TCP网络编程

来源：互联网发布：c语言 ip地址合法性编辑：程序博客网时间：2024/06/08 18:17

TCP网络编程基本模型：
UNIX环境高级编程435页。
程序例程：
服务器：
#include
#include
#include
#include
#include
#include

#define portnumber 3333

int main( int argc, char **argv )
{
   int      sockfd;
    int   new_fd;
    int   sin_size;
    int   nbytes;
   char   buffer[1024];
    structsockaddr_in   server_addr;
    structsockaddr_in   client_addr;

    if((sockfd=socket(AF_INET, SOCK_STREAM, 0)) == -1 )
    {
       perror("socket error\n" );
       exit( 1);
    }
    bzero(&server_addr, sizeof(struct sockaddr_in) );
   server_addr.sin_family = AF_INET;
   server_addr.sin_addr.s_addr = htonl( INADDR_ANY );
   server_addr.sin_port = htons( portnumber );
    if(bind(sockfd, (struct sockaddr *)(&server_addr),sizeof(struct sockaddr)) == -1 )
    {
       perror("bind error\n" );
       exit( 1);
    }
    if(listen(sockfd, 5) == -1 )
    {
       perror("listen error\n" );
       exit( 1);
    }

    sin_size =sizeof( struct sockaddr_in );
    while( 1)
    {
       if((new_fd=accept(sockfd, (struct sockaddr*)(&client_addr), &sin_size)) == -1)
       {
          perror("accept error\n" );
          exit( 1);
       }
       fprintf(stdout," server get %s ", inet_ntoa(client_addr.sin_addr) );

       if((nbytes=read(new_fd, buffer, 1024)) == -1 )
       {
          perror("read error\n" );
          exit( 1);
       }
      buffer[nbytes] = '\0';
       printf("received %s\n", buffer );

       close(new_fd );
    }

    exit( 0);
}

客户端：
#include
#include
#include
#include
#include

#define portnumber 3333

int main( int argc, char **argv )
{
    intsockfd;
    charbuffer[1024];
    structsockaddr_in server_addr;

    sockfd =socket( AF_INET, SOCK_STREAM, 0 );

    bzero(&server_addr, sizeof(server_addr) );
   server_addr.sin_family = AF_INET;
   server_addr.sin_port = htons( portnumber );
   server_addr.sin_addr.s_addr = inet_addr( "127.0.1.1" );
    if(connect(sockfd, (struct sockaddr *)(&server_addr),sizeof(struct sockaddr)) == -1 )
    {
       perror("connet error\n" );
       exit( 1);
    }

    printf("please input char: \n");

    fgets(buffer, 1024, stdin );
    write(sockfd, buffer, strlen(buffer) );

    close(sockfd );
    exit( 0);
}

遇到的问题：
刚开始由于在客户端中没有建立套接字，即
sockfd = socket( AF_INET, SOCK_STREAM, 0);这一句，导致connect文件总是返回pemission denied。

多线程TCP编程：
while( 1 )
   {
       if((new_fd=accept(sockfd, (struct sockaddr*)(&client_addr), &sin_size)) == -1)
       {
          perror("accept error\n" );
          exit( 1);
       }
       fprintf(stdout," server get %s\n ", inet_ntoa(client_addr.sin_addr));
       if( fork()== 0 )
       {

       if((nbytes=read(new_fd, buffer, 1024)) == -1 )
       {
          perror("read error\n" );
          exit( 1);
       }
      buffer[nbytes] = '\0';
       printf("received %s\n", buffer );

       close(new_fd );
       }
    }
主要思想是一个线程处理连接任务，连接后的事务用创建的子进程处理

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