From:   Johannes Berg <johannes@sipsolutions.net>
To:     linux-wireless@vger.kernel.org
Cc:     Aloka Dixit <quic_alokad@quicinc.com>,
        Muna Sinada <quic_msinada@quicinc.com>,
        Johannes Berg <johannes.berg@intel.com>,
        Miri Korenblit <miriam.rachel.korenblit@intel.com>
Subject: [PATCH] wifi: mac80211: mlme: handle EHT channel puncturing
Date:   Fri, 27 Jan 2023 12:39:31 +0100
Message-Id: <20230127123930.4fbc74582331.I3547481d49f958389f59dfeba3fcc75e72b0aa6e@changeid>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Johannes Berg <johannes.berg@intel.com>

Handle the Puncturing info received from the AP in the
EHT Operation element in beacons.

If the info is invalid:
 - during association: disable EHT connection for the AP
 - after association: disconnect

This commit includes many (internal) bugfixes and spec
updates various people.

Co-developed-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/net/mac80211.h     |   5 +-
 net/mac80211/cfg.c         |   2 +-
 net/mac80211/chan.c        |   2 +-
 net/mac80211/ieee80211_i.h |   2 +-
 net/mac80211/mlme.c        | 224 ++++++++++++++++++++++++++++++++++++-
 5 files changed, 228 insertions(+), 7 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 2635e6de8101..54ffc0cc2918 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -340,7 +340,7 @@ struct ieee80211_vif_chanctx_switch {
  * @BSS_CHANGED_FILS_DISCOVERY: FILS discovery status changed.
  * @BSS_CHANGED_UNSOL_BCAST_PROBE_RESP: Unsolicited broadcast probe response
  *	status changed.
- *
+ * @BSS_CHANGED_EHT_PUNCTURING: The channel puncturing bitmap changed.
  */
 enum ieee80211_bss_change {
 	BSS_CHANGED_ASSOC		= 1<<0,
@@ -375,6 +375,7 @@ enum ieee80211_bss_change {
 	BSS_CHANGED_HE_BSS_COLOR	= 1<<29,
 	BSS_CHANGED_FILS_DISCOVERY      = 1<<30,
 	BSS_CHANGED_UNSOL_BCAST_PROBE_RESP = 1<<31,
+	BSS_CHANGED_EHT_PUNCTURING	= BIT_ULL(32),
 
 	/* when adding here, make sure to change ieee80211_reconfig */
 };
@@ -640,6 +641,7 @@ struct ieee80211_fils_discovery {
  * @tx_pwr_env_num: number of @tx_pwr_env.
  * @pwr_reduction: power constraint of BSS.
  * @eht_support: does this BSS support EHT
+ * @eht_puncturing: bitmap to indicate which channels are punctured in this BSS
  * @csa_active: marks whether a channel switch is going on. Internally it is
  *	write-protected by sdata_lock and local->mtx so holding either is fine
  *	for read access.
@@ -736,6 +738,7 @@ struct ieee80211_bss_conf {
 	u8 tx_pwr_env_num;
 	u8 pwr_reduction;
 	bool eht_support;
+	u16 eht_puncturing;
 
 	bool csa_active;
 	bool mu_mimo_owner;
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index f5d43f42f6d8..24b8648cfafa 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -4171,7 +4171,7 @@ static int ieee80211_set_ap_chanwidth(struct wiphy *wiphy,
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_link_data *link;
 	int ret;
-	u32 changed = 0;
+	u64 changed = 0;
 
 	link = sdata_dereference(sdata->link[link_id], sdata);
 
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index e72cf0749d49..dbc34fbe7c8f 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -1916,7 +1916,7 @@ int ieee80211_link_use_reserved_context(struct ieee80211_link_data *link)
 
