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i2pd/libi2pd/SSU2.cpp

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/*
* Copyright (c) 2022-2024, 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 <random>
#include "Log.h"
#include "RouterContext.h"
#include "Transports.h"
#include "NetDb.hpp"
#include "Config.h"
#include "SSU2.h"
namespace i2p
{
namespace transport
{
SSU2Server::SSU2Server ():
RunnableServiceWithWork ("SSU2"), m_ReceiveService ("SSU2r"),
m_SocketV4 (m_ReceiveService.GetService ()), m_SocketV6 (m_ReceiveService.GetService ()),
m_AddressV4 (boost::asio::ip::address_v4()), m_AddressV6 (boost::asio::ip::address_v6()),
m_TerminationTimer (GetService ()), m_CleanupTimer (GetService ()), m_ResendTimer (GetService ()),
m_IntroducersUpdateTimer (GetService ()), m_IntroducersUpdateTimerV6 (GetService ()),
m_IsPublished (true), m_IsSyncClockFromPeers (true), m_PendingTimeOffset (0),
m_Rng(i2p::util::GetMonotonicMicroseconds ()%1000000LL), m_IsThroughProxy (false)
{
}
void SSU2Server::Start ()
{
if (!IsRunning ())
{
StartIOService ();
i2p::config::GetOption ("ssu2.published", m_IsPublished);
i2p::config::GetOption("nettime.frompeers", m_IsSyncClockFromPeers);
bool found = false;
auto addresses = i2p::context.GetRouterInfo ().GetAddresses ();
if (!addresses) return;
for (const auto& address: *addresses)
{
if (!address) continue;
if (address->transportStyle == i2p::data::RouterInfo::eTransportSSU2)
{
if (m_IsThroughProxy)
{
found = true;
if (address->IsV6 ())
{
uint16_t mtu; i2p::config::GetOption ("ssu2.mtu6", mtu);
if (!mtu || mtu > SSU2_MAX_PACKET_SIZE - SOCKS5_UDP_IPV6_REQUEST_HEADER_SIZE)
mtu = SSU2_MAX_PACKET_SIZE - SOCKS5_UDP_IPV6_REQUEST_HEADER_SIZE;
i2p::context.SetMTU (mtu, false);
}
else
{
uint16_t mtu; i2p::config::GetOption ("ssu2.mtu4", mtu);
if (!mtu || mtu > SSU2_MAX_PACKET_SIZE - SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE)
mtu = SSU2_MAX_PACKET_SIZE - SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE;
i2p::context.SetMTU (mtu, true);
}
continue; // we don't need port for proxy
}
auto port = address->port;
if (!port)
{
uint16_t ssu2Port; i2p::config::GetOption ("ssu2.port", ssu2Port);
if (ssu2Port) port = ssu2Port;
else
{
uint16_t p; i2p::config::GetOption ("port", p);
if (p) port = p;
}
}
if (port)
{
if (address->IsV4 ())
{
found = true;
LogPrint (eLogDebug, "SSU2: Opening IPv4 socket at Start");
OpenSocket (boost::asio::ip::udp::endpoint (m_AddressV4, port));
m_ReceiveService.GetService ().post(
[this]()
{
Receive (m_SocketV4);
});
ScheduleIntroducersUpdateTimer (); // wait for 30 seconds and decide if we need introducers
}
if (address->IsV6 ())
{
found = true;
LogPrint (eLogDebug, "SSU2: Opening IPv6 socket at Start");
OpenSocket (boost::asio::ip::udp::endpoint (m_AddressV6, port));
m_ReceiveService.GetService ().post(
[this]()
{
Receive (m_SocketV6);
});
ScheduleIntroducersUpdateTimerV6 (); // wait for 30 seconds and decide if we need introducers
}
}
else
LogPrint (eLogCritical, "SSU2: Can't start server because port not specified");
}
}
if (found)
{
if (m_IsThroughProxy)
ConnectToProxy ();
m_ReceiveService.Start ();
}
ScheduleTermination ();
ScheduleCleanup ();
ScheduleResend (false);
}
}
void SSU2Server::Stop ()
{
if (IsRunning ())
{
m_TerminationTimer.cancel ();
m_CleanupTimer.cancel ();
m_ResendTimer.cancel ();
m_IntroducersUpdateTimer.cancel ();
m_IntroducersUpdateTimerV6.cancel ();
}
auto sessions = m_Sessions;
for (auto& it: sessions)
{
it.second->RequestTermination (eSSU2TerminationReasonRouterShutdown);
it.second->Done ();
}
if (context.SupportsV4 () || context.SupportsV6 ())
m_ReceiveService.Stop ();
m_SocketV4.close ();
m_SocketV6.close ();
if (m_UDPAssociateSocket)
{
m_UDPAssociateSocket->close ();
m_UDPAssociateSocket.reset (nullptr);
}
StopIOService ();
m_Sessions.clear ();
m_SessionsByRouterHash.clear ();
m_PendingOutgoingSessions.clear ();
m_Relays.clear ();
m_PeerTests.clear ();
m_Introducers.clear ();
m_IntroducersV6.clear ();
m_ConnectedRecently.clear ();
m_RequestedPeerTests.clear ();
m_PacketsPool.ReleaseMt (m_ReceivedPacketsQueue);
m_ReceivedPacketsQueue.clear ();
}
void SSU2Server::SetLocalAddress (const boost::asio::ip::address& localAddress)
{
if (localAddress.is_unspecified ()) return;
if (localAddress.is_v4 ())
{
m_AddressV4 = localAddress;
uint16_t mtu; i2p::config::GetOption ("ssu2.mtu4", mtu);
if (!mtu) mtu = i2p::util::net::GetMTU (localAddress);
if (mtu < (int)SSU2_MIN_PACKET_SIZE) mtu = SSU2_MIN_PACKET_SIZE;
if (mtu > (int)SSU2_MAX_PACKET_SIZE) mtu = SSU2_MAX_PACKET_SIZE;
i2p::context.SetMTU (mtu, true);
}
else if (localAddress.is_v6 ())
{
m_AddressV6 = localAddress;
uint16_t mtu; i2p::config::GetOption ("ssu2.mtu6", mtu);
if (!mtu)
{
int maxMTU = i2p::util::net::GetMaxMTU (localAddress.to_v6 ());
mtu = i2p::util::net::GetMTU (localAddress);
if (mtu > maxMTU) mtu = maxMTU;
}
else
if (mtu > (int)SSU2_MAX_PACKET_SIZE) mtu = SSU2_MAX_PACKET_SIZE;
if (mtu < (int)SSU2_MIN_PACKET_SIZE) mtu = SSU2_MIN_PACKET_SIZE;
i2p::context.SetMTU (mtu, false);
}
}
bool SSU2Server::IsSupported (const boost::asio::ip::address& addr) const
{
if (m_IsThroughProxy)
return m_SocketV4.is_open ();
if (addr.is_v4 ())
{
if (m_SocketV4.is_open ())
return true;
}
else if (addr.is_v6 ())
{
if (m_SocketV6.is_open ())
return true;
}
return false;
}
uint16_t SSU2Server::GetPort (bool v4) const
{
boost::system::error_code ec;
boost::asio::ip::udp::endpoint ep = (v4 || m_IsThroughProxy) ? m_SocketV4.local_endpoint (ec) : m_SocketV6.local_endpoint (ec);
if (ec) return 0;
return ep.port ();
}
bool SSU2Server::IsConnectedRecently (const boost::asio::ip::udp::endpoint& ep, bool max)
{
if (!ep.port () || ep.address ().is_unspecified ()) return false;
std::lock_guard<std::mutex> l(m_ConnectedRecentlyMutex);
auto it = m_ConnectedRecently.find (ep);
if (it != m_ConnectedRecently.end ())
{
if (i2p::util::GetSecondsSinceEpoch () <= it->second + (max ? SSU2_MAX_HOLE_PUNCH_EXPIRATION : SSU2_MIN_HOLE_PUNCH_EXPIRATION))
return true;
else if (max)
m_ConnectedRecently.erase (it);
}
return false;
}
void SSU2Server::AddConnectedRecently (const boost::asio::ip::udp::endpoint& ep, uint64_t ts)
{
if (!ep.port () || ep.address ().is_unspecified () ||
i2p::util::GetSecondsSinceEpoch () > ts + SSU2_MAX_HOLE_PUNCH_EXPIRATION) return;
std::lock_guard<std::mutex> l(m_ConnectedRecentlyMutex);
auto [it, added] = m_ConnectedRecently.try_emplace (ep, ts);
if (!added && ts > it->second)
it->second = ts; // renew timestamp of existing endpoint
}
void SSU2Server::AdjustTimeOffset (int64_t offset, std::shared_ptr<const i2p::data::IdentityEx> from)
{
if (offset)
{
