boost asio - write equivalent piece of code - c++

Question

I have this piece of code using standard sockets:
void set_fds(int sock1, int sock2, fd_set *fds) {
FD_ZERO (fds);
FD_SET (sock1, fds);
FD_SET (sock2, fds);
}
void do_proxy(int client, int conn, char *buffer) {
fd_set readfds;
int result, nfds = max(client, conn)+1;
set_fds(client, conn, &readfds);
while((result = select(nfds, &readfds, 0, 0, 0)) > 0) {
if (FD_ISSET (client, &readfds)) {
int recvd = recv(client, buffer, 256, 0);
if(recvd <= 0)
return;
send_sock(conn, buffer, recvd);
}
if (FD_ISSET (conn, &readfds)) {
int recvd = recv(conn, buffer, 256, 0);
if(recvd <= 0)
return;
send_sock(client, buffer, recvd);
}
set_fds(client, conn, &readfds);
}
I have sockets client and conn and I need to "proxy" traffic between them (this is part of a socks5 server implementation, you may see https://github.com/mfontanini/Programs-Scripts/blob/master/socks5/socks5.cpp). How can I achieve this under asio ?
I must specify that until this point both sockets were operated under blocking mode.
Tried to use this without success:
ProxySession::ProxySession(ba::io_service& ioService, socket_ptr socket, socket_ptr clientSock): ioService_(ioService), socket_(socket), clientSock_(clientSock)
{
}
void ProxySession::Start()
{
socket_->async_read_some(boost::asio::buffer(data_, 1),
boost::bind(&ProxySession::HandleProxyRead, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
void ProxySession::HandleProxyRead(const boost::system::error_code& error,
size_t bytes_transferred)
{
if (!error)
{
boost::asio::async_write(*clientSock_,
boost::asio::buffer(data_, bytes_transferred),
boost::bind(&ProxySession::HandleProxyWrite, this,
boost::asio::placeholders::error));
}
else
{
delete this;
}
}
void ProxySession::HandleProxyWrite(const boost::system::error_code& error)
{
if (!error)
{
socket_->async_read_some(boost::asio::buffer(data_, max_length),
boost::bind(&ProxySession::HandleProxyRead, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
else
{
delete this;
}
}
The issue is that if I do ba::read(*socket_, ba::buffer(data_,256)) I can read data that comes from my browser client through socks proxy but in the version from above ProxySession::Start does not lead to HandleProxyRead being called in any circumstances.
I don't really need an async way of exchanging data here, it;s just that I've come by with this solution here. Also from where I called ProxySession->start from code I needed to introduce a sleep because otherwise the thread context from which this was executing was being shut down.
*Update 2 * See below one of my updates. The question block is getting too big.

Answer 1

The problem ca be solved by using asynchronous write/read functions in order to have something similar with presented code. Basically use async_read_some()/async_write() - or other async functions in these categories. Also in order for async processing to work one must call boost::asio::io_service.run() that will dispatch completion handler for async processing.

Answer 2

I have managed to come with this. This solution solves the problem of "data exchange" for the 2 sockets (that must happen acording to socks5 server proxy) but it is very compute intensive. Any ideas ?
std::size_t readable = 0;
boost::asio::socket_base::bytes_readable command1(true);
boost::asio::socket_base::bytes_readable command2(true);
try
{
while (1)
{
socket_->io_control(command1);
clientSock_->io_control(command2);
if ((readable = command1.get()) > 0)
{
transf = ba::read(*socket_, ba::buffer(data_,readable));
ba::write(*clientSock_, ba::buffer(data_,transf));
boost::this_thread::sleep(boost::posix_time::milliseconds(500));
}
if ((readable = command2.get()) > 0)
{
transf = ba::read(*clientSock_, ba::buffer(data_,readable));
ba::write(*socket_, ba::buffer(data_,transf));
boost::this_thread::sleep(boost::posix_time::milliseconds(500));
}
}
}
catch (std::exception& ex)
{
std::cerr << "Exception in thread while exchanging: " << ex.what() << "\n";
return;
}