lwip: Enable IPv6 stateless address autoconfiguration

src/core/ipv4/ip4.c

@@ -1053,7 +1053,7 @@ ip4_output_if_opt_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *d
     return ip4_frag(p, netif, dest);
   }
 #else
-      LWIP_ERROR("ip4_output_if: Packets larger than MTU, discarded!!!",!(netif->mtu && p->tot_len > netif->mtu),return ERR_IF;);
+  LWIP_ERROR("ip4_output_if: Packets larger than MTU, discarded!!!",!(netif->mtu && p->tot_len > netif->mtu),return ERR_IF;);
 #endif /* IP_FRAG */
 
   LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: call netif->output()\n"));

src/core/netif.c

@@ -331,8 +331,12 @@ netif_add(struct netif *netif,
 #endif /* LWIP_NUM_NETIF_CLIENT_DATA */
 #if LWIP_IPV6
 #if LWIP_IPV6_AUTOCONFIG
+#if ESP_IPV6_AUTOCONFIG
+  netif->ip6_autoconfig_enabled = 1;
+#else
   /* IPv6 address autoconfiguration not enabled by default */
   netif->ip6_autoconfig_enabled = 0;
+#endif
 #endif /* LWIP_IPV6_AUTOCONFIG */
   nd6_restart_netif(netif);
 #endif /* LWIP_IPV6 */

src/include/lwip/opt.h

@@ -1010,6 +1010,13 @@
 #define LWIP_DHCP_AUTOIP_COOP           0
 #endif
 
+/**
+ * ESP_IPV6_AUTOCONFIG==1: Enable stateless address autoconfiguration as per RFC 4862.
+ */
+#if !defined ESP_IPV6_AUTOCONFIG
+#define ESP_IPV6_AUTOCONFIG 0
+#endif
+
 /**
  * LWIP_DHCP_AUTOIP_COOP_TRIES: Set to the number of DHCP DISCOVER probes
  * that should be sent before falling back on AUTOIP (the DHCP client keeps