net/rxrpc/input.c

   1 /* RxRPC packet reception
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/net.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/errqueue.h>
  18 #include <linux/udp.h>
  19 #include <linux/in.h>
  20 #include <linux/in6.h>
  21 #include <linux/icmp.h>
  22 #include <linux/gfp.h>
  23 #include <net/sock.h>
  24 #include <net/af_rxrpc.h>
  25 #include <net/ip.h>
  26 #include <net/udp.h>
  27 #include <net/net_namespace.h>
  28 #include "ar-internal.h"
  29
  30 /*
  31  * queue a packet for recvmsg to pass to userspace
  32  * - the caller must hold a lock on call->lock
  33  * - must not be called with interrupts disabled (sk_filter() disables BH's)
  34  * - eats the packet whether successful or not
  35  * - there must be just one reference to the packet, which the caller passes to
  36  *   this function
  37  */
  38 int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
  39                         bool force, bool terminal)
  40 {
  41         struct rxrpc_skb_priv *sp;
  42         struct rxrpc_sock *rx = call->socket;
  43         struct sock *sk;
  44         int ret;
  45
  46         _enter(",,%d,%d", force, terminal);
  47
  48         ASSERT(!irqs_disabled());
  49
  50         sp = rxrpc_skb(skb);
  51         ASSERTCMP(sp->call, ==, call);
  52
  53         /* if we've already posted the terminal message for a call, then we
  54          * don't post any more */
  55         if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
  56                 _debug("already terminated");
  57                 ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
  58                 rxrpc_free_skb(skb);
  59                 return 0;
  60         }
  61
  62         sk = &rx->sk;
  63
  64         if (!force) {
  65                 /* cast skb->rcvbuf to unsigned...  It's pointless, but
  66                  * reduces number of warnings when compiling with -W
  67                  * --ANK */
  68 //              ret = -ENOBUFS;
  69 //              if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
  70 //                  (unsigned int) sk->sk_rcvbuf)
  71 //                      goto out;
  72
  73                 ret = sk_filter(sk, skb);
  74                 if (ret < 0)
  75                         goto out;
  76         }
  77
  78         spin_lock_bh(&sk->sk_receive_queue.lock);
  79         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
  80             !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
  81             call->socket->sk.sk_state != RXRPC_CLOSE) {
  82                 skb->destructor = rxrpc_packet_destructor;
  83                 skb->dev = NULL;
  84                 skb->sk = sk;
  85                 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
  86
  87                 if (terminal) {
  88                         _debug("<<<< TERMINAL MESSAGE >>>>");
  89                         set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
  90                 }
  91
  92                 /* allow interception by a kernel service */
  93                 if (skb->mark == RXRPC_SKB_MARK_NEW_CALL &&
  94                     rx->notify_new_call) {
  95                         spin_unlock_bh(&sk->sk_receive_queue.lock);
  96                         skb_queue_tail(&call->knlrecv_queue, skb);
  97                         rx->notify_new_call(&rx->sk);
  98                 } else if (call->notify_rx) {
  99                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 100                         skb_queue_tail(&call->knlrecv_queue, skb);
 101                         call->notify_rx(&rx->sk, call, call->user_call_ID);
 102                 } else {
 103                         _net("post skb %p", skb);
 104                         __skb_queue_tail(&sk->sk_receive_queue, skb);
 105                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 106
 107                         if (!sock_flag(sk, SOCK_DEAD))
 108                                 sk->sk_data_ready(sk);
 109                 }
 110                 skb = NULL;
 111         } else {
 112                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 113         }
 114         ret = 0;
 115
 116 out:
 117         rxrpc_free_skb(skb);
 118
 119         _leave(" = %d", ret);
 120         return ret;
 121 }
 122
 123 /*
 124  * process a DATA packet, posting the packet to the appropriate queue
 125  * - eats the packet if successful
 126  */
 127 static int rxrpc_fast_process_data(struct rxrpc_call *call,
 128                                    struct sk_buff *skb, u32 seq)
 129 {
 130         struct rxrpc_skb_priv *sp;
 131         bool terminal;
 132         int ret, ackbit, ack;
 133         u32 serial;
 134         u16 skew;
 135         u8 flags;
 136
 137         _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
 138
 139         sp = rxrpc_skb(skb);
 140         ASSERTCMP(sp->call, ==, NULL);
 141         flags = sp->hdr.flags;
 142         serial = sp->hdr.serial;
 143         skew = skb->priority;
 144
 145         spin_lock(&call->lock);
