Remote access via 0-hop neighbors

Remote maintenance allows an operator to “dial into” a device through a physically adjacent helper node (Bluetooth or USB tether), without traversing the mesh TTL.

Threat model

This feature is powerful and dangerous:

• Only enabled when local user presses MAINTENANCE_CONSENT or TTL=0 maintenance token is presented.
• Sessions are short-lived (e.g. 10 minutes).

REMOTE_SHELL payload (0x81)

Encapsulates a byte stream similar to SSH, but simplified:

Field	Size
sessionId	4
seq	2
stdinChunk	remainder

Responses use the same type with seq echoed.

Topology

Operator phone (BLE) —0-hop—> Helper handheld —USB—> Target device

The helper forwards bytes; the target exposes a REPL, CLI, or file transfer sub-shell.

Mesh not involved

Packets for remote shell never consume mesh ttl. They are link-local on the helper↔target cable or BLE bridge.

Mesh-wide operator actions (distinct from this document)

Configuration and bulletin moderation over RF use a separate admin channel and ADMIN_CMD payloads — see Mesh admin & operator channel. That path does traverse the mesh (ttl); this REMOTE_SHELL path does not.