nixpkgs/nixos/modules/services/networking/openvpn.nix
2021-10-04 12:47:20 +02:00

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{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.openvpn;
inherit (pkgs) openvpn;
makeOpenVPNJob = cfg: name:
let
path = makeBinPath (getAttr "openvpn-${name}" config.systemd.services).path;
upScript = ''
#! /bin/sh
export PATH=${path}
# For convenience in client scripts, extract the remote domain
# name and name server.
for var in ''${!foreign_option_*}; do
x=(''${!var})
if [ "''${x[0]}" = dhcp-option ]; then
if [ "''${x[1]}" = DOMAIN ]; then domain="''${x[2]}"
elif [ "''${x[1]}" = DNS ]; then nameserver="''${x[2]}"
fi
fi
done
${cfg.up}
${optionalString cfg.updateResolvConf
"${pkgs.update-resolv-conf}/libexec/openvpn/update-resolv-conf"}
'';
downScript = ''
#! /bin/sh
export PATH=${path}
${optionalString cfg.updateResolvConf
"${pkgs.update-resolv-conf}/libexec/openvpn/update-resolv-conf"}
${cfg.down}
'';
configFile = pkgs.writeText "openvpn-config-${name}"
''
errors-to-stderr
${optionalString (cfg.up != "" || cfg.down != "" || cfg.updateResolvConf) "script-security 2"}
${cfg.config}
${optionalString (cfg.up != "" || cfg.updateResolvConf)
"up ${pkgs.writeScript "openvpn-${name}-up" upScript}"}
${optionalString (cfg.down != "" || cfg.updateResolvConf)
"down ${pkgs.writeScript "openvpn-${name}-down" downScript}"}
${optionalString (cfg.authUserPass != null)
"auth-user-pass ${pkgs.writeText "openvpn-credentials-${name}" ''
${cfg.authUserPass.username}
${cfg.authUserPass.password}
''}"}
'';
in {
description = "OpenVPN instance ${name}";
wantedBy = optional cfg.autoStart "multi-user.target";
after = [ "network.target" ];
path = [ pkgs.iptables pkgs.iproute2 pkgs.nettools ];
serviceConfig.ExecStart = "@${openvpn}/sbin/openvpn openvpn --suppress-timestamps --config ${configFile}";
serviceConfig.Restart = "always";
serviceConfig.Type = "notify";
};
in
{
imports = [
(mkRemovedOptionModule [ "services" "openvpn" "enable" ] "")
];
###### interface
options = {
services.openvpn.servers = mkOption {
default = {};
example = literalExpression ''
{
server = {
config = '''
# Simplest server configuration: https://community.openvpn.net/openvpn/wiki/StaticKeyMiniHowto
# server :
dev tun
ifconfig 10.8.0.1 10.8.0.2
secret /root/static.key
''';
up = "ip route add ...";
down = "ip route del ...";
};
client = {
config = '''
client
remote vpn.example.org
dev tun
proto tcp-client
port 8080
ca /root/.vpn/ca.crt
cert /root/.vpn/alice.crt
key /root/.vpn/alice.key
''';
up = "echo nameserver $nameserver | ''${pkgs.openresolv}/sbin/resolvconf -m 0 -a $dev";
down = "''${pkgs.openresolv}/sbin/resolvconf -d $dev";
};
}
'';
description = ''
Each attribute of this option defines a systemd service that
runs an OpenVPN instance. These can be OpenVPN servers or
clients. The name of each systemd service is
<literal>openvpn-<replaceable>name</replaceable>.service</literal>,
where <replaceable>name</replaceable> is the corresponding
attribute name.
'';
type = with types; attrsOf (submodule {
options = {
config = mkOption {
type = types.lines;
description = ''
Configuration of this OpenVPN instance. See
<citerefentry><refentrytitle>openvpn</refentrytitle><manvolnum>8</manvolnum></citerefentry>
for details.
To import an external config file, use the following definition:
<literal>config = "config /path/to/config.ovpn"</literal>
'';
};
up = mkOption {
default = "";
type = types.lines;
description = ''
Shell commands executed when the instance is starting.
'';
};
down = mkOption {
default = "";
type = types.lines;
description = ''
Shell commands executed when the instance is shutting down.
'';
};
autoStart = mkOption {
default = true;
type = types.bool;
description = "Whether this OpenVPN instance should be started automatically.";
};
updateResolvConf = mkOption {
default = false;
type = types.bool;
description = ''
Use the script from the update-resolv-conf package to automatically
update resolv.conf with the DNS information provided by openvpn. The
script will be run after the "up" commands and before the "down" commands.
'';
};
authUserPass = mkOption {
default = null;
description = ''
This option can be used to store the username / password credentials
with the "auth-user-pass" authentication method.
WARNING: Using this option will put the credentials WORLD-READABLE in the Nix store!
'';
type = types.nullOr (types.submodule {
options = {
username = mkOption {
description = "The username to store inside the credentials file.";
type = types.str;
};
password = mkOption {
description = "The password to store inside the credentials file.";
type = types.str;
};
};
});
};
};
});
};
};
###### implementation
config = mkIf (cfg.servers != {}) {
systemd.services = listToAttrs (mapAttrsFlatten (name: value: nameValuePair "openvpn-${name}" (makeOpenVPNJob value name)) cfg.servers);
environment.systemPackages = [ openvpn ];
boot.kernelModules = [ "tun" ];
};
}