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Linux/net/rxrpc/conn_object.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /* RxRPC virtual connection handler, common bits.
  3  *
  4  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
  5  * Written by David Howells (dhowells@redhat.com)
  6  */
  7 
  8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  9 
 10 #include <linux/module.h>
 11 #include <linux/slab.h>
 12 #include <linux/net.h>
 13 #include <linux/skbuff.h>
 14 #include "ar-internal.h"
 15 
 16 /*
 17  * Time till a connection expires after last use (in seconds).
 18  */
 19 unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
 20 unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
 21 
 22 static void rxrpc_destroy_connection(struct rcu_head *);
 23 
 24 static void rxrpc_connection_timer(struct timer_list *timer)
 25 {
 26         struct rxrpc_connection *conn =
 27                 container_of(timer, struct rxrpc_connection, timer);
 28 
 29         rxrpc_queue_conn(conn);
 30 }
 31 
 32 /*
 33  * allocate a new connection
 34  */
 35 struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
 36 {
 37         struct rxrpc_connection *conn;
 38 
 39         _enter("");
 40 
 41         conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
 42         if (conn) {
 43                 INIT_LIST_HEAD(&conn->cache_link);
 44                 spin_lock_init(&conn->channel_lock);
 45                 INIT_LIST_HEAD(&conn->waiting_calls);
 46                 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
 47                 INIT_WORK(&conn->processor, &rxrpc_process_connection);
 48                 INIT_LIST_HEAD(&conn->proc_link);
 49                 INIT_LIST_HEAD(&conn->link);
 50                 skb_queue_head_init(&conn->rx_queue);
 51                 conn->security = &rxrpc_no_security;
 52                 spin_lock_init(&conn->state_lock);
 53                 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
 54                 conn->size_align = 4;
 55                 conn->idle_timestamp = jiffies;
 56         }
 57 
 58         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
 59         return conn;
 60 }
 61 
 62 /*
 63  * Look up a connection in the cache by protocol parameters.
 64  *
 65  * If successful, a pointer to the connection is returned, but no ref is taken.
 66  * NULL is returned if there is no match.
 67  *
 68  * When searching for a service call, if we find a peer but no connection, we
 69  * return that through *_peer in case we need to create a new service call.
 70  *
 71  * The caller must be holding the RCU read lock.
 72  */
 73 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
 74                                                    struct sk_buff *skb,
 75                                                    struct rxrpc_peer **_peer)
 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(&srx, skb) < 0)
 86                 goto not_found;
 87 
 88         if (srx.transport.family != local->srx.transport.family &&
 89             (srx.transport.family == AF_INET &&
 90              local->srx.transport.family != AF_INET6)) {
 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 (rxrpc_to_server(sp)) {
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                 *_peer = peer;
109                 conn = rxrpc_find_service_conn_rcu(peer, skb);
110                 if (!conn || atomic_read(&conn->usage) == 0)
111                         goto not_found;
112                 _leave(" = %p", conn);
113                 return conn;
114         } else {
115                 /* Look up client connections by connection ID alone as their
116                  * IDs are unique for this machine.
117                  */
118                 conn = idr_find(&rxrpc_client_conn_ids,
119                                 sp->hdr.cid >> RXRPC_CIDSHIFT);
120                 if (!conn || atomic_read(&conn->usage) == 0) {
121                         _debug("no conn");
122                         goto not_found;
123                 }
124 
125                 if (conn->proto.epoch != k.epoch ||
126                     conn->params.local != local)
127                         goto not_found;
128 
129                 peer = conn->params.peer;
130                 switch (srx.transport.family) {
131                 case AF_INET:
132                         if (peer->srx.transport.sin.sin_port !=
133                             srx.transport.sin.sin_port ||
134                             peer->srx.transport.sin.sin_addr.s_addr !=
135                             srx.transport.sin.sin_addr.s_addr)
136                                 goto not_found;
137                         break;
138 #ifdef CONFIG_AF_RXRPC_IPV6
139                 case AF_INET6:
140                         if (peer->srx.transport.sin6.sin6_port !=
141                             srx.transport.sin6.sin6_port ||
142                             memcmp(&peer->srx.transport.sin6.sin6_addr,
143                                    &srx.transport.sin6.sin6_addr,
144                                    sizeof(struct in6_addr)) != 0)
145                                 goto not_found;
146                         break;
147 #endif
148                 default:
149                         BUG();
150                 }
151 
152                 _leave(" = %p", conn);
153                 return conn;
154         }
155 
156 not_found:
157         _leave(" = NULL");
158         return NULL;
159 }
160 
161 /*
162  * Disconnect a call and clear any channel it occupies when that call
163  * terminates.  The caller must hold the channel_lock and must release the
164  * call's ref on the connection.
