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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
* Copyright (c) 2013-2016 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
* ndn-cxx library is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later version.
*
* ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
*
* You should have received copies of the GNU General Public License and GNU Lesser
* General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
* <http://www.gnu.org/licenses/>.
*
* See AUTHORS.md for complete list of ndn-cxx authors and contributors.
*/
#ifndef NDN_TRANSPORT_STREAM_TRANSPORT_IMPL_HPP
#define NDN_TRANSPORT_STREAM_TRANSPORT_IMPL_HPP
#include "transport.hpp"
#include <boost/asio.hpp>
#include <list>
namespace ndn {
/** \brief implementation detail of a Boost.Asio-based stream-oriented transport
* \tparam BaseTransport a subclass of Transport
* \tparam Protocol a Boost.Asio stream-oriented protocol, including boost::asio::ip::tcp
* and boost::asio::local::stream_protocol
*/
template<typename BaseTransport, typename Protocol>
class StreamTransportImpl
{
public:
typedef StreamTransportImpl<BaseTransport,Protocol> Impl;
typedef std::list<Block> BlockSequence;
typedef std::list<BlockSequence> TransmissionQueue;
StreamTransportImpl(BaseTransport& transport, boost::asio::io_service& ioService)
: m_transport(transport)
, m_socket(ioService)
, m_inputBufferSize(0)
, m_isConnecting(false)
, m_connectTimer(ioService)
{
}
void
connect(const typename Protocol::endpoint& endpoint)
{
if (!m_isConnecting) {
m_isConnecting = true;
// Wait at most 4 seconds to connect
/// @todo Decide whether this number should be configurable
m_connectTimer.expires_from_now(boost::posix_time::seconds(4));
m_connectTimer.async_wait(bind(&Impl::connectTimeoutHandler, this, _1));
m_socket.open();
m_socket.async_connect(endpoint, bind(&Impl::connectHandler, this, _1));
}
}
void
close()
{
m_isConnecting = false;
boost::system::error_code error; // to silently ignore all errors
m_connectTimer.cancel(error);
m_socket.cancel(error);
m_socket.close(error);
m_transport.m_isConnected = false;
m_transport.m_isReceiving = false;
m_transmissionQueue.clear();
}
void
pause()
{
if (m_isConnecting)
return;
if (m_transport.m_isReceiving) {
m_transport.m_isReceiving = false;
m_socket.cancel();
}
}
void
resume()
{
if (m_isConnecting)
return;
if (!m_transport.m_isReceiving) {
m_transport.m_isReceiving = true;
m_inputBufferSize = 0;
m_socket.async_receive(boost::asio::buffer(m_inputBuffer, MAX_NDN_PACKET_SIZE), 0,
bind(&Impl::handleAsyncReceive, this, _1, _2));
}
}
void
send(const Block& wire)
{
BlockSequence sequence;
sequence.push_back(wire);
send(std::move(sequence));
}
void
send(const Block& header, const Block& payload)
{
BlockSequence sequence;
sequence.push_back(header);
sequence.push_back(payload);
send(std::move(sequence));
}
protected:
void
connectHandler(const boost::system::error_code& error)
{
m_isConnecting = false;
m_connectTimer.cancel();
if (!error) {
resume();
m_transport.m_isConnected = true;
if (!m_transmissionQueue.empty()) {
boost::asio::async_write(m_socket, *m_transmissionQueue.begin(),
bind(&Impl::handleAsyncWrite, this, _1,
m_transmissionQueue.begin()));
}
}
else {
m_transport.m_isConnected = false;
m_transport.close();
BOOST_THROW_EXCEPTION(Transport::Error(error, "error while connecting to the forwarder"));
}
}
void
connectTimeoutHandler(const boost::system::error_code& error)
{
if (error) // e.g., cancelled timer
return;
m_transport.close();
BOOST_THROW_EXCEPTION(Transport::Error(error, "error while connecting to the forwarder"));
}
void
send(BlockSequence&& sequence)
{
m_transmissionQueue.emplace_back(sequence);
if (m_transport.m_isConnected && m_transmissionQueue.size() == 1) {
boost::asio::async_write(m_socket, *m_transmissionQueue.begin(),
bind(&Impl::handleAsyncWrite, this, _1,
m_transmissionQueue.begin()));
}
// if not connected or there is transmission in progress (m_transmissionQueue.size() > 1),
// next write will be scheduled either in connectHandler or in asyncWriteHandler
}
void
handleAsyncWrite(const boost::system::error_code& error, TransmissionQueue::iterator queueItem)
{
if (error) {
if (error == boost::system::errc::operation_canceled) {
// async receive has been explicitly cancelled (e.g., socket close)
return;
}
m_transport.close();
BOOST_THROW_EXCEPTION(Transport::Error(error, "error while sending data to socket"));
}
if (!m_transport.m_isConnected) {
return; // queue has been already cleared
}
m_transmissionQueue.erase(queueItem);
if (!m_transmissionQueue.empty()) {
boost::asio::async_write(m_socket, *m_transmissionQueue.begin(),
bind(&Impl::handleAsyncWrite, this, _1,
m_transmissionQueue.begin()));
}
}
void
handleAsyncReceive(const boost::system::error_code& error, std::size_t nBytesRecvd)
{
if (error) {
if (error == boost::system::errc::operation_canceled) {
// async receive has been explicitly cancelled (e.g., socket close)
return;
}
m_transport.close();
BOOST_THROW_EXCEPTION(Transport::Error(error, "error while receiving data from socket"));
}
m_inputBufferSize += nBytesRecvd;
// do magic
std::size_t offset = 0;
bool hasProcessedSome = processAllReceived(m_inputBuffer, offset, m_inputBufferSize);
if (!hasProcessedSome && m_inputBufferSize == MAX_NDN_PACKET_SIZE && offset == 0) {
m_transport.close();
BOOST_THROW_EXCEPTION(Transport::Error(boost::system::error_code(),
"input buffer full, but a valid TLV cannot be "
"decoded"));
}
if (offset > 0) {
if (offset != m_inputBufferSize) {
std::copy(m_inputBuffer + offset, m_inputBuffer + m_inputBufferSize, m_inputBuffer);
m_inputBufferSize -= offset;
}
else {
m_inputBufferSize = 0;
}
}
m_socket.async_receive(boost::asio::buffer(m_inputBuffer + m_inputBufferSize,
MAX_NDN_PACKET_SIZE - m_inputBufferSize), 0,
bind(&Impl::handleAsyncReceive, this, _1, _2));
}
bool
processAllReceived(uint8_t* buffer, size_t& offset, size_t nBytesAvailable)
{
while (offset < nBytesAvailable) {
bool isOk = false;
Block element;
std::tie(isOk, element) = Block::fromBuffer(buffer + offset, nBytesAvailable - offset);
if (!isOk)
return false;
m_transport.receive(element);
offset += element.size();
}
return true;
}
protected:
BaseTransport& m_transport;
typename Protocol::socket m_socket;
uint8_t m_inputBuffer[MAX_NDN_PACKET_SIZE];
size_t m_inputBufferSize;
TransmissionQueue m_transmissionQueue;
bool m_isConnecting;
boost::asio::deadline_timer m_connectTimer;
};
} // namespace ndn
#endif // NDN_TRANSPORT_STREAM_TRANSPORT_IMPL_HPP