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_clean_up_connection(struct work_struct *work);
23 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
24 unsigned long reap_at);
25
26 void rxrpc_poke_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
27 {
28 struct rxrpc_local *local = conn->local;
29 bool busy;
30
31 if (WARN_ON_ONCE(!local))
32 return;
33
34 spin_lock_bh(&local->lock);
35 busy = !list_empty(&conn->attend_link);
36 if (!busy) {
37 rxrpc_get_connection(conn, why);
38 list_add_tail(&conn->attend_link, &local->conn_attend_q);
39 }
40 spin_unlock_bh(&local->lock);
41 rxrpc_wake_up_io_thread(local);
42 }
43
44 static void rxrpc_connection_timer(struct timer_list *timer)
45 {
46 struct rxrpc_connection *conn =
47 container_of(timer, struct rxrpc_connection, timer);
48
49 rxrpc_poke_conn(conn, rxrpc_conn_get_poke_timer);
50 }
51
52 /*
53 * allocate a new connection
54 */
55 struct rxrpc_connection *rxrpc_alloc_connection(struct rxrpc_net *rxnet,
56 gfp_t gfp)
57 {
58 struct rxrpc_connection *conn;
59
60 _enter("");
61
62 conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
63 if (conn) {
64 INIT_LIST_HEAD(&conn->cache_link);
65 timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
66 INIT_WORK(&conn->processor, rxrpc_process_connection);
67 INIT_WORK(&conn->destructor, rxrpc_clean_up_connection);
68 INIT_LIST_HEAD(&conn->proc_link);
69 INIT_LIST_HEAD(&conn->link);
70 mutex_init(&conn->security_lock);
71 mutex_init(&conn->tx_data_alloc_lock);
72 skb_queue_head_init(&conn->rx_queue);
73 conn->rxnet = rxnet;
74 conn->security = &rxrpc_no_security;
75 spin_lock_init(&conn->state_lock);
76 conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
77 conn->idle_timestamp = jiffies;
78 }
79
80 _leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
81 return conn;
82 }
83
84 /*
85 * Look up a connection in the cache by protocol parameters.
86 *
87 * If successful, a pointer to the connection is returned, but no ref is taken.
88 * NULL is returned if there is no match.
89 *
90 * When searching for a service call, if we find a peer but no connection, we
91 * return that through *_peer in case we need to create a new service call.
92 *
93 * The caller must be holding the RCU read lock.
94 */
95 struct rxrpc_connection *rxrpc_find_client_connection_rcu(struct rxrpc_local *local,
96 struct sockaddr_rxrpc *srx,
97 struct sk_buff *skb)
98 {
99 struct rxrpc_connection *conn;
100 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
101 struct rxrpc_peer *peer;
102
103 _enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
104
105 /* Look up client connections by connection ID alone as their
106 * IDs are unique for this machine.
107 */
108 conn = idr_find(&local->conn_ids, sp->hdr.cid >> RXRPC_CIDSHIFT);
109 if (!conn || refcount_read(&conn->ref) == 0) {
110 _debug("no conn");
111 goto not_found;
112 }
113
114 if (conn->proto.epoch != sp->hdr.epoch ||
115 conn->local != local)
116 goto not_found;
117
118 peer = conn->peer;
119 switch (srx->transport.family) {
120 case AF_INET:
121 if (peer->srx.transport.sin.sin_port !=
122 srx->transport.sin.sin_port)
123 goto not_found;
124 break;
125 #ifdef CONFIG_AF_RXRPC_IPV6
126 case AF_INET6:
127 if (peer->srx.transport.sin6.sin6_port !=
128 srx->transport.sin6.sin6_port)
129 goto not_found;
130 break;
131 #endif
132 default:
133 BUG();
134 }
135
136 _leave(" = %p", conn);
137 return conn;
138
139 not_found:
140 _leave(" = NULL");
141 return NULL;
142 }
143
144 /*
145 * Disconnect a call and clear any channel it occupies when that call
146 * terminates. The caller must hold the channel_lock and must release the
147 * call's ref on the connection.
148 */
149 void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
150 struct rxrpc_call *call)
151 {
152 struct rxrpc_channel *chan =
153 &conn->channels[call->cid & RXRPC_CHANNELMASK];
154
155 _enter("%d,%x", conn->debug_id, call->cid);
156
157 if (chan->call == call) {
158 /* Save the result of the call so that we can repeat it if necessary
159 * through the channel, whilst disposing of the actual call record.
