net/rxrpc/input.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* RxRPC packet reception
   3  *
   4  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include "ar-internal.h"
  11
  12 static void rxrpc_proto_abort(const char *why,
  13                               struct rxrpc_call *call, rxrpc_seq_t seq)
  14 {
  15         if (rxrpc_abort_call(why, call, seq, RX_PROTOCOL_ERROR, -EBADMSG)) {
  16                 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
  17                 rxrpc_queue_call(call);
  18         }
  19 }
  20
  21 /*
  22  * Do TCP-style congestion management [RFC 5681].
  23  */
  24 static void rxrpc_congestion_management(struct rxrpc_call *call,
  25                                         struct sk_buff *skb,
  26                                         struct rxrpc_ack_summary *summary,
  27                                         rxrpc_serial_t acked_serial)
  28 {
  29         enum rxrpc_congest_change change = rxrpc_cong_no_change;
  30         unsigned int cumulative_acks = call->cong_cumul_acks;
  31         unsigned int cwnd = call->cong_cwnd;
  32         bool resend = false;
  33
  34         summary->flight_size =
  35                 (call->tx_top - call->acks_hard_ack) - summary->nr_acks;
  36
  37         if (test_and_clear_bit(RXRPC_CALL_RETRANS_TIMEOUT, &call->flags)) {
  38                 summary->retrans_timeo = true;
  39                 call->cong_ssthresh = max_t(unsigned int,
  40                                             summary->flight_size / 2, 2);
  41                 cwnd = 1;
  42                 if (cwnd >= call->cong_ssthresh &&
  43                     call->cong_mode == RXRPC_CALL_SLOW_START) {
  44                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  45                         call->cong_tstamp = skb->tstamp;
  46                         cumulative_acks = 0;
  47                 }
  48         }
  49
  50         cumulative_acks += summary->nr_new_acks;
  51         cumulative_acks += summary->nr_rot_new_acks;
  52         if (cumulative_acks > 255)
  53                 cumulative_acks = 255;
  54
  55         summary->mode = call->cong_mode;
  56         summary->cwnd = call->cong_cwnd;
  57         summary->ssthresh = call->cong_ssthresh;
  58         summary->cumulative_acks = cumulative_acks;
  59         summary->dup_acks = call->cong_dup_acks;
  60
  61         switch (call->cong_mode) {
  62         case RXRPC_CALL_SLOW_START:
  63                 if (summary->nr_nacks > 0)
  64                         goto packet_loss_detected;
  65                 if (summary->cumulative_acks > 0)
  66                         cwnd += 1;
  67                 if (cwnd >= call->cong_ssthresh) {
  68                         call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
  69                         call->cong_tstamp = skb->tstamp;
  70                 }
  71                 goto out;
  72
  73         case RXRPC_CALL_CONGEST_AVOIDANCE:
  74                 if (summary->nr_nacks > 0)
  75                         goto packet_loss_detected;
  76
  77                 /* We analyse the number of packets that get ACK'd per RTT
  78                  * period and increase the window if we managed to fill it.
  79                  */
  80                 if (call->peer->rtt_count == 0)
  81                         goto out;
  82                 if (ktime_before(skb->tstamp,
  83                                  ktime_add_us(call->cong_tstamp,
  84                                               call->peer->srtt_us >> 3)))
  85                         goto out_no_clear_ca;
  86                 change = rxrpc_cong_rtt_window_end;
  87                 call->cong_tstamp = skb->tstamp;
  88                 if (cumulative_acks >= cwnd)
  89                         cwnd++;
  90                 goto out;
  91
  92         case RXRPC_CALL_PACKET_LOSS:
  93                 if (summary->nr_nacks == 0)
  94                         goto resume_normality;
  95
  96                 if (summary->new_low_nack) {
  97                         change = rxrpc_cong_new_low_nack;
  98                         call->cong_dup_acks = 1;
  99                         if (call->cong_extra > 1)
 100                                 call->cong_extra = 1;
 101                         goto send_extra_data;
 102                 }
 103
 104                 call->cong_dup_acks++;
 105                 if (call->cong_dup_acks < 3)
 106                         goto send_extra_data;
 107
 108                 change = rxrpc_cong_begin_retransmission;
 109                 call->cong_mode = RXRPC_CALL_FAST_RETRANSMIT;
 110                 call->cong_ssthresh = max_t(unsigned int,
 111                                             summary->flight_size / 2, 2);
 112                 cwnd = call->cong_ssthresh + 3;
 113                 call->cong_extra = 0;
 114                 call->cong_dup_acks = 0;
 115                 resend = true;
 116                 goto out;
 117
 118         case RXRPC_CALL_FAST_RETRANSMIT:
 119                 if (!summary->new_low_nack) {
 120                         if (summary->nr_new_acks == 0)
 121                                 cwnd += 1;
 122                         call->cong_dup_acks++;
 123                         if (call->cong_dup_acks == 2) {
 124                                 change = rxrpc_cong_retransmit_again;
 125                                 call->cong_dup_acks = 0;
 126                                 resend = true;
 127                         }
 128                 } else {
 129                         change = rxrpc_cong_progress;
 130                         cwnd = call->cong_ssthresh;
 131                         if (summary->nr_nacks == 0)
 132                                 goto resume_normality;
 133                 }
 134                 goto out;
 135
 136         default:
 137                 BUG();
 138                 goto out;
 139         }
 140
 141 resume_normality:
 142         change = rxrpc_cong_cleared_nacks;
 143         call->cong_dup_acks = 0;
 144         call->cong_extra = 0;
 145         call->cong_tstamp = skb->tstamp;
 146         if (cwnd < call->cong_ssthresh)
 147                 call->cong_mode = RXRPC_CALL_SLOW_START;
 148         else
 149                 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
 150 out:
 151         cumulative_acks = 0;
 152 out_no_clear_ca:
 153         if (cwnd >= RXRPC_TX_MAX_WINDOW)
 154                 cwnd = RXRPC_TX_MAX_WINDOW;
 155         call->cong_cwnd = cwnd;
 156         call->cong_cumul_acks = cumulative_acks;
 157         trace_rxrpc_congest(call, summary, acked_serial, change);
 158         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 159                 rxrpc_queue_call(call);
 160         return;
 161
 162 packet_loss_detected:
 163         change = rxrpc_cong_saw_nack;
 164         call->cong_mode = RXRPC_CALL_PACKET_LOSS;
 165         call->cong_dup_acks = 0;
 166         goto send_extra_data;
 167
 168 send_extra_data:
 169         /* Send some previously unsent DATA if we have some to advance the ACK
 170          * state.
 171          */
 172         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) ||
 173             summary->nr_acks != call->tx_top - call->acks_hard_ack) {
 174                 call->cong_extra++;
 175                 wake_up(&call->waitq);
 176         }
 177         goto out_no_clear_ca;
 178 }
 179
 180 /*
 181  * Apply a hard ACK by advancing the Tx window.
