net/websockets/websocket_basic_handshake_stream.cc

   1 // Copyright 2013 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/websockets/websocket_basic_handshake_stream.h"
   6
   7 #include <algorithm>
   8 #include <iterator>
   9 #include <set>
  10 #include <string>
  11 #include <vector>
  12
  13 #include "base/base64.h"
  14 #include "base/basictypes.h"
  15 #include "base/bind.h"
  16 #include "base/compiler_specific.h"
  17 #include "base/containers/hash_tables.h"
  18 #include "base/logging.h"
  19 #include "base/metrics/histogram.h"
  20 #include "base/metrics/sparse_histogram.h"
  21 #include "base/stl_util.h"
  22 #include "base/strings/string_number_conversions.h"
  23 #include "base/strings/string_piece.h"
  24 #include "base/strings/string_util.h"
  25 #include "base/strings/stringprintf.h"
  26 #include "base/time/time.h"
  27 #include "crypto/random.h"
  28 #include "net/base/io_buffer.h"
  29 #include "net/http/http_request_headers.h"
  30 #include "net/http/http_request_info.h"
  31 #include "net/http/http_response_body_drainer.h"
  32 #include "net/http/http_response_headers.h"
  33 #include "net/http/http_status_code.h"
  34 #include "net/http/http_stream_parser.h"
  35 #include "net/socket/client_socket_handle.h"
  36 #include "net/socket/websocket_transport_client_socket_pool.h"
  37 #include "net/websockets/websocket_basic_stream.h"
  38 #include "net/websockets/websocket_deflate_predictor.h"
  39 #include "net/websockets/websocket_deflate_predictor_impl.h"
  40 #include "net/websockets/websocket_deflate_stream.h"
  41 #include "net/websockets/websocket_deflater.h"
  42 #include "net/websockets/websocket_extension_parser.h"
  43 #include "net/websockets/websocket_handshake_challenge.h"
  44 #include "net/websockets/websocket_handshake_constants.h"
  45 #include "net/websockets/websocket_handshake_request_info.h"
  46 #include "net/websockets/websocket_handshake_response_info.h"
  47 #include "net/websockets/websocket_stream.h"
  48
  49 namespace net {
  50
  51 namespace {
  52
  53 const char kConnectionErrorStatusLine[] = "HTTP/1.1 503 Connection Error";
  54
  55 }  // namespace
  56
  57 // TODO(ricea): If more extensions are added, replace this with a more general
  58 // mechanism.
  59 struct WebSocketExtensionParams {
  60   WebSocketExtensionParams()
  61       : deflate_enabled(false),
  62         client_window_bits(15),
  63         deflate_mode(WebSocketDeflater::TAKE_OVER_CONTEXT) {}
  64
  65   bool deflate_enabled;
  66   int client_window_bits;
  67   WebSocketDeflater::ContextTakeOverMode deflate_mode;
  68 };
  69
  70 namespace {
  71
  72 enum GetHeaderResult {
  73   GET_HEADER_OK,
  74   GET_HEADER_MISSING,
  75   GET_HEADER_MULTIPLE,
  76 };
  77
  78 std::string MissingHeaderMessage(const std::string& header_name) {
  79   return std::string("'") + header_name + "' header is missing";
  80 }
  81
  82 std::string MultipleHeaderValuesMessage(const std::string& header_name) {
  83   return
  84       std::string("'") +
  85       header_name +
  86       "' header must not appear more than once in a response";
  87 }
  88
  89 std::string GenerateHandshakeChallenge() {
  90   std::string raw_challenge(websockets::kRawChallengeLength, '\0');
