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                 skb->destructor = NULL;
  59                 sp->call = NULL;
  60                 rxrpc_put_call(call);
  61                 rxrpc_free_skb(skb);
  62                 return 0;
  63         }
  64
  65         sk = &rx->sk;
  66
  67         if (!force) {
  68                 /* cast skb->rcvbuf to unsigned...  It's pointless, but
  69                  * reduces number of warnings when compiling with -W
  70                  * --ANK */
  71 //              ret = -ENOBUFS;
  72 //              if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
  73 //                  (unsigned int) sk->sk_rcvbuf)
  74 //                      goto out;
  75
  76                 ret = sk_filter(sk, skb);
  77                 if (ret < 0)
  78                         goto out;
  79         }
  80
  81         spin_lock_bh(&sk->sk_receive_queue.lock);
  82         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
  83             !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
  84             call->socket->sk.sk_state != RXRPC_CLOSE) {
  85                 skb->destructor = rxrpc_packet_destructor;
  86                 skb->dev = NULL;
  87                 skb->sk = sk;
  88                 atomic_add(skb->truesize, &sk->sk_rmem_alloc);
  89
  90                 if (terminal) {
  91                         _debug("<<<< TERMINAL MESSAGE >>>>");
  92                         set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
  93                 }
  94
  95                 /* allow interception by a kernel service */
  96                 if (rx->interceptor) {
  97                         rx->interceptor(sk, call->user_call_ID, skb);
  98                         spin_unlock_bh(&sk->sk_receive_queue.lock);
  99                 } else {
 100                         _net("post skb %p", skb);
 101                         __skb_queue_tail(&sk->sk_receive_queue, skb);
 102                         spin_unlock_bh(&sk->sk_receive_queue.lock);
 103
 104                         if (!sock_flag(sk, SOCK_DEAD))
 105                                 sk->sk_data_ready(sk);
 106                 }
 107                 skb = NULL;
 108         } else {
 109                 spin_unlock_bh(&sk->sk_receive_queue.lock);
 110         }
 111         ret = 0;
 112
 113 out:
 114         /* release the socket buffer */
 115         if (skb) {
 116                 skb->destructor = NULL;
 117                 sp->call = NULL;
 118                 rxrpc_put_call(call);
 119                 rxrpc_free_skb(skb);
 120         }
 121
 122         _leave(" = %d", ret);
 123         return ret;
 124 }
 125
 126 /*
 127  * process a DATA packet, posting the packet to the appropriate queue
 128  * - eats the packet if successful
 129  */
 130 static int rxrpc_fast_process_data(struct rxrpc_call *call,
 131                                    struct sk_buff *skb, u32 seq)
 132 {
 133         struct rxrpc_skb_priv *sp;
 134         bool terminal;
 135         int ret, ackbit, ack;
 136
 137         _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
 138
 139         sp = rxrpc_skb(skb);
 140         ASSERTCMP(sp->call, ==, NULL);
 141
 142         spin_lock(&call->lock);
 143
 144         if (call->state > RXRPC_CALL_COMPLETE)
 145                 goto discard;
 146
 147         ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
 148         ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
 149         ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
 150
 151         if (seq < call->rx_data_post) {
 152                 _debug("dup #%u [-%u]", seq, call->rx_data_post);
 153                 ack = RXRPC_ACK_DUPLICATE;
 154                 ret = -ENOBUFS;
 155                 goto discard_and_ack;
 156         }
 157
 158         /* we may already have the packet in the out of sequence queue */
 159         ackbit = seq - (call->rx_data_eaten + 1);
 160         ASSERTCMP(ackbit, >=, 0);
 161         if (__test_and_set_bit(ackbit, call->ackr_window)) {
 162                 _debug("dup oos #%u [%u,%u]",
 163                        seq, call->rx_data_eaten, call->rx_data_post);
 164                 ack = RXRPC_ACK_DUPLICATE;
 165                 goto discard_and_ack;
 166         }
 167
 168         if (seq >= call->ackr_win_top) {
 169                 _debug("exceed #%u [%u]", seq, call->ackr_win_top);
 170                 __clear_bit(ackbit, call->ackr_window);
 171                 ack = RXRPC_ACK_EXCEEDS_WINDOW;
