mcs/class/System/System.Net/FtpWebRequest.cs

   1 //
   2 // System.Net.FtpWebRequest.cs
   3 //
   4 // Authors:
   5 //      Carlos Alberto Cortez (calberto.cortez@gmail.com)
   6 //
   7 // (c) Copyright 2006 Novell, Inc. (http://www.novell.com)
   8 //
   9
  10 using System;
  11 using System.IO;
  12 using System.Net.Sockets;
  13 using System.Text;
  14 using System.Threading;
  15 using System.Net.Cache;
  16 using System.Security.Cryptography.X509Certificates;
  17 using System.Net;
  18 using System.Net.Security;
  19 using System.Security.Authentication;
  20
  21 namespace System.Net
  22 {
  23         public sealed class FtpWebRequest : WebRequest
  24         {
  25                 Uri requestUri;
  26                 string file_name; // By now, used for upload
  27                 ServicePoint servicePoint;
  28                 Stream origDataStream;
  29                 Stream dataStream;
  30                 Stream controlStream;
  31                 StreamReader controlReader;
  32                 NetworkCredential credentials;
  33                 IPHostEntry hostEntry;
  34                 IPEndPoint localEndPoint;
  35                 IWebProxy proxy;
  36                 int timeout = 100000;
  37                 int rwTimeout = 300000;
  38                 long offset = 0;
  39                 bool binary = true;
  40                 bool enableSsl = false;
  41                 bool usePassive = true;
  42                 bool keepAlive = false;
  43                 string method = WebRequestMethods.Ftp.DownloadFile;
  44                 string renameTo;
  45                 object locker = new object ();
  46
  47                 RequestState requestState = RequestState.Before;
  48                 FtpAsyncResult asyncResult;
  49                 FtpWebResponse ftpResponse;
  50                 Stream requestStream;
  51                 string initial_path;
  52
  53                 const string ChangeDir = "CWD";
  54                 const string UserCommand = "USER";
  55                 const string PasswordCommand = "PASS";
  56                 const string TypeCommand = "TYPE";
  57                 const string PassiveCommand = "PASV";
  58                 const string PortCommand = "PORT";
  59                 const string AbortCommand = "ABOR";
  60                 const string AuthCommand = "AUTH";
  61                 const string RestCommand = "REST";
  62                 const string RenameFromCommand = "RNFR";
  63                 const string RenameToCommand = "RNTO";
  64                 const string QuitCommand = "QUIT";
  65                 const string EOL = "\r\n"; // Special end of line
  66
  67                 enum RequestState
  68                 {
  69                         Before,
  70                         Scheduled,
  71                         Connecting,
  72                         Authenticating,
  73                         OpeningData,
  74                         TransferInProgress,
  75                         Finished,
  76                         Aborted,
  77                         Error
  78                 }
  79
  80                 // sorted commands
  81                 static readonly string [] supportedCommands = new string [] {
  82                         WebRequestMethods.Ftp.AppendFile, // APPE
  83                         WebRequestMethods.Ftp.DeleteFile, // DELE
  84                         WebRequestMethods.Ftp.ListDirectoryDetails, // LIST
  85                         WebRequestMethods.Ftp.GetDateTimestamp, // MDTM
  86                         WebRequestMethods.Ftp.MakeDirectory, // MKD
  87                         WebRequestMethods.Ftp.ListDirectory, // NLST
  88                         WebRequestMethods.Ftp.PrintWorkingDirectory, // PWD
  89                         WebRequestMethods.Ftp.Rename, // RENAME
  90                         WebRequestMethods.Ftp.DownloadFile, // RETR
  91                         WebRequestMethods.Ftp.RemoveDirectory, // RMD
  92                         WebRequestMethods.Ftp.GetFileSize, // SIZE
  93                         WebRequestMethods.Ftp.UploadFile, // STOR
  94                         WebRequestMethods.Ftp.UploadFileWithUniqueName // STUR
  95                         };
  96
  97                 internal FtpWebRequest (Uri uri)
  98                 {
  99                         this.requestUri = uri;
 100                         this.proxy = GlobalProxySelection.Select;
 101                 }
 102
 103                 static Exception GetMustImplement ()
 104                 {
 105                         return new NotImplementedException ();
 106                 }
 107
 108                 [MonoTODO]
 109                 public X509CertificateCollection ClientCertificates
 110                 {
 111                         get {
 112                                 throw GetMustImplement ();
 113                         }
 114                         set {
 115                                 throw GetMustImplement ();
 116                         }
 117                 }
 118
 119                 [MonoTODO]
 120                 public override string ConnectionGroupName
 121                 {
 122                         get {
 123                                 throw GetMustImplement ();
 124                         }
 125                         set {
 126                                 throw GetMustImplement ();
 127                         }
 128                 }
 129
 130                 public override string ContentType {
 131                         get {
 132                                 throw new NotSupportedException ();
 133                         }
 134                         set {
 135                                 throw new NotSupportedException ();
 136                         }
 137                 }
 138
 139                 public override long ContentLength {
 140                         get {
 141                                 return 0;
 142                         }
 143                         set {
 144                                 // DO nothing
 145                         }
 146                 }
 147
 148                 public long ContentOffset {
 149                         get {
 150                                 return offset;
 151                         }
 152                         set {
 153                                 CheckRequestStarted ();
 154                                 if (value < 0)
 155                                         throw new ArgumentOutOfRangeException ();
 156
 157                                 offset = value;
 158                         }
 159                 }
 160
 161                 public override ICredentials Credentials {
 162                         get {
 163                                 return credentials;
 164                         }
 165                         set {
 166                                 CheckRequestStarted ();
 167                                 if (value == null)
 168                                         throw new ArgumentNullException ();
 169                                 if (!(value is NetworkCredential))
