I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <string.h>
#include <boost/bind.hpp>
#include "Log.h"
#include "Timestamp.h"
#include "RouterContext.h"
#include "SSU.h"
namespace i2p
{
namespace transport
{
SSUServer::SSUServer (int port): m_Thread (nullptr), m_ThreadV6 (nullptr), m_Work (m_Service),
m_WorkV6 (m_ServiceV6),m_Endpoint (boost::asio::ip::udp::v4 (), port),
m_EndpointV6 (boost::asio::ip::udp::v6 (), port), m_Socket (m_Service, m_Endpoint),
m_SocketV6 (m_ServiceV6), m_IntroducersUpdateTimer (m_Service)
{
m_Socket.set_option (boost::asio::socket_base::receive_buffer_size (65535));
m_Socket.set_option (boost::asio::socket_base::send_buffer_size (65535));
if (context.SupportsV6 ())
{
m_SocketV6.open (boost::asio::ip::udp::v6());
m_SocketV6.set_option (boost::asio::ip::v6_only (true));
m_SocketV6.set_option (boost::asio::socket_base::receive_buffer_size (65535));
m_SocketV6.set_option (boost::asio::socket_base::send_buffer_size (65535));
m_SocketV6.bind (m_EndpointV6);
}
}
SSUServer::~SSUServer ()
{
}
void SSUServer::Start ()
{
m_IsRunning = true;
m_Thread = new std::thread (std::bind (&SSUServer::Run, this));
m_Service.post (std::bind (&SSUServer::Receive, this));
if (context.SupportsV6 ())
{
m_ThreadV6 = new std::thread (std::bind (&SSUServer::RunV6, this));
m_ServiceV6.post (std::bind (&SSUServer::ReceiveV6, this));
}
if (i2p::context.IsUnreachable ())
ScheduleIntroducersUpdateTimer ();
}
void SSUServer::Stop ()
{
DeleteAllSessions ();
m_IsRunning = false;
m_Service.stop ();
m_Socket.close ();
m_ServiceV6.stop ();
m_SocketV6.close ();
if (m_Thread)
{
m_Thread->join ();
delete m_Thread;
m_Thread = nullptr;
}
if (m_ThreadV6)
{
m_ThreadV6->join ();
delete m_ThreadV6;
m_ThreadV6 = nullptr;
}
}
void SSUServer::Run ()
{
while (m_IsRunning)
{
try
{
m_Service.run ();
}
catch (std::exception& ex)
{
LogPrint (eLogError, "SSU server: ", ex.what ());
}
}
}
void SSUServer::RunV6 ()
{
while (m_IsRunning)
{
try
{
m_ServiceV6.run ();
}
catch (std::exception& ex)
{
LogPrint (eLogError, "SSU V6 server: ", ex.what ());
}
}
}
void SSUServer::AddRelay (uint32_t tag, const boost::asio::ip::udp::endpoint& relay)
{
m_Relays[tag] = relay;
}
std::shared_ptr<SSUSession> SSUServer::FindRelaySession (uint32_t tag)
{
auto it = m_Relays.find (tag);
if (it != m_Relays.end ())
return FindSession (it->second);
return nullptr;
}
void SSUServer::Send (const uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& to)
{
if (to.protocol () == boost::asio::ip::udp::v4())
m_Socket.send_to (boost::asio::buffer (buf, len), to);
else
m_SocketV6.send_to (boost::asio::buffer (buf, len), to);
}
void SSUServer::Receive ()
{
m_Socket.async_receive_from (boost::asio::buffer (m_ReceiveBuffer, SSU_MTU_V4), m_SenderEndpoint,
boost::bind (&SSUServer::HandleReceivedFrom, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
}
void SSUServer::ReceiveV6 ()
{
m_SocketV6.async_receive_from (boost::asio::buffer (m_ReceiveBufferV6, SSU_MTU_V6), m_SenderEndpointV6,
boost::bind (&SSUServer::HandleReceivedFromV6, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
}
void SSUServer::HandleReceivedFrom (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (!ecode)
{
HandleReceivedBuffer (m_SenderEndpoint, m_ReceiveBuffer, bytes_transferred);
Receive ();
}
else
LogPrint ("SSU receive error: ", ecode.message ());
}
void SSUServer::HandleReceivedFromV6 (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (!ecode)
