feat(lwip): Add support for disabling IPv4 in PPP networks

components/esp_netif/lwip/esp_netif_lwip_ppp.c

@@ -231,7 +231,9 @@ netif_related_data_t * esp_netif_new_ppp(esp_netif_t *esp_netif, const esp_netif
 #if PPP_NOTIFY_PHASE
     ppp_set_notify_phase_callback(ppp_obj->ppp, on_ppp_notify_phase);
 #endif
+#if PPP_IPV4_SUPPORT
     ppp_set_usepeerdns(ppp_obj->ppp, 1);
+#endif
 
     return (netif_related_data_t *)ppp_obj;
 }

components/lwip/Kconfig

@@ -882,24 +882,6 @@ menu "LWIP"
         default 0x0 if LWIP_TCPIP_TASK_AFFINITY_CPU0
         default 0x1 if LWIP_TCPIP_TASK_AFFINITY_CPU1
 
-
-    menuconfig LWIP_PPP_SUPPORT
-        bool "Enable PPP support"
-        default n
-        help
-            Enable PPP stack. Now only PPP over serial is possible.
-
-    config LWIP_PPP_ENABLE_IPV6
-        bool "Enable IPV6 support for PPP connections (IPV6CP)"
-        depends on LWIP_PPP_SUPPORT && LWIP_IPV6
-        default y
-        help
-            Enable IPV6 support in PPP for the local link between the DTE (processor) and DCE (modem).
-            There are some modems which do not support the IPV6 addressing in the local link.
-            If they are requested for IPV6CP negotiation, they may time out.
-            This would in turn fail the configuration for the whole link.
-            If your modem is not responding correctly to PPP Phase Network, try to disable IPV6 support.
-
     config LWIP_IPV6_MEMP_NUM_ND6_QUEUE
         int "Max number of IPv6 packets to queue during MAC resolution"
         depends on LWIP_IPV6
@@ -916,6 +898,32 @@ menu "LWIP"
         help
             Config max number of entries in IPv6 neighbor cache
 
+    menuconfig LWIP_PPP_SUPPORT
+        bool "Enable PPP support"
+        default n
+        help
+            Enable PPP stack. Now only PPP over serial is possible.
+
+    config LWIP_PPP_ENABLE_IPV4
+        bool "Enable IPV4 support for PPP connections (IPCP)"
+        depends on LWIP_PPP_SUPPORT && LWIP_IPV4
+        default y
+        help
+            Enable IPCP protocol in PPP negotiations, which assigns IPv4 addresses to the PPP client,
+            as well as IPv4 DNS servers.
+            You can disable this if your modem supports IPv6 only.
+
+    config LWIP_PPP_ENABLE_IPV6
+        bool "Enable IPV6 support for PPP connections (IPV6CP)"
+        depends on LWIP_PPP_SUPPORT && LWIP_IPV6
+        default y
+        help
+            Enable IPV6 support in PPP for the local link between the DTE (processor) and DCE (modem).
+            There are some modems which do not support the IPV6 addressing in the local link.
+            If they are requested for IPV6CP negotiation, they may time out.
+            This would in turn fail the configuration for the whole link.
+            If your modem is not responding correctly to PPP Phase Network, try to disable IPV6 support.
+
     config LWIP_PPP_NOTIFY_PHASE_SUPPORT
         bool "Enable Notify Phase Callback"
         depends on LWIP_PPP_SUPPORT

components/lwip/port/include/lwipopts.h

@@ -1080,6 +1080,11 @@ static inline uint32_t timeout_from_offered(uint32_t lease, uint32_t min)
  */
 #define PPP_IPV6_SUPPORT                               CONFIG_LWIP_PPP_ENABLE_IPV6
 
+/**
+ * PPP_IPV4_SUPPORT==1: Enable PPP IPv4 support
+ */
+#define PPP_IPV4_SUPPORT                               CONFIG_LWIP_PPP_ENABLE_IPV4
+
 /**
  * PPP_NOTIFY_PHASE==1: Support PPP notify phase.
  */