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", "?13", "?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 skb_len, 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
 105                         /* Cache the SKB length before we tack it onto the
 106                          * receive queue.  Once it is added it no longer
 107                          * belongs to us and may be freed by other threads of
 108                          * control pulling packets from the queue */
 109                         skb_len = skb->len;
 110
 111                         _net("post skb %p", skb);
 112                         __skb_queue_tail(&sk->sk_receive_queue, skb);
 113                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 114
 115                         if (!sock_flag(sk, SOCK_DEAD))
 116                                 sk->sk_data_ready(sk);
 117                 }
 118                 skb = NULL;
 119         } else {
 120                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 121         }
 122         ret = 0;
 123
 124 out:
 125         /* release the socket buffer */
 126         if (skb) {
 127                 skb->destructor = NULL;
 128                 sp->call = NULL;
 129                 rxrpc_put_call(call);
 130                 rxrpc_free_skb(skb);
 131         }
 132
 133         _leave(" = %d", ret);
 134         return ret;
 135 }
 136
 137 /*
 138  * process a DATA packet, posting the packet to the appropriate queue
 139  * - eats the packet if successful
 140  */
 141 static int rxrpc_fast_process_data(struct rxrpc_call *call,
 142                                    struct sk_buff *skb, u32 seq)
 143 {
 144         struct rxrpc_skb_priv *sp;
 145         bool terminal;
 146         int ret, ackbit, ack;
 147
 148         _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
 149
 150         sp = rxrpc_skb(skb);
 151         ASSERTCMP(sp->call, ==, NULL);
 152
 153         spin_lock(&call->lock);
 154
 155         if (call->state > RXRPC_CALL_COMPLETE)
 156                 goto discard;
 157
 158         ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
 159         ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
 160         ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
 161
 162         if (seq < call->rx_data_post) {
 163                 _debug("dup #%u [-%u]", seq, call->rx_data_post);
 164                 ack = RXRPC_ACK_DUPLICATE;
 165                 ret = -ENOBUFS;
 166                 goto discard_and_ack;
 167         }
 168
 169         /* we may already have the packet in the out of sequence queue */
 170         ackbit = seq - (call->rx_data_eaten + 1);
 171         ASSERTCMP(ackbit, >=, 0);
 172         if (__test_and_set_bit(ackbit, call->ackr_window)) {
 173                 _debug("dup oos #%u [%u,%u]",
 174                        seq, call->rx_data_eaten, call->rx_data_post);
 175                 ack = RXRPC_ACK_DUPLICATE;
 176                 goto discard_and_ack;
 177         }
 178
 179         if (seq >= call->ackr_win_top) {
 180                 _debug("exceed #%u [%u]", seq, call->ackr_win_top);
 181                 __clear_bit(ackbit, call->ackr_window);
 182                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 183                 goto discard_and_ack;
 184         }
 185
 186         if (seq == call->rx_data_expect) {
 187                 clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
 188                 call->rx_data_expect++;
 189         } else if (seq > call->rx_data_expect) {
 190                 _debug("oos #%u [%u]", seq, call->rx_data_expect);
 191                 call->rx_data_expect = seq + 1;
 192                 if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
 193                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 194                         goto enqueue_and_ack;
 195                 }
 196                 goto enqueue_packet;
 197         }
 198
 199         if (seq != call->rx_data_post) {
 200                 _debug("ahead #%u [%u]", seq, call->rx_data_post);
 201                 goto enqueue_packet;
 202         }
 203
 204         if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
 205                 goto protocol_error;
 206
 207         /* if the packet need security things doing to it, then it goes down
 208          * the slow path */
 209         if (call->conn->security)
 210                 goto enqueue_packet;
 211
 212         sp->call = call;
 213         rxrpc_get_call(call);
 214         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 215                     !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 216         ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
 217         if (ret < 0) {
 218                 if (ret == -ENOMEM || ret == -ENOBUFS) {
 219                         __clear_bit(ackbit, call->ackr_window);
 220                         ack = RXRPC_ACK_NOSPACE;
 221                         goto discard_and_ack;
 222                 }
 223                 goto out;
 224         }
 225
 226         skb = NULL;
 227
 228         _debug("post #%u", seq);
 229         ASSERTCMP(call->rx_data_post, ==, seq);
 230         call->rx_data_post++;
 231
