I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <string.h>
#include <vector>
#include <cryptopp/sha.h>
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#include <cryptopp/gzip.h>
#include "Log.h"
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#include "TunnelBase.h"
#include "RouterContext.h"
#include "Destination.h"
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#include "Datagram.h"
namespace i2p
{
namespace datagram
{
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DatagramDestination::DatagramDestination (i2p::client::ClientDestination& owner):
m_Owner (owner), m_Receiver (nullptr)
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{
}
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);
m_Owner.GetService ().post (std::bind (&DatagramDestination::SendMsg, this,
CreateDataMessage (buf, len + headerLen), remote));
}
void DatagramDestination::SendMsg (I2NPMessage * msg, const i2p::data::LeaseSet& remote)
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{
auto outboundTunnel = m_Owner.GetTunnelPool ()->GetNextOutboundTunnel ();
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auto leases = remote.GetNonExpiredLeases ();
if (!leases.empty () && outboundTunnel)
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{
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);
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msgs.push_back (i2p::tunnel::TunnelMessageBlock
{
i2p::tunnel::eDeliveryTypeTunnel,
leases[i].tunnelGateway, leases[i].tunnelID,
garlic
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});
outboundTunnel->SendTunnelDataMsg (msgs);
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}
else
{
if (outboundTunnel)
LogPrint (eLogWarning, "Failed to send datagram. All leases expired");
else
LogPrint (eLogWarning, "Failed to send datagram. No outbound tunnels");
DeleteI2NPMessage (msg);
}
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}
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)
verified = CryptoPP::SHA256().VerifyDigest (signature, buf + headerLen, len - headerLen);
else
verified = identity.Verify (buf + headerLen, len - headerLen, signature);
if (verified)
{
if (m_Receiver != nullptr)
m_Receiver (identity, buf + headerLen, len -headerLen);
else
LogPrint (eLogWarning, "Receiver for datagram is not set");
}
else
LogPrint (eLogWarning, "Datagram signature verification failed");
}
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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);
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}
else
LogPrint ("Received datagram size ", uncompressedLen, " exceeds max size");
}
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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;
}
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}
}