net/wireless/scan.c - kernel/msm - Gitiles

 /*
  * 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 (bss->hold ||
 		    !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)
 		return false;
 	if (memcmp(ie + 2, meshid, meshidlen))
 		return false;

 	ie = find_ie(WLAN_EID_MESH_CONFIG,
 		     a->information_elements,
 		     a->len_information_elements);
 	if (ie[1] != IEEE80211_MESH_CONFIG_LEN)
 		return false;

 	/*
 	 * Ignore mesh capability (last two bytes of the IE) when
 	 * comparing since that may differ between stations taking
 	 * part in the same mesh.
 	 */
 	return memcmp(ie + 2, meshcfg, IEEE80211_MESH_CONFIG_LEN - 2) == 0;
 }

 static int cmp_bss(struct cfg80211_bss *a,
 		   struct cfg80211_bss *b)
 {
 	int r;

 	if (a->channel != b->channel)
 		return b->channel->center_freq - a->channel->center_freq;

 	r = memcmp(a->bssid, b->bssid, ETH_ALEN);
 	if (r)
 		return r;

 	if (is_zero_ether_addr(a->bssid)) {
 		r = cmp_ies(WLAN_EID_MESH_ID,
 			    a->information_elements,
 			    a->len_information_elements,
 			    b->information_elements,
 			    b->len_information_elements);
 		if (r)
 			return r;
 		return cmp_ies(WLAN_EID_MESH_CONFIG,
 			       a->information_elements,
 			       a->len_information_elements,
 			       b->information_elements,
 			       b->len_information_elements);
 	}

 	return cmp_ies(WLAN_EID_SSID,
 		       a->information_elements,
 		       a->len_information_elements,
 		       b->information_elements,
 		       b->len_information_elements);
 }

 struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
 				      struct ieee80211_channel *channel,
 				      const u8 *bssid,
 				      const u8 *ssid, size_t ssid_len,
 				      u16 capa_mask, u16 capa_val)
 {
 	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
 	struct cfg80211_internal_bss *bss, *res = NULL;

 	spin_lock_bh(&dev->bss_lock);

 	list_for_each_entry(bss, &dev->bss_list, list) {
 		if ((bss->pub.capability & capa_mask) != capa_val)
 			continue;
 		if (channel && bss->pub.channel != channel)
 			continue;
 		if (is_bss(&bss->pub, bssid, ssid, ssid_len)) {
 			res = bss;
 			kref_get(&res->ref);
 			break;
 		}
 	}

 	spin_unlock_bh(&dev->bss_lock);
 	if (!res)
 		return NULL;
 	return &res->pub;
 }
 EXPORT_SYMBOL(cfg80211_get_bss);

 struct cfg80211_bss *cfg80211_get_mesh(struct wiphy *wiphy,
 				       struct ieee80211_channel *channel,
 				       const u8 *meshid, size_t meshidlen,
 				       const u8 *meshcfg)
 {
 	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
 	struct cfg80211_internal_bss *bss, *res = NULL;

 	spin_lock_bh(&dev->bss_lock);

 	list_for_each_entry(bss, &dev->bss_list, list) {
 		if (channel && bss->pub.channel != channel)
 			continue;
 		if (is_mesh(&bss->pub, meshid, meshidlen, meshcfg)) {
 			res = bss;
 			kref_get(&res->ref);
 			break;
 		}
 	}

 	spin_unlock_bh(&dev->bss_lock);
 	if (!res)
 		return NULL;
 	return &res->pub;
 }
 EXPORT_SYMBOL(cfg80211_get_mesh);


 static void rb_insert_bss(struct cfg80211_registered_device *dev,
 			  struct cfg80211_internal_bss *bss)
 {
 	struct rb_node **p = &dev->bss_tree.rb_node;
 	struct rb_node *parent = NULL;
 	struct cfg80211_internal_bss *tbss;
 	int cmp;

 	while (*p) {
 		parent = *p;
 		tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);

 		cmp = cmp_bss(&bss->pub, &tbss->pub);

 		if (WARN_ON(!cmp)) {
 			/* will sort of leak this BSS */
 			return;
 		}

 		if (cmp < 0)
 			p = &(*p)->rb_left;
 		else
 			p = &(*p)->rb_right;
 	}

 	rb_link_node(&bss->rbn, parent, p);
 	rb_insert_color(&bss->rbn, &dev->bss_tree);
 }

 static struct cfg80211_internal_bss *
 rb_find_bss(struct cfg80211_registered_device *dev,
 	    struct cfg80211_internal_bss *res)
 {
 	struct rb_node *n = dev->bss_tree.rb_node;
 	struct cfg80211_internal_bss *bss;
 	int r;

 	while (n) {
 		bss = rb_entry(n, struct cfg80211_internal_bss, rbn);
 		r = cmp_bss(&res->pub, &bss->pub);

 		if (r == 0)
 			return bss;
 		else if (r < 0)
 			n = n->rb_left;
 		else
 			n = n->rb_right;
 	}

 	return NULL;
 }

 static struct cfg80211_internal_bss *
 cfg80211_bss_update(struct cfg80211_registered_device *dev,
 		    struct cfg80211_internal_bss *res,
 		    bool overwrite)
 {
 	struct cfg80211_internal_bss *found = NULL;
 	const u8 *meshid, *meshcfg;

