linux/net/rxrpc/ar-connection.c
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   1/* RxRPC virtual connection handler
   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/slab.h>
  14#include <linux/net.h>
  15#include <linux/skbuff.h>
  16#include <linux/crypto.h>
  17#include <net/sock.h>
  18#include <net/af_rxrpc.h>
  19#include "ar-internal.h"
  20
  21/*
  22 * Time till a connection expires after last use (in seconds).
  23 */
  24unsigned rxrpc_connection_expiry = 10 * 60;
  25
  26static void rxrpc_connection_reaper(struct work_struct *work);
  27
  28LIST_HEAD(rxrpc_connections);
  29DEFINE_RWLOCK(rxrpc_connection_lock);
  30static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);
  31
  32/*
  33 * allocate a new client connection bundle
  34 */
  35static struct rxrpc_conn_bundle *rxrpc_alloc_bundle(gfp_t gfp)
  36{
  37        struct rxrpc_conn_bundle *bundle;
  38
  39        _enter("");
  40
  41        bundle = kzalloc(sizeof(struct rxrpc_conn_bundle), gfp);
  42        if (bundle) {
  43                INIT_LIST_HEAD(&bundle->unused_conns);
  44                INIT_LIST_HEAD(&bundle->avail_conns);
  45                INIT_LIST_HEAD(&bundle->busy_conns);
  46                init_waitqueue_head(&bundle->chanwait);
  47                atomic_set(&bundle->usage, 1);
  48        }
  49
  50        _leave(" = %p", bundle);
  51        return bundle;
  52}
  53
  54/*
  55 * compare bundle parameters with what we're looking for
  56 * - return -ve, 0 or +ve
  57 */
  58static inline
  59int rxrpc_cmp_bundle(const struct rxrpc_conn_bundle *bundle,
  60                     struct key *key, __be16 service_id)
  61{
  62        return (bundle->service_id - service_id) ?:
  63                ((unsigned long) bundle->key - (unsigned long) key);
  64}
  65
  66/*
  67 * get bundle of client connections that a client socket can make use of
  68 */
  69struct rxrpc_conn_bundle *rxrpc_get_bundle(struct rxrpc_sock *rx,
  70                                           struct rxrpc_transport *trans,
  71                                           struct key *key,
  72                                           __be16 service_id,
  73                                           gfp_t gfp)
  74{
  75        struct rxrpc_conn_bundle *bundle, *candidate;
  76        struct rb_node *p, *parent, **pp;
  77
  78        _enter("%p{%x},%x,%hx,",
  79               rx, key_serial(key), trans->debug_id, ntohs(service_id));
  80
  81        if (rx->trans == trans && rx->bundle) {
  82                atomic_inc(&rx->bundle->usage);
  83                return rx->bundle;
  84        }
  85
  86        /* search the extant bundles first for one that matches the specified
  87         * user ID */
  88        spin_lock(&trans->client_lock);
  89
  90        p = trans->bundles.rb_node;
  91        while (p) {
  92                bundle = rb_entry(p, struct rxrpc_conn_bundle, node);
  93
  94                if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
  95                        p = p->rb_left;
  96                else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
  97                        p = p->rb_right;
  98                else
  99                        goto found_extant_bundle;
 100        }
 101
 102        spin_unlock(&trans->client_lock);
 103
 104        /* not yet present - create a candidate for a new record and then
 105         * redo the search */
 106        candidate = rxrpc_alloc_bundle(gfp);
 107        if (!candidate) {
 108                _leave(" = -ENOMEM");
 109                return ERR_PTR(-ENOMEM);
 110        }
 111
 112        candidate->key = key_get(key);
 113        candidate->service_id = service_id;
 114
 115        spin_lock(&trans->client_lock);
 116
 117        pp = &trans->bundles.rb_node;
 118        parent = NULL;
 119        while (*pp) {
 120                parent = *pp;
 121                bundle = rb_entry(parent, struct rxrpc_conn_bundle, node);
 122
 123                if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
 124                        pp = &(*pp)->rb_left;
 125                else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
 126                        pp = &(*pp)->rb_right;
 127                else
 128                        goto found_extant_second;
 129        }
 130
 131        /* second search also failed; add the new bundle */
