Kernel connector - userspace <-> kernelspace "linker".

Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

[-- Attachment #1.1: Type: text/plain, Size: 1118 bytes --]

Hmm, do not know how to describe... 
Kind of mega-picture can be found at 
http://tservice.net.ru/~s0mbre/?section=gallery&item=connector_design

This driver adds possibility to connect anything with anything using
netlink based network.
One must register callback and identificator. When driver receives
special netlink message with appropriate identificator, appropriate
callback will be called.
I think that the code better explains what I'm trying to say.

cn_queue.[ch] - main queue processing routings.
connector.[ch] - interface to the external modules.
ucon.c - userspace daemon. It is broken a bit, but the main idea is 
	very clear.
cn_test.c - module to test new connector.
Makefile - it will link all above cruft.

Origianlly this was written for SuperIO and w1 subsystems to connect 
them to userspace, but actually it can be used outside those projects.
Greg KH recommended to send it to linux-kernl@ mail list, but I personally 
no not like that too "floodfil" list.

Please review and comment.

-- 
	Evgeniy Polyakov

Crash is better than data corruption. -- Art Grabowski

[-- Attachment #1.2: cn_queue.c --]
[-- Type: text/x-csrc, Size: 5361 bytes --]

/*
 * 	cn_queue.c
 * 
 * 2004 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/workqueue.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/suspend.h>

#include "cn_queue.h"

static void cn_queue_wrapper(void *data)
{
	struct cn_callback_entry *cbq = (struct cn_callback_entry *)data;

	atomic_inc(&cbq->cb->refcnt);
	cbq->cb->callback(cbq->cb->priv);
	atomic_dec(&cbq->cb->refcnt);

	cbq->destruct_data(cbq->ddata);
}

static struct cn_callback_entry *cn_queue_alloc_callback_entry(struct
							       cn_callback *cb)
{
	struct cn_callback_entry *cbq;

	cbq = kmalloc(sizeof(*cbq), GFP_KERNEL);
	if (!cbq) {
		printk(KERN_ERR "Failed to create new callback queue.\n");
		return NULL;
	}

	memset(cbq, 0, sizeof(*cbq));

	cbq->cb = cb;

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

	return cbq;
}

static void cn_queue_free_callback(struct cn_callback_entry *cbq)
{
	cancel_delayed_work(&cbq->work);

	while (atomic_read(&cbq->cb->refcnt)) {
		printk(KERN_INFO "Waiting %s to became free: refcnt=%d.\n",
		       cbq->pdev->name, atomic_read(&cbq->cb->refcnt));
		set_current_state(TASK_INTERRUPTIBLE);
		schedule_timeout(HZ);

		if (current->flags & PF_FREEZE)
			refrigerator(PF_FREEZE);

		if (signal_pending(current))
			flush_signals(current);
	}

	kfree(cbq);
}

int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
{
	return ((i1->idx == i2->idx) && (i1->val == i2->val));
}

int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb)
{
	struct cn_callback_entry *cbq, *n, *__cbq;
	int found = 0;

	cbq = cn_queue_alloc_callback_entry(cb);
	if (!cbq)
		return -ENOMEM;

	atomic_inc(&dev->refcnt);
	cbq->pdev = dev;

	spin_lock(&dev->queue_lock);
	list_for_each_entry_safe(__cbq, n, &dev->queue_list, callback_entry) {
		if (cn_cb_equal(&__cbq->cb->id, &cb->id)) {
			found = 1;
			break;
		}
	}
	if (!found) {
		atomic_set(&cbq->cb->refcnt, 1);
		list_add_tail(&cbq->callback_entry, &dev->queue_list);
	}
	spin_unlock(&dev->queue_lock);

	if (found) {
		atomic_dec(&dev->refcnt);
		atomic_set(&cbq->cb->refcnt, 0);
		cn_queue_free_callback(cbq);
		return -EINVAL;
	}

	cbq->nls = dev->nls;
	cbq->seq = 0;
	cbq->group = ++dev->netlink_groups;

	return 0;
}

void cn_queue_del_callback(struct cn_queue_dev *dev, struct cn_callback *cb)
{
	struct cn_callback_entry *cbq = NULL, *n;
	int found = 0;

	spin_lock(&dev->queue_lock);
	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
		if (cn_cb_equal(&cbq->cb->id, &cb->id)) {
			list_del(&cbq->callback_entry);
			found = 1;
			break;
		}
	}
	spin_unlock(&dev->queue_lock);

	if (found) {
		atomic_dec(&cbq->cb->refcnt);
		cn_queue_free_callback(cbq);
		atomic_dec(&dev->refcnt);
	}
}

struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls)
{
	struct cn_queue_dev *dev;

	dev = kmalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev) {
		printk(KERN_ERR "%s: Failed to allocte new struct cn_queue_dev.\n",
		       name);
		return NULL;
	}

	memset(dev, 0, sizeof(*dev));

	snprintf(dev->name, sizeof(dev->name), "%s", name);

	atomic_set(&dev->refcnt, 0);
	INIT_LIST_HEAD(&dev->queue_list);
	spin_lock_init(&dev->queue_lock);

	dev->nls = nls;
	dev->netlink_groups = 0;

	dev->cn_queue = create_workqueue(dev->name);
	if (!dev->cn_queue) {
		printk(KERN_ERR "Failed to create %s queue.\n", dev->name);
		kfree(dev);
		return NULL;
	}

	return dev;
}

void cn_queue_free_dev(struct cn_queue_dev *dev)
{
	struct cn_callback_entry *cbq, *n;

	flush_workqueue(dev->cn_queue);
	destroy_workqueue(dev->cn_queue);

	spin_lock(&dev->queue_lock);
	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
		list_del(&cbq->callback_entry);
		atomic_dec(&cbq->cb->refcnt);
	}
	spin_unlock(&dev->queue_lock);

	while (atomic_read(&dev->refcnt)) {
		printk(KERN_INFO "Waiting %s to became free: refcnt=%d.\n",
		       dev->name, atomic_read(&dev->refcnt));
		set_current_state(TASK_INTERRUPTIBLE);
		schedule_timeout(HZ);

		if (current->flags & PF_FREEZE)
			refrigerator(PF_FREEZE);

		if (signal_pending(current))
			flush_signals(current);
	}

	memset(dev, 0, sizeof(*dev));
	kfree(dev);
	dev = NULL;
}

EXPORT_SYMBOL(cn_queue_add_callback);
EXPORT_SYMBOL(cn_queue_del_callback);
EXPORT_SYMBOL(cn_queue_alloc_dev);
EXPORT_SYMBOL(cn_queue_free_dev);

[-- Attachment #1.3: cn_queue.h --]
[-- Type: text/x-chdr, Size: 2144 bytes --]

/*
 * 	cn_queue.h
 * 
 * 2004 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
 */

#ifndef __CN_QUEUE_H
#define __CN_QUEUE_H

#include <asm/types.h>

struct cb_id
{
	__u32			idx;
	__u32			val;
};

#ifdef __KERNEL__

#include <asm/atomic.h>

#include <linux/list.h>
#include <linux/workqueue.h>

#define CN_CBQ_NAMELEN		32

struct cn_queue_dev
{
	atomic_t		refcnt;
	unsigned char		name[CN_CBQ_NAMELEN];

	struct workqueue_struct	*cn_queue;
	
	struct list_head 	queue_list;
	spinlock_t 		queue_lock;

	int			netlink_groups;
	struct sock		*nls;
};

struct cn_callback
{
	unsigned char		name[CN_CBQ_NAMELEN];
	
	struct cb_id		id;
	void			(* callback)(void *);
	void			*priv;
	
	atomic_t		refcnt;
};

struct cn_callback_entry
{
	struct list_head	callback_entry;
	struct cn_callback	*cb;
	struct work_struct	work;
	struct cn_queue_dev	*pdev;
	
	void			(* destruct_data)(void *);
	void			*ddata;

	int			seq, group;
	struct sock		*nls;
};

int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb);
void cn_queue_del_callback(struct cn_queue_dev *dev, struct cn_callback *cb);

struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *);
void cn_queue_free_dev(struct cn_queue_dev *dev);

int cn_cb_equal(struct cb_id *, struct cb_id *);

#endif /* __KERNEL__ */
#endif /* __CN_QUEUE_H */

[-- Attachment #1.4: cn_test.c --]
[-- Type: text/x-csrc, Size: 1744 bytes --]

/*
 * 	cn_test.c
 * 
 * 2004 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/moduleparam.h>

#include "connector.h"

static struct cb_id cn_test_id = { 0x123, 0x456 };
static char cn_test_name[] = "cn_test";

void cn_test_callback(void *data)
{
	struct cn_msg *msg = (struct cn_msg *)data;

	printk("%s: idx=%x, val=%x, len=%d.\n",
	       __func__, msg->id.idx, msg->id.val, msg->len);
}

static int cn_test_init(void)
{
	int err;

	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
	if (err)
		return err;
	cn_test_id.val++;
	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
	if (err) {
		cn_del_callback(&cn_test_id);
		return err;
	}

	return 0;
}

static void cn_test_fini(void)
{
	cn_del_callback(&cn_test_id);
	cn_test_id.val--;
	cn_del_callback(&cn_test_id);
}

module_init(cn_test_init);
module_exit(cn_test_fini);

[-- Attachment #1.5: connector.c --]
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/*
 * 	connector.c
 * 
 * 2004 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 <net/sock.h>

#include "../connector/connector.h"
#include "../connector/cn_queue.h"

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

static int unit = NETLINK_NFLOG;
module_param(unit, int, 0);

struct cn_dev cdev;

/*
 * 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 sequence number in received message MUST be the same as in original message,
 * and acknowledge number MUST be the same + 1.
 *
 * If we receive message and it's sequence number is not equal to one we are expecting, 
 * then it is new message.
 * If we receive message and it's sequence number is the same as one we are expecting,
 * but it's acknowledge is not equal acknowledge number in original message + 1,
 * then it is new message.
 *
 */
void cn_netlink_send(struct cn_msg *msg)
{
	struct cn_callback_entry *n, *__cbq;
	unsigned int size;
	struct sk_buff *skb;
	struct nlmsghdr *nlh;
	struct cn_msg *data;
	struct cn_dev *dev = &cdev;
	u32 groups = 0;
	int found = 0;

	spin_lock(&dev->cbdev->queue_lock);
	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
		if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
			found = 1;
			groups = __cbq->group;
		}
	}
	spin_unlock(&dev->cbdev->queue_lock);

	if (!found) {
		printk(KERN_ERR "Failed to find multicast netlink group for callback[0x%x.0x%x]. seq=%u\n",
		       msg->id.idx, msg->id.val, msg->seq);
		return;
	}

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

	skb = alloc_skb(size, GFP_ATOMIC);
	if (!skb) {
		printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", size);
		return;
	}

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

	data = (struct cn_msg *)NLMSG_DATA(nlh);

	memcpy(data, msg, sizeof(*data) + msg->len);
#if 0
	printk("%s: len=%u, seq=%u, ack=%u, group=%u.\n",
	       __func__, msg->len, msg->seq, msg->ack, groups);
#endif
	NETLINK_CB(skb).dst_groups = groups;
	netlink_broadcast(dev->nls, skb, 0, groups, GFP_ATOMIC);

	return;

      nlmsg_failure:
	printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack);
	kfree_skb(skb);
	return;
}

static int cn_call_callback(struct cn_msg *msg, void (*destruct_data) (void *), void *data)
{
	struct cn_callback_entry *n, *__cbq;
	struct cn_dev *dev = &cdev;
	int found = 0;

	spin_lock(&dev->cbdev->queue_lock);
	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
		if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
			__cbq->cb->priv = msg;

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

			queue_work(dev->cbdev->cn_queue, &__cbq->work);
			found = 1;
			break;
		}
	}
	spin_unlock(&dev->cbdev->queue_lock);

	return found;
}

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)).groups;
	msg = (struct cn_msg *)NLMSG_DATA(nlh);
#if 0
	printk(KERN_INFO "pid=%u, uid=%u, seq=%u, group=%u.\n",
	       pid, uid, seq, group);
#endif
	return cn_call_callback(msg, (void (*)(void *))kfree_skb, 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) {
		printk(KERN_ERR "Failed to reference an skb.\n");
		return;
	}
#if 0
	printk(KERN_INFO
	       "skb: len=%u, data_len=%u, truesize=%u, proto=%u, cloned=%d, shared=%d.\n",
	       skb->len, skb->data_len, skb->truesize, skb->protocol,
	       skb_cloned(skb), skb_shared(skb));
#endif
	while (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) {
			printk(KERN_INFO "nlmsg_len=%u, sizeof(*nlh)=%u\n",
			       nlh->nlmsg_len, sizeof(*nlh));
			break;
		}

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

		err = __cn_rx_skb(skb, nlh);
		if (err) {
			if (err < 0)
				netlink_ack(skb, nlh, -err);
			kfree_skb(skb);
			break;
		} else {
			if (nlh->nlmsg_flags & NLM_F_ACK)
				netlink_ack(skb, nlh, 0);
			kfree_skb(skb);
			break;
		}
		skb_pull(skb, len);
	}
}

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);
}

int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *))
{
	int err;
	struct cn_dev *dev = &cdev;
	struct cn_callback *cb;

	cb = kmalloc(sizeof(*cb), GFP_KERNEL);
	if (!cb) {
		printk(KERN_INFO "%s: Failed to allocate new struct cn_callback.\n",
		       dev->cbdev->name);
		return -ENOMEM;
	}

	memset(cb, 0, sizeof(*cb));

	snprintf(cb->name, sizeof(cb->name), "%s", name);

	memcpy(&cb->id, id, sizeof(cb->id));
	cb->callback = callback;

	atomic_set(&cb->refcnt, 0);

	err = cn_queue_add_callback(dev->cbdev, cb);
	if (err) {
		kfree(cb);
		return err;
	}

	return 0;
}

void cn_del_callback(struct cb_id *id)
{
	struct cn_dev *dev = &cdev;
	struct cn_callback_entry *n, *__cbq;

	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
		if (cn_cb_equal(&__cbq->cb->id, id)) {
			cn_queue_del_callback(dev->cbdev, __cbq->cb);
			break;
		}
	}
}

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

	dev->input = cn_input;

	dev->nls = netlink_kernel_create(unit, dev->input);
	if (!dev->nls) {
		printk(KERN_ERR "Failed to create new netlink socket(%u).\n",
		       unit);
		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;
	}

	return 0;
}

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

	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(cn_add_callback);
EXPORT_SYMBOL(cn_del_callback);
EXPORT_SYMBOL(cn_netlink_send);

[-- Attachment #1.6: connector.h --]
[-- Type: text/x-chdr, Size: 1523 bytes --]

/*
 * 	connector.h
 * 
 * 2004 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
 */

#ifndef __CONNECTOR_H
#define __CONNECTOR_H

#include "../connector/cn_queue.h"

#define CONNECTOR_MAX_MSG_SIZE 	1024

struct cn_msg
{
	struct cb_id 		id;

	__u32			seq;
	__u32			ack;

	__u32			len;		/* Length of the following data */
	__u8			data[0];
};

#ifdef __KERNEL__

#include <net/sock.h>

struct cn_dev
{
	u32			seq, groups;
	struct sock 		*nls;
	void 			(*input)(struct sock *sk, int len);

	struct cn_queue_dev	*cbdev;
};

int cn_add_callback(struct cb_id *, char *, void (* callback)(void *));
void cn_del_callback(struct cb_id *);
void cn_netlink_send(struct cn_msg *);

#endif /* __KERNEL__ */
#endif /* __CONNECTOR_H */

[-- Attachment #1.7: Makefile --]
[-- Type: text/x-makefile, Size: 364 bytes --]

obj-m		:= cn.o cn_test.o
cn-objs		:= cn_queue.o connector.o

#KDIR	:= /lib/modules/$(shell uname -r)/build
KDIR	:= /usr/local/src/linux-2.6/linux-2.6.6
PWD	:= $(shell pwd)

default:
	$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules

clean:
	rm -f *.o *.ko *.mod.* .*.cmd *~
	rm -rf .tmp_versions

ucon:	ucon.c connector.h
	gcc -W -Wall -O9 ucon.c -o ucon

[-- Attachment #1.8: ucon.c --]
[-- Type: text/x-csrc, Size: 4532 bytes --]

/*
 * 	ucon.c
 *
 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
 * 
 *
 * 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 <asm/types.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/poll.h>

#include <linux/netlink.h>
#include <linux/rtnetlink.h>

#include <arpa/inet.h>

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <time.h>

#include "connector.h"
#include "../soekris/sc_conn.h"

static int need_exit;
__u32 seq;

static int netlink_send(int s, char *data)
{
	struct nlmsghdr *nlh;
	unsigned int size;
	int err;
	char buf[128];
	struct cn_msg *m, *msg;
	struct sc_conn_data *cmd;

	size = NLMSG_SPACE(sizeof(struct cn_msg) + sizeof(struct sc_conn_data));

	nlh = (struct nlmsghdr *)buf;
	nlh->nlmsg_seq = seq++;
	nlh->nlmsg_pid = getpid();
	nlh->nlmsg_type = NLMSG_DONE;
	nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
	nlh->nlmsg_flags = 0;

	m = NLMSG_DATA(nlh);
	msg = (struct cn_msg *)data;
	cmd = (struct sc_conn_data *)(msg + 1);

	printf("%s: len=%u, seq=%u, ack=%u, "
	       "sname=%s, lname=%s, idx=0x%x, cmd=%02x [%02x.%02x.%02x].\n",
	       __func__,
	       msg->len, msg->seq, msg->ack,
	       cmd->sname,
	       cmd->lname, cmd->idx, cmd->cmd, cmd->p0, cmd->p1, cmd->p2);

