Bash script for portforwarding using IP Tables. required `whois`, `iptables`

.services

MySQL 3306 172.16.1.6:3306
OpenWRT 7000 172.16.1.7:80

portforwarding.sh

#!/bin/bash 
f_s='.services'

services=()
while IFS= read -r line
do
        s=$(echo $line | awk '{print $1}')
        services[${#services[@]}]="$s"

done < "$f_s"


text_help(){
        echo -e "usage: ./portforwarding [options]"
        echo -e "\t-a [IP Address]\tAdd permission to selected IP"
        echo -e "\t-d\t\tDelete permission"
}

add(){
        n=1
        for service in ${services[@]}; do
                echo -e "[ $n ] $service"
                n=$((n + 1))
        done
        read -p "Please select service number you want to forward for $1? [ 1 ] " num_service

        selected=($(cat $f_s | grep ${services[$num_service-1]}))
        r_ip=($(whois -h bgp.tools $1 | tail -n 1 | awk -F '|' '{print $4}'))

        if [ -n "$r_ip" ]; then 
                iptables -t nat -A PREROUTING -s $1 -p tcp -m tcp -m comment --comment "$1-${selected[0]}" --dport ${selected[1]} -j DNAT --to ${selected[2]}
                echo "$r_ip $1 ${selected[0]}" >> $HOME/.allowed_ips
                echo -e "\nSuccess added $1 with country id $r_id\n\n"
        else 
                echo -e "\nFailed added $1\n\n"
        fi
        exit
}

delete(){

        printf "  ID  \t%2s\t%15s\t%s\n" "Country" "IP Address" "Service"

        did=()
        n=1
        while IFS= read -r line
        do
                tip=($(echo $line))
                did[${#did[@]}]="${tip[1]}-${tip[2]}"
                printf "[%2s ]\t%2s\t%15s\t%s\n" $n ${tip[0]} ${tip[1]} ${tip[2]}
                n=$((n + 1))
        done < $HOME/.allowed_ips

        echo -e "\n\n"
        read -p "Select IP to be deleted? [1] " s_ip
        if [ -z "${did[$s_ip-1]}" ]; then 
                echo -e "\nPlease select correct number.\n\n"
                exit
        fi

        tables=$(iptables -t nat -S | grep ${did[$s_ip-1]} | sed 's/\-A/\-D/')
        eval "iptables -t nat $tables"

        if [ -n "$tables" ]; then 
                ip_del=$(echo "${did[$s_ip-1]}" | awk -F '-' '{print $1" "$2}')
                eval "sed -i '/$ip_del/d' $HOME/.allowed_ips"
                echo -e "\nSuccess Delete \"$ip_del\"\n\n"
        fi
        exit
}

if [ -z "$1" ]; then 
        text_help
fi

while [ -n "$1" ]; do 
        case "${1}" in 
                -a)
                        if [ -z "$2" ]; then text_help;exit; fi
                        add $2;;
                -d)
                        delete;;
                *)
                        text_help;;
        esac
        shift
done