[NL80211]: add netlink interface to cfg80211

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

7 files changed, 653 insertions, 2 deletions

diff --git a/net/mac80211/ieee80211_cfg.c b/net/mac80211/ieee80211_cfg.c
index b1c13bc9c3ca..d6fc55cc8ad4 100644
--- a/net/mac80211/ieee80211_cfg.c
+++ b/net/mac80211/ieee80211_cfg.c
@@ -14,7 +14,7 @@
 #include "ieee80211_cfg.h"
 
 static int ieee80211_add_iface(struct wiphy *wiphy, char *name,
-                               unsigned int type)
+                               enum nl80211_iftype type)
 {
         struct ieee80211_local *local = wiphy_priv(wiphy);
         int itype;
diff --git a/net/wireless/Kconfig b/net/wireless/Kconfig
index a228d56a91b8..6291f13bba09 100644
--- a/net/wireless/Kconfig
+++ b/net/wireless/Kconfig
@@ -1,6 +1,19 @@
 config CFG80211
         tristate "Improved wireless configuration API"
 
+config NL80211
+        bool "nl80211 new netlink interface support"
+        depends CFG80211
+        default y
+        ---help---
+         This option turns on the new netlink interface
+         (nl80211) support in cfg80211.
+
+         If =n, drivers using mac80211 will be configured via
+         wireless extension support provided by that subsystem.
+
+         If unsure, say Y.
+
 config WIRELESS_EXT
         bool "Wireless extensions"
         default n
@@ -10,7 +23,9 @@ config WIRELESS_EXT
 
           Wireless extensions will be replaced by cfg80211 and
           will be required only by legacy drivers that implement
-          wireless extension handlers.
+          wireless extension handlers. This option does not
+          affect the wireless-extension backward compatibility
+          code in cfg80211.
 
           Say N (if you can) unless you know you need wireless
           extensions for external modules.
diff --git a/net/wireless/Makefile b/net/wireless/Makefile
index 092116e390b6..65710a42e5a7 100644
--- a/net/wireless/Makefile
+++ b/net/wireless/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_WIRELESS_EXT) += wext.o
 obj-$(CONFIG_CFG80211) += cfg80211.o
 
 cfg80211-y += core.o sysfs.o radiotap.o
+cfg80211-$(CONFIG_NL80211) += nl80211.o
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 9771451eae21..febc33bc9c09 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -16,6 +16,7 @@
 #include <net/genetlink.h>
 #include <net/cfg80211.h>
 #include <net/wireless.h>
+#include "nl80211.h"
 #include "core.h"
 #include "sysfs.h"
 
@@ -36,6 +37,146 @@ static int wiphy_counter;
 /* for debugfs */
 static struct dentry *ieee80211_debugfs_dir;
 
