[net-next-2.6.git] / drivers / connector / connector.c

/*
 * 	connector.c
 * 
 * 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
 * All rights reserved.
 * 
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/moduleparam.h>
#include <linux/connector.h>
#include <linux/mutex.h>

#include <net/sock.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");

static u32 cn_idx = CN_IDX_CONNECTOR;
static u32 cn_val = CN_VAL_CONNECTOR;

module_param(cn_idx, uint, 0);
module_param(cn_val, uint, 0);
MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
MODULE_PARM_DESC(cn_val, "Connector's main device val.");

static DEFINE_MUTEX(notify_lock);
static LIST_HEAD(notify_list);

static struct cn_dev cdev;

int cn_already_initialized = 0;

/*
 * msg->seq and msg->ack are used to determine message genealogy.
 * When someone sends message it puts there locally unique sequence
 * and random acknowledge numbers.  Sequence number may be copied into
 * nlmsghdr->nlmsg_seq too.
 *
 * Sequence number is incremented with each message to be sent.
 *
 * If we expect reply to our message then the sequence number in
 * received message MUST be the same as in original message, and
 * acknowledge number MUST be the same + 1.
 *
 * If we receive a message and its sequence number is not equal to the
 * one we are expecting then it is a new message.
 *
 * If we receive a message and its sequence number is the same as one
 * we are expecting but it's acknowledgement number is not equal to
 * the acknowledgement number in the original message + 1, then it is
 * a new message.
 *
 */
int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask)
{
	struct cn_callback_entry *__cbq;
	unsigned int size;
	struct sk_buff *skb;
	struct nlmsghdr *nlh;
	struct cn_msg *data;
	struct cn_dev *dev = &cdev;
	u32 group = 0;
	int found = 0;

	if (!__group) {
		spin_lock_bh(&dev->cbdev->queue_lock);
		list_for_each_entry(__cbq, &dev->cbdev->queue_list,
				    callback_entry) {
			if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
				found = 1;
				group = __cbq->group;
			}
		}
		spin_unlock_bh(&dev->cbdev->queue_lock);

		if (!found)
			return -ENODEV;
	} else {
		group = __group;
	}

	if (!netlink_has_listeners(dev->nls, group))
		return -ESRCH;

	size = NLMSG_SPACE(sizeof(*msg) + msg->len);

	skb = alloc_skb(size, gfp_mask);
	if (!skb)
		return -ENOMEM;

	nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));

	data = NLMSG_DATA(nlh);

	memcpy(data, msg, sizeof(*data) + msg->len);

	NETLINK_CB(skb).dst_group = group;

	return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);

nlmsg_failure:
	kfree_skb(skb);
	return -EINVAL;
}

/*
 * Callback helper - queues work and setup destructor for given data.
 */
static int cn_call_callback(struct cn_msg *msg, void (*destruct_data)(void *), void *data)
{
	struct cn_callback_entry *__cbq;
	struct cn_dev *dev = &cdev;
	int err = -ENODEV;

	spin_lock_bh(&dev->cbdev->queue_lock);
	list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
		if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
			if (likely(!test_bit(0, &__cbq->work.pending) &&
					__cbq->data.ddata == NULL)) {
				__cbq->data.callback_priv = msg;

				__cbq->data.ddata = data;
				__cbq->data.destruct_data = destruct_data;

				if (queue_work(dev->cbdev->cn_queue,
						&__cbq->work))
					err = 0;
			} else {
				struct work_struct *w;
				struct cn_callback_data *d;
				
				w = kzalloc(sizeof(*w) + sizeof(*d), GFP_ATOMIC);
				if (w) {
					d = (struct cn_callback_data *)(w+1);

					d->callback_priv = msg;
					d->callback = __cbq->data.callback;
					d->ddata = data;
					d->destruct_data = destruct_data;
					d->free = w;

