234 lines
9.8 KiB
Nix
234 lines
9.8 KiB
Nix
{ config, lib, pkgs, ... }:
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let
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portOpts = with lib; types.submodule {
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options = {
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visibleTo.ovpn = mkOption {
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type = types.bool;
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default = false;
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};
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};
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};
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in
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{
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options = with lib; {
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sane.ports.ports = mkOption {
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# add the `visibleTo.ovpn` option
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type = types.attrsOf portOpts;
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};
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};
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config = {
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networking.domain = "uninsane.org";
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sane.ports.openFirewall = true;
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sane.ports.openUpnp = true;
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# view refused packets with: `sudo journalctl -k`
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# networking.firewall.logRefusedPackets = true;
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# The global useDHCP flag is deprecated, therefore explicitly set to false here.
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# Per-interface useDHCP will be mandatory in the future, so this generated config
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# replicates the default behaviour.
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networking.useDHCP = false;
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networking.interfaces.eth0.useDHCP = true;
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# XXX colin: probably don't need this. wlan0 won't be populated unless i touch a value in networking.interfaces.wlan0
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networking.wireless.enable = false;
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# this is needed to forward packets from the VPN to the host
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boot.kernel.sysctl."net.ipv4.ip_forward" = 1;
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# unless we add interface-specific settings for each VPN, we have to define nameservers globally.
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# networking.nameservers = [
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# "1.1.1.1"
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# "9.9.9.9"
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# ];
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# use systemd's stub resolver.
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# /etc/resolv.conf isn't sophisticated enough to use different servers per net namespace (or link).
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# instead, running the stub resolver on a known address in the root ns lets us rewrite packets
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# in the ovnps namespace to use the provider's DNS resolvers.
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# a weakness is we can only query 1 NS at a time (unless we were to clone the packets?)
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# there also seems to be some cache somewhere that's shared between the two namespaces.
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# i think this is a libc thing. might need to leverage proper cgroups to _really_ kill it.
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# - getent ahostsv4 www.google.com
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# - try fix: <https://serverfault.com/questions/765989/connect-to-3rd-party-vpn-server-but-dont-use-it-as-the-default-route/766290#766290>
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services.resolved.enable = true;
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# without DNSSEC:
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# - dig matrix.org => works
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# - curl https://matrix.org => works
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# with default DNSSEC:
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# - dig matrix.org => works
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# - curl https://matrix.org => fails
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# i don't know why. this might somehow be interfering with the DNS run on this device (trust-dns)
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services.resolved.dnssec = "false";
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networking.nameservers = [
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# use systemd-resolved resolver
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# full resolver (which understands /etc/hosts) lives on 127.0.0.53
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# stub resolver (just forwards upstream) lives on 127.0.0.54
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"127.0.0.53"
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];
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# nscd -- the Name Service Caching Daemon -- caches DNS query responses
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# in a way that's unaware of my VPN routing, so routes are frequently poor against
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# services which advertise different IPs based on geolocation.
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# nscd claims to be usable without a cache, but in practice i can't get it to not cache!
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# nsncd is the Name Service NON-Caching Daemon. it's a drop-in that doesn't cache;
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# this is OK on the host -- because systemd-resolved caches. it's probably sub-optimal
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# in the netns and we query upstream DNS more often than needed. hm.
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# TODO: run a separate recursive resolver in each namespace.
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services.nscd.enableNsncd = true;
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# services.resolved.extraConfig = ''
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# # docs: `man resolved.conf`
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# # DNS servers to use via the `wg-ovpns` interface.
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# # i hope that from the root ns, these aren't visible.
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# DNS=46.227.67.134%wg-ovpns 192.165.9.158%wg-ovpns
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# FallbackDNS=1.1.1.1 9.9.9.9
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# '';
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# OVPN CONFIG (https://www.ovpn.com):
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# DOCS: https://nixos.wiki/wiki/WireGuard
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# if you `systemctl restart wireguard-wg-ovpns`, make sure to also restart any other services in `NetworkNamespacePath = .../ovpns`.
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# TODO: why not create the namespace as a seperate operation (nix config for that?)
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networking.wireguard.enable = true;
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networking.wireguard.interfaces.wg-ovpns = let
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ip = "${pkgs.iproute2}/bin/ip";
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in-ns = "${ip} netns exec ovpns";
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iptables = "${pkgs.iptables}/bin/iptables";
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veth-host-ip = "10.0.1.5";
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veth-local-ip = "10.0.1.6";
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vpn-ip = "185.157.162.178";
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# DNS = 46.227.67.134, 192.165.9.158, 2a07:a880:4601:10f0:cd45::1, 2001:67c:750:1:cafe:cd45::1
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vpn-dns = "46.227.67.134";
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bridgePort = port: proto: ''
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${in-ns} ${iptables} -A PREROUTING -t nat -p ${proto} --dport ${port} -m iprange --dst-range ${vpn-ip} \
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-j DNAT --to-destination ${veth-host-ip}
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'';
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bridgeStatements = lib.foldlAttrs
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(acc: port: portCfg: acc ++ (builtins.map (bridgePort port) portCfg.protocol))
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[]
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config.sane.ports.ports;
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in {
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privateKeyFile = config.sops.secrets.wg_ovpns_privkey.path;
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# wg is active only in this namespace.
