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 static void rxrpc_connection_timer(struct timer_list *timer)
  29 {
  30         struct rxrpc_connection *conn =
  31                 container_of(timer, struct rxrpc_connection, timer);
  32
  33         rxrpc_queue_conn(conn);
  34 }
  35
  36 /*
  37  * allocate a new connection
  38  */
  39 struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
  40 {
  41         struct rxrpc_connection *conn;
  42
  43         _enter("");
  44
  45         conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
  46         if (conn) {
  47                 INIT_LIST_HEAD(&conn->cache_link);
  48                 spin_lock_init(&conn->channel_lock);
  49                 INIT_LIST_HEAD(&conn->waiting_calls);
  50                 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
  51                 INIT_WORK(&conn->processor, &rxrpc_process_connection);
  52                 INIT_LIST_HEAD(&conn->proc_link);
  53                 INIT_LIST_HEAD(&conn->link);
  54                 skb_queue_head_init(&conn->rx_queue);
  55                 conn->security = &rxrpc_no_security;
  56                 spin_lock_init(&conn->state_lock);
  57                 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
  58                 conn->size_align = 4;
  59                 conn->idle_timestamp = jiffies;
  60         }
  61
  62         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
  63         return conn;
  64 }
  65
  66 /*
  67  * Look up a connection in the cache by protocol parameters.
  68  *
  69  * If successful, a pointer to the connection is returned, but no ref is taken.
  70  * NULL is returned if there is no match.
  71  *
  72  * The caller must be holding the RCU read lock.
  73  */
  74 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
  75                                                    struct sk_buff *skb)
  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(local, &srx, skb) < 0)
  86                 goto not_found;
  87
  88         k.epoch = sp->hdr.epoch;
  89         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
  90
  91         /* We may have to handle mixing IPv4 and IPv6 */
  92         if (srx.transport.family != local->srx.transport.family) {
  93                 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
  94                                     srx.transport.family,
  95                                     local->srx.transport.family);
  96                 goto not_found;
  97         }
  98
  99         k.epoch = sp->hdr.epoch;
 100         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
 101
 102         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED) {
 103                 /* We need to look up service connections by the full protocol
 104                  * parameter set.  We look up the peer first as an intermediate
 105                  * step and then the connection from the peer's tree.
 106                  */
 107                 peer = rxrpc_lookup_peer_rcu(local, &srx);
 108                 if (!peer)
 109                         goto not_found;
 110                 conn = rxrpc_find_service_conn_rcu(peer, skb);
 111                 if (!conn || atomic_read(&conn->usage) == 0)
 112                         goto not_found;
 113                 _leave(" = %p", conn);
 114                 return conn;
 115         } else {
 116                 /* Look up client connections by connection ID alone as their
 117                  * IDs are unique for this machine.
 118                  */
 119                 conn = idr_find(&rxrpc_client_conn_ids,
 120                                 sp->hdr.cid >> RXRPC_CIDSHIFT);
 121                 if (!conn || atomic_read(&conn->usage) == 0) {
 122                         _debug("no conn");
 123                         goto not_found;
 124                 }
 125
 126                 if (conn->proto.epoch != k.epoch ||
 127                     conn->params.local != local)
 128                         goto not_found;
 129
 130                 peer = conn->params.peer;
 131                 switch (srx.transport.family) {
 132                 case AF_INET:
 133                         if (peer->srx.transport.sin.sin_port !=
 134                             srx.transport.sin.sin_port ||
 135                             peer->srx.transport.sin.sin_addr.s_addr !=
 136                             srx.transport.sin.sin_addr.s_addr)
 137                                 goto not_found;
 138                         break;
 139 #ifdef CONFIG_AF_RXRPC_IPV6
 140                 case AF_INET6:
 141                         if (peer->srx.transport.sin6.sin6_port !=
 142                             srx.transport.sin6.sin6_port ||
 143                             memcmp(&peer->srx.transport.sin6.sin6_addr,
 144                                    &srx.transport.sin6.sin6_addr,
 145                                    sizeof(struct in6_addr)) != 0)
 146                                 goto not_found;
 147                         break;
 148 #endif
 149                 default:
 150                         BUG();
 151                 }
 152
 153                 _leave(" = %p", conn);
 154                 return conn;
 155         }
 156
 157 not_found:
 158         _leave(" = NULL");
 159         return NULL;
 160 }
 161
 162 /*
 163  * Disconnect a call and clear any channel it occupies when that call
 164  * terminates.  The caller must hold the channel_lock and must release the
 165  * call's ref on the connection.
 166  */
 167 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
 168                              struct rxrpc_call *call)
 169 {
 170         struct rxrpc_channel *chan =
 171                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
 172
 173         _enter("%d,%x", conn->debug_id, call->cid);
 174
 175         if (rcu_access_pointer(chan->call) == call) {
 176                 /* Save the result of the call so that we can repeat it if necessary
 177                  * through the channel, whilst disposing of the actual call record.
