net/rxrpc/input.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* RxRPC packet reception
   3  *
   4  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/module.h>
  11 #include <linux/net.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/errqueue.h>
  14 #include <linux/udp.h>
  15 #include <linux/in.h>
  16 #include <linux/in6.h>
  17 #include <linux/icmp.h>
  18 #include <linux/gfp.h>
  19 #include <net/sock.h>
  20 #include <net/af_rxrpc.h>
  21 #include <net/ip.h>
  22 #include <net/udp.h>
  23 #include <net/net_namespace.h>
  24 #include "ar-internal.h"
  25
  26 static void rxrpc_proto_abort(const char *why,
  27                               struct rxrpc_call *call, rxrpc_seq_t seq)
  28 {
  29         if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) {
  30                 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
  31                 rxrpc_queue_call(call);
  32         }
  33 }
  34
  35 /*
  36  * Do TCP-style congestion management [RFC 5681].
  37  */
  38 static void rxrpc_congestion_management(struct rxrpc_call *call,
  39                                         struct sk_buff *skb,
  40                                         struct rxrpc_ack_summary *summary,
  41                                         rxrpc_serial_t acked_serial)
  42 {
  43         enum rxrpc_congest_change change = rxrpc_cong_no_change;
  44         unsigned int cumulative_acks = call->cong_cumul_acks;
  45         unsigned int cwnd = call->cong_cwnd;
  46         bool resend = false;
  47
  48         summary->flight_size =
  49                 (call->tx_top - call->tx_hard_ack) - summary->nr_acks;
  50
  51         if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
  52                 summary->retrans_timeo = true;
  53                 call->cong_ssthresh = max_t(unsigned int,
  54                                             summary->flight_size / 2, 2);
  55                 cwnd = 1;
  56                 if (cwnd >= call->cong_ssthresh &&
  57                     call->cong_mode == RXRPC_CALL_SLOW_START) {
  58                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  59                         call->cong_tstamp = skb->tstamp;
  60                         cumulative_acks = 0;
  61                 }
  62         }
  63
  64         cumulative_acks += summary->nr_new_acks;
  65         cumulative_acks += summary->nr_rot_new_acks;
  66         if (cumulative_acks > 255)
  67                 cumulative_acks = 255;
  68
  69         summary->mode = call->cong_mode;
  70         summary->cwnd = call->cong_cwnd;
  71         summary->ssthresh = call->cong_ssthresh;
  72         summary->cumulative_acks = cumulative_acks;
  73         summary->dup_acks = call->cong_dup_acks;
  74
  75         switch (call->cong_mode) {
  76         case RXRPC_CALL_SLOW_START:
  77                 if (summary->nr_nacks > 0)
  78                         goto packet_loss_detected;
  79                 if (summary->cumulative_acks > 0)
  80                         cwnd += 1;
  81                 if (cwnd >= call->cong_ssthresh) {
  82                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  83                         call->cong_tstamp = skb->tstamp;
  84                 }
  85                 goto out;
  86
  87         case RXRPC_CALL_CONGEST_AVOIDANCE:
  88                 if (summary->nr_nacks > 0)
  89                         goto packet_loss_detected;
  90
  91                 /* We analyse the number of packets that get ACK'd per RTT
  92                  * period and increase the window if we managed to fill it.
  93                  */
  94                 if (call->peer->rtt_count == 0)
  95                         goto out;
  96                 if (ktime_before(skb->tstamp,
  97                                  ktime_add_us(call->cong_tstamp,
  98                                               call->peer->srtt_us >> 3)))
  99                         goto out_no_clear_ca;
 100                 change = rxrpc_cong_rtt_window_end;
 101                 call->cong_tstamp = skb->tstamp;
 102                 if (cumulative_acks >= cwnd)
 103                         cwnd++;
 104                 goto out;
 105
 106         case RXRPC_CALL_PACKET_LOSS:
 107                 if (summary->nr_nacks == 0)
 108                         goto resume_normality;
 109
 110                 if (summary->new_low_nack) {
 111                         change = rxrpc_cong_new_low_nack;
 112                         call->cong_dup_acks = 1;
 113                         if (call->cong_extra > 1)
 114                                 call->cong_extra = 1;
 115                         goto send_extra_data;
 116                 }
 117
 118                 call->cong_dup_acks++;
 119                 if (call->cong_dup_acks < 3)
 120                         goto send_extra_data;
 121
 122                 change = rxrpc_cong_begin_retransmission;
 123                 call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
 124                 call->cong_ssthresh = max_t(unsigned int,
 125                                             summary->flight_size / 2, 2);
 126                 cwnd = call->cong_ssthresh + 3;
 127                 call->cong_extra = 0;
 128                 call->cong_dup_acks = 0;
 129                 resend = true;
 130                 goto out;
 131
 132         case RXRPC_CALL_FAST_RETRANSMIT:
 133                 if (!summary->new_low_nack) {
 134                         if (summary->nr_new_acks == 0)
 135                                 cwnd += 1;
 136                         call->cong_dup_acks++;
 137                         if (call->cong_dup_acks == 2) {
 138                                 change = rxrpc_cong_retransmit_again;
 139                                 call->cong_dup_acks = 0;
 140                                 resend = true;
 141                         }
 142                 } else {
 143                         change = rxrpc_cong_progress;
 144                         cwnd = call->cong_ssthresh;
 145                         if (summary->nr_nacks == 0)
 146                                 goto resume_normality;
 147                 }
 148                 goto out;
 149
 150         default:
 151                 BUG();
 152                 goto out;
 153         }
 154
 155 resume_normality:
 156         change = rxrpc_cong_cleared_nacks;
 157         call->cong_dup_acks = 0;
 158         call->cong_extra = 0;
 159         call->cong_tstamp = skb->tstamp;
 160         if (cwnd < call->cong_ssthresh)
 161                 call->cong_mode = RXRPC_CALL_SLOW_START;
 162         else
 163                 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
 164 out:
 165         cumulative_acks = 0;
 166 out_no_clear_ca:
 167         if (cwnd >= RXRPC_RXTX_BUFF_SIZE - 1)
 168                 cwnd = RXRPC_RXTX_BUFF_SIZE - 1;
 169         call->cong_cwnd = cwnd;
 170         call->cong_cumul_acks = cumulative_acks;
 171         trace_rxrpc_congest(call, summary, acked_serial, change);
 172         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 173                 rxrpc_queue_call(call);
 174         return;
 175
 176 packet_loss_detected:
 177         change = rxrpc_cong_saw_nack;
 178         call->cong_mode = RXRPC_CALL_PACKET_LOSS;
 179         call->cong_dup_acks = 0;
 180         goto send_extra_data;
 181
 182 send_extra_data:
 183         /* Send some previously unsent DATA if we have some to advance the ACK
 184          * state.
