RouterKitWalkthrough

Table of Contents Router Kit Walkthrough Overview Running Router Kit Using Router Kit How it Works What to do From Here

Router Kit Walkthrough

Overview

Router Kit is a simple approach to providing hardware acceleration to an unmodified Linux system. It is comprised of a single program, rkd (Router Kit Daemon), which monitors the Linux routing table and ARP cache and mirrors it down to the NetFPGA IPv4 reference router implementation.

Running Router Kit

   rkd [-h||--help} [-d||--daemon} [-i||--interval]  

rkd should work from the command line without any external configuration options. Simply run (./rkd). To run the process in the background use -d. You may specify the polling time in milliseconds using the -i option.

Using Router Kit

Router Kit is only useful on a Linux host with NetFPGA2 installed, and the ipv4 reference router bitfile loaded. Given this setup each port on the NetFPGA2 card is available to Linux via a nfc* interface (i.e. nfc0, nfc1, nfc2, and nfc3 assuming a single card is installed).

rkd will attempt to mirror all ARP cache and routing table entries associate with a NetFPGA interface into hardware. This provides a very simple (and familiar) method of of adding entries to the hardware. For example, to add a static ARP entry, simply use the arp(8) command. The following command will add a static ARP entry.

    arp -s 1.2.3.4 ca:fe:de:ad:d0:d0 -i nfc0 

To add an entry into the routing table, use route(8) (or ip(8)). For example, adding a default entry with a next hop of 10.0.0.1 out of the first port would look something like:

    route add default gw 10.0.0.1 dev nfc0 

Router kit is not limited to manual manipulation from the command line. All state (including dynamic state) is mirrored. To wit, running rkd alongside a standard routing daemon, such as XoRP, or Zebra/Quagga, should provide hardware acceleration of the forwarding table without any further configuration (provided the routing software is using the NetFPGA interfaces for forwarding).

How it Works

rkd continuously polls the routing table and ARP cache state from /proc/net/route and /proc/net/arp respectively. When a change in state is detected, ./rkd writes the updated state to the NetFPGA through the register interface. All traffic not handled by the hardware is DMA'd to software where it is processed by the Linux kernel.

What to do From Here

• You can go through the Reference NIC Walkthrough if you are interested in using the NetFPGA as a network interface card
• You can go through the SCONE Software Walkthrough if you are interested in writing software for the NetFPGA to run in the host
• You can go through the Reference Router Walkthrough if you are interested in modifying the gateware on the FPGA
• You can go through the Buffer Monitoring System Walkthrough if you are interested in how to test/measure the lengths of buffers.
• Return to the Main Guide