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/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  */
  24 unsigned int rxrpc_connection_expiry = 10 * 60;
  25
  26 static void rxrpc_connection_reaper(struct work_struct *work);
  27
  28 LIST_HEAD(rxrpc_connections);
  29 DEFINE_RWLOCK(rxrpc_connection_lock);
  30 static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);
  31
  32 /*
  33  * allocate a new client connection bundle
  34  */
  35 static 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  */
  58 static inline
  59 int rxrpc_cmp_bundle(const struct rxrpc_conn_bundle *bundle,
  60                      struct key *key, u16 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  */
  69 struct rxrpc_conn_bundle *rxrpc_get_bundle(struct rxrpc_sock *rx,
  70                                            struct rxrpc_transport *trans,
  71                                            struct key *key,
  72                                            u16 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, 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 */
 147 found_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 */
 159 found_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  */
 175 void 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  */
 198 static 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_wire_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  */
 228 static 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 cid;
 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         cid = conn->trans->conn_idcounter;
 245
 246 attempt_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 (cid < xconn->cid)
 259                         p = &(*p)->rb_left;
 260                 else if (cid > xconn->cid)
 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->cid = cid;
 272         write_unlock_bh(&conn->trans->conn_lock);
 273         _leave(" [CID %x]", cid);
 274         return;
 275
 276         /* we found a connection with the proposed ID - walk the tree from that
 277          * point looking for the next unused ID */
 278 id_exists:
 279         for (;;) {
 280                 cid += RXRPC_CID_INC;
 281                 if (cid < RXRPC_CID_INC) {
 282                         cid = RXRPC_CID_INC;
 283                         conn->trans->conn_idcounter = cid;
 284                         goto attempt_insertion;
 285                 }
 286
 287                 parent = rb_next(parent);
 288                 if (!parent)
 289                         goto attempt_insertion;
 290
 291                 xconn = rb_entry(parent, struct rxrpc_connection, node);
 292                 if (epoch < xconn->epoch ||
 293                     cid < xconn->cid)
 294                         goto attempt_insertion;
 295         }
 296 }
 297
 298 /*
 299  * add a call to a connection's call-by-ID tree
 300  */
 301 static void rxrpc_add_call_ID_to_conn(struct rxrpc_connection *conn,
 302                                       struct rxrpc_call *call)
 303 {
 304         struct rxrpc_call *xcall;
 305         struct rb_node *parent, **p;
 306         __be32 call_id;
 307
 308         write_lock_bh(&conn->lock);
 309
 310         call_id = call->call_id;
 311         p = &conn->calls.rb_node;
 312         parent = NULL;
 313         while (*p) {
 314                 parent = *p;
 315                 xcall = rb_entry(parent, struct rxrpc_call, conn_node);
 316
 317                 if (call_id < xcall->call_id)
 318                         p = &(*p)->rb_left;
 319                 else if (call_id > xcall->call_id)
 320                         p = &(*p)->rb_right;
 321                 else
 322                         BUG();
 323         }
 324
 325         rb_link_node(&call->conn_node, parent, p);
 326         rb_insert_color(&call->conn_node, &conn->calls);
 327
 328         write_unlock_bh(&conn->lock);
 329 }
 330
 331 /*
 332  * connect a call on an exclusive connection
 333  */
 334 static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
 335                                    struct rxrpc_transport *trans,
 336                                    u16 service_id,
 337                                    struct rxrpc_call *call,
 338                                    gfp_t gfp)
 339 {
 340         struct rxrpc_connection *conn;
 341         int chan, ret;
 342
 343         _enter("");
 344
 345         conn = rx->conn;
 346         if (!conn) {
 347                 /* not yet present - create a candidate for a new connection
