A requested script for setting jumbo frames on thousands of unknowable interfaces

vi-jumboframe.sh

#!/bin/bash
#===============================================================================
# MIT License
# 
# Copyright (c) 2017 Jeremy Cliff Armstrong
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#===============================================================================

#_opts=`getopt -o t:ab:m:p:h --long threaded:,altbin,bin:,mtu:,prefix:,help -- "$@"`
_opts=`getopt -o ab:m:p:s:h --long altbin,bin:,mtu:,prefix:,help -- "$@"`

if [ $? != 0 ] ; then echo "Failed parsing options." >&2 ; exit 1 ; fi

#echo "$_opts"
eval set -- "$_opts"

_help=0

while true
do
    case "$1" in
        #-t | --threaded )   _THREADS="$2";      shift 2 ;;
        -b | --bin )        _BIN="$2";          shift 2 ;;
        -m | --mtu )        _MTU="$2";          shift 2 ;;
        -p | --prefix )     _PRE="$2";          shift 2 ;;
        -h | --altbin )     _ALTBIN=1;          shift   ;;
        -h | --help )       _help=1;            shift   ;;
        -- ) shift; break ;;
        * ) break ;;
    esac
done

if [[ _help -gt 0 ]]; then
    #    0         1         2         3         4         5         6         7         8
    #    |123456789|123456789|123456789|123456789|123456789|123456789|123456789|123456789|
    echo "vi-jumboframe.sh: Usage"
    echo
    echo "Sets MTU to 9000 on all interfaces beginning with -p/--prefix and found in"
    echo "'/sys/class/net/'."
    echo
    #echo "  -t|--threaded   Enabled threaded mode. Requires the parallel utility. You"
    #echo "                  must specify the number of threads to use (default=off)"
    #echo
    echo "  -a|--altbin     This script normally uses the ifconfig binary to set MTU. On"
    echo "                  systems where ifconfig is not available this flag will"
    echo "                  enable using the ip binary instead."
    echo
    echo "  -b|--bin        The full path to the executable ifconfig binary. Defaults to"
    echo "                  'ifconfig' and relies on the path to find the binary. If"
    echo "                  used with -a/--altbin sets the full path for the ip binary."
    echo
    echo "  -m|--mtu        The MTU to set each interface to. Defaults to 9000."
    echo
    echo "  -p|--prefix     Limits affected interfaces to those beginning with provided"
    echo "                  prefix. Defaults to 'kvm'."
    echo
    echo "  -h|--help       Display this message and exit."
    echo
    echo "------------------------------------------------------------------------------"
    echo
    echo "Examples:"
    echo
    echo "  unthreaded, use alternate binary, binary located at '/usr/sbin/ip'"
    echo
    echo "      vi-jumboframe.sh -a -b /usr/sbin/ip"
    echo
    #echo "  4 threads, interface prefix 'virt'"
    #echo
    #echo "      vi-jumboframe.sh -t 4 -p virt"
    #echo
    #echo "  16 threads, binary located at '/sbin/ifconfig'"
    #echo
    #echo "      vi-jumboframe.sh -t 16 -b /usr/sbin/ifconfig"
    #echo
    echo "Exit Codes:"
    echo
    echo "  0: Success."
    echo "  1: Failed - no changes were made."
    echo "  2: Failed - Changes may have been made, potentially inconsistent state."
    echo
    exit 0
fi

if [ -z ${_ALTBIN:+x}  ]; then _ALTBIN=0; fi
#if [ -z ${_THREADS:+x} ]; then _THREADS=0; fi
if [ -z ${_MTU:+x}     ]; then _MTU=9000; fi
if [ -z ${_PRE:+x}     ]; then _PRE=kvm; fi
if [ -z ${_BIN:+x}     ]; then
    if [[ ${_ALTBIN} -le 0 ]]; then _BIN=ifconfig; else _BIN=ip; fi
fi

if ! [[ ${_MTU} =~ ^[0-9]+$ ]]; then echo "$0: The MTU must be given as an integer." >&2; exit 1; fi
#if ! [[ ${_THREADS} =~ ^[0-9]+$ ]]; then echo "$0: The number of threads must be given as an integer." >&2; exit 1; fi

cd /sys/class/net
shopt -s nullglob
__devlist=( ${_PRE}* )

if [[ ${_ALTBIN} -le 0 ]]
then
    
    #if [[ ${_THREADS} -le 0 ]]
    #then
        # Using ifconfig, non-threaded
    
        for __dev in ${__devlist[@]}
        do
            if ! ${_BIN} ${__dev} mtu ${_MTU} >/dev/null; then echo "$0: Failed to set MTU on interface '${__dev}'. Exiting early." >&2; exit 2; fi
        done
        
    #else
    #    # Using ifconfig, threaded (not yet implimented)
    #fi
    
else
    
    #if [[ ${_THREADS} -le 0 ]]
    #then
        # Using ip, non-threaded
    
        for __dev in ${__devlist[@]}
        do
            if ! ${_BIN} link set mtu ${_MTU} dev ${__dev} >/dev/null; then echo "$0: Failed to set MTU on interface '${__dev}'. Exiting early." >&2; exit 2; fi
        done
        
    #else
    #    # Using ip, threaded (not yet implimented)
    #fi
    
fi