From db081fad0e3b3933ca963fae085fd0c5c0764f80 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Tue, 19 Apr 2022 22:03:58 +0200
Subject: First working Wesher configuration

---
 nix/wesher_service.nix | 122 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 nix/wesher_service.nix

(limited to 'nix/wesher_service.nix')

diff --git a/nix/wesher_service.nix b/nix/wesher_service.nix
new file mode 100644
index 0000000..be33a76
--- /dev/null
+++ b/nix/wesher_service.nix
@@ -0,0 +1,122 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+  cfg = config.services.wesher;
+
+in {
+  options = with types; {
+    services.wesher = {
+      enable = mkEnableOption "wesher wireguard overlay mesh network manager";
+
+      package = mkOption {
+        type = package;
+        default = pkgs.wesher;
+        defaultText = literalExpression "pkgs.wesher";
+        description = "Wesher package to use.";
+      };
+
+      clusterKey = mkOption {
+        type = nullOr str;
+        default = null;
+        description = "shared key for cluster membership; must be 32 bytes base64 encoded; will be generated if not provided";
+      };
+
+      bindAddr = mkOption {
+        type = nullOr str;
+        default = null;
+        description = "IP address to bind to for cluster membership (cannot be used with --bind-iface)";
+      };
+
+      bindIface = mkOption {
+        type = nullOr str;
+        default = null;
+        description = "Interface to bind to for cluster membership (cannot be used with --bind-addr)";
+      };
+
+      join = mkOption {
+        type = listOf str;
+        default = [];
+        description = "list of hostnames or IP addresses to existing cluster members; if not provided, will attempt resuming any known state or otherwise wait for further members";
+      };
+
+      clusterPort = mkOption {
+        type = port;
+        default = 7946;
+        description = "port used for membership gossip traffic (both TCP and UDP); must be the same accross cluster";
+      };
+
+      wireguardPort = mkOption {
+        type = port;
+        default = 51820;
+        description = "port used for wireguard traffic (UDP); must be the same accross cluster";
+      };
+
+      overlayNet = mkOption {
+        type = str;
+        default = "10.0.0.0/8";
+        description = "the network in which to allocate addresses for the overlay mesh network (CIDR format); smaller networks increase the chance of IP collision";
+      };
+
+      interface = mkOption {
+        type = str;
+        default = "wgoverlay";
+        description = "name of the wireguard interface to create and manage";
+      };
+
+      logLevel = mkOption {
+        type = str;
+        default = "warn";
+        description = "set the verbosity (one of debug/info/warn/error)";
+      };
+      
+    };
+  };
+
+  config = mkIf cfg.enable (let binWesher = cfg.package + "/bin/wesher";
+  in {
+    systemd.services.wesher = {
+      description = "wesher wireguard overlay mesh network manager";
+      bindsTo = [ "network-online.target" ];
+      after = [ "network-online.target" ];
+      wantedBy = [ "multi-user.target" ];
+
+      environment = {
+        WESHER_JOIN = builtins.concatStringsSep "," cfg.join;
+        WESHER_CLUSTER_PORT = builtins.toString cfg.clusterPort;
+        WESHER_WIREGUARD_PORT = builtins.toString cfg.wireguardPort;
+        WESHER_OVERLAY_NET = cfg.overlayNet;
+        WESHER_INTERFACE = cfg.interface;
+        WESHER_LOG_LEVEL = cfg.logLevel;
+        WESHER_NO_ETC_HOSTS = "true";
+      } 
+      // (if (cfg.clusterKey != null) then { WESHER_CLUSTER_KEY = cfg.clusterKey; } else {})
+      // (if (cfg.bindAddr != null) then { WESHER_BIND_ADDR = cfg.bindAddr; } else {})
+      // (if (cfg.bindIface != null) then { WESHER_BIND_IFACE = cfg.bindIface; } else {})
+      ;
+
+      serviceConfig = {
+        ExecStart = "${binWesher}";
+        Restart = "always";
+
+        User = "wesher";
+        DynamicUser = true;
+        StateDirectory = "wesher";
+
+        AmbientCapabilities = "CAP_NET_ADMIN CAP_NET_BIND_SERVICE";
+        CapabilityBoundingSet = "CAP_NET_ADMIN CAP_NET_BIND_SERVICE";
+        MemoryDenyWriteExecute = true;
+        ProtectControlGroups = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        RestrictAddressFamilies = "AF_UNIX AF_INET AF_INET6 AF_NETLINK";
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        SystemCallArchitectures = "native";
+        SystemCallFilter = "~@clock @cpu-emulation @debug @keyring @module @mount @obsolete @raw-io @resources";
+      };
+    };
+
+    networking.firewall.allowedUDPPorts = mkIf cfg.enable [ cfg.clusterPort cfg.wireguardPort ];
+    networking.firewall.allowedTCPPorts = mkIf cfg.enable [ cfg.clusterPort ];
+  });
+}
-- 
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