nixpkgs/nixos/modules/services/networking/avahi-daemon.nix
Thomas Strobel cdd7310a50 nixos avahi-daemon: add new option declarations
Add new option declarations to control what information is published
by the avahi daemon. The default values are chosen to respect the
privacy of the user over the connectivity of the system.
2015-12-21 18:20:35 +01:00

208 lines
5.9 KiB
Nix

# Avahi daemon.
{ config, lib, utils, pkgs, ... }:
with lib;
let
cfg = config.services.avahi;
# We must escape interfaces due to the systemd interpretation
subsystemDevice = interface:
"sys-subsystem-net-devices-${utils.escapeSystemdPath interface}.device";
avahiDaemonConf = with cfg; pkgs.writeText "avahi-daemon.conf" ''
[server]
${# Users can set `networking.hostName' to the empty string, when getting
# a host name from DHCP. In that case, let Avahi take whatever the
# current host name is; setting `host-name' to the empty string in
# `avahi-daemon.conf' would be invalid.
if hostName != ""
then "host-name=${hostName}"
else ""}
browse-domains=${concatStringsSep ", " browseDomains}
use-ipv4=${if ipv4 then "yes" else "no"}
use-ipv6=${if ipv6 then "yes" else "no"}
${optionalString (interfaces!=null) "allow-interfaces=${concatStringsSep "," interfaces}"}
[wide-area]
enable-wide-area=${if wideArea then "yes" else "no"}
[publish]
disable-publishing=${if publish.enable then "no" else "yes"}
disable-user-service-publishing=${if publish.userServices then "no" else "yes"}
publish-addresses=${if publish.userServices || publish.addresses then "yes" else "no"}
publish-hinfo=${if publish.hinfo then "yes" else "no"}
publish-workstation=${if publish.workstation then "yes" else "no"}
publish-domain=${if publish.domain then "yes" else "no"}
'';
in
{
###### interface
options = {
services.avahi = {
enable = mkOption {
default = false;
description = ''
Whether to run the Avahi daemon, which allows Avahi clients
to use Avahi's service discovery facilities and also allows
the local machine to advertise its presence and services
(through the mDNS responder implemented by `avahi-daemon').
'';
};
hostName = mkOption {
type = types.str;
description = ''
Host name advertised on the LAN. If not set, avahi will use the value
of config.networking.hostName.
'';
};
browseDomains = mkOption {
default = [ "0pointer.de" "zeroconf.org" ];
description = ''
List of non-local DNS domains to be browsed.
'';
};
ipv4 = mkOption {
default = true;
description = ''Whether to use IPv4'';
};
ipv6 = mkOption {
default = false;
description = ''Whether to use IPv6'';
};
interfaces = mkOption {
type = types.nullOr (types.listOf types.str);
default = null;
description = ''
List of network interfaces that should be used by the <command>avahi-daemon</command>.
Other interfaces will be ignored. If <literal>null</literal> all local interfaces
except loopback and point-to-point will be used.
'';
};
wideArea = mkOption {
default = true;
description = ''Whether to enable wide-area service discovery.'';
};
publish = {
enable = mkOption {
default = false;
description = ''Whether to allow publishing in general.'';
};
userServices = mkOption {
default = false;
description = ''Whether to publish user services. Will set <literal>addresses=true</literal>.'';
};
addresses = mkOption {
default = false;
description = ''Whether to register mDNS address records for all local IP addresses.'';
};
hinfo = mkOption {
default = false;
description = ''
Whether to register an mDNS HINFO record which contains information about the
local operating system and CPU.
'';
};
workstation = mkOption {
default = false;
description = ''Whether to register a service of type "_workstation._tcp" on the local LAN.'';
};
domain = mkOption {
default = false;
description = ''Whether to announce the locally used domain name for browsing by other hosts.'';
};
};
nssmdns = mkOption {
default = false;
description = ''
Whether to enable the mDNS NSS (Name Service Switch) plug-in.
Enabling it allows applications to resolve names in the `.local'
domain by transparently querying the Avahi daemon.
'';
};
};
};
###### implementation
config = mkIf cfg.enable {
services.avahi.hostName = mkDefault config.networking.hostName;
users.extraUsers = singleton
{ name = "avahi";
uid = config.ids.uids.avahi;
description = "`avahi-daemon' privilege separation user";
home = "/var/empty";
};
users.extraGroups = singleton
{ name = "avahi";
gid = config.ids.gids.avahi;
};
system.nssModules = optional cfg.nssmdns pkgs.nssmdns;
environment.systemPackages = [ pkgs.avahi ];
systemd.services.avahi-daemon =
let
deps = optionals (cfg.interfaces!=null) (map subsystemDevice cfg.interfaces);
in
{ description = "Avahi daemon";
wantedBy = [ "ip-up.target" ];
bindsTo = deps;
after = deps;
before = [ "ip-up.target" ];
# Receive restart event after resume
partOf = [ "post-resume.target" ];
path = [ pkgs.coreutils pkgs.avahi ];
preStart = "mkdir -p /var/run/avahi-daemon";
script =
''
# Make NSS modules visible so that `avahi_nss_support ()' can
# return a sensible value.
export LD_LIBRARY_PATH="${config.system.nssModules.path}"
exec ${pkgs.avahi}/sbin/avahi-daemon --syslog -f "${avahiDaemonConf}"
'';
};
services.dbus.enable = true;
services.dbus.packages = [ pkgs.avahi ];
# Enabling Avahi without exposing it in the firewall doesn't make
# sense.
networking.firewall.allowedUDPPorts = [ 5353 ];
};
}