linux/net/rxrpc/ar-input.c
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   1/* RxRPC packet reception
   2 *
   3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/net.h>
  14#include <linux/skbuff.h>
  15#include <linux/errqueue.h>
  16#include <linux/udp.h>
  17#include <linux/in.h>
  18#include <linux/in6.h>
  19#include <linux/icmp.h>
  20#include <linux/gfp.h>
  21#include <net/sock.h>
  22#include <net/af_rxrpc.h>
  23#include <net/ip.h>
  24#include <net/udp.h>
  25#include <net/net_namespace.h>
  26#include "ar-internal.h"
  27
  28unsigned long rxrpc_ack_timeout = 1;
  29
  30const char *rxrpc_pkts[] = {
  31        "?00",
  32        "DATA", "ACK", "BUSY", "ABORT", "ACKALL", "CHALL", "RESP", "DEBUG",
  33        "?09", "?10", "?11", "?12", "?13", "?14", "?15"
  34};
  35
  36/*
  37 * queue a packet for recvmsg to pass to userspace
  38 * - the caller must hold a lock on call->lock
  39 * - must not be called with interrupts disabled (sk_filter() disables BH's)
  40 * - eats the packet whether successful or not
  41 * - there must be just one reference to the packet, which the caller passes to
  42 *   this function
  43 */
  44int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
  45                        bool force, bool terminal)
  46{
  47        struct rxrpc_skb_priv *sp;
  48        struct rxrpc_sock *rx = call->socket;
  49        struct sock *sk;
  50        int skb_len, ret;
  51
  52        _enter(",,%d,%d", force, terminal);
  53
  54        ASSERT(!irqs_disabled());
  55
  56        sp = rxrpc_skb(skb);
  57        ASSERTCMP(sp->call, ==, call);
  58
  59        /* if we've already posted the terminal message for a call, then we
  60         * don't post any more */
  61        if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
  62                _debug("already terminated");
  63                ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
  64                skb->destructor = NULL;
  65                sp->call = NULL;
  66                rxrpc_put_call(call);
  67                rxrpc_free_skb(skb);
  68                return 0;
  69        }
  70
  71        sk = &rx->sk;
  72
  73        if (!force) {
  74                /* cast skb->rcvbuf to unsigned...  It's pointless, but
  75                 * reduces number of warnings when compiling with -W
  76                 * --ANK */
  77//              ret = -ENOBUFS;
  78//              if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
  79//                  (unsigned) sk->sk_rcvbuf)
  80//                      goto out;
  81
  82                ret = sk_filter(sk, skb);
  83                if (ret < 0)
  84                        goto out;
  85        }
  86
  87        spin_lock_bh(&sk->sk_receive_queue.lock);
  88        if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
  89            !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
  90            call->socket->sk.sk_state != RXRPC_CLOSE) {
  91                skb->destructor = rxrpc_packet_destructor;
  92                skb->dev = NULL;
  93                skb->sk = sk;
  94                atomic_add(skb->truesize, &sk->sk_rmem_alloc);
  95
  96                if (terminal) {
  97                        _debug("<<<< TERMINAL MESSAGE >>>>");
  98                        set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
  99                }
 100
 101                /* allow interception by a kernel service */
 102                if (rx->interceptor) {
 103                        rx->interceptor(sk, call->user_call_ID, skb);
 104                        spin_unlock_bh(&sk->sk_receive_queue.lock);
 105                } else {
 106
 107                        /* Cache the SKB length before we tack it onto the
 108                         * receive queue.  Once it is added it no longer
 109                         * belongs to us and may be freed by other threads of
 110                         * control pulling packets from the queue */
 111                        skb_len = skb->len;
 112
 113                        _net("post skb %p", skb);
 114                        __skb_queue_tail(&sk->sk_receive_queue, skb);
 115                        spin_unlock_bh(&sk->sk_receive_queue.lock);
 116
