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_macros.h"
  11 #include "base/strings/string_number_conversions.h"
  12 #include "base/strings/string_split.h"
  13 #include "base/strings/string_util.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_util.h"
  21 #include "net/base/port_util.h"
  22 #include "net/ftp/ftp_request_info.h"
  23 #include "net/ftp/ftp_util.h"
  24 #include "net/log/net_log.h"
  25 #include "net/socket/client_socket_factory.h"
  26 #include "net/socket/stream_socket.h"
  27 #include "url/url_constants.h"
  28
  29 namespace net {
  30
  31 namespace {
  32
  33 const char kCRLF[] = "\r\n";
  34
  35 const int kCtrlBufLen = 1024;
  36
  37 // Returns true if |input| can be safely used as a part of FTP command.
  38 bool IsValidFTPCommandString(const std::string& input) {
  39   // RFC 959 only allows ASCII strings, but at least Firefox can send non-ASCII
  40   // characters in the command if the request path contains them. To be
  41   // compatible, we do the same and allow non-ASCII characters in a command.
  42
  43   // Protect agains newline injection attack.
  44   if (input.find_first_of("\r\n") != std::string::npos)
  45     return false;
  46
  47   return true;
  48 }
  49
  50 enum ErrorClass {
  51   // The requested action was initiated. The client should expect another
  52   // reply before issuing the next command.
  53   ERROR_CLASS_INITIATED,
  54
  55   // The requested action has been successfully completed.
  56   ERROR_CLASS_OK,
  57
  58   // The command has been accepted, but to complete the operation, more
  59   // information must be sent by the client.
  60   ERROR_CLASS_INFO_NEEDED,
  61
  62   // The command was not accepted and the requested action did not take place.
  63   // This condition is temporary, and the client is encouraged to restart the
  64   // command sequence.
  65   ERROR_CLASS_TRANSIENT_ERROR,
  66
  67   // The command was not accepted and the requested action did not take place.
  68   // This condition is rather permanent, and the client is discouraged from
  69   // repeating the exact request.
  70   ERROR_CLASS_PERMANENT_ERROR,
  71 };
  72
  73 // Returns the error class for given response code. Caller should ensure
  74 // that |response_code| is in range 100-599.
  75 ErrorClass GetErrorClass(int response_code) {
  76   if (response_code >= 100 && response_code <= 199)
  77     return ERROR_CLASS_INITIATED;
  78
  79   if (response_code >= 200 && response_code <= 299)
  80     return ERROR_CLASS_OK;
  81
  82   if (response_code >= 300 && response_code <= 399)
  83     return ERROR_CLASS_INFO_NEEDED;
  84
  85   if (response_code >= 400 && response_code <= 499)
  86     return ERROR_CLASS_TRANSIENT_ERROR;
  87
  88   if (response_code >= 500 && response_code <= 599)
  89     return ERROR_CLASS_PERMANENT_ERROR;
  90
  91   // We should not be called on invalid error codes.
  92   NOTREACHED() << response_code;
  93   return ERROR_CLASS_PERMANENT_ERROR;
  94 }
  95
  96 // Returns network error code for received FTP |response_code|.
  97 int GetNetErrorCodeForFtpResponseCode(int response_code) {
  98   switch (response_code) {
  99     case 421:
 100       return ERR_FTP_SERVICE_UNAVAILABLE;
 101     case 426:
 102       return ERR_FTP_TRANSFER_ABORTED;
 103     case 450:
 104       return ERR_FTP_FILE_BUSY;
 105     case 500:
 106     case 501:
 107       return ERR_FTP_SYNTAX_ERROR;
 108     case 502:
 109     case 504:
 110       return ERR_FTP_COMMAND_NOT_SUPPORTED;
 111     case 503:
 112       return ERR_FTP_BAD_COMMAND_SEQUENCE;
 113     default:
 114       return ERR_FTP_FAILED;
 115   }
 116 }
 117
 118 // From RFC 2428 Section 3:
 119 //   The text returned in response to the EPSV command MUST be:
 120 //     <some text> (<d><d><d><tcp-port><d>)
 121 //   <d> is a delimiter character, ideally to be |
 122 bool ExtractPortFromEPSVResponse(const FtpCtrlResponse& response, int* port) {
 123   if (response.lines.size() != 1)
 124     return false;
 125   const char* ptr = response.lines[0].c_str();
 126   while (*ptr && *ptr != '(')
 127     ++ptr;
 128   if (!*ptr)
 129     return false;
 130   char sep = *(++ptr);
 131   if (!sep || isdigit(sep) || *(++ptr) != sep || *(++ptr) != sep)
 132     return false;
 133   if (!isdigit(*(++ptr)))
 134     return false;
 135   *port = *ptr - '0';
 136   while (isdigit(*(++ptr))) {
 137     *port *= 10;
 138     *port += *ptr - '0';
 139   }
 140   if (*ptr != sep)
 141     return false;
 142
 143   return true;
 144 }
 145
 146 // There are two way we can receive IP address and port.
 147 // (127,0,0,1,23,21) IP address and port encapsulated in ().
 148 // 127,0,0,1,23,21  IP address and port without ().
 149 //
 150 // See RFC 959, Section 4.1.2
 151 bool ExtractPortFromPASVResponse(const FtpCtrlResponse& response, int* port) {
 152   if (response.lines.size() != 1)
 153     return false;
 154
 155   std::string line(response.lines[0]);
 156   if (!base::IsStringASCII(line))
 157     return false;
 158   if (line.length() < 2)
 159     return false;
 160
 161   size_t paren_pos = line.find('(');
 162   if (paren_pos == std::string::npos) {
 163     // Find the first comma and use it to locate the beginning
 164     // of the response data.
 165     size_t comma_pos = line.find(',');
 166     if (comma_pos == std::string::npos)
 167       return false;
 168
 169     size_t space_pos = line.rfind(' ', comma_pos);
 170     if (space_pos != std::string::npos)
 171       line = line.substr(space_pos + 1);
 172   } else {
 173     // Remove the parentheses and use the text inside them.
 174     size_t closing_paren_pos = line.rfind(')');
 175     if (closing_paren_pos == std::string::npos)
 176       return false;
 177     if (closing_paren_pos <= paren_pos)
 178       return false;
 179
 180     line = line.substr(paren_pos + 1, closing_paren_pos - paren_pos - 1);
 181   }
 182
 183   // Split the line into comma-separated pieces and extract
 184   // the last two.
 185   std::vector<base::StringPiece> pieces = base::SplitStringPiece(
 186       line, ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
 187   if (pieces.size() != 6)
 188     return false;
 189
 190   // Ignore the IP address supplied in the response. We are always going
 191   // to connect back to the same server to prevent FTP PASV port scanning.