  91   crypto::RandBytes(string_as_array(&raw_challenge), raw_challenge.length());
  92   std::string encoded_challenge;
  93   base::Base64Encode(raw_challenge, &encoded_challenge);
  94   return encoded_challenge;
  95 }
  96
  97 void AddVectorHeaderIfNonEmpty(const char* name,
  98                                const std::vector<std::string>& value,
  99                                HttpRequestHeaders* headers) {
 100   if (value.empty())
 101     return;
 102   headers->SetHeader(name, JoinString(value, ", "));
 103 }
 104
 105 GetHeaderResult GetSingleHeaderValue(const HttpResponseHeaders* headers,
 106                                      const base::StringPiece& name,
 107                                      std::string* value) {
 108   void* state = nullptr;
 109   size_t num_values = 0;
 110   std::string temp_value;
 111   while (headers->EnumerateHeader(&state, name, &temp_value)) {
 112     if (++num_values > 1)
 113       return GET_HEADER_MULTIPLE;
 114     *value = temp_value;
 115   }
 116   return num_values > 0 ? GET_HEADER_OK : GET_HEADER_MISSING;
 117 }
 118
 119 bool ValidateHeaderHasSingleValue(GetHeaderResult result,
 120                                   const std::string& header_name,
 121                                   std::string* failure_message) {
 122   if (result == GET_HEADER_MISSING) {
 123     *failure_message = MissingHeaderMessage(header_name);
 124     return false;
 125   }
 126   if (result == GET_HEADER_MULTIPLE) {
 127     *failure_message = MultipleHeaderValuesMessage(header_name);
 128     return false;
 129   }
 130   DCHECK_EQ(result, GET_HEADER_OK);
 131   return true;
 132 }
 133
 134 bool ValidateUpgrade(const HttpResponseHeaders* headers,
 135                      std::string* failure_message) {
 136   std::string value;
 137   GetHeaderResult result =
 138       GetSingleHeaderValue(headers, websockets::kUpgrade, &value);
 139   if (!ValidateHeaderHasSingleValue(result,
 140                                     websockets::kUpgrade,
 141                                     failure_message)) {
 142     return false;
 143   }
 144
 145   if (!LowerCaseEqualsASCII(value, websockets::kWebSocketLowercase)) {
 146     *failure_message =
 147         "'Upgrade' header value is not 'WebSocket': " + value;
 148     return false;
 149   }
 150   return true;
 151 }
 152
 153 bool ValidateSecWebSocketAccept(const HttpResponseHeaders* headers,
 154                                 const std::string& expected,
 155                                 std::string* failure_message) {
 156   std::string actual;
 157   GetHeaderResult result =
 158       GetSingleHeaderValue(headers, websockets::kSecWebSocketAccept, &actual);
 159   if (!ValidateHeaderHasSingleValue(result,
 160                                     websockets::kSecWebSocketAccept,
 161                                     failure_message)) {
 162     return false;
 163   }
 164
 165   if (expected != actual) {
 166     *failure_message = "Incorrect 'Sec-WebSocket-Accept' header value";
 167     return false;
 168   }
 169   return true;
 170 }
 171
 172 bool ValidateConnection(const HttpResponseHeaders* headers,
 173                         std::string* failure_message) {
 174   // Connection header is permitted to contain other tokens.
