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