#!/bin/sh
set -e

# Configure the MTU for the interface
# See https://github.com/NetworkConfiguration/dhcpcd/issues/67 and https://launchpad.net/bugs/2056194

set_mtu() {
	local mtu="$1" interface="$2"

	if [ "$mtu" -lt 576 ]; then
		echo "MTU $mtu is smaller than 576 which is the minimum for dhcpcd. Ignoring MTU." >&2
		return
	fi

	echo "${mtu}" > "/sys/class/net/${interface}/mtu"
	echo "MTU of ${interface} set to ${mtu}"
}

if ${if_up?} && [ -n "${new_interface_mtu-}" ]; then
	set_mtu "${new_interface_mtu}" "${interface?}"
fi