Merge tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave...
[linux-2.6-microblaze.git] / net / rxrpc / conn_object.c
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                 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
45                 INIT_WORK(&conn->processor, &rxrpc_process_connection);
46                 INIT_LIST_HEAD(&conn->proc_link);
47                 INIT_LIST_HEAD(&conn->link);
48                 skb_queue_head_init(&conn->rx_queue);
49                 conn->security = &rxrpc_no_security;
50                 spin_lock_init(&conn->state_lock);
51                 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
52                 conn->idle_timestamp = jiffies;
53         }
54
55         _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
56         return conn;
57 }
58
59 /*
60  * Look up a connection in the cache by protocol parameters.
61  *
62  * If successful, a pointer to the connection is returned, but no ref is taken.
63  * NULL is returned if there is no match.
64  *
65  * When searching for a service call, if we find a peer but no connection, we
66  * return that through *_peer in case we need to create a new service call.
67  *
68  * The caller must be holding the RCU read lock.
69  */
70 struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
71                                                    struct sk_buff *skb,
72                                                    struct rxrpc_peer **_peer)
73 {
74         struct rxrpc_connection *conn;
75         struct rxrpc_conn_proto k;
76         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
77         struct sockaddr_rxrpc srx;
78         struct rxrpc_peer *peer;
79
80         _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
81
82         if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
83                 goto not_found;
84
85         if (srx.transport.family != local->srx.transport.family &&
86             (srx.transport.family == AF_INET &&
87              local->srx.transport.family != AF_INET6)) {
88                 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
89                                     srx.transport.family,
90                                     local->srx.transport.family);
91                 goto not_found;
92         }
93
94         k.epoch = sp->hdr.epoch;
95         k.cid   = sp->hdr.cid & RXRPC_CIDMASK;
96
97         if (rxrpc_to_server(sp)) {
98                 /* We need to look up service connections by the full protocol
99                  * parameter set.  We look up the peer first as an intermediate
100                  * step and then the connection from the peer's tree.
101                  */
102                 peer = rxrpc_lookup_peer_rcu(local, &srx);
103                 if (!peer)
104                         goto not_found;
105                 *_peer = peer;
106                 conn = rxrpc_find_service_conn_rcu(peer, skb);
107                 if (!conn || atomic_read(&conn->usage) == 0)
108                         goto not_found;
109                 _leave(" = %p", conn);
110                 return conn;
111         } else {
112                 /* Look up client connections by connection ID alone as their
113                  * IDs are unique for this machine.
114                  */
115                 conn = idr_find(&rxrpc_client_conn_ids,
116                                 sp->hdr.cid >> RXRPC_CIDSHIFT);
117                 if (!conn || atomic_read(&conn->usage) == 0) {
118                         _debug("no conn");
119                         goto not_found;
120                 }
121
122                 if (conn->proto.epoch != k.epoch ||
123                     conn->params.local != local)
124                         goto not_found;
125
126                 peer = conn->params.peer;
127                 switch (srx.transport.family) {
128                 case AF_INET:
129                         if (peer->srx.transport.sin.sin_port !=
130                             srx.transport.sin.sin_port ||
131                             peer->srx.transport.sin.sin_addr.s_addr !=
132                             srx.transport.sin.sin_addr.s_addr)
133                                 goto not_found;
134                         break;
135 #ifdef CONFIG_AF_RXRPC_IPV6
136                 case AF_INET6:
137                         if (peer->srx.transport.sin6.sin6_port !=
138                             srx.transport.sin6.sin6_port ||
139                             memcmp(&peer->srx.transport.sin6.sin6_addr,
140                                    &srx.transport.sin6.sin6_addr,
141                                    sizeof(struct in6_addr)) != 0)
142                                 goto not_found;
143                         break;
144 #endif
145                 default:
146                         BUG();
147                 }
148
149                 _leave(" = %p", conn);
150                 return conn;
151         }
152
153 not_found:
154         _leave(" = NULL");
155         return NULL;
156 }
157
158 /*
159  * Disconnect a call and clear any channel it occupies when that call
160  * terminates.  The caller must hold the channel_lock and must release the
161  * call's ref on the connection.
162  */
163 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
164                              struct rxrpc_call *call)
165 {
166         struct rxrpc_channel *chan =
167                 &conn->channels[call->cid & RXRPC_CHANNELMASK];
168
169         _enter("%d,%x", conn->debug_id, call->cid);
170
171         if (rcu_access_pointer(chan->call) == call) {
172                 /* Save the result of the call so that we can repeat it if necessary
173                  * through the channel, whilst disposing of the actual call record.