 232         if (sp->hdr.flags & RXRPC_LAST_PACKET)
 233                 set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);
 234
 235         /* if we've reached an out of sequence packet then we need to drain
 236          * that queue into the socket Rx queue now */
 237         if (call->rx_data_post == call->rx_first_oos) {
 238                 _debug("drain rx oos now");
 239                 read_lock(&call->state_lock);
 240                 if (call->state < RXRPC_CALL_COMPLETE &&
 241                     !test_and_set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events))
 242                         rxrpc_queue_call(call);
 243                 read_unlock(&call->state_lock);
 244         }
 245
 246         spin_unlock(&call->lock);
 247         atomic_inc(&call->ackr_not_idle);
 248         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, sp->hdr.serial, false);
 249         _leave(" = 0 [posted]");
 250         return 0;
 251
 252 protocol_error:
 253         ret = -EBADMSG;
 254 out:
 255         spin_unlock(&call->lock);
 256         _leave(" = %d", ret);
 257         return ret;
 258
 259 discard_and_ack:
 260         _debug("discard and ACK packet %p", skb);
 261         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
 262 discard:
 263         spin_unlock(&call->lock);
 264         rxrpc_free_skb(skb);
 265         _leave(" = 0 [discarded]");
 266         return 0;
 267
 268 enqueue_and_ack:
 269         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
 270 enqueue_packet:
 271         _net("defer skb %p", skb);
 272         spin_unlock(&call->lock);
 273         skb_queue_tail(&call->rx_queue, skb);
 274         atomic_inc(&call->ackr_not_idle);
 275         read_lock(&call->state_lock);
 276         if (call->state < RXRPC_CALL_DEAD)
 277                 rxrpc_queue_call(call);
 278         read_unlock(&call->state_lock);
 279         _leave(" = 0 [queued]");
 280         return 0;
 281 }
 282
 283 /*
 284  * assume an implicit ACKALL of the transmission phase of a client socket upon
 285  * reception of the first reply packet
 286  */
 287 static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
 288 {
 289         write_lock_bh(&call->state_lock);
 290
 291         switch (call->state) {
 292         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 293                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 294                 call->acks_latest = serial;
 295
 296                 _debug("implicit ACKALL %%%u", call->acks_latest);
 297                 set_bit(RXRPC_CALL_RCVD_ACKALL, &call->events);
 298                 write_unlock_bh(&call->state_lock);
 299
 300                 if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
 301                         clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 302                         clear_bit(RXRPC_CALL_RESEND, &call->events);
 303                         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 304                 }
 305                 break;
 306
 307         default:
 308                 write_unlock_bh(&call->state_lock);
 309                 break;
 310         }
 311 }
 312
 313 /*
 314  * post an incoming packet to the nominated call to deal with
 315  * - must get rid of the sk_buff, either by freeing it or by queuing it
 316  */
 317 void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
 318 {
 319         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 320         __be32 _abort_code;
 321         u32 serial, hi_serial, seq, abort_code;
 322
 323         _enter("%p,%p", call, skb);
 324
 325         ASSERT(!irqs_disabled());
 326
 327 #if 0 // INJECT RX ERROR
 328         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 329                 static int skip = 0;
 330                 if (++skip == 3) {
 331                         printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
 332                         skip = 0;
 333                         goto free_packet;
 334                 }
 335         }
 336 #endif
 337
 338         /* track the latest serial number on this connection for ACK packet
 339          * information */
 340         serial = ntohl(sp->hdr.serial);
 341         hi_serial = atomic_read(&call->conn->hi_serial);
 342         while (serial > hi_serial)
 343                 hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
 344                                            serial);
 345
 346         /* request ACK generation for any ACK or DATA packet that requests
 347          * it */
 348         if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 349                 _proto("ACK Requested on %%%u", serial);
 350                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial, false);
 351         }
 352
 353         switch (sp->hdr.type) {
 354         case RXRPC_PACKET_TYPE_ABORT:
 355                 _debug("abort");
 356
 357                 if (skb_copy_bits(skb, 0, &_abort_code,
 358                                   sizeof(_abort_code)) < 0)
 359                         goto protocol_error;
 360
 361                 abort_code = ntohl(_abort_code);
 362                 _proto("Rx ABORT %%%u { %x }", serial, abort_code);
 363
 364                 write_lock_bh(&call->state_lock);
