I presented at IPFS Camp 2022 on mitigating Denial-of-Service attacks in peer-to-peer networks. I discussed resource management strategies such as enforcing backpressure and provided examples of coding pitfalls to avoid in Rust and Go. You can find the recording and slides of my talk below.

Slides

DOS

  • Denial-of-service attack
  • Hard in peer-to-peer as identities are cheap
  • Relevant for any scarce resource, e.g. CPU, memory(, file descriptors)

Do’s

  • Bound EVERYTHING
  • Once a bound is exceeded:
    • Drop item (good)
    • Enforce backpressure (good)

Do’s

Backpressure

  • Slow consumer should slow down a fast producer
  • Can improve resource utilization
  • Can improve latency

Don’ts

// Decode the length prefix of a message.
let l = uvi::decode::usize(msg_len_prefix)?;
// Allocate a corresponding buffer.
let buffer = vec![0; l];
// Read message into buffer.
socket.read_exact(&mut buffer)?;

Don’ts

for {
  // Receive a request.
  request := <- incomingRequests
  // Handle the request.
  go handleRequest(request)
}

Don’ts

loop {
  // Receive a request.
  let request = incoming_requests.next().await?;

  // Handle the request.
  spawn(async move {
      handle(request)
  });
}

Don’ts

loop {
  // Receive a request.
  let request = incoming_requests.next().await?;
  // Send the request somewhere else.
  request_channel.unbounded_send(request);
}

Don’ts

// Buffer of requests
let to_be_handled_later = Vec::new();

// ...

let request = incoming_requests.next().await?;
to_be_handled_later.push(request);