+/* requires cfg80211_drv_mutex to be held! */
+static struct cfg80211_registered_device *cfg80211_drv_by_wiphy(int wiphy)
+{
+        struct cfg80211_registered_device *result = NULL, *drv;
+
+        list_for_each_entry(drv, &cfg80211_drv_list, list) {
+                if (drv->idx == wiphy) {
+                        result = drv;
+                        break;
+                }
+        }
+
+        return result;
+}
+
+/* requires cfg80211_drv_mutex to be held! */
+static struct cfg80211_registered_device *
+__cfg80211_drv_from_info(struct genl_info *info)
+{
+        int ifindex;
+        struct cfg80211_registered_device *bywiphy = NULL, *byifidx = NULL;
+        struct net_device *dev;
+        int err = -EINVAL;
+
+        if (info->attrs[NL80211_ATTR_WIPHY]) {
+                bywiphy = cfg80211_drv_by_wiphy(
+                                nla_get_u32(info->attrs[NL80211_ATTR_WIPHY]));
+                err = -ENODEV;
+        }
+
+        if (info->attrs[NL80211_ATTR_IFINDEX]) {
+                ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
+                dev = dev_get_by_index(&init_net, ifindex);
+                if (dev) {
+                        if (dev->ieee80211_ptr)
+                                byifidx =
+                                        wiphy_to_dev(dev->ieee80211_ptr->wiphy);
+                        dev_put(dev);
+                }
+                err = -ENODEV;
+        }
+
+        if (bywiphy && byifidx) {
+                if (bywiphy != byifidx)
+                        return ERR_PTR(-EINVAL);
+                else
+                        return bywiphy; /* == byifidx */
+        }
+        if (bywiphy)
+                return bywiphy;
+
+        if (byifidx)
+                return byifidx;
+
+        return ERR_PTR(err);
+}
+
+struct cfg80211_registered_device *
+cfg80211_get_dev_from_info(struct genl_info *info)
+{
+        struct cfg80211_registered_device *drv;
+
+        mutex_lock(&cfg80211_drv_mutex);
+        drv = __cfg80211_drv_from_info(info);
+
+        /* if it is not an error we grab the lock on
+         * it to assure it won't be going away while
+         * we operate on it */
+        if (!IS_ERR(drv))
+                mutex_lock(&drv->mtx);
+
+        mutex_unlock(&cfg80211_drv_mutex);
+
+        return drv;
+}
+
+struct cfg80211_registered_device *
+cfg80211_get_dev_from_ifindex(int ifindex)
+{
+        struct cfg80211_registered_device *drv = ERR_PTR(-ENODEV);
+        struct net_device *dev;
+
+        mutex_lock(&cfg80211_drv_mutex);
+        dev = dev_get_by_index(&init_net, ifindex);
+        if (!dev)
+                goto out;
+        if (dev->ieee80211_ptr) {
+                drv = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
+                mutex_lock(&drv->mtx);
+        } else
+                drv = ERR_PTR(-ENODEV);
+        dev_put(dev);
+ out:
+        mutex_unlock(&cfg80211_drv_mutex);
+        return drv;
+}
+
+void cfg80211_put_dev(struct cfg80211_registered_device *drv)
+{
+        BUG_ON(IS_ERR(drv));
+        mutex_unlock(&drv->mtx);
+}
+
+int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
+                        char *newname)
+{
+        int idx, taken = -1, result, digits;
+
+        /* prohibit calling the thing phy%d when %d is not its number */
+        sscanf(newname, PHY_NAME "%d%n", &idx, &taken);
+        if (taken == strlen(newname) && idx != rdev->idx) {
+                /* count number of places needed to print idx */
+                digits = 1;
+                while (idx /= 10)
+                        digits++;
+                /*
+                 * deny the name if it is phy<idx> where <idx> is printed
+                 * without leading zeroes. taken == strlen(newname) here
+                 */
+                if (taken == strlen(PHY_NAME) + digits)
+                        return -EINVAL;
+        }
+
+        /* this will check for collisions */
+        result = device_rename(&rdev->wiphy.dev, newname);
+        if (result)
+                return result;
+
+        if (!debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
+                            rdev->wiphy.debugfsdir,
+                            rdev->wiphy.debugfsdir->d_parent,
+                            newname))
+                printk(KERN_ERR "cfg80211: failed to rename debugfs dir to %s!\n",
+                       newname);
+
+        nl80211_notify_dev_rename(rdev);
+
+        return 0;
+}
+
 /* exported functions */
 
 struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
@@ -204,10 +345,16 @@ static int cfg80211_init(void)
         if (err)
                 goto out_fail_notifier;
 
+        err = nl80211_init();
+        if (err)
+                goto out_fail_nl80211;
+
         ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);
 
         return 0;
 
+out_fail_nl80211:
+        unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 out_fail_notifier:
         wiphy_sysfs_exit();
 out_fail_sysfs:
@@ -218,6 +365,7 @@ subsys_initcall(cfg80211_init);
 static void cfg80211_exit(void)
 {
         debugfs_remove(ieee80211_debugfs_dir);
+        nl80211_exit();
         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
         wiphy_sysfs_exit();
 }
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 158db1edb92a..eb0f846b40df 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -43,7 +43,39 @@ struct cfg80211_registered_device *wiphy_to_dev(struct wiphy *wiphy)
 extern struct mutex cfg80211_drv_mutex;
 extern struct list_head cfg80211_drv_list;
 
