[ovs-git] [openvswitch/ovs] 5c2c38: conntrack: Reset ct_state when entering a new zone.

Dumitru Ceara noreply at github.com
Tue Mar 24 14:51:22 UTC 2020

  Branch: refs/heads/branch-2.10
  Home:   https://github.com/openvswitch/ovs
  Commit: 5c2c38bbb9125e9ad422a35e4ccb4d660ced109b
  Author: Dumitru Ceara <dceara at redhat.com>
  Date:   2020-03-23 (Mon, 23 Mar 2020)

  Changed paths:
    M lib/conntrack.c

  Log Message:
  conntrack: Reset ct_state when entering a new zone.

When a new conntrack zone is entered, the ct_state field is zeroed in
order to avoid using state information from different zones.

One such scenario is when a packet is double NATed. Assuming two zones
and 3 flows performing the following actions in order on the packet:
1. ct(zone=5,nat), recirc
2. ct(zone=1), recirc
3. ct(zone=1,nat)

If at step #1 the packet matches an existing NAT entry, it will get
translated and pkt->md.ct_state is set to CS_DST_NAT or CS_SRC_NAT.
At step #2 the new tuple might match an existing connection and
pkt->md.ct_zone is set to 1.
If at step #3 the packet matches an existing NAT entry in zone 1,
handle_nat() will be called to perform the translation but it will
return early because the packet's zone matches the conntrack zone and
the ct_state field still contains CS_DST_NAT or CS_SRC_NAT from the
translations in zone 5.

In order to reliably detect when a packet enters a new conntrack zone
we also need to make sure that the pkt->md.ct_zone is properly
initialized if pkt->md.ct_state is non-zero. This already happens for
most cases. The only exception is when matched conntrack connection is
of type CT_CONN_TYPE_UN_NAT and the master connection is missing. To
cover this path we now call write_ct_md() in that case too. Remove
setting the CS_TRACKED flag as in this case as it will be done by the
new call to write_ct_md().

CC: Darrell Ball <dlu998 at gmail.com>
Fixes: 286de2729955 ("dpdk: Userspace Datapath: Introduce NAT Support.")
Acked-by: Ilya Maximets <i.maximets at ovn.org>
Acked-by: Aaron Conole <aconole at redhat.com>
Signed-off-by: Dumitru Ceara <dceara at redhat.com>
Signed-off-by: Ilya Maximets <i.maximets at ovn.org>

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