cfg80211/nl80211: scanning (and mac80211 update to use it)

This patch adds basic scan capability to cfg80211/nl80211 and
changes mac80211 to use it. The BSS list that cfg80211 maintains
is made driver-accessible with a private area in each BSS struct,
but mac80211 doesn't yet use it. That's another large project.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

6 files changed, 1167 insertions, 1 deletions

diff --git a/net/wireless/Makefile b/net/wireless/Makefile
index 938a334c8dbc..dad43c24f695 100644
--- a/net/wireless/Makefile
+++ b/net/wireless/Makefile
@@ -5,7 +5,7 @@ obj-$(CONFIG_LIB80211_CRYPT_WEP) += lib80211_crypt_wep.o
 obj-$(CONFIG_LIB80211_CRYPT_CCMP) += lib80211_crypt_ccmp.o
 obj-$(CONFIG_LIB80211_CRYPT_TKIP) += lib80211_crypt_tkip.o
 
-cfg80211-y += core.o sysfs.o radiotap.o util.o reg.o
+cfg80211-y += core.o sysfs.o radiotap.o util.o reg.o scan.o
 cfg80211-$(CONFIG_WIRELESS_EXT) += wext-compat.o
 cfg80211-$(CONFIG_NL80211) += nl80211.o
 
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 125226476089..3cccd1390cea 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -240,6 +240,8 @@ struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
 	mutex_init(&drv->mtx);
 	mutex_init(&drv->devlist_mtx);
 	INIT_LIST_HEAD(&drv->netdev_list);
+	spin_lock_init(&drv->bss_lock);
+	INIT_LIST_HEAD(&drv->bss_list);
 
 	device_initialize(&drv->wiphy.dev);
 	drv->wiphy.dev.class = &ieee80211_class;
@@ -259,6 +261,9 @@ int wiphy_register(struct wiphy *wiphy)
 	int i;
 	u16 ifmodes = wiphy->interface_modes;
 
+	if (WARN_ON(wiphy->max_scan_ssids < 1))
+		return -EINVAL;
+
 	/* sanity check ifmodes */
 	WARN_ON(!ifmodes);
 	ifmodes &= ((1 << __NL80211_IFTYPE_AFTER_LAST) - 1) & ~1;
@@ -367,8 +372,11 @@ EXPORT_SYMBOL(wiphy_unregister);
 
 void cfg80211_dev_free(struct cfg80211_registered_device *drv)
 {
+	struct cfg80211_internal_bss *scan, *tmp;
 	mutex_destroy(&drv->mtx);
 	mutex_destroy(&drv->devlist_mtx);
+	list_for_each_entry_safe(scan, tmp, &drv->bss_list, list)
+		kfree(scan);
 	kfree(drv);
 }
 
diff --git a/net/wireless/core.h b/net/wireless/core.h
index f7fb9f413028..e29ad4cd464f 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -8,6 +8,8 @@
 #include <linux/mutex.h>
 #include <linux/list.h>
 #include <linux/netdevice.h>
+#include <linux/kref.h>
+#include <linux/rbtree.h>
 #include <net/genetlink.h>
 #include <net/wireless.h>
 #include <net/cfg80211.h>
@@ -41,6 +43,13 @@ struct cfg80211_registered_device {
 	struct mutex devlist_mtx;
 	struct list_head netdev_list;
 
+	/* BSSes/scanning */
+	spinlock_t bss_lock;
+	struct list_head bss_list;
+	struct rb_root bss_tree;
+	u32 bss_generation;
+	struct cfg80211_scan_request *scan_req; /* protected by RTNL */
+
 	/* must be last because of the way we do wiphy_priv(),
 	 * and it should at least be aligned to NETDEV_ALIGN */
 	struct wiphy wiphy __attribute__((__aligned__(NETDEV_ALIGN)));
@@ -56,6 +65,15 @@ struct cfg80211_registered_device *wiphy_to_dev(struct wiphy *wiphy)
 extern struct mutex cfg80211_drv_mutex;
 extern struct list_head cfg80211_drv_list;
 
+struct cfg80211_internal_bss {
+	struct list_head list;
+	struct rb_node rbn;
+	unsigned long ts;
+	struct kref ref;
+	/* must be last because of priv member */
+	struct cfg80211_bss pub;
+};
+
 /*
  * This function returns a pointer to the driver
  * that the genl_info item that is passed refers to.
@@ -94,4 +112,6 @@ extern int cfg80211_dev_rename(struct cfg80211_registered_device *drv,
 void ieee80211_set_bitrate_flags(struct wiphy *wiphy);
 void wiphy_update_regulatory(struct wiphy *wiphy, enum reg_set_by setby);
 
