[ovs-git] [openvswitch/ovs] dd42d5: dpif-netlink-rtnl: Use 65000 instead of 65535 as t...

[GitHub]

  Branch: refs/heads/branch-2.9
  Home:   https://github.com/openvswitch/ovs
  Commit: dd42d544dfb5469d61d93216ef1631ff6e8aa034
      https://github.com/openvswitch/ovs/commit/dd42d544dfb5469d61d93216ef1631ff6e8aa034
  Author: Ben Pfaff <blp at ovn.org>
  Date:   2018-01-18 (Thu, 18 Jan 2018)

  Changed paths:
    M lib/dpif-netlink-rtnl.c

  Log Message:
  -----------
  dpif-netlink-rtnl: Use 65000 instead of 65535 as tunnel MTU.

Most of the existing tunnels accept 65535 for MTU and internally reduce it
to the maximum value actually supported.  However, in RTM_SETLINK calls,
at least GRE tunnels reject MTU larger than actually supported.  This
commit changes the MTU used in RTM_NEWLINK calls to use a value that should
be acceptable to all tunnels and yet does not noticeably reduce
performance.

(This code doesn't actually use RTM_SETLINK to change MTU yet, but that's
coming up.)

Suggested-by: Eric Garver <e at erig.me>
Suggested-at: https://mail.openvswitch.org/pipermail/ovs-dev/2018-January/343304.html
Signed-off-by: Ben Pfaff <blp at ovn.org>
Acked-by: Eric Garver <e at erig.me>
Tested-by: James Page <james.page at ubuntu.com>


  Commit: dd2e0fd456c2c9e6f160288f94259ac7f3ce3556
      https://github.com/openvswitch/ovs/commit/dd2e0fd456c2c9e6f160288f94259ac7f3ce3556
  Author: Ben Pfaff <blp at ovn.org>
  Date:   2018-01-18 (Thu, 18 Jan 2018)

  Changed paths:
    M lib/dpif-netlink-rtnl.c

  Log Message:
  -----------
  dpif-netlink-rtnl: Work around MTU bug in kernel GRE driver.

The kernel GRE driver ignores IFLA_MTU in RTM_NEWLINK requests and
overrides the MTU to 1472 bytes.  This commit works around the problem by
following up a request to create a GRE device with a second request to set
the MTU.

Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=1488484
Reported-by: Eric Garver <e at erig.me>
Reported-by: James Page <james.page at ubuntu.com>
Signed-off-by: Ben Pfaff <blp at ovn.org>
Acked-by: Eric Garver <e at erig.me>
Tested-by: James Page <james.page at ubuntu.com>


Compare: https://github.com/openvswitch/ovs/compare/ac964cceec77...dd2e0fd456c2