extender.ino

// NAPT example released to public domain

#if LWIP_FEATURES && !LWIP_IPV6

#define HAVE_NETDUMP 0

// Define your SSID and Pass to Connect and get the network from
#ifndef STASSID
#define STASSID "SSID to Connect"
#define STAPSK "Password for SSID"
#endif


//includeing needed libraries
#include <ESP8266WiFi.h>
#include <lwip/napt.h>
#include <lwip/dns.h>
#include <dhcpserver.h>

#define NAPT 1000
#define NAPT_PORT 10

#if HAVE_NETDUMP

#include <NetDump.h>

void dump(int netif_idx, const char *data, size_t len, int out, int success)
{
  (void)success;
  Serial.print(out ? F("out ") : F(" in "));
  Serial.printf("%d ", netif_idx);

  // optional filter example: if (netDump_is_ARP(data))
  {
    netDump(Serial, data, len);
    // netDumpHex(Serial, data, len);
  }
}
#endif

// Setup the Functionality
void setup()
{
  Serial.begin(115200);
  Serial.printf("\n\nNAPT Range extender\n");
  Serial.printf("Heap on start: %d\n", ESP.getFreeHeap());

#if HAVE_NETDUMP
  phy_capture = dump;
#endif

  // first, connect to STA so we can get a proper local DNS server
  WiFi.mode(WIFI_STA);
  WiFi.begin(STASSID, STAPSK);
  while (WiFi.status() != WL_CONNECTED)
  {
    Serial.print('.');
    delay(500);
  }
  Serial.printf("\nSTA: %s (dns: %s / %s)\n",
                WiFi.localIP().toString().c_str(),
                WiFi.dnsIP(0).toString().c_str(),
                WiFi.dnsIP(1).toString().c_str());

  // give DNS servers to AP side
  dhcps_set_dns(0, WiFi.dnsIP(0));
  dhcps_set_dns(1, WiFi.dnsIP(1));

  WiFi.softAPConfig( // enable AP, with android-compatible google domain
      IPAddress(172, 217, 28, 254),
      IPAddress(172, 217, 28, 254),
      IPAddress(255, 255, 255, 0));
  WiFi.softAP(STASSID "extender", STAPSK);
  Serial.printf("AP: %s\n", WiFi.softAPIP().toString().c_str());

  Serial.printf("Heap before: %d\n", ESP.getFreeHeap());
  err_t ret = ip_napt_init(NAPT, NAPT_PORT);
  Serial.printf("ip_napt_init(%d,%d): ret=%d (OK=%d)\n", NAPT, NAPT_PORT, (int)ret, (int)ERR_OK);
  if (ret == ERR_OK)
  {
    ret = ip_napt_enable_no(SOFTAP_IF, 1);
    Serial.printf("ip_napt_enable_no(SOFTAP_IF): ret=%d (OK=%d)\n", (int)ret, (int)ERR_OK);
    if (ret == ERR_OK)
    {
      Serial.printf("WiFi Network '%s' with same password is now NATed behind '%s'\n", STASSID "extender", STASSID);
    }
  }
  Serial.printf("Heap after napt init: %d\n", ESP.getFreeHeap());
  if (ret != ERR_OK)
  {
    Serial.printf("NAPT initialization failed\n");
  }
}

#else

void setup()
{
  Serial.begin(115200);
  Serial.printf("\n\nNAPT not supported in this configuration\n");
}

#endif

void loop()
{
}