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i2pd/Streaming.cpp

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#include <cryptopp/gzip.h>
#include "Log.h"
#include "RouterInfo.h"
#include "RouterContext.h"
#include "Tunnel.h"
#include "Timestamp.h"
#include "Destination.h"
#include "Streaming.h"
namespace i2p
{
namespace stream
{
Stream::Stream (boost::asio::io_service& service, StreamingDestination& local,
const i2p::data::LeaseSet& remote, int port): m_Service (service), m_SendStreamID (0),
m_SequenceNumber (0), m_LastReceivedSequenceNumber (-1), m_IsOpen (false),
m_IsReset (false), m_IsAckSendScheduled (false), m_LocalDestination (local),
m_RemoteLeaseSet (&remote), m_RoutingSession (nullptr), m_CurrentOutboundTunnel (nullptr),
m_ReceiveTimer (m_Service), m_ResendTimer (m_Service), m_AckSendTimer (m_Service),
m_NumSentBytes (0), m_NumReceivedBytes (0), m_Port (port)
{
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_IsReset (false), m_IsAckSendScheduled (false), m_LocalDestination (local),
m_RemoteLeaseSet (nullptr), m_RoutingSession (nullptr), m_CurrentOutboundTunnel (nullptr),
m_ReceiveTimer (m_Service), m_ResendTimer (m_Service), m_AckSendTimer (m_Service),
m_NumSentBytes (0), m_NumReceivedBytes (0), m_Port (0)
{
m_RecvStreamID = i2p::context.GetRandomNumberGenerator ().GenerateWord32 ();
}
Stream::~Stream ()
{
m_AckSendTimer.cancel ();
while (!m_ReceiveQueue.empty ())
{
auto packet = m_ReceiveQueue.front ();
m_ReceiveQueue.pop ();
delete packet;
}
m_ReceiveTimer.cancel ();
for (auto it: m_SentPackets)
delete it;
m_SentPackets.clear ();
m_ResendTimer.cancel ();
for (auto it: m_SavedPackets)
delete it;
m_SavedPackets.clear ();
LogPrint (eLogDebug, "Stream deleted");
}
void Stream::HandleNextPacket (Packet * packet)
{
m_NumReceivedBytes += packet->GetLength ();
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 (eLogDebug, "Plain ACK received");
delete packet;
return;
}
LogPrint (eLogDebug, "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;
}
// schedule ack for last message
if (m_IsOpen)
{
if (!m_IsAckSendScheduled)
{
m_IsAckSendScheduled = true;
m_AckSendTimer.expires_from_now (boost::posix_time::milliseconds(ACK_SEND_TIMEOUT));
m_AckSendTimer.async_wait (std::bind (&Stream::HandleAckSendTimer,
shared_from_this (), std::placeholders::_1));
}
}
else if (isSyn)
// we have to send SYN back to incoming connection
Send (nullptr, 0); // also sets m_IsOpen
}
else
{
if (receivedSeqn <= m_LastReceivedSequenceNumber)
{
// we have received duplicate. Most likely our outbound tunnel is dead
LogPrint (eLogWarning, "Duplicate message ", receivedSeqn, " received");
m_CurrentOutboundTunnel = nullptr; // pick another outbound tunnel
UpdateCurrentRemoteLease (); // pick another lease
SendQuickAck (); // resend ack for previous message again
delete packet; // packet dropped
}
else
{
LogPrint (eLogWarning, "Missing messages from ", m_LastReceivedSequenceNumber + 1, " to ", receivedSeqn - 1);
// save message and wait for missing message again
SavePacket (packet);
// send NACKs for missing messages ASAP
if (m_IsAckSendScheduled)
{
m_IsAckSendScheduled = false;
m_AckSendTimer.cancel ();
}
SendQuickAck ();
}
}
}
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 (eLogDebug, "Process seqn=", receivedSeqn, ", flags=", flags);