 348                  * and then redo the check */
 349                 conn = rxrpc_alloc_connection(gfp);
 350                 if (!conn) {
 351                         _leave(" = -ENOMEM");
 352                         return -ENOMEM;
 353                 }
 354
 355                 conn->trans = trans;
 356                 conn->bundle = NULL;
 357                 conn->service_id = service_id;
 358                 conn->epoch = rxrpc_epoch;
 359                 conn->in_clientflag = 0;
 360                 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
 361                 conn->cid = 0;
 362                 conn->state = RXRPC_CONN_CLIENT;
 363                 conn->avail_calls = RXRPC_MAXCALLS - 1;
 364                 conn->security_level = rx->min_sec_level;
 365                 conn->key = key_get(rx->key);
 366
 367                 ret = rxrpc_init_client_conn_security(conn);
 368                 if (ret < 0) {
 369                         key_put(conn->key);
 370                         kfree(conn);
 371                         _leave(" = %d [key]", ret);
 372                         return ret;
 373                 }
 374
 375                 write_lock_bh(&rxrpc_connection_lock);
 376                 list_add_tail(&conn->link, &rxrpc_connections);
 377                 write_unlock_bh(&rxrpc_connection_lock);
 378
 379                 spin_lock(&trans->client_lock);
 380                 atomic_inc(&trans->usage);
 381
 382                 _net("CONNECT EXCL new %d on TRANS %d",
 383                      conn->debug_id, conn->trans->debug_id);
 384
 385                 rxrpc_assign_connection_id(conn);
 386                 rx->conn = conn;
 387         } else {
 388                 spin_lock(&trans->client_lock);
 389         }
 390
 391         /* we've got a connection with a free channel and we can now attach the
 392          * call to it
 393          * - we're holding the transport's client lock
 394          * - we're holding a reference on the connection
 395          */
 396         for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
 397                 if (!conn->channels[chan])
 398                         goto found_channel;
 399         goto no_free_channels;
 400
 401 found_channel:
 402         atomic_inc(&conn->usage);
 403         conn->channels[chan] = call;
 404         call->conn = conn;
 405         call->channel = chan;
 406         call->cid = conn->cid | chan;
 407         call->call_id = ++conn->call_counter;
 408
 409         _net("CONNECT client on conn %d chan %d as call %x",
 410              conn->debug_id, chan, call->call_id);
 411
 412         spin_unlock(&trans->client_lock);
 413
 414         rxrpc_add_call_ID_to_conn(conn, call);
 415         _leave(" = 0");
 416         return 0;
 417
 418 no_free_channels:
 419         spin_unlock(&trans->client_lock);
 420         _leave(" = -ENOSR");
 421         return -ENOSR;
 422 }
 423
 424 /*
 425  * find a connection for a call
 426  * - called in process context with IRQs enabled
 427  */
 428 int rxrpc_connect_call(struct rxrpc_sock *rx,
 429                        struct rxrpc_transport *trans,
 430                        struct rxrpc_conn_bundle *bundle,
 431                        struct rxrpc_call *call,
 432                        gfp_t gfp)
 433 {
 434         struct rxrpc_connection *conn, *candidate;
 435         int chan, ret;
 436
 437         DECLARE_WAITQUEUE(myself, current);
 438
 439         _enter("%p,%lx,", rx, call->user_call_ID);
 440
 441         if (test_bit(RXRPC_SOCK_EXCLUSIVE_CONN, &rx->flags))
 442                 return rxrpc_connect_exclusive(rx, trans, bundle->service_id,
 443                                                call, gfp);
 444
 445         spin_lock(&trans->client_lock);
 446         for (;;) {
 447                 /* see if the bundle has a call slot available */
 448                 if (!list_empty(&bundle->avail_conns)) {
 449                         _debug("avail");
 450                         conn = list_entry(bundle->avail_conns.next,
 451                                           struct rxrpc_connection,
 452                                           bundle_link);
 453                         if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
 454                                 list_del_init(&conn->bundle_link);
 455                                 bundle->num_conns--;
 456                                 continue;
 457                         }
 458                         if (--conn->avail_calls == 0)
 459                                 list_move(&conn->bundle_link,
