net/rxrpc/ar-connection.c

   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/net.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/crypto.h>
  16 #include <net/sock.h>
  17 #include <net/af_rxrpc.h>
  18 #include "ar-internal.h"
  19
  20 static void rxrpc_connection_reaper(struct work_struct *work);
  21
  22 LIST_HEAD(rxrpc_connections);
  23 DEFINE_RWLOCK(rxrpc_connection_lock);
  24 static unsigned long rxrpc_connection_timeout = 10 * 60;
  25 static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);
  26
  27 /*
  28  * allocate a new client connection bundle
  29  */
  30 static struct rxrpc_conn_bundle *rxrpc_alloc_bundle(gfp_t gfp)
  31 {
  32         struct rxrpc_conn_bundle *bundle;
  33
  34         _enter("");
  35
  36         bundle = kzalloc(sizeof(struct rxrpc_conn_bundle), gfp);
  37         if (bundle) {
  38                 INIT_LIST_HEAD(&bundle->unused_conns);
  39                 INIT_LIST_HEAD(&bundle->avail_conns);
  40                 INIT_LIST_HEAD(&bundle->busy_conns);
  41                 init_waitqueue_head(&bundle->chanwait);
  42                 atomic_set(&bundle->usage, 1);
  43         }
  44
  45         _leave(" = %p", bundle);
  46         return bundle;
  47 }
  48
  49 /*
  50  * compare bundle parameters with what we're looking for
  51  * - return -ve, 0 or +ve
  52  */
  53 static inline
  54 int rxrpc_cmp_bundle(const struct rxrpc_conn_bundle *bundle,
  55                      struct key *key, __be16 service_id)
  56 {
  57         return (bundle->service_id - service_id) ?:
  58                 ((unsigned long) bundle->key - (unsigned long) key);
  59 }
  60
  61 /*
  62  * get bundle of client connections that a client socket can make use of
  63  */
  64 struct rxrpc_conn_bundle *rxrpc_get_bundle(struct rxrpc_sock *rx,
  65                                            struct rxrpc_transport *trans,
  66                                            struct key *key,
  67                                            __be16 service_id,
  68                                            gfp_t gfp)
  69 {
  70         struct rxrpc_conn_bundle *bundle, *candidate;
  71         struct rb_node *p, *parent, **pp;
  72
  73         _enter("%p{%x},%x,%hx,",
  74                rx, key_serial(key), trans->debug_id, ntohl(service_id));
  75
  76         if (rx->trans == trans && rx->bundle) {
  77                 atomic_inc(&rx->bundle->usage);
  78                 return rx->bundle;
  79         }
  80
  81         /* search the extant bundles first for one that matches the specified
  82          * user ID */
  83         spin_lock(&trans->client_lock);
  84
  85         p = trans->bundles.rb_node;
  86         while (p) {
  87                 bundle = rb_entry(p, struct rxrpc_conn_bundle, node);
  88
  89                 if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
  90                         p = p->rb_left;
  91                 else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
  92                         p = p->rb_right;
  93                 else
  94                         goto found_extant_bundle;
  95         }
  96
  97         spin_unlock(&trans->client_lock);
  98
  99         /* not yet present - create a candidate for a new record and then
 100          * redo the search */
 101         candidate = rxrpc_alloc_bundle(gfp);
 102         if (!candidate) {
 103                 _leave(" = -ENOMEM");
 104                 return ERR_PTR(-ENOMEM);
 105         }
 106
 107         candidate->key = key_get(key);
 108         candidate->service_id = service_id;
 109
 110         spin_lock(&trans->client_lock);
 111
 112         pp = &trans->bundles.rb_node;
 113         parent = NULL;
 114         while (*pp) {
 115                 parent = *pp;
 116                 bundle = rb_entry(parent, struct rxrpc_conn_bundle, node);
 117
 118                 if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
 119                         pp = &(*pp)->rb_left;
 120                 else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
 121                         pp = &(*pp)->rb_right;
 122                 else
 123                         goto found_extant_second;
 124         }
 125
 126         /* second search also failed; add the new bundle */
 127         bundle = candidate;
 128         candidate = NULL;
 129
 130         rb_link_node(&bundle->node, parent, pp);
