git.oblomov.eu Git - linux-2.6/blob - 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 <net/sock.h>
  21 #include <net/af_rxrpc.h>
  22 #include <net/ip.h>
  23 #include <net/udp.h>
  24 #include <net/net_namespace.h>
  25 #include "ar-internal.h"
  26
  27 unsigned long rxrpc_ack_timeout = 1;
  28
  29 const char *rxrpc_pkts[] = {
  30         "?00",
  31         "DATA", "ACK", "BUSY", "ABORT", "ACKALL", "CHALL", "RESP", "DEBUG",
  32         "?09", "?10", "?11", "?12", "?13", "?14", "?15"
  33 };
  34
  35 /*
  36  * queue a packet for recvmsg to pass to userspace
  37  * - the caller must hold a lock on call->lock
  38  * - must not be called with interrupts disabled (sk_filter() disables BH's)
  39  * - eats the packet whether successful or not
  40  * - there must be just one reference to the packet, which the caller passes to
  41  *   this function
  42  */
  43 int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
  44                         bool force, bool terminal)
  45 {
  46         struct rxrpc_skb_priv *sp;
  47         struct rxrpc_sock *rx = call->socket;
  48         struct sock *sk;
  49         int skb_len, ret;
  50
  51         _enter(",,%d,%d", force, terminal);
  52
  53         ASSERT(!irqs_disabled());
  54
  55         sp = rxrpc_skb(skb);
  56         ASSERTCMP(sp->call, ==, call);
  57
  58         /* if we've already posted the terminal message for a call, then we
  59          * don't post any more */
  60         if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
  61                 _debug("already terminated");
  62                 ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
  63                 skb->destructor = NULL;
  64                 sp->call = NULL;
  65                 rxrpc_put_call(call);
  66                 rxrpc_free_skb(skb);
  67                 return 0;
  68         }
  69
  70         sk = &rx->sk;
  71
  72         if (!force) {
  73                 /* cast skb->rcvbuf to unsigned...  It's pointless, but
  74                  * reduces number of warnings when compiling with -W
  75                  * --ANK */
  76 //              ret = -ENOBUFS;
  77 //              if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
  78 //                  (unsigned) sk->sk_rcvbuf)
  79 //                      goto out;
  80
  81                 ret = sk_filter(sk, skb);
  82                 if (ret < 0)
  83                         goto out;
  84         }
  85
  86         spin_lock_bh(&sk->sk_receive_queue.lock);
  87         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
  88             !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
  89             call->socket->sk.sk_state != RXRPC_CLOSE) {
  90                 skb->destructor = rxrpc_packet_destructor;
  91                 skb->dev = NULL;
  92                 skb->sk = sk;
  93                 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
  94
  95                 if (terminal) {
  96                         _debug("<<<< TERMINAL MESSAGE >>>>");
  97                         set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
  98                 }
  99
 100                 /* allow interception by a kernel service */
 101                 if (rx->interceptor) {
 102                         rx->interceptor(sk, call->user_call_ID, skb);
 103                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 104                 } else {
 105
 106                         /* Cache the SKB length before we tack it onto the
 107                          * receive queue.  Once it is added it no longer
 108                          * belongs to us and may be freed by other threads of
 109                          * control pulling packets from the queue */
 110                         skb_len = skb->len;
 111
 112                         _net("post skb %p", skb);
 113                         __skb_queue_tail(&sk->sk_receive_queue, skb);
 114                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 115
 116                         if (!sock_flag(sk, SOCK_DEAD))
 117                                 sk->sk_data_ready(sk, skb_len);
 118                 }
 119                 skb = NULL;
 120         } else {
 121                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 122         }
 123         ret = 0;
 124
 125 out:
 126         /* release the socket buffer */
 127         if (skb) {
 128                 skb->destructor = NULL;
 129                 sp->call = NULL;
 130                 rxrpc_put_call(call);
 131                 rxrpc_free_skb(skb);
 132         }
 133
 134         _leave(" = %d", ret);
 135         return ret;
 136 }
 137
 138 /*
 139  * process a DATA packet, posting the packet to the appropriate queue
 140  * - eats the packet if successful
 141  */
 142 static int rxrpc_fast_process_data(struct rxrpc_call *call,
