constructing and parsing network packet

I have the following packet format: 1B 4B 1B 1B string 2 bytes 1B string +------+----------+---+--------+---~~--+---------+--------+---~~---+ | type | lifetime | 2 | length | Name | Counter | length | Data | +------+----------+---+--------+---~~--+---------+--------+---~~---+ typedef struct pkt_data { u_char pkt_type; u_int lifetime; u_char type;