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         if (!hlist_unhashed(&call->error_link)) {
 219                 spin_lock_bh(&call->peer->lock);
 220                 hlist_del_rcu(&call->error_link);
 221                 spin_unlock_bh(&call->peer->lock);
 222         }
 223
 224         if (rxrpc_is_client_call(call))
 225                 return rxrpc_disconnect_client_call(call);
 226
 227         spin_lock(&conn->channel_lock);
 228         __rxrpc_disconnect_call(conn, call);
 229         spin_unlock(&conn->channel_lock);
 230
 231         set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
 232         conn->idle_timestamp = jiffies;
 233 }
 234
 235 /*
 236  * Kill off a connection.
 237  */
 238 void rxrpc_kill_connection(struct rxrpc_connection *conn)
 239 {
 240         struct rxrpc_net *rxnet = conn->params.local->rxnet;
 241
 242         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 243                !rcu_access_pointer(conn->channels[1].call) &&
 244                !rcu_access_pointer(conn->channels[2].call) &&
 245                !rcu_access_pointer(conn->channels[3].call));
 246         ASSERT(list_empty(&conn->cache_link));
 247
 248         write_lock(&rxnet->conn_lock);
 249         list_del_init(&conn->proc_link);
 250         write_unlock(&rxnet->conn_lock);
 251
 252         /* Drain the Rx queue.  Note that even though we've unpublished, an
 253          * incoming packet could still be being added to our Rx queue, so we
 254          * will need to drain it again in the RCU cleanup handler.
 255          */
 256         rxrpc_purge_queue(&conn->rx_queue);
 257
 258         /* Leave final destruction to RCU.  The connection processor work item
 259          * must carry a ref on the connection to prevent us getting here whilst
 260          * it is queued or running.
 261          */
 262         call_rcu(&conn->rcu, rxrpc_destroy_connection);
 263 }
 264
 265 /*
 266  * Queue a connection's work processor, getting a ref to pass to the work
 267  * queue.
 268  */
 269 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 270 {
 271         const void *here = __builtin_return_address(0);
 272         int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 273         if (n == 0)
 274                 return false;
 275         if (rxrpc_queue_work(&conn->processor))
 276                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, n + 1, here);
 277         else
 278                 rxrpc_put_connection(conn);
 279         return true;
 280 }
 281
 282 /*
 283  * Note the re-emergence of a connection.
 284  */
 285 void rxrpc_see_connection(struct rxrpc_connection *conn)
 286 {
 287         const void *here = __builtin_return_address(0);
 288         if (conn) {
 289                 int n = atomic_read(&conn->usage);
 290
 291                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_seen, n, here);
 292         }
 293 }
 294
 295 /*
 296  * Get a ref on a connection.
 297  */
 298 void rxrpc_get_connection(struct rxrpc_connection *conn)
 299 {
 300         const void *here = __builtin_return_address(0);
 301         int n = atomic_inc_return(&conn->usage);
 302
 303         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n, here);
 304 }
 305
 306 /*
 307  * Try to get a ref on a connection.
 308  */
 309 struct rxrpc_connection *
 310 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
 311 {
 312         const void *here = __builtin_return_address(0);
 313
 314         if (conn) {
 315                 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 316                 if (n > 0)
 317                         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n + 1, here);
 318                 else
 319                         conn = NULL;
 320         }
 321         return conn;
 322 }
 323
 324 /*
 325  * Set the service connection reap timer.
