From 036b5d85b8e5d0e0667851ca1ddd9f189997a257 Mon Sep 17 00:00:00 2001
From: randogoth <kflux@posteo.de>
Date: Sat, 7 Feb 2026 20:03:10 +0200
Subject: [PATCH] Tune NIC offloads for Tailscale exit node

---
 modules/services/tailscale.nix | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/modules/services/tailscale.nix b/modules/services/tailscale.nix
index 4269f74..5664ae4 100644
--- a/modules/services/tailscale.nix
+++ b/modules/services/tailscale.nix
@@ -1,4 +1,4 @@
-{ ... }:
+{ pkgs, ... }:
 {
   services.tailscale.enable = true;
   services.tailscale.port = 41641;
@@ -8,4 +8,19 @@
     "--advertise-exit-node"
     "--hostname=bucur"
   ];
+
+  environment.systemPackages = [ pkgs.ethtool ];
+
+  systemd.services.tailscale-offload-tune = {
+    description = "Disable GRO forwarding for Tailscale exit node performance";
+    after = [ "network-online.target" ];
+    wants = [ "network-online.target" ];
+    serviceConfig = {
+      Type = "oneshot";
+      ExecStart = ''
+        /bin/sh -c '${pkgs.iproute2}/bin/ip -o route get 8.8.8.8 | ${pkgs.coreutils}/bin/cut -f 5 -d " " | xargs -r ${pkgs.ethtool}/bin/ethtool -K rx-udp-gro-forwarding on rx-gro-list off'
+      '';
+    };
+    wantedBy = [ "multi-user.target" ];
+  };
 }