Systemd service units for the AXIA - ALSA soundcard driver for Livewire

systemd service units and udev rules for managing the AXIA - ALSA soundcard driver for Livewire services.

Motivation

Paravel Systems offers an AXIA - ALSA
Soundcard Driver for
Livewire (also
known as Axia IP Audio Driver for Linux) which consists out of a Linux kernel
module (snd-axia) and three related daemons (axialwrd, axiaadvd and
axiagpr).

The axia-alsa CentOS
RPM provides a
SysV-style init script (axiad) and an auto-generated systemd service unit
wrapper (axiad.service). Apart from being only a wrapper around the
SysV-style init script, everything is bundled into one script (module loading,
device node creation and the start of the three daemons). Furthermore
the daemons will all be started with root privileges and the startup options
are hard coded into the init script.

These were the reasons and main motivations for re-creating the start-up of the
services in a more modern and flexible fashion.

Features

Dedicated systemd services (no SysV wrapper) with configurable startup
options.
One systemd service unit per service
- axialwrd.service - Axia Livewire Routing
  Daemon
- axiaadvd.service - Axia Advertising Daemon
- axiagpr.service - Axia GPIO Bridge for
  Livewire/Control Surface control
snd-axia Kernel module loading via standard systemd
modules-load.d
mechanism.
Automatic /dev/axia0 device node creation via
udev upon
module loading
Minimization of root privileges
firewalld service file (for IGMP and Livewire
Routing Protocol)

Installation

A valid serial number (license) for the Axia IP-Audio Driver for Linux from
Paravel Systems is required.

RPM installation on CentOS

The systemd service units and udev rules are packaged for CentOS 7 and are
available on Radio RaBe's Audio Packages for Enterprise Linux
repository. They
can be installed as follows:

# Install the RaBe APEL repository configuration
curl -o /etc/yum.repos.d/home:radiorabe:audio.repo \
     http://download.opensuse.org/repositories/home:/radiorabe:/audio/CentOS_7/home:radiorabe:audio.repo


# Import the Paravel-Broadcast GPG key
rpm --import \
    http://download.paravelsystems.com/CentOS/7com/RPM-GPG-KEY-Paravel-Broadcast

# Install the Paravel-Commercial repository configuration
curl -o /etc/yum.repos.d/Paravel-Commercial.repo \
    http://download.paravelsystems.com/CentOS/7com/Paravel-Commercial.repo


# Install the required packages (axia-alsa-cli contains the lwlicense command)
yum install systemd-axia-alsa axia-alsa-cli

# Reload the systemd manager configuration
systemctl daemon-reload

# Register your license
lwlicense <SERIAL-NUMBER>

Afterwards, reboot your system or manually load the kernel module (modprobe snd-axia), then follow the Usage section.

Manual installation on CentOS

To install the files manually, use the provided Makefile and set
the prefix to / (which will install the files directly into the root of your
system):

# Install all files
make prefix=/ install

# Create the axia service user and group
userName='axia'

useradd --comment "${userName} system user account" \
        --home-dir /dev/null \
        --no-create-home \
        --system \
        --shell /sbin/nologin \
        --user-group \
        "${userName}"


# Import the Paravel-Broadcast GPG key
rpm --import \
    http://download.paravelsystems.com/CentOS/7com/RPM-GPG-KEY-Paravel-Broadcast

# Install the Paravel-Commercial repository configuration
curl -o /etc/yum.repos.d/Paravel-Commercial.repo \
    http://download.paravelsystems.com/CentOS/7com/Paravel-Commercial.repo

# Install the required axia-alsa packages
yum install axia-alsa axia-alsa-cli

# Reload the systemd manager configuration
systemctl daemon-reload

# Register your license
lwlicense <SERIAL-NUMBER>

Afterwards, reboot your system or manually load the kernel module (modprobe snd-axia), then follow the Usage section.

Usage

Kernel module and device node

The axia-alsa kernel module and its related /dev/axia0 device node should
be automatically loaded and created upon boot. You can check that with the
following commands.

