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 int) 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_ACKALL:
 427        case RXRPC_PACKET_TYPE_ACK:
 428                /* ACK processing is done in process context */
 429                read_lock_bh(&call->state_lock);
 430                if (call->state < RXRPC_CALL_DEAD) {
 431                        skb_queue_tail(&call->rx_queue, skb);
 432                        rxrpc_queue_call(call);
 433                        skb = NULL;
 434                }
 435                read_unlock_bh(&call->state_lock);
 436                goto free_packet;
 437        }
 438
 439protocol_error:
 440        _debug("protocol error");
 441        write_lock_bh(&call->state_lock);
 442protocol_error_locked:
 443        if (call->state <= RXRPC_CALL_COMPLETE) {
 444                call->state = RXRPC_CALL_LOCALLY_ABORTED;
 445                call->abort_code = RX_PROTOCOL_ERROR;
 446                set_bit(RXRPC_CALL_ABORT, &call->events);
 447                rxrpc_queue_call(call);
 448        }
 449free_packet_unlock:
 450        write_unlock_bh(&call->state_lock);
 451free_packet:
 452        rxrpc_free_skb(skb);
 453done:
 454        _leave("");
 455}
 456
 457/*
 458 * split up a jumbo data packet
 459 */
 460static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
 461                                       struct sk_buff *jumbo)
 462{
 463        struct rxrpc_jumbo_header jhdr;
 464        struct rxrpc_skb_priv *sp;
 465        struct sk_buff *part;
 466
 467        _enter(",{%u,%u}", jumbo->data_len, jumbo->len);
 468
 469        sp = rxrpc_skb(jumbo);
 470
 471        do {
 472                sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
 473
 474                /* make a clone to represent the first subpacket in what's left
 475                 * of the jumbo packet */
 476                part = skb_clone(jumbo, GFP_ATOMIC);
 477                if (!part) {
 478                        /* simply ditch the tail in the event of ENOMEM */
 479                        pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
 480                        break;
 481                }
 482                rxrpc_new_skb(part);
 483
 484                pskb_trim(part, RXRPC_JUMBO_DATALEN);
 485
 486                if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
 487                        goto protocol_error;
 488
 489                if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
 490                        goto protocol_error;
 491                if (!pskb_pull(jumbo, sizeof(jhdr)))
 492                        BUG();
 493
 494                sp->hdr.seq     = htonl(ntohl(sp->hdr.seq) + 1);
 495                sp->hdr.serial  = htonl(ntohl(sp->hdr.serial) + 1);
 496                sp->hdr.flags   = jhdr.flags;
 497                sp->hdr._rsvd   = jhdr._rsvd;
 498
 499                _proto("Rx DATA Jumbo %%%u", ntohl(sp->hdr.serial) - 1);
 500
 501                rxrpc_fast_process_packet(call, part);
 502                part = NULL;
 503
 504        } while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
 505
 506        rxrpc_fast_process_packet(call, jumbo);
 507        _leave("");
 508        return;
 509
 510protocol_error:
 511        _debug("protocol error");
 512        rxrpc_free_skb(part);
 513        rxrpc_free_skb(jumbo);
 514        write_lock_bh(&call->state_lock);
 515        if (call->state <= RXRPC_CALL_COMPLETE) {
 516                call->state = RXRPC_CALL_LOCALLY_ABORTED;
 517                call->abort_code = RX_PROTOCOL_ERROR;
 518                set_bit(RXRPC_CALL_ABORT, &call->events);
 519                rxrpc_queue_call(call);
 520        }
 521        write_unlock_bh(&call->state_lock);
 522        _leave("");
 523}
 524
 525/*
 526 * post an incoming packet to the appropriate call/socket to deal with
 527 * - must get rid of the sk_buff, either by freeing it or by queuing it
 528 */
 529static void rxrpc_post_packet_to_call(struct rxrpc_connection *conn,
 530                                      struct sk_buff *skb)
 531{
 532        struct rxrpc_skb_priv *sp;
 533        struct rxrpc_call *call;
 534        struct rb_node *p;
 535        __be32 call_id;
 536
 537        _enter("%p,%p", conn, skb);
 538
 539        read_lock_bh(&conn->lock);
 540
 541        sp = rxrpc_skb(skb);
 542
 543        /* look at extant calls by channel number first */
 544        call = conn->channels[ntohl(sp->hdr.cid) & RXRPC_CHANNELMASK];
 545        if (!call || call->call_id != sp->hdr.callNumber)
 546                goto call_not_extant;
 547
