Merge ece8cae into 5e139a8

features/.nav

@@ -6,6 +6,7 @@
 - dhcp.feature
 - udp.feature
 - ethernet_header.feature
+- ipv4_header.feature
 - open_flow10:
   - hello.feature
   - hello_failed.feature

features/ipv4_header.feature

@@ -0,0 +1,78 @@
+Feature: IPv4Header
+  Scenario: create an IPv4 header
+    When I create a packet with:
+      """ruby
+      IPv4Header.new(source_ip_address: '1.2.3.4',
+                     destination_ip_address: '4.3.2.1')
+      """
+    Then the packet has the following fields and values:
+      | field                  |           value |
+      | class                  | Pio::IPv4Header |
+      | ip_version             |               4 |
+      | ip_header_length       |               5 |
+      | ip_type_of_service     |               0 |
+      | ip_total_length        |              20 |
+      | ip_identifier          |               0 |
+      | ip_flag                |               0 |
+      | ip_fragment            |               0 |
+      | ip_ttl                 |             128 |
+      | ip_protocol            |               0 |
+      | ip_header_checksum     |           12513 |
+      | source_ip_address      |         1.2.3.4 |
+      | destination_ip_address |         4.3.2.1 |
+      | ip_option              |                 |
+
+  Scenario: read an IPv4 header
+    Given I use the fixture "ipv4_header"
+    When I create a packet with:
+      """ruby
+      Pio::IPv4Header.read(eval(IO.read('ipv4_header.rb')))
+      """
+    Then the packet has the following fields and values:
+      | field                  |           value |
+      | class                  | Pio::IPv4Header |
+      | ip_version             |               4 |
+      | ip_header_length       |               5 |
+      | ip_type_of_service     |               0 |
+      | ip_total_length        |              20 |
+      | ip_identifier          |               0 |
+      | ip_flag                |               0 |
+      | ip_fragment            |               0 |
+      | ip_ttl                 |             128 |
+      | ip_protocol            |               0 |
+      | ip_header_checksum     |           12513 |
+      | source_ip_address      |         1.2.3.4 |
+      | destination_ip_address |         4.3.2.1 |
+      | ip_option              |                 |
+
+  Scenario: convert IPv4 header to Ruby code
+    When I eval the following Ruby code:
+      """ruby
+      IPv4Header.new(source_ip_address: '1.2.3.4',
+                     destination_ip_address: '4.3.2.1').to_ruby
+      """
+    Then the result of eval should be:
+      """ruby
+      [
+        0b0100_0101, # ip_version, ip_header_length
+        0x00, # ip_type_of_service
+        0x00, 0x14, # ip_total_length
+        0x00, 0x00, # ip_identifier
+        0b000_0000000000000, # ip_flag, ip_fragment
+        0x80, # ip_ttl
+        0x00, # ip_protocol
+        0x30, 0xe1, # ip_header_checksum
+        0x01, 0x02, 0x03, 0x04, # source_ip_address
+        0x04, 0x03, 0x02, 0x01, # destination_ip_address
+      ].pack('C6nC12')
+      """
+
+  Scenario: IPv4Header class inspection
+    When I eval the following Ruby code:
+      """ruby
+      Pio::IPv4Header.inspect
+      """
+    Then the result of eval should be:
+      """
+      IPv4Header(ip_version: bit4, ip_header_length: bit4, ip_type_of_service: uint8, ip_total_length: uint16, ip_identifier: uint16, ip_flag: bit3, ip_fragment: bit13, ip_ttl: uint8, ip_protocol: uint8, ip_header_checksum: uint16, source_ip_address: ip_address, destination_ip_address: ip_address, ip_option: string)
+      """

fixtures/ipv4_header/ipv4_header.rb

@@ -0,0 +1,12 @@
+[
+  0b0100_0101, # ip_version, ip_header_length
+  0x00, # ip_type_of_service
+  0x00, 0x14, # ip_total_length
+  0x00, 0x00, # ip_identifier
+  0b000_0000000000000, # ip_flag, ip_fragment
+  0x80, # ip_ttl
+  0x00, # ip_protocol
+  0x30, 0xe1, # ip_header_checksum
+  0x01, 0x02, 0x03, 0x04, # source_ip_address
+  0x04, 0x03, 0x02, 0x01, # destination_ip_address
+].pack('C6nC12')

