cfg80211/nl80211: add IBSS API

This adds IBSS API along with (preliminary) wext handlers.
The wext handlers can only do IBSS so you need to call them
from your own wext handlers if the mode is IBSS.

The nl80211 API requires
 * an SSID
 * a channel (frequency) for the case that a new IBSS
   has to be created

It optionally supports
 * a flag to fix the channel
 * a fixed BSSID

The cfg80211 code also takes care to leave the IBSS before
the netdev is set down. If wireless extensions are used, it
also caches values when the interface is down and instructs
the driver to join when the interface is set up.

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

1 files changed, 170 insertions, 12 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d2cfde659e76..16f86356ac97 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -116,6 +116,7 @@ static struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] __read_mostly = {
                                 .len = IEEE80211_MAX_SSID_LEN },
         [NL80211_ATTR_AUTH_TYPE] = { .type = NLA_U32 },
         [NL80211_ATTR_REASON_CODE] = { .type = NLA_U16 },
+        [NL80211_ATTR_FREQ_FIXED] = { .type = NLA_FLAG },
 };
 
 /* IE validation */
@@ -322,6 +323,7 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
         CMD(assoc, ASSOCIATE);
         CMD(deauth, DEAUTHENTICATE);
         CMD(disassoc, DISASSOCIATE);
+        CMD(join_ibss, JOIN_IBSS);
 
 #undef CMD
         nla_nest_end(msg, nl_cmds);
@@ -668,7 +670,7 @@ static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info)
         struct cfg80211_registered_device *drv;
         struct vif_params params;
         int err, ifindex;
-        enum nl80211_iftype type;
+        enum nl80211_iftype otype, ntype;
         struct net_device *dev;
         u32 _flags, *flags = NULL;
         bool change = false;
@@ -682,30 +684,27 @@ static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info)
                 goto unlock_rtnl;
 
         ifindex = dev->ifindex;
-        type = dev->ieee80211_ptr->iftype;
+        otype = ntype = dev->ieee80211_ptr->iftype;
         dev_put(dev);
 
         if (info->attrs[NL80211_ATTR_IFTYPE]) {
-                enum nl80211_iftype ntype;
-
                 ntype = nla_get_u32(info->attrs[NL80211_ATTR_IFTYPE]);
-                if (type != ntype)
+                if (otype != ntype)
                         change = true;
-                type = ntype;
-                if (type > NL80211_IFTYPE_MAX) {
+                if (ntype > NL80211_IFTYPE_MAX) {
                         err = -EINVAL;
                         goto unlock;
                 }
         }
 
         if (!drv->ops->change_virtual_intf ||
-            !(drv->wiphy.interface_modes & (1 << type))) {
+            !(drv->wiphy.interface_modes & (1 << ntype))) {
                 err = -EOPNOTSUPP;
                 goto unlock;
         }
 
         if (info->attrs[NL80211_ATTR_MESH_ID]) {
-                if (type != NL80211_IFTYPE_MESH_POINT) {
+                if (ntype != NL80211_IFTYPE_MESH_POINT) {
                         err = -EINVAL;
                         goto unlock;
                 }
@@ -715,7 +714,7 @@ static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info)
         }
 
         if (info->attrs[NL80211_ATTR_MNTR_FLAGS]) {
-                if (type != NL80211_IFTYPE_MONITOR) {
+                if (ntype != NL80211_IFTYPE_MONITOR) {
                         err = -EINVAL;
                         goto unlock;
                 }
@@ -730,12 +729,17 @@ static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info)
 
         if (change)
                 err = drv->ops->change_virtual_intf(&drv->wiphy, ifindex,
-                                                    type, flags, &params);
+                                                    ntype, flags, &params);
         else
                 err = 0;
 
         dev = __dev_get_by_index(&init_net, ifindex);
-        WARN_ON(!dev || (!err && dev->ieee80211_ptr->iftype != type));
+        WARN_ON(!dev || (!err && dev->ieee80211_ptr->iftype != ntype));
+
+        if (dev && !err && (ntype != otype)) {
+                if (otype == NL80211_IFTYPE_ADHOC)
+                        cfg80211_clear_ibss(dev);
+        }
 
  unlock:
         cfg80211_put_dev(drv);
@@ -3052,6 +3056,114 @@ unlock_rtnl:
         return err;
 }
 