if (m_PendingTimeOffset) // one more
{
if (m_PendingTimeOffsetFrom && from &&
m_PendingTimeOffsetFrom->GetIdentHash ().GetLL()[0] != from->GetIdentHash ().GetLL()[0]) // from different routers
{
if (std::abs (m_PendingTimeOffset - offset) < SSU2_CLOCK_SKEW)
{
offset = (m_PendingTimeOffset + offset)/2; // average
LogPrint (eLogWarning, "SSU2: Clock adjusted by ", offset, " seconds");
i2p::util::AdjustTimeOffset (offset);
}
else
LogPrint (eLogWarning, "SSU2: Time offsets are too different. Clock not adjusted");
m_PendingTimeOffset = 0;
m_PendingTimeOffsetFrom = nullptr;
}
else
LogPrint (eLogWarning, "SSU2: Time offsets from same router. Clock not adjusted");
}
else
{
m_PendingTimeOffset = offset; // first
m_PendingTimeOffsetFrom = from;
}
}
else
{
m_PendingTimeOffset = 0; // reset
m_PendingTimeOffsetFrom = nullptr;
}
}
boost::asio::ip::udp::socket& SSU2Server::OpenSocket (const boost::asio::ip::udp::endpoint& localEndpoint)
{
boost::asio::ip::udp::socket& socket = localEndpoint.address ().is_v6 () ? m_SocketV6 : m_SocketV4;
try
{
if (socket.is_open ())
socket.close ();
socket.open (localEndpoint.protocol ());
if (localEndpoint.address ().is_v6 ())
socket.set_option (boost::asio::ip::v6_only (true));
uint64_t bufferSize = i2p::context.GetBandwidthLimit() * 1024 / 5; // max lag = 200ms
bufferSize = std::max(SSU2_SOCKET_MIN_BUFFER_SIZE, std::min(bufferSize, SSU2_SOCKET_MAX_BUFFER_SIZE));
boost::asio::socket_base::receive_buffer_size receiveBufferSizeSet (bufferSize);
boost::asio::socket_base::send_buffer_size sendBufferSizeSet (bufferSize);
socket.set_option (receiveBufferSizeSet);
socket.set_option (sendBufferSizeSet);
boost::asio::socket_base::receive_buffer_size receiveBufferSizeGet;
boost::asio::socket_base::send_buffer_size sendBufferSizeGet;
socket.get_option (receiveBufferSizeGet);
socket.get_option (sendBufferSizeGet);
if (receiveBufferSizeGet.value () != receiveBufferSizeSet.value () ||
sendBufferSizeGet.value () != sendBufferSizeSet.value ())
{
LogPrint (eLogWarning, "SSU2: Socket receive buffer size: requested = ",
receiveBufferSizeSet.value (), ", got = ", receiveBufferSizeGet.value ());
LogPrint (eLogWarning, "SSU2: Socket send buffer size: requested = ",
sendBufferSizeSet.value (), ", got = ", sendBufferSizeGet.value ());
}
else
{
LogPrint (eLogInfo, "SSU2: Socket receive buffer size: ", receiveBufferSizeGet.value ());
LogPrint (eLogInfo, "SSU2: Socket send buffer size: ", sendBufferSizeGet.value ());
}
socket.non_blocking (true);
}
catch (std::exception& ex )
{
LogPrint (eLogCritical, "SSU2: Failed to open socket on ", localEndpoint.address (), ": ", ex.what());
ThrowFatal ("Unable to start SSU2 transport on ", localEndpoint.address (), ": ", ex.what ());
return socket;
}
try
{
socket.bind (localEndpoint);
LogPrint (eLogInfo, "SSU2: Start listening on ", localEndpoint);
}
catch (std::exception& ex )
{
LogPrint (eLogWarning, "SSU2: Failed to bind to ", localEndpoint, ": ", ex.what(), ". Actual endpoint is ", socket.local_endpoint ());
// we can continue without binding being firewalled
}
return socket;
}
void SSU2Server::Receive (boost::asio::ip::udp::socket& socket)
{
Packet * packet = m_PacketsPool.AcquireMt ();
socket.async_receive_from (boost::asio::buffer (packet->buf, SSU2_MAX_PACKET_SIZE), packet->from,
std::bind (&SSU2Server::HandleReceivedFrom, this, std::placeholders::_1, std::placeholders::_2, packet, std::ref (socket)));
}
void SSU2Server::HandleReceivedFrom (const boost::system::error_code& ecode, size_t bytes_transferred,
Packet * packet, boost::asio::ip::udp::socket& socket)
{
if (!ecode
|| ecode == boost::asio::error::connection_refused
|| ecode == boost::asio::error::connection_reset
|| ecode == boost::asio::error::network_reset
|| ecode == boost::asio::error::network_unreachable
|| ecode == boost::asio::error::host_unreachable
#ifdef _WIN32 // windows can throw WinAPI error, which is not handled by ASIO
|| ecode.value() == boost::winapi::ERROR_CONNECTION_REFUSED_
|| ecode.value() == boost::winapi::WSAENETRESET_ // 10052
|| ecode.value() == boost::winapi::ERROR_NETWORK_UNREACHABLE_
|| ecode.value() == boost::winapi::ERROR_HOST_UNREACHABLE_
#endif
)
// just try continue reading when received ICMP response otherwise socket can crash,
// but better to find out which host were sent it and mark that router as unreachable
{
i2p::transport::transports.UpdateReceivedBytes (bytes_transferred);
if (bytes_transferred < SSU2_MIN_RECEIVED_PACKET_SIZE)
{
// drop too short packets
m_PacketsPool.ReleaseMt (packet);
Receive (socket);
return;
}
packet->len = bytes_transferred;
boost::system::error_code ec;
size_t moreBytes = socket.available (ec);
if (!ec && moreBytes)
{
std::list<Packet *> packets;
packets.push_back (packet);
while (moreBytes && packets.size () < SSU2_MAX_NUM_PACKETS_PER_BATCH)
{
packet = m_PacketsPool.AcquireMt ();
packet->len = socket.receive_from (boost::asio::buffer (packet->buf, SSU2_MAX_PACKET_SIZE), packet->from, 0, ec);
if (!ec)
{
i2p::transport::transports.UpdateReceivedBytes (packet->len);
if (packet->len >= SSU2_MIN_RECEIVED_PACKET_SIZE)
packets.push_back (packet);
else // drop too short packets
m_PacketsPool.ReleaseMt (packet);
moreBytes = socket.available(ec);
if (ec) break;
}
else
{
LogPrint (eLogError, "SSU2: receive_from error: code ", ec.value(), ": ", ec.message ());
m_PacketsPool.ReleaseMt (packet);
break;
}
}
InsertToReceivedPacketsQueue (packets);
}
else
InsertToReceivedPacketsQueue (packet);
Receive (socket);
}
else
{
m_PacketsPool.ReleaseMt (packet);
if (ecode != boost::asio::error::operation_aborted)
{
LogPrint (eLogError, "SSU2: Receive error: code ", ecode.value(), ": ", ecode.message ());
if (m_IsThroughProxy)
{
m_UDPAssociateSocket.reset (nullptr);
m_ProxyRelayEndpoint.reset (nullptr);
m_SocketV4.close ();
ConnectToProxy ();
}
else
{
auto ep = socket.local_endpoint ();
LogPrint (eLogCritical, "SSU2: Reopening socket in HandleReceivedFrom: code ", ecode.value(), ": ", ecode.message ());
OpenSocket (ep);
Receive (socket);
}
}
}
}
void SSU2Server::HandleReceivedPackets (std::list<Packet *>&& packets)
{
if (packets.empty ()) return;
if (m_IsThroughProxy)
for (auto it: packets)
ProcessNextPacketFromProxy (it->buf, it->len);
else
for (auto it: packets)
ProcessNextPacket (it->buf, it->len, it->from);
m_PacketsPool.ReleaseMt (packets);
if (m_LastSession && m_LastSession->GetState () != eSSU2SessionStateTerminated)
m_LastSession->FlushData ();
}
void SSU2Server::InsertToReceivedPacketsQueue (Packet * packet)
{
if (!packet) return;
bool empty = false;
{
std::lock_guard<std::mutex> l(m_ReceivedPacketsQueueMutex);
empty = m_ReceivedPacketsQueue.empty ();
