struct udp { /* user dgram proto leader (fits over ip hdr) */ char u_x[8]; /* unused fields from ip */ u_char u_x1; /* unused */ u_char u_pr; /* protocol number */ u_short u_ilen; /* pseudo header length == UDP length */ struct socket u_s; /* source internet address */ struct socket u_d; /* destination internet address */ u_short u_src; /* source port */ u_short u_dst; /* destination port */ u_short u_len; /* length */ u_short u_sum; /* checksum */ }; #define UDPROTO 17 #define UDPSIZE 8 /* UDP header only */ #define UDPCKSIZE 12 /* UDP pseudo header */