net/ftp/ftp_network_transaction.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/ftp/ftp_network_transaction.h"
   6
   7 #include "base/bind.h"
   8 #include "base/bind_helpers.h"
   9 #include "base/compiler_specific.h"
  10 #include "base/metrics/histogram.h"
  11 #include "base/strings/string_number_conversions.h"
  12 #include "base/strings/string_util.h"
  13 #include "base/strings/string_split.h"
  14 #include "base/strings/utf_string_conversions.h"
  15 #include "base/values.h"
  16 #include "net/base/address_list.h"
  17 #include "net/base/connection_type_histograms.h"
  18 #include "net/base/escape.h"
  19 #include "net/base/net_errors.h"
  20 #include "net/base/net_log.h"
  21 #include "net/base/net_util.h"
  22 #include "net/ftp/ftp_network_session.h"
  23 #include "net/ftp/ftp_request_info.h"
  24 #include "net/ftp/ftp_util.h"
  25 #include "net/socket/client_socket_factory.h"
  26 #include "net/socket/stream_socket.h"
  27
  28 const char kCRLF[] = "\r\n";
  29
  30 const int kCtrlBufLen = 1024;
  31
  32 namespace {
  33
  34 // Returns true if |input| can be safely used as a part of FTP command.
  35 bool IsValidFTPCommandString(const std::string& input) {
  36   // RFC 959 only allows ASCII strings, but at least Firefox can send non-ASCII
  37   // characters in the command if the request path contains them. To be
  38   // compatible, we do the same and allow non-ASCII characters in a command.
  39
  40   // Protect agains newline injection attack.
  41   if (input.find_first_of("\r\n") != std::string::npos)
  42     return false;
  43
  44   return true;
  45 }
  46
  47 enum ErrorClass {
  48   // The requested action was initiated. The client should expect another
  49   // reply before issuing the next command.
  50   ERROR_CLASS_INITIATED,
  51
  52   // The requested action has been successfully completed.
  53   ERROR_CLASS_OK,
  54
  55   // The command has been accepted, but to complete the operation, more
  56   // information must be sent by the client.
  57   ERROR_CLASS_INFO_NEEDED,
  58
  59   // The command was not accepted and the requested action did not take place.
  60   // This condition is temporary, and the client is encouraged to restart the
  61   // command sequence.
  62   ERROR_CLASS_TRANSIENT_ERROR,
  63
  64   // The command was not accepted and the requested action did not take place.
  65   // This condition is rather permanent, and the client is discouraged from
  66   // repeating the exact request.
  67   ERROR_CLASS_PERMANENT_ERROR,
  68 };
  69
  70 // Returns the error class for given response code. Caller should ensure
  71 // that |response_code| is in range 100-599.
  72 ErrorClass GetErrorClass(int response_code) {
  73   if (response_code >= 100 && response_code <= 199)
  74     return ERROR_CLASS_INITIATED;
  75
  76   if (response_code >= 200 && response_code <= 299)
  77     return ERROR_CLASS_OK;
  78
  79   if (response_code >= 300 && response_code <= 399)
  80     return ERROR_CLASS_INFO_NEEDED;
  81
  82   if (response_code >= 400 && response_code <= 499)
  83     return ERROR_CLASS_TRANSIENT_ERROR;
  84
  85   if (response_code >= 500 && response_code <= 599)
  86     return ERROR_CLASS_PERMANENT_ERROR;
  87
  88   // We should not be called on invalid error codes.
  89   NOTREACHED() << response_code;
  90   return ERROR_CLASS_PERMANENT_ERROR;
  91 }
  92
  93 // Returns network error code for received FTP |response_code|.
  94 int GetNetErrorCodeForFtpResponseCode(int response_code) {
  95   switch (response_code) {
  96     case 421:
  97       return net::ERR_FTP_SERVICE_UNAVAILABLE;
  98     case 426:
  99       return net::ERR_FTP_TRANSFER_ABORTED;
 100     case 450:
 101       return net::ERR_FTP_FILE_BUSY;
 102     case 500:
 103     case 501:
 104       return net::ERR_FTP_SYNTAX_ERROR;
 105     case 502:
 106     case 504:
 107       return net::ERR_FTP_COMMAND_NOT_SUPPORTED;
 108     case 503:
 109       return net::ERR_FTP_BAD_COMMAND_SEQUENCE;
 110     default:
 111       return net::ERR_FTP_FAILED;
 112   }
 113 }
 114
 115 // From RFC 2428 Section 3:
 116 //   The text returned in response to the EPSV command MUST be:
 117 //     <some text> (<d><d><d><tcp-port><d>)
 118 //   <d> is a delimiter character, ideally to be |
 119 bool ExtractPortFromEPSVResponse(const net::FtpCtrlResponse& response,
 120                                  int* port) {
 121   if (response.lines.size() != 1)
 122     return false;
 123   const char* ptr = response.lines[0].c_str();
 124   while (*ptr && *ptr != '(')
 125     ++ptr;
 126   if (!*ptr)
 127     return false;
 128   char sep = *(++ptr);
 129   if (!sep || isdigit(sep) || *(++ptr) != sep || *(++ptr) != sep)
 130     return false;
 131   if (!isdigit(*(++ptr)))
 132     return false;
 133   *port = *ptr - '0';
 134   while (isdigit(*(++ptr))) {
 135     *port *= 10;
 136     *port += *ptr - '0';
 137   }
 138   if (*ptr != sep)
 139     return false;
 140
 141   return true;
 142 }
 143
 144 // There are two way we can receive IP address and port.
 145 // (127,0,0,1,23,21) IP address and port encapsulated in ().
 146 // 127,0,0,1,23,21  IP address and port without ().
 147 //
 148 // See RFC 959, Section 4.1.2
 149 bool ExtractPortFromPASVResponse(const net::FtpCtrlResponse& response,
 150                                  int* port) {
 151   if (response.lines.size() != 1)
 152     return false;
 153
 154   std::string line(response.lines[0]);
 155   if (!base::IsStringASCII(line))
 156     return false;
 157   if (line.length() < 2)
 158     return false;
 159
 160   size_t paren_pos = line.find('(');
 161   if (paren_pos == std::string::npos) {
 162     // Find the first comma and use it to locate the beginning
 163     // of the response data.
 164     size_t comma_pos = line.find(',');
 165     if (comma_pos == std::string::npos)
 166       return false;
 167
 168     size_t space_pos = line.rfind(' ', comma_pos);
 169     if (space_pos != std::string::npos)
 170       line = line.substr(space_pos + 1);
 171   } else {
 172     // Remove the parentheses and use the text inside them.
 173     size_t closing_paren_pos = line.rfind(')');
 174     if (closing_paren_pos == std::string::npos)
 175       return false;
 176     if (closing_paren_pos <= paren_pos)
 177       return false;
 178
 179     line = line.substr(paren_pos + 1, closing_paren_pos - paren_pos - 1);
 180   }
 181
 182   // Split the line into comma-separated pieces and extract
 183   // the last two.
 184   std::vector<std::string> pieces;
 185   base::SplitString(line, ',', &pieces);
 186   if (pieces.size() != 6)
 187     return false;
 188
 189   // Ignore the IP address supplied in the response. We are always going
 190   // to connect back to the same server to prevent FTP PASV port scanning.