 178                  */
 179                 trace_rxrpc_disconnect_call(call);
 180                 if (call->abort_code) {
 181                         chan->last_abort = call->abort_code;
 182                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 183                 } else {
 184                         chan->last_seq = call->rx_hard_ack;
 185                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 186                 }
 187                 /* Sync with rxrpc_conn_retransmit(). */
 188                 smp_wmb();
 189                 chan->last_call = chan->call_id;
 190                 chan->call_id = chan->call_counter;
 191
 192                 rcu_assign_pointer(chan->call, NULL);
 193         }
 194
 195         _leave("");
 196 }
 197
 198 /*
 199  * Disconnect a call and clear any channel it occupies when that call
 200  * terminates.
 201  */
 202 void rxrpc_disconnect_call(struct rxrpc_call *call)
 203 {
 204         struct rxrpc_connection *conn = call->conn;
 205
 206         call->peer->cong_cwnd = call->cong_cwnd;
 207
 208         spin_lock_bh(&conn->params.peer->lock);
 209         hlist_del_init(&call->error_link);
 210         spin_unlock_bh(&conn->params.peer->lock);
 211
 212         if (rxrpc_is_client_call(call))
 213                 return rxrpc_disconnect_client_call(call);
 214
 215         spin_lock(&conn->channel_lock);
 216         __rxrpc_disconnect_call(conn, call);
 217         spin_unlock(&conn->channel_lock);
 218
 219         call->conn = NULL;
 220         conn->idle_timestamp = jiffies;
 221         rxrpc_put_connection(conn);
 222 }
 223
 224 /*
 225  * Kill off a connection.
 226  */
 227 void rxrpc_kill_connection(struct rxrpc_connection *conn)
 228 {
 229         struct rxrpc_net *rxnet = conn->params.local->rxnet;
 230
 231         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 232                !rcu_access_pointer(conn->channels[1].call) &&
 233                !rcu_access_pointer(conn->channels[2].call) &&
 234                !rcu_access_pointer(conn->channels[3].call));
 235         ASSERT(list_empty(&conn->cache_link));
 236
 237         write_lock(&rxnet->conn_lock);
 238         list_del_init(&conn->proc_link);
 239         write_unlock(&rxnet->conn_lock);
 240
 241         /* Drain the Rx queue.  Note that even though we've unpublished, an
 242          * incoming packet could still be being added to our Rx queue, so we
 243          * will need to drain it again in the RCU cleanup handler.
 244          */
 245         rxrpc_purge_queue(&conn->rx_queue);
 246
 247         /* Leave final destruction to RCU.  The connection processor work item
 248          * must carry a ref on the connection to prevent us getting here whilst
 249          * it is queued or running.
 250          */
 251         call_rcu(&conn->rcu, rxrpc_destroy_connection);
 252 }
 253
 254 /*
 255  * Queue a connection's work processor, getting a ref to pass to the work
 256  * queue.
 257  */
 258 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 259 {
 260         const void *here = __builtin_return_address(0);
 261         int n = __atomic_add_unless(&conn->usage, 1, 0);
 262         if (n == 0)
 263                 return false;
 264         if (rxrpc_queue_work(&conn->processor))
 265                 trace_rxrpc_conn(conn, rxrpc_conn_queued, n + 1, here);
 266         else
 267                 rxrpc_put_connection(conn);
 268         return true;
 269 }
 270
 271 /*
 272  * Note the re-emergence of a connection.
 273  */
 274 void rxrpc_see_connection(struct rxrpc_connection *conn)
 275 {
 276         const void *here = __builtin_return_address(0);
 277         if (conn) {
 278                 int n = atomic_read(&conn->usage);
 279
 280                 trace_rxrpc_conn(conn, rxrpc_conn_seen, n, here);
 281         }
 282 }
 283
 284 /*
 285  * Get a ref on a connection.
 286  */
 287 void rxrpc_get_connection(struct rxrpc_connection *conn)
 288 {
 289         const void *here = __builtin_return_address(0);
 290         int n = atomic_inc_return(&conn->usage);
 291
 292         trace_rxrpc_conn(conn, rxrpc_conn_got, n, here);
 293 }
 294
 295 /*
 296  * Try to get a ref on a connection.
 297  */
 298 struct rxrpc_connection *
 299 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
 300 {
 301         const void *here = __builtin_return_address(0);
 302
 303         if (conn) {
 304                 int n = __atomic_add_unless(&conn->usage, 1, 0);
 305                 if (n > 0)
 306                         trace_rxrpc_conn(conn, rxrpc_conn_got, n + 1, here);
 307                 else
 308                         conn = NULL;
 309         }
 310         return conn;
 311 }
 312
 313 /*
 314  * Set the service connection reap timer.