Check that the module was loaded:

lsmod | grep snd_axia

snd_axia               24539  2 
snd_pcm               106416  2 snd_axia
snd                    83432  8 snd_timer,snd_pcm,snd_seq,snd_seq_device,snd_axia

Check that the device node was created by udev

ls -la /dev/axia0

crw-r--r--. 1 root root 247, 0 Sep 11 22:09 /dev/axia0

Kernel module parameters

The axia-alsa kernel module parameters (such as the number of virtual
livewire devices) can be changed within /etc/modprobe.d/snd-axia.conf

Firewall

In case you have a local firewall active, make sure that you allow at least the
IGMP protocol. This is required for IGMP
snooping to work and allows the axialwrd daemon to maintain multicast
subscriptions of the audio and sync streams.
For remote control of the audio routes via the Livewire Routing Protocol, the
TCP port 93 needs to be allowed as well.

If you use firewalld, the required rules can be
added via the included firewalld service file:

# Replace YOUR-ZONE with your actual zone name or omit --zone= to use the
# default zone
firewall-cmd --permanent --zone=YOUR-ZONE --add-service=axialwrd
firewall-cmd --reload

This will add the following iptables/netfiler rules:

-A IN_YOUR-ZONE_allow -p tcp -m tcp --dport 93 -m conntrack --ctstate NEW -j ACCEPT
-A IN_YOUR-ZONE_allow -p igmp -m conntrack --ctstate NEW -j ACCEPT

Consider restricting access to the Livewire Routing port (tcp/93) to a
specific management IP address or range.

systemd services

The three Axia daemons can be managed with the following commands.

Axia Livewire Routing Daemon (`axialwrd`)

# Start the axialwrd service
systemctl start axialwrd.service

# Stop the axialwrd service
systemctl stop axialwrd.service

# Restart the axialwrd service
systemctl restart axialwrd.service

# Get the status of the axialwrd service
systemctl status axialwrd.service

# Show log messages of the axialwrd service
journalctl -u axialwrd.service

# Tail the log messages of the axialwrd service
journalctl -u axialwrd.service -f

Axia Advertising Daemon (`axiaadvd`)

# Start the axiaadvd service
systemctl start axiaadvd.service

# Stop the axiaadvd service
systemctl stop axiaadvd.service

# Restart the axiaadvd service
systemctl restart axiaadvd.service

# Get the status of the axiaadvd service
systemctl status axiaadvd.service

# Show log messages of the axiaadvd service
journalctl -u axiaadvd.service

# Tail the log messages of the axiaadvd service
journalctl -u axiaadvd.service -f

Axia GPIO Bridge for Livewire/Control Surface control (`axiagpr`)

# Start the axiagpr service
systemctl start axiagpr.service

# Stop the axiagpr service
systemctl stop axiagpr.service

# Restart the axiagpr service
systemctl restart axiagpr.service

# Get the status of the axiagpr service
systemctl status axiagpr.service

# Show log messages of the axiagpr service
journalctl -u axiagpr.service

# Tail the log messages of the axiagpr service
journalctl -u axiagpr.service -f

Axia daemons startup options

The startup options for all three Axia daemons can be changed within the
systemd environment
file
located at /etc/axia/systemd-env.conf. Refer to the daemon's respective
--help output for a list of supported startup options and remember to restart
the respective system service unit after making a change to this file.

The following example startup configuration, instructs axialwrd and axiaadvdto use the eth1 network interface rather than the default of eth0:

# Systemd environment file for the Axia services

# Axia Livewire Routing Daemon (axialwrd) startup options, see
# 'axialwrd --help' for supported options.
AXIALWRD_OPTS="-i eth1"

# Axia Advertising Daemon (axiaadvd) startup options, see 'axiaadvd --help' for
# supported options.
AXIAADVD_OPTS="-if eth1"

Monitoring

Zabbix users can import the
Zabbix Axia ALSA Soundcard Driver for Livewire
monitoring templates
in order to monitor the various components of the Axia IP Audio
Driver for Linux.

Troubleshooting

The following commands might help on debugging.