 170                                         throw new ArgumentException ();
 171
 172                                 credentials = value as NetworkCredential;
 173                         }
 174                 }
 175
 176 #if !NET_2_1
 177                 [MonoTODO]
 178                 public static new RequestCachePolicy DefaultCachePolicy
 179                 {
 180                         get {
 181                                 throw GetMustImplement ();
 182                         }
 183                         set {
 184                                 throw GetMustImplement ();
 185                         }
 186                 }
 187 #endif
 188
 189                 public bool EnableSsl {
 190                         get {
 191                                 return enableSsl;
 192                         }
 193                         set {
 194                                 CheckRequestStarted ();
 195                                 enableSsl = value;
 196                         }
 197                 }
 198
 199                 [MonoTODO]
 200                 public override WebHeaderCollection Headers
 201                 {
 202                         get {
 203                                 throw GetMustImplement ();
 204                         }
 205                         set {
 206                                 throw GetMustImplement ();
 207                         }
 208                 }
 209
 210                 [MonoTODO ("We don't support KeepAlive = true")]
 211                 public bool KeepAlive {
 212                         get {
 213                                 return keepAlive;
 214                         }
 215                         set {
 216                                 CheckRequestStarted ();
 217                                 //keepAlive = value;
 218                         }
 219                 }
 220
 221                 public override string Method {
 222                         get {
 223                                 return method;
 224                         }
 225                         set {
 226                                 CheckRequestStarted ();
 227                                 if (value == null)
 228                                         throw new ArgumentNullException ("Method string cannot be null");
 229
 230                                 if (value.Length == 0 || Array.BinarySearch (supportedCommands, value) < 0)
 231                                         throw new ArgumentException ("Method not supported", "value");
 232
 233                                 method = value;
 234                         }
 235                 }
 236
 237                 public override bool PreAuthenticate {
 238                         get {
 239                                 throw new NotSupportedException ();
 240                         }
 241                         set {
 242                                 throw new NotSupportedException ();
 243                         }
 244                 }
 245
 246                 public override IWebProxy Proxy {
 247                         get {
 248                                 return proxy;
 249                         }
 250                         set {
 251                                 CheckRequestStarted ();
 252                                 proxy = value;
 253                         }
 254                 }
 255
 256                 public int ReadWriteTimeout {
 257                         get {
 258                                 return rwTimeout;
 259                         }
 260                         set {
 261                                 CheckRequestStarted ();
 262
 263                                 if (value < - 1)
 264                                         throw new ArgumentOutOfRangeException ();
 265                                 else
 266                                         rwTimeout = value;
 267                         }
 268                 }
 269
 270                 public string RenameTo {
 271                         get {
 272                                 return renameTo;
 273                         }
 274                         set {
 275                                 CheckRequestStarted ();
 276                                 if (value == null || value.Length == 0)
 277                                         throw new ArgumentException ("RenameTo value can't be null or empty", "RenameTo");
 278
 279                                 renameTo = value;
 280                         }
 281                 }
 282
 283                 public override Uri RequestUri {
 284                         get {
 285                                 return requestUri;
 286                         }
 287                 }
 288
 289                 public ServicePoint ServicePoint {
 290                         get {
 291                                 return GetServicePoint ();
 292                         }
 293                 }
 294
 295                 public bool UsePassive {
 296                         get {
 297                                 return usePassive;
 298                         }
 299                         set {
 300                                 CheckRequestStarted ();
 301                                 usePassive = value;
 302                         }
 303                 }
 304
 305                 [MonoTODO]
 306                 public override bool UseDefaultCredentials
 307                 {
 308                         get {
 309                                 throw GetMustImplement ();
 310                         }
 311                         set {
 312                                 throw GetMustImplement ();
 313                         }
 314                 }
 315
 316                 public bool UseBinary {
 317                         get {
 318                                 return binary;
 319                         } set {
 320                                 CheckRequestStarted ();
 321                                 binary = value;
 322                         }
 323                 }
 324
 325                 public override int Timeout {
 326                         get {
 327                                 return timeout;
 328                         }
 329                         set {
 330                                 CheckRequestStarted ();
 331
 332                                 if (value < -1)
 333                                         throw new ArgumentOutOfRangeException ();
 334                                 else
 335                                         timeout = value;
 336                         }
 337                 }
 338
 339                 string DataType {
 340                         get {
 341                                 return binary ? "I" : "A";
 342                         }
 343                 }
 344
 345                 RequestState State {
 346                         get {
 347                                 lock (locker) {
 348                                         return requestState;
 349                                 }
 350                         }
 351
 352                         set {