 191   int p0, p1;
 192   if (!base::StringToInt(pieces[4], &p0))
 193     return false;
 194   if (!base::StringToInt(pieces[5], &p1))
 195     return false;
 196   *port = (p0 << 8) + p1;
 197
 198   return true;
 199 }
 200
 201 }  // namespace
 202
 203 namespace net {
 204
 205 FtpNetworkTransaction::FtpNetworkTransaction(
 206     FtpNetworkSession* session,
 207     ClientSocketFactory* socket_factory)
 208     : command_sent_(COMMAND_NONE),
 209       io_callback_(base::Bind(&FtpNetworkTransaction::OnIOComplete,
 210                               base::Unretained(this))),
 211       session_(session),
 212       request_(NULL),
 213       resolver_(session->host_resolver()),
 214       read_ctrl_buf_(new IOBuffer(kCtrlBufLen)),
 215       read_data_buf_len_(0),
 216       last_error_(OK),
 217       system_type_(SYSTEM_TYPE_UNKNOWN),
 218       // Use image (binary) transfer by default. It should always work,
 219       // whereas the ascii transfer may damage binary data.
 220       data_type_(DATA_TYPE_IMAGE),
 221       resource_type_(RESOURCE_TYPE_UNKNOWN),
 222       use_epsv_(true),
 223       data_connection_port_(0),
 224       socket_factory_(socket_factory),
 225       next_state_(STATE_NONE),
 226       state_after_data_connect_complete_(STATE_CTRL_WRITE_SIZE) {}
 227
 228 FtpNetworkTransaction::~FtpNetworkTransaction() {
 229 }
 230
 231 int FtpNetworkTransaction::Stop(int error) {
 232   if (command_sent_ == COMMAND_QUIT)
 233     return error;
 234
 235   next_state_ = STATE_CTRL_WRITE_QUIT;
 236   last_error_ = error;
 237   return OK;
 238 }
 239
 240 int FtpNetworkTransaction::RestartIgnoringLastError(
 241     const CompletionCallback& callback) {
 242   return ERR_NOT_IMPLEMENTED;
 243 }
 244
 245 int FtpNetworkTransaction::Start(const FtpRequestInfo* request_info,
 246                                  const CompletionCallback& callback,
 247                                  const BoundNetLog& net_log) {
 248   net_log_ = net_log;
 249   request_ = request_info;
 250
 251   ctrl_response_buffer_.reset(new FtpCtrlResponseBuffer(net_log_));
 252
 253   if (request_->url.has_username()) {
 254     base::string16 username;
 255     base::string16 password;
 256     GetIdentityFromURL(request_->url, &username, &password);
 257     credentials_.Set(username, password);
 258   } else {
 259     credentials_.Set(base::ASCIIToUTF16("anonymous"),
 260                      base::ASCIIToUTF16("chrome@example.com"));
 261   }
 262
 263   DetectTypecode();
 264
 265   next_state_ = STATE_CTRL_RESOLVE_HOST;
 266   int rv = DoLoop(OK);
 267   if (rv == ERR_IO_PENDING)
 268     user_callback_ = callback;
 269   return rv;
 270 }
 271
 272 int FtpNetworkTransaction::RestartWithAuth(const AuthCredentials& credentials,
 273                                            const CompletionCallback& callback) {
 274   ResetStateForRestart();
 275
 276   credentials_ = credentials;
 277
 278   next_state_ = STATE_CTRL_RESOLVE_HOST;
 279   int rv = DoLoop(OK);
 280   if (rv == ERR_IO_PENDING)
 281     user_callback_ = callback;
 282   return rv;
 283 }
 284
 285 int FtpNetworkTransaction::Read(IOBuffer* buf,
 286                                 int buf_len,
 287                                 const CompletionCallback& callback) {
 288   DCHECK(buf);
 289   DCHECK_GT(buf_len, 0);
 290
 291   read_data_buf_ = buf;
 292   read_data_buf_len_ = buf_len;
 293
 294   next_state_ = STATE_DATA_READ;
 295   int rv = DoLoop(OK);
 296   if (rv == ERR_IO_PENDING)
 297     user_callback_ = callback;
 298   return rv;
 299 }
 300
 301 const FtpResponseInfo* FtpNetworkTransaction::GetResponseInfo() const {
 302   return &response_;
 303 }
 304
 305 LoadState FtpNetworkTransaction::GetLoadState() const {
 306   if (next_state_ == STATE_CTRL_RESOLVE_HOST_COMPLETE)
 307     return LOAD_STATE_RESOLVING_HOST;
 308
 309   if (next_state_ == STATE_CTRL_CONNECT_COMPLETE ||
 310       next_state_ == STATE_DATA_CONNECT_COMPLETE)
 311     return LOAD_STATE_CONNECTING;
 312
 313   if (next_state_ == STATE_DATA_READ_COMPLETE)
 314     return LOAD_STATE_READING_RESPONSE;
 315
 316   if (command_sent_ == COMMAND_RETR && read_data_buf_.get())
 317     return LOAD_STATE_READING_RESPONSE;
 318
 319   if (command_sent_ == COMMAND_QUIT)
 320     return LOAD_STATE_IDLE;
 321
 322   if (command_sent_ != COMMAND_NONE)
 323     return LOAD_STATE_SENDING_REQUEST;
 324
 325   return LOAD_STATE_IDLE;
 326 }
 327
 328 uint64 FtpNetworkTransaction::GetUploadProgress() const {
 329   return 0;
 330 }
 331
 332 void FtpNetworkTransaction::ResetStateForRestart() {
 333   command_sent_ = COMMAND_NONE;
 334   user_callback_.Reset();
 335   response_ = FtpResponseInfo();
 336   read_ctrl_buf_ = new IOBuffer(kCtrlBufLen);
 337   ctrl_response_buffer_.reset(new FtpCtrlResponseBuffer(net_log_));
 338   read_data_buf_ = NULL;
 339   read_data_buf_len_ = 0;
 340   if (write_buf_.get())
 341     write_buf_->SetOffset(0);
 342   last_error_ = OK;
 343   data_connection_port_ = 0;
 344   ctrl_socket_.reset();
 345   data_socket_.reset();
 346   next_state_ = STATE_NONE;
 347   state_after_data_connect_complete_ = STATE_CTRL_WRITE_SIZE;
 348 }
 349
 350 void FtpNetworkTransaction::ResetDataConnectionAfterError(State next_state) {
 351   // The server _might_ have reset the data connection
 352   // (see RFC 959 3.2. ESTABLISHING DATA CONNECTIONS:
 353   // "The server MUST close the data connection under the following
 354   // conditions:
 355   // ...
 356   // 5. An irrecoverable error condition occurs.")
 357   //
 358   // It is ambiguous what an irrecoverable error condition is,
 359   // so we take no chances.
 360   state_after_data_connect_complete_ = next_state;
 361   next_state_ = use_epsv_ ? STATE_CTRL_WRITE_EPSV : STATE_CTRL_WRITE_PASV;
 362 }
 363
 364 void FtpNetworkTransaction::DoCallback(int rv) {
 365   DCHECK(rv != ERR_IO_PENDING);
 366   DCHECK(!user_callback_.is_null());
 367
 368   // Since Run may result in Read being called, clear callback_ up front.