 460                                           &bundle->busy_conns);
 461                         ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
 462                         ASSERT(conn->channels[0] == NULL ||
 463                                conn->channels[1] == NULL ||
 464                                conn->channels[2] == NULL ||
 465                                conn->channels[3] == NULL);
 466                         atomic_inc(&conn->usage);
 467                         break;
 468                 }
 469
 470                 if (!list_empty(&bundle->unused_conns)) {
 471                         _debug("unused");
 472                         conn = list_entry(bundle->unused_conns.next,
 473                                           struct rxrpc_connection,
 474                                           bundle_link);
 475                         if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
 476                                 list_del_init(&conn->bundle_link);
 477                                 bundle->num_conns--;
 478                                 continue;
 479                         }
 480                         ASSERTCMP(conn->avail_calls, ==, RXRPC_MAXCALLS);
 481                         conn->avail_calls = RXRPC_MAXCALLS - 1;
 482                         ASSERT(conn->channels[0] == NULL &&
 483                                conn->channels[1] == NULL &&
 484                                conn->channels[2] == NULL &&
 485                                conn->channels[3] == NULL);
 486                         atomic_inc(&conn->usage);
 487                         list_move(&conn->bundle_link, &bundle->avail_conns);
 488                         break;
 489                 }
 490
 491                 /* need to allocate a new connection */
 492                 _debug("get new conn [%d]", bundle->num_conns);
 493
 494                 spin_unlock(&trans->client_lock);
 495
 496                 if (signal_pending(current))
 497                         goto interrupted;
 498
 499                 if (bundle->num_conns >= 20) {
 500                         _debug("too many conns");
 501
 502                         if (!gfpflags_allow_blocking(gfp)) {
 503                                 _leave(" = -EAGAIN");
 504                                 return -EAGAIN;
 505                         }
 506
 507                         add_wait_queue(&bundle->chanwait, &myself);
 508                         for (;;) {
 509                                 set_current_state(TASK_INTERRUPTIBLE);
 510                                 if (bundle->num_conns < 20 ||
 511                                     !list_empty(&bundle->unused_conns) ||
 512                                     !list_empty(&bundle->avail_conns))
 513                                         break;
 514                                 if (signal_pending(current))
 515                                         goto interrupted_dequeue;
 516                                 schedule();
 517                         }
 518                         remove_wait_queue(&bundle->chanwait, &myself);
 519                         __set_current_state(TASK_RUNNING);
 520                         spin_lock(&trans->client_lock);
 521                         continue;
 522                 }
 523
 524                 /* not yet present - create a candidate for a new connection and then
 525                  * redo the check */
 526                 candidate = rxrpc_alloc_connection(gfp);
 527                 if (!candidate) {
 528                         _leave(" = -ENOMEM");
 529                         return -ENOMEM;
 530                 }
 531
 532                 candidate->trans = trans;
 533                 candidate->bundle = bundle;
 534                 candidate->service_id = bundle->service_id;
 535                 candidate->epoch = rxrpc_epoch;
 536                 candidate->in_clientflag = 0;
 537                 candidate->out_clientflag = RXRPC_CLIENT_INITIATED;
 538                 candidate->cid = 0;
 539                 candidate->state = RXRPC_CONN_CLIENT;
 540                 candidate->avail_calls = RXRPC_MAXCALLS;
 541                 candidate->security_level = rx->min_sec_level;
 542                 candidate->key = key_get(bundle->key);
 543
 544                 ret = rxrpc_init_client_conn_security(candidate);
 545                 if (ret < 0) {
 546                         key_put(candidate->key);
 547                         kfree(candidate);
 548                         _leave(" = %d [key]", ret);