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

	err = send(s, nlh, size, 0);
	if (err == -1)
		fprintf(stderr, "Failed to send: %s [%d].\n",
			strerror(errno), errno);

	return err;
}

int main(int argc, char *argv[])
{
	int s;
	char buf[1024];
	int len;
	struct nlmsghdr *reply;
	struct sockaddr_nl l_local;
	struct cn_msg *data;
	struct sc_conn_data *m;
	FILE *out;
	time_t tm;
	struct pollfd pfd;

	if (argc < 2)
		out = stdout;
	else {
		out = fopen(argv[1], "a+");
		if (!out) {
			fprintf(stderr, "Unable to open %s for writing: %s\n",
				argv[1], strerror(errno));
			out = stdout;
		}
	}

	memset(buf, 0, sizeof(buf));

	s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_NFLOG);
	if (s == -1) {
		perror("socket");
		return -1;
	}

	l_local.nl_family = AF_NETLINK;
	l_local.nl_groups = 1;
	l_local.nl_pid = getpid();

	if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) ==
	    -1) {
		perror("bind");
		close(s);
		return -1;
	}

	pfd.fd = s;

	while (!need_exit) {
		pfd.events = POLLIN;
		pfd.revents = 0;
		/*switch (poll(&pfd, 1, -1)) 
		   {
		   case 0:
		   need_exit = 1;
		   break;
		   case -1:
		   if (errno != EINTR) 
		   {
		   need_exit = 1;
		   break;
		   }
		   continue;
		   } */
		if (need_exit)
			break;

		data = (struct cn_msg *)buf;

		data->id.idx = 0xaabb;
		data->id.val = 0xccdd;
		data->seq = seq++;
		data->ack = (seq ^ 0x1234);
		data->len = sizeof(*m);

		m = (struct sc_conn_data *)(data + 1);
		memset(m, 0, sizeof(*m));

		m->cmd = SC_CMD_LDEV_READ;
		m->idx = 0xff;
		sprintf(m->sname, "PC8736X");
		sprintf(m->lname, "GPIO");

		m->p0 = 21;

		len = netlink_send(s, buf);

		len = recv(s, buf, sizeof(buf), 0);
		if (len == -1) {
			perror("recv buf");
			close(s);
			return -1;
		}
		reply = (struct nlmsghdr *)buf;

		switch (reply->nlmsg_type) {
		case NLMSG_ERROR:
			fprintf(out, "Error message received.\n");
			fflush(out);
			break;
		case NLMSG_DONE:
			data = (struct cn_msg *)NLMSG_DATA(reply);
			m = (struct sc_conn_data *)(data + 1);

			time(&tm);
			fprintf(out,
				"%.24s : [%x.%x] [seq=%u, ack=%u], sname=%s, lname=%s, idx=%u, cmd=%#02x [%#02x.%#02x.%#02x]\n",
				ctime(&tm), data->id.idx, data->id.val,
				data->seq, data->ack, m->sname, m->lname,
				m->idx, m->cmd, m->p0, m->p1, m->p2);
			fflush(out);
			break;
		default:
			break;
		}

		sleep(1);
	}

	close(s);
	return 0;
}

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

Re: Kernel connector - userspace <-> kernelspace "linker".

[jamal]

On Thu, 2004-09-16 at 06:51, Evgeniy Polyakov wrote:
> Hmm, do not know how to describe... 
> Kind of mega-picture can be found at 
> http://tservice.net.ru/~s0mbre/?section=gallery&item=connector_design
> 
> This driver adds possibility to connect anything with anything using
> netlink based network.
> One must register callback and identificator. When driver receives
> special netlink message with appropriate identificator, appropriate
> callback will be called.
> I think that the code better explains what I'm trying to say.

I dont have time to evaluate the code right now - but will at the end of
day. Just trying to understand your concepts:

Essentially you are building a unified messaging for
userspace-userpace(i.e IPC), userspace-kernel, kernel-kernel with each
component residing in whatever spot (kernel or userland)having a unique
name and Id. Is this correct?
Clearly there could be name/Id conflicts etc. Are you addressing those? 
Any event and filtering capability already in or planned? Example event
I want to be notified when module with name "sean paul" comes online and
filter will be "it has to have ID in the range of 0x200-0x400".

I am still trying to wakeup but it does sound like a good idea to have a
generic messaging subsystem.

cheers,
jamal 

Re: Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

Sorry for thread destruction, but I have not received you mail, 
but see it in archive. I do beleive it is due to permanent glitch of 
2ka.mipt.ru SMTP server.

> I dont have time to evaluate the code right now - but will at the end of
> day. Just trying to understand your concepts:
>
> Essentially you are building a unified messaging for
> userspace-userpace(i.e IPC), userspace-kernel, kernel-kernel with each
> component residing in whatever spot (kernel or userland)having a unique
> name and Id. Is this correct?

Actually name and ID should be transformed to ID0 and ID1(they are callled
idx and val and are u32 values, since I strongly object against any ASCII 
based identificators( sigh, I am cunning - superio has such ids)).
Since userspace can not register callback function, then it is not quite 
fair to call it generic, but the idea is right.

> Clearly there could be name/Id conflicts etc. Are you addressing those? 

Hmm, u32+u32 - I do not beleive that it can conflict, but if they do, then
first registered with given idx+val will pay the pipper and call the tune.
Second call with the same parameters for register_callback() fill fail.

> Any event and filtering capability already in or planned? Example event
> I want to be notified when module with name "sean paul" comes online and
> filter will be "it has to have ID in the range of 0x200-0x400".

Such information does exist in connector driver and it _can_ be easily 
obtained. I will call it feature request that fits the design 
and will implement this today/tomorrow. :)

> I am still trying to wakeup but it does sound like a good idea to have a
> generic messaging subsystem.

Good afternoon :).

cheers,
jamal 

	Evgeniy Polyakov

Only failure makes us experts. -- Theo de Raadt

Re: Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

On Thu, Sep 16, 2004 at 08:03:04PM +0400, Evgeniy Polyakov wrote:
> Sorry for thread destruction, but I have not received you mail, 
> but see it in archive. I do beleive it is due to permanent glitch of 
> 2ka.mipt.ru SMTP server.
> 
> > I dont have time to evaluate the code right now - but will at the end of
> > day. Just trying to understand your concepts:
> >
> > Essentially you are building a unified messaging for
> > userspace-userpace(i.e IPC), userspace-kernel, kernel-kernel with each
> > component residing in whatever spot (kernel or userland)having a unique
> > name and Id. Is this correct?
> 
> Actually name and ID should be transformed to ID0 and ID1(they are callled
> idx and val and are u32 values, since I strongly object against any ASCII 
> based identificators( sigh, I am cunning - superio has such ids)).
> Since userspace can not register callback function, then it is not quite 
> fair to call it generic, but the idea is right.
> 
> > Clearly there could be name/Id conflicts etc. Are you addressing those? 
> 
> Hmm, u32+u32 - I do not beleive that it can conflict, but if they do, then
> first registered with given idx+val will pay the pipper and call the tune.
> Second call with the same parameters for register_callback() fill fail.
> 
> > Any event and filtering capability already in or planned? Example event
> > I want to be notified when module with name "sean paul" comes online and
> > filter will be "it has to have ID in the range of 0x200-0x400".
> 
> Such information does exist in connector driver and it _can_ be easily 
> obtained. I will call it feature request that fits the design 
> and will implement this today/tomorrow. :)
> 
> > I am still trying to wakeup but it does sound like a good idea to have a
> > generic messaging subsystem.
> 
> Good afternoon :).

kind of dmesg:

Notify group 1 for idx: 291-300
Notify group 1 for val: 1110-1119 1130-1139
Request was sent. Group=0x1.
+ + <6>Notifying group 1 with event 0 about 123.456.
+ + <6>Notifying group 1 with event 0 about 123.457.
+ + <6>Notifying group 1 with event 1 about 123.457.
+ + <6>Notifying group 1 with event 1 about 123.456.

0 - device added
1 - removed


Kind of patch...

* looking for johnpol@2ka.mipt.ru-2004/connector--main--0--patch-10 to compare with
* comparing to johnpol@2ka.mipt.ru-2004/connector--main--0--patch-10
M  cn_test.c
M  connector.c
M  connector.h
M  ucon.c

* modified files

--- orig/cn_test.c
+++ mod/cn_test.c
@@ -22,11 +22,13 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/skbuff.h>
 
 #include "connector.h"
 
 static struct cb_id cn_test_id = { 0x123, 0x456 };
 static char cn_test_name[] = "cn_test";
+static struct sock *nls;
 
 void cn_test_callback(void *data)
 {
@@ -36,21 +38,112 @@
 	       __func__, msg->id.idx, msg->id.val, msg->len);
 }
 
+static int cn_test_want_notify(void)
+{
+	struct cn_ctl_msg *ctl;
+	struct cn_notify_req *req;
+	struct cn_msg *msg = NULL;
+	int size, size0;
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+	u32 group = 1;
+
+	size0 = sizeof(*msg) + sizeof(*ctl) + 3*sizeof(*req);
+	
+	size = NLMSG_SPACE(size0);
+
+	skb = alloc_skb(size, GFP_ATOMIC);
+	if (!skb) {
+		printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", size);
+
+		return -ENOMEM;
+	}
+
+	nlh = NLMSG_PUT(skb, 0, 0x123, NLMSG_DONE, size - sizeof(*nlh));
+
+	msg = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	memset(msg, 0, size0);
+
+	msg->id.idx 	= -1;
+	msg->id.val 	= -1;
+	msg->seq 	= 0x123;
+	msg->ack 	= 0x345;
+	msg->len 	= size0 - sizeof(*msg);
+
+	ctl = (struct cn_ctl_msg *)(msg + 1);
+
+	ctl->idx_notify_num 	= 1;
+	ctl->val_notify_num 	= 2;
+	ctl->group		= group;
+
+	req = (struct cn_notify_req *)(ctl + 1);
+
+	/*
+	 * Idx.
+	 */
+	req->first = cn_test_id.idx;
+	req->range = 10;
+
+	/*
+	 * Val 0.
+	 */
+	req++;
+	req->first = cn_test_id.val;
+	req->range = 10;
+	
+	/*
+	 * Val 1.
+	 */
+	req++;
+	req->first = cn_test_id.val + 20;
+	req->range = 10;
+	
+	NETLINK_CB(skb).dst_groups = ctl->group;
+	//netlink_broadcast(nls, skb, 0, ctl->group, GFP_ATOMIC);
+	netlink_unicast(nls, skb, 0, 0);
+
+	printk(KERN_INFO "Request was sent. Group=0x%x.\n", group);
+		
+	return 0;
+
+nlmsg_failure:
+	printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack);
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
 static int cn_test_init(void)
 {
 	int err;
+	
+	nls = netlink_kernel_create(NETLINK_NFLOG, NULL);
+	if (!nls) {
+		printk(KERN_ERR "Failed to create new netlink socket(%u).\n", NETLINK_NFLOG);
+		return -EIO;
+	}
+
+	err = cn_test_want_notify();
+	if (err)
+		goto err_out;
 
 	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
 	if (err)
-		return err;
+		goto err_out;
 	cn_test_id.val++;
 	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
 	if (err) {
 		cn_del_callback(&cn_test_id);
-		return err;
+		goto err_out;
 	}
 
 	return 0;
+
+err_out:
+	if (nls->sk_socket)
+		sock_release(nls->sk_socket);
+
+	return err;
 }
 
 static void cn_test_fini(void)
@@ -58,6 +151,8 @@
 	cn_del_callback(&cn_test_id);
 	cn_test_id.val--;
 	cn_del_callback(&cn_test_id);
+	if (nls->sk_socket)
+		sock_release(nls->sk_socket);
 }
 
 module_init(cn_test_init);


--- orig/connector.c
+++ mod/connector.c
@@ -36,9 +36,17 @@
 MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
 
 static int unit = NETLINK_NFLOG;
+static u32 cn_idx = -1;
+static u32 cn_val = -1;
+
 module_param(unit, int, 0);
+module_param(cn_idx, uint, 0);
+module_param(cn_val, uint, 0);
+
+spinlock_t notify_lock = SPIN_LOCK_UNLOCKED;
+static LIST_HEAD(notify_list);
 
-struct cn_dev cdev;
+static struct cn_dev cdev;
 
 /*
  * msg->seq and msg->ack are used to determine message genealogy.
@@ -59,7 +67,7 @@
  * then it is new message.
  *
  */
-void cn_netlink_send(struct cn_msg *msg)
+void cn_netlink_send(struct cn_msg *msg, u32 __groups)
 {
 	struct cn_callback_entry *n, *__cbq;
 	unsigned int size;
@@ -70,20 +78,25 @@
 	u32 groups = 0;
 	int found = 0;
 
-	spin_lock(&dev->cbdev->queue_lock);
-	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
-		if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
-			found = 1;
-			groups = __cbq->group;
+	if (!__groups)
+	{
+		spin_lock(&dev->cbdev->queue_lock);
+		list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
+			if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
+				found = 1;
+				groups = __cbq->group;
+			}
 		}
-	}
-	spin_unlock(&dev->cbdev->queue_lock);
+		spin_unlock(&dev->cbdev->queue_lock);
 
-	if (!found) {
-		printk(KERN_ERR "Failed to find multicast netlink group for callback[0x%x.0x%x]. seq=%u\n",
-		       msg->id.idx, msg->id.val, msg->seq);
-		return;
+		if (!found) {
+			printk(KERN_ERR "Failed to find multicast netlink group for callback[0x%x.0x%x]. seq=%u\n",
+			       msg->id.idx, msg->id.val, msg->seq);
+			return;
+		}
 	}
+	else
+		groups = __groups;
 
 	size = NLMSG_SPACE(sizeof(*msg) + msg->len);
 
@@ -147,6 +160,15 @@
 	seq = nlh->nlmsg_seq;
 	group = NETLINK_CB((skb)).groups;
 	msg = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	if (msg->len != nlh->nlmsg_len - sizeof(*msg) - sizeof(*nlh))
+	{
+		printk(KERN_ERR "skb does not have enough length: requested msg->len=%u[%u], nlh->nlmsg_len=%u[%u], skb->len=%u[must be %u].\n", 
+				msg->len, NLMSG_SPACE(msg->len), 
+				nlh->nlmsg_len, nlh->nlmsg_len - sizeof(*nlh),
+				skb->len, msg->len + sizeof(*msg));
+		return -EINVAL;
+	}
 #if 0
 	printk(KERN_INFO "pid=%u, uid=%u, seq=%u, group=%u.\n",
 	       pid, uid, seq, group);
@@ -188,7 +210,7 @@
 
 		err = __cn_rx_skb(skb, nlh);
 		if (err) {
-			if (err < 0)
+			if (err < 0 && (nlh->nlmsg_flags & NLM_F_ACK))
 				netlink_ack(skb, nlh, -err);
 			kfree_skb(skb);
 			break;
@@ -210,6 +232,59 @@
 		cn_rx_skb(skb);
 }
 
+static void cn_notify(struct cb_id *id, u32 notify_event)
+{
+	struct cn_ctl_entry *ent;
+
+	spin_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 a, b;
+
+		a = b = 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)
+			{
+				printk("+ ");
+				a = 1;
+				break;
+			}
+		}
+		
+		for (i=0; i<ctl->val_notify_num; ++i, ++req)
+		{
+			if (id->val >= req->first && id->val < req->first + req->range)
+			{
+				printk("+ ");
+				b = 1;
+				break;
+			}
+		}
+
+		if (a && b)
+		{
+			struct cn_msg m;
+			
+			printk(KERN_INFO "Notifying group %x with event %u about %x.%x.\n", 
+					ctl->group, notify_event, 
+					id->idx, id->val);
+
+			memset(&m, 0, sizeof(m));
+			m.ack = notify_event;
+
+			memcpy(&m.id, id, sizeof(m.id));
+			cn_netlink_send(&m, ctl->group);
+		}
+	}
+	spin_unlock(&notify_lock);
+}
+
 int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *))
 {
 	int err;
@@ -237,6 +312,8 @@
 		kfree(cb);
 		return err;
 	}
+			
+	cn_notify(id, 0);
 
 	return 0;
 }
@@ -249,16 +326,85 @@
 	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
 		if (cn_cb_equal(&__cbq->cb->id, id)) {
 			cn_queue_del_callback(dev->cbdev, __cbq->cb);
+			cn_notify(id, 1);
 			break;
 		}
 	}
 }
 