 172                 goto discard_and_ack;
 173         }
 174
 175         if (seq == call->rx_data_expect) {
 176                 clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
 177                 call->rx_data_expect++;
 178         } else if (seq > call->rx_data_expect) {
 179                 _debug("oos #%u [%u]", seq, call->rx_data_expect);
 180                 call->rx_data_expect = seq + 1;
 181                 if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
 182                         ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 183                         goto enqueue_and_ack;
 184                 }
 185                 goto enqueue_packet;
 186         }
 187
 188         if (seq != call->rx_data_post) {
 189                 _debug("ahead #%u [%u]", seq, call->rx_data_post);
 190                 goto enqueue_packet;
 191         }
 192
 193         if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
 194                 goto protocol_error;
 195
 196         /* if the packet need security things doing to it, then it goes down
 197          * the slow path */
 198         if (call->conn->security_ix)
 199                 goto enqueue_packet;
 200
 201         sp->call = call;
 202         rxrpc_get_call(call);
 203         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 204                     !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 205         ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
 206         if (ret < 0) {
 207                 if (ret == -ENOMEM || ret == -ENOBUFS) {
 208                         __clear_bit(ackbit, call->ackr_window);
 209                         ack = RXRPC_ACK_NOSPACE;
 210                         goto discard_and_ack;
 211                 }
 212                 goto out;
 213         }
 214
 215         skb = NULL;
 216
 217         _debug("post #%u", seq);
 218         ASSERTCMP(call->rx_data_post, ==, seq);
 219         call->rx_data_post++;
 220
 221         if (sp->hdr.flags & RXRPC_LAST_PACKET)
 222                 set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);
 223
 224         /* if we've reached an out of sequence packet then we need to drain
 225          * that queue into the socket Rx queue now */
 226         if (call->rx_data_post == call->rx_first_oos) {
 227                 _debug("drain rx oos now");
 228                 read_lock(&call->state_lock);
 229                 if (call->state < RXRPC_CALL_COMPLETE &&
 230                     !test_and_set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events))
 231                         rxrpc_queue_call(call);
 232                 read_unlock(&call->state_lock);
 233         }
 234
 235         spin_unlock(&call->lock);
 236         atomic_inc(&call->ackr_not_idle);
 237         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, sp->hdr.serial, false);
 238         _leave(" = 0 [posted]");
 239         return 0;
 240
 241 protocol_error:
 242         ret = -EBADMSG;
 243 out:
 244         spin_unlock(&call->lock);
 245         _leave(" = %d", ret);
 246         return ret;
 247
 248 discard_and_ack:
 249         _debug("discard and ACK packet %p", skb);
 250         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
 251 discard:
 252         spin_unlock(&call->lock);
 253         rxrpc_free_skb(skb);
 254         _leave(" = 0 [discarded]");
 255         return 0;
 256
 257 enqueue_and_ack:
 258         __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
 259 enqueue_packet:
 260         _net("defer skb %p", skb);
 261         spin_unlock(&call->lock);
 262         skb_queue_tail(&call->rx_queue, skb);
 263         atomic_inc(&call->ackr_not_idle);
 264         read_lock(&call->state_lock);
 265         if (call->state < RXRPC_CALL_DEAD)
 266                 rxrpc_queue_call(call);
 267         read_unlock(&call->state_lock);
 268         _leave(" = 0 [queued]");
 269         return 0;
 270 }
 271
 272 /*
 273  * assume an implicit ACKALL of the transmission phase of a client socket upon
 274  * reception of the first reply packet
 275  */
 276 static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
 277 {
 278         write_lock_bh(&call->state_lock);
 279
 280         switch (call->state) {
 281         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 282                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 283                 call->acks_latest = serial;
 284
 285                 _debug("implicit ACKALL %%%u", call->acks_latest);
