进程通信之套接字（TCP）

 1 #include<stdio.h>
 2 #include<sys/socket.h>//套接字
 3 #include<netinet/in.h>
 4 #include<string.h>
 5 #include<stdlib.h>
 6 #include<arpa/inet.h>//字节序转换
 7 #include<unistd.h>
 8 
 9 //可以正常运行了；
10 
11 #define SERVPORT 6666
12 
13 int main()
14 {
15     int listenfd,connfd;//两个套接口
16     struct  sockaddr_in servaddr,cliaddr;
17     socklen_t clilen;//这个定义的客户端套接字长度
18     char buf[100] = {0};
19     int bytes_recv;
20     //建立套接口
21     //第三个参数默认为0
22     listenfd = socket(AF_INET,SOCK_STREAM,0);
23     
24     //配置地址
25     bzero(&servaddr,sizeof(servaddr));
26     servaddr.sin_family = AF_INET;
27     servaddr.sin_port = htons(SERVPORT);
28     servaddr.sin_addr.s_addr = htonl(INADDR_ANY);//或者是单一地址
29 
30     int opt = 1;
31     setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));//端口复用
32 
33     bind(listenfd,(struct sockaddr *)&servaddr,sizeof(servaddr));//强制类型转换
34 
35     listen(listenfd,1024);//队列数
36 
37     for(;;)//这个循环结束不了，其实服务器也不用停啊
38     {
39         clilen = sizeof(cliaddr);
40         connfd =  accept(listenfd,(struct sockaddr *)&cliaddr,&clilen);
41         printf("accept client ip is %s,port is %u\n",inet_ntoa(cliaddr.sin_addr),cliaddr.sin_port);//port短整型
42 
43         while(1)
44         {
45             bzero(buf,sizeof(buf));
46             bytes_recv = recvfrom(connfd,buf,sizeof(buf),0,(struct sockaddr *)&cliaddr,&clilen);
47             if(0 == bytes_recv)
48             {
49                 printf("client offline!");
50                 break;
51             }
52             sendto(connfd,buf,bytes_recv,0,(struct sockaddr *)&cliaddr,clilen);
53         }
54         close(connfd);
55     }
56 
57     close(listenfd);
58 
59     return 0;
60 }

 1 #include<stdio.h>
 2 #include<sys/socket.h>
 3 #include<netinet/in.h>
 4 #include<string.h>
 5 #include<stdlib.h>
 6 #include<arpa/inet.h>//字节序转换
 7 #include<unistd.h>
 8 
 9 #define SERVPORT 6666
10 
11 int main(int argc,char **argv)
12 {
13     int sockfd;
14     struct sockaddr_in servaddr;
15     int bytes_recv;
16     char readline[100];
17     char sendline[100];
18 
19 //    if(argc != 2)
20 //  {
21   //      printf("please input the IP\n");
22     //    exit(0);
23     //}
24     //创建套接字
25     sockfd = socket(AF_INET,SOCK_STREAM,0);
26 
27     bzero(&servaddr,sizeof(servaddr));
28     servaddr.sin_family = AF_INET;
29     servaddr.sin_port = htons(SERVPORT);
30      //inet_aton(argv[1],&servaddr.sin_addr);
31     servaddr.sin_addr.s_addr = inet_addr("192.168.138.137");//直接绑定服务器端地址
32      
33     
34     //连接
35     connect(sockfd,(struct sockaddr *)&servaddr,sizeof(servaddr));
36     while((fgets(sendline,100,stdin)) != NULL)//等一会可以结束
37     {//减一是因为fgets读入了\n; 第四个参数好像也是flag
38         sendto(sockfd,sendline,strlen(sendline)-1,0,(struct sockaddr *)&servaddr,sizeof(servaddr));
39         bytes_recv = recvfrom(sockfd,readline,sizeof(readline),0,NULL,NULL);
40 
41         printf("recv character:%d\n",bytes_recv);
42         
43         bzero(readline,sizeof(readline));
44         bzero(sendline,sizeof(readline));
45 
46     }
47     
48     
49     close(sockfd);
50 
51     
52     return 0;
53 }