Crate getifs 

GetIfs

Cross-platform enumeration of network interfaces and their MTU, gateway, multicast, and local/private/public IP addresses — with a libc-free netlink backend on Linux and no getifaddrs dependency.

Installation

[dependencies]
getifs = "0.5"

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 189x 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

OS	Approach
Linux (no libc)	socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE)
BSD-like	sysctl
Windows	GetAdaptersAddresses

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 189x faster on macOS (interface_by_index)
  • Up to 37x faster on macOS (list interfaces)
  • 2.4–2.8x faster on Linux (interface enumeration)
  • ~7x faster local-IP lookup on Linux
  • Comparable performance on Windows (GetAdaptersAddresses 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

Numbers below compare getifs against network-interface 2 and local-ip-address 0.6. Each row reports median cargo bench time (Criterion, 100 samples).

• macOS (Apple M4 Pro) — measured on a bare-metal laptop, not CI. The GitHub Actions macOS runners are shared virtual machines with highly variable latency (run-to-run wobble of ±30% on these ops), which obscures the real cost difference.
• Linux (x64) / Windows (x64) — measured on GitHub Actions ubuntu-latest / windows-latest runners on 2026-04-15 03:34 UTC.

Platform	Best Operation	getifs	Alternative	Speedup
macOS (Apple M4 Pro)	Get interface by index	1.7 μs	314.2 μs	189x faster
macOS (Apple M4 Pro)	List all interfaces	8.4 μs	313.0 μs	37x faster
Linux (x64)	Local IPv4 lookup	13.7 μs	94.3 μs	6.9x faster
Linux (x64)	List all interfaces	41.5 μs	111.7 μs	2.7x faster
Windows (x64)	Gateway IPv4	30.2 μs	N/A	Unique feature

Detailed Results

Interface Operations

macOS (Apple M4 Pro, 24 GB, local bare-metal)

Operation	getifs	Alternative	Speedup
List all interfaces	8.4 μs	313.0 μs (network-interface)	37x faster
Get interface by index	1.7 μs	314.2 μs (network-interface)	189x faster
Get interface by name	10.4 μs	314.1 μs (network-interface)	30x faster
Get interface addresses	8.4 μs	-	-
Get multicast addresses	2.9 μs	-	-

Linux (GitHub Actions x64)

Operation	getifs	Alternative	Speedup
List all interfaces	41.5 μs	111.7 μs (network-interface)	2.7x faster
Get interface by index	40.3 μs	111.9 μs (network-interface)	2.8x faster
Get interface by name	46.1 μs	111.9 μs (network-interface)	2.4x faster
Get interface addresses	17.3 μs	-	-
Get multicast addresses	31.4 μs	-	-

Windows (GitHub Actions x64)

Operation	getifs	Alternative	Notes
List all interfaces	974 μs	967 μs (network-interface)	Within noise
Get interface by index	954 μs	976 μs (network-interface)	Within noise
Get interface by name	1011 μs	969 μs (network-interface)	Within noise
Get interface addresses	958 μs	-	-
Get multicast addresses	966 μs	-	-

Note: the Win32 GetAdaptersAddresses API has an inherent ~1 ms floor that dominates every implementation — getifs and network-interface end up within measurement noise of each other on Windows.

Local IP Address Operations

macOS (Apple M4 Pro, 24 GB, local bare-metal)

Operation	getifs	Alternative	Speedup
Get local IPv4 address	6.5 μs	9.8 μs (local-ip-address)	1.5x faster
Get local IPv6 address	7.9 μs	9.8 μs (local-ip-address)	1.2x faster

Linux (GitHub Actions x64)

Operation	getifs	Alternative	Speedup
Get local IPv4 address	13.7 μs	94.3 μs (local-ip-address)	6.9x faster
Get local IPv6 address	11.2 μs	-	No IPv6 result from alternative

Windows (GitHub Actions x64)

Operation	getifs	Alternative	Notes
Get local IPv4 address	963 μs	919 μs (local-ip-address)	Win32 ~1 ms floor
Get local IPv6 address	992 μs	972 μs (local-ip-address)	Win32 ~1 ms floor

Gateway Operations

Platform	IPv4 Gateways	IPv6 Gateways	All Gateways
macOS (M4 Pro, local)	17.5 μs	2.4 μs	19.8 μs
Linux (x64, CI)	18.4 μs	14.3 μs	22.4 μs
Windows (x64, CI)	30.2 μs	18.0 μs	48.5 μs

Note: No direct alternatives available for gateway discovery, so these are reported as absolute times rather than as speedups.

