mc_svr.c

一个基于linux的TCP/IP协议栈的实现

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <arpa/inet.h>
#include "my_inet.h"

#define MAXBUF 256
#define PUERTO 5000
#define GROUP "224.0.1.1"
int main(void)
{
	int fd, mc_loop = 1, mc_ttl = 25;
	struct sockaddr_in srv,local;
	struct in_addr if_req;
	char buf[MAXBUF];

	srv.sin_family = MY_AF_INET;
	srv.sin_port = htons(PUERTO);
	inet_aton(GROUP, &srv.sin_addr);
	
	if( (fd = socket( MY_AF_INET, SOCK_DGRAM, MY_IPPROTO_UDP) ) < 0 ){
		perror("socket");
		return -1;
	}
	inet_aton("172.16.48.2", &(if_req) );
	if( setsockopt( fd, SOL_IP, IP_MULTICAST_IF, &if_req, sizeof(struct in_addr) ) < 0 ){
		perror("setsockopt:");
		return -1;
	}
	if( setsockopt( fd, SOL_IP, IP_MULTICAST_LOOP, &mc_loop, sizeof(int) ) < 0 ){
		perror("setsockopt:");
		return -1;
	}
	if( setsockopt( fd, SOL_IP, IP_MULTICAST_TTL, &mc_ttl, sizeof(int) ) < 0 ){
		perror("setsockopt:");
		return -1;
	}
	while( fgets(buf, MAXBUF, stdin) ){
		if( sendto(fd, buf, strlen(buf), 0, (struct sockaddr *)&srv, sizeof(srv)) < 0 ){
			perror("sendto");
		}else{
			fprintf(stdout, "Enviado a %s: %s", GROUP, buf);
		}
	}
}