Merge branch 'optimization/get_dns_server_and_add_dns_enable_ipv6_dns_retrieval' into 'release/v3.3'

lw-ip:optimization get dns server and add dns enable ipv6 dns retrieval

See merge request espressif/esp-idf!7643

components/lwip/lwip

@@ -1 +1 @@
-Subproject commit 057f7f6a8ca3cd736009cc80d4f429f42b0db254
+Subproject commit da2740fa8d56b9b9e8a10602f38df1ea4dbd9b74

components/lwip/port/esp32/include/lwipopts.h

@@ -660,6 +660,13 @@
  */
 #define LWIP_IPV6                       1
 
+/**
+ * LWIP_ND6_RDNSS_MAX_DNS_SERVERS: Allow IPv6 DNS servers to be retrieved from
+ * NDP, up to the maximum number of allowed DNS servers (minus fallback slot)
+ */
+#define LWIP_ND6_RDNSS_MAX_DNS_SERVERS  DNS_MAX_SERVERS
+
+
 /*
    ---------------------------------------
    ---------- Hook options ---------------

components/tcpip_adapter/tcpip_adapter_lwip.c

@@ -775,6 +775,7 @@ esp_err_t tcpip_adapter_get_dns_info(tcpip_adapter_if_t tcpip_if, tcpip_adapter_
 
     dns_param.dns_type =  type;
     dns_param.dns_info =  dns;
+    const ip_addr_t*  dns_ip = NULL;
     
     TCPIP_ADAPTER_IPC_CALL(tcpip_if, type,  0, &dns_param, tcpip_adapter_get_dns_info_api);
     if (!dns) {
@@ -793,7 +794,10 @@ esp_err_t tcpip_adapter_get_dns_info(tcpip_adapter_if_t tcpip_if, tcpip_adapter_
     }
 
     if (tcpip_if == TCPIP_ADAPTER_IF_STA || tcpip_if == TCPIP_ADAPTER_IF_ETH) {
-        dns->ip = dns_getserver(type);
+        dns_ip = dns_getserver(type);
+        if (dns_ip != NULL) {
+            dns->ip = *dns_ip;
+        }
     } else {
         dns->ip.u_addr.ip4 = dhcps_dns_getserver();
     }

examples/protocols/pppos_client/components/modem/src/esp_modem.c

@@ -454,6 +454,7 @@ esp_err_t esp_modem_remove_event_handler(modem_dte_t *dte, esp_event_handler_t h
 static void on_ppp_status_changed(ppp_pcb *pcb, int err_code, void *ctx)
 {
     struct netif *pppif = ppp_netif(pcb);
+    const ip_addr_t *dest_ip = NULL;
     modem_dte_t *dte = (modem_dte_t *)(ctx);
     esp_modem_dte_t *esp_dte = __containerof(dte, esp_modem_dte_t, parent);
     ppp_client_ip_info_t ipinfo = {0};
@@ -462,8 +463,15 @@ static void on_ppp_status_changed(ppp_pcb *pcb, int err_code, void *ctx)
         ipinfo.ip = pppif->ip_addr.u_addr.ip4;
         ipinfo.gw = pppif->gw.u_addr.ip4;
         ipinfo.netmask = pppif->netmask.u_addr.ip4;
-        ipinfo.ns1 = dns_getserver(0).u_addr.ip4;
-        ipinfo.ns2 = dns_getserver(1).u_addr.ip4;
+        dest_ip = dns_getserver(0);
+        if(dest_ip != NULL) {
+          ipinfo.ns1 = dest_ip->u_addr.ip4;
+        }
+        dest_ip = dns_getserver(1);
+        if(dest_ip != NULL) {
+          ipinfo.ns2 = dest_ip->u_addr.ip4;
+        }
+
         esp_event_post_to(esp_dte->event_loop_hdl, ESP_MODEM_EVENT, MODEM_EVENT_PPP_CONNECT, &ipinfo, sizeof(ipinfo), 0);
         break;
     case PPPERR_PARAM: