Find IP address and validate which subnet it is in - bash

Question

We have 3 buildings and I would like to identify the IP that a computer has and then identify which subnet it is in using a series of if/else statements.
For example:
Building 1 = 192.168.1.1 /24
Building 2 = 192.168.2.1 /24
Building 3 = 192.168.3.1 /24
I think I've figured out how to identify the computers IP, now I just need a bit of help figuring out how to change an IP address into a number that can be evaluated. This is what I have so far, but I am missing how to convert the IP somehow.
#!/bin/bash
ip=192.168.1.20
building1min=192.168.1.1
building1max=192.168.1.255
building2min=192.168.2.1
building2max=192.168.2.255
building3min=192.168.3.1
building3max=192.168.3.255
if [ $ip -lt $building1max && $ip -gt $building1min ]{
echo "User is in Building 1"
} else if [ $ip -lt $building2max && $ip -gt $building2min ]
echo "User is in Building 2"
} else if [ $ip -lt $building3max && $ip -gt $building3min ]{
echo "User is in Building 3"
} else {
echo "User is not in any building"
}

Answer 1

The following code should point you in the right direction:
#!/usr/bin/env bash
binary=( {0..1}{0..1}{0..1}{0..1}{0..1}{0..1}{0..1}{0..1} )
convertToBinary() {
local -a oct
local o res ip=$1 mask=$2
IFS=. read -ra oct <<< "$ip"
for o in "${oct[#]}"; do
res+=${binary[o]}
done
printf '%s\n' "${res:0:mask}"
}
isInSubnet() {
local sub=$1 ip=$2
local sub_ip=${sub%/*} sub_mask=${sub#*/}
[[ $(convertToBinary "$sub_ip" "$sub_mask") = "$(convertToBinary "$ip" "$sub_mask")" ]]
}
# USAGE
ip=192.168.2.15
b1=192.168.1.0/24 b2=192.168.2.0/24
if isInSubnet "$b1" "$ip"; then
echo building 1
elif isInSubnet "$b2" "$ip"; then
echo building 2
fi
It first converts the IPs to binary and extracts only the network addresses that are then checked for equality.