UDP通信之单播、广播和多播

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<sys/socket.h>
 4 #include<netdb.h>
 5 #include<sys/types.h>
 6 #include<arpa/inet.h>
 7 #include<netinet/in.h>
 8 #include<unistd.h>
 9 #include<stdlib.h>
10 #include<string.h>
11 #define MCAST_PORT 8888
12 #define MCAST_ADDR "224.0.0.88"  // 多播地址
13 #define MCAST_DATA "BROADCAST TEST DATA"  // 多播内容
14 #define MCAST_INTERVAL 5  //多播时间间隔
15 using namespace std;
16 
17 int main()
18 {
19         int sock;
20         struct sockaddr_in mcast_addr;
21         sock=socket(AF_INET,SOCK_DGRAM,0);
22         if(sock==-1)
23         {
24                 cout<<"socket error"<<endl;
25                 return -1;
26         }
27         memset(&mcast_addr,0,sizeof(mcast_addr));
28         mcast_addr.sin_family=AF_INET;
29         mcast_addr.sin_addr.s_addr=inet_addr(MCAST_ADDR);
30         mcast_addr.sin_port=htons(MCAST_PORT);
31         while(1)
32         {       //向局部多播地址发送多播内容
33                 int n=sendto(sock,MCAST_DATA,sizeof(MCAST_DATA),0,(struct sockaddr*)&mcast_addr,sizeof(mcast_addr));
34                 if(n<0)
35                 {
36                         cout<<"send error"<<endl;
37                         return -2;
38                 }
39                 else
40                 {
41                         cout<<"send message is going ...."<<endl;
42                 }
43                 sleep(MCAST_INTERVAL);
44 
45         }
46         return 0;
47 }

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<stdlib.h>
 4 #include<string.h>
 5 #include<sys/types.h>
 6 #include<unistd.h>
 7 #include<sys/socket.h>
 8 #include<netdb.h>
 9 #include<arpa/inet.h>
10 #include<netinet/in.h>
11 #define MCAST_PORT 8888
12 #define MCAST_ADDR "224.0.0.88" /*一个局部连接多播地址，路由器不进行转发*/
13 #define MCAST_INTERVAL 5  //发送时间间隔
14 #define BUFF_SIZE 256   //接收缓冲区大小
15 using namespace std;
16 int main()
17 {
18         int sock;
19         struct sockaddr_in local_addr;
20         int err=-1;
21         sock=socket(AF_INET,SOCK_DGRAM,0);
22         if(sock==-1)
23         {
24                 cout<<"sock error"<<endl;
25                 return -1;
26         }
27         /*初始化地址*/
28         local_addr.sin_family=AF_INET;
29         local_addr.sin_addr.s_addr=htonl(INADDR_ANY);
30         local_addr.sin_port=htons(MCAST_PORT);
31         /*绑定socket*/
32         err=bind(sock,(struct sockaddr*)&local_addr,sizeof(local_addr));
33         if(err<0)
34         {
35                 cout<<"bind error"<<endl;
36                 return -2;
37         }
38         /*设置回环许可*/
39         int loop=1;
40         err=setsockopt(sock,IPPROTO_IP,IP_MULTICAST_LOOP,&loop,sizeof(loop));
41         if(err<0)
42         {
43                 cout<<"set sock error"<<endl;
44                 return -3;
45         }
46         struct ip_mreq mreq;/*加入广播组*/
47         mreq.imr_multiaddr.s_addr=inet_addr(MCAST_ADDR);//广播地址
48         mreq.imr_interface.s_addr=htonl(INADDR_ANY); //网络接口为默认
49         /*将本机加入广播组*/
50         err=setsockopt(sock,IPPROTO_IP,IP_ADD_MEMBERSHIP,&mreq,sizeof(mreq));
51         if(err<0)
52         {
53                 cout<<"set sock error"<<endl;
54                 return -4;
55         }
56         int times=0;
57         socklen_t addr_len=0;
58         char buff[BUFF_SIZE];
59         int n=0;
60         /*循环接受广播组的消息，5次后退出*/
61         for(times=0;;times++)
62         {
63                 addr_len=sizeof(local_addr);
64                 memset(buff,0,BUFF_SIZE);
65                 n=recvfrom(sock,buff,BUFF_SIZE,0,(struct sockaddr*)&local_addr,&addr_len);
66                 if(n==-1)
67                 {
68                         cout<<"recv error"<<endl;
69                         return -5;
70                 }
71                 /*打印信息*/
72                 printf("RECV %dst message from server : %s\n",times,buff);
73                 sleep(MCAST_INTERVAL);
74         }
75         /*退出广播组*/
76         err=setsockopt(sock,IPPROTO_IP,IP_DROP_MEMBERSHIP,&mreq,sizeof(mreq));
77         close(sock);
78         return 0;
79 }