I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <fstream>
#include <algorithm>
#include <cryptopp/dh.h>
#include <cryptopp/gzip.h>
#include "util.h"
#include "Log.h"
#include "RouterInfo.h"
#include "RouterContext.h"
#include "Tunnel.h"
#include "Timestamp.h"
#include "CryptoConst.h"
#include "Garlic.h"
#include "NetDb.h"
#include "Streaming.h"
namespace i2p
{
namespace stream
{
Stream::Stream (boost::asio::io_service& service, StreamingDestination * local,
const i2p::data::LeaseSet& remote): m_Service (service), m_SendStreamID (0),
m_SequenceNumber (0), m_LastReceivedSequenceNumber (-1), m_IsOpen (false),
m_LeaseSetUpdated (true), m_LocalDestination (local),
m_RemoteLeaseSet (&remote), m_ReceiveTimer (m_Service), m_ResendTimer (m_Service)
{
m_RecvStreamID = i2p::context.GetRandomNumberGenerator ().GenerateWord32 ();
UpdateCurrentRemoteLease ();
}
Stream::Stream (boost::asio::io_service& service, StreamingDestination * local):
m_Service (service), m_SendStreamID (0), m_SequenceNumber (0), m_LastReceivedSequenceNumber (-1),
m_IsOpen (false), m_LeaseSetUpdated (true), m_LocalDestination (local),
m_RemoteLeaseSet (nullptr), m_ReceiveTimer (m_Service), m_ResendTimer (m_Service)
{
m_RecvStreamID = i2p::context.GetRandomNumberGenerator ().GenerateWord32 ();
}
Stream::~Stream ()
{
m_ReceiveTimer.cancel ();
m_ResendTimer.cancel ();
while (!m_ReceiveQueue.empty ())
{
auto packet = m_ReceiveQueue.front ();
m_ReceiveQueue.pop ();
delete packet;
}
for (auto it: m_SavedPackets)
delete it;
for (auto it: m_SentPackets)
delete it;
}
void Stream::HandleNextPacket (Packet * packet)
{
if (!m_SendStreamID)
m_SendStreamID = packet->GetReceiveStreamID ();
if (!packet->IsNoAck ()) // ack received
ProcessAck (packet);
int32_t receivedSeqn = packet->GetSeqn ();
bool isSyn = packet->IsSYN ();
if (!receivedSeqn && !isSyn)
{
// plain ack
LogPrint ("Plain ACK received");
delete packet;
return;
}
LogPrint ("Received seqn=", receivedSeqn);
if (isSyn || receivedSeqn == m_LastReceivedSequenceNumber + 1)
{
// we have received next in sequence message
ProcessPacket (packet);
// we should also try stored messages if any
for (auto it = m_SavedPackets.begin (); it != m_SavedPackets.end ();)
{
if ((*it)->GetSeqn () == (uint32_t)(m_LastReceivedSequenceNumber + 1))
{
Packet * savedPacket = *it;
m_SavedPackets.erase (it++);
ProcessPacket (savedPacket);
}
else
break;
}
// send ack for last message
if (m_IsOpen)
SendQuickAck ();
else if (isSyn)
// we have to send SYN back to incoming connection
Send (nullptr, 0, 0); // also sets m_IsOpen
}
else
{
if (receivedSeqn <= m_LastReceivedSequenceNumber)
{
// we have received duplicate. Most likely our outbound tunnel is dead
LogPrint ("Duplicate message ", receivedSeqn, " received");
UpdateCurrentRemoteLease (); // pick another lease
SendQuickAck (); // resend ack for previous message again
delete packet; // packet dropped
}
else
{
LogPrint ("Missing messages from ", m_LastReceivedSequenceNumber + 1, " to ", receivedSeqn - 1);
// save message and wait for missing message again
SavePacket (packet);
}
}
}
void Stream::SavePacket (Packet * packet)
{
m_SavedPackets.insert (packet);
}
void Stream::ProcessPacket (Packet * packet)
{
// process flags
uint32_t receivedSeqn = packet->GetSeqn ();
