# coding: utf-8
# This file is part of PacketGen
# See https://github.com/sdaubert/packetgen for more informations
# Copyright (C) 2016 Sylvain Daubert <sylvain.daubert@laposte.net>
# This program is published under MIT license.

# frozen_string_literal: true

module PacketGen
  module Header
    class IKE

      # This class handles Identification - Initiator payloads, denoted IDi
      # (see RFC 7296, §3.5).
      #
      # A ID payload consists of the IKE generic payload header (see {Payload})
      # and some specific fields:
      #                        1                   2                   3
      #    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      #   | Next Payload  |C|  RESERVED   |         Payload Length        |
      #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      #   |   ID Type     |                 RESERVED                      |
      #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      #   |                                                               |
      #   ~                   Identification Data                         ~
      #   |                                                               |
      #   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      # These specific fields are:
      # * {#type} (ID type),
      # * {#reserved},
      # * and {#content} (Identification Data).
      #
      # == Create a IDi payload
      #   # Create a IKE packet with a IDi payload
      #   pkt = PacketGen.gen('IP').add('UDP').add('IKE').add('IKE::IDi', type: 'FQDN')
      #   pkt.ike_idi.content.read 'fqdn.example.org'
      #   pkt.calc_length
      # @author Sylvain Daubert
      class IDi < Payload

        # Payload type number
        PAYLOAD_TYPE = 35

        TYPES = {
          'IPV4_ADDR'   => 1,
          'FQDN'        => 2,
          'RFC822_ADDR' => 3,
          'IPV6_ADDR'   => 5,
          'DER_ASN1_DN' => 9,
          'DER_ASN1_GN' => 10,
          'KEY_ID'      => 11
        }

        # @attribute [r] type
        #   8-bit ID type
        #   @return [Integer]
        define_field_before :content, :type, Types::Int8Enum, enum: TYPES
        # @attribute reserved
        #   24-bit reserved field
        #   @return [Integer]
        define_field_before :content, :reserved, Types::Int24

        # Get ID type name
        # @return [String]
        def human_type
          self[:type].to_human
        end

        # Get human readable content, from {#type}
        # @return [String]
        def human_content
          case type
          when TYPES['IPV4_ADDR'], TYPES['IPV4_ADDR']
            IPAddr.ntop(content)
          when TYPES['DER_ASN1_DN'], TYPES['DER_ASN1_GN']
            OpenSSL::X509::Name.new(content).to_s
          else
            content.inspect
          end
        end
      end

      # This class handles Identification - Responder payloads, denoted IDr.
      # See {IDi}.
      #
      # == Create a IDr payload
      #   # Create a IKE packet with a IDr payload
      #   pkt = PacketGen.gen('IP').add('UDP').add('IKE').add('IKE::IDr', type: 'FQDN')
      #   pkt.ike_idr.content.read 'fqdn.example.org'
      # @author Sylvain Daubert
      class IDr < IDi
        # Payload type number
        PAYLOAD_TYPE = 36
      end
    end

    self.add_class IKE::IDi
    self.add_class IKE::IDr
  end
end