net/rxrpc/conn_object.c

   1 /* RxRPC virtual connection handler, common bits.
   2  *
   3  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/net.h>
  17 #include <linux/skbuff.h>
  18 #include "ar-internal.h"
  19
  20 /*
  21  * Time till a connection expires after last use (in seconds).
  22  */
  23 unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
  24 unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
  25
  26 static void rxrpc_destroy_connection(struct rcu_head *);
  27
  28 static void rxrpc_connection_timer(struct timer_list *timer)
  29 {
  30         struct rxrpc_connection *conn =
  31                 container_of(timer, struct rxrpc_connection, timer);
  32
  33         rxrpc_queue_conn(conn);
  34 }
  35
  36 /*
  37  * allocate a new connection
  38  */
  39 struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
  40 {
  41         struct rxrpc_connection *conn;
  42
  43         _enter("");
  44
  45         conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
  46         if (conn) {
  47                 INIT_LIST_HEAD(&conn->cache_link);
  48                 spin_lock_init(&conn->channel_lock);
  49                 INIT_LIST_HEAD(&conn->waiting_calls);
  50                 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
  51                 INIT_WORK(&conn->processor, &rxrpc_process_connection);
  52                 INIT_LIST_HEAD(&conn->proc_link);
  53                 INIT_LIST_HEAD(&conn->link);
  54                 skb_queue_head_init(&conn->rx_queue);
  55                 conn->security = &rxrpc_no_security;
  56                 spin_lock_init(&conn->state_lock);
  57                 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
  58                 conn->size_align = 4;
  59                 conn->idle_timestamp = jiffies;
  60         }
  61
  62         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
  63         return conn;
  64 }
  65
  66 /*
  67  * Look up a connection in the cache by protocol parameters.
  68  *
  69  * If successful, a pointer to the connection is returned, but no ref is taken.
  70  * NULL is returned if there is no match.
  71  *
  72  * When searching for a service call, if we find a peer but no connection, we
  73  * return that through *_peer in case we need to create a new service call.
  74  *
  75  * The caller must be holding the RCU read lock.
  76  */
  77 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
  78                                                    struct sk_buff *skb,
  79                                                    struct rxrpc_peer **_peer)
  80 {
  81         struct rxrpc_connection *conn;
  82         struct rxrpc_conn_proto k;
  83         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  84         struct sockaddr_rxrpc srx;
  85         struct rxrpc_peer *peer;
  86
  87         _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
  88
  89         if (rxrpc_extract_addr_from_skb(local, &srx, skb) < 0)
  90                 goto not_found;
  91
  92         /* We may have to handle mixing IPv4 and IPv6 */
  93         if (srx.transport.family != local->srx.transport.family) {
  94                 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
  95                                     srx.transport.family,
  96                                     local->srx.transport.family);
  97                 goto not_found;
  98         }
  99
 100         k.epoch = sp->hdr.epoch;
 101         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
 102
 103         if (rxrpc_to_server(sp)) {
 104                 /* We need to look up service connections by the full protocol
 105                  * parameter set.  We look up the peer first as an intermediate
 106                  * step and then the connection from the peer's tree.
 107                  */
 108                 peer = rxrpc_lookup_peer_rcu(local, &srx);
 109                 if (!peer)
 110                         goto not_found;
 111                 *_peer = peer;
 112                 conn = rxrpc_find_service_conn_rcu(peer, skb);
 113                 if (!conn || atomic_read(&conn->usage) == 0)
 114                         goto not_found;
 115                 _leave(" = %p", conn);
 116                 return conn;
 117         } else {
 118                 /* Look up client connections by connection ID alone as their
 119                  * IDs are unique for this machine.
 120                  */
 121                 conn = idr_find(&rxrpc_client_conn_ids,
 122                                 sp->hdr.cid >> RXRPC_CIDSHIFT);
 123                 if (!conn || atomic_read(&conn->usage) == 0) {
 124                         _debug("no conn");
 125                         goto not_found;
 126                 }
 127
 128                 if (conn->proto.epoch != k.epoch ||
 129                     conn->params.local != local)
 130                         goto not_found;
 131
 132                 peer = conn->params.peer;
 133                 switch (srx.transport.family) {
 134                 case AF_INET:
 135                         if (peer->srx.transport.sin.sin_port !=
 136                             srx.transport.sin.sin_port ||
 137                             peer->srx.transport.sin.sin_addr.s_addr !=
 138                             srx.transport.sin.sin_addr.s_addr)
 139                                 goto not_found;
 140                         break;
 141 #ifdef CONFIG_AF_RXRPC_IPV6
 142                 case AF_INET6:
 143                         if (peer->srx.transport.sin6.sin6_port !=
 144                             srx.transport.sin6.sin6_port ||
 145                             memcmp(&peer->srx.transport.sin6.sin6_addr,
 146                                    &srx.transport.sin6.sin6_addr,
 147                                    sizeof(struct in6_addr)) != 0)
 148                                 goto not_found;
 149                         break;
 150 #endif
 151                 default:
 152                         BUG();
 153                 }
 154
 155                 _leave(" = %p", conn);
 156                 return conn;
 157         }
 158
 159 not_found:
 160         _leave(" = NULL");
 161         return NULL;
 162 }
 163
 164 /*
 165  * Disconnect a call and clear any channel it occupies when that call
 166  * terminates.  The caller must hold the channel_lock and must release the
 167  * call's ref on the connection.
