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