{ config, lib, pkgs, ... }: with lib; let cfg = config.services.dnscache; dnscache-root = pkgs.runCommand "dnscache-root" { preferLocalBuild = true; } '' mkdir -p $out/{servers,ip} ${concatMapStrings (ip: '' touch "$out/ip/"${lib.escapeShellArg ip} '') cfg.clientIps} ${concatStrings (mapAttrsToList (host: ips: '' ${concatMapStrings (ip: '' echo ${lib.escapeShellArg ip} >> "$out/servers/"${lib.escapeShellArg host} '') ips} '') cfg.domainServers)} # if a list of root servers was not provided in config, copy it # over. (this is also done by dnscache-conf, but we 'rm -rf # /var/lib/dnscache/root' below & replace it wholesale with this, # so we have to ensure servers/@ exists ourselves.) if [ ! -e $out/servers/@ ]; then # symlink does not work here, due chroot cp ${pkgs.djbdns}/etc/dnsroots.global $out/servers/@; fi ''; in { ###### interface options = { services.dnscache = { enable = mkOption { default = false; type = types.bool; description = "Whether to run the dnscache caching dns server."; }; ip = mkOption { default = "0.0.0.0"; type = types.str; description = "IP address on which to listen for connections."; }; clientIps = mkOption { default = [ "127.0.0.1" ]; type = types.listOf types.str; description = "Client IP addresses (or prefixes) from which to accept connections."; example = ["192.168" "172.23.75.82"]; }; domainServers = mkOption { default = { }; type = types.attrsOf (types.listOf types.str); description = '' Table of {hostname: server} pairs to use as authoritative servers for hosts (and subhosts). If entry for @ is not specified predefined list of root servers is used. ''; example = { "@" = ["8.8.8.8" "8.8.4.4"]; "example.com" = ["192.168.100.100"]; }; }; forwardOnly = mkOption { default = false; type = types.bool; description = '' Whether to treat root servers (for @) as caching servers, requesting addresses the same way a client does. This is needed if you want to use e.g. Google DNS as your upstream DNS. ''; }; }; }; ###### implementation config = mkIf config.services.dnscache.enable { environment.systemPackages = [ pkgs.djbdns ]; users.users.dnscache.isSystemUser = true; systemd.services.dnscache = { description = "djbdns dnscache server"; wantedBy = [ "multi-user.target" ]; path = with pkgs; [ bash daemontools djbdns ]; preStart = '' rm -rf /var/lib/dnscache dnscache-conf dnscache dnscache /var/lib/dnscache ${config.services.dnscache.ip} rm -rf /var/lib/dnscache/root ln -sf ${dnscache-root} /var/lib/dnscache/root ''; script = '' cd /var/lib/dnscache/ ${optionalString cfg.forwardOnly "export FORWARDONLY=1"} exec ./run ''; }; }; }