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->debug_id, 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         else
 596                 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, skew, serial,
 597                                   false, true,
 598                                   rxrpc_propose_ack_input_data);
 599
 600         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1) {
 601                 trace_rxrpc_notify_socket(call->debug_id, serial);
 602                 rxrpc_notify_socket(call);
 603         }
 604         _leave(" [queued]");
 605 }
 606
 607 /*
 608  * Process a requested ACK.
 609  */
 610 static void rxrpc_input_requested_ack(struct rxrpc_call *call,
 611                                       ktime_t resp_time,
 612                                       rxrpc_serial_t orig_serial,
 613                                       rxrpc_serial_t ack_serial)
 614 {
 615         struct rxrpc_skb_priv *sp;
 616         struct sk_buff *skb;
 617         ktime_t sent_at;
 618         int ix;
 619
 620         for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
 621                 skb = call->rxtx_buffer[ix];
 622                 if (!skb)
 623                         continue;
 624
 625                 sp = rxrpc_skb(skb);
 626                 if (sp->hdr.serial != orig_serial)
 627                         continue;
 628                 smp_rmb();
 629                 sent_at = skb->tstamp;
 630                 goto found;
 631         }
 632         return;
 633
 634 found:
 635         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
 636                            orig_serial, ack_serial, sent_at, resp_time);
 637 }
 638
 639 /*
 640  * Process the response to a ping that we sent to find out if we lost an ACK.
 641  *
 642  * If we got back a ping response that indicates a lower tx_top than what we
 643  * had at the time of the ping transmission, we adjudge all the DATA packets
 644  * sent between the response tx_top and the ping-time tx_top to have been lost.
 645  */
 646 static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
 647 {
 648         rxrpc_seq_t top, bottom, seq;
 649         bool resend = false;
 650
 651         spin_lock_bh(&call->lock);
 652
 653         bottom = call->tx_hard_ack + 1;
 654         top = call->acks_lost_top;
 655         if (before(bottom, top)) {
 656                 for (seq = bottom; before_eq(seq, top); seq++) {
 657                         int ix = seq & RXRPC_RXTX_BUFF_MASK;
 658                         u8 annotation = call->rxtx_annotations[ix];
 659                         u8 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 660
 661                         if (anno_type != RXRPC_TX_ANNO_UNACK)
 662                                 continue;
 663                         annotation &= ~RXRPC_TX_ANNO_MASK;
 664                         annotation |= RXRPC_TX_ANNO_RETRANS;
 665                         call->rxtx_annotations[ix] = annotation;
 666                         resend = true;
 667                 }
 668         }
 669
 670         spin_unlock_bh(&call->lock);
 671
 672         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 673                 rxrpc_queue_call(call);
 674 }
 675
 676 /*
 677  * Process a ping response.
 678  */
 679 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 680                                       ktime_t resp_time,
 681                                       rxrpc_serial_t orig_serial,
 682                                       rxrpc_serial_t ack_serial)
 683 {
 684         rxrpc_serial_t ping_serial;
 685         ktime_t ping_time;
 686
 687         ping_time = call->ping_time;
 688         smp_rmb();
 689         ping_serial = call->ping_serial;
 690
 691         if (orig_serial == call->acks_lost_ping)
 692                 rxrpc_input_check_for_lost_ack(call);
 693
 694         if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
 695             before(orig_serial, ping_serial))
 696                 return;
 697         clear_bit(RXRPC_CALL_PINGING, &call->flags);
 698         if (after(orig_serial, ping_serial))
 699                 return;
 700
 701         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
 702                            orig_serial, ack_serial, ping_time, resp_time);
 703 }
 704
 705 /*
 706  * Process the extra information that may be appended to an ACK packet
 707  */
 708 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 709                                 struct rxrpc_ackinfo *ackinfo)
 710 {
 711         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 712         struct rxrpc_peer *peer;
 713         unsigned int mtu;
 714         bool wake = false;
 715         u32 rwind = ntohl(ackinfo->rwind);
 716
 717         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 718                sp->hdr.serial,
 719                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 720                rwind, ntohl(ackinfo->jumbo_max));
 721
 722         if (call->tx_winsize != rwind) {
 723                 if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 724                         rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 725                 if (rwind > call->tx_winsize)
 726                         wake = true;
 727                 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial,
 728                                             ntohl(ackinfo->rwind), wake);
 729                 call->tx_winsize = rwind;
 730         }
 731
 732         if (call->cong_ssthresh > rwind)
 733                 call->cong_ssthresh = rwind;
 734
 735         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 736
 737         peer = call->peer;
 738         if (mtu < peer->maxdata) {
 739                 spin_lock_bh(&peer->lock);
 740                 peer->maxdata = mtu;
 741                 peer->mtu = mtu + peer->hdrsize;
 742                 spin_unlock_bh(&peer->lock);
 743                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 744         }
 745
 746         if (wake)
 747                 wake_up(&call->waitq);
 748 }
 749
 750 /*
 751  * Process individual soft ACKs.