 131         rb_insert_color(&bundle->node, &trans->bundles);
 132         spin_unlock(&trans->client_lock);
 133         _net("BUNDLE new on trans %d", trans->debug_id);
 134         if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
 135                 atomic_inc(&bundle->usage);
 136                 rx->bundle = bundle;
 137         }
 138         _leave(" = %p [new]", bundle);
 139         return bundle;
 140
 141         /* we found the bundle in the list immediately */
 142 found_extant_bundle:
 143         atomic_inc(&bundle->usage);
 144         spin_unlock(&trans->client_lock);
 145         _net("BUNDLE old on trans %d", trans->debug_id);
 146         if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
 147                 atomic_inc(&bundle->usage);
 148                 rx->bundle = bundle;
 149         }
 150         _leave(" = %p [extant %d]", bundle, atomic_read(&bundle->usage));
 151         return bundle;
 152
 153         /* we found the bundle on the second time through the list */
 154 found_extant_second:
 155         atomic_inc(&bundle->usage);
 156         spin_unlock(&trans->client_lock);
 157         kfree(candidate);
 158         _net("BUNDLE old2 on trans %d", trans->debug_id);
 159         if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
 160                 atomic_inc(&bundle->usage);
 161                 rx->bundle = bundle;
 162         }
 163         _leave(" = %p [second %d]", bundle, atomic_read(&bundle->usage));
 164         return bundle;
 165 }
 166
 167 /*
 168  * release a bundle
 169  */
 170 void rxrpc_put_bundle(struct rxrpc_transport *trans,
 171                       struct rxrpc_conn_bundle *bundle)
 172 {
 173         _enter("%p,%p{%d}",trans, bundle, atomic_read(&bundle->usage));
 174
 175         if (atomic_dec_and_lock(&bundle->usage, &trans->client_lock)) {
 176                 _debug("Destroy bundle");
 177                 rb_erase(&bundle->node, &trans->bundles);
 178                 spin_unlock(&trans->client_lock);
 179                 ASSERT(list_empty(&bundle->unused_conns));
 180                 ASSERT(list_empty(&bundle->avail_conns));
 181                 ASSERT(list_empty(&bundle->busy_conns));
 182                 ASSERTCMP(bundle->num_conns, ==, 0);
 183                 key_put(bundle->key);
 184                 kfree(bundle);
 185         }
 186
 187         _leave("");
 188 }
 189
 190 /*
 191  * allocate a new connection
 192  */
 193 static struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
 194 {
 195         struct rxrpc_connection *conn;
 196
 197         _enter("");
 198
 199         conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
 200         if (conn) {
 201                 INIT_WORK(&conn->processor, &rxrpc_process_connection);
 202                 INIT_LIST_HEAD(&conn->bundle_link);
 203                 conn->calls = RB_ROOT;
 204                 skb_queue_head_init(&conn->rx_queue);
 205                 rwlock_init(&conn->lock);
 206                 spin_lock_init(&conn->state_lock);
 207                 atomic_set(&conn->usage, 1);
 208                 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
 209                 conn->avail_calls = RXRPC_MAXCALLS;
 210                 conn->size_align = 4;
 211                 conn->header_size = sizeof(struct rxrpc_header);
 212         }
 213
 214         _leave(" = %p{%d}", conn, conn->debug_id);
 215         return conn;
 216 }
 217
 218 /*
 219  * assign a connection ID to a connection and add it to the transport's
 220  * connection lookup tree
 221  * - called with transport client lock held
 222  */
 223 static void rxrpc_assign_connection_id(struct rxrpc_connection *conn)
 224 {
 225         struct rxrpc_connection *xconn;
 226         struct rb_node *parent, **p;
 227         __be32 epoch;
 228         u32 real_conn_id;
 229
 230         _enter("");
 231
 232         epoch = conn->epoch;
 233
 234         write_lock_bh(&conn->trans->conn_lock);
 235
 236         conn->trans->conn_idcounter += RXRPC_CID_INC;
 237         if (conn->trans->conn_idcounter < RXRPC_CID_INC)
 238                 conn->trans->conn_idcounter = RXRPC_CID_INC;
 239         real_conn_id = conn->trans->conn_idcounter;
 240
 241 attempt_insertion:
 242         parent = NULL;
 243         p = &conn->trans->client_conns.rb_node;
 244
 245         while (*p) {
