data.rb in packetgen-2.7.0

- old
+ new

@@ -7,11 +7,10 @@
 # frozen_string_literal: true
 
 module PacketGen
   module Header
     class Dot11
-
       # IEEE 802.11 data frame header
       #
       # This class make a {Dot11} header with {#type} set to +2+
       # (data frame).
       #
@@ -25,33 +24,62 @@
       # * sometimes a {#qos_ctrl} ({Types::Int16}),
       # * a {#body} (a {Types::String} or another {Base} class),
       # * and a Frame check sequence ({#fcs}, of type {Types::Int32le}).
       # @author Sylvain Daubert
       class Data < Dot11
-
         # @param [Hash] options
         # @see Base#initialize
         def initialize(options={})
-          super({type: 2}.merge!(options))
-          @applicable_fields -= %i(mac4 qos_ctrl ht_ctrl)
+          super({ type: 2 }.merge!(options))
+          @applicable_fields -= %i[mac4 qos_ctrl ht_ctrl]
           define_applicable_fields
         end
 
+        # Invert source and destination addresses (see Table 8-19 from
+        # IEEE 802.11-2012 document to known which MAC is SA, and which
+        # one is DA).
+        # Also invert Receiver and Transmitter address in case ToDS and
+        # FromDS are true.
+        def reply!
+          ds = frame_ctrl & 3
+          case ds
+          when 0
+            # MAC1: RA/DA, MAC2: TA/SA
+            self[:mac1], self[:mac2] = self[:mac2], self[:mac1]
+          when 1
+            # MAC1: RA/BSSID, MAC2: TA/SA, MAC3: DA
+            self[:mac2], self[:mac1] = self[:mac1], self[:mac2]
+            self.to_ds = false
+            self.from_ds = true
+          when 2
+            # MAC1: RA/DA, MAC2: BSSID, MAC3: SA or BSSID
+            self[:mac1], self[:mac2] = self[:mac2], self[:mac1]
+            self.to_ds = true
+            self.from_ds = false
+          when 3
+            # MAC1: RA, MAC2: TA
+            self[:mac1], self[:mac2] = self[:mac2], self[:mac1]
+            # MAC3: DA, MAC4: SA
+            self[:mac4], self[:mac3] = self[:mac3], self[:mac4]
+          end
+          self
+        end
+
         private
 
         def define_applicable_fields
           super
-          if subtype >= 8 and !@applicable_fields.include? :qos_ctrl
+          if (subtype >= 8) && !@applicable_fields.include?(:qos_ctrl)
             # Insert after mac4, if present
             # else insert after sequence_ctrl
             if @applicable_fields.include? :mac4
               idx = @applicable_fields.index(:mac4)
               @applicable_fields[idx, 0] = :qos_ctrl
             else
               @applicable_fields[6, 0] = :qos_ctrl
             end
           elsif subtype < 8
-            @applicable_fields -= %i(qos_ctrl)
+            @applicable_fields -= %i[qos_ctrl]
           end
         end
       end
     end
   end