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

As previously defined in the header file, this element has a
different layout depending on the action frame it's carried
in, so the 'type' is no longer sufficient. Add a new enum
indicating which 'action_frame' we're parsing to allow for
this, and parse the element accordingly in SMD Transition
preparation and execution responses, in preparation for ST
implementation.

Assisted-by: LLM
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/mac80211/ieee80211_i.h | 26 ++++++++++++++++++++++++++
 net/mac80211/parse.c       | 18 ++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index eb31691c89d5..7e6e87ccce08 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1916,6 +1916,8 @@ struct ieee802_11_elems {
 	const struct ieee80211_uhr_operation *uhr_operation;
 	const struct ieee80211_cip_cap *cip_cap;
 	const struct ieee80211_uhr_parameters_update *uhr_param_upd;
+	const struct ieee80211_smd_bss_trans_params_prep_resp *smd_prep_resp;
+	const struct ieee80211_smd_bss_trans_params_exec_resp *smd_exec_resp;
 
 	/* not the order in the psd values is per element, not per chandef */
 	struct ieee80211_parsed_tpe tpe;
@@ -2553,6 +2555,26 @@ static inline void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata,
 	ieee80211_tx_skb_tid(sdata, skb, NULL, 7, -1);
 }
 
+/**
+ * enum ieee80211_parse_action_frame - action frame context for element parsing
+ *
+ * Some elements reuse the same element ID for different structures depending
+ * on which action frame they appear in. This selects the action frame the
+ * elements came from so the parser can extract the correct variant.
+ *
+ * @IEEE80211_PARSE_ACTION_FRAME_UNSPECIFIED: not one of the action frames that
+ *	need such disambiguation - parse elements normally
+ * @IEEE80211_PARSE_ACTION_FRAME_ST_PREP_RESP: SMD transition preparation
+ *	response
+ * @IEEE80211_PARSE_ACTION_FRAME_ST_EXEC_RESP: SMD transition execution
+ *	response
+ */
+enum ieee80211_parse_action_frame {
+	IEEE80211_PARSE_ACTION_FRAME_UNSPECIFIED = 0,
+	IEEE80211_PARSE_ACTION_FRAME_ST_PREP_RESP,
+	IEEE80211_PARSE_ACTION_FRAME_ST_EXEC_RESP,
+};
+
 /**
  * struct ieee80211_elems_parse_params - element parsing parameters
  * @mode: connection mode for parsing
@@ -2572,6 +2594,9 @@ static inline void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata,
  *	(or re-association) response frame if this is given
  * @from_ap: frame is received from an AP (currently used only
  *	for EHT capabilities parsing)
+ * @action_frame: which action frame the elements came from, to
+ *	disambiguate elements that reuse the same element ID across different
+ *	action frames, or %IEEE80211_PARSE_ACTION_FRAME_UNSPECIFIED
  */
 struct ieee80211_elems_parse_params {
 	enum ieee80211_conn_mode mode;
@@ -2583,6 +2608,7 @@ struct ieee80211_elems_parse_params {
 	struct cfg80211_bss *bss;
 	int link_id;
 	bool from_ap;
+	enum ieee80211_parse_action_frame action_frame;
 };
 
 struct ieee802_11_elems *
diff --git a/net/mac80211/parse.c b/net/mac80211/parse.c
index 22bba5adef26..c392ecf58b0c 100644
--- a/net/mac80211/parse.c
+++ b/net/mac80211/parse.c
@@ -236,6 +236,20 @@ ieee80211_parse_extension_element(u32 *crc,
 		elems_parse->uhr_param_upd.start = params->start;
 		elems_parse->uhr_param_upd.len = params->len;
 		break;
+	case WLAN_EID_EXT_BSS_SMD_TRANS_PARAMS:
+		switch (params->action_frame) {
+		case IEEE80211_PARSE_ACTION_FRAME_ST_PREP_RESP:
+			if (ieee80211_smd_prep_resp_size_ok(data, len))
+				elems->smd_prep_resp = data;
+			break;
+		case IEEE80211_PARSE_ACTION_FRAME_ST_EXEC_RESP:
+			if (ieee80211_smd_exec_resp_size_ok(data, len))
+				elems->smd_exec_resp = data;
+			break;
+		default:
+			break;
+		}
+		break;
 	}
 
 	if (crc && calc_crc)
@@ -351,6 +365,10 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 		break;
 	}
 
+	WARN(params->type != (IEEE80211_FTYPE_MGMT | IEEE80211_STYPE_ACTION) &&
+	     params->action_frame != IEEE80211_PARSE_ACTION_FRAME_UNSPECIFIED,
+	     "action frame type specified for non-action frame\n");
+
 	for_each_element(elem, params->start, params->len) {
 		const struct element *subelem;
 		u8 elem_parse_failed;
-- 
2.56.0