/*
 * This file implement the Wireless Extensions spy API.
 *
 * 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)
 */

#include <linux/wireless.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <net/iw_handler.h>
#include <net/arp.h>
#include <net/wext.h>

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;
}

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);

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);