 246                 parent = *p;
 247                 xconn = rb_entry(parent, struct rxrpc_connection, node);
 248
 249                 if (epoch < xconn->epoch)
 250                         p = &(*p)->rb_left;
 251                 else if (epoch > xconn->epoch)
 252                         p = &(*p)->rb_right;
 253                 else if (real_conn_id < xconn->real_conn_id)
 254                         p = &(*p)->rb_left;
 255                 else if (real_conn_id > xconn->real_conn_id)
 256                         p = &(*p)->rb_right;
 257                 else
 258                         goto id_exists;
 259         }
 260
 261         /* we've found a suitable hole - arrange for this connection to occupy
 262          * it */
 263         rb_link_node(&conn->node, parent, p);
 264         rb_insert_color(&conn->node, &conn->trans->client_conns);
 265
 266         conn->real_conn_id = real_conn_id;
 267         conn->cid = htonl(real_conn_id);
 268         write_unlock_bh(&conn->trans->conn_lock);
 269         _leave(" [CONNID %x CID %x]", real_conn_id, ntohl(conn->cid));
 270         return;
 271
 272         /* we found a connection with the proposed ID - walk the tree from that
 273          * point looking for the next unused ID */
 274 id_exists:
 275         for (;;) {
 276                 real_conn_id += RXRPC_CID_INC;
 277                 if (real_conn_id < RXRPC_CID_INC) {
 278                         real_conn_id = RXRPC_CID_INC;
 279                         conn->trans->conn_idcounter = real_conn_id;
 280                         goto attempt_insertion;
 281                 }
 282
 283                 parent = rb_next(parent);
 284                 if (!parent)
 285                         goto attempt_insertion;
 286
 287                 xconn = rb_entry(parent, struct rxrpc_connection, node);
 288                 if (epoch < xconn->epoch ||
 289                     real_conn_id < xconn->real_conn_id)
 290                         goto attempt_insertion;
 291         }
 292 }
 293
 294 /*
 295  * add a call to a connection's call-by-ID tree
 296  */
 297 static void rxrpc_add_call_ID_to_conn(struct rxrpc_connection *conn,
 298                                       struct rxrpc_call *call)
 299 {
 300         struct rxrpc_call *xcall;
 301         struct rb_node *parent, **p;
 302         __be32 call_id;
 303
 304         write_lock_bh(&conn->lock);
 305
 306         call_id = call->call_id;
 307         p = &conn->calls.rb_node;
 308         parent = NULL;
 309         while (*p) {
 310                 parent = *p;
 311                 xcall = rb_entry(parent, struct rxrpc_call, conn_node);
 312
 313                 if (call_id < xcall->call_id)
 314                         p = &(*p)->rb_left;
 315                 else if (call_id > xcall->call_id)
 316                         p = &(*p)->rb_right;
 317                 else
 318                         BUG();
 319         }
 320
 321         rb_link_node(&call->conn_node, parent, p);
 322         rb_insert_color(&call->conn_node, &conn->calls);
 323
 324         write_unlock_bh(&conn->lock);
 325 }
 326
 327 /*
 328  * connect a call on an exclusive connection
 329  */
 330 static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
 331                                    struct rxrpc_transport *trans,
 332                                    __be16 service_id,
 333                                    struct rxrpc_call *call,
 334                                    gfp_t gfp)
 335 {
 336         struct rxrpc_connection *conn;
 337         int chan, ret;
 338
 339         _enter("");
 340
 341         conn = rx->conn;
 342         if (!conn) {
 343                 /* not yet present - create a candidate for a new connection
 344                  * and then redo the check */
 345                 conn = rxrpc_alloc_connection(gfp);
 346                 if (IS_ERR(conn)) {
 347                         _leave(" = %ld", PTR_ERR(conn));
 348                         return PTR_ERR(conn);
 349                 }
 350
 351                 conn->trans = trans;
 352                 conn->bundle = NULL;
 353                 conn->service_id = service_id;
 354                 conn->epoch = rxrpc_epoch;
 355                 conn->in_clientflag = 0;
 356                 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
 357                 conn->cid = 0;
