net/rxrpc/conn_object.c

   1 /* RxRPC virtual connection handler, common bits.
   2  *
   3  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/net.h>
  17 #include <linux/skbuff.h>
  18 #include "ar-internal.h"
  19
  20 /*
  21  * Time till a connection expires after last use (in seconds).
  22  */
  23 unsigned int rxrpc_connection_expiry = 10 * 60;
  24
  25 static void rxrpc_connection_reaper(struct work_struct *work);
  26
  27 LIST_HEAD(rxrpc_connections);
  28 LIST_HEAD(rxrpc_connection_proc_list);
  29 DEFINE_RWLOCK(rxrpc_connection_lock);
  30 static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);
  31
  32 static void rxrpc_destroy_connection(struct rcu_head *);
  33
  34 /*
  35  * allocate a new connection
  36  */
  37 struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
  38 {
  39         struct rxrpc_connection *conn;
  40
  41         _enter("");
  42
  43         conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
  44         if (conn) {
  45                 INIT_LIST_HEAD(&conn->cache_link);
  46                 spin_lock_init(&conn->channel_lock);
  47                 INIT_LIST_HEAD(&conn->waiting_calls);
  48                 INIT_WORK(&conn->processor, &rxrpc_process_connection);
  49                 INIT_LIST_HEAD(&conn->proc_link);
  50                 INIT_LIST_HEAD(&conn->link);
  51                 skb_queue_head_init(&conn->rx_queue);
  52                 conn->security = &rxrpc_no_security;
  53                 spin_lock_init(&conn->state_lock);
  54                 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
  55                 conn->size_align = 4;
  56                 conn->idle_timestamp = jiffies;
  57         }
  58
  59         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
  60         return conn;
  61 }
  62
  63 /*
  64  * Look up a connection in the cache by protocol parameters.
  65  *
  66  * If successful, a pointer to the connection is returned, but no ref is taken.
  67  * NULL is returned if there is no match.
  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 {
  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         k.epoch = sp->hdr.epoch;
  86         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
  87
  88         /* We may have to handle mixing IPv4 and IPv6 */
  89         if (srx.transport.family != local->srx.transport.family) {
  90                 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
  91                                     srx.transport.family,
  92                                     local->srx.transport.family);
  93                 goto not_found;
  94         }
  95
  96         k.epoch = sp->hdr.epoch;
  97         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
  98
  99         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED) {
 100                 /* We need to look up service connections by the full protocol
 101                  * parameter set.  We look up the peer first as an intermediate
 102                  * step and then the connection from the peer's tree.
 103                  */
 104                 peer = rxrpc_lookup_peer_rcu(local, &srx);
 105                 if (!peer)
 106                         goto not_found;
 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                 chan->last_service_id = call->service_id;
 178                 if (call->abort_code) {
 179                         chan->last_abort = call->abort_code;
 180                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 181                 } else {
 182                         chan->last_seq = call->rx_hard_ack;
 183                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 184                 }
 185                 /* Sync with rxrpc_conn_retransmit(). */
 186                 smp_wmb();
 187                 chan->last_call = chan->call_id;
 188                 chan->call_id = chan->call_counter;
 189
 190                 rcu_assign_pointer(chan->call, NULL);
 191         }
 192
 193         _leave("");
 194 }
 195
 196 /*
 197  * Disconnect a call and clear any channel it occupies when that call
 198  * terminates.
 199  */
 200 void rxrpc_disconnect_call(struct rxrpc_call *call)
 201 {
 202         struct rxrpc_connection *conn = call->conn;
 203
 204         spin_lock_bh(&conn->params.peer->lock);
 205         hlist_del_init(&call->error_link);
 206         spin_unlock_bh(&conn->params.peer->lock);
 207
 208         if (rxrpc_is_client_call(call))
 209                 return rxrpc_disconnect_client_call(call);
 210
 211         spin_lock(&conn->channel_lock);
 212         __rxrpc_disconnect_call(conn, call);
 213         spin_unlock(&conn->channel_lock);
 214
 215         call->conn = NULL;
 216         conn->idle_timestamp = jiffies;
 217         rxrpc_put_connection(conn);
 218 }
 219
 220 /*
 221  * Kill off a connection.
