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_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_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_RESEND_TIMER, &call->events);
 295                         clear_bit(RXRPC_CALL_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 _abort_code;
 314         u32 serial, hi_serial, seq, 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         serial = ntohl(sp->hdr.serial);
 334         hi_serial = atomic_read(&call->conn->hi_serial);
 335         while (serial > hi_serial)
 336                 hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
 337                                            serial);
 338
 339         /* request ACK generation for any ACK or DATA packet that requests
 340          * it */
 341         if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 342                 _proto("ACK Requested on %%%u", serial);
 343                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial, false);
 344         }
 345
 346         switch (sp->hdr.type) {
 347         case RXRPC_PACKET_TYPE_ABORT:
 348                 _debug("abort");
 349
 350                 if (skb_copy_bits(skb, 0, &_abort_code,
 351                                   sizeof(_abort_code)) < 0)
 352                         goto protocol_error;
 353
 354                 abort_code = ntohl(_abort_code);
 355                 _proto("Rx ABORT %%%u { %x }", serial, abort_code);
 356
 357                 write_lock_bh(&call->state_lock);
 358                 if (call->state < RXRPC_CALL_COMPLETE) {
 359                         call->state = RXRPC_CALL_REMOTELY_ABORTED;
 360                         call->abort_code = abort_code;
 361                         set_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
 362                         rxrpc_queue_call(call);
 363                 }
 364                 goto free_packet_unlock;
 365
 366         case RXRPC_PACKET_TYPE_BUSY:
 367                 _proto("Rx BUSY %%%u", serial);
 368
 369                 if (call->conn->out_clientflag)
 370                         goto protocol_error;
 371
 372                 write_lock_bh(&call->state_lock);
 373                 switch (call->state) {
 374                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 375                         call->state = RXRPC_CALL_SERVER_BUSY;
 376                         set_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
 377                         rxrpc_queue_call(call);
 378                 case RXRPC_CALL_SERVER_BUSY:
 379                         goto free_packet_unlock;
 380                 default:
 381                         goto protocol_error_locked;
 382                 }
 383
 384         default:
 385                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], serial);
 386                 goto protocol_error;
 387
 388         case RXRPC_PACKET_TYPE_DATA:
 389                 seq = ntohl(sp->hdr.seq);
 390
 391                 _proto("Rx DATA %%%u { #%u }", serial, seq);
 392
 393                 if (seq == 0)
 394                         goto protocol_error;
 395
 396                 call->ackr_prev_seq = sp->hdr.seq;
 397
 398                 /* received data implicitly ACKs all of the request packets we
 399                  * sent when we're acting as a client */
 400                 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 401                         rxrpc_assume_implicit_ackall(call, serial);
 402
 403                 switch (rxrpc_fast_process_data(call, skb, seq)) {
 404                 case 0:
 405                         skb = NULL;
 406                         goto done;
 407
 408                 default:
 409                         BUG();
 410
 411                         /* data packet received beyond the last packet */
 412                 case -EBADMSG:
 413                         goto protocol_error;
 414                 }
 415
 416         case RXRPC_PACKET_TYPE_ACKALL:
 417         case RXRPC_PACKET_TYPE_ACK:
 418                 /* ACK processing is done in process context */
 419                 read_lock_bh(&call->state_lock);
 420                 if (call->state < RXRPC_CALL_DEAD) {
 421                         skb_queue_tail(&call->rx_queue, skb);
 422                         rxrpc_queue_call(call);
 423                         skb = NULL;
 424                 }
 425                 read_unlock_bh(&call->state_lock);
 426                 goto free_packet;