 192   int p0, p1;
 193   if (!base::StringToInt(pieces[4], &p0))
 194     return false;
 195   if (!base::StringToInt(pieces[5], &p1))
 196     return false;
 197   *port = (p0 << 8) + p1;
 198
 199   return true;
 200 }
 201
 202 }  // namespace
 203
 204 FtpNetworkTransaction::FtpNetworkTransaction(
 205     HostResolver* resolver,
 206     ClientSocketFactory* socket_factory)
 207     : command_sent_(COMMAND_NONE),
 208       io_callback_(base::Bind(&FtpNetworkTransaction::OnIOComplete,
 209                               base::Unretained(this))),
 210       request_(NULL),
 211       resolver_(resolver),
 212       read_ctrl_buf_(new IOBuffer(kCtrlBufLen)),
 213       read_data_buf_len_(0),
 214       last_error_(OK),
 215       system_type_(SYSTEM_TYPE_UNKNOWN),
 216       // Use image (binary) transfer by default. It should always work,
 217       // whereas the ascii transfer may damage binary data.
 218       data_type_(DATA_TYPE_IMAGE),
 219       resource_type_(RESOURCE_TYPE_UNKNOWN),
 220       use_epsv_(true),
 221       data_connection_port_(0),
 222       socket_factory_(socket_factory),
 223       next_state_(STATE_NONE),
 224       state_after_data_connect_complete_(STATE_NONE) {
 225 }
 226
 227 FtpNetworkTransaction::~FtpNetworkTransaction() {
 228 }
 229
 230 int FtpNetworkTransaction::Stop(int error) {
 231   if (command_sent_ == COMMAND_QUIT)
 232     return error;
 233
 234   next_state_ = STATE_CTRL_WRITE_QUIT;
 235   last_error_ = error;
 236   return OK;
 237 }
 238
 239 int FtpNetworkTransaction::Start(const FtpRequestInfo* request_info,
 240                                  const CompletionCallback& callback,
 241                                  const BoundNetLog& net_log) {
 242   net_log_ = net_log;
 243   request_ = request_info;
 244
 245   ctrl_response_buffer_.reset(new FtpCtrlResponseBuffer(net_log_));
 246
 247   if (request_->url.has_username()) {
 248     base::string16 username;
 249     base::string16 password;
 250     GetIdentityFromURL(request_->url, &username, &password);
 251     credentials_.Set(username, password);
 252   } else {
 253     credentials_.Set(base::ASCIIToUTF16("anonymous"),
 254                      base::ASCIIToUTF16("chrome@example.com"));
 255   }
 256
 257   DetectTypecode();
 258
 259   next_state_ = STATE_CTRL_RESOLVE_HOST;
 260   int rv = DoLoop(OK);
 261   if (rv == ERR_IO_PENDING)
 262     user_callback_ = callback;
 263   return rv;
 264 }
 265
 266 int FtpNetworkTransaction::RestartWithAuth(const AuthCredentials& credentials,
 267                                            const CompletionCallback& callback) {
 268   ResetStateForRestart();
 269
 270   credentials_ = credentials;
 271
 272   next_state_ = STATE_CTRL_RESOLVE_HOST;
 273   int rv = DoLoop(OK);
 274   if (rv == ERR_IO_PENDING)
 275     user_callback_ = callback;
 276   return rv;
 277 }
 278
 279 int FtpNetworkTransaction::Read(IOBuffer* buf,
 280                                 int buf_len,
 281                                 const CompletionCallback& callback) {
 282   DCHECK(buf);
 283   DCHECK_GT(buf_len, 0);
 284
 285   read_data_buf_ = buf;
 286   read_data_buf_len_ = buf_len;
 287
 288   next_state_ = STATE_DATA_READ;
 289   int rv = DoLoop(OK);
 290   if (rv == ERR_IO_PENDING)
 291     user_callback_ = callback;
 292   return rv;
 293 }
 294
 295 const FtpResponseInfo* FtpNetworkTransaction::GetResponseInfo() const {
 296   return &response_;
 297 }
 298
 299 LoadState FtpNetworkTransaction::GetLoadState() const {
 300   if (next_state_ == STATE_CTRL_RESOLVE_HOST_COMPLETE)
 301     return LOAD_STATE_RESOLVING_HOST;
 302
 303   if (next_state_ == STATE_CTRL_CONNECT_COMPLETE ||
 304       next_state_ == STATE_DATA_CONNECT_COMPLETE)
 305     return LOAD_STATE_CONNECTING;
 306
 307   if (next_state_ == STATE_DATA_READ_COMPLETE)
 308     return LOAD_STATE_READING_RESPONSE;
 309
 310   if (command_sent_ == COMMAND_RETR && read_data_buf_.get())
 311     return LOAD_STATE_READING_RESPONSE;
 312
 313   if (command_sent_ == COMMAND_QUIT)
 314     return LOAD_STATE_IDLE;
 315
 316   if (command_sent_ != COMMAND_NONE)
 317     return LOAD_STATE_SENDING_REQUEST;
 318
 319   return LOAD_STATE_IDLE;
 320 }
 321
 322 uint64 FtpNetworkTransaction::GetUploadProgress() const {
 323   return 0;
 324 }
 325
 326 void FtpNetworkTransaction::ResetStateForRestart() {
 327   command_sent_ = COMMAND_NONE;
 328   user_callback_.Reset();
 329   response_ = FtpResponseInfo();
 330   read_ctrl_buf_ = new IOBuffer(kCtrlBufLen);
 331   ctrl_response_buffer_.reset(new FtpCtrlResponseBuffer(net_log_));
 332   read_data_buf_ = NULL;
 333   read_data_buf_len_ = 0;
 334   if (write_buf_.get())
 335     write_buf_->SetOffset(0);
 336   last_error_ = OK;
 337   data_connection_port_ = 0;
 338   ctrl_socket_.reset();
 339   data_socket_.reset();
 340   next_state_ = STATE_NONE;
 341   state_after_data_connect_complete_ = STATE_NONE;
 342 }
 343
 344 void FtpNetworkTransaction::EstablishDataConnection(State state_after_connect) {
 345   DCHECK(state_after_connect == STATE_CTRL_WRITE_RETR ||
 346          state_after_connect == STATE_CTRL_WRITE_LIST);
 347   state_after_data_connect_complete_ = state_after_connect;
 348   next_state_ = use_epsv_ ? STATE_CTRL_WRITE_EPSV : STATE_CTRL_WRITE_PASV;
 349 }
 350
 351 void FtpNetworkTransaction::DoCallback(int rv) {
 352   DCHECK(rv != ERR_IO_PENDING);
 353   DCHECK(!user_callback_.is_null());
 354
 355   // Since Run may result in Read being called, clear callback_ up front.
 356   CompletionCallback c = user_callback_;
 357   user_callback_.Reset();
 358   c.Run(rv);
 359 }
 360
 361 void FtpNetworkTransaction::OnIOComplete(int result) {
 362   int rv = DoLoop(result);
 363   if (rv != ERR_IO_PENDING)
 364     DoCallback(rv);
 365 }
 366
 367 int FtpNetworkTransaction::ProcessCtrlResponse() {
 368   FtpCtrlResponse response = ctrl_response_buffer_->PopResponse();
 369
 370   int rv = OK;
 371   switch (command_sent_) {
 372     case COMMAND_NONE:
 373       // TODO(phajdan.jr): Check for errors in the welcome message.
