providers/docker: support for UDP forwarded ports [GH-3886]

CHANGELOG.md

@@ -12,6 +12,7 @@ IMPROVEMENTS:
   - commands/box/add: `--capath` flag added for custom CA path. [GH-3848]
   - commands/halt: Halt in reverse order of up, like destroy. [GH-3790]
   - hosts/linux: Uses rdesktop to RDP into machines if available. [GH-3845]
+  - providers/docker: Support for UDP forwarded ports. [GH-3886]
   - provisioners/salt: Works on Windows guests. [GH-3825]
 
 BUG FIXES:

plugins/providers/docker/action/create.rb

@@ -124,8 +124,9 @@ module VagrantPlugins
           end
 
           mappings.values.map do |fp|
-            # TODO: Support for the protocol argument
-            "#{fp[:host]}:#{fp[:guest]}"
+            protocol = ""
+            protocol = "/udp" if fp[:protocol].to_s == "udp"
+            "#{fp[:host]}:#{fp[:guest]}#{protocol}"
           end.compact
         end
       end