net/rxrpc/conn_object.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* RxRPC virtual connection handler, common bits.
   3  *
   4  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/module.h>
  11 #include <linux/slab.h>
  12 #include <linux/net.h>
  13 #include <linux/skbuff.h>
  14 #include "ar-internal.h"
  15
  16 /*
  17  * Time till a connection expires after last use (in seconds).
  18  */
  19 unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
  20 unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
  21
  22 static void rxrpc_clean_up_connection(struct work_struct *work);
  23 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
  24                                          unsigned long reap_at);
  25
  26 void rxrpc_poke_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
  27 {
  28         struct rxrpc_local *local = conn->local;
  29         bool busy;
  30
  31         if (WARN_ON_ONCE(!local))
  32                 return;
  33
  34         spin_lock_bh(&local->lock);
  35         busy = !list_empty(&conn->attend_link);
  36         if (!busy) {
  37                 rxrpc_get_connection(conn, why);
  38                 list_add_tail(&conn->attend_link, &local->conn_attend_q);
  39         }
  40         spin_unlock_bh(&local->lock);
  41         rxrpc_wake_up_io_thread(local);
  42 }
  43
  44 static void rxrpc_connection_timer(struct timer_list *timer)
  45 {
  46         struct rxrpc_connection *conn =
  47                 container_of(timer, struct rxrpc_connection, timer);
  48
  49         rxrpc_poke_conn(conn, rxrpc_conn_get_poke_timer);
  50 }
  51
  52 /*
  53  * allocate a new connection
  54  */
  55 struct rxrpc_connection *rxrpc_alloc_connection(struct rxrpc_net *rxnet,
  56                                                 gfp_t gfp)
  57 {
  58         struct rxrpc_connection *conn;
  59
  60         _enter("");
  61
  62         conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
  63         if (conn) {
  64                 INIT_LIST_HEAD(&conn->cache_link);
  65                 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
  66                 INIT_WORK(&conn->processor, rxrpc_process_connection);
  67                 INIT_WORK(&conn->destructor, rxrpc_clean_up_connection);
  68                 INIT_LIST_HEAD(&conn->proc_link);
  69                 INIT_LIST_HEAD(&conn->link);
  70                 skb_queue_head_init(&conn->rx_queue);
  71                 conn->rxnet = rxnet;
  72                 conn->security = &rxrpc_no_security;
  73                 spin_lock_init(&conn->state_lock);
  74                 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
  75                 conn->idle_timestamp = jiffies;
  76         }
  77
  78         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
  79         return conn;
  80 }
  81
  82 /*
  83  * Look up a connection in the cache by protocol parameters.
  84  *
  85  * If successful, a pointer to the connection is returned, but no ref is taken.
  86  * NULL is returned if there is no match.
  87  *
  88  * When searching for a service call, if we find a peer but no connection, we
  89  * return that through *_peer in case we need to create a new service call.
  90  *
  91  * The caller must be holding the RCU read lock.
  92  */
  93 struct rxrpc_connection *rxrpc_find_client_connection_rcu(struct rxrpc_local *local,
  94                                                           struct sockaddr_rxrpc *srx,
  95                                                           struct sk_buff *skb)
  96 {
  97         struct rxrpc_connection *conn;
  98         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  99         struct rxrpc_peer *peer;
 100
 101         _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
 102
 103         /* Look up client connections by connection ID alone as their
 104          * IDs are unique for this machine.
 105          */
 106         conn = idr_find(&local->conn_ids, sp->hdr.cid >> RXRPC_CIDSHIFT);
 107         if (!conn || refcount_read(&conn->ref) == 0) {
 108                 _debug("no conn");
 109                 goto not_found;
 110         }
 111
 112         if (conn->proto.epoch != sp->hdr.epoch ||
 113             conn->local != local)
 114                 goto not_found;
 115
 116         peer = conn->peer;
 117         switch (srx->transport.family) {
 118         case AF_INET:
 119                 if (peer->srx.transport.sin.sin_port !=
 120                     srx->transport.sin.sin_port ||
 121                     peer->srx.transport.sin.sin_addr.s_addr !=
 122                     srx->transport.sin.sin_addr.s_addr)
 123                         goto not_found;
 124                 break;
 125 #ifdef CONFIG_AF_RXRPC_IPV6
 126         case AF_INET6:
 127                 if (peer->srx.transport.sin6.sin6_port !=
 128                     srx->transport.sin6.sin6_port ||
 129                     memcmp(&peer->srx.transport.sin6.sin6_addr,
 130                            &srx->transport.sin6.sin6_addr,
 131                            sizeof(struct in6_addr)) != 0)
 132                         goto not_found;
 133                 break;
 134 #endif
 135         default:
 136                 BUG();
 137         }
 138
 139         _leave(" = %p", conn);
 140         return conn;
 141
 142 not_found:
 143         _leave(" = NULL");
 144         return NULL;
 145 }
 146
 147 /*
 148  * Disconnect a call and clear any channel it occupies when that call
 149  * terminates.  The caller must hold the channel_lock and must release the
 150  * call's ref on the connection.