 182  */
 183 static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,
 184                                    struct rxrpc_ack_summary *summary)
 185 {
 186         struct rxrpc_txbuf *txb;
 187         bool rot_last = false;
 188
 189         list_for_each_entry_rcu(txb, &call->tx_buffer, call_link, false) {
 190                 if (before_eq(txb->seq, call->acks_hard_ack))
 191                         continue;
 192                 if (!test_bit(RXRPC_TXBUF_ACKED, &txb->flags))
 193                         summary->nr_rot_new_acks++;
 194                 if (test_bit(RXRPC_TXBUF_LAST, &txb->flags)) {
 195                         set_bit(RXRPC_CALL_TX_LAST, &call->flags);
 196                         rot_last = true;
 197                 }
 198                 if (txb->seq == to)
 199                         break;
 200         }
 201
 202         if (rot_last)
 203                 set_bit(RXRPC_CALL_TX_ALL_ACKED, &call->flags);
 204
 205         _enter("%x,%x,%x,%d", to, call->acks_hard_ack, call->tx_top, rot_last);
 206
 207         if (call->acks_lowest_nak == call->acks_hard_ack) {
 208                 call->acks_lowest_nak = to;
 209         } else if (before_eq(call->acks_lowest_nak, to)) {
 210                 summary->new_low_nack = true;
 211                 call->acks_lowest_nak = to;
 212         }
 213
 214         smp_store_release(&call->acks_hard_ack, to);
 215
 216         trace_rxrpc_txqueue(call, (rot_last ?
 217                                    rxrpc_txqueue_rotate_last :
 218                                    rxrpc_txqueue_rotate));
 219         wake_up(&call->waitq);
 220         return rot_last;
 221 }
 222
 223 /*
 224  * End the transmission phase of a call.
 225  *
 226  * This occurs when we get an ACKALL packet, the first DATA packet of a reply,
 227  * or a final ACK packet.
 228  */
 229 static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun,
 230                                const char *abort_why)
 231 {
 232         unsigned int state;
 233
 234         ASSERT(test_bit(RXRPC_CALL_TX_LAST, &call->flags));
 235
 236         write_lock(&call->state_lock);
 237
 238         state = call->state;
 239         switch (state) {
 240         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 241         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 242                 if (reply_begun)
 243                         call->state = state = RXRPC_CALL_CLIENT_RECV_REPLY;
 244                 else
 245                         call->state = state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 246                 break;
 247
 248         case RXRPC_CALL_SERVER_AWAIT_ACK:
 249                 __rxrpc_call_completed(call);
 250                 state = call->state;
 251                 break;
 252
 253         default:
 254                 goto bad_state;
 255         }
 256
 257         write_unlock(&call->state_lock);
 258         if (state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 259                 trace_rxrpc_txqueue(call, rxrpc_txqueue_await_reply);
 260         else
 261                 trace_rxrpc_txqueue(call, rxrpc_txqueue_end);
 262         _leave(" = ok");
 263         return true;
 264
 265 bad_state:
 266         write_unlock(&call->state_lock);
 267         kdebug("end_tx %s", rxrpc_call_states[call->state]);
 268         rxrpc_proto_abort(abort_why, call, call->tx_top);
 269         return false;
 270 }
 271
 272 /*
 273  * Begin the reply reception phase of a call.
 274  */
 275 static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 276 {
 277         struct rxrpc_ack_summary summary = { 0 };
 278         unsigned long now, timo;
 279         rxrpc_seq_t top = READ_ONCE(call->tx_top);
 280
 281         if (call->ackr_reason) {
 282                 now = jiffies;
 283                 timo = now + MAX_JIFFY_OFFSET;
 284                 WRITE_ONCE(call->resend_at, timo);
 285                 WRITE_ONCE(call->delay_ack_at, timo);
 286                 trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);
 287         }
 288
 289         if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {
 290                 if (!rxrpc_rotate_tx_window(call, top, &summary)) {
 291                         rxrpc_proto_abort("TXL", call, top);
 292                         return false;
 293                 }
 294         }
 295         return rxrpc_end_tx_phase(call, true, "ETD");
 296 }
 297
 298 static void rxrpc_input_update_ack_window(struct rxrpc_call *call,
 299                                           rxrpc_seq_t window, rxrpc_seq_t wtop)
 300 {
 301         atomic64_set_release(&call->ackr_window, ((u64)wtop) << 32 | window);
 302 }
 303
 304 /*
 305  * Push a DATA packet onto the Rx queue.
 306  */
 307 static void rxrpc_input_queue_data(struct rxrpc_call *call, struct sk_buff *skb,
 308                                    rxrpc_seq_t window, rxrpc_seq_t wtop,
 309                                    enum rxrpc_receive_trace why)
 310 {
 311         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 312         bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
 313
 314         __skb_queue_tail(&call->recvmsg_queue, skb);
 315         rxrpc_input_update_ack_window(call, window, wtop);
 316
 317         trace_rxrpc_receive(call, last ? why + 1 : why, sp->hdr.serial, sp->hdr.seq);
 318 }
 319
 320 /*
 321  * Process a DATA packet.
