Support libvirt built-in TFTP server (#1412)

Adds support for libvirt TFTP server, for netboot environments.

(vide: https://libvirt.org/formatnetwork.html#elementsAddress)

README.md

@@ -859,6 +859,7 @@ starts with `libvirt__` string. Here is a list of those options:
 * `:libvirt__dhcp_bootp_server` - The server that runs the DHCP server.  Used
   only when dhcp is enabled.By default is the same host that runs the DHCP
   server.
+* `:libvirt__tftp_root` - Path to the root directory served via TFTP.
 * `:libvirt__adapter` - Number specifiyng sequence number of interface.
 * `:libvirt__forward_mode` - Specify one of `veryisolated`, `none`, `open`, `nat`
   or `route` options.  This option is used only when creating new network. Mode

lib/vagrant-libvirt/action/create_networks.rb

@@ -352,6 +352,10 @@ module VagrantPlugins
             @network_dhcp_enabled = false
           end
 
+          if @options[:tftp_root]
+            @tftp_root = @options[:tftp_root]
+          end
+
           @network_domain_name = @options[:domain_name]
 
           begin

lib/vagrant-libvirt/templates/private_network.xml.erb

@@ -20,6 +20,9 @@
 
   <% if @network_forward_mode != 'veryisolated' %>
     <ip address="<%= @network_address %>" netmask="<%= @network_netmask %>">
+    <% if @tftp_root %>
+      <tftp root="<%= @tftp_root %>" />
+    <% end %>
     <% if @network_dhcp_enabled  %>
       <dhcp>
         <range start="<%= @network_range_start %>" end="<%= @network_range_stop %>" />