 int ieee80211_link_change_bandwidth(struct ieee80211_link_data *link,
 				    const struct cfg80211_chan_def *chandef,
-				    u32 *changed)
+				    u64 *changed)
 {
 	struct ieee80211_sub_if_data *sdata = link->sdata;
 	struct ieee80211_bss_conf *link_conf = link->conf;
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index d16606e84e22..e833d472ff72 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -2478,7 +2478,7 @@ int ieee80211_link_unreserve_chanctx(struct ieee80211_link_data *link);
 int __must_check
 ieee80211_link_change_bandwidth(struct ieee80211_link_data *link,
 				const struct cfg80211_chan_def *chandef,
-				u32 *changed);
+				u64 *changed);
 void ieee80211_link_release_channel(struct ieee80211_link_data *link);
 void ieee80211_link_vlan_copy_chanctx(struct ieee80211_link_data *link);
 void ieee80211_link_copy_chanctx_to_vlans(struct ieee80211_link_data *link,
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 0aee2392dd29..a14a5ea2bffd 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -8,7 +8,7 @@
  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
  * Copyright 2013-2014  Intel Mobile Communications GmbH
  * Copyright (C) 2015 - 2017 Intel Deutschland GmbH
- * Copyright (C) 2018 - 2022 Intel Corporation
+ * Copyright (C) 2018 - 2023 Intel Corporation
  */
 
 #include <linux/delay.h>
@@ -88,6 +88,141 @@ MODULE_PARM_DESC(probe_wait_ms,
  */
 #define IEEE80211_SIGNAL_AVE_MIN_COUNT	4
 
+struct ieee80211_per_bw_puncturing_values {
+	u8 len;
+	const u16 *valid_values;
+};
+
+static const u16 puncturing_values_80mhz[] = {
+	0x8, 0x4, 0x2, 0x1
+};
+
+static const u16 puncturing_values_160mhz[] = {
+	 0x80, 0x40, 0x20, 0x10, 0x8, 0x4, 0x2, 0x1, 0xc0, 0x30, 0xc, 0x3
+};
+
+static const u16 puncturing_values_320mhz[] = {
+	0xc000, 0x3000, 0xc00, 0x300, 0xc0, 0x30, 0xc, 0x3, 0xf000, 0xf00,
+	0xf0, 0xf, 0xfc00, 0xf300, 0xf0c0, 0xf030, 0xf00c, 0xf003, 0xc00f,
+	0x300f, 0xc0f, 0x30f, 0xcf, 0x3f
+};
+
+#define IEEE80211_PER_BW_VALID_PUNCTURING_VALUES(_bw) \
+	{ \
+		.len = ARRAY_SIZE(puncturing_values_ ## _bw ## mhz), \
+		.valid_values = puncturing_values_ ## _bw ## mhz \
+	}
+
+static const struct ieee80211_per_bw_puncturing_values per_bw_puncturing[] = {
+	IEEE80211_PER_BW_VALID_PUNCTURING_VALUES(80),
+	IEEE80211_PER_BW_VALID_PUNCTURING_VALUES(160),
+	IEEE80211_PER_BW_VALID_PUNCTURING_VALUES(320)
+};
+
+static bool ieee80211_valid_disable_subchannel_bitmap(u16 *bitmap,
+						      enum nl80211_chan_width bw)
+{
+	u32 idx, i;
+
+	switch (bw) {
+	case NL80211_CHAN_WIDTH_80:
+		idx = 0;
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		idx = 1;
+		break;
+	case NL80211_CHAN_WIDTH_320:
+		idx = 2;
+		break;
+	default:
+		*bitmap = 0;
+		break;
+	}
+
+	if (!*bitmap)
+		return true;
+
+	for (i = 0; i < per_bw_puncturing[idx].len; i++)
+		if (per_bw_puncturing[idx].valid_values[i] == *bitmap)
+			return true;
+
+	return false;
+}
+
+/*
+ * Extract from the given disabled subchannel bitmap (raw format