 427         }
 428
 429 protocol_error:
 430         _debug("protocol error");
 431         write_lock_bh(&call->state_lock);
 432 protocol_error_locked:
 433         if (call->state <= RXRPC_CALL_COMPLETE) {
 434                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 435                 call->abort_code = RX_PROTOCOL_ERROR;
 436                 set_bit(RXRPC_CALL_ABORT, &call->events);
 437                 rxrpc_queue_call(call);
 438         }
 439 free_packet_unlock:
 440         write_unlock_bh(&call->state_lock);
 441 free_packet:
 442         rxrpc_free_skb(skb);
 443 done:
 444         _leave("");
 445 }
 446
 447 /*
 448  * split up a jumbo data packet
 449  */
 450 static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
 451                                        struct sk_buff *jumbo)
 452 {
 453         struct rxrpc_jumbo_header jhdr;
 454         struct rxrpc_skb_priv *sp;
 455         struct sk_buff *part;
 456
 457         _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
 458
 459         sp = rxrpc_skb(jumbo);
 460
 461         do {
 462                 sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
 463
 464                 /* make a clone to represent the first subpacket in what's left
 465                  * of the jumbo packet */
 466                 part = skb_clone(jumbo, GFP_ATOMIC);
 467                 if (!part) {
 468                         /* simply ditch the tail in the event of ENOMEM */
 469                         pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
 470                         break;
 471                 }
 472                 rxrpc_new_skb(part);
 473
 474                 pskb_trim(part, RXRPC_JUMBO_DATALEN);
 475
 476                 if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
 477                         goto protocol_error;
 478
 479                 if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
 480                         goto protocol_error;
 481                 if (!pskb_pull(jumbo, sizeof(jhdr)))
 482                         BUG();
 483
 484                 sp->hdr.seq     = htonl(ntohl(sp->hdr.seq) + 1);
 485                 sp->hdr.serial  = htonl(ntohl(sp->hdr.serial) + 1);
 486                 sp->hdr.flags   = jhdr.flags;
 487                 sp->hdr._rsvd   = jhdr._rsvd;
 488
 489                 _proto("Rx DATA Jumbo %%%u", ntohl(sp->hdr.serial) - 1);
 490
 491                 rxrpc_fast_process_packet(call, part);
 492                 part = NULL;
 493
 494         } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
 495
 496         rxrpc_fast_process_packet(call, jumbo);
 497         _leave("");
 498         return;
 499
 500 protocol_error:
 501         _debug("protocol error");
 502         rxrpc_free_skb(part);
 503         rxrpc_free_skb(jumbo);
 504         write_lock_bh(&call->state_lock);
 505         if (call->state <= RXRPC_CALL_COMPLETE) {
 506                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 507                 call->abort_code = RX_PROTOCOL_ERROR;
 508                 set_bit(RXRPC_CALL_ABORT, &call->events);
 509                 rxrpc_queue_call(call);
 510         }
 511         write_unlock_bh(&call->state_lock);
 512         _leave("");
 513 }
 514
 515 /*
 516  * post an incoming packet to the appropriate call/socket to deal with
 517  * - must get rid of the sk_buff, either by freeing it or by queuing it
 518  */
 519 static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 520                                       struct sk_buff *skb)
 521 {
 522         struct rxrpc_skb_priv *sp;
 523
 524         _enter("%p,%p", call, skb);
 525
 526         sp = rxrpc_skb(skb);
 527
 528         _debug("extant call [%d]", call->state);
 529
 530         read_lock(&call->state_lock);
 531         switch (call->state) {
 532         case RXRPC_CALL_LOCALLY_ABORTED:
 533                 if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events)) {
 534                         rxrpc_queue_call(call);
 535                         goto free_unlock;
 536                 }
 537         case RXRPC_CALL_REMOTELY_ABORTED:
 538         case RXRPC_CALL_NETWORK_ERROR:
 539         case RXRPC_CALL_DEAD:
 540                 goto dead_call;
 541         case RXRPC_CALL_COMPLETE:
 542         case RXRPC_CALL_CLIENT_FINAL_ACK:
 543                 /* complete server call */
 544                 if (call->conn->in_clientflag)
 545                         goto dead_call;
