[ovs-git] [openvswitch/ovs] 995933: ovn: Allow DNS lookups over IPv6

[GitHub]

  Branch: refs/heads/branch-2.8
  Home:   https://github.com/openvswitch/ovs
  Commit: 995933f224d3f682541ef060a949986620df5f05
      https://github.com/openvswitch/ovs/commit/995933f224d3f682541ef060a949986620df5f05
  Author: Mark Michelson <mmichels at redhat.com>
  Date:   2018-02-09 (Fri, 09 Feb 2018)

  Changed paths:
    M ovn/controller/pinctrl.c
    M tests/ovn.at

  Log Message:
  -----------
  ovn: Allow DNS lookups over IPv6

There was a bug in DNS request handling where the incoming packet was
assumed to be IPv4.

The result was that for the outgoing packet, we would attempt to write
the IPv4 checksum and total length into what was actually an IPv6
header. This resulted in the source IPv6 address getting corrupted.
Later, the source and destination IPv6 addresses would get swapped,
resulting in the DNS response being sent to a nonsense destination.

With this change, we check the ethertype of the packet to determine what
l3 information to write, and where to write it. A test is also included
that verifies that this works as expected.

Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=1539608
Signed-off-by: Mark Michelson <mmichels at redhat.com>
Signed-off-by: Ben Pfaff <blp at ovn.org>