nix/nixos/router.nix

{
  lib,
  # outputs,
  config,
  pkgs,
  ...
}: let
  # NOTE: I could turn this into a cool NixOS module?
  # TODO: review https://francis.begyn.be/blog/nixos-home-router
  # TODO: more recent: https://github.com/ghostbuster91/blogposts/blob/a2374f0039f8cdf4faddeaaa0347661ffc2ec7cf/router2023-part2/main.md
  hostname = "router";
  domain = "h.lyte.dev";
  ip = "192.168.0.1";
  cidr = "${ip}/16";
  netmask = "255.255.0.0"; # see cidr
  dhcp_lease_space = {
    min = "192.168.0.5";
    max = "192.168.0.250";
  };
  interfaces = {
    wan = {
      name = "wan0";
      mac = "00:01:2e:82:73:59";
    };
    lan = {
      name = "lan0";
      mac = "00:01:2e:82:73:5a";
    };
  };
  hosts = {
    dragon = {
      identifier = "dragon";
      host = "dragon";
      ip = "192.168.0.10";
    };
    beefcake = {
      identifier = "beefcake";
      host = "beefcake";
      ip = "192.168.0.9";
    };
  };
  sysctl-entries = {
    "net.ipv4.conf.all.forwarding" = true;
    "net.ipv6.conf.all.forwarding" = true;

    # TODO: may want to disable this once it's working
    # "net.ipv6.conf.all.accept_ra" = 0;
    # "net.ipv6.conf.all.autoconf" = 0;
    # "net.ipv6.conf.all.use_tempaddr" = 0;

    # "net.ipv6.conf.${wan_if}.accept_ra" = 2;
    # "net.ipv6.conf.${wan_if}.autoconf" = 1;
  };
in {
  imports = [
    {
      # hardware
      boot = {
        loader = {
          efi.canTouchEfiVariables = true;
          systemd-boot.enable = true;
        };
        initrd.availableKernelModules = ["xhci_pci"];
        initrd.kernelModules = [];
        kernelModules = ["kvm-intel"];
        extraModulePackages = [];
      };

      nixpkgs.hostPlatform = "x86_64-linux";
      powerManagement.cpuFreqGovernor = "performance";
      hardware.cpu.intel.updateMicrocode = true;
    }
  ];

  boot = {
    kernel = {
      sysctl = sysctl-entries;
    };
  };

  environment = {
    systemPackages = with pkgs; [
      wpa_supplicant
      inetutils
      btop
      htop
      bottom
      dog
    ];
  };

  networking = {
    hostName = hostname;
    domain = domain;
    useDHCP = false;

    extraHosts = ''
            127.0.0.1 localhost
            127.0.0.2 ${hostname}.${domain} ${hostname}
            ${ip} ${hostname}.${domain} ${hostname}

            ::1 localhost ip6-localhost ip6-loopback
            ff02::1 ip6-allnodes
      kkkkk      ff02::2 ip6-allrouters
    '';

    firewall.enable = true;
    firewall.allowedTCPPorts = [
      2201
      22
    ];
  };

  systemd.network = {
    enable = true;
    wait-online.anyInterface = true;
    networks = {
      "30-${interfaces.lan.name}" = {
        matchConfig.MACAddress = "${interfaces.lan.mac}";
        linkConfig.RequiredForOnline = "enslaved";
        networkConfig = {
          ConfigureWithoutCarrier = true;
        };
      };
      "10-${interfaces.wan.name}" = {
        matchConfig.MACAddress = "${interfaces.wan.mac}";
        networkConfig = {
          DHCP = true;
          DNSOverTLS = true;
          DNSSEC = true;
          IPv6PrivacyExtensions = false;
          IPForward = true;
        };
        linkConfig.RequiredForOnline = "routable";
      };
    };
  };

  systemd.services.systemd-networkd-wait-online.enable = lib.mkForce false;

  services.openssh.listenAddresses = [
    {
      addr = "0.0.0.0";
      port = 2201;
    }
    {
      addr = "0.0.0.0";
      port = 22;
    }
    {
      addr = "[::]";
      port = 2201;
    }
    {
      addr = "[::]";
      port = 22;
    }
  ];

