myftpserver.c~

简单ftp协议实现

#include "common.h"

#define LOCAL_IP "192.168.0.74"
char valid_user[]="fancy9";
char valid_pass[]="fancy9";
int current_data_port;
int lsock;
int asock;
int dlsock;
int dtsock;
struct sockaddr_in serveraddr;
struct sockaddr_in client;
struct sockaddr_in serverdl;
struct sockaddr_in serverdt;

struct server_state
{
  short client_port;
  unsigned long client_ip;
  char current_dir[2048];
  char path_prefix[2048];
  char user[256];
  char pass[256];
  char type[2];
  int isPassive;
  char mode[256];
}ss;

void init_server_state()
{
  //  printf("[Fancy ftpd]Connected to %s:%d\n", inet_ntoa(client.sin_addr.s_addr),ntohs(client.sin_port));
  reply(R220, NULL , asock);
  ss.client_port = client.sin_port;
  ss.client_ip = client.sin_addr.s_addr;
  strcpy(ss.current_dir, "/");
  strcpy(ss.path_prefix, ".");
  ss.isPassive = 0;
  strcpy(ss.mode, "ASCII");
}

int begin_listen()
{
  int sock,length;

  sock=socket(AF_INET,SOCK_STREAM,0);
  check_error (sock,"opening stream socket");
  
  serveraddr.sin_family=AF_INET;
  serveraddr.sin_addr.s_addr=htonl(INADDR_ANY);
  serveraddr.sin_port=htons(LISTEN_PORT);
  int opt = 1;
  check_error (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(int)), "setsockopt");
  check_error (bind(sock,(struct sockaddr *)&serveraddr,sizeof( serveraddr)),
	       "binding stream socket");
  
  length=sizeof(serveraddr);
  check_error(getsockname(sock,(struct sockaddr *)&serveraddr,&length)
	      ,"getting socket name");
  
  printf("Socket port # %d\n",ntohs(serveraddr.sin_port));
  
  listen(sock,5);
  return sock;
}

void get_port(char *arg)
{
  int a[6];
  sscanf(arg, "%d,%d,%d,%d,%d,%d", a, a+1, a+2, a+3, a+4, a+5);
  ss.isPassive = 0;
  ss.client_port = (short)((a[4])+(a[5]<<8));
  ss.client_ip = (unsigned long)((a[0])+(a[1]<<8)+(a[2]<<16)+(a[3]<<24));
  printf("[Fancy ftpd]Server data translation address is %s:%d\n",
	 inet_ntoa(ss.client_ip), ntohs(ss.client_port));
}

void connect_to_client(char * arg)
{
  //  char buff1[TELNET_LENGTH];
  char buff2[TELNET_LENGTH];
  char *p1, *p2;
  // p1 = strchr(buff1,'(');
  //p2 = strrchr(buff1, ')');
  //strncpy(buff2, p1+1, p2-p1+1);
  get_port(arg);
	
  int h;
  dtsock = socket(AF_INET, SOCK_STREAM, 0);
  check_error(dtsock, "socket of transfer");
  serverdt.sin_family = AF_INET;
  serverdt.sin_port = ss.client_port;
  serverdt.sin_addr.s_addr = ss.client_ip;
  h = connect(dtsock, (struct sockaddr*)&serverdt, sizeof(serverdt));
  check_error(h, "connect data address");
  printf("[Fancy ftpd]Establish data connect to %s:%d\n",
	 inet_ntoa(serverdt.sin_addr.s_addr), ntohs(serverdt.sin_port));
}

