Crate str0m_netem 

Sans-IO network emulator inspired by Linux netem.

This crate provides a network emulator that can simulate:

• Latency and jitter
• Packet loss (random or bursty via Gilbert-Elliot model)
• Packet duplication
• Packet reordering
• Rate limiting

Sans-IO Pattern

This implementation follows the Sans-IO pattern: packets go in with timestamps, and decisions come out (drop, delay, duplicate). The caller handles actual I/O and timing.

Example

use std::time::{Duration, Instant};
use str0m_netem::{Netem, NetemConfig, Input, Output, LossModel, RandomLoss, Probability};

let config = NetemConfig::new()
    .latency(Duration::from_millis(50))
    .jitter(Duration::from_millis(10))
    .loss(RandomLoss::new(Probability::new(0.01)))
    .seed(42);

let mut netem: Netem<Vec<u8>> = Netem::new(config);

// Send a packet
let now = Instant::now();
netem.handle_input(Input::Packet(now, vec![1, 2, 3]));

// Poll for output
while let Some(output) = netem.poll_output() {
    match output {
        Output::Timeout(when) => {
            // Wait until `when` and call handle_input with Input::Timeout
        }
        Output::Packet(data) => {
            // Send the packet
        }
    }
}

Structs

Bitrate

A data rate expressed as bits per second(bps).

DataSize

A data size expressed in bytes.

GilbertElliot

Gilbert-Elliot loss model with two states: GOOD and BAD.

Link

A bottleneck link with rate limiting and finite buffer.

Netem

Sans-IO network emulator.

NetemConfig

Configuration for the network emulator.

Probability

Probability in range 0.0..=1.0

RandomLoss

Random loss model configuration.

Enums

Input

Input events to the network emulator.

LossModel

Loss model for packet dropping.

Output

Output events from the network emulator.

Traits

WithLen

Trait for getting the length of packet data (used for rate limiting).