 353                                 lock (locker) {
 354                                         CheckIfAborted ();
 355                                         CheckFinalState ();
 356                                         requestState = value;
 357                                 }
 358                         }
 359                 }
 360
 361                 public override void Abort () {
 362                         lock (locker) {
 363                                 if (State == RequestState.TransferInProgress) {
 364                                         /*FtpStatus status = */
 365                                         SendCommand (false, AbortCommand);
 366                                 }
 367
 368                                 if (!InFinalState ()) {
 369                                         State = RequestState.Aborted;
 370                                         ftpResponse = new FtpWebResponse (this, requestUri, method, FtpStatusCode.FileActionAborted, "Aborted by request");
 371                                 }
 372                         }
 373                 }
 374
 375                 public override IAsyncResult BeginGetResponse (AsyncCallback callback, object state) {
 376                         if (asyncResult != null && !asyncResult.IsCompleted) {
 377                                 throw new InvalidOperationException ("Cannot re-call BeginGetRequestStream/BeginGetResponse while a previous call is still in progress");
 378                         }
 379
 380                         CheckIfAborted ();
 381
 382                         asyncResult = new FtpAsyncResult (callback, state);
 383
 384                         lock (locker) {
 385                                 if (InFinalState ())
 386                                         asyncResult.SetCompleted (true, ftpResponse);
 387                                 else {
 388                                         if (State == RequestState.Before)
 389                                                 State = RequestState.Scheduled;
 390
 391                                         Thread thread = new Thread (ProcessRequest);
 392                                         thread.Start ();
 393                                 }
 394                         }
 395
 396                         return asyncResult;
 397                 }
 398
 399                 public override WebResponse EndGetResponse (IAsyncResult asyncResult) {
 400                         if (asyncResult == null)
 401                                 throw new ArgumentNullException ("AsyncResult cannot be null!");
 402
 403                         if (!(asyncResult is FtpAsyncResult) || asyncResult != this.asyncResult)
 404                                 throw new ArgumentException ("AsyncResult is from another request!");
 405
 406                         FtpAsyncResult asyncFtpResult = (FtpAsyncResult) asyncResult;
 407                         if (!asyncFtpResult.WaitUntilComplete (timeout, false)) {
 408                                 Abort ();
 409                                 throw new WebException ("Transfer timed out.", WebExceptionStatus.Timeout);
 410                         }
 411
 412                         CheckIfAborted ();
 413
 414                         asyncResult = null;
 415
 416                         if (asyncFtpResult.GotException)
 417                                 throw asyncFtpResult.Exception;
 418
 419                         return asyncFtpResult.Response;
 420                 }
 421
 422                 public override WebResponse GetResponse () {
 423                         IAsyncResult asyncResult = BeginGetResponse (null, null);
 424                         return EndGetResponse (asyncResult);
 425                 }
 426
 427                 public override IAsyncResult BeginGetRequestStream (AsyncCallback callback, object state) {
 428                         if (method != WebRequestMethods.Ftp.UploadFile && method != WebRequestMethods.Ftp.UploadFileWithUniqueName &&
 429                                         method != WebRequestMethods.Ftp.AppendFile)
 430                                 throw new ProtocolViolationException ();
 431
 432                         lock (locker) {
 433                                 CheckIfAborted ();
 434
 435                                 if (State != RequestState.Before)
 436                                         throw new InvalidOperationException ("Cannot re-call BeginGetRequestStream/BeginGetResponse while a previous call is still in progress");
 437
 438                                 State = RequestState.Scheduled;
 439                         }
 440
 441                         asyncResult = new FtpAsyncResult (callback, state);
 442                         Thread thread = new Thread (ProcessRequest);
 443                         thread.Start ();
 444
 445                         return asyncResult;
 446                 }
 447
 448                 public override Stream EndGetRequestStream (IAsyncResult asyncResult) {
 449                         if (asyncResult == null)
 450                                 throw new ArgumentNullException ("asyncResult");
 451
 452                         if (!(asyncResult is FtpAsyncResult))
 453                                 throw new ArgumentException ("asyncResult");
 454
 455                         if (State == RequestState.Aborted) {
 456                                 throw new WebException ("Request aborted", WebExceptionStatus.RequestCanceled);
 457                         }
 458
 459                         if (asyncResult != this.asyncResult)
 460                                 throw new ArgumentException ("AsyncResult is from another request!");
 461
 462                         FtpAsyncResult res = (FtpAsyncResult) asyncResult;
 463
 464                         if (!res.WaitUntilComplete (timeout, false)) {
 465                                 Abort ();
 466                                 throw new WebException ("Request timed out");
 467                         }
 468
 469                         if (res.GotException)
 470                                 throw res.Exception;
 471
 472                         return res.Stream;
 473                 }
 474
 475                 public override Stream GetRequestStream () {
 476                         IAsyncResult asyncResult = BeginGetRequestStream (null, null);
 477                         return EndGetRequestStream (asyncResult);
 478                 }
 479
 480                 ServicePoint GetServicePoint ()
 481                 {
 482                         if (servicePoint == null)
 483                                 servicePoint = ServicePointManager.FindServicePoint (requestUri, proxy);
 484
 485                         return servicePoint;
 486                 }
 487
 488                 // Probably move some code of command connection here
 489                 void ResolveHost ()
 490                 {
 491                         CheckIfAborted ();
 492                         hostEntry = GetServicePoint ().HostEntry;
 493
 494                         if (hostEntry == null) {