 168  */
 169 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
 170                              struct rxrpc_call *call)
 171 {
 172         struct rxrpc_channel *chan =
 173                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
 174
 175         _enter("%d,%x", conn->debug_id, call->cid);
 176
 177         if (rcu_access_pointer(chan->call) == call) {
 178                 /* Save the result of the call so that we can repeat it if necessary
 179                  * through the channel, whilst disposing of the actual call record.
 180                  */
 181                 trace_rxrpc_disconnect_call(call);
 182                 switch (call->completion) {
 183                 case RXRPC_CALL_SUCCEEDED:
 184                         chan->last_seq = call->rx_hard_ack;
 185                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 186                         break;
 187                 case RXRPC_CALL_LOCALLY_ABORTED:
 188                         chan->last_abort = call->abort_code;
 189                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 190                         break;
 191                 default:
 192                         chan->last_abort = RX_USER_ABORT;
 193                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 194                         break;
 195                 }
 196
 197                 /* Sync with rxrpc_conn_retransmit(). */
 198                 smp_wmb();
 199                 chan->last_call = chan->call_id;
 200                 chan->call_id = chan->call_counter;
 201
 202                 rcu_assign_pointer(chan->call, NULL);
 203         }
 204
 205         _leave("");
 206 }
 207
 208 /*
 209  * Disconnect a call and clear any channel it occupies when that call
 210  * terminates.
 211  */
 212 void rxrpc_disconnect_call(struct rxrpc_call *call)
 213 {
 214         struct rxrpc_connection *conn = call->conn;
 215
 216         call->peer->cong_cwnd = call->cong_cwnd;
 217
 218         spin_lock_bh(&conn->params.peer->lock);
 219         hlist_del_rcu(&call->error_link);
 220         spin_unlock_bh(&conn->params.peer->lock);
 221
 222         if (rxrpc_is_client_call(call))
 223                 return rxrpc_disconnect_client_call(call);
 224
 225         spin_lock(&conn->channel_lock);
 226         __rxrpc_disconnect_call(conn, call);
 227         spin_unlock(&conn->channel_lock);
 228
 229         call->conn = NULL;
 230         conn->idle_timestamp = jiffies;
 231         rxrpc_put_connection(conn);
 232 }
 233
 234 /*
 235  * Kill off a connection.
 236  */
 237 void rxrpc_kill_connection(struct rxrpc_connection *conn)
 238 {
 239         struct rxrpc_net *rxnet = conn->params.local->rxnet;
 240
 241         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 242                !rcu_access_pointer(conn->channels[1].call) &&
 243                !rcu_access_pointer(conn->channels[2].call) &&
 244                !rcu_access_pointer(conn->channels[3].call));
 245         ASSERT(list_empty(&conn->cache_link));
 246
 247         write_lock(&rxnet->conn_lock);
 248         list_del_init(&conn->proc_link);
 249         write_unlock(&rxnet->conn_lock);
 250
 251         /* Drain the Rx queue.  Note that even though we've unpublished, an
 252          * incoming packet could still be being added to our Rx queue, so we
 253          * will need to drain it again in the RCU cleanup handler.
 254          */
 255         rxrpc_purge_queue(&conn->rx_queue);
 256
 257         /* Leave final destruction to RCU.  The connection processor work item
 258          * must carry a ref on the connection to prevent us getting here whilst
 259          * it is queued or running.
 260          */
 261         call_rcu(&conn->rcu, rxrpc_destroy_connection);
 262 }
 263
 264 /*
 265  * Queue a connection's work processor, getting a ref to pass to the work
 266  * queue.
 267  */
 268 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 269 {
 270         const void *here = __builtin_return_address(0);
 271         int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 272         if (n == 0)
 273                 return false;
 274         if (rxrpc_queue_work(&conn->processor))
 275                 trace_rxrpc_conn(conn, rxrpc_conn_queued, n + 1, here);
 276         else
 277                 rxrpc_put_connection(conn);
 278         return true;
 279 }
 280
 281 /*
 282  * Note the re-emergence of a connection.
 283  */
 284 void rxrpc_see_connection(struct rxrpc_connection *conn)
 285 {
 286         const void *here = __builtin_return_address(0);
 287         if (conn) {
 288                 int n = atomic_read(&conn->usage);
 289
 290                 trace_rxrpc_conn(conn, rxrpc_conn_seen, n, here);
 291         }
 292 }
 293
 294 /*
 295  * Get a ref on a connection.
