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From: Michael-CY Lee <michael-cy.lee@mediatek.com>
To: linux-wireless <linux-wireless@vger.kernel.org>
CC: Johannes Berg <johannes@sipsolutions.net>, Felix Fietkau <nbd@nbd.name>,
	Lorenzo Bianconi <lorenzo@kernel.org>, Evelyn Tsai
	<evelyn.tsai@mediatek.com>, Money Wang <money.wang@mediatek.com>,
	linux-mediatek <linux-mediatek@lists.infradead.org>, Michael-CY Lee
	<michael-cy.lee@mediatek.com>
Subject: [PATCH v3,2/2] wifi: mac80211: refactor STA CSA parsing flows
Date: Wed, 29 Nov 2023 13:43:21 +0800
Message-ID: <20231129054321.10199-2-michael-cy.lee@mediatek.com>
In-Reply-To: <20231129054321.10199-1-michael-cy.lee@mediatek.com>
References: <20231129054321.10199-1-michael-cy.lee@mediatek.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain

The new Wi-Fi Standard (IEEE P80211be D4.1) specifies that the Wide
Bandwidth Channel Switch (WBCS) Element subfields have the same
definitions as VHT operation information if the operating band is not
S1G.

The problem comes when the BSS is in 6 GHz band, the STA parses the WBCS
Element by ieee80211_chandef_vht_oper(), which checks the capabilities for
HT/VHT mode, not HE/EHT mode.

This patch refactors STA CSA parsing flow so that the corresponding
capabilities can be checked. Also, it adds the way to use op_class in ECSA
Element to build a new chandef.

In summary, the new steps for STA to handle CSA event are:
1. build the new chandef from the CSA-related Elements.
   (CSA, ECSA, WBCS, etc.)
2. convert the new chandef into operation information according to the
   operating band in order to check if the new chandef fits STA's
   capabilities.
3. downgrade the bandwidth until current bandwidth is not disabled.

Signed-off-by: Michael-CY Lee <michael-cy.lee@mediatek.com>
Signed-off-by: Money Wang <money.wang@mediatek.com>
---
v3:
  Version 2 follows draft 3.2, while version 3 follows draft 4.1.
  Also, version 3 simplifies the CSA handling steps.
---
 net/mac80211/spectmgmt.c | 349 +++++++++++++++++++++++++++++++++------
 1 file changed, 294 insertions(+), 55 deletions(-)

diff --git a/net/mac80211/spectmgmt.c b/net/mac80211/spectmgmt.c
index 55959b0b24c5..9a5f743ee750 100644
--- a/net/mac80211/spectmgmt.c
+++ b/net/mac80211/spectmgmt.c
@@ -19,6 +19,236 @@
 #include "sta_info.h"
 #include "wme.h"
 
