linux-c-tcpサービス帯域タイムアウト処理のc/s

1.server
deepfuture@deepfuture-laptop:~/private/mytest$ ./testtcps
server wait....
............................
server read :deepfuture.iteye.com
 
server send :hello
.....
server read :deepfuture.iteye.com
 
server send :hello
2.client
deepfuture@deepfuture-laptop:~/private/mytest$ ./testtcpc
client send....
client send :deepfuture.iteye.com
client read :hello
deepfuture@deepfuture-laptop:~/private/mytest$ ./testtcpc
client send....
client send :deepfuture.iteye.com
client read :hello
deepfuture@deepfuture-laptop:~/private/mytest$ 
3.source
1)server

#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
//deepfuture.iteye.com
ssize_t readn(int fd,void *ptr,size_t maxcn){//  n   ,maxc      
    size_t noreadcn,readcn;
    char *buf=ptr;

    
    
    noreadcn=maxcn;
    while(noreadcn>0){
       if ( (readcn=read(fd,buf,noreadcn))<0){//   
    
          if (errno==EINTR) {//     ，       
             perror("    ");
             readcn=0;           
          }
          else {return -1;}//      ，      
       }
       else if(readcn==0) break;//EOF
       
       
       noreadcn-=readcn;//    ，            maxc，    ，                     
       buf+=readcn;  
       if (*buf==0) break;//              ，     ，      
       }  


     
    return (maxcn-noreadcn);
}

ssize_t  writen(int fd,void *ptr,size_t maxcn){//  n   
    size_t nowritecn,writecn;
    char *buf=ptr;

    
    nowritecn=maxcn;
    while(nowritecn>0){
       if((writecn=write(fd,buf,nowritecn))<=0){//   
       
          if (errno==EINTR) {//    ，       
             perror("    ");
             writecn=0;             
          }
          else {return -1;}//      ，      
       }

      
       nowritecn-=writecn;
       buf+=writecn;  

       } 

       return (maxcn-nowritecn);
}

int main(void){
    int fd;
    int addresslen;
    struct sockaddr_in address;//      
    int pid;
    int rc;
    fd_set fdset;
    


                  
    //  socket
    fd=socket(AF_INET,SOCK_STREAM,0);//fd socket
    if (fd==-1){//  ，   errno  
        perror("error");//perror     ，  ":"   ，   errno        (      )，        。        
    }
    
    //bind  socket fd    
    address.sin_family=AF_INET;//IPV4  ,AF_INET6 IPV6
    address.sin_addr.s_addr=htonl(INADDR_ANY);//l  32 ，htonl      CPU      
    address.sin_port=htons(1253);//   ，s  16 
    addresslen=sizeof(address);
    

    bind(fd,(struct sockaddr *)&address,addresslen);//bind
    
           //  socket  ，          
           rc=listen(fd,32);//    32   ，    
           //int listen(int sockfd, int backlog)  ：0──  ， -1──  
           //                                                 
           if (rc==-1) {
              perror("listen error");//    
              exit(1);
           }
           printf("server wait....
");           
           while(1){

              struct sockaddr_in clientaddress;
              int address_len;
              int client_sockfd;
              char mybuf[100];    
              char *buf="hello
";  
              struct timeval timeout;//     
              //   2 
              timeout.tv_sec=1;
              timeout.tv_usec=0;
              //  fdset
              FD_ZERO(&fdset);//  fdset
              FD_CLR(fd,&fdset);//  fd   
              FD_SET(fd,&fdset);//    
              //select
              if ((select(fd+1,&fdset,NULL,NULL,&timeout))<0){
                  perror("select error");
                  fflush(stdout);              
              }
              //    ，              

              fflush(stdout);     
              address_len=sizeof(clientaddress);              
              if(FD_ISSET(fd,&fdset)){
                  //       
                 client_sockfd=accept(fd,(struct sockaddr *)&clientaddress,&address_len);//client_sockfd          ，  read write  。client_address         deepfuture.iteye.com
              
              //fork                  
            	  pid=fork();
           	   if (pid<0){//  
            	    printf("error:%s
",strerror(errno));//strerror errno           deepfuture.iteye.com
              		close(client_sockfd);
              	  	exit(1); 
            	}   

             	 if (pid==0){ //                         
             	     close(fd);//                

             		  //     deepfuture.iteye.com
                	  bzero(mybuf,100);                   
             	     readn(client_sockfd,(void *)mybuf,100);
                	  printf("
server read :%s",mybuf);                  
                  	 //                      
               	 	  writen(client_sockfd,(void *)buf,strlen(buf)+1);               
               		   printf("
server send :%s",buf);                
               		   close(client_sockfd);
               		   exit(0);
           		 }
           		  else {//   
                		  close(client_sockfd);//           ，    ，                 ，            client_sockfd           deepfuture.iteye.com     
            	 }                               
            }else{
                  printf(".");
                  fflush(stdout);
            }
       }
 }

 2) client

#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
//deepfuture.iteye.com
ssize_t readn(int fd,void *ptr,size_t maxcn){//  n   ,maxc      
    size_t noreadcn,readcn;
    char *buf=ptr;
    
    
    noreadcn=maxcn;
    while(noreadcn>0){
       if ( (readcn=read(fd,buf,noreadcn))<0){//   
    
          if (errno==EINTR) {//     ，        deepfuture.iteye.com
             perror("    ");
             readcn=0;            
          }
          else {return -1;}//      ，      
       }
       else if(readcn==0) break;//EOF deepfuture.iteye.com
           
       noreadcn-=readcn;//    ，            maxc，    ，                     
       buf+=readcn;   
        if (*buf==0) break;    //              ，     ，        deepfuture.iteye.com
       }   

    return (maxcn-noreadcn);
}

ssize_t writen(int fd,void *ptr,size_t maxcn){//  n   
    size_t nowritecn,writecn;
    char *buf=ptr;
    
    nowritecn=maxcn;
    while(nowritecn>0){
       if((writecn=write(fd,buf,nowritecn))<=0){//   
          if (errno==EINTR) {//    ，       
             perror("    ");
             writecn=0;             
          }
          else {return -1;}//      ，      
       }
    
       nowritecn-=writecn;
       buf+=writecn; 

       }  
       return (maxcn-nowritecn);
}

int main(void){
    int fd;
    int addresslen;
    struct sockaddr_in address;//       deepfuture.iteye.com
    int pid;
    char mybuf[100];        
    char *buf="deepfuture.iteye.com
";
    int rc;


    fd=socket(AF_INET,SOCK_STREAM,0);//  socket
    if (fd==-1){//  ，   errno  
        perror("error");//perror     ，  ":"   ，   errno        (      )，        。    deepfuture.iteye.com     
    }
  
    printf("client send....
");
    fflush(stdout);
    
    //  
    address.sin_family=AF_INET;//IPV4  ,AF_INET6 IPV6 deepfuture.iteye.com
    address.sin_addr.s_addr=inet_addr("127.0.0.1");//l  32 ，htonl      CPU      
    address.sin_port=htons(1253);//   ，s  16  deepfuture.iteye.com
    addresslen=sizeof(address);        
    rc=connect(fd,(struct sockaddr *)&address,addresslen);//      deepfuture.iteye.com
    if (rc==-1){//rc=0  ，rc=-1   deepfuture.iteye.com
      perror("    ");
      exit(1);
    }
    //     
    writen(fd,(void *)buf,strlen(buf)+1);
    printf("client send :%s
",buf);      
    //    
    bzero(mybuf,100);  
    readn(fd,(void *)mybuf,100); 
    printf("client read :%s
",mybuf); 
    close(fd);
    exit(0);                

 }