 358                 conn->state = RXRPC_CONN_CLIENT;
 359                 conn->avail_calls = RXRPC_MAXCALLS - 1;
 360                 conn->security_level = rx->min_sec_level;
 361                 conn->key = key_get(rx->key);
 362
 363                 ret = rxrpc_init_client_conn_security(conn);
 364                 if (ret < 0) {
 365                         key_put(conn->key);
 366                         kfree(conn);
 367                         _leave(" = %d [key]", ret);
 368                         return ret;
 369                 }
 370
 371                 write_lock_bh(&rxrpc_connection_lock);
 372                 list_add_tail(&conn->link, &rxrpc_connections);
 373                 write_unlock_bh(&rxrpc_connection_lock);
 374
 375                 spin_lock(&trans->client_lock);
 376                 atomic_inc(&trans->usage);
 377
 378                 _net("CONNECT EXCL new %d on TRANS %d",
 379                      conn->debug_id, conn->trans->debug_id);
 380
 381                 rxrpc_assign_connection_id(conn);
 382                 rx->conn = conn;
 383         }
 384
 385         /* we've got a connection with a free channel and we can now attach the
 386          * call to it
 387          * - we're holding the transport's client lock
 388          * - we're holding a reference on the connection
 389          */
 390         for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
 391                 if (!conn->channels[chan])
 392                         goto found_channel;
 393         goto no_free_channels;
 394
 395 found_channel:
 396         atomic_inc(&conn->usage);
 397         conn->channels[chan] = call;
 398         call->conn = conn;
 399         call->channel = chan;
 400         call->cid = conn->cid | htonl(chan);
 401         call->call_id = htonl(++conn->call_counter);
 402
 403         _net("CONNECT client on conn %d chan %d as call %x",
 404              conn->debug_id, chan, ntohl(call->call_id));
 405
 406         spin_unlock(&trans->client_lock);
 407
 408         rxrpc_add_call_ID_to_conn(conn, call);
 409         _leave(" = 0");
 410         return 0;
 411
 412 no_free_channels:
 413         spin_unlock(&trans->client_lock);
 414         _leave(" = -ENOSR");
 415         return -ENOSR;
 416 }
 417
 418 /*
 419  * find a connection for a call
 420  * - called in process context with IRQs enabled
 421  */
 422 int rxrpc_connect_call(struct rxrpc_sock *rx,
 423                        struct rxrpc_transport *trans,
 424                        struct rxrpc_conn_bundle *bundle,
 425                        struct rxrpc_call *call,
 426                        gfp_t gfp)
 427 {
 428         struct rxrpc_connection *conn, *candidate;
 429         int chan, ret;
 430
 431         DECLARE_WAITQUEUE(myself, current);
 432
 433         _enter("%p,%lx,", rx, call->user_call_ID);
 434
 435         if (test_bit(RXRPC_SOCK_EXCLUSIVE_CONN, &rx->flags))
 436                 return rxrpc_connect_exclusive(rx, trans, bundle->service_id,
 437                                                call, gfp);
 438
 439         spin_lock(&trans->client_lock);
 440         for (;;) {
 441                 /* see if the bundle has a call slot available */
 442                 if (!list_empty(&bundle->avail_conns)) {
 443                         _debug("avail");
 444                         conn = list_entry(bundle->avail_conns.next,
 445                                           struct rxrpc_connection,
 446                                           bundle_link);
 447                         if (--conn->avail_calls == 0)
 448                                 list_move(&conn->bundle_link,
 449                                           &bundle->busy_conns);
 450                         ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
 451                         ASSERT(conn->channels[0] == NULL ||
 452                                conn->channels[1] == NULL ||
 453                                conn->channels[2] == NULL ||
 454                                conn->channels[3] == NULL);
 455                         atomic_inc(&conn->usage);
 456                         break;
 457                 }
 458
 459                 if (!list_empty(&bundle->unused_conns)) {
 460                         _debug("unused");
 461                         conn = list_entry(bundle->unused_conns.next,