+ * from the EHT Operation Element) the bits for the subchannel
+ * we're using right now.
+ */
+static u16
+ieee80211_extract_dis_subch_bmap(const struct ieee80211_eht_operation *eht_oper,
+				 struct cfg80211_chan_def *chandef, u16 bitmap)
+{
+	struct ieee80211_eht_operation_info *info = (void *)eht_oper->optional;
+	struct cfg80211_chan_def ap_chandef = *chandef;
+	u32 ap_center_freq, local_center_freq;
+	u32 ap_bw, local_bw;
+	int ap_start_freq, local_start_freq;
+	u16 shift, mask;
+
+	if (!(eht_oper->params & IEEE80211_EHT_OPER_INFO_PRESENT) ||
+	    !(eht_oper->params &
+	      IEEE80211_EHT_OPER_DISABLED_SUBCHANNEL_BITMAP_PRESENT))
+		return 0;
+
+	/* set 160/320 supported to get the full AP definition */
+	ieee80211_chandef_eht_oper(eht_oper, true, true, &ap_chandef);
+	ap_center_freq = ap_chandef.center_freq1;
+	ap_bw = 20 * BIT(u8_get_bits(info->control,
+				     IEEE80211_EHT_OPER_CHAN_WIDTH));
+	ap_start_freq = ap_center_freq - ap_bw / 2;
+	local_center_freq = chandef->center_freq1;
+	local_bw = 20 * BIT(ieee80211_chan_width_to_rx_bw(chandef->width));
+	local_start_freq = local_center_freq - local_bw / 2;
+	shift = (local_start_freq - ap_start_freq) / 20;
+	mask = BIT(local_bw / 20) - 1;
+
+	return (bitmap >> shift) & mask;
+}
+
+/*
+ * Handle the puncturing bitmap, possibly downgrading bandwidth to get a
+ * valid bitmap.
+ */
+static void
+ieee80211_handle_puncturing_bitmap(struct ieee80211_link_data *link,
+				   const struct ieee80211_eht_operation *eht_oper,
+				   u16 bitmap, u64 *changed)
+{
+	struct cfg80211_chan_def *chandef = &link->conf->chandef;
+	u16 extracted;
+	u64 _changed = 0;
+
+	if (!changed)
+		changed = &_changed;
+
+	while (chandef->width > NL80211_CHAN_WIDTH_40) {
+		extracted =
+			ieee80211_extract_dis_subch_bmap(eht_oper, chandef,
+							 bitmap);
+
+		if (ieee80211_valid_disable_subchannel_bitmap(&bitmap,
+							      chandef->width))
+			break;
+		link->u.mgd.conn_flags |=
+			ieee80211_chandef_downgrade(chandef);
+		*changed |= BSS_CHANGED_BANDWIDTH;
+	}
+
+	if (chandef->width <= NL80211_CHAN_WIDTH_40)
+		extracted = 0;
+
+	if (link->conf->eht_puncturing != extracted) {
+		link->conf->eht_puncturing = extracted;
+		*changed |= BSS_CHANGED_EHT_PUNCTURING;
+	}
+}
+
 /*
  * We can have multiple work items (and connection probing)
  * scheduling this timer, but we need to take care to only
@@ -413,7 +548,7 @@ static int ieee80211_config_bw(struct ieee80211_link_data *link,
 			       const struct ieee80211_he_operation *he_oper,
 			       const struct ieee80211_eht_operation *eht_oper,
 			       const struct ieee80211_s1g_oper_ie *s1g_oper,
-			       const u8 *bssid, u32 *changed)
+			       const u8 *bssid, u64 *changed)
 {
 	struct ieee80211_sub_if_data *sdata = link->sdata;
 	struct ieee80211_local *local = sdata->local;
@@ -4145,6 +4280,7 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 							    link_sta);
 
