1 #include<stdio.h>
 2 #include<unistd.h>
 3 #include<stdlib.h>
 4 #include <strings.h>
 5 #include<string.h>
 6 #include<sys/socket.h>
 7 #include<arpa/inet.h>
 8 #include<net/if.h>
 9 
10 #define SERVER_PORT 8000 //服务端端口无关紧要
11 #define MAXLINE 1500
12 
13 #define BROADCAST_IP "192.168.23.255"//所在局域网的广播IP
14 #define CLIENT_PORT 9000 //客户端端口必须指定
15 
16 int main(int argc,char* argv[])
17 {
18     int sockfd;
19     struct sockaddr_in servaddr,clieaddr;
20     char buf[MAXLINE];
21     //构造用于UDP通信的套接字
22     sockfd = socket(AF_INET,SOCK_DGRAM,0);
23 
24     bzero(&servaddr,sizeof(servaddr));
25     servaddr.sin_family = AF_INET;               //IPv4
26     servaddr.sin_addr.s_addr = htonl(INADDR_ANY);//本地任意有效IP
27     servaddr.sin_port = htons(SERVER_PORT);
28 
29     bind(sockfd,(struct sockaddr*)&servaddr,sizeof(servaddr));
30 
31     int flag = 1;
32     setsockopt(sockfd,SOL_SOCKET,SO_BROADCAST,&flag,sizeof(flag));
33 
34     //构造client地址 IP+端口 
35     bzero(&clieaddr,sizeof(clieaddr));
36     clieaddr.sin_family = AF_INET;
37     inet_pton(AF_INET,BROADCAST_IP,&clieaddr.sin_addr.s_addr);
38     clieaddr.sin_port = htons(CLIENT_PORT);
39 
40     int i = 0;
41     while(1)
42     {
43         sprintf(buf,"服务端发送了广播%d 次\n",i++);
44         sendto(sockfd,buf,strlen(buf),0,(struct sockaddr*)&clieaddr,sizeof(clieaddr));
45         sleep(1);
46     }
47     close(sockfd);
48 
49     return 0;
50 }

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 #include<strings.h>
 4 #include<string.h>
 5 #include<sys/socket.h>
 6 #include<unistd.h>
 7 #include<sys/types.h> 
 8 #include<arpa/inet.h>
 9 
10 #define SERVER_PORT 8000
11 #define CLIENT_PORT 9000
12 #define MAXLINE 4096
13 
14 int main(int argc,char* argv[])
15 {
16     struct sockaddr_in localaddr;
17     int confd;
18     ssize_t len;
19     char buf[MAXLINE];
20     //1.创建一个socket
21     confd = socket(AF_INET,SOCK_DGRAM,0);
22     //初始化本地地址
23     bzero(&localaddr,sizeof(localaddr));
24     localaddr.sin_family = AF_INET;
25     inet_pton(AF_INET,"0.0.0.0",&localaddr.sin_addr.s_addr);
26     localaddr.sin_port = htons(CLIENT_PORT);
27 
28     int ret = bind(confd,(struct sockaddr*)&localaddr,sizeof(localaddr));
29     if(ret == 0)
30     {
31         printf("...bind ok...\n");
32     }
33     while(1)
34     {
35         len = recvfrom(confd,buf,sizeof(buf),0,NULL,0);
36         write(STDOUT_FILENO,buf,len);
37     }
38     close(confd);
39 
40     return 0;
41 }