 549                         return ret;
 550                 }
 551
 552                 write_lock_bh(&rxrpc_connection_lock);
 553                 list_add_tail(&candidate->link, &rxrpc_connections);
 554                 write_unlock_bh(&rxrpc_connection_lock);
 555
 556                 spin_lock(&trans->client_lock);
 557
 558                 list_add(&candidate->bundle_link, &bundle->unused_conns);
 559                 bundle->num_conns++;
 560                 atomic_inc(&bundle->usage);
 561                 atomic_inc(&trans->usage);
 562
 563                 _net("CONNECT new %d on TRANS %d",
 564                      candidate->debug_id, candidate->trans->debug_id);
 565
 566                 rxrpc_assign_connection_id(candidate);
 567                 if (candidate->security)
 568                         candidate->security->prime_packet_security(candidate);
 569
 570                 /* leave the candidate lurking in zombie mode attached to the
 571                  * bundle until we're ready for it */
 572                 rxrpc_put_connection(candidate);
 573                 candidate = NULL;
 574         }
 575
 576         /* we've got a connection with a free channel and we can now attach the
 577          * call to it
 578          * - we're holding the transport's client lock
 579          * - we're holding a reference on the connection
 580          * - we're holding a reference on the bundle
 581          */
 582         for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
 583                 if (!conn->channels[chan])
 584                         goto found_channel;
 585         ASSERT(conn->channels[0] == NULL ||
 586                conn->channels[1] == NULL ||
 587                conn->channels[2] == NULL ||
 588                conn->channels[3] == NULL);
 589         BUG();
 590
 591 found_channel:
 592         conn->channels[chan] = call;
 593         call->conn = conn;
 594         call->channel = chan;
 595         call->cid = conn->cid | chan;
 596         call->call_id = ++conn->call_counter;
 597
 598         _net("CONNECT client on conn %d chan %d as call %x",
 599              conn->debug_id, chan, call->call_id);
 600
 601         ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
 602         spin_unlock(&trans->client_lock);
 603
 604         rxrpc_add_call_ID_to_conn(conn, call);
 605
 606         _leave(" = 0");
 607         return 0;
 608
 609 interrupted_dequeue:
 610         remove_wait_queue(&bundle->chanwait, &myself);
 611         __set_current_state(TASK_RUNNING);
 612 interrupted:
 613         _leave(" = -ERESTARTSYS");
 614         return -ERESTARTSYS;
 615 }
 616
 617 /*
 618  * get a record of an incoming connection
 619  */
 620 struct rxrpc_connection *
 621 rxrpc_incoming_connection(struct rxrpc_transport *trans,
 622                           struct rxrpc_host_header *hdr,
 623                           gfp_t gfp)
 624 {
 625         struct rxrpc_connection *conn, *candidate = NULL;
 626         struct rb_node *p, **pp;
 627         const char *new = "old";
 628         __be32 epoch;
 629         u32 cid;
 630
 631         _enter("");
 632
 633         ASSERT(hdr->flags & RXRPC_CLIENT_INITIATED);
 634
 635         epoch = hdr->epoch;
 636         cid = hdr->cid & RXRPC_CIDMASK;
 637
 638         /* search the connection list first */
 639         read_lock_bh(&trans->conn_lock);
 640
 641         p = trans->server_conns.rb_node;
 642         while (p) {
 643                 conn = rb_entry(p, struct rxrpc_connection, node);
 644
 645                 _debug("maybe %x", conn->cid);
 646
 647                 if (epoch < conn->epoch)
 648                         p = p->rb_left;
 649                 else if (epoch > conn->epoch)
 650                         p = p->rb_right;
 651                 else if (cid < conn->cid)
 652                         p = p->rb_left;
 653                 else if (cid > conn->cid)
 654                         p = p->rb_right;
 655                 else
 656                         goto found_extant_connection;
 657         }
 658         read_unlock_bh(&trans->conn_lock);
 659
 660         /* not yet present - create a candidate for a new record and then
 661          * redo the search */
 662         candidate = rxrpc_alloc_connection(gfp);
 663         if (!candidate) {
 664                 _leave(" = -ENOMEM");
 665                 return ERR_PTR(-ENOMEM);
 666         }
 667
 668         candidate->trans = trans;
 669         candidate->epoch = hdr->epoch;
 670         candidate->cid = hdr->cid & RXRPC_CIDMASK;
