nixos-router/tests/ddns.nix

# Dynamic DNS: the router tells its provider about the uplink's address, at
# boot and as soon as the address changes (the timer is set to an hour, so
# only the watcher can explain the second update).
#
#   upstream (ISP: DHCP, a dyndns2 update server) -- router
{ self, pkgs }:
let
  common = import ./common.nix;
in
pkgs.testers.runNixOSTest {
  name = "router-ddns";

  defaults.imports = [ common.tools ];
  interactive.defaults = common.interactiveDefaults;

  nodes = {
    upstream =
      { lib, ... }:
      {
        virtualisation.vlans = [ 1 ];
        networking.useNetworkd = true;
        networking.useDHCP = false;
        networking.firewall.enable = false;
        networking.interfaces.eth1.ipv4.addresses = lib.mkForce [ ];
        systemd.network.networks."10-wan" = {
          matchConfig.Name = "eth1";
          address = [ "203.0.113.1/24" ];
        };
        services.dnsmasq = {
          enable = true;
          settings = {
            interface = "eth1";
            bind-interfaces = true;
            dhcp-range = "203.0.113.100,203.0.113.100,255.255.255.0,1h";
            dhcp-option = [ "option:router,203.0.113.1" ];
          };
        };
        # What a dyndns2 provider answers; the access log is the test's record.
        services.nginx = {
          enable = true;
          virtualHosts.default = {
            default = true;
            locations."/nic/update".return = ''200 "good $arg_myip"'';
          };
        };
      };

    router =
      { lib, ... }:
      {
        imports = [ self.nixosModules.router ];
        virtualisation.vlans = [
          1
          2
        ];
        networking.interfaces.eth1.ipv4.addresses = lib.mkForce [ ];
        networking.interfaces.eth2.ipv4.addresses = lib.mkForce [ ];

        router = {
          enable = true;
          wan.interface = "eth1";
          lans.main = {
            interface = "eth2";
            ipv4.address = "192.168.10.1";
            dhcp.pool = {
              start = "192.168.10.100";
              end = "192.168.10.199";
            };
          };
          dnsProviders.provider = {
            type = "dyndns2";
            server = "203.0.113.1";
            username = "router";
            secretFile = "/run/ddns-secret";
          };
          ddns = {
            enable = true;
            provider = "provider";
            ssl = false;
            domains = [
              "home.example.test"
              "vpn.example.test"
            ];
            interval = "1h";
          };
        };

        # The secret is a file on the router, as the web UI leaves it.
        systemd.tmpfiles.rules = [ "f+ /run/ddns-secret 0600 root root - hunter2" ];
      };
  };

  testScript = ''
    start_all()
    upstream.wait_for_unit("nginx.service")
    router.wait_for_unit("network-online.target")
    router.wait_until_succeeds("ip -4 addr show dev eth1 | grep -q 203.0.113.100")
    router.wait_for_unit("router-ddns-watch.service")

    def updated(addr):
        return f"grep -q 'myip={addr}' /var/log/nginx/access.log"

    with subtest("the first address is published, for every name"):
        upstream.wait_until_succeeds(updated("203.0.113.100"), timeout=90)
        # One request for all names or one each, depending on the provider's answer.
        for name in ("home.example.test", "vpn.example.test"):
            upstream.wait_until_succeeds(f"grep -q '{name}.*myip=203.0.113.100' /var/log/nginx/access.log", timeout=30)
        # The login arrives as basic auth, not in the URL, and the secret stays off the command line.
        router.fail("grep -r hunter2 /etc/ddclient* /nix/store/*ddclient.conf 2>/dev/null")

    with subtest("a new address is published at once, not at the next timer"):
        router.succeed("ip addr add 203.0.113.101/24 dev eth1")
        router.succeed("ip addr del 203.0.113.100/24 dev eth1")
        upstream.wait_until_succeeds(updated("203.0.113.101"), timeout=60)
  '';
}