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 (30–189x on bare metal) due to the efficient sysctl-based implementation avoiding getifaddrs’s per-call overhead. On shared CI runners the absolute numbers are noisier but the ordering holds.
• Linux: 2.4–2.8x faster interface enumeration via direct netlink, and ~7x faster local-IP lookup from avoiding the test-socket round trip that local-ip-address performs.
• Windows: Similar performance to alternatives — GetAdaptersAddresses has an inherent ~1 ms floor that dominates every implementation.

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) 2026 Al Liu.

Re-exports

pub use ipnet;

Modules

probe

IP protocol probing

rfc

Known RFCs for IP addresses

Structs

Flags

Flags represents the interface flags.

Ifv4Addr

An interface IPv4 address.

Ifv4Net

An interface IPv4 network.

Ifv6Addr

An interface IPv6 address.

Ifv6Net

An interface IPv6 network.

Interface

The interface struct

MacAddr

Represents a physical hardware address (MAC address).

SmolStr

A SmolStr is a string type that has the following properties:

Enums

IfAddr

An interface address.

IfNet

An interface network.

Functions

best_local_addrs

Returns both IPv4 and IPv6 addresses from the interfaces with the best default routes. The “best” interfaces are determined by the routing metrics of default routes.

best_local_ipv4_addrs

Returns the IPv4 addresses from the interface with the best default route. The “best” interface is determined by the routing metrics of default routes (0.0.0.0).

best_local_ipv6_addrs

Returns the IPv6 addresses from the interface with the best default route. The “best” interface is determined by the routing metrics of default routes (::).

gateway_addrs

Returns all gateway IP addresses (both IPv4 and IPv6) configured on the system. Only returns addresses from interfaces that have valid routes and excludes any addresses that are not configured as gateways.

gateway_addrs_by_filter

Returns all gateway IP addresses (both IPv4 and IPv6) configured on the system that match the given filter. Only returns addresses from interfaces that have valid routes and excludes any addresses that are not configured as gateways.

gateway_ipv4_addrs

Returns all IPv4 gateway addresses configured on the system. Only returns addresses from interfaces that have valid routes and excludes any addresses that are not configured as gateways.

gateway_ipv4_addrs_by_filter

Returns all IPv4 gateway addresses configured on the system that match the given filter. Only returns addresses from interfaces that have valid routes and excludes any addresses that are not configured as gateways.

gateway_ipv6_addrs

Returns all IPv6 gateway addresses configured on the system. Only returns addresses from interfaces that have valid routes and excludes any addresses that are not configured as gateways.

gateway_ipv6_addrs_by_filter

Returns all IPv6 gateway addresses configured on the system that match the given filter. Only returns addresses from interfaces that have valid routes and excludes any addresses that are not configured as gateways.

get_ip_mtu

Get the MTU of the given IpAddr.

get_ipv4_mtu

Get the MTU of the given Ipv4Addr.

get_ipv6_mtu

Get the MTU of the given Ipv6Addr.

ifindex_to_name

Returns the name of the interface by the given index.

ifname_to_iface

Returns the IPv6 interface of by the given name.

ifname_to_index

Returns the index of the interface by the given name.

ifname_to_v4_iface

Returns the IPv4 interface of by the given name.

ifname_to_v6_iface

Returns the IPv6 interface of by the given name.

interface_addrs

Returns a list of the system’s unicast interface addrs.

interface_addrs_by_filter

Returns a list of the system’s unicast interface addrs.

interface_by_index

Returns the interface specified by index.

interface_by_name

Returns the interface specified by name.

interface_ipv4_addrs

Returns a list of the system’s unicast, IPv4 interface addrs.

interface_ipv4_addrs_by_filter

Returns a list of the system’s unicast, IPv4 interface addrs.