 322  */
 323 static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb)
 324 {
 325         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 326         struct sk_buff *oos;
 327         rxrpc_serial_t serial = sp->hdr.serial;
 328         u64 win = atomic64_read(&call->ackr_window);
 329         rxrpc_seq_t window = lower_32_bits(win);
 330         rxrpc_seq_t wtop = upper_32_bits(win);
 331         rxrpc_seq_t wlimit = window + call->rx_winsize - 1;
 332         rxrpc_seq_t seq = sp->hdr.seq;
 333         bool last = sp->hdr.flags & RXRPC_LAST_PACKET;
 334         int ack_reason = -1;
 335
 336         rxrpc_inc_stat(call->rxnet, stat_rx_data);
 337         if (sp->hdr.flags & RXRPC_REQUEST_ACK)
 338                 rxrpc_inc_stat(call->rxnet, stat_rx_data_reqack);
 339         if (sp->hdr.flags & RXRPC_JUMBO_PACKET)
 340                 rxrpc_inc_stat(call->rxnet, stat_rx_data_jumbo);
 341
 342         if (last) {
 343                 if (test_and_set_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 344                     seq + 1 != wtop) {
 345                         rxrpc_proto_abort("LSN", call, seq);
 346                         goto err_free;
 347                 }
 348         } else {
 349                 if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
 350                     after_eq(seq, wtop)) {
 351                         pr_warn("Packet beyond last: c=%x q=%x window=%x-%x wlimit=%x\n",
 352                                 call->debug_id, seq, window, wtop, wlimit);
 353                         rxrpc_proto_abort("LSA", call, seq);
 354                         goto err_free;
 355                 }
 356         }
 357
 358         if (after(seq, call->rx_highest_seq))
 359                 call->rx_highest_seq = seq;
 360
 361         trace_rxrpc_rx_data(call->debug_id, seq, serial, sp->hdr.flags);
 362
 363         if (before(seq, window)) {
 364                 ack_reason = RXRPC_ACK_DUPLICATE;
 365                 goto send_ack;
 366         }
 367         if (after(seq, wlimit)) {
 368                 ack_reason = RXRPC_ACK_EXCEEDS_WINDOW;
 369                 goto send_ack;
 370         }
 371
 372         /* Queue the packet. */
 373         if (seq == window) {
 374                 rxrpc_seq_t reset_from;
 375                 bool reset_sack = false;
 376
 377                 if (sp->hdr.flags & RXRPC_REQUEST_ACK)
 378                         ack_reason = RXRPC_ACK_REQUESTED;
 379                 /* Send an immediate ACK if we fill in a hole */
 380                 else if (!skb_queue_empty(&call->rx_oos_queue))
 381                         ack_reason = RXRPC_ACK_DELAY;
 382
 383                 window++;
 384                 if (after(window, wtop))
 385                         wtop = window;
 386
 387                 spin_lock(&call->recvmsg_queue.lock);
 388                 rxrpc_input_queue_data(call, skb, window, wtop, rxrpc_receive_queue);
 389                 skb = NULL;
 390
 391                 while ((oos = skb_peek(&call->rx_oos_queue))) {
 392                         struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
 393
 394                         if (after(osp->hdr.seq, window))
 395                                 break;
 396
 397                         __skb_unlink(oos, &call->rx_oos_queue);
 398                         last = osp->hdr.flags & RXRPC_LAST_PACKET;
 399                         seq = osp->hdr.seq;
 400                         if (!reset_sack) {
 401                                 reset_from = seq;
 402                                 reset_sack = true;
 403                         }
 404
 405                         window++;
 406                         rxrpc_input_queue_data(call, oos, window, wtop,
 407                                                  rxrpc_receive_queue_oos);
 408                 }
 409
 410                 spin_unlock(&call->recvmsg_queue.lock);
 411
 412                 if (reset_sack) {
 413                         do {
 414                                 call->ackr_sack_table[reset_from % RXRPC_SACK_SIZE] = 0;
 415                         } while (reset_from++, before(reset_from, window));
 416                 }
 417         } else {
 418                 bool keep = false;
 419
 420                 ack_reason = RXRPC_ACK_OUT_OF_SEQUENCE;
 421
 422                 if (!call->ackr_sack_table[seq % RXRPC_SACK_SIZE]) {
 423                         call->ackr_sack_table[seq % RXRPC_SACK_SIZE] = 1;
 424                         keep = 1;
 425                 }
 426
 427                 if (after(seq + 1, wtop)) {
 428                         wtop = seq + 1;
 429                         rxrpc_input_update_ack_window(call, window, wtop);
 430                 }
 431
 432                 if (!keep) {
 433                         ack_reason = RXRPC_ACK_DUPLICATE;
 434                         goto send_ack;
 435                 }
 436
 437                 skb_queue_walk(&call->rx_oos_queue, oos) {
 438                         struct rxrpc_skb_priv *osp = rxrpc_skb(oos);
 439
 440                         if (after(osp->hdr.seq, seq)) {
 441                                 __skb_queue_before(&call->rx_oos_queue, oos, skb);
 442                                 goto oos_queued;
 443                         }
 444                 }
 445
 446                 __skb_queue_tail(&call->rx_oos_queue, skb);
 447         oos_queued:
 448                 trace_rxrpc_receive(call, last ? rxrpc_receive_oos_last : rxrpc_receive_oos,
 449                                     sp->hdr.serial, sp->hdr.seq);
 450                 skb = NULL;
 451         }
 452
 453 send_ack:
 454         if (ack_reason < 0 &&
 455             atomic_inc_return(&call->ackr_nr_unacked) > 2 &&
 456             test_and_set_bit(RXRPC_CALL_IDLE_ACK_PENDING, &call->flags)) {
 457                 ack_reason = RXRPC_ACK_IDLE;
 458         } else if (ack_reason >= 0) {
 459                 set_bit(RXRPC_CALL_IDLE_ACK_PENDING, &call->flags);
 460         }
 461
 462         if (ack_reason >= 0)
 463                 rxrpc_send_ACK(call, ack_reason, serial,
 464                                rxrpc_propose_ack_input_data);
 465         else
 466                 rxrpc_propose_delay_ACK(call, serial,
 467                                         rxrpc_propose_ack_input_data);
 468
 469 err_free:
 470         rxrpc_free_skb(skb, rxrpc_skb_freed);
 471 }
 472
 473 /*
 474  * Split a jumbo packet and file the bits separately.
 475  */
 476 static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb)
 477 {
 478         struct rxrpc_jumbo_header jhdr;
 479         struct rxrpc_skb_priv *sp = rxrpc_skb(skb), *jsp;
 480         struct sk_buff *jskb;
 481         unsigned int offset = sizeof(struct rxrpc_wire_header);
 482         unsigned int len = skb->len - offset;
 483
 484         while (sp->hdr.flags & RXRPC_JUMBO_PACKET) {
 485                 if (len < RXRPC_JUMBO_SUBPKTLEN)
 486                         goto protocol_error;
 487                 if (sp->hdr.flags & RXRPC_LAST_PACKET)
 488                         goto protocol_error;
 489                 if (skb_copy_bits(skb, offset + RXRPC_JUMBO_DATALEN,
 490                                   &jhdr, sizeof(jhdr)) < 0)
 491                         goto protocol_error;
 492
 493                 jskb = skb_clone(skb, GFP_ATOMIC);
 494                 if (!jskb) {
 495                         kdebug("couldn't clone");
 496                         return false;
 497                 }
 498                 rxrpc_new_skb(jskb, rxrpc_skb_cloned_jumbo);
 499                 jsp = rxrpc_skb(jskb);
 500                 jsp->offset = offset;
 501                 jsp->len = RXRPC_JUMBO_DATALEN;
 502                 rxrpc_input_data_one(call, jskb);
 503
 504                 sp->hdr.flags = jhdr.flags;
 505                 sp->hdr._rsvd = ntohs(jhdr._rsvd);
 506                 sp->hdr.seq++;
 507                 sp->hdr.serial++;
 508                 offset += RXRPC_JUMBO_SUBPKTLEN;
 509                 len -= RXRPC_JUMBO_SUBPKTLEN;
 510         }
 511
 512         sp->offset = offset;
 513         sp->len    = len;
 514         rxrpc_input_data_one(call, skb);
 515         return true;
 516
 517 protocol_error:
 518         return false;
 519 }
 520
 521 /*
 522  * Process a DATA packet, adding the packet to the Rx ring.  The caller's
 523  * packet ref must be passed on or discarded.
 524  */
 525 static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
 526 {
 527         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 528         enum rxrpc_call_state state;
 529         rxrpc_serial_t serial = sp->hdr.serial;
 530         rxrpc_seq_t seq0 = sp->hdr.seq;
 531
 532         _enter("{%llx,%x},{%u,%x}",
 533                atomic64_read(&call->ackr_window), call->rx_highest_seq,
 534                skb->len, seq0);
 535
 536         _proto("Rx DATA %%%u { #%u f=%02x }",
 537                sp->hdr.serial, seq0, sp->hdr.flags);
 538
 539         state = READ_ONCE(call->state);
 540         if (state >= RXRPC_CALL_COMPLETE) {
 541                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 542                 return;
 543         }
 544
 545         /* Unshare the packet so that it can be modified for in-place
 546          * decryption.