 369   CompletionCallback c = user_callback_;
 370   user_callback_.Reset();
 371   c.Run(rv);
 372 }
 373
 374 void FtpNetworkTransaction::OnIOComplete(int result) {
 375   int rv = DoLoop(result);
 376   if (rv != ERR_IO_PENDING)
 377     DoCallback(rv);
 378 }
 379
 380 int FtpNetworkTransaction::ProcessCtrlResponse() {
 381   FtpCtrlResponse response = ctrl_response_buffer_->PopResponse();
 382
 383   int rv = OK;
 384   switch (command_sent_) {
 385     case COMMAND_NONE:
 386       // TODO(phajdan.jr): Check for errors in the welcome message.
 387       next_state_ = STATE_CTRL_WRITE_USER;
 388       break;
 389     case COMMAND_USER:
 390       rv = ProcessResponseUSER(response);
 391       break;
 392     case COMMAND_PASS:
 393       rv = ProcessResponsePASS(response);
 394       break;
 395     case COMMAND_SYST:
 396       rv = ProcessResponseSYST(response);
 397       break;
 398     case COMMAND_PWD:
 399       rv = ProcessResponsePWD(response);
 400       break;
 401     case COMMAND_TYPE:
 402       rv = ProcessResponseTYPE(response);
 403       break;
 404     case COMMAND_EPSV:
 405       rv = ProcessResponseEPSV(response);
 406       break;
 407     case COMMAND_PASV:
 408       rv = ProcessResponsePASV(response);
 409       break;
 410     case COMMAND_SIZE:
 411       rv = ProcessResponseSIZE(response);
 412       break;
 413     case COMMAND_RETR:
 414       rv = ProcessResponseRETR(response);
 415       break;
 416     case COMMAND_CWD:
 417       rv = ProcessResponseCWD(response);
 418       break;
 419     case COMMAND_LIST:
 420       rv = ProcessResponseLIST(response);
 421       break;
 422     case COMMAND_QUIT:
 423       rv = ProcessResponseQUIT(response);
 424       break;
 425     default:
 426       LOG(DFATAL) << "Unexpected value of command_sent_: " << command_sent_;
 427       return ERR_UNEXPECTED;
 428   }
 429
 430   // We may get multiple responses for some commands,
 431   // see http://crbug.com/18036.
 432   while (ctrl_response_buffer_->ResponseAvailable() && rv == OK) {
 433     response = ctrl_response_buffer_->PopResponse();
 434
 435     switch (command_sent_) {
 436       case COMMAND_RETR:
 437         rv = ProcessResponseRETR(response);
 438         break;
 439       case COMMAND_LIST:
 440         rv = ProcessResponseLIST(response);
 441         break;
 442       default:
 443         // Multiple responses for other commands are invalid.
 444         return Stop(ERR_INVALID_RESPONSE);
 445     }
 446   }
 447
 448   return rv;
 449 }
 450
 451 // Used to prepare and send FTP command.
 452 int FtpNetworkTransaction::SendFtpCommand(const std::string& command,
 453                                           const std::string& command_for_log,
 454                                           Command cmd) {
 455   // If we send a new command when we still have unprocessed responses
 456   // for previous commands, the response receiving code will have no way to know
 457   // which responses are for which command.
 458   DCHECK(!ctrl_response_buffer_->ResponseAvailable());
 459
 460   DCHECK(!write_command_buf_.get());
 461   DCHECK(!write_buf_.get());
 462
 463   if (!IsValidFTPCommandString(command)) {
 464     // Callers should validate the command themselves and return a more specific
 465     // error code.
 466     NOTREACHED();
 467     return Stop(ERR_UNEXPECTED);
 468   }
 469
 470   command_sent_ = cmd;
 471
 472   write_command_buf_ = new IOBufferWithSize(command.length() + 2);
 473   write_buf_ = new DrainableIOBuffer(write_command_buf_.get(),
 474                                      write_command_buf_->size());
 475   memcpy(write_command_buf_->data(), command.data(), command.length());
 476   memcpy(write_command_buf_->data() + command.length(), kCRLF, 2);
 477
 478   net_log_.AddEvent(NetLog::TYPE_FTP_COMMAND_SENT,
 479                     NetLog::StringCallback("command", &command_for_log));
 480
 481   next_state_ = STATE_CTRL_WRITE;
 482   return OK;
 483 }
 484
 485 std::string FtpNetworkTransaction::GetRequestPathForFtpCommand(
 486     bool is_directory) const {
 487   std::string path(current_remote_directory_);
 488   if (request_->url.has_path()) {
 489     std::string gurl_path(request_->url.path());
 490
 491     // Get rid of the typecode, see RFC 1738 section 3.2.2. FTP url-path.
 492     std::string::size_type pos = gurl_path.rfind(';');
 493     if (pos != std::string::npos)
 494       gurl_path.resize(pos);
 495
 496     path.append(gurl_path);
 497   }
 498   // Make sure that if the path is expected to be a file, it won't end
 499   // with a trailing slash.
 500   if (!is_directory && path.length() > 1 && path[path.length() - 1] == '/')
 501     path.erase(path.length() - 1);
 502   UnescapeRule::Type unescape_rules = UnescapeRule::SPACES |
 503                                       UnescapeRule::URL_SPECIAL_CHARS;
 504   // This may unescape to non-ASCII characters, but we allow that. See the
 505   // comment for IsValidFTPCommandString.
 506   path = net::UnescapeURLComponent(path, unescape_rules);
 507
 508   if (system_type_ == SYSTEM_TYPE_VMS) {
 509     if (is_directory)
 510       path = FtpUtil::UnixDirectoryPathToVMS(path);
 511     else
 512       path = FtpUtil::UnixFilePathToVMS(path);
 513   }
 514
 515   DCHECK(IsValidFTPCommandString(path));
 516   return path;
 517 }
 518
 519 void FtpNetworkTransaction::DetectTypecode() {
 520   if (!request_->url.has_path())
 521     return;
 522   std::string gurl_path(request_->url.path());
 523
 524   // Extract the typecode, see RFC 1738 section 3.2.2. FTP url-path.