 132        bundle = candidate;
 133        candidate = NULL;
 134
 135        rb_link_node(&bundle->node, parent, pp);
 136        rb_insert_color(&bundle->node, &trans->bundles);
 137        spin_unlock(&trans->client_lock);
 138        _net("BUNDLE new on trans %d", trans->debug_id);
 139        if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
 140                atomic_inc(&bundle->usage);
 141                rx->bundle = bundle;
 142        }
 143        _leave(" = %p [new]", bundle);
 144        return bundle;
 145
 146        /* we found the bundle in the list immediately */
 147found_extant_bundle:
 148        atomic_inc(&bundle->usage);
 149        spin_unlock(&trans->client_lock);
 150        _net("BUNDLE old on trans %d", trans->debug_id);
 151        if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
 152                atomic_inc(&bundle->usage);
 153                rx->bundle = bundle;
 154        }
 155        _leave(" = %p [extant %d]", bundle, atomic_read(&bundle->usage));
 156        return bundle;
 157
 158        /* we found the bundle on the second time through the list */
 159found_extant_second:
 160        atomic_inc(&bundle->usage);
 161        spin_unlock(&trans->client_lock);
 162        kfree(candidate);
 163        _net("BUNDLE old2 on trans %d", trans->debug_id);
 164        if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
 165                atomic_inc(&bundle->usage);
 166                rx->bundle = bundle;
 167        }
 168        _leave(" = %p [second %d]", bundle, atomic_read(&bundle->usage));
 169        return bundle;
 170}
 171
 172/*
 173 * release a bundle
 174 */
 175void rxrpc_put_bundle(struct rxrpc_transport *trans,
 176                      struct rxrpc_conn_bundle *bundle)
 177{
 178        _enter("%p,%p{%d}",trans, bundle, atomic_read(&bundle->usage));
 179
 180        if (atomic_dec_and_lock(&bundle->usage, &trans->client_lock)) {
 181                _debug("Destroy bundle");
 182                rb_erase(&bundle->node, &trans->bundles);
 183                spin_unlock(&trans->client_lock);
 184                ASSERT(list_empty(&bundle->unused_conns));
 185                ASSERT(list_empty(&bundle->avail_conns));
 186                ASSERT(list_empty(&bundle->busy_conns));
 187                ASSERTCMP(bundle->num_conns, ==, 0);
 188                key_put(bundle->key);
 189                kfree(bundle);
 190        }
 191
 192        _leave("");
 193}
 194
 195/*
 196 * allocate a new connection
 197 */
 198static struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
 199{
 200        struct rxrpc_connection *conn;
 201
 202        _enter("");
 203
 204        conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
 205        if (conn) {
 206                INIT_WORK(&conn->processor, &rxrpc_process_connection);
 207                INIT_LIST_HEAD(&conn->bundle_link);
 208                conn->calls = RB_ROOT;
 209                skb_queue_head_init(&conn->rx_queue);
 210                rwlock_init(&conn->lock);
 211                spin_lock_init(&conn->state_lock);
 212                atomic_set(&conn->usage, 1);
 213                conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
 214                conn->avail_calls = RXRPC_MAXCALLS;
 215                conn->size_align = 4;
 216                conn->header_size = sizeof(struct rxrpc_header);
 217        }
 218
 219        _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
 220        return conn;
 221}
 222
 223/*
 224 * assign a connection ID to a connection and add it to the transport's
 225 * connection lookup tree
 226 * - called with transport client lock held
 227 */
 228static void rxrpc_assign_connection_id(struct rxrpc_connection *conn)
 229{
 230        struct rxrpc_connection *xconn;
 231        struct rb_node *parent, **p;
 232        __be32 epoch;
 233        u32 real_conn_id;
 234
 235        _enter("");
 236
 237        epoch = conn->epoch;
 238
 239        write_lock_bh(&conn->trans->conn_lock);
 240
 241        conn->trans->conn_idcounter += RXRPC_CID_INC;
 242        if (conn->trans->conn_idcounter < RXRPC_CID_INC)
 243                conn->trans->conn_idcounter = RXRPC_CID_INC;
 244        real_conn_id = conn->trans->conn_idcounter;
 245
 246attempt_insertion:
 247        parent = NULL;
 248        p = &conn->trans->client_conns.rb_node;
 249
 250        while (*p) {