					INIT_LIST_HEAD(&w->entry);
					w->pending = 0;
					w->func = &cn_queue_wrapper;
					w->data = d;
					init_timer(&w->timer);
					
					if (queue_work(dev->cbdev->cn_queue, w))
						err = 0;
					else {
						kfree(w);
						err = -EINVAL;
					}
				} else
					err = -ENOMEM;
			}
			break;
		}
	}
	spin_unlock_bh(&dev->cbdev->queue_lock);

	return err;
}

/*
 * Skb receive helper - checks skb and msg size and calls callback
 * helper.
 */
static int __cn_rx_skb(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	u32 pid, uid, seq, group;
	struct cn_msg *msg;

	pid = NETLINK_CREDS(skb)->pid;
	uid = NETLINK_CREDS(skb)->uid;
	seq = nlh->nlmsg_seq;
	group = NETLINK_CB((skb)).dst_group;
	msg = NLMSG_DATA(nlh);

	return cn_call_callback(msg, (void (*)(void *))kfree_skb, skb);
}

/*
 * Main netlink receiving function.
 *
 * It checks skb and netlink header sizes and calls the skb receive
 * helper with a shared skb.
 */
static void cn_rx_skb(struct sk_buff *__skb)
{
	struct nlmsghdr *nlh;
	u32 len;
	int err;
	struct sk_buff *skb;

	skb = skb_get(__skb);

	if (skb->len >= NLMSG_SPACE(0)) {
		nlh = (struct nlmsghdr *)skb->data;

		if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
		    skb->len < nlh->nlmsg_len ||
		    nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
			kfree_skb(skb);
			goto out;
		}

		len = NLMSG_ALIGN(nlh->nlmsg_len);
		if (len > skb->len)
			len = skb->len;

		err = __cn_rx_skb(skb, nlh);
		if (err < 0)
			kfree_skb(skb);
	}

out:
	kfree_skb(__skb);
}

/*
 * Netlink socket input callback - dequeues the skbs and calls the
 * main netlink receiving function.
 */
static void cn_input(struct sock *sk, int len)
{
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL)
		cn_rx_skb(skb);
}

/*
 * Notification routing.
 *
 * Gets id and checks if there are notification request for it's idx
 * and val.  If there are such requests notify the listeners with the
 * given notify event.
 *
 */
static void cn_notify(struct cb_id *id, u32 notify_event)
{
	struct cn_ctl_entry *ent;

	mutex_lock(&notify_lock);
	list_for_each_entry(ent, &notify_list, notify_entry) {
		int i;
		struct cn_notify_req *req;
		struct cn_ctl_msg *ctl = ent->msg;
		int idx_found, val_found;

		idx_found = val_found = 0;

		req = (struct cn_notify_req *)ctl->data;
		for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
			if (id->idx >= req->first && 
					id->idx < req->first + req->range) {
				idx_found = 1;
				break;
			}
		}

		for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
			if (id->val >= req->first && 
					id->val < req->first + req->range) {
				val_found = 1;
				break;
			}
		}

		if (idx_found && val_found) {
			struct cn_msg m = { .ack = notify_event, };

			memcpy(&m.id, id, sizeof(m.id));
			cn_netlink_send(&m, ctl->group, GFP_KERNEL);
		}
	}
	mutex_unlock(&notify_lock);
}

/*
 * Callback add routing - adds callback with given ID and name.
 * If there is registered callback with the same ID it will not be added.
 *
 * May sleep.
 */
int cn_add_callback(struct cb_id *id, char *name, void (*callback)(void *))
{
	int err;
	struct cn_dev *dev = &cdev;

	err = cn_queue_add_callback(dev->cbdev, name, id, callback);
	if (err)
		return err;

	cn_notify(id, 0);

	return 0;
}

/*
 * Callback remove routing - removes callback
 * with given ID.
 * If there is no registered callback with given
 * ID nothing happens.
 *
 * May sleep while waiting for reference counter to become zero.
 */
void cn_del_callback(struct cb_id *id)
{
	struct cn_dev *dev = &cdev;