 374       next_state_ = STATE_CTRL_WRITE_USER;
 375       break;
 376     case COMMAND_USER:
 377       rv = ProcessResponseUSER(response);
 378       break;
 379     case COMMAND_PASS:
 380       rv = ProcessResponsePASS(response);
 381       break;
 382     case COMMAND_SYST:
 383       rv = ProcessResponseSYST(response);
 384       break;
 385     case COMMAND_PWD:
 386       rv = ProcessResponsePWD(response);
 387       break;
 388     case COMMAND_TYPE:
 389       rv = ProcessResponseTYPE(response);
 390       break;
 391     case COMMAND_EPSV:
 392       rv = ProcessResponseEPSV(response);
 393       break;
 394     case COMMAND_PASV:
 395       rv = ProcessResponsePASV(response);
 396       break;
 397     case COMMAND_SIZE:
 398       rv = ProcessResponseSIZE(response);
 399       break;
 400     case COMMAND_RETR:
 401       rv = ProcessResponseRETR(response);
 402       break;
 403     case COMMAND_CWD:
 404       rv = ProcessResponseCWD(response);
 405       break;
 406     case COMMAND_LIST:
 407       rv = ProcessResponseLIST(response);
 408       break;
 409     case COMMAND_QUIT:
 410       rv = ProcessResponseQUIT(response);
 411       break;
 412     default:
 413       LOG(DFATAL) << "Unexpected value of command_sent_: " << command_sent_;
 414       return ERR_UNEXPECTED;
 415   }
 416
 417   // We may get multiple responses for some commands,
 418   // see http://crbug.com/18036.
 419   while (ctrl_response_buffer_->ResponseAvailable() && rv == OK) {
 420     response = ctrl_response_buffer_->PopResponse();
 421
 422     switch (command_sent_) {
 423       case COMMAND_RETR:
 424         rv = ProcessResponseRETR(response);
 425         break;
 426       case COMMAND_LIST:
 427         rv = ProcessResponseLIST(response);
 428         break;
 429       default:
 430         // Multiple responses for other commands are invalid.
 431         return Stop(ERR_INVALID_RESPONSE);
 432     }
 433   }
 434
 435   return rv;
 436 }
 437
 438 // Used to prepare and send FTP command.
 439 int FtpNetworkTransaction::SendFtpCommand(const std::string& command,
 440                                           const std::string& command_for_log,
 441                                           Command cmd) {
 442   // If we send a new command when we still have unprocessed responses
 443   // for previous commands, the response receiving code will have no way to know
 444   // which responses are for which command.
 445   DCHECK(!ctrl_response_buffer_->ResponseAvailable());
 446
 447   DCHECK(!write_command_buf_.get());
 448   DCHECK(!write_buf_.get());
 449
 450   if (!IsValidFTPCommandString(command)) {
 451     // Callers should validate the command themselves and return a more specific
 452     // error code.
 453     NOTREACHED();
 454     return Stop(ERR_UNEXPECTED);
 455   }
 456
 457   command_sent_ = cmd;
 458
 459   write_command_buf_ = new IOBufferWithSize(command.length() + 2);
 460   write_buf_ = new DrainableIOBuffer(write_command_buf_.get(),
 461                                      write_command_buf_->size());
 462   memcpy(write_command_buf_->data(), command.data(), command.length());
 463   memcpy(write_command_buf_->data() + command.length(), kCRLF, 2);
 464
 465   net_log_.AddEvent(NetLog::TYPE_FTP_COMMAND_SENT,
 466                     NetLog::StringCallback("command", &command_for_log));
 467
 468   next_state_ = STATE_CTRL_WRITE;
 469   return OK;
 470 }
 471
 472 std::string FtpNetworkTransaction::GetRequestPathForFtpCommand(
 473     bool is_directory) const {
 474   std::string path(current_remote_directory_);
 475   if (request_->url.has_path()) {
 476     std::string gurl_path(request_->url.path());
 477
 478     // Get rid of the typecode, see RFC 1738 section 3.2.2. FTP url-path.
 479     std::string::size_type pos = gurl_path.rfind(';');
 480     if (pos != std::string::npos)
 481       gurl_path.resize(pos);
 482
 483     path.append(gurl_path);
 484   }
 485   // Make sure that if the path is expected to be a file, it won't end
 486   // with a trailing slash.
 487   if (!is_directory && path.length() > 1 && path[path.length() - 1] == '/')
 488     path.erase(path.length() - 1);
 489   UnescapeRule::Type unescape_rules = UnescapeRule::SPACES |
 490                                       UnescapeRule::URL_SPECIAL_CHARS;
 491   // This may unescape to non-ASCII characters, but we allow that. See the
 492   // comment for IsValidFTPCommandString.
 493   path = UnescapeURLComponent(path, unescape_rules);
 494
 495   if (system_type_ == SYSTEM_TYPE_VMS) {
 496     if (is_directory)
 497       path = FtpUtil::UnixDirectoryPathToVMS(path);
 498     else
 499       path = FtpUtil::UnixFilePathToVMS(path);
 500   }
 501
 502   DCHECK(IsValidFTPCommandString(path));
 503   return path;
 504 }
 505
 506 void FtpNetworkTransaction::DetectTypecode() {
 507   if (!request_->url.has_path())
 508     return;
 509   std::string gurl_path(request_->url.path());
 510
 511   // Extract the typecode, see RFC 1738 section 3.2.2. FTP url-path.
