mac80211: split off channel switch parsing function

The channel switch parsing function can be re-used for the IBSS code,
put the common part into an extra function.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
[also move/rename chandef_downgrade]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 162 insertions, 0 deletions

diff --git a/net/mac80211/spectmgmt.c b/net/mac80211/spectmgmt.c
index 578eea3fc04d..921597e279a3 100644
--- a/net/mac80211/spectmgmt.c
+++ b/net/mac80211/spectmgmt.c
@@ -21,6 +21,168 @@
 #include "sta_info.h"
 #include "wme.h"
 
+int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
+				 struct ieee802_11_elems *elems, bool beacon,
+				 enum ieee80211_band current_band,
+				 u32 sta_flags, u8 *bssid, u8 *count, u8 *mode,
+				 struct cfg80211_chan_def *new_chandef)
+{
+	enum ieee80211_band new_band;
+	int new_freq;
+	u8 new_chan_no;
+	struct ieee80211_channel *new_chan;
+	struct cfg80211_chan_def new_vht_chandef = {};
+	const struct ieee80211_sec_chan_offs_ie *sec_chan_offs;
+	const struct ieee80211_wide_bw_chansw_ie *wide_bw_chansw_ie;
+	const struct ieee80211_ht_operation *ht_oper;
+	int secondary_channel_offset = -1;
+
+	sec_chan_offs = elems->sec_chan_offs;
+	wide_bw_chansw_ie = elems->wide_bw_chansw_ie;
+	ht_oper = elems->ht_operation;
+
+	if (sta_flags & (IEEE80211_STA_DISABLE_HT |
+			 IEEE80211_STA_DISABLE_40MHZ)) {
+		sec_chan_offs = NULL;
+		wide_bw_chansw_ie = NULL;
+		/* only used for bandwidth here */
+		ht_oper = NULL;
+	}
+
+	if (sta_flags & IEEE80211_STA_DISABLE_VHT)
+		wide_bw_chansw_ie = NULL;
+
+	if (elems->ext_chansw_ie) {
+		if (!ieee80211_operating_class_to_band(
+				elems->ext_chansw_ie->new_operating_class,
+				&new_band)) {
+			sdata_info(sdata,
+				   "cannot understand ECSA IE operating class %d, disconnecting\n",
+				   elems->ext_chansw_ie->new_operating_class);
+			return -EINVAL;
+		}
+		new_chan_no = elems->ext_chansw_ie->new_ch_num;
+		*count = elems->ext_chansw_ie->count;
+		*mode = elems->ext_chansw_ie->mode;
+	} else if (elems->ch_switch_ie) {
+		new_band = current_band;
+		new_chan_no = elems->ch_switch_ie->new_ch_num;
+		*count = elems->ch_switch_ie->count;
+		*mode = elems->ch_switch_ie->mode;
+	} else {
+		/* nothing here we understand */
+		return 1;
+	}
+
+	new_freq = ieee80211_channel_to_frequency(new_chan_no, new_band);
+	new_chan = ieee80211_get_channel(sdata->local->hw.wiphy, new_freq);
+	if (!new_chan || new_chan->flags & IEEE80211_CHAN_DISABLED) {
+		sdata_info(sdata,
+			   "BSS %pM switches to unsupported channel (%d MHz), disconnecting\n",
+			   bssid, new_freq);
+		return -EINVAL;
+	}
+
+	if (!beacon && sec_chan_offs) {
+		secondary_channel_offset = sec_chan_offs->sec_chan_offs;
+	} else if (beacon && ht_oper) {
+		secondary_channel_offset =
+			ht_oper->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET;
+	} else if (!(sta_flags & IEEE80211_STA_DISABLE_HT)) {
+		/* If it's not a beacon, HT is enabled and the IE not present,
