From fa66b887b8b5132642095baeb1c4d8846b00741a Mon Sep 17 00:00:00 2001
From: Max <max@privatevoid.net>
Date: Wed, 17 Jul 2024 21:57:45 +0200
Subject: [PATCH] checks/simulacrum: better networking

---
 packages/checks/simulacrum.nix | 40 ++++++++++++++++++++++++++++++----
 1 file changed, 36 insertions(+), 4 deletions(-)

diff --git a/packages/checks/simulacrum.nix b/packages/checks/simulacrum.nix
index 522d17b..39d92d3 100644
--- a/packages/checks/simulacrum.nix
+++ b/packages/checks/simulacrum.nix
@@ -21,9 +21,7 @@ let
       ({ config, ... }: {
         gods.fromLight = lib.mapAttrs (name: cfg: {
           interfaces.primary = {
-            link = lib.mkForce "eth1";
-            addr = lib.mkForce "192.168.1.${toString digits.${name}}";
-            addrPublic = lib.mkForce "192.168.1.${toString digits.${name}}";
+            link = lib.mkForce "vprimary";
           };
           ssh.id.publicKey = lib.mkForce snakeoil.ssh.public;
         }) lift.gods.fromLight;
@@ -50,13 +48,47 @@ testers.runNixOSTest {
   name = "simulacrum";
 
   node = { inherit specialArgs; };
-  nodes = lib.genAttrs nodes (node: {
+  nodes = lib.genAttrs nodes (node: let
+    hour = depot'.config.hours.${node};
+  in {
     imports = [
       specialArgs.depot.hours.${node}.nixos
       ./modules/nixos/age-dummy-secrets
       ./modules/nixos/external-storage.nix
     ] ++ depot'.config.cluster.config.out.injectNixosConfig node;
 
+    boot.kernel.sysctl."net.ipv4.ip_forward" = "1";
+    networking = {
+      interfaces = {
+        ${hour.interfaces.primary.link} = {
+          useDHCP = lib.mkForce false;
+          virtual = true;
+          ipv4.addresses = lib.mkForce [
+            {
+              address = hour.interfaces.primary.addr;
+              prefixLength = 32;
+            }
+          ];
+        };
+        eth1.ipv4.routes = lib.pipe nodes [
+          (lib.filter (n: n != node))
+          (map (n: let
+            hour = depot'.config.hours.${n};
+          in {
+            address = hour.interfaces.primary.addrPublic;
+            prefixLength = 32;
+            via = "192.168.1.${toString digits.${n}}";
+          }))
+        ];
+      };
+
+      firewall.extraCommands = lib.mkAfter (lib.optionalString (hour.interfaces.primary.isNat) ''
+        # self-nat
+        iptables -t nat -A PREROUTING -d ${hour.interfaces.primary.addrPublic} -j DNAT --to-destination ${hour.interfaces.primary.addr}
+        iptables -t nat -A POSTROUTING -s ${hour.interfaces.primary.addr} -j SNAT --to-source ${hour.interfaces.primary.addrPublic}
+      '');
+    };
+
     systemd.services = {
       hyprspace.enable = false;
       cachix-agent.enable = false;