 512   std::string::size_type pos = gurl_path.rfind(';');
 513   if (pos == std::string::npos)
 514     return;
 515   std::string typecode_string(gurl_path.substr(pos));
 516   if (typecode_string == ";type=a") {
 517     data_type_ = DATA_TYPE_ASCII;
 518     resource_type_ = RESOURCE_TYPE_FILE;
 519   } else if (typecode_string == ";type=i") {
 520     data_type_ = DATA_TYPE_IMAGE;
 521     resource_type_ = RESOURCE_TYPE_FILE;
 522   } else if (typecode_string == ";type=d") {
 523     resource_type_ = RESOURCE_TYPE_DIRECTORY;
 524   }
 525 }
 526
 527 int FtpNetworkTransaction::DoLoop(int result) {
 528   DCHECK(next_state_ != STATE_NONE);
 529
 530   int rv = result;
 531   do {
 532     State state = next_state_;
 533     next_state_ = STATE_NONE;
 534     switch (state) {
 535       case STATE_CTRL_RESOLVE_HOST:
 536         DCHECK(rv == OK);
 537         rv = DoCtrlResolveHost();
 538         break;
 539       case STATE_CTRL_RESOLVE_HOST_COMPLETE:
 540         rv = DoCtrlResolveHostComplete(rv);
 541         break;
 542       case STATE_CTRL_CONNECT:
 543         DCHECK(rv == OK);
 544         rv = DoCtrlConnect();
 545         break;
 546       case STATE_CTRL_CONNECT_COMPLETE:
 547         rv = DoCtrlConnectComplete(rv);
 548         break;
 549       case STATE_CTRL_READ:
 550         DCHECK(rv == OK);
 551         rv = DoCtrlRead();
 552         break;
 553       case STATE_CTRL_READ_COMPLETE:
 554         rv = DoCtrlReadComplete(rv);
 555         break;
 556       case STATE_CTRL_WRITE:
 557         DCHECK(rv == OK);
 558         rv = DoCtrlWrite();
 559         break;
 560       case STATE_CTRL_WRITE_COMPLETE:
 561         rv = DoCtrlWriteComplete(rv);
 562         break;
 563       case STATE_CTRL_WRITE_USER:
 564         DCHECK(rv == OK);
 565         rv = DoCtrlWriteUSER();
 566         break;
 567       case STATE_CTRL_WRITE_PASS:
 568         DCHECK(rv == OK);
 569         rv = DoCtrlWritePASS();
 570         break;
 571       case STATE_CTRL_WRITE_SYST:
 572         DCHECK(rv == OK);
 573         rv = DoCtrlWriteSYST();
 574         break;
 575       case STATE_CTRL_WRITE_PWD:
 576         DCHECK(rv == OK);
 577         rv = DoCtrlWritePWD();
 578         break;
 579       case STATE_CTRL_WRITE_TYPE:
 580         DCHECK(rv == OK);
 581         rv = DoCtrlWriteTYPE();
 582         break;
 583       case STATE_CTRL_WRITE_EPSV:
 584         DCHECK(rv == OK);
 585         rv = DoCtrlWriteEPSV();
 586         break;
 587       case STATE_CTRL_WRITE_PASV:
 588         DCHECK(rv == OK);
 589         rv = DoCtrlWritePASV();
 590         break;
 591       case STATE_CTRL_WRITE_RETR:
 592         DCHECK(rv == OK);
 593         rv = DoCtrlWriteRETR();
 594         break;
 595       case STATE_CTRL_WRITE_SIZE:
 596         DCHECK(rv == OK);
 597         rv = DoCtrlWriteSIZE();
 598         break;
 599       case STATE_CTRL_WRITE_CWD:
 600         DCHECK(rv == OK);
 601         rv = DoCtrlWriteCWD();
 602         break;
 603       case STATE_CTRL_WRITE_LIST:
 604         DCHECK(rv == OK);
 605         rv = DoCtrlWriteLIST();
 606         break;
 607       case STATE_CTRL_WRITE_QUIT:
 608         DCHECK(rv == OK);
 609         rv = DoCtrlWriteQUIT();
 610         break;
 611       case STATE_DATA_CONNECT:
 612         DCHECK(rv == OK);
 613         rv = DoDataConnect();
 614         break;
 615       case STATE_DATA_CONNECT_COMPLETE:
 616         rv = DoDataConnectComplete(rv);
 617         break;
 618       case STATE_DATA_READ:
 619         DCHECK(rv == OK);
 620         rv = DoDataRead();
 621         break;
 622       case STATE_DATA_READ_COMPLETE:
 623         rv = DoDataReadComplete(rv);
 624         break;
 625       default:
 626         NOTREACHED() << "bad state";
 627         rv = ERR_UNEXPECTED;
 628         break;
 629     }
 630   } while (rv != ERR_IO_PENDING && next_state_ != STATE_NONE);
 631   return rv;
 632 }
 633
 634 int FtpNetworkTransaction::DoCtrlResolveHost() {
 635   next_state_ = STATE_CTRL_RESOLVE_HOST_COMPLETE;
 636
 637   HostResolver::RequestInfo info(HostPortPair::FromURL(request_->url));
 638   // No known referrer.
 639   return resolver_.Resolve(
 640       info,
 641       DEFAULT_PRIORITY,
 642       &addresses_,
 643       base::Bind(&FtpNetworkTransaction::OnIOComplete, base::Unretained(this)),
 644       net_log_);
 645 }
 646
 647 int FtpNetworkTransaction::DoCtrlResolveHostComplete(int result) {
 648   if (result == OK)
 649     next_state_ = STATE_CTRL_CONNECT;
 650   return result;
 651 }
 652
 653 int FtpNetworkTransaction::DoCtrlConnect() {
 654   next_state_ = STATE_CTRL_CONNECT_COMPLETE;
 655   ctrl_socket_ = socket_factory_->CreateTransportClientSocket(
 656       addresses_, net_log_.net_log(), net_log_.source());
 657   net_log_.AddEvent(
 658       NetLog::TYPE_FTP_CONTROL_CONNECTION,
 659       ctrl_socket_->NetLog().source().ToEventParametersCallback());
 660   return ctrl_socket_->Connect(io_callback_);
 661 }
 662
 663 int FtpNetworkTransaction::DoCtrlConnectComplete(int result) {
 664   if (result == OK) {
 665     // Put the peer's IP address and port into the response.
 666     IPEndPoint ip_endpoint;
 667     result = ctrl_socket_->GetPeerAddress(&ip_endpoint);
 668     if (result == OK) {
 669       response_.socket_address = HostPortPair::FromIPEndPoint(ip_endpoint);
 670       next_state_ = STATE_CTRL_READ;
 671
 672       if (ip_endpoint.GetFamily() == ADDRESS_FAMILY_IPV4) {
 673         // Do not use EPSV for IPv4 connections. Some servers become confused
 674         // and we time out while waiting to connect. PASV is perfectly fine for
 675         // IPv4. Note that this blacklists IPv4 not to use EPSV instead of
 676         // whitelisting IPv6 to use it, to make the code more future-proof:
 677         // all future protocols should just use EPSV.
 678         use_epsv_ = false;
 679       }
 680     }
 681   }
 682   return result;
 683 }
 684
 685 int FtpNetworkTransaction::DoCtrlRead() {
 686   next_state_ = STATE_CTRL_READ_COMPLETE;
 687   return ctrl_socket_->Read(read_ctrl_buf_.get(), kCtrlBufLen, io_callback_);
 688 }
 689
 690 int FtpNetworkTransaction::DoCtrlReadComplete(int result) {
 691   if (result == 0) {
 692     // Some servers (for example Pure-FTPd) apparently close the control
 693     // connection when anonymous login is not permitted. For more details
 694     // see http://crbug.com/25023.
 695     if (command_sent_ == COMMAND_USER &&
 696         credentials_.username() == base::ASCIIToUTF16("anonymous")) {
 697       response_.needs_auth = true;
 698     }
 699     return Stop(ERR_EMPTY_RESPONSE);
 700   }
 701   if (result < 0)
 702     return Stop(result);
 703
 704   ctrl_response_buffer_->ConsumeData(read_ctrl_buf_->data(), result);
 705
 706   if (!ctrl_response_buffer_->ResponseAvailable()) {
 707     // Read more data from the control socket.
