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