path: root/net/wireless/scan.c

/*
 * cfg80211 scan result handling
 *
 * Copyright 2008 Johannes Berg <johannes@sipsolutions.net>
 */
#include <linux/kernel.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/iw_handler.h>
#include "core.h"
#include "nl80211.h"

#define IEEE80211_SCAN_RESULT_EXPIRE	(10 * HZ)

void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted)
{
	struct net_device *dev;
#ifdef CONFIG_WIRELESS_EXT
	union iwreq_data wrqu;
#endif

	dev = dev_get_by_index(&init_net, request->ifidx);
	if (!dev)
		goto out;

	WARN_ON(request != wiphy_to_dev(request->wiphy)->scan_req);
	wiphy_to_dev(request->wiphy)->scan_req = NULL;

	if (aborted)
		nl80211_send_scan_aborted(wiphy_to_dev(request->wiphy), dev);
	else
		nl80211_send_scan_done(wiphy_to_dev(request->wiphy), dev);

#ifdef CONFIG_WIRELESS_EXT
	if (!aborted) {
		memset(&wrqu, 0, sizeof(wrqu));

		wireless_send_event(dev, SIOCGIWSCAN, &wrqu, NULL);
	}
#endif

	dev_put(dev);

 out:
	kfree(request);
}
EXPORT_SYMBOL(cfg80211_scan_done);

static void bss_release(struct kref *ref)
{
	struct cfg80211_internal_bss *bss;

	bss = container_of(ref, struct cfg80211_internal_bss, ref);
	if (bss->pub.free_priv)
		bss->pub.free_priv(&bss->pub);
	kfree(bss);
}

/* must hold dev->bss_lock! */
void cfg80211_bss_age(struct cfg80211_registered_device *dev,
                      unsigned long age_secs)
{
	struct cfg80211_internal_bss *bss;
	unsigned long age_jiffies = msecs_to_jiffies(age_secs * MSEC_PER_SEC);

	list_for_each_entry(bss, &dev->bss_list, list) {
		bss->ts -= age_jiffies;
	}
}

/* must hold dev->bss_lock! */
void cfg80211_bss_expire(struct cfg80211_registered_device *dev)
{
	struct cfg80211_internal_bss *bss, *tmp;
	bool expired = false;

	list_for_each_entry_safe(bss, tmp, &dev->bss_list, list) {
		if (!time_after(jiffies, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE))
			continue;
		list_del(&bss->list);
		rb_erase(&bss->rbn, &dev->bss_tree);
		kref_put(&bss->ref, bss_release);
		expired = true;
	}

	if (expired)
		dev->bss_generation++;
}

static u8 *find_ie(u8 num, u8 *ies, size_t len)
{
	while (len > 2 && ies[0] != num) {
		len -= ies[1] + 2;
		ies += ies[1] + 2;
	}
	if (len < 2)
		return NULL;
	if (len < 2 + ies[1])
		return NULL;
	return ies;
}

static int cmp_ies(u8 num, u8 *ies1, size_t len1, u8 *ies2, size_t len2)
{
	const u8 *ie1 = find_ie(num, ies1, len1);
	const u8 *ie2 = find_ie(num, ies2, len2);
	int r;

	if (!ie1 && !ie2)
		return 0;
	if (!ie1)
		return -1;

	r = memcmp(ie1 + 2, ie2 + 2, min(ie1[1], ie2[1]));
	if (r == 0 && ie1[1] != ie2[1])
		return ie2[1] - ie1[1];
	return r;
}

static bool is_bss(struct cfg80211_bss *a,
		   const u8 *bssid,
		   const u8 *ssid, size_t ssid_len)
{
	const u8 *ssidie;

	if (bssid && compare_ether_addr(a->bssid, bssid))
		return false;

	if (!ssid)
		return true;

	ssidie = find_ie(WLAN_EID_SSID,
			 a->information_elements,
			 a->len_information_elements);
	if (!ssidie)
		return false;
	if (ssidie[1] != ssid_len)
		return false;
	return memcmp(ssidie + 2, ssid, ssid_len) == 0;
}

static bool is_mesh(struct cfg80211_bss *a,
		    const u8 *meshid, size_t meshidlen,
		    const u8 *meshcfg)
{
	const u8 *ie;

	if (!is_zero_ether_addr(a->bssid))
		return false;

	ie = find_ie(WLAN_EID_MESH_ID,
		     a->information_elements,
		     a->len_information_elements);
	if (!ie)
		return false;
	if (ie[1] != meshidlen)
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