[linux.git] / net / rxrpc / ar-local.c

/* AF_RXRPC local endpoint management
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * 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 LIST_HEAD(rxrpc_locals);
DEFINE_RWLOCK(rxrpc_local_lock);
static DECLARE_RWSEM(rxrpc_local_sem);
static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq);

static void rxrpc_destroy_local(struct work_struct *work);

/*
 * allocate a new local
 */
static
struct rxrpc_local *rxrpc_alloc_local(struct sockaddr_rxrpc *srx)
{
	struct rxrpc_local *local;

	local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
	if (local) {
		INIT_WORK(&local->destroyer, &rxrpc_destroy_local);
		INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls);
		INIT_WORK(&local->rejecter, &rxrpc_reject_packets);
		INIT_LIST_HEAD(&local->services);
		INIT_LIST_HEAD(&local->link);
		init_rwsem(&local->defrag_sem);
		skb_queue_head_init(&local->accept_queue);
		skb_queue_head_init(&local->reject_queue);
		spin_lock_init(&local->lock);
		rwlock_init(&local->services_lock);
		atomic_set(&local->usage, 1);
		local->debug_id = atomic_inc_return(&rxrpc_debug_id);
		memcpy(&local->srx, srx, sizeof(*srx));
	}

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

/*
 * create the local socket
 * - must be called with rxrpc_local_sem writelocked
 */
static int rxrpc_create_local(struct rxrpc_local *local)
{
	struct sock *sock;
	int ret, opt;

	_enter("%p{%d}", local, local->srx.transport_type);

	/* create a socket to represent the local endpoint */
	ret = sock_create_kern(PF_INET, local->srx.transport_type, IPPROTO_UDP,
			       &local->socket);
	if (ret < 0) {
		_leave(" = %d [socket]", ret);
		return ret;
	}

	/* if a local address was supplied then bind it */
	if (local->srx.transport_len > sizeof(sa_family_t)) {
		_debug("bind");
		ret = kernel_bind(local->socket,
				  (struct sockaddr *) &local->srx.transport,
				  local->srx.transport_len);
		if (ret < 0) {
			_debug("bind failed");
			goto error;
		}
	}

	/* we want to receive ICMP errors */
	opt = 1;
	ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
				(char *) &opt, sizeof(opt));
	if (ret < 0) {
		_debug("setsockopt failed");
		goto error;
	}

	/* we want to set the don't fragment bit */
	opt = IP_PMTUDISC_DO;
	ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
				(char *) &opt, sizeof(opt));
	if (ret < 0) {
		_debug("setsockopt failed");
		goto error;
	}

	write_lock_bh(&rxrpc_local_lock);
	list_add(&local->link, &rxrpc_locals);
	write_unlock_bh(&rxrpc_local_lock);

	/* set the socket up */
	sock = local->socket->sk;
	sock->sk_user_data	= local;
	sock->sk_data_ready	= rxrpc_data_ready;
	sock->sk_error_report	= rxrpc_UDP_error_report;
	_leave(" = 0");
	return 0;

error:
	kernel_sock_shutdown(local->socket, SHUT_RDWR);
	local->socket->sk->sk_user_data = NULL;
	sock_release(local->socket);
	local->socket = NULL;

	_leave(" = %d", ret);
	return ret;
}

/*
 * create a new local endpoint using the specified UDP address
 */
struct rxrpc_local *rxrpc_lookup_local(struct sockaddr_rxrpc *srx)
{
	struct rxrpc_local *local;
	int ret;

	_enter("{%d,%u,%pI4+%hu}",
	       srx->transport_type,
	       srx->transport.family,
	       &srx->transport.sin.sin_addr,
	       ntohs(srx->transport.sin.sin_port));

	down_write(&rxrpc_local_sem);

