[linux.git] / drivers / connector / connector.c

/*
 * 	connector.c
 * 
 * 2004-2005 Copyright (c) Evgeniy Polyakov <[email protected]>
 * 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 <[email protected]>");
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;

static int cn_already_initialized;

/*
 * 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;
				break;
			}
		}
		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;
}
EXPORT_SYMBOL_GPL(cn_netlink_send);

/*
 * 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, *__new_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(!work_pending(&__cbq->work) &&
					__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
					err = -EINVAL;
			} else {
				struct cn_callback_data *d;
				
				err = -ENOMEM;
				__new_cbq = kzalloc(sizeof(struct cn_callback_entry), GFP_ATOMIC);
				if (__new_cbq) {
					d = &__new_cbq->data;
					d->callback_priv = msg;
					d->callback = __cbq->data.callback;
					d->ddata = data;
					d->destruct_data = destruct_data;
					d->free = __new_cbq;

					INIT_WORK(&__new_cbq->work,
							&cn_queue_wrapper);

					if (queue_work(dev->cbdev->cn_queue,
						    &__new_cbq->work))
						err = 0;
					else {
						kfree(__new_cbq);
						err = -EINVAL;
					}
				}
			}
			break;
		}
	}
	spin_unlock_bh(&dev->cbdev->queue_lock);

	return err;
}

/*
 * Main netlink receiving function.
 *
 * It checks skb, netlink header and msg sizes, and calls callback helper.
 */
static void cn_rx_skb(struct sk_buff *__skb)
{
	struct cn_msg *msg;
	struct nlmsghdr *nlh;
	int err;
	struct sk_buff *skb;

	skb = skb_get(__skb);

	if (skb->len >= NLMSG_SPACE(0)) {
		nlh = nlmsg_hdr(skb);

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

		msg = NLMSG_DATA(nlh);
		err = cn_call_callback(msg, (void (*)(void *))kfree_skb, skb);
		if (err < 0)
			kfree_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;

	if (!cn_already_initialized)
		return -EAGAIN;

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

	cn_notify(id, 0);

	return 0;
}
EXPORT_SYMBOL_GPL(cn_add_callback);

/*
 * 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);
}
EXPORT_SYMBOL_GPL(cn_del_callback);

/*
 * 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 __devinit cn_init(void)
{
	struct cn_dev *dev = &cdev;
	int err;

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

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

	dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
	if (!dev->cbdev) {
		netlink_kernel_release(dev->nls);
		return -EINVAL;
	}
	
	cn_already_initialized = 1;

	err = cn_add_callback(&dev->id, "connector", &cn_callback);
	if (err) {
		cn_already_initialized = 0;
		cn_queue_free_dev(dev->cbdev);
		netlink_kernel_release(dev->nls);
		return -EINVAL;
	}

	return 0;
}

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

	cn_already_initialized = 0;

	cn_del_callback(&dev->id);
	cn_queue_free_dev(dev->cbdev);
	netlink_kernel_release(dev->nls);
}

