nl80211/cfg80211: support VHT channel configuration

Change nl80211 to support specifying a VHT (or HT)
using the control channel frequency (as before) and
new attributes for the channel width and first and
second center frequency. The old channel type is of
course still supported for HT.

Also change the cfg80211 channel definition struct
to support these by adding the relevant fields to
it (and removing the _type field.)

This also adds new helper functions:
 - cfg80211_chandef_create to create a channel def
   struct given the control channel and channel type,
 - cfg80211_chandef_identical to check if two channel
   definitions are identical
 - cfg80211_chandef_compatible to check if the given
   channel definitions are compatible, and return the
   wider of the two

This isn't entirely complete, but that doesn't matter
until we have a driver using it. In particular, it's
missing
 - regulatory checks on the usable bandwidth (if that
   even makes sense)
 - regulatory TX power (database can't deal with it)
 - a proper channel compatibility calculation for the
   new channel types

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

1 files changed, 110 insertions, 50 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 999108c..15158a3 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -223,8 +223,13 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
 	[NL80211_ATTR_WIPHY_NAME] = { .type = NLA_NUL_STRING,
 				      .len = 20-1 },
 	[NL80211_ATTR_WIPHY_TXQ_PARAMS] = { .type = NLA_NESTED },
+
 	[NL80211_ATTR_WIPHY_FREQ] = { .type = NLA_U32 },
 	[NL80211_ATTR_WIPHY_CHANNEL_TYPE] = { .type = NLA_U32 },
+	[NL80211_ATTR_CHANNEL_WIDTH] = { .type = NLA_U32 },
+	[NL80211_ATTR_CENTER_FREQ1] = { .type = NLA_U32 },
+	[NL80211_ATTR_CENTER_FREQ2] = { .type = NLA_U32 },
+
 	[NL80211_ATTR_WIPHY_RETRY_SHORT] = { .type = NLA_U8 },
 	[NL80211_ATTR_WIPHY_RETRY_LONG] = { .type = NLA_U8 },
 	[NL80211_ATTR_WIPHY_FRAG_THRESHOLD] = { .type = NLA_U32 },
@@ -1360,35 +1365,13 @@ static bool nl80211_can_set_dev_channel(struct wireless_dev *wdev)
 		wdev->iftype == NL80211_IFTYPE_P2P_GO;
 }
 
-static bool nl80211_valid_channel_type(struct genl_info *info,
-				       enum nl80211_channel_type *channel_type)
-{
-	enum nl80211_channel_type tmp;
-
-	if (!info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE])
-		return false;
-
-	tmp = nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE]);
-	if (tmp != NL80211_CHAN_NO_HT &&
-	    tmp != NL80211_CHAN_HT20 &&
-	    tmp != NL80211_CHAN_HT40PLUS &&
-	    tmp != NL80211_CHAN_HT40MINUS)
-		return false;
-
-	if (channel_type)
-		*channel_type = tmp;
-
-	return true;
-}
-
 static int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
 				 struct genl_info *info,
 				 struct cfg80211_chan_def *chandef)
 {
 	struct ieee80211_sta_ht_cap *ht_cap;
-	struct ieee80211_channel *sc;
-	u32 control_freq;
-	int offs;
+	struct ieee80211_sta_vht_cap *vht_cap;
+	u32 control_freq, width;
 
 	if (!info->attrs[NL80211_ATTR_WIPHY_FREQ])
 		return -EINVAL;
@@ -1396,47 +1379,105 @@ static int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
 	control_freq = nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]);
 
 	chandef->chan = ieee80211_get_channel(&rdev->wiphy, control_freq);
-	chandef->_type = NL80211_CHAN_NO_HT;
-
-	if (info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE] &&
-	    !nl80211_valid_channel_type(info, &chandef->_type))
-		return -EINVAL;
+	chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
+	chandef->center_freq1 = control_freq;
+	chandef->center_freq2 = 0;
 
 	/* Primary channel not allowed */
 	if (!chandef->chan || chandef->chan->flags & IEEE80211_CHAN_DISABLED)
 		return -EINVAL;
 
+	if (info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE]) {
+		enum nl80211_channel_type chantype;
+
+		chantype = nla_get_u32(
+				info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE]);
+
+		switch (chantype) {
+		case NL80211_CHAN_NO_HT:
+		case NL80211_CHAN_HT20:
+		case NL80211_CHAN_HT40PLUS:
+		case NL80211_CHAN_HT40MINUS:
+			cfg80211_chandef_create(chandef, chandef->chan,
+						chantype);
+			break;
+		default:
+			return -EINVAL;
+		}
+	} else if (info->attrs[NL80211_ATTR_CHANNEL_WIDTH]) {
+		chandef->width =
+			nla_get_u32(info->attrs[NL80211_ATTR_CHANNEL_WIDTH]);
+		if (info->attrs[NL80211_ATTR_CENTER_FREQ1])
+			chandef->center_freq1 =
+				nla_get_u32(
+					info->attrs[NL80211_ATTR_CENTER_FREQ1]);
+		if (info->attrs[NL80211_ATTR_CENTER_FREQ2])
+			chandef->center_freq2 =
+				nla_get_u32(
+					info->attrs[NL80211_ATTR_CENTER_FREQ2]);
+	}
+
 	ht_cap = &rdev->wiphy.bands[chandef->chan->band]->ht_cap;
+	vht_cap = &rdev->wiphy.bands[chandef->chan->band]->vht_cap;
 
