Nearing 1.0 release, feedback and code reviews are very welcome. Open an issue or comment here on the Reddit post.

This module provides types and methods for working with IPv4 and IPv6 network addresses, commonly called IP prefixes. It only uses stable Rust features so that it compiles using the stable toolchain. And its design aligns to the existing IpAddr, Ipv4Addr, and Ipv6Addr types provided in the Rust standard library.

The module includes extension traits to provide Add, Sub, BitAnd, and BitOr operations to Ipv4Addr and Ipv6Addr.

Available on [Crates.io] and read the [documentation] for the full details.

Open Questions:

• Should IpNet::new() truncate the input IpAddr to prefix_len and store that instead of the original unmodified address? Users may expect one behavior over the other. Truncating it at creation time means that the provided address cannot be returned later if the user has a need for it. Also, sort behavior will not be influence by it, e.g. 10.1.1.1/24 and 10.1.1.2/24 would be the same. There is a trunc() method that does this after creation, but chaining IpNet::new(...).trunc() or IpNet::from().unwrap().trunc() is tedious. Perhaps this should be solved with a second new_with_trunc() constructor. Or perhaps a series of builder methods?
• Should prefix_len be it's own type? This seems like newtype overload, but the API guidelines would tend to indicate it should be.
• The guidelines suggest subnets() and hosts() should return types called Subnets and Hosts respectively rather than the generic IpNetIter<T> they currently return. See here.

Future

• Some of the proposals to support default arguments would be useful for solving the truncation question, that way the default could be to truncate, and the user can override this if they don't want that behaviour.
• Explore representing the results of methods such as hosts() and subnets() as Ranges. This requires both the Add and Step traits be implemented on the target types. For IpAddr this requires a change to the standard library. Step is still unstable, so exploring this must wait until it has stablized.
• Implementing the {Add, Sub, BitAnd, BitOr} traits for Ipv4Addr and Ipv6Addr would be useful as these are common operations on IP addresses. This requires a change to the standard library. I've started a thread on this topic over on Rust Internals discussion board.

Legal

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

This code is licensed to you under the Apache License, Version 2.0 (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: http://www.apache.org/licenses/LICENSE-2.0