net/rxrpc/ar-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 #include <linux/module.h>
  13 #include <linux/net.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/errqueue.h>
  16 #include <linux/udp.h>
  17 #include <linux/in.h>
  18 #include <linux/in6.h>
  19 #include <linux/icmp.h>
  20 #include <linux/gfp.h>
  21 #include <net/sock.h>
  22 #include <net/af_rxrpc.h>
  23 #include <net/ip.h>
  24 #include <net/udp.h>
  25 #include <net/net_namespace.h>
  26 #include "ar-internal.h"
  27
  28 const char *rxrpc_pkts[] = {
  29         "?00",
  30         "DATA", "ACK", "BUSY", "ABORT", "ACKALL", "CHALL", "RESP", "DEBUG",
  31         "?09", "?10", "?11", "?12", "VERSION", "?14", "?15"
  32 };
  33
  34 /*
  35  * queue a packet for recvmsg to pass to userspace
  36  * - the caller must hold a lock on call->lock
  37  * - must not be called with interrupts disabled (sk_filter() disables BH's)
  38  * - eats the packet whether successful or not
  39  * - there must be just one reference to the packet, which the caller passes to
  40  *   this function
  41  */
  42 int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
  43                         bool force, bool terminal)
  44 {
  45         struct rxrpc_skb_priv *sp;
  46         struct rxrpc_sock *rx = call->socket;
  47         struct sock *sk;
  48         int ret;
  49
  50         _enter(",,%d,%d", force, terminal);
  51
  52         ASSERT(!irqs_disabled());
  53
  54         sp = rxrpc_skb(skb);
  55         ASSERTCMP(sp->call, ==, call);
  56
  57         /* if we've already posted the terminal message for a call, then we
  58          * don't post any more */
  59         if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
  60                 _debug("already terminated");
  61                 ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
  62                 skb->destructor = NULL;
  63                 sp->call = NULL;
  64                 rxrpc_put_call(call);
  65                 rxrpc_free_skb(skb);
  66                 return 0;
  67         }
  68
  69         sk = &rx->sk;
  70
  71         if (!force) {
  72                 /* cast skb->rcvbuf to unsigned...  It's pointless, but
  73                  * reduces number of warnings when compiling with -W
  74                  * --ANK */
  75 //              ret = -ENOBUFS;
  76 //              if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
  77 //                  (unsigned int) sk->sk_rcvbuf)
  78 //                      goto out;
  79
  80                 ret = sk_filter(sk, skb);
  81                 if (ret < 0)
  82                         goto out;
  83         }
  84
  85         spin_lock_bh(&sk->sk_receive_queue.lock);
  86         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
  87             !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
  88             call->socket->sk.sk_state != RXRPC_CLOSE) {
  89                 skb->destructor = rxrpc_packet_destructor;
  90                 skb->dev = NULL;
  91                 skb->sk = sk;
  92                 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
  93
  94                 if (terminal) {
  95                         _debug("<<<< TERMINAL MESSAGE >>>>");
  96                         set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
  97                 }
  98
  99                 /* allow interception by a kernel service */
 100                 if (rx->interceptor) {
 101                         rx->interceptor(sk, call->user_call_ID, skb);
 102                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 103                 } else {
 104                         _net("post skb %p", skb);
 105                         __skb_queue_tail(&sk->sk_receive_queue, skb);
 106                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 107
 108                         if (!sock_flag(sk, SOCK_DEAD))
 109                                 sk->sk_data_ready(sk);
 110                 }
 111                 skb = NULL;
 112         } else {
 113                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 114         }
 115         ret = 0;
 116
 117 out:
 118         /* release the socket buffer */
 119         if (skb) {
 120                 skb->destructor = NULL;
 121                 sp->call = NULL;
 122                 rxrpc_put_call(call);
 123                 rxrpc_free_skb(skb);
 124         }
 125
 126         _leave(" = %d", ret);
 127         return ret;
 128 }
 129
 130 /*
 131  * process a DATA packet, posting the packet to the appropriate queue
 132  * - eats the packet if successful
 133  */
 134 static int rxrpc_fast_process_data(struct rxrpc_call *call,
 135                                    struct sk_buff *skb, u32 seq)
 136 {
 137         struct rxrpc_skb_priv *sp;
 138         bool terminal;