 495                                 ftpResponse.UpdateStatus (new FtpStatus(FtpStatusCode.ActionAbortedLocalProcessingError, "Cannot resolve server name"));
 496                                 throw new WebException ("The remote server name could not be resolved: " + requestUri,
 497                                         null, WebExceptionStatus.NameResolutionFailure, ftpResponse);
 498                         }
 499                 }
 500
 501                 void ProcessRequest () {
 502
 503                         if (State == RequestState.Scheduled) {
 504                                 ftpResponse = new FtpWebResponse (this, requestUri, method, keepAlive);
 505
 506                                 try {
 507                                         ProcessMethod ();
 508                                         //State = RequestState.Finished;
 509                                         //finalResponse = ftpResponse;
 510                                         asyncResult.SetCompleted (false, ftpResponse);
 511                                 }
 512                                 catch (Exception e) {
 513                                         if (!GetServicePoint ().UsesProxy)
 514                                                 State = RequestState.Error;
 515                                         SetCompleteWithError (e);
 516                                 }
 517                         }
 518                         else {
 519                                 if (InProgress ()) {
 520                                         FtpStatus status = GetResponseStatus ();
 521
 522                                         ftpResponse.UpdateStatus (status);
 523
 524                                         if (ftpResponse.IsFinal ()) {
 525                                                 State = RequestState.Finished;
 526                                         }
 527                                 }
 528
 529                                 asyncResult.SetCompleted (false, ftpResponse);
 530                         }
 531                 }
 532
 533                 void SetType ()
 534                 {
 535                         if (binary) {
 536                                 FtpStatus status = SendCommand (TypeCommand, DataType);
 537                                 if ((int) status.StatusCode < 200 || (int) status.StatusCode >= 300)
 538                                         throw CreateExceptionFromResponse (status);
 539                         }
 540                 }
 541
 542                 string GetRemoteFolderPath (Uri uri)
 543                 {
 544                         string result;
 545                         string local_path = Uri.UnescapeDataString (uri.LocalPath);
 546                         if (initial_path == null || initial_path == "/") {
 547                                 result = local_path;
 548                         } else {
 549                                 if (local_path [0] == '/')
 550                                         local_path = local_path.Substring (1);
 551
 552                                 Uri initial = new Uri ("ftp://dummy-host" + initial_path);
 553                                 result = new Uri (initial, local_path).LocalPath;
 554                         }
 555
 556                         int last = result.LastIndexOf ('/');
 557                         if (last == -1)
 558                                 return null;
 559
 560                         return result.Substring (0, last + 1);
 561                 }
 562
 563                 void CWDAndSetFileName (Uri uri)
 564                 {
 565                         string remote_folder = GetRemoteFolderPath (uri);
 566                         FtpStatus status;
 567                         if (remote_folder != null) {
 568                                 status = SendCommand (ChangeDir, remote_folder);
 569                                 if ((int) status.StatusCode < 200 || (int) status.StatusCode >= 300)
 570                                         throw CreateExceptionFromResponse (status);
 571
 572                                 int last = uri.LocalPath.LastIndexOf ('/');
 573                                 if (last >= 0) {
 574                                         file_name = Uri.UnescapeDataString (uri.LocalPath.Substring (last + 1));
 575                                 }
 576                         }
 577                 }
 578
 579                 void ProcessMethod ()
 580                 {
 581                         ServicePoint sp = GetServicePoint ();
 582                         if (sp.UsesProxy) {
 583                                 if (method != WebRequestMethods.Ftp.DownloadFile)
 584                                         throw new NotSupportedException ("FTP+proxy only supports RETR");
 585
 586                                 HttpWebRequest req = (HttpWebRequest) WebRequest.Create (proxy.GetProxy (requestUri));
 587                                 req.Address = requestUri;
 588                                 requestState = RequestState.Finished;
 589                                 WebResponse response = req.GetResponse ();
 590                                 ftpResponse.Stream = new FtpDataStream (this, response.GetResponseStream (), true);
 591                                 ftpResponse.StatusCode = FtpStatusCode.CommandOK;
 592                                 return;
 593                         }
 594                         State = RequestState.Connecting;
 595
 596                         ResolveHost ();
 597
 598                         OpenControlConnection ();
 599                         CWDAndSetFileName (requestUri);
 600                         SetType ();
 601
 602                         switch (method) {
 603                         // Open data connection and receive data
 604                         case WebRequestMethods.Ftp.DownloadFile:
 605                         case WebRequestMethods.Ftp.ListDirectory:
 606                         case WebRequestMethods.Ftp.ListDirectoryDetails:
 607                                 DownloadData ();
 608                                 break;
 609                         // Open data connection and send data
 610                         case WebRequestMethods.Ftp.AppendFile:
 611                         case WebRequestMethods.Ftp.UploadFile:
 612                         case WebRequestMethods.Ftp.UploadFileWithUniqueName:
 613                                 UploadData ();
 614                                 break;
 615                         // Get info from control connection
 616                         case WebRequestMethods.Ftp.GetFileSize:
 617                         case WebRequestMethods.Ftp.GetDateTimestamp:
 618                         case WebRequestMethods.Ftp.PrintWorkingDirectory:
 619                         case WebRequestMethods.Ftp.MakeDirectory:
 620                         case WebRequestMethods.Ftp.Rename:
 621                         case WebRequestMethods.Ftp.DeleteFile:
 622                                 ProcessSimpleMethod ();
 623                                 break;
 624                         default: // What to do here?