 	/*
 	 * The reference to "res" is donated to this function.
 	 */

 	if (WARN_ON(!res->pub.channel)) {
 		kref_put(&res->ref, bss_release);
 		return NULL;
 	}

 	res->ts = jiffies;

 	if (is_zero_ether_addr(res->pub.bssid)) {
 		/* must be mesh, verify */
 		meshid = find_ie(WLAN_EID_MESH_ID, res->pub.information_elements,
 				 res->pub.len_information_elements);
 		meshcfg = find_ie(WLAN_EID_MESH_CONFIG,
 				  res->pub.information_elements,
 				  res->pub.len_information_elements);
 		if (!meshid || !meshcfg ||
 		    meshcfg[1] != IEEE80211_MESH_CONFIG_LEN) {
 			/* bogus mesh */
 			kref_put(&res->ref, bss_release);
 			return NULL;
 		}
 	}

 	spin_lock_bh(&dev->bss_lock);

 	found = rb_find_bss(dev, res);

 	if (found && overwrite) {
 		list_replace(&found->list, &res->list);
 		rb_replace_node(&found->rbn, &res->rbn,
 				&dev->bss_tree);
 		kref_put(&found->ref, bss_release);
 		found = res;
 	} else if (found) {
 		kref_get(&found->ref);
 		found->pub.beacon_interval = res->pub.beacon_interval;
 		found->pub.tsf = res->pub.tsf;
 		found->pub.signal = res->pub.signal;
 		found->pub.capability = res->pub.capability;
 		found->ts = res->ts;
 		kref_put(&res->ref, bss_release);
 	} else {
 		/* this "consumes" the reference */
 		list_add_tail(&res->list, &dev->bss_list);
 		rb_insert_bss(dev, res);
 		found = res;
 	}

 	dev->bss_generation++;
 	spin_unlock_bh(&dev->bss_lock);

 	kref_get(&found->ref);
 	return found;
 }

 struct cfg80211_bss *
 cfg80211_inform_bss_frame(struct wiphy *wiphy,
 			  struct ieee80211_channel *channel,
 			  struct ieee80211_mgmt *mgmt, size_t len,
 			  s32 signal, gfp_t gfp)
 {
 	struct cfg80211_internal_bss *res;
 	size_t ielen = len - offsetof(struct ieee80211_mgmt,
 				      u.probe_resp.variable);
 	bool overwrite;
 	size_t privsz = wiphy->bss_priv_size;

 	if (WARN_ON(wiphy->signal_type == NL80211_BSS_SIGNAL_UNSPEC &&
 	            (signal < 0 || signal > 100)))
 		return NULL;

 	if (WARN_ON(!mgmt || !wiphy ||
 		    len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
 		return NULL;

 	res = kzalloc(sizeof(*res) + privsz + ielen, gfp);
 	if (!res)
 		return NULL;

 	memcpy(res->pub.bssid, mgmt->bssid, ETH_ALEN);
 	res->pub.channel = channel;
 	res->pub.signal = signal;
 	res->pub.tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
 	res->pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
 	res->pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
 	/* point to after the private area */
 	res->pub.information_elements = (u8 *)res + sizeof(*res) + privsz;
 	memcpy(res->pub.information_elements, mgmt->u.probe_resp.variable, ielen);
 	res->pub.len_information_elements = ielen;

 	kref_init(&res->ref);

 	overwrite = ieee80211_is_probe_resp(mgmt->frame_control);

 	res = cfg80211_bss_update(wiphy_to_dev(wiphy), res, overwrite);
 	if (!res)
 		return NULL;

 	if (res->pub.capability & WLAN_CAPABILITY_ESS)
 		regulatory_hint_found_beacon(wiphy, channel, gfp);

 	/* cfg80211_bss_update gives us a referenced result */
 	return &res->pub;
 }
 EXPORT_SYMBOL(cfg80211_inform_bss_frame);

 void cfg80211_put_bss(struct cfg80211_bss *pub)
 {
 	struct cfg80211_internal_bss *bss;

 	if (!pub)
 		return;

 	bss = container_of(pub, struct cfg80211_internal_bss, pub);
 	kref_put(&bss->ref, bss_release);
 }
 EXPORT_SYMBOL(cfg80211_put_bss);

 void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
 {
 	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
 	struct cfg80211_internal_bss *bss;

 	if (WARN_ON(!pub))
 		return;

 	bss = container_of(pub, struct cfg80211_internal_bss, pub);

 	spin_lock_bh(&dev->bss_lock);

 	list_del(&bss->list);
 	rb_erase(&bss->rbn, &dev->bss_tree);

 	spin_unlock_bh(&dev->bss_lock);

 	kref_put(&bss->ref, bss_release);
 }
 EXPORT_SYMBOL(cfg80211_unlink_bss);

 void cfg80211_hold_bss(struct cfg80211_bss *pub)
 {
 	struct cfg80211_internal_bss *bss;

 	if (!pub)
 		return;

 	bss = container_of(pub, struct cfg80211_internal_bss, pub);
 	bss->hold = true;
 }
 EXPORT_SYMBOL(cfg80211_hold_bss);

 void cfg80211_unhold_bss(struct cfg80211_bss *pub)
 {
 	struct cfg80211_internal_bss *bss;

 	if (!pub)
 		return;

 	bss = container_of(pub, struct cfg80211_internal_bss, pub);
 	bss->hold = false;
 }
 EXPORT_SYMBOL(cfg80211_unhold_bss);

 #ifdef CONFIG_WIRELESS_EXT
 int cfg80211_wext_siwscan(struct net_device *dev,
 			  struct iw_request_info *info,
 			  union iwreq_data *wrqu, char *extra)
 {
 	struct cfg80211_registered_device *rdev;
 	struct wiphy *wiphy;
 	struct iw_scan_req *wreq = NULL;
 	struct cfg80211_scan_request *creq;
 	int i, err, n_channels = 0;
 	enum ieee80211_band band;

 	if (!netif_running(dev))
 		return -ENETDOWN;

 	rdev = cfg80211_get_dev_from_ifindex(dev->ifindex);

 	if (IS_ERR(rdev))
 		return PTR_ERR(rdev);

 	if (rdev->scan_req) {
 		err = -EBUSY;
 		goto out;
 	}

 	wiphy = &rdev->wiphy;

 	for (band = 0; band < IEEE80211_NUM_BANDS; band++)
 		if (wiphy->bands[band])
 			n_channels += wiphy->bands[band]->n_channels;

 	creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
 		       n_channels * sizeof(void *),
 		       GFP_ATOMIC);
 	if (!creq) {
 		err = -ENOMEM;
 		goto out;
 	}

 	creq->wiphy = wiphy;
 	creq->ifidx = dev->ifindex;
 	creq->ssids = (void *)(creq + 1);
 	creq->channels = (void *)(creq->ssids + 1);
 	creq->n_channels = n_channels;
 	creq->n_ssids = 1;