uint16_t flags = packet->GetFlags ();
LogPrint ("Process seqn=", receivedSeqn, ", flags=", flags);
const uint8_t * optionData = packet->GetOptionData ();
if (flags & PACKET_FLAG_SYNCHRONIZE)
{
LogPrint ("Synchronize");
}
if (flags & PACKET_FLAG_DELAY_REQUESTED)
{
optionData += 2;
}
if (flags & PACKET_FLAG_FROM_INCLUDED)
{
optionData += m_RemoteIdentity.FromBuffer (optionData, i2p::data::DEFAULT_IDENTITY_SIZE);
LogPrint ("From identity ", m_RemoteIdentity.Hash ().ToBase64 ());
if (!m_RemoteLeaseSet)
LogPrint ("Incoming stream from ", m_RemoteIdentity.Hash ().ToBase64 ());
}
if (flags & PACKET_FLAG_MAX_PACKET_SIZE_INCLUDED)
{
uint16_t maxPacketSize = be16toh (*(uint16_t *)optionData);
LogPrint ("Max packet size ", maxPacketSize);
optionData += 2;
}
if (flags & PACKET_FLAG_SIGNATURE_INCLUDED)
{
LogPrint ("Signature");
optionData += 40;
}
packet->offset = packet->GetPayload () - packet->buf;
if (packet->GetLength () > 0)
{
m_ReceiveQueue.push (packet);
m_ReceiveTimer.cancel ();
}
else
delete packet;
m_LastReceivedSequenceNumber = receivedSeqn;
if (flags & PACKET_FLAG_CLOSE)
{
LogPrint ("Closed");
SendQuickAck (); // send ack for close explicitly?
m_IsOpen = false;
m_ReceiveTimer.cancel ();
m_ResendTimer.cancel ();
}
}
void Stream::ProcessAck (Packet * packet)
{
uint32_t ackThrough = packet->GetAckThrough ();
int nackCount = packet->GetNACKCount ();
for (auto it = m_SentPackets.begin (); it != m_SentPackets.end ();)
{
auto seqn = (*it)->GetSeqn ();
if (seqn <= ackThrough)
{
if (nackCount > 0)
{
bool nacked = false;
for (int i = 0; i < nackCount; i++)
if (seqn == packet->GetNACK (i))
{
nacked = true;
break;
}
if (nacked)
{
LogPrint ("Packet ", seqn, " NACK");
it++;
continue;
}
}
auto sentPacket = *it;
LogPrint ("Packet ", seqn, " acknowledged");
m_SentPackets.erase (it++);
delete sentPacket;
}
else
break;
}
if (m_SentPackets.empty ())
m_ResendTimer.cancel ();
}
size_t Stream::Send (const uint8_t * buf, size_t len, int timeout)
{
bool isNoAck = m_LastReceivedSequenceNumber < 0; // first packet
while (!m_IsOpen || len > 0)
{
Packet * p = new Packet ();
uint8_t * packet = p->GetBuffer ();
// TODO: implement setters
size_t size = 0;
*(uint32_t *)(packet + size) = htobe32 (m_SendStreamID);
size += 4; // sendStreamID
*(uint32_t *)(packet + size) = htobe32 (m_RecvStreamID);
size += 4; // receiveStreamID
*(uint32_t *)(packet + size) = htobe32 (m_SequenceNumber++);
size += 4; // sequenceNum
if (isNoAck)
*(uint32_t *)(packet + size) = htobe32 (m_LastReceivedSequenceNumber);
else
*(uint32_t *)(packet + size) = 0;
size += 4; // ack Through
packet[size] = 0;
size++; // NACK count
size++; // resend delay
if (!m_IsOpen)
{
// initial packet
m_IsOpen = true;
uint16_t flags = PACKET_FLAG_SYNCHRONIZE | PACKET_FLAG_FROM_INCLUDED |
PACKET_FLAG_SIGNATURE_INCLUDED | PACKET_FLAG_MAX_PACKET_SIZE_INCLUDED;
if (isNoAck) flags |= PACKET_FLAG_NO_ACK;
*(uint16_t *)(packet + size) = htobe16 (flags);
size += 2; // flags
*(uint16_t *)(packet + size) = htobe16 (i2p::data::DEFAULT_IDENTITY_SIZE + 40 + 2); // identity + signature + packet size
size += 2; // options size
memcpy (packet + size, &m_LocalDestination->GetIdentity (), i2p::data::DEFAULT_IDENTITY_SIZE);
size += i2p::data::DEFAULT_IDENTITY_SIZE; // from
*(uint16_t *)(packet + size) = htobe16 (STREAMING_MTU);
