net/rxrpc/conn_object.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /* RxRPC virtual connection handler, common bits.
0003  *
0004  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
0005  * Written by David Howells (dhowells@redhat.com)
0006  */
0007
0008 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0009
0010 #include <linux/module.h>
0011 #include <linux/slab.h>
0012 #include <linux/net.h>
0013 #include <linux/skbuff.h>
0014 #include "ar-internal.h"
0015
0016 /*
0017  * Time till a connection expires after last use (in seconds).
0018  */
0019 unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
0020 unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
0021
0022 static void rxrpc_destroy_connection(struct rcu_head *);
0023
0024 static void rxrpc_connection_timer(struct timer_list *timer)
0025 {
0026     struct rxrpc_connection *conn =
0027         container_of(timer, struct rxrpc_connection, timer);
0028
0029     rxrpc_queue_conn(conn);
0030 }
0031
0032 /*
0033  * allocate a new connection
0034  */
0035 struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
0036 {
0037     struct rxrpc_connection *conn;
0038
0039     _enter("");
0040
0041     conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
0042     if (conn) {
0043         INIT_LIST_HEAD(&conn->cache_link);
0044         timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
0045         INIT_WORK(&conn->processor, &rxrpc_process_connection);
0046         INIT_LIST_HEAD(&conn->proc_link);
0047         INIT_LIST_HEAD(&conn->link);
0048         skb_queue_head_init(&conn->rx_queue);
0049         conn->security = &rxrpc_no_security;
0050         spin_lock_init(&conn->state_lock);
0051         conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
0052         conn->idle_timestamp = jiffies;
0053     }
0054
0055     _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
0056     return conn;
0057 }
0058
0059 /*
0060  * Look up a connection in the cache by protocol parameters.
0061  *
0062  * If successful, a pointer to the connection is returned, but no ref is taken.
0063  * NULL is returned if there is no match.
0064  *
0065  * When searching for a service call, if we find a peer but no connection, we
0066  * return that through *_peer in case we need to create a new service call.
0067  *
0068  * The caller must be holding the RCU read lock.
0069  */
0070 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
0071                            struct sk_buff *skb,
0072                            struct rxrpc_peer **_peer)
0073 {
0074     struct rxrpc_connection *conn;
0075     struct rxrpc_conn_proto k;
0076     struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
0077     struct sockaddr_rxrpc srx;
0078     struct rxrpc_peer *peer;
0079
0080     _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
0081
0082     if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
0083         goto not_found;
0084
0085     if (srx.transport.family != local->srx.transport.family &&
0086         (srx.transport.family == AF_INET &&
0087          local->srx.transport.family != AF_INET6)) {
0088         pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
0089                     srx.transport.family,
0090                     local->srx.transport.family);
0091         goto not_found;
0092     }
0093
0094     k.epoch = sp->hdr.epoch;
0095     k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
0096
0097     if (rxrpc_to_server(sp)) {
0098         /* We need to look up service connections by the full protocol
0099          * parameter set.  We look up the peer first as an intermediate
0100          * step and then the connection from the peer's tree.
0101          */
0102         peer = rxrpc_lookup_peer_rcu(local, &srx);
0103         if (!peer)
0104             goto not_found;
0105         *_peer = peer;
0106         conn = rxrpc_find_service_conn_rcu(peer, skb);
0107         if (!conn || refcount_read(&conn->ref) == 0)
0108             goto not_found;
0109         _leave(" = %p", conn);
0110         return conn;
0111     } else {
0112         /* Look up client connections by connection ID alone as their
0113          * IDs are unique for this machine.
