[ovs-dev] [PATCH v3] OVN: run local logical flows first in S_ROUTER_OUT_SNAT table

[Lorenzo Bianconi]

Run local logical flows first if the gw router port is scheduled
on the local chassis in order to properly manage snat traffic

Tested-by: Eran Kuris <ekuris at redhat.com>
Acked-by: Numan Siddique <nusiddiq at redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
---
Changes since v2:
- fix compilation error
Changes since v1:
- add priority change in ovn-northd.8.xml
---
 ovn/northd/ovn-northd.8.xml | 3 ++-
 ovn/northd/ovn-northd.c     | 7 +++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/ovn/northd/ovn-northd.8.xml b/ovn/northd/ovn-northd.8.xml
index 193aa210f..d2267de0e 100644
--- a/ovn/northd/ovn-northd.8.xml
+++ b/ovn/northd/ovn-northd.8.xml
@@ -2428,7 +2428,8 @@ nd_ns {
         <p>
           If the NAT rule cannot be handled in a distributed manner, then
           the flow above is only programmed on the
-          <code>redirect-chassis</code>.
+          <code>redirect-chassis</code> increasing flow priority by 128 in
+          order to be run first
         </p>
 
         <p>
diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
index ba2719321..ce382ac89 100644
--- a/ovn/northd/ovn-northd.c
+++ b/ovn/northd/ovn-northd.c
@@ -6634,6 +6634,8 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
                                   count_1bits(ntohl(mask)) + 1,
                                   ds_cstr(&match), ds_cstr(&actions));
                 } else {
+                    uint16_t priority = count_1bits(ntohl(mask)) + 1;
+
                     /* Distributed router. */
                     ds_clear(&match);
                     ds_put_format(&match, "ip && ip4.src == %s"
@@ -6643,6 +6645,7 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
                     if (!distributed && od->l3redirect_port) {
                         /* Flows for NAT rules that are centralized are only
                          * programmed on the "redirect-chassis". */
+                        priority += 128;
                         ds_put_format(&match, " && is_chassis_resident(%s)",
                                       od->l3redirect_port->json_key);
                     }
@@ -6657,8 +6660,8 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
                      * nat->logical_ip with the longest mask gets a higher
                      * priority. */
                     ovn_lflow_add(lflows, od, S_ROUTER_OUT_SNAT,
-                                  count_1bits(ntohl(mask)) + 1,
-                                  ds_cstr(&match), ds_cstr(&actions));
+                                  priority, ds_cstr(&match),
+                                  ds_cstr(&actions));
                 }
             }
 
-- 
2.21.0