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;
  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         /* The socket may go away under us */
  63         ret = 0;
  64         rcu_read_lock();
  65         rx = rcu_dereference(call->socket);
  66         if (!rx)
  67                 goto out;
  68         sk = &rx->sk;
  69         if (sock_flag(sk, SOCK_DEAD))
  70                 goto out;
  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 int) 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             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 (skb->mark == RXRPC_SKB_MARK_NEW_CALL &&
 102                     rx->notify_new_call) {
 103                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 104                         skb_queue_tail(&call->knlrecv_queue, skb);
 105                         rx->notify_new_call(&rx->sk);
 106                 } else if (call->notify_rx) {
 107                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 108                         skb_queue_tail(&call->knlrecv_queue, skb);
 109                         call->notify_rx(&rx->sk, call, call->user_call_ID);
 110                 } else {
 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                         sk->sk_data_ready(sk);
 116                 }
 117                 skb = NULL;
 118         } else {
 119                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 120         }
 121         ret = 0;
 122
 123 out:
 124         rxrpc_free_skb(skb);
 125         rcu_read_unlock();
 126
 127         _leave(" = %d", ret);
 128         return ret;
 129 }
 130
 131 /*
 132  * process a DATA packet, posting the packet to the appropriate queue
 133  * - eats the packet if successful
 134  */
 135 static int rxrpc_fast_process_data(struct rxrpc_call *call,
 136                                    struct sk_buff *skb, u32 seq)
 137 {
 138         struct rxrpc_skb_priv *sp;
 139         bool terminal;
 140         int ret, ackbit, ack;
 141         u32 serial;
 142         u16 skew;
 143         u8 flags;
 144
 145         _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
 146
 147         sp = rxrpc_skb(skb);
 148         ASSERTCMP(sp->call, ==, NULL);
 149         flags = sp->hdr.flags;
 150         serial = sp->hdr.serial;
 151         skew = skb->priority;
 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->security_ix)
 210                 goto enqueue_packet;
 211
 212         sp->call = call;
 213         rxrpc_get_call_for_skb(call, skb);
 214         terminal = ((flags & RXRPC_LAST_PACKET) &&
 215                     !(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         sp = NULL;
 228
 229         _debug("post #%u", seq);
 230         ASSERTCMP(call->rx_data_post, ==, seq);
 231         call->rx_data_post++;
 232
 233         if (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_EV_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, skew, 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, skew, 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, skew, 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_COMPLETE)
 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_EV_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_EV_RESEND_TIMER, &call->events);
 303                         clear_bit(RXRPC_CALL_EV_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 wtmp;
 322         u32 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         /* 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", sp->hdr.serial);
 343                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED,
 344                                   skb->priority, sp->hdr.serial, false);
 345         }
 346
 347         switch (sp->hdr.type) {
 348         case RXRPC_PACKET_TYPE_ABORT:
 349                 _debug("abort");
 350
 351                 if (skb_copy_bits(skb, 0, &wtmp, sizeof(wtmp)) < 0)
 352                         goto protocol_error;
 353
 354                 abort_code = ntohl(wtmp);
 355                 _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 356
 357                 if (__rxrpc_set_call_completion(call,
 358                                                 RXRPC_CALL_REMOTELY_ABORTED,
 359                                                 abort_code, ECONNABORTED)) {
 360                         set_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
 361                         rxrpc_queue_call(call);
 362                 }
 363                 goto free_packet;
 364
 365         case RXRPC_PACKET_TYPE_BUSY:
 366                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 367
 368                 if (rxrpc_is_service_call(call))
 369                         goto protocol_error;
 370
 371                 write_lock_bh(&call->state_lock);
 372                 switch (call->state) {
 373                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 374                         __rxrpc_set_call_completion(call,
 375                                                     RXRPC_CALL_SERVER_BUSY,
 376                                                     0, EBUSY);
 377                         set_bit(RXRPC_CALL_EV_RCVD_BUSY, &call->events);
 378                         rxrpc_queue_call(call);
