#!/bin/bash
#
# Module: vyatta-update-arp-params
#
# **** License ****
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# This code was originally developed by Vyatta, Inc.
# Portions created by Vyatta are Copyright (C) 2009 Vyatta, Inc.
# All Rights Reserved.
#
# Author: Mohit Mehta
# Date: February 2009
# Description: Update [ARP (IPv4)|Neighbor (IPV6)] Parameters
#
# **** End License ****
#

#
# subroutines
#

print_usage()
{
    echo "Usage:"
    echo -e "\t$0 syntax-check <type of arp paramter> <value of arp paramter> <ipv4/ipv6>"
    echo -e "\t$0 update <type of arp paramter> <value of arp paramter> <ipv4/ipv6>"
    echo -e "\t$0 delete <type of arp paramter> <ipv4/ipv6>"
}

set_table_thresholds() {
    local ip_type=$1
    local arp_value=$2
    local softmax=$((arp_value / 2));
    local min=$((arp_value / 8));
    sudo sysctl -q net.$ip_type.neigh.default.gc_thresh3=$arp_value
    sudo sysctl -q net.$ip_type.neigh.default.gc_thresh2=$softmax
    sudo sysctl -q net.$ip_type.neigh.default.gc_thresh1=$min
}

syntax_arp_param ()
{
 local arp_type=$1
 local arp_value=$2
 local ip_type=$3

 case "$arp_type" in

     table-size)
        local allowed_values=(1024 2048 4096 8192 16384 32768)
        local i
        for i in ${allowed_values[@]}; do
            if [[ "$i" == "$arp_value" ]]; then
                exit 0
            fi
        done
        echo "Allowed values for ARP table-size - ${allowed_values[*]}"
        exit 1
        ;;

     *)
         echo Invalid arp parameter $arp_type to set
         exit 1
        ;;
 esac
}

update_arp_param ()
{
 local arp_type=$1
 local arp_value=$2
 local ip_type=$3
 case "$arp_type" in

     table-size)
        set_table_thresholds $ip_type $arp_value
        ;;

     *)
         echo Invalid arp parameter $arp_type to update
        ;;
 esac
}

#
# main
#

case "$1" in
    syntax-check)
        if [ $# -ne 4 ]; then
                print_usage
                exit 1
        fi
        syntax_arp_param $2 $3 $4
        ;;

    update)
        if [ $# -ne 4 ]; then
                print_usage
                exit 1
        fi
        update_arp_param $2 $3 $4
        ;;

    *)
        print_usage
        exit 1
        ;;

esac

exit 0

# end of file