3 files changed, 54 insertions, 0 deletions
diff --git a/components/net/lwip/Kconfig b/components/net/lwip/Kconfig
index 9a1096e8ec..d98388b4ae 100644
--- a/components/net/lwip/Kconfig
+++ b/components/net/lwip/Kconfig
@@ -243,6 +243,13 @@ if RT_USING_LWIP
         bool "Enable netif loopback"
         default n
 
+    config RT_LWIP_USING_LOOPBACK
+        bool "Enable lwIP loopback network interface"
+        depends on RT_USING_NETDEV
+        select RT_LWIP_NETIF_LOOPBACK
+        default y if RT_USING_SMART
+        default n
+
     config LWIP_NETIF_LOOPBACK
         int
         default 1 if RT_LWIP_NETIF_LOOPBACK
diff --git a/components/net/lwip/port/ethernetif.c b/components/net/lwip/port/ethernetif.c
index ecb04a5492..208259386a 100644
--- a/components/net/lwip/port/ethernetif.c
+++ b/components/net/lwip/port/ethernetif.c
@@ -447,6 +447,44 @@ static void netdev_del(struct netif *lwip_netif)
     netdev_unregister(netdev);
     rt_free(netdev);
 }
+
+#ifdef RT_LWIP_USING_LOOPBACK
+static int lwip_loopback_init(void)
+{
+    struct netif *netif = netif_find("lo0");
+    struct netdev *netdev;
+    err_t result;
+
+    if (netif == RT_NULL)
+    {
+        return -RT_ERROR;
+    }
+
+    netif->mtu = 65535;
+    if (netdev_add(netif) != RT_EOK)
+    {
+        return -RT_ERROR;
+    }
+
+    result = netifapi_netif_set_link_up(netif);
+    if (result == ERR_OK && netif_default == RT_NULL)
+    {
+        result = netifapi_netif_set_default(netif);
+    }
+    if (result != ERR_OK)
+    {
+        netdev_del(netif);
+        return -RT_ERROR;
+    }
+
+    netdev = netdev_get_by_name("lo");
+    netdev_low_level_set_dhcp_status(netdev, RT_FALSE);
+    netdev_low_level_set_status(netdev, RT_TRUE);
+    netdev_low_level_set_link_status(netdev, RT_TRUE);
+    return RT_EOK;
+}
+INIT_APP_EXPORT(lwip_loopback_init);
+#endif /* RT_LWIP_USING_LOOPBACK */
 #endif /* RT_USING_NETDEV */
 
 static err_t ethernetif_linkoutput(struct netif *netif, struct pbuf *p)
diff --git a/components/net/lwip/port/lwipopts.h b/components/net/lwip/port/lwipopts.h
index 7d29d79b6b..52be6900cf 100644
--- a/components/net/lwip/port/lwipopts.h
+++ b/components/net/lwip/port/lwipopts.h
@@ -82,7 +82,11 @@
 #define LWIP_DNS                    0
 #endif
 
+#ifdef RT_LWIP_USING_LOOPBACK
+#define LWIP_HAVE_LOOPIF            1
+#else
 #define LWIP_HAVE_LOOPIF            0
+#endif
 
 #define LWIP_PLATFORM_BYTESWAP      0
 
@@ -541,7 +545,12 @@
 #define LWIP_RAW                    0
 #endif
 
+/* A loopback ping queues the request before lwIP generates its reply. */
+#ifdef RT_LWIP_NETIF_LOOPBACK
+#define DEFAULT_RAW_RECVMBOX_SIZE   2
+#else
 #define DEFAULT_RAW_RECVMBOX_SIZE   1
+#endif
 #define DEFAULT_ACCEPTMBOX_SIZE     10
 
 /* ---------- Statistics options ---------- */