How can I convert a CIDR prefix to a dotted-quad netmask in Python?
For example, if the prefix is 12 I need to return 255.240.0.0.
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问题:
回答1:
You can do it like this:
def cidr(prefix): return socket.inet_ntoa(struct.pack(">I", (0xffffffff << (32 - prefix)) & 0xffffffff)) 回答2:
Here is a solution on the lighter side (no module dependencies):
netmask = '.'.join([str((0xffffffff << (32 - len) >> i) & 0xff) for i in [24, 16, 8, 0]])