 525   std::string::size_type pos = gurl_path.rfind(';');
 526   if (pos == std::string::npos)
 527     return;
 528   std::string typecode_string(gurl_path.substr(pos));
 529   if (typecode_string == ";type=a") {
 530     data_type_ = DATA_TYPE_ASCII;
 531     resource_type_ = RESOURCE_TYPE_FILE;
 532   } else if (typecode_string == ";type=i") {
 533     data_type_ = DATA_TYPE_IMAGE;
 534     resource_type_ = RESOURCE_TYPE_FILE;
 535   } else if (typecode_string == ";type=d") {
 536     resource_type_ = RESOURCE_TYPE_DIRECTORY;
 537   }
 538 }
 539
 540 int FtpNetworkTransaction::DoLoop(int result) {
 541   DCHECK(next_state_ != STATE_NONE);
 542
 543   int rv = result;
 544   do {
 545     State state = next_state_;
 546     next_state_ = STATE_NONE;
 547     switch (state) {
 548       case STATE_CTRL_RESOLVE_HOST:
 549         DCHECK(rv == OK);
 550         rv = DoCtrlResolveHost();
 551         break;
 552       case STATE_CTRL_RESOLVE_HOST_COMPLETE:
 553         rv = DoCtrlResolveHostComplete(rv);
 554         break;
 555       case STATE_CTRL_CONNECT:
 556         DCHECK(rv == OK);
 557         rv = DoCtrlConnect();
 558         break;
 559       case STATE_CTRL_CONNECT_COMPLETE:
 560         rv = DoCtrlConnectComplete(rv);
 561         break;
 562       case STATE_CTRL_READ:
 563         DCHECK(rv == OK);
 564         rv = DoCtrlRead();
 565         break;
 566       case STATE_CTRL_READ_COMPLETE:
 567         rv = DoCtrlReadComplete(rv);
 568         break;
 569       case STATE_CTRL_WRITE:
 570         DCHECK(rv == OK);
 571         rv = DoCtrlWrite();
 572         break;
 573       case STATE_CTRL_WRITE_COMPLETE:
 574         rv = DoCtrlWriteComplete(rv);
 575         break;
 576       case STATE_CTRL_WRITE_USER:
 577         DCHECK(rv == OK);
 578         rv = DoCtrlWriteUSER();
 579         break;
 580       case STATE_CTRL_WRITE_PASS:
 581         DCHECK(rv == OK);
 582         rv = DoCtrlWritePASS();
 583         break;
 584       case STATE_CTRL_WRITE_SYST:
 585         DCHECK(rv == OK);
 586         rv = DoCtrlWriteSYST();
 587         break;
 588       case STATE_CTRL_WRITE_PWD:
 589         DCHECK(rv == OK);
 590         rv = DoCtrlWritePWD();
 591         break;
 592       case STATE_CTRL_WRITE_TYPE:
 593         DCHECK(rv == OK);
 594         rv = DoCtrlWriteTYPE();
 595         break;
 596       case STATE_CTRL_WRITE_EPSV:
 597         DCHECK(rv == OK);
 598         rv = DoCtrlWriteEPSV();
 599         break;
 600       case STATE_CTRL_WRITE_PASV:
 601         DCHECK(rv == OK);
 602         rv = DoCtrlWritePASV();
 603         break;
 604       case STATE_CTRL_WRITE_RETR:
 605         DCHECK(rv == OK);
 606         rv = DoCtrlWriteRETR();
 607         break;
 608       case STATE_CTRL_WRITE_SIZE:
 609         DCHECK(rv == OK);
 610         rv = DoCtrlWriteSIZE();
 611         break;
 612       case STATE_CTRL_WRITE_CWD:
 613         DCHECK(rv == OK);
 614         rv = DoCtrlWriteCWD();
 615         break;
 616       case STATE_CTRL_WRITE_LIST:
 617         DCHECK(rv == OK);
 618         rv = DoCtrlWriteLIST();
 619         break;
 620       case STATE_CTRL_WRITE_QUIT:
 621         DCHECK(rv == OK);
 622         rv = DoCtrlWriteQUIT();
 623         break;
 624       case STATE_DATA_CONNECT:
 625         DCHECK(rv == OK);
 626         rv = DoDataConnect();
 627         break;
 628       case STATE_DATA_CONNECT_COMPLETE:
 629         rv = DoDataConnectComplete(rv);
 630         break;
 631       case STATE_DATA_READ:
 632         DCHECK(rv == OK);
 633         rv = DoDataRead();
 634         break;
 635       case STATE_DATA_READ_COMPLETE:
 636         rv = DoDataReadComplete(rv);
 637         break;
 638       default:
 639         NOTREACHED() << "bad state";
 640         rv = ERR_UNEXPECTED;
 641         break;
 642     }
 643   } while (rv != ERR_IO_PENDING && next_state_ != STATE_NONE);
 644   return rv;
 645 }
 646
 647 int FtpNetworkTransaction::DoCtrlResolveHost() {
 648   next_state_ = STATE_CTRL_RESOLVE_HOST_COMPLETE;
 649
 650   HostResolver::RequestInfo info(HostPortPair::FromURL(request_->url));
 651   // No known referrer.
 652   return resolver_.Resolve(
 653       info,
 654       DEFAULT_PRIORITY,
 655       &addresses_,
 656       base::Bind(&FtpNetworkTransaction::OnIOComplete, base::Unretained(this)),
 657       net_log_);
 658 }
 659
 660 int FtpNetworkTransaction::DoCtrlResolveHostComplete(int result) {
 661   if (result == OK)
 662     next_state_ = STATE_CTRL_CONNECT;
 663   return result;
 664 }
 665
 666 int FtpNetworkTransaction::DoCtrlConnect() {
 667   next_state_ = STATE_CTRL_CONNECT_COMPLETE;
 668   ctrl_socket_ = socket_factory_->CreateTransportClientSocket(
 669       addresses_, net_log_.net_log(), net_log_.source());
 670   net_log_.AddEvent(
 671       NetLog::TYPE_FTP_CONTROL_CONNECTION,
 672       ctrl_socket_->NetLog().source().ToEventParametersCallback());
 673   return ctrl_socket_->Connect(io_callback_);
 674 }
 675
 676 int FtpNetworkTransaction::DoCtrlConnectComplete(int result) {
 677   if (result == OK) {
 678     // Put the peer's IP address and port into the response.
 679     IPEndPoint ip_endpoint;
 680     result = ctrl_socket_->GetPeerAddress(&ip_endpoint);
 681     if (result == OK) {
 682       response_.socket_address = HostPortPair::FromIPEndPoint(ip_endpoint);
 683       next_state_ = STATE_CTRL_READ;
 684
 685       if (ip_endpoint.GetFamily() == ADDRESS_FAMILY_IPV4) {
 686         // Do not use EPSV for IPv4 connections. Some servers become confused
 687         // and we time out while waiting to connect. PASV is perfectly fine for
 688         // IPv4. Note that this blacklists IPv4 not to use EPSV instead of
 689         // whitelisting IPv6 to use it, to make the code more future-proof:
 690         // all future protocols should just use EPSV.
 691         use_epsv_ = false;
 692       }
 693     }
 694   }
 695   return result;
 696 }
 697
 698 int FtpNetworkTransaction::DoCtrlRead() {
 699   next_state_ = STATE_CTRL_READ_COMPLETE;
 700   return ctrl_socket_->Read(read_ctrl_buf_.get(), kCtrlBufLen, io_callback_);
 701 }
 702
 703 int FtpNetworkTransaction::DoCtrlReadComplete(int result) {
 704   if (result == 0) {
 705     // Some servers (for example Pure-FTPd) apparently close the control
 706     // connection when anonymous login is not permitted. For more details
 707     // see http://crbug.com/25023.
 708     if (command_sent_ == COMMAND_USER &&
 709         credentials_.username() == base::ASCIIToUTF16("anonymous")) {
 710       response_.needs_auth = true;
 711     }
 712     return Stop(ERR_EMPTY_RESPONSE);
 713   }
 714   if (result < 0)
 715     return Stop(result);
 716
 717   ctrl_response_buffer_->ConsumeData(read_ctrl_buf_->data(), result);
 718
 719   if (!ctrl_response_buffer_->ResponseAvailable()) {
 720     // Read more data from the control socket.
