*/
dev->needed_tailroom = IEEE802154_MAX_AUTH_TAG_LEN +
IEEE802154_FCS_LEN;
- dev->mtu = IEEE802154_MTU;
+ /* The mtu size is the payload without mac header in this case.
+ * We have a dynamic length header with a minimum header length
+ * which is hard_header_len. In this case we let mtu to the size
+ * of maximum payload which is IEEE802154_MTU - IEEE802154_FCS_LEN -
+ * hard_header_len. The FCS which is set by hardware or ndo_start_xmit
+ * and the minimum mac header which can be evaluated inside driver
+ * layer. The rest of mac header will be part of payload if greater
+ * than hard_header_len.
+ */
+ dev->mtu = IEEE802154_MTU - IEEE802154_FCS_LEN -
+ dev->hard_header_len;
dev->tx_queue_len = 300;
dev->flags = IFF_NOARP | IFF_BROADCAST;
}