 251                parent = *p;
 252                xconn = rb_entry(parent, struct rxrpc_connection, node);
 253
 254                if (epoch < xconn->epoch)
 255                        p = &(*p)->rb_left;
 256                else if (epoch > xconn->epoch)
 257                        p = &(*p)->rb_right;
 258                else if (real_conn_id < xconn->real_conn_id)
 259                        p = &(*p)->rb_left;
 260                else if (real_conn_id > xconn->real_conn_id)
 261                        p = &(*p)->rb_right;
 262                else
 263                        goto id_exists;
 264        }
 265
 266        /* we've found a suitable hole - arrange for this connection to occupy
 267         * it */
 268        rb_link_node(&conn->node, parent, p);
 269        rb_insert_color(&conn->node, &conn->trans->client_conns);
 270
 271        conn->real_conn_id = real_conn_id;
 272        conn->cid = htonl(real_conn_id);
 273        write_unlock_bh(&conn->trans->conn_lock);
 274        _leave(" [CONNID %x CID %x]", real_conn_id, ntohl(conn->cid));
 275        return;
 276
 277        /* we found a connection with the proposed ID - walk the tree from that
 278         * point looking for the next unused ID */
 279id_exists:
 280        for (;;) {
 281                real_conn_id += RXRPC_CID_INC;
 282                if (real_conn_id < RXRPC_CID_INC) {
 283                        real_conn_id = RXRPC_CID_INC;
 284                        conn->trans->conn_idcounter = real_conn_id;
 285                        goto attempt_insertion;
 286                }
 287
 288                parent = rb_next(parent);
 289                if (!parent)
 290                        goto attempt_insertion;
 291
 292                xconn = rb_entry(parent, struct rxrpc_connection, node);
 293                if (epoch < xconn->epoch ||
 294                    real_conn_id < xconn->real_conn_id)
 295                        goto attempt_insertion;
 296        }
 297}
 298
 299/*
 300 * add a call to a connection's call-by-ID tree
 301 */
 302static void rxrpc_add_call_ID_to_conn(struct rxrpc_connection *conn,
 303                                      struct rxrpc_call *call)
 304{
 305        struct rxrpc_call *xcall;
 306        struct rb_node *parent, **p;
 307        __be32 call_id;
 308
 309        write_lock_bh(&conn->lock);
 310
 311        call_id = call->call_id;
 312        p = &conn->calls.rb_node;
 313        parent = NULL;
 314        while (*p) {
 315                parent = *p;
 316                xcall = rb_entry(parent, struct rxrpc_call, conn_node);
 317
 318                if (call_id < xcall->call_id)
 319                        p = &(*p)->rb_left;
 320                else if (call_id > xcall->call_id)
 321                        p = &(*p)->rb_right;
 322                else
 323                        BUG();
 324        }
 325
 326        rb_link_node(&call->conn_node, parent, p);
 327        rb_insert_color(&call->conn_node, &conn->calls);
 328
 329        write_unlock_bh(&conn->lock);
 330}
 331
 332/*
 333 * connect a call on an exclusive connection
 334 */
 335static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
 336                                   struct rxrpc_transport *trans,
 337                                   __be16 service_id,
 338                                   struct rxrpc_call *call,
 339                                   gfp_t gfp)
 340{
 341        struct rxrpc_connection *conn;
 342        int chan, ret;
 343
 344        _enter("");
 345
 346        conn = rx->conn;
 347        if (!conn) {
 348                /* not yet present - create a candidate for a new connection
 349                 * and then redo the check */
 350                conn = rxrpc_alloc_connection(gfp);
 351                if (!conn) {
 352                        _leave(" = -ENOMEM");
 353                        return -ENOMEM;
 354                }
 355
 356                conn->trans = trans;
 357                conn->bundle = NULL;
 358                conn->service_id = service_id;
 359                conn->epoch = rxrpc_epoch;
 360                conn->in_clientflag = 0;
 361                conn->out_clientflag = RXRPC_CLIENT_INITIATED;
 362                conn->cid = 0;
 363                conn->state = RXRPC_CONN_CLIENT;
 364                conn->avail_calls = RXRPC_MAXCALLS - 1;
