wifi: mac80211: parse all TTLM entries

For the follow up patch, we need to properly parse TTLM entries that do
not have a switch time. Change the logic so that ieee80211_parse_adv_t2l
returns usable values in all non-error cases. Before the values filled
in were technically incorrect but enough for ieee80211_process_adv_ttlm.

Signed-off-by: Benjamin Berg <[e-mail]>
Reviewed-by: Johannes Berg <[e-mail]>
Reviewed-by: Ilan Peer <[e-mail]>
Signed-off-by: Miri Korenblit <[e-mail]>
Link: https://patch.msgid.link/20260118093904.ccd324e2dd59.I69f0bee0a22e9b11bb95beef313e305dab17c051@changeid
Signed-off-by: Johannes Berg <[e-mail]>

net/mac80211/mlme.c

···
 	pos = (void *)ttlm->optional;
 	control	= ttlm->control;
 
-	if ((control & IEEE80211_TTLM_CONTROL_DEF_LINK_MAP) ||
-	    !(control & IEEE80211_TTLM_CONTROL_SWITCH_TIME_PRESENT))
-		return 0;
-
 	if ((control & IEEE80211_TTLM_CONTROL_DIRECTION) !=
 	    IEEE80211_TTLM_DIRECTION_BOTH) {
 		sdata_info(sdata, "Invalid advertised T2L map direction\n");
···
 	link_map_presence = *pos;
 	pos++;
 
-	ttlm_info->switch_time = get_unaligned_le16(pos);
+	if (control & IEEE80211_TTLM_CONTROL_SWITCH_TIME_PRESENT) {
+		ttlm_info->switch_time = get_unaligned_le16(pos);
 
-	/* Since ttlm_info->switch_time == 0 means no switch time, bump it
-	 * by 1.
-	 */
-	if (!ttlm_info->switch_time)
-		ttlm_info->switch_time = 1;
+		/* Since ttlm_info->switch_time == 0 means no switch time, bump
+		 * it by 1.
+		 */
+		if (!ttlm_info->switch_time)
+			ttlm_info->switch_time = 1;
 
-	pos += 2;
+		pos += 2;
+	}
 
 	if (control & IEEE80211_TTLM_CONTROL_EXPECTED_DUR_PRESENT) {
 		ttlm_info->duration = pos[0] | pos[1] << 8 | pos[2] << 16;
 		pos += 3;
+	}
+
+	if (control & IEEE80211_TTLM_CONTROL_DEF_LINK_MAP) {
+		ttlm_info->map = 0xffff;
+		return 0;
 	}
 
 	if (control & IEEE80211_TTLM_CONTROL_LINK_MAP_SIZE)