 671         candidate->service_id = hdr->serviceId;
 672         candidate->security_ix = hdr->securityIndex;
 673         candidate->in_clientflag = RXRPC_CLIENT_INITIATED;
 674         candidate->out_clientflag = 0;
 675         candidate->state = RXRPC_CONN_SERVER;
 676         if (candidate->service_id)
 677                 candidate->state = RXRPC_CONN_SERVER_UNSECURED;
 678
 679         write_lock_bh(&trans->conn_lock);
 680
 681         pp = &trans->server_conns.rb_node;
 682         p = NULL;
 683         while (*pp) {
 684                 p = *pp;
 685                 conn = rb_entry(p, struct rxrpc_connection, node);
 686
 687                 if (epoch < conn->epoch)
 688                         pp = &(*pp)->rb_left;
 689                 else if (epoch > conn->epoch)
 690                         pp = &(*pp)->rb_right;
 691                 else if (cid < conn->cid)
 692                         pp = &(*pp)->rb_left;
 693                 else if (cid > conn->cid)
 694                         pp = &(*pp)->rb_right;
 695                 else
 696                         goto found_extant_second;
 697         }
 698
 699         /* we can now add the new candidate to the list */
 700         conn = candidate;
 701         candidate = NULL;
 702         rb_link_node(&conn->node, p, pp);
 703         rb_insert_color(&conn->node, &trans->server_conns);
 704         atomic_inc(&conn->trans->usage);
 705
 706         write_unlock_bh(&trans->conn_lock);
 707
 708         write_lock_bh(&rxrpc_connection_lock);
 709         list_add_tail(&conn->link, &rxrpc_connections);
 710         write_unlock_bh(&rxrpc_connection_lock);
 711
 712         new = "new";
 713
 714 success:
 715         _net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->cid);
 716
 717         _leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
 718         return conn;
 719
 720         /* we found the connection in the list immediately */
 721 found_extant_connection:
 722         if (hdr->securityIndex != conn->security_ix) {
 723                 read_unlock_bh(&trans->conn_lock);
 724                 goto security_mismatch;
 725         }
 726         atomic_inc(&conn->usage);
 727         read_unlock_bh(&trans->conn_lock);
 728         goto success;
 729
 730         /* we found the connection on the second time through the list */
 731 found_extant_second:
 732         if (hdr->securityIndex != conn->security_ix) {
 733                 write_unlock_bh(&trans->conn_lock);
 734                 goto security_mismatch;
 735         }
 736         atomic_inc(&conn->usage);
 737         write_unlock_bh(&trans->conn_lock);
 738         kfree(candidate);
 739         goto success;
 740
 741 security_mismatch:
 742         kfree(candidate);
 743         _leave(" = -EKEYREJECTED");
 744         return ERR_PTR(-EKEYREJECTED);
 745 }
 746
 747 /*
 748  * find a connection based on transport and RxRPC connection ID for an incoming
 749  * packet
 750  */
 751 struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_transport *trans,
 752                                                struct rxrpc_host_header *hdr)
 753 {
 754         struct rxrpc_connection *conn;
 755         struct rb_node *p;
 756         u32 epoch, cid;
 757
 758         _enter(",{%x,%x}", hdr->cid, hdr->flags);
 759
 760         read_lock_bh(&trans->conn_lock);
 761
 762         cid = hdr->cid & RXRPC_CIDMASK;
 763         epoch = hdr->epoch;
 764
 765         if (hdr->flags & RXRPC_CLIENT_INITIATED)
 766                 p = trans->server_conns.rb_node;
 767         else
 768                 p = trans->client_conns.rb_node;
 769
 770         while (p) {
 771                 conn = rb_entry(p, struct rxrpc_connection, node);
 772
 773                 _debug("maybe %x", conn->cid);
 774
 775                 if (epoch < conn->epoch)
 776                         p = p->rb_left;
 777                 else if (epoch > conn->epoch)
 778                         p = p->rb_right;
 779                 else if (cid < conn->cid)
 780                         p = p->rb_left;
 781                 else if (cid > conn->cid)
 782                         p = p->rb_right;
 783                 else
 784                         goto found;
 785         }
 786
 787         read_unlock_bh(&trans->conn_lock);
 788         _leave(" = NULL");
 789         return NULL;
 790
 791 found:
 792         atomic_inc(&conn->usage);
 793         read_unlock_bh(&trans->conn_lock);
 794         _leave(" = %p", conn);
 795         return conn;
 796 }
 797
 798 /*
