linux-imx

/*

 * Linux WiMAX

 * Generic messaging interface between userspace and driver/device

 *

 *

 * Copyright (C) 2007-2008 Intel Corporation <linux-wimax@intel.com>

 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>

 *

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

 * modify it under the terms of the GNU General Public License version

 * 2 as published by the Free Software Foundation.

 *

 * 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., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 *

 *

 * This implements a direct communication channel between user space and

 * the driver/device, by which free form messages can be sent back and

 * forth.

 *

 * This is intended for device-specific features, vendor quirks, etc.

 *

 * See include/net/wimax.h

 *

 * GENERIC NETLINK ENCODING AND CAPACITY

 *

 * A destination "pipe name" is added to each message; it is up to the

 * drivers to assign or use those names (if using them at all).

 *

 * Messages are encoded as a binary netlink attribute using nla_put()

 * using type NLA_UNSPEC (as some versions of libnl still in

 * deployment don't yet understand NLA_BINARY).

 *

 * The maximum capacity of this transport is PAGESIZE per message (so

 * the actual payload will be bit smaller depending on the

 * netlink/generic netlink attributes and headers).

 *

 * RECEPTION OF MESSAGES

 *

 * When a message is received from user space, it is passed verbatim

 * to the driver calling wimax_dev->op_msg_from_user(). The return

 * value from this function is passed back to user space as an ack

 * over the generic netlink protocol.

 *

 * The stack doesn't do any processing or interpretation of these

 * messages.

 *

 * SENDING MESSAGES

 *

 * Messages can be sent with wimax_msg().

 *

 * If the message delivery needs to happen on a different context to

 * that of its creation, wimax_msg_alloc() can be used to get a

 * pointer to the message that can be delivered later on with

 * wimax_msg_send().

 *

 * ROADMAP

 *

 * wimax_gnl_doit_msg_from_user()    Process a message from user space

 *   wimax_dev_get_by_genl_info()

 *   wimax_dev->op_msg_from_user()   Delivery of message to the driver

 *

 * wimax_msg()                       Send a message to user space

 *   wimax_msg_alloc()

 *   wimax_msg_send()

 */

#include <linux/device.h>

#include <linux/slab.h>

#include <net/genetlink.h>

#include <linux/netdevice.h>

#include <linux/wimax.h>

#include <linux/security.h>

#include <linux/export.h>

#include "wimax-internal.h"

​

​

#define D_SUBMODULE op_msg

#include "debug-levels.h"

​

​

/**

 * wimax_msg_alloc - Create a new skb for sending a message to userspace

 *

 * @wimax_dev: WiMAX device descriptor

 * @pipe_name: "named pipe" the message will be sent to