 286                 set_bit(RXRPC_CALL_EV_RCVD_ACKALL, &call->events);
 287                 write_unlock_bh(&call->state_lock);
 288
 289                 if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
 290                         clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
 291                         clear_bit(RXRPC_CALL_EV_RESEND, &call->events);
 292                         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 293                 }
 294                 break;
 295
 296         default:
 297                 write_unlock_bh(&call->state_lock);
 298                 break;
 299         }
 300 }
 301
 302 /*
 303  * post an incoming packet to the nominated call to deal with
 304  * - must get rid of the sk_buff, either by freeing it or by queuing it
 305  */
 306 void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
 307 {
 308         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 309         __be32 wtmp;
 310         u32 hi_serial, abort_code;
 311
 312         _enter("%p,%p", call, skb);
 313
 314         ASSERT(!irqs_disabled());
 315
 316 #if 0 // INJECT RX ERROR
 317         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 318                 static int skip = 0;
 319                 if (++skip == 3) {
 320                         printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
 321                         skip = 0;
 322                         goto free_packet;
 323                 }
 324         }
 325 #endif
 326
 327         /* track the latest serial number on this connection for ACK packet
 328          * information */
 329         hi_serial = atomic_read(&call->conn->hi_serial);
 330         while (sp->hdr.serial > hi_serial)
 331                 hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
 332                                            sp->hdr.serial);
 333
 334         /* request ACK generation for any ACK or DATA packet that requests
 335          * it */
 336         if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 337                 _proto("ACK Requested on %%%u", sp->hdr.serial);
 338                 rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial, false);
 339         }
 340
 341         switch (sp->hdr.type) {
 342         case RXRPC_PACKET_TYPE_ABORT:
 343                 _debug("abort");
 344
 345                 if (skb_copy_bits(skb, 0, &wtmp, sizeof(wtmp)) < 0)
 346                         goto protocol_error;
 347
 348                 abort_code = ntohl(wtmp);
 349                 _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
 350
 351                 write_lock_bh(&call->state_lock);
 352                 if (call->state < RXRPC_CALL_COMPLETE) {
 353                         call->state = RXRPC_CALL_REMOTELY_ABORTED;
 354                         call->remote_abort = abort_code;
 355                         set_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
 356                         rxrpc_queue_call(call);
 357                 }
 358                 goto free_packet_unlock;
 359
 360         case RXRPC_PACKET_TYPE_BUSY:
 361                 _proto("Rx BUSY %%%u", sp->hdr.serial);
 362
 363                 if (rxrpc_conn_is_service(call->conn))
 364                         goto protocol_error;
 365
 366                 write_lock_bh(&call->state_lock);
 367                 switch (call->state) {
 368                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 369                         call->state = RXRPC_CALL_SERVER_BUSY;
 370                         set_bit(RXRPC_CALL_EV_RCVD_BUSY, &call->events);
 371                         rxrpc_queue_call(call);
 372                 case RXRPC_CALL_SERVER_BUSY:
 373                         goto free_packet_unlock;
 374                 default:
 375                         goto protocol_error_locked;
 376                 }
 377
 378         default:
 379                 _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
 380                 goto protocol_error;
 381
 382         case RXRPC_PACKET_TYPE_DATA:
 383                 _proto("Rx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
 384
 385                 if (sp->hdr.seq == 0)
 386                         goto protocol_error;
 387
 388                 call->ackr_prev_seq = sp->hdr.seq;
 389
 390                 /* received data implicitly ACKs all of the request packets we
 391                  * sent when we're acting as a client */
 392                 if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 393                         rxrpc_assume_implicit_ackall(call, sp->hdr.serial);