 185          */
 186         if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
 187             RXRPC_TX_ANNO_LAST ||
 188             summary->nr_acks != call->tx_top - call->tx_hard_ack) {
 189                 call->cong_extra++;
 190                 wake_up(&call->waitq);
 191         }
 192         goto out_no_clear_ca;
 193 }
 194
 195 /*
 196  * Apply a hard ACK by advancing the Tx window.
 197  */
 198 static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 199                                    struct rxrpc_ack_summary *summary)
 200 {
 201         struct sk_buff *skb, *list = NULL;
 202         bool rot_last = false;
 203         int ix;
 204         u8 annotation;
 205
 206         if (call->acks_lowest_nak == call->tx_hard_ack) {
 207                 call->acks_lowest_nak = to;
 208         } else if (before_eq(call->acks_lowest_nak, to)) {
 209                 summary->new_low_nack = true;
 210                 call->acks_lowest_nak = to;
 211         }
 212
 213         spin_lock(&call->lock);
 214
 215         while (before(call->tx_hard_ack, to)) {
 216                 call->tx_hard_ack++;
 217                 ix = call->tx_hard_ack & RXRPC_RXTX_BUFF_MASK;
 218                 skb = call->rxtx_buffer[ix];
 219                 annotation = call->rxtx_annotations[ix];
 220                 rxrpc_see_skb(skb, rxrpc_skb_rotated);
 221                 call->rxtx_buffer[ix] = NULL;
 222                 call->rxtx_annotations[ix] = 0;
 223                 skb->next = list;
 224                 list = skb;
 225
 226                 if (annotation & RXRPC_TX_ANNO_LAST) {
 227                         set_bit(RXRPC_CALL_TX_LAST, &call->flags);
 228                         rot_last = true;
 229                 }
 230                 if ((annotation & RXRPC_TX_ANNO_MASK) != RXRPC_TX_ANNO_ACK)
 231                         summary->nr_rot_new_acks++;
 232         }
 233
 234         spin_unlock(&call->lock);
 235
 236         trace_rxrpc_transmit(call, (rot_last ?
 237                                     rxrpc_transmit_rotate_last :
 238                                     rxrpc_transmit_rotate));
 239         wake_up(&call->waitq);
 240
 241         while (list) {
 242                 skb = list;
 243                 list = skb->next;
 244                 skb_mark_not_on_list(skb);
 245                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 246         }
 247
 248         return rot_last;
 249 }
 250
 251 /*
 252  * End the transmission phase of a call.
 253  *
 254  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 255  * or a final ACK packet.
 256  */
 257 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 258                                const char *abort_why)
 259 {
 260         unsigned int state;
 261
 262         ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 263
 264         write_lock(&call->state_lock);
 265
 266         state = call->state;
 267         switch (state) {
 268         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 269         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 270                 if (reply_begun)
 271                         call->state = state = RXRPC_CALL_CLIENT_RECV_REPLY;
 272                 else
 273                         call->state = state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 274                 break;
 275
 276         case RXRPC_CALL_SERVER_AWAIT_ACK:
 277                 __rxrpc_call_completed(call);
 278                 state = call->state;
 279                 break;
 280
 281         default:
 282                 goto bad_state;
 283         }
 284
 285         write_unlock(&call->state_lock);
 286         if (state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 287                 trace_rxrpc_transmit(call, rxrpc_transmit_await_reply);
 288         else
 289                 trace_rxrpc_transmit(call, rxrpc_transmit_end);
 290         _leave(" = ok");
 291         return true;
 292
 293 bad_state:
 294         write_unlock(&call->state_lock);
 295         kdebug("end_tx %s", rxrpc_call_states[call->state]);
 296         rxrpc_proto_abort(abort_why, call, call->tx_top);
 297         return false;
 298 }
 299
 300 /*
 301  * Begin the reply reception phase of a call.
 302  */
 303 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 304 {
 305         struct rxrpc_ack_summary summary = { 0 };
 306         unsigned long now, timo;
 307         rxrpc_seq_t top = READ_ONCE(call->tx_top);
 308
 309         if (call->ackr_reason) {
 310                 spin_lock_bh(&call->lock);
 311                 call->ackr_reason = 0;
 312                 spin_unlock_bh(&call->lock);
 313                 now = jiffies;
 314                 timo = now + MAX_JIFFY_OFFSET;
 315                 WRITE_ONCE(call->resend_at, timo);
 316                 WRITE_ONCE(call->ack_at, timo);
 317                 trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
 318         }
 319
 320         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 321                 if (!rxrpc_rotate_tx_window(call, top, &summary)) {
 322                         rxrpc_proto_abort("TXL", call, top);
 323                         return false;
 324                 }
 325         }
 326         if (!rxrpc_end_tx_phase(call, true, "ETD"))
 327                 return false;
 328         call->tx_phase = false;
 329         return true;
 330 }
 331
 332 /*
 333  * Scan a data packet to validate its structure and to work out how many
 334  * subpackets it contains.
 335  *
 336  * A jumbo packet is a collection of consecutive packets glued together with
 337  * little headers between that indicate how to change the initial header for
 338  * each subpacket.
 339  *
 340  * RXRPC_JUMBO_PACKET must be set on all but the last subpacket - and all but
 341  * the last are RXRPC_JUMBO_DATALEN in size.  The last subpacket may be of any
 342  * size.
 343  */
 344 static bool rxrpc_validate_data(struct sk_buff *skb)
 345 {
 346         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 347         unsigned int offset = sizeof(struct rxrpc_wire_header);
 348         unsigned int len = skb->len;
 349         u8 flags = sp->hdr.flags;
 350
 351         for (;;) {
 352                 if (flags & RXRPC_REQUEST_ACK)
 353                         __set_bit(sp->nr_subpackets, sp->rx_req_ack);
 354                 sp->nr_subpackets++;
 355
 356                 if (!(flags & RXRPC_JUMBO_PACKET))
 357                         break;
 358
 359                 if (len - offset < RXRPC_JUMBO_SUBPKTLEN)
 360                         goto protocol_error;
 361                 if (flags & RXRPC_LAST_PACKET)
 362                         goto protocol_error;
 363                 offset += RXRPC_JUMBO_DATALEN;
 364                 if (skb_copy_bits(skb, offset, &flags, 1) < 0)
 365                         goto protocol_error;
 366                 offset += sizeof(struct rxrpc_jumbo_header);
 367         }
 368
 369         if (flags & RXRPC_LAST_PACKET)
 370                 sp->rx_flags |= RXRPC_SKB_INCL_LAST;
 371         return true;
 372
 373 protocol_error:
 374         return false;
 375 }
 376
 377 /*
 378  * Handle reception of a duplicate packet.
