libreoffice-online/net/WebSocketHandler.hpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#ifndef INCLUDED_WEBSOCKETHANDLER_HPP
#define INCLUDED_WEBSOCKETHANDLER_HPP
#include <chrono>
#include <memory>
#include <vector>
#include "common/Common.hpp"
#include "common/Log.hpp"
#include "common/Unit.hpp"
#include "Socket.hpp"
#include <Poco/MemoryStream.h>
#include <Poco/Net/HTTPRequest.h>
#include <Poco/Net/HTTPResponse.h>
#include <Poco/Net/WebSocket.h>
class WebSocketHandler : public SocketHandlerInterface
{
protected:
/// The socket that owns us (we can't own it).
std::weak_ptr<StreamSocket> _socket;
std::chrono::steady_clock::time_point _lastPingSentTime;
int _pingTimeUs;
std::vector<char> _wsPayload;
std::atomic<bool> _shuttingDown;
bool _isClient;
bool _isMasking;
struct WSFrameMask
{
static const unsigned char Fin = 0x80;
static const unsigned char Mask = 0x80;
};
static const int InitialPingDelayMs = 25;
static const int PingFrequencyMs = 18 * 1000;
public:
/// Perform upgrade ourselves, or select a client web socket.
WebSocketHandler(bool isClient = false, bool isMasking = true) :
_lastPingSentTime(std::chrono::steady_clock::now()),
_pingTimeUs(0),
_shuttingDown(false),
_isClient(isClient),
_isMasking(isClient && isMasking)
{
}
/// Upgrades itself to a websocket directly.
WebSocketHandler(const std::weak_ptr<StreamSocket>& socket,
const Poco::Net::HTTPRequest& request) :
_socket(socket),
_lastPingSentTime(std::chrono::steady_clock::now() -
std::chrono::milliseconds(PingFrequencyMs) -
std::chrono::milliseconds(InitialPingDelayMs)),
_pingTimeUs(0),
_shuttingDown(false),
_isClient(false),
_isMasking(false)
{
upgradeToWebSocket(request);
}
/// Implementation of the SocketHandlerInterface.
void onConnect(const std::shared_ptr<StreamSocket>& socket) override
{
_socket = socket;
LOG_TRC("#" << socket->getFD() << " Connected to WS Handler 0x" << std::hex << this << std::dec);
}
/// Status codes sent to peer on shutdown.
enum class StatusCodes : unsigned short
{
NORMAL_CLOSE = 1000,
ENDPOINT_GOING_AWAY = 1001,
PROTOCOL_ERROR = 1002,
PAYLOAD_NOT_ACCEPTABLE = 1003,
RESERVED = 1004,
RESERVED_NO_STATUS_CODE = 1005,
RESERVED_ABNORMAL_CLOSE = 1006,
MALFORMED_PAYLOAD = 1007,
POLICY_VIOLATION = 1008,
PAYLOAD_TOO_BIG = 1009,
EXTENSION_REQUIRED = 1010,
UNEXPECTED_CONDITION = 1011,
RESERVED_TLS_FAILURE = 1015
};
/// Sends WS shutdown message to the peer.
void shutdown(const StatusCodes statusCode = StatusCodes::NORMAL_CLOSE, const std::string& statusMessage = "")
{
std::shared_ptr<StreamSocket> socket = _socket.lock();
if (socket == nullptr)
{
LOG_ERR("No socket associated with WebSocketHandler 0x" << std::hex << this << std::dec);
return;
}
LOG_TRC("#" << socket->getFD() << ": Shutdown websocket, code: " <<
static_cast<unsigned>(statusCode) << ", message: " << statusMessage);
_shuttingDown = true;
const size_t len = statusMessage.size();
std::vector<char> buf(2 + len);
buf[0] = ((((int)statusCode) >> 8) & 0xff);
buf[1] = ((((int)statusCode) >> 0) & 0xff);
std::copy(statusMessage.begin(), statusMessage.end(), buf.begin() + 2);
const unsigned char flags = WSFrameMask::Fin
| static_cast<char>(WSOpCode::Close);
sendFrame(socket, buf.data(), buf.size(), flags);
}
bool handleOneIncomingMessage(const std::shared_ptr<StreamSocket>& socket)
{
assert(socket && "Expected a valid socket instance.");
// websocket fun !