subsys_initcall(cn_init);
module_exit(cn_fini);
Commit	Line	Data
7672d0b5 EP	1	/*
	2	* connector.c
	3	*
	4	* 2004-2005 Copyright (c) Evgeniy Polyakov <[email protected]>
	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 <[email protected]>");
	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
78374676	50	static int cn_already_initialized;
7672d0b5 EP	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;
7672d0b5 EP	90	group = __cbq->group;
fd00eecc	91	break;
7672d0b5 EP	92	}
	93	}
	94	spin_unlock_bh(&dev->cbdev->queue_lock);
	95
	96	if (!found)
	97	return -ENODEV;
	98	} else {
	99	group = __group;
	100	}
	101
b191ba0d EP	102	if (!netlink_has_listeners(dev->nls, group))
	103	return -ESRCH;
	104
7672d0b5 EP	105	size = NLMSG_SPACE(sizeof(*msg) + msg->len);
	106
	107	skb = alloc_skb(size, gfp_mask);
	108	if (!skb)
	109	return -ENOMEM;
	110
	111	nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
	112
	113	data = NLMSG_DATA(nlh);
	114
	115	memcpy(data, msg, sizeof(*data) + msg->len);
	116
	117	NETLINK_CB(skb).dst_group = group;
	118
b191ba0d	119	return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
7672d0b5 EP	120
	121	nlmsg_failure:
	122	kfree_skb(skb);
	123	return -EINVAL;
	124	}
deb0e9b2	125	EXPORT_SYMBOL_GPL(cn_netlink_send);
7672d0b5 EP	126
	127	/*
	128	* Callback helper - queues work and setup destructor for given data.
	129	*/
	130	static int cn_call_callback(struct cn_msg msg, void (destruct_data)(void ), void data)
	131	{
05e52dd7	132	struct cn_callback_entry __cbq, __new_cbq;
7672d0b5	133	struct cn_dev *dev = &cdev;
acd042bb	134	int err = -ENODEV;
7672d0b5 EP	135
	136	spin_lock_bh(&dev->cbdev->queue_lock);
	137	list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
acd042bb	138	if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
a240d9f1	139	if (likely(!work_pending(&__cbq->work) &&
acd042bb EP	140	__cbq->data.ddata == NULL)) {
acd042bb EP	141	__cbq->data.callback_priv = msg;
7672d0b5	142
acd042bb EP	143	__cbq->data.ddata = data;
acd042bb EP	144	__cbq->data.destruct_data = destruct_data;
7672d0b5	145
a240d9f1 EP	146	if (queue_work(dev->cbdev->cn_queue,
a240d9f1 EP	147	&__cbq->work))
acd042bb	148	err = 0;
134d99e3 LZ	149	else
134d99e3 LZ	150	err = -EINVAL;
7672d0b5	151	} else {
acd042bb EP	152	struct cn_callback_data *d;
acd042bb EP	153
05e52dd7 PR	154	err = -ENOMEM;
	155	__new_cbq = kzalloc(sizeof(struct cn_callback_entry), GFP_ATOMIC);
	156	if (__new_cbq) {
	157	d = &__new_cbq->data;
acd042bb EP	158	d->callback_priv = msg;
	159	d->callback = __cbq->data.callback;
	160	d->ddata = data;
	161	d->destruct_data = destruct_data;
05e52dd7	162	d->free = __new_cbq;
acd042bb	163
05e52dd7	164	INIT_WORK(&__new_cbq->work,
a240d9f1	165	&cn_queue_wrapper);
05e52dd7	166
a240d9f1	167	if (queue_work(dev->cbdev->cn_queue,
05e52dd7	168	&__new_cbq->work))
acd042bb EP	169	err = 0;
acd042bb EP	170	else {
05e52dd7	171	kfree(__new_cbq);
acd042bb EP	172	err = -EINVAL;
acd042bb EP	173	}
05e52dd7	174	}
7672d0b5 EP	175	}
	176	break;
	177	}
	178	}
	179	spin_unlock_bh(&dev->cbdev->queue_lock);
	180
acd042bb	181	return err;
7672d0b5 EP	182	}
7672d0b5 EP	183
7672d0b5 EP	184	/*
	185	* Main netlink receiving function.
	186	*
00f5e06c	187	* It checks skb, netlink header and msg sizes, and calls callback helper.
7672d0b5 EP	188	*/
	189	static void cn_rx_skb(struct sk_buff *__skb)
	190	{
00f5e06c	191	struct cn_msg *msg;
7672d0b5	192	struct nlmsghdr *nlh;
