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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 RLPXFrameCoder.h
* @author Alex Leverington <nessence@gmail.com>
* @date 2015
*/
#pragma once
#include <memory>
#include <libdevcore/Guards.h>
#include <libdevcrypto/ECDHE.h>
#include <libdevcrypto/CryptoPP.h>
#include "Common.h"
namespace dev
{
namespace p2p
{
struct RLPXFrameDecryptFailed: virtual dev::Exception {};
/**
* @brief Encapsulation of Frame
* @todo coder integration; padding derived from coder
*/
struct RLPXFrameInfo
{
RLPXFrameInfo() = default;
/// Constructor. frame-size || protocol-type, [sequence-id[, total-packet-size]]
RLPXFrameInfo(bytesConstRef _frameHeader);
uint32_t const length; ///< Size of frame (excludes padding). Max: 2**24
uint8_t const padding; ///< Length of padding which follows @length.
bytes const data; ///< Bytes of Header.
RLP const header; ///< Header RLP.
uint16_t const protocolId; ///< Protocol ID as negotiated by handshake.
bool const multiFrame; ///< If this frame is part of a sequence
uint16_t const sequenceId; ///< Sequence ID of frame
uint32_t const totalLength; ///< Set to total length of packet in first frame of multiframe packet
};
class RLPXHandshake;
/**
* @brief Encoder/decoder transport for RLPx connection established by RLPXHandshake.
*
* @todo rename to RLPXTranscoder
* @todo Remove 'Frame' nomenclature and expect caller to provide RLPXFrame
* @todo Remove handshake as friend, remove handshake-based constructor
*
* Thread Safety
* Distinct Objects: Unsafe.
* Shared objects: Unsafe.
*/
class RLPXFrameCoder
{
friend class RLPXFrameIOMux;
friend class Session;
public:
/// Construct; requires instance of RLPXHandshake which has encrypted ECDH key exchange (first two phases of handshake).
RLPXFrameCoder(RLPXHandshake const& _init);
/// Construct with external key material.
RLPXFrameCoder(bool _originated, h512 const& _remoteEphemeral, h256 const& _remoteNonce, crypto::ECDHE const& _ephemeral, h256 const& _nonce, bytesConstRef _ackCipher, bytesConstRef _authCipher);
~RLPXFrameCoder() {}
/// Establish shared secrets and setup AES and MAC states.
void setup(bool _originated, h512 const& _remoteEphemeral, h256 const& _remoteNonce, crypto::ECDHE const& _ephemeral, h256 const& _nonce, bytesConstRef _ackCipher, bytesConstRef _authCipher);
/// Write single-frame payload of packet(s).
void writeFrame(uint16_t _protocolType, bytesConstRef _payload, bytes& o_bytes);
/// Write continuation frame of segmented payload.
void writeFrame(uint16_t _protocolType, uint16_t _seqId, bytesConstRef _payload, bytes& o_bytes);
/// Write first frame of segmented or sequence-tagged payload.
void writeFrame(uint16_t _protocolType, uint16_t _seqId, uint32_t _totalSize, bytesConstRef _payload, bytes& o_bytes);
/// Legacy. Encrypt _packet as ill-defined legacy RLPx frame.
void writeSingleFramePacket(bytesConstRef _packet, bytes& o_bytes);
/// Authenticate and decrypt header in-place.
bool authAndDecryptHeader(bytesRef io_cipherWithMac);
/// Authenticate and decrypt frame in-place.
bool authAndDecryptFrame(bytesRef io_cipherWithMac);
/// Return first 16 bytes of current digest from egress mac.
h128 egressDigest();
/// Return first 16 bytes of current digest from ingress mac.
h128 ingressDigest();
protected:
void writeFrame(RLPStream const& _header, bytesConstRef _payload, bytes& o_bytes);
/// Update state of egress MAC with frame header.
void updateEgressMACWithHeader(bytesConstRef _headerCipher);
/// Update state of egress MAC with frame.
void updateEgressMACWithFrame(bytesConstRef _cipher);
/// Update state of ingress MAC with frame header.
void updateIngressMACWithHeader(bytesConstRef _headerCipher);
/// Update state of ingress MAC with frame.
void updateIngressMACWithFrame(bytesConstRef _cipher);
private:
/// Update state of _mac.
void updateMAC(CryptoPP::SHA3_256& _mac, bytesConstRef _seed = bytesConstRef());
CryptoPP::SecByteBlock m_frameEncKey; ///< Key for m_frameEnc
CryptoPP::CTR_Mode<CryptoPP::AES>::Encryption m_frameEnc; ///< Encoder for egress plaintext.
CryptoPP::SecByteBlock m_frameDecKey; ///< Key for m_frameDec
CryptoPP::CTR_Mode<CryptoPP::AES>::Encryption m_frameDec; ///< Decoder for egress plaintext.
CryptoPP::SecByteBlock m_macEncKey; /// Key for m_macEnd
CryptoPP::ECB_Mode<CryptoPP::AES>::Encryption m_macEnc; /// One-way coder used by updateMAC for ingress and egress MAC updates.
Mutex x_macEnc; /// Mutex
CryptoPP::SHA3_256 m_egressMac; ///< State of MAC for egress ciphertext.
CryptoPP::SHA3_256 m_ingressMac; ///< State of MAC for ingress ciphertext.
};
}
}