 799  * release a virtual connection
 800  */
 801 void rxrpc_put_connection(struct rxrpc_connection *conn)
 802 {
 803         _enter("%p{u=%d,d=%d}",
 804                conn, atomic_read(&conn->usage), conn->debug_id);
 805
 806         ASSERTCMP(atomic_read(&conn->usage), >, 0);
 807
 808         conn->put_time = ktime_get_seconds();
 809         if (atomic_dec_and_test(&conn->usage)) {
 810                 _debug("zombie");
 811                 rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 812         }
 813
 814         _leave("");
 815 }
 816
 817 /*
 818  * destroy a virtual connection
 819  */
 820 static void rxrpc_destroy_connection(struct rxrpc_connection *conn)
 821 {
 822         _enter("%p{%d}", conn, atomic_read(&conn->usage));
 823
 824         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 825
 826         _net("DESTROY CONN %d", conn->debug_id);
 827
 828         if (conn->bundle)
 829                 rxrpc_put_bundle(conn->trans, conn->bundle);
 830
 831         ASSERT(RB_EMPTY_ROOT(&conn->calls));
 832         rxrpc_purge_queue(&conn->rx_queue);
 833
 834         rxrpc_clear_conn_security(conn);
 835         rxrpc_put_transport(conn->trans);
 836         kfree(conn);
 837         _leave("");
 838 }
 839
 840 /*
 841  * reap dead connections
 842  */
 843 static void rxrpc_connection_reaper(struct work_struct *work)
 844 {
 845         struct rxrpc_connection *conn, *_p;
 846         unsigned long now, earliest, reap_time;
 847
 848         LIST_HEAD(graveyard);
 849
 850         _enter("");
 851
 852         now = ktime_get_seconds();
 853         earliest = ULONG_MAX;
 854
 855         write_lock_bh(&rxrpc_connection_lock);
 856         list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
 857                 _debug("reap CONN %d { u=%d,t=%ld }",
 858                        conn->debug_id, atomic_read(&conn->usage),
 859                        (long) now - (long) conn->put_time);
 860
 861                 if (likely(atomic_read(&conn->usage) > 0))
 862                         continue;
 863
 864                 spin_lock(&conn->trans->client_lock);
 865                 write_lock(&conn->trans->conn_lock);
 866                 reap_time = conn->put_time + rxrpc_connection_expiry;
 867
 868                 if (atomic_read(&conn->usage) > 0) {
 869                         ;
 870                 } else if (reap_time <= now) {
 871                         list_move_tail(&conn->link, &graveyard);
 872                         if (conn->out_clientflag)
 873                                 rb_erase(&conn->node,
 874                                          &conn->trans->client_conns);
 875                         else
 876                                 rb_erase(&conn->node,
 877                                          &conn->trans->server_conns);
 878                         if (conn->bundle) {
 879                                 list_del_init(&conn->bundle_link);
 880                                 conn->bundle->num_conns--;
 881                         }
 882
 883                 } else if (reap_time < earliest) {
 884                         earliest = reap_time;
 885                 }
 886
 887                 write_unlock(&conn->trans->conn_lock);
 888                 spin_unlock(&conn->trans->client_lock);
 889         }
 890         write_unlock_bh(&rxrpc_connection_lock);
 891
 892         if (earliest != ULONG_MAX) {
 893                 _debug("reschedule reaper %ld", (long) earliest - now);
 894                 ASSERTCMP(earliest, >, now);
 895                 rxrpc_queue_delayed_work(&rxrpc_connection_reap,
 896                                          (earliest - now) * HZ);
 897         }
 898
 899         /* then destroy all those pulled out */
 900         while (!list_empty(&graveyard)) {
 901                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 902                                   link);
 903                 list_del_init(&conn->link);
 904
 905                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 906                 rxrpc_destroy_connection(conn);
 907         }
 908
 909         _leave("");
 910 }
 911
 912 /*
 913  * preemptively destroy all the connection records rather than waiting for them
 914  * to time out
 915  */
 916 void __exit rxrpc_destroy_all_connections(void)
 917 {
 918         _enter("");
 919
 920         rxrpc_connection_expiry = 0;
 921         cancel_delayed_work(&rxrpc_connection_reap);
 922         rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 923
 924         _leave("");
 925 }