 146
 147         if (call->state > RXRPC_CALL_COMPLETE)
 148                 goto discard;
 149
 150         ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
 151         ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
 152         ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
 153
 154         if (seq < call->rx_data_post) {
 155                 _debug("dup #%u [-%u]", seq, call->rx_data_post);
 156                 ack = RXRPC_ACK_DUPLICATE;
 157                 ret = -ENOBUFS;
 158                 goto discard_and_ack;
 159         }
 160
 161         /* we may already have the packet in the out of sequence queue */
 162         ackbit = seq - (call->rx_data_eaten + 1);
 163         ASSERTCMP(ackbit, >=, 0);
 164         if (__test_and_set_bit(ackbit, call->ackr_window)) {
 165                 _debug("dup oos #%u [%u,%u]",
 166                        seq, call->rx_data_eaten, call->rx_data_post);
 167                 ack = RXRPC_ACK_DUPLICATE;
 168                 goto discard_and_ack;
 169         }
 170
 171         if (seq >= call->ackr_win_top) {
 172                 _debug("exceed #%u [%u]", seq, call->ackr_win_top);
 173                 __clear_bit(ackbit, call->ackr_window);
 174                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 175                 goto discard_and_ack;
 176         }
 177
 178         if (seq == call->rx_data_expect) {
 179                 clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
 180                 call->rx_data_expect++;
 181         } else if (seq > call->rx_data_expect) {
 182                 _debug("oos #%u [%u]", seq, call->rx_data_expect);
 183                 call->rx_data_expect = seq + 1;
 184                 if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
 185                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 186                         goto enqueue_and_ack;
 187                 }
 188                 goto enqueue_packet;
 189         }
 190
 191         if (seq != call->rx_data_post) {
 192                 _debug("ahead #%u [%u]", seq, call->rx_data_post);
 193                 goto enqueue_packet;
 194         }
 195
 196         if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
 197                 goto protocol_error;
 198
 199         /* if the packet need security things doing to it, then it goes down
 200          * the slow path */
 201         if (call->security_ix)
 202                 goto enqueue_packet;
 203
 204         sp->call = call;
 205         rxrpc_get_call_for_skb(call, skb);
 206         terminal = ((flags & RXRPC_LAST_PACKET) &&
 207                     !(flags & RXRPC_CLIENT_INITIATED));
 208         ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
 209         if (ret < 0) {
 210                 if (ret == -ENOMEM || ret == -ENOBUFS) {
 211                         __clear_bit(ackbit, call->ackr_window);
 212                         ack = RXRPC_ACK_NOSPACE;
 213                         goto discard_and_ack;
 214                 }
 215                 goto out;
 216         }
 217
 218         skb = NULL;
 219         sp = NULL;
 220
 221         _debug("post #%u", seq);
 222         ASSERTCMP(call->rx_data_post, ==, seq);
 223         call->rx_data_post++;
 224
 225         if (flags & RXRPC_LAST_PACKET)
 226                 set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);
 227
 228         /* if we've reached an out of sequence packet then we need to drain
 229          * that queue into the socket Rx queue now */
 230         if (call->rx_data_post == call->rx_first_oos) {
 231                 _debug("drain rx oos now");
 232                 read_lock(&call->state_lock);
 233                 if (call->state < RXRPC_CALL_COMPLETE &&
 234                     !test_and_set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events))
 235                         rxrpc_queue_call(call);
 236                 read_unlock(&call->state_lock);
 237         }
 238
 239         spin_unlock(&call->lock);
 240         atomic_inc(&call->ackr_not_idle);
 241         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, skew, serial, false);
 242         _leave(" = 0 [posted]");
 243         return 0;
 244
 245 protocol_error:
 246         ret = -EBADMSG;
 247 out:
 248         spin_unlock(&call->lock);
 249         _leave(" = %d", ret);
 250         return ret;
 251
 252 discard_and_ack:
 253         _debug("discard and ACK packet %p", skb);
 254         __rxrpc_propose_ACK(call, ack, skew, serial, true);
 255 discard:
 256         spin_unlock(&call->lock);
 257         rxrpc_free_skb(skb);
 258         _leave(" = 0 [discarded]");
 259         return 0;
 260
 261 enqueue_and_ack:
 262         __rxrpc_propose_ACK(call, ack, skew, serial, true);
 263 enqueue_packet:
 264         _net("defer skb %p", skb);
 265         spin_unlock(&call->lock);
 266         skb_queue_tail(&call->rx_queue, skb);
 267         atomic_inc(&call->ackr_not_idle);
 268         read_lock(&call->state_lock);
 269         if (call->state < RXRPC_CALL_DEAD)
