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 (!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(ASCIIToUTF16("anonymous"),
 260                      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, &addresses_,
 654       base::Bind(&FtpNetworkTransaction::OnIOComplete, base::Unretained(this)),
 655       net_log_);
 656 }
 657
 658 int FtpNetworkTransaction::DoCtrlResolveHostComplete(int result) {
 659   if (result == OK)
 660     next_state_ = STATE_CTRL_CONNECT;
 661   return result;
 662 }
 663
 664 int FtpNetworkTransaction::DoCtrlConnect() {
 665   next_state_ = STATE_CTRL_CONNECT_COMPLETE;
 666   ctrl_socket_ = socket_factory_->CreateTransportClientSocket(
 667       addresses_, net_log_.net_log(), net_log_.source());
 668   net_log_.AddEvent(
 669       NetLog::TYPE_FTP_CONTROL_CONNECTION,
 670       ctrl_socket_->NetLog().source().ToEventParametersCallback());
 671   return ctrl_socket_->Connect(io_callback_);
 672 }
 673
 674 int FtpNetworkTransaction::DoCtrlConnectComplete(int result) {
 675   if (result == OK) {
 676     // Put the peer's IP address and port into the response.
 677     IPEndPoint ip_endpoint;
 678     result = ctrl_socket_->GetPeerAddress(&ip_endpoint);
 679     if (result == OK) {
 680       response_.socket_address = HostPortPair::FromIPEndPoint(ip_endpoint);
 681       next_state_ = STATE_CTRL_READ;
 682
 683       if (ip_endpoint.GetFamily() == ADDRESS_FAMILY_IPV4) {
 684         // Do not use EPSV for IPv4 connections. Some servers become confused
 685         // and we time out while waiting to connect. PASV is perfectly fine for
 686         // IPv4. Note that this blacklists IPv4 not to use EPSV instead of
 687         // whitelisting IPv6 to use it, to make the code more future-proof:
 688         // all future protocols should just use EPSV.
 689         use_epsv_ = false;
 690       }
 691     }
 692   }
 693   return result;
 694 }
 695
 696 int FtpNetworkTransaction::DoCtrlRead() {
 697   next_state_ = STATE_CTRL_READ_COMPLETE;
 698   return ctrl_socket_->Read(read_ctrl_buf_.get(), kCtrlBufLen, io_callback_);
 699 }
 700
 701 int FtpNetworkTransaction::DoCtrlReadComplete(int result) {
 702   if (result == 0) {
 703     // Some servers (for example Pure-FTPd) apparently close the control
 704     // connection when anonymous login is not permitted. For more details
 705     // see http://crbug.com/25023.
 706     if (command_sent_ == COMMAND_USER &&
 707         credentials_.username() == ASCIIToUTF16("anonymous")) {
 708       response_.needs_auth = true;
 709     }
 710     return Stop(ERR_EMPTY_RESPONSE);
 711   }
 712   if (result < 0)
 713     return Stop(result);
 714
 715   ctrl_response_buffer_->ConsumeData(read_ctrl_buf_->data(), result);
 716
 717   if (!ctrl_response_buffer_->ResponseAvailable()) {
 718     // Read more data from the control socket.
 719     next_state_ = STATE_CTRL_READ;
 720     return OK;
 721   }
 722
 723   return ProcessCtrlResponse();
 724 }
 725
 726 int FtpNetworkTransaction::DoCtrlWrite() {
 727   next_state_ = STATE_CTRL_WRITE_COMPLETE;
 728
 729   return ctrl_socket_->Write(
 730       write_buf_.get(), write_buf_->BytesRemaining(), io_callback_);
 731 }
 732
 733 int FtpNetworkTransaction::DoCtrlWriteComplete(int result) {
 734   if (result < 0)
 735     return result;
 736
 737   write_buf_->DidConsume(result);
 738   if (write_buf_->BytesRemaining() == 0) {
 739     // Clear the write buffer.
