UDP header

The macro UDP_HDR builds a UDP header, as defined in [RFC768]. The macro UDP_PCK prepends an IPv4 header to the UDP header.

$$\begin{tabular}{\vert cccccccccccccccccccccccccccccccc\vert}... ...rt}{0} & \multicolumn{16}{c\vert}{0} \\ \hline \end{tabular}$$

Example:

$udp_sport=53   /* DNS */

send UDP_PCK($ip_src=198.41.0.4 $udp_sport=5432)