 365                 if (call->state < RXRPC_CALL_COMPLETE) {
 366                         call->state = RXRPC_CALL_REMOTELY_ABORTED;
 367                         call->abort_code = abort_code;
 368                         set_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
 369                         rxrpc_queue_call(call);
 370                 }
 371                 goto free_packet_unlock;
 372
 373         case RXRPC_PACKET_TYPE_BUSY:
 374                 _proto("Rx BUSY %%%u", serial);
 375
 376                 if (call->conn->out_clientflag)
 377                         goto protocol_error;
 378
 379                 write_lock_bh(&call->state_lock);
 380                 switch (call->state) {
 381                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 382                         call->state = RXRPC_CALL_SERVER_BUSY;
 383                         set_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
 384                         rxrpc_queue_call(call);
 385                 case RXRPC_CALL_SERVER_BUSY:
 386                         goto free_packet_unlock;
 387                 default:
 388                         goto protocol_error_locked;
 389                 }
 390
 391         default:
 392                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], serial);
 393                 goto protocol_error;
 394
 395         case RXRPC_PACKET_TYPE_DATA:
 396                 seq = ntohl(sp->hdr.seq);
 397
 398                 _proto("Rx DATA %%%u { #%u }", serial, seq);
 399
 400                 if (seq == 0)
 401                         goto protocol_error;
 402
 403                 call->ackr_prev_seq = sp->hdr.seq;
 404
 405                 /* received data implicitly ACKs all of the request packets we
 406                  * sent when we're acting as a client */
 407                 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 408                         rxrpc_assume_implicit_ackall(call, serial);
 409
 410                 switch (rxrpc_fast_process_data(call, skb, seq)) {
 411                 case 0:
 412                         skb = NULL;
 413                         goto done;
 414
 415                 default:
 416                         BUG();
 417
 418                         /* data packet received beyond the last packet */
 419                 case -EBADMSG:
 420                         goto protocol_error;
 421                 }
 422
 423         case RXRPC_PACKET_TYPE_ACKALL:
 424         case RXRPC_PACKET_TYPE_ACK:
 425                 /* ACK processing is done in process context */
 426                 read_lock_bh(&call->state_lock);
 427                 if (call->state < RXRPC_CALL_DEAD) {
 428                         skb_queue_tail(&call->rx_queue, skb);
 429                         rxrpc_queue_call(call);
 430                         skb = NULL;
 431                 }
 432                 read_unlock_bh(&call->state_lock);
 433                 goto free_packet;
 434         }
 435
 436 protocol_error:
 437         _debug("protocol error");
 438         write_lock_bh(&call->state_lock);
 439 protocol_error_locked:
 440         if (call->state <= RXRPC_CALL_COMPLETE) {
 441                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 442                 call->abort_code = RX_PROTOCOL_ERROR;
 443                 set_bit(RXRPC_CALL_ABORT, &call->events);
 444                 rxrpc_queue_call(call);
 445         }
 446 free_packet_unlock:
 447         write_unlock_bh(&call->state_lock);
 448 free_packet:
 449         rxrpc_free_skb(skb);
 450 done:
 451         _leave("");
 452 }
 453
 454 /*
 455  * split up a jumbo data packet
 456  */
 457 static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
 458                                        struct sk_buff *jumbo)
 459 {
 460         struct rxrpc_jumbo_header jhdr;
 461         struct rxrpc_skb_priv *sp;
 462         struct sk_buff *part;
 463
 464         _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
 465
 466         sp = rxrpc_skb(jumbo);
 467
 468         do {
 469                 sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
 470
 471                 /* make a clone to represent the first subpacket in what's left
 472                  * of the jumbo packet */
 473                 part = skb_clone(jumbo, GFP_ATOMIC);
 474                 if (!part) {
 475                         /* simply ditch the tail in the event of ENOMEM */
 476                         pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
 477                         break;
 478                 }
 479                 rxrpc_new_skb(part);
 480
 481                 pskb_trim(part, RXRPC_JUMBO_DATALEN);
 482
 483                 if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
 484                         goto protocol_error;
 485
 486                 if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
 487                         goto protocol_error;
 488                 if (!pskb_pull(jumbo, sizeof(jhdr)))
 489                         BUG();
 490
 491                 sp->hdr.seq     = htonl(ntohl(sp->hdr.seq) + 1);
 492                 sp->hdr.serial  = htonl(ntohl(sp->hdr.serial) + 1);
 493                 sp->hdr.flags   = jhdr.flags;
