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