174                  */
175                 trace_rxrpc_disconnect_call(call);
176                 switch (call->completion) {
177                 case RXRPC_CALL_SUCCEEDED:
178                         chan->last_seq = call->rx_hard_ack;
179                         chan->last_type = RXRPC_PACKET_TYPE_ACK;
180                         break;
181                 case RXRPC_CALL_LOCALLY_ABORTED:
182                         chan->last_abort = call->abort_code;
183                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
184                         break;
185                 default:
186                         chan->last_abort = RX_USER_ABORT;
187                         chan->last_type = RXRPC_PACKET_TYPE_ABORT;
188                         break;
189                 }
190
191                 /* Sync with rxrpc_conn_retransmit(). */
192                 smp_wmb();
193                 chan->last_call = chan->call_id;
194                 chan->call_id = chan->call_counter;
195
196                 rcu_assign_pointer(chan->call, NULL);
197         }
198
199         _leave("");
200 }
201
202 /*
203  * Disconnect a call and clear any channel it occupies when that call
204  * terminates.
205  */
206 void rxrpc_disconnect_call(struct rxrpc_call *call)
207 {
208         struct rxrpc_connection *conn = call->conn;
209
210         call->peer->cong_cwnd = call->cong_cwnd;
211
212         if (!hlist_unhashed(&call->error_link)) {
213                 spin_lock_bh(&call->peer->lock);
214                 hlist_del_rcu(&call->error_link);
215                 spin_unlock_bh(&call->peer->lock);
216         }
217
218         if (rxrpc_is_client_call(call))
219                 return rxrpc_disconnect_client_call(conn->bundle, call);
220
221         spin_lock(&conn->bundle->channel_lock);
222         __rxrpc_disconnect_call(conn, call);
223         spin_unlock(&conn->bundle->channel_lock);
224
225         set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
226         conn->idle_timestamp = jiffies;
227 }
228
229 /*
230  * Kill off a connection.
231  */
232 void rxrpc_kill_connection(struct rxrpc_connection *conn)
233 {
234         struct rxrpc_net *rxnet = conn->params.local->rxnet;
235
236         ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
237                !rcu_access_pointer(conn->channels[1].call) &&
238                !rcu_access_pointer(conn->channels[2].call) &&
239                !rcu_access_pointer(conn->channels[3].call));
240         ASSERT(list_empty(&conn->cache_link));
241
242         write_lock(&rxnet->conn_lock);
243         list_del_init(&conn->proc_link);
244         write_unlock(&rxnet->conn_lock);
245
246         /* Drain the Rx queue.  Note that even though we've unpublished, an
247          * incoming packet could still be being added to our Rx queue, so we
248          * will need to drain it again in the RCU cleanup handler.
249          */
250         rxrpc_purge_queue(&conn->rx_queue);
251
252         /* Leave final destruction to RCU.  The connection processor work item
253          * must carry a ref on the connection to prevent us getting here whilst
254          * it is queued or running.
255          */
256         call_rcu(&conn->rcu, rxrpc_destroy_connection);
257 }
258
259 /*
260  * Queue a connection's work processor, getting a ref to pass to the work
261  * queue.
262  */
263 bool rxrpc_queue_conn(struct rxrpc_connection *conn)
264 {
265         const void *here = __builtin_return_address(0);
266         int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
267         if (n == 0)
268                 return false;
269         if (rxrpc_queue_work(&conn->processor))
270                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, n + 1, here);
271         else
272                 rxrpc_put_connection(conn);
273         return true;
274 }
275
276 /*
277  * Note the re-emergence of a connection.
278  */
279 void rxrpc_see_connection(struct rxrpc_connection *conn)
280 {
281         const void *here = __builtin_return_address(0);
282         if (conn) {
283                 int n = atomic_read(&conn->usage);
284
285                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_seen, n, here);
286         }
287 }
288
289 /*
290  * Get a ref on a connection.
291  */
292 struct rxrpc_connection *rxrpc_get_connection(struct rxrpc_connection *conn)
293 {
294         const void *here = __builtin_return_address(0);
295         int n = atomic_inc_return(&conn->usage);
296
297         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n, here);
298         return conn;
299 }
300
301 /*
302  * Try to get a ref on a connection.
303  */
304 struct rxrpc_connection *
305 rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
306 {
307         const void *here = __builtin_return_address(0);
308
309         if (conn) {
310                 int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
311                 if (n > 0)
312                         trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n + 1, here);
313                 else
314                         conn = NULL;
315         }
316         return conn;
317 }
318
319 /*
320  * Set the service connection reap timer.