 752  *
 753  * Each ACK in the array corresponds to one packet and can be either an ACK or
 754  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 755  * packets that lie beyond the end of the ACK list are scheduled for resend by
 756  * the timer on the basis that the peer might just not have processed them at
 757  * the time the ACK was sent.
 758  */
 759 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 760                                   rxrpc_seq_t seq, int nr_acks,
 761                                   struct rxrpc_ack_summary *summary)
 762 {
 763         int ix;
 764         u8 annotation, anno_type;
 765
 766         for (; nr_acks > 0; nr_acks--, seq++) {
 767                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 768                 annotation = call->rxtx_annotations[ix];
 769                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 770                 annotation &= ~RXRPC_TX_ANNO_MASK;
 771                 switch (*acks++) {
 772                 case RXRPC_ACK_TYPE_ACK:
 773                         summary->nr_acks++;
 774                         if (anno_type == RXRPC_TX_ANNO_ACK)
 775                                 continue;
 776                         summary->nr_new_acks++;
 777                         call->rxtx_annotations[ix] =
 778                                 RXRPC_TX_ANNO_ACK | annotation;
 779                         break;
 780                 case RXRPC_ACK_TYPE_NACK:
 781                         if (!summary->nr_nacks &&
 782                             call->acks_lowest_nak != seq) {
 783                                 call->acks_lowest_nak = seq;
 784                                 summary->new_low_nack = true;
 785                         }
 786                         summary->nr_nacks++;
 787                         if (anno_type == RXRPC_TX_ANNO_NAK)
 788                                 continue;
 789                         summary->nr_new_nacks++;
 790                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
 791                                 continue;
 792                         call->rxtx_annotations[ix] =
 793                                 RXRPC_TX_ANNO_NAK | annotation;
 794                         break;
 795                 default:
 796                         return rxrpc_proto_abort("SFT", call, 0);
 797                 }
 798         }
 799 }
 800
 801 /*
 802  * Process an ACK packet.
 803  *
 804  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 805  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 806  *
 807  * A hard-ACK means that a packet has been processed and may be discarded; a
 808  * soft-ACK means that the packet may be discarded and retransmission
 809  * requested.  A phase is complete when all packets are hard-ACK'd.
 810  */
 811 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 812                             u16 skew)
 813 {
 814         struct rxrpc_ack_summary summary = { 0 };
 815         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 816         union {
 817                 struct rxrpc_ackpacket ack;
 818                 struct rxrpc_ackinfo info;
 819                 u8 acks[RXRPC_MAXACKS];
 820         } buf;
 821         rxrpc_serial_t acked_serial;
 822         rxrpc_seq_t first_soft_ack, hard_ack;
 823         int nr_acks, offset, ioffset;
 824
 825         _enter("");
 826
 827         offset = sizeof(struct rxrpc_wire_header);
 828         if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
 829                 _debug("extraction failure");
 830                 return rxrpc_proto_abort("XAK", call, 0);
 831         }
 832         offset += sizeof(buf.ack);
 833
 834         acked_serial = ntohl(buf.ack.serial);
 835         first_soft_ack = ntohl(buf.ack.firstPacket);
 836         hard_ack = first_soft_ack - 1;
 837         nr_acks = buf.ack.nAcks;
 838         summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 839                               buf.ack.reason : RXRPC_ACK__INVALID);
 840
 841         trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial,
 842                            first_soft_ack, ntohl(buf.ack.previousPacket),
 843                            summary.ack_reason, nr_acks);
 844
 845         if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
 846                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 847                                           sp->hdr.serial);
 848         if (buf.ack.reason == RXRPC_ACK_REQUESTED)
 849                 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
 850                                           sp->hdr.serial);
 851
 852         if (buf.ack.reason == RXRPC_ACK_PING) {
