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nixpkgs/nixos/modules/services/networking/kresd.nix
Vladimír Čunát 180213a0ac
nixos/kresd: fix IPv6 scope syntax
The systemd syntax is suprising to me, but I suppose it's worth being
compatible as people might be sharing it with other modules.
Our regexp is lenient on IPv6 address part, so this is actually
backwards compatible (i.e. you can put the scope at either place).
2022-01-05 15:58:27 +01:00

152 lines
5.5 KiB
Nix

{ 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.
# The optional IPv6 scope spec comes *after* port, perhaps surprisingly.
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 = elemAt al 1;
addrSpec = if al_portOnly == null then "'${head al}${elemAt al 2}'" else "{'::', '0.0.0.0'}";
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" (
""
+ concatMapStrings (mkListen "dns") cfg.listenPlain
+ concatMapStrings (mkListen "tls") cfg.listenTLS
+ concatMapStrings (mkListen "doh2") cfg.listenDoH
+ cfg.extraConfig
);
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.
'';
};
package = mkOption {
type = types.package;
description = "
knot-resolver package to use.
";
default = pkgs.knot-resolver;
defaultText = literalExpression "pkgs.knot-resolver";
example = literalExpression "pkgs.knot-resolver.override { extraFeatures = true; }";
};
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/2 (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
networking.resolvconf.useLocalResolver = mkDefault true;
users.users.knot-resolver =
{ isSystemUser = true;
group = "knot-resolver";
description = "Knot-resolver daemon user";
};
users.groups.knot-resolver.gid = null;
systemd.packages = [ cfg.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@${toString i}.service") (range 1 cfg.instances);
};
systemd.services."kresd@".serviceConfig = {
ExecStart = "${cfg.package}/bin/kresd --noninteractive "
+ "-c ${cfg.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";
};
# We don't mind running stop phase from wrong version. It seems less racy.
systemd.services."kresd@".stopIfChanged = false;
};
}