 740     write_buf_ = NULL;
 741     write_command_buf_ = NULL;
 742
 743     next_state_ = STATE_CTRL_READ;
 744   } else {
 745     next_state_ = STATE_CTRL_WRITE;
 746   }
 747   return OK;
 748 }
 749
 750 // FTP Commands and responses
 751
 752 // USER Command.
 753 int FtpNetworkTransaction::DoCtrlWriteUSER() {
 754   std::string command = "USER " + UTF16ToUTF8(credentials_.username());
 755
 756   if (!IsValidFTPCommandString(command))
 757     return Stop(ERR_MALFORMED_IDENTITY);
 758
 759   next_state_ = STATE_CTRL_READ;
 760   return SendFtpCommand(command, "USER ***", COMMAND_USER);
 761 }
 762
 763 int FtpNetworkTransaction::ProcessResponseUSER(
 764     const FtpCtrlResponse& response) {
 765   switch (GetErrorClass(response.status_code)) {
 766     case ERROR_CLASS_OK:
 767       next_state_ = STATE_CTRL_WRITE_SYST;
 768       break;
 769     case ERROR_CLASS_INFO_NEEDED:
 770       next_state_ = STATE_CTRL_WRITE_PASS;
 771       break;
 772     case ERROR_CLASS_TRANSIENT_ERROR:
 773     case ERROR_CLASS_PERMANENT_ERROR:
 774       response_.needs_auth = true;
 775       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 776     default:
 777       NOTREACHED();
 778       return Stop(ERR_UNEXPECTED);
 779   }
 780   return OK;
 781 }
 782
 783 // PASS command.
 784 int FtpNetworkTransaction::DoCtrlWritePASS() {
 785   std::string command = "PASS " + UTF16ToUTF8(credentials_.password());
 786
 787   if (!IsValidFTPCommandString(command))
 788     return Stop(ERR_MALFORMED_IDENTITY);
 789
 790   next_state_ = STATE_CTRL_READ;
 791   return SendFtpCommand(command, "PASS ***", COMMAND_PASS);
 792 }
 793
 794 int FtpNetworkTransaction::ProcessResponsePASS(
 795     const FtpCtrlResponse& response) {
 796   switch (GetErrorClass(response.status_code)) {
 797     case ERROR_CLASS_OK:
 798       next_state_ = STATE_CTRL_WRITE_SYST;
 799       break;
 800     case ERROR_CLASS_INFO_NEEDED:
 801       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 802     case ERROR_CLASS_TRANSIENT_ERROR:
 803     case ERROR_CLASS_PERMANENT_ERROR:
 804       response_.needs_auth = true;
 805       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 806     default:
 807       NOTREACHED();
 808       return Stop(ERR_UNEXPECTED);
 809   }
 810   return OK;
 811 }
 812
 813 // SYST command.
 814 int FtpNetworkTransaction::DoCtrlWriteSYST() {
 815   std::string command = "SYST";
 816   next_state_ = STATE_CTRL_READ;
 817   return SendFtpCommand(command, command, COMMAND_SYST);
 818 }
 819
 820 int FtpNetworkTransaction::ProcessResponseSYST(
 821     const FtpCtrlResponse& response) {
 822   switch (GetErrorClass(response.status_code)) {
 823     case ERROR_CLASS_INITIATED:
 824       return Stop(ERR_INVALID_RESPONSE);
 825     case ERROR_CLASS_OK: {
 826       // All important info should be on the first line.
 827       std::string line = response.lines[0];
 828       // The response should be ASCII, which allows us to do case-insensitive
 829       // comparisons easily. If it is not ASCII, we leave the system type
 830       // as unknown.
 831       if (IsStringASCII(line)) {
 832         line = StringToLowerASCII(line);
 833
 834         // Remove all whitespace, to correctly handle cases like fancy "V M S"
 835         // response instead of "VMS".
 836         RemoveChars(line, kWhitespaceASCII, &line);
 837
 838         // The "magic" strings we test for below have been gathered by an
 839         // empirical study. VMS needs to come first because some VMS systems
 840         // also respond with "UNIX emulation", which is not perfect. It is much
 841         // more reliable to talk to these servers in their native language.
