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515 lines
15 KiB
C++
515 lines
15 KiB
C++
/*
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* Copyright (c) 2013-2020, 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 <stdlib.h>
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#include <boost/bind.hpp>
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#include "Log.h"
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#include "Timestamp.h"
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#include "NetDb.hpp"
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#include "SSU.h"
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#include "SSUData.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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void IncompleteMessage::AttachNextFragment (const uint8_t * fragment, size_t fragmentSize)
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{
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if (msg->len + fragmentSize > msg->maxLen)
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{
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LogPrint (eLogWarning, "SSU: I2NP message size ", msg->maxLen, " is not enough");
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auto newMsg = NewI2NPMessage ();
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*newMsg = *msg;
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msg = newMsg;
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}
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if (msg->Concat (fragment, fragmentSize) < fragmentSize)
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LogPrint (eLogError, "SSU: I2NP buffer overflow ", msg->maxLen);
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nextFragmentNum++;
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}
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SSUData::SSUData (SSUSession& session):
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m_Session (session), m_ResendTimer (session.GetService ()),
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m_IncompleteMessagesCleanupTimer (session.GetService ()),
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m_MaxPacketSize (session.IsV6 () ? SSU_V6_MAX_PACKET_SIZE : SSU_V4_MAX_PACKET_SIZE),
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m_PacketSize (m_MaxPacketSize), m_LastMessageReceivedTime (0)
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{
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}
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SSUData::~SSUData ()
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{
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}
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void SSUData::Start ()
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{
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ScheduleIncompleteMessagesCleanup ();
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}
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void SSUData::Stop ()
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{
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m_ResendTimer.cancel ();
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m_IncompleteMessagesCleanupTimer.cancel ();
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m_IncompleteMessages.clear ();
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m_SentMessages.clear ();
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m_ReceivedMessages.clear ();
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}
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void SSUData::AdjustPacketSize (std::shared_ptr<const i2p::data::RouterInfo> remoteRouter)
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{
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if (!remoteRouter) return;
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auto ssuAddress = remoteRouter->GetSSUAddress ();
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if (ssuAddress && ssuAddress->ssu->mtu)
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{
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if (m_Session.IsV6 ())
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m_PacketSize = ssuAddress->ssu->mtu - IPV6_HEADER_SIZE - UDP_HEADER_SIZE;
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else
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m_PacketSize = ssuAddress->ssu->mtu - IPV4_HEADER_SIZE - UDP_HEADER_SIZE;
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if (m_PacketSize > 0)
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{
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// make sure packet size multiple of 16
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m_PacketSize >>= 4;
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m_PacketSize <<= 4;
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if (m_PacketSize > m_MaxPacketSize) m_PacketSize = m_MaxPacketSize;
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LogPrint (eLogDebug, "SSU: MTU=", ssuAddress->ssu->mtu, " packet size=", m_PacketSize);
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}
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else
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{
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LogPrint (eLogWarning, "SSU: Unexpected MTU ", ssuAddress->ssu->mtu);
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m_PacketSize = m_MaxPacketSize;
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}
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}
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}
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void SSUData::UpdatePacketSize (const i2p::data::IdentHash& remoteIdent)
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{
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auto routerInfo = i2p::data::netdb.FindRouter (remoteIdent);
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if (routerInfo)
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AdjustPacketSize (routerInfo);
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}
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void SSUData::ProcessSentMessageAck (uint32_t msgID)
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{
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auto it = m_SentMessages.find (msgID);
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if (it != m_SentMessages.end ())
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{
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m_SentMessages.erase (it);
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if (m_SentMessages.empty ())
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m_ResendTimer.cancel ();
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}
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}
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void SSUData::ProcessAcks (uint8_t *& buf, uint8_t flag)
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{
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if (flag & DATA_FLAG_EXPLICIT_ACKS_INCLUDED)
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{
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// explicit ACKs
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uint8_t numAcks =*buf;
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buf++;
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for (int i = 0; i < numAcks; i++)
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ProcessSentMessageAck (bufbe32toh (buf+i*4));
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buf += numAcks*4;
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}
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if (flag & DATA_FLAG_ACK_BITFIELDS_INCLUDED)
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{
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// explicit ACK bitfields
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uint8_t numBitfields =*buf;
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buf++;
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for (int i = 0; i < numBitfields; i++)
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{
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uint32_t msgID = bufbe32toh (buf);
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buf += 4; // msgID
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auto it = m_SentMessages.find (msgID);
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// process individual Ack bitfields
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bool isNonLast = false;
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int fragment = 0;
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do
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{
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uint8_t bitfield = *buf;
