nixos/avahi: refactor module, add option extraServiceFiles

Types are now specified for all options.
The fixed uid and gid for the avahi user have been removed
and the user avahi is now in the group avahi.
The the generic opening of the firewall for UDP port 5353 is
now optional, but still defaults to true.

The option `extraServiceFiles` was added to specify avahi
service definitions, which are then placed in `/etc/avahi/services`.
This commit is contained in:
WilliButz 2019-05-22 20:59:34 +02:00
parent c260e9e399
commit 49302dc593
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@ -1,10 +1,8 @@
# Avahi daemon.
{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.avahi;
yesNo = yes : if yes then "yes" else "no";
@ -39,215 +37,245 @@ let
enable-reflector=${yesNo reflector}
${extraConfig}
'';
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.
'';
};
domainName = mkOption {
type = types.str;
default = "local";
description = ''
Domain name for all advertisements.
'';
};
browseDomains = mkOption {
default = [ ];
example = [ "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.
'';
};
allowPointToPoint = mkOption {
default = false;
description= ''
Whether to use POINTTOPOINT interfaces. Might make mDNS unreliable due to usually large
latencies with such links and opens a potential security hole by allowing mDNS access from Internet
connections. Use with care and YMMV!
'';
};
wideArea = mkOption {
default = true;
description = ''Whether to enable wide-area service discovery.'';
};
reflector = mkOption {
default = false;
description = ''Reflect incoming mDNS requests to all allowed network interfaces.'';
};
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.
'';
};
cacheEntriesMax = mkOption {
default = null;
type = types.nullOr types.int;
description = ''
Number of resource records to be cached per interface. Use 0 to
disable caching. Avahi daemon defaults to 4096 if not set.
'';
};
extraConfig = mkOption {
default = "";
type = types.lines;
description = ''
Extra config to append to avahi-daemon.conf.
'';
};
options.services.avahi = {
enable = mkOption {
type = types.bool;
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;
default = config.networking.hostName;
defaultText = literalExample "config.networking.hostName";
description = ''
Host name advertised on the LAN. If not set, avahi will use the value
of <option>config.networking.hostName</option>.
'';
};
domainName = mkOption {
type = types.str;
default = "local";
description = ''
Domain name for all advertisements.
'';
};
browseDomains = mkOption {
type = types.listOf types.str;
default = [ ];
example = [ "0pointer.de" "zeroconf.org" ];
description = ''
List of non-local DNS domains to be browsed.
'';
};
ipv4 = mkOption {
type = types.bool;
default = true;
description = "Whether to use IPv4.";
};
ipv6 = mkOption {
type = types.bool;
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.
'';
};
openFirewall = mkOption {
type = types.bool;
default = true;
description = ''
Whether to open the firewall for UDP port 5353.
'';
};
allowPointToPoint = mkOption {
type = types.bool;
default = false;
description= ''
Whether to use POINTTOPOINT interfaces. Might make mDNS unreliable due to usually large
latencies with such links and opens a potential security hole by allowing mDNS access from Internet
connections.
'';
};
wideArea = mkOption {
type = types.bool;
default = true;
description = "Whether to enable wide-area service discovery.";
};
reflector = mkOption {
type = types.bool;
default = false;
description = "Reflect incoming mDNS requests to all allowed network interfaces.";
};
extraServiceFiles = mkOption {
type = with types; attrsOf (either str path);
default = {};
example = literalExample ''
{
ssh = "''${pkgs.avahi}/etc/avahi/services/ssh.service";
smb = '''
<?xml version="1.0" standalone='no'?><!--*-nxml-*-->
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
<name replace-wildcards="yes">%h</name>
<service>
<type>_smb._tcp</type>
<port>445</port>
</service>
</service-group>
''';
}
'';
description = ''
Specify custom service definitions which are placed in the avahi service directory.
See the <citerefentry><refentrytitle>avahi.service</refentrytitle>
<manvolnum>5</manvolnum></citerefentry> manpage for detailed information.