m_ReceivedPacketsQueue.push_back (packet);
}
if (empty)
GetService ().post([this]() { HandleReceivedPacketsQueue (); });
}
void SSU2Server::InsertToReceivedPacketsQueue (std::list<Packet *>& packets)
{
if (packets.empty ()) return;
bool empty = false;
{
std::lock_guard<std::mutex> l(m_ReceivedPacketsQueueMutex);
empty = m_ReceivedPacketsQueue.empty ();
m_ReceivedPacketsQueue.splice (m_ReceivedPacketsQueue.end (), packets);
}
if (empty)
GetService ().post([this]() { HandleReceivedPacketsQueue (); });
}
void SSU2Server::HandleReceivedPacketsQueue ()
{
std::list<Packet *> receivedPackets;
{
std::lock_guard<std::mutex> l(m_ReceivedPacketsQueueMutex);
m_ReceivedPacketsQueue.swap (receivedPackets);
}
HandleReceivedPackets (std::move (receivedPackets));
}
bool SSU2Server::AddSession (std::shared_ptr<SSU2Session> session)
{
if (session)
{
if (m_Sessions.emplace (session->GetConnID (), session).second)
{
if (session->GetState () != eSSU2SessionStatePeerTest)
AddSessionByRouterHash (session);
return true;
}
}
return false;
}
void SSU2Server::RemoveSession (uint64_t connID)
{
auto it = m_Sessions.find (connID);
if (it != m_Sessions.end ())
{
if (it->second->GetState () != eSSU2SessionStatePeerTest)
{
auto ident = it->second->GetRemoteIdentity ();
if (ident)
{
std::lock_guard<std::mutex> l(m_SessionsByRouterHashMutex);
auto it1 = m_SessionsByRouterHash.find (ident->GetIdentHash ());
if (it1 != m_SessionsByRouterHash.end () && it->second == it1->second.lock ())
m_SessionsByRouterHash.erase (it1);
}
}
if (m_LastSession == it->second)
m_LastSession = nullptr;
m_Sessions.erase (it);
}
}
void SSU2Server::RequestRemoveSession (uint64_t connID)
{
GetService ().post ([connID, this]() { RemoveSession (connID); });
}
void SSU2Server::AddSessionByRouterHash (std::shared_ptr<SSU2Session> session)
{
if (session)
{
auto ident = session->GetRemoteIdentity ();
if (ident)
{
std::shared_ptr<SSU2Session> oldSession;
{
std::lock_guard<std::mutex> l(m_SessionsByRouterHashMutex);
auto ret = m_SessionsByRouterHash.emplace (ident->GetIdentHash (), session);
if (!ret.second)
{
oldSession = ret.first->second.lock ();
// update session
ret.first->second = session;
}
}
if (oldSession && oldSession != session)
{
// session already exists
LogPrint (eLogWarning, "SSU2: Session to ", ident->GetIdentHash ().ToBase64 (), " already exists");
// move unsent msgs to new session
oldSession->MoveSendQueue (session);
// terminate existing
GetService ().post (std::bind (&SSU2Session::RequestTermination, oldSession, eSSU2TerminationReasonReplacedByNewSession));
}
}
}
}
bool SSU2Server::AddPendingOutgoingSession (std::shared_ptr<SSU2Session> session)
{
if (!session) return false;
std::lock_guard<std::mutex> l(m_PendingOutgoingSessionsMutex);
return m_PendingOutgoingSessions.emplace (session->GetRemoteEndpoint (), session).second;
}
std::shared_ptr<SSU2Session> SSU2Server::FindSession (const i2p::data::IdentHash& ident)
{
std::lock_guard<std::mutex> l(m_SessionsByRouterHashMutex);
auto it = m_SessionsByRouterHash.find (ident);
if (it != m_SessionsByRouterHash.end ())
{
if (!it->second.expired ())
{
auto s = it->second.lock ();
if (s && s->GetState () != eSSU2SessionStateTerminated)
return s;
}
m_SessionsByRouterHash.erase (it);
}
return nullptr;
}
std::shared_ptr<SSU2Session> SSU2Server::FindPendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep) const
{
std::lock_guard<std::mutex> l(m_PendingOutgoingSessionsMutex);
auto it = m_PendingOutgoingSessions.find (ep);
if (it != m_PendingOutgoingSessions.end ())
return it->second;
return nullptr;
}
void SSU2Server::RemovePendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep)
{
std::lock_guard<std::mutex> l(m_PendingOutgoingSessionsMutex);
m_PendingOutgoingSessions.erase (ep);
}
std::shared_ptr<SSU2Session> SSU2Server::GetRandomPeerTestSession (
i2p::data::RouterInfo::CompatibleTransports remoteTransports, const i2p::data::IdentHash& excluded)
{
if (m_Sessions.empty ()) return nullptr;
int ind = m_Rng () % m_Sessions.size ();
auto it = m_Sessions.begin ();
std::advance (it, ind);
while (it != m_Sessions.end ())
{
if (it->second->IsEstablished () && (it->second->GetRemotePeerTestTransports () & remoteTransports) &&
it->second->GetRemoteIdentity ()->GetIdentHash () != excluded)
return it->second;
it++;
}
// not found, try from beginning
it = m_Sessions.begin ();
while (it != m_Sessions.end () && ind)
{
if (it->second->IsEstablished () && (it->second->GetRemotePeerTestTransports () & remoteTransports) &&
it->second->GetRemoteIdentity ()->GetIdentHash () != excluded)
return it->second;
it++; ind--;
}
return nullptr;
}
void SSU2Server::AddRelay (uint32_t tag, std::shared_ptr<SSU2Session> relay)
{
m_Relays.emplace (tag, relay);
}
void SSU2Server::RemoveRelay (uint32_t tag)
{
m_Relays.erase (tag);
}
std::shared_ptr<SSU2Session> SSU2Server::FindRelaySession (uint32_t tag)
{
auto it = m_Relays.find (tag);
if (it != m_Relays.end ())
{
if (!it->second.expired ())
{
auto s = it->second.lock ();
if (s && s->IsEstablished ())
return s;
}
m_Relays.erase (it);
}
return nullptr;
}
bool SSU2Server::AddPeerTest (uint32_t nonce, std::shared_ptr<SSU2Session> aliceSession, uint64_t ts)
{
return m_PeerTests.emplace (nonce, std::pair{ aliceSession, ts }).second;
}
std::shared_ptr<SSU2Session> SSU2Server::GetPeerTest (uint32_t nonce)
{
auto it = m_PeerTests.find (nonce);
if (it != m_PeerTests.end ())
{
auto s = it->second.first.lock ();
m_PeerTests.erase (it);
return s;
}
return nullptr;
}
bool SSU2Server::AddRequestedPeerTest (uint32_t nonce, std::shared_ptr<SSU2PeerTestSession> session, uint64_t ts)
{
return m_RequestedPeerTests.emplace (nonce, std::pair{ session, ts }).second;
}
std::shared_ptr<SSU2PeerTestSession> SSU2Server::GetRequestedPeerTest (uint32_t nonce)
{
auto it = m_RequestedPeerTests.find (nonce);
if (it != m_RequestedPeerTests.end ())
{
auto s = it->second.first.lock ();
m_RequestedPeerTests.erase (it);
return s;
}
return nullptr;
}
void SSU2Server::ProcessNextPacket (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
{
if (len < 24) return;
uint64_t connID;
memcpy (&connID, buf, 8);
connID ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 24));
if (!m_LastSession || m_LastSession->GetConnID () != connID)
{
if (m_LastSession) m_LastSession->FlushData ();
auto it = m_Sessions.find (connID);
if (it != m_Sessions.end ())
m_LastSession = it->second;
else
m_LastSession = nullptr;
}
if (m_LastSession)
{
switch (m_LastSession->GetState ())
{
case eSSU2SessionStateEstablished:
case eSSU2SessionStateSessionConfirmedSent:
m_LastSession->ProcessData (buf, len, senderEndpoint);
break;
