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{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.kresd;
# Convert systemd-style address specification to kresd config line(s).
# On Nix level we don't attempt to precisely validate the address specifications.
mkListen = kind: addr: let
al_v4 = builtins.match "([0-9.]\+):([0-9]\+)" addr;
al_v6 = builtins.match "\\[(.\+)]:([0-9]\+)" addr;
al_portOnly = builtins.match "()([0-9]\+)" addr;
al = findFirst (a: a != null)
(throw "services.kresd.*: incorrect address specification '${addr}'")
[ al_v4 al_v6 al_portOnly ];
port = last al;
addrSpec = if al_portOnly == null then "'${head al}'" else "{'::', '127.0.0.1'}";
in # freebind is set for compatibility with earlier kresd services;
# it could be configurable, for example.
''
net.listen(${addrSpec}, ${port}, { kind = '${kind}', freebind = true })
'';
configFile = pkgs.writeText "kresd.conf" (
optionalString (cfg.listenDoH != []) ''
modules.load('http')
''
+ concatMapStrings (mkListen "dns") cfg.listenPlain
+ concatMapStrings (mkListen "tls") cfg.listenTLS
+ concatMapStrings (mkListen "doh") cfg.listenDoH
+ cfg.extraConfig
);
package = if cfg.listenDoH == []
then pkgs.knot-resolver # never force `extraFeatures = false`
else pkgs.knot-resolver.override { extraFeatures = true; };
in {
meta.maintainers = [ maintainers.vcunat /* upstream developer */ ];
imports = [
(mkChangedOptionModule [ "services" "kresd" "interfaces" ] [ "services" "kresd" "listenPlain" ]
(config:
let value = getAttrFromPath [ "services" "kresd" "interfaces" ] config;
in map
(iface: if elem ":" (stringToCharacters iface) then "[${iface}]:53" else "${iface}:53") # Syntax depends on being IPv6 or IPv4.
value
)
)
(mkRemovedOptionModule [ "services" "kresd" "cacheDir" ] "Please use (bind-)mounting instead.")
];
###### 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/knot-resolver/control/1</literal>
and give commands interactively to kresd@1.service.
'';
};
extraConfig = mkOption {
type = types.lines;
default = "";
description = ''
Extra lines to be added verbatim to the generated configuration file.
'';
};
listenPlain = mkOption {
type = with types; listOf str;
default = [ "[::1]:53" "127.0.0.1:53" ];
example = [ "53" ];
description = ''
What addresses and ports the server should listen on.
For detailed syntax see ListenStream in man systemd.socket.
'';
};
listenTLS = mkOption {
type = with types; listOf str;
default = [];
example = [ "198.51.100.1:853" "[2001:db8::1]:853" "853" ];
description = ''
Addresses and ports on which kresd should provide DNS over TLS (see RFC 7858).
For detailed syntax see ListenStream in man systemd.socket.
'';
};
listenDoH = mkOption {
type = with types; listOf str;
default = [];
example = [ "198.51.100.1:443" "[2001:db8::1]:443" "443" ];
description = ''
Addresses and ports on which kresd should provide DNS over HTTPS (see RFC 8484).
For detailed syntax see ListenStream in man systemd.socket.
'';
};
instances = mkOption {
type = types.ints.unsigned;
default = 1;
description = ''
The number of instances to start. They will be called kresd@{1,2,...}.service.
Knot Resolver uses no threads, so this is the way to scale.
You can dynamically start/stop them at will, so this is just system default.
'';
};
# TODO: perhaps options for more common stuff like cache size or forwarding
};
###### implementation
config = mkIf cfg.enable {
environment.etc."knot-resolver/kresd.conf".source = configFile; # not required
users.users.knot-resolver =
{ isSystemUser = true;
group = "knot-resolver";
description = "Knot-resolver daemon user";
};
users.groups.knot-resolver.gid = null;
systemd.packages = [ package ]; # the units are patched inside the package a bit
systemd.targets.kresd = { # configure units started by default
wantedBy = [ "multi-user.target" ];
wants = [ "kres-cache-gc.service" ]
++ map (i: "kresd@${toString i}.service") (range 1 cfg.instances);
};
systemd.services."kresd@".serviceConfig = {
ExecStart = "${package}/bin/kresd --noninteractive "
+ "-c ${package}/lib/knot-resolver/distro-preconfig.lua -c ${configFile}";
# Ensure /run/knot-resolver exists
RuntimeDirectory = "knot-resolver";
RuntimeDirectoryMode = "0770";
# Ensure /var/lib/knot-resolver exists
StateDirectory = "knot-resolver";
StateDirectoryMode = "0770";
# Ensure /var/cache/knot-resolver exists
CacheDirectory = "knot-resolver";
CacheDirectoryMode = "0770";
};
# Try cleaning up the previously default location of cache file.
# Note that /var/cache/* should always be safe to remove.
# TODO: remove later, probably between 20.09 and 21.03
systemd.tmpfiles.rules = [ "R /var/cache/kresd" ];
};
}
|