tlv_header_t
const struct tlv_header_t *tlv_header;
TCHECK2(*tptr, sizeof(struct tlv_header_t));
tlv_header = (const struct tlv_header_t *)tptr;
if (tlv_len < sizeof(struct tlv_header_t) || tlv_len > tlen) {
tlv_tptr = tptr + sizeof(struct tlv_header_t);
tlv_tlen = tlv_len - sizeof(struct tlv_header_t);