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  1. Feb 10, 2017
  3. Feb 09, 2017
    • Ido Schimmel's avatar
      mlxsw: spectrum_router: Don't reflect LINKDOWN nexthops · df6dd79b
      Ido Schimmel authored 
      

The kernel resolves the nexthops for a given route using
FIB_LOOKUP_IGNORE_LINKSTATE which means a notification can be sent for a
route with one of its nexthops being LINKDOWN.

In case IGNORE_ROUTES_WITH_LINKDOWN is set for the nexthop netdev, then
we shouldn't reflect the nexthop to the device's table.

Once the nexthop netdev's carrier goes up we'll be notified using NH_ADD
and reflect it to the device.

Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      df6dd79b
    • David S. Miller's avatar
      Merge branch 'mlxsw-Reflect-nexthop-status-changes' · d9e1661d
      David S. Miller authored 
      

Jiri Pirko says:

====================
mlxsw: Reflect nexthop status changes

Ido says:

When the kernel forwards IPv4 packets via multipath routes it doesn't
consider nexthops that are dead or linkdown. For example, if the nexthop
netdev is administratively down or doesn't have a carrier.

Devices capable of offloading such multipath routes need to be made
aware of changes in the reflected nexthops' status. Otherwise, the
device might forward packets via non-functional nexthops, resulting in
packet loss. This patchset aims to fix that.

The first 11 patches deal with the necessary restructuring in the
mlxsw driver, so that it's able to correctly add and remove nexthops
from the device's adjacency table.

The 12th patch adds the NH_{ADD,DEL} events to the FIB notification
chain. These notifications are sent whenever the kernel decides to add
or remove a nexthop from the forwarding plane.

Finally, the last three patches add support for these events in the
mlxsw driver, which is currently the only driver capable of offloading
multipath routes.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d9e1661d
    • Ido Schimmel's avatar
      mlxsw: spectrum_router: Flush resources when RIF is deleted · 9665b745
      Ido Schimmel authored 
      

When the last IP address is removed from a netdev, its RIF is deleted.
However, if user didn't first remove neighbours and nexthops using this
interface, then they would still be present in the device's tables.

Therefore, whenever a RIF is deleted, make sure all the neighbours and
nexthops (adjacency entries) using it are removed from the relevant
tables as well.

The action associated with any route using this RIF would be refreshed,
most likely to trap. If the kernel decides to remove the route (f.e.,
because all the nexthops are now DEAD), then an event would be sent,
causing the route to be removed from the device.

Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9665b745
    • Ido Schimmel's avatar
      mlxsw: spectrum_router: Reflect nexthop status changes · ad178c8e
      Ido Schimmel authored 
      

When a packet hits a multipath route in the device's routing table, a
hash is computed over its headers, which is then used to select the
appropriate nexthop from the device's adjacency table.

There are situations in which the kernel removes a nexthop from a
multipath route (e.g., no carrier) and the device should do the same.

Upon the reception of NH_{ADD,DEL} events, add or remove a nexthop from
the device's adjacency table and refresh all the routes using the
nexthop group. If all the nexthops of a multipath route are invalid,
then any packet hitting the route would be trapped to the CPU for
forwarding.

If all the nexthops are DEAD, then the kernel would remove the route
entirely. On the other hand, if all the nexthops are merely LINKDOWN,
then the kernel would keep the route and forward any incoming packet
using a different route.

While the last case might sound like a problem, it's expected that a
routing daemon running in user space would remove such a route from the
FIB as it's dumped with the DEAD flag set.

Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ad178c8e
    • Ido Schimmel's avatar
      ipv4: fib: Notify about nexthop status changes · 982acb97
      Ido Schimmel authored 
      

When a multipath route is hit the kernel doesn't consider nexthops that
are DEAD or LINKDOWN when IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN is set.
Devices that offload multipath routes need to be made aware of nexthop
status changes. Otherwise, the device will keep forwarding packets to
non-functional nexthops.

Add the FIB_EVENT_NH_{ADD,DEL} events to the fib notification chain,
which notify capable devices when they should add or delete a nexthop
from their tables.

Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Cc: David Ahern <dsa@cumulusnetworks.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Reviewed-by: default avatarAndy Gospodarek <gospo@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      982acb97