/*
 * This file implement the Wireless Extensions APIs.
 *
 * Authors :	Jean Tourrilhes - HPL - <jt@hpl.hp.com>
 * Copyright (c) 1997-2007 Jean Tourrilhes, All Rights Reserved.
 *
 * (As all part of the Linux kernel, this file is GPL)
 */

/************************** DOCUMENTATION **************************/
/*
 * API definition :
 * --------------
 * See <linux/wireless.h> for details of the APIs and the rest.
 *
 * History :
 * -------
 *
 * v1 - 5.12.01 - Jean II
 *	o Created this file.
 *
 * v2 - 13.12.01 - Jean II
 *	o Move /proc/net/wireless stuff from net/core/dev.c to here
 *	o Make Wireless Extension IOCTLs go through here
 *	o Added iw_handler handling ;-)
 *	o Added standard ioctl description
 *	o Initial dumb commit strategy based on orinoco.c
 *
 * v3 - 19.12.01 - Jean II
 *	o Make sure we don't go out of standard_ioctl[] in ioctl_standard_call
 *	o Add event dispatcher function
 *	o Add event description
 *	o Propagate events as rtnetlink IFLA_WIRELESS option
 *	o Generate event on selected SET requests
 *
 * v4 - 18.04.02 - Jean II
 *	o Fix stupid off by one in iw_ioctl_description : IW_ESSID_MAX_SIZE + 1
 *
 * v5 - 21.06.02 - Jean II
 *	o Add IW_PRIV_TYPE_ADDR in priv_type_size (+cleanup)
 *	o Reshuffle IW_HEADER_TYPE_XXX to map IW_PRIV_TYPE_XXX changes
 *	o Add IWEVCUSTOM for driver specific event/scanning token
 *	o Turn on WE_STRICT_WRITE by default + kernel warning
 *	o Fix WE_STRICT_WRITE in ioctl_export_private() (32 => iw_num)
 *	o Fix off-by-one in test (extra_size <= IFNAMSIZ)
 *
 * v6 - 9.01.03 - Jean II
 *	o Add common spy support : iw_handler_set_spy(), wireless_spy_update()
 *	o Add enhanced spy support : iw_handler_set_thrspy() and event.
 *	o Add WIRELESS_EXT version display in /proc/net/wireless
 *
 * v6 - 18.06.04 - Jean II
 *	o Change get_spydata() method for added safety
 *	o Remove spy #ifdef, they are always on -> cleaner code
 *	o Allow any size GET request if user specifies length > max
 *		and if request has IW_DESCR_FLAG_NOMAX flag or is SIOCGIWPRIV
 *	o Start migrating get_wireless_stats to struct iw_handler_def
 *	o Add wmb() in iw_handler_set_spy() for non-coherent archs/cpus
 * Based on patch from Pavel Roskin <proski@gnu.org> :
 *	o Fix kernel data leak to user space in private handler handling
 *
 * v7 - 18.3.05 - Jean II
 *	o Remove (struct iw_point *)->pointer from events and streams
 *	o Remove spy_offset from struct iw_handler_def
 *	o Start deprecating dev->get_wireless_stats, output a warning
 *	o If IW_QUAL_DBM is set, show dBm values in /proc/net/wireless
 *	o Don't lose INVALID/DBM flags when clearing UPDATED flags (iwstats)
 *
 * v8 - 17.02.06 - Jean II
 *	o RtNetlink requests support (SET/GET)
 *
 * v8b - 03.08.06 - Herbert Xu
 *	o Fix Wireless Event locking issues.
 *
 * v9 - 14.3.06 - Jean II
 *	o Change length in ESSID and NICK to strlen() instead of strlen()+1
 *	o Make standard_ioctl_num and standard_event_num unsigned
 *	o Remove (struct net_device *)->get_wireless_stats()
 *
 * v10 - 16.3.07 - Jean II
 *	o Prevent leaking of kernel space in stream on 64 bits.
 */

/***************************** INCLUDES *****************************/

#include <linux/module.h>
#include <linux/types.h>		/* off_t */
#include <linux/netdevice.h>		/* struct ifreq, dev_get_by_name() */
#include <linux/proc_fs.h>
#include <linux/rtnetlink.h>		/* rtnetlink stuff */
#include <linux/seq_file.h>
#include <linux/init.h>			/* for __init */
#include <linux/if_arp.h>		/* ARPHRD_ETHER */
#include <linux/etherdevice.h>		/* compare_ether_addr */
#include <linux/interrupt.h>
#include <net/net_namespace.h>

#include <linux/wireless.h>		/* Pretty obvious */
#include <net/iw_handler.h>		/* New driver API */
#include <net/netlink.h>
#include <net/wext.h>