 	/* all channels */
 	i = 0;
 	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 		int j;
 		if (!wiphy->bands[band])
 			continue;
 		for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
 			creq->channels[i] = &wiphy->bands[band]->channels[j];
 			i++;
 		}
 	}

 	/* translate scan request */
 	if (wrqu->data.length == sizeof(struct iw_scan_req)) {
 		wreq = (struct iw_scan_req *)extra;

 		if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
 			if (wreq->essid_len > IEEE80211_MAX_SSID_LEN)
 				return -EINVAL;
 			memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
 			creq->ssids[0].ssid_len = wreq->essid_len;
 		}
 		if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE)
 			creq->n_ssids = 0;
 	}

 	rdev->scan_req = creq;
 	err = rdev->ops->scan(wiphy, dev, creq);
 	if (err) {
 		rdev->scan_req = NULL;
 		kfree(creq);
 	}
  out:
 	cfg80211_put_dev(rdev);
 	return err;
 }
 EXPORT_SYMBOL(cfg80211_wext_siwscan);

 static void ieee80211_scan_add_ies(struct iw_request_info *info,
 				   struct cfg80211_bss *bss,
 				   char **current_ev, char *end_buf)
 {
 	u8 *pos, *end, *next;
 	struct iw_event iwe;

 	if (!bss->information_elements ||
 	    !bss->len_information_elements)
 		return;

 	/*
 	 * If needed, fragment the IEs buffer (at IE boundaries) into short
 	 * enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
 	 */
 	pos = bss->information_elements;
 	end = pos + bss->len_information_elements;

 	while (end - pos > IW_GENERIC_IE_MAX) {
 		next = pos + 2 + pos[1];
 		while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
 			next = next + 2 + next[1];

 		memset(&iwe, 0, sizeof(iwe));
 		iwe.cmd = IWEVGENIE;
 		iwe.u.data.length = next - pos;
 		*current_ev = iwe_stream_add_point(info, *current_ev,
 						   end_buf, &iwe, pos);

 		pos = next;
 	}

 	if (end > pos) {
 		memset(&iwe, 0, sizeof(iwe));
 		iwe.cmd = IWEVGENIE;
 		iwe.u.data.length = end - pos;
 		*current_ev = iwe_stream_add_point(info, *current_ev,
 						   end_buf, &iwe, pos);
 	}
 }

 static inline unsigned int elapsed_jiffies_msecs(unsigned long start)
 {
 	unsigned long end = jiffies;

 	if (end >= start)
 		return jiffies_to_msecs(end - start);

 	return jiffies_to_msecs(end + (MAX_JIFFY_OFFSET - start) + 1);
 }

 static char *
 ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info,
 	      struct cfg80211_internal_bss *bss, char *current_ev,
 	      char *end_buf)
 {
 	struct iw_event iwe;
 	u8 *buf, *cfg, *p;
 	u8 *ie = bss->pub.information_elements;
 	int rem = bss->pub.len_information_elements, i, sig;
 	bool ismesh = false;

 	memset(&iwe, 0, sizeof(iwe));
 	iwe.cmd = SIOCGIWAP;
 	iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
 	memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN);
 	current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
 					  IW_EV_ADDR_LEN);

 	memset(&iwe, 0, sizeof(iwe));
 	iwe.cmd = SIOCGIWFREQ;
 	iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq);
 	iwe.u.freq.e = 0;
 	current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
 					  IW_EV_FREQ_LEN);

 	memset(&iwe, 0, sizeof(iwe));
 	iwe.cmd = SIOCGIWFREQ;
 	iwe.u.freq.m = bss->pub.channel->center_freq;
 	iwe.u.freq.e = 6;
 	current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
 					  IW_EV_FREQ_LEN);

 	if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) {
 		memset(&iwe, 0, sizeof(iwe));
 		iwe.cmd = IWEVQUAL;
 		iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED |
 				     IW_QUAL_NOISE_INVALID |
 				     IW_QUAL_QUAL_UPDATED;
 		switch (wiphy->signal_type) {
 		case CFG80211_SIGNAL_TYPE_MBM:
 			sig = bss->pub.signal / 100;
 			iwe.u.qual.level = sig;
 			iwe.u.qual.updated |= IW_QUAL_DBM;
 			if (sig < -110)		/* rather bad */
 				sig = -110;
 			else if (sig > -40)	/* perfect */
 				sig = -40;
 			/* will give a range of 0 .. 70 */
 			iwe.u.qual.qual = sig + 110;
 			break;
 		case CFG80211_SIGNAL_TYPE_UNSPEC:
 			iwe.u.qual.level = bss->pub.signal;
 			/* will give range 0 .. 100 */
 			iwe.u.qual.qual = bss->pub.signal;
 			break;
 		default:
 			/* not reached */
 			break;
 		}
 		current_ev = iwe_stream_add_event(info, current_ev, end_buf,
 						  &iwe, IW_EV_QUAL_LEN);
 	}

 	memset(&iwe, 0, sizeof(iwe));
 	iwe.cmd = SIOCGIWENCODE;
 	if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY)
 		iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
 	else
 		iwe.u.data.flags = IW_ENCODE_DISABLED;
 	iwe.u.data.length = 0;
 	current_ev = iwe_stream_add_point(info, current_ev, end_buf,
 					  &iwe, "");

 	while (rem >= 2) {
 		/* invalid data */
 		if (ie[1] > rem - 2)
 			break;