 117                        if (!sock_flag(sk, SOCK_DEAD))
 118                                sk->sk_data_ready(sk, skb_len);
 119                }
 120                skb = NULL;
 121        } else {
 122                spin_unlock_bh(&sk->sk_receive_queue.lock);
 123        }
 124        ret = 0;
 125
 126out:
 127        /* release the socket buffer */
 128        if (skb) {
 129                skb->destructor = NULL;
 130                sp->call = NULL;
 131                rxrpc_put_call(call);
 132                rxrpc_free_skb(skb);
 133        }
 134
 135        _leave(" = %d", ret);
 136        return ret;
 137}
 138
 139/*
 140 * process a DATA packet, posting the packet to the appropriate queue
 141 * - eats the packet if successful
 142 */
 143static int rxrpc_fast_process_data(struct rxrpc_call *call,
 144                                   struct sk_buff *skb, u32 seq)
 145{
 146        struct rxrpc_skb_priv *sp;
 147        bool terminal;
 148        int ret, ackbit, ack;
 149
 150        _enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
 151
 152        sp = rxrpc_skb(skb);
 153        ASSERTCMP(sp->call, ==, NULL);
 154
 155        spin_lock(&call->lock);
 156
 157        if (call->state > RXRPC_CALL_COMPLETE)
 158                goto discard;
 159
 160        ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
 161        ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
 162        ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
 163
 164        if (seq < call->rx_data_post) {
 165                _debug("dup #%u [-%u]", seq, call->rx_data_post);
 166                ack = RXRPC_ACK_DUPLICATE;
 167                ret = -ENOBUFS;
 168                goto discard_and_ack;
 169        }
 170
 171        /* we may already have the packet in the out of sequence queue */
 172        ackbit = seq - (call->rx_data_eaten + 1);
 173        ASSERTCMP(ackbit, >=, 0);
 174        if (__test_and_set_bit(ackbit, call->ackr_window)) {
 175                _debug("dup oos #%u [%u,%u]",
 176                       seq, call->rx_data_eaten, call->rx_data_post);
 177                ack = RXRPC_ACK_DUPLICATE;
 178                goto discard_and_ack;
 179        }
 180
 181        if (seq >= call->ackr_win_top) {
 182                _debug("exceed #%u [%u]", seq, call->ackr_win_top);
 183                __clear_bit(ackbit, call->ackr_window);
 184                ack = RXRPC_ACK_EXCEEDS_WINDOW;
 185                goto discard_and_ack;
 186        }
 187
 188        if (seq == call->rx_data_expect) {
 189                clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
 190                call->rx_data_expect++;
 191        } else if (seq > call->rx_data_expect) {
 192                _debug("oos #%u [%u]", seq, call->rx_data_expect);
 193                call->rx_data_expect = seq + 1;
 194                if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
 195                        ack = RXRPC_ACK_OUT_OF_SEQUENCE;
 196                        goto enqueue_and_ack;
 197                }
 198                goto enqueue_packet;
 199        }
 200
 201        if (seq != call->rx_data_post) {
 202                _debug("ahead #%u [%u]", seq, call->rx_data_post);
 203                goto enqueue_packet;
 204        }
 205
 206        if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
 207                goto protocol_error;
 208
 209        /* if the packet need security things doing to it, then it goes down
 210         * the slow path */
 211        if (call->conn->security)
 212                goto enqueue_packet;
 213
 214        sp->call = call;
 215        rxrpc_get_call(call);
 216        terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 217                    !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 218        ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
 219        if (ret < 0) {
 220                if (ret == -ENOMEM || ret == -ENOBUFS) {
 221                        __clear_bit(ackbit, call->ackr_window);
 222                        ack = RXRPC_ACK_NOSPACE;
 223                        goto discard_and_ack;
 224                }
 225                goto out;
 226        }
 227
 228        skb = NULL;
 229
 230        _debug("post #%u", seq);