 853                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 854                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 855                                   skew, sp->hdr.serial, true, true,
 856                                   rxrpc_propose_ack_respond_to_ping);
 857         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 858                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 859                                   skew, sp->hdr.serial, true, true,
 860                                   rxrpc_propose_ack_respond_to_ack);
 861         }
 862
 863         ioffset = offset + nr_acks + 3;
 864         if (skb->len >= ioffset + sizeof(buf.info)) {
 865                 if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
 866                         return rxrpc_proto_abort("XAI", call, 0);
 867                 rxrpc_input_ackinfo(call, skb, &buf.info);
 868         }
 869
 870         if (first_soft_ack == 0)
 871                 return rxrpc_proto_abort("AK0", call, 0);
 872
 873         /* Ignore ACKs unless we are or have just been transmitting. */
 874         switch (READ_ONCE(call->state)) {
 875         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 876         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 877         case RXRPC_CALL_SERVER_SEND_REPLY:
 878         case RXRPC_CALL_SERVER_AWAIT_ACK:
 879                 break;
 880         default:
 881                 return;
 882         }
 883
 884         /* Discard any out-of-order or duplicate ACKs. */
 885         if (before_eq(sp->hdr.serial, call->acks_latest)) {
 886                 _debug("discard ACK %d <= %d",
 887                        sp->hdr.serial, call->acks_latest);
 888                 return;
 889         }
 890         call->acks_latest_ts = skb->tstamp;
 891         call->acks_latest = sp->hdr.serial;
 892
 893         if (before(hard_ack, call->tx_hard_ack) ||
 894             after(hard_ack, call->tx_top))
 895                 return rxrpc_proto_abort("AKW", call, 0);
 896         if (nr_acks > call->tx_top - hard_ack)
 897                 return rxrpc_proto_abort("AKN", call, 0);
 898
 899         if (after(hard_ack, call->tx_hard_ack))
 900                 rxrpc_rotate_tx_window(call, hard_ack, &summary);
 901
 902         if (nr_acks > 0) {
 903                 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0)
 904                         return rxrpc_proto_abort("XSA", call, 0);
 905                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
 906                                       &summary);
 907         }
 908
 909         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 910                 rxrpc_end_tx_phase(call, false, "ETA");
 911                 return;
 912         }
 913
 914         if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
 915             RXRPC_TX_ANNO_LAST &&
 916             summary.nr_acks == call->tx_top - hard_ack &&
 917             rxrpc_is_client_call(call))
 918                 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
 919                                   false, true,
 920                                   rxrpc_propose_ack_ping_for_lost_reply);
 921
 922         return rxrpc_congestion_management(call, skb, &summary, acked_serial);
 923 }
 924
 925 /*
 926  * Process an ACKALL packet.
 927  */
 928 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 929 {
 930         struct rxrpc_ack_summary summary = { 0 };
 931         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 932
 933         _proto("Rx ACKALL %%%u", sp->hdr.serial);
 934
 935         rxrpc_rotate_tx_window(call, call->tx_top, &summary);
 936         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 937                 rxrpc_end_tx_phase(call, false, "ETL");
 938 }
 939
 940 /*
 941  * Process an ABORT packet directed at a call.
 942  */
 943 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 944 {
 945         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 946         __be32 wtmp;
 947         u32 abort_code = RX_CALL_DEAD;
 948
 949         _enter("");
 950
 951         if (skb->len >= 4 &&
 952             skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
 953                           &wtmp, sizeof(wtmp)) >= 0)
 954                 abort_code = ntohl(wtmp);
 955
 956         trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
 957
 958         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 959
 960         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 961                                       abort_code, -ECONNABORTED))
 962                 rxrpc_notify_socket(call);
 963 }
 964
 965 /*
 966  * Process an incoming call packet.
