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 */
19unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
20unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
21
22static void rxrpc_clean_up_connection(struct work_struct *work);
23static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
24					 unsigned long reap_at);
25
26void 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
44static 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 */
55struct 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 */
95struct 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
139not_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 */
149void __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 */
189void 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 */
221void 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 */
231void 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 */
244struct 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 */
257struct rxrpc_connection *
258rxrpc_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 */
275static 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 */
285static 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 */
304static 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 */
349void 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 */
380void 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 */
459void 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