I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <endian.h>
#include <string>
#include <cryptopp/gzip.h>
#include "Log.h"
#include "RouterInfo.h"
#include "RouterContext.h"
#include "Tunnel.h"
#include "Timestamp.h"
#include "CryptoConst.h"
#include "Garlic.h"
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#include "Streaming.h"
namespace i2p
{
namespace stream
{
Stream::Stream (StreamingDestination * local, const i2p::data::LeaseSet * remote):
m_SendStreamID (0), m_SequenceNumber (0), m_LocalDestination (local), m_RemoteLeaseSet (remote)
{
m_RecvStreamID = i2p::context.GetRandomNumberGenerator ().GenerateWord32 ();
}
void Stream::HandleNextPacket (const uint8_t * buf, size_t len)
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{
const uint8_t * end = buf + len;
buf += 4; // sendStreamID
buf += 4; // receiveStreamID
buf += 4; // sequenceNum
buf += 4; // ackThrough
int nackCount = buf[0];
buf++; // NACK count
buf += 4*nackCount; // NACKs
buf++; // resendDelay
uint16_t flags = be16toh (*(uint16_t *)buf);
buf += 2; // flags
uint16_t optionalSize = be16toh (*(uint16_t *)buf);
buf += 2; // optional size
const uint8_t * optionalData = buf;
buf += optionalSize;
// process flags
if (flags & PACKET_FLAG_SYNCHRONIZE)
{
LogPrint ("Synchronize");
}
if (flags & PACKET_FLAG_SIGNATURE_INCLUDED)
{
LogPrint ("Signature");
optionalData += 40;
}
if (flags & PACKET_FLAG_FROM_INCLUDED)
{
LogPrint ("From identity");
optionalData += sizeof (i2p::data::Identity);
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}
// we have reached payload section
std::string str((const char *)buf, end-buf);
LogPrint ("Payload: ", str);
}
size_t Stream::Send (uint8_t * buf, size_t len, int timeout)
{
uint8_t packet[STREAMING_MTU];
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) = 0; // TODO
size += 4; // ack Through
packet[size] = 0;
size++; // NACK count
size++; // resend delay
// TODO: for initial packet only, following packets have different falgs
*(uint16_t *)(packet + size) = htobe16 (PACKET_FLAG_SYNCHRONIZE |
PACKET_FLAG_FROM_INCLUDED | PACKET_FLAG_SIGNATURE_INCLUDED | PACKET_FLAG_NO_ACK);
size += 2; // flags
*(uint16_t *)(packet + size) = htobe16 (sizeof (i2p::data::Identity) + 40); // identity + signature
size += 2; // options size
memcpy (packet + size, &m_LocalDestination->GetIdentity (), sizeof (i2p::data::Identity));
size += sizeof (i2p::data::Identity); // from
uint8_t * signature = packet + size; // set it later
memset (signature, 0, 40); // zeroes for now
size += 40; // signature
memcpy (packet + size, buf, len);
size += len; // payload
m_LocalDestination->Sign (packet, size, signature);
I2NPMessage * msg = i2p::garlic::routing.WrapSingleMessage (m_RemoteLeaseSet,
CreateDataMessage (this, packet, size), m_LocalDestination->CreateLeaseSet ());
auto outbound = i2p::tunnel::tunnels.GetNextOutboundTunnel ();
if (outbound)
{
auto lease = m_RemoteLeaseSet->GetLeases ()[0]; // TODO:
outbound->SendTunnelDataMsg (lease.tunnelGateway, lease.tunnelID, msg);
}
else
DeleteI2NPMessage (msg);
return len;
}
StreamingDestination * sharedLocalDestination = nullptr;
StreamingDestination::StreamingDestination ()
{
// TODO: read from file later
m_Keys = i2p::data::CreateRandomKeys ();
m_Identity = m_Keys;
m_IdentHash = i2p::data::CalculateIdentHash (m_Identity);
m_SigningPrivateKey.Initialize (i2p::crypto::dsap, i2p::crypto::dsaq, i2p::crypto::dsag,
CryptoPP::Integer (m_Keys.signingPrivateKey, 20));
}
void StreamingDestination::HandleNextPacket (const uint8_t * buf, size_t len)
{
