Mapping Subnets to VLAN IDs

gistfile1.txt

# attribution of hash goes to Dr. Mange
#  (upper_bound-max_projects) / max_efforts

import argparse
import ipaddress

max_projects = 254
max_efforts = 14
lower_bound = 254
upper_bound = 4094

def _mange_hash(project, effort):
    if int(effort) == 0:
        return project
    else:
        return (project * (max_efforts + 1) + effort) % (upper_bound - lower_bound) + lower_bound


def _mange_inverse_hash(identifier):
    project = ((identifier - lower_bound) // (max_efforts + 1))
    effort = ((identifier - lower_bound) % (max_efforts + 1))
    address = "10." + str(project) + "." + str(effort) + ".0"
    return address


def _test():
    hashmap = {}
    for project in list(range(0, max_projects + 1, 1)):
        for effort in list(range(0, max_efforts + 1, 1)):
            vlan_id = _mange_hash(project, effort)

            if vlan_id in hashmap.keys():
                print("colision with project: " + str(project) + " and effort: " + str(effort))
            else:
                hashmap[vlan_id] = [project, effort]


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='A Hash Map of Sub-Networks to VLAN IDs')
    parser.add_argument('-a', '--addr',  default=None, type=str, help='an address in the form of 10.X.Y.0')
    parser.add_argument("-i", '--id', default=None, type=int, help='a VLAN ID in the form of an integer [1-4096]')
    parser.add_argument('-t', '--test', default=None, type=bool, help='test with the fixed parameters for collision')
    args = parser.parse_args()

    if args.addr == args.id == args.test == None:
        print("Need and ID or IP.")
        exit(1)

    if args.addr:
        try:
            address = ipaddress.ip_address(args.addr)
            if address.is_private:
                project, effort = address.exploded.split('.')[1:3]
                if int(effort) <= max_efforts:
                    print(_mange_hash(int(project), int(effort)))
                else:
                    print("Maximum of x.x.14.0")
            else:
                print('Not RFC1918 Class A')
        except ValueError as error:
            print(error)

    if args.id:
        print(_mange_inverse_hash(args.id))

    if args.test:
        _test()