 379                 case RXRPC_CALL_SERVER_BUSY:
 380                         goto free_packet_unlock;
 381                 default:
 382                         goto protocol_error_locked;
 383                 }
 384
 385         default:
 386                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 387                 goto protocol_error;
 388
 389         case RXRPC_PACKET_TYPE_DATA:
 390                 _proto("Rx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
 391
 392                 if (sp->hdr.seq == 0)
 393                         goto protocol_error;
 394
 395                 call->ackr_prev_seq = sp->hdr.seq;
 396
 397                 /* received data implicitly ACKs all of the request packets we
 398                  * sent when we're acting as a client */
 399                 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 400                         rxrpc_assume_implicit_ackall(call, sp->hdr.serial);
 401
 402                 switch (rxrpc_fast_process_data(call, skb, sp->hdr.seq)) {
 403                 case 0:
 404                         skb = NULL;
 405                         goto done;
 406
 407                 default:
 408                         BUG();
 409
 410                         /* data packet received beyond the last packet */
 411                 case -EBADMSG:
 412                         goto protocol_error;
 413                 }
 414
 415         case RXRPC_PACKET_TYPE_ACKALL:
 416         case RXRPC_PACKET_TYPE_ACK:
 417                 /* ACK processing is done in process context */
 418                 read_lock_bh(&call->state_lock);
 419                 if (call->state < RXRPC_CALL_COMPLETE) {
 420                         skb_queue_tail(&call->rx_queue, skb);
 421                         rxrpc_queue_call(call);
 422                         skb = NULL;
 423                 }
 424                 read_unlock_bh(&call->state_lock);
 425                 goto free_packet;
 426         }
 427
 428 protocol_error:
 429         _debug("protocol error");
 430         write_lock_bh(&call->state_lock);
 431 protocol_error_locked:
 432         if (__rxrpc_abort_call("FPR", call, 0, RX_PROTOCOL_ERROR, EPROTO))
 433                 rxrpc_queue_call(call);
 434 free_packet_unlock:
 435         write_unlock_bh(&call->state_lock);
 436 free_packet:
 437         rxrpc_free_skb(skb);
 438 done:
 439         _leave("");
 440 }
 441
 442 /*
 443  * split up a jumbo data packet
 444  */
 445 static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
 446                                        struct sk_buff *jumbo)
 447 {
 448         struct rxrpc_jumbo_header jhdr;
 449         struct rxrpc_skb_priv *sp;
 450         struct sk_buff *part;
 451
 452         _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
 453
 454         sp = rxrpc_skb(jumbo);
 455
 456         do {
 457                 sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
 458
 459                 /* make a clone to represent the first subpacket in what's left
 460                  * of the jumbo packet */
 461                 part = skb_clone(jumbo, GFP_ATOMIC);
 462                 if (!part) {
 463                         /* simply ditch the tail in the event of ENOMEM */
 464                         pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
 465                         break;
 466                 }
 467                 rxrpc_new_skb(part);
 468
 469                 pskb_trim(part, RXRPC_JUMBO_DATALEN);
 470
 471                 if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
 472                         goto protocol_error;
 473
 474                 if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
 475                         goto protocol_error;
 476                 if (!pskb_pull(jumbo, sizeof(jhdr)))
 477                         BUG();
 478
 479                 sp->hdr.seq     += 1;
 480                 sp->hdr.serial  += 1;
 481                 sp->hdr.flags   = jhdr.flags;
 482                 sp->hdr._rsvd   = ntohs(jhdr._rsvd);
 483
 484                 _proto("Rx DATA Jumbo %%%u", sp->hdr.serial - 1);
 485
 486                 rxrpc_fast_process_packet(call, part);
 487                 part = NULL;
 488
 489         } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
 490
 491         rxrpc_fast_process_packet(call, jumbo);
 492         _leave("");
 493         return;
 494
 495 protocol_error:
 496         _debug("protocol error");
 497         rxrpc_free_skb(part);
 498         if (rxrpc_abort_call("PJP", call, sp->hdr.seq,
 499                              RX_PROTOCOL_ERROR, EPROTO))
 500                 rxrpc_queue_call(call);
 501         rxrpc_free_skb(jumbo);
 502         _leave("");
 503 }
 504
 505 /*
 506  * post an incoming packet to the appropriate call/socket to deal with
 507  * - must get rid of the sk_buff, either by freeing it or by queuing it
 508  */
 509 static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
 510                                       struct rxrpc_call *call,
 511                                       struct sk_buff *skb)
 512 {
 513         struct rxrpc_skb_priv *sp;
 514
 515         _enter("%p,%p", call, skb);
 516
 517         sp = rxrpc_skb(skb);
 518
 519         _debug("extant call [%d]", call->state);
 520
 521         read_lock(&call->state_lock);