size += 2; // max packet size
uint8_t * signature = packet + size; // set it later
memset (signature, 0, 40); // zeroes for now
size += 40; // signature
size_t sentLen = STREAMING_MTU - size;
if (len < sentLen) sentLen = len;
memcpy (packet + size, buf, sentLen);
buf += sentLen;
len -= sentLen;
size += sentLen; // payload
m_LocalDestination->Sign (packet, size, signature);
}
else
{
// follow on packet
*(uint16_t *)(packet + size) = 0;
size += 2; // flags
*(uint16_t *)(packet + size) = 0; // no options
size += 2; // options size
size_t sentLen = STREAMING_MTU - size;
if (len < sentLen) sentLen = len;
memcpy (packet + size, buf, sentLen);
buf += sentLen;
len -= sentLen;
size += sentLen; // payload
}
p->len = size;
m_Service.post (boost::bind (&Stream::SendPacket, this, p));
}
return len;
}
void Stream::SendQuickAck ()
{
Packet p;
uint8_t * packet = p.GetBuffer ();
size_t size = 0;
*(uint32_t *)(packet + size) = htobe32 (m_SendStreamID);
size += 4; // sendStreamID
*(uint32_t *)(packet + size) = htobe32 (m_RecvStreamID);
size += 4; // receiveStreamID
*(uint32_t *)(packet + size) = 0; // this is plain Ack message
size += 4; // sequenceNum
*(uint32_t *)(packet + size) = htobe32 (m_LastReceivedSequenceNumber);
size += 4; // ack Through
packet[size] = 0;
size++; // NACK count
size++; // resend delay
*(uint16_t *)(packet + size) = 0; // nof flags set
size += 2; // flags
*(uint16_t *)(packet + size) = 0; // no options
size += 2; // options size
p.len = size;
SendPackets (std::vector<Packet *> { &p });
LogPrint ("Quick Ack sent");
}
void Stream::Close ()
{
if (m_IsOpen)
{
m_IsOpen = false;
Packet * p = new Packet ();
uint8_t * packet = p->GetBuffer ();
size_t size = 0;
*(uint32_t *)(packet + size) = htobe32 (m_SendStreamID);
size += 4; // sendStreamID
*(uint32_t *)(packet + size) = htobe32 (m_RecvStreamID);
size += 4; // receiveStreamID
*(uint32_t *)(packet + size) = htobe32 (m_SequenceNumber++);
size += 4; // sequenceNum
*(uint32_t *)(packet + size) = htobe32 (m_LastReceivedSequenceNumber);
size += 4; // ack Through
packet[size] = 0;
size++; // NACK count
size++; // resend delay
*(uint16_t *)(packet + size) = htobe16 (PACKET_FLAG_CLOSE | PACKET_FLAG_SIGNATURE_INCLUDED);
size += 2; // flags
*(uint16_t *)(packet + size) = htobe16 (40); // 40 bytes signature
size += 2; // options size
uint8_t * signature = packet + size;
memset (packet + size, 0, 40);
size += 40; // signature
m_LocalDestination->Sign (packet, size, signature);
p->len = size;
m_Service.post (boost::bind (&Stream::SendPacket, this, p));
LogPrint ("FIN sent");
}
}
size_t Stream::ConcatenatePackets (uint8_t * buf, size_t len)
{
size_t pos = 0;
while (pos < len && !m_ReceiveQueue.empty ())
{
Packet * packet = m_ReceiveQueue.front ();
size_t l = std::min (packet->GetLength (), len - pos);
memcpy (buf + pos, packet->GetBuffer (), l);
pos += l;
packet->offset += l;
if (!packet->GetLength ())
{
m_ReceiveQueue.pop ();
delete packet;
}
}
return pos;
}
bool Stream::SendPacket (Packet * packet)
{
if (packet)
{
SendPackets (std::vector<Packet *> { packet });
bool isEmpty = m_SentPackets.empty ();
m_SentPackets.insert (packet);
if (isEmpty)
ScheduleResend ();
return true;
}
else
return false;
}
void Stream::SendPackets (const std::vector<Packet *>& packets)
{