 462                                           struct rxrpc_connection,
 463                                           bundle_link);
 464                         ASSERTCMP(conn->avail_calls, ==, RXRPC_MAXCALLS);
 465                         conn->avail_calls = RXRPC_MAXCALLS - 1;
 466                         ASSERT(conn->channels[0] == NULL &&
 467                                conn->channels[1] == NULL &&
 468                                conn->channels[2] == NULL &&
 469                                conn->channels[3] == NULL);
 470                         atomic_inc(&conn->usage);
 471                         list_move(&conn->bundle_link, &bundle->avail_conns);
 472                         break;
 473                 }
 474
 475                 /* need to allocate a new connection */
 476                 _debug("get new conn [%d]", bundle->num_conns);
 477
 478                 spin_unlock(&trans->client_lock);
 479
 480                 if (signal_pending(current))
 481                         goto interrupted;
 482
 483                 if (bundle->num_conns >= 20) {
 484                         _debug("too many conns");
 485
 486                         if (!(gfp & __GFP_WAIT)) {
 487                                 _leave(" = -EAGAIN");
 488                                 return -EAGAIN;
 489                         }
 490
 491                         add_wait_queue(&bundle->chanwait, &myself);
 492                         for (;;) {
 493                                 set_current_state(TASK_INTERRUPTIBLE);
 494                                 if (bundle->num_conns < 20 ||
 495                                     !list_empty(&bundle->unused_conns) ||
 496                                     !list_empty(&bundle->avail_conns))
 497                                         break;
 498                                 if (signal_pending(current))
 499                                         goto interrupted_dequeue;
 500                                 schedule();
 501                         }
 502                         remove_wait_queue(&bundle->chanwait, &myself);
 503                         __set_current_state(TASK_RUNNING);
 504                         spin_lock(&trans->client_lock);
 505                         continue;
 506                 }
 507
 508                 /* not yet present - create a candidate for a new connection and then
 509                  * redo the check */
 510                 candidate = rxrpc_alloc_connection(gfp);
 511                 if (IS_ERR(candidate)) {
 512                         _leave(" = %ld", PTR_ERR(candidate));
 513                         return PTR_ERR(candidate);
 514                 }
 515
 516                 candidate->trans = trans;
 517                 candidate->bundle = bundle;
 518                 candidate->service_id = bundle->service_id;
 519                 candidate->epoch = rxrpc_epoch;
 520                 candidate->in_clientflag = 0;
 521                 candidate->out_clientflag = RXRPC_CLIENT_INITIATED;
 522                 candidate->cid = 0;
 523                 candidate->state = RXRPC_CONN_CLIENT;
 524                 candidate->avail_calls = RXRPC_MAXCALLS;
 525                 candidate->security_level = rx->min_sec_level;
 526                 candidate->key = key_get(bundle->key);
 527
 528                 ret = rxrpc_init_client_conn_security(candidate);
 529                 if (ret < 0) {
 530                         key_put(candidate->key);
 531                         kfree(candidate);
 532                         _leave(" = %d [key]", ret);
 533                         return ret;
 534                 }
 535
 536                 write_lock_bh(&rxrpc_connection_lock);
 537                 list_add_tail(&candidate->link, &rxrpc_connections);
 538                 write_unlock_bh(&rxrpc_connection_lock);
 539
 540                 spin_lock(&trans->client_lock);
 541
 542                 list_add(&candidate->bundle_link, &bundle->unused_conns);
 543                 bundle->num_conns++;
 544                 atomic_inc(&bundle->usage);
 545                 atomic_inc(&trans->usage);
 546
 547                 _net("CONNECT new %d on TRANS %d",
 548                      candidate->debug_id, candidate->trans->debug_id);
 549
 550                 rxrpc_assign_connection_id(candidate);
 551                 if (candidate->security)
