111 lines
4.9 KiB
Markdown
111 lines
4.9 KiB
Markdown
---
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summary: "Node discovery and transports (Bonjour, Tailscale, SSH) for finding the gateway"
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read_when:
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- Implementing or changing Bonjour discovery/advertising
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- Adjusting remote connection modes (direct vs SSH)
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- Designing node discovery + pairing for remote nodes
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---
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# Discovery & transports
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Clawdbot has two distinct problems that look similar on the surface:
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1) **Operator remote control**: the macOS menu bar app controlling a gateway running elsewhere.
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2) **Node pairing**: iOS/Android (and future nodes) finding a gateway and pairing securely.
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The design goal is to keep all network discovery/advertising in the **Node Gateway** (`clawd` / `clawdbot gateway`) and keep clients (mac app, iOS) as consumers.
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## Terms
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- **Gateway**: a single long-running gateway process that owns state (sessions, pairing, node registry) and runs channels. Most setups use one per host; isolated multi-gateway setups are possible.
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- **Gateway WS (control plane)**: the WebSocket endpoint on `127.0.0.1:18789` by default; can be bound to LAN/tailnet via `gateway.bind`.
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- **Direct WS transport**: a LAN/tailnet-facing Gateway WS endpoint (no SSH).
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- **SSH transport (fallback)**: remote control by forwarding `127.0.0.1:18789` over SSH.
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- **Legacy TCP bridge (deprecated/removed)**: older node transport (see [Bridge protocol](/gateway/bridge-protocol)); no longer advertised for discovery.
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Protocol details:
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- [Gateway protocol](/gateway/protocol)
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- [Bridge protocol (legacy)](/gateway/bridge-protocol)
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## Why we keep both “direct” and SSH
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- **Direct WS** is the best UX on the same network and within a tailnet:
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- auto-discovery on LAN via Bonjour
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- pairing tokens + ACLs owned by the gateway
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- no shell access required; protocol surface can stay tight and auditable
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- **SSH** remains the universal fallback:
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- works anywhere you have SSH access (even across unrelated networks)
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- survives multicast/mDNS issues
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- requires no new inbound ports besides SSH
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## Discovery inputs (how clients learn where the gateway is)
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### 1) Bonjour / mDNS (LAN only)
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Bonjour is best-effort and does not cross networks. It is only used for “same LAN” convenience.
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Target direction:
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- The **gateway** advertises its WS endpoint via Bonjour.
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- Clients browse and show a “pick a gateway” list, then store the chosen endpoint.
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Troubleshooting and beacon details: [Bonjour](/gateway/bonjour).
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#### Service beacon details
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- Service types:
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- `_clawdbot-gw._tcp` (gateway transport beacon)
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- TXT keys (non-secret):
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- `role=gateway`
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- `lanHost=<hostname>.local`
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- `sshPort=22` (or whatever is advertised)
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- `gatewayPort=18789` (Gateway WS + HTTP)
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- `gatewayTls=1` (only when TLS is enabled)
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- `gatewayTlsSha256=<sha256>` (only when TLS is enabled and fingerprint is available)
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- `canvasPort=18793` (default canvas host port; serves `/__clawdbot__/canvas/`)
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- `cliPath=<path>` (optional; absolute path to a runnable `clawdbot` entrypoint or binary)
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- `tailnetDns=<magicdns>` (optional hint; auto-detected when Tailscale is available)
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Disable/override:
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- `CLAWDBOT_DISABLE_BONJOUR=1` disables advertising.
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- `gateway.bind` in `~/.clawdbot/clawdbot.json` controls the Gateway bind mode.
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- `CLAWDBOT_SSH_PORT` overrides the SSH port advertised in TXT (defaults to 22).
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- `CLAWDBOT_TAILNET_DNS` publishes a `tailnetDns` hint (MagicDNS).
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- `CLAWDBOT_CLI_PATH` overrides the advertised CLI path.
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### 2) Tailnet (cross-network)
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For London/Vienna style setups, Bonjour won’t help. The recommended “direct” target is:
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- Tailscale MagicDNS name (preferred) or a stable tailnet IP.
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If the gateway can detect it is running under Tailscale, it publishes `tailnetDns` as an optional hint for clients (including wide-area beacons).
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### 3) Manual / SSH target
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When there is no direct route (or direct is disabled), clients can always connect via SSH by forwarding the loopback gateway port.
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See [Remote access](/gateway/remote).
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## Transport selection (client policy)
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Recommended client behavior:
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1) If a paired direct endpoint is configured and reachable, use it.
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2) Else, if Bonjour finds a gateway on LAN, offer a one-tap “Use this gateway” choice and save it as the direct endpoint.
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3) Else, if a tailnet DNS/IP is configured, try direct.
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4) Else, fall back to SSH.
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## Pairing + auth (direct transport)
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The gateway is the source of truth for node/client admission.
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- Pairing requests are created/approved/rejected in the gateway (see [Gateway pairing](/gateway/pairing)).
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- The gateway enforces:
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- auth (token / keypair)
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- scopes/ACLs (the gateway is not a raw proxy to every method)
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- rate limits
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## Responsibilities by component
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- **Gateway**: advertises discovery beacons, owns pairing decisions, and hosts the WS endpoint.
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- **macOS app**: helps you pick a gateway, shows pairing prompts, and uses SSH only as a fallback.
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- **iOS/Android nodes**: browse Bonjour as a convenience and connect to the paired Gateway WS.
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