+		 * it's 20 MHz, 802.11-2012 8.5.2.6:
+		 *	This element [the Secondary Channel Offset Element] is
+		 *	present when switching to a 40 MHz channel. It may be
+		 *	present when switching to a 20 MHz channel (in which
+		 *	case the secondary channel offset is set to SCN).
+		 */
+		secondary_channel_offset = IEEE80211_HT_PARAM_CHA_SEC_NONE;
+	}
+
+	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_chan,
+					NL80211_CHAN_HT20);
+		break;
+	case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
+		cfg80211_chandef_create(new_chandef, new_chan,
+					NL80211_CHAN_HT40PLUS);
+		break;
+	case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
+		cfg80211_chandef_create(new_chandef, new_chan,
+					NL80211_CHAN_HT40MINUS);
+		break;
+	case -1:
+		cfg80211_chandef_create(new_chandef, new_chan,
+					NL80211_CHAN_NO_HT);
+		/* keep width for 5/10 MHz channels */
+		switch (sdata->vif.bss_conf.chandef.width) {
+		case NL80211_CHAN_WIDTH_5:
+		case NL80211_CHAN_WIDTH_10:
+			new_chandef->width = sdata->vif.bss_conf.chandef.width;
+			break;
+		default:
+			break;
+		}
+		break;
+	}
+
+	if (wide_bw_chansw_ie) {
+		new_vht_chandef.chan = new_chan;
+		new_vht_chandef.center_freq1 =
+			ieee80211_channel_to_frequency(
+				wide_bw_chansw_ie->new_center_freq_seg0,
+				new_band);
+
+		switch (wide_bw_chansw_ie->new_channel_width) {
+		default:
+			/* hmmm, ignore VHT and use HT if present */
+		case IEEE80211_VHT_CHANWIDTH_USE_HT:
+			new_vht_chandef.chan = NULL;
+			break;
+		case IEEE80211_VHT_CHANWIDTH_80MHZ:
+			new_vht_chandef.width = NL80211_CHAN_WIDTH_80;
+			break;
+		case IEEE80211_VHT_CHANWIDTH_160MHZ:
+			new_vht_chandef.width = NL80211_CHAN_WIDTH_160;
+			break;
+		case IEEE80211_VHT_CHANWIDTH_80P80MHZ:
+			/* field is otherwise reserved */
+			new_vht_chandef.center_freq2 =
+				ieee80211_channel_to_frequency(
+					wide_bw_chansw_ie->new_center_freq_seg1,
+					new_band);
+			new_vht_chandef.width = NL80211_CHAN_WIDTH_80P80;
+			break;
+		}
+		if (sta_flags & IEEE80211_STA_DISABLE_80P80MHZ &&
+		    new_vht_chandef.width == NL80211_CHAN_WIDTH_80P80)
+			ieee80211_chandef_downgrade(&new_vht_chandef);
+		if (sta_flags & IEEE80211_STA_DISABLE_160MHZ &&
+		    new_vht_chandef.width == NL80211_CHAN_WIDTH_160)
+			ieee80211_chandef_downgrade(&new_vht_chandef);
+		if (sta_flags & IEEE80211_STA_DISABLE_40MHZ &&
+		    new_vht_chandef.width > NL80211_CHAN_WIDTH_20)
+			ieee80211_chandef_downgrade(&new_vht_chandef);
+	}
+
+	/* if VHT data is there validate & use it */
+	if (new_vht_chandef.chan) {
+		if (!cfg80211_chandef_compatible(&new_vht_chandef,
+						 new_chandef)) {
+			sdata_info(sdata,
+				   "BSS %pM: CSA has inconsistent channel data, disconnecting\n",
+				   bssid);
+			return -EINVAL;
+		}
+		*new_chandef = new_vht_chandef;
+	}
+
+	return 0;
+}
+
 static void ieee80211_send_refuse_measurement_request(struct ieee80211_sub_if_data *sdata,
 					struct ieee80211_msrment_ie *request_ie,
 					const u8 *da, const u8 *bssid,