81 lines
2 KiB
Ruby
81 lines
2 KiB
Ruby
require 'huffman_tw'
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# Class holding the parsed packet data
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class Packet
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attr_reader :flags, :payload
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def initialize(data, prefix = '')
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# @data and @payload
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# are strings representing the raw bytes
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#
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# @prefix is a String that will be displayed
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# when printing the packet
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# use '>' and '<' for example to indicate
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# network direction (client/server)
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@prefix = prefix
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@huffman = Huffman.new
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@flags = {}
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@data = data
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flags_byte = @data[0].unpack("B*")
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parse_flags(flags_byte.first[2..5])
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@payload = @data[PACKET_HEADER_SIZE..]
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if flags_compressed
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@payload = @huffman.decompress(@payload.unpack("C*"))
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@payload = @payload.pack("C*")
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end
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end
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def annotate_first_row(bytes)
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header = bytes[0..2].join(' ').yellow
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token = bytes[3..6].join(' ').green
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payload = bytes[7..].join(' ')
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puts @prefix + " data: #{[header, token, payload].join(' ')}"
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print @prefix + " "
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print "header".ljust(3 * 3, ' ').yellow
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print "token".ljust(4 * 3, ' ').green
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puts "data"
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end
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def to_s()
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puts @prefix + "Packet"
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puts @prefix + " flags: #{@flags}"
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bytes = str_hex(@data).split(' ')
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# todo: check terminal size?
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max_width = 14
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rows = bytes.groups_of(max_width)
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annotate_first_row(rows.first)
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rows[1..].each do |row|
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print @prefix + " "
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puts row.join(' ')
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end
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puts ""
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end
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def parse_flags(four_bit_str)
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# takes a 4 character string
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# representing the middle of the first byte sent
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# in binary representation
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#
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# and creates a hash out of it
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@flags = {}
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@flags[:connection] = four_bit_str[0] == '1'
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@flags[:compressed] = four_bit_str[1] == '1'
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@flags[:resend] = four_bit_str[2] == '1'
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@flags[:control] = four_bit_str[3] == '1'
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@flags
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end
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def flags_compressed()
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@flags[:compressed]
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end
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def flags_connless()
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@flags[:connection] == false
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end
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def flags_control()
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@flags[:control]
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end
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end
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