I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <string.h>
#include <vector>
#include <cryptopp/sha.h>
#include <cryptopp/gzip.h>
#include "Log.h"
#include "TunnelBase.h"
#include "RouterContext.h"
#include "Destination.h"
#include "Datagram.h"
namespace i2p
{
namespace datagram
{
DatagramDestination::DatagramDestination (i2p::client::ClientDestination& owner):
m_Owner (owner)
{
auto identityLen = m_Owner.GetIdentity ().ToBuffer (m_OutgoingBuffer, MAX_DATAGRAM_SIZE);
m_Signature = m_OutgoingBuffer + identityLen;
auto signatureLen = m_Owner.GetIdentity ().GetSignatureLen ();
m_Payload = m_Signature + signatureLen;
m_HeaderLen = identityLen + signatureLen;
}
void DatagramDestination::SendDatagramTo (const uint8_t * payload, size_t len, const i2p::data::LeaseSet& remote)
{
auto leases = remote.GetNonExpiredLeases ();
if (!leases.empty ())
{
memcpy (m_Payload, payload, len);
if (m_Owner.GetIdentity ().GetSigningKeyType () == i2p::data::SIGNING_KEY_TYPE_DSA_SHA1)
{
uint8_t hash[32];
CryptoPP::SHA256().CalculateDigest (hash, m_Payload, len);
m_Owner.Sign (hash, 32, m_Signature);
}
else
m_Owner.Sign (m_Payload, len, m_Signature);
std::vector<i2p::tunnel::TunnelMessageBlock> msgs;
uint32_t i = i2p::context.GetRandomNumberGenerator ().GenerateWord32 (0, leases.size () - 1);
auto msg = m_Owner.WrapMessage (remote, CreateDataMessage (m_OutgoingBuffer, len + m_HeaderLen), true);
msgs.push_back (i2p::tunnel::TunnelMessageBlock
{
i2p::tunnel::eDeliveryTypeTunnel,
leases[i].tunnelGateway, leases[i].tunnelID,
msg
});
m_Owner.SendTunnelDataMsgs (msgs);
}
else
LogPrint ("Failed to send datagram. All leases expired");
}
void DatagramDestination::HandleDataMessagePayload (const uint8_t * buf, size_t len)
{
// unzip it
CryptoPP::Gunzip decompressor;
decompressor.Put (buf, len);
decompressor.MessageEnd();
uint8_t uncompressed[MAX_DATAGRAM_SIZE];
auto uncompressedLen = decompressor.MaxRetrievable ();
if (uncompressedLen <= MAX_DATAGRAM_SIZE)
{
decompressor.Get (uncompressed, uncompressedLen);
//HandleNextPacket (uncompressed);
}
else
LogPrint ("Received datagram size ", uncompressedLen, " exceeds max size");
}
I2NPMessage * DatagramDestination::CreateDataMessage (const uint8_t * payload, size_t len)
{
I2NPMessage * msg = NewI2NPMessage ();
CryptoPP::Gzip compressor; // default 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 are zeroes
buf[9] = i2p::client::PROTOCOL_TYPE_DATAGRAM; // datagram protocol
msg->len += size + 4;
FillI2NPMessageHeader (msg, eI2NPData);
return msg;
}
}
}