 967  */
 968 static void rxrpc_input_call_packet(struct rxrpc_call *call,
 969                                     struct sk_buff *skb, u16 skew)
 970 {
 971         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 972         unsigned long timo;
 973
 974         _enter("%p,%p", call, skb);
 975
 976         timo = READ_ONCE(call->next_rx_timo);
 977         if (timo) {
 978                 unsigned long now = jiffies, expect_rx_by;
 979
 980                 expect_rx_by = now + timo;
 981                 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
 982                 rxrpc_reduce_call_timer(call, expect_rx_by, now,
 983                                         rxrpc_timer_set_for_normal);
 984         }
 985
 986         switch (sp->hdr.type) {
 987         case RXRPC_PACKET_TYPE_DATA:
 988                 rxrpc_input_data(call, skb, skew);
 989                 break;
 990
 991         case RXRPC_PACKET_TYPE_ACK:
 992                 rxrpc_input_ack(call, skb, skew);
 993                 break;
 994
 995         case RXRPC_PACKET_TYPE_BUSY:
 996                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 997
 998                 /* Just ignore BUSY packets from the server; the retry and
 999                  * lifespan timers will take care of business.  BUSY packets
1000                  * from the client don't make sense.
1001                  */
1002                 break;
1003
1004         case RXRPC_PACKET_TYPE_ABORT:
1005                 rxrpc_input_abort(call, skb);
1006                 break;
1007
1008         case RXRPC_PACKET_TYPE_ACKALL:
1009                 rxrpc_input_ackall(call, skb);
1010                 break;
1011
1012         default:
1013                 break;
1014         }
1015
1016         _leave("");
1017 }
1018
1019 /*
1020  * Handle a new call on a channel implicitly completing the preceding call on
1021  * that channel.
1022  *
1023  * TODO: If callNumber > call_id + 1, renegotiate security.
1024  */
1025 static void rxrpc_input_implicit_end_call(struct rxrpc_connection *conn,
1026                                           struct rxrpc_call *call)
1027 {
1028         switch (READ_ONCE(call->state)) {
1029         case RXRPC_CALL_SERVER_AWAIT_ACK:
1030                 rxrpc_call_completed(call);
1031                 break;
1032         case RXRPC_CALL_COMPLETE:
1033                 break;
1034         default:
1035                 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
1036                         set_bit(RXRPC_CALL_EV_ABORT, &call->events);
1037                         rxrpc_queue_call(call);
1038                 }
1039                 break;
1040         }
1041
1042         trace_rxrpc_improper_term(call);
1043         __rxrpc_disconnect_call(conn, call);
1044         rxrpc_notify_socket(call);
1045 }
1046
1047 /*
1048  * post connection-level events to the connection
1049  * - this includes challenges, responses, some aborts and call terminal packet
1050  *   retransmission.
1051  */
1052 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
1053                                       struct sk_buff *skb)
1054 {
1055         _enter("%p,%p", conn, skb);
1056
1057         skb_queue_tail(&conn->rx_queue, skb);
1058         rxrpc_queue_conn(conn);
1059 }
1060
1061 /*
1062  * post endpoint-level events to the local endpoint
1063  * - this includes debug and version messages
1064  */
1065 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
1066                                        struct sk_buff *skb)
1067 {
1068         _enter("%p,%p", local, skb);
1069
1070         skb_queue_tail(&local->event_queue, skb);
1071         rxrpc_queue_local(local);
1072 }
1073
1074 /*
1075  * put a packet up for transport-level abort
1076  */
1077 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1078 {
1079         CHECK_SLAB_OKAY(&local->usage);
1080
1081         skb_queue_tail(&local->reject_queue, skb);
1082         rxrpc_queue_local(local);
1083 }
1084
1085 /*
1086  * Extract the wire header from a packet and translate the byte order.
1087  */
1088 static noinline
1089 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1090 {
1091         struct rxrpc_wire_header whdr;
1092
1093         /* dig out the RxRPC connection details */
1094         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1095                 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1096                                       tracepoint_string("bad_hdr"));
1097                 return -EBADMSG;
1098         }
1099
1100         memset(sp, 0, sizeof(*sp));
1101         sp->hdr.epoch           = ntohl(whdr.epoch);
1102         sp->hdr.cid             = ntohl(whdr.cid);
1103         sp->hdr.callNumber      = ntohl(whdr.callNumber);
1104         sp->hdr.seq             = ntohl(whdr.seq);
1105         sp->hdr.serial          = ntohl(whdr.serial);
1106         sp->hdr.flags           = whdr.flags;
1107         sp->hdr.type            = whdr.type;
1108         sp->hdr.userStatus      = whdr.userStatus;
1109         sp->hdr.securityIndex   = whdr.securityIndex;
1110         sp->hdr._rsvd           = ntohs(whdr._rsvd);
1111         sp->hdr.serviceId       = ntohs(whdr.serviceId);
1112         return 0;
1113 }
1114
1115 /*
1116  * handle data received on the local endpoint
1117  * - may be called in interrupt context
1118  *
1119  * The socket is locked by the caller and this prevents the socket from being
1120  * shut down and the local endpoint from going away, thus sk_user_data will not
1121  * be cleared until this function returns.
