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 */
 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_irq(&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_irq(&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		INIT_LIST_HEAD(&conn->attend_link);
 71		mutex_init(&conn->security_lock);
 72		mutex_init(&conn->tx_data_alloc_lock);
 73		skb_queue_head_init(&conn->rx_queue);
 74		conn->rxnet = rxnet;
 75		conn->security = &rxrpc_no_security;
 76		rwlock_init(&conn->security_use_lock);
 77		spin_lock_init(&conn->state_lock);
 78		conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
 79		conn->idle_timestamp = jiffies;
 80	}
 81
 82	_leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
 83	return conn;
 84}
 85
 86/*
 87 * Look up a connection in the cache by protocol parameters.
 88 *
 89 * If successful, a pointer to the connection is returned, but no ref is taken.
 90 * NULL is returned if there is no match.
 91 *
 92 * When searching for a service call, if we find a peer but no connection, we
 93 * return that through *_peer in case we need to create a new service call.
 94 *
 95 * The caller must be holding the RCU read lock.
 96 */
 97struct rxrpc_connection *rxrpc_find_client_connection_rcu(struct rxrpc_local *local,
 98							  struct sockaddr_rxrpc *srx,
 99							  struct sk_buff *skb)
100{
101	struct rxrpc_connection *conn;
102	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
103	struct rxrpc_peer *peer;
104
105	_enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
106
107	/* Look up client connections by connection ID alone as their
108	 * IDs are unique for this machine.
109	 */
110	conn = idr_find(&local->conn_ids, sp->hdr.cid >> RXRPC_CIDSHIFT);
111	if (!conn || refcount_read(&conn->ref) == 0) {
112		_debug("no conn");
113		goto not_found;
114	}
115
116	if (conn->proto.epoch != sp->hdr.epoch ||
117	    conn->local != local)
118		goto not_found;
119
120	peer = conn->peer;
121	switch (srx->transport.family) {
122	case AF_INET:
123		if (peer->srx.transport.sin.sin_port !=
124		    srx->transport.sin.sin_port)
125			goto not_found;
126		break;
127#ifdef CONFIG_AF_RXRPC_IPV6
128	case AF_INET6:
129		if (peer->srx.transport.sin6.sin6_port !=
130		    srx->transport.sin6.sin6_port)
131			goto not_found;
132		break;
133#endif
134	default:
135		BUG();
136	}
137
138	_leave(" = %p", conn);
139	return conn;
140
141not_found:
142	_leave(" = NULL");
143	return NULL;
144}
145
146/*
147 * Disconnect a call and clear any channel it occupies when that call
148 * terminates.  The caller must hold the channel_lock and must release the
149 * call's ref on the connection.
150 */
151void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
152			     struct rxrpc_call *call)
153{
154	struct rxrpc_channel *chan =
155		&conn->channels[call->cid & RXRPC_CHANNELMASK];
156
157	_enter("%d,%x", conn->debug_id, call->cid);
158
159	if (chan->call == call) {
160		/* Save the result of the call so that we can repeat it if necessary
161		 * through the channel, whilst disposing of the actual call record.
162		 */
163		trace_rxrpc_disconnect_call(call);
164		switch (call->completion) {
165		case RXRPC_CALL_SUCCEEDED:
166			chan->last_seq = call->rx_highest_seq;
167			chan->last_type = RXRPC_PACKET_TYPE_ACK;
168			break;
169		case RXRPC_CALL_LOCALLY_ABORTED:
170			chan->last_abort = call->abort_code;
171			chan->last_type = RXRPC_PACKET_TYPE_ABORT;
172			break;
173		default:
174			chan->last_abort = RX_CALL_DEAD;
175			chan->last_type = RXRPC_PACKET_TYPE_ABORT;
176			break;
177		}
178
179		chan->last_call = chan->call_id;
180		chan->call_id = chan->call_counter;
181		chan->call = NULL;
182	}
183
184	_leave("");
185}
186
187/*
188 * Disconnect a call and clear any channel it occupies when that call
189 * terminates.
190 */
191void rxrpc_disconnect_call(struct rxrpc_call *call)
192{
193	struct rxrpc_connection *conn = call->conn;
194
195	set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
196	rxrpc_see_call(call, rxrpc_call_see_disconnected);
197
198	call->peer->cong_ssthresh = call->cong_ssthresh;
199
200	if (!hlist_unhashed(&call->error_link)) {
201		spin_lock_irq(&call->peer->lock);
202		hlist_del_init(&call->error_link);
203		spin_unlock_irq(&call->peer->lock);
204	}
205
206	if (rxrpc_is_client_call(call)) {
207		rxrpc_disconnect_client_call(call->bundle, call);
208	} else {
209		__rxrpc_disconnect_call(conn, call);
210		conn->idle_timestamp = jiffies;
211		if (atomic_dec_and_test(&conn->active))
212			rxrpc_set_service_reap_timer(conn->rxnet,
213						     jiffies + rxrpc_connection_expiry * HZ);
214	}
215
216	rxrpc_put_call(call, rxrpc_call_put_io_thread);
217}
218
219/*
220 * Queue a connection's work processor, getting a ref to pass to the work
221 * queue.