 547          */
 548         if (sp->hdr.securityIndex != 0) {
 549                 struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC);
 550                 if (!nskb) {
 551                         rxrpc_eaten_skb(skb, rxrpc_skb_unshared_nomem);
 552                         return;
 553                 }
 554
 555                 if (nskb != skb) {
 556                         rxrpc_eaten_skb(skb, rxrpc_skb_received);
 557                         skb = nskb;
 558                         rxrpc_new_skb(skb, rxrpc_skb_unshared);
 559                         sp = rxrpc_skb(skb);
 560                 }
 561         }
 562
 563         if (state == RXRPC_CALL_SERVER_RECV_REQUEST) {
 564                 unsigned long timo = READ_ONCE(call->next_req_timo);
 565                 unsigned long now, expect_req_by;
 566
 567                 if (timo) {
 568                         now = jiffies;
 569                         expect_req_by = now + timo;
 570                         WRITE_ONCE(call->expect_req_by, expect_req_by);
 571                         rxrpc_reduce_call_timer(call, expect_req_by, now,
 572                                                 rxrpc_timer_set_for_idle);
 573                 }
 574         }
 575
 576         spin_lock(&call->input_lock);
 577
 578         /* Received data implicitly ACKs all of the request packets we sent
 579          * when we're acting as a client.
 580          */
 581         if ((state == RXRPC_CALL_CLIENT_SEND_REQUEST ||
 582              state == RXRPC_CALL_CLIENT_AWAIT_REPLY) &&
 583             !rxrpc_receiving_reply(call))
 584                 goto out;
 585
 586         if (!rxrpc_input_split_jumbo(call, skb)) {
 587                 rxrpc_proto_abort("VLD", call, sp->hdr.seq);
 588                 goto out;
 589         }
 590         skb = NULL;
 591
 592 out:
 593         trace_rxrpc_notify_socket(call->debug_id, serial);
 594         rxrpc_notify_socket(call);
 595
 596         spin_unlock(&call->input_lock);
 597         rxrpc_free_skb(skb, rxrpc_skb_freed);
 598         _leave(" [queued]");
 599 }
 600
 601 /*
 602  * See if there's a cached RTT probe to complete.
 603  */
 604 static void rxrpc_complete_rtt_probe(struct rxrpc_call *call,
 605                                      ktime_t resp_time,
 606                                      rxrpc_serial_t acked_serial,
 607                                      rxrpc_serial_t ack_serial,
 608                                      enum rxrpc_rtt_rx_trace type)
 609 {
 610         rxrpc_serial_t orig_serial;
 611         unsigned long avail;
 612         ktime_t sent_at;
 613         bool matched = false;
 614         int i;
 615
 616         avail = READ_ONCE(call->rtt_avail);
 617         smp_rmb(); /* Read avail bits before accessing data. */
 618
 619         for (i = 0; i < ARRAY_SIZE(call->rtt_serial); i++) {
 620                 if (!test_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &avail))
 621                         continue;
 622
 623                 sent_at = call->rtt_sent_at[i];
 624                 orig_serial = call->rtt_serial[i];
 625
 626                 if (orig_serial == acked_serial) {
 627                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 628                         smp_mb(); /* Read data before setting avail bit */
 629                         set_bit(i, &call->rtt_avail);
 630                         if (type != rxrpc_rtt_rx_cancel)
 631                                 rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial,
 632                                                    sent_at, resp_time);
 633                         else
 634                                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_cancel, i,
 635                                                    orig_serial, acked_serial, 0, 0);
 636                         matched = true;
 637                 }
 638
 639                 /* If a later serial is being acked, then mark this slot as
 640                  * being available.
 641                  */
 642                 if (after(acked_serial, orig_serial)) {
 643                         trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_obsolete, i,
 644                                            orig_serial, acked_serial, 0, 0);
 645                         clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 646                         smp_wmb();
 647                         set_bit(i, &call->rtt_avail);
 648                 }
 649         }
 650
 651         if (!matched)
 652                 trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_lost, 9, 0, acked_serial, 0, 0);
 653 }
 654
 655 /*
 656  * Process the response to a ping that we sent to find out if we lost an ACK.
 657  *
 658  * If we got back a ping response that indicates a lower tx_top than what we
 659  * had at the time of the ping transmission, we adjudge all the DATA packets
 660  * sent between the response tx_top and the ping-time tx_top to have been lost.
 661  */
 662 static void rxrpc_input_check_for_lost_ack(struct rxrpc_call *call)
 663 {
 664         struct rxrpc_txbuf *txb;
 665         rxrpc_seq_t top, bottom;
 666         bool resend = false;
 667
 668         bottom = READ_ONCE(call->acks_hard_ack) + 1;
 669         top = READ_ONCE(call->acks_lost_top);
 670         if (before(bottom, top)) {
 671                 list_for_each_entry_rcu(txb, &call->tx_buffer, call_link, false) {
 672                         if (test_bit(RXRPC_TXBUF_ACKED, &txb->flags))
 673                                 continue;
 674                         set_bit(RXRPC_TXBUF_RETRANS, &txb->flags);
 675                         resend = true;
 676                 }
 677         }
 678
 679         if (resend && !test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 680                 rxrpc_queue_call(call);
 681 }
 682
 683 /*
 684  * Process a ping response.
 685  */
 686 static void rxrpc_input_ping_response(struct rxrpc_call *call,
 687                                       ktime_t resp_time,
 688                                       rxrpc_serial_t acked_serial,
 689                                       rxrpc_serial_t ack_serial)
 690 {
 691         if (acked_serial == call->acks_lost_ping)
 692                 rxrpc_input_check_for_lost_ack(call);
 693 }
 694
 695 /*
 696  * Process the extra information that may be appended to an ACK packet
 697  */
 698 static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 699                                 struct rxrpc_ackinfo *ackinfo)
 700 {
 701         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 702         struct rxrpc_peer *peer;
 703         unsigned int mtu;
 704         bool wake = false;
 705         u32 rwind = ntohl(ackinfo->rwind);
 706
 707         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 708                sp->hdr.serial,
 709                ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU),
 710                rwind, ntohl(ackinfo->jumbo_max));
 711
 712         if (rwind > RXRPC_TX_MAX_WINDOW)
 713                 rwind = RXRPC_TX_MAX_WINDOW;
 714         if (call->tx_winsize != rwind) {
 715                 if (rwind > call->tx_winsize)
 716                         wake = true;
 717                 trace_rxrpc_rx_rwind_change(call, sp->hdr.serial, rwind, wake);
 718                 call->tx_winsize = rwind;
 719         }
 720
 721         if (call->cong_ssthresh > rwind)
 722                 call->cong_ssthresh = rwind;
 723
 724         mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));
 725
 726         peer = call->peer;
 727         if (mtu < peer->maxdata) {
 728                 spin_lock_bh(&peer->lock);
 729                 peer->maxdata = mtu;
 730                 peer->mtu = mtu + peer->hdrsize;
 731                 spin_unlock_bh(&peer->lock);
 732                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 733         }
 734
 735         if (wake)
 736                 wake_up(&call->waitq);
 737 }
 738
 739 /*
 740  * Process individual soft ACKs.