 552                         candidate->security->prime_packet_security(candidate);
 553
 554                 /* leave the candidate lurking in zombie mode attached to the
 555                  * bundle until we're ready for it */
 556                 rxrpc_put_connection(candidate);
 557                 candidate = NULL;
 558         }
 559
 560         /* we've got a connection with a free channel and we can now attach the
 561          * call to it
 562          * - we're holding the transport's client lock
 563          * - we're holding a reference on the connection
 564          * - we're holding a reference on the bundle
 565          */
 566         for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
 567                 if (!conn->channels[chan])
 568                         goto found_channel;
 569         ASSERT(conn->channels[0] == NULL ||
 570                conn->channels[1] == NULL ||
 571                conn->channels[2] == NULL ||
 572                conn->channels[3] == NULL);
 573         BUG();
 574
 575 found_channel:
 576         conn->channels[chan] = call;
 577         call->conn = conn;
 578         call->channel = chan;
 579         call->cid = conn->cid | htonl(chan);
 580         call->call_id = htonl(++conn->call_counter);
 581
 582         _net("CONNECT client on conn %d chan %d as call %x",
 583              conn->debug_id, chan, ntohl(call->call_id));
 584
 585         ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
 586         spin_unlock(&trans->client_lock);
 587
 588         rxrpc_add_call_ID_to_conn(conn, call);
 589
 590         _leave(" = 0");
 591         return 0;
 592
 593 interrupted_dequeue:
 594         remove_wait_queue(&bundle->chanwait, &myself);
 595         __set_current_state(TASK_RUNNING);
 596 interrupted:
 597         _leave(" = -ERESTARTSYS");
 598         return -ERESTARTSYS;
 599 }
 600
 601 /*
 602  * get a record of an incoming connection
 603  */
 604 struct rxrpc_connection *
 605 rxrpc_incoming_connection(struct rxrpc_transport *trans,
 606                           struct rxrpc_header *hdr,
 607                           gfp_t gfp)
 608 {
 609         struct rxrpc_connection *conn, *candidate = NULL;
 610         struct rb_node *p, **pp;
 611         const char *new = "old";
 612         __be32 epoch;
 613         u32 conn_id;
 614
 615         _enter("");
 616
 617         ASSERT(hdr->flags & RXRPC_CLIENT_INITIATED);
 618
 619         epoch = hdr->epoch;
 620         conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
 621
 622         /* search the connection list first */
 623         read_lock_bh(&trans->conn_lock);
 624
 625         p = trans->server_conns.rb_node;
 626         while (p) {
 627                 conn = rb_entry(p, struct rxrpc_connection, node);
 628
 629                 _debug("maybe %x", conn->real_conn_id);
 630
 631                 if (epoch < conn->epoch)
 632                         p = p->rb_left;
 633                 else if (epoch > conn->epoch)
 634                         p = p->rb_right;
 635                 else if (conn_id < conn->real_conn_id)
 636                         p = p->rb_left;
 637                 else if (conn_id > conn->real_conn_id)
 638                         p = p->rb_right;
 639                 else
 640                         goto found_extant_connection;
 641         }
 642         read_unlock_bh(&trans->conn_lock);
 643
 644         /* not yet present - create a candidate for a new record and then
 645          * redo the search */
 646         candidate = rxrpc_alloc_connection(gfp);
 647         if (!candidate) {
 648                 _leave(" = -ENOMEM");
 649                 return ERR_PTR(-ENOMEM);
 650         }
 651
 652         candidate->trans = trans;
 653         candidate->epoch = hdr->epoch;
 654         candidate->cid = hdr->cid & __constant_cpu_to_be32(RXRPC_CIDMASK);
 655         candidate->service_id = hdr->serviceId;
 656         candidate->security_ix = hdr->securityIndex;
 657         candidate->in_clientflag = RXRPC_CLIENT_INITIATED;
 658         candidate->out_clientflag = 0;
 659         candidate->real_conn_id = conn_id;
 660         candidate->state = RXRPC_CONN_SERVER;
 661         if (candidate->service_id)
 662                 candidate->state = RXRPC_CONN_SERVER_UNSECURED;
 663
 664         write_lock_bh(&trans->conn_lock);
 665
 666         pp = &trans->server_conns.rb_node;
