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Short Description
OpenFlow to YAML Translator and Microservice
Full Description

= OFTR: OpenFlow to YAML Translator
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:toc-placement: preamble

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== What is oftr?

The oftr program translates binary[OpenFlow] messages to[YAML 1.2] and back again. It provides a uniform object syntax for working with the OpenFlow protocol programmatically.

  • Supports Linux and OS X
  • Supports OpenFlow versions 1.0, 1.1, 1.2, 1.3, 1.4
  • Optional JSON RPC Microservice supports:
    multiple incoming or outgoing connections auxiliary connections
    ** TLS and DTLS

Decode the OpenFlow messages in a ".pcap" file while retaining metadata such as timestamps:


$ oftr decode "filename.pcap"

oftr includes a JSON-RPC microservice that can operate as an OpenFlow
controller, agent, or both simultaneously. The JSON-RPC microservice can control
the OpenFlow protocol over an IPC channel using asynchronous JSON events.


$ oftr jsonrpc

=== YAML to OpenFlow

The following YAML input will produce an OpenFlow 1.3 message:


version: 4 # OpenFlow 1.3
buffer_id: NO_BUFFER
in_port: CONTROLLER # Use strings for special values and flags

- action: OUTPUT
  port: 0x11    # YAML supports hexadecimal numbers
  max_len: MAX

data: 'ffffffffffff0000000000010800'

The YAML syntax is based on OpenFlow 1.4, but the same input
can generate earlier protocol version messages. oftr is intelligent about
translating between OpenFlows versions. For example,
here's a FlowMod message specified using OpenFlow 1.4 syntax, but which will
output a "1.0" message because version 1 is explicitly specified.


type: FLOW_MOD
version: 1 # OpenFlow 1.0
cookie: 0
cookie_mask: 0xFFFFFFFFFFFFFFFF # Ignored; not present in OpenFlow 1.0
table_id: 0 # Ignored; not present in OpenFlow 1.0
command: ADD
idle_timeout: 10
hard_timeout: 30
priority: 2
buffer_id: NO_BUFFER
out_port: ANY
out_group: ANY
flags: [ SEND_FLOW_REM, CHECK_OVERLAP ] # Flags as array of strings

  - field: IN_PORT
    value: 1
  - field: IPV4_SRC     # Match field dependencies added automatically
    value: ''
  - instruction: APPLY_ACTIONS
      - action: OUTPUT
        port: 2
        max_len: MAX

=== OpenFlow to YAML

Given a binary OpenFlow message, oftr can translate it back to a human-readable
YAML object. Here's the binary for an OpenFlow OFPT_ERROR message in hexadecimal:


01010013 00000062 00010001 FFFF1234 567890

Decoding this binary OpenFlow message yields:


type: ERROR
xid: 0x00000062
version: 0x01

data: FFFF1234567890

== Installation

Before you build, you need a C++11 compiler, cmake and git. You will also need
Python, Perl and Go.

On Ubuntu, use apt-get to install the dependencies.


$ sudo apt-get -yq update

$ sudo apt-get install build-essential cmake git golang libpcap-dev

On Mac OS X, you can obtain cmake from

To build the software:


$ git clone --recursive
$ mkdir oftr/Build
$ cd oftr/Build
$ cmake ..
$ make
$ make test

$ make install

On Ubuntu, you can also install the software from a[Launchpad PPA].

== Examples

To translate a text file into binary OpenFlow messages:


$ oftr encode -o output.bin input.yml

To translate a text file into binary OpenFlow messages, while ignoring
sets of match fields with missing prerequisites:


$ oftr encode --unchecked-match -o output.bin input.yml

To translate a text file of compact, single line JSON objects separated by


$ oftr encode --json input.json

To decode a file of binary OpenFlow messages to YAML:


$ oftr decode input.bin

To decode a ".pcap" file containing OpenFlow messages, treating all TCP streams
as potential OpenFlow connections:


$ oftr decode --pcap-filter='' "input.pcap"

To decode a file of binary OpenFlow messages to compact single-line JSON objects:


$ oftr decode --json "filename"

To decode binary OpenFlow messages to a valid JSON array of objects:


$ oftr decode --json-array "filename"

To decode binary OpenFlow messages with the additional check that the resulting
YAML produces the same binary message when re-encoded:


$ oftr decode --verify-output "filename"

The oftr help tool provides information about the schema used for reading/writing
OpenFlow messages in YAML. To obtain information about the syntax for the
'FLOW_MOD' message:


$ oftr help flow_mod

To list all supported OXM fields:


$ oftr help --fields

See the three man pages for details:[oftr],[oftr-jsonrpc],[oftr-schema].

== License

This software is licensed under the terms of the MIT License.

oftr relies on the following third-party source code (static linked):

For unit tests, oftr uses googletest:

For testing, oftr uses OpenFlow message samples from these projects:

Docker Pull Command
Source Repository

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