UdpSendReceive.ino

/****************************************************************************************************************************
  UDPSendReceive.ino - Simple Arduino web server sample for ESP8266/ESP32 AT-command shield
  For STM32F/L/H/G/WB/MP1 with built-in Ethernet LAN8742A (Nucleo-144, DISCOVERY, etc) or W5x00/ENC28J60 shield/module

  EthernetWebServer_SSL_STM32 is a library for STM32 using the Ethernet shields to run WebServer and Client with/without SSL

  Use SSLClient Library code from https://github.com/OPEnSLab-OSU/SSLClient

  Built by Khoi Hoang https://github.com/khoih-prog/EthernetWebServer_SSL_STM32
 *****************************************************************************************************************************/

#include "defines.h"

unsigned int localPort = 1883;    //10002;  // local port to listen on

char packetBuffer[255];          // buffer to hold incoming packet
char ReplyBuffer[] = "ACK";      // a string to send back

// A UDP instance to let us send and receive packets over UDP
EthernetUDP Udp;

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

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

  Serial.println("\nStart UDPSendReceive on " + String(BOARD_NAME) + " with " + String(SHIELD_TYPE));

#if USE_ETHERNET_GENERIC
  Serial.println(ETHERNET_GENERIC_VERSION);
#endif

  Serial.println(ETHERNET_WEBSERVER_SSL_STM32_VERSION);

#if !(USE_BUILTIN_ETHERNET)
#if (USING_SPI2)
#if defined(CUR_PIN_MISO)
  ET_LOGWARN(F("Default SPI pinout:"));
  ET_LOGWARN1(F("MOSI:"), CUR_PIN_MOSI);
  ET_LOGWARN1(F("MISO:"), CUR_PIN_MISO);
  ET_LOGWARN1(F("SCK:"),  CUR_PIN_SCK);
  ET_LOGWARN1(F("SS:"),   CUR_PIN_SS);
  ET_LOGWARN(F("========================="));
#endif
#else
  ET_LOGWARN(F("Default SPI pinout:"));
  ET_LOGWARN1(F("MOSI:"), MOSI);
  ET_LOGWARN1(F("MISO:"), MISO);
  ET_LOGWARN1(F("SCK:"),  SCK);
  ET_LOGWARN1(F("SS:"),   SS);
  ET_LOGWARN(F("========================="));
#endif
#endif

#if !(USE_BUILTIN_ETHERNET || USE_UIP_ETHERNET)
  // For other boards, to change if necessary
#if ( USE_ETHERNET_GENERIC || USE_ETHERNET_ENC )
  Ethernet.init (USE_THIS_SS_PIN);

#elif USE_CUSTOM_ETHERNET
  // You have to add initialization for your Custom Ethernet here
  // This is just an example to setCSPin to USE_THIS_SS_PIN, and can be not correct and enough
  //Ethernet.init(USE_THIS_SS_PIN);

#endif  //( ( USE_ETHERNET_GENERIC || USE_ETHERNET_ENC )
#endif

  // start the ethernet connection and the server:
  // Use DHCP dynamic IP and random mac
  uint16_t index = millis() % NUMBER_OF_MAC;
  // Use Static IP
  //Ethernet.begin(mac[index], ip);
  Ethernet.begin(mac[index]);

  Serial.print(F("Connected! IP address: "));
  Serial.println(Ethernet.localIP());

  Serial.println(F("\nStarting connection to server..."));
  // if you get a connection, report back via serial:
  Udp.begin(localPort);

  Serial.print(F("Listening on port "));
  Serial.println(localPort);
}

void loop()
{
  // if there's data available, read a packet
  int packetSize = Udp.parsePacket();

  if (packetSize)
  {
    Serial.print(F("Received packet of size "));
    Serial.println(packetSize);
    Serial.print(F("From "));
    IPAddress remoteIp = Udp.remoteIP();
    Serial.print(remoteIp);
    Serial.print(F(", port "));
    Serial.println(Udp.remotePort());

    // read the packet into packetBufffer
    int len = Udp.read(packetBuffer, 255);

    if (len > 0)
    {
      packetBuffer[len] = 0;
    }

    Serial.println(F("Contents:"));
    Serial.println(packetBuffer);

    // send a reply, to the IP address and port that sent us the packet we received
    Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
    Udp.write(ReplyBuffer);
    Udp.endPacket();
  }
}