0114          */
0115         conn = idr_find(&rxrpc_client_conn_ids,
0116                 sp->hdr.cid >> RXRPC_CIDSHIFT);
0117         if (!conn || refcount_read(&conn->ref) == 0) {
0118             _debug("no conn");
0119             goto not_found;
0120         }
0121
0122         if (conn->proto.epoch != k.epoch ||
0123             conn->params.local != local)
0124             goto not_found;
0125
0126         peer = conn->params.peer;
0127         switch (srx.transport.family) {
0128         case AF_INET:
0129             if (peer->srx.transport.sin.sin_port !=
0130                 srx.transport.sin.sin_port ||
0131                 peer->srx.transport.sin.sin_addr.s_addr !=
0132                 srx.transport.sin.sin_addr.s_addr)
0133                 goto not_found;
0134             break;
0135 #ifdef CONFIG_AF_RXRPC_IPV6
0136         case AF_INET6:
0137             if (peer->srx.transport.sin6.sin6_port !=
0138                 srx.transport.sin6.sin6_port ||
0139                 memcmp(&peer->srx.transport.sin6.sin6_addr,
0140                    &srx.transport.sin6.sin6_addr,
0141                    sizeof(struct in6_addr)) != 0)
0142                 goto not_found;
0143             break;
0144 #endif
0145         default:
0146             BUG();
0147         }
0148
0149         _leave(" = %p", conn);
0150         return conn;
0151     }
0152
0153 not_found:
0154     _leave(" = NULL");
0155     return NULL;
0156 }
0157
0158 /*
0159  * Disconnect a call and clear any channel it occupies when that call
0160  * terminates.  The caller must hold the channel_lock and must release the
0161  * call's ref on the connection.
0162  */
0163 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
0164                  struct rxrpc_call *call)
0165 {
0166     struct rxrpc_channel *chan =
0167         &conn->channels[call->cid & RXRPC_CHANNELMASK];
0168
0169     _enter("%d,%x", conn->debug_id, call->cid);
0170
0171     if (rcu_access_pointer(chan->call) == call) {
0172         /* Save the result of the call so that we can repeat it if necessary
0173          * through the channel, whilst disposing of the actual call record.
0174          */
0175         trace_rxrpc_disconnect_call(call);
0176         switch (call->completion) {
0177         case RXRPC_CALL_SUCCEEDED:
0178             chan->last_seq = call->rx_hard_ack;
0179             chan->last_type = RXRPC_PACKET_TYPE_ACK;
0180             break;
0181         case RXRPC_CALL_LOCALLY_ABORTED:
0182             chan->last_abort = call->abort_code;
0183             chan->last_type = RXRPC_PACKET_TYPE_ABORT;
0184             break;
0185         default:
0186             chan->last_abort = RX_CALL_DEAD;
0187             chan->last_type = RXRPC_PACKET_TYPE_ABORT;
0188             break;
0189         }
0190
0191         /* Sync with rxrpc_conn_retransmit(). */
0192         smp_wmb();
0193         chan->last_call = chan->call_id;
0194         chan->call_id = chan->call_counter;
0195
0196         rcu_assign_pointer(chan->call, NULL);
0197     }
0198
0199     _leave("");
0200 }
0201
0202 /*
0203  * Disconnect a call and clear any channel it occupies when that call
0204  * terminates.
0205  */
0206 void rxrpc_disconnect_call(struct rxrpc_call *call)
0207 {
0208     struct rxrpc_connection *conn = call->conn;
0209
0210     call->peer->cong_cwnd = call->cong_cwnd;
0211
0212     if (!hlist_unhashed(&call->error_link)) {
0213         spin_lock_bh(&call->peer->lock);
0214         hlist_del_rcu(&call->error_link);
0215         spin_unlock_bh(&call->peer->lock);
0216     }
0217
0218     if (rxrpc_is_client_call(call))
0219         return rxrpc_disconnect_client_call(conn->bundle, call);
0220
0221     spin_lock(&conn->bundle->channel_lock);
0222     __rxrpc_disconnect_call(conn, call);
0223     spin_unlock(&conn->bundle->channel_lock);
0224
0225     set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
0226     conn->idle_timestamp = jiffies;
0227 }
0228
0229 /*
0230  * Kill off a connection.
