Module: StructFu

Included in:
PacketFu::ARPHeader, PacketFu::AddrIpv6, PacketFu::EthHeader, PacketFu::HSRPHeader, PacketFu::ICMPHeader, PacketFu::IPHeader, PacketFu::IPv6Header, PacketFu::InvalidHeader, PacketFu::Octets, PacketFu::PcapFile, PacketFu::PcapHeader, PacketFu::PcapPacket, PacketFu::PcapPackets, PacketFu::TCPHeader, PacketFu::TcpEcn, PacketFu::TcpFlags, PacketFu::TcpHlen, PacketFu::TcpOption, PacketFu::TcpOptions, PacketFu::TcpReserved, PacketFu::Timestamp, PacketFu::UDPHeader
Defined in:
lib/packetfu/structfu.rb,
lib/packetfu/pcap.rb

Overview

StructFu, a nifty way to leverage Ruby’s built in Struct class to create meaningful binary data.

Defined Under Namespace

Classes: Int, Int16, Int16be, Int16le, Int32, Int32be, Int32le, Int8, IntString, String

Instance Method Summary collapse

Instance Method Details

#body=(i) ⇒ Object

Used like typecast(), but specifically for casting Strings to StructFu::Strings.



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# File 'lib/packetfu/structfu.rb', line 24

def body=(i)
	if i.kind_of? ::String
		typecast(i)
	elsif i.kind_of? StructFu
		self[:body] = i
	elsif i.nil?
		self[:body] = StructFu::String.new.read("")
	else
		raise ArgumentError, "Can't cram a #{i.class} into a StructFu :body"
	end
end

#clone ⇒ Object

Handle deep copies correctly. Marshal in 1.9, re-read myself on 1.8



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# File 'lib/packetfu/structfu.rb', line 37

def clone
	begin
		Marshal.load(Marshal.dump(self))
	rescue
		self.class.new.read(self.to_s)
	end
end

#set_endianness(e = nil) ⇒ Object

Set the endianness for the various Int classes. Takes either :little or :big.



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# File 'lib/packetfu/pcap.rb', line 6

def set_endianness(e=nil)
	unless [:little, :big].include? e
		raise ArgumentError, "Unknown endianness for #{self.class}" 
	end
	@int32 = e == :little ? Int32le : Int32be
	@int16 = e == :little ? Int16le : Int16be
	return e
end

#sz ⇒ Object Also known as: len

Normally, self.size and self.length will refer to the Struct size as an array. It’s a hassle to redefine, so this introduces some shorthand to get at the size of the resultant string.



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# File 'lib/packetfu/pcap.rb', line 18

def sz
	self.to_s.size
end

#typecast(i) ⇒ Object

Typecast is used mostly by packet header classes, such as IPHeader, TCPHeader, and the like. It takes an argument, and casts it to the expected type for that element.



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# File 'lib/packetfu/structfu.rb', line 18

def typecast(i)
	c = caller[0].match(/.*`([^']+)='/)[1]
	self[c.intern].read i
end