From e16074e889c8655c8dcfc74c37d28eac3077bf9a Mon Sep 17 00:00:00 2001
From: Madoura <madouura@gmail.com>
Date: Sat, 1 Jan 2022 17:43:37 -0600
Subject: [PATCH] nixos/tetrd: init

---
 .../from_md/release-notes/rl-2205.section.xml |  8 ++
 .../manual/release-notes/rl-2205.section.md   |  2 +
 nixos/modules/services/networking/tetrd.nix   | 96 +++++++++++++++++++
 3 files changed, 106 insertions(+)
 create mode 100644 nixos/modules/services/networking/tetrd.nix

diff --git a/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml b/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml
index a57fd5186cbc..4b3eea55290e 100644
--- a/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml
+++ b/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml
@@ -81,6 +81,14 @@
           <link xlink:href="options.html#opt-services.maddy.enable">services.maddy</link>.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          <link xlink:href="https://tetrd.app">tetrd</link>, share your
+          internet connection from your device to your PC and vice versa
+          through a USB cable. Available at
+          <link linkend="opt-services.tetrd.enable">services.tetrd</link>.
+        </para>
+      </listitem>
     </itemizedlist>
   </section>
   <section xml:id="sec-release-22.05-incompatibilities">
diff --git a/nixos/doc/manual/release-notes/rl-2205.section.md b/nixos/doc/manual/release-notes/rl-2205.section.md
index 804db667ecfb..b4caca17f720 100644
--- a/nixos/doc/manual/release-notes/rl-2205.section.md
+++ b/nixos/doc/manual/release-notes/rl-2205.section.md
@@ -27,6 +27,8 @@ In addition to numerous new and upgraded packages, this release has the followin
 
 - [maddy](https://maddy.email), a composable all-in-one mail server. Available as [services.maddy](options.html#opt-services.maddy.enable).
 
+- [tetrd](https://tetrd.app), share your internet connection from your device to your PC and vice versa through a USB cable. Available at [services.tetrd](#opt-services.tetrd.enable).
+
 ## Backward Incompatibilities {#sec-release-22.05-incompatibilities}
 
 - `pkgs.ghc` now refers to `pkgs.targetPackages.haskellPackages.ghc`.
diff --git a/nixos/modules/services/networking/tetrd.nix b/nixos/modules/services/networking/tetrd.nix
new file mode 100644
index 000000000000..ead73c497764
--- /dev/null
+++ b/nixos/modules/services/networking/tetrd.nix
@@ -0,0 +1,96 @@
+{ config, lib, pkgs, ... }:
+
+{
+  options.services.tetrd.enable = lib.mkEnableOption pkgs.tetrd.meta.description;
+
+  config = lib.mkIf config.services.tetrd.enable {
+    environment = {
+      systemPackages = [ pkgs.tetrd ];
+      etc."resolv.conf".source = "/etc/tetrd/resolv.conf";
+    };
+
+    systemd = {
+      tmpfiles.rules = [ "f /etc/tetrd/resolv.conf - - -" ];
+
+      services.tetrd = {
+        description = pkgs.tetrd.meta.description;
+        wantedBy = [ "multi-user.target" ];
+
+        serviceConfig = {
+          ExecStart = "${pkgs.tetrd}/opt/Tetrd/bin/tetrd";
+          Restart = "always";
+          RuntimeDirectory = "tetrd";
+          RootDirectory = "/run/tetrd";
+          DynamicUser = true;
+          UMask = "006";
+          DeviceAllow = "usb_device";
+          LockPersonality = true;
+          MemoryDenyWriteExecute = true;
+          NoNewPrivileges = true;
+          PrivateMounts = true;
+          PrivateNetwork = lib.mkDefault false;
+          PrivateTmp = true;
+          PrivateUsers = lib.mkDefault false;
+          ProtectClock = lib.mkDefault false;
+          ProtectControlGroups = true;
+          ProtectHome = true;
+          ProtectHostname = true;
+          ProtectKernelLogs = true;
+          ProtectKernelModules = true;
+          ProtectKernelTunables = true;
+          ProtectProc = "invisible";
+          ProtectSystem = "strict";
+          RemoveIPC = true;
+          RestrictAddressFamilies = [ "AF_UNIX" "AF_INET" "AF_INET6" "AF_NETLINK" ];
+          RestrictNamespaces = true;
+          RestrictRealtime = true;
+          RestrictSUIDSGID = true;
+          SystemCallArchitectures = "native";
+
+          SystemCallFilter = [
+            "@system-service"
+            "~@aio"
+            "~@chown"
+            "~@clock"
+            "~@cpu-emulation"
+            "~@debug"
+            "~@keyring"
+            "~@memlock"
+            "~@module"
+            "~@mount"
+            "~@obsolete"
+            "~@pkey"
+            "~@raw-io"
+            "~@reboot"
+            "~@swap"
+            "~@sync"
+          ];
+
+          BindReadOnlyPaths = [
+            builtins.storeDir
+            "/etc/ssl"
+            "/etc/static/ssl"
+            "${pkgs.nettools}/bin/route:/usr/bin/route"
+            "${pkgs.nettools}/bin/ifconfig:/usr/bin/ifconfig"
+          ];
+
+          BindPaths = [
+            "/etc/tetrd/resolv.conf:/etc/resolv.conf"
+            "/run"
+            "/var/log"
+          ];
+
+          CapabilityBoundingSet = [
+            "CAP_DAC_OVERRIDE"
+            "CAP_NET_ADMIN"
+          ];
+
+          AmbientCapabilities = [
+            "CAP_DAC_OVERRIDE"
+            "CAP_NET_ADMIN"
+          ];
+        };
+      };
+    };
+  };
+}