broadcast.c

使用udp的broadcast方式写的c程序

#include <string.h> 
#include <sys/types.h> 
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <stdlib.h>
 
#include <sys/ioctl.h> 
#include <net/if.h> 
#include <net/if_arp.h> 
#include <net/ethernet.h> 
#include <signal.h> 
#include <netinet/ip.h> 

#include "broadcast.h"

int main(void)
{    
	int socket_descriptor, countsend,i=0;  
	struct sockaddr_in address; 
	broadcasttype *broadmsg;
	nettype *getmsg;
	
	int forkfd;
	forkfd=fork();
	if (forkfd>0) {
	
	broadmsg = (broadcasttype *)malloc(sizeof(broadcasttype)) ;
	bzero(broadmsg, sizeof(broadcasttype));

	socket_descriptor = socket(AF_INET, SOCK_DGRAM, 0);  
	if (socket_descriptor == -1) {      
		perror("Opening socket"); 
		exit(EXIT_FAILURE);
	}
	
	memset(&address, 0, sizeof(address)); 
	address.sin_port = htons(BROADCAST_PORT);    
	address.sin_family = AF_INET;
	address.sin_addr.s_addr = inet_addr(HOST_NAME);
	
	/*get broadcast message*/
	broadmsg = setbroadmsg();
	
	while(1) {
		countsend = sendto(socket_descriptor, broadmsg, sizeof(broadcasttype), 0,\
			(struct sockaddr *)&address, sizeof(address));
		if(countsend < 0) {  
			perror("sendto");
			exit(EXIT_FAILURE); 
		}
	//printf("Msg=%s\n", broadmsg->message);
	//printf("IPadr=%s\n", broadmsg->ipaddress);
	
	sleep(2);  
	} 
	free(broadmsg);
	exit(EXIT_SUCCESS);
	
	}/*end of fork()*/
	
	/*child process, receive backloop data*/
	else {
		getmsg = (nettype *)malloc(sizeof(nettype));
		bzero(getmsg, sizeof(nettype));
		for(i=1;i<101;i++) {
			getmsg = upd_receive_ip();
			printf("receive: %d\n",i);
			printf("MAC:%02x:%02x:%02x:%02x:%02x:%02x\n",\
				getmsg->mac_value[0],getmsg->mac_value[1],\
				getmsg->mac_value[2],getmsg->mac_value[3],\
				getmsg->mac_value[4],getmsg->mac_value[5]);
			printf("NETMASK:%s\n",getmsg->netmask_value);
			printf("IP:%s\n",getmsg->ip_value);
			printf("NAME: %s\n", getmsg->message);
		}
		free(getmsg);
		exit(0);
	}
}