 394
 395                 switch (rxrpc_fast_process_data(call, skb, sp->hdr.seq)) {
 396                 case 0:
 397                         skb = NULL;
 398                         goto done;
 399
 400                 default:
 401                         BUG();
 402
 403                         /* data packet received beyond the last packet */
 404                 case -EBADMSG:
 405                         goto protocol_error;
 406                 }
 407
 408         case RXRPC_PACKET_TYPE_ACKALL:
 409         case RXRPC_PACKET_TYPE_ACK:
 410                 /* ACK processing is done in process context */
 411                 read_lock_bh(&call->state_lock);
 412                 if (call->state < RXRPC_CALL_DEAD) {
 413                         skb_queue_tail(&call->rx_queue, skb);
 414                         rxrpc_queue_call(call);
 415                         skb = NULL;
 416                 }
 417                 read_unlock_bh(&call->state_lock);
 418                 goto free_packet;
 419         }
 420
 421 protocol_error:
 422         _debug("protocol error");
 423         write_lock_bh(&call->state_lock);
 424 protocol_error_locked:
 425         if (call->state <= RXRPC_CALL_COMPLETE) {
 426                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 427                 call->local_abort = RX_PROTOCOL_ERROR;
 428                 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
 429                 rxrpc_queue_call(call);
 430         }
 431 free_packet_unlock:
 432         write_unlock_bh(&call->state_lock);
 433 free_packet:
 434         rxrpc_free_skb(skb);
 435 done:
 436         _leave("");
 437 }
 438
 439 /*
 440  * split up a jumbo data packet
 441  */
 442 static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
 443                                        struct sk_buff *jumbo)
 444 {
 445         struct rxrpc_jumbo_header jhdr;
 446         struct rxrpc_skb_priv *sp;
 447         struct sk_buff *part;
 448
 449         _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
 450
 451         sp = rxrpc_skb(jumbo);
 452
 453         do {
 454                 sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
 455
 456                 /* make a clone to represent the first subpacket in what's left
 457                  * of the jumbo packet */
 458                 part = skb_clone(jumbo, GFP_ATOMIC);
 459                 if (!part) {
 460                         /* simply ditch the tail in the event of ENOMEM */
 461                         pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
 462                         break;
 463                 }
 464                 rxrpc_new_skb(part);
 465
 466                 pskb_trim(part, RXRPC_JUMBO_DATALEN);
 467
 468                 if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
 469                         goto protocol_error;
 470
 471                 if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
 472                         goto protocol_error;
 473                 if (!pskb_pull(jumbo, sizeof(jhdr)))
 474                         BUG();
 475
 476                 sp->hdr.seq     += 1;
 477                 sp->hdr.serial  += 1;
 478                 sp->hdr.flags   = jhdr.flags;
 479                 sp->hdr._rsvd   = ntohs(jhdr._rsvd);
 480
 481                 _proto("Rx DATA Jumbo %%%u", sp->hdr.serial - 1);
 482
 483                 rxrpc_fast_process_packet(call, part);
 484                 part = NULL;
 485
 486         } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
 487
 488         rxrpc_fast_process_packet(call, jumbo);
 489         _leave("");
 490         return;
 491
 492 protocol_error:
 493         _debug("protocol error");
 494         rxrpc_free_skb(part);
 495         rxrpc_free_skb(jumbo);
 496         write_lock_bh(&call->state_lock);
 497         if (call->state <= RXRPC_CALL_COMPLETE) {
 498                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 499                 call->local_abort = RX_PROTOCOL_ERROR;
 500                 set_bit(RXRPC_CALL_EV_ABORT, &call->events);
 501                 rxrpc_queue_call(call);
 502         }
 503         write_unlock_bh(&call->state_lock);
 504         _leave("");
 505 }
 506
 507 /*
 508  * post an incoming packet to the appropriate call/socket to deal with
 509  * - must get rid of the sk_buff, either by freeing it or by queuing it
 510  */
 511 static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
