More util functions

lib.nix

@@ -36,8 +36,13 @@ let
   getDomainHosts = domain:
     attrNames
     (filterAttrs (_: hostOpts: hostOpts.domain == domain) entities.hosts);
+
+  getSiteGateway = site: entities.sites."${site-name}".gateway-v4;
+
+  getHostGateway = hostname: (getHostSite hostname).gateway-v4;
+
 in {
   inherit getHostSite getHostDomain getHostRealm getHostFqdn getHostIpv4
-    getHostIpv6 getHostIps getDomainPostgresqlServer getSiteHosts
-    getDomainHosts;
+    getHostIpv6 getHostIps getDomainPostgresqlServer getSiteHosts getDomainHosts
+    getSiteGateway getHostGateway;
 }