Toward a Common Host Interface for Network Processors

Since their invention, network interfaces have generally been treated as special by operating systems because of their complexity and unique control requirements. In this paper we present a generic host interface through which an intelligent network interface or network processor can be managed as a simple networking device. To accomplish this, we push the complex network connection management and protocol processing code down onto the network interface. This new network processing platform is treated as a simple device by the host operating system. This model of host operating system interconnection provides for various network processor architectures to be handled identically using a well-defined kernel interface. Selection of the exact location for the kernel interface to the network processor was based on our goals to maximize the utility of the network processing platform, require no changes to existing network applications, and provide interoperability with existing network protocols (e.g. TCP, UDP). This paper documents the criteria and methodology used in developing such a kernel interface and discusses our prototype implementation using Linux kernel modules and our own ASIC-based intelligent network interface card.