Enable LLDP-MED for DPUs

[stoo-davies]

Adds code to forge-dpu-agent to do two things..

1. Enable LLDP-MED in the /etc/defaults/lldp file
2. Removes the interface restriction that was preventing it from running on the management interface.

These changes are for automated cable validation.

Related issues

#3204

Type of Change

• Add - New feature or capability
• Change - Changes in existing functionality
• Fix - Bug fixes
• Remove - Removed features or deprecated functionality
• Internal - Internal changes (refactoring, tests, docs, etc.)

Breaking Changes

• This PR contains breaking changes

Testing

• Unit tests added/updated
• Integration tests added/updated
• Manual testing performed
• No testing required (docs, internal refactor, etc.)

Additional Notes

Tested on a BF3.

[coderabbitai]

Summary by CodeRabbit

• New Features

  • Improved LLDP initialization during DPU-OS startup.
  • Automatically applies LLDP configuration and enables LLDP-MED inventory.
  • Added bounded retries and timeouts for LLDP commands and service restarts.
  • Added default LLDP configuration files for supported deployments.

• Bug Fixes

  • Improved handling of missing or existing DAEMON_ARGS settings, including CRLF-formatted files.
  • Added clearer failure handling when LLDP configuration commands time out or fail.

• Tests

  • Expanded coverage for LLDP configuration updates, parsing, and default file contents.

Walkthrough

LLDP preparation now configures lldpd, verifies LLDP-MED inventory with bounded retries, and runs during DPU-OS startup before asynchronously updating the LLDP system description.

Changes

LLDP preparation

Layer / File(s)	Summary
LLDP configuration preparation crates/agent/src/lldp.rs, crates/dpf/src/flavor.rs	Adds prepare_lldp(), disables the active interface configuration, rewrites DAEMON_ARGS with newline handling, and adds fixed LLDPd configuration overrides with updated tests.
LLDP-MED verification and restart retries crates/agent/src/lldp.rs	Queries LLDP-MED configuration through bounded asynchronous lldpcli execution, restarts lldpd when necessary, and applies bounded retry delays and failure handling.
Asynchronous system description and startup wiring crates/agent/src/lldp.rs, crates/agent/src/main_loop.rs	Makes system-description updates and daemon reads asynchronous, and runs preparation separately during DPU-OS startup with independent error logging. Unit tests cover argument rewriting and inventory parsing.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Sequence Diagram(s)

sequenceDiagram
  participant setup_and_run
  participant prepare_lldp
  participant lldpcli
  participant systemctl
  setup_and_run->>prepare_lldp: prepare_lldp()
  prepare_lldp->>lldpcli: Query LLDP-MED configuration
  lldpcli-->>prepare_lldp: Configuration JSON
  prepare_lldp->>systemctl: Restart lldpd.service when required
  systemctl-->>prepare_lldp: Restart result
  prepare_lldp-->>setup_and_run: Preparation result

Loading

🚥 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 matches the main change: enabling LLDP-MED for DPUs.
Description check	✅ Passed	The description is directly related to the LLDP-MED and interface-configuration changes in this PR.
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.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/agent/src/lldp.rs`:
- Around line 81-103: Extract the configuration line-rewrite logic into a pure
helper and the inventory JSON value parsing into another pure helper, replacing
direct filesystem and command coupling in the tested paths. Add table-driven
tests using value_scenarios! and scenarios! covering absent and existing
DAEMON_ARGS, LF, CRLF, and missing-final-newline inputs, plus yes, no, missing,
and unexpected JSON values; preserve the current transformation behavior.
- Around line 119-122: Bound all LLDP-related child processes with deadlines:
update the lldpcli call in the LLDP configuration read path, the systemctl
restart path, and LldpdConfigFileWriter::daemon_read() to use timeout-capable
process handling. Ensure expired commands are terminated and reported as
retryable failures so agent startup and config-change handling cannot block
indefinitely.

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Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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📒 Files selected for processing (2)

• crates/agent/src/lldp.rs
• crates/agent/src/main_loop.rs

[wminckler]

Is there a plan to support this when DPF is used? (or does it do that already?)

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[stoo-davies]

Converting this back to draft until I can address the DPF question from @wminckler

The new code won't break anything since it's guarded by the is_dpu_os() check, however I need to get the same config applied under DPF provisioning.

[stoo-davies]

/ok to test 1520e3a

[stoo-davies]

/ok to test 175e6ad

[github-actions]

🌿 Preview your docs: https://nvidia-preview-pull-request-3692.docs.buildwithfern.com/infra-controller

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/dpf/src/flavor.rs`:
- Around line 282-297: The DPF flavor currently provisions the active
lldp-interfaces.conf that lldp::disable_interfaces_config() renames during
startup. Update the DpuFlavorConfigFiles entry for
/etc/lldpd.d/lldp-interfaces.conf to avoid provisioning an active DPF override,
or otherwise preserve the DPF-owned configuration after prepare_lldp() runs;
keep the /etc/default/lldpd entry unchanged.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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📥 Commits

Reviewing files that changed from the base of the PR and between 60023fe and 175e6ad.

📒 Files selected for processing (2)

• crates/agent/src/lldp.rs
• crates/dpf/src/flavor.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• crates/agent/src/lldp.rs