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# run e.g. ip netns exec ovpns <some command like ping/curl/etc, it'll go through wg>
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# sudo ip netns exec ovpns ping www.google.com
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interfaceNamespace = "ovpns";
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ips = [
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"185.157.162.178/32"
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];
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peers = [
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{
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publicKey = "SkkEZDCBde22KTs/Hc7FWvDBfdOCQA4YtBEuC3n5KGs=";
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endpoint = "185.157.162.10:9930";
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# alternatively: use hostname, but that presents bootstrapping issues (e.g. if host net flakes)
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# endpoint = "vpn36.prd.amsterdam.ovpn.com:9930";
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allowedIPs = [ "0.0.0.0/0" ];
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# nixOS says this is important for keeping NATs active
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persistentKeepalive = 25;
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# re-executes wg this often. docs hint that this might help wg notice DNS/hostname changes.
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# so, maybe that helps if we specify endpoint as a domain name
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# dynamicEndpointRefreshSeconds = 30;
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# when refresh fails, try it again after this period instead.
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# TODO: not avail until nixpkgs upgrade
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# dynamicEndpointRefreshRestartSeconds = 5;
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}
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];
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preSetup = ''
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${ip} netns add ovpns || echo "ovpns already exists"
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'';
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postShutdown = ''
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${in-ns} ip link del ovpns-veth-b || echo "couldn't delete ovpns-veth-b"
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${ip} link del ovpns-veth-a || echo "couldn't delete ovpns-veth-a"
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${ip} netns delete ovpns || echo "couldn't delete ovpns"
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# restore rules/routes
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${ip} rule del from ${veth-host-ip} lookup ovpns pref 50 || echo "couldn't delete init -> ovpns rule"
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${ip} route del default via ${veth-local-ip} dev ovpns-veth-a proto kernel src ${veth-host-ip} metric 1002 table ovpns || echo "couldn't delete init -> ovpns route"
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${ip} rule add from all lookup local pref 0
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${ip} rule del from all lookup local pref 100
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'';
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postSetup = ''
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# DOCS:
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# - some of this approach is described here: <https://josephmuia.ca/2018-05-16-net-namespaces-veth-nat/>
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# - iptables primer: <https://danielmiessler.com/study/iptables/>
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# create veth pair
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${ip} link add ovpns-veth-a type veth peer name ovpns-veth-b
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${ip} addr add ${veth-host-ip}/24 dev ovpns-veth-a
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${ip} link set ovpns-veth-a up
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# mv veth-b into the ovpns namespace
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${ip} link set ovpns-veth-b netns ovpns
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${in-ns} ip addr add ${veth-local-ip}/24 dev ovpns-veth-b
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${in-ns} ip link set ovpns-veth-b up
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# make it so traffic originating from the host side of the veth
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# is sent over the veth no matter its destination.
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${ip} rule add from ${veth-host-ip} lookup ovpns pref 50
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# for traffic originating at the host veth to the WAN, use the veth as our gateway
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# not sure if the metric 1002 matters.
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${ip} route add default via ${veth-local-ip} dev ovpns-veth-a proto kernel src ${veth-host-ip} metric 1002 table ovpns
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# give the default route lower priority
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${ip} rule add from all lookup local pref 100
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${ip} rule del from all lookup local pref 0
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# in order to access DNS in this netns, we need to route it to the VPN's nameservers
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# - alternatively, we could fix DNS servers like 1.1.1.1.
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${in-ns} ${iptables} -A OUTPUT -t nat -p udp --dport 53 -m iprange --dst-range 127.0.0.53 \
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-j DNAT --to-destination ${vpn-dns}:53
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'' + (lib.concatStringsSep "\n" bridgeStatements);
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};
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# create a new routing table that we can use to proxy traffic out of the root namespace
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# through the ovpns namespace, and to the WAN via VPN.
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networking.iproute2.rttablesExtraConfig = ''
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5 ovpns
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'';
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networking.iproute2.enable = true;
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# HURRICANE ELECTRIC CONFIG:
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# networking.sits = {
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# hurricane = {
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# remote = "216.218.226.238";
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# local = "192.168.0.5";
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# # local = "10.0.0.5";
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# # remote = "10.0.0.1";
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# # local = "10.0.0.22";
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# dev = "eth0";
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# ttl = 255;
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# };
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# };
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# networking.interfaces."hurricane".ipv6 = {
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# addresses = [
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# # mx.uninsane.org (publically routed /64)
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# {
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# address = "2001:470:b:465::1";
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# prefixLength = 128;
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# }
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# # client addr
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# # {
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# # address = "2001:470:a:466::2";
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# # prefixLength = 64;
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# # }
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# ];
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# routes = [
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# {
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# address = "::";
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# prefixLength = 0;
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# # via = "2001:470:a:466::1";
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# }
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# ];
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# };
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# # after configuration, we want the hurricane device to look like this:
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# # hurricane: flags=209<UP,POINTOPOINT,RUNNING,NOARP> mtu 1480
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# # inet6 2001:470:a:450::2 prefixlen 64 scopeid 0x0<global>
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# # inet6 fe80::c0a8:16 prefixlen 64 scopeid 0x20<link>
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# # sit txqueuelen 1000 (IPv6-in-IPv4)
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# # test with:
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# # curl --interface hurricane http://[2607:f8b0:400a:80b::2004]
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# # ping 2607:f8b0:400a:80b::2004
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};
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}
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