Moblink (Rust🦀 edition)

Use spare devices as extra SRTLA bonding connections. The same functionality is part of Moblin on iOS.

Originally inspired by the Moblink Kotlin/Android code.

Features

• WebSocket Connection: Connects to Moblin via WebSocket (e.g., wss://...)
• Auth Handling: Implements the same challenge–response authentication logic as the Android client
• UDP Relay: Forwards UDP packets between the remote streamer and a local destination.
• mDNS: Automatically connect to nearby Moblink devices.

Requirements

• Rust (stable, e.g., 1.85+)
• Cargo (for building)

Usage

Use on Belabox

ssh user@belabox.local

password: See belabox under advanced / developer

ssh to your belabox and run this:

wget -q -O - https://raw.githubusercontent.com/datagutt/moblink-rust/refs/heads/main/install/belabox/install.sh | sudo sh

Then start a Moblink relay and open http://belabox.local/ in your browser.

If not, make sure your relay has a short name. At most ~10 characters --> Make sure the password is "1234" and put it on AUTO on the android phone.

Build

# 1. Clone this repository (or copy the code)
git clone https://github.com/datagutt/moblink-rust.git
cd moblink-rust
# Set nightly (optional)
rustup override set nightly
# 2. Build the project
cargo build --release

Run Relay

./target/release/moblink-relay \
--name "RelayName" \
--id "UUID" \
--streamer-url ws://192.168.1.2:7777 \
--password "secret123" \
--bind-address 192.168.1.10
--log-level debug

Command-Line Arguments

Argument	Description	Default	Example
--name	Name to identify the relay	Hostname	--name CameraRelay1
--id	UUID to identify the Relay	Generated	--id UUID
--streamer-url	WebSocket URL to connect to the streamer	None (multicast DNS)	--streamer-url wss://example.com/ws
--password	Password used in the challenge–response authentication	1234	--password mySecret
--log-level	Logging verbosity (e.g., error, warn, info, debug, trace)	info	--log-level debug
--bind-address	Local modem IP address to bind for UDP socket	0.0.0.0	--bind-address 192.168.1.10
--status-executable	Status executable. Print status to standard output on format {"batteryPercentage": 93}	None	--status-executable ./status.sh
--status-file	Status file. Contains status on format {"batteryPercentage": 93}	None	--status-file status.json

Relay status (today only battery percentage) is sent to the streamer if --status-executable or --status-file is given and outputting a valid JSON object as seen above.

Run Relay Service

moblink-relay connects a single network interface. moblink-relay-service is a supervisor that watches every eligible network interface and starts one relay per interface automatically. It is useful on machines with several uplinks (for example a router with Ethernet, Wi-Fi, and cellular), where each uplink becomes an independent bonding path.

./target/release/moblink-relay-service \
--password "secret123" \
--interface-name-override eth0=WAN \
--interface-name-override wwan0=LTE \
--runtime-status-file /tmp/moblink-relay-status.json

By default the service discovers streamers over multicast DNS. Pass one or more --streamer-url to connect to fixed streamers instead, which is helpful where multicast DNS is unreliable (for example across router uplinks behind NAT).

Command-Line Arguments

Argument	Description	Default	Example
--password	Password used in the challenge response authentication	1234	--password mySecret
--network-interfaces-to-allow	Regex of interface names to allow (^/$ anchors added automatically). Repeatable. Localhost is never allowed.	All	--network-interfaces-to-allow 'eth.*'
--network-interfaces-to-ignore	Regex of interface names to ignore (^/$ anchors added automatically). Repeatable.	None	--network-interfaces-to-ignore 'docker.*'
--streamer-url	Connect to this streamer URL directly instead of discovering over multicast DNS. Repeatable.	None (multicast DNS)	--streamer-url ws://192.168.1.2:7777
--interface-name-override	Rename the relay shown in the Moblin app for a given interface, as interface=label. Repeatable.	None	--interface-name-override eth0=WAN
--runtime-status-file	Write relay and streamer state as JSON to this file, for external UIs to display connection status and streamer IPs.	None	--runtime-status-file status.json
--status-executable	Status executable. Print status to standard output on format {"batteryPercentage": 93}	None	--status-executable ./status.sh
--status-file	Status file. Contains status on format {"batteryPercentage": 93}	None	--status-file status.json
--database	File storing the per-interface relay identities	moblink-relay-service.json	--database /etc/moblink/relays.json
--log-level	Logging verbosity (e.g., error, warn, info, debug, trace)	info	--log-level debug

The runtime status file is rewritten whenever relays or streamers change. It contains a JSON object with connected, manual_streamer, a streamers array, and a relays array (each relay reporting its interface name, interface address, and the streamer name, URL, and host it serves).

Run Streamer

./target/release/moblink-streamer \
--websocket-server-address 192.168.1.2 \
--destination-address 172.120.50.214 \
--destination-port 5000

Command-Line Arguments

Argument	Description	Default	Example
--name	Name to identify the streamer	Hostname	--name CameraRelay1
--id	Id to identify the streamer using multicast DNS	Hostname	--id UUID
--password	Password used in the challenge–response authentication	1234	--password mySecret
--log-level	Logging verbosity (e.g., error, warn, info, debug, trace)	info	--log-level debug
--websocket-server-address	Local IP address to bind websocket server to		--websocket-server-address 192.168.1.10
--websocket-server-port	Local port to bind the websocket server to	7777	--websocket-server-port 7778
--tun-ip-network	TUN IP network (CIDR notation). TUN network interfaces will be assigned IP addresses from this network.	10.3.3.0/24	--tun-ip-network 10.1.1.0/24
--destination-address	Streaming destination address		--status-file status.json
--destination-port	Streaming destination port		--status-file status.json

Relay Architecture

1. WebSocket Connection

   • Establishes a WebSocket to streamer_url, or if not provided, tries to find nearby Moblink streamers through multicast DNS.
   • Handles “Hello” messages, calculates authentication, and sends an “Identify” message.

2. Handling Requests

   • When a startTunnel request is received, the relay spawns two async tasks:
     • (relay_to_destination): Forwards traffic from streamer → destination
     • (relay_to_streamer): Forwards traffic from destination → streamer

3. UDP Binding

   • By default, it binds a UDP socket to whatever we deem to be the main network interface.

FAQ

Q: How do I integrate this into my own application?
A: Use the moblink-rust crate

---

License: This project is distributed under the terms of the MIT license.

Enjoy using Moblink!