165  */
166 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
167                              struct rxrpc_call *call)
168 {
169         struct rxrpc_channel *chan =
170                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
171 
172         _enter("%d,%x", conn->debug_id, call->cid);
173 
174         if (rcu_access_pointer(chan->call) == call) {
175                 /* Save the result of the call so that we can repeat it if necessary
176                  * through the channel, whilst disposing of the actual call record.
177                  */
178                 trace_rxrpc_disconnect_call(call);
179                 switch (call->completion) {
180                 case RXRPC_CALL_SUCCEEDED:
181                         chan->last_seq = call->rx_hard_ack;
182                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
183                         break;
184                 case RXRPC_CALL_LOCALLY_ABORTED:
185                         chan->last_abort = call->abort_code;
186                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
187                         break;
188                 default:
189                         chan->last_abort = RX_USER_ABORT;
190                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
191                         break;
192                 }
193 
194                 /* Sync with rxrpc_conn_retransmit(). */
195                 smp_wmb();
196                 chan->last_call = chan->call_id;
197                 chan->call_id = chan->call_counter;
198 
199                 rcu_assign_pointer(chan->call, NULL);
200         }
201 
202         _leave("");
203 }
204 
205 /*
206  * Disconnect a call and clear any channel it occupies when that call
207  * terminates.
208  */
209 void rxrpc_disconnect_call(struct rxrpc_call *call)
210 {
211         struct rxrpc_connection *conn = call->conn;
212 
213         call->peer->cong_cwnd = call->cong_cwnd;
214 
215         if (!hlist_unhashed(&call->error_link)) {
216                 spin_lock_bh(&call->peer->lock);
217                 hlist_del_rcu(&call->error_link);
218                 spin_unlock_bh(&call->peer->lock);
219         }
220 
221         if (rxrpc_is_client_call(call))
222                 return rxrpc_disconnect_client_call(call);
223 
224         spin_lock(&conn->channel_lock);
225         __rxrpc_disconnect_call(conn, call);
226         spin_unlock(&conn->channel_lock);
227 
228         set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
229         conn->idle_timestamp = jiffies;
230 }
231 
232 /*
233  * Kill off a connection.
234  */
235 void rxrpc_kill_connection(struct rxrpc_connection *conn)
236 {
237         struct rxrpc_net *rxnet = conn->params.local->rxnet;
238 
239         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
240                !rcu_access_pointer(conn->channels[1].call) &&
241                !rcu_access_pointer(conn->channels[2].call) &&
242                !rcu_access_pointer(conn->channels[3].call));
243         ASSERT(list_empty(&conn->cache_link));
244 
245         write_lock(&rxnet->conn_lock);
246         list_del_init(&conn->proc_link);
247         write_unlock(&rxnet->conn_lock);
248 
249         /* Drain the Rx queue.  Note that even though we've unpublished, an
250          * incoming packet could still be being added to our Rx queue, so we
251          * will need to drain it again in the RCU cleanup handler.
252          */
253         rxrpc_purge_queue(&conn->rx_queue);
254 
255         /* Leave final destruction to RCU.  The connection processor work item
256          * must carry a ref on the connection to prevent us getting here whilst
257          * it is queued or running.
258          */
259         call_rcu(&conn->rcu, rxrpc_destroy_connection);
260 }
261 
262 /*
263  * Queue a connection's work processor, getting a ref to pass to the work
264  * queue.
265  */
266 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
267 {
268         const void *here = __builtin_return_address(0);
269         int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
270         if (n == 0)
271                 return false;
272         if (rxrpc_queue_work(&conn->processor))
273                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, n + 1, here);
274         else
275                 rxrpc_put_connection(conn);
276         return true;
277 }
278 
279 /*
280  * Note the re-emergence of a connection.
281  */
282 void rxrpc_see_connection(struct rxrpc_connection *conn)
283 {
284         const void *here = __builtin_return_address(0);
285         if (conn) {
286                 int n = atomic_read(&conn->usage);
287 
288                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_seen, n, here);
289         }
290 }
291 
292 /*
293  * Get a ref on a connection.
294  */
295 void rxrpc_get_connection(struct rxrpc_connection *conn)
296 {
297         const void *here = __builtin_return_address(0);
298         int n = atomic_inc_return(&conn->usage);
299 
300         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n, here);
301 }
302 
303 /*
304  * Try to get a ref on a connection.
305  */
306 struct rxrpc_connection *
307 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
308 {
309         const void *here = __builtin_return_address(0);
310 
311         if (conn) {
312                 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
313                 if (n > 0)
314                         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n + 1, here);
315                 else
316                         conn = NULL;
317         }
318         return conn;
319 }
320 
321 /*
322  * Set the service connection reap timer.