321  */
322 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
323                                          unsigned long reap_at)
324 {
325         if (rxnet->live)
326                 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
327 }
328
329 /*
330  * Release a service connection
331  */
332 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
333 {
334         const void *here = __builtin_return_address(0);
335         unsigned int debug_id = conn->debug_id;
336         int n;
337
338         n = atomic_dec_return(&conn->usage);
339         trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, n, here);
340         ASSERTCMP(n, >=, 0);
341         if (n == 1)
342                 rxrpc_set_service_reap_timer(conn->params.local->rxnet,
343                                              jiffies + rxrpc_connection_expiry);
344 }
345
346 /*
347  * destroy a virtual connection
348  */
349 static void rxrpc_destroy_connection(struct rcu_head *rcu)
350 {
351         struct rxrpc_connection *conn =
352                 container_of(rcu, struct rxrpc_connection, rcu);
353
354         _enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
355
356         ASSERTCMP(atomic_read(&conn->usage), ==, 0);
357
358         _net("DESTROY CONN %d", conn->debug_id);
359
360         del_timer_sync(&conn->timer);
361         rxrpc_purge_queue(&conn->rx_queue);
362
363         conn->security->clear(conn);
364         key_put(conn->params.key);
365         rxrpc_put_bundle(conn->bundle);
366         rxrpc_put_peer(conn->params.peer);
367
368         if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
369                 wake_up_var(&conn->params.local->rxnet->nr_conns);
370         rxrpc_put_local(conn->params.local);
371
372         kfree(conn);
373         _leave("");
374 }
375
376 /*
377  * reap dead service connections
378  */
379 void rxrpc_service_connection_reaper(struct work_struct *work)
380 {
381         struct rxrpc_connection *conn, *_p;
382         struct rxrpc_net *rxnet =
383                 container_of(work, struct rxrpc_net, service_conn_reaper);
384         unsigned long expire_at, earliest, idle_timestamp, now;
385
386         LIST_HEAD(graveyard);
387
388         _enter("");
389
390         now = jiffies;
391         earliest = now + MAX_JIFFY_OFFSET;
392
393         write_lock(&rxnet->conn_lock);
394         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
395                 ASSERTCMP(atomic_read(&conn->usage), >, 0);
396                 if (likely(atomic_read(&conn->usage) > 1))
397                         continue;
398                 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
399                         continue;
400
401                 if (rxnet->live && !conn->params.local->dead) {
402                         idle_timestamp = READ_ONCE(conn->idle_timestamp);
403                         expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
404                         if (conn->params.local->service_closed)
405                                 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
406
407                         _debug("reap CONN %d { u=%d,t=%ld }",
408                                conn->debug_id, atomic_read(&conn->usage),
409                                (long)expire_at - (long)now);
410
411                         if (time_before(now, expire_at)) {
412                                 if (time_before(expire_at, earliest))
413                                         earliest = expire_at;
414                                 continue;
415                         }
416                 }
417
418                 /* The usage count sits at 1 whilst the object is unused on the
419                  * list; we reduce that to 0 to make the object unavailable.
420                  */
421                 if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
422                         continue;
423                 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_reap_service, 0, NULL);
424
425                 if (rxrpc_conn_is_client(conn))
426                         BUG();
427                 else
428                         rxrpc_unpublish_service_conn(conn);
429
430                 list_move_tail(&conn->link, &graveyard);
431         }
432         write_unlock(&rxnet->conn_lock);
433
434         if (earliest != now + MAX_JIFFY_OFFSET) {
435                 _debug("reschedule reaper %ld", (long)earliest - (long)now);
436                 ASSERT(time_after(earliest, now));
437                 rxrpc_set_service_reap_timer(rxnet, earliest);
438         }
439
440         while (!list_empty(&graveyard)) {
441                 conn = list_entry(graveyard.next, struct rxrpc_connection,
442                                   link);
443                 list_del_init(&conn->link);
444
445                 ASSERTCMP(atomic_read(&conn->usage), ==, 0);
446                 rxrpc_kill_connection(conn);
447         }
448
449         _leave("");
450 }
451
452 /*
453  * preemptively destroy all the service connection records rather than
454  * waiting for them to time out
455  */
456 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
457 {
458         struct rxrpc_connection *conn, *_p;
459         bool leak = false;
460
461         _enter("");
462
463         atomic_dec(&rxnet->nr_conns);
464         rxrpc_destroy_all_client_connections(rxnet);
465
466         del_timer_sync(&rxnet->service_conn_reap_timer);
467         rxrpc_queue_work(&rxnet->service_conn_reaper);
468         flush_workqueue(rxrpc_workqueue);
469
470         write_lock(&rxnet->conn_lock);
471         list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
472                 pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
473                        conn, atomic_read(&conn->usage));
474                 leak = true;
475         }
476         write_unlock(&rxnet->conn_lock);
477         BUG_ON(leak);
478
479         ASSERT(list_empty(&rxnet->conn_proc_list));
480
481         /* We need to wait for the connections to be destroyed by RCU as they
482          * pin things that we still need to get rid of.
483          */
484         wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
485         _leave("");
486 }