0231  */
0232 void rxrpc_kill_connection(struct rxrpc_connection *conn)
0233 {
0234     struct rxrpc_net *rxnet = conn->params.local->rxnet;
0235
0236     ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
0237            !rcu_access_pointer(conn->channels[1].call) &&
0238            !rcu_access_pointer(conn->channels[2].call) &&
0239            !rcu_access_pointer(conn->channels[3].call));
0240     ASSERT(list_empty(&conn->cache_link));
0241
0242     write_lock(&rxnet->conn_lock);
0243     list_del_init(&conn->proc_link);
0244     write_unlock(&rxnet->conn_lock);
0245
0246     /* Drain the Rx queue.  Note that even though we've unpublished, an
0247      * incoming packet could still be being added to our Rx queue, so we
0248      * will need to drain it again in the RCU cleanup handler.
0249      */
0250     rxrpc_purge_queue(&conn->rx_queue);
0251
0252     /* Leave final destruction to RCU.  The connection processor work item
0253      * must carry a ref on the connection to prevent us getting here whilst
0254      * it is queued or running.
0255      */
0256     call_rcu(&conn->rcu, rxrpc_destroy_connection);
0257 }
0258
0259 /*
0260  * Queue a connection's work processor, getting a ref to pass to the work
0261  * queue.
0262  */
0263 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
0264 {
0265     const void *here = __builtin_return_address(0);
0266     int r;
0267
0268     if (!__refcount_inc_not_zero(&conn->ref, &r))
0269         return false;
0270     if (rxrpc_queue_work(&conn->processor))
0271         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, r + 1, here);
0272     else
0273         rxrpc_put_connection(conn);
0274     return true;
0275 }
0276
0277 /*
0278  * Note the re-emergence of a connection.
0279  */
0280 void rxrpc_see_connection(struct rxrpc_connection *conn)
0281 {
0282     const void *here = __builtin_return_address(0);
0283     if (conn) {
0284         int n = refcount_read(&conn->ref);
0285
0286         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_seen, n, here);
0287     }
0288 }
0289
0290 /*
0291  * Get a ref on a connection.
0292  */
0293 struct rxrpc_connection *rxrpc_get_connection(struct rxrpc_connection *conn)
0294 {
0295     const void *here = __builtin_return_address(0);
0296     int r;
0297
0298     __refcount_inc(&conn->ref, &r);
0299     trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, r, here);
0300     return conn;
0301 }
0302
0303 /*
0304  * Try to get a ref on a connection.
0305  */
0306 struct rxrpc_connection *
0307 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
0308 {
0309     const void *here = __builtin_return_address(0);
0310     int r;
0311
0312     if (conn) {
0313         if (__refcount_inc_not_zero(&conn->ref, &r))
0314             trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, r + 1, here);
0315         else
0316             conn = NULL;
0317     }
0318     return conn;
0319 }
0320
0321 /*
0322  * Set the service connection reap timer.
0323  */
0324 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
0325                      unsigned long reap_at)
0326 {
0327     if (rxnet->live)
0328         timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
0329 }
0330
0331 /*
0332  * Release a service connection
0333  */
0334 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
0335 {
0336     const void *here = __builtin_return_address(0);
0337     unsigned int debug_id = conn->debug_id;
0338     int r;
0339
0340     __refcount_dec(&conn->ref, &r);
0341     trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, r - 1, here);
0342     if (r - 1 == 1)
0343         rxrpc_set_service_reap_timer(conn->params.local->rxnet,
0344                          jiffies + rxrpc_connection_expiry);
0345 }
0346
0347 /*
0348  * destroy a virtual connection
0349  */
0350 static void rxrpc_destroy_connection(struct rcu_head *rcu)
0351 {
0352     struct rxrpc_connection *conn =
0353         container_of(rcu, struct rxrpc_connection, rcu);
0354
0355     _enter("{%d,u=%d}", conn->debug_id, refcount_read(&conn->ref));
0356
0357     ASSERTCMP(refcount_read(&conn->ref), ==, 0);
0358
0359     _net("DESTROY CONN %d", conn->debug_id);
0360
0361     del_timer_sync(&conn->timer);
0362     rxrpc_purge_queue(&conn->rx_queue);
0363
0364     conn->security->clear(conn);
