mirror of
https://github.com/PurpleI2P/i2pd
synced 2024-11-08 23:40:12 +03:00
395 lines
15 KiB
C++
395 lines
15 KiB
C++
/*
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* Copyright (c) 2013-2024, 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 <string.h>
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#include "I2PEndian.h"
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#include "Crypto.h"
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#include "Log.h"
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#include "RouterContext.h"
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#include "I2NPProtocol.h"
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#include "Garlic.h"
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#include "ECIESX25519AEADRatchetSession.h"
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#include "Tunnel.h"
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#include "Transports.h"
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#include "TransitTunnel.h"
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namespace i2p
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{
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namespace tunnel
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{
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TransitTunnel::TransitTunnel (uint32_t receiveTunnelID,
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const i2p::data::IdentHash& nextIdent, uint32_t nextTunnelID,
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const i2p::crypto::AESKey& layerKey, const i2p::crypto::AESKey& ivKey):
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TunnelBase (receiveTunnelID, nextTunnelID, nextIdent),
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m_LayerKey (layerKey), m_IVKey (ivKey)
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{
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}
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void TransitTunnel::EncryptTunnelMsg (std::shared_ptr<const I2NPMessage> in, std::shared_ptr<I2NPMessage> out)
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{
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if (!m_Encryption)
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{
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m_Encryption.reset (new i2p::crypto::TunnelEncryption);
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m_Encryption->SetKeys (m_LayerKey, m_IVKey);
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}
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m_Encryption->Encrypt (in->GetPayload () + 4, out->GetPayload () + 4);
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i2p::transport::transports.UpdateTotalTransitTransmittedBytes (TUNNEL_DATA_MSG_SIZE);
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}
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TransitTunnelParticipant::~TransitTunnelParticipant ()
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{
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}
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void TransitTunnelParticipant::HandleTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage>&& tunnelMsg)
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{
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EncryptTunnelMsg (tunnelMsg, tunnelMsg);
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m_NumTransmittedBytes += tunnelMsg->GetLength ();
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htobe32buf (tunnelMsg->GetPayload (), GetNextTunnelID ());
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tunnelMsg->FillI2NPMessageHeader (eI2NPTunnelData);
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m_TunnelDataMsgs.push_back (tunnelMsg);
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}
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void TransitTunnelParticipant::FlushTunnelDataMsgs ()
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{
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if (!m_TunnelDataMsgs.empty ())
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{
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auto num = m_TunnelDataMsgs.size ();
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if (num > 1)
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LogPrint (eLogDebug, "TransitTunnel: ", GetTunnelID (), "->", GetNextTunnelID (), " ", num);
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i2p::transport::transports.SendMessages (GetNextIdentHash (), m_TunnelDataMsgs); // send and clear
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}
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}
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void TransitTunnel::SendTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage> msg)
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{
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LogPrint (eLogError, "TransitTunnel: We are not a gateway for ", GetTunnelID ());
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}
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void TransitTunnel::HandleTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage>&& tunnelMsg)
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{
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LogPrint (eLogError, "TransitTunnel: Incoming tunnel message is not supported ", GetTunnelID ());
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}
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void TransitTunnelGateway::SendTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage> msg)
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{
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TunnelMessageBlock block;
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block.deliveryType = eDeliveryTypeLocal;
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block.data = msg;
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std::unique_lock<std::mutex> l(m_SendMutex);
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m_Gateway.PutTunnelDataMsg (block);
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}
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void TransitTunnelGateway::FlushTunnelDataMsgs ()
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{
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std::unique_lock<std::mutex> l(m_SendMutex);
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m_Gateway.SendBuffer ();
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}
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void TransitTunnelEndpoint::HandleTunnelDataMsg (std::shared_ptr<i2p::I2NPMessage>&& tunnelMsg)
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{
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auto newMsg = CreateEmptyTunnelDataMsg (true);
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EncryptTunnelMsg (tunnelMsg, newMsg);
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LogPrint (eLogDebug, "TransitTunnel: handle msg for endpoint ", GetTunnelID ());
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m_Endpoint.HandleDecryptedTunnelDataMsg (newMsg);
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}
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std::shared_ptr<TransitTunnel> CreateTransitTunnel (uint32_t receiveTunnelID,
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const i2p::data::IdentHash& nextIdent, uint32_t nextTunnelID,
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const i2p::crypto::AESKey& layerKey, const i2p::crypto::AESKey& ivKey,
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bool isGateway, bool isEndpoint)
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{
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if (isEndpoint)
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{
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LogPrint (eLogDebug, "TransitTunnel: endpoint ", receiveTunnelID, " created");
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return std::make_shared<TransitTunnelEndpoint> (receiveTunnelID, nextIdent, nextTunnelID, layerKey, ivKey);
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}
