uncloud/ucloud/common/network.py

import subprocess as sp
import random
import logging
import socket
from contextlib import closing

logger = logging.getLogger(__name__)


def random_bytes(num=6):
    return [random.randrange(256) for _ in range(num)]


def generate_mac(
    uaa=False, multicast=False, oui=None, separator=":", byte_fmt="%02x"
):
    mac = random_bytes()
    if oui:
        if type(oui) == str:
            oui = [int(chunk) for chunk in oui.split(separator)]
        mac = oui + random_bytes(num=6 - len(oui))
    else:
        if multicast:
            mac[0] |= 1  # set bit 0
        else:
            mac[0] &= ~1  # clear bit 0
        if uaa:
            mac[0] &= ~(1 << 1)  # clear bit 1
        else:
            mac[0] |= 1 << 1  # set bit 1
    return separator.join(byte_fmt % b for b in mac)


def create_dev(script, _id, dev, ip=None):
    command = [
        "sudo",
        "-p",
        "Enter password to create network devices for vm: ",
        script,
        str(_id),
        dev,
    ]
    if ip:
        command.append(ip)
    try:
        output = sp.check_output(command, stderr=sp.PIPE)
    except Exception:
        logger.exception("Creation of interface %s failed.", dev)
        return None
    else:
        return output.decode("utf-8").strip()


def delete_network_interface(iface):
    try:
        sp.check_output(
            [
                "sudo",
                "-p",
                "Enter password to remove {} network device: ".format(
                    iface
                ),
                "ip",
                "link",
                "del",
                iface,
            ],
            stderr=sp.PIPE,
        )
    except Exception:
        logger.exception("Interface %s Deletion failed", iface)


def find_free_port():
    with closing(
        socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    ) as s:
        try:
            s.bind(("", 0))
            s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        except Exception:
            return None
        else:
            return s.getsockname()[1]