 365                conn->security_level = rx->min_sec_level;
 366                conn->key = key_get(rx->key);
 367
 368                ret = rxrpc_init_client_conn_security(conn);
 369                if (ret < 0) {
 370                        key_put(conn->key);
 371                        kfree(conn);
 372                        _leave(" = %d [key]", ret);
 373                        return ret;
 374                }
 375
 376                write_lock_bh(&rxrpc_connection_lock);
 377                list_add_tail(&conn->link, &rxrpc_connections);
 378                write_unlock_bh(&rxrpc_connection_lock);
 379
 380                spin_lock(&trans->client_lock);
 381                atomic_inc(&trans->usage);
 382
 383                _net("CONNECT EXCL new %d on TRANS %d",
 384                     conn->debug_id, conn->trans->debug_id);
 385
 386                rxrpc_assign_connection_id(conn);
 387                rx->conn = conn;
 388        } else {
 389                spin_lock(&trans->client_lock);
 390        }
 391
 392        /* we've got a connection with a free channel and we can now attach the
 393         * call to it
 394         * - we're holding the transport's client lock
 395         * - we're holding a reference on the connection
 396         */
 397        for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
 398                if (!conn->channels[chan])
 399                        goto found_channel;
 400        goto no_free_channels;
 401
 402found_channel:
 403        atomic_inc(&conn->usage);
 404        conn->channels[chan] = call;
 405        call->conn = conn;
 406        call->channel = chan;
 407        call->cid = conn->cid | htonl(chan);
 408        call->call_id = htonl(++conn->call_counter);
 409
 410        _net("CONNECT client on conn %d chan %d as call %x",
 411             conn->debug_id, chan, ntohl(call->call_id));
 412
 413        spin_unlock(&trans->client_lock);
 414
 415        rxrpc_add_call_ID_to_conn(conn, call);
 416        _leave(" = 0");
 417        return 0;
 418
 419no_free_channels:
 420        spin_unlock(&trans->client_lock);
 421        _leave(" = -ENOSR");
 422        return -ENOSR;
 423}
 424
 425/*
 426 * find a connection for a call
 427 * - called in process context with IRQs enabled
 428 */
 429int rxrpc_connect_call(struct rxrpc_sock *rx,
 430                       struct rxrpc_transport *trans,
 431                       struct rxrpc_conn_bundle *bundle,
 432                       struct rxrpc_call *call,
 433                       gfp_t gfp)
 434{
 435        struct rxrpc_connection *conn, *candidate;
 436        int chan, ret;
 437
 438        DECLARE_WAITQUEUE(myself, current);
 439
 440        _enter("%p,%lx,", rx, call->user_call_ID);
 441
 442        if (test_bit(RXRPC_SOCK_EXCLUSIVE_CONN, &rx->flags))
 443                return rxrpc_connect_exclusive(rx, trans, bundle->service_id,
 444                                               call, gfp);
 445
 446        spin_lock(&trans->client_lock);
 447        for (;;) {
 448                /* see if the bundle has a call slot available */
 449                if (!list_empty(&bundle->avail_conns)) {
 450                        _debug("avail");
 451                        conn = list_entry(bundle->avail_conns.next,
 452                                          struct rxrpc_connection,
 453                                          bundle_link);
 454                        if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
 455                                list_del_init(&conn->bundle_link);
 456                                bundle->num_conns--;
 457                                continue;
 458                        }
 459                        if (--conn->avail_calls == 0)
 460                                list_move(&conn->bundle_link,
 461                                          &bundle->busy_conns);
 462                        ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
 463                        ASSERT(conn->channels[0] == NULL ||
 464                               conn->channels[1] == NULL ||
 465                               conn->channels[2] == NULL ||
 466                               conn->channels[3] == NULL);
 467                        atomic_inc(&conn->usage);
 468                        break;
 469                }
 470
 471                if (!list_empty(&bundle->unused_conns)) {