uint32_t sendStreamID = *(uint32_t *)(buf);
auto it = m_Streams.find (sendStreamID);
if (it != m_Streams.end ())
it->second->HandleNextPacket (buf, len);
else
LogPrint ("Unknown stream ", sendStreamID);
}
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Stream * StreamingDestination::CreateNewStream (const i2p::data::LeaseSet * remote)
{
Stream * s = new Stream (this, remote);
m_Streams[s->GetRecvStreamID ()] = s;
return s;
}
void StreamingDestination::DeleteStream (Stream * stream)
{
if (stream)
{
m_Streams.erase (stream->GetRecvStreamID ());
delete stream;
}
}
I2NPMessage * StreamingDestination::CreateLeaseSet () const
{
I2NPMessage * m = NewI2NPMessage ();
I2NPDatabaseStoreMsg * msg = (I2NPDatabaseStoreMsg *)m->GetPayload ();
memcpy (msg->key, (const uint8_t *)m_IdentHash, 32);
msg->type = 1; // LeaseSet
msg->replyToken = 0;
uint8_t * buf = m->GetPayload () + sizeof (I2NPDatabaseStoreMsg);
size_t size = 0;
memcpy (buf + size, &m_Identity, sizeof (m_Identity));
size += sizeof (m_Identity); // destination
memcpy (buf + size, i2p::context.GetLeaseSetPublicKey (), 256);
size += 256; // encryption key
memset (buf + size, 0, 128);
size += 128; // signing key
auto tunnel = i2p::tunnel::tunnels.GetNextInboundTunnel ();
if (tunnel)
{
buf[size] = 1; // 1 lease
size++; // num
memcpy (buf + size, (const uint8_t *)tunnel->GetNextIdentHash (), 32);
size += 32; // tunnel_gw
*(uint32_t *)(buf + size) = htobe32 (tunnel->GetNextTunnelID ());
size += 4; // tunnel_id
uint64_t ts = tunnel->GetCreationTime () + i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT;
ts *= 1000; // in milliseconds
*(uint64_t *)(buf + size) = htobe64 (ts);
size += 8; // end_date
}
else
{
buf[size] = 0; // zero leases
size++; // num
}
Sign (buf, size, buf+ size);
size += 40; // signature
m->len += size + sizeof (I2NPDatabaseStoreMsg);
FillI2NPMessageHeader (m, eI2NPDatabaseStore);
return m;
}
void StreamingDestination::Sign (uint8_t * buf, int len, uint8_t * signature) const
{
CryptoPP::DSA::Signer signer (m_SigningPrivateKey);
signer.SignMessage (i2p::context.GetRandomNumberGenerator (), buf, len, signature);
}
Stream * CreateStream (const i2p::data::LeaseSet * remote)
{
if (!sharedLocalDestination)
sharedLocalDestination = new StreamingDestination ();
return sharedLocalDestination->CreateNewStream (remote);
}
void CloseStream (Stream * stream)
{
if (sharedLocalDestination)
sharedLocalDestination->DeleteStream (stream);
}
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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();
uint8_t uncompressed[2048];
int uncompressedSize = decompressor.MaxRetrievable ();
decompressor.Get (uncompressed, uncompressedSize);
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// then forward to streaming engine
// TODO: we have onle one destination, might be more
if (sharedLocalDestination)
sharedLocalDestination->HandleNextPacket (uncompressed, uncompressedSize);
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}
else
LogPrint ("Data: protocol ", buf[9], " is not supported");
}
I2NPMessage * CreateDataMessage (Stream * s, uint8_t * payload, size_t len)
{
I2NPMessage * msg = NewI2NPMessage ();
CryptoPP::Gzip compressor;
compressor.Put (payload, len);
compressor.MessageEnd();
int size = compressor.MaxRetrievable ();
uint8_t * buf = msg->GetPayload ();
*(uint16_t *)buf = htobe32 (size); // length
buf += 4;
compressor.Get (buf, size);
buf[9] = 6; // streaming protocol
msg->len += size + 4;
FillI2NPMessageHeader (msg, eI2NPData);
return msg;
}
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}
}