packet from
1252                          * data cached in the connection record.
1253                          */
1254                         rxrpc_post_packet_to_conn(conn, skb);
1255                         goto out_unlock;
1256                 }
1257
1258                 call = rcu_dereference(chan->call);
1259
1260                 if (sp->hdr.callNumber > chan->call_id) {
1261                         if (!(sp->hdr.flags & RXRPC_CLIENT_INITIATED)) {
1262                                 rcu_read_unlock();
1263                                 goto reject_packet;
1264                         }
1265                         if (call)
1266                                 rxrpc_input_implicit_end_call(conn, call);
1267                         call = NULL;
1268                 }
1269
1270                 if (call && sp->hdr.serviceId != call->service_id)
1271                         call->service_id = sp->hdr.serviceId;
1272         } else {
1273                 skew = 0;
1274                 call = NULL;
1275         }
1276
1277         if (!call || atomic_read(&call->usage) == 0) {
1278                 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
1279                     sp->hdr.callNumber == 0 ||
1280                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1281                         goto bad_message_unlock;
1282                 if (sp->hdr.seq != 1)
1283                         goto discard_unlock;
1284                 call = rxrpc_new_incoming_call(local, conn, skb);
1285                 if (!call) {
1286                         rcu_read_unlock();
1287                         goto reject_packet;
1288                 }
1289                 rxrpc_send_ping(call, skb, skew);
1290                 mutex_unlock(&call->user_mutex);
1291         }
1292
1293         rxrpc_input_call_packet(call, skb, skew);
1294         goto discard_unlock;
1295
1296 discard_unlock:
1297         rcu_read_unlock();
1298 discard:
1299         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1300 out:
1301         trace_rxrpc_rx_done(0, 0);
1302         return;
1303
1304 out_unlock:
1305         rcu_read_unlock();
1306         goto out;
1307
1308 wrong_security:
1309         rcu_read_unlock();
1310         trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1311                           RXKADINCONSISTENCY, EBADMSG);
1312         skb->priority = RXKADINCONSISTENCY;
1313         goto post_abort;
1314
1315 reupgrade:
1316         rcu_read_unlock();
1317         trace_rxrpc_abort("UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1318                           RX_PROTOCOL_ERROR, EBADMSG);
1319         goto protocol_error;
1320
1321 bad_message_unlock:
1322         rcu_read_unlock();
1323 bad_message:
1324         trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1325                           RX_PROTOCOL_ERROR, EBADMSG);
1326 protocol_error:
1327         skb->priority = RX_PROTOCOL_ERROR;
1328 post_abort:
1329         skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
1330 reject_packet:
1331         trace_rxrpc_rx_done(skb->mark, skb->priority);
1332         rxrpc_reject_packet(local, skb);
1333         _leave(" [badmsg]");
1334 }