 522         switch (call->state) {
 523         case RXRPC_CALL_COMPLETE:
 524                 switch (call->completion) {
 525                 case RXRPC_CALL_LOCALLY_ABORTED:
 526                         if (!test_and_set_bit(RXRPC_CALL_EV_ABORT,
 527                                               &call->events)) {
 528                                 rxrpc_queue_call(call);
 529                                 goto free_unlock;
 530                         }
 531                 default:
 532                         goto dead_call;
 533                 case RXRPC_CALL_SUCCEEDED:
 534                         if (rxrpc_is_service_call(call))
 535                                 goto dead_call;
 536                         goto resend_final_ack;
 537                 }
 538
 539         case RXRPC_CALL_CLIENT_FINAL_ACK:
 540                 goto resend_final_ack;
 541
 542         default:
 543                 break;
 544         }
 545
 546         read_unlock(&call->state_lock);
 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         goto done;
 555
 556 resend_final_ack:
 557         _debug("final ack again");
 558         set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
 559         rxrpc_queue_call(call);
 560         goto free_unlock;
 561
 562 dead_call:
 563         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 564                 skb->priority = RX_CALL_DEAD;
 565                 rxrpc_reject_packet(conn->params.local, skb);
 566                 goto unlock;
 567         }
 568 free_unlock:
 569         rxrpc_free_skb(skb);
 570 unlock:
 571         read_unlock(&call->state_lock);
 572 done:
 573         _leave("");
 574 }
 575
 576 /*
 577  * post connection-level events to the connection
 578  * - this includes challenges, responses, some aborts and call terminal packet
 579  *   retransmission.
 580  */
 581 static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 582                                       struct sk_buff *skb)
 583 {
 584         _enter("%p,%p", conn, skb);
 585
 586         skb_queue_tail(&conn->rx_queue, skb);
 587         rxrpc_queue_conn(conn);
 588 }
 589
 590 /*
 591  * post endpoint-level events to the local endpoint
 592  * - this includes debug and version messages
 593  */
 594 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 595                                        struct sk_buff *skb)
 596 {
 597         _enter("%p,%p", local, skb);
 598
 599         skb_queue_tail(&local->event_queue, skb);
 600         rxrpc_queue_local(local);
 601 }
 602
 603 /*
 604  * Extract the wire header from a packet and translate the byte order.
 605  */
 606 static noinline
 607 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 608 {
 609         struct rxrpc_wire_header whdr;
 610
 611         /* dig out the RxRPC connection details */
 612         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 613                 return -EBADMSG;
 614         if (!pskb_pull(skb, sizeof(whdr)))
 615                 BUG();
 616
 617         memset(sp, 0, sizeof(*sp));
 618         sp->hdr.epoch           = ntohl(whdr.epoch);
 619         sp->hdr.cid             = ntohl(whdr.cid);
 620         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 621         sp->hdr.seq             = ntohl(whdr.seq);
 622         sp->hdr.serial          = ntohl(whdr.serial);
 623         sp->hdr.flags           = whdr.flags;
 624         sp->hdr.type            = whdr.type;
 625         sp->hdr.userStatus      = whdr.userStatus;
 626         sp->hdr.securityIndex   = whdr.securityIndex;
 627         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 628         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 629         return 0;
 630 }
 631
 632 /*
 633  * handle data received on the local endpoint
 634  * - may be called in interrupt context
 635  *
 636  * The socket is locked by the caller and this prevents the socket from being
 637  * shut down and the local endpoint from going away, thus sk_user_data will not
 638  * be cleared until this function returns.
 639  */
 640 void rxrpc_data_ready(struct sock *sk)
 641 {
 642         struct rxrpc_connection *conn;
 643         struct rxrpc_skb_priv *sp;
 644         struct rxrpc_local *local = sk->sk_user_data;
 645         struct sk_buff *skb;
 646         int ret, skew;
 647
 648         _enter("%p", sk);
 649
 650         ASSERT(!irqs_disabled());
 651
 652         skb = skb_recv_datagram(sk, 0, 1, &ret);
 653         if (!skb) {
 654                 if (ret == -EAGAIN)
 655                         return;
 656                 _debug("UDP socket error %d", ret);
 657                 return;
 658         }
 659
 660         rxrpc_new_skb(skb);
 661
 662         _net("recv skb %p", skb);
 663
 664         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 665         if (skb_checksum_complete(skb)) {
 666                 rxrpc_free_skb(skb);
 667                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
 668                 _leave(" [CSUM failed]");
 669                 return;
 670         }
 671
 672         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
 673
 674         /* The socket buffer we have is owned by UDP, with UDP's data all over
 675          * it, but we really want our own data there.
