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