Refactor DNS header decoding to simplify Z bits validation and update…

[lohanidamodar]

… documentation for interoperability considerations

Summary by CodeRabbit

• Bug Fixes

  • Improved DNS header compatibility by relaxing validation to ignore reserved Z bits during decoding, reducing false decoding errors and improving interoperability.

• Tests

  • Added unit tests verifying decoding accepts non-zero and various reserved Z-bit patterns to ensure robust interoperability.

[coderabbitai]

Walkthrough

Removed runtime validation of DNS Z bits (reserved bits 4–6 of the flags field) from Header::decode. The method no longer throws for non-zero Z bits; the docblock @throws was updated to remove the Z-bit condition and an inline note now states Z bits are reserved but ignored for interoperability. Related branching and error handling for Z-bit validation were removed. Two unit tests were added to assert decoding accepts non-zero and various Z-bit patterns.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 75.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately reflects the main change: refactoring DNS header decoding to simplify Z bits validation and updating documentation.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix-validation

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