Daemon

Linux Daemon (infrafid)

infrafid is the server-side component of InfraFi. It listens for IR transmissions from the Flipper Zero, decodes the WiFi credentials, and uses them to connect the Linux machine to a WiFi network.

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Building

Requires GCC and Linux kernel headers (linux/lirc.h).

cd daemon
make

To install and enable as a systemd service:

sudo ./install.sh

The installer:

1. Detects LIRC or evdev hardware
2. Configures the IR receiver for RC-6 and NEC protocols
3. Creates a udev rule (/etc/udev/rules.d/99-infrafid-ir.rules) to persist protocol config across reboots
4. Builds and installs the binary
5. Enables and starts the infrafid.service

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CLI Reference

Usage: infrafid [options]

Options:
  -d, --device PATH       LIRC device for RX (default: /dev/lirc0)
  -e, --evdev PATH        Use evdev input device for RX (NEC via MSC_RAW)
  -s, --serial PATH       Serial device for Arduino IR transceiver
  -a, --ack-device PATH   LIRC device for ACK TX (default: same as --device)
  -f, --foreground        Run in foreground (don't daemonize)
  -v, --verbose           Verbose/debug logging
  -V, --version           Show version and exit
  -h, --help              Show help

Mutually exclusive: --evdev and --serial cannot be used together.

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Usage Examples

# LIRC receiver, foreground with verbose logging (most common for testing)
sudo infrafid -f -v

# Different RX device
sudo infrafid -d /dev/lirc1 -f -v

# Separate TX device for ACK (RX on lirc0, ACK on lirc1)
sudo infrafid -d /dev/lirc0 -a /dev/lirc1

# Arduino serial backend (handles both RX and TX ACK)
sudo infrafid -s /dev/ttyACM0 -f -v

# Arduino RX with separate LIRC device for ACK TX
sudo infrafid -s /dev/ttyACM0 -a /dev/lirc1

# evdev input (e.g. Squeezebox Touch)
sudo infrafid -e /dev/input/event1 -f -v

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Receiver Backends

LIRC (-d /dev/lirc0)

The default backend. Opens the LIRC device in LIRC_MODE_SCANCODE mode, which uses kernel-level RC-6/NEC decoding. This avoids the hardware FIFO overflow problems that occur with raw mode on small CIR chips like the ITE8708.

Requires /dev/lirc0 (or specified device) and the corresponding kernel RC decoder enabled.

evdev (-e /dev/input/eventN)

For devices that expose IR via the Linux input subsystem using MSC_RAW events. NEC protocol only, using FAB4-style bit ordering (as found on Squeezebox Touch and similar embedded Linux devices).

Serial / Arduino (-s /dev/ttyACMx)

For use with an Arduino Pro Micro running the InfraFi firmware. The daemon opens the serial device, performs a handshake with the Arduino, and reads decoded RC-6 scancodes from it. The same connection is used to command the Arduino's IR LED for ACK transmission.

See Arduino Firmware for setup details.

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ACK Transmission

After a connection attempt (success or failure), the daemon can send an IR response back to the Flipper. The response uses the same frame format as the incoming transmission.

• Success payload: OK:192.168.1.102 (includes the assigned IP)
• Failure payload: FAIL

The Flipper waits up to 30 seconds for an ACK before timing out. ACK must be enabled in the Flipper app settings.

ACK with LIRC TX:

sudo infrafid -d /dev/lirc0 -a /dev/lirc1

ACK with Arduino serial (both RX and TX on same connection):

sudo infrafid -s /dev/ttyACM0

If the TX device cannot be opened, ACK is silently disabled and the daemon continues operating in RX-only mode.

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Network Management

infrafid supports two network management systems and automatically detects which one is active:

NetworkManager (preferred)

If nmcli is available and NetworkManager is running, the daemon uses it:

nmcli device wifi connect "<SSID>" password "<password>"

For hidden networks:

nmcli device wifi connect "<SSID>" password "<password>" hidden yes

ifupdown (fallback)

If NetworkManager is not detected, the daemon falls back to writing /etc/network/interfaces and running ifdown/ifup.

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Rollback on Failure

Before attempting to connect to a new network, the daemon saves the currently active SSID. If the connection attempt fails:

1. The daemon sends a FAIL ACK to the Flipper.
2. It attempts to reconnect to the previous network using the saved SSID.
3. If rollback also fails, a warning is logged and manual intervention may be needed.

This prevents the machine from being left disconnected if bad credentials are sent.

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Systemd Service

The systemd unit file is installed at /etc/systemd/system/infrafid.service.

systemctl status infrafid      # Check service status
systemctl restart infrafid     # Restart
journalctl -u infrafid -f      # Follow logs

Service configuration: To pass custom arguments to the daemon, create /etc/default/infrafid:

# /etc/default/infrafid
INFRAFID_ARGS="--serial /dev/ttyACM0 --verbose"

Then restart the service.

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Logging

infrafid logs to syslog (facility LOG_DAEMON). When run with -f (foreground), logs also print to stderr.

With -v (verbose), debug-level messages are included, including raw scancode values.

# View recent logs
journalctl -u infrafid --since "1 hour ago"

# Follow live
journalctl -u infrafid -f

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Source Layout

daemon/
  main.c          # Entry point: CLI parsing, main loop, credential handling
  wfr_lirc.h/c    # LIRC scancode reader (/dev/lirc0, LIRC_MODE_SCANCODE)
  wfr_evdev.h/c   # evdev input reader (/dev/input/eventN, NEC via MSC_RAW)
  wfr_serial.h/c  # Serial backend for Arduino transceiver
  wfr_decode.h/c  # IR scancode reassembler (START/DATA/END -> payload + CRC check)
  wfr_network.h/c # WiFi connector (NetworkManager/ifupdown) with rollback
  wfr_ack.h/c     # LIRC TX ACK sender
  Makefile
  infrafid.service
  install.sh