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I2P: End-to-End encrypted and anonymous Internet
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597 lines
16 KiB
597 lines
16 KiB
/* |
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* Copyright (c) 2022, The PurpleI2P Project |
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* |
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* This file is part of Purple i2pd project and licensed under BSD3 |
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* |
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* See full license text in LICENSE file at top of project tree |
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*/ |
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#include "Log.h" |
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#include "RouterContext.h" |
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#include "Transports.h" |
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#include "NetDb.hpp" |
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#include "Config.h" |
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#include "SSU2.h" |
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namespace i2p |
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{ |
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namespace transport |
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{ |
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SSU2Server::SSU2Server (): |
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RunnableServiceWithWork ("SSU2"), m_ReceiveService ("SSU2r"), |
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m_SocketV4 (m_ReceiveService.GetService ()), m_SocketV6 (m_ReceiveService.GetService ()), |
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m_TerminationTimer (GetService ()), m_ResendTimer (GetService ()) |
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{ |
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} |
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void SSU2Server::Start () |
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{ |
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if (!IsRunning ()) |
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{ |
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StartIOService (); |
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bool found = false; |
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auto& addresses = i2p::context.GetRouterInfo ().GetAddresses (); |
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for (const auto& address: addresses) |
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{ |
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if (!address) continue; |
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if (address->transportStyle == i2p::data::RouterInfo::eTransportSSU2) |
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{ |
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auto port = address->port; |
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if (!port) |
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{ |
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uint16_t ssu2Port; i2p::config::GetOption ("ssu2.port", ssu2Port); |
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if (ssu2Port) port = ssu2Port; |
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else |
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{ |
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uint16_t p; i2p::config::GetOption ("port", p); |
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if (p) port = p; |
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} |
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} |
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if (port) |
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{ |
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if (address->IsV4 ()) |
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{ |
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found = true; |
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OpenSocket (boost::asio::ip::udp::endpoint (boost::asio::ip::udp::v4(), port)); |
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m_ReceiveService.GetService ().post( |
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[this]() |
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{ |
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Receive (m_SocketV4); |
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}); |
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} |
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if (address->IsV6 ()) |
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{ |
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found = true; |
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OpenSocket (boost::asio::ip::udp::endpoint (boost::asio::ip::udp::v6(), port)); |
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m_ReceiveService.GetService ().post( |
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[this]() |
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{ |
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Receive (m_SocketV6); |
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}); |
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} |
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} |
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else |
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LogPrint (eLogError, "SSU2: Can't start server because port not specified"); |
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} |
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} |
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if (found) |
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m_ReceiveService.Start (); |
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ScheduleTermination (); |
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} |
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} |
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void SSU2Server::Stop () |
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{ |
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for (auto& it: m_Sessions) |
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it.second->Done (); |
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m_Sessions.clear (); |
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m_SessionsByRouterHash.clear (); |
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m_PendingOutgoingSessions.clear (); |
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if (context.SupportsV4 () || context.SupportsV6 ()) |
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m_ReceiveService.Stop (); |
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m_SocketV4.close (); |
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m_SocketV6.close (); |
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if (IsRunning ()) |
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m_TerminationTimer.cancel (); |
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StopIOService (); |
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} |
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boost::asio::ip::udp::socket& SSU2Server::OpenSocket (const boost::asio::ip::udp::endpoint& localEndpoint) |
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{ |
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boost::asio::ip::udp::socket& socket = localEndpoint.address ().is_v6 () ? m_SocketV6 : m_SocketV4; |
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try |
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{ |
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socket.open (localEndpoint.protocol ()); |
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if (localEndpoint.address ().is_v6 ()) |
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socket.set_option (boost::asio::ip::v6_only (true)); |
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socket.set_option (boost::asio::socket_base::receive_buffer_size (SSU2_SOCKET_RECEIVE_BUFFER_SIZE)); |
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socket.set_option (boost::asio::socket_base::send_buffer_size (SSU2_SOCKET_SEND_BUFFER_SIZE)); |
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socket.bind (localEndpoint); |
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LogPrint (eLogInfo, "SSU2: Start listening on ", localEndpoint); |
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} |
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catch (std::exception& ex ) |
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{ |
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LogPrint (eLogError, "SSU2: Failed to bind to ", localEndpoint, ": ", ex.what()); |
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ThrowFatal ("Unable to start SSU2 transport on ", localEndpoint, ": ", ex.what ()); |
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} |
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return socket; |
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} |
