nl80211: Parse channel type attribute in an ibss join request

Prepare cfg80211 for IBSS HT:
 * extend cfg80211 ibss struct with channel_type
 * Check if extension channel can be used
 * Export can_beacon_sec_chan for use in mac80211 (will be called
   from ibss.c later).

Signed-off-by: Alexander Simon <an.alexsimon@googlemail.com>
[siwu@hrz.tu-chemnitz.de: Updates]
* fix cfg80211_can_beacon_ext_chan comment
* remove implicit channel_type enum assumptions
* remove radar channel flags check
* add HT IBSS feature flag
* reword commit message

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 37 insertions, 7 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 17cd0c04d139..2fcfe0993ca2 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -6,6 +6,7 @@
  * Copyright 2009       Johannes Berg <johannes@sipsolutions.net>
  */
 
+#include <linux/export.h>
 #include <net/cfg80211.h>
 #include "core.h"
 
@@ -44,9 +45,9 @@ rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
         return chan;
 }
 
-static bool can_beacon_sec_chan(struct wiphy *wiphy,
-                                struct ieee80211_channel *chan,
-                                enum nl80211_channel_type channel_type)
+int cfg80211_can_beacon_sec_chan(struct wiphy *wiphy,
+                                  struct ieee80211_channel *chan,
+                                  enum nl80211_channel_type channel_type)
 {
         struct ieee80211_channel *sec_chan;
         int diff;
@@ -75,6 +76,7 @@ static bool can_beacon_sec_chan(struct wiphy *wiphy,
 
         return true;
 }
+EXPORT_SYMBOL(cfg80211_can_beacon_sec_chan);
 
 int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
                       struct wireless_dev *wdev, int freq,
@@ -109,8 +111,8 @@ int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
                 switch (channel_type) {
                 case NL80211_CHAN_HT40PLUS:
                 case NL80211_CHAN_HT40MINUS:
-                        if (!can_beacon_sec_chan(&rdev->wiphy, chan,
-                                                 channel_type)) {
+                        if (!cfg80211_can_beacon_sec_chan(&rdev->wiphy, chan,
+                                                          channel_type)) {
                                 printk(KERN_DEBUG
                                        "cfg80211: Secondary channel not "
                                        "allowed to initiate communication\n");
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 8a9b4d817ae6..ba439664c2e0 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4682,13 +4682,41 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
                 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 (info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE]) {
+                enum nl80211_channel_type channel_type;
+
+                channel_type = nla_get_u32(
+                                info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE]);
+                if (channel_type != NL80211_CHAN_NO_HT &&
+                    channel_type != NL80211_CHAN_HT20 &&
+                    channel_type != NL80211_CHAN_HT40MINUS &&
+                    channel_type != NL80211_CHAN_HT40PLUS)
+                        return -EINVAL;
+
+                if (channel_type != NL80211_CHAN_NO_HT &&
+                    !(wiphy->features & NL80211_FEATURE_HT_IBSS))
+                        return -EINVAL;
+
+                ibss.channel_type = channel_type;
+        } else {
+                ibss.channel_type = NL80211_CHAN_NO_HT;
+        }
+
+        ibss.channel = rdev_freq_to_chan(rdev,
+                nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]),
+                ibss.channel_type);
         if (!ibss.channel ||
             ibss.channel->flags & IEEE80211_CHAN_NO_IBSS ||
             ibss.channel->flags & IEEE80211_CHAN_DISABLED)
                 return -EINVAL;
 
+        /* Both channels should be able to initiate communication */
+        if ((ibss.channel_type == NL80211_CHAN_HT40PLUS ||
+             ibss.channel_type == NL80211_CHAN_HT40MINUS) &&
+            !cfg80211_can_beacon_sec_chan(&rdev->wiphy, ibss.channel,
+                                          ibss.channel_type))
+                return -EINVAL;
+
         ibss.channel_fixed = !!info->attrs[NL80211_ATTR_FREQ_FIXED];
         ibss.privacy = !!info->attrs[NL80211_ATTR_PRIVACY];