Add NiciraStackPop

Rakefile

@@ -1,7 +1,7 @@
 require 'bundler/gem_tasks'
 
 RELISH_PROJECT = 'trema/pio'
-FLAY_THRESHOLD = 1204
+FLAY_THRESHOLD = 1410
 
 task default: :travis
 task test: [:spec, :cucumber]

features/open_flow13/nicira_stack_pop.feature

@@ -0,0 +1,28 @@
+@open_flow13
+Feature: Pio::NiciraStackPop
+
+  Pops field[offset: offset + n_bits] from top of the stack.
+
+  Scenario: new(:reg0)
+    When I try to create an OpenFlow action with:
+      """
+      Pio::NiciraStackPop.new(:reg0)
+      """
+    Then it should finish successfully
+    And the action has the following fields and values:
+      | field  | value |
+      | offset |     0 |
+      | n_bits |    32 |
+      | field  | :reg0 |
+
+  Scenario: new(:reg0, n_bits: 16, offset: 16)
+    When I try to create an OpenFlow action with:
+      """
+      Pio::NiciraStackPop.new(:reg0, n_bits: 16, offset: 16)
+      """
+    Then it should finish successfully
+    And the action has the following fields and values:
+      | field  | value |
+      | offset |    16 |
+      | n_bits |    16 |
+      | field  | :reg0 |

lib/pio/open_flow.rb

@@ -14,18 +14,21 @@ def self.version
       @version
     end
 
+    # rubocop:disable MethodLength
     def self.switch_version(version)
       [:Barrier, :Echo, :Features, :FlowMod, :Hello, :Match,
        :PacketIn, :FlowRemoved, :PacketOut, :SendOutPort,
        :SetSourceMacAddress, :SetDestinationMacAddress, :PortStatus, :Stats,
        :FlowStats, :DescriptionStats, :AggregateStats, :TableStats, :PortStats,
        :QueueStats, :Error, :SetArpOperation, :SetArpSenderProtocolAddress,
        :SetArpSenderHardwareAddress, :NiciraRegMove, :SetMetadata,
-       :NiciraRegLoad, :NiciraSendOutPort, :NiciraStackPush].each do |each|
+       :NiciraRegLoad, :NiciraSendOutPort, :NiciraStackPush,
+       :NiciraStackPop].each do |each|
         set_message_class_name each, version
         @version = version.to_s
       end
     end
+    # rubocop:enable MethodLength
 
     # rubocop:disable MethodLength
     def self.read(binary)

lib/pio/open_flow13.rb

@@ -18,6 +18,7 @@
 require 'pio/open_flow13/nicira_reg_load'
 require 'pio/open_flow13/nicira_reg_move'
 require 'pio/open_flow13/nicira_send_out_port'
+require 'pio/open_flow13/nicira_stack_pop'
 require 'pio/open_flow13/nicira_stack_push'
 require 'pio/open_flow13/send_out_port'
 require 'pio/open_flow13/set_arp_operation'

lib/pio/open_flow13/nicira_stack_pop.rb

@@ -0,0 +1,49 @@
+require 'pio/open_flow/nicira_action'
+require 'pio/open_flow13/match'
+
+module Pio
+  module OpenFlow13
+    # NXAST_STACK_POP action
+    class NiciraStackPop < OpenFlow::NiciraAction
+      nicira_action_header action_type: 0xffff,
+                           action_length: 24,
+                           subtype: 28
+      uint16 :_offset
+      struct :field do
+        uint16 :oxm_class
+        bit7 :oxm_field
+        bit1 :oxm_hasmask, value: 0
+        uint8 :oxm_length
+      end
+      uint16 :_n_bits
+      string :padding, length: 6
+      hide :padding
+
+      def initialize(field, options = {})
+        @field = field
+        super(_offset: options[:offset] || 0,
+              _n_bits: (options[:n_bits] || oxm_length * 8) + 1,
+              field: { oxm_class: field_oxm_class.const_get(:OXM_CLASS),
+                       oxm_field: field_oxm_class.const_get(:OXM_FIELD),
+                       oxm_length: oxm_length })
+      end
+
+      attr_reader :field
+      alias_method :offset, :_offset
+
+      def n_bits
+        _n_bits - 1
+      end
+
+      private
+
+      def oxm_length
+        field_oxm_class.new.length
+      end
+
+      def field_oxm_class
+        Match.const_get(@field.to_s.split('_').map(&:capitalize).join)
+      end
+    end
+  end
+end