两台Linux虚拟机socket通信(Version 1.0)

叁歲伎倆 2021-12-13 17:41 225阅读 0赞

下面的两个程序实现了这样的功能: 客户端每1s产生一个随机数, 之后将产生的随机数转为字符串类型, 发送至服务端; 服务端在接收到数据后通过printf()函数将这个随机数显示到终端. 这个程序的思路可用于PC机和ARM开发板间的数据通信.

// server.c 服务端
    #include <stdio.h>
    #include <stdlib.h>
    #include <errno.h>
    #include <unistd.h>
    #include <string.h>
    #include <sys/types.h>
    #include <netinet/in.h>
    #include <sys/socket.h>
    #include <sys/wait.h>
    #include <arpa/inet.h> 
    #define SERVPORT 3333
    #define BACKLOG 10
    int main()
    {	
        int sockfd,client_fd;
        int recvbytes;
        int sin_size;
        char buf[50];
        struct sockaddr_in my_addr;    
        struct sockaddr_in remote_addr; 
        sockfd = socket(AF_INET, SOCK_STREAM, 0);//建立socket --
        my_addr.sin_family=AF_INET;//AF_INET地址族
        my_addr.sin_port=htons(SERVPORT);//设定端口号(host -> networks)
        my_addr.sin_addr.s_addr = INADDR_ANY;//32位IPv4地址
        bzero(&(my_addr.sin_zero),8); //置前8个字节为0
        if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) 
         {
      	  perror("bind 出错！");		
    	  exit(1);	
         }
        if (listen(sockfd, BACKLOG) == -1) //监听socket连接，设置队列中最多拥有连接个数为10  --
         {	
    	  perror("listen 出错！");	
            exit(1);     
         }
        while(1)
         {
    	  sin_size = sizeof(struct sockaddr_in);//记录sockaddr_in结构体所占字节数
    	  if ((client_fd = accept(sockfd, (struct sockaddr *)&remote_addr, &sin_size)) == -1) //accept()缺省是阻塞函数，阻塞到有连接请求为止 --
              {	
    	      perror("accept error");		
    	      continue;		
    	  }
    	  printf("收到一个连接来自： %s\n", inet_ntoa(remote_addr.sin_addr));
    	  if (!fork()) 
              { 
    		if (send(client_fd, "连接上了 \n", 26, 0) == -1) //--		
    		    perror("send 出错！");	  
    		//receive pieces of message from host
    		while(1)
    		{
    		    recvbytes = recv(client_fd, buf, 50, 0);
    		    buf[recvbytes] = '\0';
    		    if(recvbytes == 0)//indicating that the client has been off
    		    {
    			printf("connection to %s closed.\n",inet_ntoa(remote_addr.sin_addr));
    			break;
    		    }
    		    printf("%s\n", buf);
    		    sleep(1);
    		}
    		
                close(client_fd);	
                exit(0);		
              }
    	  close(client_fd);
         }
    }

// client.c 客户端
    #include <stdio.h>
    #include <stdlib.h>
    #include <errno.h>
    #include <string.h>
    #include <unistd.h>
    #include <netdb.h>
    #include <sys/types.h>
    #include <netinet/in.h>
    #include <sys/socket.h>
    #include <arpa/inet.h>
    #include <time.h>
    #define SERVPORT 3333
    #define MAXDATASIZE 100
    int random_number()//generating a random number
    {
        int a;
        srand((unsigned)time(NULL));
        a = rand();
        return a;
    }
    int main(int argc, char *argv[])
    {
        int sockfd, recvbytes;
        int value = 0;
        char buf[MAXDATASIZE];
        struct hostent *host;
        struct sockaddr_in serv_addr;
        if(argc < 2) 
         {
    	  fprintf(stderr,"Please enter the server's hostname!\n");
    	  exit(1);	
         }
        if((host=gethostbyname(argv[1]))==NULL)
         {
    	  herror("gethostbyname error！");	
    	  exit(1);	
         }
        if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)//建立socket --
         { 
    	  perror("socket create error！");	
    	  exit(1);	
         }
        serv_addr.sin_family=AF_INET;
        serv_addr.sin_port=htons(SERVPORT);
        serv_addr.sin_addr = *((struct in_addr *)host->h_addr);
        bzero(&(serv_addr.sin_zero),8);
        if(connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(struct sockaddr)) == -1) //请求连接 --
         {
    	  perror("connect error！");
    	  exit(1);
         }
        //successful connection
        if((recvbytes=recv(sockfd, buf, MAXDATASIZE, 0)) ==-1)//接收数据 --
         {
    	  perror("connect 出错！");
    	  exit(1);
         }
        buf[recvbytes] = '\0';
        printf("收到: %s",buf);
        //send pieces of message to server
        while(1)
        {
    	//generating a random number and sending it to the host
    	value = random_number();
            sprintf(buf, "%d", value);//int to string
            send(sockfd, buf, (int)strlen(buf), 0);
    	//every one second client sends a random number converted to string to host
    	sleep(1);
        }
        close(sockfd);//关闭连接 --
    }

server端等待连接.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70][]

client端请求连接并发送数据至server端.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70 1][]

server端收到数据并显示到终端.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70 2][]

在client端结束连接.

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70 3][]

server端提示该client端连接结束, 并继续等待新的连接请求.

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