Systemd service units status

Systemd service units status:

systemctl status axialwrd.service
systemctl status axiaadvd.service
systemctl status axiagpr.service
systemctl status sys-module-snd_axia.device

snd_axia kernel module

Check that the kernel module has been loaded and the device node was
created.

udev status

udev sysfs info:

udevadm info /sys/module/snd_axia

P: /module/snd_axia
E: DEVNAME=/dev/axia0
E: DEVPATH=/module/snd_axia
E: MAJOR=247
E: MINOR=0
E: NAME=axia0
E: SUBSYSTEM=module
E: TAGS=:systemd:
E: USEC_INITIALIZED=18014

udev add event test:

udevadm test -a add /sys/module/snd_axia

[...]
Reading rules file: /usr/lib/udev/rules.d/90-snd-axia.rules
[...]
IMPORT 'snd-axia.sh --env' /usr/lib/udev/rules.d/90-snd-axia.rules:11
starting 'snd-axia.sh --env'
'snd-axia.sh --env'(out) 'NAME=axia0'
'snd-axia.sh --env'(out) 'MAJOR=247'
'snd-axia.sh --env'(out) 'MINOR=0'
'snd-axia.sh --env'(out) 'DEVNAME=/dev/axia0'
'snd-axia.sh --env' [2793] exit with return code 0
RUN 'snd-axia.sh --mknod' /usr/lib/udev/rules.d/90-snd-axia.rules:11
created db file '/run/udev/data/+module:snd_axia' for '/module/snd_axia'
ACTION=add
DEVNAME=/dev/axia0
DEVPATH=/module/snd_axia
MAJOR=247
MINOR=0
NAME=axia0
SUBSYSTEM=module
TAGS=:systemd:
USEC_INITIALIZED=18014
run: 'snd-axia.sh --mknod'
Unload module index
Unloaded link configuration context.

udev helper script tests:

# Create udev env vars
/usr/lib/udev/snd-axia.sh --env

# Create the /dev/axia0 device node
/usr/lib/udev/snd-axia.sh --mknod

# Remove the /dev/axia0 device node
/usr/lib/udev/snd-axia.sh --rmnod

Network status

Network status and debugging:

# List socket binding
ss -apn | grep -i axia

# List socket bindings on legacy systems
netstat -anp | grep axia

# Firewall (if active)
firewall-cmd --zone <ZONE> --list-all
iptables -nvL

# Display multicast group membership information for IPv4
ip -4 maddr

# Display multicast group membership information for IPv4 on legacy systems
netstat -gn4

# Package dump
tcpdump -i <DEVICE> -nn -vvv 'net 239.0.0.0/8'

License

systemd-axia-alsa is free software: you can redistribute it and/or modify it under
the terms of the GNU Affero General Public License as published by the Free
Software Foundation, version 3 of the License.

radiorabe/systemd-axia-alsa

Systemd service units for the AXIA - ALSA soundcard driver for Livewire

Motivation

Features

Installation

RPM installation on CentOS

Manual installation on CentOS

Usage

Kernel module and device node

Kernel module parameters

Firewall

systemd services

Axia Livewire Routing Daemon (`axialwrd`)

Axia Advertising Daemon (`axiaadvd`)

Axia GPIO Bridge for Livewire/Control Surface control (`axiagpr`)

Axia daemons startup options

Monitoring

Troubleshooting

Systemd service units status

snd_axia kernel module

udev status

Network status

License

Copyright

On this page

Languages

Contributors

Latest Release

radiorabe/systemd-axia-alsa

Systemd service units for the AXIA - ALSA soundcard driver for Livewire

Motivation

Features

Installation

RPM installation on CentOS

Manual installation on CentOS

Usage

Kernel module and device node

Kernel module parameters

Firewall

systemd services

Axia Livewire Routing Daemon (axialwrd)

Axia Advertising Daemon (axiaadvd)

Axia GPIO Bridge for Livewire/Control Surface control (axiagpr)

Axia daemons startup options

Monitoring

Troubleshooting

Systemd service units status

snd_axia kernel module

udev status

Network status

License

Copyright

On this page

Languages

Contributors

Latest Release

Axia Livewire Routing Daemon (`axialwrd`)

Axia Advertising Daemon (`axiaadvd`)

Axia GPIO Bridge for Livewire/Control Surface control (`axiagpr`)