 721     next_state_ = STATE_CTRL_READ;
 722     return OK;
 723   }
 724
 725   return ProcessCtrlResponse();
 726 }
 727
 728 int FtpNetworkTransaction::DoCtrlWrite() {
 729   next_state_ = STATE_CTRL_WRITE_COMPLETE;
 730
 731   return ctrl_socket_->Write(
 732       write_buf_.get(), write_buf_->BytesRemaining(), io_callback_);
 733 }
 734
 735 int FtpNetworkTransaction::DoCtrlWriteComplete(int result) {
 736   if (result < 0)
 737     return result;
 738
 739   write_buf_->DidConsume(result);
 740   if (write_buf_->BytesRemaining() == 0) {
 741     // Clear the write buffer.
 742     write_buf_ = NULL;
 743     write_command_buf_ = NULL;
 744
 745     next_state_ = STATE_CTRL_READ;
 746   } else {
 747     next_state_ = STATE_CTRL_WRITE;
 748   }
 749   return OK;
 750 }
 751
 752 // FTP Commands and responses
 753
 754 // USER Command.
 755 int FtpNetworkTransaction::DoCtrlWriteUSER() {
 756   std::string command = "USER " + base::UTF16ToUTF8(credentials_.username());
 757
 758   if (!IsValidFTPCommandString(command))
 759     return Stop(ERR_MALFORMED_IDENTITY);
 760
 761   next_state_ = STATE_CTRL_READ;
 762   return SendFtpCommand(command, "USER ***", COMMAND_USER);
 763 }
 764
 765 int FtpNetworkTransaction::ProcessResponseUSER(
 766     const FtpCtrlResponse& response) {
 767   switch (GetErrorClass(response.status_code)) {
 768     case ERROR_CLASS_OK:
 769       next_state_ = STATE_CTRL_WRITE_SYST;
 770       break;
 771     case ERROR_CLASS_INFO_NEEDED:
 772       next_state_ = STATE_CTRL_WRITE_PASS;
 773       break;
 774     case ERROR_CLASS_TRANSIENT_ERROR:
 775     case ERROR_CLASS_PERMANENT_ERROR:
 776       response_.needs_auth = true;
 777       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 778     default:
 779       NOTREACHED();
 780       return Stop(ERR_UNEXPECTED);
 781   }
 782   return OK;
 783 }
 784
 785 // PASS command.
 786 int FtpNetworkTransaction::DoCtrlWritePASS() {
 787   std::string command = "PASS " + base::UTF16ToUTF8(credentials_.password());
 788
 789   if (!IsValidFTPCommandString(command))
 790     return Stop(ERR_MALFORMED_IDENTITY);
 791
 792   next_state_ = STATE_CTRL_READ;
 793   return SendFtpCommand(command, "PASS ***", COMMAND_PASS);
 794 }
 795
 796 int FtpNetworkTransaction::ProcessResponsePASS(
 797     const FtpCtrlResponse& response) {
 798   switch (GetErrorClass(response.status_code)) {
 799     case ERROR_CLASS_OK:
 800       next_state_ = STATE_CTRL_WRITE_SYST;
 801       break;
 802     case ERROR_CLASS_INFO_NEEDED:
 803       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 804     case ERROR_CLASS_TRANSIENT_ERROR:
 805     case ERROR_CLASS_PERMANENT_ERROR:
 806       response_.needs_auth = true;
 807       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 808     default:
 809       NOTREACHED();
 810       return Stop(ERR_UNEXPECTED);
 811   }
 812   return OK;
 813 }
 814
 815 // SYST command.
 816 int FtpNetworkTransaction::DoCtrlWriteSYST() {
 817   std::string command = "SYST";
 818   next_state_ = STATE_CTRL_READ;
 819   return SendFtpCommand(command, command, COMMAND_SYST);
 820 }
 821
 822 int FtpNetworkTransaction::ProcessResponseSYST(
 823     const FtpCtrlResponse& response) {
 824   switch (GetErrorClass(response.status_code)) {
 825     case ERROR_CLASS_INITIATED:
 826       return Stop(ERR_INVALID_RESPONSE);
 827     case ERROR_CLASS_OK: {
 828       // All important info should be on the first line.
 829       std::string line = response.lines[0];
 830       // The response should be ASCII, which allows us to do case-insensitive
 831       // comparisons easily. If it is not ASCII, we leave the system type
 832       // as unknown.
 833       if (base::IsStringASCII(line)) {
 834         line = base::StringToLowerASCII(line);
 835
 836         // Remove all whitespace, to correctly handle cases like fancy "V M S"
 837         // response instead of "VMS".
 838         base::RemoveChars(line, base::kWhitespaceASCII, &line);
 839
 840         // The "magic" strings we test for below have been gathered by an
 841         // empirical study. VMS needs to come first because some VMS systems
 842         // also respond with "UNIX emulation", which is not perfect. It is much
 843         // more reliable to talk to these servers in their native language.
 844         if (line.find("vms") != std::string::npos) {
 845           system_type_ = SYSTEM_TYPE_VMS;
 846         } else if (line.find("l8") != std::string::npos ||
 847                    line.find("unix") != std::string::npos ||
 848                    line.find("bsd") != std::string::npos) {
 849           system_type_ = SYSTEM_TYPE_UNIX;
 850         } else if (line.find("win32") != std::string::npos ||
 851                    line.find("windows") != std::string::npos) {
 852           system_type_ = SYSTEM_TYPE_WINDOWS;
 853         } else if (line.find("os/2") != std::string::npos) {
 854           system_type_ = SYSTEM_TYPE_OS2;
 855         }
 856       }
 857       next_state_ = STATE_CTRL_WRITE_PWD;
 858       break;
 859     }
 860     case ERROR_CLASS_INFO_NEEDED:
 861       return Stop(ERR_INVALID_RESPONSE);
 862     case ERROR_CLASS_TRANSIENT_ERROR:
 863       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 864     case ERROR_CLASS_PERMANENT_ERROR:
 865       // Server does not recognize the SYST command so proceed.
 866       next_state_ = STATE_CTRL_WRITE_PWD;
 867       break;
 868     default:
 869       NOTREACHED();
 870       return Stop(ERR_UNEXPECTED);
 871   }
 872   return OK;
 873 }
 874
 875 // PWD command.
 876 int FtpNetworkTransaction::DoCtrlWritePWD() {
 877   std::string command = "PWD";
 878   next_state_ = STATE_CTRL_READ;
 879   return SendFtpCommand(command, command, COMMAND_PWD);
 880 }
 881
 882 int FtpNetworkTransaction::ProcessResponsePWD(const FtpCtrlResponse& response) {
 883   switch (GetErrorClass(response.status_code)) {
 884     case ERROR_CLASS_INITIATED:
 885       return Stop(ERR_INVALID_RESPONSE);
 886     case ERROR_CLASS_OK: {
 887       // The info we look for should be on the first line.