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isNonLast = bitfield & 0x80;
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bitfield &= 0x7F; // clear MSB
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if (bitfield && it != m_SentMessages.end ())
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{
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int numSentFragments = it->second->fragments.size ();
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// process bits
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uint8_t mask = 0x01;
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for (int j = 0; j < 7; j++)
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{
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if (bitfield & mask)
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{
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if (fragment < numSentFragments)
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it->second->fragments[fragment].reset (nullptr);
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}
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fragment++;
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mask <<= 1;
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}
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}
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buf++;
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}
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while (isNonLast);
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}
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}
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}
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void SSUData::ProcessFragments (uint8_t * buf)
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{
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uint8_t numFragments = *buf; // number of fragments
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buf++;
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for (int i = 0; i < numFragments; i++)
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{
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uint32_t msgID = bufbe32toh (buf); // message ID
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buf += 4;
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uint8_t frag[4] = {0};
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memcpy (frag + 1, buf, 3);
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buf += 3;
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uint32_t fragmentInfo = bufbe32toh (frag); // fragment info
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uint16_t fragmentSize = fragmentInfo & 0x3FFF; // bits 0 - 13
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bool isLast = fragmentInfo & 0x010000; // bit 16
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uint8_t fragmentNum = fragmentInfo >> 17; // bits 23 - 17
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if (fragmentSize >= SSU_V4_MAX_PACKET_SIZE)
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{
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LogPrint (eLogError, "SSU: Fragment size ", fragmentSize, " exceeds max SSU packet size");
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return;
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}
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// find message with msgID
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auto it = m_IncompleteMessages.find (msgID);
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if (it == m_IncompleteMessages.end ())
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{
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// create new message
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auto msg = NewI2NPShortMessage ();
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msg->len -= I2NP_SHORT_HEADER_SIZE;
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it = m_IncompleteMessages.insert (std::make_pair (msgID,
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std::unique_ptr<IncompleteMessage>(new IncompleteMessage (msg)))).first;
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}
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std::unique_ptr<IncompleteMessage>& incompleteMessage = it->second;
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// handle current fragment
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if (fragmentNum == incompleteMessage->nextFragmentNum)
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{
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// expected fragment
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incompleteMessage->AttachNextFragment (buf, fragmentSize);
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if (!isLast && !incompleteMessage->savedFragments.empty ())
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{
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// try saved fragments
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for (auto it1 = incompleteMessage->savedFragments.begin (); it1 != incompleteMessage->savedFragments.end ();)
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{
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auto& savedFragment = *it1;
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if (savedFragment->fragmentNum == incompleteMessage->nextFragmentNum)
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{
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incompleteMessage->AttachNextFragment (savedFragment->buf, savedFragment->len);
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isLast = savedFragment->isLast;
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incompleteMessage->savedFragments.erase (it1++);
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}
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else
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break;
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}
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if (isLast)
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LogPrint (eLogDebug, "SSU: Message ", msgID, " complete");
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}
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}
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else
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{
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if (fragmentNum < incompleteMessage->nextFragmentNum)
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// duplicate fragment
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LogPrint (eLogWarning, "SSU: Duplicate fragment ", (int)fragmentNum, " of message ", msgID, ", ignored");
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else
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{
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// missing fragment
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LogPrint (eLogWarning, "SSU: Missing fragments from ", (int)incompleteMessage->nextFragmentNum, " to ", fragmentNum - 1, " of message ", msgID);
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auto savedFragment = new Fragment (fragmentNum, buf, fragmentSize, isLast);
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if (incompleteMessage->savedFragments.insert (std::unique_ptr<Fragment>(savedFragment)).second)
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incompleteMessage->lastFragmentInsertTime = i2p::util::GetSecondsSinceEpoch ();
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else
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LogPrint (eLogWarning, "SSU: Fragment ", (int)fragmentNum, " of message ", msgID, " already saved");
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}
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isLast = false;
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}
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if (isLast)
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{
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// delete incomplete message
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auto msg = incompleteMessage->msg;
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incompleteMessage->msg = nullptr;
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m_IncompleteMessages.erase (msgID);
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// process message
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SendMsgAck (msgID);
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msg->FromSSU (msgID);
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if (m_Session.GetState () == eSessionStateEstablished)
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{
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if (!m_ReceivedMessages.count (msgID))