 379  *
 380  * We have to take care to avoid an attack here whereby we're given a series of
 381  * jumbograms, each with a sequence number one before the preceding one and
 382  * filled up to maximum UDP size.  If they never send us the first packet in
 383  * the sequence, they can cause us to have to hold on to around 2MiB of kernel
 384  * space until the call times out.
 385  *
 386  * We limit the space usage by only accepting three duplicate jumbo packets per
 387  * call.  After that, we tell the other side we're no longer accepting jumbos
 388  * (that information is encoded in the ACK packet).
 389  */
 390 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 391                                  bool is_jumbo, bool *_jumbo_bad)
 392 {
 393         /* Discard normal packets that are duplicates. */
 394         if (is_jumbo)
 395                 return;
 396
 397         /* Skip jumbo subpackets that are duplicates.  When we've had three or
 398          * more partially duplicate jumbo packets, we refuse to take any more
 399          * jumbos for this call.
 400          */
 401         if (!*_jumbo_bad) {
 402                 call->nr_jumbo_bad++;
 403                 *_jumbo_bad = true;
 404         }
 405 }
 406
 407 /*
 408  * Process a DATA packet, adding the packet to the Rx ring.  The caller's
 409  * packet ref must be passed on or discarded.
 410  */
 411 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 412 {
 413         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 414         enum rxrpc_call_state state;
 415         unsigned int j, nr_subpackets, nr_unacked = 0;
 416         rxrpc_serial_t serial = sp->hdr.serial, ack_serial = serial;
 417         rxrpc_seq_t seq0 = sp->hdr.seq, hard_ack;
 418         bool immediate_ack = false, jumbo_bad = false;
 419         u8 ack = 0;
 420
 421         _enter("{%u,%u},{%u,%u}",
 422                call->rx_hard_ack, call->rx_top, skb->len, seq0);
 423
 424         _proto("Rx DATA %%%u { #%u f=%02x n=%u }",
 425                sp->hdr.serial, seq0, sp->hdr.flags, sp->nr_subpackets);
 426
 427         state = READ_ONCE(call->state);
 428         if (state >= RXRPC_CALL_COMPLETE) {
 429                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 430                 return;
 431         }
 432
 433         if (state == RXRPC_CALL_SERVER_RECV_REQUEST) {
 434                 unsigned long timo = READ_ONCE(call->next_req_timo);
 435                 unsigned long now, expect_req_by;
 436
 437                 if (timo) {
 438                         now = jiffies;
 439                         expect_req_by = now + timo;
 440                         WRITE_ONCE(call->expect_req_by, expect_req_by);
 441                         rxrpc_reduce_call_timer(call, expect_req_by, now,
 442                                                 rxrpc_timer_set_for_idle);
 443                 }
 444         }
 445
 446         spin_lock(&call->input_lock);
 447
 448         /* Received data implicitly ACKs all of the request packets we sent
 449          * when we're acting as a client.
 450          */
 451         if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 452              state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 453             !rxrpc_receiving_reply(call))
 454                 goto unlock;
 455
 456         hard_ack = READ_ONCE(call->rx_hard_ack);
 457
 458         nr_subpackets = sp->nr_subpackets;
 459         if (nr_subpackets > 1) {
 460                 if (call->nr_jumbo_bad > 3) {
 461                         ack = RXRPC_ACK_NOSPACE;
 462                         ack_serial = serial;
 463                         goto ack;
 464                 }
 465         }
 466
 467         for (j = 0; j < nr_subpackets; j++) {
 468                 rxrpc_serial_t serial = sp->hdr.serial + j;
 469                 rxrpc_seq_t seq = seq0 + j;
 470                 unsigned int ix = seq & RXRPC_RXTX_BUFF_MASK;
 471                 bool terminal = (j == nr_subpackets - 1);
 472                 bool last = terminal && (sp->rx_flags & RXRPC_SKB_INCL_LAST);
 473                 u8 flags, annotation = j;
 474
 475                 _proto("Rx DATA+%u %%%u { #%x t=%u l=%u }",
 476                      j, serial, seq, terminal, last);
 477
 478                 if (last) {
 479                         if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 480                             seq != call->rx_top) {
 481                                 rxrpc_proto_abort("LSN", call, seq);
 482                                 goto unlock;
 483                         }
 484                 } else {
 485                         if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 486                             after_eq(seq, call->rx_top)) {
 487                                 rxrpc_proto_abort("LSA", call, seq);
 488                                 goto unlock;
 489                         }
 490                 }
 491
 492                 flags = 0;
 493                 if (last)
 494                         flags |= RXRPC_LAST_PACKET;
 495                 if (!terminal)
 496                         flags |= RXRPC_JUMBO_PACKET;
 497                 if (test_bit(j, sp->rx_req_ack))
 498                         flags |= RXRPC_REQUEST_ACK;
 499                 trace_rxrpc_rx_data(call->debug_id, seq, serial, flags, annotation);
 500
 501                 if (before_eq(seq, hard_ack)) {
 502                         ack = RXRPC_ACK_DUPLICATE;
 503                         ack_serial = serial;
 504                         continue;
 505                 }
 506
 507                 if (call->rxtx_buffer[ix]) {
 508                         rxrpc_input_dup_data(call, seq, nr_subpackets > 1,
 509                                              &jumbo_bad);
 510                         if (ack != RXRPC_ACK_DUPLICATE) {
 511                                 ack = RXRPC_ACK_DUPLICATE;
 512                                 ack_serial = serial;
 513                         }
 514                         immediate_ack = true;
 515                         continue;
 516                 }
 517
 518                 if (after(seq, hard_ack + call->rx_winsize)) {
 519                         ack = RXRPC_ACK_EXCEEDS_WINDOW;
 520                         ack_serial = serial;
 521                         if (flags & RXRPC_JUMBO_PACKET) {
 522                                 if (!jumbo_bad) {
 523                                         call->nr_jumbo_bad++;
 524                                         jumbo_bad = true;
 525                                 }
 526                         }
 527
 528                         goto ack;
 529                 }
 530
 531                 if (flags & RXRPC_REQUEST_ACK && !ack) {
 532                         ack = RXRPC_ACK_REQUESTED;
 533                         ack_serial = serial;
 534                 }
 535
 536                 if (after(seq0, call->ackr_highest_seq))
 537                         call->ackr_highest_seq = seq0;
 538
 539                 /* Queue the packet.  We use a couple of memory barriers here as need
 540                  * to make sure that rx_top is perceived to be set after the buffer
 541                  * pointer and that the buffer pointer is set after the annotation and
 542                  * the skb data.
 543                  *
 544                  * Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
 545                  * and also rxrpc_fill_out_ack().
