学步园

服务器端代码：

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <memory.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>


#define MCAST_PORT 31241
#define LOCAL_PORT 56171
#define MCAST_ADDR "224.1.2.3"
#define LocalIPAddr "10.10.106.108"
#define MCAST_DATA "111111222223333344444"
unsigned char buffer[]={"111111222223333344444"};     // UDP packet limit size: 15000 bytes 

 main(int argc, char **argv)
{
	int soketfd;  //sn?
	int err;
	int n =0;
	int count = 0;
	int temp =0x11;
	int ttl =150;
	struct sockaddr_in mcast_addr;
  struct sockaddr_in local_addr;         // Sender socket address structure
	struct ip_mreq host_madd_ifadd;		//struct init instance	

	soketfd=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
	//soketfd=socket(AF_INET,SOCK_RAW,IPPROTO_UDP);
	if(soketfd == -1 )
	{
		perror("socket()");
		return -1;
	}
	
	bzero(&local_addr, sizeof(struct sockaddr_in) );
	bzero(&mcast_addr, sizeof(struct sockaddr_in) );
	mcast_addr.sin_family =AF_INET;
	mcast_addr.sin_port=htons(MCAST_PORT);
	mcast_addr.sin_addr.s_addr =inet_addr(MCAST_ADDR);
	local_addr.sin_family = AF_INET;
	local_addr.sin_port = htons(LOCAL_PORT); 

	if(argv[1]!= NULL ) 
	{	
		if(inet_pton(AF_INET, argv[1], &local_addr.sin_addr.s_addr) <= 0) 
		{
			printf("set ip address error!\n");
			exit(0);
		}
	}
	else
	{
			printf("please give a local address ip !\n");
			exit(0);
	}	

 /* if(argv[2]!= NULL ) 
	{
			local_addr.sin_port = htons(atoi(argv[2]));		
			mcast_addr.sin_port=	htons(atoi(argv[2]));
			printf("port:%d\n",atoi(argv[2]));
		
	}
	else
	{
		local_addr.sin_port = htons(LOCAL_PORT); 
		mcast_addr.sin_port=htons(MCAST_PORT);
	}*/
	
 // local_addr.sin_addr.s_addr =inet_addr(LocalIPAddr);
	   		
	if(bind(soketfd,(struct sockaddr *)&local_addr, sizeof(local_addr) ) < 0 )
	{
		printf("bind() error \n");
	
	}

  setsockopt(soketfd,IPPROTO_IP,IP_MULTICAST_TTL,&ttl,sizeof(ttl)); 
//	strcpy(buffer,MCAST_DATA);
	
	while(1)
	{
		n=sendto(soketfd,buffer,sizeof(buffer),0,(struct sockaddr *)&mcast_addr,sizeof(mcast_addr));
		if(n<0)
		{
			perror("sendto()");
			return -2;
		}
		usleep(2);
	}
}

客户端代码：

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <memory.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>


#define MCAST_PORT 31241
#define MCAST_ADDR "224.1.2.3"
#define LocalIPAddr "192.168.197.125"
unsigned char buffer[5000];     // UDP packet limit size: 1500 bytes 
 main(int argc, char **argv)
{
	int soketfd;  //sn?
	int err;
	int revLen =0;
	int counter =0;
	struct sockaddr_in brcast_source_addr;
	struct sockaddr_in source_addr;
	struct ip_mreq host_madd_ifadd;		//struct init instance	
	int forwardSocketFd;  //sn?
	int len = sizeof(struct sockaddr_in);
	
	fd_set rfds;
	struct timeval tv;
	int retval;
	soketfd=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
	if(soketfd == -1)
	{
		perror("socket()");
		return -1;
	}

	//memset(&mcast_addr,0,sizeof(mcast_addr));
	bzero(&brcast_source_addr, sizeof(struct sockaddr_in) );
	brcast_source_addr.sin_family =AF_INET;
	brcast_source_addr.sin_addr.s_addr =inet_addr(MCAST_ADDR);
	brcast_source_addr.sin_port=htons(MCAST_PORT);
	
	host_madd_ifadd.imr_multiaddr.s_addr=inet_addr(MCAST_ADDR);
//	host_madd_ifadd.imr_interface.s_addr=inet_addr(LocalIPAddr);
	
 // host_madd_ifadd.imr_interface.s_addr= htons(INADDR_ANY); 
	if(argv[1]!= NULL ) 
	{	
		if(inet_pton(AF_INET, argv[1], &host_madd_ifadd.imr_interface.s_addr) <= 0) 
		{
			printf("set ip address error!\n");
			exit(0);
		}
	}
	else
	{
			printf("please give a local address ip !\n");
			exit(0);
	}
		
	if(bind(soketfd,(struct sockaddr *)&brcast_source_addr, sizeof(brcast_source_addr)) < 0 )
	{
		printf("bind() soketfd error \n");
	
	}       
 	//sever host join into multicast.将本机加入组播组，足有加入组才能接受到消息。
	err=setsockopt(soketfd, IPPROTO_IP, IP_ADD_MEMBERSHIP,(void *)&host_madd_ifadd, sizeof( host_madd_ifadd ));
	if(err<0)
	{
		printf("ERR:2_setsockopt():IP_ADD_MEMBERSHIP %d\r\n",err);
	}
	else
	{
			printf(" host join  group 224.1.2.3 ok............\n");
	}

	while(1)
	{	
		#if 1
       //	printf("------------------------------------\n");
				revLen=recvfrom(soketfd,buffer,sizeof(buffer),0,(struct sockaddr *)&source_addr,(socklen_t*)&len);
				if(revLen<0)
				{
					perror("recvfrom()");
					return -2;
				}
				
				else
				{
				 		printf("revLen :%d brocast_srouce:%s\t brocast_port:%d\t counter:%d\n",revLen,inet_ntoa(source_addr.sin_addr),ntohs(source_addr.sin_port),counter++);			
				}
				
		#endif 
		usleep(1);
	}

}