 			bss_conf->eht_support = link_sta->pub->eht_cap.has_eht;
+			*changed |= BSS_CHANGED_EHT_PUNCTURING;
 		} else {
 			bss_conf->eht_support = false;
 		}
@@ -5477,6 +5613,45 @@ static bool ieee80211_rx_our_beacon(const u8 *tx_bssid,
 	return ether_addr_equal(tx_bssid, bss->transmitted_bss->bssid);
 }
 
+static bool ieee80211_config_puncturing(struct ieee80211_link_data *link,
+					const struct ieee80211_eht_operation *eht_oper,
+					u64 *changed)
+{
+	u16 bitmap = 0, extracted;
+
+	if ((eht_oper->params & IEEE80211_EHT_OPER_INFO_PRESENT) &&
+	    (eht_oper->params &
+	     IEEE80211_EHT_OPER_DISABLED_SUBCHANNEL_BITMAP_PRESENT)) {
+		const struct ieee80211_eht_operation_info *info =
+			(void *)eht_oper->optional;
+		const u8 *disable_subchannel_bitmap = info->optional;
+
+		bitmap = get_unaligned_le16(disable_subchannel_bitmap);
+	}
+
+	extracted = ieee80211_extract_dis_subch_bmap(eht_oper,
+						     &link->conf->chandef,
+						     bitmap);
+
+	/* accept if there are no changes */
+	if (!(*changed & BSS_CHANGED_BANDWIDTH) &&
+	    extracted == link->conf->eht_puncturing)
+		return true;
+
+	if (!ieee80211_valid_disable_subchannel_bitmap(&bitmap,
+						       link->conf->chandef.width)) {
+		link_info(link,
+			  "Got an invalid disable subchannel bitmap from AP %pM: bitmap = 0x%x, bw = 0x%x. disconnect\n",
+			  link->u.mgd.bssid,
+			  bitmap,
+			  link->conf->chandef.width);
+		return false;
+	}
+
+	ieee80211_handle_puncturing_bitmap(link, eht_oper, bitmap, changed);
+	return true;
+}
+
 static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 				     struct ieee80211_hdr *hdr, size_t len,
 				     struct ieee80211_rx_status *rx_status)
@@ -5494,7 +5669,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 	struct ieee80211_channel *chan;
 	struct link_sta_info *link_sta;
 	struct sta_info *sta;
-	u32 changed = 0;
+	u64 changed = 0;
 	bool erp_valid;
 	u8 erp_value = 0;
 	u32 ncrc = 0;
@@ -5791,6 +5966,21 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 					       elems->pwr_constr_elem,
 					       elems->cisco_dtpc_elem);
 
+	if (elems->eht_operation &&
+	    !(link->u.mgd.conn_flags & IEEE80211_CONN_DISABLE_EHT)) {
+		if (!ieee80211_config_puncturing(link, elems->eht_operation,
+						 &changed)) {
+			ieee80211_set_disassoc(sdata, IEEE80211_STYPE_DEAUTH,
+					       WLAN_REASON_DEAUTH_LEAVING,
+					       true, deauth_buf);
+			ieee80211_report_disconnect(sdata, deauth_buf,
+						    sizeof(deauth_buf), true,
+						    WLAN_REASON_DEAUTH_LEAVING,
+						    false);
+			goto free;
+		}
+	}
+
 	ieee80211_link_info_change_notify(sdata, link, changed);
 free:
 	kfree(elems);
@@ -6892,9 +7082,12 @@ ieee80211_setup_assoc_link(struct ieee80211_sub_if_data *sdata,
 		ieee80211_apply_htcap_overrides(sdata, &sta_ht_cap);
 	}
 
+	link->conf->eht_puncturing = 0;
+
 	rcu_read_lock();
 	beacon_ies = rcu_dereference(cbss->beacon_ies);
 	if (beacon_ies) {
+		const struct ieee80211_eht_operation *eht_oper;
 		const struct element *elem;
 		u8 dtim_count = 0;
 
@@ -6923,6 +7116,31 @@ ieee80211_setup_assoc_link(struct ieee80211_sub_if_data *sdata,
 			link->conf->ema_ap = true;
 		else
 			link->conf->ema_ap = false;
+
+		elem = cfg80211_find_ext_elem(WLAN_EID_EXT_EHT_OPERATION,
+					      beacon_ies->data, beacon_ies->len);
+		eht_oper = (const void *)(elem->data + 1);
+
+		if (elem &&
+		    ieee80211_eht_oper_size_ok((const void *)(elem->data + 1),
+					       elem->datalen - 1) &&
+		    (eht_oper->params & IEEE80211_EHT_OPER_INFO_PRESENT) &&
+		    (eht_oper->params & IEEE80211_EHT_OPER_DISABLED_SUBCHANNEL_BITMAP_PRESENT)) {
+			const struct ieee80211_eht_operation_info *info =
+				(void *)eht_oper->optional;
+			const u8 *disable_subchannel_bitmap = info->optional;
+			u16 bitmap;
+
+			bitmap = get_unaligned_le16(disable_subchannel_bitmap);
+			if (ieee80211_valid_disable_subchannel_bitmap(&bitmap,
+								      link->conf->chandef.width))
+				ieee80211_handle_puncturing_bitmap(link,
+								   eht_oper,
+								   bitmap,
+								   NULL);
+			else
+				conn_flags |= IEEE80211_CONN_DISABLE_EHT;
+		}
 	}
 	rcu_read_unlock();
 
-- 
2.39.1