	cn_queue_del_callback(dev->cbdev, id);
	cn_notify(id, 1);
}

/*
 * Checks two connector's control messages to be the same.
 * Returns 1 if they are the same or if the first one is corrupted.
 */
static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2)
{
	int i;
	struct cn_notify_req *req1, *req2;

	if (m1->idx_notify_num != m2->idx_notify_num)
		return 0;

	if (m1->val_notify_num != m2->val_notify_num)
		return 0;

	if (m1->len != m2->len)
		return 0;

	if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
	    m1->len)
		return 1;

	req1 = (struct cn_notify_req *)m1->data;
	req2 = (struct cn_notify_req *)m2->data;

	for (i = 0; i < m1->idx_notify_num; ++i) {
		if (req1->first != req2->first || req1->range != req2->range)
			return 0;
		req1++;
		req2++;
	}

	for (i = 0; i < m1->val_notify_num; ++i) {
		if (req1->first != req2->first || req1->range != req2->range)
			return 0;
		req1++;
		req2++;
	}

	return 1;
}

/*
 * Main connector device's callback.
 *
 * Used for notification of a request's processing.
 */
static void cn_callback(void *data)
{
	struct cn_msg *msg = data;
	struct cn_ctl_msg *ctl;
	struct cn_ctl_entry *ent;
	u32 size;

	if (msg->len < sizeof(*ctl))
		return;

	ctl = (struct cn_ctl_msg *)msg->data;

	size = (sizeof(*ctl) + ((ctl->idx_notify_num +
				 ctl->val_notify_num) *
				sizeof(struct cn_notify_req)));

	if (msg->len != size)
		return;

	if (ctl->len + sizeof(*ctl) != msg->len)
		return;

	/*
	 * Remove notification.
	 */
	if (ctl->group == 0) {
		struct cn_ctl_entry *n;

		mutex_lock(&notify_lock);
		list_for_each_entry_safe(ent, n, &notify_list, notify_entry) {
			if (cn_ctl_msg_equals(ent->msg, ctl)) {
				list_del(&ent->notify_entry);
				kfree(ent);
			}
		}
		mutex_unlock(&notify_lock);

		return;
	}

	size += sizeof(*ent);

	ent = kzalloc(size, GFP_KERNEL);
	if (!ent)
		return;

	ent->msg = (struct cn_ctl_msg *)(ent + 1);

	memcpy(ent->msg, ctl, size - sizeof(*ent));

	mutex_lock(&notify_lock);
	list_add(&ent->notify_entry, &notify_list);
	mutex_unlock(&notify_lock);
}

static int __init cn_init(void)
{
	struct cn_dev *dev = &cdev;
	int err;

	dev->input = cn_input;
	dev->id.idx = cn_idx;
	dev->id.val = cn_val;

	dev->nls = netlink_kernel_create(NETLINK_CONNECTOR,
					 CN_NETLINK_USERS + 0xf,
					 dev->input, THIS_MODULE);
	if (!dev->nls)
		return -EIO;

	dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
	if (!dev->cbdev) {
		if (dev->nls->sk_socket)
			sock_release(dev->nls->sk_socket);
		return -EINVAL;
	}

	err = cn_add_callback(&dev->id, "connector", &cn_callback);
	if (err) {
		cn_queue_free_dev(dev->cbdev);
		if (dev->nls->sk_socket)
			sock_release(dev->nls->sk_socket);
		return -EINVAL;
	}

	cn_already_initialized = 1;

	return 0;
}

static void __exit cn_fini(void)
{
	struct cn_dev *dev = &cdev;

	cn_already_initialized = 0;

	cn_del_callback(&dev->id);
	cn_queue_free_dev(dev->cbdev);
	if (dev->nls->sk_socket)
		sock_release(dev->nls->sk_socket);
}

module_init(cn_init);
module_exit(cn_fini);