 888       std::string line = response.lines[0];
 889       if (line.empty())
 890         return Stop(ERR_INVALID_RESPONSE);
 891       std::string::size_type quote_pos = line.find('"');
 892       if (quote_pos != std::string::npos) {
 893         line = line.substr(quote_pos + 1);
 894         quote_pos = line.find('"');
 895         if (quote_pos == std::string::npos)
 896           return Stop(ERR_INVALID_RESPONSE);
 897         line = line.substr(0, quote_pos);
 898       }
 899       if (system_type_ == SYSTEM_TYPE_VMS)
 900         line = FtpUtil::VMSPathToUnix(line);
 901       if (line.length() && line[line.length() - 1] == '/')
 902         line.erase(line.length() - 1);
 903       current_remote_directory_ = line;
 904       next_state_ = STATE_CTRL_WRITE_TYPE;
 905       break;
 906     }
 907     case ERROR_CLASS_INFO_NEEDED:
 908       return Stop(ERR_INVALID_RESPONSE);
 909     case ERROR_CLASS_TRANSIENT_ERROR:
 910       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 911     case ERROR_CLASS_PERMANENT_ERROR:
 912       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 913     default:
 914       NOTREACHED();
 915       return Stop(ERR_UNEXPECTED);
 916   }
 917   return OK;
 918 }
 919
 920 // TYPE command.
 921 int FtpNetworkTransaction::DoCtrlWriteTYPE() {
 922   std::string command = "TYPE ";
 923   if (data_type_ == DATA_TYPE_ASCII) {
 924     command += "A";
 925   } else if (data_type_ == DATA_TYPE_IMAGE) {
 926     command += "I";
 927   } else {
 928     NOTREACHED();
 929     return Stop(ERR_UNEXPECTED);
 930   }
 931   next_state_ = STATE_CTRL_READ;
 932   return SendFtpCommand(command, command, COMMAND_TYPE);
 933 }
 934
 935 int FtpNetworkTransaction::ProcessResponseTYPE(
 936     const FtpCtrlResponse& response) {
 937   switch (GetErrorClass(response.status_code)) {
 938     case ERROR_CLASS_INITIATED:
 939       return Stop(ERR_INVALID_RESPONSE);
 940     case ERROR_CLASS_OK:
 941       next_state_ = use_epsv_ ? STATE_CTRL_WRITE_EPSV : STATE_CTRL_WRITE_PASV;
 942       break;
 943     case ERROR_CLASS_INFO_NEEDED:
 944       return Stop(ERR_INVALID_RESPONSE);
 945     case ERROR_CLASS_TRANSIENT_ERROR:
 946       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 947     case ERROR_CLASS_PERMANENT_ERROR:
 948       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 949     default:
 950       NOTREACHED();
 951       return Stop(ERR_UNEXPECTED);
 952   }
 953   return OK;
 954 }
 955
 956 // EPSV command
 957 int FtpNetworkTransaction::DoCtrlWriteEPSV() {
 958   const std::string command = "EPSV";
 959   next_state_ = STATE_CTRL_READ;
 960   return SendFtpCommand(command, command, COMMAND_EPSV);
 961 }
 962
 963 int FtpNetworkTransaction::ProcessResponseEPSV(
 964     const FtpCtrlResponse& response) {
 965   switch (GetErrorClass(response.status_code)) {
 966     case ERROR_CLASS_INITIATED:
 967       return Stop(ERR_INVALID_RESPONSE);
 968     case ERROR_CLASS_OK:
 969       if (!ExtractPortFromEPSVResponse( response, &data_connection_port_))
 970         return Stop(ERR_INVALID_RESPONSE);
 971       if (data_connection_port_ < 1024 ||
 972           !IsPortAllowedByFtp(data_connection_port_))
 973         return Stop(ERR_UNSAFE_PORT);
 974       next_state_ = STATE_DATA_CONNECT;
 975       break;
 976     case ERROR_CLASS_INFO_NEEDED:
 977       return Stop(ERR_INVALID_RESPONSE);
 978     case ERROR_CLASS_TRANSIENT_ERROR:
 979     case ERROR_CLASS_PERMANENT_ERROR:
 980       use_epsv_ = false;
 981       next_state_ = STATE_CTRL_WRITE_PASV;
 982       return OK;
 983     default:
 984       NOTREACHED();
 985       return Stop(ERR_UNEXPECTED);
 986   }
 987   return OK;
 988 }
 989
 990 // PASV command
 991 int FtpNetworkTransaction::DoCtrlWritePASV() {
 992   std::string command = "PASV";
 993   next_state_ = STATE_CTRL_READ;
 994   return SendFtpCommand(command, command, COMMAND_PASV);
 995 }
 996
 997 int FtpNetworkTransaction::ProcessResponsePASV(
 998     const FtpCtrlResponse& response) {
 999   switch (GetErrorClass(response.status_code)) {
1000     case ERROR_CLASS_INITIATED:
1001       return Stop(ERR_INVALID_RESPONSE);
1002     case ERROR_CLASS_OK:
1003       if (!ExtractPortFromPASVResponse(response, &data_connection_port_))
1004         return Stop(ERR_INVALID_RESPONSE);
1005       if (data_connection_port_ < 1024 ||
1006           !IsPortAllowedByFtp(data_connection_port_))
1007         return Stop(ERR_UNSAFE_PORT);
1008       next_state_ = STATE_DATA_CONNECT;
1009       break;
1010     case ERROR_CLASS_INFO_NEEDED:
1011       return Stop(ERR_INVALID_RESPONSE);
1012     case ERROR_CLASS_TRANSIENT_ERROR:
1013       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1014     case ERROR_CLASS_PERMANENT_ERROR:
1015       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1016     default:
1017       NOTREACHED();
1018       return Stop(ERR_UNEXPECTED);
1019   }
1020   return OK;
1021 }
1022
1023 // RETR command
1024 int FtpNetworkTransaction::DoCtrlWriteRETR() {
1025   std::string command = "RETR " + GetRequestPathForFtpCommand(false);
1026   next_state_ = STATE_CTRL_READ;
1027   return SendFtpCommand(command, command, COMMAND_RETR);
1028 }
1029
1030 int FtpNetworkTransaction::ProcessResponseRETR(
1031     const FtpCtrlResponse& response) {
1032   switch (GetErrorClass(response.status_code)) {
1033     case ERROR_CLASS_INITIATED:
1034       // We want the client to start reading the response at this point.
1035       // It got here either through Start or RestartWithAuth. We want that
1036       // method to complete. Not setting next state here will make DoLoop exit
1037       // and in turn make Start/RestartWithAuth complete.
1038       resource_type_ = RESOURCE_TYPE_FILE;
1039       break;
1040     case ERROR_CLASS_OK:
1041       resource_type_ = RESOURCE_TYPE_FILE;
1042       next_state_ = STATE_CTRL_WRITE_QUIT;
1043       break;
1044     case ERROR_CLASS_INFO_NEEDED:
1045       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1046     case ERROR_CLASS_TRANSIENT_ERROR:
1047       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1048     case ERROR_CLASS_PERMANENT_ERROR:
1049       // Code 550 means "Failed to open file". Other codes are unrelated,
1050       // like "Not logged in" etc.
1051       if (response.status_code != 550 || resource_type_ == RESOURCE_TYPE_FILE)
1052         return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1053
1054       // It's possible that RETR failed because the path is a directory.
1055       resource_type_ = RESOURCE_TYPE_DIRECTORY;
1056
1057       // We're going to try CWD next, but first send a PASV one more time,
1058       // because some FTP servers, including FileZilla, require that.