#include <asm/uaccess.h>		/* copy_to_user() */

/************************* GLOBAL VARIABLES *************************/
/*
 * You should not use global variables, because of re-entrancy.
 * On our case, it's only const, so it's OK...
 */
/*
 * Meta-data about all the standard Wireless Extension request we
 * know about.
 */
static const struct iw_ioctl_description standard_ioctl[] = {
	[SIOCSIWCOMMIT	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_NULL,
	},
	[SIOCGIWNAME	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_CHAR,
		.flags		= IW_DESCR_FLAG_DUMP,
	},
	[SIOCSIWNWID	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
		.flags		= IW_DESCR_FLAG_EVENT,
	},
	[SIOCGIWNWID	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
		.flags		= IW_DESCR_FLAG_DUMP,
	},
	[SIOCSIWFREQ	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_FREQ,
		.flags		= IW_DESCR_FLAG_EVENT,
	},
	[SIOCGIWFREQ	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_FREQ,
		.flags		= IW_DESCR_FLAG_DUMP,
	},
	[SIOCSIWMODE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_UINT,
		.flags		= IW_DESCR_FLAG_EVENT,
	},
	[SIOCGIWMODE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_UINT,
		.flags		= IW_DESCR_FLAG_DUMP,
	},
	[SIOCSIWSENS	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCGIWSENS	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCSIWRANGE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_NULL,
	},
	[SIOCGIWRANGE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= sizeof(struct iw_range),
		.flags		= IW_DESCR_FLAG_DUMP,
	},
	[SIOCSIWPRIV	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_NULL,
	},
	[SIOCGIWPRIV	- SIOCIWFIRST] = { /* (handled directly by us) */
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= sizeof(struct iw_priv_args),
		.max_tokens	= 16,
		.flags		= IW_DESCR_FLAG_NOMAX,
	},
	[SIOCSIWSTATS	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_NULL,
	},
	[SIOCGIWSTATS	- SIOCIWFIRST] = { /* (handled directly by us) */
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= sizeof(struct iw_statistics),
		.flags		= IW_DESCR_FLAG_DUMP,
	},
	[SIOCSIWSPY	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= sizeof(struct sockaddr),
		.max_tokens	= IW_MAX_SPY,
	},
	[SIOCGIWSPY	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= sizeof(struct sockaddr) +
				  sizeof(struct iw_quality),
		.max_tokens	= IW_MAX_SPY,
	},
	[SIOCSIWTHRSPY	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= sizeof(struct iw_thrspy),
		.min_tokens	= 1,
		.max_tokens	= 1,
	},
	[SIOCGIWTHRSPY	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= sizeof(struct iw_thrspy),
		.min_tokens	= 1,
		.max_tokens	= 1,
	},
	[SIOCSIWAP	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_ADDR,
	},
	[SIOCGIWAP	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_ADDR,
		.flags		= IW_DESCR_FLAG_DUMP,
	},
	[SIOCSIWMLME	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.min_tokens	= sizeof(struct iw_mlme),
		.max_tokens	= sizeof(struct iw_mlme),
	},
	[SIOCGIWAPLIST	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= sizeof(struct sockaddr) +
				  sizeof(struct iw_quality),
		.max_tokens	= IW_MAX_AP,
		.flags		= IW_DESCR_FLAG_NOMAX,
	},
	[SIOCSIWSCAN	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.min_tokens	= 0,
		.max_tokens	= sizeof(struct iw_scan_req),
	},
	[SIOCGIWSCAN	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_SCAN_MAX_DATA,
		.flags		= IW_DESCR_FLAG_NOMAX,
	},
	[SIOCSIWESSID	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_ESSID_MAX_SIZE,
		.flags		= IW_DESCR_FLAG_EVENT,
	},
	[SIOCGIWESSID	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_ESSID_MAX_SIZE,
		.flags		= IW_DESCR_FLAG_DUMP,
	},
	[SIOCSIWNICKN	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_ESSID_MAX_SIZE,
	},
	[SIOCGIWNICKN	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_ESSID_MAX_SIZE,
	},
	[SIOCSIWRATE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCGIWRATE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCSIWRTS	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCGIWRTS	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCSIWFRAG	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCGIWFRAG	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCSIWTXPOW	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCGIWTXPOW	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCSIWRETRY	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCGIWRETRY	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCSIWENCODE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_ENCODING_TOKEN_MAX,
		.flags		= IW_DESCR_FLAG_EVENT | IW_DESCR_FLAG_RESTRICT,
	},
	[SIOCGIWENCODE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_ENCODING_TOKEN_MAX,
		.flags		= IW_DESCR_FLAG_DUMP | IW_DESCR_FLAG_RESTRICT,
	},
	[SIOCSIWPOWER	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCGIWPOWER	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCSIWGENIE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_GENERIC_IE_MAX,
	},
	[SIOCGIWGENIE	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_GENERIC_IE_MAX,
	},
	[SIOCSIWAUTH	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCGIWAUTH	- SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_PARAM,
	},
	[SIOCSIWENCODEEXT - SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.min_tokens	= sizeof(struct iw_encode_ext),
		.max_tokens	= sizeof(struct iw_encode_ext) +
				  IW_ENCODING_TOKEN_MAX,
	},
	[SIOCGIWENCODEEXT - SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.min_tokens	= sizeof(struct iw_encode_ext),
		.max_tokens	= sizeof(struct iw_encode_ext) +
				  IW_ENCODING_TOKEN_MAX,
	},
	[SIOCSIWPMKSA - SIOCIWFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.min_tokens	= sizeof(struct iw_pmksa),
		.max_tokens	= sizeof(struct iw_pmksa),
	},
};
static const unsigned standard_ioctl_num = ARRAY_SIZE(standard_ioctl);

/*
 * Meta-data about all the additional standard Wireless Extension events
 * we know about.
 */
static const struct iw_ioctl_description standard_event[] = {
	[IWEVTXDROP	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_ADDR,
	},
	[IWEVQUAL	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_QUAL,
	},
	[IWEVCUSTOM	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_CUSTOM_MAX,
	},
	[IWEVREGISTERED	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_ADDR,
	},
	[IWEVEXPIRED	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_ADDR,
	},
	[IWEVGENIE	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_GENERIC_IE_MAX,
	},
	[IWEVMICHAELMICFAILURE	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= sizeof(struct iw_michaelmicfailure),
	},
	[IWEVASSOCREQIE	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_GENERIC_IE_MAX,
	},
	[IWEVASSOCRESPIE	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= IW_GENERIC_IE_MAX,
	},
	[IWEVPMKIDCAND	- IWEVFIRST] = {
		.header_type	= IW_HEADER_TYPE_POINT,
		.token_size	= 1,
		.max_tokens	= sizeof(struct iw_pmkid_cand),
	},
};
static const unsigned standard_event_num = ARRAY_SIZE(standard_event);

/* Size (in bytes) of the various private data types */
static const char iw_priv_type_size[] = {
	0,				/* IW_PRIV_TYPE_NONE */
	1,				/* IW_PRIV_TYPE_BYTE */
	1,				/* IW_PRIV_TYPE_CHAR */
	0,				/* Not defined */
	sizeof(__u32),			/* IW_PRIV_TYPE_INT */
	sizeof(struct iw_freq),		/* IW_PRIV_TYPE_FLOAT */
	sizeof(struct sockaddr),	/* IW_PRIV_TYPE_ADDR */
	0,				/* Not defined */
};

/* Size (in bytes) of various events */
static const int event_type_size[] = {
	IW_EV_LCP_LEN,			/* IW_HEADER_TYPE_NULL */
	0,
	IW_EV_CHAR_LEN,			/* IW_HEADER_TYPE_CHAR */
	0,
	IW_EV_UINT_LEN,			/* IW_HEADER_TYPE_UINT */
	IW_EV_FREQ_LEN,			/* IW_HEADER_TYPE_FREQ */
	IW_EV_ADDR_LEN,			/* IW_HEADER_TYPE_ADDR */
	0,
	IW_EV_POINT_LEN,		/* Without variable payload */
	IW_EV_PARAM_LEN,		/* IW_HEADER_TYPE_PARAM */
	IW_EV_QUAL_LEN,			/* IW_HEADER_TYPE_QUAL */
};


/************************ COMMON SUBROUTINES ************************/
/*
 * Stuff that may be used in various place or doesn't fit in one
 * of the section below.
 */

/* ---------------------------------------------------------------- */
/*
 * Return the driver handler associated with a specific Wireless Extension.
 */
static iw_handler get_handler(struct net_device *dev, unsigned int cmd)
{
	/* Don't "optimise" the following variable, it will crash */
	unsigned int	index;		/* *MUST* be unsigned */

	/* Check if we have some wireless handlers defined */
	if (dev->wireless_handlers == NULL)
		return NULL;