 494                 sp->hdr._rsvd   = jhdr._rsvd;
 495
 496                 _proto("Rx DATA Jumbo %%%u", ntohl(sp->hdr.serial) - 1);
 497
 498                 rxrpc_fast_process_packet(call, part);
 499                 part = NULL;
 500
 501         } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
 502
 503         rxrpc_fast_process_packet(call, jumbo);
 504         _leave("");
 505         return;
 506
 507 protocol_error:
 508         _debug("protocol error");
 509         rxrpc_free_skb(part);
 510         rxrpc_free_skb(jumbo);
 511         write_lock_bh(&call->state_lock);
 512         if (call->state <= RXRPC_CALL_COMPLETE) {
 513                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 514                 call->abort_code = RX_PROTOCOL_ERROR;
 515                 set_bit(RXRPC_CALL_ABORT, &call->events);
 516                 rxrpc_queue_call(call);
 517         }
 518         write_unlock_bh(&call->state_lock);
 519         _leave("");
 520 }
 521
 522 /*
 523  * post an incoming packet to the appropriate call/socket to deal with
 524  * - must get rid of the sk_buff, either by freeing it or by queuing it
 525  */
 526 static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 527                                       struct sk_buff *skb)
 528 {
 529         struct rxrpc_skb_priv *sp;
 530
 531         _enter("%p,%p", call, skb);
 532
 533         sp = rxrpc_skb(skb);
 534
 535         _debug("extant call [%d]", call->state);
 536
 537         read_lock(&call->state_lock);
 538         switch (call->state) {
 539         case RXRPC_CALL_LOCALLY_ABORTED:
 540                 if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events)) {
 541                         rxrpc_queue_call(call);
 542                         goto free_unlock;
 543                 }
 544         case RXRPC_CALL_REMOTELY_ABORTED:
 545         case RXRPC_CALL_NETWORK_ERROR:
 546         case RXRPC_CALL_DEAD:
 547                 goto dead_call;
 548         case RXRPC_CALL_COMPLETE:
 549         case RXRPC_CALL_CLIENT_FINAL_ACK:
 550                 /* complete server call */
 551                 if (call->conn->in_clientflag)
 552                         goto dead_call;
 553                 /* resend last packet of a completed call */
 554                 _debug("final ack again");
 555                 rxrpc_get_call(call);
 556                 set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
 557                 rxrpc_queue_call(call);
 558                 goto free_unlock;
 559         default:
 560                 break;
 561         }
 562
 563         read_unlock(&call->state_lock);
 564         rxrpc_get_call(call);
 565
 566         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 567             sp->hdr.flags & RXRPC_JUMBO_PACKET)
 568                 rxrpc_process_jumbo_packet(call, skb);
 569         else
 570                 rxrpc_fast_process_packet(call, skb);
 571
 572         rxrpc_put_call(call);
 573         goto done;
 574
 575 dead_call:
 576         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 577                 skb->priority = RX_CALL_DEAD;
 578                 rxrpc_reject_packet(call->conn->trans->local, skb);
 579                 goto unlock;
 580         }
 581 free_unlock:
 582         rxrpc_free_skb(skb);
 583 unlock:
 584         read_unlock(&call->state_lock);
 585 done:
 586         _leave("");
 587 }
 588
 589 /*
 590  * post connection-level events to the connection
 591  * - this includes challenges, responses and some aborts
 592  */
 593 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 594                                       struct sk_buff *skb)
 595 {
 596         _enter("%p,%p", conn, skb);
 597
 598         atomic_inc(&conn->usage);
 599         skb_queue_tail(&conn->rx_queue, skb);
 600         rxrpc_queue_conn(conn);
 601 }
 602
 603 static struct rxrpc_connection *rxrpc_conn_from_local(struct rxrpc_local *local,
 604                                                struct sk_buff *skb,
 605                                                struct rxrpc_skb_priv *sp)
 606 {
 607         struct rxrpc_peer *peer;
 608         struct rxrpc_transport *trans;
 609         struct rxrpc_connection *conn;
 610
 611         peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr,
 612                                 udp_hdr(skb)->source);
 613         if (IS_ERR(peer))
 614                 goto cant_find_conn;
 615
 616         trans = rxrpc_find_transport(local, peer);
 617         rxrpc_put_peer(peer);
 618         if (!trans)
 619                 goto cant_find_conn;
 620
 621         conn = rxrpc_find_connection(trans, &sp->hdr);
 622         rxrpc_put_transport(trans);
 623         if (!conn)
 624                 goto cant_find_conn;
 625
 626         return conn;
 627 cant_find_conn:
 628         return NULL;
 629 }
 630
 631 /*
 632  * handle data received on the local endpoint
 633  * - may be called in interrupt context
 634  */
 635 void rxrpc_data_ready(struct sock *sk)
 636 {
 637         struct rxrpc_skb_priv *sp;
 638         struct rxrpc_local *local;
 639         struct sk_buff *skb;
 640         int ret;
 641
 642         _enter("%p", sk);
 643
 644         ASSERT(!irqs_disabled());
 645
 646         read_lock_bh(&rxrpc_local_lock);