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else if (isGateway)
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{
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LogPrint (eLogInfo, "TransitTunnel: gateway ", receiveTunnelID, " created");
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return std::make_shared<TransitTunnelGateway> (receiveTunnelID, nextIdent, nextTunnelID, layerKey, ivKey);
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}
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else
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{
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LogPrint (eLogDebug, "TransitTunnel: ", receiveTunnelID, "->", nextTunnelID, " created");
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return std::make_shared<TransitTunnelParticipant> (receiveTunnelID, nextIdent, nextTunnelID, layerKey, ivKey);
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}
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}
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void HandleShortTransitTunnelBuildMsg (uint8_t * buf, size_t len)
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{
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int num = buf[0];
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LogPrint (eLogDebug, "TransitTunnel: ShortTunnelBuild ", num, " records");
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if (num > i2p::tunnel::MAX_NUM_RECORDS)
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{
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LogPrint (eLogError, "TransitTunnel: Too many records in ShortTunnelBuild message ", num);
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return;
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}
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if (len < num*SHORT_TUNNEL_BUILD_RECORD_SIZE + 1)
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{
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LogPrint (eLogError, "TransitTunnel: ShortTunnelBuild message of ", num, " records is too short ", len);
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return;
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}
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const uint8_t * record = buf + 1;
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for (int i = 0; i < num; i++)
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{
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if (!memcmp (record, (const uint8_t *)i2p::context.GetRouterInfo ().GetIdentHash (), 16))
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{
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LogPrint (eLogDebug, "TransitTunnel: Short request record ", i, " is ours");
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uint8_t clearText[SHORT_REQUEST_RECORD_CLEAR_TEXT_SIZE];
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if (!i2p::context.DecryptTunnelShortRequestRecord (record + SHORT_REQUEST_RECORD_ENCRYPTED_OFFSET, clearText))
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{
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LogPrint (eLogWarning, "TransitTunnel: Can't decrypt short request record ", i);
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return;
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}
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if (clearText[SHORT_REQUEST_RECORD_LAYER_ENCRYPTION_TYPE]) // not AES
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{
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LogPrint (eLogWarning, "TransitTunnel: Unknown layer encryption type ", clearText[SHORT_REQUEST_RECORD_LAYER_ENCRYPTION_TYPE], " in short request record");
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return;
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}
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auto& noiseState = i2p::context.GetCurrentNoiseState ();
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uint8_t replyKey[32]; // AEAD/Chacha20/Poly1305
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i2p::crypto::AESKey layerKey, ivKey; // AES
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i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "SMTunnelReplyKey", noiseState.m_CK);
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memcpy (replyKey, noiseState.m_CK + 32, 32);
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i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "SMTunnelLayerKey", noiseState.m_CK);
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memcpy (layerKey, noiseState.m_CK + 32, 32);
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bool isEndpoint = clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG;
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if (isEndpoint)
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{
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i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "TunnelLayerIVKey", noiseState.m_CK);
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memcpy (ivKey, noiseState.m_CK + 32, 32);
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}
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else
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{
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if (!memcmp ((const uint8_t *)i2p::context.GetIdentHash (), clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32)) // if next ident is now ours
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{
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LogPrint (eLogWarning, "TransitTunnel: Next ident is ours in short request record");
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return;
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}
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memcpy (ivKey, noiseState.m_CK , 32);
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}
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// check if we accept this tunnel
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std::shared_ptr<i2p::tunnel::TransitTunnel> transitTunnel;
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uint8_t retCode = 0;
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if (!i2p::context.AcceptsTunnels () || i2p::context.GetCongestionLevel (false) >= CONGESTION_LEVEL_FULL)
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retCode = 30;
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if (!retCode)
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{
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// create new transit tunnel
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transitTunnel = i2p::tunnel::CreateTransitTunnel (
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bufbe32toh (clearText + SHORT_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET),
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clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
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bufbe32toh (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
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layerKey, ivKey,
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clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_GATEWAY_FLAG,
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clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG);
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if (!i2p::tunnel::tunnels.AddTransitTunnel (transitTunnel))
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retCode = 30;
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}
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// encrypt reply
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uint8_t nonce[12];
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memset (nonce, 0, 12);
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uint8_t * reply = buf + 1;
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for (int j = 0; j < num; j++)
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{
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nonce[4] = j; // nonce is record #
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if (j == i)