	/* see if we have a suitable local local endpoint already */
	read_lock_bh(&rxrpc_local_lock);

	list_for_each_entry(local, &rxrpc_locals, link) {
		_debug("CMP {%d,%u,%pI4+%hu}",
		       local->srx.transport_type,
		       local->srx.transport.family,
		       &local->srx.transport.sin.sin_addr,
		       ntohs(local->srx.transport.sin.sin_port));

		if (local->srx.transport_type != srx->transport_type ||
		    local->srx.transport.family != srx->transport.family)
			continue;

		switch (srx->transport.family) {
		case AF_INET:
			if (local->srx.transport.sin.sin_port !=
			    srx->transport.sin.sin_port)
				continue;
			if (memcmp(&local->srx.transport.sin.sin_addr,
				   &srx->transport.sin.sin_addr,
				   sizeof(struct in_addr)) != 0)
				continue;
			goto found_local;

		default:
			BUG();
		}
	}

	read_unlock_bh(&rxrpc_local_lock);

	/* we didn't find one, so we need to create one */
	local = rxrpc_alloc_local(srx);
	if (!local) {
		up_write(&rxrpc_local_sem);
		return ERR_PTR(-ENOMEM);
	}

	ret = rxrpc_create_local(local);
	if (ret < 0) {
		up_write(&rxrpc_local_sem);
		kfree(local);
		_leave(" = %d", ret);
		return ERR_PTR(ret);
	}

	up_write(&rxrpc_local_sem);

	_net("LOCAL new %d {%d,%u,%pI4+%hu}",
	     local->debug_id,
	     local->srx.transport_type,
	     local->srx.transport.family,
	     &local->srx.transport.sin.sin_addr,
	     ntohs(local->srx.transport.sin.sin_port));

	_leave(" = %p [new]", local);
	return local;

found_local:
	rxrpc_get_local(local);
	read_unlock_bh(&rxrpc_local_lock);
	up_write(&rxrpc_local_sem);

	_net("LOCAL old %d {%d,%u,%pI4+%hu}",
	     local->debug_id,
	     local->srx.transport_type,
	     local->srx.transport.family,
	     &local->srx.transport.sin.sin_addr,
	     ntohs(local->srx.transport.sin.sin_port));

	_leave(" = %p [reuse]", local);
	return local;
}

/*
 * release a local endpoint
 */
void rxrpc_put_local(struct rxrpc_local *local)
{
	_enter("%p{u=%d}", local, atomic_read(&local->usage));

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

	/* to prevent a race, the decrement and the dequeue must be effectively
	 * atomic */
	write_lock_bh(&rxrpc_local_lock);
	if (unlikely(atomic_dec_and_test(&local->usage))) {
		_debug("destroy local");
		rxrpc_queue_work(&local->destroyer);
	}
	write_unlock_bh(&rxrpc_local_lock);
	_leave("");
}

/*
 * destroy a local endpoint
 */
static void rxrpc_destroy_local(struct work_struct *work)
{
	struct rxrpc_local *local =
		container_of(work, struct rxrpc_local, destroyer);

	_enter("%p{%d}", local, atomic_read(&local->usage));

	down_write(&rxrpc_local_sem);

	write_lock_bh(&rxrpc_local_lock);
	if (atomic_read(&local->usage) > 0) {
		write_unlock_bh(&rxrpc_local_lock);
		up_read(&rxrpc_local_sem);
		_leave(" [resurrected]");
		return;
	}

	list_del(&local->link);
	local->socket->sk->sk_user_data = NULL;
	write_unlock_bh(&rxrpc_local_lock);

	downgrade_write(&rxrpc_local_sem);

	ASSERT(list_empty(&local->services));
	ASSERT(!work_pending(&local->acceptor));
	ASSERT(!work_pending(&local->rejecter));

	/* finish cleaning up the local descriptor */
	rxrpc_purge_queue(&local->accept_queue);
	rxrpc_purge_queue(&local->reject_queue);
	kernel_sock_shutdown(local->socket, SHUT_RDWR);
	sock_release(local->socket);

	up_read(&rxrpc_local_sem);

