Network Shaper

This project is a very simplistic user interface for netem. It is designed to allow users to apply basic traffic shaping rules to simulate poor network conditions without being required to learn the netem command line interface.

The UI is written using polymer, mostly as an excuse for me to become familiar with polymer. The backend is written in Go, and should have no external dependencies when built (aside from tc, of course).

I'm sure there are plenty of things that can be done to improve both the UI and backend of this project. Contributions are more than welcome, particularly in the area of cleaning out cruft from this repository (which was created using the contents of the polymer starter kit.

Assumptions

This tool was built for a particular scenario, and some assumptions are made because of it.

• It is assumed that the service will run as root in order to apply changes to the network interfaces. No special logic currently exists to ensure that the executable can do what it needs to before starting to handle requests from the UI.

• It is assumed that the server will reside on a machine with two physical network interfaces, one for "external" traffic coming into the network controlled by this tool, and another interface for "internal" traffic leaving the controlled network.

  This tool has only been tested on a machine with two physical Gigabit network interfaces.

Screenshots

Building

The requirements for building this project are:

• nodejs for npm, to install other dependencies
• gulp as a build tool
• bower, a package manager
• Go 1.x (currently built with 1.4.2)
• go-bindata to bundle static assets into the Go binary
• go-bindata-assetfs to easily serve the web UI
• upx to compress binaries
• goupx to fix a bug in upx to handle 64-bit Go binaries

The steps to build this tool are:

$ npm install gulp                                  # install gulp
$ npm install bower                                 # install bower
$ npm install                                       # install polymer starter kit dependencies
$ bower install                                     # install UI dependencies
$ go get github.com/jteeuwen/go-bindata/...         # for bundling the UI
$ go get github.com/elazarl/go-bindata-assetfs/...  # for serving the UI
$ make dist                                         # compile UI and executable

At this point, the network-shaper binary should appear in the server/ directory. This is the final executable.

You can proceed to build an RPM using the following command:

$ make rpm

Or you may build an ArchLinux package:

$ make arch

Using This Tool

Once you have the network-shaper binary, you may invoke it using the command line as such:

# network-shaper -c config.json

A sample configuration file can be found in the repository as sample.json and looks like this:

{
  "host": "0.0.0.0",
  "port": 80,
  "inbound": {
    "device": "enp2s0",
    "netem": {
      "delay": 0,
      "delay_unit": "ms",
      "delay_jitter": 0,
      "delay_jitter_unit": "ms",
      "delay_corr": 0,
      "loss_pct": 0,
      "loss_corr": 0,
      "dupe_pct": 0,
      "dupe_corr": 0,
      "corrupt_pct": 0,
      "corrupt_corr": 0,
      "reorder_pct": 0,
      "reorder_corr": 0,
      "reorder_gap": 0,
      "rate": 0,
      "rate_unit": "kbit",
      "rate_pkt_overhead": 0,
      "rate_cell_size": 0,
      "rate_cell_overhead": 0
    }
  },
  "outbound": {
    "device": "enp4s0",
    "netem": {
      "delay": 0,
      "delay_unit": "ms",
      "delay_jitter": 0,
      "delay_jitter_unit": "ms",
      "delay_corr": 0,
      "loss_pct": 0,
      "loss_corr": 0,
      "dupe_pct": 0,
      "dupe_corr": 0,
      "corrupt_pct": 0,
      "corrupt_corr": 0,
      "reorder_pct": 0,
      "reorder_corr": 0,
      "reorder_gap": 0,
      "rate": 0,
      "rate_unit": "kbit",
      "rate_pkt_overhead": 0,
      "rate_cell_size": 0,
      "rate_cell_overhead": 0
    }
  }
}

The most basic configuration file would look like this:

{
  "host": "0.0.0.0",
  "port": 80,
  "inbound": {
    "device": "enp2s0"
  },
  "outbound": {
    "device": "enp4s0"
  }
}

The rest of the configuration file is generated by the tool once you apply settings.

The purpose of these configuration values are:

• host: the IP to bind the web UI to. 0.0.0.0 means that the server will accept requests on any interface on the host machine. 127.0.0.1 means the server will only accept requests made from the host itself.
• port: the TCP port on which the server will accept requests. Note that if you have any other web server software installed and running, such as Apache or Nginx, port 80 will likely conflict with their default configuration.
• inbound.device: the name of the network interface connected to the "internal" network, or the network that is influenced by the rules set by this tool.
• outbound.device: the name of the network interface connected to the "external" network, or the network that is not influenced by the rules set by this tool.

Contributing

We welcome your bug reports, PRs for improvements, docs and anything you think would improve the experience for other developers.