 546                  */
 547                 if (!terminal)
 548                         rxrpc_get_skb(skb, rxrpc_skb_got);
 549                 call->rxtx_annotations[ix] = annotation;
 550                 smp_wmb();
 551                 call->rxtx_buffer[ix] = skb;
 552                 if (after(seq, call->rx_top)) {
 553                         smp_store_release(&call->rx_top, seq);
 554                 } else if (before(seq, call->rx_top)) {
 555                         /* Send an immediate ACK if we fill in a hole */
 556                         if (!ack) {
 557                                 ack = RXRPC_ACK_DELAY;
 558                                 ack_serial = serial;
 559                         }
 560                         immediate_ack = true;
 561                 }
 562
 563                 if (terminal) {
 564                         /* From this point on, we're not allowed to touch the
 565                          * packet any longer as its ref now belongs to the Rx
 566                          * ring.
 567                          */
 568                         skb = NULL;
 569                         sp = NULL;
 570                 }
 571
 572                 nr_unacked++;
 573
 574                 if (last) {
 575                         set_bit(RXRPC_CALL_RX_LAST, &call->flags);
 576                         if (!ack) {
 577                                 ack = RXRPC_ACK_DELAY;
 578                                 ack_serial = serial;
 579                         }
 580                         trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
 581                 } else {
 582                         trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
 583                 }
 584
 585                 if (after_eq(seq, call->rx_expect_next)) {
 586                         if (after(seq, call->rx_expect_next)) {
 587                                 _net("OOS %u > %u", seq, call->rx_expect_next);
 588                                 ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 589                                 ack_serial = serial;
 590                         }
 591                         call->rx_expect_next = seq + 1;
 592                 }
 593                 if (!ack)
 594                         ack_serial = serial;
 595         }
 596
 597 ack:
 598         if (atomic_add_return(nr_unacked, &call->ackr_nr_unacked) > 2 && !ack)
 599                 ack = RXRPC_ACK_IDLE;
 600
 601         if (ack)
 602                 rxrpc_propose_ACK(call, ack, ack_serial,
 603                                   immediate_ack, true,
 604                                   rxrpc_propose_ack_input_data);
 605         else
 606                 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, serial,
 607                                   false, true,
 608                                   rxrpc_propose_ack_input_data);
 609
 610         trace_rxrpc_notify_socket(call->debug_id, serial);
 611         rxrpc_notify_socket(call);
 612
 613 unlock:
 614         spin_unlock(&call->input_lock);
 615         rxrpc_free_skb(skb, rxrpc_skb_freed);
 616         _leave(" [queued]");
 617 }
 618
 619 /*
 620  * See if there's a cached RTT probe to complete.
 621  */
 622 static void rxrpc_complete_rtt_probe(struct rxrpc_call *call,
 623                                      ktime_t resp_time,
 624                                      rxrpc_serial_t acked_serial,
 625                                      rxrpc_serial_t ack_serial,
 626                                      enum rxrpc_rtt_rx_trace type)
 627 {
 628         rxrpc_serial_t orig_serial;
 629         unsigned long avail;
 630         ktime_t sent_at;
 631         bool matched = false;
 632         int i;
 633
 634         avail = READ_ONCE(call->rtt_avail);
 635         smp_rmb(); /* Read avail bits before accessing data. */
 636
 637         for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) {
 638                 if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail))
 639                         continue;
 640
 641                 sent_at = call->rtt_sent_at[i];
 642                 orig_serial = call->rtt_serial[i];
 643
 644                 if (orig_serial == acked_serial) {
 645                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 646                         smp_mb(); /* Read data before setting avail bit */
 647                         set_bit(i, &call->rtt_avail);
 648                         if (type != rxrpc_rtt_rx_cancel)
 649                                 rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial,
 650                                                    sent_at, resp_time);
 651                         else
 652                                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_cancel, i,
 653                                                    orig_serial, acked_serial, 0, 0);
 654                         matched = true;
 655                 }
 656
 657                 /* If a later serial is being acked, then mark this slot as
 658                  * being available.
 659                  */
 660                 if (after(acked_serial, orig_serial)) {
 661                         trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i,
 662                                            orig_serial, acked_serial, 0, 0);
 663                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 664                         smp_wmb();
 665                         set_bit(i, &call->rtt_avail);
 666                 }
 667         }
 668
 669         if (!matched)
 670                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0);
 671 }
 672
 673 /*
 674  * Process the response to a ping that we sent to find out if we lost an ACK.
 675  *
 676  * If we got back a ping response that indicates a lower tx_top than what we
 677  * had at the time of the ping transmission, we adjudge all the DATA packets
 678  * sent between the response tx_top and the ping-time tx_top to have been lost.
 679  */
 680 static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
 681 {
 682         rxrpc_seq_t top, bottom, seq;
 683         bool resend = false;
 684
 685         spin_lock_bh(&call->lock);
 686
 687         bottom = call->tx_hard_ack + 1;
 688         top = call->acks_lost_top;
 689         if (before(bottom, top)) {
 690                 for (seq = bottom; before_eq(seq, top); seq++) {
 691                         int ix = seq & RXRPC_RXTX_BUFF_MASK;
 692                         u8 annotation = call->rxtx_annotations[ix];
 693                         u8 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 694
 695                         if (anno_type != RXRPC_TX_ANNO_UNACK)
 696                                 continue;
 697                         annotation &= ~RXRPC_TX_ANNO_MASK;
 698                         annotation |= RXRPC_TX_ANNO_RETRANS;
 699                         call->rxtx_annotations[ix] = annotation;
 700                         resend = true;
 701                 }
 702         }
 703
 704         spin_unlock_bh(&call->lock);
 705
 706         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 707                 rxrpc_queue_call(call);
 708 }
 709
 710 /*
 711  * Process a ping response.
 712  */
 713 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 714                                       ktime_t resp_time,
 715                                       rxrpc_serial_t acked_serial,
 716                                       rxrpc_serial_t ack_serial)
 717 {
 718         if (acked_serial == call->acks_lost_ping)
 719                 rxrpc_input_check_for_lost_ack(call);
 720 }
 721
 722 /*
 723  * Process the extra information that may be appended to an ACK packet
 724  */
 725 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 726                                 struct rxrpc_ackinfo *ackinfo)
 727 {
 728         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 729         struct rxrpc_peer *peer;
 730         unsigned int mtu;
 731         bool wake = false;
 732         u32 rwind = ntohl(ackinfo->rwind);
 733
 734         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 735                sp->hdr.serial,
 736                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 737                rwind, ntohl(ackinfo->jumbo_max));
 738
 739         if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 740                 rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 741         if (call->tx_winsize != rwind) {
 742                 if (rwind > call->tx_winsize)
 743                         wake = true;
 744                 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake);
 745                 call->tx_winsize = rwind;
 746         }
 747
 748         if (call->cong_ssthresh > rwind)
 749                 call->cong_ssthresh = rwind;
 750
 751         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 752
 753         peer = call->peer;
 754         if (mtu < peer->maxdata) {
 755                 spin_lock_bh(&peer->lock);
 756                 peer->maxdata = mtu;
 757                 peer->mtu = mtu + peer->hdrsize;
 758                 spin_unlock_bh(&peer->lock);
 759                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 760         }
 761
 762         if (wake)
 763                 wake_up(&call->waitq);
 764 }
 765
 766 /*
 767  * Process individual soft ACKs.