EXPORT_SYMBOL_GPL(cn_add_callback);
EXPORT_SYMBOL_GPL(cn_del_callback);
EXPORT_SYMBOL_GPL(cn_netlink_send);
Commit	Line	Data
7672d0b5 EP	1	/*
	2	* connector.c
	3	*
	4	* 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
	5	* All rights reserved.
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*/
	21
	22	#include <linux/kernel.h>
	23	#include <linux/module.h>
	24	#include <linux/list.h>
	25	#include <linux/skbuff.h>
	26	#include <linux/netlink.h>
	27	#include <linux/moduleparam.h>
	28	#include <linux/connector.h>
8ed965d6	29	#include <linux/mutex.h>
7672d0b5 EP	30
	31	#include <net/sock.h>
	32
	33	MODULE_LICENSE("GPL");
	34	MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
	35	MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
	36
	37	static u32 cn_idx = CN_IDX_CONNECTOR;
	38	static u32 cn_val = CN_VAL_CONNECTOR;
	39
	40	module_param(cn_idx, uint, 0);
	41	module_param(cn_val, uint, 0);
	42	MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
	43	MODULE_PARM_DESC(cn_val, "Connector's main device val.");
	44
8ed965d6	45	static DEFINE_MUTEX(notify_lock);
7672d0b5 EP	46	static LIST_HEAD(notify_list);
	47
	48	static struct cn_dev cdev;
	49
	50	int cn_already_initialized = 0;
	51
	52	/*
	53	* msg->seq and msg->ack are used to determine message genealogy.
	54	* When someone sends message it puts there locally unique sequence
	55	* and random acknowledge numbers. Sequence number may be copied into
	56	* nlmsghdr->nlmsg_seq too.
	57	*
	58	* Sequence number is incremented with each message to be sent.
	59	*
	60	* If we expect reply to our message then the sequence number in
	61	* received message MUST be the same as in original message, and
	62	* acknowledge number MUST be the same + 1.
	63	*
	64	* If we receive a message and its sequence number is not equal to the
	65	* one we are expecting then it is a new message.
	66	*
	67	* If we receive a message and its sequence number is the same as one
	68	* we are expecting but it's acknowledgement number is not equal to
	69	* the acknowledgement number in the original message + 1, then it is
	70	* a new message.
	71	*
	72	*/
dd0fc66f	73	int cn_netlink_send(struct cn_msg *msg, u32 __group, gfp_t gfp_mask)
7672d0b5 EP	74	{
	75	struct cn_callback_entry *__cbq;
	76	unsigned int size;
	77	struct sk_buff *skb;
	78	struct nlmsghdr *nlh;
	79	struct cn_msg *data;
	80	struct cn_dev *dev = &cdev;
	81	u32 group = 0;
	82	int found = 0;
	83
	84	if (!__group) {
	85	spin_lock_bh(&dev->cbdev->queue_lock);
	86	list_for_each_entry(__cbq, &dev->cbdev->queue_list,
	87	callback_entry) {
acd042bb	88	if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
7672d0b5 EP	89	found = 1;
	90	group = __cbq->group;
	91	}
	92	}
	93	spin_unlock_bh(&dev->cbdev->queue_lock);
	94
	95	if (!found)
	96	return -ENODEV;
	97	} else {
	98	group = __group;
	99	}
	100
b191ba0d EP	101	if (!netlink_has_listeners(dev->nls, group))
	102	return -ESRCH;
	103
7672d0b5 EP	104	size = NLMSG_SPACE(sizeof(*msg) + msg->len);
	105
	106	skb = alloc_skb(size, gfp_mask);
	107	if (!skb)
	108	return -ENOMEM;
	109
	110	nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
	111
	112	data = NLMSG_DATA(nlh);
