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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/server/web_socket.h"
#include <vector>
#include "base/base64.h"
#include "base/check.h"
#include "base/hash/sha1.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "base/sys_byteorder.h"
#include "net/server/http_connection.h"
#include "net/server/http_server.h"
#include "net/server/http_server_request_info.h"
#include "net/server/http_server_response_info.h"
#include "net/server/web_socket_encoder.h"
#include "net/websockets/websocket_deflate_parameters.h"
#include "net/websockets/websocket_extension.h"
#include "net/websockets/websocket_handshake_constants.h"
namespace net {
namespace {
std::string ExtensionsHeaderString(
const std::vector<WebSocketExtension>& extensions) {
if (extensions.empty())
return std::string();
std::string result = "Sec-WebSocket-Extensions: " + extensions[0].ToString();
for (size_t i = 1; i < extensions.size(); ++i)
result += ", " + extensions[i].ToString();
return result + "\r\n";
}
std::string ValidResponseString(
const std::string& accept_hash,
const std::vector<WebSocketExtension> extensions) {
return base::StringPrintf(
"HTTP/1.1 101 WebSocket Protocol Handshake\r\n"
"Upgrade: WebSocket\r\n"
"Connection: Upgrade\r\n"
"Sec-WebSocket-Accept: %s\r\n"
"%s"
"\r\n",
accept_hash.c_str(), ExtensionsHeaderString(extensions).c_str());
}
} // namespace
WebSocket::WebSocket(HttpServer* server, HttpConnection* connection)
: server_(server), connection_(connection) {}
WebSocket::~WebSocket() = default;
void WebSocket::Accept(const HttpServerRequestInfo& request,
const NetworkTrafficAnnotationTag traffic_annotation) {
std::string version = request.GetHeaderValue("sec-websocket-version");
if (version != "8" && version != "13") {
SendErrorResponse("Invalid request format. The version is not valid.",
traffic_annotation);
return;
}
std::string key = request.GetHeaderValue("sec-websocket-key");
if (key.empty()) {
SendErrorResponse(
"Invalid request format. Sec-WebSocket-Key is empty or isn't "
"specified.",
traffic_annotation);
return;
}
std::string encoded_hash;
base::Base64Encode(base::SHA1HashString(key + websockets::kWebSocketGuid),
&encoded_hash);
std::vector<WebSocketExtension> response_extensions;
auto i = request.headers.find("sec-websocket-extensions");
if (i == request.headers.end()) {
encoder_ = WebSocketEncoder::CreateServer();
} else {
WebSocketDeflateParameters params;
encoder_ = WebSocketEncoder::CreateServer(i->second, ¶ms);
if (!encoder_) {
Fail();
return;
}
if (encoder_->deflate_enabled()) {
DCHECK(params.IsValidAsResponse());
response_extensions.push_back(params.AsExtension());
}
}
server_->SendRaw(connection_->id(),
ValidResponseString(encoded_hash, response_extensions),
traffic_annotation);
traffic_annotation_ = std::make_unique<NetworkTrafficAnnotationTag>(
NetworkTrafficAnnotationTag(traffic_annotation));
}
WebSocket::ParseResult WebSocket::Read(std::string* message) {
if (closed_)
return FRAME_CLOSE;
if (!encoder_) {
// RFC6455, section 4.1 says "Once the client's opening handshake has been
// sent, the client MUST wait for a response from the server before sending
// any further data". If |encoder_| is null here, ::Accept either has not
// been called at all, or has rejected a request rather than producing
// a server handshake. Either way, the client clearly couldn't have gotten
// a proper server handshake, so error out, especially since this method
// can't proceed without an |encoder_|.
return FRAME_ERROR;
}
ParseResult result = FRAME_OK_MIDDLE;
HttpConnection::ReadIOBuffer* read_buf = connection_->read_buf();
base::StringPiece frame(read_buf->StartOfBuffer(), read_buf->GetSize());
int bytes_consumed = 0;
result = encoder_->DecodeFrame(frame, &bytes_consumed, message);
read_buf->DidConsume(bytes_consumed);
if (result == FRAME_CLOSE) {
// The current websocket implementation does not initiate the Close
// handshake before closing the connection.
// Therefore the received Close frame most likely belongs to the client that
// initiated the Closing handshake.
// According to https://datatracker.ietf.org/doc/html/rfc6455#section-5.5.1
// if an endpoint receives a Close frame and did not previously send a
// Close frame, the endpoint MUST send a Close frame in response.
// It also MAY provide the close reason listed in
// https://datatracker.ietf.org/doc/html/rfc6455#section-7.4.1.
// As the closure was initiated by the client the "normal closure" status
// code is appropriate.
std::string code = "\x03\xe8"; // code = 1000;
std::string encoded;
encoder_->EncodeCloseFrame(code, 0, &encoded);
server_->SendRaw(connection_->id(), encoded, *traffic_annotation_);
closed_ = true;
}
if (result == FRAME_PING) {
if (!traffic_annotation_)
return FRAME_ERROR;
Send(*message, WebSocketFrameHeader::kOpCodePong, *traffic_annotation_);
}
return result;
}
void WebSocket::Send(base::StringPiece message,
WebSocketFrameHeader::OpCodeEnum op_code,
const NetworkTrafficAnnotationTag traffic_annotation) {
if (closed_)
return;
std::string encoded;
switch (op_code) {
case WebSocketFrameHeader::kOpCodeText:
encoder_->EncodeTextFrame(message, 0, &encoded);
break;
case WebSocketFrameHeader::kOpCodePong:
encoder_->EncodePongFrame(message, 0, &encoded);
break;
default:
// Only Pong and Text frame types are supported.
NOTREACHED();
}
server_->SendRaw(connection_->id(), encoded, traffic_annotation);
}
void WebSocket::Fail() {
closed_ = true;
// TODO(yhirano): The server SHOULD log the problem.
server_->Close(connection_->id());
}
void WebSocket::SendErrorResponse(
const std::string& message,
const NetworkTrafficAnnotationTag traffic_annotation) {
if (closed_)
return;
closed_ = true;
server_->Send500(connection_->id(), message, traffic_annotation);
}
} // namespace net
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