 296  */
 297 void rxrpc_get_connection(struct rxrpc_connection *conn)
 298 {
 299         const void *here = __builtin_return_address(0);
 300         int n = atomic_inc_return(&conn->usage);
 301
 302         trace_rxrpc_conn(conn, rxrpc_conn_got, n, here);
 303 }
 304
 305 /*
 306  * Try to get a ref on a connection.
 307  */
 308 struct rxrpc_connection *
 309 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
 310 {
 311         const void *here = __builtin_return_address(0);
 312
 313         if (conn) {
 314                 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 315                 if (n > 0)
 316                         trace_rxrpc_conn(conn, rxrpc_conn_got, n + 1, here);
 317                 else
 318                         conn = NULL;
 319         }
 320         return conn;
 321 }
 322
 323 /*
 324  * Set the service connection reap timer.
 325  */
 326 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
 327                                          unsigned long reap_at)
 328 {
 329         if (rxnet->live)
 330                 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
 331 }
 332
 333 /*
 334  * Release a service connection
 335  */
 336 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
 337 {
 338         const void *here = __builtin_return_address(0);
 339         int n;
 340
 341         n = atomic_dec_return(&conn->usage);
 342         trace_rxrpc_conn(conn, rxrpc_conn_put_service, n, here);
 343         ASSERTCMP(n, >=, 0);
 344         if (n == 1)
 345                 rxrpc_set_service_reap_timer(conn->params.local->rxnet,
 346                                              jiffies + rxrpc_connection_expiry);
 347 }
 348
 349 /*
 350  * destroy a virtual connection
 351  */
 352 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 353 {
 354         struct rxrpc_connection *conn =
 355                 container_of(rcu, struct rxrpc_connection, rcu);
 356
 357         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
 358
 359         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 360
 361         _net("DESTROY CONN %d", conn->debug_id);
 362
 363         del_timer_sync(&conn->timer);
 364         rxrpc_purge_queue(&conn->rx_queue);
 365
 366         conn->security->clear(conn);
 367         key_put(conn->params.key);
 368         key_put(conn->server_key);
 369         rxrpc_put_peer(conn->params.peer);
 370
 371         if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
 372                 wake_up_var(&conn->params.local->rxnet->nr_conns);
 373         rxrpc_put_local(conn->params.local);
 374
 375         kfree(conn);
 376         _leave("");
 377 }
 378
 379 /*
 380  * reap dead service connections
 381  */
 382 void rxrpc_service_connection_reaper(struct work_struct *work)
 383 {
 384         struct rxrpc_connection *conn, *_p;
 385         struct rxrpc_net *rxnet =
 386                 container_of(work, struct rxrpc_net, service_conn_reaper);
 387         unsigned long expire_at, earliest, idle_timestamp, now;
 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->usage), >, 0);
 399                 if (likely(atomic_read(&conn->usage) > 1))
 400                         continue;
 401                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 402                         continue;
 403
 404                 if (rxnet->live) {
 405                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
 406                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
 407                         if (conn->params.local->service_closed)
 408                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
 409
 410                         _debug("reap CONN %d { u=%d,t=%ld }",
 411                                conn->debug_id, atomic_read(&conn->usage),
 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 usage count sits at 1 whilst the object is unused on the
 422                  * list; we reduce that to 0 to make the object unavailable.
 423                  */
 424                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 425                         continue;
 426                 trace_rxrpc_conn(conn, rxrpc_conn_reap_service, 0, NULL);
 427
 428                 if (rxrpc_conn_is_client(conn))
 429                         BUG();
 430                 else
 431                         rxrpc_unpublish_service_conn(conn);
 432
 433                 list_move_tail(&conn->link, &graveyard);
 434         }
 435         write_unlock(&rxnet->conn_lock);
 436
 437         if (earliest != now + MAX_JIFFY_OFFSET) {
 438                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
 439                 ASSERT(time_after(earliest, now));
 440                 rxrpc_set_service_reap_timer(rxnet, earliest);
 441         }
 442
 443         while (!list_empty(&graveyard)) {
 444                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 445                                   link);
 446                 list_del_init(&conn->link);
 447
 448                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 449                 rxrpc_kill_connection(conn);
 450         }
 451
 452         _leave("");
 453 }
 454
 455 /*
 456  * preemptively destroy all the service connection records rather than
 457  * waiting for them to time out
 458  */
 459 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
 460 {
 461         struct rxrpc_connection *conn, *_p;
 462         bool leak = false;
 463
 464         _enter("");
 465
 466         atomic_dec(&rxnet->nr_conns);
 467         rxrpc_destroy_all_client_connections(rxnet);
 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, atomic_read(&conn->usage));
 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 }