From 9615317bf67831ceb901896e61b2dcf3955ed7a5 Mon Sep 17 00:00:00 2001
From: Astro <astro@spaceboyz.net>
Date: Thu, 8 Apr 2021 01:43:02 +0200
Subject: [PATCH] nixos-module/container/upstream: enable dhcpv6 prefix
 delegation

---
 nix/nixos-module/container/upstream.nix | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/nix/nixos-module/container/upstream.nix b/nix/nixos-module/container/upstream.nix
index 31c707d..941f73e 100644
--- a/nix/nixos-module/container/upstream.nix
+++ b/nix/nixos-module/container/upstream.nix
@@ -12,8 +12,25 @@ let
     else null;
 in
 {
-  systemd.network.networks = builtins.mapAttrs (_: { upstream, ... }: {
+  systemd.network.networks = {
+    core = {
+      # systemd-networkd only requests Prefix Delegation via DHCPv6 on
+      # the upstream interface if another interface is configured for it.
+      # without this, the static ipv6 subnet won't be routed to us.
+      extraConfig = ''
+        [Network]
+        IPv6PrefixDelegation=dhcpv6
+      '';
+      dhcpV6PrefixDelegationConfig = {
+        SubnetId = "81";
+        # because we have static addresses, we don't actually use this
+        Assign = false;
+      };
+    };
+  } // builtins.mapAttrs (_: { upstream, ... }: {
     DHCP = "yes";
+    networkConfig.IPv6AcceptRA = true;
+    dhcpV6Config.PrefixDelegationHint = "::/56";
 
     extraConfig = ''
       [CAKE]