wifi: mac80211: clean up connection process

Rewrite the station-side connection handling. The connection
flags (IEEE80211_DISABLE_*) are rather confusing, and they're
not always maintained well. Additionally, for wider-bandwidth
OFDMA support we need to know the precise bandwidth of the AP,
which is currently somewhat difficult.

Rewrite this to have a 'mode' (S1G/legacy/HT/...) and a limit
on the bandwidth. This is not entirely clean because some of
those modes aren't completely sequenced (as this assumes in
some places), e.g. VHT doesn't exist on 2.4 GHz, but HE does.
However, it still simplifies things and gives us a good idea
what we're operating as, so we can parse elements accordingly
etc.

This leaves a FIXME for puncturing, this is addressed in a
later patch.

Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240129194108.9451722c0110.I3e61f4cfe9da89008e1854160093c76a1e69dc2a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 134 insertions, 30 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 685b55a053f3..1d504c8e6bfc 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -46,6 +46,11 @@ struct ieee80211_hw *wiphy_to_ieee80211_hw(struct wiphy *wiphy)
 }
 EXPORT_SYMBOL(wiphy_to_ieee80211_hw);
 
+const struct ieee80211_conn_settings ieee80211_conn_settings_unlimited = {
+	.mode = IEEE80211_CONN_MODE_EHT,
+	.bw_limit = IEEE80211_CONN_BW_LIMIT_320,
+};
+
 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
 			enum nl80211_iftype type)
 {
@@ -929,23 +934,31 @@ ieee80211_parse_extension_element(u32 *crc,
 
 	switch (elem->data[0]) {
 	case WLAN_EID_EXT_HE_MU_EDCA:
+		if (params->mode < IEEE80211_CONN_MODE_HE)
+			break;
 		calc_crc = true;
 		if (len >= sizeof(*elems->mu_edca_param_set))
 			elems->mu_edca_param_set = data;
 		break;
 	case WLAN_EID_EXT_HE_CAPABILITY:
+		if (params->mode < IEEE80211_CONN_MODE_HE)
+			break;
 		if (ieee80211_he_capa_size_ok(data, len)) {
 			elems->he_cap = data;
 			elems->he_cap_len = len;
 		}
 		break;
 	case WLAN_EID_EXT_HE_OPERATION:
+		if (params->mode < IEEE80211_CONN_MODE_HE)
+			break;
 		calc_crc = true;
 		if (len >= sizeof(*elems->he_operation) &&
 		    len >= ieee80211_he_oper_size(data) - 1)
 			elems->he_operation = data;
 		break;
 	case WLAN_EID_EXT_UORA:
+		if (params->mode < IEEE80211_CONN_MODE_HE)
+			break;
 		if (len >= 1)
 			elems->uora_element = data;
 		break;
@@ -958,15 +971,21 @@ ieee80211_parse_extension_element(u32 *crc,
 			elems->mbssid_config_ie = data;
 		break;
 	case WLAN_EID_EXT_HE_SPR:
+		if (params->mode < IEEE80211_CONN_MODE_HE)
+			break;
 		if (len >= sizeof(*elems->he_spr) &&
 		    len >= ieee80211_he_spr_size(data))
 			elems->he_spr = data;
 		break;
 	case WLAN_EID_EXT_HE_6GHZ_CAPA:
+		if (params->mode < IEEE80211_CONN_MODE_HE)
+			break;
 		if (len >= sizeof(*elems->he_6ghz_capa))
 			elems->he_6ghz_capa = data;
 		break;
 	case WLAN_EID_EXT_EHT_CAPABILITY:
+		if (params->mode < IEEE80211_CONN_MODE_EHT)
+			break;
 		if (ieee80211_eht_capa_size_ok(elems->he_cap,
 					       data, len,
 					       params->from_ap)) {
@@ -975,11 +994,15 @@ ieee80211_parse_extension_element(u32 *crc,
 		}
 		break;
 	case WLAN_EID_EXT_EHT_OPERATION:
+		if (params->mode < IEEE80211_CONN_MODE_EHT)
+			break;
 		if (ieee80211_eht_oper_size_ok(data, len))
 			elems->eht_operation = data;
 		calc_crc = true;
 		break;
 	case WLAN_EID_EXT_EHT_MULTI_LINK:
+		if (params->mode < IEEE80211_CONN_MODE_EHT)
+			break;
 		calc_crc = true;
 
