A simple script to generate a seeded ip+port from any string (generally a route for a docker container, useful for plumbing)

hash2addr.sh

#!/bin/bash

# Display help message
if [[ "$1" == "-h" || "$1" == "--help" ]]; then
    echo "usage: $(basename $0) <input_string>"
    echo "Outputs a randomly generated IP address and port number based on the MD5 hash of the input string."
    echo ""
    exit 0
fi

# Check that input string is provided
if [ -z "$1" ]; then
    echo "error: input string not provided."
    echo "usage: $(basename $0) <input_string>"
    echo ""
    exit 1
fi

input_str="$1"

# Hash the input string using MD5 and extract the first 4 bytes
hash_bytes="$(echo -n $input_str | md5sum | cut -d' ' -f1 | head -c 8)"

# Create an IP address in the 127.0.0.0/8 range using the first 3 bytes of the hash
ip="127.$(printf '%d.%d.%d' 0x${hash_bytes:0:2} 0x${hash_bytes:2:2} 0x${hash_bytes:4:2})"

# Use the last 2 bytes of the hash to generate a port number in the range 1024-65535
port="$((0x${hash_bytes:6:2} % (65535 - 1024) + 1024))"

echo "$ip:$port"