Removing interface from bridge

[Gabriele Baldoni]

Hi,

It is possible to remove an interface from a bridge after we have assigned it?

Nowadays I can easily assign an interface to a bridge by doing like this:

let (connection, handle, _) = new_connection().unwrap();
            tokio::spawn(connection);
            let mut links = handle.link().get().set_name_filter(iface).execute();
            if let Some(link) = links
                .try_next()
                .await
                .map_err(|e| FError::NetworkingError(format!("{}", e)))?
            {
                let mut masters = handle.link().get().set_name_filter(master).execute();
                if let Some(master) = masters
                    .try_next()
                    .await
                    .map_err(|e| FError::NetworkingError(format!("{}", e)))?
                {
                    handle
                        .link()
                        .set(link.header.index)
                        .master(master.header.index)
                        .execute()
                        .await
                        .map_err(|e| FError::NetworkingError(format!("{}", e)))
                } else {
                    log::error!("set_iface_master master not found");
                    Err(FError::NotFound)
                }
            } else {
                log::error!("set_iface_master iface not found");
                Err(FError::NotFound)
            }

But I see that in set there is nothing like no_master() that would be similar to ip link set IFACE nomaster.

So it is possible or it is something actually missing?

[Fernando Fernández Mancera]

I've looked at the code and it seems it is missing. If not missing we should document this.

[Gabriele Baldoni]

I will check what ip link set <iface> nomaster does and I'll try to implement it.

[Gabriele Baldoni]

This comment is to keep track of the investigation.

From an strace on ip link set <dev> nomaster

I see this message sent to netlink.

...
28779 sendmsg(3, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base={{len=40, type=RTM_NEWLINK, flags=NLM_F_REQUEST|NLM_F_ACK, seq=1607600465, pid=0}, {ifi_family=AF_UNSPEC, ifi_type=ARPHRD_NETROM, ifi_index=if_nametoindex("d0"), ifi_flags=0, ifi_change=0}, {{nla_len=8, nla_type=IFLA_MASTER}, 0}}, iov_len=40}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 40
....

Thus seems that is sufficient to set the IFLA_MASTER to 0 to remove the master