 139         int ret, ackbit, ack;
 140
 141         _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
 142
 143         sp = rxrpc_skb(skb);
 144         ASSERTCMP(sp->call, ==, NULL);
 145
 146         spin_lock(&call->lock);
 147
 148         if (call->state > RXRPC_CALL_COMPLETE)
 149                 goto discard;
 150
 151         ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
 152         ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
 153         ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
 154
 155         if (seq < call->rx_data_post) {
 156                 _debug("dup #%u [-%u]", seq, call->rx_data_post);
 157                 ack = RXRPC_ACK_DUPLICATE;
 158                 ret = -ENOBUFS;
 159                 goto discard_and_ack;
 160         }
 161
 162         /* we may already have the packet in the out of sequence queue */
 163         ackbit = seq - (call->rx_data_eaten + 1);
 164         ASSERTCMP(ackbit, >=, 0);
 165         if (__test_and_set_bit(ackbit, call->ackr_window)) {
 166                 _debug("dup oos #%u [%u,%u]",
 167                        seq, call->rx_data_eaten, call->rx_data_post);
 168                 ack = RXRPC_ACK_DUPLICATE;
 169                 goto discard_and_ack;
 170         }
 171
 172         if (seq >= call->ackr_win_top) {
 173                 _debug("exceed #%u [%u]", seq, call->ackr_win_top);
 174                 __clear_bit(ackbit, call->ackr_window);
 175                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 176                 goto discard_and_ack;
 177         }
 178
 179         if (seq == call->rx_data_expect) {
 180                 clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
 181                 call->rx_data_expect++;
 182         } else if (seq > call->rx_data_expect) {
 183                 _debug("oos #%u [%u]", seq, call->rx_data_expect);
 184                 call->rx_data_expect = seq + 1;
 185                 if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
 186                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 187                         goto enqueue_and_ack;
 188                 }
 189                 goto enqueue_packet;
 190         }
 191
 192         if (seq != call->rx_data_post) {
 193                 _debug("ahead #%u [%u]", seq, call->rx_data_post);
 194                 goto enqueue_packet;
 195         }
 196
 197         if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
 198                 goto protocol_error;
 199
 200         /* if the packet need security things doing to it, then it goes down
 201          * the slow path */
 202         if (call->conn->security)
 203                 goto enqueue_packet;
 204
 205         sp->call = call;
 206         rxrpc_get_call(call);
 207         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 208                     !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 209         ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
 210         if (ret < 0) {
 211                 if (ret == -ENOMEM || ret == -ENOBUFS) {
 212                         __clear_bit(ackbit, call->ackr_window);
 213                         ack = RXRPC_ACK_NOSPACE;
 214                         goto discard_and_ack;
 215                 }
 216                 goto out;
 217         }
 218
 219         skb = NULL;
 220
 221         _debug("post #%u", seq);
 222         ASSERTCMP(call->rx_data_post, ==, seq);
 223         call->rx_data_post++;
 224
 225         if (sp->hdr.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, sp->hdr.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, sp->hdr.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, sp->hdr.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 hi_serial, 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         /* track the latest serial number on this connection for ACK packet
 332          * information */
 333         hi_serial = atomic_read(&call->conn->hi_serial);
 334         while (sp->hdr.serial > hi_serial)
 335                 hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
 336                                            sp->hdr.serial);
 337
 338         /* request ACK generation for any ACK or DATA packet that requests
 339          * it */
 340         if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 341                 _proto("ACK Requested on %%%u", sp->hdr.serial);
 342                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial, false);
 343         }
 344
 345         switch (sp->hdr.type) {
 346         case RXRPC_PACKET_TYPE_ABORT:
 347                 _debug("abort");
 348
 349                 if (skb_copy_bits(skb, 0, &wtmp, sizeof(wtmp)) < 0)
 350                         goto protocol_error;
 351
 352                 abort_code = ntohl(wtmp);
 353                 _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 354