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{
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m_ReceivedMessages.insert (msgID);
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m_LastMessageReceivedTime = i2p::util::GetSecondsSinceEpoch ();
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if (!msg->IsExpired ())
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{
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m_Handler.PutNextMessage (msg);
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}
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else
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LogPrint (eLogDebug, "SSU: message expired");
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}
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else
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LogPrint (eLogWarning, "SSU: Message ", msgID, " already received");
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}
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else
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{
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// we expect DeliveryStatus
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if (msg->GetTypeID () == eI2NPDeliveryStatus)
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{
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LogPrint (eLogDebug, "SSU: session established");
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m_Session.Established ();
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}
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else
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LogPrint (eLogError, "SSU: unexpected message ", (int)msg->GetTypeID ());
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}
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}
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else
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SendFragmentAck (msgID, fragmentNum);
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buf += fragmentSize;
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}
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}
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void SSUData::FlushReceivedMessage ()
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{
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m_Handler.Flush ();
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}
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void SSUData::ProcessMessage (uint8_t * buf, size_t len)
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{
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//uint8_t * start = buf;
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uint8_t flag = *buf;
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buf++;
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LogPrint (eLogDebug, "SSU: Process data, flags=", (int)flag, ", len=", len);
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// process acks if presented
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if (flag & (DATA_FLAG_ACK_BITFIELDS_INCLUDED | DATA_FLAG_EXPLICIT_ACKS_INCLUDED))
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ProcessAcks (buf, flag);
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// extended data if presented
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if (flag & DATA_FLAG_EXTENDED_DATA_INCLUDED)
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{
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uint8_t extendedDataSize = *buf;
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buf++; // size
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LogPrint (eLogDebug, "SSU: extended data of ", extendedDataSize, " bytes present");
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buf += extendedDataSize;
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}
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// process data
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ProcessFragments (buf);
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}
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void SSUData::Send (std::shared_ptr<i2p::I2NPMessage> msg)
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{
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uint32_t msgID = msg->ToSSU ();
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if (m_SentMessages.count (msgID) > 0)
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{
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LogPrint (eLogWarning, "SSU: message ", msgID, " already sent");
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return;
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}
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if (m_SentMessages.empty ()) // schedule resend at first message only
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ScheduleResend ();
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auto ret = m_SentMessages.insert (std::make_pair (msgID, std::unique_ptr<SentMessage>(new SentMessage)));
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std::unique_ptr<SentMessage>& sentMessage = ret.first->second;
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if (ret.second)
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{
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sentMessage->nextResendTime = i2p::util::GetSecondsSinceEpoch () + RESEND_INTERVAL;
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sentMessage->numResends = 0;
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}
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auto& fragments = sentMessage->fragments;
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size_t payloadSize = m_PacketSize - sizeof (SSUHeader) - 9; // 9 = flag + #frg(1) + messageID(4) + frag info (3)
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size_t len = msg->GetLength ();
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uint8_t * msgBuf = msg->GetSSUHeader ();
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uint32_t fragmentNum = 0;
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while (len > 0 && fragmentNum <= 127)
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{
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Fragment * fragment = new Fragment;
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fragment->fragmentNum = fragmentNum;
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uint8_t * buf = fragment->buf;
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uint8_t * payload = buf + sizeof (SSUHeader);
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*payload = DATA_FLAG_WANT_REPLY; // for compatibility
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payload++;
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*payload = 1; // always 1 message fragment per message
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payload++;
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htobe32buf (payload, msgID);
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payload += 4;
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bool isLast = (len <= payloadSize) || fragmentNum == 127; // 127 fragments max
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size_t size = isLast ? len : payloadSize;
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uint32_t fragmentInfo = (fragmentNum << 17);
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if (isLast)
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fragmentInfo |= 0x010000;
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fragmentInfo |= size;
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fragmentInfo = htobe32 (fragmentInfo);
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memcpy (payload, (uint8_t *)(&fragmentInfo) + 1, 3);
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payload += 3;
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memcpy (payload, msgBuf, size);
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size += payload - buf;
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if (size & 0x0F) // make sure 16 bytes boundary
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size = ((size >> 4) + 1) << 4; // (/16 + 1)*16
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fragment->len = size;
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fragments.push_back (std::unique_ptr<Fragment> (fragment));
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// encrypt message with session key
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m_Session.FillHeaderAndEncrypt (PAYLOAD_TYPE_DATA, buf, size);
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try
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{
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m_Session.Send (buf, size);