 		if (ieee80211_mle_size_ok(data, len)) {
@@ -1004,11 +1027,15 @@ ieee80211_parse_extension_element(u32 *crc,
 		}
 		break;
 	case WLAN_EID_EXT_BANDWIDTH_INDICATION:
+		if (params->mode < IEEE80211_CONN_MODE_EHT)
+			break;
 		if (ieee80211_bandwidth_indication_size_ok(data, len))
 			elems->bandwidth_indication = data;
 		calc_crc = true;
 		break;
 	case WLAN_EID_EXT_TID_TO_LINK_MAPPING:
+		if (params->mode < IEEE80211_CONN_MODE_EHT)
+			break;
 		calc_crc = true;
 		if (ieee80211_tid_to_link_map_size_ok(data, len) &&
 		    elems->ttlm_num < ARRAY_SIZE(elems->ttlm)) {
@@ -1178,24 +1205,32 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 			elems->ext_supp_rates_len = elen;
 			break;
 		case WLAN_EID_HT_CAPABILITY:
+			if (params->mode < IEEE80211_CONN_MODE_HT)
+				break;
 			if (elen >= sizeof(struct ieee80211_ht_cap))
 				elems->ht_cap_elem = (void *)pos;
 			else
 				elem_parse_failed = true;
 			break;
 		case WLAN_EID_HT_OPERATION:
+			if (params->mode < IEEE80211_CONN_MODE_HT)
+				break;
 			if (elen >= sizeof(struct ieee80211_ht_operation))
 				elems->ht_operation = (void *)pos;
 			else
 				elem_parse_failed = true;
 			break;
 		case WLAN_EID_VHT_CAPABILITY:
+			if (params->mode < IEEE80211_CONN_MODE_VHT)
+				break;
 			if (elen >= sizeof(struct ieee80211_vht_cap))
 				elems->vht_cap_elem = (void *)pos;
 			else
 				elem_parse_failed = true;
 			break;
 		case WLAN_EID_VHT_OPERATION:
+			if (params->mode < IEEE80211_CONN_MODE_VHT)
+				break;
 			if (elen >= sizeof(struct ieee80211_vht_operation)) {
 				elems->vht_operation = (void *)pos;
 				if (calc_crc)
@@ -1205,6 +1240,8 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 			elem_parse_failed = true;
 			break;
 		case WLAN_EID_OPMODE_NOTIF:
+			if (params->mode < IEEE80211_CONN_MODE_VHT)
+				break;
 			if (elen > 0) {
 				elems->opmode_notif = pos;
 				if (calc_crc)
@@ -1264,6 +1301,8 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 			elems->ext_chansw_ie = (void *)pos;
 			break;
 		case WLAN_EID_SECONDARY_CHANNEL_OFFSET:
+			if (params->mode < IEEE80211_CONN_MODE_HT)
+				break;
 			if (elen != sizeof(struct ieee80211_sec_chan_offs_ie)) {
 				elem_parse_failed = true;
 				break;
@@ -1279,6 +1318,8 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 			elems->mesh_chansw_params_ie = (void *)pos;
 			break;
 		case WLAN_EID_WIDE_BW_CHANNEL_SWITCH:
+			if (params->mode < IEEE80211_CONN_MODE_VHT)
+				break;
 			if (!params->action ||
 			    elen < sizeof(*elems->wide_bw_chansw_ie)) {
 				elem_parse_failed = true;
@@ -1287,6 +1328,8 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 			elems->wide_bw_chansw_ie = (void *)pos;
 			break;
 		case WLAN_EID_CHANNEL_SWITCH_WRAPPER:
+			if (params->mode < IEEE80211_CONN_MODE_VHT)
+				break;
 			if (params->action) {
 				elem_parse_failed = true;
 				break;
@@ -1305,6 +1348,9 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 					elem_parse_failed = true;
 			}
 
