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                 spin_lock_init(&conn->channel_lock);
  45                 INIT_LIST_HEAD(&conn->waiting_calls);
  46                 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
  47                 INIT_WORK(&conn->processor, &rxrpc_process_connection);
  48                 INIT_LIST_HEAD(&conn->proc_link);
  49                 INIT_LIST_HEAD(&conn->link);
  50                 skb_queue_head_init(&conn->rx_queue);
  51                 conn->security = &rxrpc_no_security;
  52                 spin_lock_init(&conn->state_lock);
  53                 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
  54                 conn->size_align = 4;
  55                 conn->idle_timestamp = jiffies;
  56         }
  57
  58         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
  59         return conn;
  60 }
  61
  62 /*
  63  * Look up a connection in the cache by protocol parameters.
  64  *
  65  * If successful, a pointer to the connection is returned, but no ref is taken.
  66  * NULL is returned if there is no match.
  67  *
  68  * When searching for a service call, if we find a peer but no connection, we
  69  * return that through *_peer in case we need to create a new service call.
  70  *
  71  * The caller must be holding the RCU read lock.
  72  */
  73 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
  74                                                    struct sk_buff *skb,
  75                                                    struct rxrpc_peer **_peer)
  76 {
  77         struct rxrpc_connection *conn;
  78         struct rxrpc_conn_proto k;
  79         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  80         struct sockaddr_rxrpc srx;
  81         struct rxrpc_peer *peer;
  82
  83         _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
  84
  85         if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
  86                 goto not_found;
  87
  88         if (srx.transport.family != local->srx.transport.family &&
  89             (srx.transport.family == AF_INET &&
  90              local->srx.transport.family != AF_INET6)) {
  91                 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
  92                                     srx.transport.family,
  93                                     local->srx.transport.family);
  94                 goto not_found;
  95         }
  96
  97         k.epoch = sp->hdr.epoch;
  98         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
  99
 100         if (rxrpc_to_server(sp)) {
 101                 /* We need to look up service connections by the full protocol
 102                  * parameter set.  We look up the peer first as an intermediate
 103                  * step and then the connection from the peer's tree.
 104                  */
 105                 peer = rxrpc_lookup_peer_rcu(local, &srx);
 106                 if (!peer)
 107                         goto not_found;
 108                 *_peer = peer;
 109                 conn = rxrpc_find_service_conn_rcu(peer, skb);
 110                 if (!conn || atomic_read(&conn->usage) == 0)
 111                         goto not_found;
 112                 _leave(" = %p", conn);
 113                 return conn;
 114         } else {
 115                 /* Look up client connections by connection ID alone as their
 116                  * IDs are unique for this machine.
 117                  */
 118                 conn = idr_find(&rxrpc_client_conn_ids,
 119                                 sp->hdr.cid >> RXRPC_CIDSHIFT);
 120                 if (!conn || atomic_read(&conn->usage) == 0) {
 121                         _debug("no conn");
 122                         goto not_found;
 123                 }
 124
 125                 if (conn->proto.epoch != k.epoch ||
 126                     conn->params.local != local)
 127                         goto not_found;
 128
 129                 peer = conn->params.peer;
 130                 switch (srx.transport.family) {
 131                 case AF_INET:
 132                         if (peer->srx.transport.sin.sin_port !=
 133                             srx.transport.sin.sin_port ||
 134                             peer->srx.transport.sin.sin_addr.s_addr !=
 135                             srx.transport.sin.sin_addr.s_addr)
 136                                 goto not_found;
 137                         break;
 138 #ifdef CONFIG_AF_RXRPC_IPV6
 139                 case AF_INET6:
 140                         if (peer->srx.transport.sin6.sin6_port !=
 141                             srx.transport.sin6.sin6_port ||
 142                             memcmp(&peer->srx.transport.sin6.sin6_addr,
 143                                    &srx.transport.sin6.sin6_addr,
 144                                    sizeof(struct in6_addr)) != 0)
 145                                 goto not_found;
 146                         break;
 147 #endif
 148                 default:
 149                         BUG();
 150                 }
 151
 152                 _leave(" = %p", conn);
 153                 return conn;
 154         }
 155
 156 not_found:
 157         _leave(" = NULL");
 158         return NULL;
 159 }
 160
 161 /*
 162  * Disconnect a call and clear any channel it occupies when that call
 163  * terminates.  The caller must hold the channel_lock and must release the
 164  * call's ref on the connection.
 165  */
 166 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
 167                              struct rxrpc_call *call)
 168 {
 169         struct rxrpc_channel *chan =
 170                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
 171
 172         _enter("%d,%x", conn->debug_id, call->cid);
 173
 174         if (rcu_access_pointer(chan->call) == call) {
 175                 /* Save the result of the call so that we can repeat it if necessary
 176                  * through the channel, whilst disposing of the actual call record.