case eSSU2SessionStateSessionCreatedSent:
if (!m_LastSession->ProcessSessionConfirmed (buf, len))
{
m_LastSession->Done ();
m_LastSession = nullptr;
}
break;
case eSSU2SessionStateIntroduced:
if (m_LastSession->GetRemoteEndpoint ().address ().is_unspecified ())
m_LastSession->SetRemoteEndpoint (senderEndpoint);
if (m_LastSession->GetRemoteEndpoint ().address () == senderEndpoint.address ()) // port might be different
m_LastSession->ProcessHolePunch (buf, len);
else
{
LogPrint (eLogWarning, "SSU2: HolePunch address ", senderEndpoint.address (),
" doesn't match RelayResponse ", m_LastSession->GetRemoteEndpoint ().address ());
m_LastSession->Done ();
m_LastSession = nullptr;
}
break;
case eSSU2SessionStatePeerTest:
m_LastSession->SetRemoteEndpoint (senderEndpoint);
m_LastSession->ProcessPeerTest (buf, len);
break;
case eSSU2SessionStateHolePunch:
m_LastSession->ProcessFirstIncomingMessage (connID, buf, len); // SessionRequest
break;
case eSSU2SessionStateClosing:
m_LastSession->ProcessData (buf, len, senderEndpoint); // we might receive termintaion block
if (m_LastSession && m_LastSession->GetState () == eSSU2SessionStateClosing)
m_LastSession->RequestTermination (eSSU2TerminationReasonIdleTimeout); // send termination again
break;
case eSSU2SessionStateClosingConfirmed:
case eSSU2SessionStateTerminated:
m_LastSession = nullptr;
break;
default:
LogPrint (eLogWarning, "SSU2: Invalid session state ", (int)m_LastSession->GetState ());
}
}
else
{
// check pending sessions if it's SessionCreated or Retry
auto it1 = m_PendingOutgoingSessions.find (senderEndpoint);
if (it1 != m_PendingOutgoingSessions.end ())
{
if (it1->second->GetState () == eSSU2SessionStateSessionRequestSent &&
it1->second->ProcessSessionCreated (buf, len))
{
std::lock_guard<std::mutex> l(m_PendingOutgoingSessionsMutex);
m_PendingOutgoingSessions.erase (it1); // we are done with that endpoint
}
else
it1->second->ProcessRetry (buf, len);
}
else if (!i2p::transport::transports.IsInReservedRange(senderEndpoint.address ()) && senderEndpoint.port ())
{
// assume new incoming session
auto session = std::make_shared<SSU2Session> (*this);
session->SetRemoteEndpoint (senderEndpoint);
session->ProcessFirstIncomingMessage (connID, buf, len);
}
else
LogPrint (eLogError, "SSU2: Incoming packet received from invalid endpoint ", senderEndpoint);
}
}
void SSU2Server::Send (const uint8_t * header, size_t headerLen, const uint8_t * payload, size_t payloadLen,
const boost::asio::ip::udp::endpoint& to)
{
if (m_IsThroughProxy)
{
SendThroughProxy (header, headerLen, nullptr, 0, payload, payloadLen, to);
return;
}
std::vector<boost::asio::const_buffer> bufs
{
boost::asio::buffer (header, headerLen),
boost::asio::buffer (payload, payloadLen)
};
boost::system::error_code ec;
if (to.address ().is_v6 ())
{
if (!m_SocketV6.is_open ()) return;
m_SocketV6.send_to (bufs, to, 0, ec);
}
else
{
if (!m_SocketV4.is_open ()) return;
m_SocketV4.send_to (bufs, to, 0, ec);
}
if (!ec)
i2p::transport::transports.UpdateSentBytes (headerLen + payloadLen);
else
{
LogPrint (ec == boost::asio::error::would_block ? eLogInfo : eLogError,
"SSU2: Send exception: ", ec.message (), " to ", to);
}
}
void SSU2Server::Send (const uint8_t * header, size_t headerLen, const uint8_t * headerX, size_t headerXLen,
const uint8_t * payload, size_t payloadLen, const boost::asio::ip::udp::endpoint& to)
{
if (m_IsThroughProxy)
{
SendThroughProxy (header, headerLen, headerX, headerXLen, payload, payloadLen, to);
return;
}
std::vector<boost::asio::const_buffer> bufs
{
boost::asio::buffer (header, headerLen),
boost::asio::buffer (headerX, headerXLen),
boost::asio::buffer (payload, payloadLen)
};
boost::system::error_code ec;
if (to.address ().is_v6 ())
{
if (!m_SocketV6.is_open ()) return;
m_SocketV6.send_to (bufs, to, 0, ec);
}
else
{
if (!m_SocketV4.is_open ()) return;
m_SocketV4.send_to (bufs, to, 0, ec);
}
if (!ec)
i2p::transport::transports.UpdateSentBytes (headerLen + headerXLen + payloadLen);
else
{
LogPrint (ec == boost::asio::error::would_block ? eLogInfo : eLogError,
"SSU2: Send exception: ", ec.message (), " to ", to);
}
}
bool SSU2Server::CheckPendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep, bool peerTest)
{
auto s = FindPendingOutgoingSession (ep);
if (s)
{
if (peerTest)
{
// if peer test requested add it to the list for pending session
auto onEstablished = s->GetOnEstablished ();
if (onEstablished)
s->SetOnEstablished ([s, onEstablished]()
{
onEstablished ();
s->SendPeerTest ();
});
else
s->SetOnEstablished ([s]() { s->SendPeerTest (); });
}
return true;
}
return false;
}
bool SSU2Server::CreateSession (std::shared_ptr<const i2p::data::RouterInfo> router,
std::shared_ptr<const i2p::data::RouterInfo::Address> address, bool peerTest)
{
if (router && address)
{
// check if no session
auto existingSession = FindSession (router->GetIdentHash ());
if (existingSession)
{
// session with router found, trying to send peer test if requested
if (peerTest && existingSession->IsEstablished ())
GetService ().post ([existingSession]() { existingSession->SendPeerTest (); });
return false;
}
// check is no pending session
bool isValidEndpoint = !address->host.is_unspecified () && address->port;
if (isValidEndpoint)
{
if (i2p::transport::transports.IsInReservedRange(address->host)) return false;
if (CheckPendingOutgoingSession (boost::asio::ip::udp::endpoint (address->host, address->port), peerTest)) return false;
}
auto session = std::make_shared<SSU2Session> (*this, router, address);
if (!isValidEndpoint && router->GetProfile ()->HasLastEndpoint (address->IsV4 ()))
{
// router doesn't publish endpoint, but we connected before and hole punch might be alive
auto ep = router->GetProfile ()->GetLastEndpoint ();
if (IsConnectedRecently (ep, false))
{
if (CheckPendingOutgoingSession (ep, peerTest)) return false;
session->SetRemoteEndpoint (ep);
isValidEndpoint = true;
}
}
if (peerTest)
session->SetOnEstablished ([session]() {session->SendPeerTest (); });
if (isValidEndpoint) // we know endpoint
GetService ().post ([session]() { session->Connect (); });
else if (address->UsesIntroducer ()) // we don't know endpoint yet
GetService ().post (std::bind (&SSU2Server::ConnectThroughIntroducer, this, session));
else
return false;
}
else
return false;
return true;
}
void SSU2Server::ConnectThroughIntroducer (std::shared_ptr<SSU2Session> session)
{
if (!session) return;
auto address = session->GetAddress ();
if (!address) return;
session->WaitForIntroduction ();
auto ts = i2p::util::GetSecondsSinceEpoch ();
std::vector<int> indices; int i = 0;
// try to find existing session first
for (auto& it: address->ssu->introducers)