 842         if (line.find("vms") != std::string::npos) {
 843           system_type_ = SYSTEM_TYPE_VMS;
 844         } else if (line.find("l8") != std::string::npos ||
 845                    line.find("unix") != std::string::npos ||
 846                    line.find("bsd") != std::string::npos) {
 847           system_type_ = SYSTEM_TYPE_UNIX;
 848         } else if (line.find("win32") != std::string::npos ||
 849                    line.find("windows") != std::string::npos) {
 850           system_type_ = SYSTEM_TYPE_WINDOWS;
 851         } else if (line.find("os/2") != std::string::npos) {
 852           system_type_ = SYSTEM_TYPE_OS2;
 853         }
 854       }
 855       next_state_ = STATE_CTRL_WRITE_PWD;
 856       break;
 857     }
 858     case ERROR_CLASS_INFO_NEEDED:
 859       return Stop(ERR_INVALID_RESPONSE);
 860     case ERROR_CLASS_TRANSIENT_ERROR:
 861       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 862     case ERROR_CLASS_PERMANENT_ERROR:
 863       // Server does not recognize the SYST command so proceed.
 864       next_state_ = STATE_CTRL_WRITE_PWD;
 865       break;
 866     default:
 867       NOTREACHED();
 868       return Stop(ERR_UNEXPECTED);
 869   }
 870   return OK;
 871 }
 872
 873 // PWD command.
 874 int FtpNetworkTransaction::DoCtrlWritePWD() {
 875   std::string command = "PWD";
 876   next_state_ = STATE_CTRL_READ;
 877   return SendFtpCommand(command, command, COMMAND_PWD);
 878 }
 879
 880 int FtpNetworkTransaction::ProcessResponsePWD(const FtpCtrlResponse& response) {
 881   switch (GetErrorClass(response.status_code)) {
 882     case ERROR_CLASS_INITIATED:
 883       return Stop(ERR_INVALID_RESPONSE);
 884     case ERROR_CLASS_OK: {
 885       // The info we look for should be on the first line.
 886       std::string line = response.lines[0];
 887       if (line.empty())
 888         return Stop(ERR_INVALID_RESPONSE);
 889       std::string::size_type quote_pos = line.find('"');
 890       if (quote_pos != std::string::npos) {
 891         line = line.substr(quote_pos + 1);
 892         quote_pos = line.find('"');
 893         if (quote_pos == std::string::npos)
 894           return Stop(ERR_INVALID_RESPONSE);
 895         line = line.substr(0, quote_pos);
 896       }
 897       if (system_type_ == SYSTEM_TYPE_VMS)
 898         line = FtpUtil::VMSPathToUnix(line);
 899       if (line.length() && line[line.length() - 1] == '/')
 900         line.erase(line.length() - 1);
 901       current_remote_directory_ = line;
 902       next_state_ = STATE_CTRL_WRITE_TYPE;
 903       break;
 904     }
 905     case ERROR_CLASS_INFO_NEEDED:
 906       return Stop(ERR_INVALID_RESPONSE);
 907     case ERROR_CLASS_TRANSIENT_ERROR:
 908       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 909     case ERROR_CLASS_PERMANENT_ERROR:
 910       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 911     default:
 912       NOTREACHED();
 913       return Stop(ERR_UNEXPECTED);
 914   }
 915   return OK;
 916 }
 917
 918 // TYPE command.
