wifi: mac80211: Support parsing EPCS ML element

Add support for parsing an ML element of type EPCS priority
access, which can optionally be included in EHT protected action
frames used to configure EPCS.

Signed-off-by: Ilan Peer <[email protected]>
Reviewed-by: Johannes Berg <[email protected]>
Signed-off-by: Miri Korenblit <[email protected]>
Link: https://patch.msgid.link/20250102161730.5afdf65cff46.I0ffa30b40fbad47bc5b608b5fd46047a8c44e904@changeid
Signed-off-by: Johannes Berg <[email protected]>

Author: ilanpeer2

net/mac80211/ieee80211_i.h

@@ -1762,6 +1762,7 @@ struct ieee802_11_elems {
 	const struct ieee80211_eht_operation *eht_operation;
 	const struct ieee80211_multi_link_elem *ml_basic;
 	const struct ieee80211_multi_link_elem *ml_reconf;
+	const struct ieee80211_multi_link_elem *ml_epcs;
 	const struct ieee80211_bandwidth_indication *bandwidth_indication;
 	const struct ieee80211_ttlm_elem *ttlm[IEEE80211_TTLM_MAX_CNT];
 
@@ -1792,6 +1793,7 @@ struct ieee802_11_elems {
 	/* mult-link element can be de-fragmented and thus u8 is not sufficient */
 	size_t ml_basic_len;
 	size_t ml_reconf_len;
+	size_t ml_epcs_len;
 
 	u8 ttlm_num;
 

net/mac80211/parse.c

@@ -44,6 +44,9 @@ struct ieee80211_elems_parse {
 	/* The reconfiguration Multi-Link element in the original elements */
 	const struct element *ml_reconf_elem;
 
+	/* The EPCS Multi-Link element in the original elements */
+	const struct element *ml_epcs_elem;
+
 	/*
 	 * scratch buffer that can be used for various element parsing related
 	 * tasks, e.g., element de-fragmentation etc.
@@ -159,6 +162,9 @@ ieee80211_parse_extension_element(u32 *crc,
 			case IEEE80211_ML_CONTROL_TYPE_RECONF:
 				elems_parse->ml_reconf_elem = elem;
 				break;
+			case IEEE80211_ML_CONTROL_TYPE_PRIO_ACCESS:
+				elems_parse->ml_epcs_elem = elem;
+				break;
 			default:
 				break;
 			}
@@ -943,6 +949,27 @@ ieee80211_mle_defrag_reconf(struct ieee80211_elems_parse *elems_parse)
 	elems_parse->scratch_pos += ml_len;
 }
 
+static void
+ieee80211_mle_defrag_epcs(struct ieee80211_elems_parse *elems_parse)
+{
+	struct ieee802_11_elems *elems = &elems_parse->elems;
+	ssize_t ml_len;
+
+	ml_len = cfg80211_defragment_element(elems_parse->ml_epcs_elem,
+					     elems->ie_start,
+					     elems->total_len,
+					     elems_parse->scratch_pos,
+					     elems_parse->scratch +
+						elems_parse->scratch_len -
+						elems_parse->scratch_pos,
+					     WLAN_EID_FRAGMENT);
+	if (ml_len < 0)
+		return;
+	elems->ml_epcs = (void *)elems_parse->scratch_pos;
+	elems->ml_epcs_len = ml_len;
+	elems_parse->scratch_pos += ml_len;
+}
+
 struct ieee802_11_elems *
 ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params)
 {
@@ -1001,6 +1028,8 @@ ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params)
 
 	ieee80211_mle_defrag_reconf(elems_parse);
 
+	ieee80211_mle_defrag_epcs(elems_parse);
+
 	if (elems->tim && !elems->parse_error) {
 		const struct ieee80211_tim_ie *tim_ie = elems->tim;