	/* Try as a standard command */
	index = cmd - SIOCIWFIRST;
	if (index < dev->wireless_handlers->num_standard)
		return dev->wireless_handlers->standard[index];

	/* Try as a private command */
	index = cmd - SIOCIWFIRSTPRIV;
	if (index < dev->wireless_handlers->num_private)
		return dev->wireless_handlers->private[index];

	/* Not found */
	return NULL;
}

/* ---------------------------------------------------------------- */
/*
 * Get statistics out of the driver
 */
static struct iw_statistics *get_wireless_stats(struct net_device *dev)
{
	/* New location */
	if ((dev->wireless_handlers != NULL) &&
	   (dev->wireless_handlers->get_wireless_stats != NULL))
		return dev->wireless_handlers->get_wireless_stats(dev);

	/* Not found */
	return NULL;
}

/* ---------------------------------------------------------------- */
/*
 * Call the commit handler in the driver
 * (if exist and if conditions are right)
 *
 * Note : our current commit strategy is currently pretty dumb,
 * but we will be able to improve on that...
 * The goal is to try to agreagate as many changes as possible
 * before doing the commit. Drivers that will define a commit handler
 * are usually those that need a reset after changing parameters, so
 * we want to minimise the number of reset.
 * A cool idea is to use a timer : at each "set" command, we re-set the
 * timer, when the timer eventually fires, we call the driver.
 * Hopefully, more on that later.
 *
 * Also, I'm waiting to see how many people will complain about the
 * netif_running(dev) test. I'm open on that one...
 * Hopefully, the driver will remember to do a commit in "open()" ;-)
 */
static int call_commit_handler(struct net_device *dev)
{
	if ((netif_running(dev)) &&
	   (dev->wireless_handlers->standard[0] != NULL))
		/* Call the commit handler on the driver */
		return dev->wireless_handlers->standard[0](dev, NULL,
							   NULL, NULL);
	else
		return 0;		/* Command completed successfully */
}

/* ---------------------------------------------------------------- */
/*
 * Calculate size of private arguments
 */
static int get_priv_size(__u16 args)
{
	int	num = args & IW_PRIV_SIZE_MASK;
	int	type = (args & IW_PRIV_TYPE_MASK) >> 12;

	return num * iw_priv_type_size[type];
}

/* ---------------------------------------------------------------- */
/*
 * Re-calculate the size of private arguments
 */
static int adjust_priv_size(__u16 args, struct iw_point *iwp)
{
	int	num = iwp->length;
	int	max = args & IW_PRIV_SIZE_MASK;
	int	type = (args & IW_PRIV_TYPE_MASK) >> 12;

	/* Make sure the driver doesn't goof up */
	if (max < num)
		num = max;

	return num * iw_priv_type_size[type];
}

/* ---------------------------------------------------------------- */
/*
 * Standard Wireless Handler : get wireless stats
 *	Allow programatic access to /proc/net/wireless even if /proc
 *	doesn't exist... Also more efficient...
 */
static int iw_handler_get_iwstats(struct net_device *		dev,
				  struct iw_request_info *	info,
				  union iwreq_data *		wrqu,
				  char *			extra)
{
	/* Get stats from the driver */
	struct iw_statistics *stats;

	stats = get_wireless_stats(dev);
	if (stats) {
		/* Copy statistics to extra */
		memcpy(extra, stats, sizeof(struct iw_statistics));
		wrqu->data.length = sizeof(struct iw_statistics);

		/* Check if we need to clear the updated flag */
		if (wrqu->data.flags != 0)
			stats->qual.updated &= ~IW_QUAL_ALL_UPDATED;
		return 0;
	} else
		return -EOPNOTSUPP;
}

/* ---------------------------------------------------------------- */
/*
 * Standard Wireless Handler : get iwpriv definitions
 * Export the driver private handler definition
 * They will be picked up by tools like iwpriv...
 */
static int iw_handler_get_private(struct net_device *		dev,
				  struct iw_request_info *	info,
				  union iwreq_data *		wrqu,
				  char *			extra)
{
	/* Check if the driver has something to export */
	if ((dev->wireless_handlers->num_private_args == 0) ||
	   (dev->wireless_handlers->private_args == NULL))
		return -EOPNOTSUPP;

	/* Check if there is enough buffer up there */
	if (wrqu->data.length < dev->wireless_handlers->num_private_args) {
		/* User space can't know in advance how large the buffer
		 * needs to be. Give it a hint, so that we can support
		 * any size buffer we want somewhat efficiently... */
		wrqu->data.length = dev->wireless_handlers->num_private_args;
		return -E2BIG;
	}

	/* Set the number of available ioctls. */
	wrqu->data.length = dev->wireless_handlers->num_private_args;

	/* Copy structure to the user buffer. */
	memcpy(extra, dev->wireless_handlers->private_args,
	       sizeof(struct iw_priv_args) * wrqu->data.length);

	return 0;
}


/******************** /proc/net/wireless SUPPORT ********************/
/*
 * The /proc/net/wireless file is a human readable user-space interface
 * exporting various wireless specific statistics from the wireless devices.
 * This is the most popular part of the Wireless Extensions ;-)
 *
 * This interface is a pure clone of /proc/net/dev (in net/core/dev.c).
 * The content of the file is basically the content of "struct iw_statistics".
 */

#ifdef CONFIG_PROC_FS

/* ---------------------------------------------------------------- */
/*
 * Print one entry (line) of /proc/net/wireless
 */
static void wireless_seq_printf_stats(struct seq_file *seq,
				      struct net_device *dev)
{
	/* Get stats from the driver */
	struct iw_statistics *stats = get_wireless_stats(dev);

	if (stats) {
		seq_printf(seq, "%6s: %04x  %3d%c  %3d%c  %3d%c  %6d %6d %6d "
				"%6d %6d   %6d\n",
			   dev->name, stats->status, stats->qual.qual,
			   stats->qual.updated & IW_QUAL_QUAL_UPDATED
			   ? '.' : ' ',
			   ((__s32) stats->qual.level) -
			   ((stats->qual.updated & IW_QUAL_DBM) ? 0x100 : 0),
			   stats->qual.updated & IW_QUAL_LEVEL_UPDATED
			   ? '.' : ' ',
			   ((__s32) stats->qual.noise) -
			   ((stats->qual.updated & IW_QUAL_DBM) ? 0x100 : 0),
			   stats->qual.updated & IW_QUAL_NOISE_UPDATED
			   ? '.' : ' ',
			   stats->discard.nwid, stats->discard.code,
			   stats->discard.fragment, stats->discard.retries,
			   stats->discard.misc, stats->miss.beacon);
		stats->qual.updated &= ~IW_QUAL_ALL_UPDATED;
	}
}