+			if (params->mode < IEEE80211_CONN_MODE_EHT)
+				break;
+
 			subelem = cfg80211_find_ext_elem(WLAN_EID_EXT_BANDWIDTH_INDICATION,
 							 pos, elen);
 			if (subelem) {
@@ -1393,24 +1439,32 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 							  elem, elems, params);
 			break;
 		case WLAN_EID_S1G_CAPABILITIES:
+			if (params->mode != IEEE80211_CONN_MODE_S1G)
+				break;
 			if (elen >= sizeof(*elems->s1g_capab))
 				elems->s1g_capab = (void *)pos;
 			else
 				elem_parse_failed = true;
 			break;
 		case WLAN_EID_S1G_OPERATION:
+			if (params->mode != IEEE80211_CONN_MODE_S1G)
+				break;
 			if (elen == sizeof(*elems->s1g_oper))
 				elems->s1g_oper = (void *)pos;
 			else
 				elem_parse_failed = true;
 			break;
 		case WLAN_EID_S1G_BCN_COMPAT:
+			if (params->mode != IEEE80211_CONN_MODE_S1G)
+				break;
 			if (elen == sizeof(*elems->s1g_bcn_compat))
 				elems->s1g_bcn_compat = (void *)pos;
 			else
 				elem_parse_failed = true;
 			break;
 		case WLAN_EID_AID_RESPONSE:
+			if (params->mode != IEEE80211_CONN_MODE_S1G)
+				break;
 			if (elen == sizeof(struct ieee80211_aid_response_ie))
 				elems->aid_resp = (void *)pos;
 			else
@@ -1562,6 +1616,7 @@ static void ieee80211_mle_parse_link(struct ieee802_11_elems *elems,
 {
 	struct ieee80211_mle_per_sta_profile *prof;
 	struct ieee80211_elems_parse_params sub = {
+		.mode = params->mode,
 		.action = params->action,
 		.from_ap = params->from_ap,
 		.link_id = -1,
@@ -1649,6 +1704,7 @@ ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params)
 	/* Override with nontransmitted profile, if found */
 	if (nontransmitted_profile_len) {
 		struct ieee80211_elems_parse_params sub = {
+			.mode = params->mode,
 			.start = nontransmitted_profile,
 			.len = nontransmitted_profile_len,
 			.action = params->action,
@@ -2142,7 +2198,7 @@ static int ieee80211_build_preq_ies_band(struct ieee80211_sub_if_data *sdata,
 	if (he_cap &&
 	    cfg80211_any_usable_channels(local->hw.wiphy, BIT(sband->band),
 					 IEEE80211_CHAN_NO_HE)) {
-		pos = ieee80211_ie_build_he_cap(0, pos, he_cap, end);
+		pos = ieee80211_ie_build_he_cap(NULL, he_cap, pos, end);
 		if (!pos)
 			goto out_err;
 	}
@@ -3201,15 +3257,18 @@ u8 ieee80211_ie_len_he_cap(struct ieee80211_sub_if_data *sdata, u8 iftype)
 				     he_cap->he_cap_elem.phy_cap_info);
 }
 
-u8 *ieee80211_ie_build_he_cap(ieee80211_conn_flags_t disable_flags, u8 *pos,
+u8 *ieee80211_ie_build_he_cap(const struct ieee80211_conn_settings *conn,
 			      const struct ieee80211_sta_he_cap *he_cap,
-			      u8 *end)
+			      u8 *pos, u8 *end)
 {
 	struct ieee80211_he_cap_elem elem;
 	u8 n;
 	u8 ie_len;
 	u8 *orig_pos = pos;
 
+	if (!conn)
+		conn = &ieee80211_conn_settings_unlimited;
+
 	/* Make sure we have place for the IE */
 	/*
 	 * TODO: the 1 added is because this temporarily is under the EXTENSION
@@ -3221,18 +3280,15 @@ u8 *ieee80211_ie_build_he_cap(ieee80211_conn_flags_t disable_flags, u8 *pos,
 	/* modify on stack first to calculate 'n' and 'ie_len' correctly */
 	elem = he_cap->he_cap_elem;
 
-	if (disable_flags & IEEE80211_CONN_DISABLE_40MHZ)
+	if (conn->bw_limit < IEEE80211_CONN_BW_LIMIT_40)
 		elem.phy_cap_info[0] &=
 			~(IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_40MHZ_80MHZ_IN_5G |
 			  IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_40MHZ_IN_2G);
 
