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         rxrpc_seq_t top = READ_ONCE(call->tx_top);
 322
 323         if (call->ackr_reason) {
 324                 spin_lock_bh(&call->lock);
 325                 call->ackr_reason = 0;
 326                 call->resend_at = call->expire_at;
 327                 call->ack_at = call->expire_at;
 328                 spin_unlock_bh(&call->lock);
 329                 rxrpc_set_timer(call, rxrpc_timer_init_for_reply,
 330                                 ktime_get_real());
 331         }
 332
 333         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 334                 rxrpc_rotate_tx_window(call, top, &summary);
 335         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 336                 rxrpc_proto_abort("TXL", call, top);
 337                 return false;
 338         }
 339         if (!rxrpc_end_tx_phase(call, true, "ETD"))
 340                 return false;
 341         call->tx_phase = false;
 342         return true;
 343 }
 344
 345 /*
 346  * Scan a jumbo packet to validate its structure and to work out how many
 347  * subpackets it contains.
 348  *
 349  * A jumbo packet is a collection of consecutive packets glued together with
 350  * little headers between that indicate how to change the initial header for
 351  * each subpacket.
 352  *
 353  * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 354  * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 355  * size.
 356  */
 357 static bool rxrpc_validate_jumbo(struct sk_buff *skb)
 358 {
 359         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 360         unsigned int offset = sizeof(struct rxrpc_wire_header);
 361         unsigned int len = skb->len;
 362         int nr_jumbo = 1;
 363         u8 flags = sp->hdr.flags;
 364
 365         do {
 366                 nr_jumbo++;
 367                 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 368                         goto protocol_error;
 369                 if (flags & RXRPC_LAST_PACKET)
 370                         goto protocol_error;
 371                 offset += RXRPC_JUMBO_DATALEN;
 372                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 373                         goto protocol_error;
 374                 offset += sizeof(struct rxrpc_jumbo_header);
 375         } while (flags & RXRPC_JUMBO_PACKET);
 376
 377         sp->nr_jumbo = nr_jumbo;
 378         return true;
 379
 380 protocol_error:
 381         return false;
 382 }
 383
 384 /*
 385  * Handle reception of a duplicate packet.
 386  *
 387  * We have to take care to avoid an attack here whereby we're given a series of
 388  * jumbograms, each with a sequence number one before the preceding one and
 389  * filled up to maximum UDP size.  If they never send us the first packet in
 390  * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 391  * space until the call times out.
 392  *
 393  * We limit the space usage by only accepting three duplicate jumbo packets per
 394  * call.  After that, we tell the other side we're no longer accepting jumbos
 395  * (that information is encoded in the ACK packet).
 396  */
 397 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 398                                  u8 annotation, bool *_jumbo_bad)
 399 {
 400         /* Discard normal packets that are duplicates. */
 401         if (annotation == 0)
 402                 return;
 403
 404         /* Skip jumbo subpackets that are duplicates.  When we've had three or
 405          * more partially duplicate jumbo packets, we refuse to take any more
 406          * jumbos for this call.
 407          */
 408         if (!*_jumbo_bad) {
 409                 call->nr_jumbo_bad++;
 410                 *_jumbo_bad = true;
 411         }
 412 }
 413
 414 /*
 415  * Process a DATA packet, adding the packet to the Rx ring.
 416  */
 417 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
 418                              u16 skew)
 419 {
 420         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 421         enum rxrpc_call_state state;
 422         unsigned int offset = sizeof(struct rxrpc_wire_header);
 423         unsigned int ix;
 424         rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
 425         rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
 426         bool immediate_ack = false, jumbo_bad = false, queued;
 427         u16 len;
 428         u8 ack = 0, flags, annotation = 0;
 429
 430         _enter("{%u,%u},{%u,%u}",
 431                call->rx_hard_ack, call->rx_top, skb->len, seq);
 432
 433         _proto("Rx DATA %%%u { #%u f=%02x }",
 434                sp->hdr.serial, seq, sp->hdr.flags);
 435
 436         state = READ_ONCE(call->state);
 437         if (state >= RXRPC_CALL_COMPLETE)
 438                 return;
 439
 440         /* Received data implicitly ACKs all of the request packets we sent
 441          * when we're acting as a client.
