Research And Implementation Of Home Agent Tunneling Mechanism Of MIPv6 Based On Linux

MIPv6 node(MN) are identified by their home addresses regardless access points to Internet, after leaving home link temporary address called Care Of Address(COA) could be assigned to them indicating their positions to which packets delivering to home addressed would be tunneled, therefore Home agent(HA) play a great part in MIP technology.By now MIPv6 is still on the way, but relevant researches have already been doing. Linux is open, free and abundant in software, idea of doing MIPv6 researches on it is logically reasonable. MIPL(Mobile IPv6 for Linux), which is supported by HUT, have released several versions and is a great work of MIPv6 in Linux. Differing from MIPL which is pack whole itself into kernel, this paper tried to transplant HA tunneling function into userspace on behalf of both mini-kernel-desire and stable-kernel-desire application. Furthermore, the needs for diverse applications decide diversity of implementation of MIPv6, in this way, the paper make sense.This paper breaks HA tunneling mechanism into two sequent steps:①builds and maintains a binding cache for MN belonging to same links;②intercepts and tunnels packets addressed to MN's home address to COA.Then five functional modes have been present to realize the two steps, they are:①Analyzed the possible maximum tunneling capacity of HA in 1000M Ethernet, the paper supports hash as lookup algorithm and gives data structure for binding cache.②Detailed every field of Neighbor Advertisement Message.③Intensively investigated iptables rules and its source codes, designed code pieces adding iptables rules based on libiptc.④Through libnetfilter_queue API queuing packets to userspace competing with ip_queue API.⑤Delivering packets through IPv6 in IPv6 tunnel with analyzing work.Link these five modes together and it really,alrough roughly works in Linux, besides binding updates has been ignored. However iptables rules couldn't be added by C but hands instead.