From d600da70457a8ca8d9543eb48b73e7c5eae1656f Mon Sep 17 00:00:00 2001
From: Andreas Rammhold <andreas@rammhold.de>
Date: Sat, 11 May 2019 00:28:24 +0200
Subject: [PATCH] nixos/networkd: use the route section for default routes

With systemd v242 using the `Gateway` attribute of the `[Network]`
section will lead to "onlink" routes on all the device that are matched
by the default configuration (typically all devices) causing multiple
default routes (even on localhost).

We can only avoid that - while keeping our default route option - when
we mark the route as explicitly not on link. Only gateways that are
within a subnet of one of the assigned interface addresses will be
installed into the routing table.
---
 nixos/modules/tasks/network-interfaces-systemd.nix | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/tasks/network-interfaces-systemd.nix b/nixos/modules/tasks/network-interfaces-systemd.nix
index dd9ba9eec42..b9c1387cea5 100644
--- a/nixos/modules/tasks/network-interfaces-systemd.nix
+++ b/nixos/modules/tasks/network-interfaces-systemd.nix
@@ -59,7 +59,14 @@ in
           in {
             DHCP = override (dhcpStr cfg.useDHCP);
           } // optionalAttrs (gateway != [ ]) {
-            gateway = override gateway;
+            routes = override [
+              {
+                routeConfig = {
+                  Gateway = gateway;
+                  GatewayOnlink = false;
+                };
+              }
+            ];
           } // optionalAttrs (domains != [ ]) {
             domains = override domains;
           };