NDS_GET_PDU
rc = NDS_GET_PDU(nds, 0, 8, (char *)hdr, 0, 0);
rc = NDS_GET_PDU(nds, 0, 8, (char *)hdr, 0, 0);
rc = NDS_GET_PDU(nds, pdu_offset, 4, (char *)sizing_p,
rc = NDS_GET_PDU(nds, ref->pdu_offset, size,