mac80211: support secondary channel offset in CSA

Add support for the secondary channel offset IE in channel
switch announcements. This is necessary for proper handling
of CSA on HT access points.

For this to work it is also necessary to convert everything
here to use chandef structs instead of just channels. The
driver updates aren't really correct though. In particular,
the TI wl18xx driver update can't possibly be right since
it just ignores the new channel width for lack of firmware
API.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 56 insertions, 15 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index bc6f87edc62..bd581a80e4b 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -289,6 +289,8 @@ ieee80211_determine_chantype(struct ieee80211_sub_if_data *sdata,
 	} else {
 		/* 40 MHz (and 80 MHz) must be supported for VHT */
 		ret = IEEE80211_STA_DISABLE_VHT;
+		/* also mark 40 MHz disabled */
+		ret |= IEEE80211_STA_DISABLE_40MHZ;
 		goto out;
 	}
 
@@ -964,16 +966,7 @@ static void ieee80211_chswitch_work(struct work_struct *work)
 	if (!ifmgd->associated)
 		goto out;
 
-	/*
-	 * FIXME: Here we are downgrading to NL80211_CHAN_WIDTH_20_NOHT
-	 * and don't adjust our ht/vht settings
-	 * This is wrong - we should behave according to the CSA params
-	 */
-	local->_oper_chandef.chan = local->csa_channel;
-	local->_oper_chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
-	local->_oper_chandef.center_freq1 =
-		local->_oper_chandef.chan->center_freq;
-	local->_oper_chandef.center_freq2 = 0;
+	local->_oper_chandef = local->csa_chandef;
 
 	if (!local->ops->channel_switch) {
 		/* call "hw_config" only if doing sw channel switch */
@@ -1028,13 +1021,14 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 	struct cfg80211_bss *cbss = ifmgd->associated;
 	struct ieee80211_bss *bss;
-	struct ieee80211_channel *new_ch;
 	struct ieee80211_chanctx *chanctx;
 	enum ieee80211_band new_band;
 	int new_freq;
 	u8 new_chan_no;
 	u8 count;
 	u8 mode;
+	struct cfg80211_chan_def new_chandef = {};
+	int secondary_channel_offset = -1;
 
 	ASSERT_MGD_MTX(ifmgd);
 
@@ -1048,6 +1042,19 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 	if (ifmgd->flags & IEEE80211_STA_CSA_RECEIVED)
 		return;
 
+	if (!(ifmgd->flags & IEEE80211_STA_DISABLE_HT)) {
+		/* if HT is enabled and the IE not present, it's still HT */
+		secondary_channel_offset = IEEE80211_HT_PARAM_CHA_SEC_NONE;
+		if (elems->sec_chan_offs)
+			secondary_channel_offset =
+				elems->sec_chan_offs->sec_chan_offs;
+	}
+
+	if (ifmgd->flags & IEEE80211_STA_DISABLE_40MHZ &&
+	    (secondary_channel_offset == IEEE80211_HT_PARAM_CHA_SEC_ABOVE ||
+	     secondary_channel_offset == IEEE80211_HT_PARAM_CHA_SEC_BELOW))
+		secondary_channel_offset = IEEE80211_HT_PARAM_CHA_SEC_NONE;
+
 	if (elems->ext_chansw_ie) {
 		if (!ieee80211_operating_class_to_band(
 				elems->ext_chansw_ie->new_operating_class,
@@ -1074,8 +1081,9 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 	bss = (void *)cbss->priv;
 
 	new_freq = ieee80211_channel_to_frequency(new_chan_no, new_band);
-	new_ch = ieee80211_get_channel(local->hw.wiphy, new_freq);
-	if (!new_ch || new_ch->flags & IEEE80211_CHAN_DISABLED) {
+	new_chandef.chan = ieee80211_get_channel(sdata->local->hw.wiphy, new_freq);
+	if (!new_chandef.chan ||
+	    new_chandef.chan->flags & IEEE80211_CHAN_DISABLED) {
 		sdata_info(sdata,
 			   "AP %pM switches to unsupported channel (%d MHz), disconnecting\n",
 			   ifmgd->associated->bssid, new_freq);
@@ -1084,6 +1092,39 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 		return;
 	}
 
+	switch (secondary_channel_offset) {
+	default:
+		/* secondary_channel_offset was present but is invalid */
+	case IEEE80211_HT_PARAM_CHA_SEC_NONE:
+		cfg80211_chandef_create(&new_chandef, new_chandef.chan,
+					NL80211_CHAN_HT20);
+		break;
+	case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
+		cfg80211_chandef_create(&new_chandef, new_chandef.chan,
+					NL80211_CHAN_HT40PLUS);
+		break;
+	case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
+		cfg80211_chandef_create(&new_chandef, new_chandef.chan,
+					NL80211_CHAN_HT40MINUS);
+		break;
+	case -1:
+		cfg80211_chandef_create(&new_chandef, new_chandef.chan,
+					NL80211_CHAN_NO_HT);
+		break;
+	}
+
+	if (!cfg80211_chandef_usable(local->hw.wiphy, &new_chandef,
+				     IEEE80211_CHAN_DISABLED)) {
+		sdata_info(sdata,
+			   "AP %pM switches to unsupported channel (%d MHz, width:%d, CF1/2: %d/%d MHz), disconnecting\n",
+			   ifmgd->associated->bssid, new_freq,
+			   new_chandef.width, new_chandef.center_freq1,
+			   new_chandef.center_freq2);
+		ieee80211_queue_work(&local->hw,
+				     &ifmgd->csa_connection_drop_work);
+		return;
+	}
+
 	ifmgd->flags |= IEEE80211_STA_CSA_RECEIVED;
 
 	if (local->use_chanctx) {
@@ -1111,7 +1152,7 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 	}
 	mutex_unlock(&local->chanctx_mtx);
 
-	local->csa_channel = new_ch;
+	local->csa_chandef = new_chandef;
 
 	if (mode)
 		ieee80211_stop_queues_by_reason(&local->hw,
@@ -1123,7 +1164,7 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 		struct ieee80211_channel_switch ch_switch = {
 			.timestamp = timestamp,
 			.block_tx = mode,
-			.channel = new_ch,
+			.chandef = new_chandef,
 			.count = count,
 		};