const uint8_t * optionData = packet->GetOptionData ();
if (flags & PACKET_FLAG_SYNCHRONIZE)
LogPrint (eLogDebug, "Synchronize");
if (flags & PACKET_FLAG_DELAY_REQUESTED)
{
optionData += 2;
}
if (flags & PACKET_FLAG_FROM_INCLUDED)
{
optionData += m_RemoteIdentity.FromBuffer (optionData, packet->GetOptionSize ());
LogPrint (eLogInfo, "From identity ", m_RemoteIdentity.GetIdentHash ().ToBase64 ());
if (!m_RemoteLeaseSet)
LogPrint (eLogDebug, "Incoming stream from ", m_RemoteIdentity.GetIdentHash ().ToBase64 ());
}
if (flags & PACKET_FLAG_MAX_PACKET_SIZE_INCLUDED)
{
uint16_t maxPacketSize = be16toh (*(uint16_t *)optionData);
LogPrint (eLogDebug, "Max packet size ", maxPacketSize);
optionData += 2;
}
if (flags & PACKET_FLAG_SIGNATURE_INCLUDED)
{
LogPrint (eLogDebug, "Signature");
uint8_t signature[256];
auto signatureLen = m_RemoteIdentity.GetSignatureLen ();
memcpy (signature, optionData, signatureLen);
memset (const_cast<uint8_t *>(optionData), 0, signatureLen);
if (!m_RemoteIdentity.Verify (packet->GetBuffer (), packet->GetLength (), signature))
{
LogPrint (eLogError, "Signature verification failed");
Close ();
flags |= PACKET_FLAG_CLOSE;
}
memcpy (const_cast<uint8_t *>(optionData), signature, signatureLen);
optionData += signatureLen;
}
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 (eLogInfo, "Closed");
Close ();
m_IsOpen = false;
m_IsReset = true;
}
}
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 (eLogDebug, "Packet ", seqn, " NACK");
it++;
continue;
}
}
auto sentPacket = *it;
LogPrint (eLogDebug, "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)
{
bool isNoAck = m_LastReceivedSequenceNumber < 0; // first packet
std::vector<Packet *> packets;
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; m_IsReset = false;
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
size_t identityLen = m_LocalDestination.GetOwner ().GetIdentity ().GetFullLen ();
size_t signatureLen = m_LocalDestination.GetOwner ().GetIdentity ().GetSignatureLen ();
*(uint16_t *)(packet + size) = htobe16 (identityLen + signatureLen + 2); // identity + signature + packet size
size += 2; // options size
m_LocalDestination.GetOwner ().GetIdentity ().ToBuffer (packet + size, identityLen);
size += identityLen; // from
*(uint16_t *)(packet + size) = htobe16 (STREAMING_MTU);
size += 2; // max packet size
uint8_t * signature = packet + size; // set it later
memset (signature, 0, signatureLen); // zeroes for now
size += signatureLen; // 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.GetOwner ().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;
packets.push_back (p);
}
if (packets.size () > 0)
m_Service.post (std::bind (&Stream::PostPackets, shared_from_this (), packets));
return len;
}
void Stream::SendQuickAck ()
{
int32_t lastReceivedSeqn = m_LastReceivedSequenceNumber;
if (!m_SavedPackets.empty ())
{
int32_t seqn = (*m_SavedPackets.rbegin ())->GetSeqn ();
if (seqn > lastReceivedSeqn) lastReceivedSeqn = seqn;
}
if (lastReceivedSeqn < 0)
{
LogPrint (eLogError, "No packets have been received yet");
return;
}
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 (lastReceivedSeqn);
size += 4; // ack Through
if (lastReceivedSeqn > m_LastReceivedSequenceNumber)
{
