TCP/IP网络编程——基于TCP的半关闭（完成文件传输）

半关闭：只断开一个流

file_client.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUF_SIZE 30

void error_handling(char *message);

int main(int argc, char *argv[])
{
  int sock;
  struct sockaddr_in serv_addr;
  FILE *fp;
  int read_cnt;
  char buf[BUF_SIZE];
  
  if(argc!=3)
  {
    exit(1);
  }
  
  fp=fopen("receive.dat", "wb");
  sock=socket(PF_INET, SOCK_STREAM, 0);
  if(sock == -1)
    error_handling("socket error!");
  
  memset(&serv_addr, 0, sizeof(serv_addr));
  serv_addr.sin_family = AF_INET;
  serv_addr.sin_addr.s_addr = inet_addr(argv[1]);
  serv_addr.sin_port = htons(atoi(argv[2]));

  if(connect(sock, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) == -1)
    error_handling("connect error");
  else
    puts("Connected.....");
  //从服务器接受数据并写入文件
  while((read_cnt=read(sock, buf, BUF_SIZE))!=0)
    fwrite((void*)buf, 1, read_cnt, fp);
  
  //接收完毕后返回thank you
  puts("receive file data:");
  write(sock, "thank you", 10);
  
  fclose(fp);
  close(sock);
  
  return 0;
}

void error_handling(char *message)
{
  fputs(message, stderr);
  fputc('\n', stderr);
  exit(1);
}

file_server.c

//利用TCP发送文件
//shutdown()半关闭的实现
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUF_SIZE 30

void error_handling(char *message);

int main(int argc, char *argv[])
{
  int serv_sock;
  int clnt_sock;
  
  struct sockaddr_in serv_addr;
  struct sockaddr_in clnt_addr;
  socklen_t clnt_addr_size;
  
  int read_cnt;
  FILE *fp;
  char buf[BUF_SIZE];
  
  if(argc!=2)
  {
    exit(1);
  }

  fp=fopen("file_server.c", "rb");
  serv_sock=socket(PF_INET, SOCK_STREAM, 0);
  if(serv_sock == -1)
    error_handling("socket error!");

  memset(&serv_addr, 0, sizeof(serv_addr));
  serv_addr.sin_family = AF_INET;	//IPV4协议族
  serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);	//主机字节序（host）转换成网络字节序（net）（大端序）
  serv_addr.sin_port = htons(atoi(argv[1]));	//端口号
  if(bind(serv_sock, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) == -1)
    error_handling("bind error");

  if(listen(serv_sock, 5) == -1)
    error_handling("listen error");

  clnt_addr_size = sizeof(clnt_addr);
  clnt_sock=accept(serv_sock, (struct sockaddr*) &clnt_addr, &clnt_addr_size);
  if(clnt_sock == -1)
    error_handling("accept error");
  
  while(1)
  {
    //循环发送，每次发BUF_SIZE大小的数据，直到发完才会跳出循环
    read_cnt=fread((void*)buf, 1, BUF_SIZE, fp);
    if(read_cnt<BUF_SIZE)
    {
      write(clnt_sock, buf, read_cnt);
      break;
    }
    write(clnt_sock, buf, BUF_SIZE);
  }
  //半关闭：关闭输出流
  shutdown(clnt_sock, SHUT_WR);
  read(clnt_sock, buf, BUF_SIZE);
  printf("message from client: %s \n", buf);
  
  fclose(fp);
  close(clnt_sock);
  close(serv_sock);
  
  return 0;
}

void error_handling(char *message)
{
  fputs(message, stderr);
  fputc('\n', stderr);
  exit(1);
}