[net-next-2.6.git] / net / rxrpc / ar-transport.c

/* RxRPC point-to-point transport session management
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

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

static void rxrpc_transport_reaper(struct work_struct *work);

static LIST_HEAD(rxrpc_transports);
static DEFINE_RWLOCK(rxrpc_transport_lock);
static unsigned long rxrpc_transport_timeout = 3600 * 24;
static DECLARE_DELAYED_WORK(rxrpc_transport_reap, rxrpc_transport_reaper);

/*
 * allocate a new transport session manager
 */
static struct rxrpc_transport *rxrpc_alloc_transport(struct rxrpc_local *local,
						     struct rxrpc_peer *peer,
						     gfp_t gfp)
{
	struct rxrpc_transport *trans;

	_enter("");

	trans = kzalloc(sizeof(struct rxrpc_transport), gfp);
	if (trans) {
		trans->local = local;
		trans->peer = peer;
		INIT_LIST_HEAD(&trans->link);
		trans->bundles = RB_ROOT;
		trans->client_conns = RB_ROOT;
		trans->server_conns = RB_ROOT;
		skb_queue_head_init(&trans->error_queue);
		spin_lock_init(&trans->client_lock);
		rwlock_init(&trans->conn_lock);
		atomic_set(&trans->usage, 1);
		trans->debug_id = atomic_inc_return(&rxrpc_debug_id);

		if (peer->srx.transport.family == AF_INET) {
			switch (peer->srx.transport_type) {
			case SOCK_DGRAM:
				INIT_WORK(&trans->error_handler,
					  rxrpc_UDP_error_handler);
				break;
			default:
				BUG();
				break;
			}
		} else {
			BUG();
		}
	}

	_leave(" = %p", trans);
	return trans;
}

/*
 * obtain a transport session for the nominated endpoints
 */
struct rxrpc_transport *rxrpc_get_transport(struct rxrpc_local *local,
					    struct rxrpc_peer *peer,
					    gfp_t gfp)
{
	struct rxrpc_transport *trans, *candidate;
	const char *new = "old";
	int usage;

	_enter("{%pI4+%hu},{%pI4+%hu},",
	       &local->srx.transport.sin.sin_addr,
	       ntohs(local->srx.transport.sin.sin_port),
	       &peer->srx.transport.sin.sin_addr,
	       ntohs(peer->srx.transport.sin.sin_port));

	/* search the transport list first */
	read_lock_bh(&rxrpc_transport_lock);
	list_for_each_entry(trans, &rxrpc_transports, link) {
		if (trans->local == local && trans->peer == peer)
			goto found_extant_transport;
	}
	read_unlock_bh(&rxrpc_transport_lock);

	/* not yet present - create a candidate for a new record and then
	 * redo the search */
	candidate = rxrpc_alloc_transport(local, peer, gfp);
	if (!candidate) {
		_leave(" = -ENOMEM");
		return ERR_PTR(-ENOMEM);
	}

	write_lock_bh(&rxrpc_transport_lock);

	list_for_each_entry(trans, &rxrpc_transports, link) {
		if (trans->local == local && trans->peer == peer)
			goto found_extant_second;
	}

	/* we can now add the new candidate to the list */
	trans = candidate;
	candidate = NULL;

	rxrpc_get_local(trans->local);
	atomic_inc(&trans->peer->usage);
	list_add_tail(&trans->link, &rxrpc_transports);
	write_unlock_bh(&rxrpc_transport_lock);
	new = "new";

success:
	_net("TRANSPORT %s %d local %d -> peer %d",
	     new,
	     trans->debug_id,
	     trans->local->debug_id,
	     trans->peer->debug_id);

	_leave(" = %p {u=%d}", trans, atomic_read(&trans->usage));
	return trans;

	/* we found the transport in the list immediately */
found_extant_transport:
	usage = atomic_inc_return(&trans->usage);
	read_unlock_bh(&rxrpc_transport_lock);
	goto success;

	/* we found the transport on the second time through the list */
found_extant_second:
	usage = atomic_inc_return(&trans->usage);
	write_unlock_bh(&rxrpc_transport_lock);
	kfree(candidate);
	goto success;
}

/*
 * find the transport connecting two endpoints
 */
struct rxrpc_transport *rxrpc_find_transport(struct rxrpc_local *local,
					     struct rxrpc_peer *peer)
{
	struct rxrpc_transport *trans;

	_enter("{%pI4+%hu},{%pI4+%hu},",
	       &local->srx.transport.sin.sin_addr,
	       ntohs(local->srx.transport.sin.sin_port),
	       &peer->srx.transport.sin.sin_addr,
	       ntohs(peer->srx.transport.sin.sin_port));

