Fix encoding of Target="."

[rthellend]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @rthellend, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a subtle but important encoding bug within the DNS HTTPS record type. By correctly handling trailing dots in the Target field, it ensures that domain names, especially those representing the root or ending with a dot, are properly serialized into their byte representation, preventing potential parsing errors or misinterpretations by DNS resolvers.

Highlights

• DNS HTTPS Record Encoding: The pull request fixes an issue with the encoding of the Target field for HTTPS DNS records, specifically addressing cases where the target might end with a dot.
• Trailing Dot Handling: A strings.TrimSuffix call has been added to remove any trailing dots from the Target field before it is split into labels for encoding, ensuring correct byte representation.

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[gemini-code-assist]

Code Review

This pull request correctly fixes a bug in the serialization of the Target field for HTTPS resource records. The change prevents incorrect encoding of root (.) or fully qualified domain names. While the fix is correct for HTTPS records, I've pointed out that other parts of the serialization logic for other record types in the same function appear to have the same underlying bug. I've recommended applying this fix consistently to improve the overall robustness of the DNS message serialization.