+static inline void
+wbcs_ie_to_chandef(const struct ieee80211_wide_bw_chansw_ie *wbcs_ie,
+		   struct cfg80211_chan_def *chandef)
+{
+	u8 ccfs0 = wbcs_ie->new_center_freq_seg0;
+	u8 ccfs1 = wbcs_ie->new_center_freq_seg1;
+	u32 cf0 = ieee80211_channel_to_frequency(ccfs0, chandef->chan->band);
+	u32 cf1 = ieee80211_channel_to_frequency(ccfs1, chandef->chan->band);
+
+	switch (wbcs_ie->new_channel_width) {
+	case IEEE80211_VHT_CHANWIDTH_160MHZ:
+		chandef->width = NL80211_CHAN_WIDTH_160;
+		chandef->center_freq1 = cf0;
+		break;
+	case IEEE80211_VHT_CHANWIDTH_80P80MHZ:
+		chandef->width = NL80211_CHAN_WIDTH_80P80;
+		chandef->center_freq1 = cf0;
+		chandef->center_freq2 = cf1;
+		break;
+	case IEEE80211_VHT_CHANWIDTH_80MHZ:
+		chandef->width = NL80211_CHAN_WIDTH_80;
+		chandef->center_freq1 = cf0;
+
+		if (ccfs1) {
+			u8 diff = abs(ccfs0 - ccfs1);
+
+			if (diff == 8) {
+				chandef->width = NL80211_CHAN_WIDTH_160;
+				chandef->center_freq1 = cf1;
+			} else if (diff > 8) {
+				chandef->width = NL80211_CHAN_WIDTH_80P80;
+				chandef->center_freq2 = cf1;
+			}
+		}
+		break;
+	case IEEE80211_VHT_CHANWIDTH_USE_HT:
+	default:
+		/* If the WBCS Element is present, new channel bandwidth is
+		 * at least 40 MHz.
+		 */
+		chandef->width = NL80211_CHAN_WIDTH_40;
+		chandef->center_freq1 = cf0;
+		break;
+	}
+}
+
+static inline int
+validate_chandef_by_ht_vht_oper(struct ieee80211_sub_if_data *sdata,
+				ieee80211_conn_flags_t conn_flags,
+				u32 vht_cap_info,
+				struct cfg80211_chan_def *chandef)
+{
+	u32 control_freq, center_freq1, center_freq2;
+	enum nl80211_chan_width chan_width;
+	struct ieee80211_ht_operation *ht_oper = NULL;
+	struct ieee80211_vht_operation *vht_oper = NULL;
+
+	if (conn_flags & (IEEE80211_CONN_DISABLE_HT |
+			  IEEE80211_CONN_DISABLE_40MHZ)) {
+		chandef->chan = NULL;
+		return 0;
+	}
+
+	control_freq = chandef->chan->center_freq;
+	center_freq1 = chandef->center_freq1;
+	center_freq2 = chandef->center_freq2;
+	chan_width = chandef->width;
+
+	ht_oper = kzalloc(sizeof(*ht_oper), GFP_KERNEL);
+	if (!ht_oper)
+		return -ENOMEM;
+
+	ht_oper->primary_chan = ieee80211_frequency_to_channel(control_freq);
+	if (control_freq != center_freq1)
+		ht_oper->ht_param = control_freq > center_freq1 ?
+			IEEE80211_HT_PARAM_CHA_SEC_BELOW :
+			IEEE80211_HT_PARAM_CHA_SEC_ABOVE;
+	else
+		ht_oper->ht_param = IEEE80211_HT_PARAM_CHA_SEC_NONE;
+
+	ieee80211_chandef_ht_oper(ht_oper, chandef);
+
+	if (conn_flags & IEEE80211_CONN_DISABLE_VHT) {
+		kfree(ht_oper);
+		return 0;
+	}
+
+	vht_oper = kzalloc(sizeof(*vht_oper), GFP_KERNEL);
+	if (!vht_oper) {
+		kfree(ht_oper);
+		return -ENOMEM;
+	}
+
+	vht_oper->center_freq_seg0_idx =
+		ieee80211_frequency_to_channel(center_freq1);
+	vht_oper->center_freq_seg1_idx = center_freq2 ?
+		ieee80211_frequency_to_channel(center_freq2) : 0;
+
+	switch (chan_width) {
+	case NL80211_CHAN_WIDTH_320:
+		WARN_ON(1);
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		vht_oper->chan_width = IEEE80211_VHT_CHANWIDTH_80MHZ;
+		vht_oper->center_freq_seg1_idx = vht_oper->center_freq_seg0_idx;
+		vht_oper->center_freq_seg0_idx +=
+			control_freq < center_freq1 ? -8 : 8;
+		break;
+	case NL80211_CHAN_WIDTH_80P80:
+		vht_oper->chan_width = IEEE80211_VHT_CHANWIDTH_80MHZ;
+		break;
+	case NL80211_CHAN_WIDTH_80:
+		vht_oper->chan_width = IEEE80211_VHT_CHANWIDTH_80MHZ;
+		break;
+	default:
+		vht_oper->chan_width = IEEE80211_VHT_CHANWIDTH_USE_HT;
+		break;
+	}
+
+	ht_oper->operation_mode =
+		cpu_to_le16(vht_oper->center_freq_seg1_idx <<
+				IEEE80211_HT_OP_MODE_CCFS2_SHIFT);
+
+	if (!ieee80211_chandef_vht_oper(&sdata->local->hw, vht_cap_info,
+					vht_oper, ht_oper, chandef))