{
if (it.iTag && ts < it.iExp)
{
auto s = FindSession (it.iH);
if (s)
{
auto addr = s->GetAddress ();
if (addr && addr->IsIntroducer ())
{
s->Introduce (session, it.iTag);
return;
}
}
else
indices.push_back(i);
}
i++;
}
// we have to start a new session to an introducer
std::vector<i2p::data::IdentHash> newRouters;
std::shared_ptr<i2p::data::RouterInfo> r;
std::shared_ptr<const i2p::data::RouterInfo::Address> addr;
uint32_t relayTag = 0;
if (!indices.empty ())
{
if (indices.size () > 1)
std::shuffle (indices.begin(), indices.end(), m_Rng);
for (auto ind: indices)
{
const auto& introducer = address->ssu->introducers[ind];
// introducer is not expired, because in indices
r = i2p::data::netdb.FindRouter (introducer.iH);
if (r)
{
if (r->IsPublishedOn (i2p::context.GetRouterInfo ().GetCompatibleTransports (false) & // outgoing
(i2p::data::RouterInfo::eSSU2V4 | i2p::data::RouterInfo::eSSU2V6)))
{
relayTag = introducer.iTag;
addr = address->IsV6 () ? r->GetSSU2V6Address () : r->GetSSU2V4Address ();
if (addr && addr->IsIntroducer () && !addr->host.is_unspecified () && addr->port &&
!i2p::transport::transports.IsInReservedRange(addr->host))
break;
else
{
// address is invalid or not intrudcer, try another SSU2 address if exists
if (address->IsV4 ())
{
if (i2p::context.SupportsV6 ())
addr = r->GetSSU2V6Address ();
}
else
{
if (i2p::context.SupportsV4 ())
addr = r->GetSSU2V4Address ();
}
if (addr && addr->IsIntroducer () && !addr->host.is_unspecified () && addr->port &&
!i2p::transport::transports.IsInReservedRange(addr->host))
break;
else
{
// all addresses are invalid, try next introducer
relayTag = 0;
addr = nullptr;
r = nullptr;
}
}
}
else
r = nullptr;
}
else if (!i2p::data::IsRouterBanned (introducer.iH))
newRouters.push_back (introducer.iH);
}
}
if (r)
{
if (relayTag && addr)
{
// introducer and tag found connect to it through SSU2
auto s = FindPendingOutgoingSession (boost::asio::ip::udp::endpoint (addr->host, addr->port));
if (!s)
{
s = std::make_shared<SSU2Session> (*this, r, addr);
s->SetOnEstablished ([session, s, relayTag]() { s->Introduce (session, relayTag); });
s->Connect ();
}
else
{
auto onEstablished = s->GetOnEstablished ();
if (onEstablished)
s->SetOnEstablished ([session, s, relayTag, onEstablished]()
{
onEstablished ();
s->Introduce (session, relayTag);
});
else
s->SetOnEstablished ([session, s, relayTag]() {s->Introduce (session, relayTag); });
}
}
else
session->Done ();
}
else
{
// introducers not found, try to request them
for (auto& it: newRouters)
i2p::data::netdb.RequestDestination (it);
session->Done (); // don't wait for connect timeout
}
}
bool SSU2Server::StartPeerTest (std::shared_ptr<const i2p::data::RouterInfo> router, bool v4)
{
if (!router) return false;
auto addr = v4 ? router->GetSSU2V4Address () : router->GetSSU2V6Address ();
if (!addr) return false;
auto session = FindSession (router->GetIdentHash ());
if (session)
{
auto remoteAddr = session->GetAddress ();
if (!remoteAddr || !remoteAddr->IsPeerTesting () ||
(v4 && !remoteAddr->IsV4 ()) || (!v4 && !remoteAddr->IsV6 ())) return false;
if (session->IsEstablished ())
GetService ().post ([session]() { session->SendPeerTest (); });
else
session->SetOnEstablished ([session]() { session->SendPeerTest (); });
return true;
}
else
CreateSession (router, addr, true);
return true;
}
void SSU2Server::ScheduleTermination ()
{
m_TerminationTimer.expires_from_now (boost::posix_time::seconds(
SSU2_TERMINATION_CHECK_TIMEOUT + m_Rng () % SSU2_TERMINATION_CHECK_TIMEOUT_VARIANCE));
m_TerminationTimer.async_wait (std::bind (&SSU2Server::HandleTerminationTimer,
this, std::placeholders::_1));
}
void SSU2Server::HandleTerminationTimer (const boost::system::error_code& ecode)
{
if (ecode != boost::asio::error::operation_aborted)
{
auto ts = i2p::util::GetSecondsSinceEpoch ();
{
std::lock_guard<std::mutex> l(m_PendingOutgoingSessionsMutex);
for (auto it = m_PendingOutgoingSessions.begin (); it != m_PendingOutgoingSessions.end ();)
{
if (it->second->IsTerminationTimeoutExpired (ts))
{
//it->second->Terminate ();
it = m_PendingOutgoingSessions.erase (it);
}
else
it++;
}
}
for (auto it: m_Sessions)
{
auto state = it.second->GetState ();
if (state == eSSU2SessionStateTerminated || state == eSSU2SessionStateClosing)
it.second->Done ();
else if (it.second->IsTerminationTimeoutExpired (ts))
{
if (it.second->IsEstablished ())
it.second->RequestTermination (eSSU2TerminationReasonIdleTimeout);
else
it.second->Done ();
}
else
it.second->CleanUp (ts);
}
ScheduleTermination ();
}
}
void SSU2Server::ScheduleCleanup ()
{
m_CleanupTimer.expires_from_now (boost::posix_time::seconds(SSU2_CLEANUP_INTERVAL));
m_CleanupTimer.async_wait (std::bind (&SSU2Server::HandleCleanupTimer,
this, std::placeholders::_1));
}
void SSU2Server::HandleCleanupTimer (const boost::system::error_code& ecode)
{
if (ecode != boost::asio::error::operation_aborted)
{
auto ts = i2p::util::GetSecondsSinceEpoch ();
for (auto it = m_Relays.begin (); it != m_Relays.begin ();)
{
if (it->second.expired ())
it = m_Relays.erase (it);
else
it++;
}
for (auto it = m_PeerTests.begin (); it != m_PeerTests.end ();)
{
if (ts > it->second.second + SSU2_PEER_TEST_EXPIRATION_TIMEOUT || it->second.first.expired ())
{
LogPrint (eLogInfo, "SSU2: Peer test nonce ", it->first, " was not responded in ", SSU2_PEER_TEST_EXPIRATION_TIMEOUT, " seconds or session invalid. Deleted");
it = m_PeerTests.erase (it);
}
else
it++;
}
for (auto it = m_IncomingTokens.begin (); it != m_IncomingTokens.end (); )
{
if (ts > it->second.second)
it = m_IncomingTokens.erase (it);
else
it++;
}
for (auto it = m_OutgoingTokens.begin (); it != m_OutgoingTokens.end (); )
{
if (ts > it->second.second)
it = m_OutgoingTokens.erase (it);
else
it++;
}
for (auto it = m_ConnectedRecently.begin (); it != m_ConnectedRecently.end (); )
{
if (ts > it->second + SSU2_MAX_HOLE_PUNCH_EXPIRATION)
it = m_ConnectedRecently.erase (it);
else
it++;
}
for (auto it = m_RequestedPeerTests.begin (); it != m_RequestedPeerTests.end ();)
{
if (ts > it->second.second + SSU2_PEER_TEST_EXPIRATION_TIMEOUT)
it = m_RequestedPeerTests.erase (it);
else
it++;
}
{
std::lock_guard<std::mutex> l(m_SessionsByRouterHashMutex);
for (auto it = m_SessionsByRouterHash.begin (); it != m_SessionsByRouterHash.begin ();)
{
if (it->second.expired ())
it = m_SessionsByRouterHash.erase (it);
else
it++;
}
}
m_PacketsPool.CleanUpMt ();
m_SentPacketsPool.CleanUp ();
m_IncompleteMessagesPool.CleanUp ();
m_FragmentsPool.CleanUp ();
ScheduleCleanup ();
}
}
void SSU2Server::ScheduleResend (bool more)
{
m_ResendTimer.expires_from_now (boost::posix_time::milliseconds (more ?