 442          */
 443         if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 444              state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 445             !rxrpc_receiving_reply(call))
 446                 return;
 447
 448         call->ackr_prev_seq = seq;
 449
 450         hard_ack = READ_ONCE(call->rx_hard_ack);
 451         if (after(seq, hard_ack + call->rx_winsize)) {
 452                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 453                 ack_serial = serial;
 454                 goto ack;
 455         }
 456
 457         flags = sp->hdr.flags;
 458         if (flags & RXRPC_JUMBO_PACKET) {
 459                 if (call->nr_jumbo_bad > 3) {
 460                         ack = RXRPC_ACK_NOSPACE;
 461                         ack_serial = serial;
 462                         goto ack;
 463                 }
 464                 annotation = 1;
 465         }
 466
 467 next_subpacket:
 468         queued = false;
 469         ix = seq & RXRPC_RXTX_BUFF_MASK;
 470         len = skb->len;
 471         if (flags & RXRPC_JUMBO_PACKET)
 472                 len = RXRPC_JUMBO_DATALEN;
 473
 474         if (flags & RXRPC_LAST_PACKET) {
 475                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 476                     seq != call->rx_top)
 477                         return rxrpc_proto_abort("LSN", call, seq);
 478         } else {
 479                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 480                     after_eq(seq, call->rx_top))
 481                         return rxrpc_proto_abort("LSA", call, seq);
 482         }
 483
 484         trace_rxrpc_rx_data(call, seq, serial, flags, annotation);
 485         if (before_eq(seq, hard_ack)) {
 486                 ack = RXRPC_ACK_DUPLICATE;
 487                 ack_serial = serial;
 488                 goto skip;
 489         }
 490
 491         if (flags & RXRPC_REQUEST_ACK && !ack) {
 492                 ack = RXRPC_ACK_REQUESTED;
 493                 ack_serial = serial;
 494         }
 495
 496         if (call->rxtx_buffer[ix]) {
 497                 rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
 498                 if (ack != RXRPC_ACK_DUPLICATE) {
 499                         ack = RXRPC_ACK_DUPLICATE;
 500                         ack_serial = serial;
 501                 }
 502                 immediate_ack = true;
 503                 goto skip;
 504         }
 505
 506         /* Queue the packet.  We use a couple of memory barriers here as need
 507          * to make sure that rx_top is perceived to be set after the buffer
 508          * pointer and that the buffer pointer is set after the annotation and
 509          * the skb data.
 510          *
 511          * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 512          * and also rxrpc_fill_out_ack().
 513          */
 514         rxrpc_get_skb(skb, rxrpc_skb_rx_got);
 515         call->rxtx_annotations[ix] = annotation;
 516         smp_wmb();
 517         call->rxtx_buffer[ix] = skb;
 518         if (after(seq, call->rx_top)) {
 519                 smp_store_release(&call->rx_top, seq);
 520         } else if (before(seq, call->rx_top)) {
 521                 /* Send an immediate ACK if we fill in a hole */
 522                 if (!ack) {
 523                         ack = RXRPC_ACK_DELAY;
 524                         ack_serial = serial;
 525                 }
 526                 immediate_ack = true;
 527         }
 528         if (flags & RXRPC_LAST_PACKET) {
 529                 set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 530                 trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 531         } else {
 532                 trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 533         }
 534         queued = true;
 535
 536         if (after_eq(seq, call->rx_expect_next)) {
 537                 if (after(seq, call->rx_expect_next)) {
 538                         _net("OOS %u > %u", seq, call->rx_expect_next);
 539                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 540                         ack_serial = serial;
 541                 }
 542                 call->rx_expect_next = seq + 1;
 543         }
 544
 545 skip:
 546         offset += len;
 547         if (flags & RXRPC_JUMBO_PACKET) {
 548                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 549                         return rxrpc_proto_abort("XJF", call, seq);
 550                 offset += sizeof(struct rxrpc_jumbo_header);
 551                 seq++;
 552                 serial++;
 553                 annotation++;
 554                 if (flags & RXRPC_JUMBO_PACKET)
 555                         annotation |= RXRPC_RX_ANNO_JLAST;
 556                 if (after(seq, hard_ack + call->rx_winsize)) {
 557                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