 919 int FtpNetworkTransaction::DoCtrlWriteTYPE() {
 920   std::string command = "TYPE ";
 921   if (data_type_ == DATA_TYPE_ASCII) {
 922     command += "A";
 923   } else if (data_type_ == DATA_TYPE_IMAGE) {
 924     command += "I";
 925   } else {
 926     NOTREACHED();
 927     return Stop(ERR_UNEXPECTED);
 928   }
 929   next_state_ = STATE_CTRL_READ;
 930   return SendFtpCommand(command, command, COMMAND_TYPE);
 931 }
 932
 933 int FtpNetworkTransaction::ProcessResponseTYPE(
 934     const FtpCtrlResponse& response) {
 935   switch (GetErrorClass(response.status_code)) {
 936     case ERROR_CLASS_INITIATED:
 937       return Stop(ERR_INVALID_RESPONSE);
 938     case ERROR_CLASS_OK:
 939       next_state_ = use_epsv_ ? STATE_CTRL_WRITE_EPSV : STATE_CTRL_WRITE_PASV;
 940       break;
 941     case ERROR_CLASS_INFO_NEEDED:
 942       return Stop(ERR_INVALID_RESPONSE);
 943     case ERROR_CLASS_TRANSIENT_ERROR:
 944       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 945     case ERROR_CLASS_PERMANENT_ERROR:
 946       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
 947     default:
 948       NOTREACHED();
 949       return Stop(ERR_UNEXPECTED);
 950   }
 951   return OK;
 952 }
 953
 954 // EPSV command
 955 int FtpNetworkTransaction::DoCtrlWriteEPSV() {
 956   const std::string command = "EPSV";
 957   next_state_ = STATE_CTRL_READ;
 958   return SendFtpCommand(command, command, COMMAND_EPSV);
 959 }
 960
 961 int FtpNetworkTransaction::ProcessResponseEPSV(
 962     const FtpCtrlResponse& response) {
 963   switch (GetErrorClass(response.status_code)) {
 964     case ERROR_CLASS_INITIATED:
 965       return Stop(ERR_INVALID_RESPONSE);
 966     case ERROR_CLASS_OK:
 967       if (!ExtractPortFromEPSVResponse( response, &data_connection_port_))
 968         return Stop(ERR_INVALID_RESPONSE);
 969       if (data_connection_port_ < 1024 ||
 970           !IsPortAllowedByFtp(data_connection_port_))
 971         return Stop(ERR_UNSAFE_PORT);
 972       next_state_ = STATE_DATA_CONNECT;
 973       break;
 974     case ERROR_CLASS_INFO_NEEDED:
 975       return Stop(ERR_INVALID_RESPONSE);
 976     case ERROR_CLASS_TRANSIENT_ERROR:
 977     case ERROR_CLASS_PERMANENT_ERROR:
 978       use_epsv_ = false;
 979       next_state_ = STATE_CTRL_WRITE_PASV;
 980       return OK;
 981     default:
 982       NOTREACHED();
 983       return Stop(ERR_UNEXPECTED);
 984   }
 985   return OK;
 986 }
 987
 988 // PASV command
 989 int FtpNetworkTransaction::DoCtrlWritePASV() {
 990   std::string command = "PASV";
 991   next_state_ = STATE_CTRL_READ;
 992   return SendFtpCommand(command, command, COMMAND_PASV);
 993 }
 994
 995 int FtpNetworkTransaction::ProcessResponsePASV(
 996     const FtpCtrlResponse& response) {
 997   switch (GetErrorClass(response.status_code)) {
 998     case ERROR_CLASS_INITIATED:
 999       return Stop(ERR_INVALID_RESPONSE);
1000     case ERROR_CLASS_OK:
1001       if (!ExtractPortFromPASVResponse(response, &data_connection_port_))
1002         return Stop(ERR_INVALID_RESPONSE);
1003       if (data_connection_port_ < 1024 ||
1004           !IsPortAllowedByFtp(data_connection_port_))
1005         return Stop(ERR_UNSAFE_PORT);
1006       next_state_ = STATE_DATA_CONNECT;
1007       break;
1008     case ERROR_CLASS_INFO_NEEDED:
1009       return Stop(ERR_INVALID_RESPONSE);
1010     case ERROR_CLASS_TRANSIENT_ERROR:
1011       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1012     case ERROR_CLASS_PERMANENT_ERROR:
1013       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1014     default:
1015       NOTREACHED();
1016       return Stop(ERR_UNEXPECTED);
1017   }
1018   return OK;
1019 }
1020
1021 // RETR command
1022 int FtpNetworkTransaction::DoCtrlWriteRETR() {
1023   std::string command = "RETR " + GetRequestPathForFtpCommand(false);
1024   next_state_ = STATE_CTRL_READ;
1025   return SendFtpCommand(command, command, COMMAND_RETR);
1026 }
1027
1028 int FtpNetworkTransaction::ProcessResponseRETR(
1029     const FtpCtrlResponse& response) {
1030   switch (GetErrorClass(response.status_code)) {
1031     case ERROR_CLASS_INITIATED:
1032       // We want the client to start reading the response at this point.
