Packet.IpSourceIPv4 frame of a packet.
The type tp represents packets at the transport protocol level, which are encapsulated within the IPv4 payload. At present, we only support TCP, UDP, ICMP and IGMP explicitly; otherwise, the raw bytes and IPv4 protocol number are provided.
type t = {tos : nwTos;Type of service.
*)ident : int16;Identification.
*)flags : Flags.t;IPv4 header flags.
*)frag : int16;Fragment offset.
*)ttl : int8;Time to live.
*)chksum : int16;Header checksum.
*)src : nwAddr;IP source address.
*)dst : nwAddr;IP destination address.
*)options : Cstruct.t;Uninterpreted IP options.
*)tp : tp;Transport payload.
*)}