splice: fix generic_file_splice_read() race with page invalidation

[linux-2.6/verdex.git] / net / wireless / wext.c

/*
 * 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 loose 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 inline 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 inline int adjust_priv_size(__u16                args,
                                   union iwreq_data *   wrqu)
{
        int     num = wrqu->data.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_seq_show(struct seq_file *seq, void *v)
{
        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 const struct seq_operations wireless_seq_ops = {
        .start = dev_seq_start,
        .next  = dev_seq_next,
        .stop  = dev_seq_stop,
        .show  = wireless_seq_show,
};

static int wireless_seq_open(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    = wireless_seq_open,
        .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.
 */

/* ---------------------------------------------------------------- */
/*
 * 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 ifreq *           ifr,
                               unsigned int             cmd,
                               iw_handler               handler)
{
        struct iwreq *                          iwr = (struct iwreq *) ifr;
        const struct iw_ioctl_description *     descr;
        struct iw_request_info                  info;
        int                                     ret = -EINVAL;

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

        /* Prepare the call */
        info.cmd = cmd;
        info.flags = 0;

        /* 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 {
                char *  extra;
                int     extra_size;
                int     user_length = 0;
                int     err;
                int     essid_compat = 0;

                /* Calculate space needed by arguments. Always allocate
                 * for max space. Easier, and won't last long... */
                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 (iwr->u.data.length == descr->max_tokens + 1)
                                essid_compat = 1;
                        else if (IW_IS_SET(cmd) && (iwr->u.data.length != 0)) {
                                char essid[IW_ESSID_MAX_SIZE + 1];

                                err = copy_from_user(essid, iwr->u.data.pointer,
                                                     iwr->u.data.length *
                                                     descr->token_size);
                                if (err)
                                        return -EFAULT;

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

                iwr->u.data.length -= essid_compat;

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

                /* Create the kernel buffer */
                /*    kzalloc ensures NULL-termination for essid_compat */
                extra = kzalloc(extra_size, GFP_KERNEL);
                if (extra == NULL)
                        return -ENOMEM;

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

                /* Call the handler */
                ret = handler(dev, &info, &(iwr->u), extra);

                iwr->u.data.length += essid_compat;

                /* If we have something to return to the user */
                if (!ret && IW_IS_GET(cmd)) {
                        /* Check if there is enough buffer up there */
                        if (user_length < iwr->u.data.length) {
                                kfree(extra);
                                return -E2BIG;
                        }

                        err = copy_to_user(iwr->u.data.pointer, extra,
                                           iwr->u.data.length *
                                           descr->token_size);
                        if (err)
                                ret =  -EFAULT;
                }

                /* Generate an event to notify listeners of the change */
                if ((descr->flags & IW_DESCR_FLAG_EVENT) &&
                   ((ret == 0) || (ret == -EIWCOMMIT))) {
                        if (descr->flags & IW_DESCR_FLAG_RESTRICT)
                                /* If the event is restricted, don't
                                 * export the payload */
                                wireless_send_event(dev, cmd, &(iwr->u), NULL);
                        else
                                wireless_send_event(dev, cmd, &(iwr->u),
                                                    extra);
                }

                /* Cleanup - I told you it wasn't that long ;-) */
                kfree(extra);
        }

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

        /* Get the description of the IOCTL */
        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;
                }

        /* Compute the size of the set/get arguments */
        if (descr != NULL) {
                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;
                }
        }

        /* Prepare the call */
        info.cmd = cmd;
        info.flags = 0;

        /* 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 {
                char *  extra;
                int     err;

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

                        /* Does it fits within bounds ? */
                        if (iwr->u.data.length > (descr->set_args &
                                                 IW_PRIV_SIZE_MASK))
                                return -E2BIG;
                } else if (iwr->u.data.pointer == NULL)
                        return -EFAULT;

                /* Always allocate for max space. Easier, and won't last
                 * long... */
                extra = kmalloc(extra_size, GFP_KERNEL);
                if (extra == NULL)
                        return -ENOMEM;

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

                /* Call the handler */
                ret = handler(dev, &info, &(iwr->u), extra);

                /* If we have something to return to the user */
                if (!ret && 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,
                                                              &(iwr->u));
                        }

                        err = copy_to_user(iwr->u.data.pointer, extra,
                                           extra_size);
                        if (err)
                                ret =  -EFAULT;
                }

                /* Cleanup - I told you it wasn't that long ;-) */
                kfree(extra);
        }


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

        return ret;
}

/* ---------------------------------------------------------------- */
/*
 * 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 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 ioctl_standard_call(dev, ifr, cmd,
                                           &iw_handler_get_iwstats);

        if (cmd == SIOCGIWPRIV && dev->wireless_handlers)
                return ioctl_standard_call(dev, ifr, cmd,
                                           &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 ioctl_standard_call(dev, ifr, cmd, handler);
                else
                        return ioctl_private_call(dev, ifr, cmd, handler);
        }
        /* Old driver API : call driver ioctl handler */
        if (dev->do_ioctl)
                return dev->do_ioctl(dev, ifr, cmd);
        return -EOPNOTSUPP;
}

/* entry point from dev ioctl */
int wext_handle_ioctl(struct net *net, struct ifreq *ifr, unsigned int cmd,
                      void __user *arg)
{
        int ret;

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

        dev_load(net, ifr->ifr_name);
        rtnl_lock();
        ret = wireless_process_ioctl(net, ifr, cmd);
        rtnl_unlock();
        if (IW_IS_GET(cmd) && copy_to_user(arg, ifr, sizeof(struct iwreq)))
                return -EFAULT;
        return ret;
}

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

        /* 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 (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);