// fill NACKs
uint8_t * nacks = packet + size + 1;
uint8_t numNacks = 0;
auto nextSeqn = m_LastReceivedSequenceNumber + 1;
for (auto it: m_SavedPackets)
{
auto seqn = it->GetSeqn ();
for (uint32_t i = nextSeqn; i < seqn; i++)
{
*(uint32_t *)nacks = htobe32 (i);
nacks += 4;
numNacks++;
}
nextSeqn = seqn + 1;
}
packet[size] = numNacks;
size++; // NACK count
size += numNacks*4; // NACKs
}
else
{
// No NACKs
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
size_t signatureLen = m_LocalDestination.GetOwner ().GetIdentity ().GetSignatureLen ();
*(uint16_t *)(packet + size) = htobe16 (signatureLen); // signature only
size += 2; // options size
uint8_t * signature = packet + size;
memset (packet + size, 0, signatureLen);
size += signatureLen; // signature
m_LocalDestination.GetOwner ().Sign (packet, size, signature);
p->len = size;
m_Service.post (std::bind (&Stream::SendPacket, shared_from_this (), p));
LogPrint ("FIN sent");
m_ReceiveTimer.cancel ();
m_LocalDestination.DeleteStream (shared_from_this ());
}
}
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)
{
if (m_IsAckSendScheduled)
{
m_IsAckSendScheduled = false;
m_AckSendTimer.cancel ();
}
SendPackets (std::vector<Packet *> { packet });
if (m_IsOpen)
{
bool isEmpty = m_SentPackets.empty ();
m_SentPackets.insert (packet);
if (isEmpty)
ScheduleResend ();
}
else
delete packet;
return true;
}
else
return false;
}
void Stream::PostPackets (const std::vector<Packet *> packets)
{
if (m_IsOpen)
{
if (packets.size () > 0)
{
m_IsAckSendScheduled = false;
m_AckSendTimer.cancel ();
}
bool isEmpty = m_SentPackets.empty ();
for (auto it: packets)
m_SentPackets.insert (it);
SendPackets (packets);
if (isEmpty)
ScheduleResend ();
}
else
{
// delete
for (auto it: packets)
delete it;
}
}
void Stream::SendPackets (const std::vector<Packet *>& packets)
{
if (!m_RemoteLeaseSet)
{
UpdateCurrentRemoteLease ();
if (!m_RemoteLeaseSet)
{
LogPrint ("Can't send packets. Missing remote LeaseSet");
return;
}
}
m_CurrentOutboundTunnel = m_LocalDestination.GetOwner ().GetTunnelPool ()->GetNextOutboundTunnel (m_CurrentOutboundTunnel);
if (!m_CurrentOutboundTunnel)
{
LogPrint ("No outbound tunnels in the pool");
return;
}
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 = m_RoutingSession->WrapSingleMessage (CreateDataMessage (it->GetBuffer (), it->GetLength ()));
msgs.push_back (i2p::tunnel::TunnelMessageBlock
{
i2p::tunnel::eDeliveryTypeTunnel,
m_CurrentRemoteLease.tunnelGateway, m_CurrentRemoteLease.tunnelID,
msg
});
m_NumSentBytes += it->GetLength ();
}
m_CurrentOutboundTunnel->SendTunnelDataMsg (msgs);
}
else
LogPrint ("All leases are expired");
}
void Stream::ScheduleResend ()
{
m_ResendTimer.cancel ();
m_ResendTimer.expires_from_now (boost::posix_time::seconds(RESEND_TIMEOUT));
m_ResendTimer.async_wait (std::bind (&Stream::HandleResendTimer,
shared_from_this (), std::placeholders::_1));
}
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
{
LogPrint (eLogWarning, "Packet ", it->GetSeqn (), "was not ACKed after ", MAX_NUM_RESEND_ATTEMPTS, " attempts. Terminate");
m_IsOpen = false;
m_IsReset = true;
m_ReceiveTimer.cancel ();
return;
}
}
if (packets.size () > 0)
{
m_CurrentOutboundTunnel = nullptr; // pick another outbound tunnel
UpdateCurrentRemoteLease (); // pick another lease
