I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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/*
* Copyright (c) 2013-2016, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/
#include <string.h>
#include <openssl/rand.h>
#include "I2PEndian.h"
#include "Log.h"
#include "Timestamp.h"
#include "LeaseSet.h"
#include "I2CP.h"
namespace i2p
{
namespace client
{
I2CPDestination::I2CPDestination (I2CPSession& owner, std::shared_ptr<const i2p::data::IdentityEx> identity, bool isPublic):
LeaseSetDestination (isPublic), m_Owner (owner), m_Identity (identity)
{
}
void I2CPDestination::SetEncryptionPrivateKey (const uint8_t * key)
{
memcpy (m_EncryptionPrivateKey, key, 256);
}
void I2CPDestination::CreateNewLeaseSet (std::vector<std::shared_ptr<i2p::tunnel::InboundTunnel> > tunnels)
{
i2p::data::LocalLeaseSet ls (m_Identity, m_EncryptionPrivateKey, tunnels); // we don't care about encryption key
m_LeaseSetExpirationTime = ls.GetExpirationTime ();
uint8_t * leases = ls.GetLeases ();
leases[-1] = tunnels.size ();
htobe16buf (leases - 3, m_Owner.GetSessionID ());
size_t l = 2/*sessionID*/ + 1/*num leases*/ + i2p::data::LEASE_SIZE*tunnels.size ();
m_Owner.SendI2CPMessage (I2CP_REQUEST_VARIABLE_LEASESET_MESSAGE, leases - 3, l);
}
void I2CPDestination::LeaseSetCreated (const uint8_t * buf, size_t len)
{
auto ls = new i2p::data::LocalLeaseSet (m_Identity, buf, len);
ls->SetExpirationTime (m_LeaseSetExpirationTime);
SetLeaseSet (ls);
}
void I2CPDestination::SendMsgTo (const uint8_t * payload, size_t len, const i2p::data::IdentHash& ident)
{
auto msg = NewI2NPMessage ();
uint8_t * buf = msg->GetPayload ();
htobe32buf (buf, len);
memcpy (buf + 4, payload, len);
msg->len += len + 4;
msg->FillI2NPMessageHeader (eI2NPData);
// TODO: send
}
I2CPSession::I2CPSession (I2CPServer& owner, std::shared_ptr<boost::asio::ip::tcp::socket> socket):
m_Owner (owner), m_Socket (socket),
m_NextMessage (nullptr), m_NextMessageLen (0), m_NextMessageOffset (0),
m_SessionID (0)
{
ReadProtocolByte ();
}
I2CPSession::~I2CPSession ()
{
delete[] m_NextMessage;
}
void I2CPSession::ReadProtocolByte ()
{
if (m_Socket)
{
auto s = shared_from_this ();
m_Socket->async_read_some (boost::asio::buffer (m_Buffer, 1),
[s](const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (!ecode && bytes_transferred > 0 && s->m_Buffer[0] == I2CP_PRTOCOL_BYTE)
s->Receive ();
else
s->Terminate ();
});
}
}
void I2CPSession::Receive ()
{
m_Socket->async_read_some (boost::asio::buffer (m_Buffer, I2CP_SESSION_BUFFER_SIZE),
std::bind (&I2CPSession::HandleReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
void I2CPSession::HandleReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (ecode)
Terminate ();
else
{
size_t offset = 0;
if (m_NextMessage)
{
if (m_NextMessageOffset + bytes_transferred <= m_NextMessageLen)
{
memcpy (m_NextMessage + m_NextMessageOffset, m_Buffer, bytes_transferred);
m_NextMessageOffset += bytes_transferred;
}
else
{
offset = m_NextMessageLen - m_NextMessageOffset;
memcpy (m_NextMessage + m_NextMessageOffset, m_Buffer, offset);
HandleNextMessage (m_NextMessage);
delete[] m_NextMessage;
}
}
while (offset < bytes_transferred)
{
auto msgLen = bufbe32toh (m_Buffer + offset + I2CP_HEADER_LENGTH_OFFSET) + I2CP_HEADER_SIZE;
if (msgLen <= bytes_transferred - offset)
{
HandleNextMessage (m_Buffer + offset);
offset += msgLen;
}
else
{
m_NextMessageLen = msgLen;
m_NextMessageOffset = bytes_transferred - offset;
m_NextMessage = new uint8_t[m_NextMessageLen];
memcpy (m_NextMessage, m_Buffer + offset, m_NextMessageOffset);
offset = bytes_transferred;
}
}
Receive ();
}
}
void I2CPSession::HandleNextMessage (const uint8_t * buf)
{
auto handler = m_Owner.GetMessagesHandlers ()[buf[I2CP_HEADER_TYPE_OFFSET]];
if (handler)
(this->*handler)(buf + I2CP_HEADER_SIZE, bufbe32toh (buf + I2CP_HEADER_LENGTH_OFFSET));
else
