I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <cryptopp/dh.h>
#include <boost/bind.hpp>
#include "Log.h"
#include "CryptoConst.h"
#include "RouterContext.h"
#include "I2NPProtocol.h"
#include "NetDb.h"
#include "Transports.h"
using namespace i2p::data;
namespace i2p
{
namespace transport
{
DHKeysPairSupplier::DHKeysPairSupplier (int size):
m_QueueSize (size), m_IsRunning (false), m_Thread (nullptr)
{
}
DHKeysPairSupplier::~DHKeysPairSupplier ()
{
Stop ();
}
void DHKeysPairSupplier::Start ()
{
m_IsRunning = true;
m_Thread = new std::thread (std::bind (&DHKeysPairSupplier::Run, this));
}
void DHKeysPairSupplier::Stop ()
{
m_IsRunning = false;
m_Acquired.notify_one ();
if (m_Thread)
{
m_Thread->join ();
delete m_Thread;
m_Thread = 0;
}
}
void DHKeysPairSupplier::Run ()
{
while (m_IsRunning)
{
int num;
while ((num = m_QueueSize - m_Queue.size ()) > 0)
CreateDHKeysPairs (num);
std::unique_lock<std::mutex> l(m_AcquiredMutex);
m_Acquired.wait (l); // wait for element gets aquired
}
}
void DHKeysPairSupplier::CreateDHKeysPairs (int num)
{
if (num > 0)
{
CryptoPP::DH dh (i2p::crypto::elgp, i2p::crypto::elgg);
for (int i = 0; i < num; i++)
{
i2p::transport::DHKeysPair * pair = new i2p::transport::DHKeysPair ();
dh.GenerateKeyPair(m_Rnd, pair->privateKey, pair->publicKey);
std::unique_lock<std::mutex> l(m_AcquiredMutex);
m_Queue.push (pair);
}
}
}
DHKeysPair * DHKeysPairSupplier::Acquire ()
{
if (!m_Queue.empty ())
{
std::unique_lock<std::mutex> l(m_AcquiredMutex);
auto pair = m_Queue.front ();
m_Queue.pop ();
m_Acquired.notify_one ();
return pair;
}
else // queue is empty, create new
{
DHKeysPair * pair = new DHKeysPair ();
CryptoPP::DH dh (i2p::crypto::elgp, i2p::crypto::elgg);
dh.GenerateKeyPair(m_Rnd, pair->privateKey, pair->publicKey);
return pair;
}
}
void DHKeysPairSupplier::Return (DHKeysPair * pair)
{
std::unique_lock<std::mutex> l(m_AcquiredMutex);
m_Queue.push (pair);
}
Transports transports;
Transports::Transports ():
m_Thread (nullptr), m_Work (m_Service), m_NTCPAcceptor (nullptr),
m_SSUServer (nullptr), m_DHKeysPairSupplier (5) // 5 pre-generated keys
{
}
Transports::~Transports ()
{
Stop ();
}
void Transports::Start ()
{
m_DHKeysPairSupplier.Start ();
m_IsRunning = true;
m_Thread = new std::thread (std::bind (&Transports::Run, this));
// create acceptors
auto addresses = context.GetRouterInfo ().GetAddresses ();
for (auto& address : addresses)
{
if (address.transportStyle == RouterInfo::eTransportNTCP)
{
m_NTCPAcceptor = new boost::asio::ip::tcp::acceptor (m_Service,
boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), address.port));
LogPrint ("Start listening TCP port ", address.port);
auto conn = new NTCPServerConnection (m_Service);
m_NTCPAcceptor->async_accept(conn->GetSocket (), boost::bind (&Transports::HandleAccept, this,
conn, boost::asio::placeholders::error));
}
else if (address.transportStyle == RouterInfo::eTransportSSU)
{
if (!m_SSUServer)
{
m_SSUServer = new SSUServer (address.port);
LogPrint ("Start listening UDP port ", address.port);
m_SSUServer->Start ();
DetectExternalIP ();
}
else
LogPrint ("SSU server already exists");
}
}
}
void Transports::Stop ()
{
if (m_SSUServer)
{
m_SSUServer->Stop ();
delete m_SSUServer;
m_SSUServer = nullptr;
}
for (auto session: m_NTCPSessions)
delete session.second;
m_NTCPSessions.clear ();
delete m_NTCPAcceptor;
m_NTCPAcceptor = nullptr;
m_DHKeysPairSupplier.Stop ();
m_IsRunning = false;
m_Service.stop ();
if (m_Thread)
{
m_Thread->join ();
delete m_Thread;
m_Thread = nullptr;
}
}
void Transports::Run ()
{
while (m_IsRunning)
{
try
{
m_Service.run ();
}
catch (std::exception& ex)
{
LogPrint ("Transports: ", ex.what ());
}
}
}
void Transports::AddNTCPSession (NTCPSession * session)
{
if (session)
m_NTCPSessions[session->GetRemoteIdentity ().GetIdentHash ()] = session;
}
