wifi: mac80211: provide a helper to fetch the medium synchronization delay

There are drivers which need this information.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230604120651.b1043f3126e2.Iad3806f8bf8df07f52ef0a02cc3d0373c44a8c93@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index fba4c44da832..516cd32d6196 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -4636,6 +4636,41 @@ static inline u8 ieee80211_mle_common_size(const u8 *data)
 }
 
 /**
+ * ieee80211_mle_get_eml_sync_delay - returns the medium sync delay
+ * @data: pointer to the multi link EHT IE
+ *
+ * The element is assumed to be big enough. This must be checked by
+ * ieee80211_mle_size_ok().
+ * If the medium synchronization can't be found (the type is not basic, or
+ * the medium sync presence bit is clear), 0 will be returned.
+ */
+static inline u16 ieee80211_mle_get_eml_med_sync_delay(const u8 *data)
+{
+	const struct ieee80211_multi_link_elem *mle = (const void *)data;
+	u16 control = le16_to_cpu(mle->control);
+	const u8 *common = mle->variable;
+
+	if (u16_get_bits(control, IEEE80211_ML_CONTROL_TYPE) !=
+	    IEEE80211_ML_CONTROL_TYPE_BASIC)
+		return 0;
+
+	/* common points now at the beginning of
+	 * ieee80211_mle_basic_common_info
+	 */
+	common += sizeof(struct ieee80211_mle_basic_common_info);
+
+	if (!(control & IEEE80211_MLC_BASIC_PRES_MED_SYNC_DELAY))
+		return 0;
+
+	if (control & IEEE80211_MLC_BASIC_PRES_LINK_ID)
+		common += 1;
+	if (control & IEEE80211_MLC_BASIC_PRES_BSS_PARAM_CH_CNT)
+		common += 1;
+
+	return get_unaligned_le16(common);
+}
+
+/**
  * ieee80211_mle_get_eml_cap - returns the EML capability
  * @data: pointer to the multi link EHT IE
  *