 625                                 throw new Exception (String.Format ("Support for command {0} not implemented yet", method));
 626                         }
 627
 628                         CheckIfAborted ();
 629                 }
 630
 631                 private void CloseControlConnection () {
 632                         if (controlStream != null) {
 633                                 SendCommand (QuitCommand);
 634                                 controlStream.Close ();
 635                                 controlStream = null;
 636                         }
 637                 }
 638
 639                 internal void CloseDataConnection () {
 640                         if(origDataStream != null) {
 641                                 origDataStream.Close ();
 642                                 origDataStream = null;
 643                         }
 644                 }
 645
 646                 private void CloseConnection () {
 647                         CloseControlConnection ();
 648                         CloseDataConnection ();
 649                 }
 650
 651                 void ProcessSimpleMethod ()
 652                 {
 653                         State = RequestState.TransferInProgress;
 654
 655                         FtpStatus status;
 656
 657                         if (method == WebRequestMethods.Ftp.PrintWorkingDirectory)
 658                                 method = "PWD";
 659
 660                         if (method == WebRequestMethods.Ftp.Rename)
 661                                 method = RenameFromCommand;
 662
 663                         status = SendCommand (method, file_name);
 664
 665                         ftpResponse.Stream = Stream.Null;
 666
 667                         string desc = status.StatusDescription;
 668
 669                         switch (method) {
 670                         case WebRequestMethods.Ftp.GetFileSize: {
 671                                         if (status.StatusCode != FtpStatusCode.FileStatus)
 672                                                 throw CreateExceptionFromResponse (status);
 673
 674                                         int i, len;
 675                                         long size;
 676                                         for (i = 4, len = 0; i < desc.Length && Char.IsDigit (desc [i]); i++, len++)
 677                                                 ;
 678
 679                                         if (len == 0)
 680                                                 throw new WebException ("Bad format for server response in " + method);
 681
 682                                         if (!Int64.TryParse (desc.Substring (4, len), out size))
 683                                                 throw new WebException ("Bad format for server response in " + method);
 684
 685                                         ftpResponse.contentLength = size;
 686                                 }
 687                                 break;
 688                         case WebRequestMethods.Ftp.GetDateTimestamp:
 689                                 if (status.StatusCode != FtpStatusCode.FileStatus)
 690                                         throw CreateExceptionFromResponse (status);
 691                                 ftpResponse.LastModified = DateTime.ParseExact (desc.Substring (4), "yyyyMMddHHmmss", null);
 692                                 break;
 693                         case WebRequestMethods.Ftp.MakeDirectory:
 694                                 if (status.StatusCode != FtpStatusCode.PathnameCreated)
 695                                         throw CreateExceptionFromResponse (status);
 696                                 break;
 697                         case ChangeDir:
 698                                 method = WebRequestMethods.Ftp.PrintWorkingDirectory;
 699
 700                                 if (status.StatusCode != FtpStatusCode.FileActionOK)
 701                                         throw CreateExceptionFromResponse (status);
 702
 703                                 status = SendCommand (method);
 704
 705                                 if (status.StatusCode != FtpStatusCode.PathnameCreated)
 706                                         throw CreateExceptionFromResponse (status);
 707                                 break;
 708                         case RenameFromCommand:
 709                                 method = WebRequestMethods.Ftp.Rename;
 710                                 if (status.StatusCode != FtpStatusCode.FileCommandPending)
 711                                         throw CreateExceptionFromResponse (status);
 712                                 // Pass an empty string if RenameTo wasn't specified
 713                                 status = SendCommand (RenameToCommand, renameTo != null ? renameTo : String.Empty);
 714                                 if (status.StatusCode != FtpStatusCode.FileActionOK)
 715                                         throw CreateExceptionFromResponse (status);
 716                                 break;
 717                         case WebRequestMethods.Ftp.DeleteFile:
 718                                 if (status.StatusCode != FtpStatusCode.FileActionOK)  {
 719                                         throw CreateExceptionFromResponse (status);
 720                                 }
 721                                 break;
 722                         }
 723
 724                         State = RequestState.Finished;
 725                 }
 726
 727                 void UploadData ()
 728                 {
 729                         State = RequestState.OpeningData;
 730
 731                         OpenDataConnection ();
 732
 733                         State = RequestState.TransferInProgress;
 734                         requestStream = new FtpDataStream (this, dataStream, false);
 735                         asyncResult.Stream = requestStream;
 736                 }
 737
 738                 void DownloadData ()
 739                 {
 740                         State = RequestState.OpeningData;
 741
 742                         OpenDataConnection ();
 743
 744                         State = RequestState.TransferInProgress;
 745                         ftpResponse.Stream = new FtpDataStream (this, dataStream, true);
 746                 }
 747
 748                 void CheckRequestStarted ()
 749                 {
 750                         if (State != RequestState.Before)
 751                                 throw new InvalidOperationException ("There is a request currently in progress");
 752                 }
 753
 754                 void OpenControlConnection ()
 755                 {
 756                         Exception exception = null;
 757                         Socket sock = null;
 758                         foreach (IPAddress address in hostEntry.AddressList) {
 759                                 sock = new Socket (address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
 760
 761                                 IPEndPoint remote = new IPEndPoint (address, requestUri.Port);
 762
 763                                 if (!ServicePoint.CallEndPointDelegate (sock, remote)) {
 764                                         sock.Close ();
