Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6

/*

 * 	cn_test.c

 * 

 * 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>

 * All rights reserved.

 * 

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/skbuff.h>

#include <linux/timer.h>

#include "connector.h"

static struct cb_id cn_test_id = { 0x123, 0x456 };

static char cn_test_name[] = "cn_test";

static struct sock *nls;

static struct timer_list cn_test_timer;

void cn_test_callback(void *data)

{

	struct cn_msg *msg = (struct cn_msg *)data;

	printk("%s: %lu: idx=%x, val=%x, seq=%u, ack=%u, len=%d: %s.\n",

	       __func__, jiffies, msg->id.idx, msg->id.val,

	       msg->seq, msg->ack, msg->len, (char *)msg->data);

}

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", ctl->group);

	return 0;

nlmsg_failure:

	printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack);

	kfree_skb(skb);

	return -EINVAL;

}

static u32 cn_test_timer_counter;

static void cn_test_timer_func(unsigned long __data)

{

	struct cn_msg *m;

	char data[32];

	m = kmalloc(sizeof(*m) + sizeof(data), GFP_ATOMIC);

	if (m) {

		memset(m, 0, sizeof(*m) + sizeof(data));

		memcpy(&m->id, &cn_test_id, sizeof(m->id));

		m->seq = cn_test_timer_counter;

		m->len = sizeof(data);

		m->len =

		    scnprintf(data, sizeof(data), "counter = %u",

			      cn_test_timer_counter) + 1;

		memcpy(m + 1, data, m->len);

		cn_netlink_send(m, 0, gfp_any());

		kfree(m);

	}

	cn_test_timer_counter++;

	mod_timer(&cn_test_timer, jiffies + HZ);

}

static int cn_test_init(void)

{

	int err;

	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;

	}

	init_timer(&cn_test_timer);

	cn_test_timer.function = cn_test_timer_func;

	cn_test_timer.expires = jiffies + HZ;

	cn_test_timer.data = 0;

	add_timer(&cn_test_timer);

	return 0;

      err_out:

	if (nls && nls->sk_socket)

		sock_release(nls->sk_socket);

	return err;

}

static void cn_test_fini(void)

{

	del_timer_sync(&cn_test_timer);

	cn_del_callback(&cn_test_id);

	cn_test_id.val--;

	cn_del_callback(&cn_test_id);

	if (nls && nls->sk_socket)

		sock_release(nls->sk_socket);

}

module_init(cn_test_init);

module_exit(cn_test_fini);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");

MODULE_DESCRIPTION("Connector's test module");

/*****************************************/

Kernel Connector.

/*****************************************/

Kernel connector - new netlink based userspace <-> kernel space easy

to use communication module.

Connector driver adds possibility to connect various agents using

netlink based network.  One must register callback and

identifier. When driver receives special netlink message with

appropriate identifier, appropriate callback will be called.

From the userspace point of view it's quite straightforward:

	socket();

	bind();

	send();

	recv();

But if kernelspace want to use full power of such connections, driver

writer must create special sockets, must know about struct sk_buff

handling...  Connector allows any kernelspace agents to use netlink

based networking for inter-process communication in a significantly

easier way:

int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *));

void cn_netlink_send(struct cn_msg *msg, u32 __group, int gfp_mask);

struct cb_id

{

	__u32			idx;

	__u32			val;

};

idx and val are unique identifiers which must be registered in

connector.h for in-kernel usage.  void (*callback) (void *) - is a

callback function which will be called when message with above idx.val

will be received by connector core.  Argument for that function must

be dereferenced to struct cn_msg *.

struct cn_msg

{

	struct cb_id 		id;

	__u32			seq;

	__u32			ack;

	__u32			len;		/* Length of the following data */

	__u8			data[0];

};

/*****************************************/

Connector interfaces.

/*****************************************/

int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *));

Registers new callback with connector core.

struct cb_id *id 		- unique connector's user identifier.

			  	  It must be registered in connector.h for legal in-kernel users.

char *name 			- connector's callback symbolic name.

void (*callback) (void *)	- connector's callback.

				  Argument must be dereferenced to struct cn_msg *.

void cn_del_callback(struct cb_id *id);

Unregisters new callback with connector core.

struct cb_id *id 		- unique connector's user identifier.

void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask);

Sends message to the specified groups.  It can be safely called from

any context, but may silently fail under strong memory pressure.

struct cn_msg *			- message header(with attached data).

u32 __group			- destination group.

				  If __group is zero, then appropriate group will

				  be searched through all registered connector users,

				  and message will be delivered to the group which was

				  created for user with the same ID as in msg.

				  If __group is not zero, then message will be delivered

				  to the specified group.

int gfp_mask			- GFP mask.

Note: When registering new callback user, connector core assigns

netlink group to the user which is equal to it's id.idx.

/*****************************************/

Protocol description.

/*****************************************/

Current offers transport layer with fixed header.  Recommended

protocol which uses 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.

connector 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}).

As example of usage Documentation/connector now contains cn_test.c -

testing module which uses connector to request notification and to

send messages.

/*****************************************/

Reliability.

/*****************************************/

Netlink itself is not reliable protocol, that means that messages can

be lost due to memory pressure or process' receiving queue overflowed,

so caller is warned must be prepared. That is why struct cn_msg [main

connector's message header] contains u32 seq and u32 ack fields.

source "drivers/base/Kconfig"

source "drivers/base/Kconfig"

source "drivers/connector/Kconfig"

source "drivers/mtd/Kconfig"

source "drivers/mtd/Kconfig"

source "drivers/parport/Kconfig"

source "drivers/parport/Kconfig"

# default.

# default.

obj-y				+= char/

obj-y				+= char/

obj-$(CONFIG_CONNECTOR)		+= connector/

# i810fb and intelfb depend on char/agp/

# i810fb and intelfb depend on char/agp/

obj-$(CONFIG_FB_I810)           += video/i810/

obj-$(CONFIG_FB_I810)           += video/i810/

obj-$(CONFIG_FB_INTEL)          += video/intelfb/

obj-$(CONFIG_FB_INTEL)          += video/intelfb/

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 cn.ko.

endmenu