 222  */
 223 void rxrpc_kill_connection(struct rxrpc_connection *conn)
 224 {
 225         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 226                !rcu_access_pointer(conn->channels[1].call) &&
 227                !rcu_access_pointer(conn->channels[2].call) &&
 228                !rcu_access_pointer(conn->channels[3].call));
 229         ASSERT(list_empty(&conn->cache_link));
 230
 231         write_lock(&rxrpc_connection_lock);
 232         list_del_init(&conn->proc_link);
 233         write_unlock(&rxrpc_connection_lock);
 234
 235         /* Drain the Rx queue.  Note that even though we've unpublished, an
 236          * incoming packet could still be being added to our Rx queue, so we
 237          * will need to drain it again in the RCU cleanup handler.
 238          */
 239         rxrpc_purge_queue(&conn->rx_queue);
 240
 241         /* Leave final destruction to RCU.  The connection processor work item
 242          * must carry a ref on the connection to prevent us getting here whilst
 243          * it is queued or running.
 244          */
 245         call_rcu(&conn->rcu, rxrpc_destroy_connection);
 246 }
 247
 248 /*
 249  * Queue a connection's work processor, getting a ref to pass to the work
 250  * queue.
 251  */
 252 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 253 {
 254         const void *here = __builtin_return_address(0);
 255         int n = __atomic_add_unless(&conn->usage, 1, 0);
 256         if (n == 0)
 257                 return false;
 258         if (rxrpc_queue_work(&conn->processor))
 259                 trace_rxrpc_conn(conn, rxrpc_conn_queued, n + 1, here);
 260         else
 261                 rxrpc_put_connection(conn);
 262         return true;
 263 }
 264
 265 /*
 266  * Note the re-emergence of a connection.
 267  */
 268 void rxrpc_see_connection(struct rxrpc_connection *conn)
 269 {
 270         const void *here = __builtin_return_address(0);
 271         if (conn) {
 272                 int n = atomic_read(&conn->usage);
 273
 274                 trace_rxrpc_conn(conn, rxrpc_conn_seen, n, here);
 275         }
 276 }
 277
 278 /*
 279  * Get a ref on a connection.
 280  */
 281 void rxrpc_get_connection(struct rxrpc_connection *conn)
 282 {
 283         const void *here = __builtin_return_address(0);
 284         int n = atomic_inc_return(&conn->usage);
 285
 286         trace_rxrpc_conn(conn, rxrpc_conn_got, n, here);
 287 }
 288
 289 /*
 290  * Try to get a ref on a connection.
