Fix rx and tx in e100 network driver with ethtool

fix-e100.sh

#!/bin/bash
# Copyright 2017 Jaakko-Heikki Heusala <jheusala@iki.fi>
# MIT License
#
# Use like:
#
#   auto eth0
#   iface eth0 inet dhcp
#       pre-up /usr/local/sbin/fix-e100.sh eth0
#

interface="$1"

if test "$interface"; then
        :
else
        echo "USAGE: $0 ethX" >&2
        exit 1
fi

ethtool='/sbin/ethtool'

if test -x $ethtool; then
        :
else
        echo "ERROR: You need ethtool installed." >&2
        exit 2
fi

values="$(ethtool -g "$interface"|grep -F 'Current hardware settings:' -A 4|grep -E '^(RX|TX):'|sort|awk '{print $2}'|tr '\n' '\t')"
rx="$(echo "$values"|awk '{print $1}')"
tx="$(echo "$values"|awk '{print $2}')"

if test "x$rx" = x256; then
        :
else
        "$ethtool" -G "$interface" rx 256
fi

if test "x$tx" = x256; then
        :
else
        "$ethtool" -G "$interface" tx 256
fi