 558                         ack_serial = serial;
 559                         if (!jumbo_bad) {
 560                                 call->nr_jumbo_bad++;
 561                                 jumbo_bad = true;
 562                         }
 563                         goto ack;
 564                 }
 565
 566                 _proto("Rx DATA Jumbo %%%u", serial);
 567                 goto next_subpacket;
 568         }
 569
 570         if (queued && flags & RXRPC_LAST_PACKET && !ack) {
 571                 ack = RXRPC_ACK_DELAY;
 572                 ack_serial = serial;
 573         }
 574
 575 ack:
 576         if (ack)
 577                 rxrpc_propose_ACK(call, ack, skew, ack_serial,
 578                                   immediate_ack, true,
 579                                   rxrpc_propose_ack_input_data);
 580
 581         if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1)
 582                 rxrpc_notify_socket(call);
 583         _leave(" [queued]");
 584 }
 585
 586 /*
 587  * Process a requested ACK.
 588  */
 589 static void rxrpc_input_requested_ack(struct rxrpc_call *call,
 590                                       ktime_t resp_time,
 591                                       rxrpc_serial_t orig_serial,
 592                                       rxrpc_serial_t ack_serial)
 593 {
 594         struct rxrpc_skb_priv *sp;
 595         struct sk_buff *skb;
 596         ktime_t sent_at;
 597         int ix;
 598
 599         for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
 600                 skb = call->rxtx_buffer[ix];
 601                 if (!skb)
 602                         continue;
 603
 604                 sp = rxrpc_skb(skb);
 605                 if (sp->hdr.serial != orig_serial)
 606                         continue;
 607                 smp_rmb();
 608                 sent_at = skb->tstamp;
 609                 goto found;
 610         }
 611         return;
 612
 613 found:
 614         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
 615                            orig_serial, ack_serial, sent_at, resp_time);
 616 }
 617
 618 /*
 619  * Process a ping response.
 620  */
 621 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 622                                       ktime_t resp_time,
 623                                       rxrpc_serial_t orig_serial,
 624                                       rxrpc_serial_t ack_serial)
 625 {
 626         rxrpc_serial_t ping_serial;
 627         ktime_t ping_time;
 628
 629         ping_time = call->ping_time;
 630         smp_rmb();
 631         ping_serial = call->ping_serial;
 632
 633         if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
 634             before(orig_serial, ping_serial))
 635                 return;
 636         clear_bit(RXRPC_CALL_PINGING, &call->flags);
 637         if (after(orig_serial, ping_serial))
 638                 return;
 639
 640         rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
 641                            orig_serial, ack_serial, ping_time, resp_time);
 642 }
 643
 644 /*
 645  * Process the extra information that may be appended to an ACK packet
 646  */
 647 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 648                                 struct rxrpc_ackinfo *ackinfo)
 649 {
 650         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 651         struct rxrpc_peer *peer;
 652         unsigned int mtu;
 653         bool wake = false;
 654         u32 rwind = ntohl(ackinfo->rwind);
 655
 656         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 657                sp->hdr.serial,
 658                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 659                rwind, ntohl(ackinfo->jumbo_max));
 660
 661         if (call->tx_winsize != rwind) {
 662                 if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 663                         rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 664                 if (rwind > call->tx_winsize)
 665                         wake = true;
 666                 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial,
 667                                             ntohl(ackinfo->rwind), wake);
 668                 call->tx_winsize = rwind;
 669         }
 670
 671         if (call->cong_ssthresh > rwind)
 672                 call->cong_ssthresh = rwind;
 673
 674         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 675
 676         peer = call->peer;
 677         if (mtu < peer->maxdata) {
 678                 spin_lock_bh(&peer->lock);
 679                 peer->maxdata = mtu;
 680                 peer->mtu = mtu + peer->hdrsize;
 681                 spin_unlock_bh(&peer->lock);
 682                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 683         }
 684
 685         if (wake)
 686                 wake_up(&call->waitq);
 687 }
 688
 689 /*
 690  * Process individual soft ACKs.