 546                 /* resend last packet of a completed call */
 547                 _debug("final ack again");
 548                 rxrpc_get_call(call);
 549                 set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
 550                 rxrpc_queue_call(call);
 551                 goto free_unlock;
 552         default:
 553                 break;
 554         }
 555
 556         read_unlock(&call->state_lock);
 557         rxrpc_get_call(call);
 558
 559         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 560             sp->hdr.flags & RXRPC_JUMBO_PACKET)
 561                 rxrpc_process_jumbo_packet(call, skb);
 562         else
 563                 rxrpc_fast_process_packet(call, skb);
 564
 565         rxrpc_put_call(call);
 566         goto done;
 567
 568 dead_call:
 569         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 570                 skb->priority = RX_CALL_DEAD;
 571                 rxrpc_reject_packet(call->conn->trans->local, skb);
 572                 goto unlock;
 573         }
 574 free_unlock:
 575         rxrpc_free_skb(skb);
 576 unlock:
 577         read_unlock(&call->state_lock);
 578 done:
 579         _leave("");
 580 }
 581
 582 /*
 583  * post connection-level events to the connection
 584  * - this includes challenges, responses and some aborts
 585  */
 586 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 587                                       struct sk_buff *skb)
 588 {
 589         _enter("%p,%p", conn, skb);
 590
 591         atomic_inc(&conn->usage);
 592         skb_queue_tail(&conn->rx_queue, skb);
 593         rxrpc_queue_conn(conn);
 594 }
 595
 596 /*
 597  * post endpoint-level events to the local endpoint
 598  * - this includes debug and version messages
 599  */
 600 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 601                                        struct sk_buff *skb)
 602 {
 603         _enter("%p,%p", local, skb);
 604
 605         atomic_inc(&local->usage);
 606         skb_queue_tail(&local->event_queue, skb);
 607         rxrpc_queue_work(&local->event_processor);
 608 }
 609
 610 static struct rxrpc_connection *rxrpc_conn_from_local(struct rxrpc_local *local,
 611                                                struct sk_buff *skb,
 612                                                struct rxrpc_skb_priv *sp)
 613 {
 614         struct rxrpc_peer *peer;
 615         struct rxrpc_transport *trans;
 616         struct rxrpc_connection *conn;
 617
 618         peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr,
 619                                 udp_hdr(skb)->source);
 620         if (IS_ERR(peer))
 621                 goto cant_find_conn;
 622
 623         trans = rxrpc_find_transport(local, peer);
 624         rxrpc_put_peer(peer);
 625         if (!trans)
 626                 goto cant_find_conn;
 627
 628         conn = rxrpc_find_connection(trans, &sp->hdr);
 629         rxrpc_put_transport(trans);
 630         if (!conn)
 631                 goto cant_find_conn;
 632
 633         return conn;
 634 cant_find_conn:
 635         return NULL;
 636 }
 637
 638 /*
 639  * handle data received on the local endpoint
 640  * - may be called in interrupt context
 641  */
 642 void rxrpc_data_ready(struct sock *sk)
 643 {
 644         struct rxrpc_skb_priv *sp;
 645         struct rxrpc_local *local;
 646         struct sk_buff *skb;
 647         int ret;
 648
 649         _enter("%p", sk);
 650
 651         ASSERT(!irqs_disabled());
 652
 653         read_lock_bh(&rxrpc_local_lock);
 654         local = sk->sk_user_data;
 655         if (local && atomic_read(&local->usage) > 0)
 656                 rxrpc_get_local(local);
 657         else
 658                 local = NULL;
 659         read_unlock_bh(&rxrpc_local_lock);
 660         if (!local) {
 661                 _leave(" [local dead]");
 662                 return;
 663         }
 664
 665         skb = skb_recv_datagram(sk, 0, 1, &ret);
 666         if (!skb) {
 667                 rxrpc_put_local(local);
 668                 if (ret == -EAGAIN)
 669                         return;
 670                 _debug("UDP socket error %d", ret);
 671                 return;
 672         }
 673
 674         rxrpc_new_skb(skb);
 675
 676         _net("recv skb %p", skb);
 677
 678         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 679         if (skb_checksum_complete(skb)) {
 680                 rxrpc_free_skb(skb);
 681                 rxrpc_put_local(local);
