README.md

neli

Type safe netlink library for Rust

As of version 0.4.0, completeness of autogenerated documentation and examples will be a focus. Please open issues if something is missing or unclear!

API documentation

API documentation can be found here

Goals

This library aims to cover as many of the netlink subsystems as possible and provide ways to extend neli for anything that is not within the scope of support for this library.

This is also a pure Rust implementation and aims to make use of idiomatic Rust features.

Examples using neli

Examples of working code exist in the examples/ subdirectory on Github. Run cargo build --examples to build the examples.

Workflows usually follow a pattern of socket creation, and then either sending and receiving messages in request/response formats:

use std::error::Error;

use neli::{
    consts::{genl::*, nl::*, socket::*},
    err::RouterError,
    genl::{Genlmsghdr, GenlmsghdrBuilder, Nlattr},
    nl::{NlmsghdrBuilder, NlPayload},
    router::synchronous::NlRouter,
    types::{Buffer, GenlBuffer},
    utils::Groups,
};

const GENL_VERSION: u8 = 1;

fn request_response() -> Result<(), Box<dyn Error>> {
    let (socket, _) = NlRouter::connect(
        NlFamily::Generic,
        None,
        Groups::empty(),
    )?;

    let recv = socket.send::<_, _, NlTypeWrapper, Genlmsghdr<CtrlCmd, CtrlAttr>>(
        GenlId::Ctrl,
        NlmF::DUMP,
        NlPayload::Payload(
            GenlmsghdrBuilder::<_, CtrlAttr, _>::default()
                .cmd(CtrlCmd::Getfamily)
                .version(GENL_VERSION)
                .build()?
        ),
    )?;
    
    for msg in recv {
        let msg = msg?;
        // Do things with response here...
    }
    
    Ok(())
}

or a subscriptions to a stream of event notifications from netlink:

use std::error::Error;

use neli::{
    consts::{genl::*, nl::*, socket::*},
    err::RouterError,
    genl::Genlmsghdr,
    router::synchronous::NlRouter,
    utils::Groups,
};

fn subscribe_to_mcast() -> Result<(), Box<dyn Error>> {
    let (s, multicast) = NlRouter::connect(
        NlFamily::Generic,
        None,
        Groups::empty(),
    )?;
    let id = s.resolve_nl_mcast_group(
        "my_family_name",
        "my_multicast_group_name",
    )?;
    s.add_mcast_membership(Groups::new_groups(&[id]))?;
    for next in multicast {
        // Do stuff here with parsed packets...
    
        // like printing a debug representation of them:
        println!("{:?}", next?);
    }

    Ok(())
}

Contributing

Your contribution will be licensed under neli's license. I want to keep this aspect as simple as possible so please read over the license file prior to contributing to make sure that you feel comfortable with your contributions being released under the BSD 3-Clause License.

Please add tests for new features wherever possible. I may request this prior to merge if I see it is possible and missing.

Please document new features not just at a lower level but also with //! comments at the module for high level documentation and overview of the feature.

Before submitting PRs, take a look at the module's documentation that you are changing. I am currently in the process of adding a "Design decision" section to each module. If you are wondering why I did something the way I did, it should be there. That way, if you have a better way to do it, please let me know! I'm always happy to learn. My hope is that this will also clarify some questions beforehand about why I did things the way I did and will make your life as a contributer easier.

Git hooks

I've provided git hooks to simulate a subset of what CI is running. If you'd like to enable these, they'll probably catch some errors before having to look at CI. If you'd like to enable these, run git config core.hookspath .githooks. Your commits will be checked before the commit is created.

PR target branch

Steps for a PR:

• For bug fixes and improvements that are not breaking changes, please target main.
• For breaking changes, please target the branch for the next version release - this will look like v[NEXT_VERSION]-dev
• Please include a brief description of your change in the CHANGELOG file
• Once a PR has been reviewed and approved, please rebase onto the target branch
  • For those less familiar with git, it should look something like this
    • git rebase [TARGET_BRANCH] [YOUR_BRANCH]
    • This is a destructive operation so make sure you check carefully before doing this: git push -f origin [YOUR_BRANCH]