+/*
+ * This function returns a pointer to the driver
+ * that the genl_info item that is passed refers to.
+ * If successful, it returns non-NULL and also locks
+ * the driver's mutex!
+ *
+ * This means that you need to call cfg80211_put_dev()
+ * before being allowed to acquire &cfg80211_drv_mutex!
+ *
+ * This is necessary because we need to lock the global
+ * mutex to get an item off the list safely, and then
+ * we lock the drv mutex so it doesn't go away under us.
+ *
+ * We don't want to keep cfg80211_drv_mutex locked
+ * for all the time in order to allow requests on
+ * other interfaces to go through at the same time.
+ *
+ * The result of this can be a PTR_ERR and hence must
+ * be checked with IS_ERR() for errors.
+ */
+extern struct cfg80211_registered_device *
+cfg80211_get_dev_from_info(struct genl_info *info);
+
+/* identical to cfg80211_get_dev_from_info but only operate on ifindex */
+extern struct cfg80211_registered_device *
+cfg80211_get_dev_from_ifindex(int ifindex);
+
+extern void cfg80211_put_dev(struct cfg80211_registered_device *drv);
+
 /* free object */
 extern void cfg80211_dev_free(struct cfg80211_registered_device *drv);
 
+extern int cfg80211_dev_rename(struct cfg80211_registered_device *drv,
+                               char *newname);
+
 #endif /* __NET_WIRELESS_CORE_H */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
new file mode 100644
index 000000000000..48b0d453e4e1
--- /dev/null
+++ b/net/wireless/nl80211.c
@@ -0,0 +1,431 @@
+/*
+ * This is the new netlink-based wireless configuration interface.
+ *
+ * Copyright 2006, 2007 Johannes Berg <johannes@sipsolutions.net>
+ */
+
+#include <linux/if.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/if_ether.h>
+#include <linux/ieee80211.h>
+#include <linux/nl80211.h>
+#include <linux/rtnetlink.h>
+#include <linux/netlink.h>
+#include <net/genetlink.h>
+#include <net/cfg80211.h>
+#include "core.h"
+#include "nl80211.h"
+
+/* the netlink family */
+static struct genl_family nl80211_fam = {
+        .id = GENL_ID_GENERATE, /* don't bother with a hardcoded ID */
+        .name = "nl80211",      /* have users key off the name instead */
+        .hdrsize = 0,           /* no private header */
+        .version = 1,           /* no particular meaning now */
+        .maxattr = NL80211_ATTR_MAX,
+};
+
+/* internal helper: get drv and dev */
+static int get_drv_dev_by_info_ifindex(struct genl_info *info,
+                                       struct cfg80211_registered_device **drv,
+                                       struct net_device **dev)
+{
+        int ifindex;
+
+        if (!info->attrs[NL80211_ATTR_IFINDEX])
+                return -EINVAL;
+
+        ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
+        *dev = dev_get_by_index(&init_net, ifindex);
+        if (!*dev)
+                return -ENODEV;
+
+        *drv = cfg80211_get_dev_from_ifindex(ifindex);
+        if (IS_ERR(*drv)) {
+                dev_put(*dev);
+                return PTR_ERR(*drv);
+        }
+
+        return 0;
+}
+
+/* policy for the attributes */
+static struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] __read_mostly = {
+        [NL80211_ATTR_WIPHY] = { .type = NLA_U32 },
+        [NL80211_ATTR_WIPHY_NAME] = { .type = NLA_NUL_STRING,
+                                      .len = BUS_ID_SIZE-1 },
+
+        [NL80211_ATTR_IFTYPE] = { .type = NLA_U32 },
+        [NL80211_ATTR_IFINDEX] = { .type = NLA_U32 },
+        [NL80211_ATTR_IFNAME] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ-1 },
+};
+
+/* message building helper */
+static inline void *nl80211hdr_put(struct sk_buff *skb, u32 pid, u32 seq,
+                                   int flags, u8 cmd)
