wifi: mac80211: Add eMLSR/eMLMR action frame parsing support

Introduce support in AP mode for parsing of the Operating Mode Notification
frame sent by the client to enable/disable MLO eMLSR or eMLMR if supported
by both the AP and the client.
Add drv_set_eml_op_mode mac80211 callback in order to configure underlay
driver with eMLSR/eMLMR info.

Tested-by: Christian Marangi <[e-mail]>
Signed-off-by: Lorenzo Bianconi <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Johannes Berg <[e-mail]>

include/linux/ieee80211-eht.h

···
 
 #define IEEE80211_MLC_PRIO_ACCESS_PRES_AP_MLD_MAC_ADDR	0x0010
 
+#define IEEE80211_EML_CTRL_EMLSR_MODE		BIT(0)
+#define IEEE80211_EML_CTRL_EMLMR_MODE		BIT(1)
+#define IEEE80211_EML_CTRL_EMLSR_PARAM_UPDATE	BIT(2)
+#define IEEE80211_EML_CTRL_INDEV_COEX_ACT	BIT(3)
+
+#define IEEE80211_EML_EMLSR_PAD_DELAY		0x07
+#define IEEE80211_EML_EMLSR_TRANS_DELAY		0x38
+
+#define IEEE80211_EML_EMLMR_RX_MCS_MAP		0xf0
+#define IEEE80211_EML_EMLMR_TX_MCS_MAP		0x0f
+
 /* no fixed fields in PRIO_ACCESS */
 
 /**

include/linux/ieee80211.h

···
 					u8 action_code;
 					u8 variable[];
 				} __packed epcs;
+				struct {
+					u8 action_code;
+					u8 dialog_token;
+					u8 control;
+					u8 variable[];
+				} __packed eml_omn;
 			} u;
 		} __packed action;
 		DECLARE_FLEX_ARRAY(u8, body); /* Generic frame body */

include/net/mac80211.h

···
 };
 
 /**
+ * struct ieee80211_eml_params - EHT Operating mode notification parameters
+ *
+ * EML Operating mode notification parameters received in the Operating mode
+ * notification frame. This struct is used as a container to pass the info to
+ * the underlay driver.
+ *
+ * @link_id: the link ID where the Operating mode notification frame has been
+ *	received.
+ * @control: EML control field defined in P802.11be section 9.4.1.76.
+ * @link_bitmap: eMLSR/eMLMR enabled links defined in P802.11be
+ *	section 9.4.1.76.
+ * @emlmr_mcs_map_count: eMLMR number of valid mcs_map_bw fields according to
+ *	P802.11be section 9.4.1.76 (valid if eMLMR mode control bit is set).
+ * @emlmr_mcs_map_bw: eMLMR supported MCS and NSS set subfileds defined in
+ *	P802.11be section 9.4.1.76 (valid if eMLMR mode control bit is set).
+ */
+struct ieee80211_eml_params {
+	u8 link_id;
+	u8 control;
+	u16 link_bitmap;
+	u8 emlmr_mcs_map_count;
+	u8 emlmr_mcs_map_bw[9];
+};
+
+/**
  * struct ieee80211_vif_cfg - interface configuration
  * @assoc: association status
  * @ibss_joined: indicates whether this station is part of an IBSS or not
···
  *      interface with the specified type would be added, and thus drivers that
  *      implement this callback need to handle such cases. The type is the full
  *      &enum nl80211_iftype.
+ * @set_eml_op_mode: Configure eMLSR/eMLMR operation mode in the underlay
+ *	driver according to the parameter received in the EML Operating mode
+ *	notification frame.
  */
 struct ieee80211_ops {
 	void (*tx)(struct ieee80211_hw *hw,
···
 			struct ieee80211_neg_ttlm *ttlm);
 	void (*prep_add_interface)(struct ieee80211_hw *hw,
 				   enum nl80211_iftype type);
+	int (*set_eml_op_mode)(struct ieee80211_hw *hw,
+			       struct ieee80211_vif *vif,
+			       struct ieee80211_sta *sta,
+			       struct ieee80211_eml_params *eml_params);
 };
 
