feat(lwip): add fall back dns config in menuconfig

Closes https://github.com/espressif/esp-idf/issues/12530

components/lwip/Kconfig

@@ -130,7 +130,8 @@ menu "LWIP"
         depends on LWIP_ND6
         help
             This option is used to set the the router flag for the NA packets.
-            When enabled, the router flag in NA packet will always set to 1, otherwise, never set router flag for NA packets.
+            When enabled, the router flag in NA packet will always set to 1,
+            otherwise, never set router flag for NA packets.
 
     config LWIP_MAX_SOCKETS
         int "Max number of open sockets"
@@ -717,11 +718,14 @@ menu "LWIP"
                 cause Wi-Fi/Ethernet fail to release RX buffer in time.
                 It is possible that all RX buffers for MAC layer are used by OOSEQ.
 
-                Control the number of out-of-order pbufs to ensure that the MAC layer has enough RX buffer to receive packets.
+                Control the number of out-of-order pbufs to ensure that the MAC layer has
+                enough RX buffer to receive packets.
 
-                In the Wi-Fi scenario, recommended OOSEQ PBUFS Range: 0 <= TCP_OOSEQ_MAX_PBUFS <= CONFIG_ESP_WIFI_DYNAMIC_RX_BUFFER_NUM/(MAX_TCP_NUMBER + 1)
+                In the Wi-Fi scenario, recommended OOSEQ PBUFS Range:
+                0 <= TCP_OOSEQ_MAX_PBUFS <= CONFIG_ESP_WIFI_DYNAMIC_RX_BUFFER_NUM/(MAX_TCP_NUMBER + 1)
 
-                In the Ethernet scenario,recommended Ethernet OOSEQ PBUFS Range: 0 <= TCP_OOSEQ_MAX_PBUFS <= CONFIG_ETH_DMA_RX_BUFFER_NUM/(MAX_TCP_NUMBER + 1)
+                In the Ethernet scenario,recommended Ethernet OOSEQ PBUFS Range:
+                0 <= TCP_OOSEQ_MAX_PBUFS <= CONFIG_ETH_DMA_RX_BUFFER_NUM/(MAX_TCP_NUMBER + 1)
 
                 Within the recommended value range, the larger the value, the better the performance.
 
@@ -1058,6 +1062,33 @@ menu "LWIP"
 
     endmenu # SNTP
 
+    menu "DNS"
+
+        config LWIP_DNS_MAX_SERVERS
+            int "Maximum number of DNS servers"
+            default 3
+            range 1 4
+            help
+                Set maximum number of DNS servers.
+                If fallback DNS servers are supported,
+                the number of DNS servers needs to be greater than or equal to 3.
+
+        config LWIP_FALLBACK_DNS_SERVER_SUPPORT
+            bool "Enable DNS fallback server support"
+            default n
+            depends on LWIP_DNS_MAX_SERVERS >= 3
+            help
+                Enable this feature to support DNS fallback server.
+
+        config LWIP_FALLBACK_DNS_SERVER_ADDRESS
+            string "DNS fallback server address"
+            default "114.114.114.114"
+            depends on LWIP_FALLBACK_DNS_SERVER_SUPPORT
+            help
+                This option allows you to config dns fallback server address.
+
+    endmenu # DNS
+
     config LWIP_BRIDGEIF_MAX_PORTS
         int "Maximum number of bridge ports"
         default 7

components/lwip/lwip

@@ -1 +1 @@
-Subproject commit f5c43549e5d12ec2105a43c27986416124143e6e
+Subproject commit f79221431fa9042b3572d271d687de66da7560c4

components/lwip/port/include/lwipopts.h

@@ -3,7 +3,7 @@
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
- * SPDX-FileContributor: 2015-2023 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileContributor: 2015-2024 Espressif Systems (Shanghai) CO LTD
  */
 #ifndef LWIP_HDR_ESP_LWIPOPTS_H
 #define LWIP_HDR_ESP_LWIPOPTS_H
@@ -472,7 +472,7 @@ static inline uint32_t timeout_from_offered(uint32_t lease, uint32_t min)
 
 /** The maximum of DNS servers
  */
-#define DNS_MAX_SERVERS                 3
+#define DNS_MAX_SERVERS                 CONFIG_LWIP_DNS_MAX_SERVERS
 
 /** ESP specific option only applicable if ESP_DNS=1
  *
@@ -481,6 +481,14 @@ static inline uint32_t timeout_from_offered(uint32_t lease, uint32_t min)
  */
 #define DNS_FALLBACK_SERVER_INDEX       (DNS_MAX_SERVERS - 1)
 
+#ifdef CONFIG_LWIP_FALLBACK_DNS_SERVER_SUPPORT
+#define FALLBACK_DNS_SERVER_ADDRESS(address)                           \
+        do {    ip_addr_t *server_dns = address;                            \
+                char server_ip[] = CONFIG_LWIP_FALLBACK_DNS_SERVER_ADDRESS; \
+                ipaddr_aton(server_ip, server_dns);                         \
+        } while (0)
+#endif /* CONFIG_LWIP_FALLBACK_DNS_SERVER_SUPPORT */
+
 /**
  * LWIP_DNS_SUPPORT_MDNS_QUERIES==1: Enable mDNS queries in hostname resolution.
  * This option is set via menuconfig.
@@ -1576,6 +1584,7 @@ static inline uint32_t timeout_from_offered(uint32_t lease, uint32_t min)
 #define ESP_LWIP_LOCK                   1
 #define ESP_THREAD_PROTECTION           1
 #define LWIP_SUPPORT_CUSTOM_PBUF        1
+#define ESP_LWIP_FALLBACK_DNS_PREFER_IPV4 0
 
 /*
    -----------------------------------------