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->header_size = sizeof(struct rxrpc_wire_header);
  57                 conn->idle_timestamp = jiffies;
  58         }
  59
  60         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
  61         return conn;
  62 }
  63
  64 /*
  65  * Look up a connection in the cache by protocol parameters.
  66  *
  67  * If successful, a pointer to the connection is returned, but no ref is taken.
  68  * NULL is returned if there is no match.
  69  *
  70  * The caller must be holding the RCU read lock.
  71  */
  72 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
  73                                                    struct sk_buff *skb)
  74 {
  75         struct rxrpc_connection *conn;
  76         struct rxrpc_conn_proto k;
  77         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  78         struct sockaddr_rxrpc srx;
  79         struct rxrpc_peer *peer;
  80
  81         _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
  82
  83         if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
  84                 goto not_found;
  85
  86         k.epoch = sp->hdr.epoch;
  87         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
  88
  89         /* We may have to handle mixing IPv4 and IPv6 */
  90         if (srx.transport.family != local->srx.transport.family) {
  91                 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
  92                                     srx.transport.family,
  93                                     local->srx.transport.family);
  94                 goto not_found;
  95         }
  96
  97         k.epoch = sp->hdr.epoch;
  98         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
  99
 100         if (sp->hdr.flags & RXRPC_CLIENT_INITIATED) {
 101                 /* We need to look up service connections by the full protocol
 102                  * parameter set.  We look up the peer first as an intermediate
 103                  * step and then the connection from the peer's tree.
 104                  */
 105                 peer = rxrpc_lookup_peer_rcu(local, &srx);
 106                 if (!peer)
 107                         goto not_found;
 108                 conn = rxrpc_find_service_conn_rcu(peer, skb);
 109                 if (!conn || atomic_read(&conn->usage) == 0)
 110                         goto not_found;
 111                 _leave(" = %p", conn);
 112                 return conn;
 113         } else {
 114                 /* Look up client connections by connection ID alone as their
 115                  * IDs are unique for this machine.
 116                  */
 117                 conn = idr_find(&rxrpc_client_conn_ids,
 118                                 sp->hdr.cid >> RXRPC_CIDSHIFT);
 119                 if (!conn || atomic_read(&conn->usage) == 0) {
 120                         _debug("no conn");
 121                         goto not_found;
 122                 }
 123
 124                 if (conn->proto.epoch != k.epoch ||
 125                     conn->params.local != local)
 126                         goto not_found;
 127
 128                 peer = conn->params.peer;
 129                 switch (srx.transport.family) {
 130                 case AF_INET:
 131                         if (peer->srx.transport.sin.sin_port !=
 132                             srx.transport.sin.sin_port ||
 133                             peer->srx.transport.sin.sin_addr.s_addr !=
 134                             srx.transport.sin.sin_addr.s_addr)
 135                                 goto not_found;
 136                         break;
 137                 default:
 138                         BUG();
 139                 }
 140
 141                 _leave(" = %p", conn);
 142                 return conn;
 143         }
 144
 145 not_found:
 146         _leave(" = NULL");
 147         return NULL;
 148 }
 149
 150 /*
 151  * Disconnect a call and clear any channel it occupies when that call
 152  * terminates.  The caller must hold the channel_lock and must release the
 153  * call's ref on the connection.
 154  */
 155 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
 156                              struct rxrpc_call *call)
 157 {
 158         struct rxrpc_channel *chan =
 159                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
 160
 161         _enter("%d,%x", conn->debug_id, call->cid);
 162
 163         if (rcu_access_pointer(chan->call) == call) {
 164                 /* Save the result of the call so that we can repeat it if necessary
 165                  * through the channel, whilst disposing of the actual call record.
 166                  */
 167                 chan->last_service_id = call->service_id;
 168                 if (call->abort_code) {
 169                         chan->last_abort = call->abort_code;
 170                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
 171                 } else {
 172                         chan->last_seq = call->rx_hard_ack;
 173                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
 174                 }
 175                 /* Sync with rxrpc_conn_retransmit(). */
 176                 smp_wmb();
 177                 chan->last_call = chan->call_id;
 178                 chan->call_id = chan->call_counter;
 179
 180                 rcu_assign_pointer(chan->call, NULL);
 181         }
 182
 183         _leave("");
 184 }
 185
 186 /*
 187  * Disconnect a call and clear any channel it occupies when that call
 188  * terminates.
 189  */
 190 void rxrpc_disconnect_call(struct rxrpc_call *call)
 191 {
 192         struct rxrpc_connection *conn = call->conn;
 193
 194         spin_lock_bh(&conn->params.peer->lock);
 195         hlist_del_init(&call->error_link);
 196         spin_unlock_bh(&conn->params.peer->lock);
 197
 198         if (rxrpc_is_client_call(call))
 199                 return rxrpc_disconnect_client_call(call);
 200
 201         spin_lock(&conn->channel_lock);
 202         __rxrpc_disconnect_call(conn, call);
 203         spin_unlock(&conn->channel_lock);
 204
 205         call->conn = NULL;
 206         conn->idle_timestamp = jiffies;
 207         rxrpc_put_connection(conn);
 208 }
 209
 210 /*
 211  * Kill off a connection.
