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10 years ago
6 changed files with 262 additions and 136 deletions
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/*
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This file is part of cpp-ethereum. |
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cpp-ethereum is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation, either version 3 of the License, or |
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(at your option) any later version. |
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cpp-ethereum is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
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*/ |
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/** @file UDP.cpp
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* @author Alex Leverington <nessence@gmail.com> |
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* @date 2014 |
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*/ |
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/*
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This file is part of cpp-ethereum. |
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cpp-ethereum is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation, either version 3 of the License, or |
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(at your option) any later version. |
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|
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cpp-ethereum is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
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*/ |
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/** @file UDP.h
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* @author Alex Leverington <nessence@gmail.com> |
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* @date 2014 |
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*/ |
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#pragma once |
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#include <memory> |
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#include <vector> |
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#include <deque> |
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#include <array> |
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#include <libdevcore/Guards.h> |
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#include "Common.h" |
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namespace ba = boost::asio; |
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namespace bi = ba::ip; |
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namespace dev |
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{ |
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namespace p2p |
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{ |
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struct UDPDatagram |
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{ |
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bi::udp::endpoint to; |
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bytes data; |
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}; |
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struct UDPSocketFace |
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{ |
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virtual void send(UDPDatagram const& _msg) = 0; |
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virtual void disconnect() = 0; |
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}; |
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struct UDPSocketEvents |
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{ |
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virtual void onDisconnected(UDPSocketFace*) {}; |
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virtual void onReceived(UDPSocketFace*, bi::udp::endpoint const& _from, bytesConstRef _packetData) = 0; |
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}; |
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/**
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* @brief UDP Interface |
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* Handler must implement UDPSocketEvents. S is maximum data size (bytes) of UDP datagram. |
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*/ |
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template <typename Handler, unsigned S> |
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class UDPSocket: UDPSocketFace, public std::enable_shared_from_this<UDPSocket<Handler, S>> |
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{ |
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public: |
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static constexpr unsigned datagramSize = S; |
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static_assert(datagramSize < 65507, "UDP datagrams cannot be larger than 65507 bytes"); |
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/// Construct open socket to endpoint.
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UDPSocket(ba::io_service& _io, Handler& _host, unsigned _port): m_host(_host), m_socket(_io, bi::udp::endpoint(bi::udp::v4(), _port)) {}; |
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virtual ~UDPSocket() { disconnect(); } |
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void connect() |
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{ |
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bool no = false; |
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if (!m_started.compare_exchange_strong(no, true)) |
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return; |
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m_closed = false; |
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doRead(); |
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} |
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void send(UDPDatagram const& _datagram) |
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{ |
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if (!m_started) |
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return; |
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Guard l(x_sendQ); |
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sendQ.push_back(_datagram); |
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if (sendQ.size() == 1 && !m_closed) |
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doWrite(); |
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} |
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void disconnect() { disconnectWithError(boost::asio::error::connection_reset); } |
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protected: |
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void doRead() |
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{ |
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auto self(UDPSocket<Handler, S>::shared_from_this()); |
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m_socket.async_receive_from(boost::asio::buffer(recvData), recvEndpoint, [this, self](boost::system::error_code _ec, size_t _len) |
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{ |
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if (_ec) |
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return disconnectWithError(_ec); |
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assert(_len); |
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m_host.onReceived(this, recvEndpoint, bytesConstRef(recvData.data(), _len)); |
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if (!m_closed) |
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doRead(); |
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}); |
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} |
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void doWrite() |
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{ |
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const UDPDatagram& datagram = sendQ[0]; |
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auto self(UDPSocket<Handler, S>::shared_from_this()); |
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m_socket.async_send_to(boost::asio::buffer(datagram.data), datagram.to, [this, self](boost::system::error_code _ec, std::size_t) |
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{ |
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if (_ec) |
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return disconnectWithError(_ec); |
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else |
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{ |
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Guard l(x_sendQ); |
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sendQ.pop_front(); |
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if (sendQ.empty()) |
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return; |
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} |
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doWrite(); |
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}); |
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} |
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void disconnectWithError(boost::system::error_code _ec) |
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{ |
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// If !started and already stopped, shutdown has already occured. (EOF or Operation canceled)
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if (!m_started && m_closed) |
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return; |
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assert(_ec); |
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{ |
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// disconnect-operation following prior non-zero errors are ignored
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Guard l(x_socketError); |
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if (socketError != boost::system::error_code()) |
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return; |
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socketError = _ec; |
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} |
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// TODO: (if non-zero error) schedule high-priority writes
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// prevent concurrent disconnect
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bool yes = true; |
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if (!m_started.compare_exchange_strong(yes, false)) |
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return; |
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// set m_closed to true to prevent undeliverable egress messages
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bool wasClosed = m_closed; |
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m_closed = true; |
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// close sockets
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boost::system::error_code ec; |
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m_socket.shutdown(bi::udp::socket::shutdown_both, ec); |
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m_socket.close(); |
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// socket never started if it never left stopped-state (pre-handshake)
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if (wasClosed) |
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return; |
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m_host.onDisconnected(this); |
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} |
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std::atomic<bool> m_closed; ///< Set when connection is stopping or stopped. Handshake cannot occur unless m_closed is true.
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std::atomic<bool> m_started; ///< Atomically ensure connection is started once. Start cannot occur unless m_started is false. Managed by start and disconnectWithError.
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Handler& m_host; ///< Interface which owns this socket.
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Mutex x_sendQ; |
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std::deque<UDPDatagram> sendQ; |
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std::array<byte, datagramSize> recvData; ///< Buffer for ingress datagrams.
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bi::udp::endpoint recvEndpoint; ///< Endpoint data was received from.
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bi::udp::socket m_socket; |
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Mutex x_socketError; ///< Mutex for error which can occur from host or IO thread.
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boost::system::error_code socketError; ///< Set when shut down due to error.
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}; |
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} |
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} |
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