I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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/*
* Copyright (c) 2013-2023, 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 TRANSPORT_SESSION_H__
#define TRANSPORT_SESSION_H__
#include <inttypes.h>
#include <iostream>
#include <memory>
#include <vector>
#include <mutex>
#include "Identity.h"
#include "Crypto.h"
#include "RouterInfo.h"
#include "I2NPProtocol.h"
#include "Timestamp.h"
namespace i2p
{
namespace transport
{
const size_t IPV4_HEADER_SIZE = 20;
const size_t IPV6_HEADER_SIZE = 40;
const size_t UDP_HEADER_SIZE = 8;
class SignedData
{
public:
SignedData () {}
SignedData (const SignedData& other)
{
m_Stream << other.m_Stream.rdbuf ();
}
void Reset ()
{
m_Stream.str("");
}
void Insert (const uint8_t * buf, size_t len)
{
m_Stream.write ((char *)buf, len);
}
template<typename T>
void Insert (T t)
{
m_Stream.write ((char *)&t, sizeof (T));
}
bool Verify (std::shared_ptr<const i2p::data::IdentityEx> ident, const uint8_t * signature) const
{
return ident->Verify ((const uint8_t *)m_Stream.str ().c_str (), m_Stream.str ().size (), signature);
}
void Sign (const i2p::data::PrivateKeys& keys, uint8_t * signature) const
{
keys.Sign ((const uint8_t *)m_Stream.str ().c_str (), m_Stream.str ().size (), signature);
}
private:
std::stringstream m_Stream;
};
const int64_t TRANSPORT_SESSION_SLOWNESS_THRESHOLD = 500; // in milliseconds
const int64_t TRANSPORT_SESSION_MAX_HANDSHAKE_INTERVAL = 10000; // in milliseconds
const uint64_t TRANSPORT_SESSION_BANDWIDTH_UPDATE_MIN_INTERVAL = 5; // in seconds
class TransportSession
{
public:
TransportSession (std::shared_ptr<const i2p::data::RouterInfo> router, int terminationTimeout):
m_IsOutgoing (router), m_TerminationTimeout (terminationTimeout), m_HandshakeInterval (0),
m_SendQueueSize (0), m_NumSentBytes (0), m_NumReceivedBytes (0),
m_LastBandWidthUpdateNumSentBytes (0), m_LastBandWidthUpdateNumReceivedBytes (0),
m_LastActivityTimestamp (i2p::util::GetSecondsSinceEpoch ()),
m_LastBandwidthUpdateTimestamp (m_LastActivityTimestamp), m_InBandwidth (0), m_OutBandwidth (0)
{
if (router)
m_RemoteIdentity = router->GetRouterIdentity ();
m_CreationTime = m_LastActivityTimestamp;
}
virtual ~TransportSession () {};
virtual void Done () = 0;
std::string GetIdentHashBase64() const { return m_RemoteIdentity ? m_RemoteIdentity->GetIdentHash().ToBase64() : ""; }
std::shared_ptr<const i2p::data::IdentityEx> GetRemoteIdentity ()
{
std::lock_guard<std::mutex> l(m_RemoteIdentityMutex);
return m_RemoteIdentity;
}
void SetRemoteIdentity (std::shared_ptr<const i2p::data::IdentityEx> ident)
{
std::lock_guard<std::mutex> l(m_RemoteIdentityMutex);
m_RemoteIdentity = ident;
}
size_t GetNumSentBytes () const { return m_NumSentBytes; };
void UpdateNumSentBytes (size_t len)
{
m_LastActivityTimestamp = i2p::util::GetSecondsSinceEpoch ();
m_NumSentBytes += len;
UpdateBandwidth ();
}
size_t GetNumReceivedBytes () const { return m_NumReceivedBytes; };
void UpdateNumReceivedBytes (size_t len)
{
m_LastActivityTimestamp = i2p::util::GetSecondsSinceEpoch ();
