d096a4df48
Distros often have additional rules in the their iptabvles 'filter' table that do things like: -A FORWARD -j REJECT --reject-with icmp-host-prohibited docker, for example, gets around this by adding explicit rules to the filter table's FORWARD chain to allow traffic from the docker0 interface. Do that for a given host interface too, as a chained plugin.
firewall plugin
Overview
This plugin creates firewall rules to allow traffic to/from the host network interface given by "ifName". It does not create any network interfaces and therefore does not set up connectivity by itself. It is only useful when used in addition to other plugins.
Operation
The following network configuration file
{
"name": "mynet",
"type": "firewall",
"ifName": "cni0"
}
will allow the given interface to send/receive traffic via the host.
A successful result would simply be an empty result, unless a previous plugin passed a previous result, in which case this plugin will return that verbatim.
Backends
This plugin supports multiple firewall backends that implement the desired functionality.
Available backends include iptables and firewalld and may be selected with the backend key.
If no backend key is given, the plugin will use firewalld if the service exists on the D-Bus system bus.
If no firewalld service is found, it will fall back to iptables.
When the iptables backend is used, the above example will create two new iptables chains in the filter table and add rules that allow the given interface to send/receive traffic.
When the firewalld backend is used, the above example will place the cni0 interface into firewalld's trusted zone, allowing it to send/receive traffic.