void Transports::RemoveNTCPSession (NTCPSession * session)
{
if (session)
m_NTCPSessions.erase (session->GetRemoteIdentity ().GetIdentHash ());
}
void Transports::HandleAccept (NTCPServerConnection * conn, const boost::system::error_code& error)
{
if (!error)
{
LogPrint ("Connected from ", conn->GetSocket ().remote_endpoint().address ().to_string ());
conn->ServerLogin ();
}
else
delete conn;
if (error != boost::asio::error::operation_aborted)
{
conn = new NTCPServerConnection (m_Service);
m_NTCPAcceptor->async_accept(conn->GetSocket (), boost::bind (&Transports::HandleAccept, this,
conn, boost::asio::placeholders::error));
}
}
NTCPSession * Transports::GetNextNTCPSession ()
{
for (auto session: m_NTCPSessions)
if (session.second->IsEstablished ())
return session.second;
return 0;
}
NTCPSession * Transports::FindNTCPSession (const i2p::data::IdentHash& ident)
{
auto it = m_NTCPSessions.find (ident);
if (it != m_NTCPSessions.end ())
return it->second;
return 0;
}
void Transports::SendMessage (const i2p::data::IdentHash& ident, i2p::I2NPMessage * msg)
{
if (ident == i2p::context.GetRouterInfo ().GetIdentHash ())
// we send it to ourself
i2p::HandleI2NPMessage (msg);
else
m_Service.post (boost::bind (&Transports::PostMessage, this, ident, msg));
}
void Transports::PostMessage (const i2p::data::IdentHash& ident, i2p::I2NPMessage * msg)
{
auto session = FindNTCPSession (ident);
if (session)
session->SendI2NPMessage (msg);
else
{
RouterInfo * r = netdb.FindRouter (ident);
if (r)
{
auto ssuSession = m_SSUServer ? m_SSUServer->FindSession (r) : nullptr;
if (ssuSession)
ssuSession->SendI2NPMessage (msg);
else
{
// existing session not found. create new
// try NTCP first if message size < 16K
auto address = r->GetNTCPAddress ();
if (address && !r->UsesIntroducer () && !r->IsUnreachable () && msg->GetLength () < NTCP_MAX_MESSAGE_SIZE)
{
auto s = new NTCPClient (m_Service, address->host, address->port, *r);
AddNTCPSession (s);
s->SendI2NPMessage (msg);
}
else
{
// then SSU
auto s = m_SSUServer ? m_SSUServer->GetSession (r) : nullptr;
if (s)
s->SendI2NPMessage (msg);
else
{
LogPrint ("No NTCP and SSU addresses available");
DeleteI2NPMessage (msg);
}
}
}
}
else
{
LogPrint ("Router not found. Requested");
i2p::data::netdb.RequestDestination (ident);
auto resendTimer = new boost::asio::deadline_timer (m_Service);
resendTimer->expires_from_now (boost::posix_time::seconds(5)); // 5 seconds
resendTimer->async_wait (boost::bind (&Transports::HandleResendTimer,
this, boost::asio::placeholders::error, resendTimer, ident, msg));
}
}
}
void Transports::HandleResendTimer (const boost::system::error_code& ecode,
boost::asio::deadline_timer * timer, const i2p::data::IdentHash& ident, i2p::I2NPMessage * msg)
{
RouterInfo * r = netdb.FindRouter (ident);
if (r)
{
LogPrint ("Router found. Sending message");
PostMessage (ident, msg);
}
else
{
LogPrint ("Router not found. Failed to send message");
DeleteI2NPMessage (msg);
}
delete timer;
}
void Transports::CloseSession (const i2p::data::RouterInfo * router)
{
if (!router) return;
m_Service.post (boost::bind (&Transports::PostCloseSession, this, router));
}
void Transports::PostCloseSession (const i2p::data::RouterInfo * router)
{
auto ssuSession = m_SSUServer ? m_SSUServer->FindSession (router) : nullptr;
if (ssuSession) // try SSU first
{
m_SSUServer->DeleteSession (ssuSession);
LogPrint ("SSU session closed");
}
// TODO: delete NTCP
}
void Transports::DetectExternalIP ()
{
for (int i = 0; i < 5; i ++)
{
auto router = i2p::data::netdb.GetRandomRouter ();
if (router && router->IsSSU () && m_SSUServer)
m_SSUServer->GetSession (router, true); // peer test
}
}
DHKeysPair * Transports::GetNextDHKeysPair ()
{
return m_DHKeysPairSupplier.Acquire ();
}
void Transports::ReuseDHKeysPair (DHKeysPair * pair)
{
m_DHKeysPairSupplier.Return (pair);
}
}
}