if (!m_RemoteLeaseSet)
{
UpdateCurrentRemoteLease ();
if (!m_RemoteLeaseSet)
{
LogPrint ("Can't send packets. Missing remote LeaseSet");
return;
}
}
const i2p::data::LeaseSet * leaseSet = nullptr;
if (m_LeaseSetUpdated)
{
leaseSet = m_LocalDestination->GetLeaseSet ();
m_LeaseSetUpdated = false;
}
auto outboundTunnel = m_LocalDestination->GetTunnelPool ()->GetNextOutboundTunnel ();
if (outboundTunnel)
{
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
if (ts >= m_CurrentRemoteLease.endDate)
UpdateCurrentRemoteLease ();
if (ts < m_CurrentRemoteLease.endDate)
{
std::vector<i2p::tunnel::TunnelMessageBlock> msgs;
for (auto it: packets)
{
auto msg = i2p::garlic::routing.WrapMessage (*m_RemoteLeaseSet,
CreateDataMessage (this, it->GetBuffer (), it->GetLength ()), leaseSet);
msgs.push_back (i2p::tunnel::TunnelMessageBlock
{
i2p::tunnel::eDeliveryTypeTunnel,
m_CurrentRemoteLease.tunnelGateway, m_CurrentRemoteLease.tunnelID,
msg
});
leaseSet = nullptr; // send leaseSet only one time
}
outboundTunnel->SendTunnelDataMsg (msgs);
}
else
LogPrint ("All leases are expired");
}
else
LogPrint ("No outbound tunnels in the pool");
}
void Stream::ScheduleResend ()
{
m_ResendTimer.cancel ();
m_ResendTimer.expires_from_now (boost::posix_time::seconds(RESEND_TIMEOUT));
m_ResendTimer.async_wait (boost::bind (&Stream::HandleResendTimer,
this, boost::asio::placeholders::error));
}
void Stream::HandleResendTimer (const boost::system::error_code& ecode)
{
if (ecode != boost::asio::error::operation_aborted)
{
std::vector<Packet *> packets;
for (auto it : m_SentPackets)
{
it->numResendAttempts++;
if (it->numResendAttempts <= MAX_NUM_RESEND_ATTEMPTS)
packets.push_back (it);
else
{
Close ();
m_ReceiveTimer.cancel ();
return;
}
}
if (packets.size () > 0)
{
UpdateCurrentRemoteLease (); // pick another lease
SendPackets (packets);
}
ScheduleResend ();
}
}
void Stream::UpdateCurrentRemoteLease ()
{
if (!m_RemoteLeaseSet)
{
m_RemoteLeaseSet = i2p::data::netdb.FindLeaseSet (m_RemoteIdentity.Hash ());
if (!m_RemoteLeaseSet)
LogPrint ("LeaseSet ", m_RemoteIdentity.Hash ().ToBase64 (), " not found");
}
if (m_RemoteLeaseSet)
{
auto leases = m_RemoteLeaseSet->GetNonExpiredLeases ();
if (!leases.empty ())
{
uint32_t i = i2p::context.GetRandomNumberGenerator ().GenerateWord32 (0, leases.size () - 1);
m_CurrentRemoteLease = leases[i];
}
else
m_CurrentRemoteLease.endDate = 0;
}
else
m_CurrentRemoteLease.endDate = 0;
}
StreamingDestination::StreamingDestination (boost::asio::io_service& service):
m_Service (service), m_LeaseSet (nullptr)
{
m_Keys = i2p::data::CreateRandomKeys ();
m_IdentHash = m_Keys.pub.Hash ();
m_SigningPrivateKey.Initialize (i2p::crypto::dsap, i2p::crypto::dsaq, i2p::crypto::dsag,
CryptoPP::Integer (m_Keys.signingPrivateKey, 20));
CryptoPP::DH dh (i2p::crypto::elgp, i2p::crypto::elgg);
dh.GenerateKeyPair(i2p::context.GetRandomNumberGenerator (), m_EncryptionPrivateKey, m_EncryptionPublicKey);
m_Pool = i2p::tunnel::tunnels.CreateTunnelPool (*this, 3); // 3-hops tunnel
}
StreamingDestination::StreamingDestination (boost::asio::io_service& service, const std::string& fullPath):
m_Service (service), m_LeaseSet (nullptr)
{
std::ifstream s(fullPath.c_str (), std::ifstream::binary);
if (s.is_open ())
s.read ((char *)&m_Keys, sizeof (m_Keys));