-	if (disable_flags & IEEE80211_CONN_DISABLE_160MHZ)
+	if (conn->bw_limit < IEEE80211_CONN_BW_LIMIT_160)
 		elem.phy_cap_info[0] &=
-			~IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_160MHZ_IN_5G;
-
-	if (disable_flags & IEEE80211_CONN_DISABLE_80P80MHZ)
-		elem.phy_cap_info[0] &=
-			~IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_80PLUS80_MHZ_IN_5G;
+			~(IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_160MHZ_IN_5G |
+			  IEEE80211_HE_PHY_CAP0_CHANNEL_WIDTH_SET_80PLUS80_MHZ_IN_5G);
 
 	n = ieee80211_he_mcs_nss_size(&elem);
 	ie_len = 2 + 1 +
@@ -4367,21 +4423,32 @@ void ieee80211_radar_detected(struct ieee80211_hw *hw)
 }
 EXPORT_SYMBOL(ieee80211_radar_detected);
 
-ieee80211_conn_flags_t ieee80211_chandef_downgrade(struct cfg80211_chan_def *c)
+void ieee80211_chandef_downgrade(struct cfg80211_chan_def *c,
+				 struct ieee80211_conn_settings *conn)
 {
-	ieee80211_conn_flags_t ret;
+	struct ieee80211_conn_settings _ignored = {};
 	int tmp;
 
+	/* allow passing NULL if caller doesn't care */
+	if (!conn)
+		conn = &_ignored;
+
 	switch (c->width) {
+	default:
+	case NL80211_CHAN_WIDTH_20_NOHT:
+		WARN_ON_ONCE(1);
+		fallthrough;
 	case NL80211_CHAN_WIDTH_20:
 		c->width = NL80211_CHAN_WIDTH_20_NOHT;
-		ret = IEEE80211_CONN_DISABLE_HT | IEEE80211_CONN_DISABLE_VHT;
+		conn->mode = IEEE80211_CONN_MODE_LEGACY;
+		conn->bw_limit = IEEE80211_CONN_BW_LIMIT_20;
 		break;
 	case NL80211_CHAN_WIDTH_40:
 		c->width = NL80211_CHAN_WIDTH_20;
 		c->center_freq1 = c->chan->center_freq;
-		ret = IEEE80211_CONN_DISABLE_40MHZ |
-		      IEEE80211_CONN_DISABLE_VHT;
+		if (conn->mode == IEEE80211_CONN_MODE_VHT)
+			conn->mode = IEEE80211_CONN_MODE_HT;
+		conn->bw_limit = IEEE80211_CONN_BW_LIMIT_20;
 		break;
 	case NL80211_CHAN_WIDTH_80:
 		tmp = (30 + c->chan->center_freq - c->center_freq1)/20;
@@ -4390,13 +4457,14 @@ ieee80211_conn_flags_t ieee80211_chandef_downgrade(struct cfg80211_chan_def *c)
 		/* freq_P40 */
 		c->center_freq1 = c->center_freq1 - 20 + 40 * tmp;
 		c->width = NL80211_CHAN_WIDTH_40;
-		ret = IEEE80211_CONN_DISABLE_VHT;
+		if (conn->mode == IEEE80211_CONN_MODE_VHT)
+			conn->mode = IEEE80211_CONN_MODE_HT;
+		conn->bw_limit = IEEE80211_CONN_BW_LIMIT_40;
 		break;
 	case NL80211_CHAN_WIDTH_80P80:
 		c->center_freq2 = 0;
 		c->width = NL80211_CHAN_WIDTH_80;
-		ret = IEEE80211_CONN_DISABLE_80P80MHZ |
-		      IEEE80211_CONN_DISABLE_160MHZ;
+		conn->bw_limit = IEEE80211_CONN_BW_LIMIT_80;
 		break;
 	case NL80211_CHAN_WIDTH_160:
 		/* n_P20 */
@@ -4405,8 +4473,7 @@ ieee80211_conn_flags_t ieee80211_chandef_downgrade(struct cfg80211_chan_def *c)
 		tmp /= 4;
 		c->center_freq1 = c->center_freq1 - 40 + 80 * tmp;
 		c->width = NL80211_CHAN_WIDTH_80;
-		ret = IEEE80211_CONN_DISABLE_80P80MHZ |
-		      IEEE80211_CONN_DISABLE_160MHZ;
+		conn->bw_limit = IEEE80211_CONN_BW_LIMIT_80;
 		break;
 	case NL80211_CHAN_WIDTH_320:
 		/* n_P20 */
@@ -4415,30 +4482,28 @@ ieee80211_conn_flags_t ieee80211_chandef_downgrade(struct cfg80211_chan_def *c)
 		tmp /= 8;
 		c->center_freq1 = c->center_freq1 - 80 + 160 * tmp;
 		c->width = NL80211_CHAN_WIDTH_160;
-		ret = IEEE80211_CONN_DISABLE_320MHZ;
-		break;
-	default:
-	case NL80211_CHAN_WIDTH_20_NOHT:
-		WARN_ON_ONCE(1);
-		c->width = NL80211_CHAN_WIDTH_20_NOHT;
-		ret = IEEE80211_CONN_DISABLE_HT | IEEE80211_CONN_DISABLE_VHT;
+		conn->bw_limit = IEEE80211_CONN_BW_LIMIT_160;
 		break;
 	case NL80211_CHAN_WIDTH_1:
 	case NL80211_CHAN_WIDTH_2:
 	case NL80211_CHAN_WIDTH_4:
 	case NL80211_CHAN_WIDTH_8:
 	case NL80211_CHAN_WIDTH_16:
+		WARN_ON_ONCE(1);
+		/* keep c->width */
+		conn->mode = IEEE80211_CONN_MODE_S1G;
+		conn->bw_limit = IEEE80211_CONN_BW_LIMIT_20;
+		break;
 	case NL80211_CHAN_WIDTH_5:
 	case NL80211_CHAN_WIDTH_10:
 		WARN_ON_ONCE(1);
 		/* keep c->width */
-		ret = IEEE80211_CONN_DISABLE_HT | IEEE80211_CONN_DISABLE_VHT;
+		conn->mode = IEEE80211_CONN_MODE_LEGACY;
+		conn->bw_limit = IEEE80211_CONN_BW_LIMIT_20;
 		break;
 	}
 