7672d0b5 EP	193	int err;
	194	struct sk_buff *skb;
	195
	196	skb = skb_get(__skb);
	197
	198	if (skb->len >= NLMSG_SPACE(0)) {
b529ccf2	199	nlh = nlmsg_hdr(skb);
7672d0b5 EP	200
	201	if (nlh->nlmsg_len < sizeof(struct cn_msg) \|\|
	202	skb->len < nlh->nlmsg_len \|\|
	203	nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
	204	kfree_skb(skb);
6cf92e98	205	return;
7672d0b5 EP	206	}
7672d0b5 EP	207
00f5e06c LZ	208	msg = NLMSG_DATA(nlh);
00f5e06c LZ	209	err = cn_call_callback(msg, (void ()(void ))kfree_skb, skb);
7672d0b5 EP	210	if (err < 0)
	211	kfree_skb(skb);
	212	}
7672d0b5 EP	213	}
7672d0b5 EP	214
7672d0b5 EP	215	/*
	216	* Notification routing.
	217	*
	218	* Gets id and checks if there are notification request for it's idx
	219	* and val. If there are such requests notify the listeners with the
	220	* given notify event.
	221	*
	222	*/
	223	static void cn_notify(struct cb_id *id, u32 notify_event)
	224	{
	225	struct cn_ctl_entry *ent;
	226
8ed965d6	227	mutex_lock(&notify_lock);
7672d0b5 EP	228	list_for_each_entry(ent, &notify_list, notify_entry) {
	229	int i;
	230	struct cn_notify_req *req;
	231	struct cn_ctl_msg *ctl = ent->msg;
	232	int idx_found, val_found;
	233
	234	idx_found = val_found = 0;
	235
	236	req = (struct cn_notify_req *)ctl->data;
	237	for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
	238	if (id->idx >= req->first &&
	239	id->idx < req->first + req->range) {
	240	idx_found = 1;
	241	break;
	242	}
	243	}
	244
	245	for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
	246	if (id->val >= req->first &&
	247	id->val < req->first + req->range) {
	248	val_found = 1;
	249	break;
	250	}
	251	}
	252
	253	if (idx_found && val_found) {
	254	struct cn_msg m = { .ack = notify_event, };
	255
	256	memcpy(&m.id, id, sizeof(m.id));
	257	cn_netlink_send(&m, ctl->group, GFP_KERNEL);
	258	}
	259	}
8ed965d6	260	mutex_unlock(&notify_lock);
7672d0b5 EP	261	}
	262
	263	/*
	264	* Callback add routing - adds callback with given ID and name.
	265	* If there is registered callback with the same ID it will not be added.
	266	*
	267	* May sleep.
	268	*/
	269	int cn_add_callback(struct cb_id id, char name, void (callback)(void ))
	270	{
	271	int err;
	272	struct cn_dev *dev = &cdev;
7672d0b5	273
d6cc7f1a EP	274	if (!cn_already_initialized)
	275	return -EAGAIN;
	276
acd042bb EP	277	err = cn_queue_add_callback(dev->cbdev, name, id, callback);
acd042bb EP	278	if (err)
7672d0b5	279	return err;
7672d0b5 EP	280
	281	cn_notify(id, 0);
	282
	283	return 0;
	284	}
deb0e9b2	285	EXPORT_SYMBOL_GPL(cn_add_callback);
7672d0b5 EP	286
	287	/*
	288	* Callback remove routing - removes callback
	289	* with given ID.
	290	* If there is no registered callback with given
	291	* ID nothing happens.
	292	*
	293	* May sleep while waiting for reference counter to become zero.
	294	*/
	295	void cn_del_callback(struct cb_id *id)
	296	{
	297	struct cn_dev *dev = &cdev;
	298
	299	cn_queue_del_callback(dev->cbdev, id);
	300	cn_notify(id, 1);
	301	}
deb0e9b2	302	EXPORT_SYMBOL_GPL(cn_del_callback);
7672d0b5 EP	303
	304	/*
	305	* Checks two connector's control messages to be the same.
	306	* Returns 1 if they are the same or if the first one is corrupted.
	307	*/
	308	static int cn_ctl_msg_equals(struct cn_ctl_msg m1, struct cn_ctl_msg m2)
	309	{
	310	int i;
	311	struct cn_notify_req req1, req2;
	312
	313	if (m1->idx_notify_num != m2->idx_notify_num)
	314	return 0;
	315