 151  */
 152 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
 153                              struct rxrpc_call *call)
 154 {
 155         struct rxrpc_channel *chan =
 156                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
 157
 158         _enter("%d,%x", conn->debug_id, call->cid);
 159
 160         if (rcu_access_pointer(chan->call) == call) {
 161                 /* Save the result of the call so that we can repeat it if necessary
 162                  * through the channel, whilst disposing of the actual call record.
 163                  */
 164                 trace_rxrpc_disconnect_call(call);
 165                 switch (call->completion) {
 166                 case RXRPC_CALL_SUCCEEDED:
 167                         chan->last_seq = call->rx_highest_seq;
 168                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 169                         break;
 170                 case RXRPC_CALL_LOCALLY_ABORTED:
 171                         chan->last_abort = call->abort_code;
 172                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 173                         break;
 174                 default:
 175                         chan->last_abort = RX_CALL_DEAD;
 176                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 177                         break;
 178                 }
 179
 180                 /* Sync with rxrpc_conn_retransmit(). */
 181                 smp_wmb();
 182                 chan->last_call = chan->call_id;
 183                 chan->call_id = chan->call_counter;
 184
 185                 rcu_assign_pointer(chan->call, NULL);
 186         }
 187
 188         _leave("");
 189 }
 190
 191 /*
 192  * Disconnect a call and clear any channel it occupies when that call
 193  * terminates.
 194  */
 195 void rxrpc_disconnect_call(struct rxrpc_call *call)
 196 {
 197         struct rxrpc_connection *conn = call->conn;
 198
 199         set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
 200         rxrpc_see_call(call, rxrpc_call_see_disconnected);
 201
 202         call->peer->cong_ssthresh = call->cong_ssthresh;
 203
 204         if (!hlist_unhashed(&call->error_link)) {
 205                 spin_lock(&call->peer->lock);
 206                 hlist_del_init(&call->error_link);
 207                 spin_unlock(&call->peer->lock);
 208         }
 209
 210         if (rxrpc_is_client_call(call)) {
 211                 rxrpc_disconnect_client_call(conn->bundle, call);
 212         } else {
 213                 spin_lock(&conn->bundle->channel_lock);
 214                 __rxrpc_disconnect_call(conn, call);
 215                 spin_unlock(&conn->bundle->channel_lock);
 216
 217                 conn->idle_timestamp = jiffies;
 218                 if (atomic_dec_and_test(&conn->active))
 219                         rxrpc_set_service_reap_timer(conn->rxnet,
 220                                                      jiffies + rxrpc_connection_expiry);
 221         }
 222
 223         rxrpc_put_call(call, rxrpc_call_put_io_thread);
 224 }
 225
 226 /*
 227  * Queue a connection's work processor, getting a ref to pass to the work
 228  * queue.
 229  */
 230 void rxrpc_queue_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
 231 {
 232         if (atomic_read(&conn->active) >= 0 &&
 233             rxrpc_queue_work(&conn->processor))
 234                 rxrpc_see_connection(conn, why);
 235 }
 236
 237 /*
 238  * Note the re-emergence of a connection.
 239  */
 240 void rxrpc_see_connection(struct rxrpc_connection *conn,
 241                           enum rxrpc_conn_trace why)
 242 {
 243         if (conn) {
 244                 int r = refcount_read(&conn->ref);
 245
 246                 trace_rxrpc_conn(conn->debug_id, r, why);
 247         }
 248 }
 249
 250 /*
 251  * Get a ref on a connection.
