DHCP: free the state when dropping on state NONE

[rsmarples]

Fixes an issue when dhcpcd tries to release when the carrier is down.

Fixes #560

[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: e1eabe72-191a-442b-a107-61913dbcb825

📥 Commits

Reviewing files that changed from the base of the PR and between 42ff6d2 and e238855.

📒 Files selected for processing (1)

• src/dhcp.c

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Walkthrough

A single line is added to the dhcp_drop() function in src/dhcp.c. When there is no existing DHCP state, the function now calls dhcp_free(ifp) to clean up allocated resources after removing the eloop timeout and before notifying via dhcpcd_dropped().

Changes

Cohort / File(s)	Summary
DHCP state cleanup src/dhcp.c	Added dhcp_free(ifp) call in dhcp_drop() when DHCP state is absent to ensure proper resource deallocation.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: freeing DHCP state when dropping on state NONE, which directly addresses the linked issue.
Description check	✅ Passed	The description is directly related to the changeset, explaining that it fixes an issue with dhcpcd release operations when the carrier is down.
Linked Issues check	✅ Passed	The code change implements the required fix from issue #560 by freeing DHCP state in dhcp_drop() when state is NONE, preventing hangs during release with carrier down.
Out of Scope Changes check	✅ Passed	All changes in src/dhcp.c are directly related to the linked issue #560, with no extraneous modifications detected.

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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 dhcp_free

📝 Coding Plan

• Generate coding plan for human review comments

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