 	WARN_ON_ONCE(!cfg80211_chandef_valid(c));
-
-	return ret;
 }
 
 /*
@@ -5090,3 +5155,42 @@ u8 *ieee80211_ie_build_eht_cap(u8 *pos,
 
 	return pos;
 }
+
+const char *ieee80211_conn_mode_str(enum ieee80211_conn_mode mode)
+{
+	static const char * const modes[] = {
+		[IEEE80211_CONN_MODE_S1G] = "S1G",
+		[IEEE80211_CONN_MODE_LEGACY] = "legacy",
+		[IEEE80211_CONN_MODE_HT] = "HT",
+		[IEEE80211_CONN_MODE_VHT] = "VHT",
+		[IEEE80211_CONN_MODE_HE] = "HE",
+		[IEEE80211_CONN_MODE_EHT] = "EHT",
+	};
+
+	if (WARN_ON(mode >= ARRAY_SIZE(modes)))
+		return "<out of range>";
+
+	return modes[mode] ?: "<missing string>";
+}
+
+enum ieee80211_conn_bw_limit
+ieee80211_min_bw_limit_from_chandef(struct cfg80211_chan_def *chandef)
+{
+	switch (chandef->width) {
+	case NL80211_CHAN_WIDTH_20_NOHT:
+	case NL80211_CHAN_WIDTH_20:
+		return IEEE80211_CONN_BW_LIMIT_20;
+	case NL80211_CHAN_WIDTH_40:
+		return IEEE80211_CONN_BW_LIMIT_40;
+	case NL80211_CHAN_WIDTH_80:
+		return IEEE80211_CONN_BW_LIMIT_80;
+	case NL80211_CHAN_WIDTH_80P80:
+	case NL80211_CHAN_WIDTH_160:
+		return IEEE80211_CONN_BW_LIMIT_160;
+	case NL80211_CHAN_WIDTH_320:
+		return IEEE80211_CONN_BW_LIMIT_320;
+	default:
+		WARN(1, "unhandled chandef width %d\n", chandef->width);
+		return IEEE80211_CONN_BW_LIMIT_20;
+	}
+}