 765                                         sock = null;
 766                                 } else {
 767                                         try {
 768                                                 sock.Connect (remote);
 769                                                 localEndPoint = (IPEndPoint) sock.LocalEndPoint;
 770                                                 break;
 771                                         } catch (SocketException exc) {
 772                                                 exception = exc;
 773                                                 sock.Close ();
 774                                                 sock = null;
 775                                         }
 776                                 }
 777                         }
 778
 779                         // Couldn't connect to any address
 780                         if (sock == null)
 781                                 throw new WebException ("Unable to connect to remote server", exception,
 782                                                 WebExceptionStatus.UnknownError, ftpResponse);
 783
 784                         controlStream = new NetworkStream (sock);
 785                         controlReader = new StreamReader (controlStream, Encoding.ASCII);
 786
 787                         State = RequestState.Authenticating;
 788
 789                         Authenticate ();
 790                         FtpStatus status = SendCommand ("OPTS", "utf8", "on");
 791                         // ignore status for OPTS
 792                         status = SendCommand (WebRequestMethods.Ftp.PrintWorkingDirectory);
 793                         initial_path = GetInitialPath (status);
 794                 }
 795
 796                 static string GetInitialPath (FtpStatus status)
 797                 {
 798                         int s = (int) status.StatusCode;
 799                         if (s < 200 || s > 300 || status.StatusDescription.Length <= 4)
 800                                 throw new WebException ("Error getting current directory: " + status.StatusDescription, null,
 801                                                 WebExceptionStatus.UnknownError, null);
 802
 803                         string msg = status.StatusDescription.Substring (4);
 804                         if (msg [0] == '"') {
 805                                 int next_quote = msg.IndexOf ('\"', 1);
 806                                 if (next_quote == -1)
 807                                         throw new WebException ("Error getting current directory: PWD -> " + status.StatusDescription, null,
 808                                                                 WebExceptionStatus.UnknownError, null);
 809
 810                                 msg = msg.Substring (1, next_quote - 1);
 811                         }
 812
 813                         if (!msg.EndsWith ("/"))
 814                                 msg += "/";
 815                         return msg;
 816                 }
 817
 818                 // Probably we could do better having here a regex
 819                 Socket SetupPassiveConnection (string statusDescription)
 820                 {
 821                         // Current response string
 822                         string response = statusDescription;
 823                         if (response.Length < 4)
 824                                 throw new WebException ("Cannot open passive data connection");
 825
 826                         // Look for first digit after code
 827                         int i;
 828                         for (i = 3; i < response.Length && !Char.IsDigit (response [i]); i++)
 829                                 ;
 830                         if (i >= response.Length)
 831                                 throw new WebException ("Cannot open passive data connection");
 832
 833                         // Get six elements
 834                         string [] digits = response.Substring (i).Split (new char [] {','}, 6);
 835                         if (digits.Length != 6)
 836                                 throw new WebException ("Cannot open passive data connection");
 837
 838                         // Clean non-digits at the end of last element
 839                         int j;
 840                         for (j = digits [5].Length - 1; j >= 0 && !Char.IsDigit (digits [5][j]); j--)
 841                                 ;
 842                         if (j < 0)
 843                                 throw new WebException ("Cannot open passive data connection");
 844
 845                         digits [5] = digits [5].Substring (0, j + 1);
 846
 847                         IPAddress ip;
 848                         try {
 849                                 ip = IPAddress.Parse (String.Join (".", digits, 0, 4));
 850                         } catch (FormatException) {
 851                                 throw new WebException ("Cannot open passive data connection");
 852                         }
 853
 854                         // Get the port
 855                         int p1, p2, port;
 856                         if (!Int32.TryParse (digits [4], out p1) || !Int32.TryParse (digits [5], out p2))
 857                                 throw new WebException ("Cannot open passive data connection");
 858
 859                         port = (p1 << 8) + p2; // p1 * 256 + p2
 860                         //port = p1 * 256 + p2;
 861                         if (port < IPEndPoint.MinPort || port > IPEndPoint.MaxPort)
 862                                 throw new WebException ("Cannot open passive data connection");
 863
 864                         IPEndPoint ep = new IPEndPoint (ip, port);
 865                         Socket sock = new Socket (ep.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
 866                         try {
 867                                 sock.Connect (ep);
 868                         } catch (SocketException) {
 869                                 sock.Close ();
 870                                 throw new WebException ("Cannot open passive data connection");
 871                         }
 872
 873                         return sock;
 874                 }
 875
 876                 Exception CreateExceptionFromResponse (FtpStatus status)
 877                 {
 878                         FtpWebResponse ftpResponse = new FtpWebResponse (this, requestUri, method, status);
 879
 880                         WebException exc = new WebException ("Server returned an error: " + status.StatusDescription,
 881                                 null, WebExceptionStatus.ProtocolError, ftpResponse);
 882                         return exc;
 883                 }
 884
 885                 // Here we could also get a server error, so be cautious
 886                 internal void SetTransferCompleted ()
 887                 {
 888                         if (InFinalState ())
 889                                 return;
 890
 891                         State = RequestState.Finished;
 892                         FtpStatus status = GetResponseStatus ();
 893                         ftpResponse.UpdateStatus (status);
 894                         if(!keepAlive)
