ECHO网络程序的演变史 (6) --- 多进程 TCP Echo

Andrew Huang 转载请注明作者及联络方式

一.多进程实现的原因
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二.多进程实现的代码
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多进程的服务器 udp_echo_svr.c

/*
  TCP MultiProcess Echo Server
 
 Author :Andrew Huang

 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <pthread.h>


#include <stdlib.h>
#include <stdio.h>
#include <string.h>

static void process_fn(int client_fd)
{
   
   int len;
        char buf[1024];

     while(1)
        {
   //第五步：与客户端在新的socket进行通讯

             //注意，是从client_fd,

               len = recv(client_fd,buf,sizeof(buf),0);
                  if(len <= 0)
                           break;

                  buf[len] = 0;
                  fprintf(stdout,"RECV(%d):\"%s\"\n",client_fd,buf);
                  
              //第六步：用send把数据照原样发给客户端

                   if(send(client_fd,buf,len,0)<=0)
                             break;
       }
                close(client_fd);
                 fprintf(stdout,"CLOSE socket %d\n",client_fd);
}


int main(int argc ,char * argv[])
{
  unsigned short port = 9000;
   
   int listen_fd ;
   int client_fd;
   pthread_t pth;

   struct sockaddr_in addr; //ipv4的地址结构

   struct sockaddr_in client_addr ;
   socklen_t addr_len;


   int len ;
  
   if(argc >1)
     {
         port = (unsigned short)atoi(argv[1]);
     }

  //第一步：创建一个IPV4,TCP，可以运行所有协议的SOCKET

  listen_fd = socket(PF_INET,SOCK_STREAM,0);
  if(listen_fd == -1)
   {
        perror("socket");
         return -1;
   }


   //第二步:用bind来指定端口

   memset(&addr,0,sizeof(addr));
    addr.sin_port = htons(port); //转成网络序的端口

   addr.sin_family = AF_INET; //ipv4的地址类型

   //addr.sin_addr.s_addr = inet_addr("0.0.0.0"); //bind 的sin_addr表示在哪一个网卡上有效,

   //绑定在0.0.0.0上表示这个SOCKET在所有网卡侦听

   addr.sin_addr.s_addr = INADDR_ANY; //INADDR_ANY = 0 = inet_addr("0.0.0.0")


    if(bind(listen_fd,(const struct sockaddr *)&addr,sizeof(addr)) == -1)
       {
          perror("bind");
            close(listen_fd);
          return -2;
       }

   //第三步： 通知内核里的TCP／IP协议栈，让这个SOCKET开始侦听网络上的请求

   // listen只是通知一下，通知成功立即执行后面代码

     if(listen(listen_fd,20) == -1)
       {
             perror("listen");
        close(listen_fd);
             return -3;
       }


      fprintf(stdout,"TCP MultiProcess Echo Server listen on %d\n",port);
   
      
     while(1)
       {
           memset(&client_addr,0,sizeof(client_addr));
           client_addr.sin_family = AF_INET;
           addr_len = sizeof(client_addr); //必须赋值！


           //第四步：服务器在侦听客户端请求

                printf("accept client ...\n");
           client_fd = accept(listen_fd,(struct sockaddr *)&client_addr,&addr_len);
             if(client_fd == -1)
               {
                  perror("accept");
                     continue;
               }

             fprintf(stdout,"client socket %d,addr %s,port %d\n",client_fd,
                    inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port));


             // pthread_create(&pth,NULL,thread_fn,(void*)client_fd);

             if(fork() == 0)
                 {//子进程负责处理对应联接

                      close(listen_fd);
                      process_fn(client_fd);
                        exit(0);
          
                  }

                 close(client_fd); //父进程关闭client_fd;
          
       }

     printf("exit");
      close(listen_fd);

}


客户端仍采用多线程 udp_echo_cli.c

/*
  TCP MultiThread Echo Client
 
 Author :Andrew Huang

 */


#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <stdio.h>
#include <string.h>


int main(int argc ,char * argv[])
{
   unsigned short port = 9000;
   
   int sock ;
    char ipaddr[32] = "127.0.0.1";
    char buf[32] = "hello server";
    struct sockaddr_in serv_addr;
    int len;

     if(argc >1)
     {
         port = (unsigned short)atoi(argv[1]);
     }

    if(argc >2)
     {
          memset(ipaddr,0,sizeof(ipaddr));
         strncpy(ipaddr,argv[2],sizeof(ipaddr)-1);
     }

    if(argc > 3)
       {
            memset(buf,0,sizeof(buf));
         strncpy(buf,argv[3],sizeof(buf)-1);
        }


   printf("connect server %s:%d,buf %s\n",ipaddr,port,buf);

  //第一步：创建一个IPV4,TCP，可以运行所有协议的SOCKET

   sock = socket(PF_INET,SOCK_STREAM,0);
   if(sock == -1)
      {
          perror("socket");
          return -1;
      }


    //第二步:对于客户端,port可用任意一个编号,如果不使用bind，协议栈会自动分配没用的端口0

    // 省略bind ....


   //第三步：用connect()去联接服务器

    memset(&serv_addr,0,sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(port);
    serv_addr.sin_addr.s_addr = inet_addr(ipaddr);
 
     //printf("ipaddr %s,s_addr %x\n",ipaddr,ntohl( serv_addr.sin_addr.s_addr));


     if(connect(sock,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) == -1)
        {
            perror("connect");
              close(sock);
              return -2;
        }

      while(1)
        {
           
          //键盘输入

         if(fgets(buf,sizeof(buf)-1,stdin)== NULL)
                 break;

           //如果直接输入回车则退出

          if(buf[0]== '\n')
                   break;

        if(send(sock,buf,strlen(buf)+1,0)<= 0)
           {
               perror("send");
              close(sock);
              return -3;
           }

           len = recv(sock,buf,sizeof(buf),0);
           if(len >0)
             {
                 buf[len] = 0;
                 printf("SERVER:%s\n",buf);
             }

          }
              //关闭socket

            close(sock);
           
   
}