 512                                       struct sk_buff *skb)
 513 {
 514         struct rxrpc_skb_priv *sp;
 515
 516         _enter("%p,%p", call, skb);
 517
 518         sp = rxrpc_skb(skb);
 519
 520         _debug("extant call [%d]", call->state);
 521
 522         read_lock(&call->state_lock);
 523         switch (call->state) {
 524         case RXRPC_CALL_LOCALLY_ABORTED:
 525                 if (!test_and_set_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
 526                         rxrpc_queue_call(call);
 527                         goto free_unlock;
 528                 }
 529         case RXRPC_CALL_REMOTELY_ABORTED:
 530         case RXRPC_CALL_NETWORK_ERROR:
 531         case RXRPC_CALL_DEAD:
 532                 goto dead_call;
 533         case RXRPC_CALL_COMPLETE:
 534         case RXRPC_CALL_CLIENT_FINAL_ACK:
 535                 /* complete server call */
 536                 if (rxrpc_conn_is_service(call->conn))
 537                         goto dead_call;
 538                 /* resend last packet of a completed call */
 539                 _debug("final ack again");
 540                 rxrpc_get_call(call);
 541                 set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
 542                 rxrpc_queue_call(call);
 543                 goto free_unlock;
 544         default:
 545                 break;
 546         }
 547
 548         read_unlock(&call->state_lock);
 549         rxrpc_get_call(call);
 550
 551         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 552             sp->hdr.flags & RXRPC_JUMBO_PACKET)
 553                 rxrpc_process_jumbo_packet(call, skb);
 554         else
 555                 rxrpc_fast_process_packet(call, skb);
 556
 557         rxrpc_put_call(call);
 558         goto done;
 559
 560 dead_call:
 561         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 562                 skb->priority = RX_CALL_DEAD;
 563                 rxrpc_reject_packet(call->conn->params.local, skb);
 564                 goto unlock;
 565         }
 566 free_unlock:
 567         rxrpc_free_skb(skb);
 568 unlock:
 569         read_unlock(&call->state_lock);
 570 done:
 571         _leave("");
 572 }
 573
 574 /*
 575  * post connection-level events to the connection
 576  * - this includes challenges, responses and some aborts
 577  */
 578 static bool rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 579                                       struct sk_buff *skb)
 580 {
 581         _enter("%p,%p", conn, skb);
 582
 583         skb_queue_tail(&conn->rx_queue, skb);
 584         return rxrpc_queue_conn(conn);
 585 }
 586
 587 /*
 588  * post endpoint-level events to the local endpoint
 589  * - this includes debug and version messages
 590  */
 591 static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
 592                                        struct sk_buff *skb)
 593 {
 594         _enter("%p,%p", local, skb);
 595
 596         skb_queue_tail(&local->event_queue, skb);
 597         rxrpc_queue_local(local);
 598 }
 599
 600 /*
 601  * Extract the wire header from a packet and translate the byte order.
 602  */
 603 static noinline
 604 int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 605 {
 606         struct rxrpc_wire_header whdr;
 607
 608         /* dig out the RxRPC connection details */
 609         if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
 610                 return -EBADMSG;
 611         if (!pskb_pull(skb, sizeof(whdr)))
 612                 BUG();
 613
 614         memset(sp, 0, sizeof(*sp));
 615         sp->hdr.epoch           = ntohl(whdr.epoch);
 616         sp->hdr.cid             = ntohl(whdr.cid);
 617         sp->hdr.callNumber      = ntohl(whdr.callNumber);
 618         sp->hdr.seq             = ntohl(whdr.seq);
 619         sp->hdr.serial          = ntohl(whdr.serial);
 620         sp->hdr.flags           = whdr.flags;
 621         sp->hdr.type            = whdr.type;
 622         sp->hdr.userStatus      = whdr.userStatus;
 623         sp->hdr.securityIndex   = whdr.securityIndex;
 624         sp->hdr._rsvd           = ntohs(whdr._rsvd);
 625         sp->hdr.serviceId       = ntohs(whdr.serviceId);
 626         return 0;
 627 }
 628
 629 /*
 630  * handle data received on the local endpoint
 631  * - may be called in interrupt context
 632  *
 633  * The socket is locked by the caller and this prevents the socket from being
 634  * shut down and the local endpoint from going away, thus sk_user_data will not
 635  * be cleared until this function returns.
