TCP Header (Bytefield)
(defattrs :src-port {:fill "#a0ffa0"})
(defattrs :dst-port {:fill "#ffffa0"})
(defattrs :seq {:fill "#a0fafa"})
(defattrs :flags {:fill "#ffb0a0"})
(draw-column-headers)
(draw-box "Source Port" [:src-port {:span 2}])
(draw-box "Dest Port" [:dst-port {:span 2}])
(draw-box "Sequence" [:seq {:span 4}])
(draw-box "Ack Number" [:seq {:span 4}])
(draw-box "Offset" {:span 1})
(draw-box "Flags" [:flags {:span 1}])
(draw-box "Window" {:span 2})
(draw-box "Checksum" {:span 2})
(draw-box "Urgent" {:span 2})
(draw-bottom)