 175   if (!headers->HasHeader(HttpRequestHeaders::kConnection)) {
 176     *failure_message = MissingHeaderMessage(HttpRequestHeaders::kConnection);
 177     return false;
 178   }
 179   if (!headers->HasHeaderValue(HttpRequestHeaders::kConnection,
 180                                websockets::kUpgrade)) {
 181     *failure_message = "'Connection' header value must contain 'Upgrade'";
 182     return false;
 183   }
 184   return true;
 185 }
 186
 187 bool ValidateSubProtocol(
 188     const HttpResponseHeaders* headers,
 189     const std::vector<std::string>& requested_sub_protocols,
 190     std::string* sub_protocol,
 191     std::string* failure_message) {
 192   void* state = nullptr;
 193   std::string value;
 194   base::hash_set<std::string> requested_set(requested_sub_protocols.begin(),
 195                                             requested_sub_protocols.end());
 196   int count = 0;
 197   bool has_multiple_protocols = false;
 198   bool has_invalid_protocol = false;
 199
 200   while (!has_invalid_protocol || !has_multiple_protocols) {
 201     std::string temp_value;
 202     if (!headers->EnumerateHeader(
 203             &state, websockets::kSecWebSocketProtocol, &temp_value))
 204       break;
 205     value = temp_value;
 206     if (requested_set.count(value) == 0)
 207       has_invalid_protocol = true;
 208     if (++count > 1)
 209       has_multiple_protocols = true;
 210   }
 211
 212   if (has_multiple_protocols) {
 213     *failure_message =
 214         MultipleHeaderValuesMessage(websockets::kSecWebSocketProtocol);
 215     return false;
 216   } else if (count > 0 && requested_sub_protocols.size() == 0) {
 217     *failure_message =
 218         std::string("Response must not include 'Sec-WebSocket-Protocol' "
 219                     "header if not present in request: ")
 220         + value;
 221     return false;
 222   } else if (has_invalid_protocol) {
 223     *failure_message =
 224         "'Sec-WebSocket-Protocol' header value '" +
 225         value +
 226         "' in response does not match any of sent values";
 227     return false;
 228   } else if (requested_sub_protocols.size() > 0 && count == 0) {
 229     *failure_message =
 230         "Sent non-empty 'Sec-WebSocket-Protocol' header "
 231         "but no response was received";
 232     return false;
 233   }
 234   *sub_protocol = value;
 235   return true;
 236 }
 237
 238 bool DeflateError(std::string* message, const base::StringPiece& piece) {
 239   *message = "Error in permessage-deflate: ";
 240   piece.AppendToString(message);
 241   return false;
 242 }
 243
 244 bool ValidatePerMessageDeflateExtension(const WebSocketExtension& extension,
 245                                         std::string* failure_message,
 246                                         WebSocketExtensionParams* params) {
 247   static const char kClientPrefix[] = "client_";
 248   static const char kServerPrefix[] = "server_";
 249   static const char kNoContextTakeover[] = "no_context_takeover";
 250   static const char kMaxWindowBits[] = "max_window_bits";
 251   const size_t kPrefixLen = arraysize(kClientPrefix) - 1;
 252   static_assert(kPrefixLen == arraysize(kServerPrefix) - 1,
 253                 "the strings server and client must be the same length");
 254   typedef std::vector<WebSocketExtension::Parameter> ParameterVector;
 255
 256   DCHECK_EQ("permessage-deflate", extension.name());
 257   const ParameterVector& parameters = extension.parameters();
 258   std::set<std::string> seen_names;
 259   for (ParameterVector::const_iterator it = parameters.begin();
 260        it != parameters.end(); ++it) {
 261     const std::string& name = it->name();
 262     if (seen_names.count(name) != 0) {
 263       return DeflateError(
 264           failure_message,
 265           "Received duplicate permessage-deflate extension parameter " + name);
 266     }
 267     seen_names.insert(name);
 268     const std::string client_or_server(name, 0, kPrefixLen);
 269     const bool is_client = (client_or_server == kClientPrefix);
 270     if (!is_client && client_or_server != kServerPrefix) {
 271       return DeflateError(
 272           failure_message,
 273           "Received an unexpected permessage-deflate extension parameter");
 274     }
 275     const std::string rest(name, kPrefixLen);
 276     if (rest == kNoContextTakeover) {
 277       if (it->HasValue()) {
 278         return DeflateError(failure_message,
 279                             "Received invalid " + name + " parameter");
 280       }
 281       if (is_client)
 282         params->deflate_mode = WebSocketDeflater::DO_NOT_TAKE_OVER_CONTEXT;
 283     } else if (rest == kMaxWindowBits) {
 284       if (!it->HasValue())
 285         return DeflateError(failure_message, name + " must have value");
 286       int bits = 0;
 287       if (!base::StringToInt(it->value(), &bits) || bits < 8 || bits > 15 ||
 288           it->value()[0] == '0' ||
 289           it->value().find_first_not_of("0123456789") != std::string::npos) {
 290         return DeflateError(failure_message,
 291                             "Received invalid " + name + " parameter");
 292       }
 293       if (is_client)
 294         params->client_window_bits = bits;
 295     } else {
 296       return DeflateError(
 297           failure_message,
 298           "Received an unexpected permessage-deflate extension parameter");
 299     }
 300   }
 301   params->deflate_enabled = true;
 302   return true;
 303 }
 304
 305 bool ValidateExtensions(const HttpResponseHeaders* headers,
 306                         const std::vector<std::string>& requested_extensions,
 307                         std::string* extensions,
 308                         std::string* failure_message,
 309                         WebSocketExtensionParams* params) {
 310   void* state = nullptr;
 311   std::string value;
 312   std::vector<std::string> accepted_extensions;
 313   // TODO(ricea): If adding support for additional extensions, generalise this
 314   // code.