 548        _debug("extant call [%d]", call->state);
 549        ASSERTCMP(call->conn, ==, conn);
 550
 551        read_lock(&call->state_lock);
 552        switch (call->state) {
 553        case RXRPC_CALL_LOCALLY_ABORTED:
 554                if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
 555                        rxrpc_queue_call(call);
 556        case RXRPC_CALL_REMOTELY_ABORTED:
 557        case RXRPC_CALL_NETWORK_ERROR:
 558        case RXRPC_CALL_DEAD:
 559                goto free_unlock;
 560        default:
 561                break;
 562        }
 563
 564        read_unlock(&call->state_lock);
 565        rxrpc_get_call(call);
 566        read_unlock_bh(&conn->lock);
 567
 568        if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 569            sp->hdr.flags & RXRPC_JUMBO_PACKET)
 570                rxrpc_process_jumbo_packet(call, skb);
 571        else
 572                rxrpc_fast_process_packet(call, skb);
 573
 574        rxrpc_put_call(call);
 575        goto done;
 576
 577call_not_extant:
 578        /* search the completed calls in case what we're dealing with is
 579         * there */
 580        _debug("call not extant");
 581
 582        call_id = sp->hdr.callNumber;
 583        p = conn->calls.rb_node;
 584        while (p) {
 585                call = rb_entry(p, struct rxrpc_call, conn_node);
 586
 587                if (call_id < call->call_id)
 588                        p = p->rb_left;
 589                else if (call_id > call->call_id)
 590                        p = p->rb_right;
 591                else
 592                        goto found_completed_call;
 593        }
 594
 595dead_call:
 596        /* it's a either a really old call that we no longer remember or its a
 597         * new incoming call */
 598        read_unlock_bh(&conn->lock);
 599
 600        if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 601            sp->hdr.seq == cpu_to_be32(1)) {
 602                _debug("incoming call");
 603                skb_queue_tail(&conn->trans->local->accept_queue, skb);
 604                rxrpc_queue_work(&conn->trans->local->acceptor);
 605                goto done;
 606        }
 607
 608        _debug("dead call");
 609        skb->priority = RX_CALL_DEAD;
 610        rxrpc_reject_packet(conn->trans->local, skb);
 611        goto done;
 612
 613        /* resend last packet of a completed call
 614         * - client calls may have been aborted or ACK'd
 615         * - server calls may have been aborted
 616         */
 617found_completed_call:
 618        _debug("completed call");
 619
 620        if (atomic_read(&call->usage) == 0)
 621                goto dead_call;
 622
 623        /* synchronise any state changes */
 624        read_lock(&call->state_lock);
 625        ASSERTIFCMP(call->state != RXRPC_CALL_CLIENT_FINAL_ACK,
 626                    call->state, >=, RXRPC_CALL_COMPLETE);
 627
 628        if (call->state == RXRPC_CALL_LOCALLY_ABORTED ||
 629            call->state == RXRPC_CALL_REMOTELY_ABORTED ||
 630            call->state == RXRPC_CALL_DEAD) {
 631                read_unlock(&call->state_lock);
 632                goto dead_call;
 633        }
 634
 635        if (call->conn->in_clientflag) {
 636                read_unlock(&call->state_lock);
 637                goto dead_call; /* complete server call */
 638        }
 639
 640        _debug("final ack again");
 641        rxrpc_get_call(call);
 642        set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
 643        rxrpc_queue_call(call);
 644
 645free_unlock:
 646        read_unlock(&call->state_lock);
 647        read_unlock_bh(&conn->lock);
 648        rxrpc_free_skb(skb);
 649done:
 650        _leave("");
 651}
 652
 653/*
 654 * post connection-level events to the connection
 655 * - this includes challenges, responses and some aborts
 656 */
 657static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
 658                                      struct sk_buff *skb)
 659{
 660        _enter("%p,%p", conn, skb);
 661
 662        atomic_inc(&conn->usage);
 663        skb_queue_tail(&conn->rx_queue, skb);
 664        rxrpc_queue_conn(conn);
 665}
 666
 667/*
 668 * handle data received on the local endpoint
 669 * - may be called in interrupt context
 670 */
 671void rxrpc_data_ready(struct sock *sk, int count)
 672{
 673        struct rxrpc_connection *conn;
 674        struct rxrpc_transport *trans;
 675        struct rxrpc_skb_priv *sp;
 676        struct rxrpc_local *local;
 677        struct rxrpc_peer *peer;
 678        struct sk_buff *skb;
 679        int ret;
 680