222 */
223void rxrpc_queue_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
224{
225	if (atomic_read(&conn->active) >= 0 &&
226	    rxrpc_queue_work(&conn->processor))
227		rxrpc_see_connection(conn, why);
228}
229
230/*
231 * Note the re-emergence of a connection.
232 */
233void rxrpc_see_connection(struct rxrpc_connection *conn,
234			  enum rxrpc_conn_trace why)
235{
236	if (conn) {
237		int r = refcount_read(&conn->ref);
238
239		trace_rxrpc_conn(conn->debug_id, r, why);
240	}
241}
242
243/*
244 * Get a ref on a connection.
245 */
246struct rxrpc_connection *rxrpc_get_connection(struct rxrpc_connection *conn,
247					      enum rxrpc_conn_trace why)
248{
249	int r;
250
251	__refcount_inc(&conn->ref, &r);
252	trace_rxrpc_conn(conn->debug_id, r + 1, why);
253	return conn;
254}
255
256/*
257 * Try to get a ref on a connection.
258 */
259struct rxrpc_connection *
260rxrpc_get_connection_maybe(struct rxrpc_connection *conn,
261			   enum rxrpc_conn_trace why)
262{
263	int r;
264
265	if (conn) {
266		if (__refcount_inc_not_zero(&conn->ref, &r))
267			trace_rxrpc_conn(conn->debug_id, r + 1, why);
268		else
269			conn = NULL;
270	}
271	return conn;
272}
273
274/*
275 * Set the service connection reap timer.
276 */
277static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
278					 unsigned long reap_at)
279{
280	if (rxnet->live)
281		timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
282}
283
284/*
285 * destroy a virtual connection
286 */
287static void rxrpc_rcu_free_connection(struct rcu_head *rcu)
288{
289	struct rxrpc_connection *conn =
290		container_of(rcu, struct rxrpc_connection, rcu);
291	struct rxrpc_net *rxnet = conn->rxnet;
292
293	_enter("{%d,u=%d}", conn->debug_id, refcount_read(&conn->ref));
294
295	trace_rxrpc_conn(conn->debug_id, refcount_read(&conn->ref),
296			 rxrpc_conn_free);
297	kfree(conn);
298
299	if (atomic_dec_and_test(&rxnet->nr_conns))
300		wake_up_var(&rxnet->nr_conns);
301}
302
303/*
304 * Clean up a dead connection.
305 */
306static void rxrpc_clean_up_connection(struct work_struct *work)
307{
308	struct rxrpc_connection *conn =
309		container_of(work, struct rxrpc_connection, destructor);
310	struct rxrpc_net *rxnet = conn->rxnet;
311
312	ASSERT(!conn->channels[0].call &&
313	       !conn->channels[1].call &&
314	       !conn->channels[2].call &&
315	       !conn->channels[3].call);
316	ASSERT(list_empty(&conn->cache_link));
317
318	timer_delete_sync(&conn->timer);
319	cancel_work_sync(&conn->processor); /* Processing may restart the timer */
320	timer_delete_sync(&conn->timer);
321
322	write_lock(&rxnet->conn_lock);
323	list_del_init(&conn->proc_link);
324	write_unlock(&rxnet->conn_lock);
325
326	if (conn->pmtud_probe) {
327		trace_rxrpc_pmtud_lost(conn, 0);
328		conn->peer->pmtud_probing = false;
329		conn->peer->pmtud_pending = true;
330	}
331
332	rxrpc_purge_queue(&conn->rx_queue);
333	rxrpc_free_skb(conn->tx_response, rxrpc_skb_put_response);
334
335	rxrpc_kill_client_conn(conn);
336
337	conn->security->clear(conn);
338	key_put(conn->key);
339	rxrpc_put_bundle(conn->bundle, rxrpc_bundle_put_conn);
340	rxrpc_put_peer(conn->peer, rxrpc_peer_put_conn);
341	rxrpc_put_local(conn->local, rxrpc_local_put_kill_conn);
342
343	/* Drain the Rx queue.  Note that even though we've unpublished, an
344	 * incoming packet could still be being added to our Rx queue, so we
345	 * will need to drain it again in the RCU cleanup handler.
