nixpkgs/nixos/modules/services/networking/jool.nix

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{ config, pkgs, lib, ... }:
let
cfg = config.networking.jool;
jool = config.boot.kernelPackages.jool;
jool-cli = pkgs.jool-cli;
hardening = {
# Run as unprivileged user
User = "jool";
Group = "jool";
DynamicUser = true;
# Restrict filesystem to only read the jool module
TemporaryFileSystem = [ "/" ];
BindReadOnlyPaths = [
builtins.storeDir
"/run/booted-system/kernel-modules"
];
# Give capabilities to load the module and configure it
AmbientCapabilities = [ "CAP_SYS_MODULE" "CAP_NET_ADMIN" ];
RestrictAddressFamilies = [ "AF_NETLINK" ];
# Other restrictions
RestrictNamespaces = [ "net" ];
SystemCallFilter = [ "@system-service" "@module" ];
CapabilityBoundingSet = [ "CAP_SYS_MODULE" "CAP_NET_ADMIN" ];
};
configFormat = pkgs.formats.json {};
# Generate the config file of instance `name`
nat64Conf = name:
configFormat.generate "jool-nat64-${name}.conf"
(cfg.nat64.${name} // { instance = name; });
siitConf = name:
configFormat.generate "jool-siit-${name}.conf"
(cfg.siit.${name} // { instance = name; });
# NAT64 config type
nat64Options = lib.types.submodule {
# The format is plain JSON
freeformType = configFormat.type;
# Some options with a default value
options.framework = lib.mkOption {
type = lib.types.enum [ "netfilter" "iptables" ];
default = "netfilter";
description = lib.mdDoc ''
The framework to use for attaching Jool's translation to the exist
kernel packet processing rules. See the
[documentation](https://nicmx.github.io/Jool/en/intro-jool.html#design)
for the differences between the two options.
'';
};
options.global.pool6 = lib.mkOption {
type = lib.types.strMatching "[[:xdigit:]:]+/[[:digit:]]+"
// { description = "Network prefix in CIDR notation"; };
default = "64:ff9b::/96";
description = lib.mdDoc ''
The prefix used for embedding IPv4 into IPv6 addresses.
Defaults to the well-known NAT64 prefix, defined by
[RFC 6052](https://datatracker.ietf.org/doc/html/rfc6052).
'';
};
};
# SIIT config type
siitOptions = lib.types.submodule {
# The format is, again, plain JSON
freeformType = configFormat.type;
# Some options with a default value
options = { inherit (nat64Options.getSubOptions []) framework; };
};
makeNat64Unit = name: opts: {
"jool-nat64-${name}" = {
description = "Jool, NAT64 setup of instance ${name}";
documentation = [ "https://nicmx.github.io/Jool/en/documentation.html" ];
after = [ "network.target" ];
wantedBy = [ "multi-user.target" ];
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
ExecStartPre = "${pkgs.kmod}/bin/modprobe jool";
ExecStart = "${jool-cli}/bin/jool file handle ${nat64Conf name}";
ExecStop = "${jool-cli}/bin/jool -f ${nat64Conf name} instance remove";
} // hardening;
};
};
makeSiitUnit = name: opts: {
"jool-siit-${name}" = {
description = "Jool, SIIT setup of instance ${name}";
documentation = [ "https://nicmx.github.io/Jool/en/documentation.html" ];
after = [ "network.target" ];
wantedBy = [ "multi-user.target" ];
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
ExecStartPre = "${pkgs.kmod}/bin/modprobe jool_siit";
ExecStart = "${jool-cli}/bin/jool_siit file handle ${siitConf name}";
ExecStop = "${jool-cli}/bin/jool_siit -f ${siitConf name} instance remove";
} // hardening;
};
};
checkNat64 = name: _: ''
printf 'Validating Jool configuration for NAT64 instance "${name}"... '
jool file check ${nat64Conf name}
printf 'Ok.\n'; touch "$out"
'';
checkSiit = name: _: ''
printf 'Validating Jool configuration for SIIT instance "${name}"... '
jool_siit file check ${siitConf name}
printf 'Ok.\n'; touch "$out"
'';
in
{
options = {
networking.jool.enable = lib.mkOption {
type = lib.types.bool;
default = false;
relatedPackages = [ "linuxPackages.jool" "jool-cli" ];
description = lib.mdDoc ''
Whether to enable Jool, an Open Source implementation of IPv4/IPv6
translation on Linux.
Jool can perform stateless IP/ICMP translation (SIIT) or stateful
NAT64, analogous to the IPv4 NAPT. Refer to the upstream
[documentation](https://nicmx.github.io/Jool/en/intro-xlat.html) for
the supported modes of translation and how to configure them.
Enabling this option will install the Jool kernel module and the
command line tools for controlling it.
