mac80211: add supported channels IE during TDLS setup

This information element is mandatory in case TDLS channel-switching is to
be supported. The channels given are ones supported and allowed to be
active in the current regulatory setting.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/tdls.c b/net/mac80211/tdls.c
index d4fe091..8fb314b 100644 (file)
--- a/net/mac80211/tdls.c
+++ b/net/mac80211/tdls.c
@@ -48,6 +48,75 @@ static void ieee80211_tdls_add_ext_capab(struct sk_buff *skb)
        *pos++ = WLAN_EXT_CAPA5_TDLS_ENABLED;
 }
 
+static u8
+ieee80211_tdls_add_subband(struct ieee80211_sub_if_data *sdata,
+                          struct sk_buff *skb, u16 start, u16 end,
+                          u16 spacing)
+{
+       u8 subband_cnt = 0, ch_cnt = 0;
+       struct ieee80211_channel *ch;
+       struct cfg80211_chan_def chandef;
+       int i, subband_start;
+
+       for (i = start; i <= end; i += spacing) {
+               if (!ch_cnt)
+                       subband_start = i;
+
+               ch = ieee80211_get_channel(sdata->local->hw.wiphy, i);
+               if (ch) {
+                       /* we will be active on the channel */
+                       u32 flags = IEEE80211_CHAN_DISABLED |
+                                   IEEE80211_CHAN_NO_IR;
+                       cfg80211_chandef_create(&chandef, ch,
+                                               NL80211_CHAN_HT20);
+                       if (cfg80211_chandef_usable(sdata->local->hw.wiphy,
+                                                   &chandef, flags)) {
+                               ch_cnt++;
+                               continue;
+                       }
+               }
+
+               if (ch_cnt) {
+                       u8 *pos = skb_put(skb, 2);
+                       *pos++ = ieee80211_frequency_to_channel(subband_start);
+                       *pos++ = ch_cnt;
+
+                       subband_cnt++;
+                       ch_cnt = 0;
+               }
+       }
+
+       return subband_cnt;
+}
+
+static void
+ieee80211_tdls_add_supp_channels(struct ieee80211_sub_if_data *sdata,
+                                struct sk_buff *skb)
+{
+       /*
+        * Add possible channels for TDLS. These are channels that are allowed
+        * to be active.
+        */
+       u8 subband_cnt;
+       u8 *pos = skb_put(skb, 2);
+
+       *pos++ = WLAN_EID_SUPPORTED_CHANNELS;
+
+       /*
+        * 5GHz and 2GHz channels numbers can overlap. Ignore this for now, as
+        * this doesn't happen in real world scenarios.
+        */
+
+       /* 2GHz, with 5MHz spacing */
+       subband_cnt = ieee80211_tdls_add_subband(sdata, skb, 2412, 2472, 5);
+
+       /* 5GHz, with 20MHz spacing */
+       subband_cnt += ieee80211_tdls_add_subband(sdata, skb, 5000, 5825, 20);
+
+       /* length */
+       *pos = 2 * subband_cnt;
+}
+
 static u16 ieee80211_get_tdls_sta_capab(struct ieee80211_sub_if_data *sdata,
                                        u16 status_code)
 {
@@ -190,6 +259,7 @@ ieee80211_tdls_add_setup_start_ies(struct ieee80211_sub_if_data *sdata,
 
        ieee80211_add_srates_ie(sdata, skb, false, band);
        ieee80211_add_ext_srates_ie(sdata, skb, false, band);
+       ieee80211_tdls_add_supp_channels(sdata, skb);
 
        /* add any custom IEs that go before Extended Capabilities */
        if (extra_ies_len) {
@@ -526,6 +596,7 @@ ieee80211_tdls_prep_mgmt_packet(struct wiphy *wiphy, struct net_device *dev,
                               26 + /* max(WMM-info, WMM-param) */
                               2 + max(sizeof(struct ieee80211_ht_cap),
                                       sizeof(struct ieee80211_ht_operation)) +
+                              50 + /* supported channels */
                               extra_ies_len +
                               sizeof(struct ieee80211_tdls_lnkie));
        if (!skb)