323  */
324 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
325                                          unsigned long reap_at)
326 {
327         if (rxnet->live)
328                 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
329 }
330 
331 /*
332  * Release a service connection
333  */
334 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
335 {
336         const void *here = __builtin_return_address(0);
337         unsigned int debug_id = conn->debug_id;
338         int n;
339 
340         n = atomic_dec_return(&conn->usage);
341         trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, n, here);
342         ASSERTCMP(n, >=, 0);
343         if (n == 1)
344                 rxrpc_set_service_reap_timer(conn->params.local->rxnet,
345                                              jiffies + rxrpc_connection_expiry);
346 }
347 
348 /*
349  * destroy a virtual connection
350  */
351 static void rxrpc_destroy_connection(struct rcu_head *rcu)
352 {
353         struct rxrpc_connection *conn =
354                 container_of(rcu, struct rxrpc_connection, rcu);
355 
356         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
357 
358         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
359 
360         _net("DESTROY CONN %d", conn->debug_id);
361 
362         del_timer_sync(&conn->timer);
363         rxrpc_purge_queue(&conn->rx_queue);
364 
365         conn->security->clear(conn);
366         key_put(conn->params.key);
367         key_put(conn->server_key);
368         rxrpc_put_peer(conn->params.peer);
369 
370         if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
371                 wake_up_var(&conn->params.local->rxnet->nr_conns);
372         rxrpc_put_local(conn->params.local);
373 
374         kfree(conn);
375         _leave("");
376 }
377 
378 /*
379  * reap dead service connections
380  */
381 void rxrpc_service_connection_reaper(struct work_struct *work)
382 {
383         struct rxrpc_connection *conn, *_p;
384         struct rxrpc_net *rxnet =
385                 container_of(work, struct rxrpc_net, service_conn_reaper);
386         unsigned long expire_at, earliest, idle_timestamp, now;
387 
388         LIST_HEAD(graveyard);
389 
390         _enter("");
391 
392         now = jiffies;
393         earliest = now + MAX_JIFFY_OFFSET;
394 
395         write_lock(&rxnet->conn_lock);
396         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
397                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
398                 if (likely(atomic_read(&conn->usage) > 1))
399                         continue;
400                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
401                         continue;
402 
403                 if (rxnet->live && !conn->params.local->dead) {
404                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
405                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
406                         if (conn->params.local->service_closed)
407                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
408 
409                         _debug("reap CONN %d { u=%d,t=%ld }",
410                                conn->debug_id, atomic_read(&conn->usage),
411                                (long)expire_at - (long)now);
412 
413                         if (time_before(now, expire_at)) {
414                                 if (time_before(expire_at, earliest))
415                                         earliest = expire_at;
416                                 continue;
417                         }
418                 }
419 
420                 /* The usage count sits at 1 whilst the object is unused on the
421                  * list; we reduce that to 0 to make the object unavailable.
422                  */
423                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
424                         continue;
425                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_reap_service, 0, NULL);
426 
427                 if (rxrpc_conn_is_client(conn))
428                         BUG();
429                 else
430                         rxrpc_unpublish_service_conn(conn);
431 
432                 list_move_tail(&conn->link, &graveyard);
433         }
434         write_unlock(&rxnet->conn_lock);
435 
436         if (earliest != now + MAX_JIFFY_OFFSET) {
437                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
438                 ASSERT(time_after(earliest, now));
439                 rxrpc_set_service_reap_timer(rxnet, earliest);
440         }
441 
442         while (!list_empty(&graveyard)) {
443                 conn = list_entry(graveyard.next, struct rxrpc_connection,
444                                   link);
445                 list_del_init(&conn->link);
446 
447                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
448                 rxrpc_kill_connection(conn);
449         }
450 
451         _leave("");
452 }
453 
454 /*
455  * preemptively destroy all the service connection records rather than
456  * waiting for them to time out
457  */
458 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
459 {
460         struct rxrpc_connection *conn, *_p;
461         bool leak = false;
462 
463         _enter("");
464 
465         atomic_dec(&rxnet->nr_conns);
466         rxrpc_destroy_all_client_connections(rxnet);
467 
468         del_timer_sync(&rxnet->service_conn_reap_timer);
469         rxrpc_queue_work(&rxnet->service_conn_reaper);
470         flush_workqueue(rxrpc_workqueue);
471 
472         write_lock(&rxnet->conn_lock);
473         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
474                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
475                        conn, atomic_read(&conn->usage));
476                 leak = true;
477         }
478         write_unlock(&rxnet->conn_lock);
479         BUG_ON(leak);
480 
481         ASSERT(list_empty(&rxnet->conn_proc_list));
482 
483         /* We need to wait for the connections to be destroyed by RCU as they
484          * pin things that we still need to get rid of.
485          */
486         wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
487         _leave("");
488 }
489 

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