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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#ifdef _WIN32
#include <winsock2.h>
#include <ws2tcpip.h>
//#pragma does not work on mingw
//#pragma comment(lib, "Ws2_32.lib")
#else
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#endif
#define MCAST_PORT 4532
#define MCAST_ADDR "224.0.0.1"
#define BUFFER_SIZE 4096
int main()
{
int sock;
struct sockaddr_in mcast_addr;
char buffer[BUFFER_SIZE];
int bytes_received;
#ifdef _WIN32
WSADATA wsaData;
if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
{
fprintf(stderr, "WSAStartup failed: %d\n", WSAGetLastError());
return 1;
}
#endif
if ((sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
{
perror("socket() failed");
exit(EXIT_FAILURE);
}
// Set the SO_REUSEADDR option to allow multiple processes to use the same address
int optval = 1;
if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&optval,
sizeof(optval)) < 0)
{
//rig_debug(RIG_DEBUG_ERR, "%s: setsockopt: %s\n", __func__, strerror(errno));
//return -RIG_EIO;
return 1;
}
memset(&mcast_addr, 0, sizeof(mcast_addr));
mcast_addr.sin_family = AF_INET;
mcast_addr.sin_port = htons(MCAST_PORT);
mcast_addr.sin_addr.s_addr = htonl(INADDR_ANY);
if (bind(sock, (struct sockaddr *)&mcast_addr, sizeof(mcast_addr)) < 0)
{
perror("bind() failed");
exit(EXIT_FAILURE);
}
struct ip_mreq mreq;
mreq.imr_multiaddr.s_addr = inet_addr(MCAST_ADDR);
mreq.imr_interface.s_addr = htonl(INADDR_ANY);
if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&mreq,
sizeof(mreq)) < 0)
{
perror("setsockopt() failed");
exit(EXIT_FAILURE);
}
while (1)
{
bytes_received = recvfrom(sock, buffer, BUFFER_SIZE, 0, NULL, 0);
if (bytes_received < 0)
{
perror("recvfrom() failed");
break;
}
buffer[bytes_received] = '\0';
printf("%s\n", buffer);
}
// Drop membership before closing the socket
if (setsockopt(sock, IPPROTO_IP, IP_DROP_MEMBERSHIP, (char *)&mreq,
sizeof(mreq)) < 0)
{
perror("setsockopt() failed");
}
close(sock);
#ifdef _WIN32
WSACleanup();
#endif
return 0;
}
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