Class: Dot11::PacketSet

Inherits:
Object
  • Object
show all
Defined in:
lib/dot11/packetset.rb

Defined Under Namespace

Classes: Pair

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(klass, parameters) ⇒ PacketSet

Returns a new instance of PacketSet.



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# File 'lib/dot11/packetset.rb', line 8

def initialize(klass, parameters)
  @fields = []

  @packet_class = klass

  parameters.each_pair do |key, value|
    @fields << Pair.new(key, value)
  end
    
  @field_sizes = @fields.map do |field|
    if field.value.respond_to?(:size) && !(field.value.kind_of?(String) || field.value.kind_of?(Numeric))
      field.value.size
    elsif field.value.respond_to?(:entries)
      field.value.entries.size
    else
      field.value = [field.value]
      1
    end
  end
end

Instance Attribute Details

#fields ⇒ Object (readonly)

Returns the value of attribute fields.



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# File 'lib/dot11/packetset.rb', line 6

def fields
  @fields
end

#packet_class ⇒ Object

Returns the value of attribute packet_class.



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# File 'lib/dot11/packetset.rb', line 5

def packet_class
  @packet_class
end

Instance Method Details

#[](index) ⇒ Object 



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# File 'lib/dot11/packetset.rb', line 29

def [](index)          
  indices = @field_sizes.inject([]) do |accumulator, size|
    remainder = index % size 
    index /= size # yeah textmate isn't perfect and that's why I need this slash: /      
    accumulator << remainder
  end

  field_hash = {}

  indices.each_with_index do |index, i|  
    value = @fields[i].value
  
    if value.kind_of?(Array) or value.kind_of?(Range)
      field_hash[@fields[i].name] = @fields[i].value.entries[index]
    else
      field_hash[@fields[i].name] = @fields[i].value
    end      
  end

  out = @packet_class.new(field_hash)

  out
end

#bitrange_to_filter(offset, size, bitrange, desired, negated = false) ⇒ Object 



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# File 'lib/dot11/packetset.rb', line 78

def bitrange_to_filter(offset, size, bitrange, desired, negated = false)
  # TODO: Take bitrange.exclude_end? into account
  mask = ((2 << (bitrange.end - bitrange.begin)) - 1) << bitrange.begin
  
  value = "(ether[#{offset}:#{size}] & #{'%#x' % mask}) >> #{bitrange.begin}"
  
  case desired
  when Range
    "(#{value} >= #{'%#x' % desired.begin} && #{value} #{desired.exclude_end? ? "<" : "<="} #{'%#x' % desired.end})"
  when Array
    # TODO: deal with arrays of ranges
    '(' + desired.map {|d| "#{value} = #{'%#x' % d}"}.join(" || ") + ')'
  when Numeric, String
    "#{value} #{negated ? '!' : ''}= #{'%#x' % desired.to_i}"
  else
    raise "unknown"
  end
end

#decode_condition(fields, condition) ⇒ Object 



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# File 'lib/dot11/packetset.rb', line 145

def decode_condition(fields, condition)
  case condition
  when Array
    condition.map{|x| decode_condition(fields, x)}.join(" || ")
  when Hash
    condition.map do |key, value|
      # Decode the nasty negation syntax
      negated, value = value.kind_of?(Array) && value.size == 1 ? [true, value[0]] : [false, value]

      field_info = fields.find{|x| key == x[0]}[1]
      
      case field_info[:type]
      when :int
        if field_info.has_key?(:bitrange)
          bitrange_to_filter(field_info[:offset], field_info[:size], field_info[:bitrange], value, negated)
        else
          int_to_filter(field_info[:offset], field_info[:size], value, negated)
        end
      when :mac
        mac_to_filter(field_info[:offset], field_info[:size], value, negated)
      else
        raise "unknown"  
      end
    end.join(" && ")
  end
end

#each(prefix = []) ⇒ Object 



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# File 'lib/dot11/packetset.rb', line 57

def each(prefix = [])
  size.times do |i|
    yield self[i]
  end
end

#each_with_index ⇒ Object 



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# File 'lib/dot11/packetset.rb', line 63

def each_with_index
  size.times do |i|
    yield self[i], i
  end
end

#include?(packet) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dot11/packetset.rb', line 69

def include?(packet)
  # This is horrrrrribly inefficient. FIXME
  each do |pkt|
    return true if packet == pkt
  end

  false
end

#int_to_filter(offset, size, desired, negated = false) ⇒ Object 



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# File 'lib/dot11/packetset.rb', line 97

def int_to_filter(offset, size, desired, negated = false)
  value = "ether[#{offset}:#{size}]"
  
  case desired
  when Range
    "(#{value} >= #{'%#x' % desired.begin} && #{value} #{desired.exclude_end? ? "<" : "<="} #{'%#x' % desired.end})"
  when Array
    # TODO: deal with arrays of ranges
    desired.map {|d| "#{value} #{negated ? '!' : ''}= #{'%#x' % d}"}.join(" || ")
  when Numeric
    "#{value} #{negated ? '!' : ''}= #{'%#x' % desired}"
  else
    raise "unknown desired: #{desired.inspect}"  
  end      
end