 741  *
 742  * Each ACK in the array corresponds to one packet and can be either an ACK or
 743  * a NAK.  If we get find an explicitly NAK'd packet we resend immediately;
 744  * packets that lie beyond the end of the ACK list are scheduled for resend by
 745  * the timer on the basis that the peer might just not have processed them at
 746  * the time the ACK was sent.
 747  */
 748 static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
 749                                   rxrpc_seq_t seq, int nr_acks,
 750                                   struct rxrpc_ack_summary *summary)
 751 {
 752         struct rxrpc_txbuf *txb;
 753
 754         list_for_each_entry_rcu(txb, &call->tx_buffer, call_link, false) {
 755                 if (before(txb->seq, seq))
 756                         continue;
 757                 if (after_eq(txb->seq, seq + nr_acks))
 758                         break;
 759                 switch (acks[txb->seq - seq]) {
 760                 case RXRPC_ACK_TYPE_ACK:
 761                         summary->nr_acks++;
 762                         if (test_bit(RXRPC_TXBUF_ACKED, &txb->flags))
 763                                 continue;
 764                         /* A lot of the time the packet is going to
 765                          * have been ACK.'d already.
 766                          */
 767                         clear_bit(RXRPC_TXBUF_NACKED, &txb->flags);
 768                         set_bit(RXRPC_TXBUF_ACKED, &txb->flags);
 769                         summary->nr_new_acks++;
 770                         break;
 771                 case RXRPC_ACK_TYPE_NACK:
 772                         if (!summary->nr_nacks &&
 773                             call->acks_lowest_nak != seq) {
 774                                 call->acks_lowest_nak = seq;
 775                                 summary->new_low_nack = true;
 776                         }
 777                         summary->nr_nacks++;
 778                         if (test_bit(RXRPC_TXBUF_NACKED, &txb->flags))
 779                                 continue;
 780                         summary->nr_new_nacks++;
 781                         clear_bit(RXRPC_TXBUF_ACKED, &txb->flags);
 782                         set_bit(RXRPC_TXBUF_NACKED, &txb->flags);
 783                         set_bit(RXRPC_TXBUF_RETRANS, &txb->flags);
 784                         break;
 785                 default:
 786                         return rxrpc_proto_abort("SFT", call, 0);
 787                 }
 788         }
 789 }
 790
 791 /*
 792  * Return true if the ACK is valid - ie. it doesn't appear to have regressed
 793  * with respect to the ack state conveyed by preceding ACKs.
 794  */
 795 static bool rxrpc_is_ack_valid(struct rxrpc_call *call,
 796                                rxrpc_seq_t first_pkt, rxrpc_seq_t prev_pkt)
 797 {
 798         rxrpc_seq_t base = READ_ONCE(call->acks_first_seq);
 799
 800         if (after(first_pkt, base))
 801                 return true; /* The window advanced */
 802
 803         if (before(first_pkt, base))
 804                 return false; /* firstPacket regressed */
 805
 806         if (after_eq(prev_pkt, call->acks_prev_seq))
 807                 return true; /* previousPacket hasn't regressed. */
 808
 809         /* Some rx implementations put a serial number in previousPacket. */
 810         if (after_eq(prev_pkt, base + call->tx_winsize))
 811                 return false;
 812         return true;
 813 }
 814
 815 /*
 816  * Process an ACK packet.
 817  *
 818  * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet
 819  * in the ACK array.  Anything before that is hard-ACK'd and may be discarded.
 820  *
 821  * A hard-ACK means that a packet has been processed and may be discarded; a
 822  * soft-ACK means that the packet may be discarded and retransmission
 823  * requested.  A phase is complete when all packets are hard-ACK'd.
 824  */
 825 static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 826 {
 827         struct rxrpc_ack_summary summary = { 0 };
 828         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 829         union {
 830                 struct rxrpc_ackpacket ack;
 831                 struct rxrpc_ackinfo info;
 832                 u8 acks[RXRPC_MAXACKS];
 833         } buf;
 834         rxrpc_serial_t ack_serial, acked_serial;
 835         rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
 836         int nr_acks, offset, ioffset;
 837
 838         _enter("");
 839
 840         offset = sizeof(struct rxrpc_wire_header);
 841         if (skb_copy_bits(skb, offset, &buf.ack, sizeof(buf.ack)) < 0) {
 842                 _debug("extraction failure");
 843                 return rxrpc_proto_abort("XAK", call, 0);
 844         }
 845         offset += sizeof(buf.ack);
 846
 847         ack_serial = sp->hdr.serial;
 848         acked_serial = ntohl(buf.ack.serial);
 849         first_soft_ack = ntohl(buf.ack.firstPacket);
 850         prev_pkt = ntohl(buf.ack.previousPacket);
 851         hard_ack = first_soft_ack - 1;
 852         nr_acks = buf.ack.nAcks;
 853         summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 854                               buf.ack.reason : RXRPC_ACK__INVALID);
 855
 856         trace_rxrpc_rx_ack(call, ack_serial, acked_serial,
 857                            first_soft_ack, prev_pkt,
 858                            summary.ack_reason, nr_acks);
 859         rxrpc_inc_stat(call->rxnet, stat_rx_acks[buf.ack.reason]);
 860
 861         switch (buf.ack.reason) {
 862         case RXRPC_ACK_PING_RESPONSE:
 863                 rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
 864                                           ack_serial);
 865                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 866                                          rxrpc_rtt_rx_ping_response);
 867                 break;
 868         case RXRPC_ACK_REQUESTED:
 869                 rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 870                                          rxrpc_rtt_rx_requested_ack);
 871                 break;
 872         default:
 873                 if (acked_serial != 0)
 874                         rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
 875                                                  rxrpc_rtt_rx_cancel);
 876                 break;
 877         }
 878
 879         if (buf.ack.reason == RXRPC_ACK_PING) {
 880                 _proto("Rx ACK %%%u PING Request", ack_serial);
 881                 rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial,
 882                                rxrpc_propose_ack_respond_to_ping);
 883         } else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 884                 rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, ack_serial,
 885                                rxrpc_propose_ack_respond_to_ack);
 886         }
 887
 888         /* If we get an EXCEEDS_WINDOW ACK from the server, it probably
 889          * indicates that the client address changed due to NAT.  The server
 890          * lost the call because it switched to a different peer.
