detect.py 文件源码

def get_interface_ip(sock: socket.socket, ifname: str) -> str:
    """Obtain an IP address for a network interface, as a string."""
    ifreq_tuple = (ifname.encode('utf-8')[:15], socket.AF_INET, b'\x00' * 14)
    ifreq = struct.pack(b'16sH14s', *ifreq_tuple)
    try:
        info = fcntl.ioctl(sock, SIOCGIFADDR, ifreq)
    except OSError as e:
        if e.errno == errno.ENODEV:
            raise InterfaceNotFound(
                "Interface not found: '%s'." % ifname)
        elif e.errno == errno.EADDRNOTAVAIL:
            raise IPAddressNotAvailable(
                "No IP address found on interface '%s'." % ifname)
        else:
            raise IPAddressNotAvailable(
                "Failed to get IP address for '%s': %s." % (
                    ifname, strerror(e.errno)))
    else:
        # Parse the `struct ifreq` that comes back from the ioctl() call.
        #     16x --> char ifr_name[IFNAMSIZ];
        # ... next is a union of structures; we're interested in the
        # `sockaddr_in` that is returned from this particular ioctl().
        #     2x  --> short sin_family;
        #     2x  --> unsigned short sin_port;
        #     4s  --> struct in_addr sin_addr;
        #     8x  --> char sin_zero[8];
        addr, = struct.unpack(b'16x2x2x4s8x', info)
        ip = socket.inet_ntoa(addr)
    return ip