I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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/*
* Copyright (c) 2013-2020, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*
*/
#ifndef NTCP2_H__
#define NTCP2_H__
#include <inttypes.h>
#include <memory>
#include <thread>
#include <list>
#include <map>
#include <array>
#include <openssl/bn.h>
#include <openssl/evp.h>
#include <boost/asio.hpp>
#include "Crypto.h"
#include "util.h"
#include "RouterInfo.h"
#include "TransportSession.h"
namespace i2p
{
namespace transport
{
const size_t NTCP2_UNENCRYPTED_FRAME_MAX_SIZE = 65519;
const int NTCP2_MAX_PADDING_RATIO = 6; // in %
const int NTCP2_CONNECT_TIMEOUT = 5; // 5 seconds
const int NTCP2_ESTABLISH_TIMEOUT = 10; // 10 seconds
const int NTCP2_TERMINATION_TIMEOUT = 120; // 2 minutes
const int NTCP2_TERMINATION_CHECK_TIMEOUT = 30; // 30 seconds
const int NTCP2_CLOCK_SKEW = 60; // in seconds
const int NTCP2_MAX_OUTGOING_QUEUE_SIZE = 500; // how many messages we can queue up
enum NTCP2BlockType
{
eNTCP2BlkDateTime = 0,
eNTCP2BlkOptions, // 1
eNTCP2BlkRouterInfo, // 2
eNTCP2BlkI2NPMessage, // 3
eNTCP2BlkTermination, // 4
eNTCP2BlkPadding = 254
};
enum NTCP2TerminationReason
{
eNTCP2NormalClose = 0,
eNTCP2TerminationReceived, // 1
eNTCP2IdleTimeout, // 2
eNTCP2RouterShutdown, // 3
eNTCP2DataPhaseAEADFailure, // 4
eNTCP2IncompatibleOptions, // 5
eNTCP2IncompatibleSignatureType, // 6
eNTCP2ClockSkew, // 7
eNTCP2PaddingViolation, // 8
eNTCP2AEADFramingError, // 9
eNTCP2PayloadFormatError, // 10
eNTCP2Message1Error, // 11
eNTCP2Message2Error, // 12
eNTCP2Message3Error, // 13
eNTCP2IntraFrameReadTimeout, // 14
eNTCP2RouterInfoSignatureVerificationFail, // 15
eNTCP2IncorrectSParameter, // 16
eNTCP2Banned, // 17
};
// RouterInfo flags
const uint8_t NTCP2_ROUTER_INFO_FLAG_REQUEST_FLOOD = 0x01;
struct NTCP2Establisher
{
NTCP2Establisher ();
~NTCP2Establisher ();
const uint8_t * GetPub () const { return m_EphemeralKeys.GetPublicKey (); };
const uint8_t * GetRemotePub () const { return m_RemoteEphemeralPublicKey; }; // Y for Alice and X for Bob
uint8_t * GetRemotePub () { return m_RemoteEphemeralPublicKey; }; // to set
const uint8_t * GetK () const { return m_CK + 32; };
const uint8_t * GetCK () const { return m_CK; };
const uint8_t * GetH () const { return m_H; };
void KDF1Alice ();
void KDF1Bob ();
void KDF2Alice ();
void KDF2Bob ();
void KDF3Alice (); // for SessionConfirmed part 2
void KDF3Bob ();
void MixKey (const uint8_t * inputKeyMaterial);
void MixHash (const uint8_t * buf, size_t len);
void KeyDerivationFunction1 (const uint8_t * pub, i2p::crypto::X25519Keys& priv, const uint8_t * rs, const uint8_t * epub); // for SessionRequest, (pub, priv) for DH
void KeyDerivationFunction2 (const uint8_t * sessionRequest, size_t sessionRequestLen, const uint8_t * epub); // for SessionCreate
void CreateEphemeralKey ();
void CreateSessionRequestMessage ();
void CreateSessionCreatedMessage ();
void CreateSessionConfirmedMessagePart1 (const uint8_t * nonce);
void CreateSessionConfirmedMessagePart2 (const uint8_t * nonce);
bool ProcessSessionRequestMessage (uint16_t& paddingLen);
bool ProcessSessionCreatedMessage (uint16_t& paddingLen);