 212  */
 213 void rxrpc_kill_connection(struct rxrpc_connection *conn)
 214 {
 215         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
 216                !rcu_access_pointer(conn->channels[1].call) &&
 217                !rcu_access_pointer(conn->channels[2].call) &&
 218                !rcu_access_pointer(conn->channels[3].call));
 219         ASSERT(list_empty(&conn->cache_link));
 220
 221         write_lock(&rxrpc_connection_lock);
 222         list_del_init(&conn->proc_link);
 223         write_unlock(&rxrpc_connection_lock);
 224
 225         /* Drain the Rx queue.  Note that even though we've unpublished, an
 226          * incoming packet could still be being added to our Rx queue, so we
 227          * will need to drain it again in the RCU cleanup handler.
 228          */
 229         rxrpc_purge_queue(&conn->rx_queue);
 230
 231         /* Leave final destruction to RCU.  The connection processor work item
 232          * must carry a ref on the connection to prevent us getting here whilst
 233          * it is queued or running.
 234          */
 235         call_rcu(&conn->rcu, rxrpc_destroy_connection);
 236 }
 237
 238 /*
 239  * release a virtual connection
 240  */
 241 void __rxrpc_put_connection(struct rxrpc_connection *conn)
 242 {
 243         rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 244 }
 245
 246 /*
 247  * destroy a virtual connection
 248  */
 249 static void rxrpc_destroy_connection(struct rcu_head *rcu)
 250 {
 251         struct rxrpc_connection *conn =
 252                 container_of(rcu, struct rxrpc_connection, rcu);
 253
 254         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
 255
 256         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 257
 258         _net("DESTROY CONN %d", conn->debug_id);
 259
 260         rxrpc_purge_queue(&conn->rx_queue);
 261
 262         conn->security->clear(conn);
 263         key_put(conn->params.key);
 264         key_put(conn->server_key);
 265         rxrpc_put_peer(conn->params.peer);
 266         rxrpc_put_local(conn->params.local);
 267
 268         kfree(conn);
 269         _leave("");
 270 }
 271
 272 /*
 273  * reap dead service connections
 274  */
 275 static void rxrpc_connection_reaper(struct work_struct *work)
 276 {
 277         struct rxrpc_connection *conn, *_p;
 278         unsigned long reap_older_than, earliest, idle_timestamp, now;
 279
 280         LIST_HEAD(graveyard);
 281
 282         _enter("");
 283
 284         now = jiffies;
 285         reap_older_than = now - rxrpc_connection_expiry * HZ;
 286         earliest = ULONG_MAX;
 287
 288         write_lock(&rxrpc_connection_lock);
 289         list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
 290                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
 291                 if (likely(atomic_read(&conn->usage) > 1))
 292                         continue;
 293                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
 294                         continue;
 295
 296                 idle_timestamp = READ_ONCE(conn->idle_timestamp);
 297                 _debug("reap CONN %d { u=%d,t=%ld }",
 298                        conn->debug_id, atomic_read(&conn->usage),
 299                        (long)reap_older_than - (long)idle_timestamp);
 300
 301                 if (time_after(idle_timestamp, reap_older_than)) {
 302                         if (time_before(idle_timestamp, earliest))
 303                                 earliest = idle_timestamp;
 304                         continue;
 305                 }
 306
 307                 /* The usage count sits at 1 whilst the object is unused on the
 308                  * list; we reduce that to 0 to make the object unavailable.
 309                  */
 310                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 311                         continue;
 312
 313                 if (rxrpc_conn_is_client(conn))
 314                         BUG();
 315                 else
 316                         rxrpc_unpublish_service_conn(conn);
 317
 318                 list_move_tail(&conn->link, &graveyard);
 319         }
 320         write_unlock(&rxrpc_connection_lock);
 321
 322         if (earliest != ULONG_MAX) {
 323                 _debug("reschedule reaper %ld", (long) earliest - now);
 324                 ASSERT(time_after(earliest, now));
 325                 rxrpc_queue_delayed_work(&rxrpc_connection_reap,
 326                                          earliest - now);
 327         }
 328
 329         while (!list_empty(&graveyard)) {
 330                 conn = list_entry(graveyard.next, struct rxrpc_connection,
 331                                   link);
 332                 list_del_init(&conn->link);
 333
 334                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
 335                 rxrpc_kill_connection(conn);
 336         }
 337
 338         _leave("");
 339 }
 340
 341 /*
 342  * preemptively destroy all the service connection records rather than
 343  * waiting for them to time out
 344  */
 345 void __exit rxrpc_destroy_all_connections(void)
 346 {
 347         struct rxrpc_connection *conn, *_p;
 348         bool leak = false;
 349
 350         _enter("");
 351
 352         rxrpc_destroy_all_client_connections();
 353
 354         rxrpc_connection_expiry = 0;
 355         cancel_delayed_work(&rxrpc_connection_reap);
 356         rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
 357         flush_workqueue(rxrpc_workqueue);
 358
 359         write_lock(&rxrpc_connection_lock);
 360         list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
 361                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
 362                        conn, atomic_read(&conn->usage));
 363                 leak = true;
 364         }
 365         write_unlock(&rxrpc_connection_lock);
 366         BUG_ON(leak);
 367
 368         ASSERT(list_empty(&rxrpc_connection_proc_list));
 369
 370         /* Make sure the local and peer records pinned by any dying connections
 371          * are released.
 372          */
 373         rcu_barrier();
 374         rxrpc_destroy_client_conn_ids();
 375
 376         _leave("");
 377 }