Import workspace IP validation from Mdm

This allows us to actually test the validations, since the code calls
out to Rex::Socket::RangeWalker.

MS-902

app/concerns/mdm/workspace/boundary_range.rb

@@ -0,0 +1,60 @@
+module Mdm::Workspace::BoundaryRange
+  extend ActiveSupport::Concern
+
+  included do
+    #
+    # Validations
+    #
+
+    validate :boundary_must_be_ip_range
+
+    #
+    # Instance Methods
+    #
+
+    # If {#limit_to_network} is disabled, this will always return `true`.
+    # Otherwise, return `true` only if all of the given IPs are within the
+    # project {#boundary boundaries}.
+
+    #
+    # @param ips [String] IP range(s)
+    # @return [true] if actions on ips are allowed.
+    # @return [false] if actions are not allowed on ips.
+    def allow_actions_on?(ips)
+      return true unless limit_to_network
+      return true unless boundary
+      return true if boundary.empty?
+      boundaries = Shellwords.split(boundary)
+      return true if boundaries.empty? # It's okay if there is no boundary range after all
+      given_range = Rex::Socket::RangeWalker.new(ips)
+      return false unless given_range # Can't do things to nonexistant IPs
+      allowed = false
+      boundaries.each do |boundary_range|
+        ok_range = Rex::Socket::RangeWalker.new(boundary)
+        allowed  = true if ok_range.include_range? given_range
+      end
+      return allowed
+    end
+
+    # Validates that {#boundary} is {#valid_ip_or_range? a valid IP address or
+    # IP address range}. Due to this not being tested before it was moved here
+    # from Mdm, the default workspace does not validate. We therefore don't
+    # validate boundaries of workspaces that don't use them.
+    #
+    # @return [void]
+    def boundary_must_be_ip_range
+      errors.add(:boundary, "must be a valid IP range") unless !limit_to_network || valid_ip_or_range?(boundary)
+    end
+
+    private
+
+    # Returns whether `string` is a valid IP address or IP address range.
+    #
+    # @return [true] if valid IP address or IP address range.
+    # @return [false] otherwise.
+    def valid_ip_or_range?(string)
+      range = Rex::Socket::RangeWalker.new(string)
+      range && range.ranges && range.ranges.any?
+    end
+  end
+end