mlxsw: Manage RIF across PVID changes

The mlxsw driver currently makes the assumption that the user applies configuration in a bottom-up manner. Thus netdevices need to be added to the bridge before IP addresses are configured on that bridge or SVI added on top of it. Enslaving a netdevice to another netdevice that already has uppers is in fact forbidden by mlxsw for this reason. Despite this safety, it is rather easy to get into situations where the offloaded configuration is just plain wrong.

As an example, take a front panel port, configure an IP address: it gets a RIF. Now enslave the port to the bridge, and the RIF is gone. Remove the port from the bridge again, but the RIF never comes back. There is a number of similar situations, where changing the configuration there and back utterly breaks the offload.

The situation is going to be made better by implementing a range of replays and post-hoc offloads.

In this patch set, address the ordering issues related to creation of bridge RIFs. Currently, mlxsw has several shortcomings with regards to RIF handling due to PVID changes:

- In order to cause RIF for a bridge device to be created, the user is expected first to set PVID, then to add an IP address. The reverse ordering is disallowed, which is not very user-friendly.

- When such bridge gets a VLAN upper whose VID was the same as the existing PVID, and this VLAN netdevice gets an IP address, a RIF is created for this netdevice. The new RIF is then assigned to the 802.1Q FID for the given VID. This results in a working configuration. However, then, when the VLAN netdevice is removed again, the RIF for the bridge itself is never reassociated to the PVID.

- PVID cannot be changed once the bridge has uppers. Presumably this is because the driver does not manage RIFs properly in face of PVID changes. However, as the previous point shows, it is still possible to get into invalid configurations.

This patch set addresses these issues and relaxes some of the ordering requirements that mlxsw had. The patch set proceeds as follows:

- In patch #1, pass extack to mlxsw_sp_br_ban_rif_pvid_change()

- To relax ordering between setting PVID and adding an IP address to a bridge, mlxsw must be able to request that a RIF is created with a given VLAN ID, instead of trying to deduce it from the current netdevice settings, which do not reflect the user-requested values yet. This is done in patches #2 and #3.

- Similarly, mlxsw_sp_inetaddr_bridge_event() will need to make decisions based on the user-requested value of PVID, not the current value. Thus in patches #4 and #5, add a new argument which carries the requested PVID value.

- Finally in patch #6 relax the ban on PVID changes when a bridge has uppers. Instead, add the logic necessary for creation of a RIF as a result of PVID change.

- Relevant selftests are presented afterwards. In patch #7 a preparatory helper is added to lib.sh. Patches #8, #9, #10 and #11 include selftests themselves.

Petr Machata (11):
mlxsw: spectrum_switchdev: Pass extack to
mlxsw_sp_br_ban_rif_pvid_change()
mlxsw: spectrum_router: Pass struct mlxsw_sp_rif_params to fid_get
mlxsw: spectrum_router: Take VID for VLAN FIDs from RIF params
mlxsw: spectrum_router: Adjust mlxsw_sp_inetaddr_vlan_event() coding
style
mlxsw: spectrum_router: mlxsw_sp_inetaddr_bridge_event: Add an
argument
mlxsw: spectrum_switchdev: Manage RIFs on PVID change
selftests: forwarding: lib: Add ping6_, ping_test_fails()
selftests: router_bridge: Add tests to remove and add PVID
selftests: router_bridge_vlan: Add PVID change test
selftests: router_bridge_vlan_upper_pvid: Add a new selftest
selftests: router_bridge_pvid_vlan_upper: Add a new selftest

 .../ethernet/mellanox/mlxsw/spectrum_router.c | 169 +++++++++++++++--
 .../ethernet/mellanox/mlxsw/spectrum_router.h |   4 +
 .../mellanox/mlxsw/spectrum_switchdev.c       |  32 +---
 .../testing/selftests/net/forwarding/Makefile |   2 +
 tools/testing/selftests/net/forwarding/lib.sh |  18 ++
 .../selftests/net/forwarding/router_bridge.sh |  50 +++++
 .../router_bridge_pvid_vlan_upper.sh          | 155 ++++++++++++++++
 .../net/forwarding/router_bridge_vlan.sh      | 100 ++++++++--
 .../router_bridge_vlan_upper_pvid.sh          | 171 ++++++++++++++++++
 9 files changed, 643 insertions(+), 58 deletions(-)
 create mode 100755 tools/testing/selftests/net/forwarding/router_bridge_pvid_vlan_upper.sh
 create mode 100755 tools/testing/selftests/net/forwarding/router_bridge_vlan_upper_pvid.sh

2.40.1