 667         p = NULL;
 668         while (*pp) {
 669                 p = *pp;
 670                 conn = rb_entry(p, struct rxrpc_connection, node);
 671
 672                 if (epoch < conn->epoch)
 673                         pp = &(*pp)->rb_left;
 674                 else if (epoch > conn->epoch)
 675                         pp = &(*pp)->rb_right;
 676                 else if (conn_id < conn->real_conn_id)
 677                         pp = &(*pp)->rb_left;
 678                 else if (conn_id > conn->real_conn_id)
 679                         pp = &(*pp)->rb_right;
 680                 else
 681                         goto found_extant_second;
 682         }
 683
 684         /* we can now add the new candidate to the list */
 685         conn = candidate;
 686         candidate = NULL;
 687         rb_link_node(&conn->node, p, pp);
 688         rb_insert_color(&conn->node, &trans->server_conns);
 689         atomic_inc(&conn->trans->usage);
 690
 691         write_unlock_bh(&trans->conn_lock);
 692
 693         write_lock_bh(&rxrpc_connection_lock);
 694         list_add_tail(&conn->link, &rxrpc_connections);
 695         write_unlock_bh(&rxrpc_connection_lock);
 696
 697         new = "new";
 698
 699 success:
 700         _net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->real_conn_id);
 701
 702         _leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
 703         return conn;
 704
 705         /* we found the connection in the list immediately */
 706 found_extant_connection:
 707         if (hdr->securityIndex != conn->security_ix) {
 708                 read_unlock_bh(&trans->conn_lock);
 709                 goto security_mismatch;
 710         }
 711         atomic_inc(&conn->usage);
 712         read_unlock_bh(&trans->conn_lock);
 713         goto success;
 714
 715         /* we found the connection on the second time through the list */
 716 found_extant_second:
 717         if (hdr->securityIndex != conn->security_ix) {
 718                 write_unlock_bh(&trans->conn_lock);
 719                 goto security_mismatch;
 720         }
 721         atomic_inc(&conn->usage);
 722         write_unlock_bh(&trans->conn_lock);
 723         kfree(candidate);
 724         goto success;
 725
 726 security_mismatch:
 727         kfree(candidate);
 728         _leave(" = -EKEYREJECTED");
 729         return ERR_PTR(-EKEYREJECTED);
 730 }
 731
 732 /*
 733  * find a connection based on transport and RxRPC connection ID for an incoming
 734  * packet
 735  */
 736 struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_transport *trans,
 737                                                struct rxrpc_header *hdr)
 738 {
 739         struct rxrpc_connection *conn;
 740         struct rb_node *p;
 741         __be32 epoch;
 742         u32 conn_id;
 743
 744         _enter(",{%x,%x}", ntohl(hdr->cid), hdr->flags);
 745
 746         read_lock_bh(&trans->conn_lock);
 747
 748         conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
 749         epoch = hdr->epoch;
 750
 751         if (hdr->flags & RXRPC_CLIENT_INITIATED)
 752                 p = trans->server_conns.rb_node;
 753         else
 754                 p = trans->client_conns.rb_node;
 755
 756         while (p) {
 757                 conn = rb_entry(p, struct rxrpc_connection, node);
 758
 759                 _debug("maybe %x", conn->real_conn_id);
 760
 761                 if (epoch < conn->epoch)
 762                         p = p->rb_left;
 763                 else if (epoch > conn->epoch)
 764                         p = p->rb_right;
 765                 else if (conn_id < conn->real_conn_id)
 766                         p = p->rb_left;
 767                 else if (conn_id > conn->real_conn_id)
 768                         p = p->rb_right;
 769                 else
 770                         goto found;
 771         }
 772
 773         read_unlock_bh(&trans->conn_lock);
 774         _leave(" = NULL");
 775         return NULL;
 776
 777 found:
 778         atomic_inc(&conn->usage);
 779         read_unlock_bh(&trans->conn_lock);
 780         _leave(" = %p", conn);
 781         return conn;
 782 }
 783
 784 /*
 785  * release a virtual connection
 786  */
 787 void rxrpc_put_connection(struct rxrpc_connection *conn)
 788 {
 789         _enter("%p{u=%d,d=%d}",