/* ---------------------------------------------------------------- */
/*
 * Print info for /proc/net/wireless (print all entries)
 */
static int wireless_dev_seq_show(struct seq_file *seq, void *v)
{
	might_sleep();

	if (v == SEQ_START_TOKEN)
		seq_printf(seq, "Inter-| sta-|   Quality        |   Discarded "
				"packets               | Missed | WE\n"
				" face | tus | link level noise |  nwid  "
				"crypt   frag  retry   misc | beacon | %d\n",
			   WIRELESS_EXT);
	else
		wireless_seq_printf_stats(seq, v);
	return 0;
}

static void *wireless_dev_seq_start(struct seq_file *seq, loff_t *pos)
{
	struct net *net = seq_file_net(seq);
	loff_t off;
	struct net_device *dev;

	rtnl_lock();
	if (!*pos)
		return SEQ_START_TOKEN;

	off = 1;
	for_each_netdev(net, dev)
		if (off++ == *pos)
			return dev;
	return NULL;
}

static void *wireless_dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct net *net = seq_file_net(seq);

	++*pos;

	return v == SEQ_START_TOKEN ?
		first_net_device(net) : next_net_device(v);
}

static void wireless_dev_seq_stop(struct seq_file *seq, void *v)
{
	rtnl_unlock();
}

static const struct seq_operations wireless_seq_ops = {
	.start = wireless_dev_seq_start,
	.next  = wireless_dev_seq_next,
	.stop  = wireless_dev_seq_stop,
	.show  = wireless_dev_seq_show,
};

static int seq_open_wireless(struct inode *inode, struct file *file)
{
	return seq_open_net(inode, file, &wireless_seq_ops,
			    sizeof(struct seq_net_private));
}

static const struct file_operations wireless_seq_fops = {
	.owner	 = THIS_MODULE,
	.open    = seq_open_wireless,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release_net,
};

int wext_proc_init(struct net *net)
{
	/* Create /proc/net/wireless entry */
	if (!proc_net_fops_create(net, "wireless", S_IRUGO, &wireless_seq_fops))
		return -ENOMEM;

	return 0;
}

void wext_proc_exit(struct net *net)
{
	proc_net_remove(net, "wireless");
}
#endif	/* CONFIG_PROC_FS */

/************************** IOCTL SUPPORT **************************/
/*
 * The original user space API to configure all those Wireless Extensions
 * is through IOCTLs.
 * In there, we check if we need to call the new driver API (iw_handler)
 * or just call the driver ioctl handler.
 */

/* ---------------------------------------------------------------- */
static int ioctl_standard_iw_point(struct iw_point *iwp, unsigned int cmd,
				   const struct iw_ioctl_description *descr,
				   iw_handler handler, struct net_device *dev,
				   struct iw_request_info *info)
{
	int err, extra_size, user_length = 0, essid_compat = 0;
	char *extra;

	/* Calculate space needed by arguments. Always allocate
	 * for max space.
	 */
	extra_size = descr->max_tokens * descr->token_size;

	/* Check need for ESSID compatibility for WE < 21 */
	switch (cmd) {
	case SIOCSIWESSID:
	case SIOCGIWESSID:
	case SIOCSIWNICKN:
	case SIOCGIWNICKN:
		if (iwp->length == descr->max_tokens + 1)
			essid_compat = 1;
		else if (IW_IS_SET(cmd) && (iwp->length != 0)) {
			char essid[IW_ESSID_MAX_SIZE + 1];

			err = copy_from_user(essid, iwp->pointer,
					     iwp->length *
					     descr->token_size);
			if (err)
				return -EFAULT;

			if (essid[iwp->length - 1] == '\0')
				essid_compat = 1;
		}
		break;
	default:
		break;
	}

	iwp->length -= essid_compat;

	/* Check what user space is giving us */
	if (IW_IS_SET(cmd)) {
		/* Check NULL pointer */
		if (!iwp->pointer && iwp->length != 0)
			return -EFAULT;
		/* Check if number of token fits within bounds */
		if (iwp->length > descr->max_tokens)
			return -E2BIG;
		if (iwp->length < descr->min_tokens)
			return -EINVAL;
	} else {
		/* Check NULL pointer */
		if (!iwp->pointer)
			return -EFAULT;
		/* Save user space buffer size for checking */
		user_length = iwp->length;

		/* Don't check if user_length > max to allow forward
		 * compatibility. The test user_length < min is
		 * implied by the test at the end.
		 */

		/* Support for very large requests */
		if ((descr->flags & IW_DESCR_FLAG_NOMAX) &&
		    (user_length > descr->max_tokens)) {
			/* Allow userspace to GET more than max so
			 * we can support any size GET requests.
			 * There is still a limit : -ENOMEM.
			 */
			extra_size = user_length * descr->token_size;

			/* Note : user_length is originally a __u16,
			 * and token_size is controlled by us,
			 * so extra_size won't get negative and
			 * won't overflow...
			 */
		}
	}

	/* kzalloc() ensures NULL-termination for essid_compat. */
	extra = kzalloc(extra_size, GFP_KERNEL);
	if (!extra)
		return -ENOMEM;

	/* If it is a SET, get all the extra data in here */
	if (IW_IS_SET(cmd) && (iwp->length != 0)) {
		if (copy_from_user(extra, iwp->pointer,
				   iwp->length *
				   descr->token_size)) {
			err = -EFAULT;
			goto out;
		}

		if (cmd == SIOCSIWENCODEEXT) {
			struct iw_encode_ext *ee = (void *) extra;

			if (iwp->length < sizeof(*ee) + ee->key_len)
				return -EFAULT;
		}
	}

	err = handler(dev, info, (union iwreq_data *) iwp, extra);

	iwp->length += essid_compat;

	/* If we have something to return to the user */
	if (!err && IW_IS_GET(cmd)) {
		/* Check if there is enough buffer up there */
		if (user_length < iwp->length) {
			err = -E2BIG;
			goto out;
		}

		if (copy_to_user(iwp->pointer, extra,
				 iwp->length *
				 descr->token_size)) {
			err = -EFAULT;
			goto out;
		}
	}

	/* Generate an event to notify listeners of the change */
	if ((descr->flags & IW_DESCR_FLAG_EVENT) && err == -EIWCOMMIT) {
		union iwreq_data *data = (union iwreq_data *) iwp;

		if (descr->flags & IW_DESCR_FLAG_RESTRICT)
			/* If the event is restricted, don't
			 * export the payload.
			 */
			wireless_send_event(dev, cmd, data, NULL);
		else
			wireless_send_event(dev, cmd, data, extra);
	}

out:
	kfree(extra);
	return err;
}

/*
 * Wrapper to call a standard Wireless Extension handler.
 * We do various checks and also take care of moving data between
 * user space and kernel space.
 */
static int ioctl_standard_call(struct net_device *	dev,
			       struct iwreq		*iwr,
			       unsigned int		cmd,
			       struct iw_request_info	*info,
			       iw_handler		handler)
{
	const struct iw_ioctl_description *	descr;
	int					ret = -EINVAL;