const size_t len = socket->_inBuffer.size();
if (len == 0)
return false; // avoid logging.
if (len < 2) // partial read
{
LOG_TRC("#" << socket->getFD() << ": Still incomplete WebSocket message, have " << len << " bytes");
return false;
}
unsigned char *p = reinterpret_cast<unsigned char*>(&socket->_inBuffer[0]);
const bool fin = p[0] & 0x80;
const WSOpCode code = static_cast<WSOpCode>(p[0] & 0x0f);
const bool hasMask = p[1] & 0x80;
size_t payloadLen = p[1] & 0x7f;
size_t headerLen = 2;
// normally - 7 bit length.
if (payloadLen == 126) // 2 byte length
{
if (len < 2 + 2)
{
LOG_TRC("#" << socket->getFD() << ": Still incomplete WebSocket message, have " << len << " bytes");
return false;
}
payloadLen = (((unsigned)p[2]) << 8) | ((unsigned)p[3]);
headerLen += 2;
}
else if (payloadLen == 127) // 8 byte length
{
if (len < 2 + 8)
{
LOG_TRC("#" << socket->getFD() << ": Still incomplete WebSocket message, have " << len << " bytes");
return false;
}
payloadLen = ((((uint64_t)p[9]) << 0) + (((uint64_t)p[8]) << 8) +
(((uint64_t)p[7]) << 16) + (((uint64_t)p[6]) << 24) +
(((uint64_t)p[5]) << 32) + (((uint64_t)p[4]) << 40) +
(((uint64_t)p[3]) << 48) + (((uint64_t)p[2]) << 56));
// FIXME: crop read length to remove top / sign bits.
headerLen += 8;
}
unsigned char *data, *mask;
if (hasMask)
{
mask = p + headerLen;
headerLen += 4;
}
if (payloadLen + headerLen > len)
{ // partial read wait for more data.
LOG_TRC("#" << socket->getFD() << ": Still incomplete WebSocket message, have " << len << " bytes, message is " << payloadLen + headerLen << " bytes");
return false;
}
LOG_TRC("#" << socket->getFD() << ": Incoming WebSocket data of " << len << " bytes: " << Util::stringifyHexLine(socket->_inBuffer, 0, std::min((size_t)32, len)));
data = p + headerLen;
if (hasMask)
{
const size_t end = _wsPayload.size();
_wsPayload.resize(end + payloadLen);
char* wsData = &_wsPayload[end];
for (size_t i = 0; i < payloadLen; ++i)
*wsData++ = data[i] ^ mask[i % 4];
} else
_wsPayload.insert(_wsPayload.end(), data, data + payloadLen);
assert(_wsPayload.size() >= payloadLen);
socket->_inBuffer.erase(socket->_inBuffer.begin(), socket->_inBuffer.begin() + headerLen + payloadLen);
// FIXME: fin, aggregating payloads into _wsPayload etc.