1033       // It got here either through Start or RestartWithAuth. We want that
1034       // method to complete. Not setting next state here will make DoLoop exit
1035       // and in turn make Start/RestartWithAuth complete.
1036       resource_type_ = RESOURCE_TYPE_FILE;
1037       break;
1038     case ERROR_CLASS_OK:
1039       resource_type_ = RESOURCE_TYPE_FILE;
1040       next_state_ = STATE_CTRL_WRITE_QUIT;
1041       break;
1042     case ERROR_CLASS_INFO_NEEDED:
1043       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1044     case ERROR_CLASS_TRANSIENT_ERROR:
1045       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1046     case ERROR_CLASS_PERMANENT_ERROR:
1047       // Code 550 means "Failed to open file". Other codes are unrelated,
1048       // like "Not logged in" etc.
1049       if (response.status_code != 550 || resource_type_ == RESOURCE_TYPE_FILE)
1050         return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1051
1052       // It's possible that RETR failed because the path is a directory.
1053       resource_type_ = RESOURCE_TYPE_DIRECTORY;
1054
1055       // We're going to try CWD next, but first send a PASV one more time,
1056       // because some FTP servers, including FileZilla, require that.
1057       // See http://crbug.com/25316.
1058       next_state_ = use_epsv_ ? STATE_CTRL_WRITE_EPSV : STATE_CTRL_WRITE_PASV;
1059       break;
1060     default:
1061       NOTREACHED();
1062       return Stop(ERR_UNEXPECTED);
1063   }
1064
1065   // We should be sure about our resource type now. Otherwise we risk
1066   // an infinite loop (RETR can later send CWD, and CWD can later send RETR).
1067   DCHECK_NE(RESOURCE_TYPE_UNKNOWN, resource_type_);
1068
1069   return OK;
1070 }
1071
1072 // SIZE command
1073 int FtpNetworkTransaction::DoCtrlWriteSIZE() {
1074   std::string command = "SIZE " + GetRequestPathForFtpCommand(false);
1075   next_state_ = STATE_CTRL_READ;
1076   return SendFtpCommand(command, command, COMMAND_SIZE);
1077 }
1078
1079 int FtpNetworkTransaction::ProcessResponseSIZE(
1080     const FtpCtrlResponse& response) {
1081   State state_after_size;
1082   if (resource_type_ == RESOURCE_TYPE_FILE)
1083     state_after_size = STATE_CTRL_WRITE_RETR;
1084   else
1085     state_after_size = STATE_CTRL_WRITE_CWD;
1086
1087   switch (GetErrorClass(response.status_code)) {
1088     case ERROR_CLASS_INITIATED:
1089       next_state_ = state_after_size;
1090       break;
1091     case ERROR_CLASS_OK:
1092       if (response.lines.size() != 1)
1093         return Stop(ERR_INVALID_RESPONSE);
1094       int64 size;
1095       if (!base::StringToInt64(response.lines[0], &size))
1096         return Stop(ERR_INVALID_RESPONSE);
1097       if (size < 0)
1098         return Stop(ERR_INVALID_RESPONSE);
1099
1100       // A successful response to SIZE does not mean the resource is a file.
1101       // Some FTP servers (for example, the qnx one) send a SIZE even for
1102       // directories.
1103       response_.expected_content_size = size;
1104
1105       next_state_ = state_after_size;
1106       break;
1107     case ERROR_CLASS_INFO_NEEDED:
1108       next_state_ = state_after_size;
1109       break;
1110     case ERROR_CLASS_TRANSIENT_ERROR:
1111       ResetDataConnectionAfterError(state_after_size);
1112       break;
1113     case ERROR_CLASS_PERMANENT_ERROR:
1114       // It's possible that SIZE failed because the path is a directory.