{
HandleReceivedBuffer (m_SenderEndpointV6, m_ReceiveBufferV6, bytes_transferred);
ReceiveV6 ();
}
else
LogPrint ("SSU V6 receive error: ", ecode.message ());
}
void SSUServer::HandleReceivedBuffer (boost::asio::ip::udp::endpoint& from, uint8_t * buf, std::size_t bytes_transferred)
{
std::shared_ptr<SSUSession> session;
auto it = m_Sessions.find (from);
if (it != m_Sessions.end ())
session = it->second;
if (!session)
{
session = std::make_shared<SSUSession> (*this, from);
session->WaitForConnect ();
m_Sessions[from] = session;
LogPrint ("New SSU session from ", from.address ().to_string (), ":", from.port (), " created");
}
session->ProcessNextMessage (buf, bytes_transferred, from);
}
std::shared_ptr<SSUSession> SSUServer::FindSession (std::shared_ptr<const i2p::data::RouterInfo> router) const
{
if (!router) return nullptr;
auto address = router->GetSSUAddress (true); // v4 only
if (!address) return nullptr;
auto session = FindSession (boost::asio::ip::udp::endpoint (address->host, address->port));
if (session || !context.SupportsV6 ())
return session;
// try v6
address = router->GetSSUV6Address ();
if (!address) return nullptr;
return FindSession (boost::asio::ip::udp::endpoint (address->host, address->port));
}
std::shared_ptr<SSUSession> SSUServer::FindSession (const boost::asio::ip::udp::endpoint& e) const
{
auto it = m_Sessions.find (e);
if (it != m_Sessions.end ())
return it->second;
else
return nullptr;
}
std::shared_ptr<SSUSession> SSUServer::GetSession (std::shared_ptr<const i2p::data::RouterInfo> router, bool peerTest)
{
std::shared_ptr<SSUSession> session;
if (router)
{
auto address = router->GetSSUAddress (!context.SupportsV6 ());
if (address)
{
boost::asio::ip::udp::endpoint remoteEndpoint (address->host, address->port);
auto it = m_Sessions.find (remoteEndpoint);
if (it != m_Sessions.end ())
session = it->second;
else
{
// otherwise create new session
session = std::make_shared<SSUSession> (*this, remoteEndpoint, router, peerTest);
m_Sessions[remoteEndpoint] = session;
if (!router->UsesIntroducer ())
{
// connect directly
LogPrint ("Creating new SSU session to [", router->GetIdentHashAbbreviation (), "] ",
remoteEndpoint.address ().to_string (), ":", remoteEndpoint.port ());
session->Connect ();
}
else
{
// connect through introducer
int numIntroducers = address->introducers.size ();
if (numIntroducers > 0)
{
std::shared_ptr<SSUSession> introducerSession;
const i2p::data::RouterInfo::Introducer * introducer = nullptr;
// we might have a session to introducer already
for (int i = 0; i < numIntroducers; i++)
{
introducer = &(address->introducers[i]);
it = m_Sessions.find (boost::asio::ip::udp::endpoint (introducer->iHost, introducer->iPort));
if (it != m_Sessions.end ())
{
introducerSession = it->second;
break;
}
}
if (introducerSession) // session found
LogPrint ("Session to introducer already exists");
else // create new
{
LogPrint ("Creating new session to introducer");
introducer = &(address->introducers[0]); // TODO:
boost::asio::ip::udp::endpoint introducerEndpoint (introducer->iHost, introducer->iPort);
introducerSession = std::make_shared<SSUSession> (*this, introducerEndpoint, router);
m_Sessions[introducerEndpoint] = introducerSession;
}
// introduce
LogPrint ("Introduce new SSU session to [", router->GetIdentHashAbbreviation (),