	/* search the transport list */
	read_lock_bh(&rxrpc_transport_lock);

	list_for_each_entry(trans, &rxrpc_transports, link) {
		if (trans->local == local && trans->peer == peer)
			goto found_extant_transport;
	}

	read_unlock_bh(&rxrpc_transport_lock);
	_leave(" = NULL");
	return NULL;

found_extant_transport:
	atomic_inc(&trans->usage);
	read_unlock_bh(&rxrpc_transport_lock);
	_leave(" = %p", trans);
	return trans;
}

/*
 * release a transport session
 */
void rxrpc_put_transport(struct rxrpc_transport *trans)
{
	_enter("%p{u=%d}", trans, atomic_read(&trans->usage));

	ASSERTCMP(atomic_read(&trans->usage), >, 0);

	trans->put_time = get_seconds();
	if (unlikely(atomic_dec_and_test(&trans->usage))) {
		_debug("zombie");
		/* let the reaper determine the timeout to avoid a race with
		 * overextending the timeout if the reaper is running at the
		 * same time */
		rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);
	}
	_leave("");
}

/*
 * clean up a transport session
 */
static void rxrpc_cleanup_transport(struct rxrpc_transport *trans)
{
	_net("DESTROY TRANS %d", trans->debug_id);

	rxrpc_purge_queue(&trans->error_queue);

	rxrpc_put_local(trans->local);
	rxrpc_put_peer(trans->peer);
	kfree(trans);
}

/*
 * reap dead transports that have passed their expiry date
 */
static void rxrpc_transport_reaper(struct work_struct *work)
{
	struct rxrpc_transport *trans, *_p;
	unsigned long now, earliest, reap_time;

	LIST_HEAD(graveyard);

	_enter("");

	now = get_seconds();
	earliest = ULONG_MAX;

	/* extract all the transports that have been dead too long */
	write_lock_bh(&rxrpc_transport_lock);
	list_for_each_entry_safe(trans, _p, &rxrpc_transports, link) {
		_debug("reap TRANS %d { u=%d t=%ld }",
		       trans->debug_id, atomic_read(&trans->usage),
		       (long) now - (long) trans->put_time);

		if (likely(atomic_read(&trans->usage) > 0))
			continue;

		reap_time = trans->put_time + rxrpc_transport_timeout;
		if (reap_time <= now)
			list_move_tail(&trans->link, &graveyard);
		else if (reap_time < earliest)
			earliest = reap_time;
	}
	write_unlock_bh(&rxrpc_transport_lock);

	if (earliest != ULONG_MAX) {
		_debug("reschedule reaper %ld", (long) earliest - now);
		ASSERTCMP(earliest, >, now);
		rxrpc_queue_delayed_work(&rxrpc_transport_reap,
					 (earliest - now) * HZ);
	}

	/* then destroy all those pulled out */
	while (!list_empty(&graveyard)) {
		trans = list_entry(graveyard.next, struct rxrpc_transport,
				   link);
		list_del_init(&trans->link);

		ASSERTCMP(atomic_read(&trans->usage), ==, 0);
		rxrpc_cleanup_transport(trans);
	}

	_leave("");
}

/*
 * preemptively destroy all the transport session records rather than waiting
 * for them to time out
 */
void __exit rxrpc_destroy_all_transports(void)
{
	_enter("");

	rxrpc_transport_timeout = 0;
	cancel_delayed_work(&rxrpc_transport_reap);
	rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);