 143                                    struct sk_buff *skb, u32 seq)
 144 {
 145         struct rxrpc_skb_priv *sp;
 146         bool terminal;
 147         int ret, ackbit, ack;
 148
 149         _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
 150
 151         sp = rxrpc_skb(skb);
 152         ASSERTCMP(sp->call, ==, NULL);
 153
 154         spin_lock(&call->lock);
 155
 156         if (call->state > RXRPC_CALL_COMPLETE)
 157                 goto discard;
 158
 159         ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
 160         ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
 161         ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
 162
 163         if (seq < call->rx_data_post) {
 164                 _debug("dup #%u [-%u]", seq, call->rx_data_post);
 165                 ack = RXRPC_ACK_DUPLICATE;
 166                 ret = -ENOBUFS;
 167                 goto discard_and_ack;
 168         }
 169
 170         /* we may already have the packet in the out of sequence queue */
 171         ackbit = seq - (call->rx_data_eaten + 1);
 172         ASSERTCMP(ackbit, >=, 0);
 173         if (__test_and_set_bit(ackbit, call->ackr_window)) {
 174                 _debug("dup oos #%u [%u,%u]",
 175                        seq, call->rx_data_eaten, call->rx_data_post);
 176                 ack = RXRPC_ACK_DUPLICATE;
 177                 goto discard_and_ack;
 178         }
 179
 180         if (seq >= call->ackr_win_top) {
 181                 _debug("exceed #%u [%u]", seq, call->ackr_win_top);
 182                 __clear_bit(ackbit, call->ackr_window);
 183                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 184                 goto discard_and_ack;
 185         }
 186
 187         if (seq == call->rx_data_expect) {
 188                 clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
 189                 call->rx_data_expect++;
 190         } else if (seq > call->rx_data_expect) {
 191                 _debug("oos #%u [%u]", seq, call->rx_data_expect);
 192                 call->rx_data_expect = seq + 1;
 193                 if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
 194                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 195                         goto enqueue_and_ack;
 196                 }
 197                 goto enqueue_packet;
 198         }
 199
 200         if (seq != call->rx_data_post) {
 201                 _debug("ahead #%u [%u]", seq, call->rx_data_post);
 202                 goto enqueue_packet;
 203         }
 204
 205         if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
 206                 goto protocol_error;
 207
 208         /* if the packet need security things doing to it, then it goes down
 209          * the slow path */
 210         if (call->conn->security)
 211                 goto enqueue_packet;
 212
 213         sp->call = call;
 214         rxrpc_get_call(call);
 215         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 216                     !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 217         ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
 218         if (ret < 0) {
 219                 if (ret == -ENOMEM || ret == -ENOBUFS) {
 220                         __clear_bit(ackbit, call->ackr_window);
 221                         ack = RXRPC_ACK_NOSPACE;
 222                         goto discard_and_ack;
 223                 }
 224                 goto out;
 225         }
 226
 227         skb = NULL;
 228
 229         _debug("post #%u", seq);
 230         ASSERTCMP(call->rx_data_post, ==, seq);
 231         call->rx_data_post++;
 232
 233         if (sp->hdr.flags & RXRPC_LAST_PACKET)
 234                 set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);
 235
 236         /* if we've reached an out of sequence packet then we need to drain
 237          * that queue into the socket Rx queue now */
 238         if (call->rx_data_post == call->rx_first_oos) {
 239                 _debug("drain rx oos now");
 240                 read_lock(&call->state_lock);
 241                 if (call->state < RXRPC_CALL_COMPLETE &&
 242                     !test_and_set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events))
 243                         rxrpc_queue_call(call);
 244                 read_unlock(&call->state_lock);
 245         }
 246
 247         spin_unlock(&call->lock);
 248         atomic_inc(&call->ackr_not_idle);
 249         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, sp->hdr.serial, false);
 250         _leave(" = 0 [posted]");
 251         return 0;
 252
 253 protocol_error:
 254         ret = -EBADMSG;
 255 out:
 256         spin_unlock(&call->lock);
 257         _leave(" = %d", ret);
 258         return ret;
 259
 260 discard_and_ack:
 261         _debug("discard and ACK packet %p", skb);
