ICMPHeader is a complete ICMP struct, used in ICMPPacket. ICMP is typically used for network administration and connectivity testing.

For more on ICMP packets, see www.networksorcery.com/enp/protocol/icmp.htm

Header Definition

  Int8    :icmp_type                        # Type
  Int8    :icmp_code                        # Code
  Int16   :icmp_sum    Default: calculated  # Checksum
  String  :body
Methods
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Included Modules
Class Public methods
new(args={})

Source: show 

# File lib/packetfu/protos/icmp.rb, line 19
                def initialize(args={})
                        super(
                                Int8.new(args[:icmp_type]),
                                Int8.new(args[:icmp_code]),
                                Int16.new(args[:icmp_sum] || icmp_calc_sum),
                                StructFu::String.new.read(args[:body])
                        )
                end
Instance Public methods
icmp_calc_sum()

Calculates and sets the checksum for the object.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 59
                def icmp_calc_sum
                        checksum = (icmp_type.to_i << 8)     + icmp_code.to_i
                        chk_body = (body.to_s.size % 2 == 0 ? body.to_s : body.to_s + "\x00")
                        if 1.respond_to? :ord
                                chk_body.scan(/../).map { |x| (x[0].ord << 8) + x[1].ord }.each { |y| checksum += y }
                        else
                                chk_body.scan(/../).map { |x| (x[0] << 8) + x[1] }.each { |y| checksum += y }
                        end
                        checksum = checksum % 0xffff
                        checksum = 0xffff - checksum
                        checksum == 0 ? 0xffff : checksum
                end
icmp_code()

Getter for the code.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 51
                def icmp_code; self[:icmp_code].to_i; end
icmp_code=(i)

Setter for the code.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 49
                def icmp_code=(i); typecast i; end
icmp_recalc(arg=:all)

Recalculates the calculatable fields for ICMP.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 73
                def icmp_recalc(arg=:all)
                        # How silly is this, you can't intern a symbol in ruby 1.8.7pl72?
                        # I'm this close to monkey patching Symbol so you can force it...
                        arg = arg.intern if arg.respond_to? :intern
                        case arg
                        when :icmp_sum
                                self.icmp_sum=icmp_calc_sum
                        when :all
                                self.icmp_sum=icmp_calc_sum
                        else
                                raise ArgumentError, "No such field `#{arg}'"
                        end
                end
icmp_sum()

Getter for the checksum.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 56
                def icmp_sum; self[:icmp_sum].to_i; end
icmp_sum=(i)

Setter for the checksum. Note, this is calculated automatically with icmp_calc_sum.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 54
                def icmp_sum=(i); typecast i; end
icmp_sum_readable()

Readability aliases

Source: show 

# File lib/packetfu/protos/icmp.rb, line 89
                def icmp_sum_readable
                        "0x%04x" % icmp_sum
                end
icmp_type()

Getter for the type.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 47
                def icmp_type; self[:icmp_type].to_i; end
icmp_type=(i)

Setter for the type.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 45
                def icmp_type=(i); typecast i; end
read(str)

Reads a string to populate the object.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 34
                def read(str)
                        force_binary(str)
                        return self if str.nil?
                        self[:icmp_type].read(str[0,1])
                        self[:icmp_code].read(str[1,1])
                        self[:icmp_sum].read(str[2,2])
                        self[:body].read(str[4,str.size])
                        self
                end
to_s()

Returns the object in string form.

Source: show 

# File lib/packetfu/protos/icmp.rb, line 29
                def to_s
                        self.to_a.map {|x| x.to_s}.join
                end