feat(ble_mesh): Miscellaneous updates for mesh kconfig, relay related

components/bt/esp_ble_mesh/Kconfig.in

@@ -545,6 +545,20 @@ if BLE_MESH
             Provisioner can provision up to 20 nodes and each node contains two elements,
             then the replay protection list size of Provisioner should be at least 40.
 
+    config BLE_MESH_NOT_RELAY_REPLAY_MSG
+        bool "Not relay replayed messages in a mesh network"
+        depends on BLE_MESH_EXPERIMENTAL
+        default n
+        help
+            There may be many expired messages in a complex mesh network that would be
+            considered replayed messages.
+            Enable this option will refuse to relay such messages, which could help to
+            reduce invalid packets in the mesh network.
+            However, it should be noted that enabling this option may result in packet
+            loss in certain environments.
+            Therefore, users need to decide whether to enable this option according to
+            the actual usage situation.
+
     config BLE_MESH_MSG_CACHE_SIZE
         int "Network message cache size"
         default 10
@@ -1248,4 +1262,12 @@ if BLE_MESH
 
     endmenu
 
+    config BLE_MESH_EXPERIMENTAL
+        bool "Make BLE Mesh experimental features visible"
+        default n
+        help
+            Make BLE Mesh Experimental features visible.
+            Experimental features list:
+            - CONFIG_BLE_MESH_NOT_RELAY_REPLAY_MSG
+
 endif # BLE_MESH

components/bt/esp_ble_mesh/mesh_core/net.c

@@ -2,7 +2,7 @@
 
 /*
  * SPDX-FileCopyrightText: 2017 Intel Corporation
- * SPDX-FileContributor: 2018-2021 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileContributor: 2018-2023 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -1265,7 +1265,7 @@ static void bt_mesh_net_relay(struct net_buf_simple *sbuf,
 #endif
 
     if (!buf) {
-        BT_ERR("Out of relay buffers");
+        BT_INFO("Out of relay buffers");
         return;
     }
 
@@ -1509,7 +1509,11 @@ void bt_mesh_net_recv(struct net_buf_simple *data, int8_t rssi,
      * was neither a local element nor an LPN we're Friends for.
      */
     if (!BLE_MESH_ADDR_IS_UNICAST(rx.ctx.recv_dst) ||
-            (!rx.local_match && !rx.friend_match)) {
+        (!rx.local_match && !rx.friend_match
+#if CONFIG_BLE_MESH_NOT_RELAY_REPLAY_MSG
+        && !rx.replay_msg
+#endif
+        )) {
         net_buf_simple_restore(&buf, &state);
         bt_mesh_net_relay(&buf, &rx);
     }

components/bt/esp_ble_mesh/mesh_core/net.h

@@ -294,6 +294,9 @@ struct bt_mesh_net_rx {
              ctl:1,          /* Network Control */
              net_if:2,       /* Network interface */
              local_match:1,  /* Matched a local element */
+#if CONFIG_BLE_MESH_NOT_RELAY_REPLAY_MSG
+             replay_msg:1,   /* Replayed messages */
+#endif
              friend_match:1; /* Matched an LPN we're friends for */
     uint16_t msg_cache_idx;  /* Index of entry in message cache */
 };

components/bt/esp_ble_mesh/mesh_core/transport.c

@@ -711,6 +711,9 @@ bool bt_mesh_rpl_check(struct bt_mesh_net_rx *rx, struct bt_mesh_rpl **match)
 
                 return false;
             } else {
+#if CONFIG_BLE_MESH_NOT_RELAY_REPLAY_MSG
+                rx->replay_msg = 1;
+#endif
                 return true;
             }
         }