'';
};
networking.jool.nat64 = lib.mkOption {
type = lib.types.attrsOf nat64Options;
default = { };
example = lib.literalExpression ''
{
default = {
# custom NAT64 prefix
global.pool6 = "2001:db8:64::/96";
# Port forwarding
bib = [
{ # SSH 192.0.2.16 → 2001:db8:a::1
"protocol" = "TCP";
"ipv4 address" = "192.0.2.16#22";
"ipv6 address" = "2001:db8:a::1#22";
}
{ # DNS (TCP) 192.0.2.16 → 2001:db8:a::2
"protocol" = "TCP";
"ipv4 address" = "192.0.2.16#53";
"ipv6 address" = "2001:db8:a::2#53";
}
{ # DNS (UDP) 192.0.2.16 → 2001:db8:a::2
"protocol" = "UDP";
"ipv4 address" = "192.0.2.16#53";
"ipv6 address" = "2001:db8:a::2#53";
}
];
pool4 = [
# Port ranges for dynamic translation
{ protocol = "TCP"; prefix = "192.0.2.16/32"; "port range" = "40001-65535"; }
{ protocol = "UDP"; prefix = "192.0.2.16/32"; "port range" = "40001-65535"; }
{ protocol = "ICMP"; prefix = "192.0.2.16/32"; "port range" = "40001-65535"; }
# Ports for static BIB entries
{ protocol = "TCP"; prefix = "192.0.2.16/32"; "port range" = "22"; }
{ protocol = "UDP"; prefix = "192.0.2.16/32"; "port range" = "53"; }
];
};
}
'';
description = lib.mdDoc ''
Definitions of NAT64 instances of Jool.
See the
[documentation](https://nicmx.github.io/Jool/en/config-atomic.html) for
the available options. Also check out the
[tutorial](https://nicmx.github.io/Jool/en/run-nat64.html) for an
introduction to NAT64 and how to troubleshoot the setup.
The attribute name defines the name of the instance, with the main one
being `default`: this can be accessed from the command line without
specifying the name with `-i`.
::: {.note}
Instances created imperatively from the command line will not interfere
with the NixOS instances, provided the respective `pool4` addresses and
port ranges are not overlapping.
:::
::: {.warning}
Changes to an instance performed via `jool -i <name>` are applied
correctly but will be lost after restarting the respective
`jool-nat64-<name>.service`.
:::
'';
};
networking.jool.siit = lib.mkOption {
type = lib.types.attrsOf siitOptions;
default = { };
example = lib.literalExpression ''
{
default = {
# Maps any IPv4 address x.y.z.t to 2001:db8::x.y.z.t and v.v.
global.pool6 = "2001:db8::/96";
# Explicit address mappings
eamt = [
# 2001:db8:1:: ←→ 192.0.2.0
{ "ipv6 prefix" = "2001:db8:1::/128"; "ipv4 prefix" = "192.0.2.0"; }
# 2001:db8:1::x ←→ 198.51.100.x
{ "ipv6 prefix" = "2001:db8:2::/120"; "ipv4 prefix" = "198.51.100.0/24"; }
];
};
}
'';
description = lib.mdDoc ''
Definitions of SIIT instances of Jool.
See the
[documentation](https://nicmx.github.io/Jool/en/config-atomic.html) for
the available options. Also check out the
[tutorial](https://nicmx.github.io/Jool/en/run-vanilla.html) for an
introduction to SIIT and how to troubleshoot the setup.
The attribute name defines the name of the instance, with the main one
being `default`: this can be accessed from the command line without
specifying the name with `-i`.
::: {.note}
Instances created imperatively from the command line will not interfere
with the NixOS instances, provided the respective EAMT addresses and
port ranges are not overlapping.
:::
::: {.warning}
Changes to an instance performed via `jool -i <name>` are applied
correctly but will be lost after restarting the respective
`jool-siit-<name>.service`.
:::
'';
};
};
config = lib.mkIf cfg.enable {
# Install kernel module and cli tools
boot.extraModulePackages = [ jool ];
environment.systemPackages = [ jool-cli ];
# Install services for each instance
systemd.services = lib.mkMerge
(lib.mapAttrsToList makeNat64Unit cfg.nat64 ++
lib.mapAttrsToList makeSiitUnit cfg.siit);
# Check the configuration of each instance
system.checks = lib.optional (cfg.nat64 != {} || cfg.siit != {})
(pkgs.runCommand "jool-validated"
{
nativeBuildInputs = with pkgs.buildPackages; [ jool-cli ];
preferLocalBuild = true;
}
(lib.concatStrings
(lib.mapAttrsToList checkNat64 cfg.nat64 ++
lib.mapAttrsToList checkSiit cfg.siit)));
};
meta.maintainers = with lib.maintainers; [ rnhmjoj ];
}