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->size_align = 4;
  53                 conn->idle_timestamp = jiffies;
  54         }
  55
  56         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
  57         return conn;
  58 }
  59
  60 /*
  61  * Look up a connection in the cache by protocol parameters.
  62  *
  63  * If successful, a pointer to the connection is returned, but no ref is taken.
  64  * NULL is returned if there is no match.
  65  *
  66  * When searching for a service call, if we find a peer but no connection, we
  67  * return that through *_peer in case we need to create a new service call.
  68  *
  69  * The caller must be holding the RCU read lock.
  70  */
  71 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
  72                                                    struct sk_buff *skb,
  73                                                    struct rxrpc_peer **_peer)
  74 {
  75         struct rxrpc_connection *conn;
  76         struct rxrpc_conn_proto k;
  77         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  78         struct sockaddr_rxrpc srx;
  79         struct rxrpc_peer *peer;
  80
  81         _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
  82
  83         if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
  84                 goto not_found;
  85
  86         if (srx.transport.family != local->srx.transport.family &&
  87             (srx.transport.family == AF_INET &&
  88              local->srx.transport.family != AF_INET6)) {
  89                 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
  90                                     srx.transport.family,
  91                                     local->srx.transport.family);
  92                 goto not_found;
  93         }
  94
  95         k.epoch = sp->hdr.epoch;
  96         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
  97
  98         if (rxrpc_to_server(sp)) {
  99                 /* We need to look up service connections by the full protocol
 100                  * parameter set.  We look up the peer first as an intermediate
 101                  * step and then the connection from the peer's tree.
 102                  */
 103                 peer = rxrpc_lookup_peer_rcu(local, &srx);
 104                 if (!peer)
 105                         goto not_found;
 106                 *_peer = peer;
 107                 conn = rxrpc_find_service_conn_rcu(peer, skb);
 108                 if (!conn || atomic_read(&conn->usage) == 0)
 109                         goto not_found;
 110                 _leave(" = %p", conn);
 111                 return conn;
 112         } else {
 113                 /* Look up client connections by connection ID alone as their
 114                  * IDs are unique for this machine.
 115                  */
 116                 conn = idr_find(&rxrpc_client_conn_ids,
 117                                 sp->hdr.cid >> RXRPC_CIDSHIFT);
 118                 if (!conn || atomic_read(&conn->usage) == 0) {
 119                         _debug("no conn");
 120                         goto not_found;
 121                 }
 122
 123                 if (conn->proto.epoch != k.epoch ||
 124                     conn->params.local != local)
 125                         goto not_found;
 126
 127                 peer = conn->params.peer;
 128                 switch (srx.transport.family) {
 129                 case AF_INET:
 130                         if (peer->srx.transport.sin.sin_port !=
 131                             srx.transport.sin.sin_port ||
 132                             peer->srx.transport.sin.sin_addr.s_addr !=
 133                             srx.transport.sin.sin_addr.s_addr)
 134                                 goto not_found;
 135                         break;
 136 #ifdef CONFIG_AF_RXRPC_IPV6
 137                 case AF_INET6:
 138                         if (peer->srx.transport.sin6.sin6_port !=
 139                             srx.transport.sin6.sin6_port ||
 140                             memcmp(&peer->srx.transport.sin6.sin6_addr,
 141                                    &srx.transport.sin6.sin6_addr,
 142                                    sizeof(struct in6_addr)) != 0)
 143                                 goto not_found;
 144                         break;
 145 #endif
 146                 default:
 147                         BUG();
 148                 }
 149
 150                 _leave(" = %p", conn);
 151                 return conn;
 152         }
 153
 154 not_found:
 155         _leave(" = NULL");
 156         return NULL;
 157 }
 158
 159 /*
 160  * Disconnect a call and clear any channel it occupies when that call
 161  * terminates.  The caller must hold the channel_lock and must release the
 162  * call's ref on the connection.
 163  */
 164 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
 165                              struct rxrpc_call *call)
 166 {
 167         struct rxrpc_channel *chan =
 168                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
 169
 170         _enter("%d,%x", conn->debug_id, call->cid);
 171
 172         if (rcu_access_pointer(chan->call) == call) {
 173                 /* Save the result of the call so that we can repeat it if necessary
 174                  * through the channel, whilst disposing of the actual call record.