 355                 write_lock_bh(&call->state_lock);
 356                 if (call->state < RXRPC_CALL_COMPLETE) {
 357                         call->state = RXRPC_CALL_REMOTELY_ABORTED;
 358                         call->abort_code = abort_code;
 359                         set_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
 360                         rxrpc_queue_call(call);
 361                 }
 362                 goto free_packet_unlock;
 363
 364         case RXRPC_PACKET_TYPE_BUSY:
 365                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 366
 367                 if (call->conn->out_clientflag)
 368                         goto protocol_error;
 369
 370                 write_lock_bh(&call->state_lock);
 371                 switch (call->state) {
 372                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 373                         call->state = RXRPC_CALL_SERVER_BUSY;
 374                         set_bit(RXRPC_CALL_EV_RCVD_BUSY, &call->events);
 375                         rxrpc_queue_call(call);
 376                 case RXRPC_CALL_SERVER_BUSY:
 377                         goto free_packet_unlock;
 378                 default:
 379                         goto protocol_error_locked;
 380                 }
 381
 382         default:
 383                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 384                 goto protocol_error;
 385
 386         case RXRPC_PACKET_TYPE_DATA:
 387                 _proto("Rx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
 388
 389                 if (sp->hdr.seq == 0)
 390                         goto protocol_error;
 391
 392                 call->ackr_prev_seq = sp->hdr.seq;
 393
 394                 /* received data implicitly ACKs all of the request packets we
 395                  * sent when we're acting as a client */
 396                 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 397                         rxrpc_assume_implicit_ackall(call, sp->hdr.serial);
 398
 399                 switch (rxrpc_fast_process_data(call, skb, sp->hdr.seq)) {
 400                 case 0:
 401                         skb = NULL;
 402                         goto done;
 403
 404                 default:
 405                         BUG();
 406
 407                         /* data packet received beyond the last packet */
 408                 case -EBADMSG:
 409                         goto protocol_error;
 410                 }
 411
 412         case RXRPC_PACKET_TYPE_ACKALL:
 413         case RXRPC_PACKET_TYPE_ACK:
 414                 /* ACK processing is done in process context */
 415                 read_lock_bh(&call->state_lock);
 416                 if (call->state < RXRPC_CALL_DEAD) {
 417                         skb_queue_tail(&call->rx_queue, skb);
 418                         rxrpc_queue_call(call);
 419                         skb = NULL;
 420                 }
 421                 read_unlock_bh(&call->state_lock);
 422                 goto free_packet;
 423         }
 424
 425 protocol_error:
 426         _debug("protocol error");
 427         write_lock_bh(&call->state_lock);
 428 protocol_error_locked:
 429         if (call->state <= RXRPC_CALL_COMPLETE) {
 430                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 431                 call->abort_code = RX_PROTOCOL_ERROR;
 432                 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
 433                 rxrpc_queue_call(call);
 434         }
 435 free_packet_unlock:
 436         write_unlock_bh(&call->state_lock);
 437 free_packet:
 438         rxrpc_free_skb(skb);
 439 done:
 440         _leave("");
 441 }
 442
 443 /*
 444  * split up a jumbo data packet
 445  */
 446 static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
 447                                        struct sk_buff *jumbo)
 448 {
 449         struct rxrpc_jumbo_header jhdr;
 450         struct rxrpc_skb_priv *sp;
 451         struct sk_buff *part;
 452
 453         _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
 454
 455         sp = rxrpc_skb(jumbo);
 456
 457         do {
 458                 sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
 459
 460                 /* make a clone to represent the first subpacket in what's left
 461                  * of the jumbo packet */
 462                 part = skb_clone(jumbo, GFP_ATOMIC);
 463                 if (!part) {
 464                         /* simply ditch the tail in the event of ENOMEM */
 465                         pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
 466                         break;
 467                 }
 468                 rxrpc_new_skb(part);
 469
 470                 pskb_trim(part, RXRPC_JUMBO_DATALEN);
 471
 472                 if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