"] through introducer ", introducer->iHost, ":", introducer->iPort);
session->WaitForIntroduction ();
if (i2p::context.GetRouterInfo ().UsesIntroducer ()) // if we are unreachable
Send (m_ReceiveBuffer, 0, remoteEndpoint); // send HolePunch
introducerSession->Introduce (introducer->iTag, introducer->iKey);
}
else
{
LogPrint (eLogWarning, "Can't connect to unreachable router. No introducers presented");
m_Sessions.erase (remoteEndpoint);
session.reset ();
}
}
}
}
else
LogPrint (eLogWarning, "Router ", router->GetIdentHashAbbreviation (), " doesn't have SSU address");
}
return session;
}
void SSUServer::DeleteSession (std::shared_ptr<SSUSession> session)
{
if (session)
{
session->Close ();
m_Sessions.erase (session->GetRemoteEndpoint ());
}
}
void SSUServer::DeleteAllSessions ()
{
for (auto it: m_Sessions)
it.second->Close ();
m_Sessions.clear ();
}
template<typename Filter>
std::shared_ptr<SSUSession> SSUServer::GetRandomSession (Filter filter)
{
std::vector<std::shared_ptr<SSUSession> > filteredSessions;
for (auto s :m_Sessions)
if (filter (s.second)) filteredSessions.push_back (s.second);
if (filteredSessions.size () > 0)
{
auto ind = i2p::context.GetRandomNumberGenerator ().GenerateWord32 (0, filteredSessions.size ()-1);
return filteredSessions[ind];
}
return nullptr;
}
std::shared_ptr<SSUSession> SSUServer::GetRandomEstablishedSession (std::shared_ptr<const SSUSession> excluded)
{
return GetRandomSession (
[excluded](std::shared_ptr<SSUSession> session)->bool
{
return session->GetState () == eSessionStateEstablished &&
session != excluded;
}
);
}
std::set<SSUSession *> SSUServer::FindIntroducers (int maxNumIntroducers)
{
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
std::set<SSUSession *> ret;
for (int i = 0; i < maxNumIntroducers; i++)
{
auto session = GetRandomSession (
[&ret, ts](std::shared_ptr<SSUSession> session)->bool
{
return session->GetRelayTag () && !ret.count (session.get ()) &&
session->GetState () == eSessionStateEstablished &&
ts < session->GetCreationTime () + SSU_TO_INTRODUCER_SESSION_DURATION;
}
);
if (session)
{
ret.insert (session.get ());
break;
}
}
return ret;
}
void SSUServer::ScheduleIntroducersUpdateTimer ()
{
m_IntroducersUpdateTimer.expires_from_now (boost::posix_time::seconds(SSU_KEEP_ALIVE_INTERVAL));
m_IntroducersUpdateTimer.async_wait (std::bind (&SSUServer::HandleIntroducersUpdateTimer,
this, std::placeholders::_1));
}
void SSUServer::HandleIntroducersUpdateTimer (const boost::system::error_code& ecode)
{
if (!ecode)
{
// timeout expired
std::list<boost::asio::ip::udp::endpoint> newList;
size_t numIntroducers = 0;
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
for (auto it :m_Introducers)
{
auto session = FindSession (it);
if (session && ts < session->GetCreationTime () + SSU_TO_INTRODUCER_SESSION_DURATION)
{
session->SendKeepAlive ();
newList.push_back (it);
numIntroducers++;
}
else
i2p::context.RemoveIntroducer (it);
}
if (numIntroducers < SSU_MAX_NUM_INTRODUCERS)
{
// create new
auto introducers = FindIntroducers (SSU_MAX_NUM_INTRODUCERS);
if (introducers.size () > 0)
{
for (auto it1: introducers)
{
auto router = it1->GetRemoteRouter ();
if (router && i2p::context.AddIntroducer (*router, it1->GetRelayTag ()))
{
newList.push_back (it1->GetRemoteEndpoint ());
if (newList.size () >= SSU_MAX_NUM_INTRODUCERS) break;
}
}
}
}
m_Introducers = newList;
ScheduleIntroducersUpdateTimer ();
}
}
}
}