 708     next_state_ = STATE_CTRL_READ;
 709     return OK;
 710   }
 711
 712   return ProcessCtrlResponse();
 713 }
 714
 715 int FtpNetworkTransaction::DoCtrlWrite() {
 716   next_state_ = STATE_CTRL_WRITE_COMPLETE;
 717
 718   return ctrl_socket_->Write(
 719       write_buf_.get(), write_buf_->BytesRemaining(), io_callback_);
 720 }
 721
 722 int FtpNetworkTransaction::DoCtrlWriteComplete(int result) {
 723   if (result < 0)
 724     return result;
 725
 726   write_buf_->DidConsume(result);
 727   if (write_buf_->BytesRemaining() == 0) {
 728     // Clear the write buffer.
 729     write_buf_ = NULL;
 730     write_command_buf_ = NULL;
 731
 732     next_state_ = STATE_CTRL_READ;
 733   } else {
 734     next_state_ = STATE_CTRL_WRITE;
 735   }
 736   return OK;
 737 }
 738
 739 // FTP Commands and responses
 740
 741 // USER Command.
 742 int FtpNetworkTransaction::DoCtrlWriteUSER() {
 743   std::string command = "USER " + base::UTF16ToUTF8(credentials_.username());
 744
 745   if (!IsValidFTPCommandString(command))
 746     return Stop(ERR_MALFORMED_IDENTITY);
 747
 748   next_state_ = STATE_CTRL_READ;
 749   return SendFtpCommand(command, "USER ***", COMMAND_USER);
 750 }
 751
 752 int FtpNetworkTransaction::ProcessResponseUSER(
 753     const FtpCtrlResponse& response) {
 754   switch (GetErrorClass(response.status_code)) {
 755     case ERROR_CLASS_OK:
 756       next_state_ = STATE_CTRL_WRITE_SYST;
 757       break;
 758     case ERROR_CLASS_INFO_NEEDED:
 759       next_state_ = STATE_CTRL_WRITE_PASS;
 760       break;
 761     case ERROR_CLASS_TRANSIENT_ERROR:
 762     case ERROR_CLASS_PERMANENT_ERROR:
 763       response_.needs_auth = true;
 764       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 765     default:
 766       NOTREACHED();
 767       return Stop(ERR_UNEXPECTED);
 768   }
 769   return OK;
 770 }
 771
 772 // PASS command.
 773 int FtpNetworkTransaction::DoCtrlWritePASS() {
 774   std::string command = "PASS " + base::UTF16ToUTF8(credentials_.password());
 775
 776   if (!IsValidFTPCommandString(command))
 777     return Stop(ERR_MALFORMED_IDENTITY);
 778
 779   next_state_ = STATE_CTRL_READ;
 780   return SendFtpCommand(command, "PASS ***", COMMAND_PASS);
 781 }
 782
 783 int FtpNetworkTransaction::ProcessResponsePASS(
 784     const FtpCtrlResponse& response) {
 785   switch (GetErrorClass(response.status_code)) {
 786     case ERROR_CLASS_OK:
 787       next_state_ = STATE_CTRL_WRITE_SYST;
 788       break;
 789     case ERROR_CLASS_INFO_NEEDED:
 790       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 791     case ERROR_CLASS_TRANSIENT_ERROR:
 792     case ERROR_CLASS_PERMANENT_ERROR:
 793       response_.needs_auth = true;
 794       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 795     default:
 796       NOTREACHED();
 797       return Stop(ERR_UNEXPECTED);
 798   }
 799   return OK;
 800 }
 801
 802 // SYST command.
 803 int FtpNetworkTransaction::DoCtrlWriteSYST() {
 804   std::string command = "SYST";
 805   next_state_ = STATE_CTRL_READ;
 806   return SendFtpCommand(command, command, COMMAND_SYST);
 807 }
 808
 809 int FtpNetworkTransaction::ProcessResponseSYST(
 810     const FtpCtrlResponse& response) {
 811   switch (GetErrorClass(response.status_code)) {
 812     case ERROR_CLASS_INITIATED:
 813       return Stop(ERR_INVALID_RESPONSE);
 814     case ERROR_CLASS_OK: {
 815       // All important info should be on the first line.
 816       std::string line = response.lines[0];
 817       // The response should be ASCII, which allows us to do case-insensitive
 818       // comparisons easily. If it is not ASCII, we leave the system type
 819       // as unknown.
 820       if (base::IsStringASCII(line)) {
 821         line = base::ToLowerASCII(line);
 822
 823         // Remove all whitespace, to correctly handle cases like fancy "V M S"
 824         // response instead of "VMS".
 825         base::RemoveChars(line, base::kWhitespaceASCII, &line);
 826
 827         // The "magic" strings we test for below have been gathered by an
 828         // empirical study. VMS needs to come first because some VMS systems
 829         // also respond with "UNIX emulation", which is not perfect. It is much
 830         // more reliable to talk to these servers in their native language.
 831         if (line.find("vms") != std::string::npos) {
 832           system_type_ = SYSTEM_TYPE_VMS;
 833         } else if (line.find("l8") != std::string::npos ||
 834                    line.find("unix") != std::string::npos ||
 835                    line.find("bsd") != std::string::npos) {
 836           system_type_ = SYSTEM_TYPE_UNIX;
 837         } else if (line.find("win32") != std::string::npos ||
 838                    line.find("windows") != std::string::npos) {
 839           system_type_ = SYSTEM_TYPE_WINDOWS;
 840         } else if (line.find("os/2") != std::string::npos) {
 841           system_type_ = SYSTEM_TYPE_OS2;
 842         }
 843       }
 844       next_state_ = STATE_CTRL_WRITE_PWD;
 845       break;
 846     }
 847     case ERROR_CLASS_INFO_NEEDED:
 848       return Stop(ERR_INVALID_RESPONSE);
 849     case ERROR_CLASS_TRANSIENT_ERROR:
 850       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 851     case ERROR_CLASS_PERMANENT_ERROR:
 852       // Server does not recognize the SYST command so proceed.
 853       next_state_ = STATE_CTRL_WRITE_PWD;
 854       break;
 855     default:
 856       NOTREACHED();
 857       return Stop(ERR_UNEXPECTED);
 858   }
 859   return OK;
 860 }
 861
 862 // PWD command.
 863 int FtpNetworkTransaction::DoCtrlWritePWD() {
 864   std::string command = "PWD";
 865   next_state_ = STATE_CTRL_READ;
 866   return SendFtpCommand(command, command, COMMAND_PWD);
 867 }
 868
 869 int FtpNetworkTransaction::ProcessResponsePWD(const FtpCtrlResponse& response) {
 870   switch (GetErrorClass(response.status_code)) {
 871     case ERROR_CLASS_INITIATED:
 872       return Stop(ERR_INVALID_RESPONSE);
 873     case ERROR_CLASS_OK: {
 874       // The info we look for should be on the first line.