 891          */
 892         if (unlikely(buf.ack.reason == RXRPC_ACK_EXCEEDS_WINDOW) &&
 893             first_soft_ack == 1 &&
 894             prev_pkt == 0 &&
 895             rxrpc_is_client_call(call)) {
 896                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 897                                           0, -ENETRESET);
 898                 return;
 899         }
 900
 901         /* If we get an OUT_OF_SEQUENCE ACK from the server, that can also
 902          * indicate a change of address.  However, we can retransmit the call
 903          * if we still have it buffered to the beginning.
 904          */
 905         if (unlikely(buf.ack.reason == RXRPC_ACK_OUT_OF_SEQUENCE) &&
 906             first_soft_ack == 1 &&
 907             prev_pkt == 0 &&
 908             call->acks_hard_ack == 0 &&
 909             rxrpc_is_client_call(call)) {
 910                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 911                                           0, -ENETRESET);
 912                 return;
 913         }
 914
 915         /* Discard any out-of-order or duplicate ACKs (outside lock). */
 916         if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 917                 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 918                                            first_soft_ack, call->acks_first_seq,
 919                                            prev_pkt, call->acks_prev_seq);
 920                 return;
 921         }
 922
 923         buf.info.rxMTU = 0;
 924         ioffset = offset + nr_acks + 3;
 925         if (skb->len >= ioffset + sizeof(buf.info) &&
 926             skb_copy_bits(skb, ioffset, &buf.info, sizeof(buf.info)) < 0)
 927                 return rxrpc_proto_abort("XAI", call, 0);
 928
 929         spin_lock(&call->input_lock);
 930
 931         /* Discard any out-of-order or duplicate ACKs (inside lock). */
 932         if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) {
 933                 trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 934                                            first_soft_ack, call->acks_first_seq,
 935                                            prev_pkt, call->acks_prev_seq);
 936                 goto out;
 937         }
 938         call->acks_latest_ts = skb->tstamp;
 939
 940         call->acks_first_seq = first_soft_ack;
 941         call->acks_prev_seq = prev_pkt;
 942
 943         if (buf.ack.reason != RXRPC_ACK_PING &&
 944             after(acked_serial, call->acks_highest_serial))
 945                 call->acks_highest_serial = acked_serial;
 946
 947         /* Parse rwind and mtu sizes if provided. */
 948         if (buf.info.rxMTU)
 949                 rxrpc_input_ackinfo(call, skb, &buf.info);
 950
 951         if (first_soft_ack == 0) {
 952                 rxrpc_proto_abort("AK0", call, 0);
 953                 goto out;
 954         }
 955
 956         /* Ignore ACKs unless we are or have just been transmitting. */
 957         switch (READ_ONCE(call->state)) {
 958         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 959         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 960         case RXRPC_CALL_SERVER_SEND_REPLY:
 961         case RXRPC_CALL_SERVER_AWAIT_ACK:
 962                 break;
 963         default:
 964                 goto out;
 965         }
 966
 967         if (before(hard_ack, call->acks_hard_ack) ||
 968             after(hard_ack, call->tx_top)) {
 969                 rxrpc_proto_abort("AKW", call, 0);
 970                 goto out;
 971         }
 972         if (nr_acks > call->tx_top - hard_ack) {
 973                 rxrpc_proto_abort("AKN", call, 0);
 974                 goto out;
 975         }
 976
 977         if (after(hard_ack, call->acks_hard_ack)) {
 978                 if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
 979                         rxrpc_end_tx_phase(call, false, "ETA");
 980                         goto out;
 981                 }
 982         }
 983
 984         if (nr_acks > 0) {
 985                 if (skb_copy_bits(skb, offset, buf.acks, nr_acks) < 0) {
 986                         rxrpc_proto_abort("XSA", call, 0);
 987                         goto out;
 988                 }
 989                 rxrpc_input_soft_acks(call, buf.acks, first_soft_ack, nr_acks,
 990                                       &summary);
 991         }
 992
 993         if (test_bit(RXRPC_CALL_TX_LAST, &call->flags) &&
 994             summary.nr_acks == call->tx_top - hard_ack &&
 995             rxrpc_is_client_call(call))
 996                 rxrpc_propose_ping(call, ack_serial,
 997                                    rxrpc_propose_ack_ping_for_lost_reply);
 998
 999         rxrpc_congestion_management(call, skb, &summary, acked_serial);
1000 out:
1001         spin_unlock(&call->input_lock);
1002 }
1003
1004 /*
1005  * Process an ACKALL packet.
1006  */
1007 static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
1008 {
1009         struct rxrpc_ack_summary summary = { 0 };
1010         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1011
1012         _proto("Rx ACKALL %%%u", sp->hdr.serial);
1013
1014         spin_lock(&call->input_lock);
1015
1016         if (rxrpc_rotate_tx_window(call, call->tx_top, &summary))
1017                 rxrpc_end_tx_phase(call, false, "ETL");
1018
1019         spin_unlock(&call->input_lock);
1020 }
1021
1022 /*
1023  * Process an ABORT packet directed at a call.
1024  */
1025 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
1026 {
1027         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1028         __be32 wtmp;
1029         u32 abort_code = RX_CALL_DEAD;
1030
1031         _enter("");
1032
1033         if (skb->len >= 4 &&
1034             skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
1035                           &wtmp, sizeof(wtmp)) >= 0)
1036                 abort_code = ntohl(wtmp);
1037
1038         trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
1039
1040         _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
1041
1042         rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
1043                                   abort_code, -ECONNABORTED);
1044 }
1045
1046 /*
1047  * Process an incoming call packet.
1048  */
1049 static void rxrpc_input_call_packet(struct rxrpc_call *call,
1050                                     struct sk_buff *skb)
1051 {
1052         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
1053         unsigned long timo;
1054
1055         _enter("%p,%p", call, skb);
1056
1057         timo = READ_ONCE(call->next_rx_timo);
1058         if (timo) {
1059                 unsigned long now = jiffies, expect_rx_by;
1060
1061                 expect_rx_by = now + timo;
1062                 WRITE_ONCE(call->expect_rx_by, expect_rx_by);
1063                 rxrpc_reduce_call_timer(call, expect_rx_by, now,
1064                                         rxrpc_timer_set_for_normal);
1065         }
1066
1067         switch (sp->hdr.type) {
1068         case RXRPC_PACKET_TYPE_DATA:
1069                 rxrpc_input_data(call, skb);
1070                 goto no_free;
1071
1072         case RXRPC_PACKET_TYPE_ACK:
1073                 rxrpc_input_ack(call, skb);
1074                 break;
1075
1076         case RXRPC_PACKET_TYPE_BUSY:
1077                 _proto("Rx BUSY %%%u", sp->hdr.serial);
1078
1079                 /* Just ignore BUSY packets from the server; the retry and
1080                  * lifespan timers will take care of business.  BUSY packets
1081                  * from the client don't make sense.
