Add shared-network configuration

manifests/init.pp

@@ -2,6 +2,8 @@
 #
 # @param option_static_route
 #   When enabled it sets the options rfc3442-classless-static-routes and ms-classless-static-routes
+# @param shared_network
+#   When used it configure subnet in shared-network statement, it is used to inform the DHCP server that it share the same physical network
 class dhcp (
   Array[String] $dnsdomain = $dhcp::params::dnsdomain,
   Array[String] $nameservers = [],
@@ -46,6 +48,7 @@
   Hash[String, Hash] $hosts = {},
   Variant[Array[String], Optional[String]] $includes = undef,
   String $config_comment = 'dhcpd.conf',
+  Optional[Hash[String, Hash]] $shared_networks = undef,
 ) inherits dhcp::params {
   # In case people set interface instead of interfaces work around
   # that. If they set both, use interfaces and the user is a unwise
@@ -157,6 +160,10 @@
     order   => '01',
   }
 
+  if $shared_networks {
+    create_resources('dhcp::sharednet', $shared_networks)
+  }
+
   create_resources('dhcp::subnet', $subnets)
   create_resources('dhcp::pool', $pools)
   create_resources('dhcp::host', $hosts)

manifests/sharednet.pp

@@ -0,0 +1,22 @@
+# @summary
+#   Define a DHCP shared-network
+# @param subnets
+#   subnets to include in the shared-network statement
+# @param order
+#   Fragment order in the dhcpd.conf
+define dhcp::sharednet (
+  Hash[String,Hash] $subnets = {},
+  Integer[1] $order = 75,
+) {
+  concat::fragment { "dhcp.conf+${order}-start_${name}.dhcp":
+    target  => "${dhcp::dhcp_dir}/dhcpd.conf",
+    content => "shared-network ${name} {\n",
+    order   => "${order}-0start",
+  }
+  concat::fragment { "dhcp.conf+${order}-end_${name}.dhcp":
+    target  => "${dhcp::dhcp_dir}/dhcpd.conf",
+    content => "}\n",
+    order   => "${order}-9end",
+  }
+  create_resources('dhcp::subnet', $subnets, { order => $order })
+}

manifests/subnet.pp

@@ -45,6 +45,8 @@
 #   Partial that is appended to the dhcpd.conf (before the final `}`)
 # @param raw_prepend
 #   Partial that is prepended to the dhcpd.conf (after the first `{`)
+# @param order
+#   Fragment order in the dhcpd.conf
 define dhcp::subnet (
   Stdlib::IP::Address::Nosubnet $network,
   Stdlib::IP::Address::Nosubnet $mask,
@@ -61,10 +63,11 @@
   Variant[Array[String], Optional[String]] $search_domains = undef,
   Optional[String] $raw_append = undef,
   Optional[String] $raw_prepend = undef,
+  Integer[1] $order = 70,
 ) {
-  concat::fragment { "dhcp.conf+70_${name}.dhcp":
+  concat::fragment { "dhcp.conf+${order}_${name}.dhcp":
     target  => "${dhcp::dhcp_dir}/dhcpd.conf",
     content => template('dhcp/dhcpd.subnet.erb'),
-    order   => "70-${name}",
+    order   => "${order}-${name}",
   }
 }

spec/acceptance/shared_spec.rb

@@ -0,0 +1,41 @@
+require 'spec_helper_acceptance'
+
+describe 'Simple installation' do
+  interface = 'eth0'
+  config_file = fact('os.family') == 'Archlinux' ? '/etc/dhcpd.conf' : '/etc/dhcp/dhcpd.conf'
+
+  it_behaves_like 'an idempotent resource' do
+    let(:manifest) do
+      <<-EOS
+      $interface = $facts['networking']['interfaces']['#{interface}']
+
+      class { 'dhcp':
+        interfaces     => ['#{interface}'],
+        shared_networks => {
+          'shared' => {
+            subnets => {
+              $interface['network'] => {
+                network => $interface['network'],
+                mask => $interface['netmask'],
+                pools => [],
+              },
+              '172.20.0.0' => {
+                network => '172.20.0.0',
+                mask => '255.255.255.0',
+                pools => [],
+              }
+            }
+          }
+        },
+      }
+      EOS
+    end
+  end
+
+  it_behaves_like 'a DHCP server'
+
+  describe file(config_file) do
+    it { is_expected.to be_file }
+    its(:content) { should match(/shared-network shared/) }
+  end
+end

spec/classes/init_spec.rb

@@ -534,6 +534,20 @@
           it { is_expected.to compile.and_raise_error(%r{dnsupdateserver or nameservers parameter is required to enable ddns}) }
         end
       end
+
+      describe "with shared_network" do
+          let(:params) { super().merge(shared_network: "shared") }
+
+          let(:expected_content) do
+            <<~CONTENT
+              shared-network shared {
+            CONTENT
+          end
+
+          it do
+            is_expected.to contain_concat__fragment('dhcp.conf+75-start_shared.dhcp').with_content(expected_content)
+          end
+      end
     end
   end
 end