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