	_leave("");
}
Commit	Line	Data
17926a79 DH	1	/* RxRPC point-to-point transport session management
	2	*
	3	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/net.h>
	14	#include <linux/skbuff.h>
5a0e3ad6	15	#include <linux/slab.h>
17926a79 DH	16	#include <net/sock.h>
	17	#include <net/af_rxrpc.h>
	18	#include "ar-internal.h"
	19
	20	static void rxrpc_transport_reaper(struct work_struct *work);
	21
	22	static LIST_HEAD(rxrpc_transports);
	23	static DEFINE_RWLOCK(rxrpc_transport_lock);
	24	static unsigned long rxrpc_transport_timeout = 3600 * 24;
	25	static DECLARE_DELAYED_WORK(rxrpc_transport_reap, rxrpc_transport_reaper);
	26
	27	/*
	28	* allocate a new transport session manager
	29	*/
	30	static struct rxrpc_transport rxrpc_alloc_transport(struct rxrpc_local local,
	31	struct rxrpc_peer *peer,
	32	gfp_t gfp)
	33	{
	34	struct rxrpc_transport *trans;
	35
	36	_enter("");
	37
	38	trans = kzalloc(sizeof(struct rxrpc_transport), gfp);
	39	if (trans) {
	40	trans->local = local;
	41	trans->peer = peer;
	42	INIT_LIST_HEAD(&trans->link);
	43	trans->bundles = RB_ROOT;
	44	trans->client_conns = RB_ROOT;
	45	trans->server_conns = RB_ROOT;
	46	skb_queue_head_init(&trans->error_queue);
	47	spin_lock_init(&trans->client_lock);
	48	rwlock_init(&trans->conn_lock);
	49	atomic_set(&trans->usage, 1);
	50	trans->debug_id = atomic_inc_return(&rxrpc_debug_id);
	51
	52	if (peer->srx.transport.family == AF_INET) {
	53	switch (peer->srx.transport_type) {
	54	case SOCK_DGRAM:
	55	INIT_WORK(&trans->error_handler,
	56	rxrpc_UDP_error_handler);
	57	break;
	58	default:
	59	BUG();
	60	break;
	61	}
	62	} else {
	63	BUG();
	64	}
	65	}
	66
	67	_leave(" = %p", trans);
	68	return trans;
	69	}
	70
	71	/*
	72	* obtain a transport session for the nominated endpoints
	73	*/
	74	struct rxrpc_transport rxrpc_get_transport(struct rxrpc_local local,
	75	struct rxrpc_peer *peer,
	76	gfp_t gfp)
	77	{
	78	struct rxrpc_transport trans, candidate;
	79	const char *new = "old";
80	int usage;
81
21454aaa HH	82	_enter("{%pI4+%hu},{%pI4+%hu},",
21454aaa HH	83	&local->srx.transport.sin.sin_addr,
17926a79	84	ntohs(local->srx.transport.sin.sin_port),
21454aaa	85	&peer->srx.transport.sin.sin_addr,
17926a79 DH	86	ntohs(peer->srx.transport.sin.sin_port));
	87
	88	/* search the transport list first */
	89	read_lock_bh(&rxrpc_transport_lock);
	90	list_for_each_entry(trans, &rxrpc_transports, link) {
	91	if (trans->local == local && trans->peer == peer)
	92	goto found_extant_transport;
	93	}
	94	read_unlock_bh(&rxrpc_transport_lock);
	95
	96	/* not yet present - create a candidate for a new record and then
	97	* redo the search */
	98	candidate = rxrpc_alloc_transport(local, peer, gfp);
	99	if (!candidate) {
	100	_leave(" = -ENOMEM");
	101	return ERR_PTR(-ENOMEM);
	102	}
	103
	104	write_lock_bh(&rxrpc_transport_lock);
	105
	106	list_for_each_entry(trans, &rxrpc_transports, link) {
	107	if (trans->local == local && trans->peer == peer)
	108	goto found_extant_second;
	109	}
	110
	111	/* we can now add the new candidate to the list */
	112	trans = candidate;
	113	candidate = NULL;
	114
	115	rxrpc_get_local(trans->local);
	116	atomic_inc(&trans->peer->usage);
	117	list_add_tail(&trans->link, &rxrpc_transports);
	118	write_unlock_bh(&rxrpc_transport_lock);
	119	new = "new";
	120
	121	success:
	122	_net("TRANSPORT %s %d local %d -> peer %d",
	123	new,
	124	trans->debug_id,
	125	trans->local->debug_id,
	126	trans->peer->debug_id);
	127
	128	_leave(" = %p {u=%d}", trans, atomic_read(&trans->usage));
	129	return trans;
	130
	131	/* we found the transport in the list immediately */
	132	found_extant_transport:
	133	usage = atomic_inc_return(&trans->usage);
	134	read_unlock_bh(&rxrpc_transport_lock);
	135	goto success;
	136
	137	/* we found the transport on the second time through the list */
	138	found_extant_second:
	139	usage = atomic_inc_return(&trans->usage);
	140	write_unlock_bh(&rxrpc_transport_lock);
	141	kfree(candidate);
	142	goto success;
	143	}
	144
	145	/*
