[ovs-dev] [PATCH v4 05/10] ofctrl_check_and_add_flow: Replace the actions of an existing flow if actions have changed.

[numans at ovn.org]

From: Numan Siddique <numans at ovn.org>

If ofctrl_check_and_add_flow(F') is called where flow F' has match-actions (M, A2)
and if there already exists a flow F with match-actions (M, A1) in the desired flow
table, then this function  doesn't update the existing flow F with new actions
actions A2.

This patch is required for the upcoming patch in this series which
adds incremental processing for OVS interface in the flow output stage.
Since we will be not be clearing the flow output data if these changes
are handled incrementally, some of the existing flows will be updated
with new actions. One such example would be flows in physical
table OFTABLE_LOCAL_OUTPUT (table 33). And this patch is required to
update such flows. Otherwise we will have incomplete actions installed.

Signed-off-by: Numan Siddique <numans at ovn.org>
---
 controller/ofctrl.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/controller/ofctrl.c b/controller/ofctrl.c
index 485a857d1..3b257be35 100644
--- a/controller/ofctrl.c
+++ b/controller/ofctrl.c
@@ -667,14 +667,23 @@ ofctrl_check_and_add_flow(struct ovn_desired_flow_table *flow_table,
 
     ovn_flow_log(f, "ofctrl_add_flow");
 
-    if (ovn_flow_lookup(&flow_table->match_flow_table, f, true)) {
-        if (log_duplicate_flow) {
-            static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
-            if (!VLOG_DROP_DBG(&rl)) {
-                char *s = ovn_flow_to_string(f);
-                VLOG_DBG("dropping duplicate flow: %s", s);
-                free(s);
+    struct ovn_flow *existing_f =
+        ovn_flow_lookup(&flow_table->match_flow_table, f, true);
+    if (existing_f) {
+        if (ofpacts_equal(f->ofpacts, f->ofpacts_len,
+                          existing_f->ofpacts, existing_f->ofpacts_len)) {
+            if (log_duplicate_flow) {
+                static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
+                if (!VLOG_DROP_DBG(&rl)) {
+                    char *s = ovn_flow_to_string(f);
+                    VLOG_DBG("dropping duplicate flow: %s", s);
+                    free(s);
+                }
             }
+        } else {
+            free(existing_f->ofpacts);
+            existing_f->ofpacts = xmemdup(f->ofpacts, f->ofpacts_len);
+            existing_f->ofpacts_len = f->ofpacts_len;
         }
         ovn_flow_destroy(f);
         return;
-- 
2.25.4