[ovs-dev] [PATCH] odp-util: Remove unnecessary TOS ECN bits rewrite for tunnels

Jianbo Liu jianbol at mellanox.com
Thu Apr 26 05:54:48 UTC 2018


For tunnels, TOS ECN bits are never wildcard for the reason that they
are always inherited. OVS will create a rewrite action if we add rule
to modify other IP headers. But it also adds an extra ECN rewrite for
the action because of this ECN un-wildcarding.

It seems no error because the ECN bits to be changed are same in this
case. But as rule can't be offloaded to hardware, the unnecssary ECN
rewrite should be removed.

Signed-off-by: Jianbo Liu <jianbol at mellanox.com>
Reviewed-by: Paul Blakey <paulb at mellanox.com>
Reviewed-by: Roi Dayan <roid at mellanox.com>
---
 lib/odp-util.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/odp-util.c b/lib/odp-util.c
index 6db241a..91bf5d6 100644
--- a/lib/odp-util.c
+++ b/lib/odp-util.c
@@ -6962,6 +6962,10 @@ commit_set_ipv4_action(const struct flow *flow, struct flow *base_flow,
     mask.ipv4_proto = 0;        /* Not writeable. */
     mask.ipv4_frag = 0;         /* Not writable. */
 
+    if (flow_tnl_dst_is_set(&base_flow->tunnel) &&
+        ((base_flow->nw_tos ^ flow->nw_tos) & IP_ECN_MASK) == 0)
+        mask.ipv4_tos &= ~IP_ECN_MASK;
+
     if (commit(OVS_KEY_ATTR_IPV4, use_masked, &key, &base, &mask, sizeof key,
                odp_actions)) {
         put_ipv4_key(&base, base_flow, false);
@@ -7012,6 +7016,10 @@ commit_set_ipv6_action(const struct flow *flow, struct flow *base_flow,
     mask.ipv6_proto = 0;        /* Not writeable. */
     mask.ipv6_frag = 0;         /* Not writable. */
 
+    if (flow_tnl_dst_is_set(&base_flow->tunnel) &&
+        ((base_flow->nw_tos ^ flow->nw_tos) & IP_ECN_MASK) == 0)
+        mask.ipv6_tclass &= ~IP_ECN_MASK;
+
     if (commit(OVS_KEY_ATTR_IPV6, use_masked, &key, &base, &mask, sizeof key,
                odp_actions)) {
         put_ipv6_key(&base, base_flow, false);
-- 
2.9.5



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