346	 */
347	rxrpc_purge_queue(&conn->rx_queue);
348
349	page_frag_cache_drain(&conn->tx_data_alloc);
350	call_rcu(&conn->rcu, rxrpc_rcu_free_connection);
351}
352
353/*
354 * Drop a ref on a connection.
355 */
356void rxrpc_put_connection(struct rxrpc_connection *conn,
357			  enum rxrpc_conn_trace why)
358{
359	unsigned int debug_id;
360	bool dead;
361	int r;
362
363	if (!conn)
364		return;
365
366	debug_id = conn->debug_id;
367	dead = __refcount_dec_and_test(&conn->ref, &r);
368	trace_rxrpc_conn(debug_id, r - 1, why);
369	if (dead) {
370		timer_delete(&conn->timer);
371		cancel_work(&conn->processor);
372
373		if (in_softirq() || work_busy(&conn->processor) ||
374		    timer_pending(&conn->timer))
375			/* Can't use the rxrpc workqueue as we need to cancel/flush
376			 * something that may be running/waiting there.
377			 */
378			schedule_work(&conn->destructor);
379		else
380			rxrpc_clean_up_connection(&conn->destructor);
381	}
382}
383
384/*
385 * reap dead service connections
386 */
387void rxrpc_service_connection_reaper(struct work_struct *work)
388{
389	struct rxrpc_connection *conn, *_p;
390	struct rxrpc_net *rxnet =
391		container_of(work, struct rxrpc_net, service_conn_reaper);
392	unsigned long expire_at, earliest, idle_timestamp, now;
393	int active;
394
395	LIST_HEAD(graveyard);
396
397	_enter("");
398
399	now = jiffies;
400	earliest = now + MAX_JIFFY_OFFSET;
401
402	write_lock(&rxnet->conn_lock);
403	list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
404		ASSERTCMP(atomic_read(&conn->active), >=, 0);
405		if (likely(atomic_read(&conn->active) > 0))
406			continue;
407		if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
408			continue;
409
410		if (rxnet->live && !conn->local->dead) {
411			idle_timestamp = READ_ONCE(conn->idle_timestamp);
412			expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
413			if (conn->local->service_closed)
414				expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
415
416			_debug("reap CONN %d { a=%d,t=%ld }",
417			       conn->debug_id, atomic_read(&conn->active),
418			       (long)expire_at - (long)now);
419
420			if (time_before(now, expire_at)) {
421				if (time_before(expire_at, earliest))
422					earliest = expire_at;
423				continue;
424			}
425		}
426
427		/* The activity count sits at 0 whilst the conn is unused on
428		 * the list; we reduce that to -1 to make the conn unavailable.
429		 */
430		active = 0;
431		if (!atomic_try_cmpxchg(&conn->active, &active, -1))
432			continue;
433		rxrpc_see_connection(conn, rxrpc_conn_see_reap_service);
434
435		if (rxrpc_conn_is_client(conn))
436			BUG();
437		else
438			rxrpc_unpublish_service_conn(conn);
439
440		list_move_tail(&conn->link, &graveyard);
441	}
442	write_unlock(&rxnet->conn_lock);
443
444	if (earliest != now + MAX_JIFFY_OFFSET) {
445		_debug("reschedule reaper %ld", (long)earliest - (long)now);
446		ASSERT(time_after(earliest, now));
447		rxrpc_set_service_reap_timer(rxnet, earliest);
448	}
449
450	while (!list_empty(&graveyard)) {
451		conn = list_entry(graveyard.next, struct rxrpc_connection,
452				  link);
453		list_del_init(&conn->link);
454
455		ASSERTCMP(atomic_read(&conn->active), ==, -1);
456		rxrpc_put_connection(conn, rxrpc_conn_put_service_reaped);
457	}
458
459	_leave("");
460}
461
462/*
463 * preemptively destroy all the service connection records rather than
464 * waiting for them to time out
465 */
466void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
467{
468	struct rxrpc_connection *conn, *_p;
469	bool leak = false;
470
471	_enter("");
472
473	atomic_dec(&rxnet->nr_conns);
474
475	timer_delete_sync(&rxnet->service_conn_reap_timer);
476	rxrpc_queue_work(&rxnet->service_conn_reaper);
477	flush_workqueue(rxrpc_workqueue);
478
479	write_lock(&rxnet->conn_lock);
480	list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
481		pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
482		       conn, refcount_read(&conn->ref));
483		leak = true;
484	}
485	write_unlock(&rxnet->conn_lock);
486	BUG_ON(leak);
487
488	ASSERT(list_empty(&rxnet->conn_proc_list));
489
490	/* We need to wait for the connections to be destroyed by RCU as they
491	 * pin things that we still need to get rid of.
492	 */
493	wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
494	_leave("");
495}