[ESP32] Compilation fix when IPV4 is disabled.

config/esp32/components/chip/CMakeLists.txt

@@ -118,7 +118,11 @@ chip_gn_arg_append("chip_config_network_layer_ble"           "false")
 endif()
 
 if(CONFIG_DISABLE_IPV4)
-    chip_gn_arg_append("chip_inet_config_enable_ipv4"        "false")
+    if(NOT CONFIG_LWIP_IPV4)
+        chip_gn_arg_append("chip_inet_config_enable_ipv4"        "false")
+    else()
+	message(FATAL_ERROR "Please also disable config option CONFIG_LWIP_IPV4")
+    endif()
 endif()
 
 if(CONFIG_DISABLE_READ_CLIENT)

docs/guides/esp32/README.md

@@ -19,3 +19,4 @@ example on ESP32 series of SoCs
 -   [Generating and Using ESP Secure Cert Partition](secure_cert_partition.md)
 -   [BLE Settings](ble_settings.md)
 -   [Providers](providers.md)
+-   [Configuration Options](config_options.md)

docs/guides/esp32/config_options.md

@@ -0,0 +1,13 @@
+# Configuration options
+
+This file lists down few config options to be enabled in through menuconfig for
+specific scenarios.
+
+### Building with IPV4 Disabled
+
+Enable the options below through `idf.py menuconfig` and build the app.
+
+```
+CONFIG_DISABLE_IPV4=y
+CONFIG_LWIP_IPV4=n
+```

src/platform/ESP32/BUILD.gn

@@ -14,6 +14,7 @@
 
 import("//build_overrides/chip.gni")
 
+import("${chip_root}/src/inet/inet.gni")
 import("${chip_root}/src/platform/device.gni")
 
 assert(chip_device_platform == "esp32")
@@ -36,6 +37,7 @@ declare_args() {
 
 defines = [
   "CHIP_CONFIG_SOFTWARE_VERSION_NUMBER=${chip_config_software_version_number}",
+  "CHIP_DEVICE_CONFIG_ENABLE_IPV4=${chip_inet_config_enable_ipv4}",
 ]
 
 static_library("ESP32") {

src/platform/ESP32/ConnectivityManagerImpl_WiFi.cpp

@@ -999,6 +999,7 @@ void ConnectivityManagerImpl::UpdateInternetConnectivityState(void)
                 // If the station interface has been assigned an IPv4 address, and has
                 // an IPv4 gateway, then presume that the device has IPv4 Internet
                 // connectivity.
+#if CHIP_DEVICE_CONFIG_ENABLE_IPV4
                 if (!ip4_addr_isany_val(*netif_ip4_addr(netif)) && !ip4_addr_isany_val(*netif_ip4_gw(netif)))
                 {
                     haveIPv4Conn = true;
@@ -1013,6 +1014,7 @@ void ConnectivityManagerImpl::UpdateInternetConnectivityState(void)
                         IPAddress::FromString(addrStr, addr);
                     }
                 }
+#endif
 
                 // Search among the IPv6 addresses assigned to the interface for a Global Unicast
                 // address (2000::/3) that is in the valid state.  If such an address is found...