else
LogPrint ("Can't open file ", fullPath);
m_IdentHash = m_Keys.pub.Hash ();
m_SigningPrivateKey.Initialize (i2p::crypto::dsap, i2p::crypto::dsaq, i2p::crypto::dsag,
CryptoPP::Integer (m_Keys.signingPrivateKey, 20));
CryptoPP::DH dh (i2p::crypto::elgp, i2p::crypto::elgg);
dh.GenerateKeyPair(i2p::context.GetRandomNumberGenerator (), m_EncryptionPrivateKey, m_EncryptionPublicKey);
m_Pool = i2p::tunnel::tunnels.CreateTunnelPool (*this, 3); // 3-hops tunnel
}
StreamingDestination::~StreamingDestination ()
{
if (m_Pool)
i2p::tunnel::tunnels.DeleteTunnelPool (m_Pool);
delete m_LeaseSet;
}
void StreamingDestination::HandleNextPacket (Packet * packet)
{
uint32_t sendStreamID = packet->GetSendStreamID ();
if (sendStreamID)
{
auto it = m_Streams.find (sendStreamID);
if (it != m_Streams.end ())
it->second->HandleNextPacket (packet);
else
{
LogPrint ("Unknown stream ", sendStreamID);
delete packet;
}
}
else // new incoming stream
{
auto incomingStream = CreateNewIncomingStream ();
incomingStream->HandleNextPacket (packet);
if (m_Acceptor != nullptr)
m_Acceptor (incomingStream);
}
}
Stream * StreamingDestination::CreateNewOutgoingStream (const i2p::data::LeaseSet& remote)
{
Stream * s = new Stream (m_Service, this, remote);
m_Streams[s->GetRecvStreamID ()] = s;
return s;
}
Stream * StreamingDestination::CreateNewIncomingStream ()
{
Stream * s = new Stream (m_Service, this);
m_Streams[s->GetRecvStreamID ()] = s;
return s;
}
void StreamingDestination::DeleteStream (Stream * stream)
{
if (stream)
{
m_Streams.erase (stream->GetRecvStreamID ());
delete stream;
}
}
const i2p::data::LeaseSet * StreamingDestination::GetLeaseSet ()
{
if (!m_Pool) return nullptr;
if (!m_LeaseSet)
UpdateLeaseSet ();
return m_LeaseSet;
}
void StreamingDestination::UpdateLeaseSet ()
{
auto newLeaseSet = new i2p::data::LeaseSet (*m_Pool);
if (!m_LeaseSet)
m_LeaseSet = newLeaseSet;
else
{
// TODO: implement it better
*m_LeaseSet = *newLeaseSet;
delete newLeaseSet;
}
}
void StreamingDestination::SetLeaseSetUpdated ()
{
UpdateLeaseSet ();
for (auto it: m_Streams)
it.second->SetLeaseSetUpdated ();
}
void StreamingDestination::Sign (const uint8_t * buf, int len, uint8_t * signature) const
{
CryptoPP::DSA::Signer signer (m_SigningPrivateKey);
signer.SignMessage (i2p::context.GetRandomNumberGenerator (), buf, len, signature);
}
StreamingDestinations destinations;
void StreamingDestinations::Start ()
{
if (!m_SharedLocalDestination)
{
m_SharedLocalDestination = new StreamingDestination (m_Service);
m_Destinations[m_SharedLocalDestination->GetIdentHash ()] = m_SharedLocalDestination;
}
LoadLocalDestinations ();
m_IsRunning = true;
m_Thread = new std::thread (std::bind (&StreamingDestinations::Run, this));
}
void StreamingDestinations::Stop ()
{
for (auto it: m_Destinations)
delete it.second;
m_Destinations.clear ();
m_SharedLocalDestination = 0; // deleted through m_Destination
m_IsRunning = false;
m_Service.stop ();
if (m_Thread)
{
m_Thread->join ();
delete m_Thread;
m_Thread = 0;
}
}
void StreamingDestinations::Run ()
{
m_Service.run ();
}
void StreamingDestinations::LoadLocalDestinations ()
{
int numDestinations = 0;
boost::filesystem::path p (i2p::util::filesystem::GetDataDir());
boost::filesystem::directory_iterator end;