+void cfg80211_bss_expire(struct cfg80211_registered_device *dev);
+
 #endif /* __NET_WIRELESS_CORE_H */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d452396006ee..298a4de59948 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -14,6 +14,7 @@
 #include <linux/nl80211.h>
 #include <linux/rtnetlink.h>
 #include <linux/netlink.h>
+#include <linux/etherdevice.h>
 #include <net/genetlink.h>
 #include <net/cfg80211.h>
 #include "core.h"
@@ -109,6 +110,8 @@ static struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] __read_mostly = {
 	[NL80211_ATTR_MGMT_SUBTYPE] = { .type = NLA_U8 },
 	[NL80211_ATTR_IE] = { .type = NLA_BINARY,
 			      .len = IEEE80211_MAX_DATA_LEN },
+	[NL80211_ATTR_SCAN_FREQUENCIES] = { .type = NLA_NESTED },
+	[NL80211_ATTR_SCAN_SSIDS] = { .type = NLA_NESTED },
 };
 
 /* message building helper */
@@ -141,6 +144,8 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 
 	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, dev->idx);
 	NLA_PUT_STRING(msg, NL80211_ATTR_WIPHY_NAME, wiphy_name(&dev->wiphy));
+	NLA_PUT_U8(msg, NL80211_ATTR_MAX_NUM_SCAN_SSIDS,
+		   dev->wiphy.max_scan_ssids);
 
 	nl_modes = nla_nest_start(msg, NL80211_ATTR_SUPPORTED_IFTYPES);
 	if (!nl_modes)
@@ -2270,6 +2275,246 @@ static int nl80211_set_mgmt_extra_ie(struct sk_buff *skb,
 	return err;
 }
 
