Data for Freifunk Map, Graph and Node List

ffmap-backend gathers information on the batman network by invoking :

• batctl (might require root),
• alfred-json and
• batadv-vis

The output will be written to a directory (-d output).

Copy mkmap.sh-example to mkmap.sh and adapt to your needs, test backend.py for example with:

backend.py -d /path/to/output -a /path/to/aliases.json --vpn ae:7f:58:7d:6c:2a d2:d0:93:63:f7:da

Run backend.py --help for a quick overview of all available options.

For the script's regular execution add the following file to cron in /etc/cron.d/ffmap-backend:

[email protected]
# Freifunk Map Updates
PATH=/usr/sbin:/usr/bin:/sbin:/bin
* * * * *       root nice -n 19 /path/to/mkmap.sh > /dev/null 2>&1
# EOF

Dependencies

• Python 3
• Python 3 Package Networkx
• alfred-json
• rrdtool (if run with --with-rrd)

Install

on debian jessie:

apt-get install python3-networkx cmake libjansson-dev zlib1g-dev

on debian wheezy:

apt-get install cmake libjansson-dev zlib1g-dev
pip-3.2 install networkx

Running as unprivileged user

Some information collected by ffmap-backend requires access to specific system resources.

Make sure the user you are running this under is part of the group that owns the alfred socket, so alfred-json can access the alfred daemon.

# ls -al /var/run/alfred.sock
srw-rw---- 1 root alfred 0 Mar 19 22:00 /var/run/alfred.sock=
# adduser map alfred
Adding user `map' to group `alfred' ...
Adding user map to group alfred
Done.
$ groups
map alfred

Running batctl requires passwordless sudo access, because it needs to access the debugfs to retrive the gateway list.

# echo 'map ALL = NOPASSWD: /usr/sbin/batctl' | tee /etc/sudoers.d/map
map ALL = NOPASSWD: /usr/sbin/batctl
# chmod 0440 /etc/sudoers.d/map

That should be everything. The script automatically detects if it is run in unprivileged mode and will prefix sudo where necessary.

Data format

nodes.json

{ 'nodes': {
    node_id: { 'flags': { flags },
               'firstseen': isoformat,
               'lastseen': isoformat,
               'nodeinfo': {...},         # copied from alfred type 158
               'statistics': {
                  'uptime': double,       # seconds
                  'memory_usage': double, # 0..1
                  'clients': double,
                  'rootfs_usage': double, # 0..1
                  'loadavg': double,
                  'gateway': mac
                }
             },
    ...
  }
  'timestamp': isoformat
}

flags (bool)

• online
• gateway

Old data format

If you want to still use the old ffmap-d3 front end, you can use the file ffmap-d3.jq to convert the new output to the old one:

jq -n -f ffmap-d3.jq \
    --argfile nodes nodedb/nodes.json \
    --argfile graph nodedb/graph.json \
    > nodedb/ffmap-d3.json

Then point your ffmap-d3 instance to the ffmap-d3.json file.

Removing owner information

If you'd like to redact information about the node owner from nodes.json, you may use a filter like jq. In this case, specify an output directory different from your webserver directory, e.g.:

./backend.py -d /ffmap-data

Don't write to files generated in there. ffmap-backend uses them as its database.

After running ffmap-backend, copy graph.json to your webserver. Then, filter nodes.json using jq like this:

 jq '.nodes = (.nodes | with_entries(del(.value.nodeinfo.owner)))' \
   < /ffmap-data/nodes.json > /var/www/data/nodes.json

This will remove owner information from nodes.json before copying the data to your webserver.