	113
	114	memcpy(data, msg, sizeof(*data) + msg->len);
	115
	116	NETLINK_CB(skb).dst_group = group;
	117
b191ba0d	118	return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
7672d0b5 EP	119
	120	nlmsg_failure:
	121	kfree_skb(skb);
	122	return -EINVAL;
	123	}
	124
	125	/*
	126	* Callback helper - queues work and setup destructor for given data.
	127	*/
	128	static int cn_call_callback(struct cn_msg msg, void (destruct_data)(void ), void data)
	129	{
	130	struct cn_callback_entry *__cbq;
	131	struct cn_dev *dev = &cdev;
acd042bb	132	int err = -ENODEV;
7672d0b5 EP	133
	134	spin_lock_bh(&dev->cbdev->queue_lock);
	135	list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
acd042bb	136	if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
7672d0b5	137	if (likely(!test_bit(0, &__cbq->work.pending) &&
acd042bb EP	138	__cbq->data.ddata == NULL)) {
acd042bb EP	139	__cbq->data.callback_priv = msg;
7672d0b5	140
acd042bb EP	141	__cbq->data.ddata = data;
acd042bb EP	142	__cbq->data.destruct_data = destruct_data;
7672d0b5 EP	143
	144	if (queue_work(dev->cbdev->cn_queue,
	145	&__cbq->work))
acd042bb	146	err = 0;
7672d0b5	147	} else {
acd042bb EP	148	struct work_struct *w;
	149	struct cn_callback_data *d;
	150
	151	w = kzalloc(sizeof(w) + sizeof(d), GFP_ATOMIC);
	152	if (w) {
	153	d = (struct cn_callback_data *)(w+1);
	154
	155	d->callback_priv = msg;
	156	d->callback = __cbq->data.callback;
	157	d->ddata = data;
	158	d->destruct_data = destruct_data;
	159	d->free = w;
	160
	161	INIT_LIST_HEAD(&w->entry);
	162	w->pending = 0;
	163	w->func = &cn_queue_wrapper;
	164	w->data = d;
	165	init_timer(&w->timer);
	166
	167	if (queue_work(dev->cbdev->cn_queue, w))
	168	err = 0;
	169	else {
	170	kfree(w);
	171	err = -EINVAL;
	172	}
	173	} else
	174	err = -ENOMEM;
7672d0b5 EP	175	}
	176	break;
	177	}
	178	}
	179	spin_unlock_bh(&dev->cbdev->queue_lock);
	180
acd042bb	181	return err;
7672d0b5 EP	182	}
	183
	184	/*
	185	* Skb receive helper - checks skb and msg size and calls callback
	186	* helper.
	187	*/
	188	static int __cn_rx_skb(struct sk_buff skb, struct nlmsghdr nlh)
	189	{
	190	u32 pid, uid, seq, group;
	191	struct cn_msg *msg;
	192
	193	pid = NETLINK_CREDS(skb)->pid;
	194	uid = NETLINK_CREDS(skb)->uid;
	195	seq = nlh->nlmsg_seq;
	196	group = NETLINK_CB((skb)).dst_group;
	197	msg = NLMSG_DATA(nlh);
	198
	199	return cn_call_callback(msg, (void ()(void ))kfree_skb, skb);
	200	}
	201
	202	/*
	203	* Main netlink receiving function.
	204	*
	205	* It checks skb and netlink header sizes and calls the skb receive
	206	* helper with a shared skb.
	207	*/
	208	static void cn_rx_skb(struct sk_buff *__skb)
	209	{
	210	struct nlmsghdr *nlh;
	211	u32 len;
	212	int err;
	213	struct sk_buff *skb;
	214
	215	skb = skb_get(__skb);
	216
	217	if (skb->len >= NLMSG_SPACE(0)) {
	218	nlh = (struct nlmsghdr *)skb->data;
	219
	220	if (nlh->nlmsg_len < sizeof(struct cn_msg) \|\|
	221	skb->len < nlh->nlmsg_len \|\|
	222	nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
	223	kfree_skb(skb);
	224	goto out;
	225	}
	226
	227	len = NLMSG_ALIGN(nlh->nlmsg_len);
	228	if (len > skb->len)
	229	len = skb->len;
	230
	231	err = __cn_rx_skb(skb, nlh);