for (boost::filesystem::directory_iterator it (p); it != end; ++it)
{
if (boost::filesystem::is_regular_file (*it) && it->path ().extension () == ".dat")
{
auto fullPath =
#if BOOST_VERSION > 10500
it->path().string();
#else
it->path();
#endif
auto localDestination = new StreamingDestination (m_Service, fullPath);
m_Destinations[localDestination->GetIdentHash ()] = localDestination;
numDestinations++;
}
}
if (numDestinations > 0)
LogPrint (numDestinations, " local destinations loaded");
}
Stream * StreamingDestinations::CreateClientStream (const i2p::data::LeaseSet& remote)
{
if (!m_SharedLocalDestination) return nullptr;
return m_SharedLocalDestination->CreateNewOutgoingStream (remote);
}
void StreamingDestinations::DeleteStream (Stream * stream)
{
if (stream)
{
m_Service.post (
[=](void)
{
stream->GetLocalDestination ()->DeleteStream (stream);
}
);
}
}
void StreamingDestinations::HandleNextPacket (i2p::data::IdentHash destination, Packet * packet)
{
m_Service.post (boost::bind (&StreamingDestinations::PostNextPacket, this, destination, packet));
}
void StreamingDestinations::PostNextPacket (i2p::data::IdentHash destination, Packet * packet)
{
auto it = m_Destinations.find (destination);
if (it != m_Destinations.end ())
it->second->HandleNextPacket (packet);
else
{
LogPrint ("Local destination ", destination.ToBase64 (), " not found");
delete packet;
}
}
Stream * CreateStream (const i2p::data::LeaseSet& remote)
{
return destinations.CreateClientStream (remote);
}
void DeleteStream (Stream * stream)
{
destinations.DeleteStream (stream);
}
void StartStreaming ()
{
destinations.Start ();
}
void StopStreaming ()
{
destinations.Stop ();
}
StreamingDestination * GetSharedLocalDestination ()
{
return destinations.GetSharedLocalDestination ();
}
void HandleDataMessage (i2p::data::IdentHash destination, const uint8_t * buf, size_t len)
{
uint32_t length = be32toh (*(uint32_t *)buf);
buf += 4;
// we assume I2CP payload
if (buf[9] == 6) // streaming protocol
{
// unzip it
CryptoPP::Gunzip decompressor;
decompressor.Put (buf, length);
decompressor.MessageEnd();
Packet * uncompressed = new Packet;
uncompressed->offset = 0;
uncompressed->len = decompressor.MaxRetrievable ();
if (uncompressed->len > MAX_PACKET_SIZE)
{
LogPrint ("Received packet size ", uncompressed->len, " exceeds max packet size");
uncompressed->len = MAX_PACKET_SIZE;
}
decompressor.Get (uncompressed->buf, uncompressed->len);
// then forward to streaming engine thread
destinations.HandleNextPacket (destination, uncompressed);
}
else
LogPrint ("Data: protocol ", buf[9], " is not supported");
}
I2NPMessage * CreateDataMessage (Stream * s, const uint8_t * payload, size_t len)
{
I2NPMessage * msg = NewI2NPShortMessage ();
CryptoPP::Gzip compressor; // DEFAULT_DEFLATE_LEVEL
if (len <= COMPRESSION_THRESHOLD_SIZE)
compressor.SetDeflateLevel (CryptoPP::Gzip::MIN_DEFLATE_LEVEL);
compressor.Put (payload, len);
compressor.MessageEnd();
int size = compressor.MaxRetrievable ();
uint8_t * buf = msg->GetPayload ();
*(uint32_t *)buf = htobe32 (size); // length
buf += 4;
compressor.Get (buf, size);
memset (buf + 4, 0, 4); // source and destination ports. TODO: fill with proper values later
buf[9] = 6; // streaming protocol
msg->len += size + 4;
FillI2NPMessageHeader (msg, eI2NPData);
return msg;
}
}
}