	316	if (m1->val_notify_num != m2->val_notify_num)
	317	return 0;
	318
	319	if (m1->len != m2->len)
	320	return 0;
	321
	322	if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
	323	m1->len)
	324	return 1;
	325
	326	req1 = (struct cn_notify_req *)m1->data;
	327	req2 = (struct cn_notify_req *)m2->data;
	328
	329	for (i = 0; i < m1->idx_notify_num; ++i) {
	330	if (req1->first != req2->first \|\| req1->range != req2->range)
	331	return 0;
	332	req1++;
	333	req2++;
	334	}
	335
	336	for (i = 0; i < m1->val_notify_num; ++i) {
	337	if (req1->first != req2->first \|\| req1->range != req2->range)
	338	return 0;
	339	req1++;
	340	req2++;
	341	}
	342
	343	return 1;
	344	}
	345
	346	/*
	347	* Main connector device's callback.
	348	*
	349	* Used for notification of a request's processing.
	350	*/
	351	static void cn_callback(void *data)
	352	{
	353	struct cn_msg *msg = data;
	354	struct cn_ctl_msg *ctl;
	355	struct cn_ctl_entry *ent;
	356	u32 size;
	357
	358	if (msg->len < sizeof(*ctl))
	359	return;
	360
	361	ctl = (struct cn_ctl_msg *)msg->data;
	362
	363	size = (sizeof(*ctl) + ((ctl->idx_notify_num +
	364	ctl->val_notify_num) *
	365	sizeof(struct cn_notify_req)));
	366
367	if (msg->len != size)
368	return;
369
370	if (ctl->len + sizeof(*ctl) != msg->len)
371	return;
372
373	/*
374	* Remove notification.
375	*/
376	if (ctl->group == 0) {
377	struct cn_ctl_entry *n;
378
8ed965d6	379	mutex_lock(&notify_lock);
7672d0b5 EP	380	list_for_each_entry_safe(ent, n, &notify_list, notify_entry) {
	381	if (cn_ctl_msg_equals(ent->msg, ctl)) {
	382	list_del(&ent->notify_entry);
	383	kfree(ent);
	384	}
	385	}
8ed965d6	386	mutex_unlock(&notify_lock);
7672d0b5 EP	387
	388	return;
	389	}
	390
	391	size += sizeof(*ent);
	392
	393	ent = kzalloc(size, GFP_KERNEL);
	394	if (!ent)
	395	return;
	396
	397	ent->msg = (struct cn_ctl_msg *)(ent + 1);
	398
	399	memcpy(ent->msg, ctl, size - sizeof(*ent));
	400
8ed965d6	401	mutex_lock(&notify_lock);
7672d0b5	402	list_add(&ent->notify_entry, &notify_list);
8ed965d6	403	mutex_unlock(&notify_lock);
7672d0b5 EP	404	}
7672d0b5 EP	405
d6cc7f1a	406	static int __devinit cn_init(void)
7672d0b5 EP	407	{
	408	struct cn_dev *dev = &cdev;
	409	int err;
	410
cd40b7d3	411	dev->input = cn_rx_skb;
7672d0b5 EP	412	dev->id.idx = cn_idx;
	413	dev->id.val = cn_val;
	414
b4b51029	415	dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR,
7672d0b5	416	CN_NETLINK_USERS + 0xf,
af65bdfc	417	dev->input, NULL, THIS_MODULE);
7672d0b5 EP	418	if (!dev->nls)
	419	return -EIO;
	420
	421	dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
	422	if (!dev->cbdev) {
b7c6ba6e	423	netlink_kernel_release(dev->nls);
7672d0b5 EP	424	return -EINVAL;
7672d0b5 EP	425	}
d6cc7f1a EP	426
d6cc7f1a EP	427	cn_already_initialized = 1;
7672d0b5 EP	428
	429	err = cn_add_callback(&dev->id, "connector", &cn_callback);
	430	if (err) {
d6cc7f1a	431	cn_already_initialized = 0;
7672d0b5	432	cn_queue_free_dev(dev->cbdev);
b7c6ba6e	433	netlink_kernel_release(dev->nls);
7672d0b5 EP	434	return -EINVAL;
	435	}
	436
7672d0b5 EP	437	return 0;
	438	}
	439
d6cc7f1a	440	static void __devexit cn_fini(void)
7672d0b5 EP	441	{
	442	struct cn_dev *dev = &cdev;
	443
	444	cn_already_initialized = 0;
	445
	446	cn_del_callback(&dev->id);
	447	cn_queue_free_dev(dev->cbdev);
b7c6ba6e	448	netlink_kernel_release(dev->nls);
7672d0b5 EP	449	}
7672d0b5 EP	450
d6cc7f1a	451	subsys_initcall(cn_init);
7672d0b5	452	module_exit(cn_fini);