int parse_command(char *cmd)
{
  int len = strlen(cmd);
  int end;
  end = 0;
  while (end<len && cmd[end]!=' ' && cmd[end]!='\r')
    {
      cmd[end] = toupper(cmd[end]);
      end++;
    }
  if(end == 0)
    return 0;
  else if (strncmp(cmd,"PASV",end)==0)
    return 1;
  else if (strncmp(cmd, "CWD", end)==0)
    return 2;
  else if (strncmp(cmd, "QUIT", end)==0)
    return 3;
  else if (strncmp(cmd, "TYPE", end)==0)
    return 4;
  else if (strncmp(cmd, "RETR", end)==0)
    return 5;
  else if (strncmp(cmd, "STOR", end)==0)
    return 6;
  else if (strncmp(cmd, "NOOP", end)==0)
    return 7;
  else if (strncmp(cmd, "HELP", end)==0)
    return 8;
  else if (strncmp(cmd, "PORT", end)==0)
    return 9;
  else if (strncmp(cmd, "PWD", end)==0)
    return 10;
  else if (strncmp(cmd, "LIST", end)==0 || strncmp(cmd, "NLST", end)==0)
    return 11;
  else if (strncmp(cmd, "USER", end)==0)
    return 12;
  else if (strncmp(cmd, "PASS", end)==0)
    return 13;
  else if (strncmp(cmd, "SYST", end)==0)
    return 14;
  else if (strncmp(cmd, "CDUP", end)==0)
    return 15;
  else return 0;
}

void * accept_data_connection(void * arg)
{
  int addrlen = sizeof(serverdt);
  //  struct sockaddr_in temp;
  dtsock = accept(dlsock, (struct sockaddr *) &serverdt, &addrlen);
  check_error(dtsock, "accept");
}

void handle_passive_mode()
{
  int h;
  dlsock = socket(AF_INET, SOCK_STREAM, 0);
  int opt = 1;
  h = setsockopt(dlsock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(int));
  check_error(h, "setsockopt of data listen socket");
  //serverdl.sin_family = AF_INET;
  //serverdl.sin_addr.s_addr = htonl(INADDR_ANY);
  //serverdl.sin_port = htons(current_data_port++);
  int addrlen = sizeof(serverdl);
  h = getsockname(dlsock, (struct sockaddr*)&serverdl, &addrlen);
  check_error(h ,"getsockname");
  serverdl.sin_family = AF_INET;
  inet_aton(LOCAL_IP, &(serverdl.sin_addr));
  //  serverdl.sin_addr.s_addr = htonl(INADDR_ANY);
  do 
    {
      serverdl.sin_port = htons(current_data_port++);
    }
  while (bind(dlsock, (struct sockaddr*)&serverdl, sizeof(serverdl))<0);
  h = listen(dlsock,10);
  check_error(h, "listen");
  pthread_t accept_thread;
  pthread_create(&accept_thread, NULL, accept_data_connection, NULL);
  char rpl_buff[TELNET_LENGTH];
  unsigned long dl_ip = serverdl.sin_addr.s_addr;
  unsigned short dl_port = serverdl.sin_port;
  sprintf(rpl_buff, "227 Entering Passive Mode (%d,%d,%d,%d,%d,%d)",
	  (dl_ip&0xFF), (dl_ip&0x0000FF00)>>8, (dl_ip&0x00FF0000)>>16, dl_ip>>24,
	  dl_port&0xFF,dl_port>>8);
  reply(R227, rpl_buff, asock);
  printf("[Fancy ftpd]%s\n", rpl_buff);
  ss.isPassive = 1;
  h = pthread_join(accept_thread, NULL);
  check_error(h, "pthread_join");
  printf("[Fancy]Establish data transfer connection from %s:%d\n",
	 inet_ntoa(serverdt.sin_addr.s_addr), ntohs(serverdt.sin_port));

}

void * list_dir(void *arg)
{
  //if (!ss.isPassive) 
  //establish_data_connection();
  reply(R150, NULL, asock);
  char pathname[2048];
  strcpy(pathname, ss.path_prefix);
  strcat(pathname, ss.current_dir);
  strcat(pathname, (char*)arg);
  if (pathname[strlen(pathname)-1]!='/')
    strcat(pathname, "/");
  char line_buff[TELNET_LENGTH];
  printf("[Fancy ftpd]Scan dir %s\n", pathname);
  struct dirent **eps;
  int n;
  n = scandir (pathname, &eps, one, alphasort);
  if (n >= 0)
    {
      int cnt;
      struct stat s;
      char pkg_buff[TELNET_LENGTH*10] = {'\0'};
      for (cnt = 0; cnt < n; ++cnt)
	{
	  strcpy(line_buff, pathname);
	  strcat(line_buff, eps[cnt]->d_name);
	  stat(line_buff, &s);
	  char pbuff[32];
	  if (!S_ISREG(s.st_mode) && !S_ISDIR(s.st_mode)) continue;
	  permission(s.st_mode, pbuff);
	  struct passwd *uinfo;
	  struct group *ginfo;
	  uinfo = getpwuid(s.st_uid);
	  ginfo = getgrgid(s.st_gid);
			
