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pragmaticflows

pragmaticflows is being used at AmLight to assess the conformance of OpenFlow version 1.3 on certain switch platforms focused on use cases for production networks pragmatically. pragmaticflows is a Ryu application which was forked from the classic Ryu test suites.

Enhancements

  • Fully integrated with pytest for first-class test cases selection and HTML reports. You can select or troubleshoot/debug each test case individually thanks to pytest.
  • All test cases written in json files have been refactored with actual variables so you can use with any OF1.3 switches regardless of their port numbers.
  • Flowmods, PacketIns, PacketOuts and Errors are all logged to simplify the analysis, so just by analyzing the report you'll be able to figure out what happened.
  • Removed miss tables checks, packet-ins are checked in instead, to reduce false positives.
  • Removed all MPLS and PBB packets that were in several use cases since most vendors don't actually support these features.

Report

Here's a screenshot of the report that you should expect when you run pragmaticflows with the --html-report.html --self-contained-html options:

SS

Topology

  • You'll need at least two links between the two OpenFlow switches. A third link is only necessary for advanced other more elaborated features such as multicast groups and QoS metering, which is not implemented yet on pragmaticflows yet.
  • There are two switches involved, the one being under test the target switch and the auxiliary.
  • Also, you'll need a controller running RYU to control these switches, as long as you have IP reachability that's all that matters.
------------------
    (1) -- (1)
 s1 (2) -- (2) s2
------------------
  • s1 and s2 represent an OpenFlow 1.3 switch.
  • The numbers (1) and (2) in the topology are the of_port numbers.

The topology is specified in a yml format, which is passed as an environment variable, see the Test Selection section bellow. Take a look on topology.yml for example.

Pre-requisites

Before running any test cases:

  1. Make sure there aren't any type of unexpected network packets being sent on the interfaces being tested. This Ryu application relies on OpenFlow stats/counters/PacketIns/PacketOuts, so this is critical. For example, disable spanning tree, LLDP and other L2 multicast protocols. Ideally, you should run a sniffer on these interfaces for a few minutes before starting to verify this point.
  2. Install Ryu, either pip install requirements.txt on a virtualenv or docker-compose up if you want run Ryu on Docker.
  3. Figure out which test cases you want to run.
  4. Figure out all the OpenFlow interface numbers on the tester (auxiliary switch) and target (device under test), and their datapath ids you'll need to pass them to ryu-manager.
  5. Read Ryu Official Test Tool page to understand how validation packets will be sent over these three links in the topology.
  6. Configure the OpenFlow switches to point out to the RYU controller.

Test Suites

These are the test suites, each folder has the .json files that specify the test cases. So, to add a new test case you have to either edit an existing json file, or if it makes sense create a new one. Currently, they're being grouped into folders, but folders doesn't not reduce the flexibility of the test selection thanks to pytest.

~/repos/pragmaticflows/tests master*
❯ tree -L 1
.
├── eth
├── in_port
├── ipv4
├── ipv6
├── lldp
├── qinq
├── test_all.py
└── vlan

Test Selection

There's a pytest_args, where you can pass any pytest argument, so you can select tests or just collect them based on this variable.

Collecting test cases

You can use the --collect-only argument, you can see bellow the Functions and the id of each test case. So typically you just collect first, narrow down a test case and run it.

❯ topo=topology_cnet.yml pytest_args="-v -s --collect-only --html=report.html --self-contained-html" ryu-manager --log-config-file logging.ini oftester/oftester.py
-----> 2018-06-15 10:22:57,055 INFO [ryu.base.app_manager]
loading app oftester/oftester.py
<Module 'tests/test_all.py'>
  <Function "test[match_ipv6_flowlabel.json_id_0_ethernet/ipv6(flow_label=100)/tcp-->'ipv6_flabel=100,actions=output:target_send_port_1']">
  <Function "test[match_ipv6_flowlabel.json_id_1_ethernet/ipv6(flow_label=100)/tcp-->'ipv6_flabel=100,actions=output:CONTROLLER']">
  <Function "test[match_ipv6_flowlabel.json_id_2_ethernet/ipv6(flow_label=203)/tcp-->'ipv6_flabel=100,actions=output:target_send_port_1']">
  <Function "test[match_ipv6_flowlabel.json_id_3_ethernet/vlan/ipv6(flow_label=100)/tcp-->'ipv6_flabel=100,actions=output:target_send_port_1']">
  <Function "test[match_ipv6_flowlabel.json_id_4_ethernet/vlan/ipv6(flow_label=100)/tcp-->'ipv6_flabel=100,actions=output:CONTROLLER']">

For example, if you want to target anything that is related to LLDP, you can use the -k parameter to pass a regex, as you can see there are just two test cases that test the matching capabilitities with LLDP:


❯ topo=topology_cnet.yml pytest_args="-v -s --collect-only -k lldp --html=report.html --self-contained-html" ryu-manager --log-config-file logging.ini oftester/oftester.py
<Module 'tests/test_all.py'>
  <Function "test[match_lldp.json_id_144_ethernet/lldp-->'eth_type=target_recv_port,actions=output:target_send_port_1']">
  <Function "test[match_lldp.json_id_145_ethernet/vlan/lldp-->'vlan_100/lldp=target_recv_port,actions=output:target_send_port_1']">

Running just a subset of test cases

If we were to run just the LLDP test cases mentioned before, you just have to pass the regex without the --collect-only argument.

❯ topo=topology_cnet.yml pytest_args="-v -s -k lldp --html=report.html --self-contained-html" ryu-manager --log-config-file logging.ini oftester/oftester.py
-----> 2018-06-15 10:28:50,308 INFO [ryu.base.app_manager]
loading app oftester/oftester.py
10:28:50 [ryu.base.app_manager] [INFO] loading app ryu.controller.ofp_handler
10:28:50 [ryu.base.app_manager] [INFO] instantiating app oftester/oftester.py of OfTester
10:28:50 [OfTester] [INFO] Topology:{ 'switch_target': { 'dpid': '0000000000000003',
                     'of_version': 'openflow13',
                     'recv_port': 2,
                     'send_port_1': 3,
                     'send_port_2': 4},
  'switch_tester': { 'dpid': '0000000000000004',
                     'of_version': 'openflow13',
                     'recv_port_1': 3,
                     'recv_port_2': 4,
                     'send_port': 2}}
10:28:50 [ryu.base.app_manager] [INFO] instantiating app ryu.controller.ofp_handler of OFPHandler
Test session starts (platform: linux, Python 3.6.5, pytest 3.6.1, pytest-sugar 0.9.1)
rootdir: /home/arcanjo/repos/pragmaticflows, inifile:
plugins: sugar-0.9.1, metadata-1.7.0, html-1.19.0
10:28:50 [OfTester] [INFO] Waiting for switches connection...
10:28:51 [OfTester] [INFO] dpid=0000000000000004 : Join tester SW.
10:28:51 [OfTester] [INFO] dpid=0000000000000003 : Join target SW.

Running all test cases, with HTML report:

Currently there are 190+ test cases, it takes almost 10 minutes to run:

topo=topology_cnet.yml pytest_args="-v -s --html=report.html --self-contained-html" ryu-manager --log-config-file logging.ini oftester/oftester.py