[deliverable/linux.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 <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 DECLARE_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,
		    unsigned int __nocast 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;
	}

	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;

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

	return 0;

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;

	down(&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);
		}
	}
	up(&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;

		down(&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);
			}
		}
		up(&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));

	down(&notify_lock);
	list_add(&ent->notify_entry, &notify_list);
	up(&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>
	29
	30	#include <net/sock.h>
	31
	32	MODULE_LICENSE("GPL");
	33	MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
	34	MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
	35
	36	static u32 cn_idx = CN_IDX_CONNECTOR;
	37	static u32 cn_val = CN_VAL_CONNECTOR;
	38
	39	module_param(cn_idx, uint, 0);
	40	module_param(cn_val, uint, 0);
	41	MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
	42	MODULE_PARM_DESC(cn_val, "Connector's main device val.");
	43
	44	static DECLARE_MUTEX(notify_lock);
	45	static LIST_HEAD(notify_list);
	46
	47	static struct cn_dev cdev;
	48
	49	int cn_already_initialized = 0;
	50
	51	/*
	52	* msg->seq and msg->ack are used to determine message genealogy.
	53	* When someone sends message it puts there locally unique sequence
	54	* and random acknowledge numbers. Sequence number may be copied into
	55	* nlmsghdr->nlmsg_seq too.
	56	*
	57	* Sequence number is incremented with each message to be sent.
	58	*
	59	* If we expect reply to our message then the sequence number in
	60	* received message MUST be the same as in original message, and
	61	* acknowledge number MUST be the same + 1.
	62	*
	63	* If we receive a message and its sequence number is not equal to the
	64	* one we are expecting then it is a new message.
65	*
66	* If we receive a message and its sequence number is the same as one
67	* we are expecting but it's acknowledgement number is not equal to
68	* the acknowledgement number in the original message + 1, then it is
69	* a new message.
70	*
71	*/
17b69885 RD	72	int cn_netlink_send(struct cn_msg *msg, u32 __group,
17b69885 RD	73	unsigned int __nocast 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
	101	size = NLMSG_SPACE(sizeof(*msg) + msg->len);
	102
	103	skb = alloc_skb(size, gfp_mask);
	104	if (!skb)
	105	return -ENOMEM;
	106
	107	nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
	108
	109	data = NLMSG_DATA(nlh);
	110
	111	memcpy(data, msg, sizeof(*data) + msg->len);
	112
	113	NETLINK_CB(skb).dst_group = group;
	114
	115	netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
	116
	117	return 0;
	118
	119	nlmsg_failure:
	120	kfree_skb(skb);
	121	return -EINVAL;
	122	}
	123
	124	/*
	125	* Callback helper - queues work and setup destructor for given data.
	126	*/
	127	static int cn_call_callback(struct cn_msg msg, void (destruct_data)(void ), void data)
	128	{
	129	struct cn_callback_entry *__cbq;
	130	struct cn_dev *dev = &cdev;
acd042bb	131	int err = -ENODEV;
7672d0b5 EP	132
	133	spin_lock_bh(&dev->cbdev->queue_lock);
	134	list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
acd042bb	135	if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
7672d0b5	136	if (likely(!test_bit(0, &__cbq->work.pending) &&
acd042bb EP	137	__cbq->data.ddata == NULL)) {
acd042bb EP	138	__cbq->data.callback_priv = msg;
7672d0b5	139
acd042bb EP	140	__cbq->data.ddata = data;
acd042bb EP	141	__cbq->data.destruct_data = destruct_data;
7672d0b5 EP	142
	143	if (queue_work(dev->cbdev->cn_queue,
	144	&__cbq->work))
acd042bb	145	err = 0;
7672d0b5	146	} else {
acd042bb EP	147	struct work_struct *w;
	148	struct cn_callback_data *d;
