services/router: init

modules/clan/router/acme-secret.nix

@@ -0,0 +1,22 @@
+# Shared TSIG secret for a gateway's dedicated ACME key (function: machine
+# name -> NixOS module). The acme_<machine> key lets that gateway — and only
+# it — write _acme-challenge.<site><siteId> TXT records on the authoritative
+# nameserver to obtain its internal wildcard cert via DNS-01 (proxy.nix).
+#
+# The router service declares it on the gateway automatically when
+# proxy.enable is set. The nameserver machine must declare the very same
+# generator so both sides share one secret:
+#   imports = [ (import <router-service>/acme-secret.nix "gw-cnx-1") ];
+# and then load it into its DNS server as key acme_gw_cnx_1 (hmac-sha256)
+# with an acl scoped to that gateway's _acme-challenge label.
+machine:
+{ pkgs, ... }:
+{
+  clan.core.vars.generators."dns-acme-${machine}-secret" = {
+    share = true;
+    files."secret".secret = true;
+    runtimeInputs = [ pkgs.openssl ];
+    # 32 random bytes, base64 — a valid hmac-sha256 TSIG secret.
+    script = ''openssl rand -base64 32 | tr -d '\n' > "$out"/secret'';
+  };
+}