phantomlink looks like a multi-hop Internet path but emulates a virtual end-to-end link

phantomlink is a tool for studying the impact of a dynamic network environment on the performance of internet protocols and applications. Written in safe Rust, the tool makes use of Linux network namespaces and virtual Ethernet devices to simulate a realistic end-to-end link. Using simple .csv scenario files, it is possible to define the time-evolving virtual link parameters, including delay, data rate over time, and route changes. Since the tool just opens two connected vEth in different namespaces, it is possible to combine phantomlink with any application, such as the well-known tools like netcat or iperf but also your own custom application. With the ability to reorder, delay, pace, and drop packets, phantomlink can be used to test network behavior under various scenarios.

🔥 Features

• connect two Linux network namespaces over a dynamic virtual link
• specify bottleneck data rate, link delay, and packet reordering
• set the virtual link behavior with a simple input file format
• support for all protocols using ethernet frames ➡️ just route the traffic to phantomlink

🚀 Use phantomlink

Warning

Phantomlink currently only runs on Linux or the Windows Subsystem for Linux (WSL)

Installation

Debian/Ubuntu

1. Download the phantomlink debian package.
2. Install the package using (replace [version] with the downloaded version):

sudo apt install ~/downloads/phantomlink_[version].deb 

Cargo

To get started you have to do the following:

1. Install phantomlink from crates.io:

cargo install phantomlink

Other Distros

To get started you have to do the following:

1. Download the phantomlink binary.
2. Make the binary executable using:

chmod +x phantomlink_[version]

3. Move the binary to /bin.

Build from source

It is also possible to build the phantomlink binary from source.

Prerequisites

• Git installed on your system.
• Rust and Cargo installed (for building the binary).

Option 1: Manual Build

1. Clone the phantomlink repository from GitHub:

git clone https://github.com/robinohs/phantomlink

2. Navigate to the cloned repository and build the binary using Cargo:

cargo build --release

3. Move the binary to a directory that is in your system's PATH:

sudo mv target/release/phantomlink /bin/

Option 2: Use the Install Script

1. Clone the phantomlink repository from GitHub:

git clone https://github.com/robinohs/phantomlink

2. Navigate to the repository and execute the provided install.sh script:

cd phantomlink
./install.sh

Notes

Verify phantomlink is correctly installed by running:

phantomlink --version

Shell completions

phantomlink provides shell completion support for multiple shells, including bash, elvish, fish, PowerShell, zsh, and nushell. It automatically detects your default shell from the environment, so you don’t need to specify it unless you want to. To generate completions for a specific shell, use the command below. phantomlink will output the auto-completion code to stdout, allowing you to pipe it into the auto-completion file appropriate for your shell.

phantomlink generate <shell>

Quick-start

1. Download the input.csv file from examples.
2. Setup the network environment:

phantomlink setup

3. Start the main virtual link (assuming the input file is in ~/Downloads):

phantomlink start ~/Downloads/input.csv

4. Start an application in the server network namespace:

phantomlink exec server iperf3 -s --port 5000

5. Start an application in the client network namespace:

phantomlink exec client iperf3 -c 192.168.66.2 --port 5000

6. To get informations about the client or server network namespace you can use:

phantomlink exec <client/server> ifconfig

7. After the experiment has finished, you can teardown the network environment:

phantomlink teardown

🔍 Structure of phantomlink

Input Format

phantomlink runs on scenario files—simple .csv files that contain the (time-evolving) parameters of the virtual end-to-end link. This format is motivated by the actual physical variability that an end-to-end connection can be exposed to. Scenario files define the behavior of the virtual link over time, with parameters such as delay and data rate evolving throughout the experiment. The RouteID column indicates whether there is an actual route change or only updated parameters for the current route. phantomlink is agnostic of how the scenario file was created and whether the values are realistic. Users can create hand-crafted, synthetic scenarios or use output from any (orbital) dynamics simulator to perform systematic. Parameters are updated at specified times, creating a step function of changes. For example given the following table:

Time [ms]	RouteID	Delay [ms]	Btldr [Mbps]
0	0	41.0	80.0
11 000	0	41.2	80.2
23 000	1	37.0	100.0
40 000	1	36.7	101.5
60 000	1	37.0	100.1

• From t = 0 ms, a route with a one-way delay of 41.0 ms and a data rate of 80.0 Mbit/s is used.
• At t = 11 s, values are updated to 41.2 ms and 80.2 Mbit/s.
• At t = 23 s, the route changes, as indicated by a new RouteID.

Architecture

At its core, the phantomlink toolchain has a binary that operates in conjunction with Linux network namespaces and virtual Ethernet devices. The toolchain architecture consists of three network namespaces created with netns:

• Client Application Namespace
• PhantomLink Binary Namespace
• Server Application Namespace

The client and server namespaces are interconnected with the PhantomLink namespace using two virtual Ethernet devices, resulting in four virtual interfaces. For each virtual Ethernet device:

• One side is moved to the PhantomLink namespace (sim-veth)
• The other side is moved to the client or server namespace (veth)

After moving the interfaces, MAC and IP addresses are assigned. For each namespace except for the PhantomLink namespace:

• A loopback device is added
• veth is configured as the default route to enable traffic flow towards phantomlink

To allow traffic to flow from the client to the server namespace and vice-versa, the phantomlink binary forwards packets between the two (sim-veth) interfaces. This enables applications in the client or server namespace to send and receive traffic over the emulated virtual end-to-end link that evolves according to the scenario file.

Core Binary

The phantomlink binary is implemented in safe Rust to benefit from Rust’s performance and memory safety. The internal binary structure is depicted in the picture above.

1. Namespace and Raw Sockets:

   • phantomlink is started in the PhantomLink namespace.
   • It binds a raw sockets to the interfaces sim-veth1 and sim-veth2 each.

2. libpnet crate:

   • Using the Rust crate libpnet, phantomlink creates a pnet::datalink::Channel for each interface.
   • This allows phantomlink to send and receive at the data link layer.

3. OnewayVirtualLink:

   • All incoming traffic from the client is processed by a OnewayVirtualLink and forwarded to the server.
   • Similarly, a second OnewayVirtualLink instance handles all traffic from the server to the client.

The functionality and role of each individual component is explained in the paper.

� FAQ

I need help

Don't hesitate to file an issue or contact one of the authors!

How can I help?

Please have a look at the issues or open one if you feel that something is needed.

Any contributions are very welcome!

🏛 License

Phantomlink is dual-licensed under Apache License, Version 2.0 or MIT License.

🙏 Acknowledgement

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 101008233 (MISSION).

🤼 Contributing

We look forward to any kind of contributions!

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual-licensed as above, without any additional terms or conditions.

Contributors

Robin Ohs 💻 📖 🤔 🚧 🔬

Gregory 💻 📖 🤔 🔬

Andreas Schmidt 💻 🎨 📖 🤔 🔬 🧑‍🏫

This project follows the all-contributors specification. Contributions of any kind are welcome 😎.