1082                  */
1083                 break;
1084
1085         case RXRPC_PACKET_TYPE_ABORT:
1086                 rxrpc_input_abort(call, skb);
1087                 break;
1088
1089         case RXRPC_PACKET_TYPE_ACKALL:
1090                 rxrpc_input_ackall(call, skb);
1091                 break;
1092
1093         default:
1094                 break;
1095         }
1096
1097         rxrpc_free_skb(skb, rxrpc_skb_freed);
1098 no_free:
1099         _leave("");
1100 }
1101
1102 /*
1103  * Handle a new service call on a channel implicitly completing the preceding
1104  * call on that channel.  This does not apply to client conns.
1105  *
1106  * TODO: If callNumber > call_id + 1, renegotiate security.
1107  */
1108 static void rxrpc_input_implicit_end_call(struct rxrpc_sock *rx,
1109                                           struct rxrpc_connection *conn,
1110                                           struct rxrpc_call *call)
1111 {
1112         switch (READ_ONCE(call->state)) {
1113         case RXRPC_CALL_SERVER_AWAIT_ACK:
1114                 rxrpc_call_completed(call);
1115                 fallthrough;
1116         case RXRPC_CALL_COMPLETE:
1117                 break;
1118         default:
1119                 if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, -ESHUTDOWN)) {
1120                         set_bit(RXRPC_CALL_EV_ABORT, &call->events);
1121                         rxrpc_queue_call(call);
1122                 }
1123                 trace_rxrpc_improper_term(call);
1124                 break;
1125         }
1126
1127         spin_lock(&rx->incoming_lock);
1128         __rxrpc_disconnect_call(conn, call);
1129         spin_unlock(&rx->incoming_lock);
1130 }
1131
1132 /*
1133  * post connection-level events to the connection
1134  * - this includes challenges, responses, some aborts and call terminal packet
1135  *   retransmission.
1136  */
1137 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
1138                                       struct sk_buff *skb)
1139 {
1140         _enter("%p,%p", conn, skb);
1141
1142         skb_queue_tail(&conn->rx_queue, skb);
1143         rxrpc_queue_conn(conn);
1144 }
1145
1146 /*
1147  * post endpoint-level events to the local endpoint
1148  * - this includes debug and version messages
1149  */
1150 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
1151                                        struct sk_buff *skb)
1152 {
1153         _enter("%p,%p", local, skb);
1154
1155         if (rxrpc_get_local_maybe(local)) {
1156                 skb_queue_tail(&local->event_queue, skb);
1157                 rxrpc_queue_local(local);
1158         } else {
1159                 rxrpc_free_skb(skb, rxrpc_skb_freed);
1160         }
1161 }
1162
1163 /*
1164  * put a packet up for transport-level abort
1165  */
1166 static void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
1167 {
1168         if (rxrpc_get_local_maybe(local)) {
1169                 skb_queue_tail(&local->reject_queue, skb);
1170                 rxrpc_queue_local(local);
1171         } else {
1172                 rxrpc_free_skb(skb, rxrpc_skb_freed);
1173         }
1174 }
1175
1176 /*
1177  * Extract the wire header from a packet and translate the byte order.
1178  */
1179 static noinline
1180 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
1181 {
1182         struct rxrpc_wire_header whdr;
1183
1184         /* dig out the RxRPC connection details */
1185         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0) {
1186                 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
1187                                       tracepoint_string("bad_hdr"));
1188                 return -EBADMSG;
1189         }
1190
1191         memset(sp, 0, sizeof(*sp));
1192         sp->hdr.epoch           = ntohl(whdr.epoch);
1193         sp->hdr.cid             = ntohl(whdr.cid);
1194         sp->hdr.callNumber      = ntohl(whdr.callNumber);
1195         sp->hdr.seq             = ntohl(whdr.seq);
1196         sp->hdr.serial          = ntohl(whdr.serial);
1197         sp->hdr.flags           = whdr.flags;
1198         sp->hdr.type            = whdr.type;
1199         sp->hdr.userStatus      = whdr.userStatus;
1200         sp->hdr.securityIndex   = whdr.securityIndex;
1201         sp->hdr._rsvd           = ntohs(whdr._rsvd);
1202         sp->hdr.serviceId       = ntohs(whdr.serviceId);
1203         return 0;
1204 }
1205
1206 /*
1207  * handle data received on the local endpoint
1208  * - may be called in interrupt context
1209  *
1210  * [!] Note that as this is called from the encap_rcv hook, the socket is not
1211  * held locked by the caller and nothing prevents sk_user_data on the UDP from
1212  * being cleared in the middle of processing this function.
1213  *
1214  * Called with the RCU read lock held from the IP layer via UDP.
1215  */
1216 int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
1217 {
1218         struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
1219         struct rxrpc_connection *conn;
1220         struct rxrpc_channel *chan;
1221         struct rxrpc_call *call = NULL;
1222         struct rxrpc_skb_priv *sp;
1223         struct rxrpc_peer *peer = NULL;
1224         struct rxrpc_sock *rx = NULL;
1225         unsigned int channel;
1226
1227         _enter("%p", udp_sk);
1228
1229         if (unlikely(!local)) {
1230                 kfree_skb(skb);
1231                 return 0;
1232         }
1233         if (skb->tstamp == 0)
1234                 skb->tstamp = ktime_get_real();
1235
1236         rxrpc_new_skb(skb, rxrpc_skb_received);
1237
1238         skb_pull(skb, sizeof(struct udphdr));
1239
1240         /* The UDP protocol already released all skb resources;
1241          * we are free to add our own data there.
1242          */
1243         sp = rxrpc_skb(skb);
1244
1245         /* dig out the RxRPC connection details */
1246         if (rxrpc_extract_header(sp, skb) < 0)
1247                 goto bad_message;
1248
1249         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
1250                 static int lose;
1251                 if ((lose++ & 7) == 7) {
1252                         trace_rxrpc_rx_lose(sp);
1253                         rxrpc_free_skb(skb, rxrpc_skb_lost);
1254                         return 0;
1255                 }
1256         }
1257
1258         if (skb->tstamp == 0)
1259                 skb->tstamp = ktime_get_real();
1260         trace_rxrpc_rx_packet(sp);
1261
1262         switch (sp->hdr.type) {
1263         case RXRPC_PACKET_TYPE_VERSION:
1264                 if (rxrpc_to_client(sp))
1265                         goto discard;
1266                 rxrpc_post_packet_to_local(local, skb);
1267                 goto out;
1268
1269         case RXRPC_PACKET_TYPE_BUSY:
1270                 if (rxrpc_to_server(sp))
1271                         goto discard;
1272                 fallthrough;
1273         case RXRPC_PACKET_TYPE_ACK:
1274         case RXRPC_PACKET_TYPE_ACKALL:
1275                 if (sp->hdr.callNumber == 0)
1276                         goto bad_message;
1277                 fallthrough;
1278         case RXRPC_PACKET_TYPE_ABORT:
1279                 break;
1280
1281         case RXRPC_PACKET_TYPE_DATA:
1282                 if (sp->hdr.callNumber == 0 ||
1283                     sp->hdr.seq == 0)
1284                         goto bad_message;
1285
1286                 /* Unshare the packet so that it can be modified for in-place
1287                  * decryption.
