Nic with stateful connection tracking

Abstract

Network interface apparatus includes packet processing circuitry, comprising hardware logic coupled between a network interface and a host interface for connection to a host processor. The hardware logic accesses a list of active connections established between the local processes running on the host processor and corresponding processes on other computers on the network and maintains context information with respect to each of the active connections. Upon receiving a packet from the network having a header identifying the packet as having been transmitted to a local process in accordance with a predefined transport protocol, the hardware logic checks the list to find a connection to which the packet belongs and upon finding the connection, verifies that the packet conforms to the respective state indicated by the context information for the connection and, if so, updates the context information and passes the packet to the local process.