tcp套接字编程

server.c

#include<stdio.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<errno.h>
#include<unistd.h>
#include<string.h>
#include<sys/types.h>
#include<arpa/inet.h>

#define _PORT_ 9999

#define _BACKLOG_ 10


int main()
{
   
    int sock = socket (AF_INET, SOCK_STREAM, 0);     //SOCK_STREAM  TCP协议 面向字节流   AF_INET 表示IPv4 addresss.
   
    if( sock<0 )
    {
        printf("creat socket error ,errno is :%d, errstring is :%s",errno, strerror(errno));
        return 1; 
    }

    struct sockaddr_in server_socket,client_socket;
    
    bzero(&server_socket, sizeof(server_socket)); //初始化server_socket结构体。

    server_socket.sin_family = AF_INET;
    server_socket.sin_addr.s_addr = htonl(INADDR_ANY);     // INADDR_ANY  is meaning any of my IP address.  Its value can be get by system.
    server_socket.sin_port = htons(_PORT_);                

    if(bind(sock, (struct sockaddr*)&server_socket, sizeof(server_socket) )< 0)
    {
        printf("bind error, error code is %d, error string is :%s \n",errno, strerror(errno) );
        close(sock);
        return 2;
    }

    if(listen(sock,_BACKLOG_)<0)
    {
        printf("listen error, error code is:%d , error string is : %s \n", errno, strerror(errno));
        return 3;
    }
    //socket 与 address 和 port 完成绑定。
   
    printf("bind and listen success, wait accept ~ ~ ~\n");
    
   
    while(1)
    {
        socklen_t len=sizeof(client_socket);
       
        int client_sock= accept(sock, (struct sockaddr *)&client_socket, &len);   // 创建了新的socket文件 来接受客户的信息
        
        if(client_sock<0)
        {
            printf("accept error, errno is :%d, errstring is :%s \n", errno ,strerror(errno));
            close(sock);
            return 4;
        }

         // 链接成功 打印客户端的 IP 和 Port
        
        char buf_ip[INET_ADDRSTRLEN];
        memset(buf_ip, '\0', sizeof(buf_ip));
        inet_ntop(AF_INET, &client_socket.sin_addr, buf_ip, sizeof(buf_ip));  //对客户的地址进行提取
       
        printf("get connert, ip is :%s port is :%d \n", buf_ip, ntohs(client_socket.sin_port) );
   

        // 单用户版本  以下为对用户的服务
        while(1)
        {
            char buf[1024];                                              // 定义缓冲区
            memset(buf,'\0', sizeof(buf));                              // 清零缓冲区

            read(client_sock,buf, sizeof(buf));                         //读取用户需求
            printf("client:# %s\n",buf);                                //打印用户发来的消息
            
            memset(buf, '\0',sizeof(buf));                              //再次清零缓冲区
           
            printf("server:$ ");
            fgets(buf,sizeof(buf),stdin);                               //输入信息到buf 
            buf[strlen(buf)-1]='\0';                                   //将末尾的 \n 修改为 \0
            write(client_sock, buf, strlen(buf)+1);                     //将内容写入client_sock
            printf("Massage send to client  please wait ......\n");

        }
           //与用户持续交流

    }
    close(sock);
    return 0;
}

client.c

#include<stdio.h>
#include<string.h>
#include<unistd.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<strings.h>
#include<errno.h>
#include<netinet/in.h>
#include<arpa/inet.h>

#define SERVER_PORT 8080
#define SERVER_IP  "127.0.0.1"


int main()
{
   
   char buf[1024];
   memset(buf,'\0', sizeof(buf));
  
   struct sockaddr_in server_sock;
  
   int sock=socket(AF_INET, SOCK_STREAM, 0);
   bzero(&server_sock, sizeof(server_sock));
   
   server_sock.sin_family=AF_INET;
   inet_pton(AF_INET,SERVER_IP,&server_sock.sin_addr);
   server_sock.sin_port= htons(SERVER_PORT);

   int ret = connect(sock,(struct sockaddr *)&server_sock,sizeof(server_sock));
  
   if(ret<0)
   {
       printf("connerct failed..., errno is :%d, errstring is :%s", errno, strerror(errno));
       return 1;
   }
  
   printf("connerct success ~ ~ ~\n");
  
   while(1)
   {
       printf("client: ");
       fgets(buf, sizeof(buf),stdin);
       buf[strlen(buf)-1] ='\0';
       write(sock, buf, sizeof(buf));
       if(strncasecmp(buf,"quit",4)==0)
       {
           printf("quit!\n");
           break;
       }
       printf("please wait ...... \n");
       read(sock, buf, sizeof(buf));
       printf("server:%s\n", buf);

   }
  
   close(sock);
   return 0;
}