 262         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
 263 discard:
 264         spin_unlock(&call->lock);
 265         rxrpc_free_skb(skb);
 266         _leave(" = 0 [discarded]");
 267         return 0;
 268
 269 enqueue_and_ack:
 270         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
 271 enqueue_packet:
 272         _net("defer skb %p", skb);
 273         spin_unlock(&call->lock);
 274         skb_queue_tail(&call->rx_queue, skb);
 275         atomic_inc(&call->ackr_not_idle);
 276         read_lock(&call->state_lock);
 277         if (call->state < RXRPC_CALL_DEAD)
 278                 rxrpc_queue_call(call);
 279         read_unlock(&call->state_lock);
 280         _leave(" = 0 [queued]");
 281         return 0;
 282 }
 283
 284 /*
 285  * assume an implicit ACKALL of the transmission phase of a client socket upon
 286  * reception of the first reply packet
 287  */
 288 static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
 289 {
 290         write_lock_bh(&call->state_lock);
 291
 292         switch (call->state) {
 293         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 294                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 295                 call->acks_latest = serial;
 296
 297                 _debug("implicit ACKALL %%%u", call->acks_latest);
 298                 set_bit(RXRPC_CALL_RCVD_ACKALL, &call->events);
 299                 write_unlock_bh(&call->state_lock);
 300
 301                 if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
 302                         clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 303                         clear_bit(RXRPC_CALL_RESEND, &call->events);
 304                         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 305                 }
 306                 break;
 307
 308         default:
 309                 write_unlock_bh(&call->state_lock);
 310                 break;
 311         }
 312 }
 313
 314 /*
 315  * post an incoming packet to the nominated call to deal with
 316  * - must get rid of the sk_buff, either by freeing it or by queuing it
 317  */
 318 void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
 319 {
 320         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 321         __be32 _abort_code;
 322         u32 serial, hi_serial, seq, abort_code;
 323
 324         _enter("%p,%p", call, skb);
 325
 326         ASSERT(!irqs_disabled());
 327
 328 #if 0 // INJECT RX ERROR
 329         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 330                 static int skip = 0;
 331                 if (++skip == 3) {
 332                         printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
 333                         skip = 0;
 334                         goto free_packet;
 335                 }
 336         }
 337 #endif
 338
 339         /* track the latest serial number on this connection for ACK packet
 340          * information */
 341         serial = ntohl(sp->hdr.serial);
 342         hi_serial = atomic_read(&call->conn->hi_serial);
 343         while (serial > hi_serial)
 344                 hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
 345                                            serial);
 346
 347         /* request ACK generation for any ACK or DATA packet that requests
 348          * it */
 349         if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 350                 _proto("ACK Requested on %%%u", serial);
 351                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial,
 352                                   !(sp->hdr.flags & RXRPC_MORE_PACKETS));
 353         }
 354
 355         switch (sp->hdr.type) {
 356         case RXRPC_PACKET_TYPE_ABORT:
 357                 _debug("abort");
 358
 359                 if (skb_copy_bits(skb, 0, &_abort_code,
 360                                   sizeof(_abort_code)) < 0)
 361                         goto protocol_error;
 362
 363                 abort_code = ntohl(_abort_code);
 364                 _proto("Rx ABORT %%%u { %x }", serial, abort_code);
 365
 366                 write_lock_bh(&call->state_lock);
 367                 if (call->state < RXRPC_CALL_COMPLETE) {
 368                         call->state = RXRPC_CALL_REMOTELY_ABORTED;
 369                         call->abort_code = abort_code;
 370                         set_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
 371                         rxrpc_queue_call(call);
 372                 }
 373                 goto free_packet_unlock;
 374
 375         case RXRPC_PACKET_TYPE_BUSY:
 376                 _proto("Rx BUSY %%%u", serial);
 377
 378                 if (call->conn->out_clientflag)
 379                         goto protocol_error;
 380
 381                 write_lock_bh(&call->state_lock);
 382                 switch (call->state) {