+		chandef->chan = NULL;
+
+	kfree(ht_oper);
+	kfree(vht_oper);
+
+	return 0;
+}
+
+static inline int
+validate_chandef_by_6ghz_he_eht_oper(struct ieee80211_sub_if_data *sdata,
+				     ieee80211_conn_flags_t conn_flags,
+				     struct cfg80211_chan_def *chandef)
+{
+	u32 size, control_freq, center_freq1, center_freq2;
+	enum nl80211_chan_width chan_width;
+	struct ieee80211_he_operation *he_oper = NULL;
+	struct ieee80211_he_6ghz_oper *he_6ghz_oper;
+	struct ieee80211_eht_operation *eht_oper = NULL;
+	struct ieee80211_eht_operation_info *eht_oper_info;
+
+	if (conn_flags & (IEEE80211_CONN_DISABLE_HE)) {
+		chandef->chan = NULL;
+		return 0;
+	}
+
+	control_freq = chandef->chan->center_freq;
+	center_freq1 = chandef->center_freq1;
+	center_freq2 = chandef->center_freq2;
+	chan_width = chandef->width;
+
+	size = sizeof(struct ieee80211_he_operation) +
+	       sizeof(struct ieee80211_he_6ghz_oper);
+
+	he_oper = kzalloc(size, GFP_KERNEL);
+	if (!he_oper)
+		return -ENOMEM;
+
+	if (!(conn_flags & IEEE80211_CONN_DISABLE_EHT)) {
+		size = sizeof(struct ieee80211_eht_operation) +
+		       sizeof(struct ieee80211_eht_operation_info);
+
+		eht_oper = kzalloc(size, GFP_KERNEL);
+		if (!eht_oper) {
+			kfree(he_oper);
+			return -ENOMEM;
+		}
+	}
+
+	he_oper->he_oper_params = cpu_to_le32(u32_encode_bits(1,
+					IEEE80211_HE_OPERATION_6GHZ_OP_INFO));
+
+	he_6ghz_oper = (struct ieee80211_he_6ghz_oper *)he_oper->optional;
+	he_6ghz_oper->primary =
+		ieee80211_frequency_to_channel(control_freq);
+	he_6ghz_oper->ccfs0 = ieee80211_frequency_to_channel(center_freq1);
+	he_6ghz_oper->ccfs1 = center_freq2 ?
+		ieee80211_frequency_to_channel(center_freq2) : 0;
+
+	switch (chan_width) {
+	case NL80211_CHAN_WIDTH_320:
+		he_6ghz_oper->ccfs1 = he_6ghz_oper->ccfs0;
+		he_6ghz_oper->ccfs0 += control_freq < center_freq1 ? -16 : 16;
+		he_6ghz_oper->control = IEEE80211_EHT_OPER_CHAN_WIDTH_320MHZ;
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		he_6ghz_oper->ccfs1 = he_6ghz_oper->ccfs0;
+		he_6ghz_oper->ccfs0 += control_freq < center_freq1 ? -8 : 8;
+		fallthrough;
+	case NL80211_CHAN_WIDTH_80P80:
+		he_6ghz_oper->control =
+			IEEE80211_HE_6GHZ_OPER_CTRL_CHANWIDTH_160MHZ;
+		break;
+	case NL80211_CHAN_WIDTH_80:
+		he_6ghz_oper->control =
+			IEEE80211_HE_6GHZ_OPER_CTRL_CHANWIDTH_80MHZ;
+		break;
+	case NL80211_CHAN_WIDTH_40:
+		he_6ghz_oper->control =
+			IEEE80211_HE_6GHZ_OPER_CTRL_CHANWIDTH_40MHZ;
+		break;
+	default:
+		he_6ghz_oper->control =
+			IEEE80211_HE_6GHZ_OPER_CTRL_CHANWIDTH_20MHZ;
+		break;
+	}
+
+	if (eht_oper) {
+		eht_oper->params = IEEE80211_EHT_OPER_INFO_PRESENT;
+
+		eht_oper_info =
+			(struct ieee80211_eht_operation_info *)eht_oper->optional;
+		eht_oper_info->control = he_6ghz_oper->control;
+		eht_oper_info->ccfs0 = he_6ghz_oper->ccfs0;
+		eht_oper_info->ccfs1 = he_6ghz_oper->ccfs1;
+	}
+
+	if (!ieee80211_chandef_he_6ghz_oper(sdata, he_oper, eht_oper, chandef))
+		chandef->chan = NULL;
+
+	kfree(he_oper);
+	kfree(eht_oper);
+
+	return 0;
+}
+
 int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
 				 struct ieee802_11_elems *elems,
 				 enum nl80211_band current_band,
@@ -27,13 +257,14 @@ int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
 				 struct ieee80211_csa_ie *csa_ie)
 {
 	enum nl80211_band new_band = current_band;
-	int new_freq;
-	u8 new_chan_no;
+	int new_freq, ret;
+	u8 new_chan_no = 0, new_op_class = 0;
 	struct ieee80211_channel *new_chan;
-	struct cfg80211_chan_def new_vht_chandef = {};
+	struct cfg80211_chan_def new_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_bandwidth_indication *bwi;
+	const struct ieee80211_ext_chansw_ie *ext_chansw_ie;
 	int secondary_channel_offset = -1;
 