m_NumReceivedBytes += len;
UpdateBandwidth ();
}
size_t GetSendQueueSize () const { return m_SendQueueSize; };
void SetSendQueueSize (size_t s) { m_SendQueueSize = s; };
bool IsOutgoing () const { return m_IsOutgoing; };
bool IsSlow () const { return m_HandshakeInterval > TRANSPORT_SESSION_SLOWNESS_THRESHOLD &&
m_HandshakeInterval < TRANSPORT_SESSION_MAX_HANDSHAKE_INTERVAL; };
bool IsBandwidthExceeded (bool isHighBandwidth) const
{
auto limit = isHighBandwidth ? i2p::data::HIGH_BANDWIDTH_LIMIT*1024 : i2p::data::LOW_BANDWIDTH_LIMIT*1024; // convert to bytes
return std::max (m_InBandwidth, m_OutBandwidth) > limit;
}
int GetTerminationTimeout () const { return m_TerminationTimeout; };
void SetTerminationTimeout (int terminationTimeout) { m_TerminationTimeout = terminationTimeout; };
bool IsTerminationTimeoutExpired (uint64_t ts) const
{
return ts >= m_LastActivityTimestamp + GetTerminationTimeout () ||
ts + GetTerminationTimeout () < m_LastActivityTimestamp;
};
uint32_t GetCreationTime () const { return m_CreationTime; };
void SetCreationTime (uint32_t ts) { m_CreationTime = ts; }; // for introducers
uint64_t GetLastActivityTimestamp () const { return m_LastActivityTimestamp; };
void SetLastActivityTimestamp (uint64_t ts) { m_LastActivityTimestamp = ts; };
virtual uint32_t GetRelayTag () const { return 0; };
virtual void SendLocalRouterInfo (bool update = false) { SendI2NPMessages ({ CreateDatabaseStoreMsg () }); };
virtual void SendI2NPMessages (const std::vector<std::shared_ptr<I2NPMessage> >& msgs) = 0;
virtual bool IsEstablished () const = 0;
private:
void UpdateBandwidth ()
{
uint64_t interval = m_LastActivityTimestamp - m_LastBandwidthUpdateTimestamp;
if (interval > TRANSPORT_SESSION_BANDWIDTH_UPDATE_MIN_INTERVAL)
{
m_OutBandwidth = (m_NumSentBytes - m_LastBandWidthUpdateNumSentBytes)/interval;
m_LastBandWidthUpdateNumSentBytes = m_NumSentBytes;
m_InBandwidth = (m_NumReceivedBytes - m_LastBandWidthUpdateNumReceivedBytes)/interval;
m_LastBandWidthUpdateNumReceivedBytes = m_NumReceivedBytes;
m_LastBandwidthUpdateTimestamp = m_LastActivityTimestamp;
}
}
protected:
std::shared_ptr<const i2p::data::IdentityEx> m_RemoteIdentity;
mutable std::mutex m_RemoteIdentityMutex;
bool m_IsOutgoing;
int m_TerminationTimeout;
uint32_t m_CreationTime; // seconds since epoch
int64_t m_HandshakeInterval; // in milliseconds between SessionRequest->SessionCreated or SessionCreated->SessionConfirmed
private:
size_t m_SendQueueSize, m_NumSentBytes, m_NumReceivedBytes,
m_LastBandWidthUpdateNumSentBytes, m_LastBandWidthUpdateNumReceivedBytes;
uint64_t m_LastActivityTimestamp, m_LastBandwidthUpdateTimestamp;
uint32_t m_InBandwidth, m_OutBandwidth;
};
// SOCKS5 proxy
const uint8_t SOCKS5_VER = 0x05;
const uint8_t SOCKS5_CMD_CONNECT = 0x01;
const uint8_t SOCKS5_CMD_UDP_ASSOCIATE = 0x03;
const uint8_t SOCKS5_ATYP_IPV4 = 0x01;
const uint8_t SOCKS5_ATYP_IPV6 = 0x04;
const size_t SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE = 10;
const size_t SOCKS5_UDP_IPV6_REQUEST_HEADER_SIZE = 22;
}
}
#endif