 768  *
 769  * Each ACK in the array corresponds to one packet and can be either an ACK or
 770  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 771  * packets that lie beyond the end of the ACK list are scheduled for resend by
 772  * the timer on the basis that the peer might just not have processed them at
 773  * the time the ACK was sent.
 774  */
 775 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 776                                   rxrpc_seq_t seq, int nr_acks,
 777                                   struct rxrpc_ack_summary *summary)
 778 {
 779         int ix;
 780         u8 annotation, anno_type;
 781
 782         for (; nr_acks > 0; nr_acks--, seq++) {
 783                 ix = seq & RXRPC_RXTX_BUFF_MASK;
 784                 annotation = call->rxtx_annotations[ix];
 785                 anno_type = annotation & RXRPC_TX_ANNO_MASK;
 786                 annotation &= ~RXRPC_TX_ANNO_MASK;
 787                 switch (*acks++) {
 788                 case RXRPC_ACK_TYPE_ACK:
 789                         summary->nr_acks++;
 790                         if (anno_type == RXRPC_TX_ANNO_ACK)
 791                                 continue;
 792                         summary->nr_new_acks++;
 793                         call->rxtx_annotations[ix] =
 794                                 RXRPC_TX_ANNO_ACK | annotation;
 795                         break;
 796                 case RXRPC_ACK_TYPE_NACK:
 797                         if (!summary->nr_nacks &&
 798                             call->acks_lowest_nak != seq) {
 799                                 call->acks_lowest_nak = seq;
 800                                 summary->new_low_nack = true;
 801                         }
 802                         summary->nr_nacks++;
 803                         if (anno_type == RXRPC_TX_ANNO_NAK)
 804                                 continue;
 805                         summary->nr_new_nacks++;
 806                         if (anno_type == RXRPC_TX_ANNO_RETRANS)
 807                                 continue;
 808                         call->rxtx_annotations[ix] =
 809                                 RXRPC_TX_ANNO_NAK | annotation;
 810                         break;
 811                 default:
 812                         return rxrpc_proto_abort("SFT", call, 0);
 813                 }
 814         }
 815 }
 816
 817 /*
 818  * Return true if the ACK is valid - ie. it doesn't appear to have regressed
 819  * with respect to the ack state conveyed by preceding ACKs.
 820  */
 821 static bool rxrpc_is_ack_valid(struct rxrpc_call *call,
 822                                rxrpc_seq_t first_pkt, rxrpc_seq_t prev_pkt)
 823 {
 824         rxrpc_seq_t base = READ_ONCE(call->acks_first_seq);
 825
 826         if (after(first_pkt, base))
 827                 return true; /* The window advanced */
 828
 829         if (before(first_pkt, base))
 830                 return false; /* firstPacket regressed */
 831
 832         if (after_eq(prev_pkt, call->acks_prev_seq))
 833                 return true; /* previousPacket hasn't regressed. */
 834
 835         /* Some rx implementations put a serial number in previousPacket. */
 836         if (after_eq(prev_pkt, base + call->tx_winsize))
 837                 return false;
 838         return true;
 839 }
 840
 841 /*
 842  * Process an ACK packet.
 843  *
 844  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 845  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 846  *
 847  * A hard-ACK means that a packet has been processed and may be discarded; a
 848  * soft-ACK means that the packet may be discarded and retransmission
 849  * requested.  A phase is complete when all packets are hard-ACK'd.
 850  */
 851 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 852 {
 853         struct rxrpc_ack_summary summary = { 0 };
 854         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 855         union {
 856                 struct rxrpc_ackpacket ack;
 857                 struct rxrpc_ackinfo info;
 858                 u8 acks[RXRPC_MAXACKS];
 859         } buf;
 860         rxrpc_serial_t ack_serial, acked_serial;
 861         rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
 862         int nr_acks, offset, ioffset;
 863
 864         _enter("");
 865
 866         offset = sizeof(struct rxrpc_wire_header);
 867         if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
 868                 _debug("extraction failure");
 869                 return rxrpc_proto_abort("XAK", call, 0);
 870         }
 871         offset += sizeof(buf.ack);
 872
 873         ack_serial = sp->hdr.serial;
 874         acked_serial = ntohl(buf.ack.serial);
 875         first_soft_ack = ntohl(buf.ack.firstPacket);
 876         prev_pkt = ntohl(buf.ack.previousPacket);
 877         hard_ack = first_soft_ack - 1;
 878         nr_acks = buf.ack.nAcks;
 879         summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 880                               buf.ack.reason : RXRPC_ACK__INVALID);
 881
 882         trace_rxrpc_rx_ack(call, ack_serial, acked_serial,
 883                            first_soft_ack, prev_pkt,
 884                            summary.ack_reason, nr_acks);
 885
 886         switch (buf.ack.reason) {
 887         case RXRPC_ACK_PING_RESPONSE:
 888                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 889                                           ack_serial);
 890                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 891                                          rxrpc_rtt_rx_ping_response);
 892                 break;
 893         case RXRPC_ACK_REQUESTED:
 894                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 895                                          rxrpc_rtt_rx_requested_ack);
 896                 break;
 897         default:
 898                 if (acked_serial != 0)
 899                         rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 900                                                  rxrpc_rtt_rx_cancel);
 901                 break;
 902         }
 903
 904         if (buf.ack.reason == RXRPC_ACK_PING) {
 905                 _proto("Rx ACK %%%u PING Request", ack_serial);
 906                 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 907                                   ack_serial, true, true,
 908                                   rxrpc_propose_ack_respond_to_ping);
 909         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 910                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 911                                   ack_serial, true, true,
 912                                   rxrpc_propose_ack_respond_to_ack);
 913         }
 914
 915         /* If we get an EXCEEDS_WINDOW ACK from the server, it probably
 916          * indicates that the client address changed due to NAT.  The server
 917          * lost the call because it switched to a different peer.
 918          */
 919         if (unlikely(buf.ack.reason == RXRPC_ACK_EXCEEDS_WINDOW) &&
 920             first_soft_ack == 1 &&
 921             prev_pkt == 0 &&
 922             rxrpc_is_client_call(call)) {
 923                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 924                                           0, -ENETRESET);
 925                 return;
 926         }
 927
 928         /* If we get an OUT_OF_SEQUENCE ACK from the server, that can also
 929          * indicate a change of address.  However, we can retransmit the call
 930          * if we still have it buffered to the beginning.
