summaryrefslogtreecommitdiff
path: root/net/rxrpc/conn_object.c
blob: 1539d315afe74ace265dd7ac32ffc7031d0b2323 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
// SPDX-License-Identifier: GPL-2.0-or-later
/* RxRPC virtual connection handler, common bits.
 *
 * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include "ar-internal.h"

/*
 * Time till a connection expires after last use (in seconds).
 */
unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;

static void rxrpc_clean_up_connection(struct work_struct *work);
static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
					 unsigned long reap_at);

void rxrpc_poke_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
{
	struct rxrpc_local *local = conn->local;
	bool busy;

	if (WARN_ON_ONCE(!local))
		return;

	spin_lock_bh(&local->lock);
	busy = !list_empty(&conn->attend_link);
	if (!busy) {
		rxrpc_get_connection(conn, why);
		list_add_tail(&conn->attend_link, &local->conn_attend_q);
	}
	spin_unlock_bh(&local->lock);
	rxrpc_wake_up_io_thread(local);
}

static void rxrpc_connection_timer(struct timer_list *timer)
{
	struct rxrpc_connection *conn =
		container_of(timer, struct rxrpc_connection, timer);

	rxrpc_poke_conn(conn, rxrpc_conn_get_poke_timer);
}

/*
 * allocate a new connection
 */
struct rxrpc_connection *rxrpc_alloc_connection(struct rxrpc_net *rxnet,
						gfp_t gfp)
{
	struct rxrpc_connection *conn;

	_enter("");

	conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
	if (conn) {
		INIT_LIST_HEAD(&conn->cache_link);
		timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
		INIT_WORK(&conn->processor, rxrpc_process_connection);
		INIT_WORK(&conn->destructor, rxrpc_clean_up_connection);
		INIT_LIST_HEAD(&conn->proc_link);
		INIT_LIST_HEAD(&conn->link);
		mutex_init(&conn->security_lock);
		mutex_init(&conn->tx_data_alloc_lock);
		skb_queue_head_init(&conn->rx_queue);
		conn->rxnet = rxnet;
		conn->security = &rxrpc_no_security;
		spin_lock_init(&conn->state_lock);
		conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
		conn->idle_timestamp = jiffies;
	}

	_leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
	return conn;
}

/*
 * Look up a connection in the cache by protocol parameters.
 *
 * If successful, a pointer to the connection is returned, but no ref is taken.
 * NULL is returned if there is no match.
 *
 * When searching for a service call, if we find a peer but no connection, we
 * return that through *_peer in case we need to create a new service call.
 *
 * The caller must be holding the RCU read lock.
 */
struct rxrpc_connection *rxrpc_find_client_connection_rcu(struct rxrpc_local *local,
							  struct sockaddr_rxrpc *srx,
							  struct sk_buff *skb)
{
	struct rxrpc_connection *conn;
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	struct rxrpc_peer *peer;

	_enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);

	/* Look up client connections by connection ID alone as their
	 * IDs are unique for this machine.
	 */
	conn = idr_find(&local->conn_ids, sp->hdr.cid >> RXRPC_CIDSHIFT);
	if (!conn || refcount_read(&conn->ref) == 0) {
		_debug("no conn");
		goto not_found;
	}

	if (conn->proto.epoch != sp->hdr.epoch ||
	    conn->local != local)
		goto not_found;

	peer = conn->peer;
	switch (srx->transport.family) {
	case AF_INET:
		if (peer->srx.transport.sin.sin_port !=
		    srx->transport.sin.sin_port)
			goto not_found;
		break;
#ifdef CONFIG_AF_RXRPC_IPV6
	case AF_INET6:
		if (peer->srx.transport.sin6.sin6_port !=
		    srx->transport.sin6.sin6_port)
			goto not_found;
		break;
#endif
	default:
		BUG();
	}

	_leave(" = %p", conn);
	return conn;

not_found:
	_leave(" = NULL");
	return NULL;
}

/*
 * Disconnect a call and clear any channel it occupies when that call
 * terminates.  The caller must hold the channel_lock and must release the
 * call's ref on the connection.
 */
void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
			     struct rxrpc_call *call)
{
	struct rxrpc_channel *chan =
		&conn->channels[call->cid & RXRPC_CHANNELMASK];

	_enter("%d,%x", conn->debug_id, call->cid);

	if (chan->call == call) {
		/* Save the result of the call so that we can repeat it if necessary
		 * through the channel, whilst disposing of the actual call record.
		 */
		trace_rxrpc_disconnect_call(call);
		switch (call->completion) {
		case RXRPC_CALL_SUCCEEDED:
			chan->last_seq = call->rx_highest_seq;
			chan->last_type = RXRPC_PACKET_TYPE_ACK;
			break;
		case RXRPC_CALL_LOCALLY_ABORTED:
			chan->last_abort = call->abort_code;
			chan->last_type = RXRPC_PACKET_TYPE_ABORT;
			break;
		default:
			chan->last_abort = RX_CALL_DEAD;
			chan->last_type = RXRPC_PACKET_TYPE_ABORT;
			break;
		}

		chan->last_call = chan->call_id;
		chan->call_id = chan->call_counter;
		chan->call = NULL;
	}

