Gluon Status Scripts for Servers

These scripts are replacements for the respondd and gluon-alfred packages in Gluon that can be used on servers (like gateways) to broadcast the information needed for example to display the name of the server on node-maps.

Dependencies

• lsb_release
• ethtool
• python3 (>= 3.3)
• If using alfred: alfred binary in PATH

Setup

git clone https://github.com/ffnord/mesh-announce /opt/mesh-announce
cp /opt/mesh-announce/respondd.service /etc/systemd/system/
# adapt the line ExecStart in /etc/systemd/system/respondd.service (see "commandline options")
systemctl daemon-reload
systemctl start respondd
systemctl status respondd

Upgrade

cp /opt/mesh-announce/respondd.service /etc/systemd/system/
git pull
# check /etc/systemd/system/respondd.service for new options/adaptions
systemctl daemon-reload
systemctl restart respondd
systemctl status respondd

Alfred

Open the Alfred port UDP 16962 in your firewall. Add announce.sh to your cronjobs, and let it run every minute, e.g.

PATH=/opt/alfred/:/bin:/usr/bin:/sbin:$PATH /opt/mesh-announce/announce.sh

Respondd

Assuming you are using systemd, copy the respondd.service file to /etc/systemd/system/. Open the copy and adapt the path to your checkout of the repository and the interface names in the line starting with ExecStart=. Afterwards, start the service and optionally set it to autostart:

systemctl daemon-reload
systemctl start respondd
# autostart on boot
systemctl enable respondd

Furthermore, you have to open UDP port 1001 in your IPv6 firewall for all mesh and B.A.T.M.A.N. advanced interfaces. Please don't open the port globally, as it can be used for traffic amplification attacks. You also might want to ratelimit it on the allowed interfaces for the same reason.

commandline options

Those are all available options (respondd --help):

      respondd.py -h
      respondd.py [-p <port>] [-g <group>] [-i [<group>%]<if0>] [-i [<group>%]<if1> ..] [-d <dir>] [-b <batman_iface>[:<mesh_ipv4>] [-n <domain code>] ..]

optional arguments:
  -h, --help            show this help message and exit
  -p <port>             port number to listen on (default 1001)
  -g <link local group>
                        link-local multicast group (default ff02::2:1001), set
                        to emtpy string to disable
  -s <site local group>
                        site-local multicast group (default ff05::2:1001), set
                        to empty string to disable
  -i <iface>            listening interface (default bat0), may be specified
                        multiple times
  -d <dir>              data provider directory (default: $PWD/providers)
  -b <iface>            batman-adv interface to answer for (default: bat0).
                        Specify once per domain
  -m <mesh_ipv4>        mesh ipv4 address
  -n <domain code>      Gateway domain_code for nodeinfo/system/domain_code


This is a possible configuration for a site with a single domain:

    `respondd.py -d /opt/mesh-announce/providers -i <your-clientbridge-if> -i <your-mesh-vpn-if> -b <your-batman-if> -m <mesh ipv4 address> -n <domain code>`

 * `<your-clientbridge-if>`: interfacename of mesh-bridge (for example br-ffXX)
 * `<your-mesh-vpn-if>`: interfacename of fastd or tuneldigger (for example ffXX-mvpn)
 * `<your-batman-if>`: B.A.T.M.A.N interfacename (usually bat-ffXX)
 * `<mesh ipv4 address>`: The ipv4 address of this gateway (usually the ip on interface `<your-clientbridge-if>`)  
    you can get the ip with `ip a s dev br-ffXX|grep inet|head -n1|cut -d" " -f 6|sed 's|/.*||g'`
 * `<domain code>`: The internal domain_code, identical with the gluon domain_name

The ipv4 address can be requested for example by
[ddhcpd](https://github.com/TobleMiner/gluon-sargon/blob/feature-respondd-gateway-update/ddhcpd/files/usr/sbin/ddhcpd-gateway-update#L3)
via

    `gluon-neighbour-info -p 1001 -d ff02::1 -i bat0 -r gateway`
    
This will request all json objects for all gateways. The json object for the
gateway can then be selected by the known macadress. The ip4 is stored in
`node_id.address.ipv4`.

Configuration for a multi-domain site (domains 'one', 'two' and 'three') might look like this:

    `respondd.py -d /opt/mesh-announce/providers -i meshvpn-one -i br-one -i bat-one -b bat-one -i meshvpn-two -i br-two -i bat-two -b bat-two -i meshvpn-three -i br-three -i bat-three -b bat-three`

In a more complex configuration involving the distributed DHCP deamon ddhcpd you might want to advertise different ipv4 gateways depending on the domain the query came from.
This can be realized by adding gateway address overrides to the corresponding batman interfaces:

    `respondd.py -d /opt/mesh-announce/providers -i meshvpn-one -i br-one -i bat-one -b bat-one:10.42.1.1 -i meshvpn-two -i br-two -i bat-two -b bat-two:10.42.2.1 -i meshvpn-three -i br-three -i bat-three -b bat-three:10.42.3.1`


### Debugging

When something goes wrong, the first step should be to look at the error log:

    sudo journalctl -u respondd.service