 681        _enter("%p, %d", sk, count);
 682
 683        ASSERT(!irqs_disabled());
 684
 685        read_lock_bh(&rxrpc_local_lock);
 686        local = sk->sk_user_data;
 687        if (local && atomic_read(&local->usage) > 0)
 688                rxrpc_get_local(local);
 689        else
 690                local = NULL;
 691        read_unlock_bh(&rxrpc_local_lock);
 692        if (!local) {
 693                _leave(" [local dead]");
 694                return;
 695        }
 696
 697        skb = skb_recv_datagram(sk, 0, 1, &ret);
 698        if (!skb) {
 699                rxrpc_put_local(local);
 700                if (ret == -EAGAIN)
 701                        return;
 702                _debug("UDP socket error %d", ret);
 703                return;
 704        }
 705
 706        rxrpc_new_skb(skb);
 707
 708        _net("recv skb %p", skb);
 709
 710        /* we'll probably need to checksum it (didn't call sock_recvmsg) */
 711        if (skb_checksum_complete(skb)) {
 712                rxrpc_free_skb(skb);
 713                rxrpc_put_local(local);
 714                UDP_INC_STATS_BH(&init_net, UDP_MIB_INERRORS, 0);
 715                _leave(" [CSUM failed]");
 716                return;
 717        }
 718
 719        UDP_INC_STATS_BH(&init_net, UDP_MIB_INDATAGRAMS, 0);
 720
 721        /* the socket buffer we have is owned by UDP, with UDP's data all over
 722         * it, but we really want our own */
 723        skb_orphan(skb);
 724        sp = rxrpc_skb(skb);
 725        memset(sp, 0, sizeof(*sp));
 726
 727        _net("Rx UDP packet from %08x:%04hu",
 728             ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
 729
 730        /* dig out the RxRPC connection details */
 731        if (skb_copy_bits(skb, sizeof(struct udphdr), &sp->hdr,
 732                          sizeof(sp->hdr)) < 0)
 733                goto bad_message;
 734        if (!pskb_pull(skb, sizeof(struct udphdr) + sizeof(sp->hdr)))
 735                BUG();
 736
 737        _net("Rx RxRPC %s ep=%x call=%x:%x",
 738             sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
 739             ntohl(sp->hdr.epoch),
 740             ntohl(sp->hdr.cid),
 741             ntohl(sp->hdr.callNumber));
 742
 743        if (sp->hdr.type == 0 || sp->hdr.type >= RXRPC_N_PACKET_TYPES) {
 744                _proto("Rx Bad Packet Type %u", sp->hdr.type);
 745                goto bad_message;
 746        }
 747
 748        if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
 749            (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
 750                goto bad_message;
 751
 752        peer = rxrpc_find_peer(local, ip_hdr(skb)->saddr, udp_hdr(skb)->source);
 753        if (IS_ERR(peer))
 754                goto cant_route_call;
 755
 756        trans = rxrpc_find_transport(local, peer);
 757        rxrpc_put_peer(peer);
 758        if (!trans)
 759                goto cant_route_call;
 760
 761        conn = rxrpc_find_connection(trans, &sp->hdr);
 762        rxrpc_put_transport(trans);
 763        if (!conn)
 764                goto cant_route_call;
 765
 766        _debug("CONN %p {%d}", conn, conn->debug_id);
 767
 768        if (sp->hdr.callNumber == 0)
 769                rxrpc_post_packet_to_conn(conn, skb);
 770        else
 771                rxrpc_post_packet_to_call(conn, skb);
 772        rxrpc_put_connection(conn);
 773        rxrpc_put_local(local);
 774        return;
 775
 776cant_route_call:
 777        _debug("can't route call");
 778        if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
 779            sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
 780                if (sp->hdr.seq == cpu_to_be32(1)) {
 781                        _debug("first packet");
 782                        skb_queue_tail(&local->accept_queue, skb);
 783                        rxrpc_queue_work(&local->acceptor);
 784                        rxrpc_put_local(local);
 785                        _leave(" [incoming]");
 786                        return;
 787                }
 788                skb->priority = RX_INVALID_OPERATION;
 789        } else {
 790                skb->priority = RX_CALL_DEAD;
 791        }
 792
 793        _debug("reject");
 794        rxrpc_reject_packet(local, skb);
 795        rxrpc_put_local(local);
 796        _leave(" [no call]");
 797        return;
 798
 799bad_message:
 800        skb->priority = RX_PROTOCOL_ERROR;
 801        rxrpc_reject_packet(local, skb);
 802        rxrpc_put_local(local);
 803        _leave(" [badmsg]");
 804}
 805
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