+static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *drv;
+	struct net_device *dev;
+	struct cfg80211_scan_request *request;
+	struct cfg80211_ssid *ssid;
+	struct ieee80211_channel *channel;
+	struct nlattr *attr;
+	struct wiphy *wiphy;
+	int err, tmp, n_ssids = 0, n_channels = 0, i;
+	enum ieee80211_band band;
+
+	err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev);
+	if (err)
+		return err;
+
+	wiphy = &drv->wiphy;
+
+	if (!drv->ops->scan) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	rtnl_lock();
+
+	if (drv->scan_req) {
+		err = -EBUSY;
+		goto out_unlock;
+	}
+
+	if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
+		nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_FREQUENCIES], tmp)
+			n_channels++;
+		if (!n_channels) {
+			err = -EINVAL;
+			goto out_unlock;
+		}
+	} else {
+		for (band = 0; band < IEEE80211_NUM_BANDS; band++)
+			if (wiphy->bands[band])
+				n_channels += wiphy->bands[band]->n_channels;
+	}
+
+	if (info->attrs[NL80211_ATTR_SCAN_SSIDS])
+		nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS], tmp)
+			n_ssids++;
+
+	if (n_ssids > wiphy->max_scan_ssids) {
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
+	request = kzalloc(sizeof(*request)
+			+ sizeof(*ssid) * n_ssids
+			+ sizeof(channel) * n_channels, GFP_KERNEL);
+	if (!request) {
+		err = -ENOMEM;
+		goto out_unlock;
+	}
+
+	request->channels = (void *)((char *)request + sizeof(*request));
+	request->n_channels = n_channels;
+	if (n_ssids)
+		request->ssids = (void *)(request->channels + n_channels);
+	request->n_ssids = n_ssids;
+
+	if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
+		/* user specified, bail out if channel not found */
+		request->n_channels = n_channels;
+		i = 0;
+		nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_FREQUENCIES], tmp) {
+			request->channels[i] = ieee80211_get_channel(wiphy, nla_get_u32(attr));
+			if (!request->channels[i]) {
+				err = -EINVAL;
+				goto out_free;
+			}
+			i++;
+		}
+	} else {
+		/* 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++) {
+				request->channels[i] = &wiphy->bands[band]->channels[j];
+				i++;
+			}
+		}
+	}
+
+	i = 0;
+	if (info->attrs[NL80211_ATTR_SCAN_SSIDS]) {
+		nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS], tmp) {
+			if (request->ssids[i].ssid_len > IEEE80211_MAX_SSID_LEN) {
+				err = -EINVAL;
+				goto out_free;
+			}
+			memcpy(request->ssids[i].ssid, nla_data(attr), nla_len(attr));
+			request->ssids[i].ssid_len = nla_len(attr);
+			i++;
+		}
+	}
+
+	request->ifidx = dev->ifindex;
+	request->wiphy = &drv->wiphy;
+
+	drv->scan_req = request;
+	err = drv->ops->scan(&drv->wiphy, dev, request);
+
+ out_free:
+	if (err) {
+		drv->scan_req = NULL;
+		kfree(request);
+	}
+ out_unlock:
+	rtnl_unlock();
+ out:
+	cfg80211_put_dev(drv);
+	dev_put(dev);
+	return err;
+}
+
+static int nl80211_send_bss(struct sk_buff *msg, u32 pid, u32 seq, int flags,
+			    struct cfg80211_registered_device *rdev,
+			    struct net_device *dev,
+			    struct cfg80211_bss *res)
+{
+	void *hdr;
+	struct nlattr *bss;
+
+	hdr = nl80211hdr_put(msg, pid, seq, flags,
+			     NL80211_CMD_NEW_SCAN_RESULTS);
+	if (!hdr)
+		return -1;
+
+	NLA_PUT_U32(msg, NL80211_ATTR_SCAN_GENERATION,
+		    rdev->bss_generation);
+	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, dev->ifindex);
+
+	bss = nla_nest_start(msg, NL80211_ATTR_BSS);
+	if (!bss)
+		goto nla_put_failure;
+	if (!is_zero_ether_addr(res->bssid))
+		NLA_PUT(msg, NL80211_BSS_BSSID, ETH_ALEN, res->bssid);
+	if (res->information_elements && res->len_information_elements)
+		NLA_PUT(msg, NL80211_BSS_INFORMATION_ELEMENTS,
+			res->len_information_elements,
+			res->information_elements);
+	if (res->tsf)
+		NLA_PUT_U64(msg, NL80211_BSS_TSF, res->tsf);
+	if (res->beacon_interval)
+		NLA_PUT_U16(msg, NL80211_BSS_BEACON_INTERVAL, res->beacon_interval);
+	NLA_PUT_U16(msg, NL80211_BSS_CAPABILITY, res->capability);
+	NLA_PUT_U32(msg, NL80211_BSS_FREQUENCY, res->channel->center_freq);
+
+	switch (res->signal_type) {
+	case CFG80211_SIGNAL_TYPE_MBM:
+		NLA_PUT_U32(msg, NL80211_BSS_SIGNAL_MBM, res->signal);
+		break;
+	case CFG80211_SIGNAL_TYPE_UNSPEC:
+		NLA_PUT_U8(msg, NL80211_BSS_SIGNAL_UNSPEC, res->signal);
+		break;
+	default:
+		break;
+	}
+
+	nla_nest_end(msg, bss);
+
+	return genlmsg_end(msg, hdr);
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+static int nl80211_dump_scan(struct sk_buff *skb,
+			     struct netlink_callback *cb)
+{
+	struct cfg80211_registered_device *dev;
+	struct net_device *netdev;
+	struct cfg80211_internal_bss *scan;
+	int ifidx = cb->args[0];
+	int start = cb->args[1], idx = 0;
+	int err;
+
+	if (!ifidx) {
+		err = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl80211_fam.hdrsize,
+				  nl80211_fam.attrbuf, nl80211_fam.maxattr,
+				  nl80211_policy);
+		if (err)
+			return err;
+
+		if (!nl80211_fam.attrbuf[NL80211_ATTR_IFINDEX])
+			return -EINVAL;
+
+		ifidx = nla_get_u32(nl80211_fam.attrbuf[NL80211_ATTR_IFINDEX]);
+		if (!ifidx)
+			return -EINVAL;
+		cb->args[0] = ifidx;
+	}
+
+	netdev = dev_get_by_index(&init_net, ifidx);
+	if (!netdev)
+		return -ENODEV;
+
+	dev = cfg80211_get_dev_from_ifindex(ifidx);
+	if (IS_ERR(dev)) {
+		err = PTR_ERR(dev);
+		goto out_put_netdev;
+	}
+
+	spin_lock_bh(&dev->bss_lock);
+	cfg80211_bss_expire(dev);
+
+	list_for_each_entry(scan, &dev->bss_list, list) {
+		if (++idx <= start)
+			continue;
+		if (nl80211_send_bss(skb,
+				NETLINK_CB(cb->skb).pid,
+				cb->nlh->nlmsg_seq, NLM_F_MULTI,
+				dev, netdev, &scan->pub) < 0) {
+			idx--;
+			goto out;
+		}
+	}
+
+ out:
+	spin_unlock_bh(&dev->bss_lock);
+
+	cb->args[1] = idx;
+	err = skb->len;
+	cfg80211_put_dev(dev);
+ out_put_netdev:
+	dev_put(netdev);
+
+	return err;
+}
+
 static struct genl_ops nl80211_ops[] = {
 	{
 		.cmd = NL80211_CMD_GET_WIPHY,
@@ -2443,12 +2688,26 @@ static struct genl_ops nl80211_ops[] = {
 		.policy = nl80211_policy,
 		.flags = GENL_ADMIN_PERM,
 	},
+	{
+		.cmd = NL80211_CMD_TRIGGER_SCAN,
+		.doit = nl80211_trigger_scan,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+	},
+	{
+		.cmd = NL80211_CMD_GET_SCAN,
+		.policy = nl80211_policy,
+		.dumpit = nl80211_dump_scan,
+	},
 };
 