LOG_TRC("#" << socket->getFD() << ": Incoming WebSocket message code " << static_cast<unsigned>(code) <<
", fin? " << fin << ", mask? " << hasMask << ", payload length: " << _wsPayload.size() <<
", residual socket data: " << socket->_inBuffer.size() << " bytes.");
bool doClose = false;
switch (code)
{
case WSOpCode::Pong:
{
if (_isClient)
{
LOG_ERR("#" << socket->getFD() << ": Servers should not send pongs, only clients");
doClose = true;
break;
}
else
{
_pingTimeUs = std::chrono::duration_cast<std::chrono::microseconds>
(std::chrono::steady_clock::now() - _lastPingSentTime).count();
LOG_TRC("#" << socket->getFD() << ": Pong received: " << _pingTimeUs << " microseconds");
break;
}
}
case WSOpCode::Ping:
if (_isClient)
{
auto now = std::chrono::steady_clock::now();
_pingTimeUs = std::chrono::duration_cast<std::chrono::microseconds>
(now - _lastPingSentTime).count();
sendPong(now, &_wsPayload[0], payloadLen, socket);
break;
}
else
{
LOG_ERR("#" << socket->getFD() << ": Clients should not send pings, only servers");
doClose = true;
}
break;
case WSOpCode::Close:
doClose = true;
break;
default:
handleMessage(fin, code, _wsPayload);
break;
}
if (doClose)
{
if (!_shuttingDown)
{
// Peer-initiated shutdown must be echoed.
// Otherwise, this is the echo to _our_ shutdown message, which we should ignore.
const StatusCodes statusCode = static_cast<StatusCodes>((((uint64_t)(unsigned char)_wsPayload[0]) << 8) +
(((uint64_t)(unsigned char)_wsPayload[1]) << 0));
LOG_TRC("#" << socket->getFD() << ": Client initiated socket shutdown. Code: " << static_cast<int>(statusCode));
if (_wsPayload.size() > 2)
{
const std::string message(&_wsPayload[2], &_wsPayload[2] + _wsPayload.size() - 2);
shutdown(statusCode, message);
}
else
{
shutdown(statusCode);
}
}
else
{
LOG_TRC("#" << socket->getFD() << ": Client responded to our shutdown.");
}
// TCP Close.
socket->closeConnection();
}
_wsPayload.clear();
return true;
}
/// Implementation of the SocketHandlerInterface.
virtual void handleIncomingMessage(SocketDisposition&) override
{
std::shared_ptr<StreamSocket> socket = _socket.lock();
if (socket == nullptr)
{
LOG_ERR("No socket associated with WebSocketHandler 0x" << std::hex << this << std::dec);
}
else if (_isClient && !socket->isWebSocket())
handleClientUpgrade();
else
{
while (handleOneIncomingMessage(socket))
; // might have multiple messages in the accumulated buffer.
}
}
int getPollEvents(std::chrono::steady_clock::time_point now,
int & timeoutMaxMs) override
{
if (!_isClient)
{
const int timeSincePingMs =
std::chrono::duration_cast<std::chrono::milliseconds>(now - _lastPingSentTime).count();
timeoutMaxMs = std::min(timeoutMaxMs, PingFrequencyMs - timeSincePingMs);
}
return POLLIN;
}
/// Send a ping message
void sendPingOrPong(std::chrono::steady_clock::time_point now,
const char* data, const size_t len,
const WSOpCode code,
const std::shared_ptr<StreamSocket>& socket)
{
assert(socket && "Expected a valid socket instance.");
// Must not send this before we're upgraded.
if (!socket->isWebSocket())
{
LOG_WRN("Attempted ping on non-upgraded websocket! #" << socket->getFD());
_lastPingSentTime = now; // Pretend we sent it to avoid timing out immediately.
return;
}
LOG_TRC("#" << socket->getFD() << ": Sending " <<
(const char *)(code == WSOpCode::Ping ? " ping." : "pong."));
// FIXME: allow an empty payload.
sendMessage(data, len, code, false);
_lastPingSentTime = now;
}
void sendPing(std::chrono::steady_clock::time_point now,
const std::shared_ptr<StreamSocket>& socket)
{
assert(!_isClient);
sendPingOrPong(now, "", 1, WSOpCode::Ping, socket);
}
void sendPong(std::chrono::steady_clock::time_point now,
const char* data, const size_t len,
const std::shared_ptr<StreamSocket>& socket)
{
assert(_isClient);
sendPingOrPong(now, data, len, WSOpCode::Pong, socket);
}
/// Do we need to handle a timeout ?
