eap_hdr_validate() function

eap_hdr_validate - Validate EAP header @vendor: Expected EAP Vendor-Id (0 = IETF) @eap_type: Expected EAP type number @msg: EAP frame (starting with EAP header) @plen: Pointer to variable to contain the returned payload length Returns: Pointer to EAP payload (after type field), or %NULL on failure This is a helper function for EAP method implementations. This is usually called in the beginning of struct eap_method::process() function to verify that the received EAP request packet has a valid header. This function is able to process both legacy and expanded EAP headers and in most cases, the caller can just use the returned payload pointer (into *plen) for processing the payload regardless of whether the packet used the expanded EAP header or not.