 875       std::string line = response.lines[0];
 876       if (line.empty())
 877         return Stop(ERR_INVALID_RESPONSE);
 878       std::string::size_type quote_pos = line.find('"');
 879       if (quote_pos != std::string::npos) {
 880         line = line.substr(quote_pos + 1);
 881         quote_pos = line.find('"');
 882         if (quote_pos == std::string::npos)
 883           return Stop(ERR_INVALID_RESPONSE);
 884         line = line.substr(0, quote_pos);
 885       }
 886       if (system_type_ == SYSTEM_TYPE_VMS)
 887         line = FtpUtil::VMSPathToUnix(line);
 888       if (line.length() && line[line.length() - 1] == '/')
 889         line.erase(line.length() - 1);
 890       current_remote_directory_ = line;
 891       next_state_ = STATE_CTRL_WRITE_TYPE;
 892       break;
 893     }
 894     case ERROR_CLASS_INFO_NEEDED:
 895       return Stop(ERR_INVALID_RESPONSE);
 896     case ERROR_CLASS_TRANSIENT_ERROR:
 897       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 898     case ERROR_CLASS_PERMANENT_ERROR:
 899       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 900     default:
 901       NOTREACHED();
 902       return Stop(ERR_UNEXPECTED);
 903   }
 904   return OK;
 905 }
 906
 907 // TYPE command.
 908 int FtpNetworkTransaction::DoCtrlWriteTYPE() {
 909   std::string command = "TYPE ";
 910   if (data_type_ == DATA_TYPE_ASCII) {
 911     command += "A";
 912   } else if (data_type_ == DATA_TYPE_IMAGE) {
 913     command += "I";
 914   } else {
 915     NOTREACHED();
 916     return Stop(ERR_UNEXPECTED);
 917   }
 918   next_state_ = STATE_CTRL_READ;
 919   return SendFtpCommand(command, command, COMMAND_TYPE);
 920 }
 921
 922 int FtpNetworkTransaction::ProcessResponseTYPE(
 923     const FtpCtrlResponse& response) {
 924   switch (GetErrorClass(response.status_code)) {
 925     case ERROR_CLASS_INITIATED:
 926       return Stop(ERR_INVALID_RESPONSE);
 927     case ERROR_CLASS_OK:
 928       next_state_ = STATE_CTRL_WRITE_SIZE;
 929       break;
 930     case ERROR_CLASS_INFO_NEEDED:
 931       return Stop(ERR_INVALID_RESPONSE);
 932     case ERROR_CLASS_TRANSIENT_ERROR:
 933       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 934     case ERROR_CLASS_PERMANENT_ERROR:
 935       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 936     default:
 937       NOTREACHED();
 938       return Stop(ERR_UNEXPECTED);
 939   }
 940   return OK;
 941 }
 942
 943 // EPSV command
 944 int FtpNetworkTransaction::DoCtrlWriteEPSV() {
 945   const std::string command = "EPSV";
 946   next_state_ = STATE_CTRL_READ;
 947   return SendFtpCommand(command, command, COMMAND_EPSV);
 948 }
 949
 950 int FtpNetworkTransaction::ProcessResponseEPSV(
 951     const FtpCtrlResponse& response) {
 952   switch (GetErrorClass(response.status_code)) {
 953     case ERROR_CLASS_INITIATED:
 954       return Stop(ERR_INVALID_RESPONSE);
 955     case ERROR_CLASS_OK: {
 956       int port;
 957       if (!ExtractPortFromEPSVResponse(response, &port))
 958         return Stop(ERR_INVALID_RESPONSE);
 959       if (IsWellKnownPort(port) ||
 960           !IsPortAllowedForScheme(port, url::kFtpScheme)) {
 961         return Stop(ERR_UNSAFE_PORT);
 962       }
 963       data_connection_port_ = static_cast<uint16>(port);
 964       next_state_ = STATE_DATA_CONNECT;
 965       break;
 966     }
 967     case ERROR_CLASS_INFO_NEEDED:
 968       return Stop(ERR_INVALID_RESPONSE);
 969     case ERROR_CLASS_TRANSIENT_ERROR:
 970     case ERROR_CLASS_PERMANENT_ERROR:
 971       use_epsv_ = false;
 972       next_state_ = STATE_CTRL_WRITE_PASV;
 973       return OK;
 974     default:
 975       NOTREACHED();
 976       return Stop(ERR_UNEXPECTED);
 977   }
 978   return OK;
 979 }
 980
 981 // PASV command
 982 int FtpNetworkTransaction::DoCtrlWritePASV() {
 983   std::string command = "PASV";
 984   next_state_ = STATE_CTRL_READ;
 985   return SendFtpCommand(command, command, COMMAND_PASV);
 986 }
 987
 988 int FtpNetworkTransaction::ProcessResponsePASV(
 989     const FtpCtrlResponse& response) {
 990   switch (GetErrorClass(response.status_code)) {
 991     case ERROR_CLASS_INITIATED:
 992       return Stop(ERR_INVALID_RESPONSE);
 993     case ERROR_CLASS_OK: {
 994       int port;
 995       if (!ExtractPortFromPASVResponse(response, &port))
 996         return Stop(ERR_INVALID_RESPONSE);
 997       if (IsWellKnownPort(port) ||
 998           !IsPortAllowedForScheme(port, url::kFtpScheme)) {
 999         return Stop(ERR_UNSAFE_PORT);
1000       }
1001       data_connection_port_ = static_cast<uint16>(port);
1002       next_state_ = STATE_DATA_CONNECT;
1003       break;
1004     }
1005     case ERROR_CLASS_INFO_NEEDED:
1006       return Stop(ERR_INVALID_RESPONSE);
1007     case ERROR_CLASS_TRANSIENT_ERROR:
1008       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1009     case ERROR_CLASS_PERMANENT_ERROR:
1010       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1011     default:
1012       NOTREACHED();
1013       return Stop(ERR_UNEXPECTED);
1014   }
1015   return OK;
1016 }
1017
1018 // RETR command
1019 int FtpNetworkTransaction::DoCtrlWriteRETR() {
1020   std::string command = "RETR " + GetRequestPathForFtpCommand(false);
1021   next_state_ = STATE_CTRL_READ;
1022   return SendFtpCommand(command, command, COMMAND_RETR);
1023 }
1024
1025 int FtpNetworkTransaction::ProcessResponseRETR(
1026     const FtpCtrlResponse& response) {
1027   // Resource type should be either filled in by DetectTypecode() or
1028   // detected with CWD. RETR is sent only when the resource is a file.
1029   DCHECK_EQ(RESOURCE_TYPE_FILE, resource_type_);
1030
1031   switch (GetErrorClass(response.status_code)) {
1032     case ERROR_CLASS_INITIATED:
1033       // We want the client to start reading the response at this point.
1034       // It got here either through Start or RestartWithAuth. We want that
1035       // method to complete. Not setting next state here will make DoLoop exit
1036       // and in turn make Start/RestartWithAuth complete.
