generate_license.py

#!/usr/bin/python3

from errno import EINVAL
from sys import argv
from sys import exit
from sys import stdout
from sys import stderr
import getopt
import fcntl, socket, struct

license_magic=b"\xb2\x26\xbc\x27\x4e\x22\x0f\x53"

def get_mac(ifname):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    info = fcntl.ioctl(s.fileno(), 0x8927, struct.pack('256s',
                       bytes(ifname[:15], 'utf-8')))
    return info[18:24]

def license_early_check(path) :
    fd = open(path, "rb")
    fd.seek(0)
    buf = fd.read(8)
    fd.close()
    if buf != license_magic :
        stderr.write("wrong license magic, is it a valid license template?\n")
        exit(1)
    return 0

def usage(argv) :
    stdout.write("usage: %s -t <template_file> -i <interface> [-d YYYY/MM/DD]"
            % argv[0])
    exit(1)

def generate_license_code(mac):
    mac_res = []
    for i in range(0, 16):
        if i < 6:
            mac_res.append(mac[i] + i)
        else:
            mac_res.append(mac[i % 6] + i)
    serial = bytearray(16)
    for i in range(0, 8):
        serial[i] = (mac_res[i] + mac_res[i + 8]) % 256
    license = bytearray(16)
    rd = [162,15,239,202,57,14,45,164,147,232,120,90,117,15,239,232]
    for i in range(0, 16):
        license[i] = (serial[i] + rd[i]) % 256
    return license

def output_licese_file(license_code, template_path):
    fd = open(template_path, 'rb')
    fd.seek(0)
    stdout.buffer.write(fd.read(0x40))
    stdout.buffer.write(bytes(license_code))
    fd.seek(0x50)
    stdout.buffer.write(fd.read(0x50))

if __name__ == "__main__" :
    template_path = ""
    interface_name = ""

    try:
        opts, args = getopt.getopt(argv[1:], "t:i:d:")
    except getopt.GetoptError as err:
        stdout.write("%s\n" % str(err))
        usage(argv)
        exit(1)
    for o, a in opts:
        if o == "-t":
            template_path = a
        if o == "-i":
            interface_name = a
        if o == "-d":
            stdout.write("specifying date is not yet supported\n")
            exit(1)
    if not template_path or not interface_name:
        usage(argv)
        exit(1)
    license_early_check(template_path)
    mac = bytes(get_mac(interface_name))
    license_code = generate_license_code(mac)
    output_licese_file(license_code, template_path)