bool ProcessSessionConfirmedMessagePart1 (const uint8_t * nonce);
bool ProcessSessionConfirmedMessagePart2 (const uint8_t * nonce, uint8_t * m3p2Buf);
i2p::crypto::X25519Keys m_EphemeralKeys;
uint8_t m_RemoteEphemeralPublicKey[32]; // x25519
uint8_t m_RemoteStaticKey[32], m_IV[16], m_H[32] /*h*/, m_CK[64] /* [ck, k]*/;
i2p::data::IdentHash m_RemoteIdentHash;
uint16_t m3p2Len;
uint8_t * m_SessionRequestBuffer, * m_SessionCreatedBuffer, * m_SessionConfirmedBuffer;
size_t m_SessionRequestBufferLen, m_SessionCreatedBufferLen;
};
class NTCP2Server;
class NTCP2Session: public TransportSession, public std::enable_shared_from_this<NTCP2Session>
{
public:
NTCP2Session (NTCP2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter = nullptr);
~NTCP2Session ();
void Terminate ();
void TerminateByTimeout ();
void Done ();
void Close () { m_Socket.close (); }; // for accept
boost::asio::ip::tcp::socket& GetSocket () { return m_Socket; };
bool IsEstablished () const { return m_IsEstablished; };
bool IsTerminated () const { return m_IsTerminated; };
void ClientLogin (); // Alice
void ServerLogin (); // Bob
void SendLocalRouterInfo (); // after handshake
void SendI2NPMessages (const std::vector<std::shared_ptr<I2NPMessage> >& msgs);
private:
void Established ();
void CreateNonce (uint64_t seqn, uint8_t * nonce);
void KeyDerivationFunctionDataPhase ();
void SetSipKeys (const uint8_t * sendSipKey, const uint8_t * receiveSipKey);
// establish
void SendSessionRequest ();
void SendSessionCreated ();
void SendSessionConfirmed ();
void HandleSessionRequestSent (const boost::system::error_code& ecode, std::size_t bytes_transferred);
void HandleSessionRequestReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred);
void HandleSessionRequestPaddingReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred);
void HandleSessionCreatedSent (const boost::system::error_code& ecode, std::size_t bytes_transferred);
void HandleSessionCreatedReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred);
void HandleSessionCreatedPaddingReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred);
void HandleSessionConfirmedSent (const boost::system::error_code& ecode, std::size_t bytes_transferred);
void HandleSessionConfirmedReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred);
// data
void ReceiveLength ();
void HandleReceivedLength (const boost::system::error_code& ecode, std::size_t bytes_transferred);
void Receive ();
void HandleReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred);
void ProcessNextFrame (const uint8_t * frame, size_t len);
void SetNextSentFrameLength (size_t frameLen, uint8_t * lengthBuf);
void SendI2NPMsgs (std::vector<std::shared_ptr<I2NPMessage> >& msgs);
void HandleI2NPMsgsSent (const boost::system::error_code& ecode, std::size_t bytes_transferred, std::vector<std::shared_ptr<I2NPMessage> > msgs);
void EncryptAndSendNextBuffer (size_t payloadLen);
void HandleNextFrameSent (const boost::system::error_code& ecode, std::size_t bytes_transferred);
size_t CreatePaddingBlock (size_t msgLen, uint8_t * buf, size_t len);
void SendQueue ();
void SendRouterInfo ();
void SendTermination (NTCP2TerminationReason reason);
void SendTerminationAndTerminate (NTCP2TerminationReason reason);