160 */
161 trace_rxrpc_disconnect_call(call);
162 switch (call->completion) {
163 case RXRPC_CALL_SUCCEEDED:
164 chan->last_seq = call->rx_highest_seq;
165 chan->last_type = RXRPC_PACKET_TYPE_ACK;
166 break;
167 case RXRPC_CALL_LOCALLY_ABORTED:
168 chan->last_abort = call->abort_code;
169 chan->last_type = RXRPC_PACKET_TYPE_ABORT;
170 break;
171 default:
172 chan->last_abort = RX_CALL_DEAD;
173 chan->last_type = RXRPC_PACKET_TYPE_ABORT;
174 break;
175 }
176
177 chan->last_call = chan->call_id;
178 chan->call_id = chan->call_counter;
179 chan->call = NULL;
180 }
181
182 _leave("");
183 }
184
185 /*
186 * Disconnect a call and clear any channel it occupies when that call
187 * terminates.
188 */
189 void rxrpc_disconnect_call(struct rxrpc_call *call)
190 {
191 struct rxrpc_connection *conn = call->conn;
192
193 set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
194 rxrpc_see_call(call, rxrpc_call_see_disconnected);
195
196 call->peer->cong_ssthresh = call->cong_ssthresh;
197
198 if (!hlist_unhashed(&call->error_link)) {
199 spin_lock(&call->peer->lock);
200 hlist_del_init(&call->error_link);
201 spin_unlock(&call->peer->lock);
202 }
203
204 if (rxrpc_is_client_call(call)) {
205 rxrpc_disconnect_client_call(call->bundle, call);
206 } else {
207 __rxrpc_disconnect_call(conn, call);
208 conn->idle_timestamp = jiffies;
209 if (atomic_dec_and_test(&conn->active))
210 rxrpc_set_service_reap_timer(conn->rxnet,
211 jiffies + rxrpc_connection_expiry * HZ);
212 }
213
214 rxrpc_put_call(call, rxrpc_call_put_io_thread);
215 }
216
217 /*
218 * Queue a connection's work processor, getting a ref to pass to the work
219 * queue.
220 */
221 void rxrpc_queue_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
222 {
223 if (atomic_read(&conn->active) >= 0 &&
224 rxrpc_queue_work(&conn->processor))
225 rxrpc_see_connection(conn, why);
226 }
227
228 /*
229 * Note the re-emergence of a connection.
230 */
231 void rxrpc_see_connection(struct rxrpc_connection *conn,
232 enum rxrpc_conn_trace why)
233 {
234 if (conn) {
235 int r = refcount_read(&conn->ref);
236
237 trace_rxrpc_conn(conn->debug_id, r, why);
238 }
239 }
240
241 /*
242 * Get a ref on a connection.
243 */
244 struct rxrpc_connection *rxrpc_get_connection(struct rxrpc_connection *conn,
245 enum rxrpc_conn_trace why)
246 {
247 int r;
248
249 __refcount_inc(&conn->ref, &r);
250 trace_rxrpc_conn(conn->debug_id, r + 1, why);
251 return conn;
252 }
253
254 /*
255 * Try to get a ref on a connection.
256 */
257 struct rxrpc_connection *
258 rxrpc_get_connection_maybe(struct rxrpc_connection *conn,
259 enum rxrpc_conn_trace why)
260 {
261 int r;
262
263 if (conn) {
264 if (__refcount_inc_not_zero(&conn->ref, &r))
265 trace_rxrpc_conn(conn->debug_id, r + 1, why);
266 else
267 conn = NULL;
268 }
269 return conn;
270 }
271
272 /*
273 * Set the service connection reap timer.
274 */
275 static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
276 unsigned long reap_at)
277 {
278 if (rxnet->live)
279 timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
280 }
281
282 /*
283 * destroy a virtual connection
284 */
285 static void rxrpc_rcu_free_connection(struct rcu_head *rcu)
286 {
287 struct rxrpc_connection *conn =
288 container_of(rcu, struct rxrpc_connection, rcu);
289 struct rxrpc_net *rxnet = conn->rxnet;
290
291 _enter("{%d,u=%d}", conn->debug_id, refcount_read(&conn->ref));
292
293 trace_rxrpc_conn(conn->debug_id, refcount_read(&conn->ref),
294 rxrpc_conn_free);
295 kfree(conn);
296
297 if (atomic_dec_and_test(&rxnet->nr_conns))
298 wake_up_var(&rxnet->nr_conns);
299 }
300
301 /*
302 * Clean up a dead connection.