 	memset(csa_ie, 0, sizeof(*csa_ie));
@@ -41,6 +272,7 @@ int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
 	sec_chan_offs = elems->sec_chan_offs;
 	wide_bw_chansw_ie = elems->wide_bw_chansw_ie;
 	bwi = elems->bandwidth_indication;
+	ext_chansw_ie = elems->ext_chansw_ie;
 
 	if (conn_flags & (IEEE80211_CONN_DISABLE_HT |
 			  IEEE80211_CONN_DISABLE_40MHZ)) {
@@ -51,26 +283,30 @@ int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
 	if (conn_flags & IEEE80211_CONN_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, ignoring\n",
-				   elems->ext_chansw_ie->new_operating_class);
+	if (ext_chansw_ie) {
+		new_op_class = ext_chansw_ie->new_operating_class;
+		if (!ieee80211_operating_class_to_band(new_op_class, &new_band)) {
+			new_op_class = 0;
+			sdata_info(sdata, "cannot understand ECSA IE "
+					  "operating class, %d, ignoring\n",
+				   ext_chansw_ie->new_operating_class);
+		} else {
+			new_chan_no = ext_chansw_ie->new_ch_num;
+			csa_ie->count = ext_chansw_ie->count;
+			csa_ie->mode = ext_chansw_ie->mode;
 		}
-		new_chan_no = elems->ext_chansw_ie->new_ch_num;
-		csa_ie->count = elems->ext_chansw_ie->count;
-		csa_ie->mode = elems->ext_chansw_ie->mode;
-	} else if (elems->ch_switch_ie) {
+	}
+
+	if (!new_op_class && elems->ch_switch_ie) {
 		new_chan_no = elems->ch_switch_ie->new_ch_num;
 		csa_ie->count = elems->ch_switch_ie->count;
 		csa_ie->mode = elems->ch_switch_ie->mode;
-	} else {
-		/* nothing here we understand */
-		return 1;
 	}
 
+	/* nothing here we understand */
+	if (!new_chan_no)
+		return 1;
+
 	/* Mesh Channel Switch Parameters Element */
 	if (elems->mesh_chansw_params_ie) {
 		csa_ie->ttl = elems->mesh_chansw_params_ie->mesh_ttl;
@@ -134,65 +370,68 @@ int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
 		break;
 	}
 
