net/rxrpc/input.c

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