 /**

net/mac80211/driver-ops.h

···
 	trace_drv_return_void(local);
 }
 
+static inline int drv_set_eml_op_mode(struct ieee80211_sub_if_data *sdata,
+				      struct ieee80211_sta *sta,
+				      struct ieee80211_eml_params *eml_params)
+{
+	struct ieee80211_local *local = sdata->local;
+	int ret = -EOPNOTSUPP;
+
+	might_sleep();
+	lockdep_assert_wiphy(local->hw.wiphy);
+
+	trace_drv_set_eml_op_mode(local, sdata, sta, eml_params->link_id,
+				  eml_params->control,
+				  eml_params->link_bitmap);
+	if (local->ops->set_eml_op_mode)
+		ret = local->ops->set_eml_op_mode(&local->hw, &sdata->vif,
+						  sta, eml_params);
+	trace_drv_return_int(local, ret);
+
+	return ret;
+}
+
 #endif /* __MAC80211_DRIVER_OPS */

net/mac80211/eht.c

···
  * Copyright(c) 2021-2025 Intel Corporation
  */
 
+#include "driver-ops.h"
 #include "ieee80211_i.h"
 
 void
···
 	}
 
 	ieee80211_sta_recalc_aggregates(&link_sta->sta->sta);
+}
+
+static void
+ieee80211_send_eml_op_mode_notif(struct ieee80211_sub_if_data *sdata,
+				 struct ieee80211_mgmt *req, int opt_len)
+{
+	int len = offsetofend(struct ieee80211_mgmt, u.action.u.eml_omn);
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_mgmt *mgmt;
+	struct sk_buff *skb;
+
+	len += opt_len; /* optional len */
+	skb = dev_alloc_skb(local->tx_headroom + len);
+	if (!skb)
+		return;
+
+	skb_reserve(skb, local->tx_headroom);
+	mgmt = skb_put_zero(skb, len);
+	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
+					  IEEE80211_STYPE_ACTION);
+	memcpy(mgmt->da, req->sa, ETH_ALEN);
+	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
+	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
+
+	mgmt->u.action.category = WLAN_CATEGORY_PROTECTED_EHT;
+	mgmt->u.action.u.eml_omn.action_code =
+		WLAN_PROTECTED_EHT_ACTION_EML_OP_MODE_NOTIF;
+	mgmt->u.action.u.eml_omn.dialog_token =
+		req->u.action.u.eml_omn.dialog_token;
+	mgmt->u.action.u.eml_omn.control = req->u.action.u.eml_omn.control &
+		~(IEEE80211_EML_CTRL_EMLSR_PARAM_UPDATE |
+		  IEEE80211_EML_CTRL_INDEV_COEX_ACT);
+	/* Copy optional fields from the received notification frame */
+	memcpy(mgmt->u.action.u.eml_omn.variable,
+	       req->u.action.u.eml_omn.variable, opt_len);
+
+	ieee80211_tx_skb(sdata, skb);
+}
+
+void ieee80211_rx_eml_op_mode_notif(struct ieee80211_sub_if_data *sdata,
+				    struct sk_buff *skb)
+{
+	int len = offsetofend(struct ieee80211_mgmt, u.action.u.eml_omn);
+	enum nl80211_iftype type = ieee80211_vif_type_p2p(&sdata->vif);
+	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
+	const struct wiphy_iftype_ext_capab *ift_ext_capa;
+	struct ieee80211_mgmt *mgmt = (void *)skb->data;
+	struct ieee80211_local *local = sdata->local;
+	u8 control = mgmt->u.action.u.eml_omn.control;
+	u8 *ptr = mgmt->u.action.u.eml_omn.variable;
+	struct ieee80211_eml_params eml_params = {
+		.link_id = status->link_id,
+	};
+	struct sta_info *sta;
+	int opt_len = 0;
+
+	if (!ieee80211_vif_is_mld(&sdata->vif))
+		return;
+
+	/* eMLSR and eMLMR can't be enabled at the same time */