	/* Get the description of the IOCTL */
	if ((cmd - SIOCIWFIRST) >= standard_ioctl_num)
		return -EOPNOTSUPP;
	descr = &(standard_ioctl[cmd - SIOCIWFIRST]);

	/* Check if we have a pointer to user space data or not */
	if (descr->header_type != IW_HEADER_TYPE_POINT) {

		/* No extra arguments. Trivial to handle */
		ret = handler(dev, info, &(iwr->u), NULL);

		/* Generate an event to notify listeners of the change */
		if ((descr->flags & IW_DESCR_FLAG_EVENT) &&
		   ((ret == 0) || (ret == -EIWCOMMIT)))
			wireless_send_event(dev, cmd, &(iwr->u), NULL);
	} else {
		ret = ioctl_standard_iw_point(&iwr->u.data, cmd, descr,
					      handler, dev, info);
	}

	/* Call commit handler if needed and defined */
	if (ret == -EIWCOMMIT)
		ret = call_commit_handler(dev);

	/* Here, we will generate the appropriate event if needed */

	return ret;
}

/* ---------------------------------------------------------------- */
/*
 * Wrapper to call a private Wireless Extension handler.
 * We do various checks and also take care of moving data between
 * user space and kernel space.
 * It's not as nice and slimline as the standard wrapper. The cause
 * is struct iw_priv_args, which was not really designed for the
 * job we are going here.
 *
 * IMPORTANT : This function prevent to set and get data on the same
 * IOCTL and enforce the SET/GET convention. Not doing it would be
 * far too hairy...
 * If you need to set and get data at the same time, please don't use
 * a iw_handler but process it in your ioctl handler (i.e. use the
 * old driver API).
 */
static int get_priv_descr_and_size(struct net_device *dev, unsigned int cmd,
				   const struct iw_priv_args **descrp)
{
	const struct iw_priv_args *descr;
	int i, extra_size;

	descr = NULL;
	for (i = 0; i < dev->wireless_handlers->num_private_args; i++) {
		if (cmd == dev->wireless_handlers->private_args[i].cmd) {
			descr = &dev->wireless_handlers->private_args[i];
			break;
		}
	}

	extra_size = 0;
	if (descr) {
		if (IW_IS_SET(cmd)) {
			int	offset = 0;	/* For sub-ioctls */
			/* Check for sub-ioctl handler */
			if (descr->name[0] == '\0')
				/* Reserve one int for sub-ioctl index */
				offset = sizeof(__u32);

			/* Size of set arguments */
			extra_size = get_priv_size(descr->set_args);

			/* Does it fits in iwr ? */
			if ((descr->set_args & IW_PRIV_SIZE_FIXED) &&
			   ((extra_size + offset) <= IFNAMSIZ))
				extra_size = 0;
		} else {
			/* Size of get arguments */
			extra_size = get_priv_size(descr->get_args);

			/* Does it fits in iwr ? */
			if ((descr->get_args & IW_PRIV_SIZE_FIXED) &&
			   (extra_size <= IFNAMSIZ))
				extra_size = 0;
		}
	}
	*descrp = descr;
	return extra_size;
}

static int ioctl_private_iw_point(struct iw_point *iwp, unsigned int cmd,
				  const struct iw_priv_args *descr,
				  iw_handler handler, struct net_device *dev,
				  struct iw_request_info *info, int extra_size)
{
	char *extra;
	int err;

	/* Check what user space is giving us */
	if (IW_IS_SET(cmd)) {
		if (!iwp->pointer && iwp->length != 0)
			return -EFAULT;

		if (iwp->length > (descr->set_args & IW_PRIV_SIZE_MASK))
			return -E2BIG;
	} else if (!iwp->pointer)
		return -EFAULT;

	extra = kmalloc(extra_size, GFP_KERNEL);
	if (!extra)
		return -ENOMEM;

	/* If it is a SET, get all the extra data in here */
	if (IW_IS_SET(cmd) && (iwp->length != 0)) {
		if (copy_from_user(extra, iwp->pointer, extra_size)) {
			err = -EFAULT;
			goto out;
		}
	}

	/* Call the handler */
	err = handler(dev, info, (union iwreq_data *) iwp, extra);

	/* If we have something to return to the user */
	if (!err && IW_IS_GET(cmd)) {
		/* Adjust for the actual length if it's variable,
		 * avoid leaking kernel bits outside.
		 */
		if (!(descr->get_args & IW_PRIV_SIZE_FIXED))
			extra_size = adjust_priv_size(descr->get_args, iwp);

		if (copy_to_user(iwp->pointer, extra, extra_size))
			err =  -EFAULT;
	}

out:
	kfree(extra);
	return err;
}

static int ioctl_private_call(struct net_device *dev, struct iwreq *iwr,
			      unsigned int cmd, struct iw_request_info *info,
			      iw_handler handler)
{
	int extra_size = 0, ret = -EINVAL;
	const struct iw_priv_args *descr;

	extra_size = get_priv_descr_and_size(dev, cmd, &descr);

	/* Check if we have a pointer to user space data or not. */
	if (extra_size == 0) {
		/* No extra arguments. Trivial to handle */
		ret = handler(dev, info, &(iwr->u), (char *) &(iwr->u));
	} else {
		ret = ioctl_private_iw_point(&iwr->u.data, cmd, descr,
					     handler, dev, info, extra_size);
	}

	/* Call commit handler if needed and defined */
	if (ret == -EIWCOMMIT)
		ret = call_commit_handler(dev);

	return ret;
}

/* ---------------------------------------------------------------- */
typedef int (*wext_ioctl_func)(struct net_device *, struct iwreq *,
			       unsigned int, struct iw_request_info *,
			       iw_handler);

/*
 * Main IOCTl dispatcher.
 * Check the type of IOCTL and call the appropriate wrapper...
 */
static int wireless_process_ioctl(struct net *net, struct ifreq *ifr,
				  unsigned int cmd,
				  struct iw_request_info *info,
				  wext_ioctl_func standard,
				  wext_ioctl_func private)
{
	struct iwreq *iwr = (struct iwreq *) ifr;
	struct net_device *dev;
	iw_handler	handler;

	/* Permissions are already checked in dev_ioctl() before calling us.
	 * The copy_to/from_user() of ifr is also dealt with in there */

	/* Make sure the device exist */
	if ((dev = __dev_get_by_name(net, ifr->ifr_name)) == NULL)
		return -ENODEV;