 252  */
 253 struct rxrpc_connection *rxrpc_get_connection(struct rxrpc_connection *conn,
 254                                               enum rxrpc_conn_trace why)
 255 {
 256         int r;
 257
 258         __refcount_inc(&conn->ref, &r);
 259         trace_rxrpc_conn(conn->debug_id, r + 1, why);
 260         return conn;
 261 }
 262
 263 /*
 264  * Try to get a ref on a connection.
 265  */
 266 struct rxrpc_connection *
 267 rxrpc_get_connection_maybe(struct rxrpc_connection *conn,
 268                            enum rxrpc_conn_trace why)
 269 {
 270         int r;
 271
 272         if (conn) {
 273                 if (__refcount_inc_not_zero(&conn->ref, &r))
 274                         trace_rxrpc_conn(conn->debug_id, r + 1, why);
 275                 else
 276                         conn = NULL;
 277         }
 278         return conn;
 279 }
 280
 281 /*
 282  * Set the service connection reap timer.
 283  */
 284 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
 285                                          unsigned long reap_at)
 286 {
 287         if (rxnet->live)
 288                 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
 289 }
 290
 291 /*
 292  * destroy a virtual connection
 293  */
 294 static void rxrpc_rcu_free_connection(struct rcu_head *rcu)
 295 {
 296         struct rxrpc_connection *conn =
 297                 container_of(rcu, struct rxrpc_connection, rcu);
 298         struct rxrpc_net *rxnet = conn->rxnet;
 299
 300         _enter("{%d,u=%d}", conn->debug_id, refcount_read(&conn->ref));
 301
 302         trace_rxrpc_conn(conn->debug_id, refcount_read(&conn->ref),
 303                          rxrpc_conn_free);
 304         kfree(conn);
 305
 306         if (atomic_dec_and_test(&rxnet->nr_conns))
 307                 wake_up_var(&rxnet->nr_conns);
 308 }
 309
 310 /*
 311  * Clean up a dead connection.
 312  */
 313 static void rxrpc_clean_up_connection(struct work_struct *work)
 314 {
 315         struct rxrpc_connection *conn =
 316                 container_of(work, struct rxrpc_connection, destructor);
 317         struct rxrpc_net *rxnet = conn->rxnet;
 318
 319         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 320                !rcu_access_pointer(conn->channels[1].call) &&
 321                !rcu_access_pointer(conn->channels[2].call) &&
 322                !rcu_access_pointer(conn->channels[3].call));
 323         ASSERT(list_empty(&conn->cache_link));
 324
 325         del_timer_sync(&conn->timer);
 326         cancel_work_sync(&conn->processor); /* Processing may restart the timer */
 327         del_timer_sync(&conn->timer);
 328
 329         write_lock(&rxnet->conn_lock);
 330         list_del_init(&conn->proc_link);
 331         write_unlock(&rxnet->conn_lock);
 332
 333         rxrpc_purge_queue(&conn->rx_queue);
 334
 335         rxrpc_kill_client_conn(conn);
 336
 337         conn->security->clear(conn);
 338         key_put(conn->key);
 339         rxrpc_put_bundle(conn->bundle, rxrpc_bundle_put_conn);
 340         rxrpc_put_peer(conn->peer, rxrpc_peer_put_conn);
 341         rxrpc_put_local(conn->local, rxrpc_local_put_kill_conn);
 342
 343         /* Drain the Rx queue.  Note that even though we've unpublished, an
 344          * incoming packet could still be being added to our Rx queue, so we
 345          * will need to drain it again in the RCU cleanup handler.
 346          */
 347         rxrpc_purge_queue(&conn->rx_queue);
 348
 349         call_rcu(&conn->rcu, rxrpc_rcu_free_connection);
 350 }
 351
 352 /*
 353  * Drop a ref on a connection.
 354  */
 355 void rxrpc_put_connection(struct rxrpc_connection *conn,
 356                           enum rxrpc_conn_trace why)
 357 {
 358         unsigned int debug_id;
 359         bool dead;
 360         int r;
 361
 362         if (!conn)
 363                 return;
 364
 365         debug_id = conn->debug_id;
 366         dead = __refcount_dec_and_test(&conn->ref, &r);
 367         trace_rxrpc_conn(debug_id, r - 1, why);
 368         if (dead) {
 369                 del_timer(&conn->timer);
 370                 cancel_work(&conn->processor);
 371
 372                 if (in_softirq() || work_busy(&conn->processor) ||
 373                     timer_pending(&conn->timer))
 374                         /* Can't use the rxrpc workqueue as we need to cancel/flush
 375                          * something that may be running/waiting there.