	  char tbuff[256];
	  struct tm* t;
	  t = localtime(&s.st_mtime);
	  strftime(tbuff, 1024, "%b %d %k:%M", t);
	  sprintf(line_buff, "%s%3d %s    %s      %12d %s %s\r\n",
		  pbuff, s.st_nlink,
		  uinfo->pw_name, ginfo->gr_name,
		  s.st_size, tbuff,
		  eps[cnt]->d_name);
	  printf("%s", line_buff);
	  strcat(pkg_buff, line_buff);
	}
      send_data(pkg_buff, strlen(pkg_buff), dtsock);
    }
  else
    perror ("Couldn't open the directory");

  close(dtsock);
  ss.isPassive = 0;
  reply(226, "226 Transfer complete.", asock);
  free(arg);
	
}

void * retr_file(void *arg)
{
  char rpl_buff[TELNET_LENGTH];
  //  if (!ss.isPassive) 
  //establish_data_connection();
  char pathname[2048];
  strcpy(pathname, ss.path_prefix);
  if (((char*)arg)[0]=='/')
    strcat(pathname, (char*)arg);
  else
    {
      strcat(pathname, ss.current_dir);
      if (pathname[strlen(pathname)-1]!='/') strcat(pathname,"/");
      strcat(pathname, (char*)arg);
    }
  printf("[Fancy ftpd]Retrive file %s\n", pathname);
  struct stat finfo;
  if (stat(pathname, &finfo)>=0)
    {
      sprintf(rpl_buff, "150 Opening BINARY mode data connection for %s(%d Bytes).",
	      strchr(pathname,'/')+1, finfo.st_size);
      puts(rpl_buff);
      reply(R150, rpl_buff, asock);
    }
  else perror("File not fount.\n");
  FILE *fl;
  fl = fopen(pathname, "r");
  send_file(fl, dtsock);
  fclose(fl);
  free(arg);
  close(dtsock);
  reply(226, "226 Transfer complete.", asock);
}

void * stor_file(void *arg)
{
  char rpl_buff[TELNET_LENGTH];
  //  if (!ss.isPassive) 
    //  establish_data_connection();
  char pathname[2048];
  strcpy(pathname, ss.path_prefix);
  if (((char*)arg)[0]=='/')
    strcat(pathname, (char*)arg);
  else
    {
      strcat(pathname, ss.current_dir);
      if (pathname[strlen(pathname)-1]!='/') strcat(pathname,"/");
      strcat(pathname, (char*)arg);
    }
  printf("[Fancy ftpd]Store file %s\n", pathname);
  sprintf(rpl_buff, "150 Opening BINARY mode data connection for %s.",strchr(pathname,'/')+1);

  reply(R150, rpl_buff, asock);
  
  FILE *fl;
  fl = fopen(pathname, "w");
  receive_file(fl, dtsock);
  fclose(fl);
  free(arg);
  close(dtsock);
  reply(226, "226 Transfer complete.", asock);
}

int check_account()
{
  printf("check account, user[%s], pass[%s]\n", ss.user, ss.pass);
  if (strcmp(ss.user,valid_user)==0 && strcmp(ss.pass, valid_pass)==0) return 1;
  else return 0;
}

void server_pi()
{
  init_server_state();

  char cmd_buff[TELNET_LENGTH];
  char rpl_buff[TELNET_LENGTH];
  char param_buff[TELNET_LENGTH];
  char * param;
  pthread_t trans_thread;