+static void cn_callback(void * data)
+{
+	struct cn_msg *msg = (struct cn_msg *)data;
+	struct cn_ctl_msg *ctl;
+	struct cn_ctl_entry *ent;
+	u32 size;
+ 
+	if (msg->len < sizeof(*ctl))
+	{
+		printk(KERN_ERR "Wrong connector request size %u, must be >= %u.\n", 
+				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)
+	{
+		printk(KERN_ERR "Wrong connector request size %u, must be == %u.\n", 
+				msg->len, size);
+		return;
+	}
+
+	size += sizeof(*ent);
+
+	ent = kmalloc(size, GFP_ATOMIC);
+	if (!ent)
+	{
+		printk(KERN_ERR "Failed to allocate %d bytes for new notify entry.\n", size);
+		return;
+	}
+
+	memset(ent, 0, size);
+
+	ent->msg = (struct cn_ctl_msg *)(ent + 1);
+
+	memcpy(ent->msg, ctl, size - sizeof(*ent));
+
+	spin_lock(&notify_lock);
+	list_add(&ent->notify_entry, &notify_list);
+	spin_unlock(&notify_lock);
+
+	{
+		int i;
+		struct cn_notify_req *req;
+	
+		printk("Notify group %x for idx: ", ctl->group);
+
+		req = (struct cn_notify_req *)ctl->data;
+		for (i=0; i<ctl->idx_notify_num; ++i, ++req)
+		{
+			printk("%u-%u ", req->first, req->first+req->range-1);
+		}
+		
+		printk("\nNotify group %x for val: ", ctl->group);
+
+		for (i=0; i<ctl->val_notify_num; ++i, ++req)
+		{
+			printk("%u-%u ", req->first, req->first+req->range-1);
+		}
+		printk("\n");
+	}
+}
+
 static int cn_init(void)
 {
 	struct cn_dev *dev = &cdev;
 
 	dev->input = cn_input;
+	dev->id.idx = cn_idx;
+	dev->id.val = cn_val;
 
 	dev->nls = netlink_kernel_create(unit, dev->input);
 	if (!dev->nls) {
@@ -274,13 +420,14 @@
 		return -EINVAL;
 	}
 
-	return 0;
+	return cn_add_callback(&dev->id, "connector", &cn_callback);
 }
 
 static void cn_fini(void)
 {
 	struct cn_dev *dev = &cdev;
 
+	cn_del_callback(&dev->id);
 	cn_queue_free_dev(dev->cbdev);
 	if (dev->nls->sk_socket)
 		sock_release(dev->nls->sk_socket);


--- orig/connector.h
+++ mod/connector.h
@@ -37,12 +37,34 @@
 	__u8			data[0];
 };
 
+struct cn_notify_req
+{
+	__u32			first;
+	__u32			range;
+};
+
+struct cn_ctl_msg
+{
+	__u32			idx_notify_num;
+	__u32			val_notify_num;
+	__u32			group;
+	__u8			data[0];
+};
+
 #ifdef __KERNEL__
 
 #include <net/sock.h>
 
+struct cn_ctl_entry
+{
+	struct list_head	notify_entry;
+	struct cn_ctl_msg	*msg;
+};
+
 struct cn_dev
 {
+	struct cb_id 		id;
+
 	u32			seq, groups;
 	struct sock 		*nls;
 	void 			(*input)(struct sock *sk, int len);
@@ -52,7 +74,7 @@
 
 int cn_add_callback(struct cb_id *, char *, void (* callback)(void *));
 void cn_del_callback(struct cb_id *);
-void cn_netlink_send(struct cn_msg *);
+void cn_netlink_send(struct cn_msg *, u32);
 
 #endif /* __KERNEL__ */
 #endif /* __CONNECTOR_H */


--- orig/ucon.c
+++ mod/ucon.c
@@ -118,8 +118,7 @@
 	l_local.nl_groups = 1;
 	l_local.nl_pid = getpid();
 
-	if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) ==
-	    -1) {
+	if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) == -1) {
 		perror("bind");
 		close(s);
 		return -1;




> 
> cheers,
> jamal 
> 
> 	Evgeniy Polyakov
> 
> Only failure makes us experts. -- Theo de Raadt

-- 
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
--
	Evgeniy Polyakov ( s0mbre )

Crash is better than data corruption. -- Artur Grabowski

Re: Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

[-- Attachment #1.1: Type: text/plain, Size: 1993 bytes --]

On Thu, 2004-09-16 at 16:09, jamal wrote:
> On Thu, 2004-09-16 at 06:51, Evgeniy Polyakov wrote:
> > Hmm, do not know how to describe... 
> > Kind of mega-picture can be found at 
> > http://tservice.net.ru/~s0mbre/?section=gallery&item=connector_design
> > 
> > This driver adds possibility to connect anything with anything using
> > netlink based network.
> > One must register callback and identificator. When driver receives
> > special netlink message with appropriate identificator, appropriate
> > callback will be called.
> > I think that the code better explains what I'm trying to say.
> 
> I dont have time to evaluate the code right now - but will at the end of
> day. Just trying to understand your concepts:
> 
> Essentially you are building a unified messaging for
> userspace-userpace(i.e IPC), userspace-kernel, kernel-kernel with each
> component residing in whatever spot (kernel or userland)having a unique
> name and Id. Is this correct?
> Clearly there could be name/Id conflicts etc. Are you addressing those? 
> Any event and filtering capability already in or planned? Example event
> I want to be notified when module with name "sean paul" comes online and
> filter will be "it has to have ID in the range of 0x200-0x400".
> 
> I am still trying to wakeup but it does sound like a good idea to have a
> generic messaging subsystem.

Attached patch cleans it up a bit and adds notify removal mechanism.
BTW, patch for cn_test.c test module is quite ugly, but it is only for
test. Real users can use cn_netlink_send().

It looks like noone objects, so I will create a patch and send it to
GregKH :) 
I know at least 2 potential users - w1 and pending superio( actually it
requires only connector to be included). I'm quite sure after I will
write bits of documentation for this cruft it will take broader usage.

Thank you.

> cheers,
> jamal 
-- 
	Evgeniy Polyakov

Crash is better than data corruption. -- Art Grabowski

[-- Attachment #1.2: connector.diff --]
[-- Type: text/x-patch, Size: 12503 bytes --]

* looking for johnpol@2ka.mipt.ru-2004/connector--main--0--patch-10 to compare with
* comparing to johnpol@2ka.mipt.ru-2004/connector--main--0--patch-10
M  cn_test.c
M  connector.c
M  connector.h
M  Makefile
M  ucon.c

* modified files

--- orig/Makefile
+++ mod/Makefile
@@ -2,7 +2,7 @@
 cn-objs		:= cn_queue.o connector.o
 
 #KDIR	:= /lib/modules/$(shell uname -r)/build
-KDIR	:= /usr/local/src/linux-2.6/linux-2.6.6
+KDIR	:= /usr/local/src/linux-2.6/linux-2.6
 PWD	:= $(shell pwd)
 
 default:


--- orig/cn_test.c
+++ mod/cn_test.c
@@ -22,11 +22,13 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/skbuff.h>
 
 #include "connector.h"
 
 static struct cb_id cn_test_id = { 0x123, 0x456 };
 static char cn_test_name[] = "cn_test";
+static struct sock *nls;
 
 void cn_test_callback(void *data)
 {
@@ -36,21 +38,112 @@
 	       __func__, msg->id.idx, msg->id.val, msg->len);
 }
 
+static int cn_test_want_notify(void)
+{
+	struct cn_ctl_msg *ctl;
+	struct cn_notify_req *req;
+	struct cn_msg *msg = NULL;
+	int size, size0;
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+	u32 group = 1;
+
+	size0 = sizeof(*msg) + sizeof(*ctl) + 3*sizeof(*req);
+	
+	size = NLMSG_SPACE(size0);
+
+	skb = alloc_skb(size, GFP_ATOMIC);
+	if (!skb) {
+		printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", size);
+
+		return -ENOMEM;
+	}
+
+	nlh = NLMSG_PUT(skb, 0, 0x123, NLMSG_DONE, size - sizeof(*nlh));
+
+	msg = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	memset(msg, 0, size0);
+
+	msg->id.idx 	= -1;
+	msg->id.val 	= -1;
+	msg->seq 	= 0x123;
+	msg->ack 	= 0x345;
+	msg->len 	= size0 - sizeof(*msg);
+
+	ctl = (struct cn_ctl_msg *)(msg + 1);
+
+	ctl->idx_notify_num 	= 1;
+	ctl->val_notify_num 	= 2;
+	ctl->group		= group;
+
+	req = (struct cn_notify_req *)(ctl + 1);
+
+	/*
+	 * Idx.
+	 */
+	req->first = cn_test_id.idx;
+	req->range = 10;
+
+	/*
+	 * Val 0.
+	 */
+	req++;
+	req->first = cn_test_id.val;
+	req->range = 10;
+	
+	/*
+	 * Val 1.
+	 */
+	req++;
+	req->first = cn_test_id.val + 20;
+	req->range = 10;
+	
+	NETLINK_CB(skb).dst_groups = ctl->group;
+	//netlink_broadcast(nls, skb, 0, ctl->group, GFP_ATOMIC);
+	netlink_unicast(nls, skb, 0, 0);
+
+	printk(KERN_INFO "Request was sent. Group=0x%x.\n", group);
+		
+	return 0;
+
+nlmsg_failure:
+	printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack);
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
 static int cn_test_init(void)
 {
 	int err;
+	
+	nls = netlink_kernel_create(NETLINK_NFLOG, NULL);
+	if (!nls) {
+		printk(KERN_ERR "Failed to create new netlink socket(%u).\n", NETLINK_NFLOG);
+		return -EIO;
+	}
+
+	err = cn_test_want_notify();
+	if (err)
+		goto err_out;
 
 	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
 	if (err)
-		return err;
+		goto err_out;
 	cn_test_id.val++;
 	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
 	if (err) {
 		cn_del_callback(&cn_test_id);
-		return err;
+		goto err_out;
 	}
 
 	return 0;
+
+err_out:
+	if (nls->sk_socket)
+		sock_release(nls->sk_socket);
+
+	return err;
 }
 
 static void cn_test_fini(void)
@@ -58,6 +151,8 @@
 	cn_del_callback(&cn_test_id);
 	cn_test_id.val--;
 	cn_del_callback(&cn_test_id);
+	if (nls->sk_socket)
+		sock_release(nls->sk_socket);
 }
 
 module_init(cn_test_init);


--- orig/connector.c
+++ mod/connector.c
@@ -36,9 +36,17 @@
 MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
 
 static int unit = NETLINK_NFLOG;
+static u32 cn_idx = -1;
+static u32 cn_val = -1;
+
 module_param(unit, int, 0);
+module_param(cn_idx, uint, 0);
+module_param(cn_val, uint, 0);
+
+spinlock_t notify_lock = SPIN_LOCK_UNLOCKED;
+static LIST_HEAD(notify_list);
 
-struct cn_dev cdev;
+static struct cn_dev cdev;
 
 /*
  * msg->seq and msg->ack are used to determine message genealogy.
@@ -59,7 +67,7 @@
  * then it is new message.
  *
  */
-void cn_netlink_send(struct cn_msg *msg)
+void cn_netlink_send(struct cn_msg *msg, u32 __groups)
 {
 	struct cn_callback_entry *n, *__cbq;
 	unsigned int size;
@@ -70,20 +78,25 @@
 	u32 groups = 0;
 	int found = 0;
 
-	spin_lock(&dev->cbdev->queue_lock);
-	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
-		if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
-			found = 1;
-			groups = __cbq->group;
+	if (!__groups)
+	{
+		spin_lock(&dev->cbdev->queue_lock);
+		list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
+			if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
+				found = 1;
+				groups = __cbq->group;
+			}
 		}
-	}
-	spin_unlock(&dev->cbdev->queue_lock);
+		spin_unlock(&dev->cbdev->queue_lock);
 
-	if (!found) {
-		printk(KERN_ERR "Failed to find multicast netlink group for callback[0x%x.0x%x]. seq=%u\n",
-		       msg->id.idx, msg->id.val, msg->seq);
-		return;
+		if (!found) {
+			printk(KERN_ERR "Failed to find multicast netlink group for callback[0x%x.0x%x]. seq=%u\n",
+			       msg->id.idx, msg->id.val, msg->seq);
+			return;
+		}
 	}
+	else
+		groups = __groups;
 
 	size = NLMSG_SPACE(sizeof(*msg) + msg->len);
 
@@ -147,6 +160,15 @@
 	seq = nlh->nlmsg_seq;
 	group = NETLINK_CB((skb)).groups;
 	msg = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	if (msg->len != nlh->nlmsg_len - sizeof(*msg) - sizeof(*nlh))
+	{
+		printk(KERN_ERR "skb does not have enough length: requested msg->len=%u[%u], nlh->nlmsg_len=%u[%u], skb->len=%u[must be %u].\n", 
+				msg->len, NLMSG_SPACE(msg->len), 
+				nlh->nlmsg_len, nlh->nlmsg_len - sizeof(*nlh),
+				skb->len, msg->len + sizeof(*msg));
+		return -EINVAL;
+	}
 #if 0
 	printk(KERN_INFO "pid=%u, uid=%u, seq=%u, group=%u.\n",
 	       pid, uid, seq, group);
@@ -188,7 +210,7 @@
 
 		err = __cn_rx_skb(skb, nlh);
 		if (err) {
-			if (err < 0)
+			if (err < 0 && (nlh->nlmsg_flags & NLM_F_ACK))
 				netlink_ack(skb, nlh, -err);
 			kfree_skb(skb);
 			break;
@@ -210,6 +232,59 @@
 		cn_rx_skb(skb);
 }
 
+static void cn_notify(struct cb_id *id, u32 notify_event)
+{
+	struct cn_ctl_entry *ent;
+
+	spin_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 a, b;
+
+		a = b = 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)
+			{
+				printk("+ ");
+				a = 1;
+				break;
+			}
+		}
+		
+		for (i=0; i<ctl->val_notify_num; ++i, ++req)
+		{
+			if (id->val >= req->first && id->val < req->first + req->range)
+			{
+				printk("+ ");
+				b = 1;
+				break;
+			}
+		}
+
+		if (a && b)
+		{
+			struct cn_msg m;
+			
+			printk(KERN_INFO "Notifying group %x with event %u about %x.%x.\n", 
+					ctl->group, notify_event, 
+					id->idx, id->val);
+
+			memset(&m, 0, sizeof(m));
+			m.ack = notify_event;
+
+			memcpy(&m.id, id, sizeof(m.id));
+			cn_netlink_send(&m, ctl->group);
+		}
+	}
+	spin_unlock(&notify_lock);
+}
+
 int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *))
 {
 	int err;
@@ -237,6 +312,8 @@
 		kfree(cb);
 		return err;
 	}
+			
+	cn_notify(id, 0);
 
 	return 0;
 }
@@ -249,16 +326,158 @@
 	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
 		if (cn_cb_equal(&__cbq->cb->id, id)) {
 			cn_queue_del_callback(dev->cbdev, __cbq->cb);
+			cn_notify(id, 1);
 			break;
 		}
 	}
 }
 
+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)
+	{
+		printk("Notify entry[idx_num=%x, val_num=%x, len=%u] contains garbage. Removing.\n", 
+				m1->idx_notify_num, m1->val_notify_num, 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 (memcmp(req1, req2, sizeof(*req1)))
+			return 0;
+
+		req1++;
+		req2++;
+	}
+
+	for (i=0; i<m1->val_notify_num; ++i)
+	{
+		if (memcmp(req1, req2, sizeof(*req1)))
+			return 0;
+
+		req1++;
+		req2++;
+	}
+
+	return 1;
+}
+
+static void cn_callback(void * data)
+{
+	struct cn_msg *msg = (struct cn_msg *)data;
+	struct cn_ctl_msg *ctl;
+	struct cn_ctl_entry *ent;
+	u32 size;
+ 
+	if (msg->len < sizeof(*ctl))
+	{
+		printk(KERN_ERR "Wrong connector request size %u, must be >= %u.\n", 
+				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)
+	{
+		printk(KERN_ERR "Wrong connector request size %u, must be == %u.\n", 
+				msg->len, size);
+		return;
+	}
+
+	if (ctl->len + sizeof(*ctl) != msg->len)
+	{
+		printk(KERN_ERR "Wrong message: msg->len=%u must be equal to inner_len=%u [+%u].\n", 
+				msg->len, ctl->len, sizeof(*ctl));
+		return;
+	}
+
+	/*
+	 * Remove notification.
+	 */
+	if (ctl->group == 0)
+	{
+		struct cn_ctl_entry *n;
+		
+		spin_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);
+			}
+		}
+		spin_unlock(&notify_lock);
+
+		return;
+	}
+
+	size += sizeof(*ent);
+
+	ent = kmalloc(size, GFP_ATOMIC);
+	if (!ent)
+	{
+		printk(KERN_ERR "Failed to allocate %d bytes for new notify entry.\n", size);
+		return;
+	}
+
+	memset(ent, 0, size);
+
+	ent->msg = (struct cn_ctl_msg *)(ent + 1);
+
+	memcpy(ent->msg, ctl, size - sizeof(*ent));
+
+	spin_lock(&notify_lock);
+	list_add(&ent->notify_entry, &notify_list);
+	spin_unlock(&notify_lock);
+
+	{
+		int i;
+		struct cn_notify_req *req;
+	
+		printk("Notify group %x for idx: ", ctl->group);
+
+		req = (struct cn_notify_req *)ctl->data;
+		for (i=0; i<ctl->idx_notify_num; ++i, ++req)
+		{
+			printk("%u-%u ", req->first, req->first+req->range-1);
+		}
+		
+		printk("\nNotify group %x for val: ", ctl->group);
+
+		for (i=0; i<ctl->val_notify_num; ++i, ++req)
+		{
+			printk("%u-%u ", req->first, req->first+req->range-1);
+		}
+		printk("\n");
+	}
+}
+
 static int cn_init(void)
 {
 	struct cn_dev *dev = &cdev;
 
 	dev->input = cn_input;
+	dev->id.idx = cn_idx;
+	dev->id.val = cn_val;
 
 	dev->nls = netlink_kernel_create(unit, dev->input);
 	if (!dev->nls) {
@@ -274,13 +493,14 @@
 		return -EINVAL;
 	}
 
-	return 0;
+	return cn_add_callback(&dev->id, "connector", &cn_callback);
 }
 
 static void cn_fini(void)
 {
 	struct cn_dev *dev = &cdev;
 
+	cn_del_callback(&dev->id);
 	cn_queue_free_dev(dev->cbdev);
 	if (dev->nls->sk_socket)
 		sock_release(dev->nls->sk_socket);


--- orig/connector.h
+++ mod/connector.h
@@ -37,12 +37,35 @@
 	__u8			data[0];
 };
 
+struct cn_notify_req
+{
+	__u32			first;
+	__u32			range;
+};
+
+struct cn_ctl_msg
+{
+	__u32			idx_notify_num;
+	__u32			val_notify_num;
+	__u32			group;
+	__u32			len;
+	__u8			data[0];
+};
+
 #ifdef __KERNEL__
 
 #include <net/sock.h>
 
+struct cn_ctl_entry
+{
+	struct list_head	notify_entry;
+	struct cn_ctl_msg	*msg;
+};
+
 struct cn_dev
 {
+	struct cb_id 		id;
+
 	u32			seq, groups;
 	struct sock 		*nls;
 	void 			(*input)(struct sock *sk, int len);
@@ -52,7 +75,7 @@
 
 int cn_add_callback(struct cb_id *, char *, void (* callback)(void *));
 void cn_del_callback(struct cb_id *);
-void cn_netlink_send(struct cn_msg *);
+void cn_netlink_send(struct cn_msg *, u32);
 
 #endif /* __KERNEL__ */
 #endif /* __CONNECTOR_H */


--- orig/ucon.c
+++ mod/ucon.c
@@ -118,8 +118,7 @@
 	l_local.nl_groups = 1;
 	l_local.nl_pid = getpid();
 
-	if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) ==
-	    -1) {
+	if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) == -1) {
 		perror("bind");
 		close(s);
 		return -1;




[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

Re: Kernel connector - userspace <-> kernelspace "linker".