 473                         goto protocol_error;
 474
 475                 if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
 476                         goto protocol_error;
 477                 if (!pskb_pull(jumbo, sizeof(jhdr)))
 478                         BUG();
 479
 480                 sp->hdr.seq     += 1;
 481                 sp->hdr.serial  += 1;
 482                 sp->hdr.flags   = jhdr.flags;
 483                 sp->hdr._rsvd   = jhdr._rsvd;
 484
 485                 _proto("Rx DATA Jumbo %%%u", sp->hdr.serial - 1);
 486
 487                 rxrpc_fast_process_packet(call, part);
 488                 part = NULL;
 489
 490         } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
 491
 492         rxrpc_fast_process_packet(call, jumbo);
 493         _leave("");
 494         return;
 495
 496 protocol_error:
 497         _debug("protocol error");
 498         rxrpc_free_skb(part);
 499         rxrpc_free_skb(jumbo);
 500         write_lock_bh(&call->state_lock);
 501         if (call->state <= RXRPC_CALL_COMPLETE) {
 502                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 503                 call->abort_code = RX_PROTOCOL_ERROR;
 504                 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
 505                 rxrpc_queue_call(call);
 506         }
 507         write_unlock_bh(&call->state_lock);
 508         _leave("");
 509 }
 510
 511 /*
 512  * post an incoming packet to the appropriate call/socket to deal with
 513  * - must get rid of the sk_buff, either by freeing it or by queuing it
 514  */
 515 static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 516                                       struct sk_buff *skb)
 517 {
 518         struct rxrpc_skb_priv *sp;
 519
 520         _enter("%p,%p", call, skb);
 521
 522         sp = rxrpc_skb(skb);
 523
 524         _debug("extant call [%d]", call->state);
 525
 526         read_lock(&call->state_lock);
 527         switch (call->state) {
 528         case RXRPC_CALL_LOCALLY_ABORTED:
 529                 if (!test_and_set_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
 530                         rxrpc_queue_call(call);
 531                         goto free_unlock;
 532                 }
 533         case RXRPC_CALL_REMOTELY_ABORTED:
 534         case RXRPC_CALL_NETWORK_ERROR:
 535         case RXRPC_CALL_DEAD:
 536                 goto dead_call;
 537         case RXRPC_CALL_COMPLETE:
 538         case RXRPC_CALL_CLIENT_FINAL_ACK:
 539                 /* complete server call */
 540                 if (call->conn->in_clientflag)
 541                         goto dead_call;
 542                 /* resend last packet of a completed call */
 543                 _debug("final ack again");
 544                 rxrpc_get_call(call);
 545                 set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
 546                 rxrpc_queue_call(call);
 547                 goto free_unlock;
 548         default:
 549                 break;
 550         }
 551
 552         read_unlock(&call->state_lock);
 553         rxrpc_get_call(call);
 554
 555         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 556             sp->hdr.flags & RXRPC_JUMBO_PACKET)
 557                 rxrpc_process_jumbo_packet(call, skb);
 558         else
 559                 rxrpc_fast_process_packet(call, skb);
 560
 561         rxrpc_put_call(call);
 562         goto done;
 563
 564 dead_call:
 565         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 566                 skb->priority = RX_CALL_DEAD;
 567                 rxrpc_reject_packet(call->conn->trans->local, skb);
 568                 goto unlock;
 569         }
 570 free_unlock:
 571         rxrpc_free_skb(skb);
 572 unlock:
 573         read_unlock(&call->state_lock);
 574 done:
 575         _leave("");
 576 }
 577
 578 /*
 579  * post connection-level events to the connection
 580  * - this includes challenges, responses and some aborts
 581  */
 582 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 583                                       struct sk_buff *skb)
 584 {
 585         _enter("%p,%p", conn, skb);
 586
 587         atomic_inc(&conn->usage);
 588         skb_queue_tail(&conn->rx_queue, skb);
 589         rxrpc_queue_conn(conn);
 590 }
 591
 592 /*
 593  * post endpoint-level events to the local endpoint
 594  * - this includes debug and version messages
 595  */
 596 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 597                                        struct sk_buff *skb)
 598 {
 599         _enter("%p,%p", local, skb);
 600
 601         atomic_inc(&local->usage);
 602         skb_queue_tail(&local->event_queue, skb);
 603         rxrpc_queue_work(&local->event_processor);
 604 }
 605
 606 /*
 607  * Extract the wire header from a packet and translate the byte order.
