tcp网络服务器程序

 

/*tcp_server.c*/
#include<stdlib.h>
#include<stdio.h>
#include<errno.h>
#include<string.h>
#include<netdb.h>
#include<sys/types.h>
#include<netinet/in.h>
#include<sys/socket.h>

#define portnumber 3333

int main()
{
 int sockfd,new_fd;
 struct sockaddr_in server_addr;
 struct sockaddr_in client_addr;
 int sin_size;
 int nbytes;
 char buffer[1024];
 
 /*服务器端开始创建套接字描述符*/
 if((sockfd=socket(AF_INET,SOCK_STREAM,0))<0)
 {
  fprintf(stderr,"socket error:%s\n\a",strerror(errno));
  exit(1);
 }
 /*服务器端填充sockaddr结构*/
 bzero(&server_addr,sizeof(struct sockaddr_in));/*初始化，置0*/
 server_addr.sin_family=AF_INET;//IPv4
 server_addr.sin_addr.s_addr=htonl(INADDR_ANY);//服务器程序可以运行在任何ip的主机上
 //server_addr.sin_addr.s_addr=inet_addr("192.168.1.1");
 server_addr.sin_port=htons(portnumber);
 
 /*捆绑sockfd描述符到ip地址*/
 if(bind(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1)
 {
  fprintf(stderr,"bind error:%s\n\a",strerror(errno));
  exit(1);
 }
 /*设置允许连接的最大客户数*/
 if(listen(sockfd,5)==-1)
 {
  fprintf(stderr,"listen error:%s\n\a",strerror(errno));
  exit(1);
 }
 while(1)
 {
  /*服务器阻塞，直到客户程序建立连接*/
  sin_size=sizeof(struct sockaddr_in);
  if(new_fd=accept(sockfd,(struct sockaddr*)(&client_addr),&sin_size)==-1)
  {
   fprintf(stderr,"server error:%s\n\a",strerror(errno));
   exit(1);
  }
  fprintf(stderr,"server get connecttion from %s\n",inet_ntoa(client_addr.sin_addr));
  if((nbytes=read(new_fd,buffer,1024))==-1)
  {
   fprintf(stderr,"read error:5s\n",strerror(errno));
   exit(1);
  }
  buffer[nbytes]='\0';
  printf("server received %s\n",buffer);
  /*这个通讯已经结束*/
  close(new_fd);
  /*循环下一个*/
 }
 /*结束通讯*/
 close(sockfd);
 exit(0);
}