 376                          */
 377                         schedule_work(&conn->destructor);
 378                 else
 379                         rxrpc_clean_up_connection(&conn->destructor);
 380         }
 381 }
 382
 383 /*
 384  * reap dead service connections
 385  */
 386 void rxrpc_service_connection_reaper(struct work_struct *work)
 387 {
 388         struct rxrpc_connection *conn, *_p;
 389         struct rxrpc_net *rxnet =
 390                 container_of(work, struct rxrpc_net, service_conn_reaper);
 391         unsigned long expire_at, earliest, idle_timestamp, now;
 392         int active;
 393
 394         LIST_HEAD(graveyard);
 395
 396         _enter("");
 397
 398         now = jiffies;
 399         earliest = now + MAX_JIFFY_OFFSET;
 400
 401         write_lock(&rxnet->conn_lock);
 402         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 403                 ASSERTCMP(atomic_read(&conn->active), >=, 0);
 404                 if (likely(atomic_read(&conn->active) > 0))
 405                         continue;
 406                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 407                         continue;
 408
 409                 if (rxnet->live && !conn->local->dead) {
 410                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
 411                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
 412                         if (conn->local->service_closed)
 413                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
 414
 415                         _debug("reap CONN %d { a=%d,t=%ld }",
 416                                conn->debug_id, atomic_read(&conn->active),
 417                                (long)expire_at - (long)now);
 418
 419                         if (time_before(now, expire_at)) {
 420                                 if (time_before(expire_at, earliest))
 421                                         earliest = expire_at;
 422                                 continue;
 423                         }
 424                 }
 425
 426                 /* The activity count sits at 0 whilst the conn is unused on
 427                  * the list; we reduce that to -1 to make the conn unavailable.
 428                  */
 429                 active = 0;
 430                 if (!atomic_try_cmpxchg(&conn->active, &active, -1))
 431                         continue;
 432                 rxrpc_see_connection(conn, rxrpc_conn_see_reap_service);
 433
 434                 if (rxrpc_conn_is_client(conn))
 435                         BUG();
 436                 else
 437                         rxrpc_unpublish_service_conn(conn);
 438
 439                 list_move_tail(&conn->link, &graveyard);
 440         }
 441         write_unlock(&rxnet->conn_lock);
 442
 443         if (earliest != now + MAX_JIFFY_OFFSET) {
 444                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
 445                 ASSERT(time_after(earliest, now));
 446                 rxrpc_set_service_reap_timer(rxnet, earliest);
 447         }
 448
 449         while (!list_empty(&graveyard)) {
 450                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 451                                   link);
 452                 list_del_init(&conn->link);
 453
 454                 ASSERTCMP(atomic_read(&conn->active), ==, -1);
 455                 rxrpc_put_connection(conn, rxrpc_conn_put_service_reaped);
 456         }
 457
 458         _leave("");
 459 }
 460
 461 /*
 462  * preemptively destroy all the service connection records rather than
 463  * waiting for them to time out
 464  */
 465 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
 466 {
 467         struct rxrpc_connection *conn, *_p;
 468         bool leak = false;
 469
 470         _enter("");
 471
 472         atomic_dec(&rxnet->nr_conns);
 473         rxrpc_destroy_all_client_connections(rxnet);
 474
 475         del_timer_sync(&rxnet->service_conn_reap_timer);
 476         rxrpc_queue_work(&rxnet->service_conn_reaper);
 477         flush_workqueue(rxrpc_workqueue);
 478
 479         write_lock(&rxnet->conn_lock);
 480         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 481                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 482                        conn, refcount_read(&conn->ref));
 483                 leak = true;
 484         }
 485         write_unlock(&rxnet->conn_lock);
 486         BUG_ON(leak);
 487
 488         ASSERT(list_empty(&rxnet->conn_proc_list));
 489
 490         /* We need to wait for the connections to be destroyed by RCU as they
 491          * pin things that we still need to get rid of.
 492          */
 493         wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
 494         _leave("");
 495 }