ofctrl: Prevent conjunction duplication

During ofctrl_add_or_append_flow we are able to combine
two flows with same match but different conjunctions.
However, the function didn't check if the conjunctions already
exist in the installed flow, which could result in conjunction
duplication and the flow would grow infinitely e.g.
actions=conjunction(1,1/2), conjunction(1,1/2)

Make sure that we add only conjunctions that are not present
in the already existing flow.

Reported-at: https://bugzilla.redhat.com/2175928
Acked-by: Mark Michelson <mmichels@redhat.com>
Signed-off-by: Ales Musil <amusil@redhat.com>
Signed-off-by: Mark Michelson <mmichels@redhat.com>

controller/ofctrl.c

@@ -1276,6 +1276,37 @@ ofctrl_add_flow_metered(struct ovn_desired_flow_table *desired_flows,
                                       meter_id, as_info, true);
 }
 
+struct ofpact_ref {
+    struct hmap_node hmap_node;
+    struct ofpact *ofpact;
+};
+
+static struct ofpact_ref *
+ofpact_ref_find(const struct hmap *refs, const struct ofpact *ofpact)
+{
+    uint32_t hash = hash_bytes(ofpact, ofpact->len, 0);
+
+    struct ofpact_ref *ref;
+    HMAP_FOR_EACH_WITH_HASH (ref, hmap_node, hash, refs) {
+        if (ofpacts_equal(ref->ofpact, ref->ofpact->len,
+                          ofpact, ofpact->len)) {
+            return ref;
+        }
+    }
+
+    return NULL;
+}
+
+static void
+ofpact_refs_destroy(struct hmap *refs)
+{
+    struct ofpact_ref *ref;
+    HMAP_FOR_EACH_POP (ref, hmap_node, refs) {
+        free(ref);
+    }
+    hmap_destroy(refs);
+}
+
 /* Either add a new flow, or append actions on an existing flow. If the
  * flow existed, a new link will also be created between the new sb_uuid
  * and the existing flow. */
@@ -1295,6 +1326,21 @@ ofctrl_add_or_append_flow(struct ovn_desired_flow_table *desired_flows,
                            meter_id);
     existing = desired_flow_lookup_conjunctive(desired_flows, &f->flow);
     if (existing) {
+        struct hmap existing_conj = HMAP_INITIALIZER(&existing_conj);
+
+        struct ofpact *ofpact;
+        OFPACT_FOR_EACH (ofpact, existing->flow.ofpacts,
+                         existing->flow.ofpacts_len) {
+            if (ofpact->type != OFPACT_CONJUNCTION) {
+                continue;
+            }
+
+            struct ofpact_ref *ref = xmalloc(sizeof *ref);
+            ref->ofpact = ofpact;
+            uint32_t hash = hash_bytes(ofpact, ofpact->len, 0);
+            hmap_insert(&existing_conj, &ref->hmap_node, hash);
+        }
+
         /* There's already a flow with this particular match and action
          * 'conjunction'. Append the action to that flow rather than
          * adding a new flow.
@@ -1304,7 +1350,15 @@ ofctrl_add_or_append_flow(struct ovn_desired_flow_table *desired_flows,
         ofpbuf_use_stub(&compound, compound_stub, sizeof(compound_stub));
         ofpbuf_put(&compound, existing->flow.ofpacts,
                    existing->flow.ofpacts_len);
-        ofpbuf_put(&compound, f->flow.ofpacts, f->flow.ofpacts_len);
+
+        OFPACT_FOR_EACH (ofpact, f->flow.ofpacts, f->flow.ofpacts_len) {
+            if (ofpact->type != OFPACT_CONJUNCTION ||
+                !ofpact_ref_find(&existing_conj, ofpact)) {
+                ofpbuf_put(&compound, ofpact, OFPACT_ALIGN(ofpact->len));
+            }
+        }
+
+        ofpact_refs_destroy(&existing_conj);
 
         mem_stats.desired_flow_usage -= desired_flow_size(existing);
         free(existing->flow.ofpacts);