void PostI2NPMessages (std::vector<std::shared_ptr<I2NPMessage> > msgs);
private:
NTCP2Server& m_Server;
boost::asio::ip::tcp::socket m_Socket;
bool m_IsEstablished, m_IsTerminated;
std::unique_ptr<NTCP2Establisher> m_Establisher;
// data phase
uint8_t m_Kab[32], m_Kba[32], m_Sipkeysab[32], m_Sipkeysba[32];
const uint8_t * m_SendKey, * m_ReceiveKey;
#if OPENSSL_SIPHASH
EVP_PKEY * m_SendSipKey, * m_ReceiveSipKey;
EVP_MD_CTX * m_SendMDCtx, * m_ReceiveMDCtx;
#else
const uint8_t * m_SendSipKey, * m_ReceiveSipKey;
#endif
uint16_t m_NextReceivedLen;
uint8_t * m_NextReceivedBuffer, * m_NextSendBuffer;
union
{
uint8_t buf[8];
uint16_t key;
} m_ReceiveIV, m_SendIV;
uint64_t m_ReceiveSequenceNumber, m_SendSequenceNumber;
i2p::I2NPMessagesHandler m_Handler;
bool m_IsSending;
std::list<std::shared_ptr<I2NPMessage> > m_SendQueue;
};
class NTCP2Server: private i2p::util::RunnableServiceWithWork
{
public:
enum RemoteAddressType
{
eIP4Address,
eIP6Address,
eHostname
};
enum ProxyType
{
eNoProxy,
eSocksProxy,
eHTTPProxy
};
NTCP2Server ();
~NTCP2Server ();
void Start ();
void Stop ();
boost::asio::io_service& GetService () { return GetIOService (); };
bool AddNTCP2Session (std::shared_ptr<NTCP2Session> session, bool incoming = false);
void RemoveNTCP2Session (std::shared_ptr<NTCP2Session> session);
std::shared_ptr<NTCP2Session> FindNTCP2Session (const i2p::data::IdentHash& ident);
void ConnectWithProxy (const std::string& addr, uint16_t port, RemoteAddressType addrtype, std::shared_ptr<NTCP2Session> conn);
void Connect(const boost::asio::ip::address & address, uint16_t port, std::shared_ptr<NTCP2Session> conn);
void AfterSocksHandshake(std::shared_ptr<NTCP2Session> conn, std::shared_ptr<boost::asio::deadline_timer> timer, const std::string & host, uint16_t port, RemoteAddressType addrtype);
bool UsingProxy() const { return m_ProxyType != eNoProxy; };
void UseProxy(ProxyType proxy, const std::string & address, uint16_t port);
private:
void HandleAccept (std::shared_ptr<NTCP2Session> conn, const boost::system::error_code& error);
void HandleAcceptV6 (std::shared_ptr<NTCP2Session> conn, const boost::system::error_code& error);
void HandleConnect (const boost::system::error_code& ecode, std::shared_ptr<NTCP2Session> conn, std::shared_ptr<boost::asio::deadline_timer> timer);
void HandleProxyConnect(const boost::system::error_code& ecode, std::shared_ptr<NTCP2Session> conn, std::shared_ptr<boost::asio::deadline_timer> timer, const std::string & host, uint16_t port, RemoteAddressType adddrtype);
// timer
void ScheduleTermination ();
void HandleTerminationTimer (const boost::system::error_code& ecode);
private:
boost::asio::deadline_timer m_TerminationTimer;
std::unique_ptr<boost::asio::ip::tcp::acceptor> m_NTCP2Acceptor, m_NTCP2V6Acceptor;
std::map<i2p::data::IdentHash, std::shared_ptr<NTCP2Session> > m_NTCP2Sessions;
std::list<std::shared_ptr<NTCP2Session> > m_PendingIncomingSessions;
ProxyType m_ProxyType;
std::string m_ProxyAddress;
uint16_t m_ProxyPort;
boost::asio::ip::tcp::resolver m_Resolver;
boost::asio::ip::tcp::endpoint * m_ProxyEndpoint;
public:
// for HTTP/I2PControl
const decltype(m_NTCP2Sessions)& GetNTCP2Sessions () const { return m_NTCP2Sessions; };
};
}
}
#endif