boost asio ssl writing part of data - c++

Question

My client-server app, that communicating through boost asio, usign functions:
When connection starts, client send to server bunch of requests, server send back some response.
After adding asio::ssl to project i get following problem.
Sometimes, 1/5 times, server reads only first fixed part of requests. When client disconnected, server get all missed requests.
On client side all seems good, callbakcs called with no errors and writed sizes are proper. But result from packet sniffer show that client not sending this part of requests.
Client :
Size of each "frame" located in header, first must read atleast header.
Thread Worker used for background work, and pushing ready packets to storage.
using SSLSocket = boost::asio::ssl::stream<boost::asio::ip::tcp::socket>;
class AsyncStrategy :
public NetworkStrategy
{
// other data...
void _WriteHandler(const boost::system::error_code& err, size_t bytes);
bool Connect(const boost::asio::ip::tcp::endpoint& endpoint);
void _BindMessage();
void _BindMessageRemainder(size_t size);
void _AcceptMessage(const boost::system::error_code& err_code, size_t bytes);
void _AcceptMessageRemainder(const boost::system::error_code& err_code, size_t bytes);
// to keep io_service running
void _BindTimer();
void _DumpTimer(const boost::system::error_code& error);
void _SolveProblem(const boost::system::error_code& err_code);
void _Disconnect();
bool verify_certificate(bool preverified,
boost::asio::ssl::verify_context& ctx);
PacketQuery query;
boost::array <Byte, PacketMaxSize> WriteBuff;
boost::array <Byte, PacketMaxSize> ReadBuff;
boost::asio::ip::tcp::endpoint ep;
boost::asio::io_service service;
boost::asio::deadline_timer _Timer{ service };
boost::asio::ssl::context _SSLContext;
SSLSocket sock;
boost::thread Worker;
bool _ThreadWorking;
bool _Connected = false;
};
AsyncStrategy::AsyncStrategy( MessengerAPI& api)
: API{api},_SSLContext{service,boost::asio::ssl::context::sslv23 },
sock{ service,_SSLContext }, _Timer{service},
Worker{ [&]() {
_BindTimer();
service.run();
} },
_ThreadWorking{ true }
{
_SSLContext.set_verify_mode(boost::asio::ssl::verify_peer);
_SSLContext.set_verify_callback(
boost::bind(&AsyncStrategy::verify_certificate, this, _1, _2));
_SSLContext.load_verify_file("ca.pem");
}
bool AsyncStrategy::verify_certificate(bool preverified,
boost::asio::ssl::verify_context& ctx)
{
return preverified;
}
void AsyncStrategy::_BindMessage()
{
boost::asio::async_read(sock, buffer(ReadBuff,BaseHeader::HeaderSize()),
boost::bind(&AsyncStrategy::_AcceptMessage, this, _1, _2));
}
bool AsyncStrategy::Connect(const boost::asio::ip::tcp::endpoint& endpoint)
{
ep = endpoint;
boost::system::error_code err;
sock.lowest_layer().connect(ep, err);
if (err)
throw __ConnectionRefused{};
// need blocking handshake
sock.handshake(boost::asio::ssl::stream_base::client, err);
if (err)
throw __ConnectionRefused{};
_BindMessage();
return true;
}
void AsyncStrategy::_AcceptMessage(const boost::system::error_code& err_code, size_t bytes)
{
// checking header, to see, packet ends or not
// if there is more data in packet, read rest my binding function
// pseudocode
if( need_load_more )
_BindMessageRemainder(BytesToReceive(FrameSize));
return;
}
// if not use this bind this function next time
_CheckPacket(ReadBuff.c_array(), bytes);
_BindMessage();
}
void AsyncStrategy::_AcceptMessageRemainder(const boost::system::error_code& err_code, size_t bytes)
{
if (err_code)
{
_SolveProblem(err_code);
return;
}
_CheckPacket(ReadBuff.c_array(), bytes + BaseHeader::HeaderSize());
_BindMessage();
}
bool AsyncStrategy::Send(const TransferredData& Data)
{
// alreay known, that that data fits in buffer
Data.ToBuffer(WriteBuff.c_array());
boost::asio::async_write(sock,
buffer(WriteBuff, Data.NeededSize()),
boost::bind(&AsyncStrategy::_WriteHandler, this, _1, _2));
return true;
}
void AsyncStrategy::_WriteHandler(const boost::system::error_code& err, size_t bytes)
{
if (err)
_SolveProblem(err);
}
After removing all ssl stuff, data transfer is normal. As i mentioned, all works properly before ssl integration.
Finding solution, i discovered that if send with delay, tried 200 ms, all data transferring normally.
Win10, boost 1.60, OpenSSL 1.0.2n
I guess there may be an error in my code, but I tried almost everything I thought. Looking for advice.

Answer 1

We can't see how Send is actually called.
Perhaps it needs to be synchronized.
We can that it reuses the same buffer each time, so two writes overlapping will clobber that buffer.
We can also see that you're not verifying that the size of the Data argument fits into the PacketMaxSize buffer.
This means you will not only lose data if you exceed the expected buffer size, it will also invoke Undefined Behaviour