 270                 rxrpc_queue_call(call);
 271         read_unlock(&call->state_lock);
 272         _leave(" = 0 [queued]");
 273         return 0;
 274 }
 275
 276 /*
 277  * assume an implicit ACKALL of the transmission phase of a client socket upon
 278  * reception of the first reply packet
 279  */
 280 static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
 281 {
 282         write_lock_bh(&call->state_lock);
 283
 284         switch (call->state) {
 285         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 286                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 287                 call->acks_latest = serial;
 288
 289                 _debug("implicit ACKALL %%%u", call->acks_latest);
 290                 set_bit(RXRPC_CALL_EV_RCVD_ACKALL, &call->events);
 291                 write_unlock_bh(&call->state_lock);
 292
 293                 if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
 294                         clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
 295                         clear_bit(RXRPC_CALL_EV_RESEND, &call->events);
 296                         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 297                 }
 298                 break;
 299
 300         default:
 301                 write_unlock_bh(&call->state_lock);
 302                 break;
 303         }
 304 }
 305
 306 /*
 307  * post an incoming packet to the nominated call to deal with
 308  * - must get rid of the sk_buff, either by freeing it or by queuing it
 309  */
 310 void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
 311 {
 312         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 313         __be32 wtmp;
 314         u32 abort_code;
 315
 316         _enter("%p,%p", call, skb);
 317
 318         ASSERT(!irqs_disabled());
 319
 320 #if 0 // INJECT RX ERROR
 321         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 322                 static int skip = 0;
 323                 if (++skip == 3) {
 324                         printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
 325                         skip = 0;
 326                         goto free_packet;
 327                 }
 328         }
 329 #endif
 330
 331         /* request ACK generation for any ACK or DATA packet that requests
 332          * it */
 333         if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 334                 _proto("ACK Requested on %%%u", sp->hdr.serial);
 335                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 336                                   skb->priority, sp->hdr.serial, false);
 337         }
 338
 339         switch (sp->hdr.type) {
 340         case RXRPC_PACKET_TYPE_ABORT:
 341                 _debug("abort");
 342
 343                 if (skb_copy_bits(skb, 0, &wtmp, sizeof(wtmp)) < 0)
 344                         goto protocol_error;
 345
 346                 abort_code = ntohl(wtmp);
 347                 _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 348
 349                 if (__rxrpc_set_call_completion(call,
 350                                                 RXRPC_CALL_REMOTELY_ABORTED,
 351                                                 abort_code, ECONNABORTED)) {
 352                         set_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
 353                         rxrpc_queue_call(call);
 354                 }
 355                 goto free_packet;
 356
 357         case RXRPC_PACKET_TYPE_BUSY:
 358                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 359
 360                 if (rxrpc_is_service_call(call))
 361                         goto protocol_error;
 362
 363                 write_lock_bh(&call->state_lock);
 364                 switch (call->state) {
 365                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 366                         __rxrpc_set_call_completion(call,
 367                                                     RXRPC_CALL_SERVER_BUSY,
 368                                                     0, EBUSY);
 369                         set_bit(RXRPC_CALL_EV_RCVD_BUSY, &call->events);
 370                         rxrpc_queue_call(call);
 371                 case RXRPC_CALL_SERVER_BUSY:
 372                         goto free_packet_unlock;
 373                 default:
 374                         goto protocol_error_locked;
 375                 }
 376
 377         default:
 378                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 379                 goto protocol_error;
 380
 381         case RXRPC_PACKET_TYPE_DATA:
 382                 _proto("Rx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
 383
 384                 if (sp->hdr.seq == 0)
 385                         goto protocol_error;
 386
 387                 call->ackr_prev_seq = sp->hdr.seq;
 388
 389                 /* received data implicitly ACKs all of the request packets we
 390                  * sent when we're acting as a client */
 391                 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 392                         rxrpc_assume_implicit_ackall(call, sp->hdr.serial);