#mac_to_filter(offset, size, desired, negated = false) ⇒ Object 



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# File 'lib/dot11/packetset.rb', line 113

def mac_to_filter(offset, size, desired, negated = false)      
  case desired
  when Range
    raise "Range of MAC addresses in filter not yet implemented"
  when Array
    '(' + desired.map do |d| 
      desired = MACAddress.new(desired) if desired.kind_of?(String)
      first_four = desired[0, 4].pack("CCCC").unpack("N")[0]
      second_two = desired[4, 2].pack("CC").unpack("n")[0]

      "(ether[#{offset}:2] = #{'%#x' % first_four} && ether[#{offset + 4}:2] = #{'%#x' % second_two})"
    end.join(" || ") + ')'
  when Numeric

  when MACAddress, String
    desired = MACAddress.new(desired) if desired.kind_of?(String)
    first_four = desired[0, 4].pack("CCCC").unpack("N")[0]
    second_two = desired[4, 2].pack("CC").unpack("n")[0]
    
    
    if desired.prefix_length == 32
      "ether[#{offset}:4] = #{'%#x' % first_four}"
    elsif desired.prefix_length == 48 || desired.prefix_length == 0
      "(ether[#{offset}:4] = #{'%#x' % first_four} && ether[#{offset + 4}:2] = #{'%#x' % second_two})"
    else
      raise "unsupport prefix length #{desired.prefix_length}"  
    end
  else
    raise "unknown"  
  end
end

#size ⇒ Object 



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# File 'lib/dot11/packetset.rb', line 53

def size
  @field_sizes.inject(1) { |product, size| size * product }
end

#to_filter ⇒ Object 



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# File 'lib/dot11/packetset.rb', line 172

def to_filter
  fields = @packet_class.fields

  @fields.map do |field|
    '(' + begin
      field_info = fields.find{|x| field.name == x[0]}
      
      if field_info.nil?
        raise "nil field_info"
      end
      
      field_info = field_info[1]
      
      # We don't really want to do this
      if field_info.nil?
        raise "nil field_info 2"
      end
            
      if field_info.has_key?(:condition)
        if !field_info[:offset].kind_of?(Numeric)
          field_info[:offset].map do |key, value|
            '(' + begin
              if key == :else
                field_info[:offset].keys.reject{|k| k == :else}.map do |k|
                  '!(' + decode_condition(fields, k) + ')'
                end.join(" && ")
              else
                '(' + decode_condition(fields, key) + ') && (' + begin
                  case field_info[:type]
                  when :int
                    if field_info.has_key?(:bitrange)
                      bitrange_to_filter(value, field_info[:size], field_info[:bitrange], field.value)
                    else
                      int_to_filter(value, field_info[:size], field.value)
                    end
                  when :mac
                    mac_to_filter(value, field_info[:size], field.value)
                  else
                    raise "unknown"  
                  end
                end
              end
            end + ')'
          end.join(" && ")
        else
          '((' + decode_condition(fields, field_info[:condition]) +') && ('+ case field_info[:type]
          when :int
            if field_info.has_key?(:bitrange)
              bitrange_to_filter(field_info[:offset], field_info[:size], field_info[:bitrange], field.value)
            else
              int_to_filter(field_info[:offset], field_info[:size], field.value)
            end
          when :mac
            mac_to_filter(field_info[:offset], field_info[:size], field.value)
          else
            raise "unknown"  
          end + '))'
        end
      else
        if !field_info[:offset].kind_of?(Numeric)
          p "moo"
          "can"
        else
          case field_info[:type]
          when :int
            if field_info.has_key?(:bitrange)
              bitrange_to_filter(field_info[:offset], field_info[:size], field_info[:bitrange], field.value)
            else
              int_to_filter(field_info[:offset], field_info[:size], field.value)
            end
          when :mac
            mac_to_filter(field_info[:offset], field_info[:size], field.value)
          else
            raise "unknown"  
          end
        end
      end
    end + ')'
  end.join(" && ")
end