This page hosts a formal specification of ICMP network packet using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Ruby generated by Kaitai Struct depends on the Ruby runtime library. You have to install it before you can parse data.
The Ruby runtime library can be installed from RubyGems:
gem install kaitai-struct
Parse a local file and get structure in memory:
data = IcmpPacket.from_file("path/to/local/file.bin")
Or parse structure from a string of bytes:
bytes = "\x00\x01\x02..."
data = IcmpPacket.new(Kaitai::Struct::Stream.new(bytes))
After that, one can get various attributes from the structure by invoking getter methods like:
data.icmp_type # => get icmp type
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
require 'kaitai/struct/struct'
unless Gem::Version.new(Kaitai::Struct::VERSION) >= Gem::Version.new('0.9')
raise "Incompatible Kaitai Struct Ruby API: 0.9 or later is required, but you have #{Kaitai::Struct::VERSION}"
end
class IcmpPacket < Kaitai::Struct::Struct
ICMP_TYPE_ENUM = {
0 => :icmp_type_enum_echo_reply,
3 => :icmp_type_enum_destination_unreachable,
4 => :icmp_type_enum_source_quench,
5 => :icmp_type_enum_redirect,
8 => :icmp_type_enum_echo,
11 => :icmp_type_enum_time_exceeded,
}
I__ICMP_TYPE_ENUM = ICMP_TYPE_ENUM.invert
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@icmp_type = Kaitai::Struct::Stream::resolve_enum(ICMP_TYPE_ENUM, @_io.read_u1)
if icmp_type == :icmp_type_enum_destination_unreachable
@destination_unreachable = DestinationUnreachableMsg.new(@_io, self, @_root)
end
if icmp_type == :icmp_type_enum_time_exceeded
@time_exceeded = TimeExceededMsg.new(@_io, self, @_root)
end
if ((icmp_type == :icmp_type_enum_echo) || (icmp_type == :icmp_type_enum_echo_reply))
@echo = EchoMsg.new(@_io, self, @_root)
end
self
end
class DestinationUnreachableMsg < Kaitai::Struct::Struct
DESTINATION_UNREACHABLE_CODE = {
0 => :destination_unreachable_code_net_unreachable,
1 => :destination_unreachable_code_host_unreachable,
2 => :destination_unreachable_code_protocol_unreachable,
3 => :destination_unreachable_code_port_unreachable,
4 => :destination_unreachable_code_fragmentation_needed_and_df_set,
5 => :destination_unreachable_code_source_route_failed,
6 => :destination_unreachable_code_dst_net_unkown,
7 => :destination_unreachable_code_sdt_host_unkown,
8 => :destination_unreachable_code_src_isolated,
9 => :destination_unreachable_code_net_prohibited_by_admin,
10 => :destination_unreachable_code_host_prohibited_by_admin,
11 => :destination_unreachable_code_net_unreachable_for_tos,
12 => :destination_unreachable_code_host_unreachable_for_tos,
13 => :destination_unreachable_code_communication_prohibited_by_admin,
14 => :destination_unreachable_code_host_precedence_violation,
15 => :destination_unreachable_code_precedence_cuttoff_in_effect,
}
I__DESTINATION_UNREACHABLE_CODE = DESTINATION_UNREACHABLE_CODE.invert
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@code = Kaitai::Struct::Stream::resolve_enum(DESTINATION_UNREACHABLE_CODE, @_io.read_u1)
@checksum = @_io.read_u2be
self
end
attr_reader :code
attr_reader :checksum
end
class TimeExceededMsg < Kaitai::Struct::Struct
TIME_EXCEEDED_CODE = {
0 => :time_exceeded_code_time_to_live_exceeded_in_transit,
1 => :time_exceeded_code_fragment_reassembly_time_exceeded,
}
I__TIME_EXCEEDED_CODE = TIME_EXCEEDED_CODE.invert
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@code = Kaitai::Struct::Stream::resolve_enum(TIME_EXCEEDED_CODE, @_io.read_u1)
@checksum = @_io.read_u2be
self
end
attr_reader :code
attr_reader :checksum
end
class EchoMsg < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@code = @_io.read_bytes(1)
raise Kaitai::Struct::ValidationNotEqualError.new([0].pack('C*'), code, _io, "/types/echo_msg/seq/0") if not code == [0].pack('C*')
@checksum = @_io.read_u2be
@identifier = @_io.read_u2be
@seq_num = @_io.read_u2be
@data = @_io.read_bytes_full
self
end
attr_reader :code
attr_reader :checksum
attr_reader :identifier
attr_reader :seq_num
attr_reader :data
end
attr_reader :icmp_type
attr_reader :destination_unreachable
attr_reader :time_exceeded
attr_reader :echo
end