1122  */
1123 void rxrpc_data_ready(struct sock *udp_sk)
1124 {
1125         struct rxrpc_connection *conn;
1126         struct rxrpc_channel *chan;
1127         struct rxrpc_call *call;
1128         struct rxrpc_skb_priv *sp;
1129         struct rxrpc_local *local = udp_sk->sk_user_data;
1130         struct sk_buff *skb;
1131         unsigned int channel;
1132         int ret, skew;
1133
1134         _enter("%p", udp_sk);
1135
1136         ASSERT(!irqs_disabled());
1137
1138         skb = skb_recv_udp(udp_sk, 0, 1, &ret);
1139         if (!skb) {
1140                 if (ret == -EAGAIN)
1141                         return;
1142                 _debug("UDP socket error %d", ret);
1143                 return;
1144         }
1145
1146         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
1147
1148         _net("recv skb %p", skb);
1149
1150         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
1151         if (skb_checksum_complete(skb)) {
1152                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1153                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
1154                 _leave(" [CSUM failed]");
1155                 return;
1156         }
1157
1158         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
1159
1160         /* The UDP protocol already released all skb resources;
1161          * we are free to add our own data there.
1162          */
1163         sp = rxrpc_skb(skb);
1164
1165         /* dig out the RxRPC connection details */
1166         if (rxrpc_extract_header(sp, skb) < 0)
1167                 goto bad_message;
1168
1169         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1170                 static int lose;
1171                 if ((lose++ & 7) == 7) {
1172                         trace_rxrpc_rx_lose(sp);
1173                         rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
1174                         return;
1175                 }
1176         }
1177
1178         trace_rxrpc_rx_packet(sp);
1179
1180         _net("Rx RxRPC %s ep=%x call=%x:%x",
1181              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
1182              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
1183
1184         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
1185             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
1186                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
1187                 goto bad_message;
1188         }
1189
1190         switch (sp->hdr.type) {
1191         case RXRPC_PACKET_TYPE_VERSION:
1192                 if (!(sp->hdr.flags & RXRPC_CLIENT_INITIATED))
1193                         goto discard;
1194                 rxrpc_post_packet_to_local(local, skb);
1195                 goto out;
1196
1197         case RXRPC_PACKET_TYPE_BUSY:
1198                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
1199                         goto discard;
1200                 /* Fall through */
1201
1202         case RXRPC_PACKET_TYPE_DATA:
1203                 if (sp->hdr.callNumber == 0)
1204                         goto bad_message;
1205                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
1206                     !rxrpc_validate_jumbo(skb))
1207                         goto bad_message;
1208                 break;
1209
1210                 /* Packet types 9-11 should just be ignored. */
1211         case RXRPC_PACKET_TYPE_PARAMS:
1212         case RXRPC_PACKET_TYPE_10:
1213         case RXRPC_PACKET_TYPE_11:
1214                 goto discard;
1215         }
1216
1217         rcu_read_lock();
1218
1219         conn = rxrpc_find_connection_rcu(local, skb);
1220         if (conn) {
1221                 if (sp->hdr.securityIndex != conn->security_ix)
1222                         goto wrong_security;
1223
1224                 if (sp->hdr.serviceId != conn->service_id) {
1225                         if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) ||
1226                             conn->service_id != conn->params.service_id)
1227                                 goto reupgrade;
1228                         conn->service_id = sp->hdr.serviceId;
1229                 }
1230
1231                 if (sp->hdr.callNumber == 0) {
1232                         /* Connection-level packet */
1233                         _debug("CONN %p {%d}", conn, conn->debug_id);
1234                         rxrpc_post_packet_to_conn(conn, skb);
1235                         goto out_unlock;
1236                 }
1237
1238                 /* Note the serial number skew here */
1239                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
1240                 if (skew >= 0) {
1241                         if (skew > 0)
1242                                 conn->hi_serial = sp->hdr.serial;
1243                 } else {
1244                         skew = -skew;
1245                         skew = min(skew, 65535);
1246                 }
1247
1248                 /* Call-bound packets are routed by connection channel. */
1249                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1250                 chan = &conn->channels[channel];
1251
1252                 /* Ignore really old calls */
1253                 if (sp->hdr.callNumber < chan->last_call)
1254                         goto discard_unlock;
1255
1256                 if (sp->hdr.callNumber == chan->last_call) {
1257                         if (chan->call ||
1258                             sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
1259                                 goto discard_unlock;
1260
1261                         /* For the previous service call, if completed
1262                          * successfully, we discard all further packets.