+static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
+{
+        struct cfg80211_registered_device *drv;
+        struct net_device *dev;
+        struct cfg80211_ibss_params ibss;
+        struct wiphy *wiphy;
+        int err;
+
+        if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
+                return -EINVAL;
+
+        if (!info->attrs[NL80211_ATTR_WIPHY_FREQ] ||
+            !info->attrs[NL80211_ATTR_SSID] ||
+            !nla_len(info->attrs[NL80211_ATTR_SSID]))
+                return -EINVAL;
+
+        rtnl_lock();
+
+        err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev);
+        if (err)
+                goto unlock_rtnl;
+
+        if (!drv->ops->join_ibss) {
+                err = -EOPNOTSUPP;
+                goto out;
+        }
+
+        if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_ADHOC) {
+                err = -EOPNOTSUPP;
+                goto out;
+        }
+
+        if (!netif_running(dev)) {
+                err = -ENETDOWN;
+                goto out;
+        }
+
+        wiphy = &drv->wiphy;
+        memset(&ibss, 0, sizeof(ibss));
+
+        if (info->attrs[NL80211_ATTR_MAC])
+                ibss.bssid = nla_data(info->attrs[NL80211_ATTR_MAC]);
+        ibss.ssid = nla_data(info->attrs[NL80211_ATTR_SSID]);
+        ibss.ssid_len = nla_len(info->attrs[NL80211_ATTR_SSID]);
+
+        if (info->attrs[NL80211_ATTR_IE]) {
+                ibss.ie = nla_data(info->attrs[NL80211_ATTR_IE]);
+                ibss.ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);
+        }
+
+        ibss.channel = ieee80211_get_channel(wiphy,
+                nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]));
+        if (!ibss.channel ||
+            ibss.channel->flags & IEEE80211_CHAN_NO_IBSS ||
+            ibss.channel->flags & IEEE80211_CHAN_DISABLED) {
+                err = -EINVAL;
+                goto out;
+        }
+
+        ibss.channel_fixed = !!info->attrs[NL80211_ATTR_FREQ_FIXED];
+
+        err = cfg80211_join_ibss(drv, dev, &ibss);
+
+out:
+        cfg80211_put_dev(drv);
+        dev_put(dev);
+unlock_rtnl:
+        rtnl_unlock();
+        return err;
+}
+
+static int nl80211_leave_ibss(struct sk_buff *skb, struct genl_info *info)
+{
+        struct cfg80211_registered_device *drv;
+        struct net_device *dev;
+        int err;
+
+        rtnl_lock();
+
+        err = get_drv_dev_by_info_ifindex(info->attrs, &drv, &dev);
+        if (err)
+                goto unlock_rtnl;
+
+        if (!drv->ops->leave_ibss) {
+                err = -EOPNOTSUPP;
+                goto out;
+        }
+
+        if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_ADHOC) {
+                err = -EOPNOTSUPP;
+                goto out;
+        }
+
+        if (!netif_running(dev)) {
+                err = -ENETDOWN;
+                goto out;
+        }
+
+        err = cfg80211_leave_ibss(drv, dev);
+
+out:
+        cfg80211_put_dev(drv);
+        dev_put(dev);
+unlock_rtnl:
+        rtnl_unlock();
+        return err;
+}
+
 static struct genl_ops nl80211_ops[] = {
         {
                 .cmd = NL80211_CMD_GET_WIPHY,
@@ -3253,6 +3365,18 @@ static struct genl_ops nl80211_ops[] = {
                 .policy = nl80211_policy,
                 .flags = GENL_ADMIN_PERM,
         },
+        {
+                .cmd = NL80211_CMD_JOIN_IBSS,
+                .doit = nl80211_join_ibss,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+        },
+        {
+                .cmd = NL80211_CMD_LEAVE_IBSS,
+                .doit = nl80211_leave_ibss,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+        },
 };
 static struct genl_multicast_group nl80211_mlme_mcgrp = {
         .name = "mlme",
@@ -3466,6 +3590,40 @@ void nl80211_send_disassoc(struct cfg80211_registered_device *rdev,
                                 NL80211_CMD_DISASSOCIATE);
 }
 
+void nl80211_send_ibss_bssid(struct cfg80211_registered_device *rdev,
+                             struct net_device *netdev, const u8 *bssid,
+                             gfp_t gfp)
+{
+        struct sk_buff *msg;
+        void *hdr;
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, gfp);
+        if (!msg)
+                return;
+
+        hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_JOIN_IBSS);
+        if (!hdr) {
+                nlmsg_free(msg);
+                return;
+        }
+
+        NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx);
+        NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex);
+        NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, bssid);
+
+        if (genlmsg_end(msg, hdr) < 0) {
+                nlmsg_free(msg);
+                return;
+        }
+
+        genlmsg_multicast(msg, 0, nl80211_mlme_mcgrp.id, gfp);
+        return;
+
+ nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+        nlmsg_free(msg);
+}
+
 void nl80211_michael_mic_failure(struct cfg80211_registered_device *rdev,
                                  struct net_device *netdev, const u8 *addr,
                                  enum nl80211_key_type key_type, int key_id,