	_net("DESTROY LOCAL %d", local->debug_id);
	kfree(local);

	if (list_empty(&rxrpc_locals))
		wake_up_all(&rxrpc_local_wq);

	_leave("");
}

/*
 * preemptively destroy all local local endpoint rather than waiting for
 * them to be destroyed
 */
void __exit rxrpc_destroy_all_locals(void)
{
	DECLARE_WAITQUEUE(myself,current);

	_enter("");

	/* we simply have to wait for them to go away */
	if (!list_empty(&rxrpc_locals)) {
		set_current_state(TASK_UNINTERRUPTIBLE);
		add_wait_queue(&rxrpc_local_wq, &myself);

		while (!list_empty(&rxrpc_locals)) {
			schedule();
			set_current_state(TASK_UNINTERRUPTIBLE);
		}

		remove_wait_queue(&rxrpc_local_wq, &myself);
		set_current_state(TASK_RUNNING);
	}

	_leave("");
}
Commit	Line	Data
17926a79 DH	1	/* AF_RXRPC local endpoint management
	2	*
	3	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells ([email protected])
	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 LIST_HEAD(rxrpc_locals);
	21	DEFINE_RWLOCK(rxrpc_local_lock);
	22	static DECLARE_RWSEM(rxrpc_local_sem);
	23	static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq);
	24
	25	static void rxrpc_destroy_local(struct work_struct *work);
	26
	27	/*
	28	* allocate a new local
	29	*/
	30	static
	31	struct rxrpc_local rxrpc_alloc_local(struct sockaddr_rxrpc srx)
	32	{
	33	struct rxrpc_local *local;
	34
	35	local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
	36	if (local) {
	37	INIT_WORK(&local->destroyer, &rxrpc_destroy_local);
	38	INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls);
	39	INIT_WORK(&local->rejecter, &rxrpc_reject_packets);
	40	INIT_LIST_HEAD(&local->services);
	41	INIT_LIST_HEAD(&local->link);
	42	init_rwsem(&local->defrag_sem);
	43	skb_queue_head_init(&local->accept_queue);
	44	skb_queue_head_init(&local->reject_queue);
	45	spin_lock_init(&local->lock);
	46	rwlock_init(&local->services_lock);
	47	atomic_set(&local->usage, 1);
	48	local->debug_id = atomic_inc_return(&rxrpc_debug_id);
	49	memcpy(&local->srx, srx, sizeof(*srx));
	50	}
	51
	52	_leave(" = %p", local);
	53	return local;
	54	}
	55
	56	/*
	57	* create the local socket
	58	* - must be called with rxrpc_local_sem writelocked
	59	*/
	60	static int rxrpc_create_local(struct rxrpc_local *local)
	61	{
	62	struct sock *sock;
	63	int ret, opt;
	64
	65	_enter("%p{%d}", local, local->srx.transport_type);
	66
	67	/* create a socket to represent the local endpoint */
	68	ret = sock_create_kern(PF_INET, local->srx.transport_type, IPPROTO_UDP,
	69	&local->socket);
	70	if (ret < 0) {
	71	_leave(" = %d [socket]", ret);
	72	return ret;
	73	}
	74
	75	/* if a local address was supplied then bind it */
	76	if (local->srx.transport_len > sizeof(sa_family_t)) {
	77	_debug("bind");
	78	ret = kernel_bind(local->socket,
	79	(struct sockaddr *) &local->srx.transport,
80	local->srx.transport_len);
81	if (ret < 0) {
82	_debug("bind failed");
83	goto error;
84	}
85	}
86
87	/* we want to receive ICMP errors */
88	opt = 1;
89	ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
90	(char *) &opt, sizeof(opt));