+	if ((control & IEEE80211_EML_CTRL_EMLSR_MODE) &&
+	    (control & IEEE80211_EML_CTRL_EMLMR_MODE))
+		return;
+
+	if ((control & IEEE80211_EML_CTRL_EMLMR_MODE) &&
+	    (control & IEEE80211_EML_CTRL_EMLSR_PARAM_UPDATE))
+		return;
+
+	ift_ext_capa = cfg80211_get_iftype_ext_capa(local->hw.wiphy, type);
+	if (!ift_ext_capa)
+		return;
+
+	if (!status->link_valid)
+		return;
+
+	sta = sta_info_get_bss(sdata, mgmt->sa);
+	if (!sta)
+		return;
+
+	if (control & IEEE80211_EML_CTRL_EMLSR_MODE) {
+		u8 emlsr_param_update_len;
+
+		if (!(ift_ext_capa->eml_capabilities &
+		      IEEE80211_EML_CAP_EMLSR_SUPP))
+			return;
+
+		opt_len += sizeof(__le16); /* eMLSR link_bitmap */
+		/* eMLSR param update field is not part of Notfication frame
+		 * sent by the AP to client so account it separately.
+		 */
+		emlsr_param_update_len =
+			!!(control & IEEE80211_EML_CTRL_EMLSR_PARAM_UPDATE);
+
+		if (skb->len < len + opt_len + emlsr_param_update_len)
+			return;
+
+		if (control & IEEE80211_EML_CTRL_EMLSR_PARAM_UPDATE) {
+			u8 pad_delay, trans_delay;
+
+			pad_delay = u8_get_bits(ptr[2],
+						IEEE80211_EML_EMLSR_PAD_DELAY);
+			if (pad_delay >
+			    IEEE80211_EML_CAP_EMLSR_PADDING_DELAY_256US)
+				return;
+
+			trans_delay = u8_get_bits(ptr[2],
+					IEEE80211_EML_EMLSR_TRANS_DELAY);
+			if (trans_delay >
+			    IEEE80211_EML_CAP_EMLSR_TRANSITION_DELAY_256US)
+				return;
+
+			/* Update sta padding and transition delay */
+			sta->sta.eml_cap =
+				u8_replace_bits(sta->sta.eml_cap,
+						pad_delay,
+						IEEE80211_EML_CAP_EMLSR_PADDING_DELAY);
+			sta->sta.eml_cap =
+				u8_replace_bits(sta->sta.eml_cap,
+						trans_delay,
+						IEEE80211_EML_CAP_EMLSR_TRANSITION_DELAY);
+		}
+	}
+
+	if (control & IEEE80211_EML_CTRL_EMLMR_MODE) {
+		u8 mcs_map_size;
+		int i;
+
+		if (!(ift_ext_capa->eml_capabilities &
+		      IEEE80211_EML_CAP_EMLMR_SUPPORT))
+			return;
+
+		opt_len += sizeof(__le16); /* eMLMR link_bitmap */
+		opt_len++; /* eMLMR mcs_map_count */
+		if (skb->len < len + opt_len)
+			return;
+
+		eml_params.emlmr_mcs_map_count = ptr[2];
+		if (eml_params.emlmr_mcs_map_count > 2)
+			return;
+
+		mcs_map_size = 3 * (1 + eml_params.emlmr_mcs_map_count);
+		opt_len += mcs_map_size;
+		if (skb->len < len + opt_len)
+			return;
+
+		for (i = 0; i < mcs_map_size; i++) {
+			u8 rx_mcs, tx_mcs;
+
+			rx_mcs = u8_get_bits(ptr[3 + i],
+					     IEEE80211_EML_EMLMR_RX_MCS_MAP);
+			if (rx_mcs > 8)
+				return;
+
+			tx_mcs = u8_get_bits(ptr[3 + i],
+					     IEEE80211_EML_EMLMR_TX_MCS_MAP);
+			if (tx_mcs > 8)
+				return;
+		}
+
+		memcpy(eml_params.emlmr_mcs_map_bw, &ptr[3], mcs_map_size);
+	}
+
+	if ((control & IEEE80211_EML_CTRL_EMLSR_MODE) ||
+	    (control & IEEE80211_EML_CTRL_EMLMR_MODE)) {
+		eml_params.link_bitmap = get_unaligned_le16(ptr);
+		if ((eml_params.link_bitmap & sdata->vif.active_links) !=
+		    eml_params.link_bitmap)
+			return;
+	}
+
+	if (drv_set_eml_op_mode(sdata, &sta->sta, &eml_params))
+		return;
+
+	ieee80211_send_eml_op_mode_notif(sdata, mgmt, opt_len);
 }