 636  */
 637 void rxrpc_data_ready(struct sock *sk)
 638 {
 639         struct rxrpc_connection *conn;
 640         struct rxrpc_skb_priv *sp;
 641         struct rxrpc_local *local = sk->sk_user_data;
 642         struct sk_buff *skb;
 643         int ret;
 644
 645         _enter("%p", sk);
 646
 647         ASSERT(!irqs_disabled());
 648
 649         skb = skb_recv_datagram(sk, 0, 1, &ret);
 650         if (!skb) {
 651                 if (ret == -EAGAIN)
 652                         return;
 653                 _debug("UDP socket error %d", ret);
 654                 return;
 655         }
 656
 657         rxrpc_new_skb(skb);
 658
 659         _net("recv skb %p", skb);
 660
 661         /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 662         if (skb_checksum_complete(skb)) {
 663                 rxrpc_free_skb(skb);
 664                 __UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
 665                 _leave(" [CSUM failed]");
 666                 return;
 667         }
 668
 669         __UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
 670
 671         /* The socket buffer we have is owned by UDP, with UDP's data all over
 672          * it, but we really want our own data there.
 673          */
 674         skb_orphan(skb);
 675         sp = rxrpc_skb(skb);
 676
 677         _net("Rx UDP packet from %08x:%04hu",
 678              ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 679
 680         /* dig out the RxRPC connection details */
 681         if (rxrpc_extract_header(sp, skb) < 0)
 682                 goto bad_message;
 683
 684         _net("Rx RxRPC %s ep=%x call=%x:%x",
 685              sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 686              sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
 687
 688         if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
 689             !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
 690                 _proto("Rx Bad Packet Type %u", sp->hdr.type);
 691                 goto bad_message;
 692         }
 693
 694         if (sp->hdr.type == RXRPC_PACKET_TYPE_VERSION) {
 695                 rxrpc_post_packet_to_local(local, skb);
 696                 goto out;
 697         }
 698
 699         if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 700             (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 701                 goto bad_message;
 702
 703         rcu_read_lock();
 704
 705 retry_find_conn:
 706         conn = rxrpc_find_connection_rcu(local, skb);
 707         if (!conn)
 708                 goto cant_route_call;
 709
 710         if (sp->hdr.callNumber == 0) {
 711                 /* Connection-level packet */
 712                 _debug("CONN %p {%d}", conn, conn->debug_id);
 713                 if (!rxrpc_post_packet_to_conn(conn, skb))
 714                         goto retry_find_conn;
 715         } else {
 716                 /* Call-bound packets are routed by connection channel. */
 717                 unsigned int channel = sp->hdr.cid & RXRPC_CHANNELMASK;
 718                 struct rxrpc_channel *chan = &conn->channels[channel];
 719                 struct rxrpc_call *call = rcu_dereference(chan->call);
 720
 721                 if (!call || atomic_read(&call->usage) == 0)
 722                         goto cant_route_call;
 723
 724                 rxrpc_post_packet_to_call(call, skb);
 725         }
 726
 727         rcu_read_unlock();
 728 out:
 729         return;
 730
 731 cant_route_call:
 732         rcu_read_unlock();
 733
 734         _debug("can't route call");
 735         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 736             sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 737                 if (sp->hdr.seq == 1) {
 738                         _debug("first packet");
 739                         skb_queue_tail(&local->accept_queue, skb);
 740                         rxrpc_queue_work(&local->processor);
 741                         _leave(" [incoming]");
 742                         return;
 743                 }
 744                 skb->priority = RX_INVALID_OPERATION;
 745         } else {
 746                 skb->priority = RX_CALL_DEAD;
 747         }
 748
 749         if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
 750                 _debug("reject type %d",sp->hdr.type);
 751                 rxrpc_reject_packet(local, skb);
 752         }
 753         _leave(" [no call]");
 754         return;
 755
 756 bad_message:
 757         skb->priority = RX_PROTOCOL_ERROR;
 758         rxrpc_reject_packet(local, skb);
 759         _leave(" [badmsg]");
 760 }