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                 chan->last_service_id = call->service_id;
 177                 if (call->abort_code) {
 178                         chan->last_abort = call->abort_code;
 179                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 180                 } else {
 181                         chan->last_seq = call->rx_hard_ack;
 182                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 183                 }
 184                 /* Sync with rxrpc_conn_retransmit(). */
 185                 smp_wmb();
 186                 chan->last_call = chan->call_id;
 187                 chan->call_id = chan->call_counter;
 188
 189                 rcu_assign_pointer(chan->call, NULL);
 190         }
 191
 192         _leave("");
 193 }
 194
 195 /*
 196  * Disconnect a call and clear any channel it occupies when that call
 197  * terminates.
 198  */
 199 void rxrpc_disconnect_call(struct rxrpc_call *call)
 200 {
 201         struct rxrpc_connection *conn = call->conn;
 202
 203         spin_lock_bh(&conn->params.peer->lock);
 204         hlist_del_init(&call->error_link);
 205         spin_unlock_bh(&conn->params.peer->lock);
 206
 207         if (rxrpc_is_client_call(call))
 208                 return rxrpc_disconnect_client_call(call);
 209
 210         spin_lock(&conn->channel_lock);
 211         __rxrpc_disconnect_call(conn, call);
 212         spin_unlock(&conn->channel_lock);
 213
 214         call->conn = NULL;
 215         conn->idle_timestamp = jiffies;
 216         rxrpc_put_connection(conn);
 217 }
 218
 219 /*
 220  * Kill off a connection.
 221  */
 222 void rxrpc_kill_connection(struct rxrpc_connection *conn)
 223 {
 224         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 225                !rcu_access_pointer(conn->channels[1].call) &&
 226                !rcu_access_pointer(conn->channels[2].call) &&
 227                !rcu_access_pointer(conn->channels[3].call));
 228         ASSERT(list_empty(&conn->cache_link));
 229
 230         write_lock(&rxrpc_connection_lock);
 231         list_del_init(&conn->proc_link);
 232         write_unlock(&rxrpc_connection_lock);
 233
 234         /* Drain the Rx queue.  Note that even though we've unpublished, an
 235          * incoming packet could still be being added to our Rx queue, so we
 236          * will need to drain it again in the RCU cleanup handler.
 237          */
 238         rxrpc_purge_queue(&conn->rx_queue);
 239
 240         /* Leave final destruction to RCU.  The connection processor work item
 241          * must carry a ref on the connection to prevent us getting here whilst
 242          * it is queued or running.
 243          */
 244         call_rcu(&conn->rcu, rxrpc_destroy_connection);
 245 }
 246
 247 /*
 248  * Queue a connection's work processor, getting a ref to pass to the work
 249  * queue.
 250  */
 251 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 252 {
 253         const void *here = __builtin_return_address(0);
 254         int n = __atomic_add_unless(&conn->usage, 1, 0);
 255         if (n == 0)
 256                 return false;
 257         if (rxrpc_queue_work(&conn->processor))
 258                 trace_rxrpc_conn(conn, rxrpc_conn_queued, n + 1, here);
 259         else
 260                 rxrpc_put_connection(conn);
 261         return true;
 262 }
 263
 264 /*
 265  * Note the re-emergence of a connection.
 266  */
 267 void rxrpc_see_connection(struct rxrpc_connection *conn)
 268 {
 269         const void *here = __builtin_return_address(0);
 270         if (conn) {
 271                 int n = atomic_read(&conn->usage);
 272
 273                 trace_rxrpc_conn(conn, rxrpc_conn_seen, n, here);
 274         }
 275 }
 276
 277 /*
 278  * Get a ref on a connection.
 279  */
 280 void rxrpc_get_connection(struct rxrpc_connection *conn)
 281 {
 282         const void *here = __builtin_return_address(0);
 283         int n = atomic_inc_return(&conn->usage);
 284
 285         trace_rxrpc_conn(conn, rxrpc_conn_got, n, here);
 286 }
 287
 288 /*
 289  * Try to get a ref on a connection.