	_leave("");
}

/*
 * Disconnect a call and clear any channel it occupies when that call
 * terminates.
 */
void rxrpc_disconnect_call(struct rxrpc_call *call)
{
	struct rxrpc_connection *conn = call->conn;

	set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
	rxrpc_see_call(call, rxrpc_call_see_disconnected);

	call->peer->cong_ssthresh = call->cong_ssthresh;

	if (!hlist_unhashed(&call->error_link)) {
		spin_lock(&call->peer->lock);
		hlist_del_init(&call->error_link);
		spin_unlock(&call->peer->lock);
	}

	if (rxrpc_is_client_call(call)) {
		rxrpc_disconnect_client_call(call->bundle, call);
	} else {
		__rxrpc_disconnect_call(conn, call);
		conn->idle_timestamp = jiffies;
		if (atomic_dec_and_test(&conn->active))
			rxrpc_set_service_reap_timer(conn->rxnet,
						     jiffies + rxrpc_connection_expiry * HZ);
	}

	rxrpc_put_call(call, rxrpc_call_put_io_thread);
}

/*
 * Queue a connection's work processor, getting a ref to pass to the work
 * queue.
 */
void rxrpc_queue_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
{
	if (atomic_read(&conn->active) >= 0 &&
	    rxrpc_queue_work(&conn->processor))
		rxrpc_see_connection(conn, why);
}

/*
 * Note the re-emergence of a connection.
 */
void rxrpc_see_connection(struct rxrpc_connection *conn,
			  enum rxrpc_conn_trace why)
{
	if (conn) {
		int r = refcount_read(&conn->ref);

		trace_rxrpc_conn(conn->debug_id, r, why);
	}
}

/*
 * Get a ref on a connection.
 */
struct rxrpc_connection *rxrpc_get_connection(struct rxrpc_connection *conn,
					      enum rxrpc_conn_trace why)
{
	int r;

	__refcount_inc(&conn->ref, &r);
	trace_rxrpc_conn(conn->debug_id, r + 1, why);
	return conn;
}

/*
 * Try to get a ref on a connection.
 */
struct rxrpc_connection *
rxrpc_get_connection_maybe(struct rxrpc_connection *conn,
			   enum rxrpc_conn_trace why)
{
	int r;

	if (conn) {
		if (__refcount_inc_not_zero(&conn->ref, &r))
			trace_rxrpc_conn(conn->debug_id, r + 1, why);
		else
			conn = NULL;
	}
	return conn;
}

/*
 * Set the service connection reap timer.
 */
static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
					 unsigned long reap_at)
{
	if (rxnet->live)
		timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
}

/*
 * destroy a virtual connection
 */
static void rxrpc_rcu_free_connection(struct rcu_head *rcu)
{
	struct rxrpc_connection *conn =
		container_of(rcu, struct rxrpc_connection, rcu);
	struct rxrpc_net *rxnet = conn->rxnet;

	_enter("{%d,u=%d}", conn->debug_id, refcount_read(&conn->ref));

	trace_rxrpc_conn(conn->debug_id, refcount_read(&conn->ref),
			 rxrpc_conn_free);
	kfree(conn);

	if (atomic_dec_and_test(&rxnet->nr_conns))
		wake_up_var(&rxnet->nr_conns);
}

/*
 * Clean up a dead connection.
 */
static void rxrpc_clean_up_connection(struct work_struct *work)
{
	struct rxrpc_connection *conn =
		container_of(work, struct rxrpc_connection, destructor);
	struct rxrpc_net *rxnet = conn->rxnet;

	ASSERT(!conn->channels[0].call &&
	       !conn->channels[1].call &&
	       !conn->channels[2].call &&
	       !conn->channels[3].call);
	ASSERT(list_empty(&conn->cache_link));

	del_timer_sync(&conn->timer);
	cancel_work_sync(&conn->processor); /* Processing may restart the timer */
	del_timer_sync(&conn->timer);

	write_lock(&rxnet->conn_lock);
	list_del_init(&conn->proc_link);
	write_unlock(&rxnet->conn_lock);

	rxrpc_purge_queue(&conn->rx_queue);

	rxrpc_kill_client_conn(conn);

	conn->security->clear(conn);
	key_put(conn->key);
	rxrpc_put_bundle(conn->bundle, rxrpc_bundle_put_conn);
	rxrpc_put_peer(conn->peer, rxrpc_peer_put_conn);
	rxrpc_put_local(conn->local, rxrpc_local_put_kill_conn);