	232	if (err < 0)
	233	kfree_skb(skb);
	234	}
	235
	236	out:
	237	kfree_skb(__skb);
	238	}
	239
	240	/*
	241	* Netlink socket input callback - dequeues the skbs and calls the
	242	* main netlink receiving function.
	243	*/
	244	static void cn_input(struct sock *sk, int len)
	245	{
246	struct sk_buff *skb;
247
248	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL)
249	cn_rx_skb(skb);
250	}
251
252	/*
253	* Notification routing.
254	*
255	* Gets id and checks if there are notification request for it's idx
256	* and val. If there are such requests notify the listeners with the
257	* given notify event.
258	*
259	*/
260	static void cn_notify(struct cb_id *id, u32 notify_event)
261	{
262	struct cn_ctl_entry *ent;
263
8ed965d6	264	mutex_lock(&notify_lock);
7672d0b5 EP	265	list_for_each_entry(ent, &notify_list, notify_entry) {
	266	int i;
	267	struct cn_notify_req *req;
	268	struct cn_ctl_msg *ctl = ent->msg;
	269	int idx_found, val_found;
	270
	271	idx_found = val_found = 0;
	272
	273	req = (struct cn_notify_req *)ctl->data;
	274	for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
	275	if (id->idx >= req->first &&
	276	id->idx < req->first + req->range) {
	277	idx_found = 1;
	278	break;
	279	}
	280	}
	281
	282	for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
	283	if (id->val >= req->first &&
	284	id->val < req->first + req->range) {
	285	val_found = 1;
	286	break;
	287	}
	288	}
	289
	290	if (idx_found && val_found) {
	291	struct cn_msg m = { .ack = notify_event, };
	292
	293	memcpy(&m.id, id, sizeof(m.id));
	294	cn_netlink_send(&m, ctl->group, GFP_KERNEL);
	295	}
	296	}
8ed965d6	297	mutex_unlock(&notify_lock);
7672d0b5 EP	298	}
	299
	300	/*
	301	* Callback add routing - adds callback with given ID and name.
	302	* If there is registered callback with the same ID it will not be added.
	303	*
	304	* May sleep.
	305	*/
	306	int cn_add_callback(struct cb_id id, char name, void (callback)(void ))
	307	{
	308	int err;
	309	struct cn_dev *dev = &cdev;
7672d0b5	310
acd042bb EP	311	err = cn_queue_add_callback(dev->cbdev, name, id, callback);
acd042bb EP	312	if (err)
7672d0b5	313	return err;
7672d0b5 EP	314
	315	cn_notify(id, 0);
	316
	317	return 0;
	318	}
	319
	320	/*
	321	* Callback remove routing - removes callback
	322	* with given ID.
	323	* If there is no registered callback with given
	324	* ID nothing happens.
	325	*
	326	* May sleep while waiting for reference counter to become zero.
	327	*/
	328	void cn_del_callback(struct cb_id *id)
	329	{
	330	struct cn_dev *dev = &cdev;
	331
	332	cn_queue_del_callback(dev->cbdev, id);
	333	cn_notify(id, 1);
	334	}
	335
	336	/*
	337	* Checks two connector's control messages to be the same.
	338	* Returns 1 if they are the same or if the first one is corrupted.
	339	*/
	340	static int cn_ctl_msg_equals(struct cn_ctl_msg m1, struct cn_ctl_msg m2)
	341	{
	342	int i;
	343	struct cn_notify_req req1, req2;
	344
	345	if (m1->idx_notify_num != m2->idx_notify_num)
	346	return 0;
	347
	348	if (m1->val_notify_num != m2->val_notify_num)
	349	return 0;
	350
	351	if (m1->len != m2->len)
	352	return 0;
	353
	354	if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