 691  *
 692  * Each ACK in the array corresponds to one packet and can be either an ACK or
 693  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 694  * packets that lie beyond the end of the ACK list are scheduled for resend by
 695  * the timer on the basis that the peer might just not have processed them at
 696  * the time the ACK was sent.
 697  */
 698 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 699                                   rxrpc_seq_t seq, int nr_acks,
 700                                   struct rxrpc_ack_summary *summary)
 701 {
 702         int ix;
 703         u8 annotation, anno_type;
 704
 705         for (; nr_acks > 0; nr_acks--, seq++) {
 706                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 707                 annotation = call->rxtx_annotations[ix];
 708                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 709                 annotation &= ~RXRPC_TX_ANNO_MASK;
 710                 switch (*acks++) {
 711                 case RXRPC_ACK_TYPE_ACK:
 712                         summary->nr_acks++;
 713                         if (anno_type == RXRPC_TX_ANNO_ACK)
 714                                 continue;
 715                         summary->nr_new_acks++;
 716                         call->rxtx_annotations[ix] =
 717                                 RXRPC_TX_ANNO_ACK | annotation;
 718                         break;
 719                 case RXRPC_ACK_TYPE_NACK:
 720                         if (!summary->nr_nacks &&
 721                             call->acks_lowest_nak != seq) {
 722                                 call->acks_lowest_nak = seq;
 723                                 summary->new_low_nack = true;
 724                         }
 725                         summary->nr_nacks++;
 726                         if (anno_type == RXRPC_TX_ANNO_NAK)
 727                                 continue;
 728                         summary->nr_new_nacks++;
 729                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
 730                                 continue;
 731                         call->rxtx_annotations[ix] =
 732                                 RXRPC_TX_ANNO_NAK | annotation;
 733                         break;
 734                 default:
 735                         return rxrpc_proto_abort("SFT", call, 0);
 736                 }
 737         }
 738 }
 739
 740 /*
 741  * Process an ACK packet.
 742  *
 743  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 744  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 745  *
 746  * A hard-ACK means that a packet has been processed and may be discarded; a
 747  * soft-ACK means that the packet may be discarded and retransmission
 748  * requested.  A phase is complete when all packets are hard-ACK'd.
 749  */
 750 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 751                             u16 skew)
 752 {
 753         struct rxrpc_ack_summary summary = { 0 };
 754         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 755         union {
 756                 struct rxrpc_ackpacket ack;
 757                 struct rxrpc_ackinfo info;
 758                 u8 acks[RXRPC_MAXACKS];
 759         } buf;
 760         rxrpc_serial_t acked_serial;
 761         rxrpc_seq_t first_soft_ack, hard_ack;
 762         int nr_acks, offset, ioffset;
 763
 764         _enter("");
 765
 766         offset = sizeof(struct rxrpc_wire_header);
 767         if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
 768                 _debug("extraction failure");
 769                 return rxrpc_proto_abort("XAK", call, 0);
 770         }
 771         offset += sizeof(buf.ack);
 772
 773         acked_serial = ntohl(buf.ack.serial);
 774         first_soft_ack = ntohl(buf.ack.firstPacket);
 775         hard_ack = first_soft_ack - 1;
 776         nr_acks = buf.ack.nAcks;
 777         summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 778                               buf.ack.reason : RXRPC_ACK__INVALID);
 779
 780         trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial,
 781                            first_soft_ack, ntohl(buf.ack.previousPacket),
 782                            summary.ack_reason, nr_acks);
 783
 784         if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
 785                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 786                                           sp->hdr.serial);
 787         if (buf.ack.reason == RXRPC_ACK_REQUESTED)
 788                 rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
 789                                           sp->hdr.serial);
 790
 791         if (buf.ack.reason == RXRPC_ACK_PING) {
