nix-files/hosts/by-name/servo/net.nix

185 lines
7.2 KiB
Nix

{ config, lib, pkgs, ... }:
let
portOpts = with lib; types.submodule {
options = {
visibleTo.ovpn = mkOption {
type = types.bool;
default = false;
};
};
};
in
{
options = with lib; {
sane.ports.ports = mkOption {
# add the `visibleTo.ovpn` option
type = types.attrsOf portOpts;
};
};
config = {
networking.domain = "uninsane.org";
sane.ports.openFirewall = true;
sane.ports.openUpnp = true;
# unless we add interface-specific settings for each VPN, we have to define nameservers globally.
# networking.nameservers = [
# "1.1.1.1"
# "9.9.9.9"
# ];
# services.resolved.extraConfig = ''
# # docs: `man resolved.conf`
# # DNS servers to use via the `wg-ovpns` interface.
# # i hope that from the root ns, these aren't visible.
# DNS=46.227.67.134%wg-ovpns 192.165.9.158%wg-ovpns
# FallbackDNS=1.1.1.1 9.9.9.9
# '';
# OVPN CONFIG (https://www.ovpn.com):
# DOCS: https://nixos.wiki/wiki/WireGuard
# if you `systemctl restart wireguard-wg-ovpns`, make sure to also restart any other services in `NetworkNamespacePath = .../ovpns`.
# TODO: why not create the namespace as a seperate operation (nix config for that?)
networking.wireguard.enable = true;
networking.wireguard.interfaces.wg-ovpns = let
ip = "${pkgs.iproute2}/bin/ip";
in-ns = "${ip} netns exec ovpns";
iptables = "${pkgs.iptables}/bin/iptables";
veth-host-ip = "10.0.1.5";
veth-local-ip = "10.0.1.6";
vpn-ip = "185.157.162.178";
# DNS = 46.227.67.134, 192.165.9.158, 2a07:a880:4601:10f0:cd45::1, 2001:67c:750:1:cafe:cd45::1
vpn-dns = "46.227.67.134";
bridgePort = port: proto: ''
${in-ns} ${iptables} -A PREROUTING -t nat -p ${proto} --dport ${port} -m iprange --dst-range ${vpn-ip} \
-j DNAT --to-destination ${veth-host-ip}
'';
bridgeStatements = lib.foldlAttrs
(acc: port: portCfg: acc ++ (builtins.map (bridgePort port) portCfg.protocol))
[]
config.sane.ports.ports;
in {
privateKeyFile = config.sops.secrets.wg_ovpns_privkey.path;
# wg is active only in this namespace.
# run e.g. ip netns exec ovpns <some command like ping/curl/etc, it'll go through wg>
# sudo ip netns exec ovpns ping www.google.com
interfaceNamespace = "ovpns";
ips = [
"185.157.162.178/32"
];
peers = [
{
publicKey = "SkkEZDCBde22KTs/Hc7FWvDBfdOCQA4YtBEuC3n5KGs=";
endpoint = "185.157.162.10:9930";
# alternatively: use hostname, but that presents bootstrapping issues (e.g. if host net flakes)
# endpoint = "vpn36.prd.amsterdam.ovpn.com:9930";
allowedIPs = [ "0.0.0.0/0" ];
# nixOS says this is important for keeping NATs active
persistentKeepalive = 25;
