25. Internet Protocol (IP) Pipeline Sample Application

The Internet Protocol (IP) Pipeline application illustrates the use of the DPDK Packet Framework tool suite. The DPDK pipeline methodology is used to implement functional blocks such as packet RX, packet TX, flow classification, firewall, routing, IP fragmentation, IP reassembly, etc which are then assigned to different CPU cores and connected together to create complex multi-core applications.

25.1. Overview

The pipelines for packet RX, packet TX, flow classification, firewall, routing, IP fragmentation, IP reassembly, management, etc are instantiated and different CPU cores and connected together through software queues. One of the CPU cores can be designated as the management core to run a Command Line Interface (CLI) to add entries to each table (e.g. flow table, firewall rule database, routing table, Address Resolution Protocol (ARP) table, and so on), bring NIC ports up or down, and so on.

25.2. Compiling the Application

  1. Go to the examples directory:

    export RTE_SDK=/path/to/rte_sdk
    cd ${RTE_SDK}/examples/ip_pipeline
  2. Set the target (a default target is used if not specified):

    export RTE_TARGET=x86_64-native-linuxapp-gcc
  3. Build the application:


25.3. Running the Sample Code

The application execution command line is:

./ip_pipeline [EAL options] -- -p PORTMASK [-f CONFIG_FILE]

The number of ports in the PORTMASK can be either 2 or 4.

The config file assigns functionality to the CPU core by deciding the pipeline type to run on each CPU core (e.g. master, RX, flow classification, firewall, routing, IP fragmentation, IP reassembly, TX) and also allows creating complex topologies made up of CPU cores by interconnecting the CPU cores through SW queues.

Once the application is initialized, the CLI is available for populating the application tables, bringing NIC ports up or down, and so on.

The flow classification pipeline implements the flow table by using a large (multi-million entry) hash table with a 16-byte key size. The lookup key is the IPv4 5-tuple, which is extracted from the input packet by the packet RX pipeline and saved in the packet meta-data, has the following format:

[source IP address, destination IP address, L4 protocol, L4 protocol source port, L4 protocol destination port]

The firewall pipeline implements the rule database using an ACL table.

The routing pipeline implements an IP routing table by using an LPM IPv4 table and an ARP table by using a hash table with an 8-byte key size. The IP routing table lookup provides the output interface ID and the next hop IP address, which are stored in the packet meta-data, then used as the lookup key into the ARP table. The ARP table lookup provides the destination MAC address to be used for the output packet. The action for the default entry of both the IP routing table and the ARP table is packet drop.

The following CLI operations are available:

  • Enable/disable NIC ports (RX pipeline)
  • Add/delete/list flows (flow classification pipeline)
  • Add/delete/list firewall rules (firewall pipeline)
  • Add/delete/list routes (routing pipeline)
  • Add/delete/list ARP entries (routing pipeline)

In addition, there are two special commands:

  • flow add all: Populate the flow classification table with 16 million flows (by iterating through the last three bytes of the destination IP address). These flows are not displayed when using the flow print command. When this command is used, the following traffic profile must be used to have flow table lookup hits for all input packets. TCP/IPv4 packets with:
    • destination IP address = A.B.C.D with A fixed to 0 and B,C,D random
    • source IP address fixed to 0
    • source TCP port fixed to 0
    • destination TCP port fixed to 0
  • run cmd_file_path: Read CLI commands from an external file and run them one by one.

The full list of the available CLI commands can be displayed by pressing the TAB key while the application is running.