 231        ASSERTCMP(call->rx_data_post, ==, seq);
 232        call->rx_data_post++;
 233
 234        if (sp->hdr.flags & RXRPC_LAST_PACKET)
 235                set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);
 236
 237        /* if we've reached an out of sequence packet then we need to drain
 238         * that queue into the socket Rx queue now */
 239        if (call->rx_data_post == call->rx_first_oos) {
 240                _debug("drain rx oos now");
 241                read_lock(&call->state_lock);
 242                if (call->state < RXRPC_CALL_COMPLETE &&
 243                    !test_and_set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events))
 244                        rxrpc_queue_call(call);
 245                read_unlock(&call->state_lock);
 246        }
 247
 248        spin_unlock(&call->lock);
 249        atomic_inc(&call->ackr_not_idle);
 250        rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, sp->hdr.serial, false);
 251        _leave(" = 0 [posted]");
 252        return 0;
 253
 254protocol_error:
 255        ret = -EBADMSG;
 256out:
 257        spin_unlock(&call->lock);
 258        _leave(" = %d", ret);
 259        return ret;
 260
 261discard_and_ack:
 262        _debug("discard and ACK packet %p", skb);
 263        __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
 264discard:
 265        spin_unlock(&call->lock);
 266        rxrpc_free_skb(skb);
 267        _leave(" = 0 [discarded]");
 268        return 0;
 269
 270enqueue_and_ack:
 271        __rxrpc_propose_ACK(call, ack, sp->hdr.serial, true);
 272enqueue_packet:
 273        _net("defer skb %p", skb);
 274        spin_unlock(&call->lock);
 275        skb_queue_tail(&call->rx_queue, skb);
 276        atomic_inc(&call->ackr_not_idle);
 277        read_lock(&call->state_lock);
 278        if (call->state < RXRPC_CALL_DEAD)
 279                rxrpc_queue_call(call);
 280        read_unlock(&call->state_lock);
 281        _leave(" = 0 [queued]");
 282        return 0;
 283}
 284
 285/*
 286 * assume an implicit ACKALL of the transmission phase of a client socket upon
 287 * reception of the first reply packet
 288 */
 289static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
 290{
 291        write_lock_bh(&call->state_lock);
 292
 293        switch (call->state) {
 294        case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 295                call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 296                call->acks_latest = serial;
 297
 298                _debug("implicit ACKALL %%%u", call->acks_latest);
 299                set_bit(RXRPC_CALL_RCVD_ACKALL, &call->events);
 300                write_unlock_bh(&call->state_lock);
 301
 302                if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
 303                        clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 304                        clear_bit(RXRPC_CALL_RESEND, &call->events);
 305                        clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 306                }
 307                break;
 308
 309        default:
 310                write_unlock_bh(&call->state_lock);
 311                break;
 312        }
 313}
 314
 315/*
 316 * post an incoming packet to the nominated call to deal with
 317 * - must get rid of the sk_buff, either by freeing it or by queuing it
 318 */
 319void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
 320{
 321        struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 322        __be32 _abort_code;
 323        u32 serial, hi_serial, seq, abort_code;
 324
 325        _enter("%p,%p", call, skb);
 326
 327        ASSERT(!irqs_disabled());
 328
 329#if 0 // INJECT RX ERROR
 330        if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 331                static int skip = 0;
 332                if (++skip == 3) {
 333                        printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
 334                        skip = 0;
 335                        goto free_packet;
 336                }
 337        }
 338#endif
 339
 340        /* track the latest serial number on this connection for ACK packet
 341         * information */
 342        serial = ntohl(sp->hdr.serial);
 343        hi_serial = atomic_read(&call->conn->hi_serial);