 		switch (ie[0]) {
 		case WLAN_EID_SSID:
 			memset(&iwe, 0, sizeof(iwe));
 			iwe.cmd = SIOCGIWESSID;
 			iwe.u.data.length = ie[1];
 			iwe.u.data.flags = 1;
 			current_ev = iwe_stream_add_point(info, current_ev, end_buf,
 							  &iwe, ie + 2);
 			break;
 		case WLAN_EID_MESH_ID:
 			memset(&iwe, 0, sizeof(iwe));
 			iwe.cmd = SIOCGIWESSID;
 			iwe.u.data.length = ie[1];
 			iwe.u.data.flags = 1;
 			current_ev = iwe_stream_add_point(info, current_ev, end_buf,
 							  &iwe, ie + 2);
 			break;
 		case WLAN_EID_MESH_CONFIG:
 			ismesh = true;
 			if (ie[1] != IEEE80211_MESH_CONFIG_LEN)
 				break;
 			buf = kmalloc(50, GFP_ATOMIC);
 			if (!buf)
 				break;
 			cfg = ie + 2;
 			memset(&iwe, 0, sizeof(iwe));
 			iwe.cmd = IWEVCUSTOM;
 			sprintf(buf, "Mesh network (version %d)", cfg[0]);
 			iwe.u.data.length = strlen(buf);
 			current_ev = iwe_stream_add_point(info, current_ev,
 							  end_buf,
 							  &iwe, buf);
 			sprintf(buf, "Path Selection Protocol ID: "
 				"0x%02X%02X%02X%02X", cfg[1], cfg[2], cfg[3],
 							cfg[4]);
 			iwe.u.data.length = strlen(buf);
 			current_ev = iwe_stream_add_point(info, current_ev,
 							  end_buf,
 							  &iwe, buf);
 			sprintf(buf, "Path Selection Metric ID: "
 				"0x%02X%02X%02X%02X", cfg[5], cfg[6], cfg[7],
 							cfg[8]);
 			iwe.u.data.length = strlen(buf);
 			current_ev = iwe_stream_add_point(info, current_ev,
 							  end_buf,
 							  &iwe, buf);
 			sprintf(buf, "Congestion Control Mode ID: "
 				"0x%02X%02X%02X%02X", cfg[9], cfg[10],
 							cfg[11], cfg[12]);
 			iwe.u.data.length = strlen(buf);
 			current_ev = iwe_stream_add_point(info, current_ev,
 							  end_buf,
 							  &iwe, buf);
 			sprintf(buf, "Channel Precedence: "
 				"0x%02X%02X%02X%02X", cfg[13], cfg[14],
 							cfg[15], cfg[16]);
 			iwe.u.data.length = strlen(buf);
 			current_ev = iwe_stream_add_point(info, current_ev,
 							  end_buf,
 							  &iwe, buf);
 			kfree(buf);
 			break;
 		case WLAN_EID_SUPP_RATES:
 		case WLAN_EID_EXT_SUPP_RATES:
 			/* display all supported rates in readable format */
 			p = current_ev + iwe_stream_lcp_len(info);

 			memset(&iwe, 0, sizeof(iwe));
 			iwe.cmd = SIOCGIWRATE;
 			/* Those two flags are ignored... */
 			iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;

 			for (i = 0; i < ie[1]; i++) {
 				iwe.u.bitrate.value =
 					((ie[i + 2] & 0x7f) * 500000);
 				p = iwe_stream_add_value(info, current_ev, p,
 						end_buf, &iwe, IW_EV_PARAM_LEN);
 			}
 			current_ev = p;
 			break;
 		}
 		rem -= ie[1] + 2;
 		ie += ie[1] + 2;
 	}

 	if (bss->pub.capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS)
 	    || ismesh) {
 		memset(&iwe, 0, sizeof(iwe));
 		iwe.cmd = SIOCGIWMODE;
 		if (ismesh)
 			iwe.u.mode = IW_MODE_MESH;
 		else if (bss->pub.capability & WLAN_CAPABILITY_ESS)
 			iwe.u.mode = IW_MODE_MASTER;
 		else
 			iwe.u.mode = IW_MODE_ADHOC;
 		current_ev = iwe_stream_add_event(info, current_ev, end_buf,
 						  &iwe, IW_EV_UINT_LEN);
 	}

 	buf = kmalloc(30, GFP_ATOMIC);
 	if (buf) {
 		memset(&iwe, 0, sizeof(iwe));
 		iwe.cmd = IWEVCUSTOM;
 		sprintf(buf, "tsf=%016llx", (unsigned long long)(bss->pub.tsf));
 		iwe.u.data.length = strlen(buf);
 		current_ev = iwe_stream_add_point(info, current_ev, end_buf,
 						  &iwe, buf);
 		memset(&iwe, 0, sizeof(iwe));
 		iwe.cmd = IWEVCUSTOM;
 		sprintf(buf, " Last beacon: %ums ago",
 			elapsed_jiffies_msecs(bss->ts));
 		iwe.u.data.length = strlen(buf);
 		current_ev = iwe_stream_add_point(info, current_ev,
 						  end_buf, &iwe, buf);
 		kfree(buf);
 	}

 	ieee80211_scan_add_ies(info, &bss->pub, &current_ev, end_buf);

 	return current_ev;
 }


 static int ieee80211_scan_results(struct cfg80211_registered_device *dev,
 				  struct iw_request_info *info,
 				  char *buf, size_t len)
 {
 	char *current_ev = buf;
 	char *end_buf = buf + len;
 	struct cfg80211_internal_bss *bss;

 	spin_lock_bh(&dev->bss_lock);
 	cfg80211_bss_expire(dev);

 	list_for_each_entry(bss, &dev->bss_list, list) {
 		if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
 			spin_unlock_bh(&dev->bss_lock);
 			return -E2BIG;
 		}
 		current_ev = ieee80211_bss(&dev->wiphy, info, bss,
 					   current_ev, end_buf);
 	}
 	spin_unlock_bh(&dev->bss_lock);
 	return current_ev - buf;
 }


