In my use case, I need bidirectional communication between containers while setting -icc=false.

The newly introduced -link option allows to set a one-directional parent-child relationship between an already running container (the child) and the container being started (the parent). When starting the parent, I need to be able to tell docker that the child shall be able to access the parent as well. Clearly, service discovery through environment variables would not be possible in this case, but allowing network traffic should be enough.

I propose to add an additional option (in the form of -invlink, -allow, or similar) which takes a container ID/name and sets up a child-parent relationship.

Implementation wise, this would be the same as calling the Link.toggle method with parent and child inverted.