Generate IPv6 address from IPv6 prefix and interface's MAC address

!README.md

Generate IPv6 address from IPv6 prefix and interface's MAC address

More or less like what SLAAC is doing, but without relying on the router advertisment.

Installation

pip install netifaces

Usage

python ./generate-ipv6.py "eth0" "2001:db8:abcd"

generate-ipv6.py

import netifaces as ni
import re
import argparse
import ipaddress

def get_mac_address(interface):
    try:
        interface_details = ni.ifaddresses(interface)
        mac_address = interface_details[ni.AF_LINK][0]['addr']
        return mac_address
    except (ValueError, KeyError):
        raise ValueError(f"No MAC address found for interface {interface}")

def mac_to_eui64(mac, ipv6_network):
    # Remove any non-hexadecimal characters from MAC
    mac = re.sub(r'[^0-9a-fA-F]', '', mac)
    mac_bytes = bytes.fromhex(mac)

    # Flip the universal/local bit of the MAC address
    mac_bytes = bytearray(mac_bytes)
    mac_bytes[0] ^= 0b00000010

    # Insert ff:fe in the middle of the MAC to form EUI-64
    eui64 = mac_bytes[:3] + b'\xff\xfe' + mac_bytes[3:]
    eui64 = int.from_bytes(eui64, byteorder='big')

    # Calculate full IPv6 address within the network
    full_ipv6_address = ipaddress.IPv6Address(ipv6_network.network_address + eui64)

    return full_ipv6_address

def main():
    parser = argparse.ArgumentParser(description="Generate an IPv6 address from a network device MAC address and an IPv6 prefix with a network mask.")
    parser.add_argument("interface_name", type=str, help="Network interface name")
    parser.add_argument("ipv6_network", type=str, help="IPv6 network with prefix, e.g., xxxx:xxxx:xxxx::/xx")

    args = parser.parse_args()

    try:
        ipv6_network = ipaddress.IPv6Network(args.ipv6_network, strict=False)
        mac_address = get_mac_address(args.interface_name)
        ipv6_address = mac_to_eui64(mac_address, ipv6_network)
        print(f"Generated IPv6 Address: {ipv6_address} from MAC Address: {mac_address}")
    except ValueError as e:
        print(e)
    except ipaddress.AddressValueError as ave:
        print("Error: Invalid IPv6 network format.")

if __name__ == "__main__":
    main()