 290  */
 291 struct rxrpc_connection *
 292 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
 293 {
 294         const void *here = __builtin_return_address(0);
 295
 296         if (conn) {
 297                 int n = __atomic_add_unless(&conn->usage, 1, 0);
 298                 if (n > 0)
 299                         trace_rxrpc_conn(conn, rxrpc_conn_got, n + 1, here);
 300                 else
 301                         conn = NULL;
 302         }
 303         return conn;
 304 }
 305
 306 /*
 307  * Release a service connection
 308  */
 309 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
 310 {
 311         const void *here = __builtin_return_address(0);
 312         int n;
 313
 314         n = atomic_dec_return(&conn->usage);
 315         trace_rxrpc_conn(conn, rxrpc_conn_put_service, n, here);
 316         ASSERTCMP(n, >=, 0);
 317         if (n == 0)
 318                 rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 319 }
 320
 321 /*
 322  * destroy a virtual connection
 323  */
 324 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 325 {
 326         struct rxrpc_connection *conn =
 327                 container_of(rcu, struct rxrpc_connection, rcu);
 328
 329         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
 330
 331         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 332
 333         _net("DESTROY CONN %d", conn->debug_id);
 334
 335         rxrpc_purge_queue(&conn->rx_queue);
 336
 337         conn->security->clear(conn);
 338         key_put(conn->params.key);
 339         key_put(conn->server_key);
 340         rxrpc_put_peer(conn->params.peer);
 341         rxrpc_put_local(conn->params.local);
 342
 343         kfree(conn);
 344         _leave("");
 345 }
 346
 347 /*
 348  * reap dead service connections
 349  */
 350 static void rxrpc_connection_reaper(struct work_struct *work)
 351 {
 352         struct rxrpc_connection *conn, *_p;
 353         unsigned long reap_older_than, earliest, idle_timestamp, now;
 354
 355         LIST_HEAD(graveyard);
 356
 357         _enter("");
 358
 359         now = jiffies;
 360         reap_older_than = now - rxrpc_connection_expiry * HZ;
 361         earliest = ULONG_MAX;
 362
 363         write_lock(&rxrpc_connection_lock);
 364         list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
 365                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
 366                 if (likely(atomic_read(&conn->usage) > 1))
 367                         continue;
 368                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 369                         continue;
 370
 371                 idle_timestamp = READ_ONCE(conn->idle_timestamp);
 372                 _debug("reap CONN %d { u=%d,t=%ld }",
 373                        conn->debug_id, atomic_read(&conn->usage),
 374                        (long)reap_older_than - (long)idle_timestamp);
 375
 376                 if (time_after(idle_timestamp, reap_older_than)) {
 377                         if (time_before(idle_timestamp, earliest))
 378                                 earliest = idle_timestamp;
 379                         continue;
 380                 }
 381
 382                 /* The usage count sits at 1 whilst the object is unused on the
 383                  * list; we reduce that to 0 to make the object unavailable.
 384                  */
 385                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 386                         continue;
 387
 388                 if (rxrpc_conn_is_client(conn))
 389                         BUG();
 390                 else
 391                         rxrpc_unpublish_service_conn(conn);
 392
 393                 list_move_tail(&conn->link, &graveyard);
 394         }
 395         write_unlock(&rxrpc_connection_lock);
 396
 397         if (earliest != ULONG_MAX) {
 398                 _debug("reschedule reaper %ld", (long) earliest - now);
 399                 ASSERT(time_after(earliest, now));
 400                 rxrpc_queue_delayed_work(&rxrpc_connection_reap,
 401                                          earliest - now);
 402         }
 403
 404         while (!list_empty(&graveyard)) {
 405                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 406                                   link);
 407                 list_del_init(&conn->link);
 408
 409                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 410                 rxrpc_kill_connection(conn);
 411         }
 412
 413         _leave("");
 414 }
 415
 416 /*
 417  * preemptively destroy all the service connection records rather than
 418  * waiting for them to time out
 419  */
 420 void __exit rxrpc_destroy_all_connections(void)
 421 {
 422         struct rxrpc_connection *conn, *_p;
 423         bool leak = false;
 424
 425         _enter("");
 426
 427         rxrpc_destroy_all_client_connections();
 428
 429         rxrpc_connection_expiry = 0;
 430         cancel_delayed_work(&rxrpc_connection_reap);
 431         rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 432         flush_workqueue(rxrpc_workqueue);
 433
 434         write_lock(&rxrpc_connection_lock);
 435         list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
 436                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 437                        conn, atomic_read(&conn->usage));
 438                 leak = true;
 439         }
 440         write_unlock(&rxrpc_connection_lock);
 441         BUG_ON(leak);
 442
 443         ASSERT(list_empty(&rxrpc_connection_proc_list));
 444
 445         /* Make sure the local and peer records pinned by any dying connections
 446          * are released.
 447          */
 448         rcu_barrier();
 449         rxrpc_destroy_client_conn_ids();
 450
 451         _leave("");
 452 }