feat(mdns): Add reverse lookup to the example and test

components/mdns/examples/main/mdns_example_main.c

@@ -276,16 +276,15 @@ void app_main(void)
      * This is typically performed in "GOT_IP" event handler, but we call it here directly
      * since the `EXAMPLE_INTERFACE` netif is connected already, to keep the example simple.
      */
-    ESP_ERROR_CHECK(mdns_netif_action(EXAMPLE_INTERFACE, MDNS_EVENT_ENABLE_IP4));
-    ESP_ERROR_CHECK(mdns_netif_action(EXAMPLE_INTERFACE, MDNS_EVENT_ANNOUNCE_IP4));
-#endif
+    ESP_ERROR_CHECK(mdns_netif_action(EXAMPLE_INTERFACE, MDNS_EVENT_ENABLE_IP4 | MDNS_EVENT_ENABLE_IP6));
+    ESP_ERROR_CHECK(mdns_netif_action(EXAMPLE_INTERFACE, MDNS_EVENT_ANNOUNCE_IP4 | MDNS_EVENT_ANNOUNCE_IP6));
 
 #if defined(CONFIG_MDNS_RESPOND_REVERSE_QUERIES)
-    while (mdns_netif_action(EXAMPLE_INTERFACE, MDNS_EVENT_IP4_REVERSE_LOOKUP) != ESP_OK) {
-        vTaskDelay(50 / portTICK_PERIOD_MS);
-    }
+    ESP_ERROR_CHECK(mdns_netif_action(EXAMPLE_INTERFACE, MDNS_EVENT_IP4_REVERSE_LOOKUP | MDNS_EVENT_IP6_REVERSE_LOOKUP));
 #endif
 
+#endif // CONFIG_MDNS_ADD_CUSTOM_NETIF
+
     initialise_button();
     xTaskCreate(&mdns_example_task, "mdns_example_task", 2048, NULL, 5, NULL);
 }

components/mdns/examples/pytest_mdns.py

@@ -120,10 +120,11 @@ def test_examples_protocol_mdns(dut):
       2. get the dut host name (and IP address)
       3. check the mdns name is accessible
       4. check DUT output if mdns advertized host is resolved
+      5. check if DUT responds to dig
+      6. check the DUT is searchable via reverse IP lookup
     """
 
-    specific_host = dut.expect(re.compile(
-        b'mdns hostname set to: \[(.*?)\]')).group(1).decode()  # noqa: W605
+    specific_host = dut.expect(r'mdns hostname set to: \[(.*?)\]')[1].decode()
 
     mdns_server_events = {
         'stop': Event(),
@@ -132,9 +133,14 @@ def test_examples_protocol_mdns(dut):
     }
     mdns_responder = Thread(target=mdns_server,
                             args=(str(specific_host), mdns_server_events))
-    ip_address = dut.expect(
-        re.compile(b'IPv4 address:([a-zA-Z0-9]*).*')).group(1).decode()
-    print('Connected to AP with IP: {}'.format(ip_address))
+    ipv4 = dut.expect(r'IPv4 address: (\d+\.\d+\.\d+\.\d+)[^\d]',
+                      timeout=30)[1].decode()
+    ip_addresses = [ipv4]
+    if dut.app.sdkconfig.get('LWIP_IPV6') is True:
+        ipv6_r = r':'.join((r'[0-9a-fA-F]{4}', ) * 8)
+        ipv6 = dut.expect(ipv6_r, timeout=30)[0].decode()
+        ip_addresses.append(ipv6)
+    print('Connected with IP addresses: {}'.format(','.join(ip_addresses)))
     try:
         # 3. check the mdns name is accessible.
         mdns_responder.start()
@@ -165,11 +171,25 @@ def test_examples_protocol_mdns(dut):
         ])
         print('Resolving {} using "dig" succeeded with:\n{}'.format(
             specific_host, dig_output))
-        if not ip_address.encode('utf-8') in dig_output:
+        if not ipv4.encode('utf-8') in dig_output:
             raise ValueError(
                 'Test has failed: Incorrectly resolved DUT hostname using dig'
-                "Output should've contained DUT's IP address:{}".format(
-                    ip_address))
+                "Output should've contained DUT's IP address:{}".format(ipv4))
+        # 6. check the DUT reverse lookup
+        if dut.app.sdkconfig.get('MDNS_RESPOND_REVERSE_QUERIES') is True:
+            for ip_address in ip_addresses:
+                dig_output = subprocess.check_output([
+                    'dig', '+short', '-p', '5353', '@224.0.0.251', '-x',
+                    '{}'.format(ip_address)
+                ])
+                print('Reverse lookup for {} using "dig" succeeded with:\n{}'.
+                      format(ip_address, dig_output))
+                if specific_host not in dig_output.decode():
+                    raise ValueError(
+                        'Test has failed: Incorrectly resolved DUT IP address using dig'
+                        "Output should've contained DUT's name:{}".format(
+                            specific_host))
+
     finally:
         mdns_server_events['stop'].set()
         mdns_responder.join()

components/mdns/examples/sdkconfig.ci.eth_custom_netif

@@ -6,6 +6,7 @@ CONFIG_MDNS_PREDEF_NETIF_STA=n
 CONFIG_MDNS_PREDEF_NETIF_AP=n
 CONFIG_MDNS_PREDEF_NETIF_ETH=n
 CONFIG_MDNS_ADD_CUSTOM_NETIF=y
+CONFIG_MDNS_RESPOND_REVERSE_QUERIES=y
 CONFIG_LWIP_DNS_SUPPORT_MDNS_QUERIES=y
 CONFIG_EXAMPLE_CONNECT_ETHERNET=y
 CONFIG_EXAMPLE_CONNECT_WIFI=n

components/mdns/mdns.c

@@ -4016,6 +4016,7 @@ static void perform_event_action(mdns_if_t mdns_if, mdns_event_actions_t action)
         }
     }
 
+#ifdef CONFIG_LWIP_IPV6
     if (action & MDNS_EVENT_IP6_REVERSE_LOOKUP) {
         esp_ip6_addr_t addr6;
         if (!esp_netif_get_ip6_linklocal(_mdns_get_esp_netif(mdns_if), &addr6) && !_ipv6_address_is_zero(addr6)) {
@@ -4039,7 +4040,7 @@ static void perform_event_action(mdns_if_t mdns_if, mdns_event_actions_t action)
             }
         }
     }
-
+#endif /* CONFIG_LWIP_IPV6 */
 #endif /* CONFIG_MDNS_RESPOND_REVERSE_QUERIES */
 }