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-rw-r--r--nixos/modules/services/networking/ndppd.nix189
1 files changed, 189 insertions, 0 deletions
diff --git a/nixos/modules/services/networking/ndppd.nix b/nixos/modules/services/networking/ndppd.nix
new file mode 100644
index 00000000000..6046ac860cf
--- /dev/null
+++ b/nixos/modules/services/networking/ndppd.nix
@@ -0,0 +1,189 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.ndppd;
+
+  render = s: f: concatStringsSep "\n" (mapAttrsToList f s);
+  prefer = a: b: if a != null then a else b;
+
+  ndppdConf = prefer cfg.configFile (pkgs.writeText "ndppd.conf" ''
+    route-ttl ${toString cfg.routeTTL}
+    ${render cfg.proxies (proxyInterfaceName: proxy: ''
+    proxy ${prefer proxy.interface proxyInterfaceName} {
+      router ${boolToString proxy.router}
+      timeout ${toString proxy.timeout}
+      ttl ${toString proxy.ttl}
+      ${render proxy.rules (ruleNetworkName: rule: ''
+      rule ${prefer rule.network ruleNetworkName} {
+        ${rule.method}${if rule.method == "iface" then " ${rule.interface}" else ""}
+      }'')}
+    }'')}
+  '');
+
+  proxy = types.submodule {
+    options = {
+      interface = mkOption {
+        type = types.nullOr types.str;
+        description = ''
+          Listen for any Neighbor Solicitation messages on this interface,
+          and respond to them according to a set of rules.
+          Defaults to the name of the attrset.
+        '';
+        default = null;
+      };
+      router = mkOption {
+        type = types.bool;
+        description = ''
+          Turns on or off the router flag for Neighbor Advertisement Messages.
+        '';
+        default = true;
+      };
+      timeout = mkOption {
+        type = types.int;
+        description = ''
+          Controls how long to wait for a Neighbor Advertisment Message before
+          invalidating the entry, in milliseconds.
+        '';
+        default = 500;
+      };
+      ttl = mkOption {
+        type = types.int;
+        description = ''
+          Controls how long a valid or invalid entry remains in the cache, in
+          milliseconds.
+        '';
+        default = 30000;
+      };
+      rules = mkOption {
+        type = types.attrsOf rule;
+        description = ''
+          This is a rule that the target address is to match against. If no netmask
+          is provided, /128 is assumed. You may have several rule sections, and the
+          addresses may or may not overlap.
+        '';
+        default = {};
+      };
+    };
+  };
+
+  rule = types.submodule {
+    options = {
+      network = mkOption {
+        type = types.nullOr types.str;
+        description = ''
+          This is the target address is to match against. If no netmask
+          is provided, /128 is assumed. The addresses of serveral rules
+          may or may not overlap.
+          Defaults to the name of the attrset.
+        '';
+        default = null;
+      };
+      method = mkOption {
+        type = types.enum [ "static" "iface" "auto" ];
+        description = ''
+          static: Immediately answer any Neighbor Solicitation Messages
+            (if they match the IP rule).
+          iface: Forward the Neighbor Solicitation Message through the specified
+            interface and only respond if a matching Neighbor Advertisement
+            Message is received.
+          auto: Same as iface, but instead of manually specifying the outgoing
+            interface, check for a matching route in /proc/net/ipv6_route.
+        '';
+        default = "auto";
+      };
+      interface = mkOption {
+        type = types.nullOr types.str;
+        description = "Interface to use when method is iface.";
+        default = null;
+      };
+    };
+  };
+
+in {
+  options.services.ndppd = {
+    enable = mkEnableOption "daemon that proxies NDP (Neighbor Discovery Protocol) messages between interfaces";
+    interface = mkOption {
+      type = types.nullOr types.str;
+      description = ''
+        Interface which is on link-level with router.
+        (Legacy option, use services.ndppd.proxies.<interface>.rules.<network> instead)
+      '';
+      default = null;
+      example = "eth0";
+    };
+    network = mkOption {
+      type = types.nullOr types.str;
+      description = ''
+        Network that we proxy.
+        (Legacy option, use services.ndppd.proxies.<interface>.rules.<network> instead)
+      '';
+      default = null;
+      example = "1111::/64";
+    };
+    configFile = mkOption {
+      type = types.nullOr types.path;
+      description = "Path to configuration file.";
+      default = null;
+    };
+    routeTTL = mkOption {
+      type = types.int;
+      description = ''
+        This tells 'ndppd' how often to reload the route file /proc/net/ipv6_route,
+        in milliseconds.
+      '';
+      default = 30000;
+    };
+    proxies = mkOption {
+      type = types.attrsOf proxy;
+      description = ''
+        This sets up a listener, that will listen for any Neighbor Solicitation
+        messages, and respond to them according to a set of rules.
+      '';
+      default = {};
+      example = literalExpression ''
+        {
+          eth0.rules."1111::/64" = {};
+        }
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    warnings = mkIf (cfg.interface != null && cfg.network != null) [ ''
+      The options services.ndppd.interface and services.ndppd.network will probably be removed soon,
+      please use services.ndppd.proxies.<interface>.rules.<network> instead.
+    '' ];
+
+    services.ndppd.proxies = mkIf (cfg.interface != null && cfg.network != null) {
+      ${cfg.interface}.rules.${cfg.network} = {};
+    };
+
+    systemd.services.ndppd = {
+      description = "NDP Proxy Daemon";
+      documentation = [ "man:ndppd(1)" "man:ndppd.conf(5)" ];
+      after = [ "network-pre.target" ];
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        ExecStart = "${pkgs.ndppd}/bin/ndppd -c ${ndppdConf}";
+
+        # Sandboxing
+        CapabilityBoundingSet = "CAP_NET_RAW CAP_NET_ADMIN";
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        PrivateTmp = true;
+        PrivateDevices = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+        RestrictAddressFamilies = "AF_INET6 AF_PACKET AF_NETLINK";
+        RestrictNamespaces = true;
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+      };
+    };
+  };
+}