 175                  */
 176                 trace_rxrpc_disconnect_call(call);
 177                 switch (call->completion) {
 178                 case RXRPC_CALL_SUCCEEDED:
 179                         chan->last_seq = call->rx_hard_ack;
 180                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 181                         break;
 182                 case RXRPC_CALL_LOCALLY_ABORTED:
 183                         chan->last_abort = call->abort_code;
 184                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 185                         break;
 186                 default:
 187                         chan->last_abort = RX_USER_ABORT;
 188                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 189                         break;
 190                 }
 191
 192                 /* Sync with rxrpc_conn_retransmit(). */
 193                 smp_wmb();
 194                 chan->last_call = chan->call_id;
 195                 chan->call_id = chan->call_counter;
 196
 197                 rcu_assign_pointer(chan->call, NULL);
 198         }
 199
 200         _leave("");
 201 }
 202
 203 /*
 204  * Disconnect a call and clear any channel it occupies when that call
 205  * terminates.
 206  */
 207 void rxrpc_disconnect_call(struct rxrpc_call *call)
 208 {
 209         struct rxrpc_connection *conn = call->conn;
 210
 211         call->peer->cong_cwnd = call->cong_cwnd;
 212
 213         if (!hlist_unhashed(&call->error_link)) {
 214                 spin_lock_bh(&call->peer->lock);
 215                 hlist_del_rcu(&call->error_link);
 216                 spin_unlock_bh(&call->peer->lock);
 217         }
 218
 219         if (rxrpc_is_client_call(call))
 220                 return rxrpc_disconnect_client_call(conn->bundle, call);
 221
 222         spin_lock(&conn->bundle->channel_lock);
 223         __rxrpc_disconnect_call(conn, call);
 224         spin_unlock(&conn->bundle->channel_lock);
 225
 226         set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
 227         conn->idle_timestamp = jiffies;
 228 }
 229
 230 /*
 231  * Kill off a connection.
 232  */
 233 void rxrpc_kill_connection(struct rxrpc_connection *conn)
 234 {
 235         struct rxrpc_net *rxnet = conn->params.local->rxnet;
 236
 237         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 238                !rcu_access_pointer(conn->channels[1].call) &&
 239                !rcu_access_pointer(conn->channels[2].call) &&
 240                !rcu_access_pointer(conn->channels[3].call));
 241         ASSERT(list_empty(&conn->cache_link));
 242
 243         write_lock(&rxnet->conn_lock);
 244         list_del_init(&conn->proc_link);
 245         write_unlock(&rxnet->conn_lock);
 246
 247         /* Drain the Rx queue.  Note that even though we've unpublished, an
 248          * incoming packet could still be being added to our Rx queue, so we
 249          * will need to drain it again in the RCU cleanup handler.
 250          */
 251         rxrpc_purge_queue(&conn->rx_queue);
 252
 253         /* Leave final destruction to RCU.  The connection processor work item
 254          * must carry a ref on the connection to prevent us getting here whilst
 255          * it is queued or running.
 256          */
 257         call_rcu(&conn->rcu, rxrpc_destroy_connection);
 258 }
 259
 260 /*
 261  * Queue a connection's work processor, getting a ref to pass to the work
 262  * queue.