	149
	150	w = kzalloc(sizeof(w) + sizeof(d), GFP_ATOMIC);
	151	if (w) {
	152	d = (struct cn_callback_data *)(w+1);
	153
	154	d->callback_priv = msg;
	155	d->callback = __cbq->data.callback;
	156	d->ddata = data;
	157	d->destruct_data = destruct_data;
	158	d->free = w;
	159
	160	INIT_LIST_HEAD(&w->entry);
	161	w->pending = 0;
	162	w->func = &cn_queue_wrapper;
	163	w->data = d;
	164	init_timer(&w->timer);
	165
	166	if (queue_work(dev->cbdev->cn_queue, w))
	167	err = 0;
	168	else {
	169	kfree(w);
	170	err = -EINVAL;
	171	}
	172	} else
	173	err = -ENOMEM;
7672d0b5 EP	174	}
	175	break;
	176	}
	177	}
	178	spin_unlock_bh(&dev->cbdev->queue_lock);
	179
acd042bb	180	return err;
7672d0b5 EP	181	}
	182
	183	/*
	184	* Skb receive helper - checks skb and msg size and calls callback
	185	* helper.
	186	*/
	187	static int __cn_rx_skb(struct sk_buff skb, struct nlmsghdr nlh)
	188	{
	189	u32 pid, uid, seq, group;
	190	struct cn_msg *msg;
	191
	192	pid = NETLINK_CREDS(skb)->pid;
	193	uid = NETLINK_CREDS(skb)->uid;
	194	seq = nlh->nlmsg_seq;
	195	group = NETLINK_CB((skb)).dst_group;
	196	msg = NLMSG_DATA(nlh);
	197
	198	return cn_call_callback(msg, (void ()(void ))kfree_skb, skb);
	199	}
	200
	201	/*
	202	* Main netlink receiving function.
	203	*
	204	* It checks skb and netlink header sizes and calls the skb receive
	205	* helper with a shared skb.
	206	*/
	207	static void cn_rx_skb(struct sk_buff *__skb)
	208	{
	209	struct nlmsghdr *nlh;
	210	u32 len;
	211	int err;
	212	struct sk_buff *skb;
	213
	214	skb = skb_get(__skb);
	215
	216	if (skb->len >= NLMSG_SPACE(0)) {
	217	nlh = (struct nlmsghdr *)skb->data;
	218
	219	if (nlh->nlmsg_len < sizeof(struct cn_msg) \|\|
	220	skb->len < nlh->nlmsg_len \|\|
	221	nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
	222	kfree_skb(skb);
	223	goto out;
	224	}
	225
	226	len = NLMSG_ALIGN(nlh->nlmsg_len);
	227	if (len > skb->len)
	228	len = skb->len;
	229
	230	err = __cn_rx_skb(skb, nlh);
	231	if (err < 0)
	232	kfree_skb(skb);
	233	}
	234
	235	out:
	236	kfree_skb(__skb);
	237	}
	238
	239	/*
	240	* Netlink socket input callback - dequeues the skbs and calls the
	241	* main netlink receiving function.
	242	*/
	243	static void cn_input(struct sock *sk, int len)
	244	{
245	struct sk_buff *skb;
246
247	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL)
248	cn_rx_skb(skb);
249	}
250
251	/*
252	* Notification routing.
253	*
254	* Gets id and checks if there are notification request for it's idx
255	* and val. If there are such requests notify the listeners with the
256	* given notify event.
257	*
258	*/
259	static void cn_notify(struct cb_id *id, u32 notify_event)
260	{
261	struct cn_ctl_entry *ent;
262
263	down(&notify_lock);
264	list_for_each_entry(ent, &notify_list, notify_entry) {
265	int i;
266	struct cn_notify_req *req;
267	struct cn_ctl_msg *ctl = ent->msg;
268	int idx_found, val_found;
269
270	idx_found = val_found = 0;
271
272	req = (struct cn_notify_req *)ctl->data;
273	for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
274	if (id->idx >= req->first &&
275	id->idx < req->first + req->range) {
276	idx_found = 1;
277	break;
278	}
279	}
280
281	for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
282	if (id->val >= req->first &&
283	id->val < req->first + req->range) {
284	val_found = 1;
285	break;
286	}
287	}
288
289	if (idx_found && val_found) {
290	struct cn_msg m = { .ack = notify_event, };
291
292	memcpy(&m.id, id, sizeof(m.id));
293	cn_netlink_send(&m, ctl->group, GFP_KERNEL);
294	}
295	}
296	up(&notify_lock);
297	}
298
299	/*
300	* Callback add routing - adds callback with given ID and name.
301	* If there is registered callback with the same ID it will not be added.
302	*
303	* May sleep.
304	*/
305	int cn_add_callback(struct cb_id id, char name, void (callback)(void ))
306	{
307	int err;
308	struct cn_dev *dev = &cdev;
7672d0b5	309
acd042bb EP	310	err = cn_queue_add_callback(dev->cbdev, name, id, callback);
acd042bb EP	311	if (err)
7672d0b5	312	return err;
