/*
* cfg80211 scan result handling
*
* Copyright 2008 Johannes Berg <johannes@sipsolutions.net>
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/wireless.h>
#include <linux/nl80211.h>
#include <linux/etherdevice.h>
#include <net/arp.h>
#include <net/cfg80211.h>
#include <net/cfg80211-wext.h>
#include <net/iw_handler.h>
#include "core.h"
#include "nl80211.h"
#include "wext-compat.h"
#include "rdev-ops.h"
/**
* DOC: BSS tree/list structure
*
* At the top level, the BSS list is kept in both a list in each
* registered device (@bss_list) as well as an RB-tree for faster
* lookup. In the RB-tree, entries can be looked up using their
* channel, MESHID, MESHCONF (for MBSSes) or channel, BSSID, SSID
* for other BSSes.
*
* Due to the possibility of hidden SSIDs, there's a second level
* structure, the "hidden_list" and "hidden_beacon_bss" pointer.
* The hidden_list connects all BSSes belonging to a single AP
* that has a hidden SSID, and connects beacon and probe response
* entries. For a probe response entry for a hidden SSID, the
* hidden_beacon_bss pointer points to the BSS struct holding the
* beacon's information.
*
* Reference counting is done for all these references except for
* the hidden_list, so that a beacon BSS struct that is otherwise
* not referenced has one reference for being on the bss_list and
* one for each probe response entry that points to it using the
* hidden_beacon_bss pointer. When a BSS struct that has such a
* pointer is get/put, the refcount update is also propagated to
* the referenced struct, this ensure that it cannot get removed
* while somebody is using the probe response version.
*
* Note that the hidden_beacon_bss pointer never changes, due to
* the reference counting. Therefore, no locking is needed for
* it.
*
* Also note that the hidden_beacon_bss pointer is only relevant
* if the driver uses something other than the IEs, e.g. private
* data stored stored in the BSS struct, since the beacon IEs are
* also linked into the probe response struct.
*/
#define IEEE80211_SCAN_RESULT_EXPIRE (30 * HZ)
static void bss_free(st