 472                        _debug("unused");
 473                        conn = list_entry(bundle->unused_conns.next,
 474                                          struct rxrpc_connection,
 475                                          bundle_link);
 476                        if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
 477                                list_del_init(&conn->bundle_link);
 478                                bundle->num_conns--;
 479                                continue;
 480                        }
 481                        ASSERTCMP(conn->avail_calls, ==, RXRPC_MAXCALLS);
 482                        conn->avail_calls = RXRPC_MAXCALLS - 1;
 483                        ASSERT(conn->channels[0] == NULL &&
 484                               conn->channels[1] == NULL &&
 485                               conn->channels[2] == NULL &&
 486                               conn->channels[3] == NULL);
 487                        atomic_inc(&conn->usage);
 488                        list_move(&conn->bundle_link, &bundle->avail_conns);
 489                        break;
 490                }
 491
 492                /* need to allocate a new connection */
 493                _debug("get new conn [%d]", bundle->num_conns);
 494
 495                spin_unlock(&trans->client_lock);
 496
 497                if (signal_pending(current))
 498                        goto interrupted;
 499
 500                if (bundle->num_conns >= 20) {
 501                        _debug("too many conns");
 502
 503                        if (!(gfp & __GFP_WAIT)) {
 504                                _leave(" = -EAGAIN");
 505                                return -EAGAIN;
 506                        }
 507
 508                        add_wait_queue(&bundle->chanwait, &myself);
 509                        for (;;) {
 510                                set_current_state(TASK_INTERRUPTIBLE);
 511                                if (bundle->num_conns < 20 ||
 512                                    !list_empty(&bundle->unused_conns) ||
 513                                    !list_empty(&bundle->avail_conns))
 514                                        break;
 515                                if (signal_pending(current))
 516                                        goto interrupted_dequeue;
 517                                schedule();
 518                        }
 519                        remove_wait_queue(&bundle->chanwait, &myself);
 520                        __set_current_state(TASK_RUNNING);
 521                        spin_lock(&trans->client_lock);
 522                        continue;
 523                }
 524
 525                /* not yet present - create a candidate for a new connection and then
 526                 * redo the check */
 527                candidate = rxrpc_alloc_connection(gfp);
 528                if (!candidate) {
 529                        _leave(" = -ENOMEM");
 530                        return -ENOMEM;
 531                }
 532
 533                candidate->trans = trans;
 534                candidate->bundle = bundle;
 535                candidate->service_id = bundle->service_id;
 536                candidate->epoch = rxrpc_epoch;
 537                candidate->in_clientflag = 0;
 538                candidate->out_clientflag = RXRPC_CLIENT_INITIATED;
 539                candidate->cid = 0;
 540                candidate->state = RXRPC_CONN_CLIENT;
 541                candidate->avail_calls = RXRPC_MAXCALLS;
 542                candidate->security_level = rx->min_sec_level;
 543                candidate->key = key_get(bundle->key);
 544
 545                ret = rxrpc_init_client_conn_security(candidate);
 546                if (ret < 0) {
 547                        key_put(candidate->key);
 548                        kfree(candidate);
 549                        _leave(" = %d [key]", ret);
 550                        return ret;
 551                }
 552
 553                write_lock_bh(&rxrpc_connection_lock);
 554                list_add_tail(&candidate->link, &rxrpc_connections);
 555                write_unlock_bh(&rxrpc_connection_lock);
 556
 557                spin_lock(&trans->client_lock);
 558
 559                list_add(&candidate->bundle_link, &bundle->unused_conns);
 560                bundle->num_conns++;
 561                atomic_inc(&bundle->usage);