[Alan Cox]

On Maw, 2004-09-21 at 13:46, Evgeniy Polyakov wrote:
> Connector driver adds possibility to connect various agents using
> netlink based network.
> One must register callback and identificator. When driver receives
> special netlink message with appropriate identificator, appropriate
> callback will be called.

Looks sane enough to me - and it seems to fit the mentality d-bus and
HAL want to have. 

Alan

ps: only trivial item (and really trivial) is that the printk messages
should be "waiting for %s".

Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

[-- Attachment #1: Type: text/plain, Size: 31448 bytes --]

Connector driver adds possibility to connect various agents using
netlink based network.
One must register callback and identificator. When driver receives
special netlink message with appropriate identificator, appropriate
callback will be called.

>From the userspace point of view it's quite straightforward:
socket();
bind();
send();
recv();

But if kernespace want to use full power of such connections, driver 
writer must create special sockets, must know about struct skbuff 
handling...
Following driver allows any kernelspace agents to use netlink based 
networking for inter-process communication in a significantly easier 
way:

register_callback(id, callback_function);
nc_connector_send();

where id is currently to 32bit values which can be considered as
name + id.

Current driver offers just transport layer but with fixed header.
Recommended protocol using such header is following:

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 sequence number in received 
message MUST be the same as in original message, and acknowledge 
number MUST be the same + 1.

If we receive message and it's sequence number is not equal to one 
we are expecting, then it is new message.
If we receive message and it's sequence number is the same as one we 
are expecting, but it's acknowledge is not equal acknowledge number 
in original message + 1, then it is new message.

Obviously, protocol header contains above id.

As a bonus, suggested by Jamal Hadi Salim in netdev@ maillist, 
connector driver allows event notification in the following form:
kernel driver or userspace process can ask connector to notify it 
when selected id's will be turned on or off(registered or unregistered 
it's callback). It is done by sending special command to connector 
driver(it also registers itself with id={-1, -1}).

Created schema contains large reserve for different future extensions.

Attached cn_test.c - it is a module that registers itself with connector 
cruft. It's sending function is quite ugly, but it was created only for 
testing. Real users do not need to use netlink sockets directly, but with 
help of cn_connector_send(). Please see connector.c itself
and it's cn_notify() call.
ucon.c - simple userspace utility that uses netlink sockets to read/write 
GPIO pin values from SuperIO subsystem in general and PC8746x chip/GPIO 
logical device in particular. SuperIO driver depends on connector and 
implements it's own protocol over connector's one. It will not be sent 
into linux-kernel@, but into LM Sensors <sensors@Stimpy.netroedge.com> 
mail list (actually it was sent several times during development cycle).

Please review, comment and apply to -mm for testing.

P.S. I'm not subscribed to linux-kernel@ mail list, so please CC: me in
your answers.

P.P.S. I believe this patch definitely can easily pass through anyone's coding 
style yuck-o-meter at one dash, even through Greg KH.

-- 
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>

--- linux-2.6/drivers/Makefile.orig	2004-09-12 01:14:07.000000000 +0400
+++ linux-2.6/drivers/Makefile	2004-09-11 22:49:32.000000000 +0400
@@ -43,6 +43,7 @@
 obj-$(CONFIG_I2O)		+= message/
 obj-$(CONFIG_I2C)		+= i2c/
 obj-$(CONFIG_W1)		+= w1/
+obj-$(CONFIG_CONNECTOR)		+= connector/
 obj-$(CONFIG_PHONE)		+= telephony/
 obj-$(CONFIG_MD)		+= md/
 obj-$(CONFIG_BT)		+= bluetooth/

--- linux-2.6/drivers/Kconfig	2004-09-21 13:56:46.000000000 +0400
+++ linux-2.6/drivers/Kconfig.orig	2004-09-21 13:55:18.000000000 +0400
@@ -44,6 +44,8 @@
 
 source "drivers/w1/Kconfig"
 
+source "drivers/connector/Kconfig"
+
 source "drivers/misc/Kconfig"
 
 source "drivers/media/Kconfig"