 790                conn, atomic_read(&conn->usage), conn->debug_id);
 791
 792         ASSERTCMP(atomic_read(&conn->usage), >, 0);
 793
 794         conn->put_time = xtime.tv_sec;
 795         if (atomic_dec_and_test(&conn->usage)) {
 796                 _debug("zombie");
 797                 rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 798         }
 799
 800         _leave("");
 801 }
 802
 803 /*
 804  * destroy a virtual connection
 805  */
 806 static void rxrpc_destroy_connection(struct rxrpc_connection *conn)
 807 {
 808         _enter("%p{%d}", conn, atomic_read(&conn->usage));
 809
 810         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 811
 812         _net("DESTROY CONN %d", conn->debug_id);
 813
 814         if (conn->bundle)
 815                 rxrpc_put_bundle(conn->trans, conn->bundle);
 816
 817         ASSERT(RB_EMPTY_ROOT(&conn->calls));
 818         rxrpc_purge_queue(&conn->rx_queue);
 819
 820         rxrpc_clear_conn_security(conn);
 821         rxrpc_put_transport(conn->trans);
 822         kfree(conn);
 823         _leave("");
 824 }
 825
 826 /*
 827  * reap dead connections
 828  */
 829 void rxrpc_connection_reaper(struct work_struct *work)
 830 {
 831         struct rxrpc_connection *conn, *_p;
 832         unsigned long now, earliest, reap_time;
 833
 834         LIST_HEAD(graveyard);
 835
 836         _enter("");
 837
 838         now = xtime.tv_sec;
 839         earliest = ULONG_MAX;
 840
 841         write_lock_bh(&rxrpc_connection_lock);
 842         list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
 843                 _debug("reap CONN %d { u=%d,t=%ld }",
 844                        conn->debug_id, atomic_read(&conn->usage),
 845                        (long) now - (long) conn->put_time);
 846
 847                 if (likely(atomic_read(&conn->usage) > 0))
 848                         continue;
 849
 850                 spin_lock(&conn->trans->client_lock);
 851                 write_lock(&conn->trans->conn_lock);
 852                 reap_time = conn->put_time + rxrpc_connection_timeout;
 853
 854                 if (atomic_read(&conn->usage) > 0) {
 855                         ;
 856                 } else if (reap_time <= now) {
 857                         list_move_tail(&conn->link, &graveyard);
 858                         if (conn->out_clientflag)
 859                                 rb_erase(&conn->node,
 860                                          &conn->trans->client_conns);
 861                         else
 862                                 rb_erase(&conn->node,
 863                                          &conn->trans->server_conns);
 864                         if (conn->bundle) {
 865                                 list_del_init(&conn->bundle_link);
 866                                 conn->bundle->num_conns--;
 867                         }
 868
 869                 } else if (reap_time < earliest) {
 870                         earliest = reap_time;
 871                 }
 872
 873                 write_unlock(&conn->trans->conn_lock);
 874                 spin_unlock(&conn->trans->client_lock);
 875         }
 876         write_unlock_bh(&rxrpc_connection_lock);
 877
 878         if (earliest != ULONG_MAX) {
 879                 _debug("reschedule reaper %ld", (long) earliest - now);
 880                 ASSERTCMP(earliest, >, now);
 881                 rxrpc_queue_delayed_work(&rxrpc_connection_reap,
 882                                          (earliest - now) * HZ);
 883         }
 884
 885         /* then destroy all those pulled out */
 886         while (!list_empty(&graveyard)) {
 887                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 888                                   link);
 889                 list_del_init(&conn->link);
 890
 891                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 892                 rxrpc_destroy_connection(conn);
 893         }
 894
 895         _leave("");
 896 }
 897
 898 /*
 899  * preemptively destroy all the connection records rather than waiting for them
 900  * to time out
 901  */
 902 void __exit rxrpc_destroy_all_connections(void)
 903 {
 904         _enter("");
 905
 906         rxrpc_connection_timeout = 0;
 907         cancel_delayed_work(&rxrpc_connection_reap);
 908         rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 909
 910         _leave("");
 911 }