From 5ee383ea8c31cd7c8489c2b076aac9c51f63b55c Mon Sep 17 00:00:00 2001
From: Robin Gloster <mail@glob.in>
Date: Tue, 24 Sep 2019 11:41:12 +0200
Subject: [PATCH] nixos-generate-config: add useDHCP per interface

This sets networking.useDHCP to false and for all interfaces found the
per-interface useDHCP to true. This replicates the current default
behaviour and prepares for the switch to networkd.
---
 .../installer/tools/nixos-generate-config.pl  | 20 +++++++++++++++++++
 nixos/modules/installer/tools/tools.nix       |  1 +
 2 files changed, 21 insertions(+)

diff --git a/nixos/modules/installer/tools/nixos-generate-config.pl b/nixos/modules/installer/tools/nixos-generate-config.pl
index cfdbdaabf5c..f2ffe61c42c 100644
--- a/nixos/modules/installer/tools/nixos-generate-config.pl
+++ b/nixos/modules/installer/tools/nixos-generate-config.pl
@@ -563,6 +563,24 @@ $fsAndSwap
 ${\join "", (map { "  $_\n" } (uniq @attrs))}}
 EOF
 
+sub generateNetworkingDhcpConfig {
+    my $config = <<EOF;
+  # 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;
+EOF
+
+    foreach my $path (glob "/sys/class/net/*") {
+        my $dev = basename($path);
+        if ($dev ne "lo") {
+            $config .= "  networking.interfaces.$dev.useDHCP = true;\n";
+        }
+    }
+
+    return $config;
+}
+
 
 if ($showHardwareConfig) {
     print STDOUT $hwConfig;
@@ -606,6 +624,8 @@ EOF
 EOF
         }
 
+        my $networkingDhcpConfig = generateNetworkingDhcpConfig();
+
         write_file($fn, <<EOF);
 @configuration@
 EOF
diff --git a/nixos/modules/installer/tools/tools.nix b/nixos/modules/installer/tools/tools.nix
index 05add59117d..32926005959 100644
--- a/nixos/modules/installer/tools/tools.nix
+++ b/nixos/modules/installer/tools/tools.nix
@@ -96,6 +96,7 @@ in
         # networking.hostName = "nixos"; # Define your hostname.
         # networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.
 
+      $networkingDhcpConfig
         # Configure network proxy if necessary
         # networking.proxy.default = "http://user:password\@proxy:port/";
         # networking.proxy.noProxy = "127.0.0.1,localhost,internal.domain";