Linux网络编程之基于UDP实现可靠的文件传输示例(2)

/************************************************************************* 
  > File Name: client.c 
  > Author: SongLee 
 ************************************************************************/ 
#include<sys/types.h> 
#include<sys/socket.h> 
#include<unistd.h> 
#include<netinet/in.h> 
#include<arpa/inet.h> 
#include<stdio.h> 
#include<stdlib.h> 
#include<errno.h> 
#include<netdb.h> 
#include<stdarg.h> 
#include<string.h> 
 
#define SERVER_PORT 8000 
#define BUFFER_SIZE 1024 
#define FILE_NAME_MAX_SIZE 512 
 
/* 包头 */ 
typedef struct  
{ 
  int id; 
  int buf_size; 
}PackInfo; 
 
/* 接收包 */ 
struct RecvPack 
{ 
  PackInfo head; 
  char buf[BUFFER_SIZE]; 
} data; 
 
 
int main() 
{ 
  int id = 1; 
 
  /* 服务端地址 */ 
  struct sockaddr_in server_addr; 
  bzero(&server_addr, sizeof(server_addr)); 
  server_addr.sin_family = AF_INET; 
  server_addr.sin_addr.s_addr = inet_addr("127.0.0.1"); 
  server_addr.sin_port = htons(SERVER_PORT); 
  socklen_t server_addr_length = sizeof(server_addr); 
 
  /* 创建socket */ 
  int client_socket_fd = socket(AF_INET, SOCK_DGRAM, 0); 
  if(client_socket_fd < 0) 
  { 
    perror("Create Socket Failed:"); 
    exit(1); 
  } 
 
  /* 输入文件名到缓冲区 */ 
  char file_name[FILE_NAME_MAX_SIZE+1]; 
  bzero(file_name, FILE_NAME_MAX_SIZE+1); 
  printf("Please Input File Name On Server: "); 
  scanf("%s", file_name); 
 
  char buffer[BUFFER_SIZE]; 
  bzero(buffer, BUFFER_SIZE); 
  strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE?BUFFER_SIZE:strlen(file_name)); 
 
  /* 发送文件名 */ 
  if(sendto(client_socket_fd, buffer, BUFFER_SIZE,0,(struct sockaddr*)&server_addr,server_addr_length) < 0) 
  { 
    perror("Send File Name Failed:"); 
    exit(1); 
  } 
 
  /* 打开文件，准备写入 */ 
  FILE *fp = fopen(file_name, "w"); 
  if(NULL == fp) 
  { 
    printf("File:\t%s Can Not Open To Write\n", file_name);  
    exit(1); 
  } 
 
  /* 从服务器接收数据，并写入文件 */ 
  int len = 0; 
  while(1) 
  { 
    PackInfo pack_info; 
 
    if((len = recvfrom(client_socket_fd, (char*)&data, sizeof(data), 0, (struct sockaddr*)&server_addr,&server_addr_length)) > 0) 
    { 
      if(data.head.id == id) 
      { 
        pack_info.id = data.head.id; 
        pack_info.buf_size = data.head.buf_size; 
        ++id; 
        /* 发送数据包确认信息 */ 
        if(sendto(client_socket_fd, (char*)&pack_info, sizeof(pack_info), 0, (struct sockaddr*)&server_addr, server_addr_length) < 0) 
        { 
          printf("Send confirm information failed!"); 
        } 
        /* 写入文件 */ 
        if(fwrite(data.buf, sizeof(char), data.head.buf_size, fp) < data.head.buf_size) 
        { 
          printf("File:\t%s Write Failed\n", file_name); 
          break; 
        } 
      } 
      else if(data.head.id < id) /* 如果是重发的包 */ 
      { 
        pack_info.id = data.head.id; 
        pack_info.buf_size = data.head.buf_size; 
        /* 重发数据包确认信息 */ 
        if(sendto(client_socket_fd, (char*)&pack_info, sizeof(pack_info), 0, (struct sockaddr*)&server_addr, server_addr_length) < 0) 
        { 
          printf("Send confirm information failed!"); 
        } 
      } 
      else 
      { 
 
      } 
    } 
    else 
    { 
      break; 
    } 
  } 
 
  printf("Receive File:\t%s From Server IP Successful!\n", file_name); 
  fclose(fp); 
  close(client_socket_fd); 
  return 0; 
}