 291  */
 292 struct rxrpc_connection *
 293 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
 294 {
 295         const void *here = __builtin_return_address(0);
 296
 297         if (conn) {
 298                 int n = __atomic_add_unless(&conn->usage, 1, 0);
 299                 if (n > 0)
 300                         trace_rxrpc_conn(conn, rxrpc_conn_got, n + 1, here);
 301                 else
 302                         conn = NULL;
 303         }
 304         return conn;
 305 }
 306
 307 /*
 308  * Release a service connection
 309  */
 310 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
 311 {
 312         const void *here = __builtin_return_address(0);
 313         int n;
 314
 315         n = atomic_dec_return(&conn->usage);
 316         trace_rxrpc_conn(conn, rxrpc_conn_put_service, n, here);
 317         ASSERTCMP(n, >=, 0);
 318         if (n == 0)
 319                 rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 320 }
 321
 322 /*
 323  * destroy a virtual connection
 324  */
 325 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 326 {
 327         struct rxrpc_connection *conn =
 328                 container_of(rcu, struct rxrpc_connection, rcu);
 329
 330         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
 331
 332         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 333
 334         _net("DESTROY CONN %d", conn->debug_id);
 335
 336         rxrpc_purge_queue(&conn->rx_queue);
 337
 338         conn->security->clear(conn);
 339         key_put(conn->params.key);
 340         key_put(conn->server_key);
 341         rxrpc_put_peer(conn->params.peer);
 342         rxrpc_put_local(conn->params.local);
 343
 344         kfree(conn);
 345         _leave("");
 346 }
 347
 348 /*
 349  * reap dead service connections
 350  */
 351 static void rxrpc_connection_reaper(struct work_struct *work)
 352 {
 353         struct rxrpc_connection *conn, *_p;
 354         unsigned long reap_older_than, earliest, idle_timestamp, now;
 355
 356         LIST_HEAD(graveyard);
 357
 358         _enter("");
 359
 360         now = jiffies;
 361         reap_older_than = now - rxrpc_connection_expiry * HZ;
 362         earliest = ULONG_MAX;
 363
 364         write_lock(&rxrpc_connection_lock);
 365         list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
 366                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
 367                 if (likely(atomic_read(&conn->usage) > 1))
 368                         continue;
 369                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 370                         continue;
 371
 372                 idle_timestamp = READ_ONCE(conn->idle_timestamp);
 373                 _debug("reap CONN %d { u=%d,t=%ld }",
 374                        conn->debug_id, atomic_read(&conn->usage),
 375                        (long)reap_older_than - (long)idle_timestamp);
 376
 377                 if (time_after(idle_timestamp, reap_older_than)) {
 378                         if (time_before(idle_timestamp, earliest))
 379                                 earliest = idle_timestamp;
 380                         continue;
 381                 }
 382
 383                 /* The usage count sits at 1 whilst the object is unused on the
 384                  * list; we reduce that to 0 to make the object unavailable.
 385                  */
 386                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 387                         continue;
 388
 389                 if (rxrpc_conn_is_client(conn))
 390                         BUG();
 391                 else
 392                         rxrpc_unpublish_service_conn(conn);
 393
 394                 list_move_tail(&conn->link, &graveyard);
 395         }
 396         write_unlock(&rxrpc_connection_lock);
 397
 398         if (earliest != ULONG_MAX) {
 399                 _debug("reschedule reaper %ld", (long) earliest - now);
 400                 ASSERT(time_after(earliest, now));
 401                 rxrpc_queue_delayed_work(&rxrpc_connection_reap,
 402                                          earliest - now);
 403         }
 404
 405         while (!list_empty(&graveyard)) {
 406                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 407                                   link);
 408                 list_del_init(&conn->link);
 409
 410                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 411                 rxrpc_kill_connection(conn);
 412         }
 413
 414         _leave("");
 415 }
 416
 417 /*
 418  * preemptively destroy all the service connection records rather than
 419  * waiting for them to time out
 420  */
 421 void __exit rxrpc_destroy_all_connections(void)
 422 {
 423         struct rxrpc_connection *conn, *_p;
 424         bool leak = false;
 425
 426         _enter("");
 427
 428         rxrpc_destroy_all_client_connections();
 429
 430         rxrpc_connection_expiry = 0;
 431         cancel_delayed_work(&rxrpc_connection_reap);
 432         rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 433         flush_workqueue(rxrpc_workqueue);
 434
 435         write_lock(&rxrpc_connection_lock);
 436         list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
 437                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 438                        conn, atomic_read(&conn->usage));
 439                 leak = true;
 440         }
 441         write_unlock(&rxrpc_connection_lock);
 442         BUG_ON(leak);
 443
 444         ASSERT(list_empty(&rxrpc_connection_proc_list));
 445
 446         /* Make sure the local and peer records pinned by any dying connections
 447          * are released.
 448          */
 449         rcu_barrier();
 450         rxrpc_destroy_client_conn_ids();
 451
 452         _leave("");
 453 }