 562                atomic_inc(&trans->usage);
 563
 564                _net("CONNECT new %d on TRANS %d",
 565                     candidate->debug_id, candidate->trans->debug_id);
 566
 567                rxrpc_assign_connection_id(candidate);
 568                if (candidate->security)
 569                        candidate->security->prime_packet_security(candidate);
 570
 571                /* leave the candidate lurking in zombie mode attached to the
 572                 * bundle until we're ready for it */
 573                rxrpc_put_connection(candidate);
 574                candidate = NULL;
 575        }
 576
 577        /* we've got a connection with a free channel and we can now attach the
 578         * call to it
 579         * - we're holding the transport's client lock
 580         * - we're holding a reference on the connection
 581         * - we're holding a reference on the bundle
 582         */
 583        for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
 584                if (!conn->channels[chan])
 585                        goto found_channel;
 586        ASSERT(conn->channels[0] == NULL ||
 587               conn->channels[1] == NULL ||
 588               conn->channels[2] == NULL ||
 589               conn->channels[3] == NULL);
 590        BUG();
 591
 592found_channel:
 593        conn->channels[chan] = call;
 594        call->conn = conn;
 595        call->channel = chan;
 596        call->cid = conn->cid | htonl(chan);
 597        call->call_id = htonl(++conn->call_counter);
 598
 599        _net("CONNECT client on conn %d chan %d as call %x",
 600             conn->debug_id, chan, ntohl(call->call_id));
 601
 602        ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
 603        spin_unlock(&trans->client_lock);
 604
 605        rxrpc_add_call_ID_to_conn(conn, call);
 606
 607        _leave(" = 0");
 608        return 0;
 609
 610interrupted_dequeue:
 611        remove_wait_queue(&bundle->chanwait, &myself);
 612        __set_current_state(TASK_RUNNING);
 613interrupted:
 614        _leave(" = -ERESTARTSYS");
 615        return -ERESTARTSYS;
 616}
 617
 618/*
 619 * get a record of an incoming connection
 620 */
 621struct rxrpc_connection *
 622rxrpc_incoming_connection(struct rxrpc_transport *trans,
 623                          struct rxrpc_header *hdr,
 624                          gfp_t gfp)
 625{
 626        struct rxrpc_connection *conn, *candidate = NULL;
 627        struct rb_node *p, **pp;
 628        const char *new = "old";
 629        __be32 epoch;
 630        u32 conn_id;
 631
 632        _enter("");
 633
 634        ASSERT(hdr->flags & RXRPC_CLIENT_INITIATED);
 635
 636        epoch = hdr->epoch;
 637        conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
 638
 639        /* search the connection list first */
 640        read_lock_bh(&trans->conn_lock);
 641
 642        p = trans->server_conns.rb_node;
 643        while (p) {
 644                conn = rb_entry(p, struct rxrpc_connection, node);
 645
 646                _debug("maybe %x", conn->real_conn_id);
 647
 648                if (epoch < conn->epoch)
 649                        p = p->rb_left;
 650                else if (epoch > conn->epoch)
 651                        p = p->rb_right;
 652                else if (conn_id < conn->real_conn_id)
 653                        p = p->rb_left;
 654                else if (conn_id > conn->real_conn_id)
 655                        p = p->rb_right;
 656                else
 657                        goto found_extant_connection;
 658        }
 659        read_unlock_bh(&trans->conn_lock);
 660
 661        /* not yet present - create a candidate for a new record and then
 662         * redo the search */
 663        candidate = rxrpc_alloc_connection(gfp);
 664        if (!candidate) {
 665                _leave(" = -ENOMEM");
 666                return ERR_PTR(-ENOMEM);
 667        }
 668
 669        candidate->trans = trans;
 670        candidate->epoch = hdr->epoch;
 671        candidate->cid = hdr->cid & cpu_to_be32(RXRPC_CIDMASK);
 672        candidate->service_id = hdr->serviceId;
 673        candidate->security_ix = hdr->securityIndex;
 674        candidate->in_clientflag = RXRPC_CLIENT_INITIATED;
 675        candidate->out_clientflag = 0;
 676        candidate->real_conn_id = conn_id;
 677        candidate->state = RXRPC_CONN_SERVER;
