This module provides types and useful methods for working with IPv4 and IPv6 network addresses, commonly called IP prefixes. The new IpNet, Ipv4Net, and Ipv6Net types build on the existing IpAddr, Ipv4Addr, and Ipv6Addr types already provided in Rust's standard library and align to their design to stay consistent.

The module also provides the IpSubnets, Ipv4Subnets, and Ipv6Subnets types for iterating over the subnets contained in an IP address range. The IpAddrRange, Ipv4AddrRange, and Ipv6AddrRange types for iterating over IP addresses in a range. And traits that extend Ipv4Addr and Ipv6Addr with methods for addition, subtraction, bitwise-and, and bitwise-or operations that are missing in Rust's standard library.

The module only uses stable features so it is guaranteed to compile using the stable toolchain. Tests aim for thorough coverage and can be found in both the test modules and doctests. Please file an issue on GitHub if you have any problems, requests, or suggested improvements.

Read the documentation for the full details. And find it on Crates.io.

Release 2.0 requirements

Release 2.0 requires Rust 1.26 or later. Release 1.0 used a custom emulated 128-bit integer type (Emu128) to fully support IPv6 addresses. This has been replaced with Rust's built-in 128-bit integer, which is now stable as of Rust 1.26. There are reports of issues using Rust's 128-bit integers on some targets (e.g. Emscripten). If you have issues on your chosen target, please continue to use the 1.0 release until that has been resolved.

Examples

Create a network address and print the hostmask and netmask

extern crate ipnet;
use std::net::{Ipv4Addr, Ipv6Addr};
use std::str::FromStr;
use ipnet::{IpNet, Ipv4Net, Ipv6Net};

fn main() {
    // Create an Ipv4Net and Ipv6Net from their constructors.

    let net4 = Ipv4Net::new(Ipv4Addr::new(10, 1, 1, 0), 24).unwrap();
    let net6 = Ipv6Net::new(Ipv6Addr::new(0xfd, 0, 0, 0, 0, 0, 0, 0), 24).unwrap();

    // They can also be created from string representations.

    let net4 = Ipv4Net::from_str("10.1.1.0/24").unwrap();
    let net6 = Ipv6Net::from_str("fd00::/24").unwrap();

    // Or alternatively as follows.
    
    let net4: Ipv4Net = "10.1.1.0/24".parse().unwrap();
    let net6: Ipv6Net = "fd00::/24".parse().unwrap();

    // IpNet can represent either an IPv4 or IPv6 network address.

    let net = IpNet::from(net4);
    
    // It can also be created from string representations.

    let net = IpNet::from_str("10.1.1.0/24").unwrap();
    let net: IpNet = "10.1.1.0/24".parse().unwrap();

    // There are a number of methods that can be used. Read the
    // documentation for the full details.

    println!("{} hostmask = {}", net, net.hostmask());
    println!("{} netmask = {}", net4, net4.netmask());
}

Subdivide an existing IP network into smaller subnets

extern crate ipnet;
use ipnet::Ipv4Net;

fn main() {
    let net: Ipv4Net = "192.168.0.0/23".parse().unwrap();

    println!("\n/25 subnets in {}:", net);

    // Note: `subnets()` returns a `Result`. If the given prefix length
    // is less than the existing prefix length the `Result` will contain
    // an error.

    let subnets = net.subnets(25)
        .expect("PrefixLenError: new prefix length cannot be shorter than existing");

    // Output:
    //  subnet 0 = 192.168.0.0/25
    //  subnet 1 = 192.168.0.128/25
    //  subnet 2 = 192.168.1.0/25
    //  subnet 3 = 192.168.1.128/25

    for (i, n) in subnets.enumerate() {
        println!("\tsubnet {} = {}", i, n);
    }
}

Iterate over the valid subnets between two IPv4 addresses

extern crate ipnet;
use std::net::Ipv4Addr;
use ipnet::Ipv4Subnets;

fn main() {
    let start = Ipv4Addr::new(10, 0, 0, 0);
    let end = Ipv4Addr::new(10, 0, 0, 239);

    println!("\n/0 or greater subnets between {} and {}:", start, end);

    // Output all subnets starting with the largest that will fit. This
    // will give us the smallest possible set of valid subnets.
    //
    // Output:
    //  subnet 0 = 10.0.0.0/25
    //  subnet 1 = 10.0.0.128/26
    //  subnet 2 = 10.0.0.192/27
    //  subnet 3 = 10.0.0.224/28

    let subnets = Ipv4Subnets::new(start, end, 0);

    for (i, n) in subnets.enumerate() {
        println!("\tsubnet {} = {}", i, n);
    }

    println!("\n/26 or greater subnets between {} and {}:", start, end);

    // Output all subnets with prefix lengths less than or equal to 26.
    // This results in more subnets, but limits them to a maximum size.
    //
    // Output:
    //  subnet 0 = 10.0.0.0/26
    //  subnet 1 = 10.0.0.64/26
    //  subnet 2 = 10.0.0.128/26
    //  subnet 3 = 10.0.0.192/27
    //  subnet 4 = 10.0.0.224/28

    let subnets = Ipv4Subnets::new(start, end, 26);

    for (i, n) in subnets.enumerate() {
        println!("\tsubnet {} = {}", i, n);
    }
}

Aggregate a list of IP prefixes

extern crate ipnet;
use ipnet::IpNet;

fn main() {}
    // Example input list of overlapping and adjacent prefixes.

    let strings = vec![
        "10.0.0.0/24", "10.0.1.0/24", "10.0.1.1/24", "10.0.1.2/24",
        "10.0.2.0/24",
        "10.1.0.0/24", "10.1.1.0/24",
        "192.168.0.0/24", "192.168.1.0/24", "192.168.2.0/24", "192.168.3.0/24",
        "fd00::/32", "fd00:1::/32",
    ];

    let nets: Vec<IpNet> = strings.iter().filter_map(|p| p.parse().ok()).collect();
    
    println!("\nAggregated IP prefixes:");
    
    // Output:
    //  10.0.0.0/23
    //  10.0.2.0/24
    //  10.1.0.0/23
    //  192.168.0.0/22
    //  fd00::/31
    
    for n in IpNet::aggregate(&nets) {
        println!("\t{}", n);
    }
}

Future

• Implementing std::ops::{Add, Sub, BitAnd, BitOr} for Ipv4Addr and Ipv6Addr would be useful as these are common operations on IP addresses. If done, the extension traits provided in this module would be removed and the major version incremented. Implementing these requires a change to the standard library. I've started a thread on this topic on the Rust Internals discussion board.
• The results of hosts() and potentially subnets() should be represented as a Range rather than the custom IpAddrRange and IpSubnets types provided in this module. This requires the target types to have Add and Step implemented for them. Implementing Add for IpAddr, Ipv4Addr, and Ipv6Addr requires a change to the standard library (see above). And Step is still unstable so exploring this will also wait until it has stablized.

License

Copyright (c) 2017, Juniper Networks, Inc. All rights reserved.

This code is licensed to you under either the MIT License or Apache License, Version 2.0 at your choice (the "License"). You may not use this code except in compliance with the License. This code is not an official Juniper product. You can obtain a copy of the License at: https://opensource.org/licenses/MIT or http://www.apache.org/licenses/LICENSE-2.0