 895                                 CloseConnection ();
 896                 }
 897
 898                 internal void OperationCompleted ()
 899                 {
 900                         if(!keepAlive)
 901                                 CloseConnection ();
 902                 }
 903
 904                 void SetCompleteWithError (Exception exc)
 905                 {
 906                         if (asyncResult != null) {
 907                                 asyncResult.SetCompleted (false, exc);
 908                         }
 909                 }
 910
 911                 Socket InitDataConnection ()
 912                 {
 913                         FtpStatus status;
 914
 915                         if (usePassive) {
 916                                 status = SendCommand (PassiveCommand);
 917                                 if (status.StatusCode != FtpStatusCode.EnteringPassive) {
 918                                         throw CreateExceptionFromResponse (status);
 919                                 }
 920
 921                                 return SetupPassiveConnection (status.StatusDescription);
 922                         }
 923
 924                         // Open a socket to listen the server's connection
 925                         Socket sock = new Socket (AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
 926                         try {
 927                                 sock.Bind (new IPEndPoint (localEndPoint.Address, 0));
 928                                 sock.Listen (1); // We only expect a connection from server
 929
 930                         } catch (SocketException e) {
 931                                 sock.Close ();
 932
 933                                 throw new WebException ("Couldn't open listening socket on client", e);
 934                         }
 935
 936                         IPEndPoint ep = (IPEndPoint) sock.LocalEndPoint;
 937                         string ipString = ep.Address.ToString ().Replace ('.', ',');
 938                         int h1 = ep.Port >> 8; // ep.Port / 256
 939                         int h2 = ep.Port % 256;
 940
 941                         string portParam = ipString + "," + h1 + "," + h2;
 942                         status = SendCommand (PortCommand, portParam);
 943
 944                         if (status.StatusCode != FtpStatusCode.CommandOK) {
 945                                 sock.Close ();
 946                                 throw (CreateExceptionFromResponse (status));
 947                         }
 948
 949                         return sock;
 950                 }
 951
 952                 void OpenDataConnection ()
 953                 {
 954                         FtpStatus status;
 955
 956                         Socket s = InitDataConnection ();
 957
 958                         // Handle content offset
 959                         if (offset > 0) {
 960                                 status = SendCommand (RestCommand, offset.ToString ());
 961                                 if (status.StatusCode != FtpStatusCode.FileCommandPending)
 962                                         throw CreateExceptionFromResponse (status);
 963                         }
 964
 965                         if (method != WebRequestMethods.Ftp.ListDirectory && method != WebRequestMethods.Ftp.ListDirectoryDetails &&
 966                             method != WebRequestMethods.Ftp.UploadFileWithUniqueName) {
 967                                 status = SendCommand (method, file_name);
 968                         } else {
 969                                 status = SendCommand (method);
 970                         }
 971
 972                         if (status.StatusCode != FtpStatusCode.OpeningData && status.StatusCode != FtpStatusCode.DataAlreadyOpen)
 973                                 throw CreateExceptionFromResponse (status);
 974
 975                         if (usePassive) {
 976                                 origDataStream = new NetworkStream (s, true);
 977                                 dataStream = origDataStream;
 978                                 if (EnableSsl)
 979                                         ChangeToSSLSocket (ref dataStream);
 980                         }
 981                         else {
 982
 983                                 // Active connection (use Socket.Blocking to true)
 984                                 Socket incoming = null;
 985                                 try {
 986                                         incoming = s.Accept ();
 987                                 }
 988                                 catch (SocketException) {
 989                                         s.Close ();
 990                                         if (incoming != null)
 991                                                 incoming.Close ();
 992
 993                                         throw new ProtocolViolationException ("Server commited a protocol violation.");
 994                                 }
 995
 996                                 s.Close ();
 997                                 origDataStream = new NetworkStream (incoming, true);
 998                                 dataStream = origDataStream;
 999                                 if (EnableSsl)
1000                                         ChangeToSSLSocket (ref dataStream);
1001                         }
1002
1003                         ftpResponse.UpdateStatus (status);
1004                 }
1005
1006                 void Authenticate ()
1007                 {
1008                         string username = null;
1009                         string password = null;
1010                         string domain = null;
1011
1012                         if (credentials != null) {
1013                                 username = credentials.UserName;
1014                                 password = credentials.Password;
1015                                 domain = credentials.Domain;
1016                         }
1017
1018                         if (username == null)
1019                                 username = "anonymous";
1020                         if (password == null)
1021                                 password = "@anonymous";
1022                         if (!string.IsNullOrEmpty (domain))
1023                                 username = domain + '\\' + username;
1024
1025                         // Connect to server and get banner message
1026                         FtpStatus status = GetResponseStatus ();
1027                         ftpResponse.BannerMessage = status.StatusDescription;
1028
1029                         if (EnableSsl) {
1030                                 InitiateSecureConnection (ref controlStream);
1031                                 controlReader = new StreamReader (controlStream, Encoding.ASCII);
1032                                 status = SendCommand ("PBSZ", "0");
1033                                 int st = (int) status.StatusCode;
1034                                 if (st < 200 || st >= 300)
1035                                         throw CreateExceptionFromResponse (status);
1036                                 // TODO: what if "PROT P" is denied by the server? What does MS do?