+{
+        /* since there is no private header just add the generic one */
+        return genlmsg_put(skb, pid, seq, &nl80211_fam, flags, cmd);
+}
+
+/* netlink command implementations */
+
+static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
+                              struct cfg80211_registered_device *dev)
+{
+        void *hdr;
+
+        hdr = nl80211hdr_put(msg, pid, seq, flags, NL80211_CMD_NEW_WIPHY);
+        if (!hdr)
+                return -1;
+
+        NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, dev->idx);
+        NLA_PUT_STRING(msg, NL80211_ATTR_WIPHY_NAME, wiphy_name(&dev->wiphy));
+        return genlmsg_end(msg, hdr);
+
+ nla_put_failure:
+        return genlmsg_cancel(msg, hdr);
+}
+
+static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)
+{
+        int idx = 0;
+        int start = cb->args[0];
+        struct cfg80211_registered_device *dev;
+
+        mutex_lock(&cfg80211_drv_mutex);
+        list_for_each_entry(dev, &cfg80211_drv_list, list) {
+                if (++idx < start)
+                        continue;
+                if (nl80211_send_wiphy(skb, NETLINK_CB(cb->skb).pid,
+                                       cb->nlh->nlmsg_seq, NLM_F_MULTI,
+                                       dev) < 0)
+                        break;
+        }
+        mutex_unlock(&cfg80211_drv_mutex);
+
+        cb->args[0] = idx;
+
+        return skb->len;
+}
+
+static int nl80211_get_wiphy(struct sk_buff *skb, struct genl_info *info)
+{
+        struct sk_buff *msg;
+        struct cfg80211_registered_device *dev;
+
+        dev = cfg80211_get_dev_from_info(info);
+        if (IS_ERR(dev))
+                return PTR_ERR(dev);
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+        if (!msg)
+                goto out_err;
+
+        if (nl80211_send_wiphy(msg, info->snd_pid, info->snd_seq, 0, dev) < 0)
+                goto out_free;
+
+        cfg80211_put_dev(dev);
+
+        return genlmsg_unicast(msg, info->snd_pid);
+
+ out_free:
+        nlmsg_free(msg);
+ out_err:
+        cfg80211_put_dev(dev);
+        return -ENOBUFS;
+}
+
+static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
+{
+        struct cfg80211_registered_device *rdev;
+        int result;
+
+        if (!info->attrs[NL80211_ATTR_WIPHY_NAME])
+                return -EINVAL;
+
+        rdev = cfg80211_get_dev_from_info(info);
+        if (IS_ERR(rdev))
+                return PTR_ERR(rdev);
+
+        result = cfg80211_dev_rename(rdev, nla_data(info->attrs[NL80211_ATTR_WIPHY_NAME]));
+
+        cfg80211_put_dev(rdev);
+        return result;
+}
+
+
+static int nl80211_send_iface(struct sk_buff *msg, u32 pid, u32 seq, int flags,
+                              struct net_device *dev)
+{
+        void *hdr;
+
+        hdr = nl80211hdr_put(msg, pid, seq, flags, NL80211_CMD_NEW_INTERFACE);
+        if (!hdr)
+                return -1;
+
+        NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, dev->ifindex);
+        NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, dev->name);
+        /* TODO: interface type */
+        return genlmsg_end(msg, hdr);
+
+ nla_put_failure:
+        return genlmsg_cancel(msg, hdr);
+}
+
+static int nl80211_dump_interface(struct sk_buff *skb, struct netlink_callback *cb)
+{
+        int wp_idx = 0;
+        int if_idx = 0;
+        int wp_start = cb->args[0];
+        int if_start = cb->args[1];
+        struct cfg80211_registered_device *dev;
+        struct wireless_dev *wdev;
+
+        mutex_lock(&cfg80211_drv_mutex);
+        list_for_each_entry(dev, &cfg80211_drv_list, list) {
+                if (++wp_idx < wp_start)
+                        continue;
