tinc_pre: avoid infinite loop with EBADFD on network restart

nixos/modules/services/networking/tinc.nix

@@ -169,7 +169,8 @@ in
         serviceConfig = {
           Type = "simple";
           PIDFile = "/run/tinc.${network}.pid";
-          Restart = "on-failure";
+          Restart = "always";
+          RestartSec = "3";
         };
         preStart = ''
           mkdir -p /etc/tinc/${network}/hosts

pkgs/tools/networking/tinc/pre.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchgit, autoreconfHook, texinfo, ncurses, readline, zlib, lzo, openssl }:
+{ stdenv, fetchgit, fetchpatch, autoreconfHook, texinfo, ncurses, readline, zlib, lzo, openssl }:
 
 stdenv.mkDerivation rec {
   name = "tinc-${version}";
@@ -19,6 +19,14 @@ stdenv.mkDerivation rec {
     substituteInPlace configure.ac --replace UNKNOWN ${version}
   '';
 
+  patches = [
+    # Avoid infinite loop with "Error while reading from Linux tun/tap device (tun mode) /dev/net/tun: File descriptor in bad state" on network restart
+    (fetchpatch {
+      url = https://github.com/gsliepen/tinc/compare/acefa66...e4544db.patch;
+      sha256 = "1jz7anqqzk7j96l5ifggc2knp14fmbsjdzfrbncxx0qhb6ihdcvn";
+    })
+  ];
+
   postInstall = ''
     rm $out/bin/tinc-gui
   '';