 608  */
 609 static noinline
 610 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 611 {
 612         struct rxrpc_wire_header whdr;
 613
 614         /* dig out the RxRPC connection details */
 615         if (skb_copy_bits(skb, sizeof(struct udphdr), &whdr, sizeof(whdr)) < 0)
 616                 return -EBADMSG;
 617         if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(whdr)))
 618                 BUG();
 619
 620         memset(sp, 0, sizeof(*sp));
 621         sp->hdr.epoch           = ntohl(whdr.epoch);
 622         sp->hdr.cid             = ntohl(whdr.cid);
 623         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 624         sp->hdr.seq             = ntohl(whdr.seq);
 625         sp->hdr.serial          = ntohl(whdr.serial);
 626         sp->hdr.flags           = whdr.flags;
 627         sp->hdr.type            = whdr.type;
 628         sp->hdr.userStatus      = whdr.userStatus;
 629         sp->hdr.securityIndex   = whdr.securityIndex;
 630         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 631         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 632         return 0;
 633 }
 634
 635 static struct rxrpc_connection *rxrpc_conn_from_local(struct rxrpc_local *local,
 636                                                struct sk_buff *skb,
 637                                                struct rxrpc_skb_priv *sp)
 638 {
 639         struct rxrpc_peer *peer;
 640         struct rxrpc_transport *trans;
 641         struct rxrpc_connection *conn;
 642
 643         peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr,
 644                                 udp_hdr(skb)->source);
 645         if (IS_ERR(peer))
 646                 goto cant_find_conn;
 647
 648         trans = rxrpc_find_transport(local, peer);
 649         rxrpc_put_peer(peer);
 650         if (!trans)
 651                 goto cant_find_conn;
 652
 653         conn = rxrpc_find_connection(trans, &sp->hdr);
 654         rxrpc_put_transport(trans);
 655         if (!conn)
 656                 goto cant_find_conn;
 657
 658         return conn;
 659 cant_find_conn:
 660         return NULL;
 661 }
 662
 663 /*
 664  * handle data received on the local endpoint
 665  * - may be called in interrupt context
 666  */
 667 void rxrpc_data_ready(struct sock *sk)
 668 {
 669         struct rxrpc_skb_priv *sp;
 670         struct rxrpc_local *local;
 671         struct sk_buff *skb;
 672         int ret;
 673
 674         _enter("%p", sk);
 675
 676         ASSERT(!irqs_disabled());
 677
 678         read_lock_bh(&rxrpc_local_lock);
 679         local = sk->sk_user_data;
 680         if (local && atomic_read(&local->usage) > 0)
 681                 rxrpc_get_local(local);
 682         else
 683                 local = NULL;
 684         read_unlock_bh(&rxrpc_local_lock);
 685         if (!local) {
 686                 _leave(" [local dead]");
 687                 return;
 688         }
 689
 690         skb = skb_recv_datagram(sk, 0, 1, &ret);
 691         if (!skb) {
 692                 rxrpc_put_local(local);
 693                 if (ret == -EAGAIN)
 694                         return;
 695                 _debug("UDP socket error %d", ret);
 696                 return;
 697         }
 698
 699         rxrpc_new_skb(skb);
 700
 701         _net("recv skb %p", skb);
 702
 703         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 704         if (skb_checksum_complete(skb)) {
 705                 rxrpc_free_skb(skb);
 706                 rxrpc_put_local(local);
 707                 UDP_INC_STATS_BH(&init_net, UDP_MIB_INERRORS, 0);
 708                 _leave(" [CSUM failed]");
 709                 return;
 710         }
 711
 712         UDP_INC_STATS_BH(&init_net, UDP_MIB_INDATAGRAMS, 0);
 713
 714         /* The socket buffer we have is owned by UDP, with UDP's data all over
 715          * it, but we really want our own data there.