diff -Nru /tmp/empty/Kconfig linux-2.6/drivers/connector/Kconfig
--- /tmp/empty/Kconfig	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/Kconfig	2004-09-09 08:43:37.000000000 +0400
@@ -0,0 +1,13 @@
+menu "Connector - unified userspace <-> kernelspace linker"
+
+config CONNECTOR
+	tristate "Connector - unified userspace <-> kernelspace linker"
+	depends on NET
+	---help---
+	  This is unified userspace <-> kernelspace connector working on top
+	  of the netlink socket protocol.
+
+	  Connector support can also be built as a module.  If so, the module
+	  will be called connector.ko.
+
+endmenu
diff -Nru /tmp/empty/Makefile linux-2.6/drivers/connector/Makefile
--- /tmp/empty/Makefile	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/Makefile	2004-09-10 08:59:26.000000000 +0400
@@ -0,0 +1,2 @@
+obj-$(CONFIG_CONNECTOR)		+= cn.o
+cn-objs		:= cn_queue.o connector.o
diff -Nru /tmp/empty/cn_queue.c linux-2.6/drivers/connector/cn_queue.c
--- /tmp/empty/cn_queue.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/cn_queue.c	2004-09-21 13:38:57.000000000 +0400
@@ -0,0 +1,218 @@
+/*
+ * 	cn_queue.c
+ * 
+ * 2004 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/workqueue.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+#include <linux/suspend.h>
+
+#include "cn_queue.h"
+
+static void cn_queue_wrapper(void *data)
+{
+	struct cn_callback_entry *cbq = (struct cn_callback_entry *)data;
+
+	atomic_inc(&cbq->cb->refcnt);
+	cbq->cb->callback(cbq->cb->priv);
+	atomic_dec(&cbq->cb->refcnt);
+
+	cbq->destruct_data(cbq->ddata);
+}
+
+static struct cn_callback_entry *cn_queue_alloc_callback_entry(struct
+							       cn_callback *cb)
+{
+	struct cn_callback_entry *cbq;
+
+	cbq = kmalloc(sizeof(*cbq), GFP_KERNEL);
+	if (!cbq) {
+		printk(KERN_ERR "Failed to create new callback queue.\n");
+		return NULL;
+	}
+
+	memset(cbq, 0, sizeof(*cbq));
+
+	cbq->cb = cb;
+
+	INIT_WORK(&cbq->work, &cn_queue_wrapper, cbq);
+
+	return cbq;
+}
+
+static void cn_queue_free_callback(struct cn_callback_entry *cbq)
+{
+	cancel_delayed_work(&cbq->work);
+
+	while (atomic_read(&cbq->cb->refcnt)) {
+		printk(KERN_INFO "Waiting %s to became free: refcnt=%d.\n",
+		       cbq->pdev->name, atomic_read(&cbq->cb->refcnt));
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(HZ);
+
+		if (current->flags & PF_FREEZE)
+			refrigerator(PF_FREEZE);
+
+		if (signal_pending(current))
+			flush_signals(current);
+	}
+
+	kfree(cbq);
+}
+
+int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
+{
+	return ((i1->idx == i2->idx) && (i1->val == i2->val));
+}
+
+int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb)
+{
+	struct cn_callback_entry *cbq, *n, *__cbq;
+	int found = 0;
+
+	cbq = cn_queue_alloc_callback_entry(cb);
+	if (!cbq)
+		return -ENOMEM;
+
+	atomic_inc(&dev->refcnt);
+	cbq->pdev = dev;
+
+	spin_lock(&dev->queue_lock);
+	list_for_each_entry_safe(__cbq, n, &dev->queue_list, callback_entry) {
+		if (cn_cb_equal(&__cbq->cb->id, &cb->id)) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found) {
+		atomic_set(&cbq->cb->refcnt, 1);
+		list_add_tail(&cbq->callback_entry, &dev->queue_list);
+	}
+	spin_unlock(&dev->queue_lock);
+
+	if (found) {
+		atomic_dec(&dev->refcnt);
+		atomic_set(&cbq->cb->refcnt, 0);
+		cn_queue_free_callback(cbq);
+		return -EINVAL;
+	}
+
+	cbq->nls = dev->nls;
+	cbq->seq = 0;
+	cbq->group = ++dev->netlink_groups;
+
+	return 0;
+}
+
+void cn_queue_del_callback(struct cn_queue_dev *dev, struct cn_callback *cb)
+{
+	struct cn_callback_entry *cbq = NULL, *n;
+	int found = 0;
+
+	spin_lock(&dev->queue_lock);
+	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
+		if (cn_cb_equal(&cbq->cb->id, &cb->id)) {
+			list_del(&cbq->callback_entry);
+			found = 1;
+			break;
+		}
+	}
+	spin_unlock(&dev->queue_lock);
+
+	if (found) {
+		atomic_dec(&cbq->cb->refcnt);
+		cn_queue_free_callback(cbq);
+		atomic_dec(&dev->refcnt);
+	}
+}
+
+struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls)
+{
+	struct cn_queue_dev *dev;
+
+	dev = kmalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev) {
+		printk(KERN_ERR "%s: Failed to allocte new struct cn_queue_dev.\n",
+		       name);
+		return NULL;
+	}
+
+	memset(dev, 0, sizeof(*dev));
+
+	snprintf(dev->name, sizeof(dev->name), "%s", name);
+
+	atomic_set(&dev->refcnt, 0);
+	INIT_LIST_HEAD(&dev->queue_list);
+	spin_lock_init(&dev->queue_lock);
+
+	dev->nls = nls;
+	dev->netlink_groups = 0;
+
+	dev->cn_queue = create_workqueue(dev->name);
+	if (!dev->cn_queue) {
+		printk(KERN_ERR "Failed to create %s queue.\n", dev->name);
+		kfree(dev);
+		return NULL;
+	}
+
+	return dev;
+}
+
+void cn_queue_free_dev(struct cn_queue_dev *dev)
+{
+	struct cn_callback_entry *cbq, *n;
+
+	flush_workqueue(dev->cn_queue);
+	destroy_workqueue(dev->cn_queue);
+
+	spin_lock(&dev->queue_lock);
+	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
+		list_del(&cbq->callback_entry);
+		atomic_dec(&cbq->cb->refcnt);
+	}
+	spin_unlock(&dev->queue_lock);
+
+	while (atomic_read(&dev->refcnt)) {
+		printk(KERN_INFO "Waiting %s to became free: refcnt=%d.\n",
+		       dev->name, atomic_read(&dev->refcnt));
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(HZ);
+
+		if (current->flags & PF_FREEZE)
+			refrigerator(PF_FREEZE);
+
+		if (signal_pending(current))
+			flush_signals(current);
+	}
+
+	memset(dev, 0, sizeof(*dev));
+	kfree(dev);
+	dev = NULL;
+}
+
+EXPORT_SYMBOL(cn_queue_add_callback);
+EXPORT_SYMBOL(cn_queue_del_callback);
+EXPORT_SYMBOL(cn_queue_alloc_dev);
+EXPORT_SYMBOL(cn_queue_free_dev);
diff -Nru /tmp/empty/cn_queue.h linux-2.6/drivers/connector/cn_queue.h
--- /tmp/empty/cn_queue.h	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/cn_queue.h	2004-09-21 13:38:57.000000000 +0400
@@ -0,0 +1,90 @@
+/*
+ * 	cn_queue.h
+ * 
+ * 2004 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
+ */
+
+#ifndef __CN_QUEUE_H
+#define __CN_QUEUE_H
+
+#include <asm/types.h>
+
+struct cb_id
+{
+	__u32			idx;
+	__u32			val;
+};
+
+#ifdef __KERNEL__
+
+#include <asm/atomic.h>
+
+#include <linux/list.h>
+#include <linux/workqueue.h>
+
+#define CN_CBQ_NAMELEN		32
+
+struct cn_queue_dev
+{
+	atomic_t		refcnt;
+	unsigned char		name[CN_CBQ_NAMELEN];
+
+	struct workqueue_struct	*cn_queue;
+	
+	struct list_head 	queue_list;
+	spinlock_t 		queue_lock;
+
+	int			netlink_groups;
+	struct sock		*nls;
+};
+
+struct cn_callback
+{
+	unsigned char		name[CN_CBQ_NAMELEN];
+	
+	struct cb_id		id;
+	void			(* callback)(void *);
+	void			*priv;
+	
+	atomic_t		refcnt;
+};
+
+struct cn_callback_entry
+{
+	struct list_head	callback_entry;
+	struct cn_callback	*cb;
+	struct work_struct	work;
+	struct cn_queue_dev	*pdev;
+	
+	void			(* destruct_data)(void *);
+	void			*ddata;
+
+	int			seq, group;
+	struct sock		*nls;
+};
+
+int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb);
+void cn_queue_del_callback(struct cn_queue_dev *dev, struct cn_callback *cb);
+
+struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *);
+void cn_queue_free_dev(struct cn_queue_dev *dev);
+
+int cn_cb_equal(struct cb_id *, struct cb_id *);
+
+#endif /* __KERNEL__ */
+#endif /* __CN_QUEUE_H */
diff -Nru /tmp/empty/cn_test.c linux-2.6/drivers/connector/cn_test.c
--- /tmp/empty/cn_test.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/cn_test.c	2004-09-21 13:38:57.000000000 +0400
@@ -0,0 +1,160 @@
+/*
+ * 	cn_test.c
+ * 
+ * 2004 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/moduleparam.h>
+#include <linux/skbuff.h>
+
+#include "connector.h"
+
+static struct cb_id cn_test_id = { 0x123, 0x456 };
+static char cn_test_name[] = "cn_test";
+static struct sock *nls;
+
+void cn_test_callback(void *data)
+{
+	struct cn_msg *msg = (struct cn_msg *)data;
+
+	printk("%s: idx=%x, val=%x, len=%d.\n",
+	       __func__, msg->id.idx, msg->id.val, msg->len);
+}
+
+static int cn_test_want_notify(void)
+{
+	struct cn_ctl_msg *ctl;
+	struct cn_notify_req *req;
+	struct cn_msg *msg = NULL;
+	int size, size0;
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+	u32 group = 1;
+
+	size0 = sizeof(*msg) + sizeof(*ctl) + 3*sizeof(*req);
+	
+	size = NLMSG_SPACE(size0);
+
+	skb = alloc_skb(size, GFP_ATOMIC);
+	if (!skb) {
+		printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", size);
+
+		return -ENOMEM;
+	}
+
+	nlh = NLMSG_PUT(skb, 0, 0x123, NLMSG_DONE, size - sizeof(*nlh));
+
+	msg = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	memset(msg, 0, size0);
+
+	msg->id.idx 	= -1;
+	msg->id.val 	= -1;
+	msg->seq 	= 0x123;
+	msg->ack 	= 0x345;
+	msg->len 	= size0 - sizeof(*msg);
+
+	ctl = (struct cn_ctl_msg *)(msg + 1);
+
+	ctl->idx_notify_num 	= 1;
+	ctl->val_notify_num 	= 2;
+	ctl->group		= group;
+	ctl->len		= msg->len - sizeof(*ctl);
+
+	req = (struct cn_notify_req *)(ctl + 1);
+
+	/*
+	 * Idx.
+	 */
+	req->first = cn_test_id.idx;
+	req->range = 10;
+
+	/*
+	 * Val 0.
+	 */
+	req++;
+	req->first = cn_test_id.val;
+	req->range = 10;
+	
+	/*
+	 * Val 1.
+	 */
+	req++;
+	req->first = cn_test_id.val + 20;
+	req->range = 10;
+	
+	NETLINK_CB(skb).dst_groups = ctl->group;
+	//netlink_broadcast(nls, skb, 0, ctl->group, GFP_ATOMIC);
+	netlink_unicast(nls, skb, 0, 0);
+
+	printk(KERN_INFO "Request was sent. Group=0x%x.\n", group);
+		
+	return 0;
+
+nlmsg_failure:
+	printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack);
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+static int cn_test_init(void)
+{
+	int err;
+	
+	nls = netlink_kernel_create(NETLINK_NFLOG, NULL);
+	if (!nls) {
+		printk(KERN_ERR "Failed to create new netlink socket(%u).\n", NETLINK_NFLOG);
+		return -EIO;
+	}
+
+	err = cn_test_want_notify();
+	if (err)
+		goto err_out;
+
+	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
+	if (err)
+		goto err_out;
+	cn_test_id.val++;
+	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
+	if (err) {
+		cn_del_callback(&cn_test_id);
+		goto err_out;
+	}
+
+	return 0;
+
+err_out:
+	if (nls->sk_socket)
+		sock_release(nls->sk_socket);
+
+	return err;
+}
+
+static void cn_test_fini(void)
+{
+	cn_del_callback(&cn_test_id);
+	cn_test_id.val--;
+	cn_del_callback(&cn_test_id);
+	if (nls->sk_socket)
+		sock_release(nls->sk_socket);
+}
+
+module_init(cn_test_init);
+module_exit(cn_test_fini);
diff -Nru /tmp/empty/connector.c linux-2.6/drivers/connector/connector.c
--- /tmp/empty/connector.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/connector.c	2004-09-21 13:38:57.000000000 +0400
@@ -0,0 +1,496 @@
+/*
+ * 	connector.c
+ * 
+ * 2004 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 <net/sock.h>
+
+#include "../connector/connector.h"
+#include "../connector/cn_queue.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
+MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
+
+static int unit = NETLINK_NFLOG;
+static u32 cn_idx = -1;
+static u32 cn_val = -1;
+
+module_param(unit, int, 0);
+module_param(cn_idx, uint, 0);
+module_param(cn_val, uint, 0);
+
+spinlock_t notify_lock = SPIN_LOCK_UNLOCKED;
+static LIST_HEAD(notify_list);
+
+static struct cn_dev cdev;
+
+/*
+ * 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 sequence number in received message MUST be the same as in original message,
+ * and acknowledge number MUST be the same + 1.
+ *
+ * If we receive message and it's sequence number is not equal to one we are expecting, 
+ * then it is new message.
+ * If we receive message and it's sequence number is the same as one we are expecting,
+ * but it's acknowledge is not equal acknowledge number in original message + 1,
+ * then it is new message.
+ *
+ */
+void cn_netlink_send(struct cn_msg *msg, u32 __groups)
+{
+	struct cn_callback_entry *n, *__cbq;
+	unsigned int size;
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+	struct cn_msg *data;
+	struct cn_dev *dev = &cdev;
+	u32 groups = 0;
+	int found = 0;
+
+	if (!__groups)
+	{
+		spin_lock(&dev->cbdev->queue_lock);
+		list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
+			if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
+				found = 1;
+				groups = __cbq->group;
+			}
+		}
+		spin_unlock(&dev->cbdev->queue_lock);
+
+		if (!found) {
+			printk(KERN_ERR "Failed to find multicast netlink group for callback[0x%x.0x%x]. seq=%u\n",
+			       msg->id.idx, msg->id.val, msg->seq);
+			return;
+		}
+	}
+	else
+		groups = __groups;
+
+	size = NLMSG_SPACE(sizeof(*msg) + msg->len);
+
+	skb = alloc_skb(size, GFP_ATOMIC);
+	if (!skb) {
+		printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", size);
+		return;
+	}
+
+	nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
+
+	data = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	memcpy(data, msg, sizeof(*data) + msg->len);
+#if 0
+	printk("%s: len=%u, seq=%u, ack=%u, group=%u.\n",
+	       __func__, msg->len, msg->seq, msg->ack, groups);
+#endif
+	NETLINK_CB(skb).dst_groups = groups;
+	netlink_broadcast(dev->nls, skb, 0, groups, GFP_ATOMIC);
+
+	return;
+
+      nlmsg_failure:
+	printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack);
+	kfree_skb(skb);
+	return;
+}
+
+static int cn_call_callback(struct cn_msg *msg, void (*destruct_data) (void *), void *data)
+{
+	struct cn_callback_entry *n, *__cbq;
+	struct cn_dev *dev = &cdev;
+	int found = 0;
+
+	spin_lock(&dev->cbdev->queue_lock);
+	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
+		if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
+			__cbq->cb->priv = msg;
+
+			__cbq->ddata = data;
+			__cbq->destruct_data = destruct_data;
+
+			queue_work(dev->cbdev->cn_queue, &__cbq->work);
+			found = 1;
+			break;
+		}
+	}
+	spin_unlock(&dev->cbdev->queue_lock);
+
+	return found;
+}
+
+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)).groups;
+	msg = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	if (msg->len != nlh->nlmsg_len - sizeof(*msg) - sizeof(*nlh)) {
+		printk(KERN_ERR "skb does not have enough length: "
+				"requested msg->len=%u[%u], nlh->nlmsg_len=%u[%u], skb->len=%u[must be %u].\n", 
+				msg->len, NLMSG_SPACE(msg->len), 
+				nlh->nlmsg_len, nlh->nlmsg_len - sizeof(*nlh),
+				skb->len, msg->len + sizeof(*msg));
+		return -EINVAL;
+	}
+#if 0
+	printk(KERN_INFO "pid=%u, uid=%u, seq=%u, group=%u.\n",
+	       pid, uid, seq, group);
+#endif
+	return cn_call_callback(msg, (void (*)(void *))kfree_skb, 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) {
+		printk(KERN_ERR "Failed to reference an skb.\n");
+		return;
+	}
+#if 0
+	printk(KERN_INFO
+	       "skb: len=%u, data_len=%u, truesize=%u, proto=%u, cloned=%d, shared=%d.\n",
+	       skb->len, skb->data_len, skb->truesize, skb->protocol,
+	       skb_cloned(skb), skb_shared(skb));
+#endif
+	while (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) {
+			printk(KERN_INFO "nlmsg_len=%u, sizeof(*nlh)=%u\n",
+			       nlh->nlmsg_len, sizeof(*nlh));
+			break;
+		}
+
+		len = NLMSG_ALIGN(nlh->nlmsg_len);
+		if (len > skb->len)
+			len = skb->len;
+
+		err = __cn_rx_skb(skb, nlh);
+		if (err) {
+			if (err < 0 && (nlh->nlmsg_flags & NLM_F_ACK))
+				netlink_ack(skb, nlh, -err);
+			kfree_skb(skb);
+			break;
+		} else {
+			if (nlh->nlmsg_flags & NLM_F_ACK)
+				netlink_ack(skb, nlh, 0);
+			kfree_skb(skb);
+			break;
+		}
+		skb_pull(skb, len);
+	}
+}
+
+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);
+}
+
+static void cn_notify(struct cb_id *id, u32 notify_event)
+{
+	struct cn_ctl_entry *ent;
+
+	spin_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 a, b;
+
+		a = b = 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) {
+				a = 1;
+				break;
+			}
+		}
+		
+		for (i=0; i<ctl->val_notify_num; ++i, ++req) {
+			if (id->val >= req->first && id->val < req->first + req->range) {
+				b = 1;
+				break;
+			}
+		}
+
+		if (a && b) {
+			struct cn_msg m;
+			
+			printk(KERN_INFO "Notifying group %x with event %u about %x.%x.\n", 
+					ctl->group, notify_event, 
+					id->idx, id->val);
+
+			memset(&m, 0, sizeof(m));
+			m.ack = notify_event;
+
+			memcpy(&m.id, id, sizeof(m.id));
+			cn_netlink_send(&m, ctl->group);
+		}
+	}
+	spin_unlock(&notify_lock);
+}
+
+int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *))
+{
+	int err;
+	struct cn_dev *dev = &cdev;
+	struct cn_callback *cb;
+
+	cb = kmalloc(sizeof(*cb), GFP_KERNEL);
+	if (!cb) {
+		printk(KERN_INFO "%s: Failed to allocate new struct cn_callback.\n",
+		       dev->cbdev->name);
+		return -ENOMEM;
+	}
+
+	memset(cb, 0, sizeof(*cb));
+
+	snprintf(cb->name, sizeof(cb->name), "%s", name);
+
+	memcpy(&cb->id, id, sizeof(cb->id));
+	cb->callback = callback;
+
+	atomic_set(&cb->refcnt, 0);
+
+	err = cn_queue_add_callback(dev->cbdev, cb);
+	if (err) {
+		kfree(cb);
+		return err;
+	}
+			
+	cn_notify(id, 0);
+
+	return 0;
+}
+
+void cn_del_callback(struct cb_id *id)
+{
+	struct cn_dev *dev = &cdev;
+	struct cn_callback_entry *n, *__cbq;
+
+	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
+		if (cn_cb_equal(&__cbq->cb->id, id)) {
+			cn_queue_del_callback(dev->cbdev, __cbq->cb);
+			cn_notify(id, 1);
+			break;
+		}
+	}
+}
+
+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) {
+		printk(KERN_ERR "Notify entry[idx_num=%x, val_num=%x, len=%u] contains garbage. Removing.\n", 
+				m1->idx_notify_num, m1->val_notify_num, 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 (memcmp(req1, req2, sizeof(*req1)))
+			return 0;
+
+		req1++;
+		req2++;
+	}
+
+	for (i=0; i<m1->val_notify_num; ++i) {
+		if (memcmp(req1, req2, sizeof(*req1)))
+			return 0;
+
+		req1++;
+		req2++;
+	}
+
+	return 1;
+}
+
+static void cn_callback(void * data)
+{
+	struct cn_msg *msg = (struct cn_msg *)data;
+	struct cn_ctl_msg *ctl;
+	struct cn_ctl_entry *ent;
+	u32 size;
+ 
+	if (msg->len < sizeof(*ctl)) {
+		printk(KERN_ERR "Wrong connector request size %u, must be >= %u.\n", 
+				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) {
+		printk(KERN_ERR "Wrong connector request size %u, must be == %u.\n", 
+				msg->len, size);
+		return;
+	}
+
+	if (ctl->len + sizeof(*ctl) != msg->len) {
+		printk(KERN_ERR "Wrong message: msg->len=%u must be equal to inner_len=%u [+%u].\n", 
+				msg->len, ctl->len, sizeof(*ctl));
+		return;
+	}
+
+	/*
+	 * Remove notification.
+	 */
+	if (ctl->group == 0) {
+		struct cn_ctl_entry *n;
+		
+		spin_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);
+			}
+		}
+		spin_unlock(&notify_lock);
+
+		return;
+	}
+
+	size += sizeof(*ent);
+
+	ent = kmalloc(size, GFP_ATOMIC);
+	if (!ent) {
+		printk(KERN_ERR "Failed to allocate %d bytes for new notify entry.\n", size);
+		return;
+	}
+
+	memset(ent, 0, size);
+
+	ent->msg = (struct cn_ctl_msg *)(ent + 1);
+
+	memcpy(ent->msg, ctl, size - sizeof(*ent));
+
+	spin_lock(&notify_lock);
+	list_add(&ent->notify_entry, &notify_list);
+	spin_unlock(&notify_lock);
+
+	{
+		int i;
+		struct cn_notify_req *req;
+	
+		printk("Notify group %x for idx: ", ctl->group);
+
+		req = (struct cn_notify_req *)ctl->data;
+		for (i=0; i<ctl->idx_notify_num; ++i, ++req)
+		{
+			printk("%u-%u ", req->first, req->first+req->range-1);
+		}
+		
+		printk("\nNotify group %x for val: ", ctl->group);
+
+		for (i=0; i<ctl->val_notify_num; ++i, ++req)
+		{
+			printk("%u-%u ", req->first, req->first+req->range-1);
+		}
+		printk("\n");
+	}
+}
+
+static int cn_init(void)
+{
+	struct cn_dev *dev = &cdev;
+
+	dev->input = cn_input;
+	dev->id.idx = cn_idx;
+	dev->id.val = cn_val;
+
+	dev->nls = netlink_kernel_create(unit, dev->input);
+	if (!dev->nls) {
+		printk(KERN_ERR "Failed to create new netlink socket(%u).\n",
+		       unit);
+		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;
+	}
+
+	return cn_add_callback(&dev->id, "connector", &cn_callback);
+}
+
+static void cn_fini(void)
+{
+	struct cn_dev *dev = &cdev;
+
+	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(cn_add_callback);
+EXPORT_SYMBOL(cn_del_callback);
+EXPORT_SYMBOL(cn_netlink_send);
diff -Nru /tmp/empty/connector.h linux-2.6/drivers/connector/connector.h
--- /tmp/empty/connector.h	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/connector.h	2004-09-21 13:38:57.000000000 +0400
@@ -0,0 +1,81 @@
+/*
+ * 	connector.h
+ * 
+ * 2004 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
+ */
+
+#ifndef __CONNECTOR_H
+#define __CONNECTOR_H
+
+#include "../connector/cn_queue.h"
+
+#define CONNECTOR_MAX_MSG_SIZE 	1024
+
+struct cn_msg
+{
+	struct cb_id 		id;
+
+	__u32			seq;
+	__u32			ack;
+
+	__u32			len;		/* Length of the following data */
+	__u8			data[0];
+};
+
+struct cn_notify_req
+{
+	__u32			first;
+	__u32			range;
+};
+
+struct cn_ctl_msg
+{
+	__u32			idx_notify_num;
+	__u32			val_notify_num;
+	__u32			group;
+	__u32			len;
+	__u8			data[0];
+};
+
+#ifdef __KERNEL__
+
+#include <net/sock.h>
+
+struct cn_ctl_entry
+{
+	struct list_head	notify_entry;
+	struct cn_ctl_msg	*msg;
+};
+
+struct cn_dev
+{
+	struct cb_id 		id;
+
+	u32			seq, groups;
+	struct sock 		*nls;
+	void 			(*input)(struct sock *sk, int len);
+
+	struct cn_queue_dev	*cbdev;
+};
+
+int cn_add_callback(struct cb_id *, char *, void (* callback)(void *));
+void cn_del_callback(struct cb_id *);
+void cn_netlink_send(struct cn_msg *, u32);
+
+#endif /* __KERNEL__ */
+#endif /* __CONNECTOR_H */


--
	Evgeniy Polyakov

Crash is better than data corruption. -- Artur Grabowski

[-- Attachment #2: cn_test.c --]
[-- Type: text/plain, Size: 3519 bytes --]

/*
 * 	cn_test.c
 * 
 * 2004 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/moduleparam.h>
#include <linux/skbuff.h>

#include "connector.h"

static struct cb_id cn_test_id = { 0x123, 0x456 };
static char cn_test_name[] = "cn_test";
static struct sock *nls;

void cn_test_callback(void *data)
{
	struct cn_msg *msg = (struct cn_msg *)data;

	printk("%s: idx=%x, val=%x, len=%d.\n",
	       __func__, msg->id.idx, msg->id.val, msg->len);
}

static int cn_test_want_notify(void)
{
	struct cn_ctl_msg *ctl;
	struct cn_notify_req *req;
	struct cn_msg *msg = NULL;
	int size, size0;
	struct sk_buff *skb;
	struct nlmsghdr *nlh;
	u32 group = 1;

	size0 = sizeof(*msg) + sizeof(*ctl) + 3*sizeof(*req);
	
	size = NLMSG_SPACE(size0);

	skb = alloc_skb(size, GFP_ATOMIC);
	if (!skb) {
		printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", size);

		return -ENOMEM;
	}

	nlh = NLMSG_PUT(skb, 0, 0x123, NLMSG_DONE, size - sizeof(*nlh));

	msg = (struct cn_msg *)NLMSG_DATA(nlh);

	memset(msg, 0, size0);

	msg->id.idx 	= -1;
	msg->id.val 	= -1;
	msg->seq 	= 0x123;
	msg->ack 	= 0x345;
	msg->len 	= size0 - sizeof(*msg);

	ctl = (struct cn_ctl_msg *)(msg + 1);

	ctl->idx_notify_num 	= 1;
	ctl->val_notify_num 	= 2;
	ctl->group		= group;
	ctl->len		= msg->len - sizeof(*ctl);

	req = (struct cn_notify_req *)(ctl + 1);

	/*
	 * Idx.
	 */
	req->first = cn_test_id.idx;
	req->range = 10;

	/*
	 * Val 0.
	 */
	req++;
	req->first = cn_test_id.val;
	req->range = 10;
	