1288                  */
1289                 if (sp->hdr.securityIndex != 0) {
1290                         struct sk_buff *nskb = skb_unshare(skb, GFP_ATOMIC);
1291                         if (!nskb) {
1292                                 rxrpc_eaten_skb(skb, rxrpc_skb_unshared_nomem);
1293                                 goto out;
1294                         }
1295
1296                         if (nskb != skb) {
1297                                 rxrpc_eaten_skb(skb, rxrpc_skb_received);
1298                                 skb = nskb;
1299                                 rxrpc_new_skb(skb, rxrpc_skb_unshared);
1300                                 sp = rxrpc_skb(skb);
1301                         }
1302                 }
1303                 break;
1304
1305         case RXRPC_PACKET_TYPE_CHALLENGE:
1306                 if (rxrpc_to_server(sp))
1307                         goto discard;
1308                 break;
1309         case RXRPC_PACKET_TYPE_RESPONSE:
1310                 if (rxrpc_to_client(sp))
1311                         goto discard;
1312                 break;
1313
1314                 /* Packet types 9-11 should just be ignored. */
1315         case RXRPC_PACKET_TYPE_PARAMS:
1316         case RXRPC_PACKET_TYPE_10:
1317         case RXRPC_PACKET_TYPE_11:
1318                 goto discard;
1319
1320         default:
1321                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
1322                 goto bad_message;
1323         }
1324
1325         if (sp->hdr.serviceId == 0)
1326                 goto bad_message;
1327
1328         if (rxrpc_to_server(sp)) {
1329                 /* Weed out packets to services we're not offering.  Packets
1330                  * that would begin a call are explicitly rejected and the rest
1331                  * are just discarded.
1332                  */
1333                 rx = rcu_dereference(local->service);
1334                 if (!rx || (sp->hdr.serviceId != rx->srx.srx_service &&
1335                             sp->hdr.serviceId != rx->second_service)) {
1336                         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
1337                             sp->hdr.seq == 1)
1338                                 goto unsupported_service;
1339                         goto discard;
1340                 }
1341         }
1342
1343         conn = rxrpc_find_connection_rcu(local, skb, &peer);
1344         if (conn) {
1345                 if (sp->hdr.securityIndex != conn->security_ix)
1346                         goto wrong_security;
1347
1348                 if (sp->hdr.serviceId != conn->service_id) {
1349                         int old_id;
1350
1351                         if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags))
1352                                 goto reupgrade;
1353                         old_id = cmpxchg(&conn->service_id, conn->params.service_id,
1354                                          sp->hdr.serviceId);
1355
1356                         if (old_id != conn->params.service_id &&
1357                             old_id != sp->hdr.serviceId)
1358                                 goto reupgrade;
1359                 }
1360
1361                 if (sp->hdr.callNumber == 0) {
1362                         /* Connection-level packet */
1363                         _debug("CONN %p {%d}", conn, conn->debug_id);
1364                         rxrpc_post_packet_to_conn(conn, skb);
1365                         goto out;
1366                 }
1367
1368                 if ((int)sp->hdr.serial - (int)conn->hi_serial > 0)
1369                         conn->hi_serial = sp->hdr.serial;
1370
1371                 /* Call-bound packets are routed by connection channel. */
1372                 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
1373                 chan = &conn->channels[channel];
1374
1375                 /* Ignore really old calls */
1376                 if (sp->hdr.callNumber < chan->last_call)
1377                         goto discard;
1378
1379                 if (sp->hdr.callNumber == chan->last_call) {
1380                         if (chan->call ||
1381                             sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
1382                                 goto discard;
1383
1384                         /* For the previous service call, if completed
1385                          * successfully, we discard all further packets.
1386                          */
1387                         if (rxrpc_conn_is_service(conn) &&
1388                             chan->last_type == RXRPC_PACKET_TYPE_ACK)
1389                                 goto discard;
1390
1391                         /* But otherwise we need to retransmit the final packet
1392                          * from data cached in the connection record.
1393                          */
1394                         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
1395                                 trace_rxrpc_rx_data(chan->call_debug_id,
1396                                                     sp->hdr.seq,
1397                                                     sp->hdr.serial,
1398                                                     sp->hdr.flags);
1399                         rxrpc_post_packet_to_conn(conn, skb);
1400                         goto out;
1401                 }
1402
1403                 call = rcu_dereference(chan->call);
1404
1405                 if (sp->hdr.callNumber > chan->call_id) {
1406                         if (rxrpc_to_client(sp))
1407                                 goto reject_packet;
1408                         if (call)
1409                                 rxrpc_input_implicit_end_call(rx, conn, call);
1410                         call = NULL;
1411                 }
1412
1413                 if (call) {
1414                         if (sp->hdr.serviceId != call->service_id)
1415                                 call->service_id = sp->hdr.serviceId;
1416                         if ((int)sp->hdr.serial - (int)call->rx_serial > 0)
1417                                 call->rx_serial = sp->hdr.serial;
1418                         if (!test_bit(RXRPC_CALL_RX_HEARD, &call->flags))
1419                                 set_bit(RXRPC_CALL_RX_HEARD, &call->flags);
1420                 }
1421         }
1422
1423         if (!call || refcount_read(&call->ref) == 0) {
1424                 if (rxrpc_to_client(sp) ||
1425                     sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
1426                         goto bad_message;
1427                 if (sp->hdr.seq != 1)
1428                         goto discard;
1429                 call = rxrpc_new_incoming_call(local, rx, skb);
1430                 if (!call)
1431                         goto reject_packet;
1432         }
1433
1434         /* Process a call packet; this either discards or passes on the ref
1435          * elsewhere.
1436          */
1437         rxrpc_input_call_packet(call, skb);
1438         goto out;
1439
1440 discard:
1441         rxrpc_free_skb(skb, rxrpc_skb_freed);
1442 out:
1443         trace_rxrpc_rx_done(0, 0);
1444         return 0;
1445
1446 wrong_security:
1447         trace_rxrpc_abort(0, "SEC", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1448                           RXKADINCONSISTENCY, EBADMSG);
1449         skb->priority = RXKADINCONSISTENCY;
1450         goto post_abort;
1451
1452 unsupported_service:
1453         trace_rxrpc_abort(0, "INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1454                           RX_INVALID_OPERATION, EOPNOTSUPP);
1455         skb->priority = RX_INVALID_OPERATION;
1456         goto post_abort;
1457
1458 reupgrade:
1459         trace_rxrpc_abort(0, "UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1460                           RX_PROTOCOL_ERROR, EBADMSG);
1461         goto protocol_error;
1462
1463 bad_message:
1464         trace_rxrpc_abort(0, "BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
1465                           RX_PROTOCOL_ERROR, EBADMSG);
1466 protocol_error:
1467         skb->priority = RX_PROTOCOL_ERROR;
1468 post_abort:
1469         skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
1470 reject_packet:
1471         trace_rxrpc_rx_done(skb->mark, skb->priority);
1472         rxrpc_reject_packet(local, skb);
1473         _leave(" [badmsg]");
1474         return 0;
1475 }