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, rxrpc_conn_queue_timer);
  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, enum rxrpc_conn_trace why)
 264 {
 265         int r;
 266
 267         if (!__refcount_inc_not_zero(&conn->ref, &r))
 268                 return false;
 269         if (rxrpc_queue_work(&conn->processor))
 270                 trace_rxrpc_conn(conn->debug_id, why, r + 1);
 271         else
 272                 rxrpc_put_connection(conn, rxrpc_conn_put_already_queued);
 273         return true;
 274 }
 275
 276 /*
 277  * Note the re-emergence of a connection.
 278  */
 279 void rxrpc_see_connection(struct rxrpc_connection *conn,
 280                           enum rxrpc_conn_trace why)
 281 {
 282         if (conn) {
 283                 int r = refcount_read(&conn->ref);
 284
 285                 trace_rxrpc_conn(conn->debug_id, r, why);
 286         }
 287 }
 288
 289 /*
 290  * Get a ref on a connection.
 291  */
 292 struct rxrpc_connection *rxrpc_get_connection(struct rxrpc_connection *conn,
 293                                               enum rxrpc_conn_trace why)
 294 {
 295         int r;
 296
 297         __refcount_inc(&conn->ref, &r);
 298         trace_rxrpc_conn(conn->debug_id, r + 1, why);
 299         return conn;
 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                            enum rxrpc_conn_trace why)
 308 {
 309         int r;
 310
 311         if (conn) {
 312                 if (__refcount_inc_not_zero(&conn->ref, &r))
 313                         trace_rxrpc_conn(conn->debug_id, r + 1, why);
 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                             enum rxrpc_conn_trace why)
 335 {
 336         unsigned int debug_id = conn->debug_id;
 337         int r;
 338
 339         __refcount_dec(&conn->ref, &r);
 340         trace_rxrpc_conn(debug_id, r - 1, why);
 341         if (r - 1 == 1)
 342                 rxrpc_set_service_reap_timer(conn->local->rxnet,
 343                                              jiffies + rxrpc_connection_expiry);
 344 }
 345
 346 /*
 347  * destroy a virtual connection
 348  */
 349 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 350 {
 351         struct rxrpc_connection *conn =
 352                 container_of(rcu, struct rxrpc_connection, rcu);
 353
 354         _enter("{%d,u=%d}", conn->debug_id, refcount_read(&conn->ref));
 355
 356         trace_rxrpc_conn(conn->debug_id, refcount_read(&conn->ref),
 357                          rxrpc_conn_free);
 358
 359         ASSERTCMP(refcount_read(&conn->ref), ==, 0);
 360
 361         del_timer_sync(&conn->timer);
 362         rxrpc_purge_queue(&conn->rx_queue);
 363
 364         conn->security->clear(conn);
 365         key_put(conn->key);
 366         rxrpc_put_bundle(conn->bundle);
 367         rxrpc_put_peer(conn->peer, rxrpc_peer_put_conn);
 368
 369         if (atomic_dec_and_test(&conn->local->rxnet->nr_conns))
 370                 wake_up_var(&conn->local->rxnet->nr_conns);
 371         rxrpc_put_local(conn->local, rxrpc_local_put_kill_conn);
 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(refcount_read(&conn->ref), >, 0);
 397                 if (likely(refcount_read(&conn->ref) > 1))
 398                         continue;
 399                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 400                         continue;
 401
 402                 if (rxnet->live && !conn->local->dead) {
 403                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
 404                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
 405                         if (conn->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, refcount_read(&conn->ref),
 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 (!refcount_dec_if_one(&conn->ref))
 423                         continue;
 424                 rxrpc_see_connection(conn, rxrpc_conn_see_reap_service);
 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(refcount_read(&conn->ref), ==, 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, refcount_read(&conn->ref));
 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 }