(SSU2_RESEND_CHECK_MORE_TIMEOUT + m_Rng () % SSU2_RESEND_CHECK_MORE_TIMEOUT_VARIANCE):
(SSU2_RESEND_CHECK_TIMEOUT + m_Rng () % SSU2_RESEND_CHECK_TIMEOUT_VARIANCE)));
m_ResendTimer.async_wait (std::bind (&SSU2Server::HandleResendTimer,
this, std::placeholders::_1));
}
void SSU2Server::HandleResendTimer (const boost::system::error_code& ecode)
{
if (ecode != boost::asio::error::operation_aborted)
{
size_t resentPacketsNum = 0;
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
for (auto it: m_Sessions)
{
if (ts >= it.second->GetLastResendTime () + SSU2_RESEND_CHECK_TIMEOUT)
resentPacketsNum += it.second->Resend (ts);
if (resentPacketsNum > SSU2_MAX_RESEND_PACKETS) break;
}
for (auto it: m_PendingOutgoingSessions)
it.second->Resend (ts);
ScheduleResend (resentPacketsNum > SSU2_MAX_RESEND_PACKETS);
}
}
void SSU2Server::UpdateOutgoingToken (const boost::asio::ip::udp::endpoint& ep, uint64_t token, uint32_t exp)
{
m_OutgoingTokens[ep] = {token, exp};
}
uint64_t SSU2Server::FindOutgoingToken (const boost::asio::ip::udp::endpoint& ep)
{
auto it = m_OutgoingTokens.find (ep);
if (it != m_OutgoingTokens.end ())
{
if (i2p::util::GetSecondsSinceEpoch () + SSU2_TOKEN_EXPIRATION_THRESHOLD > it->second.second)
{
// token expired
m_OutgoingTokens.erase (it);
return 0;
}
return it->second.first;
}
return 0;
}
uint64_t SSU2Server::GetIncomingToken (const boost::asio::ip::udp::endpoint& ep)
{
auto ts = i2p::util::GetSecondsSinceEpoch ();
auto it = m_IncomingTokens.find (ep);
if (it != m_IncomingTokens.end ())
{
if (ts + SSU2_TOKEN_EXPIRATION_THRESHOLD <= it->second.second)
return it->second.first;
else // token expired
m_IncomingTokens.erase (it);
}
uint64_t token;
RAND_bytes ((uint8_t *)&token, 8);
m_IncomingTokens.emplace (ep, std::make_pair (token, uint32_t(ts + SSU2_TOKEN_EXPIRATION_TIMEOUT)));
return token;
}
std::pair<uint64_t, uint32_t> SSU2Server::NewIncomingToken (const boost::asio::ip::udp::endpoint& ep)
{
m_IncomingTokens.erase (ep); // drop previous
uint64_t token;
RAND_bytes ((uint8_t *)&token, 8);
auto ret = std::make_pair (token, uint32_t(i2p::util::GetSecondsSinceEpoch () + SSU2_NEXT_TOKEN_EXPIRATION_TIMEOUT));
m_IncomingTokens.emplace (ep, ret);
return ret;
}
std::vector<std::shared_ptr<SSU2Session> > SSU2Server::FindIntroducers (int maxNumIntroducers,
bool v4, const std::unordered_set<i2p::data::IdentHash>& excluded)
{
std::vector<std::shared_ptr<SSU2Session> > ret;
if (maxNumIntroducers <= 0 || m_Sessions.empty ()) return ret;
std::vector<std::shared_ptr<SSU2Session> > eligible;
eligible.reserve (m_Sessions.size ()/2);
auto ts = i2p::util::GetSecondsSinceEpoch ();
for (const auto& s : m_Sessions)
{
if (s.second->IsEstablished () && (s.second->GetRelayTag () && s.second->IsOutgoing ()) &&
ts < s.second->GetCreationTime () + SSU2_TO_INTRODUCER_SESSION_DURATION/2 &&
!excluded.count (s.second->GetRemoteIdentity ()->GetIdentHash ()) &&
((v4 && (s.second->GetRemoteTransports () & i2p::data::RouterInfo::eSSU2V4)) ||
(!v4 && (s.second->GetRemoteTransports () & i2p::data::RouterInfo::eSSU2V6))))
eligible.push_back (s.second);
}
if (eligible.size () <= (size_t)maxNumIntroducers)
return eligible;
else
std::sample (eligible.begin(), eligible.end(), std::back_inserter(ret), maxNumIntroducers, m_Rng);
return ret;
}
void SSU2Server::UpdateIntroducers (bool v4)
{
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
std::list<std::pair<i2p::data::IdentHash, uint32_t> > newList, impliedList;
auto& introducers = v4 ? m_Introducers : m_IntroducersV6;
std::unordered_set<i2p::data::IdentHash> excluded;
for (const auto& [ident, tag] : introducers)
{
std::shared_ptr<SSU2Session> session = FindSession (ident);
if (session)
excluded.insert (ident);
if (session)
{
if (session->IsEstablished () && session->GetRelayTag () && session->IsOutgoing () && // still session with introducer?