'';
};
publish = {
enable = mkOption {
type = types.bool;
default = false;
description = "Whether to allow publishing in general.";
};
userServices = mkOption {
type = types.bool;
default = false;
description = "Whether to publish user services. Will set <literal>addresses=true</literal>.";
};
addresses = mkOption {
type = types.bool;
default = false;
description = "Whether to register mDNS address records for all local IP addresses.";
};
hinfo = mkOption {
type = types.bool;
default = false;
description = ''
Whether to register a mDNS HINFO record which contains information about the
local operating system and CPU.
'';
};
workstation = mkOption {
type = types.bool;
default = false;
description = ''
Whether to register a service of type "_workstation._tcp" on the local LAN.
'';
};
domain = mkOption {
type = types.bool;
default = false;
description = "Whether to announce the locally used domain name for browsing by other hosts.";
};
};
nssmdns = mkOption {
type = types.bool;
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.
'';
};
cacheEntriesMax = mkOption {
type = types.nullOr types.int;
default = null;
description = ''
Number of resource records to be cached per interface. Use 0 to
disable caching. Avahi daemon defaults to 4096 if not set.
'';
};
extraConfig = mkOption {
type = types.lines;
default = "";
description = ''
Extra config to append to avahi-daemon.conf.
'';
};
};
###### implementation
config = mkIf cfg.enable {
users.users.avahi = {
description = "avahi-daemon privilege separation user";
home = "/var/empty";
group = "avahi";
isSystemUser = true;
};
services.avahi.hostName = mkDefault config.networking.hostName;
users.users = singleton
{ name = "avahi";
uid = config.ids.uids.avahi;
description = "`avahi-daemon' privilege separation user";
home = "/var/empty";
};
users.groups = singleton
{ name = "avahi";
gid = config.ids.gids.avahi;
};
users.groups.avahi = {};
system.nssModules = optional cfg.nssmdns pkgs.nssmdns;
environment.systemPackages = [ pkgs.avahi ];
systemd.sockets.avahi-daemon =
{ description = "Avahi mDNS/DNS-SD Stack Activation Socket";
listenStreams = [ "/run/avahi-daemon/socket" ];
wantedBy = [ "sockets.target" ];
};
systemd.services.avahi-daemon =
{ description = "Avahi mDNS/DNS-SD Stack";
wantedBy = [ "multi-user.target" ];
requires = [ "avahi-daemon.socket" ];
serviceConfig."NotifyAccess" = "main";
serviceConfig."BusName" = "org.freedesktop.Avahi";
serviceConfig."Type" = "dbus";
path = [ pkgs.coreutils pkgs.avahi ];
preStart = "mkdir -p /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}"
'';
environment.etc = (mapAttrs' (n: v: nameValuePair
"avahi/services/${n}.service"
{ ${if types.path.check v then "source" else "text"} = v; }
) cfg.extraServiceFiles);
systemd.sockets.avahi-daemon = {
description = "Avahi mDNS/DNS-SD Stack Activation Socket";
listenStreams = [ "/run/avahi-daemon/socket" ];
wantedBy = [ "sockets.target" ];
};
systemd.tmpfiles.rules = [ "d /run/avahi-daemon - avahi avahi -" ];
systemd.services.avahi-daemon = {
description = "Avahi mDNS/DNS-SD Stack";
wantedBy = [ "multi-user.target" ];
requires = [ "avahi-daemon.socket" ];
# Make NSS modules visible so that `avahi_nss_support ()' can
# return a sensible value.
environment.LD_LIBRARY_PATH = config.system.nssModules.path;
path = [ pkgs.coreutils pkgs.avahi ];
serviceConfig = {
NotifyAccess = "main";
BusName = "org.freedesktop.Avahi";
Type = "dbus";
ExecStart = "${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 ];
networking.firewall.allowedUDPPorts = mkIf cfg.openFirewall [ 5353 ];
};
}