SendPackets (packets);
}
ScheduleResend ();
}
}
void Stream::HandleAckSendTimer (const boost::system::error_code& ecode)
{
if (m_IsAckSendScheduled)
{
if (m_IsOpen)
SendQuickAck ();
m_IsAckSendScheduled = false;
}
}
void Stream::UpdateCurrentRemoteLease ()
{
if (!m_RemoteLeaseSet)
{
m_RemoteLeaseSet = m_LocalDestination.GetOwner ().FindLeaseSet (m_RemoteIdentity.GetIdentHash ());
if (!m_RemoteLeaseSet)
LogPrint ("LeaseSet ", m_RemoteIdentity.GetIdentHash ().ToBase64 (), " not found");
}
if (m_RemoteLeaseSet)
{
if (!m_RoutingSession)
m_RoutingSession = m_LocalDestination.GetOwner ().GetRoutingSession (*m_RemoteLeaseSet, 32);
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_RemoteLeaseSet = m_LocalDestination.GetOwner ().FindLeaseSet (m_RemoteIdentity.GetIdentHash ()); // re-request expired
m_CurrentRemoteLease.endDate = 0;
}
}
else
m_CurrentRemoteLease.endDate = 0;
}
I2NPMessage * Stream::CreateDataMessage (const uint8_t * payload, size_t len)
{
I2NPMessage * msg = NewI2NPShortMessage ();
CryptoPP::Gzip compressor;
if (len <= i2p::stream::COMPRESSION_THRESHOLD_SIZE)
compressor.SetDeflateLevel (CryptoPP::Gzip::MIN_DEFLATE_LEVEL);
else
compressor.SetDeflateLevel (CryptoPP::Gzip::DEFAULT_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);
*(uint16_t *)(buf + 4) = 0; // source port
*(uint16_t *)(buf + 6) = htobe16 (m_Port); // destination port
buf[9] = i2p::client::PROTOCOL_TYPE_STREAMING; // streaming protocol
msg->len += size + 4;
FillI2NPMessageHeader (msg, eI2NPData);
return msg;
}
void StreamingDestination::Start ()
{
}
void StreamingDestination::Stop ()
{
ResetAcceptor ();
{
std::unique_lock<std::mutex> l(m_StreamsMutex);
m_Streams.clear ();
}
}
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);
else
{
LogPrint ("Acceptor for incoming stream is not set");
DeleteStream (incomingStream);
}
}
}
std::shared_ptr<Stream> StreamingDestination::CreateNewOutgoingStream (const i2p::data::LeaseSet& remote, int port)
{
auto s = std::make_shared<Stream> (m_Owner.GetService (), *this, remote, port);
std::unique_lock<std::mutex> l(m_StreamsMutex);
m_Streams[s->GetRecvStreamID ()] = s;
return s;
}
std::shared_ptr<Stream> StreamingDestination::CreateNewIncomingStream ()
{
auto s = std::make_shared<Stream> (m_Owner.GetService (), *this);
std::unique_lock<std::mutex> l(m_StreamsMutex);
m_Streams[s->GetRecvStreamID ()] = s;
return s;
}
void StreamingDestination::DeleteStream (std::shared_ptr<Stream> stream)
{
if (stream)
{
std::unique_lock<std::mutex> l(m_StreamsMutex);
auto it = m_Streams.find (stream->GetRecvStreamID ());
if (it != m_Streams.end ())
m_Streams.erase (it);
}
}
void StreamingDestination::HandleDataMessagePayload (const uint8_t * buf, size_t len)
{
// unzip it
CryptoPP::Gunzip decompressor;
decompressor.Put (buf, len);
decompressor.MessageEnd();
Packet * uncompressed = new Packet;
uncompressed->offset = 0;
uncompressed->len = decompressor.MaxRetrievable ();
if (uncompressed->len <= MAX_PACKET_SIZE)
{
decompressor.Get (uncompressed->buf, uncompressed->len);
HandleNextPacket (uncompressed);
}
else
{
LogPrint ("Received packet size ", uncompressed->len, " exceeds max packet size. Skipped");
delete uncompressed;
}
}
}
}
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