1115       if (resource_type_ == RESOURCE_TYPE_UNKNOWN &&
1116           response.status_code != 550) {
1117         return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1118       }
1119
1120       ResetDataConnectionAfterError(state_after_size);
1121       break;
1122     default:
1123       NOTREACHED();
1124       return Stop(ERR_UNEXPECTED);
1125   }
1126
1127   return OK;
1128 }
1129
1130 // CWD command
1131 int FtpNetworkTransaction::DoCtrlWriteCWD() {
1132   std::string command = "CWD " + GetRequestPathForFtpCommand(true);
1133   next_state_ = STATE_CTRL_READ;
1134   return SendFtpCommand(command, command, COMMAND_CWD);
1135 }
1136
1137 int FtpNetworkTransaction::ProcessResponseCWD(const FtpCtrlResponse& response) {
1138   // We should never issue CWD if we know the target resource is a file.
1139   DCHECK_NE(RESOURCE_TYPE_FILE, resource_type_);
1140
1141   switch (GetErrorClass(response.status_code)) {
1142     case ERROR_CLASS_INITIATED:
1143       return Stop(ERR_INVALID_RESPONSE);
1144     case ERROR_CLASS_OK:
1145       next_state_ = STATE_CTRL_WRITE_LIST;
1146       break;
1147     case ERROR_CLASS_INFO_NEEDED:
1148       return Stop(ERR_INVALID_RESPONSE);
1149     case ERROR_CLASS_TRANSIENT_ERROR:
1150       // Some FTP servers send response 451 (not a valid CWD response according
1151       // to RFC 959) instead of 550.
1152       if (response.status_code == 451)
1153         return ProcessResponseCWDNotADirectory();
1154
1155       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1156     case ERROR_CLASS_PERMANENT_ERROR:
1157       if (response.status_code == 550)
1158         return ProcessResponseCWDNotADirectory();
1159
1160       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1161     default:
1162       NOTREACHED();
1163       return Stop(ERR_UNEXPECTED);
1164   }
1165
1166   return OK;
1167 }
1168
1169 int FtpNetworkTransaction::ProcessResponseCWDNotADirectory() {
1170   if (resource_type_ == RESOURCE_TYPE_DIRECTORY) {
1171     // We're assuming that the resource is a directory, but the server
1172     // says it's not true. The most probable interpretation is that it
1173     // doesn't exist (with FTP we can't be sure).
1174     return Stop(ERR_FILE_NOT_FOUND);
1175   }
1176
1177   // We are here because SIZE failed and we are not sure what the resource
1178   // type is. It could still be file, and SIZE could fail because of
1179   // an access error (http://crbug.com/56734). Try RETR just to be sure.
1180   resource_type_ = RESOURCE_TYPE_FILE;
1181
1182   ResetDataConnectionAfterError(STATE_CTRL_WRITE_RETR);
1183   return OK;
1184 }
1185
1186 // LIST command
1187 int FtpNetworkTransaction::DoCtrlWriteLIST() {
1188   // Use the -l option for mod_ftp configured in LISTIsNLST mode: the option
1189   // forces LIST output instead of NLST (which would be ambiguous for us
1190   // to parse).
1191   std::string command("LIST -l");
1192   if (system_type_ == SYSTEM_TYPE_VMS)
1193     command = "LIST *.*;0";
1194
1195   next_state_ = STATE_CTRL_READ;
1196   return SendFtpCommand(command, command, COMMAND_LIST);
1197 }
1198
1199 int FtpNetworkTransaction::ProcessResponseLIST(
1200     const FtpCtrlResponse& response) {
1201   switch (GetErrorClass(response.status_code)) {
1202     case ERROR_CLASS_INITIATED:
1203       // We want the client to start reading the response at this point.
1204       // It got here either through Start or RestartWithAuth. We want that
1205       // method to complete. Not setting next state here will make DoLoop exit
1206       // and in turn make Start/RestartWithAuth complete.
