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 __read_mostly rxrpc_connection_expiry = 10 * 60;
  24 unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
  25
  26 static void rxrpc_destroy_connection(struct rcu_head *);
  27
  28 /*
  29  * allocate a new connection
  30  */
  31 struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
  32 {
  33         struct rxrpc_connection *conn;
  34
  35         _enter("");
  36
  37         conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
  38         if (conn) {
  39                 INIT_LIST_HEAD(&conn->cache_link);
  40                 spin_lock_init(&conn->channel_lock);
  41                 INIT_LIST_HEAD(&conn->waiting_calls);
  42                 INIT_WORK(&conn->processor, &rxrpc_process_connection);
  43                 INIT_LIST_HEAD(&conn->proc_link);
  44                 INIT_LIST_HEAD(&conn->link);
  45                 skb_queue_head_init(&conn->rx_queue);
  46                 conn->security = &rxrpc_no_security;
  47                 spin_lock_init(&conn->state_lock);
  48                 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
  49                 conn->size_align = 4;
  50                 conn->idle_timestamp = jiffies;
  51         }
  52
  53         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
  54         return conn;
  55 }
  56
  57 /*
  58  * Look up a connection in the cache by protocol parameters.
  59  *
  60  * If successful, a pointer to the connection is returned, but no ref is taken.
  61  * NULL is returned if there is no match.
  62  *
  63  * The caller must be holding the RCU read lock.
  64  */
  65 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
  66                                                    struct sk_buff *skb)
  67 {
  68         struct rxrpc_connection *conn;
  69         struct rxrpc_conn_proto k;
  70         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  71         struct sockaddr_rxrpc srx;
  72         struct rxrpc_peer *peer;
  73
  74         _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
  75
  76         if (rxrpc_extract_addr_from_skb(local, &srx, skb) < 0)
  77                 goto not_found;
  78
  79         k.epoch = sp->hdr.epoch;
  80         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
  81
  82         /* We may have to handle mixing IPv4 and IPv6 */
  83         if (srx.transport.family != local->srx.transport.family) {
  84                 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
  85                                     srx.transport.family,
  86                                     local->srx.transport.family);
  87                 goto not_found;
  88         }
  89
  90         k.epoch = sp->hdr.epoch;
  91         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
  92
  93         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED) {
  94                 /* We need to look up service connections by the full protocol
  95                  * parameter set.  We look up the peer first as an intermediate
  96                  * step and then the connection from the peer's tree.
  97                  */
  98                 peer = rxrpc_lookup_peer_rcu(local, &srx);
  99                 if (!peer)
 100                         goto not_found;
 101                 conn = rxrpc_find_service_conn_rcu(peer, skb);
 102                 if (!conn || atomic_read(&conn->usage) == 0)
 103                         goto not_found;
 104                 _leave(" = %p", conn);
 105                 return conn;
 106         } else {
 107                 /* Look up client connections by connection ID alone as their
 108                  * IDs are unique for this machine.
 109                  */
 110                 conn = idr_find(&rxrpc_client_conn_ids,
 111                                 sp->hdr.cid >> RXRPC_CIDSHIFT);
 112                 if (!conn || atomic_read(&conn->usage) == 0) {
 113                         _debug("no conn");
 114                         goto not_found;
 115                 }
 116
 117                 if (conn->proto.epoch != k.epoch ||
 118                     conn->params.local != local)
 119                         goto not_found;
 120
 121                 peer = conn->params.peer;
 122                 switch (srx.transport.family) {
 123                 case AF_INET:
 124                         if (peer->srx.transport.sin.sin_port !=
 125                             srx.transport.sin.sin_port ||
 126                             peer->srx.transport.sin.sin_addr.s_addr !=
 127                             srx.transport.sin.sin_addr.s_addr)
 128                                 goto not_found;
 129                         break;
 130 #ifdef CONFIG_AF_RXRPC_IPV6
 131                 case AF_INET6:
 132                         if (peer->srx.transport.sin6.sin6_port !=
 133                             srx.transport.sin6.sin6_port ||
 134                             memcmp(&peer->srx.transport.sin6.sin6_addr,
 135                                    &srx.transport.sin6.sin6_addr,
 136                                    sizeof(struct in6_addr)) != 0)
 137                                 goto not_found;
 138                         break;
 139 #endif
 140                 default:
 141                         BUG();
 142                 }
 143
 144                 _leave(" = %p", conn);
 145                 return conn;
 146         }
 147
 148 not_found:
 149         _leave(" = NULL");
 150         return NULL;
 151 }
 152
 153 /*
 154  * Disconnect a call and clear any channel it occupies when that call
 155  * terminates.  The caller must hold the channel_lock and must release the
 156  * call's ref on the connection.