lib/pio/dhcp/frame.rb

@@ -13,7 +13,7 @@ class Frame < BinData::Record
       OPTION_FIELD_LENGTH = 60
 
       include Ethernet
-      include IPv4Header
+      include IPv4
       include UdpHeader
 
       endian :big

lib/pio/icmp/format.rb

@@ -10,7 +10,7 @@ class Format < BinData::Record
       MINIMUM_IP_PACKET_LENGTH = 50
 
       include Ethernet
-      include IPv4Header
+      include IPv4
 
       endian :big
 

lib/pio/ipv4_header.rb

@@ -1,9 +1,11 @@
+require 'pio/monkey_patch/bindata_string'
 require 'pio/payload'
+require 'pio/ruby_dumper'
 require 'pio/type/ip_address'
 
 module Pio
   # IP Version 4 Header Format
-  module IPv4Header
+  module IPv4
     # Internet protocol numbers for ipv4_header.ip_protocol
     module ProtocolNumber
       ICMP = 1
@@ -82,4 +84,18 @@ def ip_option_length
       20 - ip_header_length * 4
     end
   end
+
+  # IPv4 header generator/parser
+  class IPv4Header < BinData::Record
+    include IPv4
+    include RubyDumper
+
+    ipv4_header
+
+    # rubocop:disable LineLength
+    def self.inspect
+      'IPv4Header(ip_version: bit4, ip_header_length: bit4, ip_type_of_service: uint8, ip_total_length: uint16, ip_identifier: uint16, ip_flag: bit3, ip_fragment: bit13, ip_ttl: uint8, ip_protocol: uint8, ip_header_checksum: uint16, source_ip_address: ip_address, destination_ip_address: ip_address, ip_option: string)'
+    end
+    # rubocop:enable LineLength
+  end
 end

lib/pio/monkey_patch/bindata_string.rb

@@ -0,0 +1,10 @@
+module BinData
+  # Add BinData::String#to_hex
+  class String
+    def to_hex
+      to_s.unpack('H*').pop.scan(/[0-9a-f]{2}/).map do |each|
+        "0x#{each}"
+      end.join(', ')
+    end
+  end
+end

lib/pio/parser.rb

@@ -17,7 +17,7 @@ class EthernetFrame < BinData::Record
     # IPv4 packet parser
     class IPv4Packet < BinData::Record
       include Ethernet
-      include IPv4Header
+      include IPv4
 
       endian :big
 

lib/pio/ruby_dumper.rb

@@ -13,10 +13,12 @@ def to_ruby
       bytes = ''
       bit = false
       bit_names = []
+      total_bit_length = 0
       field_names.each do |each|
         next unless __send__("#{each}?")
         if /Bit(\d+)$/ =~ __send__(each).class.to_s
-          bit_length = Regexp.last_match(1)
+          bit_length = Regexp.last_match(1).to_i
+          total_bit_length += bit_length
           if bit
             bit_names << each
             bytes << format("_%0#{bit_length}b", __send__(each))
@@ -28,11 +30,19 @@ def to_ruby
         else
           if bit
             bytes << ", # #{bit_names.join(', ')}\n"
-            pack_template << 'n'
+            if total_bit_length == 8
+              pack_template << 'C'
+            elsif total_bit_length == 16
+              pack_template << 'n'
+            else
+              raise
+            end
+            total_bit_length = 0
             bit_names = []
             bit = false
           end
           list = __send__(each).to_hex
+          next if list.empty?
           bytes << "  #{list}, # #{each}\n"
           pack_template << 'C' * (list.count(',') + 1)
         end

lib/pio/udp.rb

@@ -7,7 +7,7 @@ module Pio
   # UDP packet format
   class Udp < BinData::Record
     include Ethernet
-    include IPv4Header
+    include IPv4
     include UdpHeader
 
     endian :big

lib/pio/udp_header.rb

@@ -11,7 +11,7 @@ class PseudoUdpHeader < BinData::Record
       ip_address :source_ip_address
       ip_address :destination_ip_address
       uint8 :padding
-      uint8 :ip_protocol, value: IPv4Header::ProtocolNumber::UDP
+      uint8 :ip_protocol, value: IPv4::ProtocolNumber::UDP
       uint16 :udp_length
     end