 393
 394                 switch (rxrpc_fast_process_data(call, skb, sp->hdr.seq)) {
 395                 case 0:
 396                         skb = NULL;
 397                         goto done;
 398
 399                 default:
 400                         BUG();
 401
 402                         /* data packet received beyond the last packet */
 403                 case -EBADMSG:
 404                         goto protocol_error;
 405                 }
 406
 407         case RXRPC_PACKET_TYPE_ACKALL:
 408         case RXRPC_PACKET_TYPE_ACK:
 409                 /* ACK processing is done in process context */
 410                 read_lock_bh(&call->state_lock);
 411                 if (call->state < RXRPC_CALL_DEAD) {
 412                         skb_queue_tail(&call->rx_queue, skb);
 413                         rxrpc_queue_call(call);
 414                         skb = NULL;
 415                 }
 416                 read_unlock_bh(&call->state_lock);
 417                 goto free_packet;
 418         }
 419
 420 protocol_error:
 421         _debug("protocol error");
 422         write_lock_bh(&call->state_lock);
 423 protocol_error_locked:
 424         if (__rxrpc_abort_call(call, RX_PROTOCOL_ERROR, EPROTO))
 425                 rxrpc_queue_call(call);
 426 free_packet_unlock:
 427         write_unlock_bh(&call->state_lock);
 428 free_packet:
 429         rxrpc_free_skb(skb);
 430 done:
 431         _leave("");
 432 }
 433
 434 /*
 435  * split up a jumbo data packet
 436  */
 437 static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
 438                                        struct sk_buff *jumbo)
 439 {
 440         struct rxrpc_jumbo_header jhdr;
 441         struct rxrpc_skb_priv *sp;
 442         struct sk_buff *part;
 443
 444         _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
 445
 446         sp = rxrpc_skb(jumbo);
 447
 448         do {
 449                 sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
 450
 451                 /* make a clone to represent the first subpacket in what's left
 452                  * of the jumbo packet */
 453                 part = skb_clone(jumbo, GFP_ATOMIC);
 454                 if (!part) {
 455                         /* simply ditch the tail in the event of ENOMEM */
 456                         pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
 457                         break;
 458                 }
 459                 rxrpc_new_skb(part);
 460
 461                 pskb_trim(part, RXRPC_JUMBO_DATALEN);
 462
 463                 if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
 464                         goto protocol_error;
 465
 466                 if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
 467                         goto protocol_error;
 468                 if (!pskb_pull(jumbo, sizeof(jhdr)))
 469                         BUG();
 470
 471                 sp->hdr.seq     += 1;
 472                 sp->hdr.serial  += 1;
 473                 sp->hdr.flags   = jhdr.flags;
 474                 sp->hdr._rsvd   = ntohs(jhdr._rsvd);
 475
 476                 _proto("Rx DATA Jumbo %%%u", sp->hdr.serial - 1);
 477
 478                 rxrpc_fast_process_packet(call, part);
 479                 part = NULL;
 480
 481         } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
 482
 483         rxrpc_fast_process_packet(call, jumbo);
 484         _leave("");
 485         return;
 486
 487 protocol_error:
 488         _debug("protocol error");
 489         rxrpc_free_skb(part);
 490         rxrpc_free_skb(jumbo);
 491         if (rxrpc_abort_call(call, RX_PROTOCOL_ERROR, EPROTO))
 492                 rxrpc_queue_call(call);
 493         _leave("");
 494 }
 495
 496 /*
 497  * post an incoming packet to the appropriate call/socket to deal with
 498  * - must get rid of the sk_buff, either by freeing it or by queuing it
 499  */
 500 static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
 501                                       struct rxrpc_call *call,
 502                                       struct sk_buff *skb)
 503 {
 504         struct rxrpc_skb_priv *sp;
 505
 506         _enter("%p,%p", call, skb);
 507
 508         sp = rxrpc_skb(skb);
 509
 510         _debug("extant call [%d]", call->state);
 511
 512         read_lock(&call->state_lock);
 513         switch (call->state) {
 514         case RXRPC_CALL_DEAD:
 515                 goto dead_call;
 516
 517         case RXRPC_CALL_COMPLETE:
 518                 switch (call->completion) {
 519                 case RXRPC_CALL_LOCALLY_ABORTED:
 520                         if (!test_and_set_bit(RXRPC_CALL_EV_ABORT,
 521                                               &call->events)) {
 522                                 rxrpc_queue_call(call);
 523                                 goto free_unlock;
 524                         }
 525                 default:
 526                         goto dead_call;
 527                 case RXRPC_CALL_SUCCEEDED:
 528                         if (rxrpc_is_service_call(call))
 529                                 goto dead_call;
 530                         goto resend_final_ack;
 531                 }
 532
 533         case RXRPC_CALL_CLIENT_FINAL_ACK:
 534                 goto resend_final_ack;
 535
 536         default:
 537                 break;
 538         }
 539
 540         read_unlock(&call->state_lock);
 541         rxrpc_get_call(call, rxrpc_call_got);
 542
 543         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 544             sp->hdr.flags & RXRPC_JUMBO_PACKET)
 545                 rxrpc_process_jumbo_packet(call, skb);
 546         else
 547                 rxrpc_fast_process_packet(call, skb);
 548
 549         rxrpc_put_call(call, rxrpc_call_put);
 550         goto done;
 551
 552 resend_final_ack:
 553         _debug("final ack again");
 554         rxrpc_get_call(call, rxrpc_call_got);
 555         set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
 556         rxrpc_queue_call(call);
 557         goto free_unlock;
 558
 559 dead_call:
 560         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 561                 skb->priority = RX_CALL_DEAD;
 562                 rxrpc_reject_packet(conn->params.local, skb);
 563                 goto unlock;
 564         }
 565 free_unlock:
 566         rxrpc_free_skb(skb);
 567 unlock:
 568         read_unlock(&call->state_lock);
 569 done:
 570         _leave("");
 571 }
 572
 573 /*
 574  * post connection-level events to the connection
 575  * - this includes challenges, responses, some aborts and call terminal packet
 576  *   retransmission.
 577  */
 578 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 579                                       struct sk_buff *skb)
 580 {
 581         _enter("%p,%p", conn, skb);
 582
 583         skb_queue_tail(&conn->rx_queue, skb);
 584         rxrpc_queue_conn(conn);
 585 }
 586
 587 /*
 588  * post endpoint-level events to the local endpoint
 589  * - this includes debug and version messages
 590  */
 591 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 592                                        struct sk_buff *skb)
 593 {
 594         _enter("%p,%p", local, skb);
 595
 596         skb_queue_tail(&local->event_queue, skb);
 597         rxrpc_queue_local(local);
 598 }
 599
 600 /*
 601  * Extract the wire header from a packet and translate the byte order.
 602  */
 603 static noinline
 604 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 605 {
 606         struct rxrpc_wire_header whdr;
 607
 608         /* dig out the RxRPC connection details */
 609         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 610                 return -EBADMSG;
 611         if (!pskb_pull(skb, sizeof(whdr)))
 612                 BUG();
 613
 614         memset(sp, 0, sizeof(*sp));
 615         sp->hdr.epoch           = ntohl(whdr.epoch);
 616         sp->hdr.cid             = ntohl(whdr.cid);
 617         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 618         sp->hdr.seq             = ntohl(whdr.seq);
 619         sp->hdr.serial          = ntohl(whdr.serial);
 620         sp->hdr.flags           = whdr.flags;
 621         sp->hdr.type            = whdr.type;
 622         sp->hdr.userStatus      = whdr.userStatus;
 623         sp->hdr.securityIndex   = whdr.securityIndex;
 624         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 625         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 626         return 0;
 627 }
 628
 629 /*
 630  * handle data received on the local endpoint
 631  * - may be called in interrupt context
 632  *
 633  * The socket is locked by the caller and this prevents the socket from being
 634  * shut down and the local endpoint from going away, thus sk_user_data will not
 635  * be cleared until this function returns.
 636  */
 637 void rxrpc_data_ready(struct sock *sk)
 638 {
 639         struct rxrpc_connection *conn;
 640         struct rxrpc_skb_priv *sp;
 641         struct rxrpc_local *local = sk->sk_user_data;
 642         struct sk_buff *skb;
 643         int ret, skew;
 644
 645         _enter("%p", sk);
 646
 647         ASSERT(!irqs_disabled());
 648
 649         skb = skb_recv_datagram(sk, 0, 1, &ret);
 650         if (!skb) {
 651                 if (ret == -EAGAIN)
 652                         return;
 653                 _debug("UDP socket error %d", ret);
 654                 return;
 655         }
 656
 657         rxrpc_new_skb(skb);
 658
 659         _net("recv skb %p", skb);
 660
 661         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 662         if (skb_checksum_complete(skb)) {
 663                 rxrpc_free_skb(skb);
 664                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
 665                 _leave(" [CSUM failed]");
 666                 return;
 667         }
 668
 669         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
 670
 671         /* The socket buffer we have is owned by UDP, with UDP's data all over
 672          * it, but we really want our own data there.
