Add interfaces_list capability to get list of interfaces via biosdevname

or dmesg parsing.

plugins/guests/redhat/cap/interfaces_list.rb

@@ -0,0 +1,32 @@
+module VagrantPlugins
+  module GuestRedHat
+    module Cap
+      class InterfacesList
+        def self.interfaces_list(machine)
+          version =  String.new
+          machine.communicate.sudo("cat /etc/redhat-release | sed -e 's/.*release\ //' | cut -f1 -d' '") do |_, result|
+            # Only care about the major version for now
+            version = result.split('.').first
+          end
+          
+          interface_names = Array.new
+
+          # In theory this would work with even older versions as dmesg has been relatively static for a long time
+          if version.to_i < 6
+            machine.communicate.sudo("dmesg | cut -f2 -d: | sed -e 's/^\ //' | sed -e 's/\ .*$//' | grep eth") do |_, result|
+              # It has two results ? - Quick hack to compensate
+              interface_names = result.split("\n").uniq.sort if interface_names.empty?
+            end
+          else
+            machine.communicate.sudo("biosdevname -d | grep Kernel | cut -f2 -d: | sed -e 's/ //;'") do |_, result|
+              # The previous had two results.  This one never has.  Do the same check for now.
+              interface_names = result.split("\n") if interface_names.empty?
+            end
+          end
+          
+          return interface_names
+        end
+      end
+    end
+  end
+end

plugins/guests/redhat/plugin.rb

@@ -35,6 +35,11 @@ module VagrantPlugins
         require_relative "cap/rsync"
         Cap::RSync
       end
+      
+      guest_capability("redhat", "interfaces_list") do
+        require_relative "cap/interfaces_list"
+        Cap::InterfacesList
+      end
     end
   end
 end