 792                 _proto("Rx ACK %%%u PING Request", sp->hdr.serial);
 793                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 794                                   skew, sp->hdr.serial, true, true,
 795                                   rxrpc_propose_ack_respond_to_ping);
 796         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 797                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 798                                   skew, sp->hdr.serial, true, true,
 799                                   rxrpc_propose_ack_respond_to_ack);
 800         }
 801
 802         ioffset = offset + nr_acks + 3;
 803         if (skb->len >= ioffset + sizeof(buf.info)) {
 804                 if (skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
 805                         return rxrpc_proto_abort("XAI", call, 0);
 806                 rxrpc_input_ackinfo(call, skb, &buf.info);
 807         }
 808
 809         if (first_soft_ack == 0)
 810                 return rxrpc_proto_abort("AK0", call, 0);
 811
 812         /* Ignore ACKs unless we are or have just been transmitting. */
 813         switch (READ_ONCE(call->state)) {
 814         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 815         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 816         case RXRPC_CALL_SERVER_SEND_REPLY:
 817         case RXRPC_CALL_SERVER_AWAIT_ACK:
 818                 break;
 819         default:
 820                 return;
 821         }
 822
 823         /* Discard any out-of-order or duplicate ACKs. */
 824         if (before_eq(sp->hdr.serial, call->acks_latest)) {
 825                 _debug("discard ACK %d <= %d",
 826                        sp->hdr.serial, call->acks_latest);
 827                 return;
 828         }
 829         call->acks_latest_ts = skb->tstamp;
 830         call->acks_latest = sp->hdr.serial;
 831
 832         if (before(hard_ack, call->tx_hard_ack) ||
 833             after(hard_ack, call->tx_top))
 834                 return rxrpc_proto_abort("AKW", call, 0);
 835         if (nr_acks > call->tx_top - hard_ack)
 836                 return rxrpc_proto_abort("AKN", call, 0);
 837
 838         if (after(hard_ack, call->tx_hard_ack))
 839                 rxrpc_rotate_tx_window(call, hard_ack, &summary);
 840
 841         if (nr_acks > 0) {
 842                 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0)
 843                         return rxrpc_proto_abort("XSA", call, 0);
 844                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
 845                                       &summary);
 846         }
 847
 848         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 849                 rxrpc_end_tx_phase(call, false, "ETA");
 850                 return;
 851         }
 852
 853         if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
 854             RXRPC_TX_ANNO_LAST &&
 855             summary.nr_acks == call->tx_top - hard_ack &&
 856             rxrpc_is_client_call(call))
 857                 rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
 858                                   false, true,
 859                                   rxrpc_propose_ack_ping_for_lost_reply);
 860
 861         return rxrpc_congestion_management(call, skb, &summary, acked_serial);
 862 }
 863
 864 /*
 865  * Process an ACKALL packet.
 866  */
 867 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 868 {
 869         struct rxrpc_ack_summary summary = { 0 };
 870         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 871
 872         _proto("Rx ACKALL %%%u", sp->hdr.serial);
 873
 874         rxrpc_rotate_tx_window(call, call->tx_top, &summary);
 875         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 876                 rxrpc_end_tx_phase(call, false, "ETL");
 877 }
 878
 879 /*
 880  * Process an ABORT packet directed at a call.
 881  */
 882 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 883 {
 884         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 885         __be32 wtmp;
 886         u32 abort_code = RX_CALL_DEAD;
 887
 888         _enter("");
 889
 890         if (skb->len >= 4 &&
 891             skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
 892                           &wtmp, sizeof(wtmp)) >= 0)
 893                 abort_code = ntohl(wtmp);
 894
 895         trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
 896
 897         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 898
 899         if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 900                                       abort_code, -ECONNABORTED))
 901                 rxrpc_notify_socket(call);
 902 }
 903
 904 /*
 905  * Process an incoming call packet.