net/mac80211/ieee80211_i.h

···
 
 u8 ieee80211_ie_len_eht_cap(struct ieee80211_sub_if_data *sdata);
 
+void ieee80211_rx_eml_op_mode_notif(struct ieee80211_sub_if_data *sdata,
+				    struct sk_buff *skb);
 void
 ieee80211_eht_cap_ie_to_sta_eht_cap(struct ieee80211_sub_if_data *sdata,
 				    struct ieee80211_supported_band *sband,

net/mac80211/iface.c

···
 		}
 	} else if (ieee80211_is_action(mgmt->frame_control) &&
 		   mgmt->u.action.category == WLAN_CATEGORY_PROTECTED_EHT) {
-		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+		if (sdata->vif.type == NL80211_IFTYPE_AP) {
+			switch (mgmt->u.action.u.eml_omn.action_code) {
+			case WLAN_PROTECTED_EHT_ACTION_EML_OP_MODE_NOTIF:
+				ieee80211_rx_eml_op_mode_notif(sdata, skb);
+				break;
+			default:
+				break;
+			}
+		} else if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 			switch (mgmt->u.action.u.ttlm_req.action_code) {
 			case WLAN_PROTECTED_EHT_ACTION_TTLM_REQ:
 				ieee80211_process_neg_ttlm_req(sdata, mgmt,

net/mac80211/rx.c

···
 					      u.action.u.epcs))
 				goto invalid;
 			goto queue;
+		case WLAN_PROTECTED_EHT_ACTION_EML_OP_MODE_NOTIF:
+			if (sdata->vif.type != NL80211_IFTYPE_AP)
+				break;
+
+			if (len < offsetofend(typeof(*mgmt),
+					      u.action.u.eml_omn))
+				goto invalid;
+			goto queue;
 		default:
 			break;
 		}

net/mac80211/trace.h

···
 	)
 );
 
+TRACE_EVENT(drv_set_eml_op_mode,
+	    TP_PROTO(struct ieee80211_local *local,
+		     struct ieee80211_sub_if_data *sdata,
+		     struct ieee80211_sta *sta,
+		     unsigned int link_id,
+		     u8 control, u16 link_bitmap),
+
+	TP_ARGS(local, sdata, sta, link_id, control, link_bitmap),
+
+	TP_STRUCT__entry(LOCAL_ENTRY
+			 VIF_ENTRY
+			 STA_ENTRY
+			 __field(u32, link_id)
+			 __field(u8, control)
+			 __field(u16, link_bitmap)),
+
+	TP_fast_assign(LOCAL_ASSIGN;
+		       VIF_ASSIGN;
+		       STA_NAMED_ASSIGN(sta);
+		       __entry->link_id = link_id;
+		       __entry->control = control;
+		       __entry->link_bitmap = link_bitmap;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT  VIF_PR_FMT  STA_PR_FMT
+		" (link:%d control:%02x link_bitmap:%04x)",
+		LOCAL_PR_ARG, VIF_PR_ARG, STA_PR_ARG, __entry->link_id,
+		__entry->control, __entry->link_bitmap
+	)
+);
+
 #endif /* !__MAC80211_DRIVER_TRACE || TRACE_HEADER_MULTI_READ */
 
 #undef TRACE_INCLUDE_PATH