liminix

router-with-l2tp.nix (6891B)

---

 # A demonstration config for a home/soho router with PPPoE upstream
 # and fallback to an L2TP tunnel over a USB WWAN device
 
 {
   config,
   pkgs,
   lib,
   ...
 }:
 let
   secrets = import ./extneder-secrets.nix;
   rsecrets = import ./rotuer-secrets.nix;
 
   # https://support.aa.net.uk/Category:Incoming_L2TP says:
   # "Please use the DNS name (l2tp.aa.net.uk) instead of hardcoding an
   # IP address; IP addresses can and do change. If you have to use an
   # IP, use 194.4.172.12, but do check the DNS for l2tp.aa.net.uk in
   # case it changes."
 
   # but (1) we don't want to use the wwan stick's dns as our main
   # resolver: it's provided by some mobile ISP and they aren't
   # necessarily the best at providing unfettered services without
   # deciding to do something weird; (2) it's not simple to arrange
   # that xl2tpd gets a different resolver than every other process;
   # (3) there's no way to specify an lns address to xl2tpd at runtime
   # except by rewriting its config file. So what we will do is lookup
   # the lns hostname using the mobile ISP's dns server and then refuse
   # to start l2tp unless the expected lns address is one of the
   # addresses returned. I think this satisfies "do check the DNS"
 
   lns = {
     hostname = "l2tp.aaisp.net.uk";
     address = "194.4.172.12";
   };
 
   inherit (pkgs.liminix.services) oneshot longrun target;
   inherit (pkgs.liminix) outputRef;
   inherit (pkgs.pseudofile) dir symlink;
   inherit (pkgs) serviceFns;
   svc = config.system.service;
   wirelessConfig = {
     country_code = "GB";
     inherit (rsecrets) wpa_passphrase;
     wmm_enabled = 1;
   };
 in
 rec {
   boot = {
     tftp = {
       serverip = "10.0.0.1";
       ipaddr = "10.0.0.8";
     };
   };
 
   imports = [
     ../modules/wwan
     ../modules/network
     ../modules/ssh
     ../modules/usb.nix
     ../modules/ppp
     ../modules/round-robin
     ../modules/health-check
     ../modules/secrets
     ../modules/profiles/gateway.nix
   ];
   hostname = "thing";
 
   services.wan-address-for-secrets = svc.network.address.build {
     interface = config.hardware.networkInterfaces.wan;
     family = "inet";
     address = "10.0.0.10";
     prefixLength = 24;
   };
 
   services.secrets = svc.secrets.outboard.build {
     name = "secret-service";
     url = "http://10.0.0.1/liminix/examples/real-secrets.json";
     username = "demo";
     password = "demo";
     interval = 5;
     dependencies = [ services.wan-address-for-secrets ];
   };
 
   services.wwan = svc.wwan.huawei-e3372.build {
     apn = "data.uk";
     username = "user";
     password = "one2one";
     authType = "chap";
   };
 
   profile.gateway = {
     lan = {
       interfaces = with config.hardware.networkInterfaces; [
         # EDIT: these are the interfaces exposed by the gl.inet gl-ar750:
         # if your device has more or differently named lan interfaces,
         # specify them here
         wlan
         wlan5
         lan
       ];
       inherit (rsecrets.lan) prefix;
       address = {
         family = "inet";
         address = "${rsecrets.lan.prefix}.1";
         prefixLength = 24;
       };
       dhcp = {
         start = 10;
         end = 240;
         hosts =
           { }
           // lib.optionalAttrs (builtins.pathExists ./static-leases.nix) (import ./static-leases.nix);
         localDomain = "lan";
       };
     };
     wan =
       let
         secret = outputRef config.services.secrets;
         username = secret "ppp/username";
         password = secret "ppp/password";
       in
       {
         interface =
           let
             pppoe = svc.pppoe.build {
               interface = config.hardware.networkInterfaces.wan;
               debug = true;
               inherit username password;
             };
 
             l2tp =
               let
                 check-address = oneshot rec {
                   name = "check-lns-address";
                   up = "grep -Fx ${lns.address} $(output_path ${services.lns-address} addresses)";
                   dependencies = [ services.lns-address ];
                 };
                 route = svc.network.route.build {
                   via = "$(output ${services.bootstrap-dhcpc} router)";
                   target = lns.address;
                   dependencies = [
                     services.bootstrap-dhcpc
                     check-address
                   ];
                 };
                 l2tpd = svc.l2tp.build {
                   lns = lns.address;
                   inherit username password;
                   dependencies = [
                     config.services.lns-address
                     route
                     check-address
                   ];
                 };
               in
               svc.health-check.build {
                 service = l2tpd;
                 threshold = 3;
                 interval = 2;
                 healthCheck = pkgs.writeAshScript "ping-check" { } "ping 1.1.1.1";
               };
           in
           svc.round-robin.build {
             name = "wan";
             services = [
               pppoe
               l2tp
             ];
           };
         dhcp6.enable = true;
       };
 
     wireless.networks = {
       "${rsecrets.ssid}" =
         {
           interface = config.hardware.networkInterfaces.wlan;
           hw_mode = "g";
           channel = "6";
           ieee80211n = 1;
         }
         // wirelessConfig
         // {
           wpa_passphrase = outputRef config.services.secrets "wpa_passphrase";
         };
 
       "${rsecrets.ssid}5" =
         rec {
           interface = config.hardware.networkInterfaces.wlan5;
           hw_mode = "a";
           channel = 36;
           ht_capab = "[HT40+]";
           vht_oper_chwidth = 1;
           vht_oper_centr_freq_seg0_idx = channel + 6;
           ieee80211n = 1;
           ieee80211ac = 1;
         }
         // wirelessConfig
         // {
           wpa_passphrase = outputRef config.services.secrets "wpa_passphrase";
         };
     };
   };
 
   services.bootstrap-dhcpc = svc.network.dhcp.client.build {
     interface = config.services.wwan;
     dependencies = [ config.services.hostname ];
   };
 
   services.sshd = svc.ssh.build {
     authorizedKeys = outputRef config.services.secrets "ssh/authorizedKeys";
   };
 
   services.lns-address =
     let
       ns = "$(output_word ${services.bootstrap-dhcpc} dns 1)";
       route-to-bootstrap-nameserver = svc.network.route.build {
         via = "$(output ${services.bootstrap-dhcpc} router)";
         target = ns;
         dependencies = [ services.bootstrap-dhcpc ];
       };
     in
     oneshot rec {
       name = "resolve-l2tp-server";
       dependencies = [
         services.bootstrap-dhcpc
         route-to-bootstrap-nameserver
       ];
       up = ''
         (in_outputs ${name}
          DNSCACHEIP="${ns}" ${pkgs.s6-dns}/bin/s6-dnsip4 ${lns.hostname} \
           > addresses
         )
       '';
     };
 
   users.root = rsecrets.root;
 
   programs.busybox.options = {
     FEATURE_FANCY_TAIL = "y";
   };
 
 }