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/*
This file is part of cpp-ethereum.
cpp-ethereum 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 3 of the License, or
(at your option) any later version.
cpp-ethereum 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file RLPXHandshake.h
* @author Alex Leverington <nessence@gmail.com>
* @date 2015
*/
#pragma once
#include <memory>
#include <libdevcrypto/Common.h>
#include <libdevcrypto/ECDHE.h>
#include "RLPXSocket.h"
#include "RLPXFrameCoder.h"
#include "Common.h"
namespace ba = boost::asio;
namespace bi = boost::asio::ip;
namespace dev
{
namespace p2p
{
/**
* @brief Setup inbound or outbound connection for communication over RLPXFrameCoder.
* RLPx Spec: https://github.com/ethereum/devp2p/blob/master/rlpx.md#encrypted-handshake
*
* @todo Implement StartSession transition via lambda which is passed to constructor.
*
* Thread Safety
* Distinct Objects: Safe.
* Shared objects: Unsafe.
*/
class RLPXHandshake: public std::enable_shared_from_this<RLPXHandshake>
{
friend class RLPXFrameCoder;
/// Sequential states of handshake
enum State
{
Error = -1,
New,
AckAuth,
WriteHello,
ReadHello,
StartSession
};
public:
/// Setup incoming connection.
RLPXHandshake(Host* _host, std::shared_ptr<RLPXSocket> const& _socket): m_host(_host), m_originated(false), m_socket(_socket), m_idleTimer(m_socket->ref().get_io_service()) { crypto::Nonce::get().ref().copyTo(m_nonce.ref()); }
/// Setup outbound connection.
RLPXHandshake(Host* _host, std::shared_ptr<RLPXSocket> const& _socket, NodeId _remote): m_host(_host), m_remote(_remote), m_originated(true), m_socket(_socket), m_idleTimer(m_socket->ref().get_io_service()) { crypto::Nonce::get().ref().copyTo(m_nonce.ref()); }
~RLPXHandshake() {}
/// Start handshake.
void start() { transition(); }
/// Cancels handshake preventing
void cancel() { m_cancel = true; }
protected:
/// Write Auth message to socket and transitions to AckAuth.
void writeAuth();
/// Reads Auth message from socket and transitions to AckAuth.
void readAuth();
/// Write Ack message to socket and transitions to WriteHello.
void writeAck();
/// Reads Auth message from socket and transitions to WriteHello.
void readAck();
/// Closes connection and ends transitions.
void error();
/// Performs transition for m_nextState.
void transition(boost::system::error_code _ech = boost::system::error_code());
/// Timeout for remote to respond to transition events. Enforced by m_idleTimer and refreshed by transition().
boost::posix_time::milliseconds const c_timeout = boost::posix_time::milliseconds(1800);
State m_nextState = New; ///< Current or expected state of transition.
bool m_cancel = false; ///< Will be set to true if connection was canceled.
Host* m_host; ///< Host which provides m_alias, protocolVersion(), m_clientVersion, caps(), and TCP listenPort().
/// Node id of remote host for socket.
NodeId m_remote; ///< Public address of remote host.
bool m_originated = false; ///< True if connection is outbound.
/// Buffers for encoded and decoded handshake phases
bytes m_auth; ///< Plaintext of egress or ingress Auth message.
bytes m_authCipher; ///< Ciphertext of egress or ingress Auth message.
bytes m_ack; ///< Plaintext of egress or ingress Ack message.
bytes m_ackCipher; ///< Ciphertext of egress or ingress Ack message.
bytes m_handshakeOutBuffer; ///< Frame buffer for egress Hello packet.
bytes m_handshakeInBuffer; ///< Frame buffer for ingress Hello packet.
crypto::ECDHE m_ecdhe; ///< Ephemeral ECDH secret and agreement.
h256 m_nonce; ///< Nonce generated by this host for handshake.
Public m_remoteEphemeral; ///< Remote ephemeral public key.
h256 m_remoteNonce; ///< Nonce generated by remote host for handshake.
/// Used to read and write RLPx encrypted frames for last step of handshake authentication.
/// Passed onto Host which will take ownership.
RLPXFrameCoder* m_io = nullptr;
std::shared_ptr<RLPXSocket> m_socket; ///< Socket.
boost::asio::deadline_timer m_idleTimer; ///< Timer which enforces c_timeout.
};
}
}