 177                  */
 178                 trace_rxrpc_disconnect_call(call);
 179                 switch (call->completion) {
 180                 case RXRPC_CALL_SUCCEEDED:
 181                         chan->last_seq = call->rx_hard_ack;
 182                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 183                         break;
 184                 case RXRPC_CALL_LOCALLY_ABORTED:
 185                         chan->last_abort = call->abort_code;
 186                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 187                         break;
 188                 default:
 189                         chan->last_abort = RX_USER_ABORT;
 190                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 191                         break;
 192                 }
 193
 194                 /* Sync with rxrpc_conn_retransmit(). */
 195                 smp_wmb();
 196                 chan->last_call = chan->call_id;
 197                 chan->call_id = chan->call_counter;
 198
 199                 rcu_assign_pointer(chan->call, NULL);
 200         }
 201
 202         _leave("");
 203 }
 204
 205 /*
 206  * Disconnect a call and clear any channel it occupies when that call
 207  * terminates.
 208  */
 209 void rxrpc_disconnect_call(struct rxrpc_call *call)
 210 {
 211         struct rxrpc_connection *conn = call->conn;
 212
 213         call->peer->cong_cwnd = call->cong_cwnd;
 214
 215         if (!hlist_unhashed(&call->error_link)) {
 216                 spin_lock_bh(&call->peer->lock);
 217                 hlist_del_rcu(&call->error_link);
 218                 spin_unlock_bh(&call->peer->lock);
 219         }
 220
 221         if (rxrpc_is_client_call(call))
 222                 return rxrpc_disconnect_client_call(call);
 223
 224         spin_lock(&conn->channel_lock);
 225         __rxrpc_disconnect_call(conn, call);
 226         spin_unlock(&conn->channel_lock);
 227
 228         set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
 229         conn->idle_timestamp = jiffies;
 230 }
 231
 232 /*
 233  * Kill off a connection.
 234  */
 235 void rxrpc_kill_connection(struct rxrpc_connection *conn)
 236 {
 237         struct rxrpc_net *rxnet = conn->params.local->rxnet;
 238
 239         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 240                !rcu_access_pointer(conn->channels[1].call) &&
 241                !rcu_access_pointer(conn->channels[2].call) &&
 242                !rcu_access_pointer(conn->channels[3].call));
 243         ASSERT(list_empty(&conn->cache_link));
 244
 245         write_lock(&rxnet->conn_lock);
 246         list_del_init(&conn->proc_link);
 247         write_unlock(&rxnet->conn_lock);
 248
 249         /* Drain the Rx queue.  Note that even though we've unpublished, an
 250          * incoming packet could still be being added to our Rx queue, so we
 251          * will need to drain it again in the RCU cleanup handler.
 252          */
 253         rxrpc_purge_queue(&conn->rx_queue);
 254
 255         /* Leave final destruction to RCU.  The connection processor work item
 256          * must carry a ref on the connection to prevent us getting here whilst
 257          * it is queued or running.
 258          */
 259         call_rcu(&conn->rcu, rxrpc_destroy_connection);
 260 }
 261
 262 /*
 263  * Queue a connection's work processor, getting a ref to pass to the work
 264  * queue.
 265  */
 266 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 267 {
 268         const void *here = __builtin_return_address(0);
 269         int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 270         if (n == 0)
 271                 return false;
 272         if (rxrpc_queue_work(&conn->processor))
 273                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, n + 1, here);
 274         else
 275                 rxrpc_put_connection(conn);
 276         return true;
 277 }
 278
 279 /*
 280  * Note the re-emergence of a connection.
 281  */
 282 void rxrpc_see_connection(struct rxrpc_connection *conn)
 283 {
 284         const void *here = __builtin_return_address(0);
 285         if (conn) {
 286                 int n = atomic_read(&conn->usage);
 287
 288                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_seen, n, here);
 289         }
 290 }
 291
 292 /*
 293  * Get a ref on a connection.
 294  */
 295 void rxrpc_get_connection(struct rxrpc_connection *conn)
 296 {
 297         const void *here = __builtin_return_address(0);
 298         int n = atomic_inc_return(&conn->usage);
 299
 300         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n, here);
 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
 311         if (conn) {
 312                 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 313                 if (n > 0)
 314                         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n + 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 n;
 339
 340         n = atomic_dec_return(&conn->usage);
 341         trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, n, here);
 342         ASSERTCMP(n, >=, 0);
 343         if (n == 1)
 344                 rxrpc_set_service_reap_timer(conn->params.local->rxnet,
 345                                              jiffies + rxrpc_connection_expiry);
 346 }
 347
 348 /*
 349  * destroy a virtual connection
 350  */
 351 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 352 {
 353         struct rxrpc_connection *conn =
 354                 container_of(rcu, struct rxrpc_connection, rcu);
 355
 356         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
 357
 358         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 359
 360         _net("DESTROY CONN %d", conn->debug_id);
 361
 362         del_timer_sync(&conn->timer);
 363         rxrpc_purge_queue(&conn->rx_queue);
 364
 365         conn->security->clear(conn);
 366         key_put(conn->params.key);
 367         key_put(conn->server_key);
 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 }