 /* multicast groups */
 static struct genl_multicast_group nl80211_config_mcgrp = {
 	.name = "config",
 };
+static struct genl_multicast_group nl80211_scan_mcgrp = {
+	.name = "scan",
+};
 
 /* notification functions */
 
@@ -2468,6 +2727,66 @@ void nl80211_notify_dev_rename(struct cfg80211_registered_device *rdev)
 	genlmsg_multicast(msg, 0, nl80211_config_mcgrp.id, GFP_KERNEL);
 }
 
+static int nl80211_send_scan_donemsg(struct sk_buff *msg,
+				    struct cfg80211_registered_device *rdev,
+				    struct net_device *netdev,
+				    u32 pid, u32 seq, int flags,
+				    u32 cmd)
+{
+	void *hdr;
+
+	hdr = nl80211hdr_put(msg, pid, seq, flags, cmd);
+	if (!hdr)
+		return -1;
+
+	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, rdev->idx);
+	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex);
+
+	/* XXX: we should probably bounce back the request? */
+
+	return genlmsg_end(msg, hdr);
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+void nl80211_send_scan_done(struct cfg80211_registered_device *rdev,
+			    struct net_device *netdev)
+{
+	struct sk_buff *msg;
+
+	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	if (nl80211_send_scan_donemsg(msg, rdev, netdev, 0, 0, 0,
+				      NL80211_CMD_NEW_SCAN_RESULTS) < 0) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	genlmsg_multicast(msg, 0, nl80211_scan_mcgrp.id, GFP_KERNEL);
+}
+
+void nl80211_send_scan_aborted(struct cfg80211_registered_device *rdev,
+			       struct net_device *netdev)
+{
+	struct sk_buff *msg;
+
+	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	if (nl80211_send_scan_donemsg(msg, rdev, netdev, 0, 0, 0,
+				      NL80211_CMD_SCAN_ABORTED) < 0) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	genlmsg_multicast(msg, 0, nl80211_scan_mcgrp.id, GFP_KERNEL);
+}
+
 /* initialisation/exit functions */
 
 int nl80211_init(void)
@@ -2488,6 +2807,10 @@ int nl80211_init(void)
 	if (err)
 		goto err_out;
 
+	err = genl_register_mc_group(&nl80211_fam, &nl80211_scan_mcgrp);
+	if (err)
+		goto err_out;
+
 	return 0;
  err_out:
 	genl_unregister_family(&nl80211_fam);
diff --git a/net/wireless/nl80211.h b/net/wireless/nl80211.h
index f3ea5c029aee..b565a5f84e97 100644
--- a/net/wireless/nl80211.h
+++ b/net/wireless/nl80211.h
@@ -7,6 +7,10 @@
 extern int nl80211_init(void);
 extern void nl80211_exit(void);
 extern void nl80211_notify_dev_rename(struct cfg80211_registered_device *rdev);
+extern void nl80211_send_scan_done(struct cfg80211_registered_device *rdev,
+				   struct net_device *netdev);
+extern void nl80211_send_scan_aborted(struct cfg80211_registered_device *rdev,
+				      struct net_device *netdev);
 #else
 static inline int nl80211_init(void)
 {
@@ -19,6 +23,10 @@ static inline void nl80211_notify_dev_rename(
 	struct cfg80211_registered_device *rdev)
 {
 }
+static inline void
+nl80211_send_scan_done(struct cfg80211_registered_device *rdev,
+		       struct net_device *netdev)
+{}
 #endif /* CONFIG_NL80211 */
 
 #endif /* __NET_WIRELESS_NL80211_H */
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
new file mode 100644
index 000000000000..009d12810c55
--- /dev/null
+++ b/net/wireless/scan.c
@@ -0,0 +1,807 @@
+/*
+ * 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);
+	kfree(bss);
+}
+
+/* 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 (compare_ether_addr(a->bssid, bssid))
+		return false;
+
+	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)
+{
+	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_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.signal_type = res->pub.signal_type;
+		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, enum cfg80211_signal_type sigtype,
+			  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(sigtype == 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_type = sigtype;
+	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;
+
+	/* 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);
+
+#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 char *
+ieee80211_bss(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;
+	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 (bss->pub.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_INVALID;
+		switch (bss->pub.signal_type) {
+		case CFG80211_SIGNAL_TYPE_MBM:
+			iwe.u.qual.level = bss->pub.signal / 100;
+			iwe.u.qual.updated |= IW_QUAL_DBM;
+			break;
+		case CFG80211_SIGNAL_TYPE_UNSPEC:
+			iwe.u.qual.level = 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: %dms ago",
+			jiffies_to_msecs(jiffies - 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(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