 931          */
 932         if (unlikely(buf.ack.reason == RXRPC_ACK_OUT_OF_SEQUENCE) &&
 933             first_soft_ack == 1 &&
 934             prev_pkt == 0 &&
 935             call->tx_hard_ack == 0 &&
 936             rxrpc_is_client_call(call)) {
 937                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 938                                           0, -ENETRESET);
 939                 return;
 940         }
 941
 942         /* Discard any out-of-order or duplicate ACKs (outside lock). */
 943         if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 944                 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 945                                            first_soft_ack, call->acks_first_seq,
 946                                            prev_pkt, call->acks_prev_seq);
 947                 return;
 948         }
 949
 950         buf.info.rxMTU = 0;
 951         ioffset = offset + nr_acks + 3;
 952         if (skb->len >= ioffset + sizeof(buf.info) &&
 953             skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
 954                 return rxrpc_proto_abort("XAI", call, 0);
 955
 956         spin_lock(&call->input_lock);
 957
 958         /* Discard any out-of-order or duplicate ACKs (inside lock). */
 959         if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 960                 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 961                                            first_soft_ack, call->acks_first_seq,
 962                                            prev_pkt, call->acks_prev_seq);
 963                 goto out;
 964         }
 965         call->acks_latest_ts = skb->tstamp;
 966
 967         call->acks_first_seq = first_soft_ack;
 968         call->acks_prev_seq = prev_pkt;
 969
 970         /* Parse rwind and mtu sizes if provided. */
 971         if (buf.info.rxMTU)
 972                 rxrpc_input_ackinfo(call, skb, &buf.info);
 973
 974         if (first_soft_ack == 0) {
 975                 rxrpc_proto_abort("AK0", call, 0);
 976                 goto out;
 977         }
 978
 979         /* Ignore ACKs unless we are or have just been transmitting. */
 980         switch (READ_ONCE(call->state)) {
 981         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 982         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 983         case RXRPC_CALL_SERVER_SEND_REPLY:
 984         case RXRPC_CALL_SERVER_AWAIT_ACK:
 985                 break;
 986         default:
 987                 goto out;
 988         }
 989
 990         if (before(hard_ack, call->tx_hard_ack) ||
 991             after(hard_ack, call->tx_top)) {
 992                 rxrpc_proto_abort("AKW", call, 0);
 993                 goto out;
 994         }
 995         if (nr_acks > call->tx_top - hard_ack) {
 996                 rxrpc_proto_abort("AKN", call, 0);
 997                 goto out;
 998         }
 999
1000         if (after(hard_ack, call->tx_hard_ack)) {
1001                 if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
1002                         rxrpc_end_tx_phase(call, false, "ETA");
1003                         goto out;
1004                 }
1005         }
1006
1007         if (nr_acks > 0) {
1008                 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0) {
1009                         rxrpc_proto_abort("XSA", call, 0);
1010                         goto out;
1011                 }
1012                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
1013                                       &summary);
1014         }
1015
1016         if (call->rxtx_annotations[call->tx_top & RXRPC_RXTX_BUFF_MASK] &
1017             RXRPC_TX_ANNO_LAST &&
1018             summary.nr_acks == call->tx_top - hard_ack &&
1019             rxrpc_is_client_call(call))
1020                 rxrpc_propose_ACK(call, RXRPC_ACK_PING, ack_serial,
1021                                   false, true,
1022                                   rxrpc_propose_ack_ping_for_lost_reply);
1023
1024         rxrpc_congestion_management(call, skb, &summary, acked_serial);
1025 out:
1026         spin_unlock(&call->input_lock);
1027 }
1028
1029 /*
1030  * Process an ACKALL packet.
1031  */
1032 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
1033 {
1034         struct rxrpc_ack_summary summary = { 0 };
1035         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1036
1037         _proto("Rx ACKALL %%%u", sp->hdr.serial);
1038
1039         spin_lock(&call->input_lock);
1040
1041         if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
1042                 rxrpc_end_tx_phase(call, false, "ETL");
1043
1044         spin_unlock(&call->input_lock);
1045 }
1046
1047 /*
1048  * Process an ABORT packet directed at a call.
1049  */
1050 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
1051 {
1052         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1053         __be32 wtmp;
1054         u32 abort_code = RX_CALL_DEAD;
1055
1056         _enter("");
1057
1058         if (skb->len >= 4 &&
1059             skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1060                           &wtmp, sizeof(wtmp)) >= 0)
1061                 abort_code = ntohl(wtmp);
1062
1063         trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
1064
1065         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
1066
1067         rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
1068                                   abort_code, -ECONNABORTED);
1069 }
1070
1071 /*
1072  * Process an incoming call packet.
1073  */
1074 static void rxrpc_input_call_packet(struct rxrpc_call *call,
1075                                     struct sk_buff *skb)
1076 {
1077         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1078         unsigned long timo;
1079
1080         _enter("%p,%p", call, skb);
1081
1082         timo = READ_ONCE(call->next_rx_timo);
1083         if (timo) {
1084                 unsigned long now = jiffies, expect_rx_by;
1085
1086                 expect_rx_by = now + timo;
1087                 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
1088                 rxrpc_reduce_call_timer(call, expect_rx_by, now,
1089                                         rxrpc_timer_set_for_normal);
1090         }
1091
1092         switch (sp->hdr.type) {
1093         case RXRPC_PACKET_TYPE_DATA:
1094                 rxrpc_input_data(call, skb);
1095                 goto no_free;
1096
1097         case RXRPC_PACKET_TYPE_ACK:
1098                 rxrpc_input_ack(call, skb);
1099                 break;
1100
1101         case RXRPC_PACKET_TYPE_BUSY:
1102                 _proto("Rx BUSY %%%u", sp->hdr.serial);
1103
1104                 /* Just ignore BUSY packets from the server; the retry and
1105                  * lifespan timers will take care of business.  BUSY packets
1106                  * from the client don't make sense.
1107                  */
1108                 break;
1109
1110         case RXRPC_PACKET_TYPE_ABORT:
1111                 rxrpc_input_abort(call, skb);
1112                 break;
1113
1114         case RXRPC_PACKET_TYPE_ACKALL:
1115                 rxrpc_input_ackall(call, skb);
1116                 break;
1117
1118         default:
1119                 break;
1120         }
1121
1122         rxrpc_free_skb(skb, rxrpc_skb_freed);
1123 no_free:
1124         _leave("");
1125 }
1126
1127 /*
1128  * Handle a new service call on a channel implicitly completing the preceding
1129  * call on that channel.  This does not apply to client conns.