 716          */
 717         skb_orphan(skb);
 718         sp = rxrpc_skb(skb);
 719
 720         _net("Rx UDP packet from %08x:%04hu",
 721              ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 722
 723         /* dig out the RxRPC connection details */
 724         if (rxrpc_extract_header(sp, skb) < 0)
 725                 goto bad_message;
 726
 727         _net("Rx RxRPC %s ep=%x call=%x:%x",
 728              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 729              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 730
 731         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 732             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 733                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 734                 goto bad_message;
 735         }
 736
 737         if (sp->hdr.type == RXRPC_PACKET_TYPE_VERSION) {
 738                 rxrpc_post_packet_to_local(local, skb);
 739                 goto out;
 740         }
 741
 742         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 743             (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 744                 goto bad_message;
 745
 746         if (sp->hdr.callNumber == 0) {
 747                 /* This is a connection-level packet. These should be
 748                  * fairly rare, so the extra overhead of looking them up the
 749                  * old-fashioned way doesn't really hurt */
 750                 struct rxrpc_connection *conn;
 751
 752                 conn = rxrpc_conn_from_local(local, skb, sp);
 753                 if (!conn)
 754                         goto cant_route_call;
 755
 756                 _debug("CONN %p {%d}", conn, conn->debug_id);
 757                 rxrpc_post_packet_to_conn(conn, skb);
 758                 rxrpc_put_connection(conn);
 759         } else {
 760                 struct rxrpc_call *call;
 761
 762                 call = rxrpc_find_call_hash(&sp->hdr, local,
 763                                             AF_INET, &ip_hdr(skb)->saddr);
 764                 if (call)
 765                         rxrpc_post_packet_to_call(call, skb);
 766                 else
 767                         goto cant_route_call;
 768         }
 769
 770 out:
 771         rxrpc_put_local(local);
 772         return;
 773
 774 cant_route_call:
 775         _debug("can't route call");
 776         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 777             sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 778                 if (sp->hdr.seq == 1) {
 779                         _debug("first packet");
 780                         skb_queue_tail(&local->accept_queue, skb);
 781                         rxrpc_queue_work(&local->acceptor);
 782                         rxrpc_put_local(local);
 783                         _leave(" [incoming]");
 784                         return;
 785                 }
 786                 skb->priority = RX_INVALID_OPERATION;
 787         } else {
 788                 skb->priority = RX_CALL_DEAD;
 789         }
 790
 791         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 792                 _debug("reject type %d",sp->hdr.type);
 793                 rxrpc_reject_packet(local, skb);
 794         }
 795         rxrpc_put_local(local);
 796         _leave(" [no call]");
 797         return;
 798
 799 bad_message:
 800         skb->priority = RX_PROTOCOL_ERROR;
 801         rxrpc_reject_packet(local, skb);
 802         rxrpc_put_local(local);
 803         _leave(" [badmsg]");
 804 }