0365     key_put(conn->params.key);
0366     rxrpc_put_bundle(conn->bundle);
0367     rxrpc_put_peer(conn->params.peer);
0368
0369     if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
0370         wake_up_var(&conn->params.local->rxnet->nr_conns);
0371     rxrpc_put_local(conn->params.local);
0372
0373     kfree(conn);
0374     _leave("");
0375 }
0376
0377 /*
0378  * reap dead service connections
0379  */
0380 void rxrpc_service_connection_reaper(struct work_struct *work)
0381 {
0382     struct rxrpc_connection *conn, *_p;
0383     struct rxrpc_net *rxnet =
0384         container_of(work, struct rxrpc_net, service_conn_reaper);
0385     unsigned long expire_at, earliest, idle_timestamp, now;
0386
0387     LIST_HEAD(graveyard);
0388
0389     _enter("");
0390
0391     now = jiffies;
0392     earliest = now + MAX_JIFFY_OFFSET;
0393
0394     write_lock(&rxnet->conn_lock);
0395     list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
0396         ASSERTCMP(refcount_read(&conn->ref), >, 0);
0397         if (likely(refcount_read(&conn->ref) > 1))
0398             continue;
0399         if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
0400             continue;
0401
0402         if (rxnet->live && !conn->params.local->dead) {
0403             idle_timestamp = READ_ONCE(conn->idle_timestamp);
0404             expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
0405             if (conn->params.local->service_closed)
0406                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
0407
0408             _debug("reap CONN %d { u=%d,t=%ld }",
0409                    conn->debug_id, refcount_read(&conn->ref),
0410                    (long)expire_at - (long)now);
0411
0412             if (time_before(now, expire_at)) {
0413                 if (time_before(expire_at, earliest))
0414                     earliest = expire_at;
0415                 continue;
0416             }
0417         }
0418
0419         /* The usage count sits at 1 whilst the object is unused on the
0420          * list; we reduce that to 0 to make the object unavailable.
0421          */
0422         if (!refcount_dec_if_one(&conn->ref))
0423             continue;
0424         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_reap_service, 0, NULL);
0425
0426         if (rxrpc_conn_is_client(conn))
0427             BUG();
0428         else
0429             rxrpc_unpublish_service_conn(conn);
0430
0431         list_move_tail(&conn->link, &graveyard);
0432     }
0433     write_unlock(&rxnet->conn_lock);
0434
0435     if (earliest != now + MAX_JIFFY_OFFSET) {
0436         _debug("reschedule reaper %ld", (long)earliest - (long)now);
0437         ASSERT(time_after(earliest, now));
0438         rxrpc_set_service_reap_timer(rxnet, earliest);
0439     }
0440
0441     while (!list_empty(&graveyard)) {
0442         conn = list_entry(graveyard.next, struct rxrpc_connection,
0443                   link);
0444         list_del_init(&conn->link);
0445
0446         ASSERTCMP(refcount_read(&conn->ref), ==, 0);
0447         rxrpc_kill_connection(conn);
0448     }
0449
0450     _leave("");
0451 }
0452
0453 /*
0454  * preemptively destroy all the service connection records rather than
0455  * waiting for them to time out
0456  */
0457 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
0458 {
0459     struct rxrpc_connection *conn, *_p;
0460     bool leak = false;
0461
0462     _enter("");
0463
0464     atomic_dec(&rxnet->nr_conns);
0465     rxrpc_destroy_all_client_connections(rxnet);
0466
0467     del_timer_sync(&rxnet->service_conn_reap_timer);
0468     rxrpc_queue_work(&rxnet->service_conn_reaper);
0469     flush_workqueue(rxrpc_workqueue);
0470
0471     write_lock(&rxnet->conn_lock);
0472     list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
0473         pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
0474                conn, refcount_read(&conn->ref));
0475         leak = true;
0476     }
0477     write_unlock(&rxnet->conn_lock);
0478     BUG_ON(leak);
0479
0480     ASSERT(list_empty(&rxnet->conn_proc_list));
0481
0482     /* We need to wait for the connections to be destroyed by RCU as they
0483      * pin things that we still need to get rid of.
0484      */
0485     wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
0486     _leave("");
0487 }