 906  */
 907 static void rxrpc_input_call_packet(struct rxrpc_call *call,
 908                                     struct sk_buff *skb, u16 skew)
 909 {
 910         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 911
 912         _enter("%p,%p", call, skb);
 913
 914         switch (sp->hdr.type) {
 915         case RXRPC_PACKET_TYPE_DATA:
 916                 rxrpc_input_data(call, skb, skew);
 917                 break;
 918
 919         case RXRPC_PACKET_TYPE_ACK:
 920                 rxrpc_input_ack(call, skb, skew);
 921                 break;
 922
 923         case RXRPC_PACKET_TYPE_BUSY:
 924                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 925
 926                 /* Just ignore BUSY packets from the server; the retry and
 927                  * lifespan timers will take care of business.  BUSY packets
 928                  * from the client don't make sense.
 929                  */
 930                 break;
 931
 932         case RXRPC_PACKET_TYPE_ABORT:
 933                 rxrpc_input_abort(call, skb);
 934                 break;
 935
 936         case RXRPC_PACKET_TYPE_ACKALL:
 937                 rxrpc_input_ackall(call, skb);
 938                 break;
 939
 940         default:
 941                 break;
 942         }
 943
 944         _leave("");
 945 }
 946
 947 /*
 948  * Handle a new call on a channel implicitly completing the preceding call on
 949  * that channel.
 950  *
 951  * TODO: If callNumber > call_id + 1, renegotiate security.
 952  */
 953 static void rxrpc_input_implicit_end_call(struct rxrpc_connection *conn,
 954                                           struct rxrpc_call *call)
 955 {
 956         switch (READ_ONCE(call->state)) {
 957         case RXRPC_CALL_SERVER_AWAIT_ACK:
 958                 rxrpc_call_completed(call);
 959                 break;
 960         case RXRPC_CALL_COMPLETE:
 961                 break;
 962         default:
 963                 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
 964                         set_bit(RXRPC_CALL_EV_ABORT, &call->events);
 965                         rxrpc_queue_call(call);
 966                 }
 967                 break;
 968         }
 969
 970         trace_rxrpc_improper_term(call);
 971         __rxrpc_disconnect_call(conn, call);
 972         rxrpc_notify_socket(call);
 973 }
 974
 975 /*
 976  * post connection-level events to the connection
 977  * - this includes challenges, responses, some aborts and call terminal packet
 978  *   retransmission.
 979  */
 980 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 981                                       struct sk_buff *skb)
 982 {
 983         _enter("%p,%p", conn, skb);
 984
 985         skb_queue_tail(&conn->rx_queue, skb);
 986         rxrpc_queue_conn(conn);
 987 }
 988
 989 /*
 990  * post endpoint-level events to the local endpoint
 991  * - this includes debug and version messages
 992  */
 993 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 994                                        struct sk_buff *skb)
 995 {
 996         _enter("%p,%p", local, skb);
 997
 998         skb_queue_tail(&local->event_queue, skb);
 999         rxrpc_queue_local(local);
1000 }
1001
1002 /*
1003  * put a packet up for transport-level abort
1004  */
1005 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1006 {
1007         CHECK_SLAB_OKAY(&local->usage);
1008
1009         skb_queue_tail(&local->reject_queue, skb);
1010         rxrpc_queue_local(local);
1011 }
1012
1013 /*
1014  * Extract the wire header from a packet and translate the byte order.
