IPv4: Ignore DHCP state when building routes

[rsmarples]

As this will change periodically.
We only care if the state (address) has been added.

Fixes #440 thanks to JognSmit.

[coderabbitai]

Walkthrough

The inet_dhcproutes guard condition in src/ipv4.c was simplified from requiring both DHS_BOUND state and a non-zero added flag to only checking if the STATE_ADDED bit is set. This decouples route processing from the interface's bound state.

Changes

Cohort / File(s)	Summary
IPv4 DHCP routes guard condition src/ipv4.c	Changed inet_dhcproutes check from state->state != DHS_BOUND && !state->added to !(state->added & STATE_ADDED). Removes dependency on DHS_BOUND state; now processes routes when STATE_ADDED bit flag is set regardless of bound state.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

• Rationale for condition change: Verify that decoupling route processing from DHS_BOUND state resolves the issue without introducing unintended side effects in other renewal scenarios
• Bitwise flag semantics: Confirm STATE_ADDED bit semantics and ensure the change properly distinguishes added vs. non-added routes
• Test coverage: Check if existing tests cover DHCP renewal with multiple interfaces to prevent regression of similar race conditions

Pre-merge checks and finishing touches

❌ 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%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The PR title 'IPv4: Ignore DHCP state when building routes' clearly and accurately summarizes the main code change, which simplifies the inet_dhcproutes check condition by removing the DHS_BOUND state requirement.
Description check	✅ Passed	The PR description is related to the changeset, explaining the rationale ('We only care if the state (address) has been added') and linking to issue #440 which documents the problem being fixed.
Linked Issues check	✅ Passed	The code change addresses the root cause in issue #440: removing the DHS_BOUND check allows routes to be added/maintained based on the STATE_ADDED flag regardless of DHCP state transitions, preventing unintended route deletion during concurrent interface renewals.
Out of Scope Changes check	✅ Passed	The change is narrowly scoped to the inet_dhcproutes check condition in src/ipv4.c, modifying only the guard clause logic to match the linked issue's objective of preventing route loss during state changes.

✨ 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 dhcp-routes-added

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 9c48f4c and d25c026.

📒 Files selected for processing (1)

• src/ipv4.c (1 hunks)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (14)

• GitHub Check: netbsd (--disable-ipv6)
• GitHub Check: netbsd (--disable-ipv4, -DSMALL)
• GitHub Check: netbsd (--disable-arp)
• GitHub Check: netbsd (--disable-ipv6, -DSMALL)
• GitHub Check: netbsd (--disable-ipv4)
• GitHub Check: netbsd (--disable-arp, -DSMALL)
• GitHub Check: netbsd (--disable-dhcp6, -DSMALL)
• GitHub Check: netbsd (--disable-ipv4ll, -DSMALL)
• GitHub Check: netbsd
• GitHub Check: netbsd (--disable-dhcp6)
• GitHub Check: freebsd
• GitHub Check: netbsd (--disable-ipv4ll)
• GitHub Check: netbsd (-DSMALL)
• GitHub Check: openbsd

🔇 Additional comments (1)

src/ipv4.c (1)

294-294: LGTM! This change correctly addresses issue #440.

The simplified guard now only checks whether the address has been added (STATE_ADDED bit), removing the DHS_BOUND state requirement. This prevents route deletion during DHCP renewal state transitions (e.g., DHS_RENEWING, DHS_REBINDING), which was causing the "Network is unreachable" errors on multi-interface systems.

The bitwise check !(state->added & STATE_ADDED) is also more appropriate for the flags field and consistent with other usages throughout the code (lines 268-270, 430, 445).

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