nixpkgs/nixos/modules/services/networking/kresd.nix
Vladimír Čunát 3ab85ed1ac
nixos/kresd: use DNSSEC root trust anchor from nixpkgs
in read-only way.  If the cache directory is empty and you use the
very same service for system's DNS, kresd is unable to bootstrap root
trust anchors, as it would need a DNS lookup.

Also, if we don't rely on bootstrap, the extra lua deps of kresd could
be dropped by default, but let's not do that now, as the difference in
closure size is only ~4 MB, and there may be other use cases than
running the package as nixos service this way.
2018-01-09 17:24:49 +01:00

108 lines
2.8 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.kresd;
package = pkgs.knot-resolver;
configFile = pkgs.writeText "kresd.conf" cfg.extraConfig;
in
{
meta.maintainers = [ maintainers.vcunat /* upstream developer */ ];
###### interface
options.services.kresd = {
enable = mkOption {
type = types.bool;
default = false;
description = ''
Whether to enable knot-resolver domain name server.
DNSSEC validation is turned on by default.
You can run <literal>sudo nc -U /run/kresd/control</literal>
and give commands interactively to kresd.
'';
};
extraConfig = mkOption {
type = types.lines;
default = "";
description = ''
Extra lines to be added verbatim to the generated configuration file.
'';
};
cacheDir = mkOption {
type = types.path;
default = "/var/cache/kresd";
description = ''
Directory for caches. They are intended to survive reboots.
'';
};
interfaces = mkOption {
type = with types; listOf str;
default = [ "::1" "127.0.0.1" ];
description = ''
What addresses the server should listen on.
'';
};
# TODO: perhaps options for more common stuff like cache size or forwarding
};
###### implementation
config = mkIf cfg.enable {
environment.etc."kresd.conf".source = configFile; # not required
users.extraUsers = singleton
{ name = "kresd";
uid = config.ids.uids.kresd;
group = "kresd";
description = "Knot-resolver daemon user";
};
users.extraGroups = singleton
{ name = "kresd";
gid = config.ids.gids.kresd;
};
systemd.sockets.kresd = rec {
wantedBy = [ "sockets.target" ];
before = wantedBy;
listenStreams = map
# Syntax depends on being IPv6 or IPv4.
(iface: if elem ":" (stringToCharacters iface) then "[${iface}]:53" else "${iface}:53")
cfg.interfaces;
socketConfig.ListenDatagram = listenStreams;
};
systemd.sockets.kresd-control = rec {
wantedBy = [ "sockets.target" ];
before = wantedBy;
partOf = [ "kresd.socket" ];
listenStreams = [ "/run/kresd/control" ];
socketConfig = {
FileDescriptorName = "control";
Service = "kresd.service";
SocketMode = "0660"; # only root user/group may connect
};
};
systemd.tmpfiles.rules = [ "d '${cfg.cacheDir}' 0770 kresd kresd - -" ];
systemd.services.kresd = {
description = "Knot-resolver daemon";
serviceConfig = {
User = "kresd";
Type = "notify";
WorkingDirectory = cfg.cacheDir;
};
script = ''
exec '${package}/bin/kresd' --config '${configFile}' \
-k '${pkgs.dns-root-data}/root.key'
'';
requires = [ "kresd.socket" ];
};
};
}