1015  */
1016 static noinline
1017 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1018 {
1019         struct rxrpc_wire_header whdr;
1020
1021         /* dig out the RxRPC connection details */
1022         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1023                 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1024                                       tracepoint_string("bad_hdr"));
1025                 return -EBADMSG;
1026         }
1027
1028         memset(sp, 0, sizeof(*sp));
1029         sp->hdr.epoch           = ntohl(whdr.epoch);
1030         sp->hdr.cid             = ntohl(whdr.cid);
1031         sp->hdr.callNumber      = ntohl(whdr.callNumber);
1032         sp->hdr.seq             = ntohl(whdr.seq);
1033         sp->hdr.serial          = ntohl(whdr.serial);
1034         sp->hdr.flags           = whdr.flags;
1035         sp->hdr.type            = whdr.type;
1036         sp->hdr.userStatus      = whdr.userStatus;
1037         sp->hdr.securityIndex   = whdr.securityIndex;
1038         sp->hdr._rsvd           = ntohs(whdr._rsvd);
1039         sp->hdr.serviceId       = ntohs(whdr.serviceId);
1040         return 0;
1041 }
1042
1043 /*
1044  * handle data received on the local endpoint
1045  * - may be called in interrupt context
1046  *
1047  * The socket is locked by the caller and this prevents the socket from being
1048  * shut down and the local endpoint from going away, thus sk_user_data will not
1049  * be cleared until this function returns.
1050  */
1051 void rxrpc_data_ready(struct sock *udp_sk)
1052 {
1053         struct rxrpc_connection *conn;
1054         struct rxrpc_channel *chan;
1055         struct rxrpc_call *call;
1056         struct rxrpc_skb_priv *sp;
1057         struct rxrpc_local *local = udp_sk->sk_user_data;
1058         struct sk_buff *skb;
1059         unsigned int channel;
1060         int ret, skew;
1061
1062         _enter("%p", udp_sk);
1063
1064         ASSERT(!irqs_disabled());
1065
1066         skb = skb_recv_udp(udp_sk, 0, 1, &ret);
1067         if (!skb) {
1068                 if (ret == -EAGAIN)
1069                         return;
1070                 _debug("UDP socket error %d", ret);
1071                 return;
1072         }
1073
1074         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
1075
1076         _net("recv skb %p", skb);
1077
1078         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
1079         if (skb_checksum_complete(skb)) {
1080                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1081                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
1082                 _leave(" [CSUM failed]");
1083                 return;
1084         }
1085
1086         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
1087
1088         /* The UDP protocol already released all skb resources;
1089          * we are free to add our own data there.
1090          */
1091         sp = rxrpc_skb(skb);
1092
1093         /* dig out the RxRPC connection details */
1094         if (rxrpc_extract_header(sp, skb) < 0)
1095                 goto bad_message;
1096
1097         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1098                 static int lose;
1099                 if ((lose++ & 7) == 7) {
1100                         trace_rxrpc_rx_lose(sp);
1101                         rxrpc_lose_skb(skb, rxrpc_skb_rx_lost);
1102                         return;
1103                 }
1104         }
1105
1106         trace_rxrpc_rx_packet(sp);
1107
1108         _net("Rx RxRPC %s ep=%x call=%x:%x",
1109              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
1110              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
1111
1112         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
1113             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
1114                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
1115                 goto bad_message;
1116         }
1117
1118         switch (sp->hdr.type) {
1119         case RXRPC_PACKET_TYPE_VERSION:
1120                 rxrpc_post_packet_to_local(local, skb);
1121                 goto out;
1122
1123         case RXRPC_PACKET_TYPE_BUSY:
1124                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
1125                         goto discard;
1126                 /* Fall through */
1127
1128         case RXRPC_PACKET_TYPE_DATA:
1129                 if (sp->hdr.callNumber == 0)
1130                         goto bad_message;
1131                 if (sp->hdr.flags & RXRPC_JUMBO_PACKET &&
1132                     !rxrpc_validate_jumbo(skb))
1133                         goto bad_message;
1134                 break;
1135         }
1136
1137         rcu_read_lock();
1138
1139         conn = rxrpc_find_connection_rcu(local, skb);
1140         if (conn) {
1141                 if (sp->hdr.securityIndex != conn->security_ix)
1142                         goto wrong_security;
1143
1144                 if (sp->hdr.serviceId != conn->service_id) {
1145                         if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) ||
1146                             conn->service_id != conn->params.service_id)
1147                                 goto reupgrade;
1148                         conn->service_id = sp->hdr.serviceId;
1149                 }
1150
1151                 if (sp->hdr.callNumber == 0) {
1152                         /* Connection-level packet */
1153                         _debug("CONN %p {%d}", conn, conn->debug_id);
1154                         rxrpc_post_packet_to_conn(conn, skb);
1155                         goto out_unlock;
1156                 }
1157
1158                 /* Note the serial number skew here */
1159                 skew = (int)sp->hdr.serial - (int)conn->hi_serial;
1160                 if (skew >= 0) {
1161                         if (skew > 0)
1162                                 conn->hi_serial = sp->hdr.serial;
1163                 } else {
1164                         skew = -skew;
1165                         skew = min(skew, 65535);
1166                 }
1167
1168                 /* Call-bound packets are routed by connection channel. */
1169                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1170                 chan = &conn->channels[channel];
1171
1172                 /* Ignore really old calls */
1173                 if (sp->hdr.callNumber < chan->last_call)
1174                         goto discard_unlock;
1175
1176                 if (sp->hdr.callNumber == chan->last_call) {
1177                         /* For the previous service call, if completed successfully, we
1178                          * discard all further packets.
