add_addr: `too many addresses or duplicate one: Invalid argument` error when launching a new docker image

[matttbe]

With mptcpd 0.11, this error message is printed each time I run a new docker image:

add_addr: too many addresses or duplicate one: Invalid argument

It is easy to reproduce on my side:

$ sudo journalctl -f | grep mptcpd &
$ docker run -it ubuntu true
Dec 28 17:53:12 <host> mptcpd[1245210]: add_addr: too many addresses or duplicate one: Invalid argument

I guess it is because Docker create a new veth interface each time with only a IPv6 link local address.

Using Ubuntu 23.04 Devel.