# re-executes wg this often. docs hint that this might help wg notice DNS/hostname changes.
# so, maybe that helps if we specify endpoint as a domain name
# dynamicEndpointRefreshSeconds = 30;
# when refresh fails, try it again after this period instead.
# TODO: not avail until nixpkgs upgrade
# dynamicEndpointRefreshRestartSeconds = 5;
}
];
preSetup = ''
${ip} netns add ovpns || (test -e /run/netns/ovpns && echo "ovpns already exists")
'';
postShutdown = ''
${in-ns} ip link del ovpns-veth-b || echo "couldn't delete ovpns-veth-b"
${ip} link del ovpns-veth-a || echo "couldn't delete ovpns-veth-a"
${ip} netns delete ovpns || echo "couldn't delete ovpns"
# restore rules/routes
${ip} rule del from ${veth-host-ip} lookup ovpns pref 50 || echo "couldn't delete init -> ovpns rule"
${ip} route del default via ${veth-local-ip} dev ovpns-veth-a proto kernel src ${veth-host-ip} metric 1002 table ovpns || echo "couldn't delete init -> ovpns route"
${ip} rule add from all lookup local pref 0
${ip} rule del from all lookup local pref 100
'';
postSetup = ''
# DOCS:
# - some of this approach is described here: <https://josephmuia.ca/2018-05-16-net-namespaces-veth-nat/>
# - iptables primer: <https://danielmiessler.com/study/iptables/>
# create veth pair
${ip} link add ovpns-veth-a type veth peer name ovpns-veth-b
${ip} addr add ${veth-host-ip}/24 dev ovpns-veth-a
${ip} link set ovpns-veth-a up
# mv veth-b into the ovpns namespace
${ip} link set ovpns-veth-b netns ovpns
${in-ns} ip addr add ${veth-local-ip}/24 dev ovpns-veth-b
${in-ns} ip link set ovpns-veth-b up
# make it so traffic originating from the host side of the veth
# is sent over the veth no matter its destination.
${ip} rule add from ${veth-host-ip} lookup ovpns pref 50
# for traffic originating at the host veth to the WAN, use the veth as our gateway
# not sure if the metric 1002 matters.
${ip} route add default via ${veth-local-ip} dev ovpns-veth-a proto kernel src ${veth-host-ip} metric 1002 table ovpns
# give the default route lower priority
${ip} rule add from all lookup local pref 100
${ip} rule del from all lookup local pref 0
# in order to access DNS in this netns, we need to route it to the VPN's nameservers
# - alternatively, we could fix DNS servers like 1.1.1.1.
${in-ns} ${iptables} -A OUTPUT -t nat -p udp --dport 53 -m iprange --dst-range 127.0.0.53 \
-j DNAT --to-destination ${vpn-dns}:53
'' + (lib.concatStringsSep "\n" bridgeStatements);
};
# create a new routing table that we can use to proxy traffic out of the root namespace
# through the ovpns namespace, and to the WAN via VPN.
networking.iproute2.rttablesExtraConfig = ''
5 ovpns
'';
networking.iproute2.enable = true;
# HURRICANE ELECTRIC CONFIG:
# networking.sits = {
# hurricane = {
# remote = "216.218.226.238";
# local = "192.168.0.5";
# # local = "10.0.0.5";
# # remote = "10.0.0.1";
# # local = "10.0.0.22";
# dev = "eth0";
# ttl = 255;
# };
# };
# networking.interfaces."hurricane".ipv6 = {
# addresses = [
# # mx.uninsane.org (publically routed /64)
# {
# address = "2001:470:b:465::1";
# prefixLength = 128;
# }
# # client addr
# # {
# # address = "2001:470:a:466::2";
# # prefixLength = 64;
# # }
# ];
# routes = [
# {
# address = "::";
# prefixLength = 0;
# # via = "2001:470:a:466::1";
# }
# ];
# };
# # after configuration, we want the hurricane device to look like this:
# # hurricane: flags=209<UP,POINTOPOINT,RUNNING,NOARP> mtu 1480
# # inet6 2001:470:a:450::2 prefixlen 64 scopeid 0x0<global>
# # inet6 fe80::c0a8:16 prefixlen 64 scopeid 0x20<link>
# # sit txqueuelen 1000 (IPv6-in-IPv4)
# # test with:
# # curl --interface hurricane http://[2607:f8b0:400a:80b::2004]
# # ping 2607:f8b0:400a:80b::2004
};
}