	/*
	 * Val 1.
	 */
	req++;
	req->first = cn_test_id.val + 20;
	req->range = 10;
	
	NETLINK_CB(skb).dst_groups = ctl->group;
	//netlink_broadcast(nls, skb, 0, ctl->group, GFP_ATOMIC);
	netlink_unicast(nls, skb, 0, 0);

	printk(KERN_INFO "Request was sent. Group=0x%x.\n", group);
		
	return 0;

nlmsg_failure:
	printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack);
	kfree_skb(skb);
	return -EINVAL;
}

static int cn_test_init(void)
{
	int err;
	
	nls = netlink_kernel_create(NETLINK_NFLOG, NULL);
	if (!nls) {
		printk(KERN_ERR "Failed to create new netlink socket(%u).\n", NETLINK_NFLOG);
		return -EIO;
	}

	err = cn_test_want_notify();
	if (err)
		goto err_out;

	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
	if (err)
		goto err_out;
	cn_test_id.val++;
	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
	if (err) {
		cn_del_callback(&cn_test_id);
		goto err_out;
	}

	return 0;

err_out:
	if (nls->sk_socket)
		sock_release(nls->sk_socket);

	return err;
}

static void cn_test_fini(void)
{
	cn_del_callback(&cn_test_id);
	cn_test_id.val--;
	cn_del_callback(&cn_test_id);
	if (nls->sk_socket)
		sock_release(nls->sk_socket);
}

module_init(cn_test_init);
module_exit(cn_test_fini);

[-- Attachment #3: ucon.c --]
[-- Type: text/plain, Size: 4324 bytes --]

/*
 * 	ucon.c
 *
 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
 * 
 *
 * 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 <asm/types.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/poll.h>

#include <linux/netlink.h>
#include <linux/rtnetlink.h>

#include <arpa/inet.h>

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <time.h>

#include "connector.h"
#include "../soekris/sc_conn.h"

static int need_exit;
__u32 seq;

static int netlink_send(int s, char *data)
{
	struct nlmsghdr *nlh;
	unsigned int size;
	int err;
	char buf[128];
	struct cn_msg *m, *msg;
	struct sc_conn_data *cmd;

	size = NLMSG_SPACE(sizeof(struct cn_msg) + sizeof(struct sc_conn_data));

	nlh = (struct nlmsghdr *)buf;
	nlh->nlmsg_seq = seq++;
	nlh->nlmsg_pid = getpid();
	nlh->nlmsg_type = NLMSG_DONE;
	nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
	nlh->nlmsg_flags = 0;

	m = NLMSG_DATA(nlh);
	msg = (struct cn_msg *)data;
	cmd = (struct sc_conn_data *)(msg + 1);

	printf("%s: len=%u, seq=%u, ack=%u, "
	       "sname=%s, lname=%s, idx=0x%x, cmd=%02x [%02x.%02x.%02x].\n",
	       __func__,
	       msg->len, msg->seq, msg->ack,
	       cmd->sname,
	       cmd->lname, cmd->idx, cmd->cmd, cmd->p0, cmd->p1, cmd->p2);

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

	err = send(s, nlh, size, 0);
	if (err == -1)
		fprintf(stderr, "Failed to send: %s [%d].\n",
			strerror(errno), errno);

	return err;
}

int main(int argc, char *argv[])
{
	int s;
	char buf[1024];
	int len;
	struct nlmsghdr *reply;
	struct sockaddr_nl l_local;
	struct cn_msg *data;
	struct sc_conn_data *m;
	FILE *out;
	time_t tm;
	struct pollfd pfd;

	if (argc < 2)
		out = stdout;
	else {
		out = fopen(argv[1], "a+");
		if (!out) {
			fprintf(stderr, "Unable to open %s for writing: %s\n",
				argv[1], strerror(errno));
			out = stdout;
		}
	}

	memset(buf, 0, sizeof(buf));

	s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_NFLOG);
	if (s == -1) {
		perror("socket");
		return -1;
	}

	l_local.nl_family = AF_NETLINK;
	l_local.nl_groups = 1;
	l_local.nl_pid = getpid();

	if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) == -1) {
		perror("bind");
		close(s);
		return -1;
	}

	pfd.fd = s;

	while (!need_exit) {
		pfd.events = POLLIN;
		pfd.revents = 0;
		/*switch (poll(&pfd, 1, -1)) 
		   {
		   case 0:
		   need_exit = 1;
		   break;
		   case -1:
		   if (errno != EINTR) 
		   {
		   need_exit = 1;
		   break;
		   }
		   continue;
		   } */
		if (need_exit)
			break;

		data = (struct cn_msg *)buf;

		data->id.idx = 0xaabb;
		data->id.val = 0xccdd;
		data->seq = seq++;
		data->ack = (seq ^ 0x1234);
		data->len = sizeof(*m);

		m = (struct sc_conn_data *)(data + 1);
		memset(m, 0, sizeof(*m));

		m->cmd = SC_CMD_LDEV_READ;
		m->idx = 0xff;
		sprintf(m->sname, "PC8736X");
		sprintf(m->lname, "GPIO");

		m->p0 = 21;

		len = netlink_send(s, buf);

		len = recv(s, buf, sizeof(buf), 0);
		if (len == -1) {
			perror("recv buf");
			close(s);
			return -1;
		}
		reply = (struct nlmsghdr *)buf;

		switch (reply->nlmsg_type) {
		case NLMSG_ERROR:
			fprintf(out, "Error message received.\n");
			fflush(out);
			break;
		case NLMSG_DONE:
			data = (struct cn_msg *)NLMSG_DATA(reply);
			m = (struct sc_conn_data *)(data + 1);

			time(&tm);
			fprintf(out,
				"%.24s : [%x.%x] [seq=%u, ack=%u], sname=%s, lname=%s, idx=%u, cmd=%#02x [%#02x.%#02x.%#02x]\n",
				ctime(&tm), data->id.idx, data->id.val,
				data->seq, data->ack, m->sname, m->lname,
				m->idx, m->cmd, m->p0, m->p1, m->p2);
			fflush(out);
			break;
		default:
			break;
		}

		sleep(1);
	}

	close(s);
	return 0;
}

Re: Kernel connector - userspace <-> kernelspace "linker".

[Richard B. Johnson]

Hello,
This looks like a thinly veiled attempt to provide kernel
hooks so that non-GPL user-mode code can execute within
the kernel and trash it. I think the kernel developers
are smart enough so they won't allow any priviliged
kernel-mode 'callback' to user code.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.26 on an i686 machine (5570.56 BogoMips).
            Note 96.31% of all statistics are fiction.

Re: Kernel connector - userspace <-> kernelspace "linker".

[Buddy Lucas]

On Tue, 21 Sep 2004 13:22:35 +0100, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> On Maw, 2004-09-21 at 13:46, Evgeniy Polyakov wrote:
> > Connector driver adds possibility to connect various agents using
> > netlink based network.
> > One must register callback and identificator. When driver receives
> > special netlink message with appropriate identificator, appropriate
> > callback will be called.
> 
> Looks sane enough to me - and it seems to fit the mentality d-bus and
> HAL want to have.
> 
> Alan
> 
> ps: only trivial item (and really trivial) is that the printk messages
> should be "waiting for %s".
> 

Actually, it should be "waiting for %s to become", not "became". ;-)

Also -- yes, I'm really nitpicking but Evgeniy asked for it ;-) --
brace after for() should not be on a new line. And
s/allocte/allocate/.

That's it for me, nice one, Evgeniy. ;-)


Cheers,
Buddy

> 
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>

Re: Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

On Tue, 21 Sep 2004 08:54:54 -0400 (EDT)
"Richard B. Johnson" <root@chaos.analogic.com> wrote:

> 
> Hello,
> This looks like a thinly veiled attempt to provide kernel
> hooks so that non-GPL user-mode code can execute within
> the kernel and trash it. I think the kernel developers
> are smart enough so they won't allow any priviliged
> kernel-mode 'callback' to user code.

Bugha-gha,  I like you :)

It _is_ the way to use GPL only work_queues and to put trojan horses.
You've cracked me.
Btw, do you know, that ioctl is the way to call "any priviliged
kernel-mode 'callback' to user code" too?

Actually one can implement it in it's binary only driver by itself, 
it just requres some netlink/skbuff knowledge.
Since binary-only modules do not implement the same low level protocol
twice(that's why they are binary _only_), it will not cost too much for
their authors.

And, last ironic note:

extern void (*private_binary_only_callback)(void *);
int day_of_the_hell = HZ;
module_param(day_of_the_hell, int, 0);

int bi()
{
  init_timer(&bt);
  bt.function = private_binary_only_callback;
  bt.expires = jiffies + day_of_the_hell;
  bt.data = NULL;
  add_timer(&bt);
}

void fi()
{
  del_timer_sync(&bt);
}

module_init(bi);
module_exit(fi);

or something...


Sigh, and noone abolished EXPORT_SYMBOL_GPL();


> Cheers,
> Dick Johnson
> Penguin : Linux version 2.4.26 on an i686 machine (5570.56 BogoMips).
>             Note 96.31% of all statistics are fiction.


	Evgeniy Polyakov ( s0mbre )

Only failure makes us experts. -- Theo de Raadt

Re: Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

On Tue, 21 Sep 2004 13:22:35 +0100
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> On Maw, 2004-09-21 at 13:46, Evgeniy Polyakov wrote:
> > Connector driver adds possibility to connect various agents using
> > netlink based network.
> > One must register callback and identificator. When driver receives
> > special netlink message with appropriate identificator, appropriate
> > callback will be called.
> 
> Looks sane enough to me - and it seems to fit the mentality d-bus and
> HAL want to have. 
> 
> Alan
> 
> ps: only trivial item (and really trivial) is that the printk messages
> should be "waiting for %s".

:) Sure. If it will be in the kernel, it will not contain errors.


	Evgeniy Polyakov

Only failure makes us experts. -- Theo de Raadt

[1/1] connector: Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

Connector driver adds possibility to connect various agents using
netlink based network.
One must register callback and identificator. When driver receives
special netlink message with appropriate identificator, appropriate
callback will be called.

>From the userspace point of view it's quite straightforward:
socket();
bind();
send();
recv();

But if kernespace want to use full power of such connections, driver 
writer must create special sockets, must know about struct skbuff 
handling...
Following driver allows any kernelspace agents to use netlink based 
networking for inter-process communication in a significantly easier 
way:

register_callback(id, callback_function);
cn_connector_send();

where id is currently two 32bit values which can be considered as
name + id.

Current driver offers just transport layer but with fixed header.
Recommended protocol using such header is following:

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 sequence number in received 
message MUST be the same as in original message, and acknowledge 
number MUST be the same + 1.

If we receive message and it's sequence number is not equal to one 
we are expecting, then it is new message.
If we receive message and it's sequence number is the same as one we 
are expecting, but it's acknowledge is not equal acknowledge number 
in original message + 1, then it is new message.

Obviously, protocol header contains above id.

As a bonus, suggested by Jamal Hadi Salim in netdev@ maillist, 
connector driver allows event notification in the following form:
kernel driver or userspace process can ask connector to notify it 
when selected id's will be turned on or off(registered or unregistered 
it's callback). It is done by sending special command to connector 
driver(it also registers itself with id={-1, -1}).

Created schema contains large reserve for different future extensions.

All previous mentioned problems are successfully resolved.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>

--- linux-2.6/drivers/Makefile.orig	2004-09-12 01:14:07.000000000 +0400
+++ linux-2.6/drivers/Makefile	2004-09-11 22:49:32.000000000 +0400
@@ -43,6 +43,7 @@
 obj-$(CONFIG_I2O)		+= message/
 obj-$(CONFIG_I2C)		+= i2c/
 obj-$(CONFIG_W1)		+= w1/
+obj-$(CONFIG_CONNECTOR)	+= connector/
 obj-$(CONFIG_PHONE)		+= telephony/
 obj-$(CONFIG_MD)		+= md/
 obj-$(CONFIG_BT)		+= bluetooth/


--- linux-2.6/drivers/Kconfig	2004-09-21 13:56:46.000000000 +0400
+++ linux-2.6/drivers/Kconfig.orig	2004-09-21 13:55:18.000000000 +0400
@@ -44,6 +44,8 @@
 
 source "drivers/w1/Kconfig"
 
+source "drivers/connector/Kconfig"
+
 source "drivers/misc/Kconfig"
 
 source "drivers/media/Kconfig"