+                if_idx = 0;
+
+                mutex_lock(&dev->devlist_mtx);
+                list_for_each_entry(wdev, &dev->netdev_list, list) {
+                        if (++if_idx < if_start)
+                                continue;
+                        if (nl80211_send_iface(skb, NETLINK_CB(cb->skb).pid,
+                                               cb->nlh->nlmsg_seq, NLM_F_MULTI,
+                                               wdev->netdev) < 0)
+                                break;
+                }
+                mutex_unlock(&dev->devlist_mtx);
+        }
+        mutex_unlock(&cfg80211_drv_mutex);
+
+        cb->args[0] = wp_idx;
+        cb->args[1] = if_idx;
+
+        return skb->len;
+}
+
+static int nl80211_get_interface(struct sk_buff *skb, struct genl_info *info)
+{
+        struct sk_buff *msg;
+        struct cfg80211_registered_device *dev;
+        struct net_device *netdev;
+        int err;
+
+        err = get_drv_dev_by_info_ifindex(info, &dev, &netdev);
+        if (err)
+                return err;
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+        if (!msg)
+                goto out_err;
+
+        if (nl80211_send_iface(msg, info->snd_pid, info->snd_seq, 0, netdev) < 0)
+                goto out_free;
+
+        dev_put(netdev);
+        cfg80211_put_dev(dev);
+
+        return genlmsg_unicast(msg, info->snd_pid);
+
+ out_free:
+        nlmsg_free(msg);
+ out_err:
+        dev_put(netdev);
+        cfg80211_put_dev(dev);
+        return -ENOBUFS;
+}
+
+static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info)
+{
+        struct cfg80211_registered_device *drv;
+        int err, ifindex;
+        enum nl80211_iftype type;
+        struct net_device *dev;
+
+        if (info->attrs[NL80211_ATTR_IFTYPE]) {
+                type = nla_get_u32(info->attrs[NL80211_ATTR_IFTYPE]);
+                if (type > NL80211_IFTYPE_MAX)
+                        return -EINVAL;
+        } else
+                return -EINVAL;
+
+        err = get_drv_dev_by_info_ifindex(info, &drv, &dev);
+        if (err)
+                return err;
+        ifindex = dev->ifindex;
+        dev_put(dev);
+
+        if (!drv->ops->change_virtual_intf) {
+                err = -EOPNOTSUPP;
+                goto unlock;
+        }
+
+        rtnl_lock();
+        err = drv->ops->change_virtual_intf(&drv->wiphy, ifindex, type);
+        rtnl_unlock();
+
+ unlock:
+        cfg80211_put_dev(drv);
+        return err;
+}
+
+static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info)
+{
+        struct cfg80211_registered_device *drv;
+        int err;
+        enum nl80211_iftype type = NL80211_IFTYPE_UNSPECIFIED;
+
+        if (!info->attrs[NL80211_ATTR_IFNAME])
+                return -EINVAL;
+
+        if (info->attrs[NL80211_ATTR_IFTYPE]) {
+                type = nla_get_u32(info->attrs[NL80211_ATTR_IFTYPE]);
+                if (type > NL80211_IFTYPE_MAX)
+                        return -EINVAL;
+        }
+
+        drv = cfg80211_get_dev_from_info(info);
+        if (IS_ERR(drv))
+                return PTR_ERR(drv);
+
+        if (!drv->ops->add_virtual_intf) {
+                err = -EOPNOTSUPP;
+                goto unlock;
+        }
+
+        rtnl_lock();
+        err = drv->ops->add_virtual_intf(&drv->wiphy,
+                nla_data(info->attrs[NL80211_ATTR_IFNAME]), type);
+        rtnl_unlock();
+
+ unlock:
+        cfg80211_put_dev(drv);
+        return err;
+}
+
+static int nl80211_del_interface(struct sk_buff *skb, struct genl_info *info)
+{
+        struct cfg80211_registered_device *drv;
+        int ifindex, err;
+        struct net_device *dev;
+
+        err = get_drv_dev_by_info_ifindex(info, &drv, &dev);