 157  */
 158 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
 159                              struct rxrpc_call *call)
 160 {
 161         struct rxrpc_channel *chan =
 162                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
 163
 164         _enter("%d,%x", conn->debug_id, call->cid);
 165
 166         if (rcu_access_pointer(chan->call) == call) {
 167                 /* Save the result of the call so that we can repeat it if necessary
 168                  * through the channel, whilst disposing of the actual call record.
 169                  */
 170                 trace_rxrpc_disconnect_call(call);
 171                 if (call->abort_code) {
 172                         chan->last_abort = call->abort_code;
 173                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 174                 } else {
 175                         chan->last_seq = call->rx_hard_ack;
 176                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 177                 }
 178                 /* Sync with rxrpc_conn_retransmit(). */
 179                 smp_wmb();
 180                 chan->last_call = chan->call_id;
 181                 chan->call_id = chan->call_counter;
 182
 183                 rcu_assign_pointer(chan->call, NULL);
 184         }
 185
 186         _leave("");
 187 }
 188
 189 /*
 190  * Disconnect a call and clear any channel it occupies when that call
 191  * terminates.
 192  */
 193 void rxrpc_disconnect_call(struct rxrpc_call *call)
 194 {
 195         struct rxrpc_connection *conn = call->conn;
 196
 197         call->peer->cong_cwnd = call->cong_cwnd;
 198
 199         if (!hlist_unhashed(&call->error_link)) {
 200                 spin_lock_bh(&conn->params.peer->lock);
 201                 hlist_del_init(&call->error_link);
 202                 spin_unlock_bh(&conn->params.peer->lock);
 203         }
 204
 205         if (rxrpc_is_client_call(call))
 206                 return rxrpc_disconnect_client_call(call);
 207
 208         spin_lock(&conn->channel_lock);
 209         __rxrpc_disconnect_call(conn, call);
 210         spin_unlock(&conn->channel_lock);
 211
 212         set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
 213         conn->idle_timestamp = jiffies;
 214 }
 215
 216 /*
 217  * Kill off a connection.
 218  */
 219 void rxrpc_kill_connection(struct rxrpc_connection *conn)
 220 {
 221         struct rxrpc_net *rxnet = conn->params.local->rxnet;
 222
 223         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 224                !rcu_access_pointer(conn->channels[1].call) &&
 225                !rcu_access_pointer(conn->channels[2].call) &&
 226                !rcu_access_pointer(conn->channels[3].call));
 227         ASSERT(list_empty(&conn->cache_link));
 228
 229         write_lock(&rxnet->conn_lock);
 230         list_del_init(&conn->proc_link);
 231         write_unlock(&rxnet->conn_lock);
 232
 233         /* Drain the Rx queue.  Note that even though we've unpublished, an
 234          * incoming packet could still be being added to our Rx queue, so we
 235          * will need to drain it again in the RCU cleanup handler.
 236          */
 237         rxrpc_purge_queue(&conn->rx_queue);
 238
 239         /* Leave final destruction to RCU.  The connection processor work item
 240          * must carry a ref on the connection to prevent us getting here whilst
 241          * it is queued or running.
 242          */
 243         call_rcu(&conn->rcu, rxrpc_destroy_connection);
 244 }
 245
 246 /*
 247  * Queue a connection's work processor, getting a ref to pass to the work
 248  * queue.
 249  */
 250 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 251 {
 252         const void *here = __builtin_return_address(0);
 253         int n = __atomic_add_unless(&conn->usage, 1, 0);
 254         if (n == 0)
 255                 return false;
 256         if (rxrpc_queue_work(&conn->processor))
 257                 trace_rxrpc_conn(conn, rxrpc_conn_queued, n + 1, here);
 258         else
 259                 rxrpc_put_connection(conn);
 260         return true;
 261 }
 262
 263 /*
 264  * Note the re-emergence of a connection.
 265  */
 266 void rxrpc_see_connection(struct rxrpc_connection *conn)
 267 {
 268         const void *here = __builtin_return_address(0);
 269         if (conn) {
 270                 int n = atomic_read(&conn->usage);
 271
 272                 trace_rxrpc_conn(conn, rxrpc_conn_seen, n, here);
 273         }
 274 }
 275
 276 /*
 277  * Get a ref on a connection.
 278  */
 279 void rxrpc_get_connection(struct rxrpc_connection *conn)
 280 {
 281         const void *here = __builtin_return_address(0);
 282         int n = atomic_inc_return(&conn->usage);
 283
 284         trace_rxrpc_conn(conn, rxrpc_conn_got, n, here);
 285 }
 286
 287 /*
 288  * Try to get a ref on a connection.