interface_ipv6_addrs

Returns a list of the system’s unicast, IPv6 interface addrs.

interface_ipv6_addrs_by_filter

Returns a list of the system’s unicast, IPv6 interface addrs.

interface_multicast_addrsApple or FreeBSD or Linux or Windows

Returns a list of the system’s multicast interface addrs.

interface_multicast_addrs_by_filterApple or FreeBSD or Linux or Windows

Returns a list of the system’s multicast interface addrs. The filter is used to determine which multicast addresses to include.

interface_multicast_ipv4_addrsApple or FreeBSD or Linux or Windows

Returns a list of the system’s multicast, IPv4 interface addrs.

interface_multicast_ipv4_addrs_by_filterApple or FreeBSD or Linux or Windows

Returns a list of the system’s multicast, IPv4 interface addrs. The filter is used to determine which multicast addresses to include.

interface_multicast_ipv6_addrsApple or FreeBSD or Linux or Windows

Returns a list of the system’s multicast, IPv6 interface addrs.

interface_multicast_ipv6_addrs_by_filterApple or FreeBSD or Linux or Windows

Returns a list of the system’s multicast, IPv6 interface addrs. The filter is used to determine which multicast addresses to include.

interfaces

Returns a list of the system’s network interfaces.

local_addrs

Returns all IP addresses (both IPv4 and IPv6) from interfaces that have valid routes (excluding loopback). This ensures we only return addresses that can be used for communication.

local_addrs_by_filter

Returns all IP addresses (both IPv4 and IPv6) from interfaces that have valid routes.

local_ipv4_addrs

Returns all IPv4 addresses from interfaces that have valid routes (excluding loopback). This ensures we only return addresses that can be used for communication.

local_ipv4_addrs_by_filter

Returns all IPv4 addresses from interfaces that have valid routes.

local_ipv6_addrs

Returns all IPv6 addresses from interfaces that have valid routes (excluding loopback). This ensures we only return addresses that can be used for communication.

local_ipv6_addrs_by_filter

Returns all IPv6 addresses from interfaces that have valid routes.

private_addrs

Returns all IP addresses that are part of RFC 6890 (regardless of whether or not there is a default route, unlike public_addrs).

private_addrs_by_filter

Returns all IP addresses that are part of RFC 6890 (regardless of whether or not there is a default route, unlike public_addrs_by_filter).

private_ipv4_addrs

Returns all IPv4 addresses that are part of RFC 6890 (regardless of whether or not there is a default route, unlike public_ipv4_addrs).

private_ipv4_addrs_by_filter

Returns all IPv4 addresses that are part of RFC 6890 (regardless of whether or not there is a default route, unlike public_ipv4_addrs_by_filter).

private_ipv6_addrs

Returns all IPv6 addresses that are part of RFC 6890 (regardless of whether or not there is a default route, unlike public_ipv6_addrs).

private_ipv6_addrs_by_filter

Returns all IPv6 addresses that are part of RFC 6890 (regardless of whether or not there is a default route, unlike public_ipv6_addrs_by_filter).

public_addrs

Returns all IP addresses that are NOT part of RFC 6890 (regardless of whether or not there is a default route, unlike private_addrs).

public_addrs_by_filter

Returns all IP addresses that are NOT part of RFC 6890 (regardless of whether or not there is a default route, unlike private_addrs_by_filter).

public_ipv4_addrs

Returns all IPv4 addresses that are NOT part of RFC 6890 (regardless of whether or not there is a default route, unlike private_ipv4_addrs).

public_ipv4_addrs_by_filter

Returns all IP addresses that are NOT part of RFC 6890 (regardless of whether or not there is a default route, unlike private_ipv4_addrs_by_filter).

public_ipv6_addrs

Returns all IPv6 addresses that are NOT part of RFC 6890 (regardless of whether or not there is a default route, unlike private_ipv6_addrs).

public_ipv6_addrs_by_filter

Returns all IPv6 addresses that are NOT part of RFC 6890 (regardless of whether or not there is a default route, unlike private_ipv6_addrs_by_filter).

Type Aliases

ParseMacAddrError

Represents an error that occurred while parsing MacAddr.