 344        while (serial > hi_serial)
 345                hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
 346                                           serial);
 347
 348        /* request ACK generation for any ACK or DATA packet that requests
 349         * it */
 350        if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
 351                _proto("ACK Requested on %%%u", serial);
 352                rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial,
 353                                  !(sp->hdr.flags & RXRPC_MORE_PACKETS));
 354        }
 355
 356        switch (sp->hdr.type) {
 357        case RXRPC_PACKET_TYPE_ABORT:
 358                _debug("abort");
 359
 360                if (skb_copy_bits(skb, 0, &_abort_code,
 361                                  sizeof(_abort_code)) < 0)
 362                        goto protocol_error;
 363
 364                abort_code = ntohl(_abort_code);
 365                _proto("Rx ABORT %%%u { %x }", serial, abort_code);
 366
 367                write_lock_bh(&call->state_lock);
 368                if (call->state < RXRPC_CALL_COMPLETE) {
 369                        call->state = RXRPC_CALL_REMOTELY_ABORTED;
 370                        call->abort_code = abort_code;
 371                        set_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
 372                        rxrpc_queue_call(call);
 373                }
 374                goto free_packet_unlock;
 375
 376        case RXRPC_PACKET_TYPE_BUSY:
 377                _proto("Rx BUSY %%%u", serial);
 378
 379                if (call->conn->out_clientflag)
 380                        goto protocol_error;
 381
 382                write_lock_bh(&call->state_lock);
 383                switch (call->state) {
 384                case RXRPC_CALL_CLIENT_SEND_REQUEST:
 385                        call->state = RXRPC_CALL_SERVER_BUSY;
 386                        set_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
 387                        rxrpc_queue_call(call);
 388                case RXRPC_CALL_SERVER_BUSY:
 389                        goto free_packet_unlock;
 390                default:
 391                        goto protocol_error_locked;
 392                }
 393
 394        default:
 395                _proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], serial);
 396                goto protocol_error;
 397
 398        case RXRPC_PACKET_TYPE_DATA:
 399                seq = ntohl(sp->hdr.seq);
 400
 401                _proto("Rx DATA %%%u { #%u }", serial, seq);
 402
 403                if (seq == 0)
 404                        goto protocol_error;
 405
 406                call->ackr_prev_seq = sp->hdr.seq;
 407
 408                /* received data implicitly ACKs all of the request packets we
 409                 * sent when we're acting as a client */
 410                if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
 411                        rxrpc_assume_implicit_ackall(call, serial);
 412
 413                switch (rxrpc_fast_process_data(call, skb, seq)) {
 414                case 0:
 415                        skb = NULL;
 416                        goto done;
 417
 418                default:
 419                        BUG();
 420
 421                        /* data packet received beyond the last packet */
 422                case -EBADMSG:
 423                        goto protocol_error;
 424                }
 425
 426        case RXRPC_PACKET_TYPE_ACK:
 427                /* ACK processing is done in process context */
 428                read_lock_bh(&call->state_lock);
 429                if (call->state < RXRPC_CALL_DEAD) {
 430                        skb_queue_tail(&call->rx_queue, skb);
 431                        rxrpc_queue_call(call);
 432                        skb = NULL;
 433                }
 434                read_unlock_bh(&call->state_lock);
 435                goto free_packet;
 436        }
 437
 438protocol_error:
 439        _debug("protocol error");
 440        write_lock_bh(&call->state_lock);
 441protocol_error_locked:
 442        if (call->state <= RXRPC_CALL_COMPLETE) {
 443                call->state = RXRPC_CALL_LOCALLY_ABORTED;
 444                call->abort_code = RX_PROTOCOL_ERROR;