 289  */
 290 struct rxrpc_connection *
 291 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
 292 {
 293         const void *here = __builtin_return_address(0);
 294
 295         if (conn) {
 296                 int n = __atomic_add_unless(&conn->usage, 1, 0);
 297                 if (n > 0)
 298                         trace_rxrpc_conn(conn, rxrpc_conn_got, n + 1, here);
 299                 else
 300                         conn = NULL;
 301         }
 302         return conn;
 303 }
 304
 305 /*
 306  * Release a service connection
 307  */
 308 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
 309 {
 310         struct rxrpc_net *rxnet;
 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 == 1) {
 318                 rxnet = conn->params.local->rxnet;
 319                 rxrpc_queue_delayed_work(&rxnet->service_conn_reaper, 0);
 320         }
 321 }
 322
 323 /*
 324  * destroy a virtual connection
 325  */
 326 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 327 {
 328         struct rxrpc_connection *conn =
 329                 container_of(rcu, struct rxrpc_connection, rcu);
 330
 331         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
 332
 333         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 334
 335         _net("DESTROY CONN %d", conn->debug_id);
 336
 337         rxrpc_purge_queue(&conn->rx_queue);
 338
 339         conn->security->clear(conn);
 340         key_put(conn->params.key);
 341         key_put(conn->server_key);
 342         rxrpc_put_peer(conn->params.peer);
 343         rxrpc_put_local(conn->params.local);
 344
 345         kfree(conn);
 346         _leave("");
 347 }
 348
 349 /*
 350  * reap dead service connections
 351  */
 352 void rxrpc_service_connection_reaper(struct work_struct *work)
 353 {
 354         struct rxrpc_connection *conn, *_p;
 355         struct rxrpc_net *rxnet =
 356                 container_of(to_delayed_work(work),
 357                              struct rxrpc_net, service_conn_reaper);
 358         unsigned long expire_at, earliest, idle_timestamp, now;
 359
 360         LIST_HEAD(graveyard);
 361
 362         _enter("");
 363
 364         now = jiffies;
 365         earliest = now + MAX_JIFFY_OFFSET;
 366
 367         write_lock(&rxnet->conn_lock);
 368         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 369                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
 370                 if (likely(atomic_read(&conn->usage) > 1))
 371                         continue;
 372                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 373                         continue;
 374
 375                 if (rxnet->live) {
 376                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
 377                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
 378                         if (conn->params.local->service_closed)
 379                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
 380
 381                         _debug("reap CONN %d { u=%d,t=%ld }",
 382                                conn->debug_id, atomic_read(&conn->usage),
 383                                (long)expire_at - (long)now);
 384
 385                         if (time_before(now, expire_at)) {
 386                                 if (time_before(expire_at, earliest))
 387                                         earliest = expire_at;
 388                                 continue;
 389                         }
 390                 }
 391
 392                 /* The usage count sits at 1 whilst the object is unused on the
 393                  * list; we reduce that to 0 to make the object unavailable.
 394                  */
 395                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 396                         continue;
 397                 trace_rxrpc_conn(conn, rxrpc_conn_reap_service, 0, 0);
 398
 399                 if (rxrpc_conn_is_client(conn))
 400                         BUG();
 401                 else
 402                         rxrpc_unpublish_service_conn(conn);
 403
 404                 list_move_tail(&conn->link, &graveyard);
 405         }
 406         write_unlock(&rxnet->conn_lock);
 407
 408         if (earliest != now + MAX_JIFFY_OFFSET) {
 409                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
 410                 ASSERT(time_after(earliest, now));
 411                 rxrpc_queue_delayed_work(&rxnet->service_conn_reaper,
 412                                          earliest - now);
 413         }
 414
 415         while (!list_empty(&graveyard)) {
 416                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 417                                   link);
 418                 list_del_init(&conn->link);
 419
 420                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 421                 rxrpc_kill_connection(conn);
 422         }
 423
 424         _leave("");
 425 }
 426
 427 /*
 428  * preemptively destroy all the service connection records rather than
 429  * waiting for them to time out
 430  */
 431 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
 432 {
 433         struct rxrpc_connection *conn, *_p;
 434         bool leak = false;
 435
 436         _enter("");
 437
 438         rxrpc_destroy_all_client_connections(rxnet);
 439
 440         cancel_delayed_work(&rxnet->client_conn_reaper);
 441         rxrpc_queue_delayed_work(&rxnet->client_conn_reaper, 0);
 442         flush_workqueue(rxrpc_workqueue);
 443
 444         write_lock(&rxnet->conn_lock);
 445         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 446                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 447                        conn, atomic_read(&conn->usage));
 448                 leak = true;
 449         }
 450         write_unlock(&rxnet->conn_lock);
 451         BUG_ON(leak);
 452
 453         ASSERT(list_empty(&rxnet->conn_proc_list));
 454
 455         _leave("");
 456 }