1263                          */
1264                         if (rxrpc_conn_is_service(conn) &&
1265                             chan->last_type == RXRPC_PACKET_TYPE_ACK)
1266                                 goto discard_unlock;
1267
1268                         /* But otherwise we need to retransmit the final packet
1269                          * from data cached in the connection record.
1270                          */
1271                         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
1272                                 trace_rxrpc_rx_data(chan->call_debug_id,
1273                                                     sp->hdr.seq,
1274                                                     sp->hdr.serial,
1275                                                     sp->hdr.flags, 0);
1276                         rxrpc_post_packet_to_conn(conn, skb);
1277                         goto out_unlock;
1278                 }
1279
1280                 call = rcu_dereference(chan->call);
1281
1282                 if (sp->hdr.callNumber > chan->call_id) {
1283                         if (!(sp->hdr.flags & RXRPC_CLIENT_INITIATED)) {
1284                                 rcu_read_unlock();
1285                                 goto reject_packet;
1286                         }
1287                         if (call)
1288                                 rxrpc_input_implicit_end_call(conn, call);
1289                         call = NULL;
1290                 }
1291
1292                 if (call) {
1293                         if (sp->hdr.serviceId != call->service_id)
1294                                 call->service_id = sp->hdr.serviceId;
1295                         if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
1296                                 call->rx_serial = sp->hdr.serial;
1297                         if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
1298                                 set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
1299                 }
1300         } else {
1301                 skew = 0;
1302                 call = NULL;
1303         }
1304
1305         if (!call || atomic_read(&call->usage) == 0) {
1306                 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
1307                     sp->hdr.callNumber == 0 ||
1308                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1309                         goto bad_message_unlock;
1310                 if (sp->hdr.seq != 1)
1311                         goto discard_unlock;
1312                 call = rxrpc_new_incoming_call(local, conn, skb);
1313                 if (!call) {
1314                         rcu_read_unlock();
1315                         goto reject_packet;
1316                 }
1317                 rxrpc_send_ping(call, skb, skew);
1318                 mutex_unlock(&call->user_mutex);
1319         }
1320
1321         rxrpc_input_call_packet(call, skb, skew);
1322         goto discard_unlock;
1323
1324 discard_unlock:
1325         rcu_read_unlock();
1326 discard:
1327         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1328 out:
1329         trace_rxrpc_rx_done(0, 0);
1330         return;
1331
1332 out_unlock:
1333         rcu_read_unlock();
1334         goto out;
1335
1336 wrong_security:
1337         rcu_read_unlock();
1338         trace_rxrpc_abort(0, "SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1339                           RXKADINCONSISTENCY, EBADMSG);
1340         skb->priority = RXKADINCONSISTENCY;
1341         goto post_abort;
1342
1343 reupgrade:
1344         rcu_read_unlock();
1345         trace_rxrpc_abort(0, "UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1346                           RX_PROTOCOL_ERROR, EBADMSG);
1347         goto protocol_error;
1348
1349 bad_message_unlock:
1350         rcu_read_unlock();
1351 bad_message:
1352         trace_rxrpc_abort(0, "BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1353                           RX_PROTOCOL_ERROR, EBADMSG);
1354 protocol_error:
1355         skb->priority = RX_PROTOCOL_ERROR;
1356 post_abort:
1357         skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
1358 reject_packet:
1359         trace_rxrpc_rx_done(skb->mark, skb->priority);
1360         rxrpc_reject_packet(local, skb);
1361         _leave(" [badmsg]");
1362 }