snack_missing
void snack_missing(connection_t *, ccb_t *, uint8_t, uint32_t, uint32_t);
snack_missing(conn, NULL, SNACK_STATUS_NAK,
snack_missing(req_ccb->ccb_connection, req_ccb,
snack_missing(conn, ccb, SNACK_DATA_NAK, 0, 0);
snack_missing(conn, NULL, SNACK_STATUS_NAK, 0, 0);