	/* A bunch of special cases, then the generic case...
	 * Note that 'cmd' is already filtered in dev_ioctl() with
	 * (cmd >= SIOCIWFIRST && cmd <= SIOCIWLAST) */
	if (cmd == SIOCGIWSTATS)
		return standard(dev, iwr, cmd, info,
				&iw_handler_get_iwstats);

	if (cmd == SIOCGIWPRIV && dev->wireless_handlers)
		return standard(dev, iwr, cmd, info,
				&iw_handler_get_private);

	/* Basic check */
	if (!netif_device_present(dev))
		return -ENODEV;

	/* New driver API : try to find the handler */
	handler = get_handler(dev, cmd);
	if (handler) {
		/* Standard and private are not the same */
		if (cmd < SIOCIWFIRSTPRIV)
			return standard(dev, iwr, cmd, info, handler);
		else
			return private(dev, iwr, cmd, info, handler);
	}
	/* Old driver API : call driver ioctl handler */
	if (dev->netdev_ops->ndo_do_ioctl)
		return dev->netdev_ops->ndo_do_ioctl(dev, ifr, cmd);
	return -EOPNOTSUPP;
}

/* If command is `set a parameter', or `get the encoding parameters',
 * check if the user has the right to do it.
 */
static int wext_permission_check(unsigned int cmd)
{
	if ((IW_IS_SET(cmd) || cmd == SIOCGIWENCODE || cmd == SIOCGIWENCODEEXT)
	    && !capable(CAP_NET_ADMIN))
		return -EPERM;

	return 0;
}

/* entry point from dev ioctl */
static int wext_ioctl_dispatch(struct net *net, struct ifreq *ifr,
			       unsigned int cmd, struct iw_request_info *info,
			       wext_ioctl_func standard,
			       wext_ioctl_func private)
{
	int ret = wext_permission_check(cmd);

	if (ret)
		return ret;

	dev_load(net, ifr->ifr_name);
	rtnl_lock();
	ret = wireless_process_ioctl(net, ifr, cmd, info, standard, private);
	rtnl_unlock();

	return ret;
}

int wext_handle_ioctl(struct net *net, struct ifreq *ifr, unsigned int cmd,
		      void __user *arg)
{
	struct iw_request_info info = { .cmd = cmd, .flags = 0 };
	int ret;

	ret = wext_ioctl_dispatch(net, ifr, cmd, &info,
				  ioctl_standard_call,
				  ioctl_private_call);
	if (ret >= 0 &&
	    IW_IS_GET(cmd) &&
	    copy_to_user(arg, ifr, sizeof(struct iwreq)))
		return -EFAULT;

	return ret;
}

#ifdef CONFIG_COMPAT
static int compat_standard_call(struct net_device	*dev,
				struct iwreq		*iwr,
				unsigned int		cmd,
				struct iw_request_info	*info,
				iw_handler		handler)
{
	const struct iw_ioctl_description *descr;
	struct compat_iw_point *iwp_compat;
	struct iw_point iwp;
	int err;

	descr = standard_ioctl + (cmd - SIOCIWFIRST);

	if (descr->header_type != IW_HEADER_TYPE_POINT)
		return ioctl_standard_call(dev, iwr, cmd, info, handler);

	iwp_compat = (struct compat_iw_point *) &iwr->u.data;
	iwp.pointer = compat_ptr(iwp_compat->pointer);
	iwp.length = iwp_compat->length;
	iwp.flags = iwp_compat->flags;

	err = ioctl_standard_iw_point(&iwp, cmd, descr, handler, dev, info);

	iwp_compat->pointer = ptr_to_compat(iwp.pointer);
	iwp_compat->length = iwp.length;
	iwp_compat->flags = iwp.flags;

	return err;
}

static int compat_private_call(struct net_device *dev, struct iwreq *iwr,
			       unsigned int cmd, struct iw_request_info *info,
			       iw_handler handler)
{
	const struct iw_priv_args *descr;
	int ret, extra_size;

	extra_size = get_priv_descr_and_size(dev, cmd, &descr);

	/* Check if we have a pointer to user space data or not. */
	if (extra_size == 0) {
		/* No extra arguments. Trivial to handle */
		ret = handler(dev, info, &(iwr->u), (char *) &(iwr->u));
	} else {
		struct compat_iw_point *iwp_compat;
		struct iw_point iwp;

		iwp_compat = (struct compat_iw_point *) &iwr->u.data;
		iwp.pointer = compat_ptr(iwp_compat->pointer);
		iwp.length = iwp_compat->length;
		iwp.flags = iwp_compat->flags;

		ret = ioctl_private_iw_point(&iwp, cmd, descr,
					     handler, dev, info, extra_size);

		iwp_compat->pointer = ptr_to_compat(iwp.pointer);
		iwp_compat->length = iwp.length;
		iwp_compat->flags = iwp.flags;
	}

	/* Call commit handler if needed and defined */
	if (ret == -EIWCOMMIT)
		ret = call_commit_handler(dev);

	return ret;
}

int compat_wext_handle_ioctl(struct net *net, unsigned int cmd,
			     unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	struct iw_request_info info;
	struct iwreq iwr;
	char *colon;
	int ret;

	if (copy_from_user(&iwr, argp, sizeof(struct iwreq)))
		return -EFAULT;

	iwr.ifr_name[IFNAMSIZ-1] = 0;
	colon = strchr(iwr.ifr_name, ':');
	if (colon)
		*colon = 0;

	info.cmd = cmd;
	info.flags = IW_REQUEST_FLAG_COMPAT;

	ret = wext_ioctl_dispatch(net, (struct ifreq *) &iwr, cmd, &info,
				  compat_standard_call,
				  compat_private_call);

	if (ret >= 0 &&
	    IW_IS_GET(cmd) &&
	    copy_to_user(argp, &iwr, sizeof(struct iwreq)))
		return -EFAULT;

	return ret;
}
#endif

/************************* EVENT PROCESSING *************************/
/*
 * Process events generated by the wireless layer or the driver.
 * Most often, the event will be propagated through rtnetlink
 */

/* ---------------------------------------------------------------- */
/*
 * Locking...
 * ----------
 *
 * Thanks to Herbert Xu <herbert@gondor.apana.org.au> for fixing
 * the locking issue in here and implementing this code !
 *
 * The issue : wireless_send_event() is often called in interrupt context,
 * while the Netlink layer can never be called in interrupt context.
 * The fully formed RtNetlink events are queued, and then a tasklet is run
 * to feed those to Netlink.
 * The skb_queue is interrupt safe, and its lock is not held while calling
 * Netlink, so there is no possibility of dealock.
 * Jean II
 */

static struct sk_buff_head wireless_nlevent_queue;

static int __init wireless_nlevent_init(void)
{
	skb_queue_head_init(&wireless_nlevent_queue);
	return 0;
}

subsys_initcall(wireless_nlevent_init);

static void wireless_nlevent_process(unsigned long data)
{
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&wireless_nlevent_queue)))
		rtnl_notify(skb, &init_net, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
}

static DECLARE_TASKLET(wireless_nlevent_tasklet, wireless_nlevent_process, 0);

