news_sender_brd.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUF_SIZE 30
void error_handling(char *buf)
{
	fputs(buf, stderr);
	fputc('\n',stderr);
	exit(1);
}

int main(int argc, char const *argv[])
{
	int send_sock;
	struct sockaddr_in broad_adr;
	FILE *fp;
	char buf[BUF_SIZE];
	int so_brd = 1;
	if (argc != 3)
	{
		printf("Usage : %s <GroupIP> <port>\n", argv[0]);
		exit(1);
	}
	send_sock = socket(PF_INET, SOCK_DGRAM, 0);
	memset(&broad_adr, 0, sizeof(broad_adr));
	broad_adr.sin_family = AF_INET;
	if(!inet_aton(argv[1], &broad_adr.sin_addr))
		error_handling("convertion error");      // multicast IP
	broad_adr.sin_port = htons(atoi(argv[2]));     //multicast Port

	setsockopt(send_sock, SOL_SOCKET, SO_BROADCAST, (void*)&so_brd, sizeof(so_brd));
	if((fp = fopen("news.txt","r")) == NULL)
		error_handling("open file error");

	while(!feof(fp))
	{
		fgets(buf, BUF_SIZE, fp);
		sendto(send_sock, buf, strlen(buf), 0, (struct sockaddr*)&broad_adr, sizeof(broad_adr));
		sleep(2);
	}
	fclose(fp);
	close(send_sock);

	return 0;
}