 678        if (candidate->service_id)
 679                candidate->state = RXRPC_CONN_SERVER_UNSECURED;
 680
 681        write_lock_bh(&trans->conn_lock);
 682
 683        pp = &trans->server_conns.rb_node;
 684        p = NULL;
 685        while (*pp) {
 686                p = *pp;
 687                conn = rb_entry(p, struct rxrpc_connection, node);
 688
 689                if (epoch < conn->epoch)
 690                        pp = &(*pp)->rb_left;
 691                else if (epoch > conn->epoch)
 692                        pp = &(*pp)->rb_right;
 693                else if (conn_id < conn->real_conn_id)
 694                        pp = &(*pp)->rb_left;
 695                else if (conn_id > conn->real_conn_id)
 696                        pp = &(*pp)->rb_right;
 697                else
 698                        goto found_extant_second;
 699        }
 700
 701        /* we can now add the new candidate to the list */
 702        conn = candidate;
 703        candidate = NULL;
 704        rb_link_node(&conn->node, p, pp);
 705        rb_insert_color(&conn->node, &trans->server_conns);
 706        atomic_inc(&conn->trans->usage);
 707
 708        write_unlock_bh(&trans->conn_lock);
 709
 710        write_lock_bh(&rxrpc_connection_lock);
 711        list_add_tail(&conn->link, &rxrpc_connections);
 712        write_unlock_bh(&rxrpc_connection_lock);
 713
 714        new = "new";
 715
 716success:
 717        _net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->real_conn_id);
 718
 719        _leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
 720        return conn;
 721
 722        /* we found the connection in the list immediately */
 723found_extant_connection:
 724        if (hdr->securityIndex != conn->security_ix) {
 725                read_unlock_bh(&trans->conn_lock);
 726                goto security_mismatch;
 727        }
 728        atomic_inc(&conn->usage);
 729        read_unlock_bh(&trans->conn_lock);
 730        goto success;
 731
 732        /* we found the connection on the second time through the list */
 733found_extant_second:
 734        if (hdr->securityIndex != conn->security_ix) {
 735                write_unlock_bh(&trans->conn_lock);
 736                goto security_mismatch;
 737        }
 738        atomic_inc(&conn->usage);
 739        write_unlock_bh(&trans->conn_lock);
 740        kfree(candidate);
 741        goto success;
 742
 743security_mismatch:
 744        kfree(candidate);
 745        _leave(" = -EKEYREJECTED");
 746        return ERR_PTR(-EKEYREJECTED);
 747}
 748
 749/*
 750 * find a connection based on transport and RxRPC connection ID for an incoming
 751 * packet
 752 */
 753struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_transport *trans,
 754                                               struct rxrpc_header *hdr)
 755{
 756        struct rxrpc_connection *conn;
 757        struct rb_node *p;
 758        __be32 epoch;
 759        u32 conn_id;
 760
 761        _enter(",{%x,%x}", ntohl(hdr->cid), hdr->flags);
 762
 763        read_lock_bh(&trans->conn_lock);
 764
 765        conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
 766        epoch = hdr->epoch;
 767
 768        if (hdr->flags & RXRPC_CLIENT_INITIATED)
 769                p = trans->server_conns.rb_node;
 770        else
 771                p = trans->client_conns.rb_node;
 772
 773        while (p) {
 774                conn = rb_entry(p, struct rxrpc_connection, node);
 775
 776                _debug("maybe %x", conn->real_conn_id);
 777
 778                if (epoch < conn->epoch)
 779                        p = p->rb_left;
 780                else if (epoch > conn->epoch)
 781                        p = p->rb_right;
 782                else if (conn_id < conn->real_conn_id)
 783                        p = p->rb_left;
 784                else if (conn_id > conn->real_conn_id)
 785                        p = p->rb_right;
 786                else
 787                        goto found;
 788        }
 789
 790        read_unlock_bh(&trans->conn_lock);
 791        _leave(" = NULL");
 792        return NULL;
 793
 794found:
 795        atomic_inc(&conn->usage);
 796        read_unlock_bh(&trans->conn_lock);
 797        _leave(" = %p", conn);
 798        return conn;
 799}
 800
 801/*
 802 * release a virtual connection
 803 */
 804void rxrpc_put_connection(struct rxrpc_connection *conn)