  while(1)
    {
      int len = receive_command(cmd_buff, TELNET_LENGTH, asock);
      cmd_buff[len - 2] = '\0';
      int cmd_id = parse_command(cmd_buff);
      printf("[Fancy ftpd]Receive command <%s>(%d)\n", cmd_buff, cmd_id);
      switch(cmd_id)
	{
	case 0: 
	  reply(R500,NULL,asock);
	  break;//Syntax error
	case 1:
	  handle_passive_mode();
	  break;//PASV
	case 2:
	  parse_parameters(cmd_buff, 1 ,param_buff);
	  if(param_buff[0] == '/')
	    strcpy(ss.current_dir, param_buff);
	  else if((strcmp(param_buff,".")!=0))
	    strcat(ss.current_dir,param_buff);
	  sprintf(rpl_buff,"250 Directory changed to %s", ss.current_dir);
	  reply(R250, rpl_buff,asock);
	  break;//CWD
	case 3:
	  reply(R221, NULL, asock);
	  break;//QUIT
	case 4:
	  parse_parameters(cmd_buff, 1 ,ss.type);
	  sprintf(rpl_buff, "200 Type set to %c.", ss.type[0]);
	  reply(R200, rpl_buff, asock);
	  break;//TYPE
	case 5:
	  param = (char *)malloc(TELNET_LENGTH);
	  parse_parameters(cmd_buff, 1 ,param);
	  pthread_create(& trans_thread, NULL, retr_file, (void *)param);
	  break;//RETR
	case 6:
	  param = (char *)malloc(TELNET_LENGTH);
	  parse_parameters(cmd_buff, 1 ,param);
	  pthread_create(& trans_thread, NULL, stor_file, (void *)param);
	  break;//STOR
	case 7:
	  reply(R200, NULL, asock);
	  break;//NOOP
	case 8:
	  sprintf(rpl_buff, 
		  "214-The following commands are recognized\r\n USER PASS RETR STOR PORT PASV\r\n CWD  CDUP PWD  LIST TYPE STAT\r\n NOOP QUIT\r\n214 [e-mail]"
		  //"214\r\n-blabla\r\nblablabla\r\n214 blabla\r\n"
);
	  reply(R214, rpl_buff, asock);
	  break;//HELP
	case 9:
	  parse_parameters(cmd_buff, 1 ,param_buff);
	  connect_to_client(param_buff);
	  reply(R200,"200 PORT Command Successful.",asock);
	  //reply(R502, NULL, asock);
	  break;//PORT
	case 10:
	  sprintf(rpl_buff,"250 \"%s\" is current directory.", ss.current_dir);
	  reply(R250, rpl_buff, asock);
	  break;//PWD
	case 11:
	  param = (char *)malloc(TELNET_LENGTH);
	  parse_parameters(cmd_buff, 1 ,param);
	  pthread_create(& trans_thread, NULL, list_dir, (void *)param);
	  break;//LIST
	case 12:
	  parse_parameters(cmd_buff, 1 , ss.user);
	  reply(R331,NULL, asock);
	  break;//USER
	case 13:
	  parse_parameters(cmd_buff, 1 , ss.pass);
	  if(check_account())
	    reply(R230,NULL,asock);
	  else
	    reply(R530,NULL,asock);
	  break;//PASS
	case 14:
	  reply(R215,NULL,asock);
	  break;//SYST
	case 15:
	  param = strrchr(ss.current_dir,'/');
	  *(param+1) = '\0';
	  sprintf(rpl_buff, "250 Directory changed to %s", ss.current_dir);
	  reply(R250, rpl_buff,asock);
	  break;//CDUP
	}
      if(cmd_id == 3)
	break;
    }
  close(asock);
}

int main()
{
  lsock = begin_listen();
  current_data_port = LISTEN_PORT + 1;
  while(1)
    {
      current_data_port += 2;
      int client_len ;
      //      struct sockaddr_in client;
      asock = accept(lsock,(struct sockaddr*) &client,&client_len);
      printf("[Fancy ftpd]Connected to %s:%d\n", inet_ntoa(client.sin_addr.s_addr),ntohs(client.sin_port));
      if( fork() == 0 )
	{
	  close(lsock);
	  server_pi();
	  return 0;
	}
      else 
	close( asock );
    }
  return 0;
}