Introduction

A high-performance, cross-platform Rust library providing comprehensive network interface information without relying on libc's getifaddrs. Get interfaces, multicast addresses, local/private/public IP addresses, MTU, and gateway information with minimal overhead.

Installation

[dependencies]
getifs = "0.4"

Features

• Zero libc dependency on Linux (uses netlink directly)
• MTU information - Get interface MTU values
• Multicast addresses - Fetch multicast group memberships
• Gateway discovery - Find IPv4 and IPv6 gateway addresses
• RFC-based filtering - Filter addresses by RFC classification
• High performance - Up to 73x faster than alternatives on macOS (see benchmarks)
• Cross-platform - Linux, macOS, BSD, Windows support

Quick Start

use getifs::{interfaces, local_addrs, gateway_addrs};

// Get all network interfaces
let interfaces = interfaces().unwrap();
for interface in interfaces {
    println!("Interface: {} (index: {})", interface.name(), interface.index());
    println!("  MTU: {}", interface.mtu());
    println!("  Flags: {:?}", interface.flags());
}

// Get local IP addresses
let local_ips = local_addrs().unwrap();
for ip in local_ips {
    println!("Local IP: {}", ip);
}

// Get gateway addresses
let gateways = gateway_addrs().unwrap();
for gateway in gateways {
    println!("Gateway: {}", gateway);
}

Examples

• Fetching all interfaces: examples/interfaces.rs
• Fetching all interface addresses (excluding multicast addrs): examples/addrs.rs
• Fetching all interface multicast addresses: examples/multicast_addrs.rs
• Fetching gateway addresses: examples/gateway.rs
• Fetching local ip addresses: examples/local_ip_addrs.rs
• Fetching ip addresses by RFC: examples/filter_by_rfc.rs

Details

Why getifs?

Existing network interface crates have limitations:

• Missing features: Most don't support MTU or multicast addresses
• Performance overhead: Nearly all use libc::getifaddrs, which is slower
• Unnecessary allocations: Heavy use of heap allocations for simple queries

getifs addresses these by:

• Using platform-native APIs directly (netlink, sysctl, GetAdaptersAddresses)
• Minimizing allocations with SmallVec and SmolStr
• Providing comprehensive interface information including MTU and multicast support
• Achieving significantly better performance than alternatives:
  • Up to 73x faster on macOS (interface_by_index)
  • Up to 21x faster on macOS (list interfaces)
  • 2-3x faster on Linux
  • Comparable performance on Windows (Windows API overhead dominates)

Roadmap

• Support fetching routing tables

Benchmarks

All benchmarks are run with Criterion.rs on GitHub Actions. Lower is better.

Note: Automated benchmarks run on Linux, macOS, and Windows via GitHub Actions. View the latest results in the Actions tab or see benchmark documentation for more details.

Performance Summary

Detailed Results

Interface Operations

macOS (GitHub Actions ARM64)

Linux (GitHub Actions x64)

Windows (GitHub Actions x64)

Note: Windows API (GetAdaptersAddresses) has inherent overhead causing all operations to be ~1ms regardless of implementation.

Local IP Address Operations

macOS (GitHub Actions ARM64)

Linux (GitHub Actions x64)

Windows (GitHub Actions x64)

Gateway Operations

Note: No direct alternatives available for gateway discovery.

Why is getifs faster?

• Direct system calls: Uses platform-native APIs (netlink on Linux, sysctl on BSD/macOS, GetAdaptersAddresses on Windows)
• Zero-copy parsing: Minimal allocations and efficient buffer reuse
• No libc dependency on Linux: Direct netlink socket communication
• Optimized data structures: Uses SmallVec and SmolStr to avoid heap allocations for common cases

Platform Performance Notes:

• macOS: Shows the largest speedups (16-73x) due to efficient sysctl implementation
• Linux: Moderate speedups (2-3x) from direct netlink communication vs libc
• Windows: Similar performance to alternatives due to GetAdaptersAddresses API overhead (~1ms baseline for all implementations)

Sister crates

• iprobe: Probe if the host system supports IPv4, IPv6 and IPv4-mapped-IPv6.
• iprfc: Known RFCs for IP addresses.

Pedigree

• The code in this crate is inspired by Golang's interface.go and HashiCorp's go-sockaddr.

License

getifs is under the terms of both the MIT license and the Apache License (Version 2.0).

See LICENSE-APACHE, LICENSE-MIT for details.

Copyright (c) 2025 Al Liu.