Research And Implementation Of In-vehicle Gateway Switching Protocols Between IPv6 And CAN Based On Virtual Devices

With the birth of IPv6 and the rapid development of things, more and more material will have its own independent IPv6 address, and are connected through the network, forming a physical object connected with the Internet.As things a typical application example, automotive electrical systems will become the property connected nodes in the network node unit.And because the popularity of Ethernet, via the Internet to obtain information on the requirements of each node is also increasingly urgent.To address this need, automotive design and development of the gateway is particularly important.CAN nodes on the adoption of this model in the virtual gateway vehicle design, shielding and unified way to access the CAN nodes, design and implementation of high throughput and high maintainability of the vehicle gateway.As China's automotive electronics industry level in the lower level also belongs, has yet to realize the car with the remote host connected to the network service. The implementation of the Gateway board will fill the gaps in this area. In the existing CAN bus and Ethernet gateway, some gateway in the design of the hardware interface need to change, which increases the difficulty of the design and implementation costs; and some can not achieve the realization of the gateway Two-way channel of operation. In Linux operating system to work as an example, because the original the CAN bus driver is through a serial port equipment access to interact with the operating system CAN bus, so when the data on the frame to the operating system kernel, operating system just after the data frame is copied to the user space and then wait for the user space after a process scheduling into IP data submitted to encapsulate send. So not only increase the burden of the operating system, also can make the data transmission occur in large data reported delays, first will produce unpredictable errors.To solve the net-connection problem between remote entity and vehicle system, this paper designs and implements a kind of gateway which can switch protocols between IPv6 and CAN. Simulating the CAN entities' equipments in the vehicle's gateway and distributes an IPv6 address to each virtualized CAN entity, so that the remote entity could operate the entity. Since the application of IPv6, the methods of remote entity accesses CAN entity are consolidated. According to the change of the access method of CAN bus, the CAN equipment driver with traditional access method by reading and writing files is replaced by the net equipment driver, which promotes the gateway's capability extremely. Finally, performances of the proposed method are demonstrated by the application.CAN node through the virtual design, so that each CAN node has its own independent IPv6 addresses, which are managed and maintained by the gateway. Linux virtual device not only can effectively simulate the work of some real equipment, but will also screen a number of low-level details of the application layer provides a uniform access interface.In this model in the design and implementation of, the gateway for each CAN node IPv6 addresses all maintenance a visit to outside, so it CAN bus, each node IPv6 address by the visit. On-board gateway and remote hosts are interconnected via CDMA network between, in the on-board gateway is CDMA receivers receiving data report was first put Linux kernel protocol stack Packet module and was intercepted by Packet module runs on Linux, network architecture network layer and the data link layer between, it realized the function of route data submitted from, when discovering the IP data report is sent to virtual CAN node, will this data submitted CAN_MODULE module to.CAN_MODULE module is the core part of the vehicle, which shall include the initialization of the CAN bus, software reset, up CAN controller interrupts and other functions, but also by simulating Ethernet card device drivers, have their own independent receive and Send data reported function, and can the data reported for special handling. CAN node through the virtual management, will the actual CAN bus CAN nodes and virtual nodes correspond.Effective simulation of virtual CAN node devices work some real effect, and the real part of the information stored in the device gateway, shielding the real devices to access different differences. As part of the real property to the preservation of equipment, but also makes the CAN frames in Gateway package targeted to achieve the CAN node to the remote host access.