91	if (ret < 0) {
92	_debug("setsockopt failed");
93	goto error;
94	}
95
96	/* we want to set the don't fragment bit */
97	opt = IP_PMTUDISC_DO;
98	ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
99	(char *) &opt, sizeof(opt));
100	if (ret < 0) {
101	_debug("setsockopt failed");
102	goto error;
103	}
104
105	write_lock_bh(&rxrpc_local_lock);
106	list_add(&local->link, &rxrpc_locals);
107	write_unlock_bh(&rxrpc_local_lock);
108
109	/* set the socket up */
110	sock = local->socket->sk;
111	sock->sk_user_data = local;
112	sock->sk_data_ready = rxrpc_data_ready;
113	sock->sk_error_report = rxrpc_UDP_error_report;
114	_leave(" = 0");
115	return 0;
116
117	error:
91cf45f0	118	kernel_sock_shutdown(local->socket, SHUT_RDWR);
17926a79 DH	119	local->socket->sk->sk_user_data = NULL;
	120	sock_release(local->socket);
	121	local->socket = NULL;
	122
	123	_leave(" = %d", ret);
	124	return ret;
	125	}
	126
	127	/*
	128	* create a new local endpoint using the specified UDP address
	129	*/
	130	struct rxrpc_local rxrpc_lookup_local(struct sockaddr_rxrpc srx)
	131	{
	132	struct rxrpc_local *local;
	133	int ret;
	134
21454aaa	135	_enter("{%d,%u,%pI4+%hu}",
17926a79 DH	136	srx->transport_type,
17926a79 DH	137	srx->transport.family,
21454aaa	138	&srx->transport.sin.sin_addr,
17926a79 DH	139	ntohs(srx->transport.sin.sin_port));
	140
	141	down_write(&rxrpc_local_sem);
	142
	143	/* see if we have a suitable local local endpoint already */
	144	read_lock_bh(&rxrpc_local_lock);
	145
	146	list_for_each_entry(local, &rxrpc_locals, link) {
21454aaa	147	_debug("CMP {%d,%u,%pI4+%hu}",
17926a79 DH	148	local->srx.transport_type,
17926a79 DH	149	local->srx.transport.family,
21454aaa	150	&local->srx.transport.sin.sin_addr,
17926a79 DH	151	ntohs(local->srx.transport.sin.sin_port));
	152
	153	if (local->srx.transport_type != srx->transport_type \|\|
	154	local->srx.transport.family != srx->transport.family)
	155	continue;
	156
	157	switch (srx->transport.family) {
	158	case AF_INET:
	159	if (local->srx.transport.sin.sin_port !=
	160	srx->transport.sin.sin_port)
	161	continue;
	162	if (memcmp(&local->srx.transport.sin.sin_addr,
	163	&srx->transport.sin.sin_addr,
	164	sizeof(struct in_addr)) != 0)
	165	continue;
	166	goto found_local;
	167
	168	default:
	169	BUG();
	170	}
	171	}
	172
	173	read_unlock_bh(&rxrpc_local_lock);
	174
	175	/* we didn't find one, so we need to create one */
	176	local = rxrpc_alloc_local(srx);
	177	if (!local) {
	178	up_write(&rxrpc_local_sem);
	179	return ERR_PTR(-ENOMEM);
	180	}
	181
	182	ret = rxrpc_create_local(local);
	183	if (ret < 0) {
	184	up_write(&rxrpc_local_sem);
	185	kfree(local);
	186	_leave(" = %d", ret);
	187	return ERR_PTR(ret);
	188	}
	189
	190	up_write(&rxrpc_local_sem);
	191
21454aaa	192	_net("LOCAL new %d {%d,%u,%pI4+%hu}",
17926a79 DH	193	local->debug_id,
	194	local->srx.transport_type,
	195	local->srx.transport.family,
21454aaa	196	&local->srx.transport.sin.sin_addr,
17926a79 DH	197	ntohs(local->srx.transport.sin.sin_port));
	198
	199	_leave(" = %p [new]", local);
