[tcp] multicast reciever

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#define MULTICAST_ADDR "239.0.0.1"

#define PORT 8888

#define BUFSIZE 1024

int main(int argc, char** argv) {

int sock;

struct sockaddr_in addr;

char buf[BUFSIZE];

int recv_len;

struct ip_mreq mreq;

int enable = 1;

// 멀티캐스트 소켓 생성

sock = socket(AF_INET, SOCK_DGRAM, 0);

if (sock < 0) {

perror("Failed to create socket");

exit(EXIT_FAILURE);

}

// 멀티캐스트 TTL 설정

setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL, &enable, sizeof(enable));

// 멀티캐스트 그룹에 참여

mreq.imr_multiaddr.s_addr = inet_addr(MULTICAST_ADDR);

mreq.imr_interface.s_addr = htonl(INADDR_ANY);

setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq));

// 소켓 주소 설정

memset(&addr, 0, sizeof(addr));

addr.sin_family = AF_INET;

addr.sin_addr.s_addr = htonl(INADDR_ANY);

addr.sin_port = htons(PORT);

// 소켓 바인드

if (bind(sock, (struct sockaddr*)&addr, sizeof(addr)) < 0) {

perror("Failed to bind socket");

exit(EXIT_FAILURE);

}

// 데이터 수신 및 출력

while (1) {

memset(buf, 0, BUFSIZE);

recv_len = recv(sock, buf, BUFSIZE, 0);

if (recv_len < 0) {

perror("Failed to receive data");

exit(EXIT_FAILURE);

}

printf("Received data: %s\n", buf);

}

// 소켓 닫기

close(sock);

return 0;

}