 676          */
 677         skb_orphan(skb);
 678         sp = rxrpc_skb(skb);
 679
 680         _net("Rx UDP packet from %08x:%04hu",
 681              ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 682
 683         /* dig out the RxRPC connection details */
 684         if (rxrpc_extract_header(sp, skb) < 0)
 685                 goto bad_message;
 686
 687         _net("Rx RxRPC %s ep=%x call=%x:%x",
 688              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 689              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 690
 691         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 692             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 693                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 694                 goto bad_message;
 695         }
 696
 697         if (sp->hdr.type == RXRPC_PACKET_TYPE_VERSION) {
 698                 rxrpc_post_packet_to_local(local, skb);
 699                 goto out;
 700         }
 701
 702         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 703             (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 704                 goto bad_message;
 705
 706         rcu_read_lock();
 707
 708         conn = rxrpc_find_connection_rcu(local, skb);
 709         if (!conn) {
 710                 skb->priority = 0;
 711                 goto cant_route_call;
 712         }
 713
 714         /* Note the serial number skew here */
 715         skew = (int)sp->hdr.serial - (int)conn->hi_serial;
 716         if (skew >= 0) {
 717                 if (skew > 0)
 718                         conn->hi_serial = sp->hdr.serial;
 719                 skb->priority = 0;
 720         } else {
 721                 skew = -skew;
 722                 skb->priority = min(skew, 65535);
 723         }
 724
 725         if (sp->hdr.callNumber == 0) {
 726                 /* Connection-level packet */
 727                 _debug("CONN %p {%d}", conn, conn->debug_id);
 728                 rxrpc_post_packet_to_conn(conn, skb);
 729                 goto out_unlock;
 730         } else {
 731                 /* Call-bound packets are routed by connection channel. */
 732                 unsigned int channel = sp->hdr.cid & RXRPC_CHANNELMASK;
 733                 struct rxrpc_channel *chan = &conn->channels[channel];
 734                 struct rxrpc_call *call;
 735
 736                 /* Ignore really old calls */
 737                 if (sp->hdr.callNumber < chan->last_call)
 738                         goto discard_unlock;
 739
 740                 if (sp->hdr.callNumber == chan->last_call) {
 741                         /* For the previous service call, if completed
 742                          * successfully, we discard all further packets.
 743                          */
 744                         if (rxrpc_conn_is_service(conn) &&
 745                             (chan->last_type == RXRPC_PACKET_TYPE_ACK ||
 746                              sp->hdr.type == RXRPC_PACKET_TYPE_ABORT))
 747                                 goto discard_unlock;
 748
 749                         /* But otherwise we need to retransmit the final packet
 750                          * from data cached in the connection record.
 751                          */
 752                         rxrpc_post_packet_to_conn(conn, skb);
 753                         goto out_unlock;
 754                 }
 755
 756                 call = rcu_dereference(chan->call);
 757                 if (!call || atomic_read(&call->usage) == 0)
 758                         goto cant_route_call;
 759
 760                 rxrpc_see_call(call);
 761                 rxrpc_post_packet_to_call(conn, call, skb);
 762                 goto out_unlock;
 763         }
 764
 765 discard_unlock:
 766         rxrpc_free_skb(skb);
 767 out_unlock:
 768         rcu_read_unlock();
 769 out:
 770         return;
 771
 772 cant_route_call:
 773         rcu_read_unlock();
 774
 775         _debug("can't route call");
 776         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 777             sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 778                 if (sp->hdr.seq == 1) {
 779                         _debug("first packet");
 780                         skb_queue_tail(&local->accept_queue, skb);
 781                         rxrpc_queue_work(&local->processor);
 782                         _leave(" [incoming]");
 783                         return;
 784                 }
 785                 skb->priority = RX_INVALID_OPERATION;
 786         } else {
 787                 skb->priority = RX_CALL_DEAD;
 788         }
 789
 790         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 791                 _debug("reject type %d",sp->hdr.type);
 792                 rxrpc_reject_packet(local, skb);
 793         } else {
 794                 rxrpc_free_skb(skb);
 795         }
 796         _leave(" [no call]");
 797         return;
 798
 799 bad_message:
 800         skb->priority = RX_PROTOCOL_ERROR;
 801         rxrpc_reject_packet(local, skb);
 802         _leave(" [badmsg]");
 803 }