ts < session->GetCreationTime () + SSU2_TO_INTRODUCER_SESSION_EXPIRATION)
{
session->SendKeepAlive ();
if (ts < session->GetCreationTime () + SSU2_TO_INTRODUCER_SESSION_DURATION)
{
newList.push_back ({ident, session->GetRelayTag ()});
if (tag != session->GetRelayTag ())
{
LogPrint (eLogDebug, "SSU2: Introducer session to ", session->GetIdentHashBase64() , " was replaced. iTag ", tag, "->", session->GetRelayTag ());
i2p::context.UpdateSSU2Introducer (ident, v4, session->GetRelayTag (),
session->GetCreationTime () + SSU2_TO_INTRODUCER_SESSION_EXPIRATION);
}
}
else
{
impliedList.push_back ({ident, session->GetRelayTag ()}); // keep in introducers list, but not publish
session = nullptr;
}
}
else
session = nullptr;
}
if (!session)
i2p::context.RemoveSSU2Introducer (ident, v4);
}
int numOldSessions = 0;
if (newList.size () < SSU2_MAX_NUM_INTRODUCERS)
{
auto sessions = FindIntroducers (SSU2_MAX_NUM_INTRODUCERS - newList.size (), v4, excluded);
if (sessions.empty () && !impliedList.empty ())
{
LogPrint (eLogDebug, "SSU2: No new introducers found. Trying to reuse existing");
for (const auto& it : impliedList)
{
auto session = FindSession (it.first);
if (session)
{
if (std::find_if (newList.begin (), newList.end (),
[&ident = it.first](const auto& s){ return ident == s.first; }) == newList.end ())
{
sessions.push_back (session);
numOldSessions++;
}
}
}
impliedList.clear ();
}
for (const auto& it : sessions)
{
uint32_t tag = it->GetRelayTag ();
uint32_t exp = it->GetCreationTime () + SSU2_TO_INTRODUCER_SESSION_EXPIRATION;
if (!tag && ts >= exp)
continue; // don't publish expired introducer
i2p::data::RouterInfo::Introducer introducer;
introducer.iTag = tag;
introducer.iH = it->GetRemoteIdentity ()->GetIdentHash ();
introducer.iExp = exp;
excluded.insert (it->GetRemoteIdentity ()->GetIdentHash ());
if (i2p::context.AddSSU2Introducer (introducer, v4))
{
LogPrint (eLogDebug, "SSU2: Introducer added ", it->GetRelayTag (), " at ",
i2p::data::GetIdentHashAbbreviation (it->GetRemoteIdentity ()->GetIdentHash ()));
newList.push_back ({ it->GetRemoteIdentity ()->GetIdentHash (), tag });
it->SendKeepAlive ();
if (newList.size () >= SSU2_MAX_NUM_INTRODUCERS) break;
}
}
}
introducers = newList;
if (introducers.size () < SSU2_MAX_NUM_INTRODUCERS || numOldSessions)
{
// we need to create more sessions with relay tag
// exclude all existing sessions
excluded.clear ();
{
std::lock_guard<std::mutex> l(m_SessionsByRouterHashMutex);
for (const auto& [ident, s] : m_SessionsByRouterHash)
excluded.insert (ident);
}
// sesssion about to expire are not counted
for (auto i = introducers.size (); i < SSU2_MAX_NUM_INTRODUCERS + numOldSessions; i++)
{
auto introducer = i2p::data::netdb.GetRandomSSU2Introducer (v4, excluded);
if (introducer)
{
auto address = v4 ? introducer->GetSSU2V4Address () : introducer->GetSSU2V6Address ();
if (address)
{
CreateSession (introducer, address);
excluded.insert (introducer->GetIdentHash ());
}
}
else
{
LogPrint (eLogDebug, "SSU2: Can't find more introducers");
break;
}
}
}
introducers.splice (introducers.end (), impliedList); // insert non-published, but non-expired introducers back
}
void SSU2Server::ScheduleIntroducersUpdateTimer ()
{
if (m_IsPublished)
{
m_IntroducersUpdateTimer.expires_from_now (boost::posix_time::seconds(
SSU2_KEEP_ALIVE_INTERVAL + m_Rng () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE));
m_IntroducersUpdateTimer.async_wait (std::bind (&SSU2Server::HandleIntroducersUpdateTimer,
this, std::placeholders::_1, true));
}
}
void SSU2Server::RescheduleIntroducersUpdateTimer ()
{
if (m_IsPublished)
{
m_IntroducersUpdateTimer.cancel ();
i2p::context.ClearSSU2Introducers (true);
m_Introducers.clear ();
m_IntroducersUpdateTimer.expires_from_now (boost::posix_time::seconds(
(SSU2_KEEP_ALIVE_INTERVAL + m_Rng () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE)/2));
m_IntroducersUpdateTimer.async_wait (std::bind (&SSU2Server::HandleIntroducersUpdateTimer,
this, std::placeholders::_1, true));
}
}
void SSU2Server::ScheduleIntroducersUpdateTimerV6 ()
{
if (m_IsPublished)
{
m_IntroducersUpdateTimerV6.expires_from_now (boost::posix_time::seconds(
SSU2_KEEP_ALIVE_INTERVAL + m_Rng () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE));
m_IntroducersUpdateTimerV6.async_wait (std::bind (&SSU2Server::HandleIntroducersUpdateTimer,
this, std::placeholders::_1, false));
}
}
void SSU2Server::RescheduleIntroducersUpdateTimerV6 ()
{
if (m_IsPublished)
{
m_IntroducersUpdateTimerV6.cancel ();
i2p::context.ClearSSU2Introducers (false);
m_IntroducersV6.clear ();
m_IntroducersUpdateTimerV6.expires_from_now (boost::posix_time::seconds(
(SSU2_KEEP_ALIVE_INTERVAL + m_Rng () % SSU2_KEEP_ALIVE_INTERVAL_VARIANCE)/2));
m_IntroducersUpdateTimerV6.async_wait (std::bind (&SSU2Server::HandleIntroducersUpdateTimer,
this, std::placeholders::_1, false));
}
}
void SSU2Server::HandleIntroducersUpdateTimer (const boost::system::error_code& ecode, bool v4)
{
if (ecode != boost::asio::error::operation_aborted)
{
// timeout expired
if (v4)
{
if (i2p::context.GetTesting ())
{
// we still don't know if we need introducers
ScheduleIntroducersUpdateTimer ();
return;
}
if (i2p::context.GetStatus () != eRouterStatusFirewalled)
{
// we don't need introducers
i2p::context.ClearSSU2Introducers (true);
m_Introducers.clear ();
return;
}
// we are firewalled
auto addr = i2p::context.GetRouterInfo ().GetSSU2V4Address ();
if (addr && addr->ssu && addr->ssu->introducers.empty ())
i2p::context.SetUnreachable (true, false); // v4
UpdateIntroducers (true);
ScheduleIntroducersUpdateTimer ();
}
else
{
if (i2p::context.GetTestingV6 ())
{
// we still don't know if we need introducers
ScheduleIntroducersUpdateTimerV6 ();
return;
}
if (i2p::context.GetStatusV6 () != eRouterStatusFirewalled)
{
// we don't need introducers
i2p::context.ClearSSU2Introducers (false);
m_IntroducersV6.clear ();
return;
}
// we are firewalled
auto addr = i2p::context.GetRouterInfo ().GetSSU2V6Address ();
if (addr && addr->ssu && addr->ssu->introducers.empty ())
i2p::context.SetUnreachable (false, true); // v6
UpdateIntroducers (false);
ScheduleIntroducersUpdateTimerV6 ();
}
}
}
void SSU2Server::SendThroughProxy (const uint8_t * header, size_t headerLen, const uint8_t * headerX, size_t headerXLen,
const uint8_t * payload, size_t payloadLen, const boost::asio::ip::udp::endpoint& to)
{
if (!m_ProxyRelayEndpoint) return;
size_t requestHeaderSize = 0;
memset (m_UDPRequestHeader, 0, 3);
if (to.address ().is_v6 ())
{
m_UDPRequestHeader[3] = SOCKS5_ATYP_IPV6;
memcpy (m_UDPRequestHeader + 4, to.address ().to_v6().to_bytes().data(), 16);
requestHeaderSize = SOCKS5_UDP_IPV6_REQUEST_HEADER_SIZE;
}
else
{
m_UDPRequestHeader[3] = SOCKS5_ATYP_IPV4;
memcpy (m_UDPRequestHeader + 4, to.address ().to_v4().to_bytes().data(), 4);
requestHeaderSize = SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE;
}
htobe16buf (m_UDPRequestHeader + requestHeaderSize - 2, to.port ());
std::vector<boost::asio::const_buffer> bufs;