 315  */
 316 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
 317                                          unsigned long reap_at)
 318 {
 319         if (rxnet->live)
 320                 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
 321 }
 322
 323 /*
 324  * Release a service connection
 325  */
 326 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
 327 {
 328         const void *here = __builtin_return_address(0);
 329         int n;
 330
 331         n = atomic_dec_return(&conn->usage);
 332         trace_rxrpc_conn(conn, rxrpc_conn_put_service, n, here);
 333         ASSERTCMP(n, >=, 0);
 334         if (n == 1)
 335                 rxrpc_set_service_reap_timer(conn->params.local->rxnet,
 336                                              jiffies + rxrpc_connection_expiry);
 337 }
 338
 339 /*
 340  * destroy a virtual connection
 341  */
 342 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 343 {
 344         struct rxrpc_connection *conn =
 345                 container_of(rcu, struct rxrpc_connection, rcu);
 346
 347         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
 348
 349         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 350
 351         _net("DESTROY CONN %d", conn->debug_id);
 352
 353         del_timer_sync(&conn->timer);
 354         rxrpc_purge_queue(&conn->rx_queue);
 355
 356         conn->security->clear(conn);
 357         key_put(conn->params.key);
 358         key_put(conn->server_key);
 359         rxrpc_put_peer(conn->params.peer);
 360         rxrpc_put_local(conn->params.local);
 361
 362         kfree(conn);
 363         _leave("");
 364 }
 365
 366 /*
 367  * reap dead service connections
 368  */
 369 void rxrpc_service_connection_reaper(struct work_struct *work)
 370 {
 371         struct rxrpc_connection *conn, *_p;
 372         struct rxrpc_net *rxnet =
 373                 container_of(work, struct rxrpc_net, service_conn_reaper);
 374         unsigned long expire_at, earliest, idle_timestamp, now;
 375
 376         LIST_HEAD(graveyard);
 377
 378         _enter("");
 379
 380         now = jiffies;
 381         earliest = now + MAX_JIFFY_OFFSET;
 382
 383         write_lock(&rxnet->conn_lock);
 384         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 385                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
 386                 if (likely(atomic_read(&conn->usage) > 1))
 387                         continue;
 388                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 389                         continue;
 390
 391                 if (rxnet->live) {
 392                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
 393                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
 394                         if (conn->params.local->service_closed)
 395                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
 396
 397                         _debug("reap CONN %d { u=%d,t=%ld }",
 398                                conn->debug_id, atomic_read(&conn->usage),
 399                                (long)expire_at - (long)now);
 400
 401                         if (time_before(now, expire_at)) {
 402                                 if (time_before(expire_at, earliest))
 403                                         earliest = expire_at;
 404                                 continue;
 405                         }
 406                 }
 407
 408                 /* The usage count sits at 1 whilst the object is unused on the
 409                  * list; we reduce that to 0 to make the object unavailable.
 410                  */
 411                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 412                         continue;
 413                 trace_rxrpc_conn(conn, rxrpc_conn_reap_service, 0, 0);
 414
 415                 if (rxrpc_conn_is_client(conn))
 416                         BUG();
 417                 else
 418                         rxrpc_unpublish_service_conn(conn);
 419
 420                 list_move_tail(&conn->link, &graveyard);
 421         }
 422         write_unlock(&rxnet->conn_lock);
 423
 424         if (earliest != now + MAX_JIFFY_OFFSET) {
 425                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
 426                 ASSERT(time_after(earliest, now));
 427                 rxrpc_set_service_reap_timer(rxnet, earliest);
 428         }
 429
 430         while (!list_empty(&graveyard)) {
 431                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 432                                   link);
 433                 list_del_init(&conn->link);
 434
 435                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 436                 rxrpc_kill_connection(conn);
 437         }
 438
 439         _leave("");
 440 }
 441
 442 /*
 443  * preemptively destroy all the service connection records rather than
 444  * waiting for them to time out
 445  */
 446 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
 447 {
 448         struct rxrpc_connection *conn, *_p;
 449         bool leak = false;
 450
 451         _enter("");
 452
 453         rxrpc_destroy_all_client_connections(rxnet);
 454
 455         del_timer_sync(&rxnet->service_conn_reap_timer);
 456         rxrpc_queue_work(&rxnet->service_conn_reaper);
 457         flush_workqueue(rxrpc_workqueue);
 458
 459         write_lock(&rxnet->conn_lock);
 460         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
 461                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 462                        conn, atomic_read(&conn->usage));
 463                 leak = true;
 464         }
 465         write_unlock(&rxnet->conn_lock);
 466         BUG_ON(leak);
 467
 468         ASSERT(list_empty(&rxnet->conn_proc_list));
 469
 470         _leave("");
 471 }