1037       break;
1038     case ERROR_CLASS_OK:
1039       next_state_ = STATE_CTRL_WRITE_QUIT;
1040       break;
1041     case ERROR_CLASS_INFO_NEEDED:
1042       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1043     case ERROR_CLASS_TRANSIENT_ERROR:
1044       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1045     case ERROR_CLASS_PERMANENT_ERROR:
1046       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1047     default:
1048       NOTREACHED();
1049       return Stop(ERR_UNEXPECTED);
1050   }
1051
1052   return OK;
1053 }
1054
1055 // SIZE command
1056 int FtpNetworkTransaction::DoCtrlWriteSIZE() {
1057   std::string command = "SIZE " + GetRequestPathForFtpCommand(false);
1058   next_state_ = STATE_CTRL_READ;
1059   return SendFtpCommand(command, command, COMMAND_SIZE);
1060 }
1061
1062 int FtpNetworkTransaction::ProcessResponseSIZE(
1063     const FtpCtrlResponse& response) {
1064   switch (GetErrorClass(response.status_code)) {
1065     case ERROR_CLASS_INITIATED:
1066       break;
1067     case ERROR_CLASS_OK:
1068       if (response.lines.size() != 1)
1069         return Stop(ERR_INVALID_RESPONSE);
1070       int64 size;
1071       if (!base::StringToInt64(response.lines[0], &size))
1072         return Stop(ERR_INVALID_RESPONSE);
1073       if (size < 0)
1074         return Stop(ERR_INVALID_RESPONSE);
1075
1076       // A successful response to SIZE does not mean the resource is a file.
1077       // Some FTP servers (for example, the qnx one) send a SIZE even for
1078       // directories.
1079       response_.expected_content_size = size;
1080       break;
1081     case ERROR_CLASS_INFO_NEEDED:
1082       break;
1083     case ERROR_CLASS_TRANSIENT_ERROR:
1084       break;
1085     case ERROR_CLASS_PERMANENT_ERROR:
1086       // It's possible that SIZE failed because the path is a directory.
1087       // TODO(xunjieli): Add a test for this case.
1088       if (resource_type_ == RESOURCE_TYPE_UNKNOWN &&
1089           response.status_code != 550) {
1090         return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1091       }
1092       break;
1093     default:
1094       NOTREACHED();
1095       return Stop(ERR_UNEXPECTED);
1096   }
1097
1098   // If the resource is known beforehand to be a file, RETR should be issued,
1099   // otherwise do CWD which will detect the resource type.
1100   if (resource_type_ == RESOURCE_TYPE_FILE)
1101     EstablishDataConnection(STATE_CTRL_WRITE_RETR);
1102   else
1103     next_state_ = STATE_CTRL_WRITE_CWD;
1104   return OK;
1105 }
1106
1107 // CWD command
1108 int FtpNetworkTransaction::DoCtrlWriteCWD() {
1109   std::string command = "CWD " + GetRequestPathForFtpCommand(true);
1110   next_state_ = STATE_CTRL_READ;
1111   return SendFtpCommand(command, command, COMMAND_CWD);
1112 }
1113
1114 int FtpNetworkTransaction::ProcessResponseCWD(const FtpCtrlResponse& response) {
1115   // CWD should be invoked only when the resource is not a file.
1116   DCHECK_NE(RESOURCE_TYPE_FILE, resource_type_);
1117
1118   switch (GetErrorClass(response.status_code)) {
1119     case ERROR_CLASS_INITIATED:
1120       return Stop(ERR_INVALID_RESPONSE);
1121     case ERROR_CLASS_OK:
1122       resource_type_ = RESOURCE_TYPE_DIRECTORY;
1123       EstablishDataConnection(STATE_CTRL_WRITE_LIST);
1124       break;
1125     case ERROR_CLASS_INFO_NEEDED:
1126       return Stop(ERR_INVALID_RESPONSE);
1127     case ERROR_CLASS_TRANSIENT_ERROR:
1128       // Some FTP servers send response 451 (not a valid CWD response according
1129       // to RFC 959) instead of 550.
1130       if (response.status_code == 451)
1131         return ProcessResponseCWDNotADirectory();
1132
1133       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1134     case ERROR_CLASS_PERMANENT_ERROR:
1135       if (response.status_code == 550)
1136         return ProcessResponseCWDNotADirectory();
1137
1138       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1139     default:
1140       NOTREACHED();
1141       return Stop(ERR_UNEXPECTED);
1142   }
1143
1144   return OK;
1145 }
1146
1147 int FtpNetworkTransaction::ProcessResponseCWDNotADirectory() {
1148   if (resource_type_ == RESOURCE_TYPE_DIRECTORY) {
1149     // We're assuming that the resource is a directory, but the server
1150     // says it's not true. The most probable interpretation is that it
1151     // doesn't exist (with FTP we can't be sure).
1152     return Stop(ERR_FILE_NOT_FOUND);
1153   }
1154
1155   // If it is not a directory, it is probably a file.
1156   resource_type_ = RESOURCE_TYPE_FILE;
1157
1158   EstablishDataConnection(STATE_CTRL_WRITE_RETR);
1159   return OK;
1160 }
1161
1162 // LIST command
1163 int FtpNetworkTransaction::DoCtrlWriteLIST() {
1164   // Use the -l option for mod_ftp configured in LISTIsNLST mode: the option
1165   // forces LIST output instead of NLST (which would be ambiguous for us
1166   // to parse).
1167   std::string command("LIST -l");
1168   if (system_type_ == SYSTEM_TYPE_VMS)
1169     command = "LIST *.*;0";
1170
1171   next_state_ = STATE_CTRL_READ;
1172   return SendFtpCommand(command, command, COMMAND_LIST);
1173 }
1174
1175 int FtpNetworkTransaction::ProcessResponseLIST(
1176     const FtpCtrlResponse& response) {
1177   // Resource type should be either filled in by DetectTypecode() or
1178   // detected with CWD. LIST is sent only when the resource is a directory.
1179   DCHECK_EQ(RESOURCE_TYPE_DIRECTORY, resource_type_);
1180
1181   switch (GetErrorClass(response.status_code)) {
1182     case ERROR_CLASS_INITIATED:
1183       // We want the client to start reading the response at this point.
1184       // It got here either through Start or RestartWithAuth. We want that
1185       // method to complete. Not setting next state here will make DoLoop exit
1186       // and in turn make Start/RestartWithAuth complete.
1187       response_.is_directory_listing = true;
1188       break;
1189     case ERROR_CLASS_OK:
1190       response_.is_directory_listing = true;
1191       next_state_ = STATE_CTRL_WRITE_QUIT;
1192       break;
1193     case ERROR_CLASS_INFO_NEEDED:
1194       return Stop(ERR_INVALID_RESPONSE);
1195     case ERROR_CLASS_TRANSIENT_ERROR:
1196       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1197     case ERROR_CLASS_PERMANENT_ERROR:
1198       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1199     default:
1200       NOTREACHED();
1201       return Stop(ERR_UNEXPECTED);
1202   }
1203   return OK;
1204 }
1205
1206 // QUIT command
1207 int FtpNetworkTransaction::DoCtrlWriteQUIT() {
1208   std::string command = "QUIT";
1209   next_state_ = STATE_CTRL_READ;
1210   return SendFtpCommand(command, command, COMMAND_QUIT);
1211 }
1212
1213 int FtpNetworkTransaction::ProcessResponseQUIT(
1214     const FtpCtrlResponse& response) {
1215   ctrl_socket_->Disconnect();
1216   return last_error_;
1217 }
1218
1219 // Data Connection
1220
1221 int FtpNetworkTransaction::DoDataConnect() {
1222   next_state_ = STATE_DATA_CONNECT_COMPLETE;
1223   IPEndPoint ip_endpoint;
1224   AddressList data_address;
1225   // Connect to the same host as the control socket to prevent PASV port
1226   // scanning attacks.
