Handle outbound_direction_lookup for DASH_APPLIANCE_TABLE (#3571)

* Handle outbound_direction_lookup for DASH_APPLIANCE_TABLE
 * If no value is specified, use a default value of SAI_DASH_ENI_MAC_OVERRIDE_TYPE_SRC_MAC, else use the specified value.

 Ref: sonic-net/SONiC#1911

Author: prabhataravind

orchagent/dash/dashorch.cpp

@@ -40,6 +40,12 @@ extern bool gTraditionalFlexCounter;
 
 #define FLEX_COUNTER_UPD_INTERVAL 1
 
+static std::unordered_map<string, sai_dash_eni_mac_override_type_t> sMacOverride =
+{
+    { "src_mac", SAI_DASH_ENI_MAC_OVERRIDE_TYPE_SRC_MAC},
+    { "dst_mac", SAI_DASH_ENI_MAC_OVERRIDE_TYPE_DST_MAC}
+};
+
 DashOrch::DashOrch(DBConnector *db, vector<string> &tableName, ZmqServer *zmqServer) :
     ZmqOrch(db, tableName, zmqServer),
     m_eni_stat_manager(ENI_STAT_COUNTER_FLEX_COUNTER_GROUP, StatsMode::READ, ENI_STAT_FLEX_COUNTER_POLLING_INTERVAL_MS, false)
@@ -158,7 +164,14 @@ bool DashOrch::addApplianceEntry(const string& appliance_id, const dash::applian
     direction_lookup_attrs.push_back(appliance_attr);
 
     appliance_attr.id = SAI_DIRECTION_LOOKUP_ENTRY_ATTR_DASH_ENI_MAC_OVERRIDE_TYPE;
-    appliance_attr.value.u32 = SAI_DASH_ENI_MAC_OVERRIDE_TYPE_DST_MAC;
+    if (entry.has_outbound_direction_lookup())
+    {
+        appliance_attr.value.u32 = sMacOverride[entry.outbound_direction_lookup()];
+    }
+    else
+    {
+        appliance_attr.value.u32 = SAI_DASH_ENI_MAC_OVERRIDE_TYPE_SRC_MAC;
+    }
     direction_lookup_attrs.push_back(appliance_attr);
 
     status = sai_dash_direction_lookup_api->create_direction_lookup_entry(&direction_lookup_entry,

tests/dash/test_dash_vnet.py

@@ -49,6 +49,21 @@ def test_appliance(self, dash_db: DashDB):
         self.sip = "10.0.0.1"
         self.vm_vni = "4321"
         self.local_region_id = "10"
+
+        # verify behavior when outbound_direction_lookup is specified
+        pb = Appliance()
+        pb.sip.ipv4 = socket.htonl(int(ipaddress.ip_address(self.sip)))
+        pb.vm_vni = int(self.vm_vni)
+        pb.local_region_id = int(self.local_region_id)
+        pb.outbound_direction_lookup = "dst_mac"
+        dash_db.create_appliance(self.appliance_id, {"pb": pb.SerializeToString()})
+        direction_keys = dash_db.wait_for_asic_db_keys(ASIC_DIRECTION_LOOKUP_TABLE)
+        dl_attrs = dash_db.get_asic_db_entry(ASIC_DIRECTION_LOOKUP_TABLE, direction_keys[0])
+        assert_sai_attribute_exists("SAI_DIRECTION_LOOKUP_ENTRY_ATTR_ACTION", dl_attrs, "SAI_DIRECTION_LOOKUP_ENTRY_ACTION_SET_OUTBOUND_DIRECTION")
+        assert_sai_attribute_exists("SAI_DIRECTION_LOOKUP_ENTRY_ATTR_DASH_ENI_MAC_OVERRIDE_TYPE", dl_attrs, "SAI_DASH_ENI_MAC_OVERRIDE_TYPE_DST_MAC")
+        dash_db.remove_appliance(self.appliance_id)
+        time.sleep(2)
+
         pb = Appliance()
         pb.sip.ipv4 = socket.htonl(int(ipaddress.ip_address(self.sip)))
         pb.vm_vni = int(self.vm_vni)
@@ -62,7 +77,8 @@ def test_appliance(self, dash_db: DashDB):
         direction_keys = dash_db.wait_for_asic_db_keys(ASIC_DIRECTION_LOOKUP_TABLE)
         dl_attrs = dash_db.get_asic_db_entry(ASIC_DIRECTION_LOOKUP_TABLE, direction_keys[0])
         assert_sai_attribute_exists("SAI_DIRECTION_LOOKUP_ENTRY_ATTR_ACTION", dl_attrs, "SAI_DIRECTION_LOOKUP_ENTRY_ACTION_SET_OUTBOUND_DIRECTION")
-        assert_sai_attribute_exists("SAI_DIRECTION_LOOKUP_ENTRY_ATTR_DASH_ENI_MAC_OVERRIDE_TYPE", dl_attrs, "SAI_DASH_ENI_MAC_OVERRIDE_TYPE_DST_MAC")
+        # When outbound_direction_lookup is not specified, src mac is used by default
+        assert_sai_attribute_exists("SAI_DIRECTION_LOOKUP_ENTRY_ATTR_DASH_ENI_MAC_OVERRIDE_TYPE", dl_attrs, "SAI_DASH_ENI_MAC_OVERRIDE_TYPE_SRC_MAC")
 
         vip_keys = dash_db.wait_for_asic_db_keys(ASIC_VIP_TABLE)
         vip_attrs = dash_db.get_asic_db_entry(ASIC_VIP_TABLE, vip_keys[0])