LogPrint (eLogError, "I2CP: Unknown I2CP messsage ", (int)buf[I2CP_HEADER_TYPE_OFFSET]);
}
void I2CPSession::Terminate ()
{
}
void I2CPSession::SendI2CPMessage (uint8_t type, const uint8_t * payload, size_t len)
{
auto l = len + I2CP_HEADER_SIZE;
uint8_t * buf = new uint8_t[l];
htobe32buf (buf + I2CP_HEADER_LENGTH_OFFSET, len);
buf[I2CP_HEADER_TYPE_OFFSET] = type;
memcpy (buf + I2CP_HEADER_SIZE, payload, len);
boost::asio::async_write (*m_Socket, boost::asio::buffer (buf, l), boost::asio::transfer_all (),
std::bind(&I2CPSession::HandleI2CPMessageSent, shared_from_this (),
std::placeholders::_1, std::placeholders::_2, buf));
}
void I2CPSession::HandleI2CPMessageSent (const boost::system::error_code& ecode, std::size_t bytes_transferred, const uint8_t * buf)
{
delete[] buf;
if (ecode && ecode != boost::asio::error::operation_aborted)
Terminate ();
}
std::string I2CPSession::ExtractString (const uint8_t * buf, size_t len)
{
uint8_t l = buf[0];
if (l > len) l = len;
return std::string ((const char *)buf, l);
}
size_t I2CPSession::PutString (uint8_t * buf, size_t len, const std::string& str)
{
auto l = str.length ();
if (l + 1 >= len) l = len - 1;
if (l > 255) l = 255; // 1 byte max
buf[0] = l;
memcpy (buf + 1, str.c_str (), l);
return l + 1;
}
void I2CPSession::GetDateMessageHandler (const uint8_t * buf, size_t len)
{
// get version
auto version = ExtractString (buf, len);
auto l = version.length () + 1 + 8;
uint8_t * payload = new uint8_t[l];
// set date
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
htobe64buf (payload, ts);
// echo vesrion back
PutString (payload + 8, l - 8, version);
SendI2CPMessage (I2CP_SET_DATE_MESSAGE, payload, l);
delete[] payload;
}
void I2CPSession::CreateSessionMessageHandler (const uint8_t * buf, size_t len)
{
auto identity = std::make_shared<i2p::data::IdentityEx>();
size_t offset = identity->FromBuffer (buf, len);
uint16_t optionsSize = bufbe16toh (buf + offset);
// TODO: extract options
offset += optionsSize;
offset += 8; // date
if (identity->Verify (buf, offset, buf + offset)) // signature
{
m_Destination = std::make_shared<I2CPDestination>(*this, identity, false);
RAND_bytes ((uint8_t *)&m_SessionID, 2);
SendSessionStatusMessage (1); // created
}
else
{
LogPrint (eLogError, "I2CP: create session signature verification falied");
SendSessionStatusMessage (3); // invalid
}
}
void I2CPSession::SendSessionStatusMessage (uint8_t status)
{
uint8_t buf[3];
htobe16buf (buf, m_SessionID);
buf[2] = status;
SendI2CPMessage (I2CP_SESSION_STATUS_MESSAGE, buf, 3);
}
void I2CPSession::CreateLeaseSetMessageHandler (const uint8_t * buf, size_t len)
{
uint16_t sessionID = bufbe16toh (buf);
if (sessionID == m_SessionID)
{
size_t offset = 2;
if (m_Destination)
{
m_Destination->SetEncryptionPrivateKey (buf + offset);
offset += 256;
m_Destination->LeaseSetCreated (buf + offset, len - offset);
}
}
else
LogPrint (eLogError, "I2CP: unexpected sessionID ", sessionID);
}
void I2CPSession::SendMessageMessageHandler (const uint8_t * buf, size_t len)
{
uint16_t sessionID = bufbe16toh (buf);
if (sessionID == m_SessionID)
{
size_t offset = 2;
if (m_Destination)
{
i2p::data::IdentityEx identity;
offset += identity.FromBuffer (buf + offset, len - offset);
m_Destination->SendMsgTo (buf + offset, len - offset, identity.GetIdentHash ());
}
}
else
LogPrint (eLogError, "I2CP: unexpected sessionID ", sessionID);
}
I2CPServer::I2CPServer (const std::string& interface, int port)
{
memset (m_MessagesHandlers, 0, sizeof (m_MessagesHandlers));
m_MessagesHandlers[I2CP_GET_DATE_MESSAGE] = &I2CPSession::GetDateMessageHandler;
m_MessagesHandlers[I2CP_CREATE_SESSION_MESSAGE] = &I2CPSession::CreateSessionMessageHandler;
m_MessagesHandlers[I2CP_CREATE_LEASESET_MESSAGE] = &I2CPSession::CreateLeaseSetMessageHandler;
m_MessagesHandlers[I2CP_SEND_MESSAGE_MESSAGE] = &I2CPSession::SendMessageMessageHandler;
}
}
}