 315   bool seen_permessage_deflate = false;
 316   while (headers->EnumerateHeader(
 317              &state, websockets::kSecWebSocketExtensions, &value)) {
 318     WebSocketExtensionParser parser;
 319     parser.Parse(value);
 320     if (parser.has_error()) {
 321       // TODO(yhirano) Set appropriate failure message.
 322       *failure_message =
 323           "'Sec-WebSocket-Extensions' header value is "
 324           "rejected by the parser: " +
 325           value;
 326       return false;
 327     }
 328     if (parser.extension().name() == "permessage-deflate") {
 329       if (seen_permessage_deflate) {
 330         *failure_message = "Received duplicate permessage-deflate response";
 331         return false;
 332       }
 333       seen_permessage_deflate = true;
 334       if (!ValidatePerMessageDeflateExtension(
 335               parser.extension(), failure_message, params))
 336         return false;
 337     } else {
 338       *failure_message =
 339           "Found an unsupported extension '" +
 340           parser.extension().name() +
 341           "' in 'Sec-WebSocket-Extensions' header";
 342       return false;
 343     }
 344     accepted_extensions.push_back(value);
 345   }
 346   *extensions = JoinString(accepted_extensions, ", ");
 347   return true;
 348 }
 349
 350 }  // namespace
 351
 352 WebSocketBasicHandshakeStream::WebSocketBasicHandshakeStream(
 353     scoped_ptr<ClientSocketHandle> connection,
 354     WebSocketStream::ConnectDelegate* connect_delegate,
 355     bool using_proxy,
 356     std::vector<std::string> requested_sub_protocols,
 357     std::vector<std::string> requested_extensions,
 358     std::string* failure_message)
 359     : state_(connection.release(), using_proxy),
 360       connect_delegate_(connect_delegate),
 361       http_response_info_(nullptr),
 362       requested_sub_protocols_(requested_sub_protocols),
 363       requested_extensions_(requested_extensions),
 364       failure_message_(failure_message) {
 365   DCHECK(connect_delegate);
 366   DCHECK(failure_message);
 367 }
 368
 369 WebSocketBasicHandshakeStream::~WebSocketBasicHandshakeStream() {}
 370
 371 int WebSocketBasicHandshakeStream::InitializeStream(
 372     const HttpRequestInfo* request_info,
 373     RequestPriority priority,
 374     const BoundNetLog& net_log,
 375     const CompletionCallback& callback) {
 376   url_ = request_info->url;
 377   state_.Initialize(request_info, priority, net_log, callback);
 378   return OK;
 379 }
 380
 381 int WebSocketBasicHandshakeStream::SendRequest(
 382     const HttpRequestHeaders& headers,
 383     HttpResponseInfo* response,
 384     const CompletionCallback& callback) {
 385   DCHECK(!headers.HasHeader(websockets::kSecWebSocketKey));
 386   DCHECK(!headers.HasHeader(websockets::kSecWebSocketProtocol));
 387   DCHECK(!headers.HasHeader(websockets::kSecWebSocketExtensions));
 388   DCHECK(headers.HasHeader(HttpRequestHeaders::kOrigin));
 389   DCHECK(headers.HasHeader(websockets::kUpgrade));
 390   DCHECK(headers.HasHeader(HttpRequestHeaders::kConnection));
 391   DCHECK(headers.HasHeader(websockets::kSecWebSocketVersion));
 392   DCHECK(parser());
 393
 394   http_response_info_ = response;
 395
 396   // Create a copy of the headers object, so that we can add the
 397   // Sec-WebSockey-Key header.