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void SSU2Server::Receive (boost::asio::ip::udp::socket& socket) |
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{ |
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Packet * packet = m_PacketsPool.AcquireMt (); |
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socket.async_receive_from (boost::asio::buffer (packet->buf, SSU2_MTU), packet->from, |
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std::bind (&SSU2Server::HandleReceivedFrom, this, std::placeholders::_1, std::placeholders::_2, packet, std::ref (socket))); |
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} |
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void SSU2Server::HandleReceivedFrom (const boost::system::error_code& ecode, size_t bytes_transferred, |
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Packet * packet, boost::asio::ip::udp::socket& socket) |
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{ |
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if (!ecode) |
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{ |
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i2p::transport::transports.UpdateReceivedBytes (bytes_transferred); |
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packet->len = bytes_transferred; |
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boost::system::error_code ec; |
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size_t moreBytes = socket.available (ec); |
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if (!ec && moreBytes) |
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{ |
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std::vector<Packet *> packets; |
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packets.push_back (packet); |
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while (moreBytes && packets.size () < 32) |
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{ |
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packet = m_PacketsPool.AcquireMt (); |
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packet->len = socket.receive_from (boost::asio::buffer (packet->buf, SSU2_MTU), packet->from, 0, ec); |
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if (!ec) |
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{ |
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i2p::transport::transports.UpdateReceivedBytes (packet->len); |
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packets.push_back (packet); |
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moreBytes = socket.available(ec); |
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if (ec) break; |
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} |
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else |
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{ |
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LogPrint (eLogError, "SSU2: receive_from error: code ", ec.value(), ": ", ec.message ()); |
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m_PacketsPool.ReleaseMt (packet); |
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break; |
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} |
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} |
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GetService ().post (std::bind (&SSU2Server::HandleReceivedPackets, this, packets)); |
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} |
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else |
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GetService ().post (std::bind (&SSU2Server::HandleReceivedPacket, this, packet)); |
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Receive (socket); |
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} |
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else |
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{ |
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m_PacketsPool.ReleaseMt (packet); |
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if (ecode != boost::asio::error::operation_aborted) |
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{ |
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LogPrint (eLogError, "SSU2: Receive error: code ", ecode.value(), ": ", ecode.message ()); |
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auto ep = socket.local_endpoint (); |
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socket.close (); |
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OpenSocket (ep); |
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Receive (socket); |
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} |
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} |
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} |
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void SSU2Server::HandleReceivedPacket (Packet * packet) |
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{ |
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if (packet) |
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{ |
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ProcessNextPacket (packet->buf, packet->len, packet->from); |
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m_PacketsPool.ReleaseMt (packet); |
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if (m_LastSession) m_LastSession->FlushData (); |
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} |
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} |
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void SSU2Server::HandleReceivedPackets (std::vector<Packet *> packets) |
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{ |
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for (auto& packet: packets) |
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ProcessNextPacket (packet->buf, packet->len, packet->from); |
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m_PacketsPool.ReleaseMt (packets); |
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if (m_LastSession) m_LastSession->FlushData (); |
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} |
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void SSU2Server::AddSession (std::shared_ptr<SSU2Session> session) |
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{ |
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if (session) |
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{ |
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m_Sessions.emplace (session->GetConnID (), session); |
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AddSessionByRouterHash (session); |
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} |
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} |
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void SSU2Server::RemoveSession (uint64_t connID) |
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{ |
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auto it = m_Sessions.find (connID); |
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if (it != m_Sessions.end ()) |
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{ |
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auto ident = it->second->GetRemoteIdentity (); |
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if (ident) |
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m_SessionsByRouterHash.erase (ident->GetIdentHash ()); |
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m_Sessions.erase (it); |
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} |
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} |
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void SSU2Server::AddSessionByRouterHash (std::shared_ptr<SSU2Session> session) |
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{ |
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if (session) |
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{ |
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auto ident = session->GetRemoteIdentity (); |
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if (ident) |
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{ |
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auto ret = m_SessionsByRouterHash.emplace (ident->GetIdentHash (), session); |
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if (!ret.second) |
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{ |
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// session already exists |
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LogPrint (eLogWarning, "SSU2: Session to ", ident->GetIdentHash ().ToBase64 (), " aready exists"); |
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// terminate existing |
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GetService ().post (std::bind (&SSU2Session::Terminate, ret.first->second)); |
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// update session |
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ret.first->second = session; |
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} |
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} |
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} |
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} |