 int cfg80211_wext_giwscan(struct net_device *dev,
 			  struct iw_request_info *info,
 			  struct iw_point *data, char *extra)
 {
 	struct cfg80211_registered_device *rdev;
 	int res;

 	if (!netif_running(dev))
 		return -ENETDOWN;

 	rdev = cfg80211_get_dev_from_ifindex(dev->ifindex);

 	if (IS_ERR(rdev))
 		return PTR_ERR(rdev);

 	if (rdev->scan_req) {
 		res = -EAGAIN;
 		goto out;
 	}

 	res = ieee80211_scan_results(rdev, info, extra, data->length);
 	data->length = 0;
 	if (res >= 0) {
 		data->length = res;
 		res = 0;
 	}

  out:
 	cfg80211_put_dev(rdev);
 	return res;
 }
 EXPORT_SYMBOL(cfg80211_wext_giwscan);
 #endif
	/*
	* 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 (bss->hold \|\|
	!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)
	return false;
	if (memcmp(ie + 2, meshid, meshidlen))
	return false;

	ie = find_ie(WLAN_EID_MESH_CONFIG,
	a->information_elements,
	a->len_information_elements);
	if (ie[1] != IEEE80211_MESH_CONFIG_LEN)
	return false;

	/*
	* Ignore mesh capability (last two bytes of the IE) when
	* comparing since that may differ between stations taking
	* part in the same mesh.
	*/
	return memcmp(ie + 2, meshcfg, IEEE80211_MESH_CONFIG_LEN - 2) == 0;
	}

	static int cmp_bss(struct cfg80211_bss *a,
	struct cfg80211_bss *b)
	{
	int r;

	if (a->channel != b->channel)
	return b->channel->center_freq - a->channel->center_freq;

	r = memcmp(a->bssid, b->bssid, ETH_ALEN);
	if (r)
	return r;

	if (is_zero_ether_addr(a->bssid)) {
	r = cmp_ies(WLAN_EID_MESH_ID,
	a->information_elements,
	a->len_information_elements,
	b->information_elements,
	b->len_information_elements);
	if (r)
	return r;
	return cmp_ies(WLAN_EID_MESH_CONFIG,
	a->information_elements,
	a->len_information_elements,
	b->information_elements,
	b->len_information_elements);
	}

	return cmp_ies(WLAN_EID_SSID,
	a->information_elements,
	a->len_information_elements,
	b->information_elements,
	b->len_information_elements);
	}

	struct cfg80211_bss cfg80211_get_bss(struct wiphy wiphy,
	struct ieee80211_channel *channel,
	const u8 *bssid,
	const u8 *ssid, size_t ssid_len,
	u16 capa_mask, u16 capa_val)
	{
	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
	struct cfg80211_internal_bss bss, res = NULL;

	spin_lock_bh(&dev->bss_lock);

	list_for_each_entry(bss, &dev->bss_list, list) {
	if ((bss->pub.capability & capa_mask) != capa_val)
	continue;
	if (channel && bss->pub.channel != channel)
	continue;
	if (is_bss(&bss->pub, bssid, ssid, ssid_len)) {
	res = bss;
	kref_get(&res->ref);
	break;
	}
	}

	spin_unlock_bh(&dev->bss_lock);
	if (!res)
	return NULL;
	return &res->pub;
	}
	EXPORT_SYMBOL(cfg80211_get_bss);

	struct cfg80211_bss cfg80211_get_mesh(struct wiphy wiphy,
	struct ieee80211_channel *channel,
	const u8 *meshid, size_t meshidlen,
	const u8 *meshcfg)
	{
	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
	struct cfg80211_internal_bss bss, res = NULL;

	spin_lock_bh(&dev->bss_lock);

	list_for_each_entry(bss, &dev->bss_list, list) {
	if (channel && bss->pub.channel != channel)
	continue;
	if (is_mesh(&bss->pub, meshid, meshidlen, meshcfg)) {
	res = bss;
	kref_get(&res->ref);
	break;
	}
	}

	spin_unlock_bh(&dev->bss_lock);
	if (!res)
	return NULL;
	return &res->pub;
	}
	EXPORT_SYMBOL(cfg80211_get_mesh);


	static void rb_insert_bss(struct cfg80211_registered_device *dev,
	struct cfg80211_internal_bss *bss)
	{
	struct rb_node **p = &dev->bss_tree.rb_node;
	struct rb_node *parent = NULL;
	struct cfg80211_internal_bss *tbss;
	int cmp;

	while (*p) {
	parent = *p;
	tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);

	cmp = cmp_bss(&bss->pub, &tbss->pub);

	if (WARN_ON(!cmp)) {
	/* will sort of leak this BSS */
	return;
	}

	if (cmp < 0)
	p = &(*p)->rb_left;
	else
	p = &(*p)->rb_right;
	}

	rb_link_node(&bss->rbn, parent, p);
	rb_insert_color(&bss->rbn, &dev->bss_tree);
	}

	static struct cfg80211_internal_bss *
	rb_find_bss(struct cfg80211_registered_device *dev,
	struct cfg80211_internal_bss *res)
	{
	struct rb_node *n = dev->bss_tree.rb_node;
	struct cfg80211_internal_bss *bss;
	int r;

	while (n) {
	bss = rb_entry(n, struct cfg80211_internal_bss, rbn);
	r = cmp_bss(&res->pub, &bss->pub);

	if (r == 0)
	return bss;
	else if (r < 0)
	n = n->rb_left;
	else
	n = n->rb_right;
	}

	return NULL;
	}

	static struct cfg80211_internal_bss *
	cfg80211_bss_update(struct cfg80211_registered_device *dev,
	struct cfg80211_internal_bss *res,
	bool overwrite)
	{
	struct cfg80211_internal_bss *found = NULL;
	const u8 meshid, meshcfg;

