AsyncUDPMulticastServer.ino

/****************************************************************************************************************************
  AsyncUDPMulticastServer.ino

  AsyncUDP_RP2040W is a library for the RP2040W with CYW43439 WiFi

  Based on and modified from ESPAsyncUDP (https://github.com/me-no-dev/ESPAsyncUDP)
  Built by Khoi Hoang https://github.com/khoih-prog/AsyncUDP_RP2040W
 *****************************************************************************************************************************/

#if !( defined(ARDUINO_RASPBERRY_PI_PICO_W) )
  #error For RASPBERRY_PI_PICO_W only
#endif

#include <WiFi.h>

// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
#include <AsyncUDP_RP2040W.h>         // https://github.com/khoih-prog/AsyncUDP_RP2040W

char ssid[] = "your_ssid";            // your network SSID (name)
char pass[] = "12345678";             // your network password (use for WPA, or use as key for WEP), length must be 8+

AsyncUDP udp;

int status = WL_IDLE_STATUS;

#define BUF_SZ      32

char buf[BUF_SZ];

void parsePacket(AsyncUDPPacket packet)
{
  Serial.print("UDP Packet Type: ");
  Serial.print(packet.isBroadcast() ? "Broadcast" : packet.isMulticast() ? "Multicast" : "Unicast");
  Serial.print(", From: ");
  Serial.print(packet.remoteIP());
  Serial.print(":");
  Serial.print(packet.remotePort());
  Serial.print(", To: ");
  Serial.print(packet.localIP());
  Serial.print(":");
  Serial.print(packet.localPort());
  Serial.print(", Length: ");
  Serial.print(packet.length());
  Serial.print(", Data: ");
  Serial.write(packet.data(), packet.length());
  Serial.println();

  snprintf(buf, sizeof(buf) - 1, "Got %u bytes of data", packet.length());
  //reply to the client
  // size_t write(const uint8_t *data, size_t len);
  packet.write((uint8_t*) buf, strlen(buf));
}

void printWifiStatus()
{
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print your board's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("Local IP Address: ");
  Serial.println(ip);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("signal strength (RSSI):");
  Serial.print(rssi);
  Serial.println(" dBm");
}

void setup()
{
  Serial.begin(115200);

  while (!Serial && millis() < 5000);

  Serial.print("\nStart AsyncUDPMulticastServer on ");
  Serial.println(BOARD_NAME);
  Serial.println(ASYNC_UDP_RP2040W_VERSION);

  ///////////////////////////////////

  // check for the WiFi module:
  if (WiFi.status() == WL_NO_MODULE)
  {
    Serial.println("Communication with WiFi module failed!");

    // don't continue
    while (true);
  }

  Serial.print(F("Connecting to SSID: "));
  Serial.println(ssid);

  status = WiFi.begin(ssid, pass);

  delay(1000);

  // attempt to connect to WiFi network
  while ( status != WL_CONNECTED)
  {
    delay(500);

    // Connect to WPA/WPA2 network
    status = WiFi.status();
  }

  printWifiStatus();

  ///////////////////////////////////

  if (udp.listenMulticast(IPAddress(239, 1, 2, 3), 1234))
  {
    Serial.print("UDP Listening on IP: ");
    Serial.println(WiFi.localIP());

    udp.onPacket([](AsyncUDPPacket packet)
    {
      parsePacket(packet);
    });

    //Send multicast
    udp.print("Hello!");
  }
}

void loop()
{
  delay(1000);
  //Send multicast
  udp.print("Anyone here?");
}