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{
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memset (reply + SHORT_RESPONSE_RECORD_OPTIONS_OFFSET, 0, 2); // no options
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reply[SHORT_RESPONSE_RECORD_RET_OFFSET] = retCode;
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if (!i2p::crypto::AEADChaCha20Poly1305 (reply, SHORT_TUNNEL_BUILD_RECORD_SIZE - 16,
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noiseState.m_H, 32, replyKey, nonce, reply, SHORT_TUNNEL_BUILD_RECORD_SIZE, true)) // encrypt
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{
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LogPrint (eLogWarning, "TransitTunnel: Short reply AEAD encryption failed");
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return;
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}
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}
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else
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i2p::crypto::ChaCha20 (reply, SHORT_TUNNEL_BUILD_RECORD_SIZE, replyKey, nonce, reply);
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reply += SHORT_TUNNEL_BUILD_RECORD_SIZE;
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}
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// send reply
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auto onDrop = [transitTunnel]()
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{
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if (transitTunnel)
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{
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auto t = transitTunnel->GetCreationTime ();
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if (t > i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT)
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// make transit tunnel expired
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transitTunnel->SetCreationTime (t - i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT);
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}
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};
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if (isEndpoint)
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{
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auto replyMsg = NewI2NPShortMessage ();
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replyMsg->Concat (buf, len);
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replyMsg->FillI2NPMessageHeader (eI2NPShortTunnelBuildReply, bufbe32toh (clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET));
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if (transitTunnel) replyMsg->onDrop = onDrop;
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if (memcmp ((const uint8_t *)i2p::context.GetIdentHash (),
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clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32)) // reply IBGW is not local?
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{
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i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "RGarlicKeyAndTag", noiseState.m_CK);
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uint64_t tag;
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memcpy (&tag, noiseState.m_CK, 8);
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// we send it to reply tunnel
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i2p::transport::transports.SendMessage (clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
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CreateTunnelGatewayMsg (bufbe32toh (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
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i2p::garlic::WrapECIESX25519Message (replyMsg, noiseState.m_CK + 32, tag)));
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}
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else
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{
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// IBGW is local
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uint32_t tunnelID = bufbe32toh (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET);
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auto tunnel = i2p::tunnel::tunnels.GetTunnel (tunnelID);
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if (tunnel)
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{
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tunnel->SendTunnelDataMsg (replyMsg);
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tunnel->FlushTunnelDataMsgs ();
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}
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else
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LogPrint (eLogWarning, "I2NP: Tunnel ", tunnelID, " not found for short tunnel build reply");
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}
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}
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else
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{
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auto msg = CreateI2NPMessage (eI2NPShortTunnelBuild, buf, len,
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bufbe32toh (clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET));
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if (transitTunnel) msg->onDrop = onDrop;
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i2p::transport::transports.SendMessage (clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, msg);
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}
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return;
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}
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record += SHORT_TUNNEL_BUILD_RECORD_SIZE;
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}
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}
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static bool HandleBuildRequestRecords (int num, uint8_t * records, uint8_t * clearText)
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{
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for (int i = 0; i < num; i++)
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{
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uint8_t * record = records + i*TUNNEL_BUILD_RECORD_SIZE;
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if (!memcmp (record + BUILD_REQUEST_RECORD_TO_PEER_OFFSET, (const uint8_t *)i2p::context.GetRouterInfo ().GetIdentHash (), 16))
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{
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LogPrint (eLogDebug, "TransitTunnel: Build request record ", i, " is ours");
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if (!i2p::context.DecryptTunnelBuildRecord (record + BUILD_REQUEST_RECORD_ENCRYPTED_OFFSET, clearText))
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{
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LogPrint (eLogWarning, "TransitTunnel: Failed to decrypt tunnel build record");
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return false;
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}
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if (!memcmp ((const uint8_t *)i2p::context.GetIdentHash (), clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32) && // if next ident is now ours
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!(clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG)) // and not endpoint
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{
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LogPrint (eLogWarning, "TransitTunnel: Next ident is ours in tunnel build record");
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return false;
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}
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uint8_t retCode = 0;
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// decide if we should accept tunnel
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bool accept = i2p::context.AcceptsTunnels ();
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if (accept)