diff -Nru /tmp/empty/Kconfig linux-2.6/drivers/connector/Kconfig
--- /tmp/empty/Kconfig	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/Kconfig	2004-09-09 08:43:37.000000000 +0400
@@ -0,0 +1,13 @@
+menu "Connector - unified userspace <-> kernelspace linker"
+
+config CONNECTOR
+	tristate "Connector - unified userspace <-> kernelspace linker"
+	depends on NET
+	---help---
+	  This is unified userspace <-> kernelspace connector working on top
+	  of the netlink socket protocol.
+
+	  Connector support can also be built as a module.  If so, the module
+	  will be called connector.ko.
+
+endmenu
diff -Nru /tmp/empty/Makefile linux-2.6/drivers/connector/Makefile
--- /tmp/empty/Makefile	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/Makefile	2004-09-10 08:59:26.000000000 +0400
@@ -0,0 +1,2 @@
+obj-$(CONFIG_CONNECTOR)		+= cn.o
+cn-objs		:= cn_queue.o connector.o
diff -Nru /tmp/empty/cn_queue.c linux-2.6/drivers/connector/cn_queue.c
--- /tmp/empty/cn_queue.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/cn_queue.c	2004-09-24 00:01:00.000000000 +0400
@@ -0,0 +1,218 @@
+/*
+ * 	cn_queue.c
+ * 
+ * 2004 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/workqueue.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+#include <linux/suspend.h>
+
+#include "cn_queue.h"
+
+static void cn_queue_wrapper(void *data)
+{
+	struct cn_callback_entry *cbq = (struct cn_callback_entry *)data;
+
+	atomic_inc(&cbq->cb->refcnt);
+	cbq->cb->callback(cbq->cb->priv);
+	atomic_dec(&cbq->cb->refcnt);
+
+	cbq->destruct_data(cbq->ddata);
+}
+
+static struct cn_callback_entry *cn_queue_alloc_callback_entry(struct
+							       cn_callback *cb)
+{
+	struct cn_callback_entry *cbq;
+
+	cbq = kmalloc(sizeof(*cbq), GFP_KERNEL);
+	if (!cbq) {
+		printk(KERN_ERR "Failed to create new callback queue.\n");
+		return NULL;
+	}
+
+	memset(cbq, 0, sizeof(*cbq));
+
+	cbq->cb = cb;
+
+	INIT_WORK(&cbq->work, &cn_queue_wrapper, cbq);
+
+	return cbq;
+}
+
+static void cn_queue_free_callback(struct cn_callback_entry *cbq)
+{
+	cancel_delayed_work(&cbq->work);
+
+	while (atomic_read(&cbq->cb->refcnt)) {
+		printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
+		       cbq->pdev->name, atomic_read(&cbq->cb->refcnt));
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(HZ);
+
+		if (current->flags & PF_FREEZE)
+			refrigerator(PF_FREEZE);
+
+		if (signal_pending(current))
+			flush_signals(current);
+	}
+
+	kfree(cbq);
+}
+
+int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
+{
+	return ((i1->idx == i2->idx) && (i1->val == i2->val));
+}
+
+int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb)
+{
+	struct cn_callback_entry *cbq, *n, *__cbq;
+	int found = 0;
+
+	cbq = cn_queue_alloc_callback_entry(cb);
+	if (!cbq)
+		return -ENOMEM;
+
+	atomic_inc(&dev->refcnt);
+	cbq->pdev = dev;
+
+	spin_lock(&dev->queue_lock);
+	list_for_each_entry_safe(__cbq, n, &dev->queue_list, callback_entry) {
+		if (cn_cb_equal(&__cbq->cb->id, &cb->id)) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found) {
+		atomic_set(&cbq->cb->refcnt, 1);
+		list_add_tail(&cbq->callback_entry, &dev->queue_list);
+	}
+	spin_unlock(&dev->queue_lock);
+
+	if (found) {
+		atomic_dec(&dev->refcnt);
+		atomic_set(&cbq->cb->refcnt, 0);
+		cn_queue_free_callback(cbq);
+		return -EINVAL;
+	}
+
+	cbq->nls = dev->nls;
+	cbq->seq = 0;
+	cbq->group = ++dev->netlink_groups;
+
+	return 0;
+}
+
+void cn_queue_del_callback(struct cn_queue_dev *dev, struct cn_callback *cb)
+{
+	struct cn_callback_entry *cbq = NULL, *n;
+	int found = 0;
+
+	spin_lock(&dev->queue_lock);
+	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
+		if (cn_cb_equal(&cbq->cb->id, &cb->id)) {
+			list_del(&cbq->callback_entry);
+			found = 1;
+			break;
+		}
+	}
+	spin_unlock(&dev->queue_lock);
+
+	if (found) {
+		atomic_dec(&cbq->cb->refcnt);
+		cn_queue_free_callback(cbq);
+		atomic_dec(&dev->refcnt);
+	}
+}
+
+struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls)
+{
+	struct cn_queue_dev *dev;
+
+	dev = kmalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev) {
+		printk(KERN_ERR "%s: Failed to allocte new struct cn_queue_dev.\n",
+		       name);
+		return NULL;
+	}
+
+	memset(dev, 0, sizeof(*dev));
+
+	snprintf(dev->name, sizeof(dev->name), "%s", name);
+
+	atomic_set(&dev->refcnt, 0);
+	INIT_LIST_HEAD(&dev->queue_list);
+	spin_lock_init(&dev->queue_lock);
+
+	dev->nls = nls;
+	dev->netlink_groups = 0;
+
+	dev->cn_queue = create_workqueue(dev->name);
+	if (!dev->cn_queue) {
+		printk(KERN_ERR "Failed to create %s queue.\n", dev->name);
+		kfree(dev);
+		return NULL;
+	}
+
+	return dev;
+}
+
+void cn_queue_free_dev(struct cn_queue_dev *dev)
+{
+	struct cn_callback_entry *cbq, *n;
+
+	flush_workqueue(dev->cn_queue);
+	destroy_workqueue(dev->cn_queue);
+
+	spin_lock(&dev->queue_lock);
+	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
+		list_del(&cbq->callback_entry);
+		atomic_dec(&cbq->cb->refcnt);
+	}
+	spin_unlock(&dev->queue_lock);
+
+	while (atomic_read(&dev->refcnt)) {
+		printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n",
+		       dev->name, atomic_read(&dev->refcnt));
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(HZ);
+
+		if (current->flags & PF_FREEZE)
+			refrigerator(PF_FREEZE);
+
+		if (signal_pending(current))
+			flush_signals(current);
+	}
+
+	memset(dev, 0, sizeof(*dev));
+	kfree(dev);
+	dev = NULL;
+}
+
+EXPORT_SYMBOL(cn_queue_add_callback);
+EXPORT_SYMBOL(cn_queue_del_callback);
+EXPORT_SYMBOL(cn_queue_alloc_dev);
+EXPORT_SYMBOL(cn_queue_free_dev);
diff -Nru /tmp/empty/cn_queue.h linux-2.6/drivers/connector/cn_queue.h
--- /tmp/empty/cn_queue.h	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/cn_queue.h	2004-09-21 13:38:57.000000000 +0400
@@ -0,0 +1,90 @@
+/*
+ * 	cn_queue.h
+ * 
+ * 2004 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
+ */
+
+#ifndef __CN_QUEUE_H
+#define __CN_QUEUE_H
+
+#include <asm/types.h>
+
+struct cb_id
+{
+	__u32			idx;
+	__u32			val;
+};
+
+#ifdef __KERNEL__
+
+#include <asm/atomic.h>
+
+#include <linux/list.h>
+#include <linux/workqueue.h>
+
+#define CN_CBQ_NAMELEN		32
+
+struct cn_queue_dev
+{
+	atomic_t		refcnt;
+	unsigned char		name[CN_CBQ_NAMELEN];
+
+	struct workqueue_struct	*cn_queue;
+	
+	struct list_head 	queue_list;
+	spinlock_t 		queue_lock;
+
+	int			netlink_groups;
+	struct sock		*nls;
+};
+
+struct cn_callback
+{
+	unsigned char		name[CN_CBQ_NAMELEN];
+	
+	struct cb_id		id;
+	void			(* callback)(void *);
+	void			*priv;
+	
+	atomic_t		refcnt;
+};
+
+struct cn_callback_entry
+{
+	struct list_head	callback_entry;
+	struct cn_callback	*cb;
+	struct work_struct	work;
+	struct cn_queue_dev	*pdev;
+	
+	void			(* destruct_data)(void *);
+	void			*ddata;
+
+	int			seq, group;
+	struct sock		*nls;
+};
+
+int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb);
+void cn_queue_del_callback(struct cn_queue_dev *dev, struct cn_callback *cb);
+
+struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *);
+void cn_queue_free_dev(struct cn_queue_dev *dev);
+
+int cn_cb_equal(struct cb_id *, struct cb_id *);
+
+#endif /* __KERNEL__ */
+#endif /* __CN_QUEUE_H */
diff -Nru /tmp/empty/cn_test.c linux-2.6/drivers/connector/cn_test.c
--- /tmp/empty/cn_test.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/cn_test.c	2004-09-21 13:38:57.000000000 +0400
@@ -0,0 +1,160 @@
+/*
+ * 	cn_test.c
+ * 
+ * 2004 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/moduleparam.h>
+#include <linux/skbuff.h>
+
+#include "connector.h"
+
+static struct cb_id cn_test_id = { 0x123, 0x456 };
+static char cn_test_name[] = "cn_test";
+static struct sock *nls;
+
+void cn_test_callback(void *data)
+{
+	struct cn_msg *msg = (struct cn_msg *)data;
+
+	printk("%s: idx=%x, val=%x, len=%d.\n",
+	       __func__, msg->id.idx, msg->id.val, msg->len);
+}
+
+static int cn_test_want_notify(void)
+{
+	struct cn_ctl_msg *ctl;
+	struct cn_notify_req *req;
+	struct cn_msg *msg = NULL;
+	int size, size0;
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+	u32 group = 1;
+
+	size0 = sizeof(*msg) + sizeof(*ctl) + 3*sizeof(*req);
+	
+	size = NLMSG_SPACE(size0);
+
+	skb = alloc_skb(size, GFP_ATOMIC);
+	if (!skb) {
+		printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", size);
+
+		return -ENOMEM;
+	}
+
+	nlh = NLMSG_PUT(skb, 0, 0x123, NLMSG_DONE, size - sizeof(*nlh));
+
+	msg = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	memset(msg, 0, size0);
+
+	msg->id.idx 	= -1;
+	msg->id.val 	= -1;
+	msg->seq 	= 0x123;
+	msg->ack 	= 0x345;
+	msg->len 	= size0 - sizeof(*msg);
+
+	ctl = (struct cn_ctl_msg *)(msg + 1);
+
+	ctl->idx_notify_num 	= 1;
+	ctl->val_notify_num 	= 2;
+	ctl->group		= group;
+	ctl->len		= msg->len - sizeof(*ctl);
+
+	req = (struct cn_notify_req *)(ctl + 1);
+
+	/*
+	 * Idx.
+	 */
+	req->first = cn_test_id.idx;
+	req->range = 10;
+
+	/*
+	 * Val 0.
+	 */
+	req++;
+	req->first = cn_test_id.val;
+	req->range = 10;
+	
+	/*
+	 * Val 1.
+	 */
+	req++;
+	req->first = cn_test_id.val + 20;
+	req->range = 10;
+	
+	NETLINK_CB(skb).dst_groups = ctl->group;
+	//netlink_broadcast(nls, skb, 0, ctl->group, GFP_ATOMIC);
+	netlink_unicast(nls, skb, 0, 0);
+
+	printk(KERN_INFO "Request was sent. Group=0x%x.\n", group);
+		
+	return 0;
+
+nlmsg_failure:
+	printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack);
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+static int cn_test_init(void)
+{
+	int err;
+	
+	nls = netlink_kernel_create(NETLINK_NFLOG, NULL);
+	if (!nls) {
+		printk(KERN_ERR "Failed to create new netlink socket(%u).\n", NETLINK_NFLOG);
+		return -EIO;
+	}
+
+	err = cn_test_want_notify();
+	if (err)
+		goto err_out;
+
+	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
+	if (err)
+		goto err_out;
+	cn_test_id.val++;
+	err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback);
+	if (err) {
+		cn_del_callback(&cn_test_id);
+		goto err_out;
+	}
+
+	return 0;
+
+err_out:
+	if (nls->sk_socket)
+		sock_release(nls->sk_socket);
+
+	return err;
+}
+
+static void cn_test_fini(void)
+{
+	cn_del_callback(&cn_test_id);
+	cn_test_id.val--;
+	cn_del_callback(&cn_test_id);
+	if (nls->sk_socket)
+		sock_release(nls->sk_socket);
+}
+
+module_init(cn_test_init);
+module_exit(cn_test_fini);
diff -Nru /tmp/empty/connector.c linux-2.6/drivers/connector/connector.c
--- /tmp/empty/connector.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/connector.c	2004-09-24 00:01:00.000000000 +0400
@@ -0,0 +1,498 @@
+/*
+ * 	connector.c
+ * 
+ * 2004 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 <net/sock.h>
+
+#include "../connector/connector.h"
+#include "../connector/cn_queue.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
+MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
+
+static int unit = NETLINK_NFLOG;
+static u32 cn_idx = -1;
+static u32 cn_val = -1;
+
+module_param(unit, int, 0);
+module_param(cn_idx, uint, 0);
+module_param(cn_val, uint, 0);
+
+spinlock_t notify_lock = SPIN_LOCK_UNLOCKED;
+static LIST_HEAD(notify_list);
+
+static struct cn_dev cdev;
+
+/*
+ * 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 sequence number in received message MUST be the same as in original message,
+ * and acknowledge number MUST be the same + 1.
+ *
+ * If we receive message and it's sequence number is not equal to one we are expecting, 
+ * then it is new message.
+ * If we receive message and it's sequence number is the same as one we are expecting,
+ * but it's acknowledge is not equal acknowledge number in original message + 1,
+ * then it is new message.
+ *
+ */
+void cn_netlink_send(struct cn_msg *msg, u32 __groups)
+{
+	struct cn_callback_entry *n, *__cbq;
+	unsigned int size;
+	struct sk_buff *skb;
+	struct nlmsghdr *nlh;
+	struct cn_msg *data;
+	struct cn_dev *dev = &cdev;
+	u32 groups = 0;
+	int found = 0;
+
+	if (!__groups)
+	{
+		spin_lock(&dev->cbdev->queue_lock);
+		list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
+			if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
+				found = 1;
+				groups = __cbq->group;
+			}
+		}
+		spin_unlock(&dev->cbdev->queue_lock);
+
+		if (!found) {
+			printk(KERN_ERR "Failed to find multicast netlink group for callback[0x%x.0x%x]. seq=%u\n",
+			       msg->id.idx, msg->id.val, msg->seq);
+			return;
+		}
+	}
+	else
+		groups = __groups;
+
+	size = NLMSG_SPACE(sizeof(*msg) + msg->len);
+
+	skb = alloc_skb(size, GFP_ATOMIC);
+	if (!skb) {
+		printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", size);
+		return;
+	}
+
+	nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
+
+	data = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	memcpy(data, msg, sizeof(*data) + msg->len);
+#if 0
+	printk("%s: len=%u, seq=%u, ack=%u, group=%u.\n",
+	       __func__, msg->len, msg->seq, msg->ack, groups);
+#endif
+	NETLINK_CB(skb).dst_groups = groups;
+	netlink_broadcast(dev->nls, skb, 0, groups, GFP_ATOMIC);
+
+	return;
+
+      nlmsg_failure:
+	printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack);
+	kfree_skb(skb);
+	return;
+}
+
+static int cn_call_callback(struct cn_msg *msg, void (*destruct_data) (void *), void *data)
+{
+	struct cn_callback_entry *n, *__cbq;
+	struct cn_dev *dev = &cdev;
+	int found = 0;
+
+	spin_lock(&dev->cbdev->queue_lock);
+	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
+		if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
+			__cbq->cb->priv = msg;
+
+			__cbq->ddata = data;
+			__cbq->destruct_data = destruct_data;
+
+			queue_work(dev->cbdev->cn_queue, &__cbq->work);
+			found = 1;
+			break;
+		}
+	}
+	spin_unlock(&dev->cbdev->queue_lock);
+
+	return found;
+}
+
+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)).groups;
+	msg = (struct cn_msg *)NLMSG_DATA(nlh);
+
+	if (msg->len != nlh->nlmsg_len - sizeof(*msg) - sizeof(*nlh)) {
+		printk(KERN_ERR "skb does not have enough length: "
+				"requested msg->len=%u[%u], nlh->nlmsg_len=%u[%u], skb->len=%u[must be %u].\n", 
+				msg->len, NLMSG_SPACE(msg->len), 
+				nlh->nlmsg_len, nlh->nlmsg_len - sizeof(*nlh),
+				skb->len, msg->len + sizeof(*msg));
+		return -EINVAL;
+	}
+#if 0
+	printk(KERN_INFO "pid=%u, uid=%u, seq=%u, group=%u.\n",
+	       pid, uid, seq, group);
+#endif
+	return cn_call_callback(msg, (void (*)(void *))kfree_skb, 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) {
+		printk(KERN_ERR "Failed to reference an skb.\n");
+		return;
+	}
+#if 0
+	printk(KERN_INFO
+	       "skb: len=%u, data_len=%u, truesize=%u, proto=%u, cloned=%d, shared=%d.\n",
+	       skb->len, skb->data_len, skb->truesize, skb->protocol,
+	       skb_cloned(skb), skb_shared(skb));
+#endif
+	while (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) {
+			printk(KERN_INFO "nlmsg_len=%u, sizeof(*nlh)=%u\n",
+			       nlh->nlmsg_len, sizeof(*nlh));
+			break;
+		}
+
+		len = NLMSG_ALIGN(nlh->nlmsg_len);
+		if (len > skb->len)
+			len = skb->len;
+
+		err = __cn_rx_skb(skb, nlh);
+		if (err) {
+#if 0
+			if (err < 0 && (nlh->nlmsg_flags & NLM_F_ACK))
+				netlink_ack(skb, nlh, -err);
+#endif
+			kfree_skb(skb);
+			break;
+		} else {
+#if 0
+			if (nlh->nlmsg_flags & NLM_F_ACK)
+				netlink_ack(skb, nlh, 0);
+#endif
+			kfree_skb(skb);
+			break;
+		}
+		skb_pull(skb, len);
+	}
+}
+
+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);
+}
+
+static void cn_notify(struct cb_id *id, u32 notify_event)
+{
+	struct cn_ctl_entry *ent;
+
+	spin_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 a, b;
+
+		a = b = 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) {
+				a = 1;
+				break;
+			}
+		}
+		
+		for (i=0; i<ctl->val_notify_num; ++i, ++req) {
+			if (id->val >= req->first && id->val < req->first + req->range) {
+				b = 1;
+				break;
+			}
+		}
+
+		if (a && b) {
+			struct cn_msg m;
+			
+			printk(KERN_INFO "Notifying group %x with event %u about %x.%x.\n", 
+					ctl->group, notify_event, 
+					id->idx, id->val);
+
+			memset(&m, 0, sizeof(m));
+			m.ack = notify_event;
+
+			memcpy(&m.id, id, sizeof(m.id));
+			cn_netlink_send(&m, ctl->group);
+		}
+	}
+	spin_unlock(&notify_lock);
+}
+
+int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *))
+{
+	int err;
+	struct cn_dev *dev = &cdev;
+	struct cn_callback *cb;
+
+	cb = kmalloc(sizeof(*cb), GFP_KERNEL);
+	if (!cb) {
+		printk(KERN_INFO "%s: Failed to allocate new struct cn_callback.\n",
+		       dev->cbdev->name);
+		return -ENOMEM;
+	}
+
+	memset(cb, 0, sizeof(*cb));
+
+	snprintf(cb->name, sizeof(cb->name), "%s", name);
+
+	memcpy(&cb->id, id, sizeof(cb->id));
+	cb->callback = callback;
+
+	atomic_set(&cb->refcnt, 0);
+
+	err = cn_queue_add_callback(dev->cbdev, cb);
+	if (err) {
+		kfree(cb);
+		return err;
+	}
+			
+	cn_notify(id, 0);
+
+	return 0;
+}
+
+void cn_del_callback(struct cb_id *id)
+{
+	struct cn_dev *dev = &cdev;
+	struct cn_callback_entry *n, *__cbq;
+
+	list_for_each_entry_safe(__cbq, n, &dev->cbdev->queue_list, callback_entry) {
+		if (cn_cb_equal(&__cbq->cb->id, id)) {
+			cn_queue_del_callback(dev->cbdev, __cbq->cb);
+			cn_notify(id, 1);
+			break;
+		}
+	}
+}
+
+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) {
+		printk(KERN_ERR "Notify entry[idx_num=%x, val_num=%x, len=%u] contains garbage. Removing.\n", 
+				m1->idx_notify_num, m1->val_notify_num, 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 (memcmp(req1, req2, sizeof(*req1)))
+			return 0;
+
+		req1++;
+		req2++;
+	}
+
+	for (i=0; i<m1->val_notify_num; ++i) {
+		if (memcmp(req1, req2, sizeof(*req1)))
+			return 0;
+
+		req1++;
+		req2++;
+	}
+
+	return 1;
+}
+
+static void cn_callback(void * data)
+{
+	struct cn_msg *msg = (struct cn_msg *)data;
+	struct cn_ctl_msg *ctl;
+	struct cn_ctl_entry *ent;
+	u32 size;
+ 
+	if (msg->len < sizeof(*ctl)) {
+		printk(KERN_ERR "Wrong connector request size %u, must be >= %u.\n", 
+				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) {
+		printk(KERN_ERR "Wrong connector request size %u, must be == %u.\n", 
+				msg->len, size);
+		return;
+	}
+
+	if (ctl->len + sizeof(*ctl) != msg->len) {
+		printk(KERN_ERR "Wrong message: msg->len=%u must be equal to inner_len=%u [+%u].\n", 
+				msg->len, ctl->len, sizeof(*ctl));
+		return;
+	}
+
+	/*
+	 * Remove notification.
+	 */
+	if (ctl->group == 0) {
+		struct cn_ctl_entry *n;
+		
+		spin_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);
+			}
+		}
+		spin_unlock(&notify_lock);
+
+		return;
+	}
+
+	size += sizeof(*ent);
+
+	ent = kmalloc(size, GFP_ATOMIC);
+	if (!ent) {
+		printk(KERN_ERR "Failed to allocate %d bytes for new notify entry.\n", size);
+		return;
+	}
+
+	memset(ent, 0, size);
+
+	ent->msg = (struct cn_ctl_msg *)(ent + 1);
+
+	memcpy(ent->msg, ctl, size - sizeof(*ent));
+
+	spin_lock(&notify_lock);
+	list_add(&ent->notify_entry, &notify_list);
+	spin_unlock(&notify_lock);
+
+	{
+		int i;
+		struct cn_notify_req *req;
+	
+		printk("Notify group %x for idx: ", ctl->group);
+
+		req = (struct cn_notify_req *)ctl->data;
+		for (i=0; i<ctl->idx_notify_num; ++i, ++req) {
+			printk("%u-%u ", req->first, req->first+req->range-1);
+		}
+		
+		printk("\nNotify group %x for val: ", ctl->group);
+
+		for (i=0; i<ctl->val_notify_num; ++i, ++req) {
+			printk("%u-%u ", req->first, req->first+req->range-1);
+		}
+		printk("\n");
+	}
+}
+
+static int cn_init(void)
+{
+	struct cn_dev *dev = &cdev;
+
+	dev->input = cn_input;
+	dev->id.idx = cn_idx;
+	dev->id.val = cn_val;
+
+	dev->nls = netlink_kernel_create(unit, dev->input);
+	if (!dev->nls) {
+		printk(KERN_ERR "Failed to create new netlink socket(%u).\n",
+		       unit);
+		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;
+	}
+
+	return cn_add_callback(&dev->id, "connector", &cn_callback);
+}
+
+static void cn_fini(void)
+{
+	struct cn_dev *dev = &cdev;
+
+	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(cn_add_callback);
+EXPORT_SYMBOL(cn_del_callback);
+EXPORT_SYMBOL(cn_netlink_send);
diff -Nru /tmp/empty/connector.h linux-2.6/drivers/connector/connector.h
--- /tmp/empty/connector.h	1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6/drivers/connector/connector.h	2004-09-21 13:38:57.000000000 +0400
@@ -0,0 +1,81 @@
+/*
+ * 	connector.h
+ * 
+ * 2004 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
+ */
+
+#ifndef __CONNECTOR_H
+#define __CONNECTOR_H
+
+#include "../connector/cn_queue.h"
+
+#define CONNECTOR_MAX_MSG_SIZE 	1024
+
+struct cn_msg
+{
+	struct cb_id 		id;
+
+	__u32			seq;
+	__u32			ack;
+
+	__u32			len;		/* Length of the following data */
+	__u8			data[0];
+};
+
+struct cn_notify_req
+{
+	__u32			first;
+	__u32			range;
+};
+
+struct cn_ctl_msg
+{
+	__u32			idx_notify_num;
+	__u32			val_notify_num;
+	__u32			group;
+	__u32			len;
+	__u8			data[0];
+};
+
+#ifdef __KERNEL__
+
+#include <net/sock.h>
+
+struct cn_ctl_entry
+{
+	struct list_head	notify_entry;
+	struct cn_ctl_msg	*msg;
+};
+
+struct cn_dev
+{
+	struct cb_id 		id;
+
+	u32			seq, groups;
+	struct sock 		*nls;
+	void 			(*input)(struct sock *sk, int len);
+
+	struct cn_queue_dev	*cbdev;
+};
+
+int cn_add_callback(struct cb_id *, char *, void (* callback)(void *));
+void cn_del_callback(struct cb_id *);
+void cn_netlink_send(struct cn_msg *, u32);
+
+#endif /* __KERNEL__ */
+#endif /* __CONNECTOR_H */