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void SSU2Server::AddPendingOutgoingSession (std::shared_ptr<SSU2Session> session) |
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{ |
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if (session) |
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m_PendingOutgoingSessions.emplace (session->GetRemoteEndpoint (), session); |
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} |
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std::shared_ptr<SSU2Session> SSU2Server::FindSession (const i2p::data::IdentHash& ident) const |
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{ |
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auto it = m_SessionsByRouterHash.find (ident); |
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if (it != m_SessionsByRouterHash.end ()) |
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return it->second; |
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return nullptr; |
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} |
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std::shared_ptr<SSU2Session> SSU2Server::GetRandomSession (i2p::data::RouterInfo::CompatibleTransports remoteTransports) const |
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{ |
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if (m_Sessions.empty ()) return nullptr; |
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uint16_t ind; |
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RAND_bytes ((uint8_t *)&ind, sizeof (ind)); |
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ind %= m_Sessions.size (); |
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auto it = m_Sessions.begin (); |
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std::advance (it, ind); |
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while (it != m_Sessions.end ()) |
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{ |
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if (it->second->GetRemoteTransports () & remoteTransports) |
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return it->second; |
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it++; |
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} |
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// not found, try from begining |
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it = m_Sessions.begin (); |
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while (it != m_Sessions.end () && ind) |
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{ |
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if (it->second->GetRemoteTransports () & remoteTransports) |
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return it->second; |
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it++; ind--; |
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} |
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return nullptr; |
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} |
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void SSU2Server::AddRelay (uint32_t tag, std::shared_ptr<SSU2Session> relay) |
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{ |
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m_Relays.emplace (tag, relay); |
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} |
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void SSU2Server::RemoveRelay (uint32_t tag) |
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{ |
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m_Relays.erase (tag); |
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} |
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std::shared_ptr<SSU2Session> SSU2Server::FindRelaySession (uint32_t tag) |
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{ |
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auto it = m_Relays.find (tag); |
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if (it != m_Relays.end ()) |
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{ |
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if (it->second->IsEstablished ()) |
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return it->second; |
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else |
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m_Relays.erase (it); |
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} |
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return nullptr; |
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} |
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void SSU2Server::ProcessNextPacket (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint) |
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{ |
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if (len < 24) return; |
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uint64_t connID; |
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memcpy (&connID, buf, 8); |
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connID ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 24)); |
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if (!m_LastSession || m_LastSession->GetConnID () != connID) |
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{ |
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if (m_LastSession) m_LastSession->FlushData (); |
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auto it = m_Sessions.find (connID); |
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if (it != m_Sessions.end ()) |
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m_LastSession = it->second; |
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else |
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m_LastSession = nullptr; |
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} |
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if (m_LastSession) |
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{ |
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switch (m_LastSession->GetState ()) |
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{ |
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case eSSU2SessionStateEstablished: |
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m_LastSession->ProcessData (buf, len); |
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break; |
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case eSSU2SessionStateUnknown: |
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m_LastSession->ProcessSessionConfirmed (buf, len); |
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break; |
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case eSSU2SessionStateIntroduced: |
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m_LastSession->SetRemoteEndpoint (senderEndpoint); |
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m_LastSession->ProcessHolePunch (buf, len); |
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break; |
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case eSSU2SessionStatePeerTest: |
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m_LastSession->SetRemoteEndpoint (senderEndpoint); |
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m_LastSession->ProcessPeerTest (buf, len); |
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break; |
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default: |
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LogPrint (eLogWarning, "SSU2: Invalid session state ", (int)m_LastSession->GetState ()); |
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} |
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} |
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else |
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{ |
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// check pending sessions if it's SessionCreated or Retry |
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auto it1 = m_PendingOutgoingSessions.find (senderEndpoint); |
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if (it1 != m_PendingOutgoingSessions.end ()) |
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{ |
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if (it1->second->ProcessSessionCreated (buf, len)) |
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m_PendingOutgoingSessions.erase (it1); // we are done with that endpoint |
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else |
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it1->second->ProcessRetry (buf, len); |
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} |
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else |
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{ |
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// assume new incoming session |
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auto session = std::make_shared<SSU2Session> (*this); |
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session->SetRemoteEndpoint (senderEndpoint); |
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session->ProcessFirstIncomingMessage (connID, buf, len); |
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} |