1207       response_.is_directory_listing = true;
1208       break;
1209     case ERROR_CLASS_OK:
1210       response_.is_directory_listing = true;
1211       next_state_ = STATE_CTRL_WRITE_QUIT;
1212       break;
1213     case ERROR_CLASS_INFO_NEEDED:
1214       return Stop(ERR_INVALID_RESPONSE);
1215     case ERROR_CLASS_TRANSIENT_ERROR:
1216       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1217     case ERROR_CLASS_PERMANENT_ERROR:
1218       return Stop(GetNetErrorCodeForFtpResponseCode(response.status_code));
1219     default:
1220       NOTREACHED();
1221       return Stop(ERR_UNEXPECTED);
1222   }
1223   return OK;
1224 }
1225
1226 // QUIT command
1227 int FtpNetworkTransaction::DoCtrlWriteQUIT() {
1228   std::string command = "QUIT";
1229   next_state_ = STATE_CTRL_READ;
1230   return SendFtpCommand(command, command, COMMAND_QUIT);
1231 }
1232
1233 int FtpNetworkTransaction::ProcessResponseQUIT(
1234     const FtpCtrlResponse& response) {
1235   ctrl_socket_->Disconnect();
1236   return last_error_;
1237 }
1238
1239 // Data Connection
1240
1241 int FtpNetworkTransaction::DoDataConnect() {
1242   next_state_ = STATE_DATA_CONNECT_COMPLETE;
1243   IPEndPoint ip_endpoint;
1244   AddressList data_address;
1245   // Connect to the same host as the control socket to prevent PASV port
1246   // scanning attacks.
1247   int rv = ctrl_socket_->GetPeerAddress(&ip_endpoint);
1248   if (rv != OK)
1249     return Stop(rv);
1250   data_address = AddressList::CreateFromIPAddress(
1251       ip_endpoint.address(), data_connection_port_);
1252   data_socket_ = socket_factory_->CreateTransportClientSocket(
1253         data_address, net_log_.net_log(), net_log_.source());
1254   net_log_.AddEvent(
1255       NetLog::TYPE_FTP_DATA_CONNECTION,
1256       data_socket_->NetLog().source().ToEventParametersCallback());
1257   return data_socket_->Connect(io_callback_);
1258 }
1259
1260 int FtpNetworkTransaction::DoDataConnectComplete(int result) {
1261   if (result != OK && use_epsv_) {
1262     // It's possible we hit a broken server, sadly. They can break in different
1263     // ways. Some time out, some reset a connection. Fall back to PASV.
1264     // TODO(phajdan.jr): remember it for future transactions with this server.
1265     // TODO(phajdan.jr): write a test for this code path.
1266     use_epsv_ = false;
1267     next_state_ = STATE_CTRL_WRITE_PASV;
1268     return OK;
1269   }
1270
1271   // Only record the connection error after we've applied all our fallbacks.
1272   // We want to capture the final error, one we're not going to recover from.
1273   RecordDataConnectionError(result);
1274
1275   if (result != OK)
1276     return Stop(result);
1277
1278   next_state_ = state_after_data_connect_complete_;
1279   return OK;
1280 }
1281
1282 int FtpNetworkTransaction::DoDataRead() {
1283   DCHECK(read_data_buf_.get());
1284   DCHECK_GT(read_data_buf_len_, 0);
1285
1286   if (data_socket_ == NULL || !data_socket_->IsConnected()) {
1287     // If we don't destroy the data socket completely, some servers will wait
1288     // for us (http://crbug.com/21127). The half-closed TCP connection needs
1289     // to be closed on our side too.
1290     data_socket_.reset();
1291
1292     if (ctrl_socket_->IsConnected()) {
1293       // Wait for the server's response, we should get it before sending QUIT.
1294       next_state_ = STATE_CTRL_READ;
1295       return OK;
1296     }
1297
1298     // We are no longer connected to the server, so just finish the transaction.
