Research And Implementation Of IPv6 Dataflow Reassembly

With the development of Internet, Information technology began to play a important role in our national economy, people became more and more dependent on computers which bring to convenience our daily life. But the control of distributing IPv4 addresses is not quite reasonable at the beginning of the IPv4 is designed, leds the allocation of address resource with great imbalance. There is a great discrepancy between addresses China owns and China demands, which seriously constraints the development of the applicant and development of Internet in china. IPv6 (Internet Protocol Version 6), as the next generation Internet protocol , is an alternative version of IPv4, which bring opportunities and challenges for the future development of Internet. Now IPv6 has received supports of several main network operators and organizations, and has been deployed over the country. The research and application of IPv6 protocol begin to get more and more attention.IPv6 is an upgrade and improved version of IPv4, but segmentation and reorganization of data packet is still exits as an important module of the underlying protocol in IPv6. Good segmentation and reorganization algorithm plays an important role in network fragmentation attacks and enhancing system's packet processing capacity, and also provides probability to high-speed analysis and reduction of the upper layer protocol.This paper first analysised the mechanism of packet capture in Linux, gave a brief introduction of packet capture library Libpcap. The system achieved two packet capture mode by using the interface provided by Libpcap libraries and PF_RING module, which can be choosen as the user needed; Also the system achieved a multi-threaded IPv6 segmentation and reorganization module by improving the IPv4 reorganization algorithm proposed in RFC791 and RFC815, which gave a full play to the advantage of the multi-core computers and make more rational use of hardware resources; Finally, the system the segmented data stream goes through TCP reorganization module and protocol reduction module, achieved ICMPv6, HTTP and FTP protocol reduction, and so on.Finally, this paper did performance or functional testing on underlying data capture module, segmentation and reorganization module, TCP data flow reorganization module and protocol reduction module, which all achieved the desired results. At last, summarizes the current work and proposed future directions for improvement.