nix-config/modules/services/adblock/default.nix

{ config, lib, pkgs, ... }:
let
  wgCfg = config.my.services.wireguard;
  cfg = config.my.services.adblock;
in
{
  options.my.services.adblock = with lib; {
    enable = mkEnableOption "Hosts-based adblock using unbound";

    forwardAddresses = mkOption {
      type = with types; listOf str;
      default = [
        "1.0.0.1@853#cloudflare-dns.com"
        "1.1.1.1@853#cloudflare-dns.com"
      ];
      example = [
        "8.8.4.4"
        "8.8.8.8"
      ];
      description = "Which DNS servers to forward queries to";
    };

    interfaces = mkOption {
      type = with types; listOf str;
      default = [
        "0.0.0.0"
        "::"
      ];
      example = literalExample ''
        [
          "127.0.0.1"
        ]
      '';
      description = "Which addresses to listen on";
    };
  };

  config = lib.mkIf cfg.enable {
    # Allow wireguard clients to connect to it
    networking.firewall.interfaces."${wgCfg.iface}" = {
      allowedUDPPorts = [ 53 ];
      allowedTCPPorts = [ 53 ];
    };

    services.unbound = {
      enable = true;

      settings = {
        server = {
          access-control = [
            "127.0.0.0/24 allow"
            "${wgCfg.net.v4.subnet}.0/${toString wgCfg.net.v4.mask} allow"
            "${wgCfg.net.v6.subnet}::0/${toString wgCfg.net.v6.mask} allow"
          ];

          interface = cfg.interfaces;

          so-reuseport = true;
          tls-cert-bundle = "/etc/ssl/certs/ca-certificates.crt";
          tls-upstream = true;

          include = "${pkgs.ambroisie.unbound-zones-adblock}/hosts";
        };

        forward-zone = [{
          name = ".";
          forward-addr = cfg.forwardAddresses;
        }];
      };
    };
  };
}