+	/* parse one of the Elements to build a new chandef */
+	memset(&new_chandef, 0, sizeof(new_chandef));
+	new_chandef.chan = new_chan;
 	if (bwi) {
 		/* start with the CSA one */
-		new_vht_chandef = csa_ie->chandef;
+		new_chandef = csa_ie->chandef;
 		/* and update the width accordingly */
 		/* FIXME: support 160/320 */
 		ieee80211_chandef_eht_oper(&bwi->info, true, true,
-					   &new_vht_chandef);
-	} else if (wide_bw_chansw_ie) {
-		u8 new_seg1 = wide_bw_chansw_ie->new_center_freq_seg1;
-		struct ieee80211_vht_operation vht_oper = {
-			.chan_width =
-				wide_bw_chansw_ie->new_channel_width,
-			.center_freq_seg0_idx =
-				wide_bw_chansw_ie->new_center_freq_seg0,
-			.center_freq_seg1_idx = new_seg1,
-			/* .basic_mcs_set doesn't matter */
-		};
-		struct ieee80211_ht_operation ht_oper = {
-			.operation_mode =
-				cpu_to_le16(new_seg1 <<
-					    IEEE80211_HT_OP_MODE_CCFS2_SHIFT),
-		};
-
-		/* default, for the case of IEEE80211_VHT_CHANWIDTH_USE_HT,
-		 * to the previously parsed chandef
-		 */
-		new_vht_chandef = csa_ie->chandef;
+					   &new_chandef);
+	} else if (!ieee80211_operating_class_to_chandef(new_op_class, new_chan,
+							 &new_chandef)) {
+		if (wide_bw_chansw_ie)
+			wbcs_ie_to_chandef(wide_bw_chansw_ie, &new_chandef);
+		else
+			new_chandef = csa_ie->chandef;
+	}
+
+	if (!cfg80211_chandef_valid(&new_chandef))
+		new_chandef = csa_ie->chandef;
 
-		/* ignore if parsing fails */
-		if (!ieee80211_chandef_vht_oper(&sdata->local->hw,
-						vht_cap_info,
-						&vht_oper, &ht_oper,
-						&new_vht_chandef))
-			new_vht_chandef.chan = NULL;
+	/* check if the new chandef fits the capabilities */
+	if (new_band == NL80211_BAND_6GHZ) {
+		ret = validate_chandef_by_6ghz_he_eht_oper(sdata, conn_flags,
+							   &new_chandef);
+		if (ret)
+			return ret;
+	} else {
+		ret = validate_chandef_by_ht_vht_oper(sdata, conn_flags,
+						      vht_cap_info, &new_chandef);
+		if (ret)
+			return ret;
+	}
+
+	/* if data is there validate the bandwidth & use it */
+	if (new_chandef.chan) {
+		if (conn_flags & IEEE80211_CONN_DISABLE_320MHZ &&
+		    new_chandef.width == NL80211_CHAN_WIDTH_320)
+			ieee80211_chandef_downgrade(&new_chandef);
 
 		if (conn_flags & IEEE80211_CONN_DISABLE_80P80MHZ &&
-		    new_vht_chandef.width == NL80211_CHAN_WIDTH_80P80)
-			ieee80211_chandef_downgrade(&new_vht_chandef);
+		    new_chandef.width == NL80211_CHAN_WIDTH_80P80)
+			ieee80211_chandef_downgrade(&new_chandef);
+
 		if (conn_flags & IEEE80211_CONN_DISABLE_160MHZ &&
-		    new_vht_chandef.width == NL80211_CHAN_WIDTH_160)
-			ieee80211_chandef_downgrade(&new_vht_chandef);
-	}
+		    new_chandef.width == NL80211_CHAN_WIDTH_160)
+			ieee80211_chandef_downgrade(&new_chandef);
 
-	/* if VHT data is there validate & use it */
-	if (new_vht_chandef.chan) {
-		if (!cfg80211_chandef_compatible(&new_vht_chandef,
+		if (!cfg80211_chandef_compatible(&new_chandef,
 						 &csa_ie->chandef)) {
 			sdata_info(sdata,
 				   "BSS %pM: CSA has inconsistent channel data, disconnecting\n",
 				   bssid);
 			return -EINVAL;
 		}
-		csa_ie->chandef = new_vht_chandef;
+		csa_ie->chandef = new_chandef;
 	}
 
 	if (elems->max_channel_switch_time)
 		csa_ie->max_switch_time =
 			(elems->max_channel_switch_time[0] << 0) |
-			(elems->max_channel_switch_time[1] <<  8) |
+			(elems->max_channel_switch_time[1] << 8) |
 			(elems->max_channel_switch_time[2] << 16);
 
 	return 0;
-- 
2.25.1