 445                set_bit(RXRPC_CALL_ABORT, &call->events);
 446                rxrpc_queue_call(call);
 447        }
 448free_packet_unlock:
 449        write_unlock_bh(&call->state_lock);
 450free_packet:
 451        rxrpc_free_skb(skb);
 452done:
 453        _leave("");
 454}
 455
 456/*
 457 * split up a jumbo data packet
 458 */
 459static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
 460                                       struct sk_buff *jumbo)
 461{
 462        struct rxrpc_jumbo_header jhdr;
 463        struct rxrpc_skb_priv *sp;
 464        struct sk_buff *part;
 465
 466        _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
 467
 468        sp = rxrpc_skb(jumbo);
 469
 470        do {
 471                sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
 472
 473                /* make a clone to represent the first subpacket in what's left
 474                 * of the jumbo packet */
 475                part = skb_clone(jumbo, GFP_ATOMIC);
 476                if (!part) {
 477                        /* simply ditch the tail in the event of ENOMEM */
 478                        pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
 479                        break;
 480                }
 481                rxrpc_new_skb(part);
 482
 483                pskb_trim(part, RXRPC_JUMBO_DATALEN);
 484
 485                if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
 486                        goto protocol_error;
 487
 488                if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
 489                        goto protocol_error;
 490                if (!pskb_pull(jumbo, sizeof(jhdr)))
 491                        BUG();
 492
 493                sp->hdr.seq     = htonl(ntohl(sp->hdr.seq) + 1);
 494                sp->hdr.serial  = htonl(ntohl(sp->hdr.serial) + 1);
 495                sp->hdr.flags   = jhdr.flags;
 496                sp->hdr._rsvd   = jhdr._rsvd;
 497
 498                _proto("Rx DATA Jumbo %%%u", ntohl(sp->hdr.serial) - 1);
 499
 500                rxrpc_fast_process_packet(call, part);
 501                part = NULL;
 502
 503        } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
 504
 505        rxrpc_fast_process_packet(call, jumbo);
 506        _leave("");
 507        return;
 508
 509protocol_error:
 510        _debug("protocol error");
 511        rxrpc_free_skb(part);
 512        rxrpc_free_skb(jumbo);
 513        write_lock_bh(&call->state_lock);
 514        if (call->state <= RXRPC_CALL_COMPLETE) {
 515                call->state = RXRPC_CALL_LOCALLY_ABORTED;
 516                call->abort_code = RX_PROTOCOL_ERROR;
 517                set_bit(RXRPC_CALL_ABORT, &call->events);
 518                rxrpc_queue_call(call);
 519        }
 520        write_unlock_bh(&call->state_lock);
 521        _leave("");
 522}
 523
 524/*
 525 * post an incoming packet to the appropriate call/socket to deal with
 526 * - must get rid of the sk_buff, either by freeing it or by queuing it
 527 */
 528static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
 529                                      struct sk_buff *skb)
 530{
 531        struct rxrpc_skb_priv *sp;
 532        struct rxrpc_call *call;
 533        struct rb_node *p;
 534        __be32 call_id;
 535
 536        _enter("%p,%p", conn, skb);
 537
 538        read_lock_bh(&conn->lock);
 539
 540        sp = rxrpc_skb(skb);
 541
 542        /* look at extant calls by channel number first */
 543        call = conn->channels[ntohl(sp->hdr.cid) & RXRPC_CHANNELMASK];
 544        if (!call || call->call_id != sp->hdr.callNumber)
 545                goto call_not_extant;
 546
 547        _debug("extant call [%d]", call->state);
 548        ASSERTCMP(call->conn, ==, conn);
 549
 550        read_lock(&call->state_lock);
 551        switch (call->state) {
 552        case RXRPC_CALL_LOCALLY_ABORTED:
 553                if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
 554                        rxrpc_queue_call(call);
 555        case RXRPC_CALL_REMOTELY_ABORTED:
 556        case RXRPC_CALL_NETWORK_ERROR:
 557        case RXRPC_CALL_DEAD:
 558                goto free_unlock;
 559        default:
 560                break;
 561        }
 562
 563        read_unlock(&call->state_lock);