1130  *
1131  * TODO: If callNumber > call_id + 1, renegotiate security.
1132  */
1133 static void rxrpc_input_implicit_end_call(struct rxrpc_sock *rx,
1134                                           struct rxrpc_connection *conn,
1135                                           struct rxrpc_call *call)
1136 {
1137         switch (READ_ONCE(call->state)) {
1138         case RXRPC_CALL_SERVER_AWAIT_ACK:
1139                 rxrpc_call_completed(call);
1140                 fallthrough;
1141         case RXRPC_CALL_COMPLETE:
1142                 break;
1143         default:
1144                 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
1145                         set_bit(RXRPC_CALL_EV_ABORT, &call->events);
1146                         rxrpc_queue_call(call);
1147                 }
1148                 trace_rxrpc_improper_term(call);
1149                 break;
1150         }
1151
1152         spin_lock(&rx->incoming_lock);
1153         __rxrpc_disconnect_call(conn, call);
1154         spin_unlock(&rx->incoming_lock);
1155 }
1156
1157 /*
1158  * post connection-level events to the connection
1159  * - this includes challenges, responses, some aborts and call terminal packet
1160  *   retransmission.
1161  */
1162 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
1163                                       struct sk_buff *skb)
1164 {
1165         _enter("%p,%p", conn, skb);
1166
1167         skb_queue_tail(&conn->rx_queue, skb);
1168         rxrpc_queue_conn(conn);
1169 }
1170
1171 /*
1172  * post endpoint-level events to the local endpoint
1173  * - this includes debug and version messages
1174  */
1175 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
1176                                        struct sk_buff *skb)
1177 {
1178         _enter("%p,%p", local, skb);
1179
1180         if (rxrpc_get_local_maybe(local)) {
1181                 skb_queue_tail(&local->event_queue, skb);
1182                 rxrpc_queue_local(local);
1183         } else {
1184                 rxrpc_free_skb(skb, rxrpc_skb_freed);
1185         }
1186 }
1187
1188 /*
1189  * put a packet up for transport-level abort
1190  */
1191 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1192 {
1193         if (rxrpc_get_local_maybe(local)) {
1194                 skb_queue_tail(&local->reject_queue, skb);
1195                 rxrpc_queue_local(local);
1196         } else {
1197                 rxrpc_free_skb(skb, rxrpc_skb_freed);
1198         }
1199 }
1200
1201 /*
1202  * Extract the wire header from a packet and translate the byte order.
1203  */
1204 static noinline
1205 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1206 {
1207         struct rxrpc_wire_header whdr;
1208
1209         /* dig out the RxRPC connection details */
1210         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1211                 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1212                                       tracepoint_string("bad_hdr"));
1213                 return -EBADMSG;
1214         }
1215
1216         memset(sp, 0, sizeof(*sp));
1217         sp->hdr.epoch           = ntohl(whdr.epoch);
1218         sp->hdr.cid             = ntohl(whdr.cid);
1219         sp->hdr.callNumber      = ntohl(whdr.callNumber);
1220         sp->hdr.seq             = ntohl(whdr.seq);
1221         sp->hdr.serial          = ntohl(whdr.serial);
1222         sp->hdr.flags           = whdr.flags;
1223         sp->hdr.type            = whdr.type;
1224         sp->hdr.userStatus      = whdr.userStatus;
1225         sp->hdr.securityIndex   = whdr.securityIndex;
1226         sp->hdr._rsvd           = ntohs(whdr._rsvd);
1227         sp->hdr.serviceId       = ntohs(whdr.serviceId);
1228         return 0;
1229 }
1230
1231 /*
1232  * handle data received on the local endpoint
1233  * - may be called in interrupt context
1234  *
1235  * [!] Note that as this is called from the encap_rcv hook, the socket is not
1236  * held locked by the caller and nothing prevents sk_user_data on the UDP from
1237  * being cleared in the middle of processing this function.
1238  *
1239  * Called with the RCU read lock held from the IP layer via UDP.
1240  */
1241 int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
1242 {
1243         struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
1244         struct rxrpc_connection *conn;
1245         struct rxrpc_channel *chan;
1246         struct rxrpc_call *call = NULL;
1247         struct rxrpc_skb_priv *sp;
1248         struct rxrpc_peer *peer = NULL;
1249         struct rxrpc_sock *rx = NULL;
1250         unsigned int channel;
1251
1252         _enter("%p", udp_sk);
1253
1254         if (unlikely(!local)) {
1255                 kfree_skb(skb);
1256                 return 0;
1257         }
1258         if (skb->tstamp == 0)
1259                 skb->tstamp = ktime_get_real();
1260
1261         rxrpc_new_skb(skb, rxrpc_skb_received);
1262
1263         skb_pull(skb, sizeof(struct udphdr));
1264
1265         /* The UDP protocol already released all skb resources;
1266          * we are free to add our own data there.
1267          */
1268         sp = rxrpc_skb(skb);
1269
1270         /* dig out the RxRPC connection details */
1271         if (rxrpc_extract_header(sp, skb) < 0)
1272                 goto bad_message;
1273
1274         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1275                 static int lose;
1276                 if ((lose++ & 7) == 7) {
1277                         trace_rxrpc_rx_lose(sp);
1278                         rxrpc_free_skb(skb, rxrpc_skb_lost);
1279                         return 0;
1280                 }
1281         }
1282
1283         if (skb->tstamp == 0)
1284                 skb->tstamp = ktime_get_real();
1285         trace_rxrpc_rx_packet(sp);
1286
1287         switch (sp->hdr.type) {
1288         case RXRPC_PACKET_TYPE_VERSION:
1289                 if (rxrpc_to_client(sp))
1290                         goto discard;
1291                 rxrpc_post_packet_to_local(local, skb);
1292                 goto out;
1293
1294         case RXRPC_PACKET_TYPE_BUSY:
1295                 if (rxrpc_to_server(sp))
1296                         goto discard;
1297                 fallthrough;
1298         case RXRPC_PACKET_TYPE_ACK:
1299         case RXRPC_PACKET_TYPE_ACKALL:
1300                 if (sp->hdr.callNumber == 0)
1301                         goto bad_message;
1302                 fallthrough;
1303         case RXRPC_PACKET_TYPE_ABORT:
1304                 break;
1305
1306         case RXRPC_PACKET_TYPE_DATA:
1307                 if (sp->hdr.callNumber == 0 ||
1308                     sp->hdr.seq == 0)
1309                         goto bad_message;
1310                 if (!rxrpc_validate_data(skb))
1311                         goto bad_message;
1312
1313                 /* Unshare the packet so that it can be modified for in-place
1314                  * decryption.