 326  */
 327 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
 328                                          unsigned long reap_at)
 329 {
 330         if (rxnet->live)
 331                 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
 332 }
 333
 334 /*
 335  * Release a service connection
 336  */
 337 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
 338 {
 339         const void *here = __builtin_return_address(0);
 340         unsigned int debug_id = conn->debug_id;
 341         int n;
 342
 343         n = atomic_dec_return(&conn->usage);
 344         trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, n, here);
 345         ASSERTCMP(n, >=, 0);
 346         if (n == 1)
 347                 rxrpc_set_service_reap_timer(conn->params.local->rxnet,
 348                                              jiffies + rxrpc_connection_expiry);
 349 }
 350
 351 /*
 352  * destroy a virtual connection
 353  */
 354 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 355 {
 356         struct rxrpc_connection *conn =
 357                 container_of(rcu, struct rxrpc_connection, rcu);
 358
 359         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
 360
 361         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 362
 363         _net("DESTROY CONN %d", conn->debug_id);
 364
 365         del_timer_sync(&conn->timer);
 366         rxrpc_purge_queue(&conn->rx_queue);
 367
 368         conn->security->clear(conn);
 369         key_put(conn->params.key);
 370         key_put(conn->server_key);
 371         rxrpc_put_peer(conn->params.peer);
 372
 373         if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
 374                 wake_up_var(&conn->params.local->rxnet->nr_conns);
 375         rxrpc_put_local(conn->params.local);
 376
 377         kfree(conn);
 378         _leave("");
 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
 391         LIST_HEAD(graveyard);
 392
 393         _enter("");
 394
 395         now = jiffies;
 396         earliest = now + MAX_JIFFY_OFFSET;
 397
 398         write_lock(&rxnet->conn_lock);
 399         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 400                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
 401                 if (likely(atomic_read(&conn->usage) > 1))
 402                         continue;
 403                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 404                         continue;
 405
 406                 if (rxnet->live && !conn->params.local->dead) {
 407                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
 408                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
 409                         if (conn->params.local->service_closed)
 410                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
 411
 412                         _debug("reap CONN %d { u=%d,t=%ld }",
 413                                conn->debug_id, atomic_read(&conn->usage),
 414                                (long)expire_at - (long)now);
 415
 416                         if (time_before(now, expire_at)) {
 417                                 if (time_before(expire_at, earliest))
 418                                         earliest = expire_at;
 419                                 continue;
 420                         }
 421                 }
 422
 423                 /* The usage count sits at 1 whilst the object is unused on the
 424                  * list; we reduce that to 0 to make the object unavailable.
 425                  */
 426                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 427                         continue;
 428                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_reap_service, 0, NULL);
 429
 430                 if (rxrpc_conn_is_client(conn))
 431                         BUG();
 432                 else
 433                         rxrpc_unpublish_service_conn(conn);
 434
 435                 list_move_tail(&conn->link, &graveyard);
 436         }
 437         write_unlock(&rxnet->conn_lock);
 438
 439         if (earliest != now + MAX_JIFFY_OFFSET) {
 440                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
 441                 ASSERT(time_after(earliest, now));
 442                 rxrpc_set_service_reap_timer(rxnet, earliest);
 443         }
 444
 445         while (!list_empty(&graveyard)) {
 446                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 447                                   link);
 448                 list_del_init(&conn->link);
 449
 450                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 451                 rxrpc_kill_connection(conn);
 452         }
 453
 454         _leave("");
 455 }
 456
 457 /*
 458  * preemptively destroy all the service connection records rather than
 459  * waiting for them to time out
 460  */
 461 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
 462 {
 463         struct rxrpc_connection *conn, *_p;
 464         bool leak = false;
 465
 466         _enter("");
 467
 468         atomic_dec(&rxnet->nr_conns);
 469         rxrpc_destroy_all_client_connections(rxnet);
 470
 471         del_timer_sync(&rxnet->service_conn_reap_timer);
 472         rxrpc_queue_work(&rxnet->service_conn_reaper);
 473         flush_workqueue(rxrpc_workqueue);
 474
 475         write_lock(&rxnet->conn_lock);
 476         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 477                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 478                        conn, atomic_read(&conn->usage));
 479                 leak = true;
 480         }
 481         write_unlock(&rxnet->conn_lock);
 482         BUG_ON(leak);
 483
 484         ASSERT(list_empty(&rxnet->conn_proc_list));
 485
 486         /* We need to wait for the connections to be destroyed by RCU as they
 487          * pin things that we still need to get rid of.
 488          */
 489         wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
 490         _leave("");
 491 }