-	switch (chandef->_type) {
-	case NL80211_CHAN_NO_HT:
+	if (!cfg80211_chan_def_valid(chandef))
+		return -EINVAL;
+
+	switch (chandef->width) {
+	case NL80211_CHAN_WIDTH_20:
+		if (!ht_cap->ht_supported)
+			return -EINVAL;
+	case NL80211_CHAN_WIDTH_20_NOHT:
+		width = 20;
 		break;
-	case NL80211_CHAN_HT40MINUS:
-		if (chandef->chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
+	case NL80211_CHAN_WIDTH_40:
+		width = 40;
+		/* quick early regulatory check */
+		if (chandef->center_freq1 < control_freq &&
+		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
+			return -EINVAL;
+		if (chandef->center_freq1 > control_freq &&
+		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
+			return -EINVAL;
+		if (!ht_cap->ht_supported)
 			return -EINVAL;
-		offs = -20;
-		/* fall through */
-	case NL80211_CHAN_HT40PLUS:
-		if (chandef->_type == NL80211_CHAN_HT40PLUS) {
-			if (chandef->chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
-				return -EINVAL;
-			offs = 20;
-		}
 		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
 		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
 			return -EINVAL;
-
-		sc = ieee80211_get_channel(&rdev->wiphy,
-					   chandef->chan->center_freq + offs);
-		if (!sc || sc->flags & IEEE80211_CHAN_DISABLED)
+		break;
+	case NL80211_CHAN_WIDTH_80:
+		width = 80;
+		if (!vht_cap->vht_supported)
 			return -EINVAL;
-		/* fall through */
-	case NL80211_CHAN_HT20:
-		if (!ht_cap->ht_supported)
+		break;
+	case NL80211_CHAN_WIDTH_80P80:
+		width = 80;
+		if (!vht_cap->vht_supported)
+			return -EINVAL;
+		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ))
+			return -EINVAL;
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		width = 160;
+		if (!vht_cap->vht_supported)
+			return -EINVAL;
+		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ))
 			return -EINVAL;
 		break;
+	default:
+		return -EINVAL;
 	}
 
+	if (!cfg80211_secondary_chans_ok(&rdev->wiphy, chandef->center_freq1,
+					 width, IEEE80211_CHAN_DISABLED))
+		return -EINVAL;
+	if (chandef->center_freq2 &&
+	    !cfg80211_secondary_chans_ok(&rdev->wiphy, chandef->center_freq2,
+					 width, IEEE80211_CHAN_DISABLED))
+		return -EINVAL;
+
+	/* TODO: missing regulatory check on bandwidth */
+
 	return 0;
 }
 
@@ -1800,10 +1841,28 @@ static inline u64 wdev_id(struct wireless_dev *wdev)
 static int nl80211_send_chandef(struct sk_buff *msg,
 				 struct cfg80211_chan_def *chandef)
 {
+	WARN_ON(!cfg80211_chan_def_valid(chandef));
+
 	if (nla_put_u32(msg, NL80211_ATTR_WIPHY_FREQ,
 			chandef->chan->center_freq))
 		return -ENOBUFS;
-	if (nla_put_u32(msg, NL80211_ATTR_WIPHY_CHANNEL_TYPE, chandef->_type))
+	switch (chandef->width) {
+	case NL80211_CHAN_WIDTH_20_NOHT:
+	case NL80211_CHAN_WIDTH_20:
+	case NL80211_CHAN_WIDTH_40:
+		if (nla_put_u32(msg, NL80211_ATTR_WIPHY_CHANNEL_TYPE,
+				cfg80211_get_chandef_type(chandef)))
+			return -ENOBUFS;
+		break;
+	default:
+		break;
+	}
+	if (nla_put_u32(msg, NL80211_ATTR_CHANNEL_WIDTH, chandef->width))
+		return -ENOBUFS;
+	if (nla_put_u32(msg, NL80211_ATTR_CENTER_FREQ1, chandef->center_freq1))
+		return -ENOBUFS;
+	if (chandef->center_freq2 &&
+	    nla_put_u32(msg, NL80211_ATTR_CENTER_FREQ2, chandef->center_freq2))
 		return -ENOBUFS;
 	return 0;
 }
@@ -5447,7 +5506,8 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
 		if (IS_ERR(connkeys))
 			return PTR_ERR(connkeys);
 
-		if ((ibss.chandef._type != NL80211_CHAN_NO_HT) && no_ht) {
+		if ((ibss.chandef.width != NL80211_CHAN_WIDTH_20_NOHT) &&
+		    no_ht) {
 			kfree(connkeys);
 			return -EINVAL;
 		}