Table of Contents
Custom Applications in LinBPQ
When you connect to a BPQ32 Node, you may be offered custom applications as well as the standard commands:
ABNGDN:G6FJI} BBS CHAT HARS CONNECT BYE INFO NODES PORTS ROUTES USERS MHEARD
Here the first three commands are applications defined in the nodes configuration file, bpq32.cfg:
APPLICATION 1,BBS,,G6FJI-2,ABIBBS,254 APPLICATION 2,CHAT,,G6FJI-1,ABICHT,254 APPLICATION 3,HARS,C 1 HARS S
Applications 1 and 2, BBS and CHAT are standard features in BPQ32; Application 3 is simply a user shortcut: typing
HARS is the same as typing
C 1 HARS S.
BPQ32 also has a facility to make a TCP connection to a port on the same machine, which allows you to create custom applications within your node. This page describes setting up an application on a Linux system using systemd - I have not seen any documentation to make this work on Windows.
'Hello World' Example Application
This example assumes you have a 'standard' BPQ32 installation running on Linux, with Port 1 using RF and Port 2 using Telnet.
First we must add a CMDPORT line to the Telnet Port. The syntax is
CMDPORT <TCP port 0> <TCP port 1> … <TCP port n>, eg:
CMDPORT 63001 63002
Then we add a Node APPLICATION which calls that port. The options used here are:
- Application number
- Application name
- Command to execute
- User to connect as
APPLICATION 5,HELLO-WORLD,C 2 HOST 0 S,G6FJI
The command syntax is
C(onnect) <port> HOST <zero-based command port number> S; the S at the end means return to the current session rather than disconnect completely.
Custom Application Configuration
Our 'Hello World' application is simply a bash script called as a systemd service. Using your editor of choice, create a file 'hello-world.sh' containing this script:
#!/bin/bash echo "Hello world"
Make the script executable and check you can run it:
martinr@UbuMini:~$ chmod +x hello-world.sh martinr@UbuMini:~$ ./hello-world.sh Hello world
Now we need to set up the systemd service to call the script. This is in two parts - the socket and the service. First create the socket part with
sudo nano /lib/systemd/system/hw.socket
[Unit] Description=Hello World [Socket] ListenStream=63001 Accept=yes [Install] WantedBy=sockets.target
The bit that matters here is the port number in the ListenStream must match the CMDPORT you created in the BPQ configuration.
Then we need the matching service file:
sudo nano /lib/systemd/system/hw@.service - note the @ in the name.
[Unit] Description=Hello World Server [Service] ExecStart=/home/martinr/hello-world.sh StandardInput=socket
Here the important parts are the script to run and the line telling it to take standard input from the socket - there won't be a keyboard connected to the service.
Reload the systemd configuration and start the service, then test it using netcat:
martinr@UbuMini:~$ sudo systemctl daemon-reload martinr@UbuMini:~$ sudo systemctl start hw.socket martinr@UbuMini:~$ nc localhost 63001 Hello world
To have the new service run on start up, run this command:
martinr@UbuMini:~$ sudo systemctl enable hw.socket
Finally restart your node and test:
ABNGDN:G6FJI} BBS CHAT HARS HELLO-WORLD CONNECT BYE INFO NODES PORTS ROUTES USERS MHEARD HELLO-WORLD Connected to HELLO-WORLD Hello world Returned to Node ABNGDN:G6FJI
I found these links useful in getting this to work:
The official documentation uses inetd and doesn't really explain the significance of the port list in the CMDPORT line:
This presentation is quite helpful once you work out the typos and which bits are meant to be there:
These pages were useful for understanding the systemd services and testing them