252. Sample Application Tests: Netmap Compatibility

252.1. Introduction

The Netmap compatibility library provides a minimal set of APIs to give programs written against the Netmap APIs the ability to be run, with minimal changes to their source code, using the DPDK to perform the actual packet I/O.

Since Netmap applications use regular system calls, like open(), ioctl() and mmap() to communicate with the Netmap kernel module performing the packet I/O, the compat_netmap library provides a set of similar APIs to use in place of those system calls, effectively turning a Netmap application into a DPDK application.

The provided library is currently minimal and doesn’t support all the features that Netmap supports, but is enough to run simple applications, such as the bridge example detailed below.

Knowledge of Netmap is required to understand the rest of this section. Please refer to the Netmap distribution for details about Netmap.

252.2. Running the “bridge” Sample Application

The application requires a single command line option:

./build/bridge [EAL options] -- -i INTERFACE_A [-i INTERFACE_B]

Where:

  • -i INTERFACE: Interface (DPDK port number) to use.

    If a single -i parameter is given, the interface will send back all the traffic it receives. If two -i parameters are given, the two interfaces form a bridge, where traffic received on one interface is replicated and sent to the other interface.

For example, to run the application in a linuxapp environment using port 0 and 2:

./build/bridge [EAL options] -- -i 0 -i 2

Refer to the DPDK Getting Started Guide for Linux for general information on running applications and the Environment Abstraction Layer (EAL) options.

252.3. Test Case1: netmap compat with one port

Run bridge with one port:

./examples/netmap_compat/build/bridge -c 0x1e -n 4 -- -i 0

waked up:

Port 0 now in Netmap mode
Bridge up and running!

Send one packet on Port0,check this port receive packet. It receive one packet that it send.

252.4. Test Case2: netmap compat with two port

Run bridge with two ports:

./examples/netmap_compat/build/bridge -c 0x1e -n 4 -- -i 0 -i 1

waked up:

Port 0 now in Netmap mode
Port 1 now in Netmap mode
Bridge up and running!

Send one packet on Port0,check the port1 receive packet. It receive one packet that the port0 send.