git.rot13.org Git - linux/blob - 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(&srx, skb) < 0)
  90                 goto not_found;
  91
  92         if (srx.transport.family != local->srx.transport.family &&
  93             (srx.transport.family == AF_INET &&
  94              local->srx.transport.family != AF_INET6)) {
  95                 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
  96                                     srx.transport.family,
  97                                     local->srx.transport.family);
  98                 goto not_found;
  99         }
 100
 101         k.epoch = sp->hdr.epoch;
 102         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
 103
 104         if (rxrpc_to_server(sp)) {
 105                 /* We need to look up service connections by the full protocol
 106                  * parameter set.  We look up the peer first as an intermediate
 107                  * step and then the connection from the peer's tree.
 108                  */
 109                 peer = rxrpc_lookup_peer_rcu(local, &srx);
 110                 if (!peer)
 111                         goto not_found;
 112                 *_peer = peer;
 113                 conn = rxrpc_find_service_conn_rcu(peer, skb);
 114                 if (!conn || atomic_read(&conn->usage) == 0)
 115                         goto not_found;
 116                 _leave(" = %p", conn);
 117                 return conn;
 118         } else {
 119                 /* Look up client connections by connection ID alone as their
 120                  * IDs are unique for this machine.
 121                  */
 122                 conn = idr_find(&rxrpc_client_conn_ids,
 123                                 sp->hdr.cid >> RXRPC_CIDSHIFT);
 124                 if (!conn || atomic_read(&conn->usage) == 0) {
 125                         _debug("no conn");
 126                         goto not_found;
 127                 }
 128
 129                 if (conn->proto.epoch != k.epoch ||
 130                     conn->params.local != local)
 131                         goto not_found;
 132
 133                 peer = conn->params.peer;
 134                 switch (srx.transport.family) {
 135                 case AF_INET:
 136                         if (peer->srx.transport.sin.sin_port !=
 137                             srx.transport.sin.sin_port ||
 138                             peer->srx.transport.sin.sin_addr.s_addr !=
 139                             srx.transport.sin.sin_addr.s_addr)
 140                                 goto not_found;
 141                         break;
 142 #ifdef CONFIG_AF_RXRPC_IPV6
 143                 case AF_INET6:
 144                         if (peer->srx.transport.sin6.sin6_port !=
 145                             srx.transport.sin6.sin6_port ||
 146                             memcmp(&peer->srx.transport.sin6.sin6_addr,
 147                                    &srx.transport.sin6.sin6_addr,
 148                                    sizeof(struct in6_addr)) != 0)
 149                                 goto not_found;
 150                         break;
 151 #endif
 152                 default:
 153                         BUG();
 154                 }
 155
 156                 _leave(" = %p", conn);
 157                 return conn;
 158         }
 159
 160 not_found:
 161         _leave(" = NULL");
 162         return NULL;
 163 }
 164
 165 /*
 166  * Disconnect a call and clear any channel it occupies when that call
 167  * terminates.  The caller must hold the channel_lock and must release the
 168  * call's ref on the connection.
 169  */
 170 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
 171                              struct rxrpc_call *call)
 172 {
 173         struct rxrpc_channel *chan =
 174                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
 175
 176         _enter("%d,%x", conn->debug_id, call->cid);
 177
 178         if (rcu_access_pointer(chan->call) == call) {
 179                 /* Save the result of the call so that we can repeat it if necessary
 180                  * through the channel, whilst disposing of the actual call record.
 181                  */
 182                 trace_rxrpc_disconnect_call(call);
 183                 switch (call->completion) {
 184                 case RXRPC_CALL_SUCCEEDED:
 185                         chan->last_seq = call->rx_hard_ack;
 186                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 187                         break;
 188                 case RXRPC_CALL_LOCALLY_ABORTED:
 189                         chan->last_abort = call->abort_code;
 190                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 191                         break;
 192                 default:
 193                         chan->last_abort = RX_USER_ABORT;
 194                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 195                         break;
 196                 }
 197
 198                 /* Sync with rxrpc_conn_retransmit(). */
 199                 smp_wmb();
 200                 chan->last_call = chan->call_id;
 201                 chan->call_id = chan->call_counter;
 202
 203                 rcu_assign_pointer(chan->call, NULL);
 204         }
 205
 206         _leave("");
 207 }
 208
 209 /*
 210  * Disconnect a call and clear any channel it occupies when that call
 211  * terminates.