303 */
304 static void rxrpc_clean_up_connection(struct work_struct *work)
305 {
306 struct rxrpc_connection *conn =
307 container_of(work, struct rxrpc_connection, destructor);
308 struct rxrpc_net *rxnet = conn->rxnet;
309
310 ASSERT(!conn->channels[0].call &&
311 !conn->channels[1].call &&
312 !conn->channels[2].call &&
313 !conn->channels[3].call);
314 ASSERT(list_empty(&conn->cache_link));
315
316 del_timer_sync(&conn->timer);
317 cancel_work_sync(&conn->processor); /* Processing may restart the timer */
318 del_timer_sync(&conn->timer);
319
320 write_lock(&rxnet->conn_lock);
321 list_del_init(&conn->proc_link);
322 write_unlock(&rxnet->conn_lock);
323
324 rxrpc_purge_queue(&conn->rx_queue);
325
326 rxrpc_kill_client_conn(conn);
327
328 conn->security->clear(conn);
329 key_put(conn->key);
330 rxrpc_put_bundle(conn->bundle, rxrpc_bundle_put_conn);
331 rxrpc_put_peer(conn->peer, rxrpc_peer_put_conn);
332 rxrpc_put_local(conn->local, rxrpc_local_put_kill_conn);
333
334 /* Drain the Rx queue. Note that even though we've unpublished, an
335 * incoming packet could still be being added to our Rx queue, so we
336 * will need to drain it again in the RCU cleanup handler.
337 */
338 rxrpc_purge_queue(&conn->rx_queue);
339
340 if (conn->tx_data_alloc.va)
341 __page_frag_cache_drain(virt_to_page(conn->tx_data_alloc.va),
342 conn->tx_data_alloc.pagecnt_bias);
343 call_rcu(&conn->rcu, rxrpc_rcu_free_connection);
344 }
345
346 /*
347 * Drop a ref on a connection.
348 */
349 void rxrpc_put_connection(struct rxrpc_connection *conn,
350 enum rxrpc_conn_trace why)
351 {
352 unsigned int debug_id;
353 bool dead;
354 int r;
355
356 if (!conn)
357 return;
358
359 debug_id = conn->debug_id;
360 dead = __refcount_dec_and_test(&conn->ref, &r);
361 trace_rxrpc_conn(debug_id, r - 1, why);
362 if (dead) {
363 del_timer(&conn->timer);
364 cancel_work(&conn->processor);
365
366 if (in_softirq() || work_busy(&conn->processor) ||
367 timer_pending(&conn->timer))
368 /* Can't use the rxrpc workqueue as we need to cancel/flush
369 * something that may be running/waiting there.
370 */
371 schedule_work(&conn->destructor);
372 else
373 rxrpc_clean_up_connection(&conn->destructor);
374 }
375 }
376
377 /*
378 * reap dead service connections
379 */
380 void rxrpc_service_connection_reaper(struct work_struct *work)
381 {
382 struct rxrpc_connection *conn, *_p;
383 struct rxrpc_net *rxnet =
384 container_of(work, struct rxrpc_net, service_conn_reaper);
385 unsigned long expire_at, earliest, idle_timestamp, now;
386 int active;
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->active), >=, 0);
398 if (likely(atomic_read(&conn->active) > 0))
399 continue;
400 if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
401 continue;
402
403 if (rxnet->live && !conn->local->dead) {
404 idle_timestamp = READ_ONCE(conn->idle_timestamp);
405 expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
406 if (conn->local->service_closed)
407 expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
408
409 _debug("reap CONN %d { a=%d,t=%ld }",
410 conn->debug_id, atomic_read(&conn->active),
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 activity count sits at 0 whilst the conn is unused on
421 * the list; we reduce that to -1 to make the conn unavailable.
422 */
423 active = 0;
424 if (!atomic_try_cmpxchg(&conn->active, &active, -1))
425 continue;
426 rxrpc_see_connection(conn, rxrpc_conn_see_reap_service);
427
428 if (rxrpc_conn_is_client(conn))
429 BUG();
430 else
431 rxrpc_unpublish_service_conn(conn);
432
433 list_move_tail(&conn->link, &graveyard);
434 }
435 write_unlock(&rxnet->conn_lock);
436
437 if (earliest != now + MAX_JIFFY_OFFSET) {
438 _debug("reschedule reaper %ld", (long)earliest - (long)now);
439 ASSERT(time_after(earliest, now));
440 rxrpc_set_service_reap_timer(rxnet, earliest);
441 }
442
443 while (!list_empty(&graveyard)) {
444 conn = list_entry(graveyard.next, struct rxrpc_connection,
445 link);
446 list_del_init(&conn->link);
447
448 ASSERTCMP(atomic_read(&conn->active), ==, -1);
449 rxrpc_put_connection(conn, rxrpc_conn_put_service_reaped);
450 }
451
452 _leave("");
453 }
454
455 /*
456 * preemptively destroy all the service connection records rather than
457 * waiting for them to time out
458 */
459 void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
460 {
461 struct rxrpc_connection *conn, *_p;
462 bool leak = false;
463
464 _enter("");
465
466 atomic_dec(&rxnet->nr_conns);
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, refcount_read(&conn->ref));
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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