A script to auto enable transport layer offloads to improve UDP throughput for Tailscale

99-tailscale-gro-fix

#!/bin/sh

# Tailscale GRO optimization for OpenWrt
# This script applies ethtool GRO settings on the WAN interface
# to improve Tailscale UDP throughput as exit node or subnet router.
# Works on linux kernel >= 6.2, Tailscale >= 1.54
# See https://tailscale.com/s/ethtool-config-udp-gro

# Check if ethtool exists. If not, exit with an error.
# The path /usr/sbin/ethtool is common on OpenWrt.
if [ ! -f /usr/sbin/ethtool ]; then
    logger -t tailscale-gro-fix "ethtool not found. Cannot apply GRO optimizations."
    exit 1
fi

# We only want to run this script when the 'wan' interface comes up.
# The variables ACTION and INTERFACE are provided by the hotplug system.
[ "$ACTION" = "ifup" ] && [ "$INTERFACE" = "wan" ] || exit 0

# The DEVICE variable is the actual network adapter name of the 'wan' interface.
# DHCP usually wan, PPPoE usually pppoe-wan
if [ -n "$DEVICE" ]; then
    logger -t tailscale-gro-fix "Applying Tailscale GRO optimizations for '$DEVICE'."
    # Apply the recommended settings.
    ethtool -K "$DEVICE" rx-udp-gro-forwarding on rx-gro-list off
    if [ $? -eq 0 ]; then
        logger -t tailscale-gro-fix "GRO optimizations applied successfully."
    else
        logger -t tailscale-gro-fix "Failed to apply GRO optimizations to '$DEVICE'."
        exit 1
    fi
fi

exit 0