boxofrad

package main

import (
	"fmt"
	"time"
)

type Video struct {
	Name string
}

boxofrad

require 'socket'

BUFFER_SIZE = 1024

socket = UDPSocket.new
socket.bind('192.168.33.10', 4321)

loop do
  message, sender = socket.recvfrom(BUFFER_SIZE)

boxofrad

socket = Socket.new(:INET, :DGRAM)

boxofrad

require 'socket'

# Size in bytes of a C `ifreq` structure on a 64-bit system
# http://man7.org/linux/man-pages/man7/netdevice.7.html 
#
# struct ifreq {
#     char ifr_name[IFNAMSIZ]; /* Interface name */
#     union {
#         struct sockaddr ifr_addr;
#         struct sockaddr ifr_dstaddr;

boxofrad

# Receive every packet
ETH_P_ALL = 0x0300

# Size in bytes of a C `sockaddr_ll` structure on a 64-bit system
#
# struct sockaddr_ll {
#     unsigned short sll_family;   /* Always AF_PACKET */
#     unsigned short sll_protocol; /* Physical-layer protocol */
#     int            sll_ifindex;  /* Interface number */
#     unsigned short sll_hatype;   /* ARP hardware type */

boxofrad

require 'hexdump'

BUFFER_SIZE = 1024

loop do
  data = socket.recv(BUFFER_SIZE)
  Hexdump.dump(data)
end

boxofrad

class EthernetFrame
  attr_reader :bytes

  def initialize(bytes)
    @bytes = bytes
  end

  def destination_mac
    format_mac(bytes[0, 6])
  end

boxofrad

def data
  # Drop the first 14 bytes (MAC Header) and last 4 bytes (CRC Checksum)
  IPPacket.new(bytes[14...-4])
end

boxofrad

class IPPacket
  attr_reader :bytes
  
  def initialize(bytes)
    @bytes = bytes
  end
  
  def version
    bytes[0] >> 4
  end

boxofrad

def ihl
  bytes[0] & 0xF
end