	355	m1->len)
	356	return 1;
	357
	358	req1 = (struct cn_notify_req *)m1->data;
	359	req2 = (struct cn_notify_req *)m2->data;
	360
	361	for (i = 0; i < m1->idx_notify_num; ++i) {
	362	if (req1->first != req2->first \|\| req1->range != req2->range)
	363	return 0;
	364	req1++;
	365	req2++;
	366	}
	367
	368	for (i = 0; i < m1->val_notify_num; ++i) {
	369	if (req1->first != req2->first \|\| req1->range != req2->range)
	370	return 0;
	371	req1++;
	372	req2++;
	373	}
	374
	375	return 1;
	376	}
	377
378	/*
379	* Main connector device's callback.
380	*
381	* Used for notification of a request's processing.
382	*/
383	static void cn_callback(void *data)
384	{
385	struct cn_msg *msg = data;
386	struct cn_ctl_msg *ctl;
387	struct cn_ctl_entry *ent;
388	u32 size;
389
390	if (msg->len < sizeof(*ctl))
391	return;
392
393	ctl = (struct cn_ctl_msg *)msg->data;
394
395	size = (sizeof(*ctl) + ((ctl->idx_notify_num +
396	ctl->val_notify_num) *
397	sizeof(struct cn_notify_req)));
398
399	if (msg->len != size)
400	return;
401
402	if (ctl->len + sizeof(*ctl) != msg->len)
403	return;
404
405	/*
406	* Remove notification.
407	*/
408	if (ctl->group == 0) {
409	struct cn_ctl_entry *n;
410
8ed965d6	411	mutex_lock(&notify_lock);
7672d0b5 EP	412	list_for_each_entry_safe(ent, n, &notify_list, notify_entry) {
	413	if (cn_ctl_msg_equals(ent->msg, ctl)) {
	414	list_del(&ent->notify_entry);
	415	kfree(ent);
	416	}
	417	}
8ed965d6	418	mutex_unlock(&notify_lock);
7672d0b5 EP	419
	420	return;
	421	}
	422
	423	size += sizeof(*ent);
	424
	425	ent = kzalloc(size, GFP_KERNEL);
	426	if (!ent)
	427	return;
	428
	429	ent->msg = (struct cn_ctl_msg *)(ent + 1);
	430
	431	memcpy(ent->msg, ctl, size - sizeof(*ent));
	432
8ed965d6	433	mutex_lock(&notify_lock);
7672d0b5	434	list_add(&ent->notify_entry, &notify_list);
8ed965d6	435	mutex_unlock(&notify_lock);
7672d0b5 EP	436	}
	437
	438	static int __init cn_init(void)
	439	{
	440	struct cn_dev *dev = &cdev;
	441	int err;
	442
	443	dev->input = cn_input;
	444	dev->id.idx = cn_idx;
	445	dev->id.val = cn_val;
	446
	447	dev->nls = netlink_kernel_create(NETLINK_CONNECTOR,
	448	CN_NETLINK_USERS + 0xf,
	449	dev->input, THIS_MODULE);
	450	if (!dev->nls)
	451	return -EIO;
	452
	453	dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
	454	if (!dev->cbdev) {
	455	if (dev->nls->sk_socket)
	456	sock_release(dev->nls->sk_socket);
	457	return -EINVAL;
	458	}
	459
	460	err = cn_add_callback(&dev->id, "connector", &cn_callback);
	461	if (err) {
	462	cn_queue_free_dev(dev->cbdev);
	463	if (dev->nls->sk_socket)
	464	sock_release(dev->nls->sk_socket);
	465	return -EINVAL;
	466	}
	467
	468	cn_already_initialized = 1;
	469
	470	return 0;
	471	}
	472
	473	static void __exit cn_fini(void)
	474	{
	475	struct cn_dev *dev = &cdev;
	476
	477	cn_already_initialized = 0;
	478
	479	cn_del_callback(&dev->id);
	480	cn_queue_free_dev(dev->cbdev);
	481	if (dev->nls->sk_socket)
	482	sock_release(dev->nls->sk_socket);
	483	}
	484
	485	module_init(cn_init);
	486	module_exit(cn_fini);
	487
	488	EXPORT_SYMBOL_GPL(cn_add_callback);
	489	EXPORT_SYMBOL_GPL(cn_del_callback);
	490	EXPORT_SYMBOL_GPL(cn_netlink_send);