1037                                 status = SendCommand ("PROT", "P");
1038                                 st = (int) status.StatusCode;
1039                                 if (st < 200 || st >= 300)
1040                                         throw CreateExceptionFromResponse (status);
1041
1042                                 status = new FtpStatus (FtpStatusCode.SendUserCommand, "");
1043                         }
1044
1045                         if (status.StatusCode != FtpStatusCode.SendUserCommand)
1046                                 throw CreateExceptionFromResponse (status);
1047
1048                         status = SendCommand (UserCommand, username);
1049
1050                         switch (status.StatusCode) {
1051                         case FtpStatusCode.SendPasswordCommand:
1052                                 status = SendCommand (PasswordCommand, password);
1053                                 if (status.StatusCode != FtpStatusCode.LoggedInProceed)
1054                                         throw CreateExceptionFromResponse (status);
1055                                 break;
1056                         case FtpStatusCode.LoggedInProceed:
1057                                 break;
1058                         default:
1059                                 throw CreateExceptionFromResponse (status);
1060                         }
1061
1062                         ftpResponse.WelcomeMessage = status.StatusDescription;
1063                         ftpResponse.UpdateStatus (status);
1064                 }
1065
1066                 FtpStatus SendCommand (string command, params string [] parameters) {
1067                         return SendCommand (true, command, parameters);
1068                 }
1069
1070                 FtpStatus SendCommand (bool waitResponse, string command, params string [] parameters)
1071                 {
1072                         byte [] cmd;
1073                         string commandString = command;
1074                         if (parameters.Length > 0)
1075                                 commandString += " " + String.Join (" ", parameters);
1076
1077                         commandString += EOL;
1078                         cmd = Encoding.ASCII.GetBytes (commandString);
1079                         try {
1080                                 controlStream.Write (cmd, 0, cmd.Length);
1081                         } catch (IOException) {
1082                                 //controlStream.Close ();
1083                                 return new FtpStatus(FtpStatusCode.ServiceNotAvailable, "Write failed");
1084                         }
1085
1086                         if(!waitResponse)
1087                                 return null;
1088
1089                         FtpStatus result = GetResponseStatus ();
1090                         if (ftpResponse != null)
1091                                 ftpResponse.UpdateStatus (result);
1092                         return result;
1093                 }
1094
1095                 internal static FtpStatus ServiceNotAvailable ()
1096                 {
1097                         return new FtpStatus (FtpStatusCode.ServiceNotAvailable, Locale.GetText ("Invalid response from server"));
1098                 }
1099
1100                 internal FtpStatus GetResponseStatus ()
1101                 {
1102                         while (true) {
1103                                 string response = null;
1104
1105                                 try {
1106                                         response = controlReader.ReadLine ();
1107                                 } catch (IOException) {
1108                                 }
1109
1110                                 if (response == null || response.Length < 3)
1111                                         return ServiceNotAvailable ();
1112
1113                                 int code;
1114                                 if (!Int32.TryParse (response.Substring (0, 3), out code))
1115                                         return ServiceNotAvailable ();
1116
1117                                 if (response.Length > 3 && response [3] == '-'){
1118                                         string line = null;
1119                                         string find = code.ToString() + ' ';
1120                                         while (true){
1121                                                 line = null;
1122                                                 try {
1123                                                         line = controlReader.ReadLine();
1124                                                 } catch (IOException) {
1125                                                 }
1126                                                 if (line == null)
1127                                                         return ServiceNotAvailable ();
1128
1129                                                 response += Environment.NewLine + line;
1130
1131                                                 if (line.StartsWith(find, StringComparison.Ordinal))
1132                                                         break;
1133                                         }
1134                                 }
1135                                 return new FtpStatus ((FtpStatusCode) code, response);
1136                         }
1137                 }
1138
1139                 private void InitiateSecureConnection (ref Stream stream) {
1140                         FtpStatus status = SendCommand (AuthCommand, "TLS");
1141                         if (status.StatusCode != FtpStatusCode.ServerWantsSecureSession)
1142                                 throw CreateExceptionFromResponse (status);
1143
1144                         ChangeToSSLSocket (ref stream);
1145                 }
1146
1147 #if SECURITY_DEP
1148                 RemoteCertificateValidationCallback callback = delegate (object sender,
1149                                                                          X509Certificate certificate,
1150                                                                          X509Chain chain,
1151                                                                          SslPolicyErrors sslPolicyErrors) {
1152                         // honor any exciting callback defined on ServicePointManager
1153                         if (ServicePointManager.ServerCertificateValidationCallback != null)
1154                                 return ServicePointManager.ServerCertificateValidationCallback (sender, certificate, chain, sslPolicyErrors);
1155                         // otherwise provide our own
1156                         if (sslPolicyErrors != SslPolicyErrors.None)
1157                                 throw new InvalidOperationException ("SSL authentication error: " + sslPolicyErrors);
1158                         return true;
1159                         };
1160 #endif
1161
1162                 internal bool ChangeToSSLSocket (ref Stream stream) {
1163 #if TARGET_JVM
1164                         stream.ChangeToSSLSocket ();
1165                         return true;
1166 #elif SECURITY_DEP
1167                         SslStream sslStream = new SslStream (stream, true, callback, null);
1168                         //sslStream.AuthenticateAsClient (Host, this.ClientCertificates, SslProtocols.Default, false);
1169                         //TODO: client certificates
1170                         sslStream.AuthenticateAsClient (requestUri.Host, null, SslProtocols.Default, false);
1171                         stream = sslStream;
1172                         return true;
1173 #else
1174                         throw new NotImplementedException ();
1175 #endif
1176                 }
1177
1178                 bool InFinalState () {
1179                         return (State == RequestState.Aborted || State == RequestState.Error || State == RequestState.Finished);
1180                 }
1181
1182                 bool InProgress () {
1183                         return (State != RequestState.Before && !InFinalState ());
1184                 }
1185
1186                 internal void CheckIfAborted () {
1187                         if (State == RequestState.Aborted)
1188                                 throw new WebException ("Request aborted", WebExceptionStatus.RequestCanceled);
1189                 }
1190
1191                 void CheckFinalState () {
1192                         if (InFinalState ())
1193                                 throw new InvalidOperationException ("Cannot change final state");
1194                 }
1195         }
1196 }
1197
1198