/*
   * 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 <linux/export.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 (ether_addr_equal(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);