manager: don't bring up master connections on devices that are not disconnected

Otherwise we're likely interfering with an in-progress activation.
Consider the following connections, first two being active:

  id=bond0a type=bond interface-name=bond0, (Active)
    id=dummy0a type=dummy interface-name=dummy0 master=bond0a, (Active)
  id=bond0b type=bond interface-name=bond0
    id=dummy0b type=dummy interface-name=dummy0 master=bond0b

Note there's two hierarchies with bond0 bond having a dummy0 port,
first one (bond0a, dummy0a) being active.

Suppose the users wants to bring the other one up (bond0b, dummy0b) and
does a "nmcli c up bond0b". This is what happens:

  1.) bond0b starts activation due to user request
  2.) bond0a starts deactivation due to new activation
  3.) dummy0 loses its master, begins deactivation
  4.) dummy0 finishes deactivation
  5.) both dummy0 being deactivated and bond0b check for slaves enqueues
      auto-activation check for dummy0
  6.) auto-activation picks dummy0a for dummy0
  7.) dummy0a begins activation
  8.) dummy0a looks for master connection, picks bond0a
  9.) bond0a starts activating on bond0, kicks bond0b away
  10.) bond0a and dummy0a end up finishing activation
  11.) Everybody unhappy :(

NM's auto-activation logic is only takes autoconnect priority into
account when figuring out a connection to activate and can't be expected
to bring up most sensible combination of connection when there's
multiple ones for the same devices with complex dependencies.

Nevertheless, it shouldn't ever undo the activations if the user is
bringing up the connections manually.

This patch prevents bringing up of master devices that are not
DISCONNECTED and therefore shouldn't be up for grabs. This was
previously done for hardware devices only whereas I believe it should be
the case for *all* realized devices.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager-ci/-/merge_requests/1172
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1364

1 files changed, 3 insertions, 5 deletions

diff --git a/src/core/nm-manager.c b/src/core/nm-manager.c
index e21048bf79..e198385c87 100644
--- a/src/core/nm-manager.c
+++ b/src/core/nm-manager.c
@@ -4608,11 +4608,9 @@ ensure_master_active_connection(NMManager            *self,
                     NULL))
                 continue;
 
-            if (!nm_device_is_software(candidate)) {
-                master_state = nm_device_get_state(candidate);
-                if (nm_device_is_real(candidate) && master_state != NM_DEVICE_STATE_DISCONNECTED)
-                    continue;
-            }
+            if (nm_device_is_real(candidate)
+                && nm_device_get_state(candidate) != NM_DEVICE_STATE_DISCONNECTED)
+                continue;
 
             master_ac = nm_manager_activate_connection(
                 self,