[ovs-dev] [PATCH] utilities/ovs-ctl: Force removal of ip_gre/gre

[Gregory Rose]

On 5/31/2018 2:31 PM, Guru Shetty wrote:
>
>
> On 31 May 2018 at 14:20, Greg Rose <gvrose8192 at gmail.com 
> <mailto:gvrose8192 at gmail.com>> wrote:
>
>     On Linux kernels older than 4.16 the user cannot take advantage of
>     OVS ERSPAN features if the older ip_gre and gre kernel modules are
>     loaded.  In addition, the openvswitch kernel module will fail to
>     load because it cannot grab the IPPROTO_GRE inet protocol handler
>     since the gre kernel module has already taken it.
>
>     Update the force_reload_kmod() script function to force removal
>     of the ip_gre and gre built-in kernel modules so that the openvswitch
>     kernel module can load and provide support for ERSPAN.
>
>     Signed-off-by: Greg Rose <gvrose8192 at gmail.com
>     <mailto:gvrose8192 at gmail.com>>
>
>
> There was some logic that was added in commit 
> 921c370a9df520c3784db03bdb363660c148235e, wherein ovs-vswitchd will 
> check for the presence of some capability and will load either 
> upstream linux geneve module or OVS repo geneve module. Does that not 
> conflict with this one? (See f658f95e735c29c6c7c319e147b01ea266fd8a88 
> for GRE specific commit). I don't understand the subtleties involved here.
>

Good catch.  That should be modified to check for IFLA_GRE_ERSPAN_HWID - 
if that's not supported then
we don't want the built-in gre kernel module.

I'll see if I can figure that code out and come up with a patch.

Thanks,

- Greg

>     ---
>      utilities/ovs-lib.in <http://ovs-lib.in> | 8 ++++++++
>      1 file changed, 8 insertions(+)
>
>     diff --git a/utilities/ovs-lib.in <http://ovs-lib.in>
>     b/utilities/ovs-lib.in <http://ovs-lib.in>
>     index 4c3ad0f..5ba4f8b 100644
>     --- a/utilities/ovs-lib.in <http://ovs-lib.in>
>     +++ b/utilities/ovs-lib.in <http://ovs-lib.in>
>     @@ -622,6 +622,14 @@ force_reload_kmod () {
>              action "Removing $vport module" rmmod $vport
>          done
>
>     +    if test -e /sys/module/ip_gre; then
>     +        action "Forcing removal of ip_gre module" rmmod ip_gre
>     +    fi
>     +
>     +    if test -e /sys/module/gre; then
>     +        action "Forcing removal of gre module" rmmod gre
>     +    fi
>     +
>          if test -e /sys/module/openvswitch; then
>              action "Removing openvswitch module" rmmod openvswitch
>          fi
>     -- 
>     1.8.3.1
>
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