1059       // See http://crbug.com/25316.
1060       next_state_ = use_epsv_ ? STATE_CTRL_WRITE_EPSV : STATE_CTRL_WRITE_PASV;
1061       break;
1062     default:
1063       NOTREACHED();
1064       return Stop(ERR_UNEXPECTED);
1065   }
1066
1067   // We should be sure about our resource type now. Otherwise we risk
1068   // an infinite loop (RETR can later send CWD, and CWD can later send RETR).
1069   DCHECK_NE(RESOURCE_TYPE_UNKNOWN, resource_type_);
1070
1071   return OK;
1072 }
1073
1074 // SIZE command
1075 int FtpNetworkTransaction::DoCtrlWriteSIZE() {
1076   std::string command = "SIZE " + GetRequestPathForFtpCommand(false);
1077   next_state_ = STATE_CTRL_READ;
1078   return SendFtpCommand(command, command, COMMAND_SIZE);
1079 }
1080
1081 int FtpNetworkTransaction::ProcessResponseSIZE(
1082     const FtpCtrlResponse& response) {
1083   State state_after_size;
1084   if (resource_type_ == RESOURCE_TYPE_FILE)
1085     state_after_size = STATE_CTRL_WRITE_RETR;
1086   else
1087     state_after_size = STATE_CTRL_WRITE_CWD;
1088
1089   switch (GetErrorClass(response.status_code)) {
1090     case ERROR_CLASS_INITIATED:
1091       next_state_ = state_after_size;
1092       break;
1093     case ERROR_CLASS_OK:
1094       if (response.lines.size() != 1)
1095         return Stop(ERR_INVALID_RESPONSE);
1096       int64 size;
1097       if (!base::StringToInt64(response.lines[0], &size))
1098         return Stop(ERR_INVALID_RESPONSE);
1099       if (size < 0)
1100         return Stop(ERR_INVALID_RESPONSE);
1101
1102       // A successful response to SIZE does not mean the resource is a file.
1103       // Some FTP servers (for example, the qnx one) send a SIZE even for
1104       // directories.
1105       response_.expected_content_size = size;
1106
1107       next_state_ = state_after_size;
1108       break;
1109     case ERROR_CLASS_INFO_NEEDED:
1110       next_state_ = state_after_size;
1111       break;
1112     case ERROR_CLASS_TRANSIENT_ERROR:
1113       ResetDataConnectionAfterError(state_after_size);
1114       break;
1115     case ERROR_CLASS_PERMANENT_ERROR:
1116       // It's possible that SIZE failed because the path is a directory.
1117       if (resource_type_ == RESOURCE_TYPE_UNKNOWN &&
1118           response.status_code != 550) {
1119         return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1120       }
1121
1122       ResetDataConnectionAfterError(state_after_size);
1123       break;
1124     default:
1125       NOTREACHED();
1126       return Stop(ERR_UNEXPECTED);
1127   }
1128
1129   return OK;
1130 }
1131
1132 // CWD command
1133 int FtpNetworkTransaction::DoCtrlWriteCWD() {
1134   std::string command = "CWD " + GetRequestPathForFtpCommand(true);
1135   next_state_ = STATE_CTRL_READ;
1136   return SendFtpCommand(command, command, COMMAND_CWD);
1137 }
1138
1139 int FtpNetworkTransaction::ProcessResponseCWD(const FtpCtrlResponse& response) {
1140   // We should never issue CWD if we know the target resource is a file.
1141   DCHECK_NE(RESOURCE_TYPE_FILE, resource_type_);
1142
1143   switch (GetErrorClass(response.status_code)) {
1144     case ERROR_CLASS_INITIATED:
1145       return Stop(ERR_INVALID_RESPONSE);
1146     case ERROR_CLASS_OK:
1147       next_state_ = STATE_CTRL_WRITE_LIST;
1148       break;
1149     case ERROR_CLASS_INFO_NEEDED:
1150       return Stop(ERR_INVALID_RESPONSE);
1151     case ERROR_CLASS_TRANSIENT_ERROR:
1152       // Some FTP servers send response 451 (not a valid CWD response according
1153       // to RFC 959) instead of 550.
1154       if (response.status_code == 451)
1155         return ProcessResponseCWDNotADirectory();
1156
1157       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1158     case ERROR_CLASS_PERMANENT_ERROR:
1159       if (response.status_code == 550)
1160         return ProcessResponseCWDNotADirectory();
1161
1162       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1163     default:
1164       NOTREACHED();
1165       return Stop(ERR_UNEXPECTED);
1166   }
1167
1168   return OK;
1169 }
1170
1171 int FtpNetworkTransaction::ProcessResponseCWDNotADirectory() {
1172   if (resource_type_ == RESOURCE_TYPE_DIRECTORY) {
1173     // We're assuming that the resource is a directory, but the server
1174     // says it's not true. The most probable interpretation is that it
1175     // doesn't exist (with FTP we can't be sure).
1176     return Stop(ERR_FILE_NOT_FOUND);
1177   }
1178
1179   // We are here because SIZE failed and we are not sure what the resource
1180   // type is. It could still be file, and SIZE could fail because of
1181   // an access error (http://crbug.com/56734). Try RETR just to be sure.
1182   resource_type_ = RESOURCE_TYPE_FILE;
1183
1184   ResetDataConnectionAfterError(STATE_CTRL_WRITE_RETR);
1185   return OK;
1186 }
1187
1188 // LIST command
1189 int FtpNetworkTransaction::DoCtrlWriteLIST() {
1190   // Use the -l option for mod_ftp configured in LISTIsNLST mode: the option
1191   // forces LIST output instead of NLST (which would be ambiguous for us
1192   // to parse).
1193   std::string command("LIST -l");
1194   if (system_type_ == SYSTEM_TYPE_VMS)
1195     command = "LIST *.*;0";
1196
1197   next_state_ = STATE_CTRL_READ;
1198   return SendFtpCommand(command, command, COMMAND_LIST);
1199 }
1200
1201 int FtpNetworkTransaction::ProcessResponseLIST(
1202     const FtpCtrlResponse& response) {
1203   switch (GetErrorClass(response.status_code)) {
1204     case ERROR_CLASS_INITIATED:
1205       // We want the client to start reading the response at this point.
1206       // It got here either through Start or RestartWithAuth. We want that
1207       // method to complete. Not setting next state here will make DoLoop exit
1208       // and in turn make Start/RestartWithAuth complete.