	/*
	* The reference to "res" is donated to this function.
	*/

	if (WARN_ON(!res->pub.channel)) {
	kref_put(&res->ref, bss_release);
	return NULL;
	}

	res->ts = jiffies;

	if (is_zero_ether_addr(res->pub.bssid)) {
	/* must be mesh, verify */
	meshid = find_ie(WLAN_EID_MESH_ID, res->pub.information_elements,
	res->pub.len_information_elements);
	meshcfg = find_ie(WLAN_EID_MESH_CONFIG,
	res->pub.information_elements,
	res->pub.len_information_elements);
	if (!meshid \|\| !meshcfg \|\|
	meshcfg[1] != IEEE80211_MESH_CONFIG_LEN) {
	/* bogus mesh */
	kref_put(&res->ref, bss_release);
	return NULL;
	}
	}

	spin_lock_bh(&dev->bss_lock);

	found = rb_find_bss(dev, res);

	if (found && overwrite) {
	list_replace(&found->list, &res->list);
	rb_replace_node(&found->rbn, &res->rbn,
	&dev->bss_tree);
	kref_put(&found->ref, bss_release);
	found = res;
	} else if (found) {
	kref_get(&found->ref);
	found->pub.beacon_interval = res->pub.beacon_interval;
	found->pub.tsf = res->pub.tsf;
	found->pub.signal = res->pub.signal;
	found->pub.capability = res->pub.capability;
	found->ts = res->ts;
	kref_put(&res->ref, bss_release);
	} else {
	/* this "consumes" the reference */
	list_add_tail(&res->list, &dev->bss_list);
	rb_insert_bss(dev, res);
	found = res;
	}

	dev->bss_generation++;
	spin_unlock_bh(&dev->bss_lock);

	kref_get(&found->ref);
	return found;
	}

	struct cfg80211_bss *
	cfg80211_inform_bss_frame(struct wiphy *wiphy,
	struct ieee80211_channel *channel,
	struct ieee80211_mgmt *mgmt, size_t len,
	s32 signal, gfp_t gfp)
	{
	struct cfg80211_internal_bss *res;
	size_t ielen = len - offsetof(struct ieee80211_mgmt,
	u.probe_resp.variable);
	bool overwrite;
	size_t privsz = wiphy->bss_priv_size;

	if (WARN_ON(wiphy->signal_type == NL80211_BSS_SIGNAL_UNSPEC &&
	(signal < 0 \|\| signal > 100)))
	return NULL;

	if (WARN_ON(!mgmt \|\| !wiphy \|\|
	len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
	return NULL;

	res = kzalloc(sizeof(*res) + privsz + ielen, gfp);
	if (!res)
	return NULL;

	memcpy(res->pub.bssid, mgmt->bssid, ETH_ALEN);
	res->pub.channel = channel;
	res->pub.signal = signal;
	res->pub.tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
	res->pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
	res->pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
	/* point to after the private area */
	res->pub.information_elements = (u8 )res + sizeof(res) + privsz;
	memcpy(res->pub.information_elements, mgmt->u.probe_resp.variable, ielen);
	res->pub.len_information_elements = ielen;

	kref_init(&res->ref);

	overwrite = ieee80211_is_probe_resp(mgmt->frame_control);

	res = cfg80211_bss_update(wiphy_to_dev(wiphy), res, overwrite);
	if (!res)
	return NULL;

	if (res->pub.capability & WLAN_CAPABILITY_ESS)
	regulatory_hint_found_beacon(wiphy, channel, gfp);

	/* cfg80211_bss_update gives us a referenced result */
	return &res->pub;
	}
	EXPORT_SYMBOL(cfg80211_inform_bss_frame);

	void cfg80211_put_bss(struct cfg80211_bss *pub)
	{
	struct cfg80211_internal_bss *bss;

	if (!pub)
	return;

	bss = container_of(pub, struct cfg80211_internal_bss, pub);
	kref_put(&bss->ref, bss_release);
	}
	EXPORT_SYMBOL(cfg80211_put_bss);

	void cfg80211_unlink_bss(struct wiphy wiphy, struct cfg80211_bss pub)
	{
	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
	struct cfg80211_internal_bss *bss;

	if (WARN_ON(!pub))
	return;

	bss = container_of(pub, struct cfg80211_internal_bss, pub);

	spin_lock_bh(&dev->bss_lock);

	list_del(&bss->list);
	rb_erase(&bss->rbn, &dev->bss_tree);

	spin_unlock_bh(&dev->bss_lock);

	kref_put(&bss->ref, bss_release);
	}
	EXPORT_SYMBOL(cfg80211_unlink_bss);

	void cfg80211_hold_bss(struct cfg80211_bss *pub)
	{
	struct cfg80211_internal_bss *bss;

	if (!pub)
	return;

	bss = container_of(pub, struct cfg80211_internal_bss, pub);
	bss->hold = true;
	}
	EXPORT_SYMBOL(cfg80211_hold_bss);

	void cfg80211_unhold_bss(struct cfg80211_bss *pub)
	{
	struct cfg80211_internal_bss *bss;

	if (!pub)
	return;

	bss = container_of(pub, struct cfg80211_internal_bss, pub);
	bss->hold = false;
	}
	EXPORT_SYMBOL(cfg80211_unhold_bss);