/* ---------------------------------------------------------------- */
/*
 * Fill a rtnetlink message with our event data.
 * Note that we propage only the specified event and don't dump the
 * current wireless config. Dumping the wireless config is far too
 * expensive (for each parameter, the driver need to query the hardware).
 */
static int rtnetlink_fill_iwinfo(struct sk_buff *skb, struct net_device *dev,
				 int type, char *event, int event_len)
{
	struct ifinfomsg *r;
	struct nlmsghdr  *nlh;

	nlh = nlmsg_put(skb, 0, 0, type, sizeof(*r), 0);
	if (nlh == NULL)
		return -EMSGSIZE;

	r = nlmsg_data(nlh);
	r->ifi_family = AF_UNSPEC;
	r->__ifi_pad = 0;
	r->ifi_type = dev->type;
	r->ifi_index = dev->ifindex;
	r->ifi_flags = dev_get_flags(dev);
	r->ifi_change = 0;	/* Wireless changes don't affect those flags */

	NLA_PUT_STRING(skb, IFLA_IFNAME, dev->name);
	/* Add the wireless events in the netlink packet */
	NLA_PUT(skb, IFLA_WIRELESS, event_len, event);

	return nlmsg_end(skb, nlh);

nla_put_failure:
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
}

/* ---------------------------------------------------------------- */
/*
 * Create and broadcast and send it on the standard rtnetlink socket
 * This is a pure clone rtmsg_ifinfo() in net/core/rtnetlink.c
 * Andrzej Krzysztofowicz mandated that I used a IFLA_XXX field
 * within a RTM_NEWLINK event.
 */
static void rtmsg_iwinfo(struct net_device *dev, char *event, int event_len)
{
	struct sk_buff *skb;
	int err;

	if (!net_eq(dev_net(dev), &init_net))
		return;

	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
	if (!skb)
		return;

	err = rtnetlink_fill_iwinfo(skb, dev, RTM_NEWLINK, event, event_len);
	if (err < 0) {
		WARN_ON(err == -EMSGSIZE);
		kfree_skb(skb);
		return;
	}

	NETLINK_CB(skb).dst_group = RTNLGRP_LINK;
	skb_queue_tail(&wireless_nlevent_queue, skb);
	tasklet_schedule(&wireless_nlevent_tasklet);
}

/* ---------------------------------------------------------------- */
/*
 * Main event dispatcher. Called from other parts and drivers.
 * Send the event on the appropriate channels.
 * May be called from interrupt context.
 */
void wireless_send_event(struct net_device *	dev,
			 unsigned int		cmd,
			 union iwreq_data *	wrqu,
			 char *			extra)
{
	const struct iw_ioctl_description *	descr = NULL;
	int extra_len = 0;
	struct iw_event  *event;		/* Mallocated whole event */
	int event_len;				/* Its size */
	int hdr_len;				/* Size of the event header */
	int wrqu_off = 0;			/* Offset in wrqu */
	/* Don't "optimise" the following variable, it will crash */
	unsigned	cmd_index;		/* *MUST* be unsigned */

	/* Get the description of the Event */
	if (cmd <= SIOCIWLAST) {
		cmd_index = cmd - SIOCIWFIRST;
		if (cmd_index < standard_ioctl_num)
			descr = &(standard_ioctl[cmd_index]);
	} else {
		cmd_index = cmd - IWEVFIRST;
		if (cmd_index < standard_event_num)
			descr = &(standard_event[cmd_index]);
	}
	/* Don't accept unknown events */
	if (descr == NULL) {
		/* Note : we don't return an error to the driver, because
		 * the driver would not know what to do about it. It can't
		 * return an error to the user, because the event is not
		 * initiated by a user request.
		 * The best the driver could do is to log an error message.
		 * We will do it ourselves instead...
		 */
		printk(KERN_ERR "%s (WE) : Invalid/Unknown Wireless Event (0x%04X)\n",
		       dev->name, cmd);
		return;
	}

	/* Check extra parameters and set extra_len */
	if (descr->header_type == IW_HEADER_TYPE_POINT) {
		/* Check if number of token fits within bounds */
		if (wrqu->data.length > descr->max_tokens) {
			printk(KERN_ERR "%s (WE) : Wireless Event too big (%d)\n", dev->name, wrqu->data.length);
			return;
		}
		if (wrqu->data.length < descr->min_tokens) {
			printk(KERN_ERR "%s (WE) : Wireless Event too small (%d)\n", dev->name, wrqu->data.length);
			return;
		}
		/* Calculate extra_len - extra is NULL for restricted events */
		if (extra != NULL)
			extra_len = wrqu->data.length * descr->token_size;
		/* Always at an offset in wrqu */
		wrqu_off = IW_EV_POINT_OFF;
	}

	/* Total length of the event */
	hdr_len = event_type_size[descr->header_type];
	event_len = hdr_len + extra_len;

	/* Create temporary buffer to hold the event */
	event = kmalloc(event_len, GFP_ATOMIC);
	if (event == NULL)
		return;

	/* Fill event */
	event->len = event_len;
	event->cmd = cmd;
	memcpy(&event->u, ((char *) wrqu) + wrqu_off, hdr_len - IW_EV_LCP_LEN);
	if (extra)
		memcpy(((char *) event) + hdr_len, extra, extra_len);

	/* Send via the RtNetlink event channel */
	rtmsg_iwinfo(dev, (char *) event, event_len);

	/* Cleanup */
	kfree(event);

	return;		/* Always success, I guess ;-) */
}
EXPORT_SYMBOL(wireless_send_event);

/********************** ENHANCED IWSPY SUPPORT **********************/
/*
 * In the old days, the driver was handling spy support all by itself.
 * Now, the driver can delegate this task to Wireless Extensions.
 * It needs to use those standard spy iw_handler in struct iw_handler_def,
 * push data to us via wireless_spy_update() and include struct iw_spy_data
 * in its private part (and export it in net_device->wireless_data->spy_data).
 * One of the main advantage of centralising spy support here is that
 * it becomes much easier to improve and extend it without having to touch
 * the drivers. One example is the addition of the Spy-Threshold events.
 */

/* ---------------------------------------------------------------- */
/*
 * Return the pointer to the spy data in the driver.
 * Because this is called on the Rx path via wireless_spy_update(),
 * we want it to be efficient...
 */
static inline struct iw_spy_data *get_spydata(struct net_device *dev)
{
	/* This is the new way */
	if (dev->wireless_data)
		return dev->wireless_data->spy_data;
	return NULL;
}