 682                 UDP_INC_STATS_BH(&init_net, UDP_MIB_INERRORS, 0);
 683                 _leave(" [CSUM failed]");
 684                 return;
 685         }
 686
 687         UDP_INC_STATS_BH(&init_net, UDP_MIB_INDATAGRAMS, 0);
 688
 689         /* the socket buffer we have is owned by UDP, with UDP's data all over
 690          * it, but we really want our own */
 691         skb_orphan(skb);
 692         sp = rxrpc_skb(skb);
 693         memset(sp, 0, sizeof(*sp));
 694
 695         _net("Rx UDP packet from %08x:%04hu",
 696              ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 697
 698         /* dig out the RxRPC connection details */
 699         if (skb_copy_bits(skb, sizeof(struct udphdr), &sp->hdr,
 700                           sizeof(sp->hdr)) < 0)
 701                 goto bad_message;
 702         if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(sp->hdr)))
 703                 BUG();
 704
 705         _net("Rx RxRPC %s ep=%x call=%x:%x",
 706              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 707              ntohl(sp->hdr.epoch),
 708              ntohl(sp->hdr.cid),
 709              ntohl(sp->hdr.callNumber));
 710
 711         if (sp->hdr.type == 0 || sp->hdr.type >= RXRPC_N_PACKET_TYPES) {
 712                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 713                 goto bad_message;
 714         }
 715
 716         if (sp->hdr.type == RXRPC_PACKET_TYPE_VERSION) {
 717                 rxrpc_post_packet_to_local(local, skb);
 718                 goto out;
 719         }
 720
 721         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 722             (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 723                 goto bad_message;
 724
 725         if (sp->hdr.callNumber == 0) {
 726                 /* This is a connection-level packet. These should be
 727                  * fairly rare, so the extra overhead of looking them up the
 728                  * old-fashioned way doesn't really hurt */
 729                 struct rxrpc_connection *conn;
 730
 731                 conn = rxrpc_conn_from_local(local, skb, sp);
 732                 if (!conn)
 733                         goto cant_route_call;
 734
 735                 _debug("CONN %p {%d}", conn, conn->debug_id);
 736                 rxrpc_post_packet_to_conn(conn, skb);
 737                 rxrpc_put_connection(conn);
 738         } else {
 739                 struct rxrpc_call *call;
 740                 u8 in_clientflag = 0;
 741
 742                 if (sp->hdr.flags & RXRPC_CLIENT_INITIATED)
 743                         in_clientflag = RXRPC_CLIENT_INITIATED;
 744                 call = rxrpc_find_call_hash(in_clientflag, sp->hdr.cid,
 745                                             sp->hdr.callNumber, sp->hdr.epoch,
 746                                             sp->hdr.serviceId, local, AF_INET,
 747                                             (u8 *)&ip_hdr(skb)->saddr);
 748                 if (call)
 749                         rxrpc_post_packet_to_call(call, skb);
 750                 else
 751                         goto cant_route_call;
 752         }
 753
 754 out:
 755         rxrpc_put_local(local);
 756         return;
 757
 758 cant_route_call:
 759         _debug("can't route call");
 760         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 761             sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 762                 if (sp->hdr.seq == cpu_to_be32(1)) {
 763                         _debug("first packet");
 764                         skb_queue_tail(&local->accept_queue, skb);
 765                         rxrpc_queue_work(&local->acceptor);
 766                         rxrpc_put_local(local);
 767                         _leave(" [incoming]");
 768                         return;
 769                 }
 770                 skb->priority = RX_INVALID_OPERATION;
 771         } else {
 772                 skb->priority = RX_CALL_DEAD;
 773         }
 774
 775         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 776                 _debug("reject type %d",sp->hdr.type);
 777                 rxrpc_reject_packet(local, skb);
 778         }
 779         rxrpc_put_local(local);
 780         _leave(" [no call]");
 781         return;
 782
 783 bad_message:
 784         skb->priority = RX_PROTOCOL_ERROR;
 785         rxrpc_reject_packet(local, skb);
 786         rxrpc_put_local(local);
 787         _leave(" [badmsg]");
 788 }