1179                          */
1180                         if (rxrpc_conn_is_service(conn) &&
1181                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
1182                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
1183                                 goto discard_unlock;
1184
1185                         /* But otherwise we need to retransmit the final packet from
1186                          * data cached in the connection record.
1187                          */
1188                         rxrpc_post_packet_to_conn(conn, skb);
1189                         goto out_unlock;
1190                 }
1191
1192                 call = rcu_dereference(chan->call);
1193
1194                 if (sp->hdr.callNumber > chan->call_id) {
1195                         if (!(sp->hdr.flags & RXRPC_CLIENT_INITIATED)) {
1196                                 rcu_read_unlock();
1197                                 goto reject_packet;
1198                         }
1199                         if (call)
1200                                 rxrpc_input_implicit_end_call(conn, call);
1201                         call = NULL;
1202                 }
1203
1204                 if (call && sp->hdr.serviceId != call->service_id)
1205                         call->service_id = sp->hdr.serviceId;
1206         } else {
1207                 skew = 0;
1208                 call = NULL;
1209         }
1210
1211         if (!call || atomic_read(&call->usage) == 0) {
1212                 if (!(sp->hdr.type & RXRPC_CLIENT_INITIATED) ||
1213                     sp->hdr.callNumber == 0 ||
1214                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1215                         goto bad_message_unlock;
1216                 if (sp->hdr.seq != 1)
1217                         goto discard_unlock;
1218                 call = rxrpc_new_incoming_call(local, conn, skb);
1219                 if (!call) {
1220                         rcu_read_unlock();
1221                         goto reject_packet;
1222                 }
1223                 rxrpc_send_ping(call, skb, skew);
1224                 mutex_unlock(&call->user_mutex);
1225         }
1226
1227         rxrpc_input_call_packet(call, skb, skew);
1228         goto discard_unlock;
1229
1230 discard_unlock:
1231         rcu_read_unlock();
1232 discard:
1233         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
1234 out:
1235         trace_rxrpc_rx_done(0, 0);
1236         return;
1237
1238 out_unlock:
1239         rcu_read_unlock();
1240         goto out;
1241
1242 wrong_security:
1243         rcu_read_unlock();
1244         trace_rxrpc_abort("SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1245                           RXKADINCONSISTENCY, EBADMSG);
1246         skb->priority = RXKADINCONSISTENCY;
1247         goto post_abort;
1248
1249 reupgrade:
1250         rcu_read_unlock();
1251         trace_rxrpc_abort("UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1252                           RX_PROTOCOL_ERROR, EBADMSG);
1253         goto protocol_error;
1254
1255 bad_message_unlock:
1256         rcu_read_unlock();
1257 bad_message:
1258         trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1259                           RX_PROTOCOL_ERROR, EBADMSG);
1260 protocol_error:
1261         skb->priority = RX_PROTOCOL_ERROR;
1262 post_abort:
1263         skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
1264 reject_packet:
1265         trace_rxrpc_rx_done(skb->mark, skb->priority);
1266         rxrpc_reject_packet(local, skb);
1267         _leave(" [badmsg]");
1268 }