DHCPv6: Prefix exclude option can be 17 octets

[rsmarples]

Well that's a simple off by one error

Reported-by: CuB3y0nd root@cubeyond.net

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 6ca25edf-926d-4895-8672-663f885d938e

📥 Commits

Reviewing files that changed from the base of the PR and between 708b4a5 and 04f00a0.

📒 Files selected for processing (1)

• src/dhcp6.c

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Walkthrough

In src/dhcp6.c, the temporary buffer exb used to construct the D6_OPTION_PD_EXCLUDE option within dhcp6_makemessage is resized from 16 bytes to 17 bytes. The local declaration is also adjusted to include an additional helper variable alongside the buffer.

Changes

DHCPv6 PD Exclude Option Buffer Fix

Layer / File(s)	Summary
Resize exb buffer for PD exclude packing src/dhcp6.c	Buffer exb in dhcp6_makemessage increased from 16 to 17 bytes; local declaration updated to include an extra helper variable used during D6_OPTION_PD_EXCLUDE option construction.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: fixing the DHCPv6 Prefix Exclude option to allow 17 octets instead of 16, directly addressing the off-by-one error.
Description check	✅ Passed	The description is relevant to the changeset, clearly identifying the issue as an off-by-one error with appropriate credit to the reporter.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch pd_exclude

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