Firstly, The paper introduces the principle of sniffer technology to capture data packets, illustrates the structure and functions of libpcap library and winpcap(the windows version of libpcap) based on BPF and presents the design of packet capture class.

• 首先，本文介绍了用于数据包捕获的网络嗅探技术的工作原理，在给出BSD数据包过滤器(BPF)的基础上，对实现sniffer的libpcap库函数及winpcap(libpcap的windows版本)的框架和使用作了详细介绍，并给出应用winpcap实现数据包获取类的设计。