nixpkgs/nixos/modules/services/networking/kresd.nix
2020-01-23 23:22:37 +00:00

166 lines
4.8 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.kresd;
configFile = pkgs.writeText "kresd.conf" ''
${optionalString (cfg.listenDoH != []) "modules.load('http')"}
${cfg.extraConfig};
'';
package = pkgs.knot-resolver.override {
extraFeatures = cfg.listenDoH != [];
};
in {
meta.maintainers = [ maintainers.vcunat /* upstream developer */ ];
imports = [
(mkChangedOptionModule [ "services" "kresd" "interfaces" ] [ "services" "kresd" "listenPlain" ]
(config:
let value = getAttrFromPath [ "services" "kresd" "interfaces" ] config;
in map
(iface: if elem ":" (stringToCharacters iface) then "[${iface}]:53" else "${iface}:53") # Syntax depends on being IPv6 or IPv4.
value
)
)
];
###### 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.
'';
};
listenPlain = mkOption {
type = with types; listOf str;
default = [ "[::1]:53" "127.0.0.1:53" ];
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 7858).
For detailed syntax see ListenStream in man systemd.socket.
'';
};
# 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.users.kresd =
{ uid = config.ids.uids.kresd;
group = "kresd";
description = "Knot-resolver daemon user";
};
users.groups.kresd.gid = config.ids.gids.kresd;
systemd.sockets.kresd = rec {
wantedBy = [ "sockets.target" ];
before = wantedBy;
listenStreams = cfg.listenPlain;
socketConfig = {
ListenDatagram = listenStreams;
FreeBind = true;
FileDescriptorName = "dns";
};
};
systemd.sockets.kresd-tls = mkIf (cfg.listenTLS != []) rec {
wantedBy = [ "sockets.target" ];
before = wantedBy;
partOf = [ "kresd.socket" ];
listenStreams = cfg.listenTLS;
socketConfig = {
FileDescriptorName = "tls";
FreeBind = true;
Service = "kresd.service";
};
};
systemd.sockets.kresd-doh = mkIf (cfg.listenDoH != []) rec {
wantedBy = [ "sockets.target" ];
before = wantedBy;
partOf = [ "kresd.socket" ];
listenStreams = cfg.listenDoH;
socketConfig = {
FileDescriptorName = "doh";
FreeBind = true;
Service = "kresd.service";
};
};
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 and control kresd
};
};
systemd.tmpfiles.rules = [ "d '${cfg.cacheDir}' 0770 kresd kresd - -" ];
systemd.services.kresd = {
description = "Knot-resolver daemon";
serviceConfig = {
User = "kresd";
Type = "notify";
WorkingDirectory = cfg.cacheDir;
Restart = "on-failure";
Sockets = [ "kresd.socket" "kresd-control.socket" ]
++ optional (cfg.listenTLS != []) "kresd-tls.socket";
};
# Trust anchor goes from dns-root-data by default.
script = ''
exec '${package}/bin/kresd' --config '${configFile}' --forks=1
'';
requires = [ "kresd.socket" ];
};
};
}