test_igmp_Snd = udp_new();

err = udp_bind(test_igmp_Snd, IP_ADDR_ANY, TEST_IGMP_SERVER_PORT);

udp_recv(test_igmp_Snd, test_igmp_recCallback, NULL);

test_igmp_recCallback(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)

err_t  sendIGMP(struct udp_pcb *upcb, struct ip4_addr *addr, u16_t port, uint8_t *data, uint16_t data_length)

#include "UDPSocket.h"
#include "math.h"
#include "arm_math.h" 
#define ECHO_SERVER_PORT   8000
#define SERVER_ADDR "192.168.31.30"
static const char*          mbedIp       = "192.168.31.106";  //IP
static const char*          mbedMask     = "255.255.255.0";  // Mask
static const char*          mbedGateway  = "192.168.31.1";    //Gateway
int main (void) {
    
    EthernetInterface eth;
    eth.set_network(mbedIp,mbedMask,mbedGateway);
    eth.connect();
    printf("\nServer IP Address is %s\n", eth.get_ip_address());
    
    UDPSocket server;
    server.open(&eth);
    server.bind(