icmp-ping.py 文件源码

def ping_once(ip_addr, timeout):
    """
    return either delay (in second) or none on timeout.
    """
    # Translate an Internet protocol name to a constant suitable for
    # passing as the (optional) third argument to the socket() function.
    # This is usually only needed for sockets opened in “raw” mode.
    icmp = socket.getprotobyname('icmp')
    try:
        # socket.socket([family[, type[, proto]]])
        # Create a new socket using the given address family(default: AF_INET),
        # socket type(SOCK_STREAM) and protocol number(zero or may be omitted).
        my_socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, icmp)
    except socket.error:
        raise

    # Return the current process id.
    # int: 0xFFFF = -1, unsigned int: 65535
    my_ID = os.getpid() & 0xFFFF

    send_ping(my_socket, ip_addr, my_ID)
    delay = receive_ping(my_socket, my_ID, timeout)

    my_socket.close()
    return delay