 564        rxrpc_get_call(call);
 565        read_unlock_bh(&conn->lock);
 566
 567        if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 568            sp->hdr.flags & RXRPC_JUMBO_PACKET)
 569                rxrpc_process_jumbo_packet(call, skb);
 570        else
 571                rxrpc_fast_process_packet(call, skb);
 572
 573        rxrpc_put_call(call);
 574        goto done;
 575
 576call_not_extant:
 577        /* search the completed calls in case what we're dealing with is
 578         * there */
 579        _debug("call not extant");
 580
 581        call_id = sp->hdr.callNumber;
 582        p = conn->calls.rb_node;
 583        while (p) {
 584                call = rb_entry(p, struct rxrpc_call, conn_node);
 585
 586                if (call_id < call->call_id)
 587                        p = p->rb_left;
 588                else if (call_id > call->call_id)
 589                        p = p->rb_right;
 590                else
 591                        goto found_completed_call;
 592        }
 593
 594dead_call:
 595        /* it's a either a really old call that we no longer remember or its a
 596         * new incoming call */
 597        read_unlock_bh(&conn->lock);
 598
 599        if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 600            sp->hdr.seq == cpu_to_be32(1)) {
 601                _debug("incoming call");
 602                skb_queue_tail(&conn->trans->local->accept_queue, skb);
 603                rxrpc_queue_work(&conn->trans->local->acceptor);
 604                goto done;
 605        }
 606
 607        _debug("dead call");
 608        skb->priority = RX_CALL_DEAD;
 609        rxrpc_reject_packet(conn->trans->local, skb);
 610        goto done;
 611
 612        /* resend last packet of a completed call
 613         * - client calls may have been aborted or ACK'd
 614         * - server calls may have been aborted
 615         */
 616found_completed_call:
 617        _debug("completed call");
 618
 619        if (atomic_read(&call->usage) == 0)
 620                goto dead_call;
 621
 622        /* synchronise any state changes */
 623        read_lock(&call->state_lock);
 624        ASSERTIFCMP(call->state != RXRPC_CALL_CLIENT_FINAL_ACK,
 625                    call->state, >=, RXRPC_CALL_COMPLETE);
 626
 627        if (call->state == RXRPC_CALL_LOCALLY_ABORTED ||
 628            call->state == RXRPC_CALL_REMOTELY_ABORTED ||
 629            call->state == RXRPC_CALL_DEAD) {
 630                read_unlock(&call->state_lock);
 631                goto dead_call;
 632        }
 633
 634        if (call->conn->in_clientflag) {
 635                read_unlock(&call->state_lock);
 636                goto dead_call; /* complete server call */
 637        }
 638
 639        _debug("final ack again");
 640        rxrpc_get_call(call);
 641        set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
 642        rxrpc_queue_call(call);
 643
 644free_unlock:
 645        read_unlock(&call->state_lock);
 646        read_unlock_bh(&conn->lock);
 647        rxrpc_free_skb(skb);
 648done:
 649        _leave("");
 650}
 651
 652/*
 653 * post connection-level events to the connection
 654 * - this includes challenges, responses and some aborts
 655 */
 656static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 657                                      struct sk_buff *skb)
 658{
 659        _enter("%p,%p", conn, skb);
 660
 661        atomic_inc(&conn->usage);
 662        skb_queue_tail(&conn->rx_queue, skb);
 663        rxrpc_queue_conn(conn);
 664}
 665
 666/*
 667 * handle data received on the local endpoint
 668 * - may be called in interrupt context
 669 */
 670void rxrpc_data_ready(struct sock *sk, int count)
 671{
 672        struct rxrpc_connection *conn;
 673        struct rxrpc_transport *trans;
 674        struct rxrpc_skb_priv *sp;
 675        struct rxrpc_local *local;
 676        struct rxrpc_peer *peer;
 677        struct sk_buff *skb;
 678        int ret;
 679
 680        _enter("%p, %d", sk, count);
 681
 682        ASSERT(!irqs_disabled());
 683
 684        read_lock_bh(&rxrpc_local_lock);
 685        local = sk->sk_user_data;
 686        if (local && atomic_read(&local->usage) > 0)
 687                rxrpc_get_local(local);
 688        else
