From a19f0871f481eaa429ecf1e714e49194169ae848 Mon Sep 17 00:00:00 2001
From: Max <max@privatevoid.net>
Date: Sat, 10 Aug 2024 13:37:14 +0200
Subject: [PATCH] cluster/simulacrum: implement nowhere, fix networking

---
 cluster/simulacrum/default.nix         |  17 ++++-
 cluster/simulacrum/nowhere/default.nix | 101 +++++++++++++++++++++++++
 cluster/simulacrum/nowhere/options.nix |  16 ++++
 3 files changed, 131 insertions(+), 3 deletions(-)
 create mode 100644 cluster/simulacrum/nowhere/default.nix
 create mode 100644 cluster/simulacrum/nowhere/options.nix

diff --git a/cluster/simulacrum/default.nix b/cluster/simulacrum/default.nix
index a900de7..101b345 100644
--- a/cluster/simulacrum/default.nix
+++ b/cluster/simulacrum/default.nix
@@ -17,7 +17,8 @@ let
   };
 
   nodes = lib.attrNames config.gods.fromLight;
-  digits = lib.attrsets.listToAttrs (lib.zipListsWith lib.nameValuePair nodes (lib.range 1 255));
+  nodes' = lib.attrNames (config.gods.fromLight // { nowhere = null; });
+  digits = lib.attrsets.listToAttrs (lib.zipListsWith lib.nameValuePair nodes' (lib.range 1 255));
   depot' = extendModules {
     modules = [
       ({ config, ... }: {
@@ -51,6 +52,12 @@ testers.runNixOSTest {
 
   imports = [
     serviceConfig.simulacrum.settings
+    ./nowhere
+    {
+      nodes.nowhere.imports = [
+        config.flake.nixosModules.port-magic
+      ];
+    }
   ] ++ allAugments;
 
   _module.args = {
@@ -73,12 +80,15 @@ testers.runNixOSTest {
         ${hour.interfaces.primary.link} = {
           useDHCP = lib.mkForce false;
           virtual = true;
-          ipv4.addresses = lib.mkForce [
+          ipv4.addresses = lib.mkForce ([
             {
               address = hour.interfaces.primary.addr;
               prefixLength = 32;
             }
-          ];
+          ] ++ lib.optional hour.interfaces.primary.isNat {
+            address = hour.interfaces.primary.addrPublic;
+            prefixLength = 32;
+          });
         };
         eth1.ipv4.routes = lib.pipe nodes [
           (lib.filter (n: n != node))
@@ -95,6 +105,7 @@ testers.runNixOSTest {
       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 OUTPUT -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}
       '');
     };
diff --git a/cluster/simulacrum/nowhere/default.nix b/cluster/simulacrum/nowhere/default.nix
new file mode 100644
index 0000000..4e3aaaf
--- /dev/null
+++ b/cluster/simulacrum/nowhere/default.nix
@@ -0,0 +1,101 @@
+{ cluster, config, lib, pkgs, ... }:
+
+let
+  lift = config;
+
+  cfsslConfigIntermediateCA = pkgs.writeText "simulacrum-cfssl-config.json" (builtins.toJSON {
+    signing = {
+      default.expiry = "8760h";
+      profiles.intermediate = {
+        expiry = "8760h";
+        usages = [
+          "cert sign"
+          "crl sign"
+        ];
+        ca_constraint = {
+          is_ca = true;
+          max_path_len = 1;
+        };
+      };
+    };
+  });
+
+  caCsr = pkgs.writeText "simulacrum-ca-csr.json" (builtins.toJSON {
+    CN = "Simulacrum Root CA";
+  });
+
+  ca = pkgs.runCommand "simulacrum-snakeoil-ca" {
+    nativeBuildInputs = [
+      pkgs.cfssl
+    ];
+  } ''
+    mkdir $out
+    cfssl gencert --initca ${caCsr} | cfssljson --bare $out/ca
+  '';
+
+  genCert = extraFlags: csrData: let
+    csr = pkgs.writeText "simulacrum-csr.json" (builtins.toJSON csrData);
+  in pkgs.runCommand "simulacrum-snakeoil-cert" {
+    nativeBuildInputs = [
+      pkgs.cfssl
+    ];
+  } ''
+    mkdir $out
+    cfssl gencert ${lib.escapeShellArgs ([
+      "--ca=file:${ca}/ca.pem"
+      "--ca-key=file:${ca}/ca-key.pem"
+    ] ++ extraFlags ++ [
+      csr
+    ])} | cfssljson --bare $out/cert
+  '';
+
+  genHostCert = hostname: genCert [ "--hostname=${hostname}" ] { CN = hostname; };
+
+  getNodeAddr = node: (builtins.head config.nodes.${node}.networking.interfaces.eth1.ipv4.addresses).address;
+in
+
+{
+  imports = [
+    ./options.nix
+  ];
+  defaults = {
+    networking.hosts."${getNodeAddr "nowhere"}" = lib.attrNames config.nowhere.names;
+    security.pki.certificateFiles = [
+      "${ca}/ca.pem"
+    ];
+  };
+
+  nowhere.certs = {
+    inherit ca;
+    intermediate = genCert [ "--config=${cfsslConfigIntermediateCA}" "--profile=intermediate" ] {
+      CN = "Simulacrum Intermediate CA";
+    };
+  };
+
+  nodes.nowhere = { config, depot, ... }: {
+    networking = {
+      firewall.allowedTCPPorts = [ 443 ];
+      interfaces.eth1.ipv4.routes = lib.mapAttrsToList (name: hour: {
+        address = hour.interfaces.primary.addrPublic;
+        prefixLength = 32;
+        via = getNodeAddr name;
+      }) depot.gods.fromLight;
+      nameservers = map (name: depot.hours.${name}.interfaces.primary.addrPublic) cluster.config.services.dns.nodes.authoritative;
+    };
+    services.nginx = {
+      enable = true;
+      recommendedProxySettings = true;
+      virtualHosts = lib.mapAttrs (name: link: let
+        cert = genHostCert name;
+      in {
+        forceSSL = true;
+        sslCertificate = "${cert}/cert.pem";
+        sslCertificateKey = "${cert}/cert-key.pem";
+        locations."/" = {
+          proxyPass = config.links.${link}.url;
+          extraConfig = "proxy_ssl_verify off;";
+        };
+      }) lift.nowhere.names;
+    };
+  };
+}
diff --git a/cluster/simulacrum/nowhere/options.nix b/cluster/simulacrum/nowhere/options.nix
new file mode 100644
index 0000000..b0420b6
--- /dev/null
+++ b/cluster/simulacrum/nowhere/options.nix
@@ -0,0 +1,16 @@
+{ lib, ... }:
+
+{
+  options.nowhere = {
+    names = lib.mkOption {
+      description = "Hostnames that point Nowhere.";
+      type = with lib.types; attrsOf str;
+      default = {};
+    };
+    certs = lib.mkOption {
+      description = "Snakeoil certificate packages.";
+      type = with lib.types; attrsOf package;
+      default = {};
+    };
+  };
+}