void checkTimeout(std::chrono::steady_clock::time_point now) override
{
if (_isClient)
return;
const int timeSincePingMs =
std::chrono::duration_cast<std::chrono::milliseconds>(now - _lastPingSentTime).count();
if (timeSincePingMs >= PingFrequencyMs)
{
const std::shared_ptr<StreamSocket> socket = _socket.lock();
if (socket)
sendPing(now, socket);
}
}
/// By default rely on the socket buffer.
void performWrites() override {}
/// Sends a WebSocket Text message.
int sendMessage(const std::string& msg) const
{
return sendMessage(msg.data(), msg.size(), WSOpCode::Text);
}
/// Sends a WebSocket message of WPOpCode type.
/// Returns the number of bytes written (including frame overhead) on success,
/// 0 for closed/invalid socket, and -1 for other errors.
int sendMessage(const char* data, const size_t len, const WSOpCode code, const bool flush = true) const
{
#ifndef MOBILEAPP
int unitReturn = -1;
if (UnitBase::get().filterSendMessage(data, len, code, flush, unitReturn))
return unitReturn;
#endif
//TODO: Support fragmented messages.
std::shared_ptr<StreamSocket> socket = _socket.lock();
return sendFrame(socket, data, len, WSFrameMask::Fin | static_cast<unsigned char>(code), flush);
}
private:
/// Sends a WebSocket frame given the data, length, and flags.
/// Returns the number of bytes written (including frame overhead) on success,
/// 0 for closed/invalid socket, and -1 for other errors.
int sendFrame(const std::shared_ptr<StreamSocket>& socket,
const char* data, const size_t len,
unsigned char flags, const bool flush = true) const
{
if (!socket || data == nullptr || len == 0)
return -1;
if (socket->isClosed())
return 0;
socket->assertCorrectThread();
std::vector<char>& out = socket->_outBuffer;
const size_t oldSize = out.size();
out.push_back(flags);
int maskFlag = _isMasking ? 0x80 : 0;
if (len < 126)
{
out.push_back((char)(len | maskFlag));
}
else if (len <= 0xffff)
{
out.push_back((char)(126 | maskFlag));
out.push_back(static_cast<char>((len >> 8) & 0xff));
out.push_back(static_cast<char>((len >> 0) & 0xff));
}
else
{
out.push_back((char)(127 | maskFlag));
out.push_back(static_cast<char>((len >> 56) & 0xff));
out.push_back(static_cast<char>((len >> 48) & 0xff));
out.push_back(static_cast<char>((len >> 40) & 0xff));
out.push_back(static_cast<char>((len >> 32) & 0xff));
out.push_back(static_cast<char>((len >> 24) & 0xff));
out.push_back(static_cast<char>((len >> 16) & 0xff));
out.push_back(static_cast<char>((len >> 8) & 0xff));
out.push_back(static_cast<char>((len >> 0) & 0xff));
}
if (_isMasking)
{ // flip some top bits - perhaps it helps.
size_t mask = out.size();
out.push_back(static_cast<char>(0x81));
out.push_back(static_cast<char>(0x76));
out.push_back(static_cast<char>(0x81));
out.push_back(static_cast<char>(0x76));
// Copy the data.
out.insert(out.end(), data, data + len);
// Mask it.
for (size_t i = 4; i < out.size() - mask; ++i)
out[mask + i] = out[mask + i] ^ out[mask + (i%4)];
}
else
{
// Copy the data.
out.insert(out.end(), data, data + len);
}
const size_t size = out.size() - oldSize;
if (flush)
socket->writeOutgoingData();
return size;
}
protected:
/// To be overriden to handle the websocket messages the way you need.
virtual void handleMessage(bool /*fin*/, WSOpCode /*code*/, std::vector<char> &/*data*/)
{
}
void dumpState(std::ostream& os) override;
private:
/// To make the protected 'computeAccept' accessible.
class PublicComputeAccept : public Poco::Net::WebSocket
{
public:
static std::string doComputeAccept(const std::string &key)
{
return computeAccept(key);
}
};
protected:
/// Upgrade the http(s) connection to a websocket.