 383                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 384                         call->state = RXRPC_CALL_SERVER_BUSY;
 385                         set_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
 386                         rxrpc_queue_call(call);
 387                 case RXRPC_CALL_SERVER_BUSY:
 388                         goto free_packet_unlock;
 389                 default:
 390                         goto protocol_error_locked;
 391                 }
 392
 393         default:
 394                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], serial);
 395                 goto protocol_error;
 396
 397         case RXRPC_PACKET_TYPE_DATA:
 398                 seq = ntohl(sp->hdr.seq);
 399
 400                 _proto("Rx DATA %%%u { #%u }", serial, seq);
 401
 402                 if (seq == 0)
 403                         goto protocol_error;
 404
 405                 call->ackr_prev_seq = sp->hdr.seq;
 406
 407                 /* received data implicitly ACKs all of the request packets we
 408                  * sent when we're acting as a client */
 409                 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 410                         rxrpc_assume_implicit_ackall(call, serial);
 411
 412                 switch (rxrpc_fast_process_data(call, skb, seq)) {
 413                 case 0:
 414                         skb = NULL;
 415                         goto done;
 416
 417                 default:
 418                         BUG();
 419
 420                         /* data packet received beyond the last packet */
 421                 case -EBADMSG:
 422                         goto protocol_error;
 423                 }
 424
 425         case RXRPC_PACKET_TYPE_ACK:
 426                 /* ACK processing is done in process context */
 427                 read_lock_bh(&call->state_lock);
 428                 if (call->state < RXRPC_CALL_DEAD) {
 429                         skb_queue_tail(&call->rx_queue, skb);
 430                         rxrpc_queue_call(call);
 431                         skb = NULL;
 432                 }
 433                 read_unlock_bh(&call->state_lock);
 434                 goto free_packet;
 435         }
 436
 437 protocol_error:
 438         _debug("protocol error");
 439         write_lock_bh(&call->state_lock);
 440 protocol_error_locked:
 441         if (call->state <= RXRPC_CALL_COMPLETE) {
 442                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 443                 call->abort_code = RX_PROTOCOL_ERROR;
 444                 set_bit(RXRPC_CALL_ABORT, &call->events);
 445                 rxrpc_queue_call(call);
 446         }
 447 free_packet_unlock:
 448         write_unlock_bh(&call->state_lock);
 449 free_packet:
 450         rxrpc_free_skb(skb);
 451 done:
 452         _leave("");
 453 }
 454
 455 /*
 456  * split up a jumbo data packet
 457  */
 458 static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
 459                                        struct sk_buff *jumbo)
 460 {
 461         struct rxrpc_jumbo_header jhdr;
 462         struct rxrpc_skb_priv *sp;
 463         struct sk_buff *part;
 464
 465         _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
 466
 467         sp = rxrpc_skb(jumbo);
 468
 469         do {
 470                 sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
 471
 472                 /* make a clone to represent the first subpacket in what's left
 473                  * of the jumbo packet */
 474                 part = skb_clone(jumbo, GFP_ATOMIC);
 475                 if (!part) {
 476                         /* simply ditch the tail in the event of ENOMEM */
 477                         pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
 478                         break;
 479                 }
 480                 rxrpc_new_skb(part);
 481
 482                 pskb_trim(part, RXRPC_JUMBO_DATALEN);
 483
 484                 if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
 485                         goto protocol_error;
 486
 487                 if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
 488                         goto protocol_error;
 489                 if (!pskb_pull(jumbo, sizeof(jhdr)))
 490                         BUG();
 491
 492                 sp->hdr.seq     = htonl(ntohl(sp->hdr.seq) + 1);
 493                 sp->hdr.serial  = htonl(ntohl(sp->hdr.serial) + 1);
 494                 sp->hdr.flags   = jhdr.flags;
 495                 sp->hdr._rsvd   = jhdr._rsvd;
 496
 497                 _proto("Rx DATA Jumbo %%%u", ntohl(sp->hdr.serial) - 1);
 498
 499                 rxrpc_fast_process_packet(call, part);
 500                 part = NULL;
 501
 502         } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
 503
 504         rxrpc_fast_process_packet(call, jumbo);
 505         _leave("");
 506         return;
 507
 508 protocol_error:
 509         _debug("protocol error");
 510         rxrpc_free_skb(part);
 511         rxrpc_free_skb(jumbo);
 512         write_lock_bh(&call->state_lock);
 513         if (call->state <= RXRPC_CALL_COMPLETE) {
 514                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 515                 call->abort_code = RX_PROTOCOL_ERROR;
 516                 set_bit(RXRPC_CALL_ABORT, &call->events);
 517                 rxrpc_queue_call(call);
 518         }
 519         write_unlock_bh(&call->state_lock);
 520         _leave("");
 521 }
 522
 523 /*
 524  * post an incoming packet to the appropriate call/socket to deal with
 525  * - must get rid of the sk_buff, either by freeing it or by queuing it
 526  */
 527 static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
 528                                       struct sk_buff *skb)
 529 {
 530         struct rxrpc_skb_priv *sp;
 531         struct rxrpc_call *call;
 532         struct rb_node *p;
 533         __be32 call_id;
 534
 535         _enter("%p,%p", conn, skb);
 536
 537         read_lock_bh(&conn->lock);
 538
 539         sp = rxrpc_skb(skb);
 540
 541         /* look at extant calls by channel number first */
 542         call = conn->channels[ntohl(sp->hdr.cid) & RXRPC_CHANNELMASK];
 543         if (!call || call->call_id != sp->hdr.callNumber)
 544                 goto call_not_extant;
 545
 546         _debug("extant call [%d]", call->state);
 547         ASSERTCMP(call->conn, ==, conn);
 548
 549         read_lock(&call->state_lock);
 550         switch (call->state) {
 551         case RXRPC_CALL_LOCALLY_ABORTED:
 552                 if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
 553                         rxrpc_queue_call(call);
 554         case RXRPC_CALL_REMOTELY_ABORTED:
 555         case RXRPC_CALL_NETWORK_ERROR:
 556         case RXRPC_CALL_DEAD:
 557                 goto free_unlock;
 558         default:
 559                 break;
 560         }
 561
 562         read_unlock(&call->state_lock);
 563         rxrpc_get_call(call);
 564         read_unlock_bh(&conn->lock);
 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 call_not_extant:
 576         /* search the completed calls in case what we're dealing with is
 577          * there */
 578         _debug("call not extant");
 579
 580         call_id = sp->hdr.callNumber;
 581         p = conn->calls.rb_node;
 582         while (p) {
 583                 call = rb_entry(p, struct rxrpc_call, conn_node);
 584
 585                 if (call_id < call->call_id)
 586                         p = p->rb_left;
 587                 else if (call_id > call->call_id)
 588                         p = p->rb_right;
 589                 else
 590                         goto found_completed_call;
 591         }
 592
 593 dead_call:
 594         /* it's a either a really old call that we no longer remember or its a
 595          * new incoming call */
 596         read_unlock_bh(&conn->lock);
 597
 598         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 599             sp->hdr.seq == cpu_to_be32(1)) {
 600                 _debug("incoming call");
 601                 skb_queue_tail(&conn->trans->local->accept_queue, skb);
 602                 rxrpc_queue_work(&conn->trans->local->acceptor);
 603                 goto done;
 604         }
 605
 606         _debug("dead call");
 607         skb->priority = RX_CALL_DEAD;
 608         rxrpc_reject_packet(conn->trans->local, skb);
 609         goto done;
 610
 611         /* resend last packet of a completed call
 612          * - client calls may have been aborted or ACK'd
 613          * - server calls may have been aborted
 614          */
 615 found_completed_call:
 616         _debug("completed call");
 617
 618         if (atomic_read(&call->usage) == 0)
 619                 goto dead_call;
 620
 621         /* synchronise any state changes */
 622         read_lock(&call->state_lock);
 623         ASSERTIFCMP(call->state != RXRPC_CALL_CLIENT_FINAL_ACK,
 624                     call->state, >=, RXRPC_CALL_COMPLETE);
 625
 626         if (call->state == RXRPC_CALL_LOCALLY_ABORTED ||
 627             call->state == RXRPC_CALL_REMOTELY_ABORTED ||
 628             call->state == RXRPC_CALL_DEAD) {
 629                 read_unlock(&call->state_lock);
 630                 goto dead_call;
 631         }
 632
 633         if (call->conn->in_clientflag) {
 634                 read_unlock(&call->state_lock);
 635                 goto dead_call; /* complete server call */
 636         }
 637
 638         _debug("final ack again");
 639         rxrpc_get_call(call);
 640         set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
 641         rxrpc_queue_call(call);
 642
 643 free_unlock:
 644         read_unlock(&call->state_lock);
 645         read_unlock_bh(&conn->lock);
 646         rxrpc_free_skb(skb);
 647 done:
 648         _leave("");
 649 }
 650
 651 /*
 652  * post connection-level events to the connection
 653  * - this includes challenges, responses and some aborts
 654  */
 655 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 656                                       struct sk_buff *skb)
 657 {
 658         _enter("%p,%p", conn, skb);
 659
 660         atomic_inc(&conn->usage);
 661         skb_queue_tail(&conn->rx_queue, skb);
 662         rxrpc_queue_conn(conn);
 663 }
 664
 665 /*
 666  * handle data received on the local endpoint
 667  * - may be called in interrupt context
 668  */
 669 void rxrpc_data_ready(struct sock *sk, int count)
 670 {
 671         struct rxrpc_connection *conn;
 672         struct rxrpc_transport *trans;
 673         struct rxrpc_skb_priv *sp;
 674         struct rxrpc_local *local;
 675         struct rxrpc_peer *peer;
 676         struct sk_buff *skb;
 677         int ret;
 678
 679         _enter("%p, %d", sk, count);
 680
 681         ASSERT(!irqs_disabled());
 682
 683         read_lock_bh(&rxrpc_local_lock);
 684         local = sk->sk_user_data;
 685         if (local && atomic_read(&local->usage) > 0)
 686                 rxrpc_get_local(local);
 687         else
 688                 local = NULL;
 689         read_unlock_bh(&rxrpc_local_lock);
 690         if (!local) {
 691                 _leave(" [local dead]");
 692                 return;
 693         }
 694
 695         skb = skb_recv_datagram(sk, 0, 1, &ret);
 696         if (!skb) {
 697                 rxrpc_put_local(local);
 698                 if (ret == -EAGAIN)
 699                         return;
 700                 _debug("UDP socket error %d", ret);
 701                 return;
 702         }
 703
 704         rxrpc_new_skb(skb);
 705
 706         _net("recv skb %p", skb);
 707
 708         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 709         if (skb_checksum_complete(skb)) {
 710                 rxrpc_free_skb(skb);
 711                 rxrpc_put_local(local);
 712                 UDP_INC_STATS_BH(&init_net, UDP_MIB_INERRORS, 0);
 713                 _leave(" [CSUM failed]");
 714                 return;
 715         }
 716
 717         UDP_INC_STATS_BH(&init_net, UDP_MIB_INDATAGRAMS, 0);
 718
 719         /* the socket buffer we have is owned by UDP, with UDP's data all over
 720          * it, but we really want our own */
 721         skb_orphan(skb);
 722         sp = rxrpc_skb(skb);
 723         memset(sp, 0, sizeof(*sp));
 724
 725         _net("Rx UDP packet from %08x:%04hu",
 726              ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 727
 728         /* dig out the RxRPC connection details */
 729         if (skb_copy_bits(skb, sizeof(struct udphdr), &sp->hdr,
 730                           sizeof(sp->hdr)) < 0)
 731                 goto bad_message;
 732         if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(sp->hdr)))
 733                 BUG();
 734
 735         _net("Rx RxRPC %s ep=%x call=%x:%x",
 736              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 737              ntohl(sp->hdr.epoch),
 738              ntohl(sp->hdr.cid),
 739              ntohl(sp->hdr.callNumber));
 740
 741         if (sp->hdr.type == 0 || sp->hdr.type >= RXRPC_N_PACKET_TYPES) {
 742                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 743                 goto bad_message;
 744         }
 745
 746         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 747             (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 748                 goto bad_message;
 749
 750         peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr, udp_hdr(skb)->source);
 751         if (IS_ERR(peer))
 752                 goto cant_route_call;
 753
 754         trans = rxrpc_find_transport(local, peer);
 755         rxrpc_put_peer(peer);
 756         if (!trans)
 757                 goto cant_route_call;
 758
 759         conn = rxrpc_find_connection(trans, &sp->hdr);
 760         rxrpc_put_transport(trans);
 761         if (!conn)
 762                 goto cant_route_call;
 763
 764         _debug("CONN %p {%d}", conn, conn->debug_id);
 765
 766         if (sp->hdr.callNumber == 0)
 767                 rxrpc_post_packet_to_conn(conn, skb);
 768         else
 769                 rxrpc_post_packet_to_call(conn, skb);
 770         rxrpc_put_connection(conn);
 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 == cpu_to_be32(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         _debug("reject");
 792         rxrpc_reject_packet(local, skb);
 793         rxrpc_put_local(local);
 794         _leave(" [no call]");
 795         return;
 796
 797 bad_message:
 798         skb->priority = RX_PROTOCOL_ERROR;
 799         rxrpc_reject_packet(local, skb);
 800         rxrpc_put_local(local);
 801         _leave(" [badmsg]");
 802 }