I am getting weird issues with a struct. The struct is the IPv4
header. All but the last item(destination address) gives the correct
data(after some endian manipulation.

class IP4_header < FFI::Struct
    layout :eth_offset, :uchar,
14],:version,:uchar,:tos,:uchar,:len,:ushort,:id,:ushort,:frag_offset,:ushort,:ttl,:uchar,:proto,:uchar,
	:checksum,:ushort,:src_addr,:uint,:dest_addr,:uint
    IP_RF=8
    IP_DF=4
    IP_MF=2
    OFFMASK='ff1f'.to_i 16
  end

The first field eth_offset is just to get past the ethernet header,
probably the wrong way to do that.

src_addr returns 2831155968, which is the hex value A8C00300 which is
correct, after an endian adjustment: 192.168.0.3. The actual value
before the adjustment is 168.192.3.0.

dest_addr returns 3636658432 which is the hex value D8C30100 which is
completely incorrect. The next 4 bytes were expected to be read, but
the two bytes right after src_addr were skipped. If that is not bad
enough it is being read incorrectly. The returned value corresponds to
216.195.1.0.

The bytes, according to wireshark, right after src_addr is: C0 A8 00
01 C3 D8.

The first 4 bytes is the dest_addr and the last two are the first two
bytes in the UDP header. So dest_addr is skipping two bytes AND
reading it incorrectly. Given if it just skipped the two bytes, the
read bytes should be 01 00 d8 c3.