	146	* find the transport connecting two endpoints
	147	*/
	148	struct rxrpc_transport rxrpc_find_transport(struct rxrpc_local local,
	149	struct rxrpc_peer *peer)
150	{
151	struct rxrpc_transport *trans;
152
21454aaa HH	153	_enter("{%pI4+%hu},{%pI4+%hu},",
21454aaa HH	154	&local->srx.transport.sin.sin_addr,
17926a79	155	ntohs(local->srx.transport.sin.sin_port),
21454aaa	156	&peer->srx.transport.sin.sin_addr,
17926a79 DH	157	ntohs(peer->srx.transport.sin.sin_port));
	158
	159	/* search the transport list */
	160	read_lock_bh(&rxrpc_transport_lock);
	161
	162	list_for_each_entry(trans, &rxrpc_transports, link) {
	163	if (trans->local == local && trans->peer == peer)
	164	goto found_extant_transport;
	165	}
	166
	167	read_unlock_bh(&rxrpc_transport_lock);
	168	_leave(" = NULL");
	169	return NULL;
	170
	171	found_extant_transport:
	172	atomic_inc(&trans->usage);
	173	read_unlock_bh(&rxrpc_transport_lock);
	174	_leave(" = %p", trans);
	175	return trans;
	176	}
	177
	178	/*
	179	* release a transport session
	180	*/
	181	void rxrpc_put_transport(struct rxrpc_transport *trans)
	182	{
	183	_enter("%p{u=%d}", trans, atomic_read(&trans->usage));
	184
	185	ASSERTCMP(atomic_read(&trans->usage), >, 0);
	186
2c6b47de	187	trans->put_time = get_seconds();
50aab54f	188	if (unlikely(atomic_dec_and_test(&trans->usage))) {
17926a79 DH	189	_debug("zombie");
	190	/* let the reaper determine the timeout to avoid a race with
	191	* overextending the timeout if the reaper is running at the
	192	* same time */
651350d1	193	rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);
50aab54f	194	}
17926a79 DH	195	_leave("");
	196	}
	197
	198	/*
	199	* clean up a transport session
	200	*/
	201	static void rxrpc_cleanup_transport(struct rxrpc_transport *trans)
	202	{
	203	_net("DESTROY TRANS %d", trans->debug_id);
	204
	205	rxrpc_purge_queue(&trans->error_queue);
	206
	207	rxrpc_put_local(trans->local);
	208	rxrpc_put_peer(trans->peer);
	209	kfree(trans);
	210	}
	211
	212	/*
	213	* reap dead transports that have passed their expiry date
	214	*/
	215	static void rxrpc_transport_reaper(struct work_struct *work)
	216	{
	217	struct rxrpc_transport trans, _p;
	218	unsigned long now, earliest, reap_time;
	219
	220	LIST_HEAD(graveyard);
	221
	222	_enter("");
	223
2c6b47de	224	now = get_seconds();
17926a79 DH	225	earliest = ULONG_MAX;
	226
	227	/* extract all the transports that have been dead too long */
	228	write_lock_bh(&rxrpc_transport_lock);
	229	list_for_each_entry_safe(trans, _p, &rxrpc_transports, link) {
	230	_debug("reap TRANS %d { u=%d t=%ld }",
	231	trans->debug_id, atomic_read(&trans->usage),
	232	(long) now - (long) trans->put_time);
	233
	234	if (likely(atomic_read(&trans->usage) > 0))
	235	continue;
	236
	237	reap_time = trans->put_time + rxrpc_transport_timeout;
	238	if (reap_time <= now)
	239	list_move_tail(&trans->link, &graveyard);
	240	else if (reap_time < earliest)
	241	earliest = reap_time;
	242	}
	243	write_unlock_bh(&rxrpc_transport_lock);
	244
	245	if (earliest != ULONG_MAX) {
	246	_debug("reschedule reaper %ld", (long) earliest - now);
	247	ASSERTCMP(earliest, >, now);
651350d1 DH	248	rxrpc_queue_delayed_work(&rxrpc_transport_reap,
651350d1 DH	249	(earliest - now) * HZ);
17926a79 DH	250	}
	251
	252	/* then destroy all those pulled out */
	253	while (!list_empty(&graveyard)) {
	254	trans = list_entry(graveyard.next, struct rxrpc_transport,
	255	link);
	256	list_del_init(&trans->link);
	257
	258	ASSERTCMP(atomic_read(&trans->usage), ==, 0);
	259	rxrpc_cleanup_transport(trans);
	260	}
	261
	262	_leave("");
	263	}
	264
	265	/*
	266	* preemptively destroy all the transport session records rather than waiting
	267	* for them to time out
	268	*/
	269	void __exit rxrpc_destroy_all_transports(void)
	270	{
	271	_enter("");
	272
	273	rxrpc_transport_timeout = 0;
	274	cancel_delayed_work(&rxrpc_transport_reap);
651350d1	275	rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);
17926a79 DH	276
	277	_leave("");
	278	}