# 8.1 The inventory

_Peios / Peios technical reference / netd / What Netd Publishes_

> What netd writes under Interfaces\<id>\Status for every interface it has seen, when each value is set or removed, the descriptor on Status, and the values netd shares with the operator.

## 8.1.1 The record [*inventory.record]

Every non-loopback interface netd has seen has a key
`Machine\System\Network\Interfaces\<id>`, named by its interface id
(§4.1). netd creates it on the first pass that sees the interface. The
key is the operator's, apart from `ClientId`, a value both write (§5.7).
netd's findings are under its `Status` subkey.

Records are never deleted. The record of a card that has been removed
stays, with what netd last wrote.

## 8.1.2 Status [*inventory.status-values]

| Value | Content | Present |
|---|---|---|
| `Name` | the kernel's name for the link | always |
| `Kind` | `wired`, `wireless` or `other` | always |
| `Mac` | the hardware address, lower-case, colon-separated | when the link has one |
| `Path` | the bus path | when there is one |
| `Driver` | the driver | when there is one |
| `Verdict` | `JOIN`, `IGNORE` or `DOWN` | when a rule spoke; removed when the backstop answered or rules tied |
| `Rule` | the path of the rule that spoke, or the tied rules as `<a> vs <b>` | when a rule spoke or rules tied; removed when the backstop answered |
| `Profile` | the profile path as written | `JOIN` only |
| `Readiness` | the interface's level (§8.2) | `JOIN` only |
| `Network` | the id of the network identified on the link now | while one is identified; removed when the carrier goes |
| `LastNetwork` | the id of the network the link last stood on | from the first identification; never removed |

[*inventory.value-presence]

Every value is `REG_SZ`. A value is written only when it differs from
what is there, and removed only when it is there, so a pass that changes
nothing writes nothing to the registry. [*inventory.writes-only-on-change]

`Status` is refreshed on every full pass for every non-loopback interface,
and again at each publish (§2.2) for joined ones, so `Readiness` follows
a reconcile that moved it without any link event.

`Status Network` is read by the kernel to give the packet layers their
`Network.*` facts (PKM §6.5). It names the network only while netd has
identified one on the link (§7.1).

## 8.1.3 The descriptor [*inventory.status-descriptor]

`Status` is created with the descriptor
`O:SYG:SYD:P(A;;KA;;;SY)(A;;KR;;;WD)`: SYSTEM has full control, Everyone
has read access, and the DACL is protected, so the hive root's inheritable grant
to Administrators does not reach it. Only netd, as SYSTEM, can write
there. An administrator's hand edit is refused at the write, not
reverted at the next pass. The descriptor is set only when netd creates
the key.

## 8.1.4 The machine's values

On `Machine\System\Network` itself netd writes:

- `Readiness`, the machine level (§8.2);
- `Duid`, when it was absent and netd generated or read one (§5.7).