Much of the IP data is not useful, beyond the protocol and source/destination address information.

其中除了协议和来源/目标地址信息，其余许多 IP 数据是没有用的。

youdao

The number of bytes reserved for the remote address information. This value must be at least 16 bytes more than the maximum address length for the transport protocol in use. Cannot be zero.

“要比系统给的最大地址长度至少要多16个字节”，而我的代码没有多这16个字节，问题就出在这里，修改一下，再运行，就没问题了；

youdao

If the user enters the wrong password several times and then is connected to the Internet, the company will locate the computer through its Internet protocol address, information that can help law enforcement agencies recover the computer, Lide said.

CNN: Mobile PCs can be risky on the road