Isla

An Experimental Rust TCP/IP Stack

Warning

Project Isla is an experimental learning project, not a production-ready network stack. It is not suitable for general internet use.

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Project Isla is a custom, no_std-compatible TCP/IP implementation developed in Rust. It operates by bypassing the Linux kernel networking stack to communicate directly with a TAP interface using raw Ethernet frames.

The objective of this project is to explore the mechanics of the TCP 3-way handshake, zero-copy packet processing, and custom concurrency models.

Table of Contents

• Architecture
• Feature Support
• Performance Benchmarks
• Testing
• Installation and Usage

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Architecture

Isla utilizes a custom event loop designed for specific CPU topologies, bypassing generic async runtimes.

Hybrid Engine (Auto-Scaling)

• Single-Threaded Mode: On single-core hardware, it executes a zero-copy spin-loop to eliminate synchronization overhead.
• Sharded Multi-Threaded Mode: On multi-core systems, it spawns worker threads, distributing traffic based on a 2-tuple hash (SrcIP, SrcPort) % workers.

Adaptive Backoff

To manage CPU utilization, the main loop implements a state machine:

1. Spin: Polling for high-load bursts.
2. Yield: Relinquishing CPU time.
3. Sleep: Micro-sleep (50µs) during low activity.

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Feature Support

Layer	Protocol	Status
L2	Ethernet	Implemented
L2	ARP	Implemented
L3	IPv4	Header validation only
L3	IPv6	Core parsing, Hop Limits
L3	ICMP	Echo Request/Reply
L3	ICMPv6	Echo Reply, NDP
L4	TCP	3-Way Handshake, PSH, FIN, RST
L4	UDP	Pseudo-header checksum
L7	DHCP	DORA Sequence
L7	DNS	Basic A-Record Query
L7	HTTP	Static HTML responder

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Performance Benchmarks

Note: Results obtained on an Intel Celeron 900 (2.2GHz, 2009) using a local TAP interface.

Metric	Result
Throughput	3,109 Req/Sec
Latency	< 1ms
Concurrency	100 Concurrent

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Testing

Isla maintains a rigorous testing suite:

• Unit Tests: Integrated unit tests for all modules (arp, ipv6, tcp, udp, etc.).
• Integration Testing: A Python-based suite (test_stack.py) validates the stack against real-world scenarios.

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Installation and Usage

Prerequisites

• Linux Kernel (TAP device creation required)
• Rust (Cargo)
• Root/Sudo privileges

Quick Start

1. Build:

   cargo build --release

2. Setup:

   sudo ip tuntap add mode tap user $USER name isla0
   sudo ip link set isla0 up
   sudo ip addr add 192.168.1.1/24 dev isla0

3. Run:

   ./target/release/isla

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Built with 🦀 & 🐍 by Seuriin