	/* Drain the Rx queue.  Note that even though we've unpublished, an
	 * incoming packet could still be being added to our Rx queue, so we
	 * will need to drain it again in the RCU cleanup handler.
	 */
	rxrpc_purge_queue(&conn->rx_queue);

	if (conn->tx_data_alloc.va)
		__page_frag_cache_drain(virt_to_page(conn->tx_data_alloc.va),
					conn->tx_data_alloc.pagecnt_bias);
	call_rcu(&conn->rcu, rxrpc_rcu_free_connection);
}

/*
 * Drop a ref on a connection.
 */
void rxrpc_put_connection(struct rxrpc_connection *conn,
			  enum rxrpc_conn_trace why)
{
	unsigned int debug_id;
	bool dead;
	int r;

	if (!conn)
		return;

	debug_id = conn->debug_id;
	dead = __refcount_dec_and_test(&conn->ref, &r);
	trace_rxrpc_conn(debug_id, r - 1, why);
	if (dead) {
		del_timer(&conn->timer);
		cancel_work(&conn->processor);

		if (in_softirq() || work_busy(&conn->processor) ||
		    timer_pending(&conn->timer))
			/* Can't use the rxrpc workqueue as we need to cancel/flush
			 * something that may be running/waiting there.
			 */
			schedule_work(&conn->destructor);
		else
			rxrpc_clean_up_connection(&conn->destructor);
	}
}

/*
 * reap dead service connections
 */
void rxrpc_service_connection_reaper(struct work_struct *work)
{
	struct rxrpc_connection *conn, *_p;
	struct rxrpc_net *rxnet =
		container_of(work, struct rxrpc_net, service_conn_reaper);
	unsigned long expire_at, earliest, idle_timestamp, now;
	int active;

	LIST_HEAD(graveyard);

	_enter("");

	now = jiffies;
	earliest = now + MAX_JIFFY_OFFSET;

	write_lock(&rxnet->conn_lock);
	list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
		ASSERTCMP(atomic_read(&conn->active), >=, 0);
		if (likely(atomic_read(&conn->active) > 0))
			continue;
		if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
			continue;

		if (rxnet->live && !conn->local->dead) {
			idle_timestamp = READ_ONCE(conn->idle_timestamp);
			expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
			if (conn->local->service_closed)
				expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;

			_debug("reap CONN %d { a=%d,t=%ld }",
			       conn->debug_id, atomic_read(&conn->active),
			       (long)expire_at - (long)now);

			if (time_before(now, expire_at)) {
				if (time_before(expire_at, earliest))
					earliest = expire_at;
				continue;
			}
		}

		/* The activity count sits at 0 whilst the conn is unused on
		 * the list; we reduce that to -1 to make the conn unavailable.
		 */
		active = 0;
		if (!atomic_try_cmpxchg(&conn->active, &active, -1))
			continue;
		rxrpc_see_connection(conn, rxrpc_conn_see_reap_service);

		if (rxrpc_conn_is_client(conn))
			BUG();
		else
			rxrpc_unpublish_service_conn(conn);

		list_move_tail(&conn->link, &graveyard);
	}
	write_unlock(&rxnet->conn_lock);

	if (earliest != now + MAX_JIFFY_OFFSET) {
		_debug("reschedule reaper %ld", (long)earliest - (long)now);
		ASSERT(time_after(earliest, now));
		rxrpc_set_service_reap_timer(rxnet, earliest);
	}

	while (!list_empty(&graveyard)) {
		conn = list_entry(graveyard.next, struct rxrpc_connection,
				  link);
		list_del_init(&conn->link);

		ASSERTCMP(atomic_read(&conn->active), ==, -1);
		rxrpc_put_connection(conn, rxrpc_conn_put_service_reaped);
	}

	_leave("");
}

/*
 * preemptively destroy all the service connection records rather than
 * waiting for them to time out
 */
void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
{
	struct rxrpc_connection *conn, *_p;
	bool leak = false;

	_enter("");

	atomic_dec(&rxnet->nr_conns);

	del_timer_sync(&rxnet->service_conn_reap_timer);
	rxrpc_queue_work(&rxnet->service_conn_reaper);
	flush_workqueue(rxrpc_workqueue);

	write_lock(&rxnet->conn_lock);
	list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
		pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
		       conn, refcount_read(&conn->ref));
		leak = true;
	}
	write_unlock(&rxnet->conn_lock);
	BUG_ON(leak);

	ASSERT(list_empty(&rxnet->conn_proc_list));

	/* We need to wait for the connections to be destroyed by RCU as they
	 * pin things that we still need to get rid of.
	 */
	wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
	_leave("");
}