providers/virtualbox: workaround IPv6 routing bug in VB

VirtualBox has a bug where the IPv6 route is lost on every other
configuration of a host-only network. This is also triggered when a VM
is booted.

To fix this, we test the route-ability of all IPv6 networks, and
reconfigure if necessary. This is very fast but we still only do this if
we have any IPv6 networks.

plugins/providers/virtualbox/action.rb

@@ -30,6 +30,7 @@ module VagrantPlugins
       autoload :MessageNotRunning, File.expand_path("../action/message_not_running", __FILE__)
       autoload :MessageWillNotDestroy, File.expand_path("../action/message_will_not_destroy", __FILE__)
       autoload :Network, File.expand_path("../action/network", __FILE__)
+      autoload :NetworkFixIPv6, File.expand_path("../action/network_fix_ipv6", __FILE__)
       autoload :Package, File.expand_path("../action/package", __FILE__)
       autoload :PackageVagrantfile, File.expand_path("../action/package_vagrantfile", __FILE__)
       autoload :PrepareNFSSettings, File.expand_path("../action/prepare_nfs_settings", __FILE__)
@@ -63,6 +64,7 @@ module VagrantPlugins
           b.use PrepareNFSSettings
           b.use ClearNetworkInterfaces
           b.use Network
+          b.use NetworkFixIPv6
           b.use ForwardPorts
           b.use SetHostname
           b.use SaneDefaults

plugins/providers/virtualbox/action/network_fix_ipv6.rb

@@ -0,0 +1,64 @@
+require "ipaddr"
+require "socket"
+
+require "log4r"
+
+require "vagrant/util/scoped_hash_override"
+
+module VagrantPlugins
+  module ProviderVirtualBox
+    module Action
+      # This middleware works around a bug in VirtualBox where booting
+      # a VM with an IPv6 host-only network will someties lose the
+      # route to that machine.
+      class NetworkFixIPv6
+        include Vagrant::Util::ScopedHashOverride
+
+        def initialize(app, env)
+          @logger = Log4r::Logger.new("vagrant::plugins::virtualbox::network")
+          @app    = app
+        end
+
+        def call(env)
+          @env = env
+
+          # Determine if we have an IPv6 network
+          has_v6 = false
+          env[:machine].config.vm.networks.each do |type, options|
+            next if type != :private_network
+            options = scoped_hash_override(options, :virtualbox)
+            next if options[:ip] == ""
+            if IPAddr.new(options[:ip]).ipv6?
+              has_v6 = true
+              break
+            end
+          end
+
+          # Call up
+          @app.call(env)
+
+          # If we have no IPv6, forget it
+          return if !has_v6
+
+          # We do, so fix them if we must
+          env[:machine].provider.driver.read_host_only_interfaces.each do |interface|
+            # Ignore interfaces without an IPv6 address
+            next if interface[:ipv6] == ""
+
+            # Make the test IP. This is just the highest value IP
+            ip = IPAddr.new(interface[:ipv6])
+            ip |= IPAddr.new(":#{":FFFF" * (interface[:ipv6_prefix].to_i / 16)}")
+
+            @logger.info("testing IPv6: #{ip}")
+            begin
+              UDPSocket.new(Socket::AF_INET6).connect(ip.to_s, 80)
+            rescue Errno::EHOSTUNREACH
+              @logger.info("IPv6 host unreachable. Fixing: #{ip}")
+              env[:machine].provider.driver.reconfig_host_only(interface)
+            end
+          end
+        end
+      end
+    end
+  end
+end

plugins/providers/virtualbox/driver/base.rb

@@ -263,6 +263,14 @@ module VagrantPlugins
         def read_vms
         end
 
+        # Reconfigure the hostonly network given by interface (the result
+        # of read_host_only_networks). This is a sad function that only
+        # exists to work around VirtualBox bugs.
+        #
+        # @return nil
+        def reconfig_host_only(interface)
+        end
+
         # Removes the DHCP server identified by the provided network name.
         #
         # @param [String] network_name The the full network name associated

plugins/providers/virtualbox/driver/meta.rb

@@ -109,6 +109,7 @@ module VagrantPlugins
           :read_state,
           :read_used_ports,
           :read_vms,
+          :reconfig_host_only,
           :remove_dhcp_server,
           :resume,
           :set_mac_address,

plugins/providers/virtualbox/driver/version_4_3.rb

@@ -72,6 +72,11 @@ module VagrantPlugins
           }
         end
 
+        def reconfig_host_only(interface)
+          execute("hostonlyif", "ipconfig", interface[:name],
+                  "--ipv6", interface[:ipv6])
+        end
+
         def delete
           execute("unregistervm", @uuid, "--delete")
         end

plugins/providers/virtualbox/driver/version_5_0.rb

@@ -488,6 +488,11 @@ module VagrantPlugins
           results
         end
 
+        def reconfig_host_only(interface)
+          execute("hostonlyif", "ipconfig", interface[:name],
+                  "--ipv6", interface[:ipv6])
+        end
+
         def remove_dhcp_server(network_name)
           execute("dhcpserver", "remove", "--netname", network_name)
         end