	#ifdef CONFIG_WIRELESS_EXT
	int cfg80211_wext_siwscan(struct net_device *dev,
	struct iw_request_info *info,
	union iwreq_data wrqu, char extra)
	{
	struct cfg80211_registered_device *rdev;
	struct wiphy *wiphy;
	struct iw_scan_req *wreq = NULL;
	struct cfg80211_scan_request *creq;
	int i, err, n_channels = 0;
	enum ieee80211_band band;

	if (!netif_running(dev))
	return -ENETDOWN;

	rdev = cfg80211_get_dev_from_ifindex(dev->ifindex);

	if (IS_ERR(rdev))
	return PTR_ERR(rdev);

	if (rdev->scan_req) {
	err = -EBUSY;
	goto out;
	}

	wiphy = &rdev->wiphy;

	for (band = 0; band < IEEE80211_NUM_BANDS; band++)
	if (wiphy->bands[band])
	n_channels += wiphy->bands[band]->n_channels;

	creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
	n_channels * sizeof(void *),
	GFP_ATOMIC);
	if (!creq) {
	err = -ENOMEM;
	goto out;
	}

	creq->wiphy = wiphy;
	creq->ifidx = dev->ifindex;
	creq->ssids = (void *)(creq + 1);
	creq->channels = (void *)(creq->ssids + 1);
	creq->n_channels = n_channels;
	creq->n_ssids = 1;

	/* all channels */
	i = 0;
	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
	int j;
	if (!wiphy->bands[band])
	continue;
	for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
	creq->channels[i] = &wiphy->bands[band]->channels[j];
	i++;
	}
	}

	/* translate scan request */
	if (wrqu->data.length == sizeof(struct iw_scan_req)) {
	wreq = (struct iw_scan_req *)extra;

	if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
	if (wreq->essid_len > IEEE80211_MAX_SSID_LEN)
	return -EINVAL;
	memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
	creq->ssids[0].ssid_len = wreq->essid_len;
	}
	if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE)
	creq->n_ssids = 0;
	}

	rdev->scan_req = creq;
	err = rdev->ops->scan(wiphy, dev, creq);
	if (err) {
	rdev->scan_req = NULL;
	kfree(creq);
	}
	out:
	cfg80211_put_dev(rdev);
	return err;
	}
	EXPORT_SYMBOL(cfg80211_wext_siwscan);

	static void ieee80211_scan_add_ies(struct iw_request_info *info,
	struct cfg80211_bss *bss,
	char *current_ev, char end_buf)
	{
	u8 pos, end, *next;
	struct iw_event iwe;

	if (!bss->information_elements \|\|
	!bss->len_information_elements)
	return;

	/*
	* If needed, fragment the IEs buffer (at IE boundaries) into short
	* enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
	*/
	pos = bss->information_elements;
	end = pos + bss->len_information_elements;

	while (end - pos > IW_GENERIC_IE_MAX) {
	next = pos + 2 + pos[1];
	while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
	next = next + 2 + next[1];

	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = IWEVGENIE;
	iwe.u.data.length = next - pos;
	current_ev = iwe_stream_add_point(info, current_ev,
	end_buf, &iwe, pos);

	pos = next;
	}

	if (end > pos) {
	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = IWEVGENIE;
	iwe.u.data.length = end - pos;
	current_ev = iwe_stream_add_point(info, current_ev,
	end_buf, &iwe, pos);
	}
	}

	static inline unsigned int elapsed_jiffies_msecs(unsigned long start)
	{
	unsigned long end = jiffies;

	if (end >= start)
	return jiffies_to_msecs(end - start);

	return jiffies_to_msecs(end + (MAX_JIFFY_OFFSET - start) + 1);
	}

	static char *
	ieee80211_bss(struct wiphy wiphy, struct iw_request_info info,
	struct cfg80211_internal_bss bss, char current_ev,
	char *end_buf)
	{
	struct iw_event iwe;
	u8 buf, cfg, *p;
	u8 *ie = bss->pub.information_elements;
	int rem = bss->pub.len_information_elements, i, sig;
	bool ismesh = false;

	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = SIOCGIWAP;
	iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
	memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN);
	current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
	IW_EV_ADDR_LEN);

	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = SIOCGIWFREQ;
	iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq);
	iwe.u.freq.e = 0;
	current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
	IW_EV_FREQ_LEN);

	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = SIOCGIWFREQ;
	iwe.u.freq.m = bss->pub.channel->center_freq;
	iwe.u.freq.e = 6;
	current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
	IW_EV_FREQ_LEN);

	if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) {
	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = IWEVQUAL;
	iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED \|
	IW_QUAL_NOISE_INVALID \|
	IW_QUAL_QUAL_UPDATED;
	switch (wiphy->signal_type) {
	case CFG80211_SIGNAL_TYPE_MBM:
	sig = bss->pub.signal / 100;
	iwe.u.qual.level = sig;
	iwe.u.qual.updated \|= IW_QUAL_DBM;
	if (sig < -110) /* rather bad */
	sig = -110;
	else if (sig > -40) /* perfect */
	sig = -40;
	/* will give a range of 0 .. 70 */
	iwe.u.qual.qual = sig + 110;
	break;
	case CFG80211_SIGNAL_TYPE_UNSPEC:
	iwe.u.qual.level = bss->pub.signal;
	/* will give range 0 .. 100 */
	iwe.u.qual.qual = bss->pub.signal;
	break;
	default:
	/* not reached */
	break;
	}
	current_ev = iwe_stream_add_event(info, current_ev, end_buf,
	&iwe, IW_EV_QUAL_LEN);
	}