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} |
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} |
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void SSU2Server::Send (const uint8_t * header, size_t headerLen, const uint8_t * payload, size_t payloadLen, |
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const boost::asio::ip::udp::endpoint& to) |
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{ |
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std::vector<boost::asio::const_buffer> bufs |
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{ |
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boost::asio::buffer (header, headerLen), |
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boost::asio::buffer (payload, payloadLen) |
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}; |
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boost::system::error_code ec; |
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if (to.address ().is_v6 ()) |
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m_SocketV6.send_to (bufs, to, 0, ec); |
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else |
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m_SocketV4.send_to (bufs, to, 0, ec); |
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if (!ec) |
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i2p::transport::transports.UpdateSentBytes (headerLen + payloadLen); |
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else |
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LogPrint (eLogError, "SSU2: Send exception: ", ec.message (), " to ", to); |
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} |
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void SSU2Server::Send (const uint8_t * header, size_t headerLen, const uint8_t * headerX, size_t headerXLen, |
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const uint8_t * payload, size_t payloadLen, const boost::asio::ip::udp::endpoint& to) |
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{ |
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std::vector<boost::asio::const_buffer> bufs |
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{ |
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boost::asio::buffer (header, headerLen), |
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boost::asio::buffer (headerX, headerXLen), |
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boost::asio::buffer (payload, payloadLen) |
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}; |
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boost::system::error_code ec; |
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if (to.address ().is_v6 ()) |
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m_SocketV6.send_to (bufs, to, 0, ec); |
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else |
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m_SocketV4.send_to (bufs, to, 0, ec); |
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if (!ec) |
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i2p::transport::transports.UpdateSentBytes (headerLen + headerXLen + payloadLen); |
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else |
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LogPrint (eLogError, "SSU2: Send exception: ", ec.message (), " to ", to); |
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} |
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bool SSU2Server::CreateSession (std::shared_ptr<const i2p::data::RouterInfo> router, |
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std::shared_ptr<const i2p::data::RouterInfo::Address> address, bool peerTest) |
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{ |
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if (router && address) |
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{ |
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auto session = std::make_shared<SSU2Session> (*this, router, address); |
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if (peerTest) |
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session->SetOnEstablished ([session]() {session->SendPeerTest (); }); |
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if (address->UsesIntroducer ()) |
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GetService ().post (std::bind (&SSU2Server::ConnectThroughIntroducer, this, session)); |
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else |
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GetService ().post ([session]() { session->Connect (); }); |
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} |
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else |
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return false; |
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return true; |
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} |
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void SSU2Server::ConnectThroughIntroducer (std::shared_ptr<SSU2Session> session) |
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{ |
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if (!session) return; |
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auto address = session->GetAddress (); |
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if (!address) return; |
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session->SetState (eSSU2SessionStateIntroduced); |
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// try to find existing session first |
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for (auto& it: address->ssu->introducers) |
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{ |
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auto it1 = m_SessionsByRouterHash.find (it.iKey); |
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if (it1 != m_SessionsByRouterHash.end ()) |
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{ |
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it1->second->Introduce (session, it.iTag); |
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return; |
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} |
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} |
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// we have to start a new session to an introducer |
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std::shared_ptr<i2p::data::RouterInfo> r; |
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uint32_t relayTag = 0; |
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for (auto& it: address->ssu->introducers) |
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{ |
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r = i2p::data::netdb.FindRouter (it.iKey); |
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if (r && r->IsReachableFrom (i2p::context.GetRouterInfo ())) |
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{ |
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relayTag = it.iTag; |
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if (relayTag) break; |
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} |
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} |
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if (r) |
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{ |
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if (relayTag) |
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{ |
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// introducer and tag found connect to it through SSU2 |
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auto addr = address->IsV6 () ? r->GetSSU2V6Address () : r->GetSSU2V4Address (); |
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if (addr) |
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{ |
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auto s = std::make_shared<SSU2Session> (*this, r, addr); |
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s->SetOnEstablished ( |
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[session, s, relayTag]() |
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{ |
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s->Introduce (session, relayTag); |
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}); |
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s->Connect (); |
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} |
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} |
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} |
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else |
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{ |
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// introducers not found, try to request them |
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for (auto& it: address->ssu->introducers) |
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i2p::data::netdb.RequestDestination (it.iKey); |
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} |
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} |
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bool SSU2Server::StartPeerTest (std::shared_ptr<const i2p::data::RouterInfo> router, bool v4) |
