Implement checksums properly in dataplane

[shaneutt]

Problem Statement

We currently don't handle checksums properly or at all in several places. The purpose of this task is to get that sorted out.

Acceptance Criteria

• find all the places we are currently handling, or NOT handling L3 and L4 checksums and get them consistent
• use helpers like bpf_l3_cksum_replace to properly recalculate checksums

[astoycos]

Opening this up as a good issue for newcomers interested in getting involved in the ebpf dataplane bits :)

[LCaparelli]

Would like to work on this one o/

[astoycos]

@LCaparelli I would recommend joining the AYA discord If you're going to dive in here -> https://aya-rs.dev/community/

I already asked how to fix this bug here https://discord.com/channels/855676609003651072/1039654899408982077

[LCaparelli]

Yup, the nice folks over there already gave me a hand on the other issue I'm working on to improve the build process, thanks for the heads up @astoycos

[shaneutt]

@LCaparelli as I understand it you may not have time for this one going forward so I'm opening it back up, however if you still want to take this one on please just let us know! 🖖

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/lifecycle stale

[shaneutt]

Not stale, we still intend this for the v0.7.0 milestone:

/remove-lifecycle stale

However, I suspect @LCaparelli is no longer working on this (do correct me if you still wanted this)? So I think we're back to help wanted.

/help

[k8s-ci-robot]

@shaneutt:
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In response to this:

Not stale, we still intend this for the v0.7.0 milestone:

/remove-lifecycle stale

However, I suspect @LCaparelli is no longer working on this (do correct me if you still wanted this)? So I think we're back to help wanted.

/help

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[maborosii]

I have some questions about this issue, I found some functions implemented with bpf_l4_cksum_replace and bpf_l3_cksum_replace like set_ipv4_dest_port and set_ipv4_ip_dst in tc_ingress module, so you mean that we should keep consistent in other module like tc_egress and etc. ?

[shaneutt]

Consistency for sure, but I also think we just have a lot of hacks in place. I removed the good-first-issue on this one some time ago because basically what we need is someone to deep dive in and suss it all out first and actually figure out exactly what is needed, and then make the patch. So just know that we're happy to support you in this one but it's a bit of a deeper dive!

[shaneutt]

@jokestax mentioned wanting to have a go at this one:

/assign @jokestax

Please do note it's kinda old, and maybe a bit crunchy, so take your time and do reach out here or on Slack if you need any support. Also when in doubt, I would highly recommend looking at what Cilium does as they are usually a good model to follow.