Using pcap_open_live

pcap_open_live_and_next.cr

@[Link("pcap")]
lib LibPcap
  # previous code ...
  
  type PcapT = Void*
  alias UChar = UInt8
  alias BpfUInt32 = LibC::UInt

  struct Timeval
    tv_sec  : LibC::Long
    tv_usec : LibC::Long
  end

  struct PcapPkthdr
    ts     : Timeval
    caplen : BpfUInt32
    len    : BpfUInt32
  end

  fun pcap_open_live(device : LibC::Char*, 
                    snaplen : LibC::Int, 
                    promisc : LibC::Int, 
                      to_ms : LibC::Int, 
                     errbuf : LibC::Char*) : PcapT
  
  fun pcap_next_ex(capture : PcapT, header : PcapPkthdr**, data : UChar**) : LibC::Int
end