7672d0b5 EP	313
	314	cn_notify(id, 0);
	315
	316	return 0;
	317	}
	318
	319	/*
	320	* Callback remove routing - removes callback
	321	* with given ID.
	322	* If there is no registered callback with given
	323	* ID nothing happens.
	324	*
	325	* May sleep while waiting for reference counter to become zero.
	326	*/
	327	void cn_del_callback(struct cb_id *id)
	328	{
	329	struct cn_dev *dev = &cdev;
	330
	331	cn_queue_del_callback(dev->cbdev, id);
	332	cn_notify(id, 1);
	333	}
	334
	335	/*
	336	* Checks two connector's control messages to be the same.
	337	* Returns 1 if they are the same or if the first one is corrupted.
	338	*/
	339	static int cn_ctl_msg_equals(struct cn_ctl_msg m1, struct cn_ctl_msg m2)
	340	{
	341	int i;
	342	struct cn_notify_req req1, req2;
	343
	344	if (m1->idx_notify_num != m2->idx_notify_num)
	345	return 0;
	346
	347	if (m1->val_notify_num != m2->val_notify_num)
	348	return 0;
	349
	350	if (m1->len != m2->len)
	351	return 0;
	352
	353	if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
	354	m1->len)
	355	return 1;
	356
	357	req1 = (struct cn_notify_req *)m1->data;
	358	req2 = (struct cn_notify_req *)m2->data;
	359
	360	for (i = 0; i < m1->idx_notify_num; ++i) {
	361	if (req1->first != req2->first \|\| req1->range != req2->range)
	362	return 0;
	363	req1++;
	364	req2++;
	365	}
	366
	367	for (i = 0; i < m1->val_notify_num; ++i) {
	368	if (req1->first != req2->first \|\| req1->range != req2->range)
	369	return 0;
	370	req1++;
	371	req2++;
	372	}
	373
	374	return 1;
	375	}
	376
377	/*
378	* Main connector device's callback.
379	*
380	* Used for notification of a request's processing.
381	*/
382	static void cn_callback(void *data)
383	{
384	struct cn_msg *msg = data;
385	struct cn_ctl_msg *ctl;
386	struct cn_ctl_entry *ent;
387	u32 size;
388
389	if (msg->len < sizeof(*ctl))
390	return;
391
392	ctl = (struct cn_ctl_msg *)msg->data;
393
394	size = (sizeof(*ctl) + ((ctl->idx_notify_num +
395	ctl->val_notify_num) *
396	sizeof(struct cn_notify_req)));
397
398	if (msg->len != size)
399	return;
400
401	if (ctl->len + sizeof(*ctl) != msg->len)
402	return;
403
404	/*
405	* Remove notification.
406	*/
407	if (ctl->group == 0) {
408	struct cn_ctl_entry *n;
409
410	down(&notify_lock);
411	list_for_each_entry_safe(ent, n, &notify_list, notify_entry) {
412	if (cn_ctl_msg_equals(ent->msg, ctl)) {
413	list_del(&ent->notify_entry);
414	kfree(ent);
415	}
416	}
417	up(&notify_lock);
418
419	return;
420	}
421
422	size += sizeof(*ent);
423
424	ent = kzalloc(size, GFP_KERNEL);
425	if (!ent)
426	return;
427
428	ent->msg = (struct cn_ctl_msg *)(ent + 1);
429
430	memcpy(ent->msg, ctl, size - sizeof(*ent));
431
432	down(&notify_lock);
433	list_add(&ent->notify_entry, &notify_list);
434	up(&notify_lock);
435	}
436
437	static int __init cn_init(void)
438	{
439	struct cn_dev *dev = &cdev;
440	int err;
441
442	dev->input = cn_input;
443	dev->id.idx = cn_idx;
444	dev->id.val = cn_val;
445
446	dev->nls = netlink_kernel_create(NETLINK_CONNECTOR,
447	CN_NETLINK_USERS + 0xf,
448	dev->input, THIS_MODULE);
449	if (!dev->nls)
450	return -EIO;
451
452	dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
453	if (!dev->cbdev) {
454	if (dev->nls->sk_socket)
455	sock_release(dev->nls->sk_socket);
456	return -EINVAL;
457	}
458
459	err = cn_add_callback(&dev->id, "connector", &cn_callback);
460	if (err) {
461	cn_queue_free_dev(dev->cbdev);
462	if (dev->nls->sk_socket)
463	sock_release(dev->nls->sk_socket);
464	return -EINVAL;
465	}
466
467	cn_already_initialized = 1;
468
469	return 0;
470	}
471
472	static void __exit cn_fini(void)
473	{
474	struct cn_dev *dev = &cdev;
475
476	cn_already_initialized = 0;
477
478	cn_del_callback(&dev->id);
479	cn_queue_free_dev(dev->cbdev);
480	if (dev->nls->sk_socket)
481	sock_release(dev->nls->sk_socket);
482	}
483
484	module_init(cn_init);
485	module_exit(cn_fini);
486
487	EXPORT_SYMBOL_GPL(cn_add_callback);
488	EXPORT_SYMBOL_GPL(cn_del_callback);
489	EXPORT_SYMBOL_GPL(cn_netlink_send);