1227   int rv = ctrl_socket_->GetPeerAddress(&ip_endpoint);
1228   if (rv != OK)
1229     return Stop(rv);
1230   data_address = AddressList::CreateFromIPAddress(
1231       ip_endpoint.address(), data_connection_port_);
1232   data_socket_ = socket_factory_->CreateTransportClientSocket(
1233         data_address, net_log_.net_log(), net_log_.source());
1234   net_log_.AddEvent(
1235       NetLog::TYPE_FTP_DATA_CONNECTION,
1236       data_socket_->NetLog().source().ToEventParametersCallback());
1237   return data_socket_->Connect(io_callback_);
1238 }
1239
1240 int FtpNetworkTransaction::DoDataConnectComplete(int result) {
1241   if (result != OK && use_epsv_) {
1242     // It's possible we hit a broken server, sadly. They can break in different
1243     // ways. Some time out, some reset a connection. Fall back to PASV.
1244     // TODO(phajdan.jr): remember it for future transactions with this server.
1245     // TODO(phajdan.jr): write a test for this code path.
1246     use_epsv_ = false;
1247     next_state_ = STATE_CTRL_WRITE_PASV;
1248     return OK;
1249   }
1250
1251   // Only record the connection error after we've applied all our fallbacks.
1252   // We want to capture the final error, one we're not going to recover from.
1253   RecordDataConnectionError(result);
1254
1255   if (result != OK)
1256     return Stop(result);
1257
1258   next_state_ = state_after_data_connect_complete_;
1259   return OK;
1260 }
1261
1262 int FtpNetworkTransaction::DoDataRead() {
1263   DCHECK(read_data_buf_.get());
1264   DCHECK_GT(read_data_buf_len_, 0);
1265
1266   if (data_socket_ == NULL || !data_socket_->IsConnected()) {
1267     // If we don't destroy the data socket completely, some servers will wait
1268     // for us (http://crbug.com/21127). The half-closed TCP connection needs
1269     // to be closed on our side too.
1270     data_socket_.reset();
1271
1272     if (ctrl_socket_->IsConnected()) {
1273       // Wait for the server's response, we should get it before sending QUIT.
1274       next_state_ = STATE_CTRL_READ;
1275       return OK;
1276     }
1277
1278     // We are no longer connected to the server, so just finish the transaction.
1279     return Stop(OK);
1280   }
1281
1282   next_state_ = STATE_DATA_READ_COMPLETE;
1283   read_data_buf_->data()[0] = 0;
1284   return data_socket_->Read(
1285       read_data_buf_.get(), read_data_buf_len_, io_callback_);
1286 }
1287
1288 int FtpNetworkTransaction::DoDataReadComplete(int result) {
1289   return result;
1290 }
1291
1292 // We're using a histogram as a group of counters, with one bucket for each
1293 // enumeration value.  We're only interested in the values of the counters.
1294 // Ignore the shape, average, and standard deviation of the histograms because
1295 // they are meaningless.
1296 //
1297 // We use two histograms.  In the first histogram we tally whether the user has
1298 // seen an error of that type during the session.  In the second histogram we
1299 // tally the total number of times the users sees each errer.
1300 void FtpNetworkTransaction::RecordDataConnectionError(int result) {
1301   // Gather data for http://crbug.com/3073. See how many users have trouble
1302   // establishing FTP data connection in passive FTP mode.
1303   enum {
1304     // Data connection successful.
1305     NET_ERROR_OK = 0,
1306
1307     // Local firewall blocked the connection.
1308     NET_ERROR_ACCESS_DENIED = 1,
1309
1310     // Connection timed out.
1311     NET_ERROR_TIMED_OUT = 2,
1312
1313     // Connection has been estabilished, but then got broken (either reset
1314     // or aborted).
1315     NET_ERROR_CONNECTION_BROKEN = 3,
1316
1317     // Connection has been refused.
1318     NET_ERROR_CONNECTION_REFUSED = 4,
1319
1320     // No connection to the internet.
1321     NET_ERROR_INTERNET_DISCONNECTED = 5,
1322
1323     // Could not reach the destination address.
1324     NET_ERROR_ADDRESS_UNREACHABLE = 6,
1325
1326     // A programming error in our network stack.
1327     NET_ERROR_UNEXPECTED = 7,
1328
1329     // Other kind of error.
1330     NET_ERROR_OTHER = 20,
1331
1332     NUM_OF_NET_ERROR_TYPES
1333   } type;
1334   switch (result) {
1335     case OK:
1336       type = NET_ERROR_OK;
1337       break;
1338     case ERR_ACCESS_DENIED:
1339     case ERR_NETWORK_ACCESS_DENIED:
1340       type = NET_ERROR_ACCESS_DENIED;
1341       break;
1342     case ERR_TIMED_OUT:
1343       type = NET_ERROR_TIMED_OUT;
1344       break;
1345     case ERR_CONNECTION_ABORTED:
1346     case ERR_CONNECTION_RESET:
1347     case ERR_CONNECTION_CLOSED:
1348       type = NET_ERROR_CONNECTION_BROKEN;
1349       break;
1350     case ERR_CONNECTION_FAILED:
1351     case ERR_CONNECTION_REFUSED:
1352       type = NET_ERROR_CONNECTION_REFUSED;
1353       break;
1354     case ERR_INTERNET_DISCONNECTED:
1355       type = NET_ERROR_INTERNET_DISCONNECTED;
1356       break;
1357     case ERR_ADDRESS_INVALID:
1358     case ERR_ADDRESS_UNREACHABLE:
1359       type = NET_ERROR_ADDRESS_UNREACHABLE;
1360       break;
1361     case ERR_UNEXPECTED:
1362       type = NET_ERROR_UNEXPECTED;
1363       break;
1364     default:
1365       type = NET_ERROR_OTHER;
1366       break;
1367   };
1368   static bool had_error_type[NUM_OF_NET_ERROR_TYPES];
1369
1370   DCHECK(type >= 0 && type < NUM_OF_NET_ERROR_TYPES);
1371   if (!had_error_type[type]) {
1372     had_error_type[type] = true;
1373     UMA_HISTOGRAM_ENUMERATION("Net.FtpDataConnectionErrorHappened",
1374         type, NUM_OF_NET_ERROR_TYPES);
1375   }
1376   UMA_HISTOGRAM_ENUMERATION("Net.FtpDataConnectionErrorCount",
1377       type, NUM_OF_NET_ERROR_TYPES);
1378 }
1379
1380 }  // namespace net