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{
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auto congestionLevel = i2p::context.GetCongestionLevel (false);
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if (congestionLevel >= CONGESTION_LEVEL_MEDIUM)
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{
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if (congestionLevel < CONGESTION_LEVEL_FULL)
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{
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// random reject depending on congestion level
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int level = i2p::tunnel::tunnels.GetRng ()() % (CONGESTION_LEVEL_FULL - CONGESTION_LEVEL_MEDIUM) + CONGESTION_LEVEL_MEDIUM;
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if (congestionLevel > level)
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accept = false;
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}
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else
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accept = false;
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}
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}
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// replace record to reply
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if (accept)
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{
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auto transitTunnel = i2p::tunnel::CreateTransitTunnel (
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bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET),
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clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
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bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
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clearText + ECIES_BUILD_REQUEST_RECORD_LAYER_KEY_OFFSET,
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clearText + ECIES_BUILD_REQUEST_RECORD_IV_KEY_OFFSET,
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clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_GATEWAY_FLAG,
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clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG);
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if (!i2p::tunnel::tunnels.AddTransitTunnel (transitTunnel))
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retCode = 30;
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}
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else
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retCode = 30; // always reject with bandwidth reason (30)
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memset (record + ECIES_BUILD_RESPONSE_RECORD_OPTIONS_OFFSET, 0, 2); // no options
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record[ECIES_BUILD_RESPONSE_RECORD_RET_OFFSET] = retCode;
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// encrypt reply
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i2p::crypto::CBCEncryption encryption;
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for (int j = 0; j < num; j++)
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{
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uint8_t * reply = records + j*TUNNEL_BUILD_RECORD_SIZE;
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if (j == i)
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{
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uint8_t nonce[12];
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memset (nonce, 0, 12);
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auto& noiseState = i2p::context.GetCurrentNoiseState ();
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if (!i2p::crypto::AEADChaCha20Poly1305 (reply, TUNNEL_BUILD_RECORD_SIZE - 16,
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noiseState.m_H, 32, noiseState.m_CK, nonce, reply, TUNNEL_BUILD_RECORD_SIZE, true)) // encrypt
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{
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LogPrint (eLogWarning, "TransitTunnel: Reply AEAD encryption failed");
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return false;
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}
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}
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else
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{
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encryption.SetKey (clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_KEY_OFFSET);
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encryption.SetIV (clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_IV_OFFSET);
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encryption.Encrypt(reply, TUNNEL_BUILD_RECORD_SIZE, reply);
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}
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}
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return true;
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}
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}
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return false;
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}
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void HandleVariableTransitTunnelBuildMsg (uint8_t * buf, size_t len)
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{
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int num = buf[0];
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LogPrint (eLogDebug, "TransitTunnel: VariableTunnelBuild ", num, " records");
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if (num > i2p::tunnel::MAX_NUM_RECORDS)
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{
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LogPrint (eLogError, "TransitTunnle: Too many records in VaribleTunnelBuild message ", num);
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return;
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}
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if (len < num*TUNNEL_BUILD_RECORD_SIZE + 1)
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{
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LogPrint (eLogError, "TransitTunnel: VaribleTunnelBuild message of ", num, " records is too short ", len);
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return;
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}
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uint8_t clearText[ECIES_BUILD_REQUEST_RECORD_CLEAR_TEXT_SIZE];
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if (HandleBuildRequestRecords (num, buf + 1, clearText))
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{
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if (clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG) // we are endpoint of outboud tunnel
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{
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// so we send it to reply tunnel
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i2p::transport::transports.SendMessage (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
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CreateTunnelGatewayMsg (bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
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eI2NPVariableTunnelBuildReply, buf, len,
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bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
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}
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else
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i2p::transport::transports.SendMessage (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
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CreateI2NPMessage (eI2NPVariableTunnelBuild, buf, len,
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bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
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}
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}
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}
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}
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