	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = SIOCGIWENCODE;
	if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY)
	iwe.u.data.flags = IW_ENCODE_ENABLED \| IW_ENCODE_NOKEY;
	else
	iwe.u.data.flags = IW_ENCODE_DISABLED;
	iwe.u.data.length = 0;
	current_ev = iwe_stream_add_point(info, current_ev, end_buf,
	&iwe, "");

	while (rem >= 2) {
	/* invalid data */
	if (ie[1] > rem - 2)
	break;

	switch (ie[0]) {
	case WLAN_EID_SSID:
	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = SIOCGIWESSID;
	iwe.u.data.length = ie[1];
	iwe.u.data.flags = 1;
	current_ev = iwe_stream_add_point(info, current_ev, end_buf,
	&iwe, ie + 2);
	break;
	case WLAN_EID_MESH_ID:
	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = SIOCGIWESSID;
	iwe.u.data.length = ie[1];
	iwe.u.data.flags = 1;
	current_ev = iwe_stream_add_point(info, current_ev, end_buf,
	&iwe, ie + 2);
	break;
	case WLAN_EID_MESH_CONFIG:
	ismesh = true;
	if (ie[1] != IEEE80211_MESH_CONFIG_LEN)
	break;
	buf = kmalloc(50, GFP_ATOMIC);
	if (!buf)
	break;
	cfg = ie + 2;
	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = IWEVCUSTOM;
	sprintf(buf, "Mesh network (version %d)", cfg[0]);
	iwe.u.data.length = strlen(buf);
	current_ev = iwe_stream_add_point(info, current_ev,
	end_buf,
	&iwe, buf);
	sprintf(buf, "Path Selection Protocol ID: "
	"0x%02X%02X%02X%02X", cfg[1], cfg[2], cfg[3],
	cfg[4]);
	iwe.u.data.length = strlen(buf);
	current_ev = iwe_stream_add_point(info, current_ev,
	end_buf,
	&iwe, buf);
	sprintf(buf, "Path Selection Metric ID: "
	"0x%02X%02X%02X%02X", cfg[5], cfg[6], cfg[7],
	cfg[8]);
	iwe.u.data.length = strlen(buf);
	current_ev = iwe_stream_add_point(info, current_ev,
	end_buf,
	&iwe, buf);
	sprintf(buf, "Congestion Control Mode ID: "
	"0x%02X%02X%02X%02X", cfg[9], cfg[10],
	cfg[11], cfg[12]);
	iwe.u.data.length = strlen(buf);
	current_ev = iwe_stream_add_point(info, current_ev,
	end_buf,
	&iwe, buf);
	sprintf(buf, "Channel Precedence: "
	"0x%02X%02X%02X%02X", cfg[13], cfg[14],
	cfg[15], cfg[16]);
	iwe.u.data.length = strlen(buf);
	current_ev = iwe_stream_add_point(info, current_ev,
	end_buf,
	&iwe, buf);
	kfree(buf);
	break;
	case WLAN_EID_SUPP_RATES:
	case WLAN_EID_EXT_SUPP_RATES:
	/* display all supported rates in readable format */
	p = current_ev + iwe_stream_lcp_len(info);

	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = SIOCGIWRATE;
	/* Those two flags are ignored... */
	iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;

	for (i = 0; i < ie[1]; i++) {
	iwe.u.bitrate.value =
	((ie[i + 2] & 0x7f) * 500000);
	p = iwe_stream_add_value(info, current_ev, p,
	end_buf, &iwe, IW_EV_PARAM_LEN);
	}
	current_ev = p;
	break;
	}
	rem -= ie[1] + 2;
	ie += ie[1] + 2;
	}

	if (bss->pub.capability & (WLAN_CAPABILITY_ESS \| WLAN_CAPABILITY_IBSS)
	\|\| ismesh) {
	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = SIOCGIWMODE;
	if (ismesh)
	iwe.u.mode = IW_MODE_MESH;
	else if (bss->pub.capability & WLAN_CAPABILITY_ESS)
	iwe.u.mode = IW_MODE_MASTER;
	else
	iwe.u.mode = IW_MODE_ADHOC;
	current_ev = iwe_stream_add_event(info, current_ev, end_buf,
	&iwe, IW_EV_UINT_LEN);
	}

	buf = kmalloc(30, GFP_ATOMIC);
	if (buf) {
	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = IWEVCUSTOM;
	sprintf(buf, "tsf=%016llx", (unsigned long long)(bss->pub.tsf));
	iwe.u.data.length = strlen(buf);
	current_ev = iwe_stream_add_point(info, current_ev, end_buf,
	&iwe, buf);
	memset(&iwe, 0, sizeof(iwe));
	iwe.cmd = IWEVCUSTOM;
	sprintf(buf, " Last beacon: %ums ago",
	elapsed_jiffies_msecs(bss->ts));
	iwe.u.data.length = strlen(buf);
	current_ev = iwe_stream_add_point(info, current_ev,
	end_buf, &iwe, buf);
	kfree(buf);
	}

	ieee80211_scan_add_ies(info, &bss->pub, &current_ev, end_buf);

	return current_ev;
	}


	static int ieee80211_scan_results(struct cfg80211_registered_device *dev,
	struct iw_request_info *info,
	char *buf, size_t len)
	{
	char *current_ev = buf;
	char *end_buf = buf + len;
	struct cfg80211_internal_bss *bss;

	spin_lock_bh(&dev->bss_lock);
	cfg80211_bss_expire(dev);

	list_for_each_entry(bss, &dev->bss_list, list) {
	if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
	spin_unlock_bh(&dev->bss_lock);
	return -E2BIG;
	}
	current_ev = ieee80211_bss(&dev->wiphy, info, bss,
	current_ev, end_buf);
	}
	spin_unlock_bh(&dev->bss_lock);
	return current_ev - buf;
	}


	int cfg80211_wext_giwscan(struct net_device *dev,
	struct iw_request_info *info,
	struct iw_point data, char extra)
	{
	struct cfg80211_registered_device *rdev;
	int res;

	if (!netif_running(dev))
	return -ENETDOWN;

	rdev = cfg80211_get_dev_from_ifindex(dev->ifindex);

	if (IS_ERR(rdev))
	return PTR_ERR(rdev);

	if (rdev->scan_req) {
	res = -EAGAIN;
	goto out;
	}

	res = ieee80211_scan_results(rdev, info, extra, data->length);
	data->length = 0;
	if (res >= 0) {
	data->length = res;
	res = 0;
	}

	out:
	cfg80211_put_dev(rdev);
	return res;
	}
	EXPORT_SYMBOL(cfg80211_wext_giwscan);
	#endif