zerotier_info.py

#!/usr/bin/env python3.8
from ipaddress import IPv6Network, IPv6Address
from typing import Optional, Tuple
from base64 import b32encode

# from https://github.com/zerotier/ZeroTierOne/blob/91b16310ea47a6de96edb488a61494f8ed8c139c/node/InetAddress.cpp#L427
def mk6plane(nwid: int, nodeid: int
) -> Tuple[IPv6Network, IPv6Network, IPv6Address]:
    """
    Given a ZeroTier node and network ID, return
    a tuple where the first element is the subnet for the
    whole 6plane network, the second is the subnet 
    assigned to the given node id and the 6plane address
    for that node
    """
    prefix = (nwid ^ (nwid >> 8*4)) & ((1 << 8*4) - 1)
    net = IPv6Network(((0xfc << 8*15) +
                       (prefix << 8*11) +
                       (nodeid << 8*6), 80))
    return net.supernet(new_prefix=40), net, net[1]

# from https://github.com/zerotier/ZeroTierOne/blob/b6b11dbf8242ff17c58f10f817d754da3f8c00eb/osdep/LinuxEthernetTap.cpp#L143-L159
def ifname(nwid: int, trial: int = 0) -> str:
    """
    Given a ZeroTier network ID and a trial number, compute
    the linux interface name for the network adapter
    """
    nwid40 = (nwid ^ (nwid >> 8*3) + trial) & ((1 << 8*5) - 1)
    return "zt" + b32encode(nwid40.to_bytes(5, "big")
        ).decode().lower()