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 || atomic_read(&conn->usage) == 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 || atomic_read(&conn->usage) == 0) {
 118                         _debug("no conn");
 119                         goto not_found;
 120                 }
 121
 122                 if (conn->proto.epoch != k.epoch ||
 123                     conn->params.local != local)
 124                         goto not_found;
 125
 126                 peer = conn->params.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_hard_ack;
 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_USER_ABORT;
 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_cwnd = call->cong_cwnd;
 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->params.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 n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 267         if (n == 0)
 268                 return false;
 269         if (rxrpc_queue_work(&conn->processor))
 270                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, n + 1, here);
 271         else
 272                 rxrpc_put_connection(conn);
 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 {
 281         const void *here = __builtin_return_address(0);
 282         if (conn) {
 283                 int n = atomic_read(&conn->usage);
 284
 285                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_seen, n, here);
 286         }
 287 }
 288
 289 /*
 290  * Get a ref on a connection.
 291  */
 292 struct rxrpc_connection *rxrpc_get_connection(struct rxrpc_connection *conn)
 293 {
 294         const void *here = __builtin_return_address(0);
 295         int n = atomic_inc_return(&conn->usage);
 296
 297         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n, here);
 298         return conn;
 299 }
 300
 301 /*
 302  * Try to get a ref on a connection.
 303  */
 304 struct rxrpc_connection *
 305 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
 306 {
 307         const void *here = __builtin_return_address(0);
 308
 309         if (conn) {
 310                 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 311                 if (n > 0)
 312                         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n + 1, here);
 313                 else
 314                         conn = NULL;
 315         }
 316         return conn;
 317 }
 318
 319 /*
 320  * Set the service connection reap timer.
 321  */
 322 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
 323                                          unsigned long reap_at)
 324 {
 325         if (rxnet->live)
 326                 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
 327 }
 328
 329 /*
 330  * Release a service connection
 331  */
 332 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
 333 {
 334         const void *here = __builtin_return_address(0);
 335         unsigned int debug_id = conn->debug_id;
 336         int n;
 337
 338         n = atomic_dec_return(&conn->usage);
 339         trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, n, here);
 340         ASSERTCMP(n, >=, 0);
 341         if (n == 1)
 342                 rxrpc_set_service_reap_timer(conn->params.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, atomic_read(&conn->usage));
 355
 356         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 357
 358         _net("DESTROY CONN %d", conn->debug_id);
 359
 360         del_timer_sync(&conn->timer);
 361         rxrpc_purge_queue(&conn->rx_queue);
 362
 363         conn->security->clear(conn);
 364         key_put(conn->params.key);
 365         rxrpc_put_bundle(conn->bundle);
 366         rxrpc_put_peer(conn->params.peer);
 367
 368         if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
 369                 wake_up_var(&conn->params.local->rxnet->nr_conns);
 370         rxrpc_put_local(conn->params.local);
 371
 372         kfree(conn);
 373         _leave("");
 374 }
 375
 376 /*
 377  * reap dead service connections
 378  */
 379 void rxrpc_service_connection_reaper(struct work_struct *work)
 380 {
 381         struct rxrpc_connection *conn, *_p;
 382         struct rxrpc_net *rxnet =
 383                 container_of(work, struct rxrpc_net, service_conn_reaper);
 384         unsigned long expire_at, earliest, idle_timestamp, now;
 385
 386         LIST_HEAD(graveyard);
 387
 388         _enter("");
 389
 390         now = jiffies;
 391         earliest = now + MAX_JIFFY_OFFSET;
 392
 393         write_lock(&rxnet->conn_lock);
 394         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 395                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
 396                 if (likely(atomic_read(&conn->usage) > 1))
 397                         continue;
 398                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 399                         continue;
 400
 401                 if (rxnet->live && !conn->params.local->dead) {
 402                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
 403                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
 404                         if (conn->params.local->service_closed)
 405                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
 406
 407                         _debug("reap CONN %d { u=%d,t=%ld }",
 408                                conn->debug_id, atomic_read(&conn->usage),
 409                                (long)expire_at - (long)now);
 410
 411                         if (time_before(now, expire_at)) {
 412                                 if (time_before(expire_at, earliest))
 413                                         earliest = expire_at;
 414                                 continue;
 415                         }
 416                 }
 417
 418                 /* The usage count sits at 1 whilst the object is unused on the
 419                  * list; we reduce that to 0 to make the object unavailable.
 420                  */
 421                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 422                         continue;
 423                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_reap_service, 0, NULL);
 424
 425                 if (rxrpc_conn_is_client(conn))
 426                         BUG();
 427                 else
 428                         rxrpc_unpublish_service_conn(conn);
 429
 430                 list_move_tail(&conn->link, &graveyard);
 431         }
 432         write_unlock(&rxnet->conn_lock);
 433
 434         if (earliest != now + MAX_JIFFY_OFFSET) {
 435                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
 436                 ASSERT(time_after(earliest, now));
 437                 rxrpc_set_service_reap_timer(rxnet, earliest);
 438         }
 439
 440         while (!list_empty(&graveyard)) {
 441                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 442                                   link);
 443                 list_del_init(&conn->link);
 444
 445                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 446                 rxrpc_kill_connection(conn);
 447         }
 448
 449         _leave("");
 450 }
 451
 452 /*
 453  * preemptively destroy all the service connection records rather than
 454  * waiting for them to time out
 455  */
 456 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
 457 {
 458         struct rxrpc_connection *conn, *_p;
 459         bool leak = false;
 460
 461         _enter("");
 462
 463         atomic_dec(&rxnet->nr_conns);
 464         rxrpc_destroy_all_client_connections(rxnet);
 465
 466         del_timer_sync(&rxnet->service_conn_reap_timer);
 467         rxrpc_queue_work(&rxnet->service_conn_reaper);
 468         flush_workqueue(rxrpc_workqueue);
 469
 470         write_lock(&rxnet->conn_lock);
 471         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 472                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 473                        conn, atomic_read(&conn->usage));
 474                 leak = true;
 475         }
 476         write_unlock(&rxnet->conn_lock);
 477         BUG_ON(leak);
 478
 479         ASSERT(list_empty(&rxnet->conn_proc_list));
 480
 481         /* We need to wait for the connections to be destroyed by RCU as they
 482          * pin things that we still need to get rid of.
 483          */
 484         wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
 485         _leave("");
 486 }