tcpserver.c

socket编程TCP server端与client端连通程序

/*  
Linux下小的socket程序，分为客户端和服务器端,服务端开一个端口(2000),做为一个daemon,等待客户 的连接请求.一旦有客户连接,服务器端打印出客户端的IP地址和端口,并且向服务器端发送欢迎信息和时间.下面是服务端的代码(tcpserver.c).由于这只是个简单的程序，所以只用了单线程实现!
*/


/*
 * Tcp server program, It is a simple example only.

 * LinShouGang 20081007 

 * when client connect to server, send a welcome message and timestamp in server.

 */

 

#include <stdio.h>
#include <sys/socket.h>
#include <unistd.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <time.h>
 
#define SERVER_PORT 20000              // define the defualt connect port id
#define LENGTH_OF_LISTEN_QUEUE 10      //length of listen queue in server
#define BUFFER_SIZE 255
#define WELCOME_MESSAGE "welcome to connect the server. "

int main(int argc, char **argv)
{
       int servfd,clifd;
       struct sockaddr_in servaddr,cliaddr;

       if ((servfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
       {
              printf("create socket error!\n");
              exit(1);
       }

       bzero(&servaddr,sizeof(servaddr));
       servaddr.sin_family = AF_INET;
       servaddr.sin_port = htons(SERVER_PORT);
       servaddr.sin_addr.s_addr = htons(INADDR_ANY);
 
       if (bind(servfd,(struct sockaddr*)&servaddr,sizeof(servaddr))<0)
       {
              printf("bind to port %d failure!\n",SERVER_PORT);
              exit(1);
       }

       if (listen(servfd,LENGTH_OF_LISTEN_QUEUE) < 0)
       {
              printf("call listen failure!\n");
              exit(1);
       }

       while (1)
       {      //server loop will nerver exit unless any body kill the process

              char buf[BUFFER_SIZE];
              long timestamp;
              socklen_t length = sizeof(cliaddr);

              clifd = accept(servfd,(struct sockaddr*)&cliaddr,&length);
              if (clifd < 0)
              {
                     printf("error comes when call accept!\n");
                     break;
              }

              strcpy(buf,WELCOME_MESSAGE);
              //inet_ntop(INET_ADDRSTRLEN,cliaddr.sin_addr,buf,BUFFER_SIZE);

              printf("from client,IP:%s,Port:%d\n",inet_ntoa(cliaddr.sin_addr),ntohs(cliaddr.sin_port));

              timestamp = time(NULL);
              strcat(buf,"timestamp in server:");
              strcat(buf,ctime(&timestamp));
              send(clifd,buf,BUFFER_SIZE,0);
              close(clifd);                         
       }//exit

       close(servfd);
       return 0;
}