  # # services.fail2ban.enable = true;
  # services.radvd = {
  #   enable = false;
  #   # NOTE: this config is just the default arch linux config I think and may
  #   # need tweaking? this is what I had on the arch linux router, though :shrug:
  #   config = ''
  #     interface lo
  #     {
  #     	AdvSendAdvert on;
  #     	MinRtrAdvInterval 3;
  #     	MaxRtrAdvInterval 10;
  #     	AdvDefaultPreference low;
  #     	AdvHomeAgentFlag off;

  #     	prefix 2001:db8:1:0::/64
  #     	{
  #     		AdvOnLink on;
  #     		AdvAutonomous on;
  #     		AdvRouterAddr off;
  #     	};

  #     	prefix 0:0:0:1234::/64
  #     	{
  #     		AdvOnLink on;
  #     		AdvAutonomous on;
  #     		AdvRouterAddr off;
  #     		Base6to4Interface ppp0;
  #     		AdvPreferredLifetime 120;
  #     		AdvValidLifetime 300;
  #     	};

  #     	route 2001:db0:fff::/48
  #     	{
  #     		AdvRoutePreference high;
  #     		AdvRouteLifetime 3600;
  #     	};

  #       RDNSS 2001:db8::1 2001:db8::2
  #       {
  #         AdvRDNSSLifetime 30;
  #       };

  #       DNSSL branch.example.com example.com
  #       {
  #         AdvDNSSLLifetime 30;
  #       };
  #     };
  #   '';
  # };

  # services.resolved = {
  #   enable = false;
  #   extraConfig = ''
  #     [Resolve]
  #     DNSStubListener=no
  #   '';
  # };

  # services.dnsmasq = {
  #   enable = false;
  #   settings = {
  #     # server endpoints
  #     listen-address = "::1,127.0.0.1,${ip}";
  #     port = "53";

  #     # DNS cache entries
  #     cache-size = "10000";

  #     # local domain entries
  #     local = "/lan/";
  #     domain = "lan";
  #     expand-hosts = true;

  #     dhcp-authoritative = true;

  #     conf-file = "/usr/share/dnsmasq/trust-anchors.conf";
  #     dnssec = true;

  #     except-interface = "${wan_if}";
  #     interface = "${lan_if}";

  #     enable-ra = true;

  #     # dhcp-option = "121,${cidr},${ip}";

  #     dhcp-range = [
  #       "lan,${dhcp_lease_space.min},${dhcp_lease_space.max},${netmask},10m"
  #       "tag:${lan_if},::1,constructor:${lan_if},ra-names,12h"
  #     ];

  #     dhcp-host = [
  #       "${hosts.dragon.host},${hosts.dragon.ip},12h"
  #       "${hosts.beefcake.host},${hosts.beefcake.ip},12h"
  #     ];

  #     # may need to go in /etc/hosts (networking.extraHosts), too?
  #     address = [
  #       "/video.lyte.dev/192.168.0.9"
  #       "/git.lyte.dev/192.168.0.9"
  #       "/bw.lyte.dev/192.168.0.9"
  #       "/files.lyte.dev/192.168.0.9"
  #       "/vpn.h.lyte.dev/192.168.0.9"
  #       "/.h.lyte.dev/192.168.0.9"
  #     ];

  #     server = [
  #       "${ip}"
  #       "8.8.8.8"
  #       "8.8.4.4"
  #       "1.1.1.1"
  #       "1.0.0.1"
  #     ];
  #   };
  # };

  # nftables = {
  #   enable = false;
  #   flushRuleset = true;

  #   tables = {
  #     filter = {
  #       family = "inet";
  #       content = ''
  #         chain input {
  #           # type filter hook input priority filter; policy accept;
  #           type filter hook input priority 0;

  #           # anything from loopback interface
  #           iifname "lo" accept

  #           # accept traffic we originated
  #           ct state { established, related } counter accept
  #           ct state invalid counter drop

  #           # ICMP
  #           ip6 nexthdr icmpv6 icmpv6 type { echo-request, nd-neighbor-solicit, nd-neighbor-advert, nd-router-solicit, nd-router-advert, mld-listener-query, destination-unreachable, packet-too-big, time-exceeded, parameter-problem } counter accept
  #           ip protocol icmp icmp type { echo-request, destination-unreachable, router-advertisement, time-exceeded, parameter-problem } counter accept
  #           ip protocol icmpv6 counter accept
  #           ip protocol icmp counter accept
  #           meta l4proto ipv6-icmp counter accept

  #           udp dport dhcpv6-client counter accept

  #           tcp dport { 64022, 22, 53, 67, 25565 } counter accept
  #           udp dport { 64020, 22, 53, 67 } counter accept

