ethtool-offload

#! /usr/bin/env bash

# For OpenWrt hotplug.d Scripts
if [ -n "$ACTION" ]; then
	if [ "$ACTION" = "add" ] || [ "$ACTION" = "ifup" ]; then
		:
	else
		exit 0
	fi
fi

# Configuration
# Disable LRO and HW-GRO on Routers/Gateways to fix bridge/forwarding issues.
lroDisable=true
rxGroHwDisable=true
# Disable RX-GRO-LIST to improve QUIC/UDP throughput (fixes packet reordering/latency).
rxGroListDisable=true
# Disable TX-NOCACHE-COPY to bypass local cache for direct memory access.
txNocacheCopyDisable=true

# Interface Detection Logic
if [ -n "$DEVICE" ]; then
	TARGET_INTERFACES="$DEVICE"
	echo "[ethtool-offload] Hotplug event detected for: $DEVICE"
elif [ -n "$DEVICENAME" ]; then
	TARGET_INTERFACES="$DEVICENAME"
	echo "[ethtool-offload] Hotplug event detected for: $DEVICENAME"
else
	echo "[ethtool-offload] Manual run mode. Scanning all interfaces..."
	TARGET_INTERFACES="$(ip -o link show | awk -F': ' '{print $2}' | grep -v "lo" | sed 's/@.*$//')"
fi

for i in $TARGET_INTERFACES; do
	# Physical Check
	# We check if the interface has a symlink to a hardware device in sysfs.
	if [ ! -e "/sys/class/net/$i/device" ]; then
		echo "[ethtool-offload] Skipping $i (Virtual Interface)"
		continue
	fi

	# Double check it isn't a virtual device masquerading.
	if readlink -f "/sys/class/net/$i/device" | grep -q "/virtual/"; then
		echo "[ethtool-offload] Skipping $i (Virtual Device Path)"
		continue
	fi

	echo "[ethtool-offload] Applying settings to Physical Interface: $i..."

	# Base Offloads
	ethtool --offload "$i" rx on tx on sg on tso on gso on gro on highdma on rxvlan on txvlan on ntuple on rxhash on rx-udp-gro-forwarding on tx-tcp6-segmentation on tx-gre-segmentation on tx-ipip-segmentation on tx-sit-segmentation on tx-udp_tnl-segmentation on tx-sctp-segmentation on tx-checksum-sctp on esp-hw-offload on esp-tx-csum-hw-offload on tls-hw-tx-offload on tls-hw-rx-offload on l2-fwd-offload on 2>/dev/null

	# Bridge Member Check
	# Detect if interface is part of a bridge (directly or via a bond).
	IS_BRIDGE_MEMBER=false
	MASTER_IF=$(basename $(readlink /sys/class/net/$i/master) 2>/dev/null)

	if [ -n "$MASTER_IF" ]; then
		# Check if a member of a bridge.
		if [ -d "/sys/class/net/$MASTER_IF/bridge" ]; then
			IS_BRIDGE_MEMBER=true
		# Check if a bond slave of a bond which is a member of a bridge.
		elif [ -d "/sys/class/net/$MASTER_IF/bonding" ]; then
			BOND_MASTER=$(basename $(readlink /sys/class/net/$MASTER_IF/master) 2>/dev/null)
			if [ -n "$BOND_MASTER" ] && [ -d "/sys/class/net/$BOND_MASTER/bridge" ]; then
				IS_BRIDGE_MEMBER=true
			fi
		fi
	fi

	# Disable RX-VLAN-Filter dynamically based on bridge status.
	if [ "$IS_BRIDGE_MEMBER" = true ]; then
		echo "[ethtool-offload] Interface $i is a bridge member. Disabling RX-VLAN-Filter..."
		ethtool -K "$i" rx-vlan-filter off 2>/dev/null
	else
		ethtool -K "$i" rx-vlan-filter on 2>/dev/null
	fi

	# Bond Slave Check
	if [ -e "/sys/class/net/$i/master" ] && [ -d "/sys/class/net/$(basename $(readlink /sys/class/net/$i/master))/bonding" ]; then
		echo "[ethtool-offload] Interface $i is a bond slave. Disabling Fraglist, GSO-Partial, and VLAN-Stag offloads..."
		ethtool -K "$i" tx-scatter-gather-fraglist off 2>/dev/null
		ethtool -K "$i" tx-gso-partial off 2>/dev/null
		# Disable VLAN-Stag offloads on bond slaves to prevent conflicts with LACP.
		ethtool -K "$i" tx-vlan-stag-hw-insert off rx-vlan-stag-hw-parse off 2>/dev/null
	else
		ethtool -K "$i" tx-scatter-gather-fraglist on 2>/dev/null
		ethtool -K "$i" tx-gso-partial on 2>/dev/null
		ethtool -K "$i" tx-vlan-stag-hw-insert on rx-vlan-stag-hw-parse on 2>/dev/null
	fi

	if [ "$lroDisable" = true ]; then
		echo "[ethtool-offload] Disabling LRO on $i..."
		echo "[ethtool-offload] See https://serverfault.com/a/806454 for more information."
		ethtool -K "$i" lro off 2>/dev/null
	else
		ethtool -K "$i" lro on 2>/dev/null
	fi

	if [ "$rxGroHwDisable" = true ]; then
		echo "[ethtool-offload] Disabling HW-GRO on $i..."
		ethtool -K "$i" rx-gro-hw off 2>/dev/null
	else
		ethtool -K "$i" rx-gro-hw on 2>/dev/null
	fi

	if [ "$rxGroListDisable" = true ]; then
		echo "[ethtool-offload] Disabling RX-GRO-List on $i..."
		echo "[ethtool-offload] See https://tailscale.com/blog/quic-udp-throughput for more information."
		ethtool -K "$i" rx-gro-list off 2>/dev/null
	else
		ethtool -K "$i" rx-gro-list on 2>/dev/null
	fi

	if [ "$txNocacheCopyDisable" = true ]; then
		echo "[ethtool-offload] Disabling TX-NoCache-Copy on $i..."
		echo "[ethtool-offload] See https://enterprise-support.nvidia.com/s/article/how-to-bypass-local-cache--disable-tx-nocache-copy-x for more information."
		ethtool -K "$i" tx-nocache-copy off 2>/dev/null
	else
		ethtool -K "$i" tx-nocache-copy on 2>/dev/null
	fi
done

exit 0

ethtool-offload.rules

ACTION=="add|bind", SUBSYSTEM=="net", RUN+="/usr/local/sbin/ethtool-offload %k"
ACTION=="change", SUBSYSTEM=="net", ATTR{operstate}=="up", RUN+="/usr/local/sbin/ethtool-offload %k"