uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

nixos/modules/services/networking/babeld.nix

@@ -0,0 +1,144 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.services.babeld;
+
+  conditionalBoolToString = value: if (isBool value) then (boolToString value) else (toString value);
+
+  paramsString = params:
+    concatMapStringsSep " " (name: "${name} ${conditionalBoolToString (getAttr name params)}")
+                   (attrNames params);
+
+  interfaceConfig = name:
+    let
+      interface = getAttr name cfg.interfaces;
+    in
+    "interface ${name} ${paramsString interface}\n";
+
+  configFile = with cfg; pkgs.writeText "babeld.conf" (
+    ''
+      skip-kernel-setup true
+    ''
+    + (optionalString (cfg.interfaceDefaults != null) ''
+      default ${paramsString cfg.interfaceDefaults}
+    '')
+    + (concatMapStrings interfaceConfig (attrNames cfg.interfaces))
+    + extraConfig);
+
+in
+
+{
+
+  meta.maintainers = with maintainers; [ hexa ];
+
+  ###### interface
+
+  options = {
+
+    services.babeld = {
+
+      enable = mkEnableOption "the babeld network routing daemon";
+
+      interfaceDefaults = mkOption {
+        default = null;
+        description = ''
+          A set describing default parameters for babeld interfaces.
+          See <citerefentry><refentrytitle>babeld</refentrytitle><manvolnum>8</manvolnum></citerefentry> for options.
+        '';
+        type = types.nullOr (types.attrsOf types.unspecified);
+        example =
+          {
+            type = "tunnel";
+            split-horizon = true;
+          };
+      };
+
+      interfaces = mkOption {
+        default = {};
+        description = ''
+          A set describing babeld interfaces.
+          See <citerefentry><refentrytitle>babeld</refentrytitle><manvolnum>8</manvolnum></citerefentry> for options.
+        '';
+        type = types.attrsOf (types.attrsOf types.unspecified);
+        example =
+          { enp0s2 =
+            { type = "wired";
+              hello-interval = 5;
+              split-horizon = "auto";
+            };
+          };
+      };
+
+      extraConfig = mkOption {
+        default = "";
+        type = types.lines;
+        description = ''
+          Options that will be copied to babeld.conf.
+          See <citerefentry><refentrytitle>babeld</refentrytitle><manvolnum>8</manvolnum></citerefentry> for details.
+        '';
+      };
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf config.services.babeld.enable {
+
+    boot.kernel.sysctl = {
+      "net.ipv6.conf.all.forwarding" = 1;
+      "net.ipv6.conf.all.accept_redirects" = 0;
+      "net.ipv4.conf.all.forwarding" = 1;
+      "net.ipv4.conf.all.rp_filter" = 0;
+    } // lib.mapAttrs' (ifname: _: lib.nameValuePair "net.ipv4.conf.${ifname}.rp_filter" (lib.mkDefault 0)) config.services.babeld.interfaces;
+
+    systemd.services.babeld = {
+      description = "Babel routing daemon";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        ExecStart = "${pkgs.babeld}/bin/babeld -c ${configFile} -I /run/babeld/babeld.pid -S /var/lib/babeld/state";
+        AmbientCapabilities = [ "CAP_NET_ADMIN" ];
+        CapabilityBoundingSet = [ "CAP_NET_ADMIN" ];
+        DevicePolicy = "closed";
+        DynamicUser = true;
+        IPAddressAllow = [ "fe80::/64" "ff00::/8" "::1/128" "127.0.0.0/8" ];
+        IPAddressDeny = "any";
+        LockPersonality = true;
+        NoNewPrivileges = true;
+        MemoryDenyWriteExecute = true;
+        ProtectSystem = "strict";
+        ProtectClock = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectKernelLogs = true;
+        ProtectControlGroups = true;
+        RestrictAddressFamilies = [ "AF_NETLINK" "AF_INET6" "AF_INET" ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        RemoveIPC = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectProc = "invisible";
+        PrivateMounts = true;
+        PrivateTmp = true;
+        PrivateDevices = true;
+        PrivateUsers = false; # kernel_route(ADD): Operation not permitted
+        ProcSubset = "pid";
+        SystemCallArchitectures = "native";
+        SystemCallFilter = [
+          "@system-service"
+          "~@privileged @resources"
+        ];
+        UMask = "0177";
+        RuntimeDirectory = "babeld";
+        StateDirectory = "babeld";
+      };
+    };
+  };
+}