bufs.push_back (boost::asio::buffer (m_UDPRequestHeader, requestHeaderSize));
bufs.push_back (boost::asio::buffer (header, headerLen));
if (headerX) bufs.push_back (boost::asio::buffer (headerX, headerXLen));
bufs.push_back (boost::asio::buffer (payload, payloadLen));
boost::system::error_code ec;
m_SocketV4.send_to (bufs, *m_ProxyRelayEndpoint, 0, ec); // TODO: implement ipv6 proxy
if (!ec)
i2p::transport::transports.UpdateSentBytes (headerLen + payloadLen);
else
LogPrint (eLogError, "SSU2: Send exception: ", ec.message (), " to ", to);
}
void SSU2Server::ProcessNextPacketFromProxy (uint8_t * buf, size_t len)
{
if (buf[2]) // FRAG
{
LogPrint (eLogWarning, "SSU2: Proxy packet fragmentation is not supported");
return;
}
size_t offset = 0;
boost::asio::ip::udp::endpoint ep;
switch (buf[3]) // ATYP
{
case SOCKS5_ATYP_IPV4:
{
offset = SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE;
if (offset > len) return;
boost::asio::ip::address_v4::bytes_type bytes;
memcpy (bytes.data (), buf + 4, 4);
uint16_t port = bufbe16toh (buf + 8);
ep = boost::asio::ip::udp::endpoint (boost::asio::ip::address_v4 (bytes), port);
break;
}
case SOCKS5_ATYP_IPV6:
{
offset = SOCKS5_UDP_IPV6_REQUEST_HEADER_SIZE;
if (offset > len) return;
boost::asio::ip::address_v6::bytes_type bytes;
memcpy (bytes.data (), buf + 4, 16);
uint16_t port = bufbe16toh (buf + 20);
ep = boost::asio::ip::udp::endpoint (boost::asio::ip::address_v6 (bytes), port);
break;
}
default:
{
LogPrint (eLogWarning, "SSU2: Unknown ATYP ", (int)buf[3], " from proxy relay");
return;
}
}
ProcessNextPacket (buf + offset, len - offset, ep);
}
void SSU2Server::ConnectToProxy ()
{
if (!m_ProxyEndpoint) return;
m_UDPAssociateSocket.reset (new boost::asio::ip::tcp::socket (m_ReceiveService.GetService ()));
m_UDPAssociateSocket->async_connect (*m_ProxyEndpoint,
[this] (const boost::system::error_code& ecode)
{
if (ecode)
{
LogPrint (eLogError, "SSU2: Can't connect to proxy ", *m_ProxyEndpoint, " ", ecode.message ());
m_UDPAssociateSocket.reset (nullptr);
ReconnectToProxy ();
}
else
HandshakeWithProxy ();
});
}
void SSU2Server::HandshakeWithProxy ()
{
if (!m_UDPAssociateSocket) return;
m_UDPRequestHeader[0] = SOCKS5_VER;
m_UDPRequestHeader[1] = 1; // 1 method
m_UDPRequestHeader[2] = 0; // no authentication
boost::asio::async_write (*m_UDPAssociateSocket, boost::asio::buffer (m_UDPRequestHeader, 3), boost::asio::transfer_all(),
[this] (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
if (ecode)
{
LogPrint(eLogError, "SSU2: Proxy write error ", ecode.message());
m_UDPAssociateSocket.reset (nullptr);
ReconnectToProxy ();
}
else
ReadHandshakeWithProxyReply ();
});
}
void SSU2Server::ReadHandshakeWithProxyReply ()
{
if (!m_UDPAssociateSocket) return;
boost::asio::async_read (*m_UDPAssociateSocket, boost::asio::buffer (m_UDPRequestHeader, 2), boost::asio::transfer_all(),
[this] (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
if (ecode)
{
LogPrint(eLogError, "SSU2: Proxy read error ", ecode.message());
m_UDPAssociateSocket.reset (nullptr);
ReconnectToProxy ();
}
else
{
if (m_UDPRequestHeader[0] == SOCKS5_VER && !m_UDPRequestHeader[1])
SendUDPAssociateRequest ();
else
{
LogPrint(eLogError, "SSU2: Invalid proxy reply");
m_UDPAssociateSocket.reset (nullptr);
}
}
});
}
void SSU2Server::SendUDPAssociateRequest ()
{
if (!m_UDPAssociateSocket) return;
m_UDPRequestHeader[0] = SOCKS5_VER;
m_UDPRequestHeader[1] = SOCKS5_CMD_UDP_ASSOCIATE;
m_UDPRequestHeader[2] = 0; // RSV
m_UDPRequestHeader[3] = SOCKS5_ATYP_IPV4; // TODO: implement ipv6 proxy
memset (m_UDPRequestHeader + 4, 0, 6); // address and port all zeros
boost::asio::async_write (*m_UDPAssociateSocket, boost::asio::buffer (m_UDPRequestHeader, SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE), boost::asio::transfer_all(),
[this] (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
if (ecode)
{
LogPrint(eLogError, "SSU2: Proxy write error ", ecode.message());
m_UDPAssociateSocket.reset (nullptr);
ReconnectToProxy ();
}
else
ReadUDPAssociateReply ();
});
}
void SSU2Server::ReadUDPAssociateReply ()
{
if (!m_UDPAssociateSocket) return;
boost::asio::async_read (*m_UDPAssociateSocket, boost::asio::buffer (m_UDPRequestHeader, SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE), boost::asio::transfer_all(),
[this] (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
if (ecode)
{
LogPrint(eLogError, "SSU2: Proxy read error ", ecode.message());
m_UDPAssociateSocket.reset (nullptr);
ReconnectToProxy ();
}
else
{
if (m_UDPRequestHeader[0] == SOCKS5_VER && !m_UDPRequestHeader[1])
{
if (m_UDPRequestHeader[3] == SOCKS5_ATYP_IPV4)
{
boost::asio::ip::address_v4::bytes_type bytes;
memcpy (bytes.data (), m_UDPRequestHeader + 4, 4);
uint16_t port = bufbe16toh (m_UDPRequestHeader + 8);
m_ProxyRelayEndpoint.reset (new boost::asio::ip::udp::endpoint (boost::asio::ip::address_v4 (bytes), port));
m_SocketV4.open (boost::asio::ip::udp::v4 ());
Receive (m_SocketV4);
ReadUDPAssociateSocket ();
}
else
{
LogPrint(eLogError, "SSU2: Proxy UDP associate unsupported ATYP ", (int)m_UDPRequestHeader[3]);
m_UDPAssociateSocket.reset (nullptr);
}
}
else
{
LogPrint(eLogError, "SSU2: Proxy UDP associate error ", (int)m_UDPRequestHeader[1]);
m_UDPAssociateSocket.reset (nullptr);
}
}
});
}
void SSU2Server::ReadUDPAssociateSocket ()
{
if (!m_UDPAssociateSocket) return;
m_UDPAssociateSocket->async_read_some (boost::asio::buffer (m_UDPRequestHeader, 1),
[this] (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
if (ecode)
{
LogPrint(eLogWarning, "SSU2: Proxy UDP Associate socket error ", ecode.message());
m_UDPAssociateSocket.reset (nullptr);
m_ProxyRelayEndpoint.reset (nullptr);
m_SocketV4.close ();
ConnectToProxy (); // try to reconnect immediately
}
else
ReadUDPAssociateSocket ();
});
}
void SSU2Server::ReconnectToProxy ()
{
LogPrint(eLogInfo, "SSU2: Reconnect to proxy after ", SSU2_PROXY_CONNECT_RETRY_TIMEOUT, " seconds");
if (m_ProxyConnectRetryTimer)
m_ProxyConnectRetryTimer->cancel ();
else
m_ProxyConnectRetryTimer.reset (new boost::asio::deadline_timer (m_ReceiveService.GetService ()));
m_ProxyConnectRetryTimer->expires_from_now (boost::posix_time::seconds (SSU2_PROXY_CONNECT_RETRY_TIMEOUT));
m_ProxyConnectRetryTimer->async_wait (
[this](const boost::system::error_code& ecode)
{
if (ecode != boost::asio::error::operation_aborted)
{
m_UDPAssociateSocket.reset (nullptr);
m_ProxyRelayEndpoint.reset (nullptr);
LogPrint(eLogInfo, "SSU2: Reconnecting to proxy");
ConnectToProxy ();
}
});
}
bool SSU2Server::SetProxy (const std::string& address, uint16_t port)
{
boost::system::error_code ecode;
auto addr = boost::asio::ip::address::from_string (address, ecode);
if (!ecode && !addr.is_unspecified () && port)
{
m_IsThroughProxy = true;
m_ProxyEndpoint.reset (new boost::asio::ip::tcp::endpoint (addr, port));
}
else
{
if (ecode)
LogPrint (eLogError, "SSU2: Invalid proxy address ", address, " ", ecode.message());
return false;
}
return true;
}
}
}
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