 398   HttpRequestHeaders enriched_headers;
 399   enriched_headers.CopyFrom(headers);
 400   std::string handshake_challenge;
 401   if (handshake_challenge_for_testing_) {
 402     handshake_challenge = *handshake_challenge_for_testing_;
 403     handshake_challenge_for_testing_.reset();
 404   } else {
 405     handshake_challenge = GenerateHandshakeChallenge();
 406   }
 407   enriched_headers.SetHeader(websockets::kSecWebSocketKey, handshake_challenge);
 408
 409   AddVectorHeaderIfNonEmpty(websockets::kSecWebSocketExtensions,
 410                             requested_extensions_,
 411                             &enriched_headers);
 412   AddVectorHeaderIfNonEmpty(websockets::kSecWebSocketProtocol,
 413                             requested_sub_protocols_,
 414                             &enriched_headers);
 415
 416   handshake_challenge_response_ =
 417       ComputeSecWebSocketAccept(handshake_challenge);
 418
 419   DCHECK(connect_delegate_);
 420   scoped_ptr<WebSocketHandshakeRequestInfo> request(
 421       new WebSocketHandshakeRequestInfo(url_, base::Time::Now()));
 422   request->headers.CopyFrom(enriched_headers);
 423   connect_delegate_->OnStartOpeningHandshake(request.Pass());
 424
 425   return parser()->SendRequest(
 426       state_.GenerateRequestLine(), enriched_headers, response, callback);
 427 }
 428
 429 int WebSocketBasicHandshakeStream::ReadResponseHeaders(
 430     const CompletionCallback& callback) {
 431   // HttpStreamParser uses a weak pointer when reading from the
 432   // socket, so it won't be called back after being destroyed. The
 433   // HttpStreamParser is owned by HttpBasicState which is owned by this object,
 434   // so this use of base::Unretained() is safe.
 435   int rv = parser()->ReadResponseHeaders(
 436       base::Bind(&WebSocketBasicHandshakeStream::ReadResponseHeadersCallback,
 437                  base::Unretained(this),
 438                  callback));
 439   if (rv == ERR_IO_PENDING)
 440     return rv;
 441   return ValidateResponse(rv);
 442 }
 443
 444 int WebSocketBasicHandshakeStream::ReadResponseBody(
 445     IOBuffer* buf,
 446     int buf_len,
 447     const CompletionCallback& callback) {
 448   return parser()->ReadResponseBody(buf, buf_len, callback);
 449 }
 450
 451 void WebSocketBasicHandshakeStream::Close(bool not_reusable) {
 452   // This class ignores the value of |not_reusable| and never lets the socket be
 453   // re-used.