1299     return Stop(OK);
1300   }
1301
1302   next_state_ = STATE_DATA_READ_COMPLETE;
1303   read_data_buf_->data()[0] = 0;
1304   return data_socket_->Read(
1305       read_data_buf_.get(), read_data_buf_len_, io_callback_);
1306 }
1307
1308 int FtpNetworkTransaction::DoDataReadComplete(int result) {
1309   return result;
1310 }
1311
1312 // We're using a histogram as a group of counters, with one bucket for each
1313 // enumeration value.  We're only interested in the values of the counters.
1314 // Ignore the shape, average, and standard deviation of the histograms because
1315 // they are meaningless.
1316 //
1317 // We use two histograms.  In the first histogram we tally whether the user has
1318 // seen an error of that type during the session.  In the second histogram we
1319 // tally the total number of times the users sees each errer.
1320 void FtpNetworkTransaction::RecordDataConnectionError(int result) {
1321   // Gather data for http://crbug.com/3073. See how many users have trouble
1322   // establishing FTP data connection in passive FTP mode.
1323   enum {
1324     // Data connection successful.
1325     NET_ERROR_OK = 0,
1326
1327     // Local firewall blocked the connection.
1328     NET_ERROR_ACCESS_DENIED = 1,
1329
1330     // Connection timed out.
1331     NET_ERROR_TIMED_OUT = 2,
1332
1333     // Connection has been estabilished, but then got broken (either reset
1334     // or aborted).
1335     NET_ERROR_CONNECTION_BROKEN = 3,
1336
1337     // Connection has been refused.
1338     NET_ERROR_CONNECTION_REFUSED = 4,
1339
1340     // No connection to the internet.
1341     NET_ERROR_INTERNET_DISCONNECTED = 5,
1342
1343     // Could not reach the destination address.
1344     NET_ERROR_ADDRESS_UNREACHABLE = 6,
1345
1346     // A programming error in our network stack.
1347     NET_ERROR_UNEXPECTED = 7,
1348
1349     // Other kind of error.
1350     NET_ERROR_OTHER = 20,
1351
1352     NUM_OF_NET_ERROR_TYPES
1353   } type;
1354   switch (result) {
1355     case OK:
1356       type = NET_ERROR_OK;
1357       break;
1358     case ERR_ACCESS_DENIED:
1359     case ERR_NETWORK_ACCESS_DENIED:
1360       type = NET_ERROR_ACCESS_DENIED;
1361       break;
1362     case ERR_TIMED_OUT:
1363       type = NET_ERROR_TIMED_OUT;
1364       break;
1365     case ERR_CONNECTION_ABORTED:
1366     case ERR_CONNECTION_RESET:
1367     case ERR_CONNECTION_CLOSED:
1368       type = NET_ERROR_CONNECTION_BROKEN;
1369       break;
1370     case ERR_CONNECTION_FAILED:
1371     case ERR_CONNECTION_REFUSED:
1372       type = NET_ERROR_CONNECTION_REFUSED;
1373       break;
1374     case ERR_INTERNET_DISCONNECTED:
1375       type = NET_ERROR_INTERNET_DISCONNECTED;
1376       break;
1377     case ERR_ADDRESS_INVALID:
1378     case ERR_ADDRESS_UNREACHABLE:
1379       type = NET_ERROR_ADDRESS_UNREACHABLE;
1380       break;
1381     case ERR_UNEXPECTED:
1382       type = NET_ERROR_UNEXPECTED;
1383       break;
1384     default:
1385       type = NET_ERROR_OTHER;
1386       break;
1387   };
1388   static bool had_error_type[NUM_OF_NET_ERROR_TYPES];
1389
1390   DCHECK(type >= 0 && type < NUM_OF_NET_ERROR_TYPES);
1391   if (!had_error_type[type]) {
1392     had_error_type[type] = true;
1393     UMA_HISTOGRAM_ENUMERATION("Net.FtpDataConnectionErrorHappened",
1394         type, NUM_OF_NET_ERROR_TYPES);
1395   }
1396   UMA_HISTOGRAM_ENUMERATION("Net.FtpDataConnectionErrorCount",
1397       type, NUM_OF_NET_ERROR_TYPES);
1398 }
1399
1400 }  // namespace net