+        if (err)
+                return err;
+        ifindex = dev->ifindex;
+        dev_put(dev);
+
+        if (!drv->ops->del_virtual_intf) {
+                err = -EOPNOTSUPP;
+                goto out;
+        }
+
+        rtnl_lock();
+        err = drv->ops->del_virtual_intf(&drv->wiphy, ifindex);
+        rtnl_unlock();
+
+ out:
+        cfg80211_put_dev(drv);
+        return err;
+}
+
+static struct genl_ops nl80211_ops[] = {
+        {
+                .cmd = NL80211_CMD_GET_WIPHY,
+                .doit = nl80211_get_wiphy,
+                .dumpit = nl80211_dump_wiphy,
+                .policy = nl80211_policy,
+                /* can be retrieved by unprivileged users */
+        },
+        {
+                .cmd = NL80211_CMD_SET_WIPHY,
+                .doit = nl80211_set_wiphy,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+        },
+        {
+                .cmd = NL80211_CMD_GET_INTERFACE,
+                .doit = nl80211_get_interface,
+                .dumpit = nl80211_dump_interface,
+                .policy = nl80211_policy,
+                /* can be retrieved by unprivileged users */
+        },
+        {
+                .cmd = NL80211_CMD_SET_INTERFACE,
+                .doit = nl80211_set_interface,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+        },
+        {
+                .cmd = NL80211_CMD_NEW_INTERFACE,
+                .doit = nl80211_new_interface,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+        },
+        {
+                .cmd = NL80211_CMD_DEL_INTERFACE,
+                .doit = nl80211_del_interface,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+        },
+};
+
+/* multicast groups */
+static struct genl_multicast_group nl80211_config_mcgrp = {
+        .name = "config",
+};
+
+/* notification functions */
+
+void nl80211_notify_dev_rename(struct cfg80211_registered_device *rdev)
+{
+        struct sk_buff *msg;
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+        if (!msg)
+                return;
+
+        if (nl80211_send_wiphy(msg, 0, 0, 0, rdev) < 0) {
+                nlmsg_free(msg);
+                return;
+        }
+
+        genlmsg_multicast(msg, 0, nl80211_config_mcgrp.id, GFP_KERNEL);
+}
+
+/* initialisation/exit functions */
+
+int nl80211_init(void)
+{
+        int err, i;
+
+        err = genl_register_family(&nl80211_fam);
+        if (err)
+                return err;
+
+        for (i = 0; i < ARRAY_SIZE(nl80211_ops); i++) {
+                err = genl_register_ops(&nl80211_fam, &nl80211_ops[i]);
+                if (err)
+                        goto err_out;
+        }
+
+        err = genl_register_mc_group(&nl80211_fam, &nl80211_config_mcgrp);
+        if (err)
+                goto err_out;
+
+        return 0;
+ err_out:
+        genl_unregister_family(&nl80211_fam);
+        return err;
+}
+
+void nl80211_exit(void)
+{
+        genl_unregister_family(&nl80211_fam);
+}
diff --git a/net/wireless/nl80211.h b/net/wireless/nl80211.h
new file mode 100644
index 000000000000..f3ea5c029aee
--- /dev/null
+++ b/net/wireless/nl80211.h
@@ -0,0 +1,24 @@
+#ifndef __NET_WIRELESS_NL80211_H
+#define __NET_WIRELESS_NL80211_H
+
+#include "core.h"
+
+#ifdef CONFIG_NL80211
+extern int nl80211_init(void);
+extern void nl80211_exit(void);
+extern void nl80211_notify_dev_rename(struct cfg80211_registered_device *rdev);
+#else
+static inline int nl80211_init(void)
+{
+        return 0;
+}
+static inline void nl80211_exit(void)
+{
+}
+static inline void nl80211_notify_dev_rename(
+        struct cfg80211_registered_device *rdev)
+{
+}
+#endif /* CONFIG_NL80211 */
+
+#endif /* __NET_WIRELESS_NL80211_H */