Setup this registry in the Cargo configuration file (for example ~/.cargo/config.toml):

[registries.forgejo]
index = "sparse+" # Sparse index
# index = "" # Git

[net]
git-fetch-with-cli = true

To install the package using Cargo, run the following command:

cargo add wireless_bridge@0.4.0-rc.0 --registry forgejo

For more information on the Cargo registry, see the documentation.

LoRa–gRPC bridge for Linux (e.g. Raspberry Pi): receives LoRa frames, validates Sigil messages, forwards to gRPC backend. Optional ATECC608A.

wireless_bridge

Embedded LoRa–gRPC bridge for Linux (e.g. Raspberry Pi): receives LoRa frames from sensors, derives and caches keys, validates install/status messages (Sigil protocol), and forwards data to a gRPC backend. Optional ATECC608A secure element for device keys and CA verification.

Features

LoRa (SX1278) over SPI: receiver with DIO0 interrupt, messaging via Sigil (models, encryption, init, keys).
gRPC client to a local install/bridge service (e.g. localhost:50051).
SQLite (via db_handler) for keys and sensor data; key cache with expiration and periodic cleanup.
ATECC608A (optional): device keypair (slot 0), CA public key (slot 8), signature (slot 9), hardware RNG; host-side ECDSA verification when ATECC_CA_PUBKEY_PATH is set.
Master secret: loaded from ATECC608A (slot, see LORA_MASTER_SECRET_ATECC_SLOT), or LORA_MASTER_SECRET (base64), or /etc/bridge/master.key / ./master.key; used to derive install/validation keys.

Prerequisites

Rust (stable), and for cross-compilation: cross or rustup target add armv7-unknown-linux-musleabihf.
Linux (the binary is built for Linux only; SPI, I2C, GPIO via linux-embedded-hal and gpio-cdev).
Hardware: LoRa module (SX1278) on SPI, optional ATECC608A on I2C. Protobufs are compiled at build time (proto/).

Hardware (Raspberry Pi / SX1278)

Raspberry Pi Pin	LoRa Module Pin
GPIO10 (MOSI)	MOSI
GPIO9 (MISO)	MISO
GPIO11 (SCK)	SCK
GPIO8 (CE0)	NSS
GPIO27	RESET
GPIO17	DIO0
GND	GND
3.3V	VCC

SPI device is /dev/spidev0.0 by default. I2C for ATECC608A: /dev/i2c-1, address 0x60.

Build

# Native (Linux)
cargo build --release

# Cross-compile for Raspberry Pi (armv7)
rustup target add armv7-unknown-linux-musleabihf
cross build --release --target=armv7-unknown-linux-musleabihf

Binary: target/<target>/release/wireless_bridge.

Run

The bridge expects a master secret and (optionally) a config path. Example:

# Preferred: master secret from ATECC608A (slot 10, 32 bytes provisioned)
export LORA_MASTER_SECRET_ATECC_SLOT=10

# Or: master secret from env or file
# export LORA_MASTER_SECRET="<base64-32-bytes>"

export RUST_LOG=debug   # optional: debug, info, warn, error

# Optional overrides (defaults shown)
# CONFIG_FILE=/path/to/config.json
# LORA_ATECC_I2C_PATH=/dev/i2c-1
# LORA_DIO_CHIP=/dev/gpiochip0
# LORA_DIO_LINE=13
# ATECC_CA_PUBKEY_PATH=/path/to/ca_public_key.bin

./wireless_bridge

Master secret: prefer ATECC608A (LORA_MASTER_SECRET_ATECC_SLOT, e.g. 10) with 32 bytes provisioned in that slot; otherwise set LORA_MASTER_SECRET (base64) or use /etc/bridge/master.key (see Security / Master secret).
ATECC608A: optional; if not present, the bridge runs without the secure element. If present, device pubkey (slot 0), CA pubkey (slot 8 or file), and signature (slot 9) are used for validation and RNG.

Environment variables

Variable	Description	Default
`LORA_MASTER_SECRET_ATECC_SLOT`	ATECC608A slot number (32 bytes). If set, master secret is read from this slot first (recommended).	—
`LORA_MASTER_SECRET`	Master secret, base64 (32 bytes).	— (or `/etc/bridge/master.key`, then `./master.key`)
`CONFIG_FILE`	Path to application/config JSON (e.g. DB path).	—
`RUST_LOG`	Log level: `error`, `warn`, `info`, `debug`, `trace`.	—
`LORA_ATECC_I2C_PATH`	I2C device for ATECC608A.	`/dev/i2c-1`
`LORA_DIO_CHIP`	GPIO chip for LoRa DIO0.	`/dev/gpiochip0`
`LORA_DIO_LINE`	GPIO line for LoRa DIO0.	`13`
`ATECC_CA_PUBKEY_PATH`	Optional path to CA public key file (64 or 65 bytes).	— (else CA from ATECC slot 8)

Project structure

bridge/
├── proto/              # Protobuf definitions (status, install, bridge)
├── src/
│   ├── main.rs         # Entry point (Linux only)
│   ├── app (inline)    # SPI/GPIO/LoRa init, gRPC client, LoRa handler loop
│   ├── cache/          # Key cache (LRU, expiration)
│   ├── errors/         # Error types
│   ├── grpc/           # gRPC generated stubs and common protos
│   ├── handler/        # gRPC and LoRa handlers
│   ├── model_adapter/  # Sensor type and status mapping
│   ├── proxy/          # Proxy utilities
│   ├── radio/          # Radio (LoRa) abstraction
│   ├── random/         # Hardware RNG (ATECC608A)
│   ├── security/       # Master secret, ATECC608A integration
│   └── warpper/        # GPIO and DIO interrupt
├── tests/              # Integration and unit tests
├── scripts/            # tests.sh, build.sh, deploy.sh, runbridge.sh
├── build.rs            # Compiles proto files (tonic-prost-build)
├── Cargo.toml
└── LICENSE

Tests

./scripts/tests.sh
# or
CONFIG_FILE=/path/to/config_test.json cargo test -- --test-threads=1 --nocapture

Tests use a config path for the database layer when required; see scripts/tests.sh and test code for details.

Dependencies (registries)

The crate depends on private Forgejo packages: tools, lora, db_handler, sigil, atecc608x. Configure the Forgejo registry in .cargo/config.toml and authenticate (e.g. cargo login --registry forgejo) before building.

License

Personal Use Only — Non-Commercial. See LICENSE for full terms and disclaimers.

ID	Version
P256	^0.13
anyhow	^1.0.102
atecc608x	=0.2.0-rc.4
base64	^0.22
chacha20poly1305	^0.10.1
chrono	^0.4.38
db_handler	=0.1
embedded-hal	^1.0.0
env_logger	^0.11
getrandom	^0.4.2
hex	^0.4
hkdf	^0.12
log	^0.4.27
lora	=0.3.0-rc.0
lru	^0.16.3
prost	^0.14.3
sha2	^0.10
sigil	=0.4.0-rc.0
sqlx	^0.8.6
tokio	^1.50.0
tonic	^0.14.5
tonic-prost	^0.14.5
tools	=0.3.0-rc.0
async-std	^1.13.1
futures-util	^0.3.17
indoc	^2.0.6
tempfile	^3.27.0
tokio	^1.7
tonic-prost-build	^0.14.5
gpio-cdev	^0.6.0
linux-embedded-hal	^0.4.0

wireless_bridge (0.4.0-rc.0)

Installation

About this package