	Evgeniy Polyakov ( s0mbre )

Only failure makes us experts. -- Theo de Raadt

Re: [1/1] connector: Kernel connector - userspace <-> kernelspace "linker".

[Luis R. Rodriguez]

[-- Attachment #1: Type: text/plain, Size: 229 bytes --]


RFC: 

Can and should we work towards using this as interface for drivers that
need callbacks from an external (closed source) library/HAL?

-- 
GnuPG Key fingerprint = 113F B290 C6D2 0251 4D84  A34A 6ADD 4937 E20A 525E

[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]

Re: [1/1] connector: Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

[-- Attachment #1: Type: text/plain, Size: 1161 bytes --]

On Fri, 2004-09-24 at 01:54, Luis R. Rodriguez wrote:
> RFC: 
> 
> Can and should we work towards using this as interface for drivers that
> need callbacks from an external (closed source) library/HAL?

As I mentioned to Richard Jonson, it can be considered as
ioctl. ioctl-ng!
Unified interface (as ioctl) can be used for any type of modules.
It is just a bit extended ioctl :)

And _yes_, it can be used to turn on/off binary-only callbacks.
Remember pwc - closed part can register callback and open part can
send message, or even closed part can register notification when
open part registers itself and begin to "trash the kernel".

I understand that it is not right way to include it is into the kernel,
but I personally do not understand how it is different 
from just extended ioctl. It was designed to be usefull and convenient,
and it is.

BTW, any binary-only module can _itself_ create netlink socket
with input callback. And that is all - it will be absolutely
the same as above.

One may consider connector as yet-another-netlink-helper.

-- 
	Evgeniy Polyakov

Crash is better than data corruption. -- Art Grabowski

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Re: [1/1] connector: Kernel connector - userspace <-> kernelspace "linker".

[Luis R. Rodriguez]

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On Fri, Sep 24, 2004 at 07:40:32AM +0400, Evgeniy Polyakov wrote:
> On Fri, 2004-09-24 at 01:54, Luis R. Rodriguez wrote:
> > RFC: 
> > 
> > Can and should we work towards using this as interface for drivers that
> > need callbacks from an external (closed source) library/HAL?
> 
> As I mentioned to Richard Jonson, it can be considered as
> ioctl. ioctl-ng!
> Unified interface (as ioctl) can be used for any type of modules.
> It is just a bit extended ioctl :)
> 
> And _yes_, it can be used to turn on/off binary-only callbacks.
> Remember pwc - closed part can register callback and open part can
> send message, or even closed part can register notification when
> open part registers itself and begin to "trash the kernel".
> 
> I understand that it is not right way to include it is into the kernel,
> but I personally do not understand how it is different 
> from just extended ioctl. It was designed to be usefull and convenient,
> and it is.
> 
> BTW, any binary-only module can _itself_ create netlink socket
> with input callback. And that is all - it will be absolutely
> the same as above.
> 
> One may consider connector as yet-another-netlink-helper.
> 

Eh. I'm just wondering if there's any *right* way of using binary
callbacks on a linux driver so that it doesn't *taint* and possibly
*trash it*, as you said. I was wondering if perhaps through the
connector we could somehow protect the kernel of possibly ill-behaved callbacks.

Comments?

	Luis

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Re: [1/1] connector: Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

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On Fri, 2004-09-24 at 09:48, Luis R. Rodriguez wrote:
> On Fri, Sep 24, 2004 at 07:40:32AM +0400, Evgeniy Polyakov wrote:
> > On Fri, 2004-09-24 at 01:54, Luis R. Rodriguez wrote:
> > > RFC: 
> > > 
> > > Can and should we work towards using this as interface for drivers that
> > > need callbacks from an external (closed source) library/HAL?
> > 
> > As I mentioned to Richard Jonson, it can be considered as
> > ioctl. ioctl-ng!
> > Unified interface (as ioctl) can be used for any type of modules.
> > It is just a bit extended ioctl :)
> > 
> > And _yes_, it can be used to turn on/off binary-only callbacks.
> > Remember pwc - closed part can register callback and open part can
> > send message, or even closed part can register notification when
> > open part registers itself and begin to "trash the kernel".
> > 
> > I understand that it is not right way to include it is into the kernel,
> > but I personally do not understand how it is different 
> > from just extended ioctl. It was designed to be usefull and convenient,
> > and it is.
> > 
> > BTW, any binary-only module can _itself_ create netlink socket
> > with input callback. And that is all - it will be absolutely
> > the same as above.
> > 
> > One may consider connector as yet-another-netlink-helper.
> > 
> 
> Eh. I'm just wondering if there's any *right* way of using binary
> callbacks on a linux driver so that it doesn't *taint* and possibly
> *trash it*, as you said. I was wondering if perhaps through the
> connector we could somehow protect the kernel of possibly ill-behaved callbacks.
> 
> Comments?

Yes, we can.
Connector itself has quite enough information about it's registrants.

For example if it is somehow not good module( for example without GPL in
it's license string) then connector can be extended to call it's
callback from thread or in jail. If it is of interest I will think of
some plugable mechanism for callback environment( probably provide
->before_callback() and ->after_callback() methods from external policy
provider which may check callback data and/or confine callback execution
? ).

We also may confine closed modules from being able to use event
notification. In this scenario with worned out pwc-closed/open,
situation will not differ from what we have now.

> 	Luis
-- 
	Evgeniy Polyakov

Crash is better than data corruption. -- Art Grabowski

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Re: [1/1] connector: Kernel connector - userspace <-> kernelspace "linker".

[Evgeniy Polyakov]

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On Fri, 2004-09-24 at 10:14, Evgeniy Polyakov wrote:
> On Fri, 2004-09-24 at 09:48, Luis R. Rodriguez wrote:
> > On Fri, Sep 24, 2004 at 07:40:32AM +0400, Evgeniy Polyakov wrote:
> > > On Fri, 2004-09-24 at 01:54, Luis R. Rodriguez wrote:
> > > > RFC: 
> > > > 
> > > > Can and should we work towards using this as interface for drivers that
> > > > need callbacks from an external (closed source) library/HAL?
> > > 
> > > As I mentioned to Richard Jonson, it can be considered as
> > > ioctl. ioctl-ng!
> > > Unified interface (as ioctl) can be used for any type of modules.
> > > It is just a bit extended ioctl :)
> > > 
> > > And _yes_, it can be used to turn on/off binary-only callbacks.
> > > Remember pwc - closed part can register callback and open part can
> > > send message, or even closed part can register notification when
> > > open part registers itself and begin to "trash the kernel".
> > > 
> > > I understand that it is not right way to include it is into the kernel,
> > > but I personally do not understand how it is different 
> > > from just extended ioctl. It was designed to be usefull and convenient,
> > > and it is.
> > > 
> > > BTW, any binary-only module can _itself_ create netlink socket
> > > with input callback. And that is all - it will be absolutely
> > > the same as above.
> > > 
> > > One may consider connector as yet-another-netlink-helper.
> > > 
> > 
> > Eh. I'm just wondering if there's any *right* way of using binary
> > callbacks on a linux driver so that it doesn't *taint* and possibly
> > *trash it*, as you said. I was wondering if perhaps through the
> > connector we could somehow protect the kernel of possibly ill-behaved callbacks.
> > 
> > Comments?
> 
> Yes, we can.
> Connector itself has quite enough information about it's registrants.
> 
> For example if it is somehow not good module( for example without GPL in
> it's license string) then connector can be extended to call it's
> callback from thread or in jail. If it is of interest I will think of
> some plugable mechanism for callback environment( probably provide
> ->before_callback() and ->after_callback() methods from external policy
> provider which may check callback data and/or confine callback execution
> ? ).
> 
> We also may confine closed modules from being able to use event
> notification. In this scenario with worned out pwc-closed/open,
> situation will not differ from what we have now.

BTW, it can also restrict userspace event notification in following way:
when someone sends a message to notify group A of
registering/unregistering of device with id {x,y} then connector can
check if this group A is registered through callback_register_gpl(it is
not exist for now, but can be created as a copy of callback_register() )
or not. If it is GPL - send notify, else - execute 
"mail -s "shit happens" linux-kernel@vger.kernel.org" 
in the way /sbin/hotplug is called.
BTW, this decision also can be obtained from external policy module.

As you may think connector in current implementation is quite powerful
interface( if I will not praise it, who will? :) ), and somebody can
make bad things a bit easier with it, but it is also very flexible and
can be tuned to suit your needs.

I'm open for discussion :)

> > 	Luis
-- 
	Evgeniy Polyakov

Crash is better than data corruption. -- Art Grabowski

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Re: [1/1] connector: Kernel connector - userspace <-> kernelspace "linker".

[Luis R. Rodriguez]

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On Fri, Sep 24, 2004 at 10:30:04AM +0400, Evgeniy Polyakov wrote:
> On Fri, 2004-09-24 at 10:14, Evgeniy Polyakov wrote:
> > On Fri, 2004-09-24 at 09:48, Luis R. Rodriguez wrote:
> > > On Fri, Sep 24, 2004 at 07:40:32AM +0400, Evgeniy Polyakov wrote:
> > > > On Fri, 2004-09-24 at 01:54, Luis R. Rodriguez wrote:
> > > > > RFC: 
> > > > > 
> > > > > Can and should we work towards using this as interface for drivers that
> > > > > need callbacks from an external (closed source) library/HAL?
> > > > 
> > > > As I mentioned to Richard Jonson, it can be considered as
> > > > ioctl. ioctl-ng!
> > > > Unified interface (as ioctl) can be used for any type of modules.
> > > > It is just a bit extended ioctl :)
> > > > 
> > > > And _yes_, it can be used to turn on/off binary-only callbacks.
> > > > Remember pwc - closed part can register callback and open part can
> > > > send message, or even closed part can register notification when
> > > > open part registers itself and begin to "trash the kernel".
> > > > 
> > > > I understand that it is not right way to include it is into the kernel,
> > > > but I personally do not understand how it is different 
> > > > from just extended ioctl. It was designed to be usefull and convenient,
> > > > and it is.
> > > > 
> > > > BTW, any binary-only module can _itself_ create netlink socket
> > > > with input callback. And that is all - it will be absolutely
> > > > the same as above.
> > > > 
> > > > One may consider connector as yet-another-netlink-helper.
> > > > 
> > > 
> > > Eh. I'm just wondering if there's any *right* way of using binary
> > > callbacks on a linux driver so that it doesn't *taint* and possibly
> > > *trash it*, as you said. I was wondering if perhaps through the
> > > connector we could somehow protect the kernel of possibly ill-behaved callbacks.
> > > 
> > > Comments?
> > 
> > Yes, we can.
> > Connector itself has quite enough information about it's registrants.
> > 
> > For example if it is somehow not good module( for example without GPL in
> > it's license string) then connector can be extended to call it's
> > callback from thread or in jail. If it is of interest I will think of
> > some plugable mechanism for callback environment( probably provide
> > ->before_callback() and ->after_callback() methods from external policy
> > provider which may check callback data and/or confine callback execution
> > ? ).
> > 
> > We also may confine closed modules from being able to use event
> > notification. In this scenario with worned out pwc-closed/open,
> > situation will not differ from what we have now.
> 
> BTW, it can also restrict userspace event notification in following way:
> when someone sends a message to notify group A of
> registering/unregistering of device with id {x,y} then connector can
> check if this group A is registered through callback_register_gpl(it is
> not exist for now, but can be created as a copy of callback_register() )
> or not. If it is GPL - send notify, else - execute 
> "mail -s "shit happens" linux-kernel@vger.kernel.org" 
> in the way /sbin/hotplug is called.
> BTW, this decision also can be obtained from external policy module.
> 
> As you may think connector in current implementation is quite powerful
> interface( if I will not praise it, who will? :) ), and somebody can
> make bad things a bit easier with it, but it is also very flexible and
> can be tuned to suit your needs.
> 
> I'm open for discussion :)

Kernel maintainers: 

What do you think? Can a driver which requires access to binary
callbacks be included as part of the stock kernel as GPL if Evgeniy's
Connector provides some sort of kernel "jail" for the callback
functionality? 

	Luis

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Re: [1/1] connector: Kernel connector - userspace <-> kernelspace "linker".

[Luis R. Rodriguez]

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On Fri, Sep 24, 2004 at 02:32:31AM -0400, Luis R. Rodriguez wrote:
> On Fri, Sep 24, 2004 at 10:30:04AM +0400, Evgeniy Polyakov wrote:
> > 
> > BTW, it can also restrict userspace event notification in following way:
> > when someone sends a message to notify group A of
> > registering/unregistering of device with id {x,y} then connector can
> > check if this group A is registered through callback_register_gpl(it is
> > not exist for now, but can be created as a copy of callback_register() )
> > or not. If it is GPL - send notify, else - execute 
> > "mail -s "shit happens" linux-kernel@vger.kernel.org" 
> > in the way /sbin/hotplug is called.
> > BTW, this decision also can be obtained from external policy module.
> > 
> > As you may think connector in current implementation is quite powerful
> > interface( if I will not praise it, who will? :) ), and somebody can
> > make bad things a bit easier with it, but it is also very flexible and
> > can be tuned to suit your needs.
> > 
> > I'm open for discussion :)
> 
> Kernel maintainers: 
> 
> What do you think? Can a driver which requires access to binary
> callbacks be included as part of the stock kernel as GPL if Evgeniy's
> Connector provides some sort of kernel "jail" for the callback
> functionality? 
> 
> 	Luis
> 

BTW just wanted to say I realize all this is rediculous, I'm just
testing waters ;)

	Luis

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