  #           # iifname "iot" ip saddr $iot-ip tcp dport { llmnr } counter accept
  #           # iifname "iot" ip saddr $iot-ip udp dport { mdns, llmnr } counter accept
  #           iifname "${lan_if}" tcp dport { llmnr } counter accept
  #           iifname "${lan_if}" udp dport { mdns, llmnr } counter accept

  #           counter drop
  #         }

  #         # allow all outgoing
  #         chain output {
  #           type filter hook output priority 0;
  #           accept
  #         }

  #         chain forward {
  #           type filter hook forward priority 0;
  #           accept
  #         }
  #       '';
  #     };

  #     nat = {
  #       family = "ip";
  #       content = ''
  #         set masq_saddr {
  #         	type ipv4_addr
  #         	flags interval
  #         	elements = { ${cidr} }
  #         }

  #         map map_port_ipport {
  #         	type inet_proto . inet_service : ipv4_addr . inet_service
  #         }

  #         chain prerouting {
  #         	iifname ${lan_if} accept

  #         	type nat hook prerouting priority dstnat + 1; policy accept;
  #         	fib daddr type local dnat ip addr . port to meta l4proto . th dport map @map_port_ipport

  #         	iifname ${wan_if} tcp dport { 22, 80, 443, 25565, 64022 } dnat to ${hosts.beefcake.ip}
  #         	iifname ${wan_if} udp dport { 64020 } dnat to ${hosts.beefcake.ip}

  #         	# iifname ${wan_if} tcp dport { 25565 } dnat to 192.168.0.244
  #         	# iifname ${wan_if} udp dport { 25565 } dnat to 192.168.0.244

  #         	# router
  #         	iifname ${wan_if} tcp dport { 2201 } dnat to ${ip}
  #         }

  #         chain output {
  #         	type nat hook output priority -99; policy accept;
  #         	ip daddr != 127.0.0.0/8 oif "lo" dnat ip addr . port to meta l4proto . th dport map @map_port_ipport
  #         }

  #         chain postrouting {
  #         	type nat hook postrouting priority srcnat + 1; policy accept;
  #         	oifname ${lan_if} masquerade
  #         	ip saddr @masq_saddr masquerade
  #         }
  #       '';
  #     };
  #   };
  # };

  # dhcpcd = {
  #   enable = false;
  #   extraConfig = ''
  #     duid

  #     # No way.... https://github.com/NetworkConfiguration/dhcpcd/issues/36#issuecomment-954777644
  #     # issues caused by guests with oneplus devices
  #     noarp

  #     persistent
  #     vendorclassid

  #     option domain_name_servers, domain_name, domain_search
  #     option classless_static_routes
  #     option interface_mtu
  #     option host_name
  #     #option ntp_servers

  #     require dhcp_server_identifier
  #     slaac private
  #     noipv4ll
  #     noipv6rs

  #     static domain_name_servers=${ip}

  #     interface ${wan_if}
  #     	gateway
  #     	ipv6rs
  #     	iaid 1
  #     	# option rapid_commit
  #     	# ia_na 1
  #     	ia_pd 1 ${lan_if}

  #     interface ${lan_if}
  #     	static ip_address=${cidr}
  #     	static routers=${ip}
  #     	static domain_name_servers=${ip}
  #   '';
  # };
  # };
  # systemd.network = {
  #   enable = false;
  #   networks = {
  #     wan = {
  #       networkConfig = {
  #         DHCP = "yes";
  #       };
  #     };
  #     lan = {
  #       networkConfig = {
  #         DHCP = "yes";
  #       };
  #     };
  #   };
  #   links = {
  #     "10-${wan_if}" = {
  #       enable = true;
  #       matchConfig = {
  #         MACAddress = "00:01:2e:82:73:59";
  #       };
  #       linkConfig = {
  #         Name = wan_if;
  #       };
  #     };
  #     "10-${lan_if}" = {
  #       enable = true;
  #       matchConfig = {
  #         MACAddress = "00:01:2e:82:73:5a";
  #       };
  #       linkConfig = {
  #         Name = lan_if;
  #       };
  #     };
  #   };
  # };

  # services.avahi = {
  #   enable = lib.mkForce false;
  #   reflector = false;
  #   allowInterfaces = [lan_if];
  # };

  system.stateVersion = "24.05";
}