IPv4 to IPv4-mapped IPv6 Address Converter

ipv4_to_ipv6_mapped.py

#!/usr/bin/env python3
"""
IPv4 to IPv4-mapped IPv6 Address Converter

Converts standard IPv4 addresses to the ::ffff: IPv6 mapped format.
"""

import ipaddress
import sys


def ipv4_to_mapped_ipv6(ipv4_str: str) -> str:
    """
    Convert an IPv4 address to IPv4-mapped IPv6 format.
    
    Args:
        ipv4_str: IPv4 address as string (e.g., "193.24.210.101")
    
    Returns:
        IPv4-mapped IPv6 address (e.g., "::ffff:c118:d265")
    """
    # Parse and validate the IPv4 address
    ipv4 = ipaddress.IPv4Address(ipv4_str)
    
    # Get the packed bytes (4 bytes)
    octets = ipv4.packed
    
    # Convert to two 16-bit hex groups
    high = (octets[0] << 8) | octets[1]
    low = (octets[2] << 8) | octets[3]
    
    return f"::ffff:{high:x}:{low:x}"


def ipv4_to_mapped_ipv6_url(ipv4_str: str, path: str = "/") -> str:
    """
    Convert an IPv4 address to a full URL with IPv4-mapped IPv6 format.
    
    Args:
        ipv4_str: IPv4 address as string
        path: URL path (default: "/")
    
    Returns:
        Full URL with bracketed IPv6 address
    """
    mapped = ipv4_to_mapped_ipv6(ipv4_str)
    return f"http://[{mapped}]{path}"


def mapped_ipv6_to_ipv4(ipv6_str: str) -> str:
    """
    Convert an IPv4-mapped IPv6 address back to IPv4.
    
    Args:
        ipv6_str: IPv4-mapped IPv6 address (e.g., "::ffff:c118:d265")
    
    Returns:
        IPv4 address as string
    """
    # Remove brackets if present
    ipv6_str = ipv6_str.strip("[]")
    
    # Parse the IPv6 address
    ipv6 = ipaddress.IPv6Address(ipv6_str)
    
    # Check if it's an IPv4-mapped address
    if not ipv6.ipv4_mapped:
        raise ValueError(f"{ipv6_str} is not an IPv4-mapped IPv6 address")
    
    return str(ipv6.ipv4_mapped)


def main():
    print("=" * 50)
    print("IPv4 to IPv4-Mapped IPv6 Converter")
    print("=" * 50)
    
    # Example conversions
    examples = [
        "192.168.1.1",
        "8.8.8.8",
        "10.0.0.1",
        "172.16.0.1",
        "255.255.255.255",
    ]
    
    print("\nExample Conversions:")
    print("-" * 50)
    
    for ipv4 in examples:
        mapped = ipv4_to_mapped_ipv6(ipv4)
        url = ipv4_to_mapped_ipv6_url(ipv4)
        print(f"{ipv4:18} -> {mapped:22} -> {url}")
    
    print("-" * 50)
    
    # Reverse conversion demo
    print("\nReverse Conversion Demo:")
    print("-" * 50)
    test_v6 = "::ffff:c118:d265"
    print(f"{test_v6} -> {mapped_ipv6_to_ipv4(test_v6)}")
    
    # Interactive mode if arguments provided
    if len(sys.argv) > 1:
        print("\n" + "=" * 50)
        print("Your Conversions:")
        print("-" * 50)
        for arg in sys.argv[1:]:
            try:
                # Try IPv4 -> IPv6
                mapped = ipv4_to_mapped_ipv6(arg)
                url = ipv4_to_mapped_ipv6_url(arg)
                print(f"{arg} -> {mapped}")
                print(f"  URL: {url}")
            except ipaddress.AddressValueError:
                try:
                    # Try IPv6 -> IPv4
                    ipv4 = mapped_ipv6_to_ipv4(arg)
                    print(f"{arg} -> {ipv4}")
                except (ipaddress.AddressValueError, ValueError) as e:
                    print(f"Error: {e}")


if __name__ == "__main__":
    main()