network_asio.cpp

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/*
   Copyright (C) 2011 - 2016 by Sergey Popov <[email protected]>
   Part of the Battle for Wesnoth Project http://www.wesnoth.org/

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY.

   See the COPYING file for more details.
*/

#include <deque>
#include "utils/functional.hpp"
#include <boost/ref.hpp>
#include <boost/cstdint.hpp>
#include <boost/version.hpp>
#include "log.hpp"
#include "network_asio.hpp"
#include "serialization/parser.hpp"

static lg::log_domain log_network("network");
#define DBG_NW LOG_STREAM(debug, log_network)
#define LOG_NW LOG_STREAM(info, log_network)
#define WRN_NW LOG_STREAM(warn, log_network)
#define ERR_NW LOG_STREAM(err, log_network)

namespace network_asio {

using boost::system::system_error;

connection::connection(const std::string& host, const std::string& service)
    : io_service_()
    , resolver_(io_service_)
    , socket_(io_service_)
    , done_(false)
    , write_buf_()
    , read_buf_()
    , handshake_response_()
    , payload_size_(0)
    , bytes_to_write_(0)
    , bytes_written_(0)
    , bytes_to_read_(0)
    , bytes_read_(0)
{
    resolver_.async_resolve(
        boost::asio::ip::tcp::resolver::query(host, service),
        std::bind(&connection::handle_resolve, this, _1, _2)
        );
    LOG_NW << "Resolving hostname: " << host << '\n';
}

void connection::handle_resolve(
        const boost::system::error_code& ec,
        resolver::iterator iterator
        )
{
    if(ec)
        throw system_error(ec);

    connect(iterator);
}

void connection::connect(resolver::iterator iterator)
{
    socket_.async_connect(*iterator, std::bind(
        &connection::handle_connect, this, _1, iterator)
        );
    LOG_NW << "Connecting to " << iterator->endpoint().address() << '\n';
}

void connection::handle_connect(
        const boost::system::error_code& ec,
        resolver::iterator iterator
        )
{
    if(ec) {
        WRN_NW << "Failed to connect to " <<
            iterator->endpoint().address() << ": " <<
            ec.message() << '\n';
        socket_.close();
        if(++iterator == resolver::iterator()) {
            ERR_NW << "Tried all IPs. Giving up" << std::endl;
            throw system_error(ec);
        } else
            connect(iterator);
    } else {
        LOG_NW << "Connected to " << iterator->endpoint().address() << '\n';
        handshake();
    }
}

void connection::handshake()
{
    static const boost::uint32_t handshake = 0;
    boost::asio::async_write(socket_,
        boost::asio::buffer(reinterpret_cast<const char*>(&handshake), 4),
        std::bind(&connection::handle_write, this, _1, _2)
        );
    boost::asio::async_read(socket_,
        boost::asio::buffer(&handshake_response_.binary, 4),
        std::bind(&connection::handle_handshake, this, _1)
        );
}

void connection::handle_handshake(
        const boost::system::error_code& ec
        )
{
    if(ec)
        throw system_error(ec);
    done_ = true;
}

void connection::transfer(const config& request, config& response)
{
    io_service_.reset();
    done_ = false;

    std::ostream os(&write_buf_);
    write_gz(os, request);
    bytes_to_write_ = write_buf_.size() + 4;
    bytes_written_ = 0;
    payload_size_ = htonl(bytes_to_write_ - 4);
    boost::asio::streambuf::const_buffers_type gzipped_data = write_buf_.data();
    std::deque<boost::asio::const_buffer> bufs(gzipped_data.begin(), gzipped_data.end());
    bufs.push_front(boost::asio::buffer(reinterpret_cast<const char*>(&payload_size_), 4));
    boost::asio::async_write(socket_, bufs,
        std::bind(&connection::is_write_complete, this, _1, _2),
        std::bind(&connection::handle_write, this, _1, _2)
        );
    boost::asio::async_read(socket_, read_buf_,
        std::bind(&connection::is_read_complete, this, _1, _2),
        std::bind(&connection::handle_read, this, _1, _2, std::ref(response))
        );
}

void connection::cancel()
{
    if(socket_.is_open()) {
        boost::system::error_code ec;
        socket_.cancel(ec);
        if(ec) {
            WRN_NW << "Failed to cancel network operations: " << ec.message() << std::endl;
        }
    }
}

std::size_t connection::is_write_complete(
        const boost::system::error_code& ec,
        std::size_t bytes_transferred
        )
{
    if(ec)
        throw system_error(ec);
    bytes_written_ = bytes_transferred;
#if BOOST_VERSION >= 103700
    return bytes_to_write_ - bytes_transferred;
#else
    return bytes_to_write_ == bytes_transferred;
#endif
}

void connection::handle_write(
    const boost::system::error_code& ec,
    std::size_t bytes_transferred
    )
{
    DBG_NW << "Written " << bytes_transferred << " bytes.\n";
    write_buf_.consume(bytes_transferred);
    if(ec)
        throw system_error(ec);
}

std::size_t connection::is_read_complete(
        const boost::system::error_code& ec,
        std::size_t bytes_transferred
        )
{
    if(ec) {
        throw system_error(ec);
    }
    bytes_read_ = bytes_transferred;
    if(bytes_transferred < 4) {
        return 4;
    } else {
        if(!bytes_to_read_) {
            std::istream is(&read_buf_);
            union { char binary[4]; boost::uint32_t num; } data_size;
            is.read(data_size.binary, 4);
            bytes_to_read_ = ntohl(data_size.num) + 4;
            //Close immediately if we receive an invalid length
            if (bytes_to_read_ < 4)
                bytes_to_read_ = bytes_transferred;
        }
#if BOOST_VERSION >= 103700
        return bytes_to_read_ - bytes_transferred;
#else
        return bytes_to_read_ == bytes_transferred;
#endif
    }
}

void connection::handle_read(
    const boost::system::error_code& ec,
    std::size_t bytes_transferred,
    config& response
    )
{
    DBG_NW << "Read " << bytes_transferred << " bytes.\n";
    bytes_to_read_ = 0;
    bytes_to_write_ = 0;
    done_ = true;
    if(ec && ec != boost::asio::error::eof)
        throw system_error(ec);
    std::istream is(&read_buf_);
    read_gz(response, is);
}

}