 673          */
 674         skb_orphan(skb);
 675         sp = rxrpc_skb(skb);
 676
 677         _net("Rx UDP packet from %08x:%04hu",
 678              ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 679
 680         /* dig out the RxRPC connection details */
 681         if (rxrpc_extract_header(sp, skb) < 0)
 682                 goto bad_message;
 683
 684         _net("Rx RxRPC %s ep=%x call=%x:%x",
 685              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 686              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 687
 688         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 689             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 690                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 691                 goto bad_message;
 692         }
 693
 694         if (sp->hdr.type == RXRPC_PACKET_TYPE_VERSION) {
 695                 rxrpc_post_packet_to_local(local, skb);
 696                 goto out;
 697         }
 698
 699         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 700             (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 701                 goto bad_message;
 702
 703         rcu_read_lock();
 704
 705         conn = rxrpc_find_connection_rcu(local, skb);
 706         if (!conn) {
 707                 skb->priority = 0;
 708                 goto cant_route_call;
 709         }
 710
 711         /* Note the serial number skew here */
 712         skew = (int)sp->hdr.serial - (int)conn->hi_serial;
 713         if (skew >= 0) {
 714                 if (skew > 0)
 715                         conn->hi_serial = sp->hdr.serial;
 716                 skb->priority = 0;
 717         } else {
 718                 skew = -skew;
 719                 skb->priority = min(skew, 65535);
 720         }
 721
 722         if (sp->hdr.callNumber == 0) {
 723                 /* Connection-level packet */
 724                 _debug("CONN %p {%d}", conn, conn->debug_id);
 725                 rxrpc_post_packet_to_conn(conn, skb);
 726                 goto out_unlock;
 727         } else {
 728                 /* Call-bound packets are routed by connection channel. */
 729                 unsigned int channel = sp->hdr.cid & RXRPC_CHANNELMASK;
 730                 struct rxrpc_channel *chan = &conn->channels[channel];
 731                 struct rxrpc_call *call;
 732
 733                 /* Ignore really old calls */
 734                 if (sp->hdr.callNumber < chan->last_call)
 735                         goto discard_unlock;
 736
 737                 if (sp->hdr.callNumber == chan->last_call) {
 738                         /* For the previous service call, if completed
 739                          * successfully, we discard all further packets.
 740                          */
 741                         if (rxrpc_conn_is_service(conn) &&
 742                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
 743                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
 744                                 goto discard_unlock;
 745
 746                         /* But otherwise we need to retransmit the final packet
 747                          * from data cached in the connection record.
 748                          */
 749                         rxrpc_post_packet_to_conn(conn, skb);
 750                         goto out_unlock;
 751                 }
 752
 753                 call = rcu_dereference(chan->call);
 754                 if (!call || atomic_read(&call->usage) == 0)
 755                         goto cant_route_call;
 756
 757                 rxrpc_see_call(call);
 758                 rxrpc_post_packet_to_call(conn, call, skb);
 759                 goto out_unlock;
 760         }
 761
 762 discard_unlock:
 763         rxrpc_free_skb(skb);
 764 out_unlock:
 765         rcu_read_unlock();
 766 out:
 767         return;
 768
 769 cant_route_call:
 770         rcu_read_unlock();
 771
 772         _debug("can't route call");
 773         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 774             sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 775                 if (sp->hdr.seq == 1) {
 776                         _debug("first packet");
 777                         skb_queue_tail(&local->accept_queue, skb);
 778                         rxrpc_queue_work(&local->processor);
 779                         _leave(" [incoming]");
 780                         return;
 781                 }
 782                 skb->priority = RX_INVALID_OPERATION;
 783         } else {
 784                 skb->priority = RX_CALL_DEAD;
 785         }
 786
 787         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 788                 _debug("reject type %d",sp->hdr.type);
 789                 rxrpc_reject_packet(local, skb);
 790         } else {
 791                 rxrpc_free_skb(skb);
 792         }
 793         _leave(" [no call]");
 794         return;
 795
 796 bad_message:
 797         skb->priority = RX_PROTOCOL_ERROR;
 798         rxrpc_reject_packet(local, skb);
 799         _leave(" [badmsg]");
 800 }