nixos/nixos-generate-config: move dhcpConfig from configuration.nix to hardware-configuration.nix

nixos/doc/manual/from_md/release-notes/rl-2205.section.xml

@@ -773,6 +773,13 @@
           loaded in the initrd.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          <literal>nixos-generate-config</literal> now puts the dhcp
+          configuration in <literal>hardware-configuration.nix</literal>
+          instead of <literal>configuration.nix</literal>.
+        </para>
+      </listitem>
       <listitem>
         <para>
           <literal>fetchFromSourcehut</literal> now allows fetching

nixos/doc/manual/release-notes/rl-2205.section.md

@@ -263,6 +263,8 @@ In addition to numerous new and upgraded packages, this release has the followin
 
 - A new option `boot.initrd.extraModprobeConfig` has been added which can be used to configure kernel modules that are loaded in the initrd.
 
+- `nixos-generate-config` now puts the dhcp configuration in `hardware-configuration.nix` instead of `configuration.nix`.
+
 - `fetchFromSourcehut` now allows fetching repositories recursively
   using `fetchgit` or `fetchhg` if the argument `fetchSubmodules`
   is set to `true`.

nixos/modules/installer/tools/nixos-generate-config.pl

@@ -558,6 +558,8 @@ if (!$noFilesystems) {
     $fsAndSwap .= "swapDevices =" . multiLineList("    ", @swapDevices) . ";\n";
 }
 
+my $networkingDhcpConfig = generateNetworkingDhcpConfig();
+
 my $hwConfig = <<EOF;
 # Do not modify this file!  It was generated by ‘nixos-generate-config’
 # and may be overwritten by future invocations.  Please make changes
@@ -572,6 +574,7 @@ my $hwConfig = <<EOF;
   boot.kernelModules = [$kernelModules ];
   boot.extraModulePackages = [$modulePackages ];
 $fsAndSwap
+$networkingDhcpConfig
 ${\join "", (map { "  $_\n" } (uniq @attrs))}}
 EOF
 
@@ -580,13 +583,13 @@ sub generateNetworkingDhcpConfig {
   # The global useDHCP flag is deprecated, therefore explicitly set to false here.
   # Per-interface useDHCP will be mandatory in the future, so this generated config
   # replicates the default behaviour.
-  networking.useDHCP = false;
+  networking.useDHCP = lib.mkDefault false;
 EOF
 
     foreach my $path (glob "/sys/class/net/*") {
         my $dev = basename($path);
         if ($dev ne "lo") {
-            $config .= "  networking.interfaces.$dev.useDHCP = true;\n";
+            $config .= "  networking.interfaces.$dev.useDHCP = lib.mkDefault true;\n";
         }
     }
 

nixos/modules/installer/tools/tools.nix

@@ -141,7 +141,6 @@ in
         # Set your time zone.
         # time.timeZone = "Europe/Amsterdam";
 
-      $networkingDhcpConfig
         # Configure network proxy if necessary
         # networking.proxy.default = "http://user:password\@proxy:port/";
         # networking.proxy.noProxy = "127.0.0.1,localhost,internal.domain";