 454   if (parser())
 455     parser()->Close(true);
 456 }
 457
 458 bool WebSocketBasicHandshakeStream::IsResponseBodyComplete() const {
 459   return parser()->IsResponseBodyComplete();
 460 }
 461
 462 bool WebSocketBasicHandshakeStream::CanFindEndOfResponse() const {
 463   return parser() && parser()->CanFindEndOfResponse();
 464 }
 465
 466 bool WebSocketBasicHandshakeStream::IsConnectionReused() const {
 467   return parser()->IsConnectionReused();
 468 }
 469
 470 void WebSocketBasicHandshakeStream::SetConnectionReused() {
 471   parser()->SetConnectionReused();
 472 }
 473
 474 bool WebSocketBasicHandshakeStream::IsConnectionReusable() const {
 475   return false;
 476 }
 477
 478 int64 WebSocketBasicHandshakeStream::GetTotalReceivedBytes() const {
 479   return 0;
 480 }
 481
 482 bool WebSocketBasicHandshakeStream::GetLoadTimingInfo(
 483     LoadTimingInfo* load_timing_info) const {
 484   return state_.connection()->GetLoadTimingInfo(IsConnectionReused(),
 485                                                 load_timing_info);
 486 }
 487
 488 void WebSocketBasicHandshakeStream::GetSSLInfo(SSLInfo* ssl_info) {
 489   parser()->GetSSLInfo(ssl_info);
 490 }
 491
 492 void WebSocketBasicHandshakeStream::GetSSLCertRequestInfo(
 493     SSLCertRequestInfo* cert_request_info) {
 494   parser()->GetSSLCertRequestInfo(cert_request_info);
 495 }
 496
 497 bool WebSocketBasicHandshakeStream::IsSpdyHttpStream() const { return false; }
 498
 499 void WebSocketBasicHandshakeStream::Drain(HttpNetworkSession* session) {
 500   HttpResponseBodyDrainer* drainer = new HttpResponseBodyDrainer(this);
 501   drainer->Start(session);
 502   // |drainer| will delete itself.
 503 }
 504
 505 void WebSocketBasicHandshakeStream::SetPriority(RequestPriority priority) {
 506   // TODO(ricea): See TODO comment in HttpBasicStream::SetPriority(). If it is
 507   // gone, then copy whatever has happened there over here.
 508 }
 509
 510 UploadProgress WebSocketBasicHandshakeStream::GetUploadProgress() const {
 511   return UploadProgress();
 512 }
 513
 514 HttpStream* WebSocketBasicHandshakeStream::RenewStreamForAuth() {
 515   // Return null because we don't support renewing the stream.
 516   return nullptr;
 517 }
 518
 519 scoped_ptr<WebSocketStream> WebSocketBasicHandshakeStream::Upgrade() {
 520   // The HttpStreamParser object has a pointer to our ClientSocketHandle. Make
 521   // sure it does not touch it again before it is destroyed.
 522   state_.DeleteParser();
 523   WebSocketTransportClientSocketPool::UnlockEndpoint(state_.connection());
 524   scoped_ptr<WebSocketStream> basic_stream(
 525       new WebSocketBasicStream(state_.ReleaseConnection(),
 526                                state_.read_buf(),
 527                                sub_protocol_,
 528                                extensions_));
 529   DCHECK(extension_params_.get());
 530   if (extension_params_->deflate_enabled) {
 531     UMA_HISTOGRAM_ENUMERATION(
 532         "Net.WebSocket.DeflateMode",
 533         extension_params_->deflate_mode,
 534         WebSocketDeflater::NUM_CONTEXT_TAKEOVER_MODE_TYPES);
 535
 536     return scoped_ptr<WebSocketStream>(
 537         new WebSocketDeflateStream(basic_stream.Pass(),
 538                                    extension_params_->deflate_mode,
 539                                    extension_params_->client_window_bits,
 540                                    scoped_ptr<WebSocketDeflatePredictor>(
 541                                        new WebSocketDeflatePredictorImpl)));
 542   } else {
 543     return basic_stream.Pass();
 544   }
 545 }
 546
 547 void WebSocketBasicHandshakeStream::SetWebSocketKeyForTesting(
 548     const std::string& key) {
 549   handshake_challenge_for_testing_.reset(new std::string(key));
 550 }
 551
 552 void WebSocketBasicHandshakeStream::ReadResponseHeadersCallback(
 553     const CompletionCallback& callback,
 554     int result) {
 555   callback.Run(ValidateResponse(result));
 556 }
 557
 558 void WebSocketBasicHandshakeStream::OnFinishOpeningHandshake() {
 559   DCHECK(http_response_info_);
 560   WebSocketDispatchOnFinishOpeningHandshake(connect_delegate_,
 561                                             url_,
 562                                             http_response_info_->headers,
 563                                             http_response_info_->response_time);
 564 }
 565
 566 int WebSocketBasicHandshakeStream::ValidateResponse(int rv) {
 567   DCHECK(http_response_info_);
 568   // Most net errors happen during connection, so they are not seen by this
 569   // method. The histogram for error codes is created in
 570   // Delegate::OnResponseStarted in websocket_stream.cc instead.