 805{
 806        _enter("%p{u=%d,d=%d}",
 807               conn, atomic_read(&conn->usage), conn->debug_id);
 808
 809        ASSERTCMP(atomic_read(&conn->usage), >, 0);
 810
 811        conn->put_time = get_seconds();
 812        if (atomic_dec_and_test(&conn->usage)) {
 813                _debug("zombie");
 814                rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 815        }
 816
 817        _leave("");
 818}
 819
 820/*
 821 * destroy a virtual connection
 822 */
 823static void rxrpc_destroy_connection(struct rxrpc_connection *conn)
 824{
 825        _enter("%p{%d}", conn, atomic_read(&conn->usage));
 826
 827        ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 828
 829        _net("DESTROY CONN %d", conn->debug_id);
 830
 831        if (conn->bundle)
 832                rxrpc_put_bundle(conn->trans, conn->bundle);
 833
 834        ASSERT(RB_EMPTY_ROOT(&conn->calls));
 835        rxrpc_purge_queue(&conn->rx_queue);
 836
 837        rxrpc_clear_conn_security(conn);
 838        rxrpc_put_transport(conn->trans);
 839        kfree(conn);
 840        _leave("");
 841}
 842
 843/*
 844 * reap dead connections
 845 */
 846static void rxrpc_connection_reaper(struct work_struct *work)
 847{
 848        struct rxrpc_connection *conn, *_p;
 849        unsigned long now, earliest, reap_time;
 850
 851        LIST_HEAD(graveyard);
 852
 853        _enter("");
 854
 855        now = get_seconds();
 856        earliest = ULONG_MAX;
 857
 858        write_lock_bh(&rxrpc_connection_lock);
 859        list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
 860                _debug("reap CONN %d { u=%d,t=%ld }",
 861                       conn->debug_id, atomic_read(&conn->usage),
 862                       (long) now - (long) conn->put_time);
 863
 864                if (likely(atomic_read(&conn->usage) > 0))
 865                        continue;
 866
 867                spin_lock(&conn->trans->client_lock);
 868                write_lock(&conn->trans->conn_lock);
 869                reap_time = conn->put_time + rxrpc_connection_expiry;
 870
 871                if (atomic_read(&conn->usage) > 0) {
 872                        ;
 873                } else if (reap_time <= now) {
 874                        list_move_tail(&conn->link, &graveyard);
 875                        if (conn->out_clientflag)
 876                                rb_erase(&conn->node,
 877                                         &conn->trans->client_conns);
 878                        else
 879                                rb_erase(&conn->node,
 880                                         &conn->trans->server_conns);
 881                        if (conn->bundle) {
 882                                list_del_init(&conn->bundle_link);
 883                                conn->bundle->num_conns--;
 884                        }
 885
 886                } else if (reap_time < earliest) {
 887                        earliest = reap_time;
 888                }
 889
 890                write_unlock(&conn->trans->conn_lock);
 891                spin_unlock(&conn->trans->client_lock);
 892        }
 893        write_unlock_bh(&rxrpc_connection_lock);
 894
 895        if (earliest != ULONG_MAX) {
 896                _debug("reschedule reaper %ld", (long) earliest - now);
 897                ASSERTCMP(earliest, >, now);
 898                rxrpc_queue_delayed_work(&rxrpc_connection_reap,
 899                                         (earliest - now) * HZ);
 900        }
 901
 902        /* then destroy all those pulled out */
 903        while (!list_empty(&graveyard)) {
 904                conn = list_entry(graveyard.next, struct rxrpc_connection,
 905                                  link);
 906                list_del_init(&conn->link);
 907
 908                ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 909                rxrpc_destroy_connection(conn);
 910        }
 911
 912        _leave("");
 913}
 914
 915/*
 916 * preemptively destroy all the connection records rather than waiting for them
 917 * to time out
 918 */
 919void __exit rxrpc_destroy_all_connections(void)
 920{
 921        _enter("");
 922
 923        rxrpc_connection_expiry = 0;
 924        cancel_delayed_work(&rxrpc_connection_reap);
 925        rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 926
 927        _leave("");
 928}
 929