1315                  */
1316                 if (sp->hdr.securityIndex != 0) {
1317                         struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC);
1318                         if (!nskb) {
1319                                 rxrpc_eaten_skb(skb, rxrpc_skb_unshared_nomem);
1320                                 goto out;
1321                         }
1322
1323                         if (nskb != skb) {
1324                                 rxrpc_eaten_skb(skb, rxrpc_skb_received);
1325                                 skb = nskb;
1326                                 rxrpc_new_skb(skb, rxrpc_skb_unshared);
1327                                 sp = rxrpc_skb(skb);
1328                         }
1329                 }
1330                 break;
1331
1332         case RXRPC_PACKET_TYPE_CHALLENGE:
1333                 if (rxrpc_to_server(sp))
1334                         goto discard;
1335                 break;
1336         case RXRPC_PACKET_TYPE_RESPONSE:
1337                 if (rxrpc_to_client(sp))
1338                         goto discard;
1339                 break;
1340
1341                 /* Packet types 9-11 should just be ignored. */
1342         case RXRPC_PACKET_TYPE_PARAMS:
1343         case RXRPC_PACKET_TYPE_10:
1344         case RXRPC_PACKET_TYPE_11:
1345                 goto discard;
1346
1347         default:
1348                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
1349                 goto bad_message;
1350         }
1351
1352         if (sp->hdr.serviceId == 0)
1353                 goto bad_message;
1354
1355         if (rxrpc_to_server(sp)) {
1356                 /* Weed out packets to services we're not offering.  Packets
1357                  * that would begin a call are explicitly rejected and the rest
1358                  * are just discarded.
1359                  */
1360                 rx = rcu_dereference(local->service);
1361                 if (!rx || (sp->hdr.serviceId != rx->srx.srx_service &&
1362                             sp->hdr.serviceId != rx->second_service)) {
1363                         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
1364                             sp->hdr.seq == 1)
1365                                 goto unsupported_service;
1366                         goto discard;
1367                 }
1368         }
1369
1370         conn = rxrpc_find_connection_rcu(local, skb, &peer);
1371         if (conn) {
1372                 if (sp->hdr.securityIndex != conn->security_ix)
1373                         goto wrong_security;
1374
1375                 if (sp->hdr.serviceId != conn->service_id) {
1376                         int old_id;
1377
1378                         if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags))
1379                                 goto reupgrade;
1380                         old_id = cmpxchg(&conn->service_id, conn->params.service_id,
1381                                          sp->hdr.serviceId);
1382
1383                         if (old_id != conn->params.service_id &&
1384                             old_id != sp->hdr.serviceId)
1385                                 goto reupgrade;
1386                 }
1387
1388                 if (sp->hdr.callNumber == 0) {
1389                         /* Connection-level packet */
1390                         _debug("CONN %p {%d}", conn, conn->debug_id);
1391                         rxrpc_post_packet_to_conn(conn, skb);
1392                         goto out;
1393                 }
1394
1395                 if ((int)sp->hdr.serial - (int)conn->hi_serial > 0)
1396                         conn->hi_serial = sp->hdr.serial;
1397
1398                 /* Call-bound packets are routed by connection channel. */
1399                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1400                 chan = &conn->channels[channel];
1401
1402                 /* Ignore really old calls */
1403                 if (sp->hdr.callNumber < chan->last_call)
1404                         goto discard;
1405
1406                 if (sp->hdr.callNumber == chan->last_call) {
1407                         if (chan->call ||
1408                             sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
1409                                 goto discard;
1410
1411                         /* For the previous service call, if completed
1412                          * successfully, we discard all further packets.
1413                          */
1414                         if (rxrpc_conn_is_service(conn) &&
1415                             chan->last_type == RXRPC_PACKET_TYPE_ACK)
1416                                 goto discard;
1417
1418                         /* But otherwise we need to retransmit the final packet
1419                          * from data cached in the connection record.
1420                          */
1421                         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
1422                                 trace_rxrpc_rx_data(chan->call_debug_id,
1423                                                     sp->hdr.seq,
1424                                                     sp->hdr.serial,
1425                                                     sp->hdr.flags, 0);
1426                         rxrpc_post_packet_to_conn(conn, skb);
1427                         goto out;
1428                 }
1429
1430                 call = rcu_dereference(chan->call);
1431
1432                 if (sp->hdr.callNumber > chan->call_id) {
1433                         if (rxrpc_to_client(sp))
1434                                 goto reject_packet;
1435                         if (call)
1436                                 rxrpc_input_implicit_end_call(rx, conn, call);
1437                         call = NULL;
1438                 }
1439
1440                 if (call) {
1441                         if (sp->hdr.serviceId != call->service_id)
1442                                 call->service_id = sp->hdr.serviceId;
1443                         if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
1444                                 call->rx_serial = sp->hdr.serial;
1445                         if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
1446                                 set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
1447                 }
1448         }
1449
1450         if (!call || refcount_read(&call->ref) == 0) {
1451                 if (rxrpc_to_client(sp) ||
1452                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1453                         goto bad_message;
1454                 if (sp->hdr.seq != 1)
1455                         goto discard;
1456                 call = rxrpc_new_incoming_call(local, rx, skb);
1457                 if (!call)
1458                         goto reject_packet;
1459         }
1460
1461         /* Process a call packet; this either discards or passes on the ref
1462          * elsewhere.
1463          */
1464         rxrpc_input_call_packet(call, skb);
1465         goto out;
1466
1467 discard:
1468         rxrpc_free_skb(skb, rxrpc_skb_freed);
1469 out:
1470         trace_rxrpc_rx_done(0, 0);
1471         return 0;
1472
1473 wrong_security:
1474         trace_rxrpc_abort(0, "SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1475                           RXKADINCONSISTENCY, EBADMSG);
1476         skb->priority = RXKADINCONSISTENCY;
1477         goto post_abort;
1478
1479 unsupported_service:
1480         trace_rxrpc_abort(0, "INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1481                           RX_INVALID_OPERATION, EOPNOTSUPP);
1482         skb->priority = RX_INVALID_OPERATION;
1483         goto post_abort;
1484
1485 reupgrade:
1486         trace_rxrpc_abort(0, "UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1487                           RX_PROTOCOL_ERROR, EBADMSG);
1488         goto protocol_error;
1489
1490 bad_message:
1491         trace_rxrpc_abort(0, "BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1492                           RX_PROTOCOL_ERROR, EBADMSG);
1493 protocol_error:
1494         skb->priority = RX_PROTOCOL_ERROR;
1495 post_abort:
1496         skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
1497 reject_packet:
1498         trace_rxrpc_rx_done(skb->mark, skb->priority);
1499         rxrpc_reject_packet(local, skb);
1500         _leave(" [badmsg]");
1501         return 0;
1502 }