 647         local = sk->sk_user_data;
 648         if (local && atomic_read(&local->usage) > 0)
 649                 rxrpc_get_local(local);
 650         else
 651                 local = NULL;
 652         read_unlock_bh(&rxrpc_local_lock);
 653         if (!local) {
 654                 _leave(" [local dead]");
 655                 return;
 656         }
 657
 658         skb = skb_recv_datagram(sk, 0, 1, &ret);
 659         if (!skb) {
 660                 rxrpc_put_local(local);
 661                 if (ret == -EAGAIN)
 662                         return;
 663                 _debug("UDP socket error %d", ret);
 664                 return;
 665         }
 666
 667         rxrpc_new_skb(skb);
 668
 669         _net("recv skb %p", skb);
 670
 671         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 672         if (skb_checksum_complete(skb)) {
 673                 rxrpc_free_skb(skb);
 674                 rxrpc_put_local(local);
 675                 UDP_INC_STATS_BH(&init_net, UDP_MIB_INERRORS, 0);
 676                 _leave(" [CSUM failed]");
 677                 return;
 678         }
 679
 680         UDP_INC_STATS_BH(&init_net, UDP_MIB_INDATAGRAMS, 0);
 681
 682         /* the socket buffer we have is owned by UDP, with UDP's data all over
 683          * it, but we really want our own */
 684         skb_orphan(skb);
 685         sp = rxrpc_skb(skb);
 686         memset(sp, 0, sizeof(*sp));
 687
 688         _net("Rx UDP packet from %08x:%04hu",
 689              ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 690
 691         /* dig out the RxRPC connection details */
 692         if (skb_copy_bits(skb, sizeof(struct udphdr), &sp->hdr,
 693                           sizeof(sp->hdr)) < 0)
 694                 goto bad_message;
 695         if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(sp->hdr)))
 696                 BUG();
 697
 698         _net("Rx RxRPC %s ep=%x call=%x:%x",
 699              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 700              ntohl(sp->hdr.epoch),
 701              ntohl(sp->hdr.cid),
 702              ntohl(sp->hdr.callNumber));
 703
 704         if (sp->hdr.type == 0 || sp->hdr.type >= RXRPC_N_PACKET_TYPES) {
 705                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 706                 goto bad_message;
 707         }
 708
 709         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 710             (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 711                 goto bad_message;
 712
 713         if (sp->hdr.callNumber == 0) {
 714                 /* This is a connection-level packet. These should be
 715                  * fairly rare, so the extra overhead of looking them up the
 716                  * old-fashioned way doesn't really hurt */
 717                 struct rxrpc_connection *conn;
 718
 719                 conn = rxrpc_conn_from_local(local, skb, sp);
 720                 if (!conn)
 721                         goto cant_route_call;
 722
 723                 _debug("CONN %p {%d}", conn, conn->debug_id);
 724                 rxrpc_post_packet_to_conn(conn, skb);
 725                 rxrpc_put_connection(conn);
 726         } else {
 727                 struct rxrpc_call *call;
 728                 u8 in_clientflag = 0;
 729
 730                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
 731                         in_clientflag = RXRPC_CLIENT_INITIATED;
 732                 call = rxrpc_find_call_hash(in_clientflag, sp->hdr.cid,
 733                                             sp->hdr.callNumber, sp->hdr.epoch,
 734                                             sp->hdr.serviceId, local, AF_INET,
 735                                             (u8 *)&ip_hdr(skb)->saddr);
 736                 if (call)
 737                         rxrpc_post_packet_to_call(call, skb);
 738                 else
 739                         goto cant_route_call;
 740         }
 741         rxrpc_put_local(local);
 742         return;
 743
 744 cant_route_call:
 745         _debug("can't route call");
 746         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 747             sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 748                 if (sp->hdr.seq == cpu_to_be32(1)) {
 749                         _debug("first packet");
 750                         skb_queue_tail(&local->accept_queue, skb);
 751                         rxrpc_queue_work(&local->acceptor);
 752                         rxrpc_put_local(local);
 753                         _leave(" [incoming]");
 754                         return;
 755                 }
 756                 skb->priority = RX_INVALID_OPERATION;
 757         } else {
 758                 skb->priority = RX_CALL_DEAD;
 759         }
 760
 761         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 762                 _debug("reject type %d",sp->hdr.type);
 763                 rxrpc_reject_packet(local, skb);
 764         }
 765         rxrpc_put_local(local);
 766         _leave(" [no call]");
 767         return;
 768
 769 bad_message:
 770         skb->priority = RX_PROTOCOL_ERROR;
 771         rxrpc_reject_packet(local, skb);
 772         rxrpc_put_local(local);
 773         _leave(" [badmsg]");
 774 }