/*------------------------------------------------------------------*/
/*
 * Standard Wireless Handler : set Spy List
 */
int iw_handler_set_spy(struct net_device *	dev,
		       struct iw_request_info *	info,
		       union iwreq_data *	wrqu,
		       char *			extra)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	struct sockaddr *	address = (struct sockaddr *) extra;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return -EOPNOTSUPP;

	/* Disable spy collection while we copy the addresses.
	 * While we copy addresses, any call to wireless_spy_update()
	 * will NOP. This is OK, as anyway the addresses are changing. */
	spydata->spy_number = 0;

	/* We want to operate without locking, because wireless_spy_update()
	 * most likely will happen in the interrupt handler, and therefore
	 * have its own locking constraints and needs performance.
	 * The rtnl_lock() make sure we don't race with the other iw_handlers.
	 * This make sure wireless_spy_update() "see" that the spy list
	 * is temporarily disabled. */
	smp_wmb();

	/* Are there are addresses to copy? */
	if (wrqu->data.length > 0) {
		int i;

		/* Copy addresses */
		for (i = 0; i < wrqu->data.length; i++)
			memcpy(spydata->spy_address[i], address[i].sa_data,
			       ETH_ALEN);
		/* Reset stats */
		memset(spydata->spy_stat, 0,
		       sizeof(struct iw_quality) * IW_MAX_SPY);
	}

	/* Make sure above is updated before re-enabling */
	smp_wmb();

	/* Enable addresses */
	spydata->spy_number = wrqu->data.length;

	return 0;
}
EXPORT_SYMBOL(iw_handler_set_spy);

/*------------------------------------------------------------------*/
/*
 * Standard Wireless Handler : get Spy List
 */
int iw_handler_get_spy(struct net_device *	dev,
		       struct iw_request_info *	info,
		       union iwreq_data *	wrqu,
		       char *			extra)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	struct sockaddr *	address = (struct sockaddr *) extra;
	int			i;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return -EOPNOTSUPP;

	wrqu->data.length = spydata->spy_number;

	/* Copy addresses. */
	for (i = 0; i < spydata->spy_number; i++) 	{
		memcpy(address[i].sa_data, spydata->spy_address[i], ETH_ALEN);
		address[i].sa_family = AF_UNIX;
	}
	/* Copy stats to the user buffer (just after). */
	if (spydata->spy_number > 0)
		memcpy(extra  + (sizeof(struct sockaddr) *spydata->spy_number),
		       spydata->spy_stat,
		       sizeof(struct iw_quality) * spydata->spy_number);
	/* Reset updated flags. */
	for (i = 0; i < spydata->spy_number; i++)
		spydata->spy_stat[i].updated &= ~IW_QUAL_ALL_UPDATED;
	return 0;
}
EXPORT_SYMBOL(iw_handler_get_spy);

/*------------------------------------------------------------------*/
/*
 * Standard Wireless Handler : set spy threshold
 */
int iw_handler_set_thrspy(struct net_device *	dev,
			  struct iw_request_info *info,
			  union iwreq_data *	wrqu,
			  char *		extra)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	struct iw_thrspy *	threshold = (struct iw_thrspy *) extra;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return -EOPNOTSUPP;

	/* Just do it */
	memcpy(&(spydata->spy_thr_low), &(threshold->low),
	       2 * sizeof(struct iw_quality));

	/* Clear flag */
	memset(spydata->spy_thr_under, '\0', sizeof(spydata->spy_thr_under));

	return 0;
}
EXPORT_SYMBOL(iw_handler_set_thrspy);

/*------------------------------------------------------------------*/
/*
 * Standard Wireless Handler : get spy threshold
 */
int iw_handler_get_thrspy(struct net_device *	dev,
			  struct iw_request_info *info,
			  union iwreq_data *	wrqu,
			  char *		extra)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	struct iw_thrspy *	threshold = (struct iw_thrspy *) extra;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return -EOPNOTSUPP;

	/* Just do it */
	memcpy(&(threshold->low), &(spydata->spy_thr_low),
	       2 * sizeof(struct iw_quality));

	return 0;
}
EXPORT_SYMBOL(iw_handler_get_thrspy);

/*------------------------------------------------------------------*/
/*
 * Prepare and send a Spy Threshold event
 */
static void iw_send_thrspy_event(struct net_device *	dev,
				 struct iw_spy_data *	spydata,
				 unsigned char *	address,
				 struct iw_quality *	wstats)
{
	union iwreq_data	wrqu;
	struct iw_thrspy	threshold;

	/* Init */
	wrqu.data.length = 1;
	wrqu.data.flags = 0;
	/* Copy address */
	memcpy(threshold.addr.sa_data, address, ETH_ALEN);
	threshold.addr.sa_family = ARPHRD_ETHER;
	/* Copy stats */
	memcpy(&(threshold.qual), wstats, sizeof(struct iw_quality));
	/* Copy also thresholds */
	memcpy(&(threshold.low), &(spydata->spy_thr_low),
	       2 * sizeof(struct iw_quality));

	/* Send event to user space */
	wireless_send_event(dev, SIOCGIWTHRSPY, &wrqu, (char *) &threshold);
}

/* ---------------------------------------------------------------- */
/*
 * Call for the driver to update the spy data.
 * For now, the spy data is a simple array. As the size of the array is
 * small, this is good enough. If we wanted to support larger number of
 * spy addresses, we should use something more efficient...
 */
void wireless_spy_update(struct net_device *	dev,
			 unsigned char *	address,
			 struct iw_quality *	wstats)
{
	struct iw_spy_data *	spydata = get_spydata(dev);
	int			i;
	int			match = -1;

	/* Make sure driver is not buggy or using the old API */
	if (!spydata)
		return;

	/* Update all records that match */
	for (i = 0; i < spydata->spy_number; i++)
		if (!compare_ether_addr(address, spydata->spy_address[i])) {
			memcpy(&(spydata->spy_stat[i]), wstats,
			       sizeof(struct iw_quality));
			match = i;
		}

	/* Generate an event if we cross the spy threshold.
	 * To avoid event storms, we have a simple hysteresis : we generate
	 * event only when we go under the low threshold or above the
	 * high threshold. */
	if (match >= 0) {
		if (spydata->spy_thr_under[match]) {
			if (wstats->level > spydata->spy_thr_high.level) {
				spydata->spy_thr_under[match] = 0;
				iw_send_thrspy_event(dev, spydata,
						     address, wstats);
			}
		} else {
			if (wstats->level < spydata->spy_thr_low.level) {
				spydata->spy_thr_under[match] = 1;
				iw_send_thrspy_event(dev, spydata,
						     address, wstats);
			}
		}
	}
}
EXPORT_SYMBOL(wireless_spy_update);