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)
{
}
void DatagramDestination::SendDatagramTo (const uint8_t * payload, size_t len, const i2p::data::LeaseSet& remote)
{
uint8_t buf[MAX_DATAGRAM_SIZE];
auto identityLen = m_Owner.GetIdentity ().ToBuffer (buf, MAX_DATAGRAM_SIZE);
uint8_t * signature = buf + identityLen;
auto signatureLen = m_Owner.GetIdentity ().GetSignatureLen ();
uint8_t * buf1 = signature + signatureLen;
size_t headerLen = identityLen + signatureLen;
memcpy (buf1, payload, len);
if (m_Owner.GetIdentity ().GetSigningKeyType () == i2p::data::SIGNING_KEY_TYPE_DSA_SHA1)
{
uint8_t hash[32];
CryptoPP::SHA256().CalculateDigest (hash, buf1, len);
m_Owner.Sign (hash, 32, signature);
}
else
m_Owner.Sign (buf1, len, signature);
auto service = m_Owner.GetService ();
if (service)
service->post (boost::bind (&DatagramDestination::SendMsg, this,
CreateDataMessage (buf, len + headerLen), remote));
else
LogPrint ("Failed to send datagram. Destination is not running");
}
void DatagramDestination::SendMsg (I2NPMessage * msg, const i2p::data::LeaseSet& remote)
{
auto leases = remote.GetNonExpiredLeases ();
if (!leases.empty ())
{
std::vector<i2p::tunnel::TunnelMessageBlock> msgs;
uint32_t i = i2p::context.GetRandomNumberGenerator ().GenerateWord32 (0, leases.size () - 1);
auto garlic = m_Owner.WrapMessage (remote, msg, true);
msgs.push_back (i2p::tunnel::TunnelMessageBlock
{
i2p::tunnel::eDeliveryTypeTunnel,
leases[i].tunnelGateway, leases[i].tunnelID,
garlic
});
m_Owner.SendTunnelDataMsgs (msgs);
}
else
{
LogPrint ("Failed to send datagram. All leases expired");
DeleteI2NPMessage (msg);
}
}
void DatagramDestination::HandleDatagram (const uint8_t * buf, size_t len)
{
i2p::data::IdentityEx identity;
size_t identityLen = identity.FromBuffer (buf, len);
const uint8_t * signature = buf + identityLen;
size_t headerLen = identityLen + identity.GetSignatureLen ();
bool verified = false;
if (identity.GetSigningKeyType () == i2p::data::SIGNING_KEY_TYPE_DSA_SHA1)
{
uint8_t hash[32];
CryptoPP::SHA256().CalculateDigest (hash, buf + headerLen, len - headerLen);
verified = identity.Verify (hash, 32, signature);
}
else
verified = identity.Verify (buf + headerLen, len - headerLen, signature);
if (verified)
{
// TODO: invoke datagram handler
}
else
LogPrint ("Datagram signature verification failed");
}
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);
HandleDatagram (uncompressed, uncompressedLen);
}
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;
}
}
}