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{ |
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if (!router) return false; |
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auto addr = v4 ? router->GetSSU2V4Address () : router->GetSSU2V6Address (); |
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if (!addr) return false; |
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auto it = m_SessionsByRouterHash.find (router->GetIdentHash ()); |
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if (it != m_SessionsByRouterHash.end ()) |
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{ |
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auto s = it->second; |
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if (it->second->IsEstablished ()) |
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GetService ().post ([s]() { s->SendPeerTest (); }); |
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else |
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s->SetOnEstablished ([s]() { s->SendPeerTest (); }); |
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return true; |
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} |
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CreateSession (router, addr, true); |
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return true; |
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} |
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void SSU2Server::ScheduleTermination () |
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{ |
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m_TerminationTimer.expires_from_now (boost::posix_time::seconds(SSU2_TERMINATION_CHECK_TIMEOUT)); |
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m_TerminationTimer.async_wait (std::bind (&SSU2Server::HandleTerminationTimer, |
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this, std::placeholders::_1)); |
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} |
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void SSU2Server::HandleTerminationTimer (const boost::system::error_code& ecode) |
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{ |
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if (ecode != boost::asio::error::operation_aborted) |
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{ |
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auto ts = i2p::util::GetSecondsSinceEpoch (); |
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for (auto it = m_PendingOutgoingSessions.begin (); it != m_PendingOutgoingSessions.end ();) |
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{ |
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if (it->second->IsTerminationTimeoutExpired (ts)) |
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{ |
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//it->second->Terminate (); |
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it = m_PendingOutgoingSessions.erase (it); |
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} |
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else |
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it++; |
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} |
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for (auto it = m_Sessions.begin (); it != m_Sessions.end ();) |
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{ |
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if (it->second->IsTerminationTimeoutExpired (ts)) |
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{ |
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if (it->second->IsEstablished ()) |
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it->second->TerminateByTimeout (); |
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if (it->second == m_LastSession) |
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m_LastSession = nullptr; |
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it = m_Sessions.erase (it); |
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} |
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else |
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{ |
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it->second->CleanUp (ts); |
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it++; |
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} |
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} |
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for (auto it = m_IncomingTokens.begin (); it != m_IncomingTokens.end (); ) |
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{ |
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if (ts > it->second.second) |
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it = m_IncomingTokens.erase (it); |
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else |
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it++; |
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} |
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for (auto it = m_OutgoingTokens.begin (); it != m_OutgoingTokens.end (); ) |
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{ |
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if (ts > it->second.second) |
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it = m_OutgoingTokens.erase (it); |
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else |
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it++; |
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} |
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ScheduleTermination (); |
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} |
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} |
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void SSU2Server::ScheduleResend () |
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{ |
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m_ResendTimer.expires_from_now (boost::posix_time::seconds(SSU2_RESEND_INTERVAL)); |
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m_ResendTimer.async_wait (std::bind (&SSU2Server::HandleResendTimer, |
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this, std::placeholders::_1)); |
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} |
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|
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void SSU2Server::HandleResendTimer (const boost::system::error_code& ecode) |
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{ |
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if (ecode != boost::asio::error::operation_aborted) |
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{ |
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auto ts = i2p::util::GetSecondsSinceEpoch (); |
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for (auto it: m_Sessions) |
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it.second->Resend (ts); |
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ScheduleResend (); |
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} |
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} |
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void SSU2Server::UpdateOutgoingToken (const boost::asio::ip::udp::endpoint& ep, uint64_t token, uint32_t exp) |
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{ |
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m_OutgoingTokens[ep] = {token, exp}; |
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} |
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uint64_t SSU2Server::FindOutgoingToken (const boost::asio::ip::udp::endpoint& ep) const |
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{ |
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auto it = m_OutgoingTokens.find (ep); |
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if (it != m_OutgoingTokens.end ()) |
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return it->second.first; |
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return 0; |
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} |
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std::pair<uint64_t, uint32_t> SSU2Server::GetIncomingToken (const boost::asio::ip::udp::endpoint& ep) |
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{ |
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auto it = m_IncomingTokens.find (ep); |
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if (it != m_IncomingTokens.end ()) |
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return it->second; |
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uint64_t token; |
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RAND_bytes ((uint8_t *)&token, 8); |
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auto ret = std::make_pair (token, i2p::util::GetSecondsSinceEpoch () + SSU2_TOKEN_EXPIRATION_TIMEOUT); |
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m_IncomingTokens.emplace (ep, ret); |
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return ret; |
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} |
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} |
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}
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