1209       response_.is_directory_listing = true;
1210       break;
1211     case ERROR_CLASS_OK:
1212       response_.is_directory_listing = true;
1213       next_state_ = STATE_CTRL_WRITE_QUIT;
1214       break;
1215     case ERROR_CLASS_INFO_NEEDED:
1216       return Stop(ERR_INVALID_RESPONSE);
1217     case ERROR_CLASS_TRANSIENT_ERROR:
1218       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1219     case ERROR_CLASS_PERMANENT_ERROR:
1220       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1221     default:
1222       NOTREACHED();
1223       return Stop(ERR_UNEXPECTED);
1224   }
1225   return OK;
1226 }
1227
1228 // QUIT command
1229 int FtpNetworkTransaction::DoCtrlWriteQUIT() {
1230   std::string command = "QUIT";
1231   next_state_ = STATE_CTRL_READ;
1232   return SendFtpCommand(command, command, COMMAND_QUIT);
1233 }
1234
1235 int FtpNetworkTransaction::ProcessResponseQUIT(
1236     const FtpCtrlResponse& response) {
1237   ctrl_socket_->Disconnect();
1238   return last_error_;
1239 }
1240
1241 // Data Connection
1242
1243 int FtpNetworkTransaction::DoDataConnect() {
1244   next_state_ = STATE_DATA_CONNECT_COMPLETE;
1245   IPEndPoint ip_endpoint;
1246   AddressList data_address;
1247   // Connect to the same host as the control socket to prevent PASV port
1248   // scanning attacks.
1249   int rv = ctrl_socket_->GetPeerAddress(&ip_endpoint);
1250   if (rv != OK)
1251     return Stop(rv);
1252   data_address = AddressList::CreateFromIPAddress(
1253       ip_endpoint.address(), data_connection_port_);
1254   data_socket_ = socket_factory_->CreateTransportClientSocket(
1255         data_address, net_log_.net_log(), net_log_.source());
1256   net_log_.AddEvent(
1257       NetLog::TYPE_FTP_DATA_CONNECTION,
1258       data_socket_->NetLog().source().ToEventParametersCallback());
1259   return data_socket_->Connect(io_callback_);
1260 }
1261
1262 int FtpNetworkTransaction::DoDataConnectComplete(int result) {
1263   if (result != OK && use_epsv_) {
1264     // It's possible we hit a broken server, sadly. They can break in different
1265     // ways. Some time out, some reset a connection. Fall back to PASV.
1266     // TODO(phajdan.jr): remember it for future transactions with this server.
1267     // TODO(phajdan.jr): write a test for this code path.
1268     use_epsv_ = false;
1269     next_state_ = STATE_CTRL_WRITE_PASV;
1270     return OK;
1271   }
1272
1273   // Only record the connection error after we've applied all our fallbacks.
1274   // We want to capture the final error, one we're not going to recover from.
1275   RecordDataConnectionError(result);
1276
1277   if (result != OK)
1278     return Stop(result);
1279
1280   next_state_ = state_after_data_connect_complete_;
1281   return OK;
1282 }
1283
1284 int FtpNetworkTransaction::DoDataRead() {
1285   DCHECK(read_data_buf_.get());
1286   DCHECK_GT(read_data_buf_len_, 0);
1287
1288   if (data_socket_ == NULL || !data_socket_->IsConnected()) {
1289     // If we don't destroy the data socket completely, some servers will wait
1290     // for us (http://crbug.com/21127). The half-closed TCP connection needs
1291     // to be closed on our side too.
1292     data_socket_.reset();
1293
1294     if (ctrl_socket_->IsConnected()) {
1295       // Wait for the server's response, we should get it before sending QUIT.
1296       next_state_ = STATE_CTRL_READ;
1297       return OK;
1298     }
1299
1300     // We are no longer connected to the server, so just finish the transaction.
1301     return Stop(OK);
1302   }
1303
1304   next_state_ = STATE_DATA_READ_COMPLETE;
1305   read_data_buf_->data()[0] = 0;
1306   return data_socket_->Read(
1307       read_data_buf_.get(), read_data_buf_len_, io_callback_);
1308 }
1309
1310 int FtpNetworkTransaction::DoDataReadComplete(int result) {
1311   return result;
1312 }
1313
1314 // We're using a histogram as a group of counters, with one bucket for each
1315 // enumeration value.  We're only interested in the values of the counters.
1316 // Ignore the shape, average, and standard deviation of the histograms because
1317 // they are meaningless.
1318 //
1319 // We use two histograms.  In the first histogram we tally whether the user has
1320 // seen an error of that type during the session.  In the second histogram we
1321 // tally the total number of times the users sees each errer.
1322 void FtpNetworkTransaction::RecordDataConnectionError(int result) {
1323   // Gather data for http://crbug.com/3073. See how many users have trouble
1324   // establishing FTP data connection in passive FTP mode.
1325   enum {
1326     // Data connection successful.
1327     NET_ERROR_OK = 0,
1328
1329     // Local firewall blocked the connection.
1330     NET_ERROR_ACCESS_DENIED = 1,
1331
1332     // Connection timed out.
1333     NET_ERROR_TIMED_OUT = 2,
1334
1335     // Connection has been estabilished, but then got broken (either reset
1336     // or aborted).
1337     NET_ERROR_CONNECTION_BROKEN = 3,
1338
1339     // Connection has been refused.
1340     NET_ERROR_CONNECTION_REFUSED = 4,
1341
1342     // No connection to the internet.
1343     NET_ERROR_INTERNET_DISCONNECTED = 5,
1344
1345     // Could not reach the destination address.
1346     NET_ERROR_ADDRESS_UNREACHABLE = 6,
1347
1348     // A programming error in our network stack.
1349     NET_ERROR_UNEXPECTED = 7,
1350
1351     // Other kind of error.
1352     NET_ERROR_OTHER = 20,
1353
1354     NUM_OF_NET_ERROR_TYPES
1355   } type;
1356   switch (result) {
1357     case OK:
1358       type = NET_ERROR_OK;
1359       break;
1360     case ERR_ACCESS_DENIED:
1361     case ERR_NETWORK_ACCESS_DENIED:
1362       type = NET_ERROR_ACCESS_DENIED;
1363       break;
1364     case ERR_TIMED_OUT:
1365       type = NET_ERROR_TIMED_OUT;
1366       break;
1367     case ERR_CONNECTION_ABORTED:
1368     case ERR_CONNECTION_RESET:
1369     case ERR_CONNECTION_CLOSED:
1370       type = NET_ERROR_CONNECTION_BROKEN;
1371       break;
1372     case ERR_CONNECTION_FAILED:
1373     case ERR_CONNECTION_REFUSED:
1374       type = NET_ERROR_CONNECTION_REFUSED;
1375       break;
1376     case ERR_INTERNET_DISCONNECTED:
1377       type = NET_ERROR_INTERNET_DISCONNECTED;
1378       break;
1379     case ERR_ADDRESS_INVALID:
1380     case ERR_ADDRESS_UNREACHABLE:
1381       type = NET_ERROR_ADDRESS_UNREACHABLE;
1382       break;
1383     case ERR_UNEXPECTED:
1384       type = NET_ERROR_UNEXPECTED;
1385       break;
1386     default:
1387       type = NET_ERROR_OTHER;
1388       break;
1389   };
1390   static bool had_error_type[NUM_OF_NET_ERROR_TYPES];
1391
1392   DCHECK(type >= 0 && type < NUM_OF_NET_ERROR_TYPES);
1393   if (!had_error_type[type]) {
1394     had_error_type[type] = true;
1395     UMA_HISTOGRAM_ENUMERATION("Net.FtpDataConnectionErrorHappened",
1396         type, NUM_OF_NET_ERROR_TYPES);
1397   }
1398   UMA_HISTOGRAM_ENUMERATION("Net.FtpDataConnectionErrorCount",
1399       type, NUM_OF_NET_ERROR_TYPES);
1400 }
1401
1402 }  // namespace net