 263  */
 264 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 265 {
 266         const void *here = __builtin_return_address(0);
 267         int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 268         if (n == 0)
 269                 return false;
 270         if (rxrpc_queue_work(&conn->processor))
 271                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, n + 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 = atomic_read(&conn->usage);
 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 n = atomic_inc_return(&conn->usage);
 297
 298         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n, here);
 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 {
 308         const void *here = __builtin_return_address(0);
 309
 310         if (conn) {
 311                 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 312                 if (n > 0)
 313                         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n + 1, here);
 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 {
 335         const void *here = __builtin_return_address(0);
 336         unsigned int debug_id = conn->debug_id;
 337         int n;
 338
 339         n = atomic_dec_return(&conn->usage);
 340         trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, n, here);
 341         ASSERTCMP(n, >=, 0);
 342         if (n == 1)
 343                 rxrpc_set_service_reap_timer(conn->params.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, atomic_read(&conn->usage));
 356
 357         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 358
 359         _net("DESTROY CONN %d", conn->debug_id);
 360
 361         del_timer_sync(&conn->timer);
 362         rxrpc_purge_queue(&conn->rx_queue);
 363
 364         conn->security->clear(conn);
 365         key_put(conn->params.key);
 366         key_put(conn->server_key);
 367         rxrpc_put_bundle(conn->bundle);
 368         rxrpc_put_peer(conn->params.peer);
 369
 370         if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
 371                 wake_up_var(&conn->params.local->rxnet->nr_conns);
 372         rxrpc_put_local(conn->params.local);
 373
 374         kfree(conn);
 375         _leave("");
 376 }
 377
 378 /*
 379  * reap dead service connections
 380  */
 381 void rxrpc_service_connection_reaper(struct work_struct *work)
 382 {
 383         struct rxrpc_connection *conn, *_p;
 384         struct rxrpc_net *rxnet =
 385                 container_of(work, struct rxrpc_net, service_conn_reaper);
 386         unsigned long expire_at, earliest, idle_timestamp, now;
 387
 388         LIST_HEAD(graveyard);
 389
 390         _enter("");
 391
 392         now = jiffies;
 393         earliest = now + MAX_JIFFY_OFFSET;
 394
 395         write_lock(&rxnet->conn_lock);
 396         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 397                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
 398                 if (likely(atomic_read(&conn->usage) > 1))
 399                         continue;
 400                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 401                         continue;
 402
 403                 if (rxnet->live && !conn->params.local->dead) {
 404                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
 405                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
 406                         if (conn->params.local->service_closed)
 407                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
 408
 409                         _debug("reap CONN %d { u=%d,t=%ld }",
 410                                conn->debug_id, atomic_read(&conn->usage),
 411                                (long)expire_at - (long)now);
 412
 413                         if (time_before(now, expire_at)) {
 414                                 if (time_before(expire_at, earliest))
 415                                         earliest = expire_at;
 416                                 continue;
 417                         }
 418                 }
 419
 420                 /* The usage count sits at 1 whilst the object is unused on the
 421                  * list; we reduce that to 0 to make the object unavailable.
 422                  */
 423                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 424                         continue;
 425                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_reap_service, 0, NULL);
 426
 427                 if (rxrpc_conn_is_client(conn))
 428                         BUG();
 429                 else
 430                         rxrpc_unpublish_service_conn(conn);
 431
 432                 list_move_tail(&conn->link, &graveyard);
 433         }
 434         write_unlock(&rxnet->conn_lock);
 435
 436         if (earliest != now + MAX_JIFFY_OFFSET) {
 437                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
 438                 ASSERT(time_after(earliest, now));
 439                 rxrpc_set_service_reap_timer(rxnet, earliest);
 440         }
 441
 442         while (!list_empty(&graveyard)) {
 443                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 444                                   link);
 445                 list_del_init(&conn->link);
 446
 447                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 448                 rxrpc_kill_connection(conn);
 449         }
 450
 451         _leave("");
 452 }
 453
 454 /*
 455  * preemptively destroy all the service connection records rather than
 456  * waiting for them to time out
 457  */
 458 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
 459 {
 460         struct rxrpc_connection *conn, *_p;
 461         bool leak = false;
 462
 463         _enter("");
 464
 465         atomic_dec(&rxnet->nr_conns);
 466         rxrpc_destroy_all_client_connections(rxnet);
 467
 468         del_timer_sync(&rxnet->service_conn_reap_timer);
 469         rxrpc_queue_work(&rxnet->service_conn_reaper);
 470         flush_workqueue(rxrpc_workqueue);
 471
 472         write_lock(&rxnet->conn_lock);
 473         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 474                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 475                        conn, atomic_read(&conn->usage));
 476                 leak = true;
 477         }
 478         write_unlock(&rxnet->conn_lock);
 479         BUG_ON(leak);
 480
 481         ASSERT(list_empty(&rxnet->conn_proc_list));
 482
 483         /* We need to wait for the connections to be destroyed by RCU as they
 484          * pin things that we still need to get rid of.
 485          */
 486         wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
 487         _leave("");
 488 }