 571   if (rv >= 0) {
 572     const HttpResponseHeaders* headers = http_response_info_->headers.get();
 573     const int response_code = headers->response_code();
 574     UMA_HISTOGRAM_SPARSE_SLOWLY("Net.WebSocket.ResponseCode", response_code);
 575     switch (response_code) {
 576       case HTTP_SWITCHING_PROTOCOLS:
 577         OnFinishOpeningHandshake();
 578         return ValidateUpgradeResponse(headers);
 579
 580       // We need to pass these through for authentication to work.
 581       case HTTP_UNAUTHORIZED:
 582       case HTTP_PROXY_AUTHENTICATION_REQUIRED:
 583         return OK;
 584
 585       // Other status codes are potentially risky (see the warnings in the
 586       // WHATWG WebSocket API spec) and so are dropped by default.
 587       default:
 588         // A WebSocket server cannot be using HTTP/0.9, so if we see version
 589         // 0.9, it means the response was garbage.
 590         // Reporting "Unexpected response code: 200" in this case is not
 591         // helpful, so use a different error message.
 592         if (headers->GetHttpVersion() == HttpVersion(0, 9)) {
 593           set_failure_message(
 594               "Error during WebSocket handshake: Invalid status line");
 595         } else {
 596           set_failure_message(base::StringPrintf(
 597               "Error during WebSocket handshake: Unexpected response code: %d",
 598               headers->response_code()));
 599         }
 600         OnFinishOpeningHandshake();
 601         return ERR_INVALID_RESPONSE;
 602     }
 603   } else {
 604     if (rv == ERR_EMPTY_RESPONSE) {
 605       set_failure_message(
 606           "Connection closed before receiving a handshake response");
 607       return rv;
 608     }
 609     set_failure_message(std::string("Error during WebSocket handshake: ") +
 610                         ErrorToString(rv));
 611     OnFinishOpeningHandshake();
 612     // Some error codes (for example ERR_CONNECTION_CLOSED) get changed to OK at
 613     // higher levels. To prevent an unvalidated connection getting erroneously
 614     // upgraded, don't pass through the status code unchanged if it is
 615     // HTTP_SWITCHING_PROTOCOLS.
 616     if (http_response_info_->headers &&
 617         http_response_info_->headers->response_code() ==
 618             HTTP_SWITCHING_PROTOCOLS) {
 619       http_response_info_->headers->ReplaceStatusLine(
 620           kConnectionErrorStatusLine);
 621     }
 622     return rv;
 623   }
 624 }
 625
 626 int WebSocketBasicHandshakeStream::ValidateUpgradeResponse(
 627     const HttpResponseHeaders* headers) {
 628   extension_params_.reset(new WebSocketExtensionParams);
 629   std::string failure_message;
 630   if (ValidateUpgrade(headers, &failure_message) &&
 631       ValidateSecWebSocketAccept(
 632           headers, handshake_challenge_response_, &failure_message) &&
 633       ValidateConnection(headers, &failure_message) &&
 634       ValidateSubProtocol(headers,
 635                           requested_sub_protocols_,
 636                           &sub_protocol_,
 637                           &failure_message) &&
 638       ValidateExtensions(headers,
 639                          requested_extensions_,
 640                          &extensions_,
 641                          &failure_message,
 642                          extension_params_.get())) {
 643     return OK;
 644   }
 645   set_failure_message("Error during WebSocket handshake: " + failure_message);
 646   return ERR_INVALID_RESPONSE;
 647 }
 648
 649 void WebSocketBasicHandshakeStream::set_failure_message(
 650     const std::string& failure_message) {
 651   *failure_message_ = failure_message;
 652 }
 653
 654 }  // namespace net