	200	return local;
	201
	202	found_local:
	203	rxrpc_get_local(local);
	204	read_unlock_bh(&rxrpc_local_lock);
	205	up_write(&rxrpc_local_sem);
	206
21454aaa	207	_net("LOCAL old %d {%d,%u,%pI4+%hu}",
17926a79 DH	208	local->debug_id,
	209	local->srx.transport_type,
	210	local->srx.transport.family,
21454aaa	211	&local->srx.transport.sin.sin_addr,
17926a79 DH	212	ntohs(local->srx.transport.sin.sin_port));
	213
	214	_leave(" = %p [reuse]", local);
	215	return local;
	216	}
	217
	218	/*
	219	* release a local endpoint
	220	*/
	221	void rxrpc_put_local(struct rxrpc_local *local)
	222	{
	223	_enter("%p{u=%d}", local, atomic_read(&local->usage));
	224
	225	ASSERTCMP(atomic_read(&local->usage), >, 0);
	226
	227	/* to prevent a race, the decrement and the dequeue must be effectively
	228	* atomic */
	229	write_lock_bh(&rxrpc_local_lock);
	230	if (unlikely(atomic_dec_and_test(&local->usage))) {
	231	_debug("destroy local");
651350d1	232	rxrpc_queue_work(&local->destroyer);
17926a79 DH	233	}
	234	write_unlock_bh(&rxrpc_local_lock);
	235	_leave("");
	236	}
	237
	238	/*
	239	* destroy a local endpoint
	240	*/
	241	static void rxrpc_destroy_local(struct work_struct *work)
	242	{
	243	struct rxrpc_local *local =
	244	container_of(work, struct rxrpc_local, destroyer);
	245
	246	_enter("%p{%d}", local, atomic_read(&local->usage));
	247
	248	down_write(&rxrpc_local_sem);
	249
	250	write_lock_bh(&rxrpc_local_lock);
	251	if (atomic_read(&local->usage) > 0) {
	252	write_unlock_bh(&rxrpc_local_lock);
	253	up_read(&rxrpc_local_sem);
	254	_leave(" [resurrected]");
	255	return;
	256	}
	257
	258	list_del(&local->link);
	259	local->socket->sk->sk_user_data = NULL;
	260	write_unlock_bh(&rxrpc_local_lock);
	261
	262	downgrade_write(&rxrpc_local_sem);
	263
	264	ASSERT(list_empty(&local->services));
	265	ASSERT(!work_pending(&local->acceptor));
	266	ASSERT(!work_pending(&local->rejecter));
	267
	268	/* finish cleaning up the local descriptor */
	269	rxrpc_purge_queue(&local->accept_queue);
	270	rxrpc_purge_queue(&local->reject_queue);
91cf45f0	271	kernel_sock_shutdown(local->socket, SHUT_RDWR);
17926a79 DH	272	sock_release(local->socket);
	273
	274	up_read(&rxrpc_local_sem);
	275
	276	_net("DESTROY LOCAL %d", local->debug_id);
	277	kfree(local);
	278
	279	if (list_empty(&rxrpc_locals))
	280	wake_up_all(&rxrpc_local_wq);
	281
	282	_leave("");
	283	}
	284
	285	/*
	286	* preemptively destroy all local local endpoint rather than waiting for
	287	* them to be destroyed
	288	*/
	289	void __exit rxrpc_destroy_all_locals(void)
	290	{
	291	DECLARE_WAITQUEUE(myself,current);
	292
	293	_enter("");
	294
	295	/* we simply have to wait for them to go away */
	296	if (!list_empty(&rxrpc_locals)) {
	297	set_current_state(TASK_UNINTERRUPTIBLE);
	298	add_wait_queue(&rxrpc_local_wq, &myself);
	299
	300	while (!list_empty(&rxrpc_locals)) {
	301	schedule();
	302	set_current_state(TASK_UNINTERRUPTIBLE);
	303	}
	304
	305	remove_wait_queue(&rxrpc_local_wq, &myself);
	306	set_current_state(TASK_RUNNING);
	307	}
	308
	309	_leave("");
	310	}