void upgradeToWebSocket(const Poco::Net::HTTPRequest& req)
{
std::shared_ptr<StreamSocket> socket = _socket.lock();
if (socket == nullptr)
throw std::runtime_error("Invalid socket while upgrading to WebSocket. Request: " + req.getURI());
LOG_TRC("#" << socket->getFD() << ": Upgrading to WebSocket.");
assert(!socket->isWebSocket());
// create our websocket goodness ...
const int wsVersion = std::stoi(req.get("Sec-WebSocket-Version", "13"));
const std::string wsKey = req.get("Sec-WebSocket-Key", "");
const std::string wsProtocol = req.get("Sec-WebSocket-Protocol", "chat");
// FIXME: other sanity checks ...
LOG_INF("#" << socket->getFD() << ": WebSocket version: " << wsVersion <<
", key: [" << wsKey << "], protocol: [" << wsProtocol << "].");
#if ENABLE_DEBUG
if (std::getenv("LOOL_ZERO_BUFFER_SIZE"))
socket->setSocketBufferSize(0);
#endif
std::ostringstream oss;
oss << "HTTP/1.1 101 Switching Protocols\r\n"
<< "Upgrade: websocket\r\n"
<< "Connection: Upgrade\r\n"
<< "Sec-WebSocket-Accept: " << PublicComputeAccept::doComputeAccept(wsKey) << "\r\n"
<< "\r\n";
const std::string res = oss.str();
LOG_TRC("#" << socket->getFD() << ": Sending WS Upgrade response: " << res);
socket->send(res);
setWebSocket();
}
// Handle incoming upgrade to full socket as client WS.
void handleClientUpgrade()
{
std::shared_ptr<StreamSocket> socket = _socket.lock();
LOG_TRC("Incoming client websocket upgrade response: " << std::string(&socket->_inBuffer[0], socket->_inBuffer.size()));
bool bOk = false;
size_t responseSize = 0;
try
{
Poco::MemoryInputStream message(&socket->_inBuffer[0], socket->_inBuffer.size());;
Poco::Net::HTTPResponse response;
response.read(message);
{
static const std::string marker("\r\n\r\n");
auto itBody = std::search(socket->_inBuffer.begin(),
socket->_inBuffer.end(),
marker.begin(), marker.end());
if (itBody != socket->_inBuffer.end())
responseSize = itBody - socket->_inBuffer.begin() + marker.size();
}
if (response.getStatus() == Poco::Net::HTTPResponse::HTTP_SWITCHING_PROTOCOLS &&
response.has("Upgrade") && Poco::icompare(response.get("Upgrade"), "websocket") == 0)
{
#if 0 // SAL_DEBUG ...
const std::string wsKey = response.get("Sec-WebSocket-Accept", "");
const std::string wsProtocol = response.get("Sec-WebSocket-Protocol", "");
if (Poco::icompare(wsProtocol, "chat") != 0)
LOG_ERR("Unknown websocket protocol " << wsProtocol);
else
#endif
{
LOG_TRC("Accepted incoming websocket response");
// FIXME: validate Sec-WebSocket-Accept vs. Sec-WebSocket-Key etc.
bOk = true;
}
}
}
catch (const Poco::Exception& exc)
{
LOG_DBG("handleClientUpgrade exception caught: " << exc.displayText());
}
catch (const std::exception& exc)
{
LOG_DBG("handleClientUpgrade exception caught.");
}
if (!bOk || responseSize == 0)
{
LOG_ERR("Bad websocker server response.");
socket->shutdown();
return;
}
setWebSocket();
socket->eraseFirstInputBytes(responseSize);
}
void setWebSocket()
{
std::shared_ptr<StreamSocket> socket = _socket.lock();
socket->setWebSocket();
// No need to ping right upon connection/upgrade,
// but do reset the time to avoid pinging immediately after.
_lastPingSentTime = std::chrono::steady_clock::now();
}
};
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */