ieee1722: Initial implementation of parts of IEEE 1722.

[nayakned]

AI Assisted: no for the implementation/copilot for unit tests.

• Implemented the Chapter 9 of the IEEE 1722-2025 spec.
• Added unit test cases for dissecting and generating packets belonging to this protocol

Checklist :

• Check the contribution guide at https://github.com/secdev/scapy/blob/master/CONTRIBUTING.md (esp. section submitting-pull-requests) ✅
• Have good commit hygiene. They must have the AI-Assisted tag as explained in the contributing guide. Please squash commits that belong together, and split commits that contain multiple features. ✅
• AI: You must make sure that you understood the internal concepts of Scapy and have good test coverage (like >90%). Please review ALL the code you generated. ✅
• Add unit tests or explain why they are not relevant. ✅
• If the PR is still not finished, please create a Draft Pull Request ✅
• If this PR contains more than 500 lines of code (excluding unit tests), consider splitting it. -> IEEE 1722 aka Audio/Video Transport Protocol (AVTP) specifies a large number of serialization formats over Ethernet. In this PR only the serialization formats mentioned in the Chapter 9 (these are the ones relevant for automotive usecases) are implemented. While the number of lines may seem large, the PR only has features/serialization formats belonging together.
• New protocols: I considered interoperability tests with existing packages or utilities to ensure conformity of a newly generated protocol ✅ Tested conformance along with Ethernet, UDP/IP

Description

IEEE 1722 specifies the Audio/Video Transport Protocol (AVTP) along with several serialization formats for data which can be transported over Ethernet (e.g., various audio formats, video formats etc.). The 2016 version of the specification extended the spec to also include so-called control formats including automotive fieldbus frames, e.g., CAN, LIN, FlexRay etc. Now the recent 2025 version also includes serialization formats for I2C, SPI etc.

In this PR, we focus on the AVTP control formats (the ones described in the Chapter 6 of the IEEE 1722 spec.). This is not an exhaustive implementation of IEEE 1722 as we do not focus on the audio/video formats. The reason for contributing this to the upstream project is that we see currently traction for using IEEE 1722. We (myself and a few like-minded colleagues) are working on integrating this protocol into open source projects and encourage adoption. We are also working on:

• COVESA/Open1722
• Wireshark dissector

[polybassa]

Focus on simplicity and Scapy-likeness: the protocol fields themselves are mostly fine, but ACF framing, UDP encapsulation, and duplicated post_build/extract_padding should live in the packet hierarchy once.

Main priorities from this review: ACF boundary handling → I2C length fix → UDP wrapper layer → public version classes → collapse duplicated ACF plumbing.

This review was written with the help of AI (ChatGPT).

[polybassa]

Thanks for your PR

[nayakned]

Thanks for your PR

Thanks for the exhaustive review. Got to know more about Scapy with this PR.
I have addressed most of your findings.
Perhaps where you can help me:

• Please have an explicit look at how AvtpAcfTscfHeader and AvtpAcfNtscfHeader and their versions for their "Scapyness".
• AvtpAcfI2CHeader also contains the payload. So I am toying with the idea to call it just AvtpAcfI2C. Same for the brief format.

Let me know if you have further findings or want me to rearrange the commit history.

[polybassa]

Follow-up on the latest tip (9f7e707): the structural cleanup looks good. Two concrete P1 regressions remain.

This review was written with the help of AI (ChatGPT).

[polybassa]

P3: Pass Enum classes directly.

Where code still contains:

enum={i.name: i.value for i in AncMode}

prefer:

enum=AncMode

Scapy enum fields already support Python Enum classes. This is already done correctly in several other places in the PR, so the remaining instances should be made consistent.

[nayakned]

Implemented as suggested.

[polybassa]

Thanks for the PR, just a few more comments

[nayakned]

@polybassa I have often discussed with my colleagues the best way to model the class/packets for this protocol.
Personally, I prefer to align with the specification. It is not our job to fix issues in the specification.
Therefore, I prefer to keep the packet classes AvtpCommon*, even though they will never be seen in a standalone correct system. This allows future developers to inherit or extend these classes or the IEEE 1722 module.

I hope exposing only serializable classes and making non-serializable classes (with the exception of AvtpCommonHeader) is an acceptable solution.

[polybassa]

Thanks for your work. I think we are almost there.

[polybassa]

Length check

[nayakned]

Added length checks as suggested.

[polybassa]

Please fix the AI-Assisted trailer check.

[codecov]

Codecov Report

❌ Patch coverage is 80.64516% with 60 lines in your changes missing coverage. Please review.
✅ Project coverage is 47.38%. Comparing base (7daa15d) to head (9a08caf).
⚠️ Report is 7 commits behind head on master.

Files with missing lines	Patch %	Lines
scapy/contrib/ieee1722.py	80.64%	60 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5185      +/-   ##
==========================================
+ Coverage   47.28%   47.38%   +0.10%     
==========================================
  Files         375      376       +1     
  Lines       97732    98042     +310     
==========================================
+ Hits        46209    46459     +250     
- Misses      51523    51583      +60     

Files with missing lines	Coverage Δ
scapy/contrib/ieee1722.py	80.64% <80.64%> (ø)

... and 3 files with indirect coverage changes

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