 689                local = NULL;
 690        read_unlock_bh(&rxrpc_local_lock);
 691        if (!local) {
 692                _leave(" [local dead]");
 693                return;
 694        }
 695
 696        skb = skb_recv_datagram(sk, 0, 1, &ret);
 697        if (!skb) {
 698                rxrpc_put_local(local);
 699                if (ret == -EAGAIN)
 700                        return;
 701                _debug("UDP socket error %d", ret);
 702                return;
 703        }
 704
 705        rxrpc_new_skb(skb);
 706
 707        _net("recv skb %p", skb);
 708
 709        /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 710        if (skb_checksum_complete(skb)) {
 711                rxrpc_free_skb(skb);
 712                rxrpc_put_local(local);
 713                UDP_INC_STATS_BH(&init_net, UDP_MIB_INERRORS, 0);
 714                _leave(" [CSUM failed]");
 715                return;
 716        }
 717
 718        UDP_INC_STATS_BH(&init_net, UDP_MIB_INDATAGRAMS, 0);
 719
 720        /* the socket buffer we have is owned by UDP, with UDP's data all over
 721         * it, but we really want our own */
 722        skb_orphan(skb);
 723        sp = rxrpc_skb(skb);
 724        memset(sp, 0, sizeof(*sp));
 725
 726        _net("Rx UDP packet from %08x:%04hu",
 727             ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 728
 729        /* dig out the RxRPC connection details */
 730        if (skb_copy_bits(skb, sizeof(struct udphdr), &sp->hdr,
 731                          sizeof(sp->hdr)) < 0)
 732                goto bad_message;
 733        if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(sp->hdr)))
 734                BUG();
 735
 736        _net("Rx RxRPC %s ep=%x call=%x:%x",
 737             sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 738             ntohl(sp->hdr.epoch),
 739             ntohl(sp->hdr.cid),
 740             ntohl(sp->hdr.callNumber));
 741
 742        if (sp->hdr.type == 0 || sp->hdr.type >= RXRPC_N_PACKET_TYPES) {
 743                _proto("Rx Bad Packet Type %u", sp->hdr.type);
 744                goto bad_message;
 745        }
 746
 747        if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 748            (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 749                goto bad_message;
 750
 751        peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr, udp_hdr(skb)->source);
 752        if (IS_ERR(peer))
 753                goto cant_route_call;
 754
 755        trans = rxrpc_find_transport(local, peer);
 756        rxrpc_put_peer(peer);
 757        if (!trans)
 758                goto cant_route_call;
 759
 760        conn = rxrpc_find_connection(trans, &sp->hdr);
 761        rxrpc_put_transport(trans);
 762        if (!conn)
 763                goto cant_route_call;
 764
 765        _debug("CONN %p {%d}", conn, conn->debug_id);
 766
 767        if (sp->hdr.callNumber == 0)
 768                rxrpc_post_packet_to_conn(conn, skb);
 769        else
 770                rxrpc_post_packet_to_call(conn, skb);
 771        rxrpc_put_connection(conn);
 772        rxrpc_put_local(local);
 773        return;
 774
 775cant_route_call:
 776        _debug("can't route call");
 777        if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 778            sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 779                if (sp->hdr.seq == cpu_to_be32(1)) {
 780                        _debug("first packet");
 781                        skb_queue_tail(&local->accept_queue, skb);
 782                        rxrpc_queue_work(&local->acceptor);
 783                        rxrpc_put_local(local);
 784                        _leave(" [incoming]");
 785                        return;
 786                }
 787                skb->priority = RX_INVALID_OPERATION;
 788        } else {
 789                skb->priority = RX_CALL_DEAD;
 790        }
 791
 792        _debug("reject");
 793        rxrpc_reject_packet(local, skb);
 794        rxrpc_put_local(local);
 795        _leave(" [no call]");
 796        return;
 797
 798bad_message:
 799        skb->priority = RX_PROTOCOL_ERROR;
 800        rxrpc_reject_packet(local, skb);
 801        rxrpc_put_local(local);
 802        _leave(" [badmsg]");
 803}
 804