(17b) net: model the optional LLDP TLVs

[daniel-noland]

Native LLDP for the gateway. The dataplane owns its NICs, so nothing else can speak LLDP for them, and lldpd/lldpad are hostile to automation. LLDP itself is small, so the dataplane transmits and receives it.

This used to be one PR. It is now a stack of seven, each building on the one before:

• (17a) (17a) net: LLDP TLV framing and the mandatory TLVs #1906 net: TLV framing and the mandatory TLVs
• (17b) (17b) net: model the optional LLDP TLVs #1920 net: the optional TLVs ← this PR
• (17c) (17c) net: assemble LLDP data units and decode them in Headers::parse #1921 net: the LLDPDU and Headers::parse
• (17d) (17d) lldp: the transmitter and the neighbour table #1922 lldp: the transmitter and the neighbour table
• (17e) (17e) dataplane: advertise the gateway with LLDP on every port #1923 dataplane: advertise on every port
• (17f) (17f) dataplane: hear LLDP neighbours and show them #1924 dataplane: hear neighbours, show lldp neighbors, all-multicast
• (17g) (17g) lldp: fast start, shutdown ordering, and a required datapath namespace #1925 fast start, shutdown ordering, required datapath namespace

Stacked on (16) #1905, capture. (18) #1907, rate limiting, and (19) #1919, traffic protection, build on top.

This PR: the optional TLVs

The second of three PRs adding net::lldp: the TLVs that may follow the mandatory three.

• Port description, system name and system description (Text).
• System capabilities. Reserved bits are preserved, not masked.
• Management address, with its interface numbering and OID.
• Organizationally specific TLVs, with the IEEE 802.1 port VLAN ID and VLAN name, and the IEEE 802.3 link aggregation and max frame size subtypes modelled.

Anything not modelled round-trips verbatim: unknown TLV types, OUIs and subtypes. The escape hatches for unmodelled TLVs refuse anything that has a structured representation, which keeps the mapping between octets and values one to one.

Testing

Property tests per TLV, as in the first PR.

🤖 Generated with Claude Code

[coderabbitai]

Important

Draft PR not reviewed

Draft PRs are not automatically reviewed by default.

• Trigger a manual review

To automatically review draft PRs, update your CodeRabbit configuration:

reviews:
  auto_review:
    drafts: true

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

_{Comment @coderabbitai help to get the list of available commands.}

[codecov]

Codecov Report

❌ Patch coverage is 87.18220% with 121 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
net/src/lldp/org.rs	84.77%	55 Missing and 3 partials ⚠️
net/src/lldp/management.rs	85.31%	35 Missing and 2 partials ⚠️
net/src/lldp/capabilities.rs	88.69%	13 Missing ⚠️
net/src/lldp/optional.rs	93.51%	12 Missing ⚠️
net/src/lldp/tlv.rs	90.90%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!