 212  */
 213 void rxrpc_disconnect_call(struct rxrpc_call *call)
 214 {
 215         struct rxrpc_connection *conn = call->conn;
 216
 217         call->peer->cong_cwnd = call->cong_cwnd;
 218
 219         spin_lock_bh(&conn->params.peer->lock);
 220         hlist_del_rcu(&call->error_link);
 221         spin_unlock_bh(&conn->params.peer->lock);
 222
 223         if (rxrpc_is_client_call(call))
 224                 return rxrpc_disconnect_client_call(call);
 225
 226         spin_lock(&conn->channel_lock);
 227         __rxrpc_disconnect_call(conn, call);
 228         spin_unlock(&conn->channel_lock);
 229
 230         call->conn = NULL;
 231         conn->idle_timestamp = jiffies;
 232         rxrpc_put_connection(conn);
 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, 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, 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, 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, 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         int n;
 341
 342         n = atomic_dec_return(&conn->usage);
 343         trace_rxrpc_conn(conn, rxrpc_conn_put_service, n, here);
 344         ASSERTCMP(n, >=, 0);
 345         if (n == 1)
 346                 rxrpc_set_service_reap_timer(conn->params.local->rxnet,
 347                                              jiffies + rxrpc_connection_expiry);
 348 }
 349
 350 /*
 351  * destroy a virtual connection
 352  */
 353 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 354 {
 355         struct rxrpc_connection *conn =
 356                 container_of(rcu, struct rxrpc_connection, rcu);
 357
 358         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
 359
 360         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 361
 362         _net("DESTROY CONN %d", conn->debug_id);
 363
 364         del_timer_sync(&conn->timer);
 365         rxrpc_purge_queue(&conn->rx_queue);
 366
 367         conn->security->clear(conn);
 368         key_put(conn->params.key);
 369         key_put(conn->server_key);
 370         rxrpc_put_peer(conn->params.peer);
 371
 372         if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
 373                 wake_up_var(&conn->params.local->rxnet->nr_conns);
 374         rxrpc_put_local(conn->params.local);
 375
 376         kfree(conn);
 377         _leave("");
 378 }
 379
 380 /*
 381  * reap dead service connections
 382  */
 383 void rxrpc_service_connection_reaper(struct work_struct *work)
 384 {
 385         struct rxrpc_connection *conn, *_p;
 386         struct rxrpc_net *rxnet =
 387                 container_of(work, struct rxrpc_net, service_conn_reaper);
 388         unsigned long expire_at, earliest, idle_timestamp, now;
 389
 390         LIST_HEAD(graveyard);
 391
 392         _enter("");
 393
 394         now = jiffies;
 395         earliest = now + MAX_JIFFY_OFFSET;
 396
 397         write_lock(&rxnet->conn_lock);
 398         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 399                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
 400                 if (likely(atomic_read(&conn->usage) > 1))
 401                         continue;
 402                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 403                         continue;
 404
 405                 if (rxnet->live) {
 406                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
 407                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
 408                         if (conn->params.local->service_closed)
 409                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
 410
 411                         _debug("reap CONN %d { u=%d,t=%ld }",
 412                                conn->debug_id, atomic_read(&conn->usage),
 413                                (long)expire_at - (long)now);
 414
 415                         if (time_before(now, expire_at)) {
 416                                 if (time_before(expire_at, earliest))
 417                                         earliest = expire_at;
 418                                 continue;
 419                         }
 420                 }
 421
 422                 /* The usage count sits at 1 whilst the object is unused on the
 423                  * list; we reduce that to 0 to make the object unavailable.
 424                  */
 425                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 426                         continue;
 427                 trace_rxrpc_conn(conn, rxrpc_conn_reap_service, 0, NULL);
 428
 429                 if (rxrpc_conn_is_client(conn))
 430                         BUG();
 431                 else
 432                         rxrpc_unpublish_service_conn(conn);
 433
 434                 list_move_tail(&conn->link, &graveyard);
 435         }
 436         write_unlock(&rxnet->conn_lock);
 437
 438         if (earliest != now + MAX_JIFFY_OFFSET) {
 439                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
 440                 ASSERT(time_after(earliest, now));
 441                 rxrpc_set_service_reap_timer(rxnet, earliest);
 442         }
 443
 444         while (!list_empty(&graveyard)) {
 445                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 446                                   link);
 447                 list_del_init(&conn->link);
 448
 449                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 450                 rxrpc_kill_connection(conn);
 451         }
 452
 453         _leave("");
 454 }
 455
 456 /*
 457  * preemptively destroy all the service connection records rather than
 458  * waiting for them to time out
 459  */
 460 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
 461 {
 462         struct rxrpc_connection *conn, *_p;
 463         bool leak = false;
 464
 465         _enter("");
 466
 467         atomic_dec(&rxnet->nr_conns);
 468         rxrpc_destroy_all_client_connections(rxnet);
 469
 470         del_timer_sync(&rxnet->service_conn_reap_timer);
 471         rxrpc_queue_work(&rxnet->service_conn_reaper);
 472         flush_workqueue(rxrpc_workqueue);
 473
 474         write_lock(&rxnet->conn_lock);
 475         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 476                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 477                        conn, atomic_read(&conn->usage));
 478                 leak = true;
 479         }
 480         write_unlock(&rxnet->conn_lock);
 481         BUG_ON(leak);
 482
 483         ASSERT(list_empty(&rxnet->conn_proc_list));
 484
 485         /* We need to wait for the connections to be destroyed by RCU as they
 486          * pin things that we still need to get rid of.
 487          */
 488         wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
 489         _leave("");
 490 }