[ovs-dev] [PATCH] odp-execute: Extract l2 padding while executing check_pkt_len action.

Ilya Maximets i.maximets at ovn.org
Thu Jun 11 10:02:31 UTC 2020

If dp-packet contains l2 padding its size will be larger than the
actual size of a payload and action will work incorrectly.

Padding could be set during miniflow_extract() if detected.

CC: Numan Siddique <nusiddiq at redhat.com>
Fixes: 5b34f8fc3b38 ("Add a new OVS action check_pkt_larger")
Reported-by: Miroslav Kubiczek <miroslav.kubiczek at adaptivemobile.com>
Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2020-May/050157.html
Signed-off-by: Ilya Maximets <i.maximets at ovn.org>

I didn't test this, only checked existing unit tests.

Miroslav, could you, please, check if this works in your case?

It might be also good to write some unit test for this.

 lib/odp-execute.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/odp-execute.c b/lib/odp-execute.c
index 6018e378a..548083cef 100644
--- a/lib/odp-execute.c
+++ b/lib/odp-execute.c
@@ -761,10 +761,10 @@ odp_execute_check_pkt_len(void *dp, struct dp_packet *packet, bool steal,
     const struct nlattr *a;
     struct dp_packet_batch pb;
+    uint32_t size = dp_packet_size(packet) - dp_packet_l2_pad_size(packet);
-    bool is_greater = dp_packet_size(packet) > nl_attr_get_u16(a);
-    if (is_greater) {
+    if (size > nl_attr_get_u16(a)) {
     } else {

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