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}
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catch (boost::system::system_error& ec)
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{
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LogPrint (eLogWarning, "SSU: Can't send data fragment ", ec.what ());
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}
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if (!isLast)
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{
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len -= payloadSize;
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msgBuf += payloadSize;
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}
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else
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len = 0;
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fragmentNum++;
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}
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}
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void SSUData::SendMsgAck (uint32_t msgID)
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{
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uint8_t buf[48 + 18] = {0}; // actual length is 44 = 37 + 7 but pad it to multiple of 16
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uint8_t * payload = buf + sizeof (SSUHeader);
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*payload = DATA_FLAG_EXPLICIT_ACKS_INCLUDED; // flag
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payload++;
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*payload = 1; // number of ACKs
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payload++;
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htobe32buf (payload, msgID); // msgID
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payload += 4;
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*payload = 0; // number of fragments
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// encrypt message with session key
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m_Session.FillHeaderAndEncrypt (PAYLOAD_TYPE_DATA, buf, 48);
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m_Session.Send (buf, 48);
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}
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void SSUData::SendFragmentAck (uint32_t msgID, int fragmentNum)
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{
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if (fragmentNum > 64)
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{
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LogPrint (eLogWarning, "SSU: Fragment number ", fragmentNum, " exceeds 64");
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return;
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}
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uint8_t buf[64 + 18] = {0};
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uint8_t * payload = buf + sizeof (SSUHeader);
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*payload = DATA_FLAG_ACK_BITFIELDS_INCLUDED; // flag
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payload++;
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*payload = 1; // number of ACK bitfields
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payload++;
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// one ack
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*(uint32_t *)(payload) = htobe32 (msgID); // msgID
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payload += 4;
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div_t d = div (fragmentNum, 7);
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memset (payload, 0x80, d.quot); // 0x80 means non-last
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payload += d.quot;
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*payload = 0x01 << d.rem; // set corresponding bit
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payload++;
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*payload = 0; // number of fragments
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size_t len = d.quot < 4 ? 48 : 64; // 48 = 37 + 7 + 4 (3+1)
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// encrypt message with session key
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m_Session.FillHeaderAndEncrypt (PAYLOAD_TYPE_DATA, buf, len);
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m_Session.Send (buf, len);
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}
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void SSUData::ScheduleResend()
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{
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m_ResendTimer.cancel ();
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m_ResendTimer.expires_from_now (boost::posix_time::seconds(RESEND_INTERVAL));
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auto s = m_Session.shared_from_this();
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m_ResendTimer.async_wait ([s](const boost::system::error_code& ecode)
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{ s->m_Data.HandleResendTimer (ecode); });
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}
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void SSUData::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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uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
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int numResent = 0;
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for (auto it = m_SentMessages.begin (); it != m_SentMessages.end ();)
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{
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if (ts >= it->second->nextResendTime)
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{
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if (it->second->numResends < MAX_NUM_RESENDS)
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{
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for (auto& f: it->second->fragments)
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if (f)
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{
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try
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{
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m_Session.Send (f->buf, f->len); // resend
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numResent++;
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}
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catch (boost::system::system_error& ec)
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{
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LogPrint (eLogWarning, "SSU: Can't resend message ", it->first, " data fragment: ", ec.what ());
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}
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}
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it->second->numResends++;
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it->second->nextResendTime += it->second->numResends*RESEND_INTERVAL;
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++it;
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}
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else
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{
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LogPrint (eLogInfo, "SSU: message ", it->first, " has not been ACKed after ", MAX_NUM_RESENDS, " attempts, deleted");
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it = m_SentMessages.erase (it);
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}
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}
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else
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++it;
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}
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if (m_SentMessages.empty ()) return; // nothing to resend
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if (numResent < MAX_OUTGOING_WINDOW_SIZE)
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ScheduleResend ();
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else
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{
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LogPrint (eLogError, "SSU: resend window exceeds max size. Session terminated");
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m_Session.Close ();
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}
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}
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}
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void SSUData::ScheduleIncompleteMessagesCleanup ()
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{
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m_IncompleteMessagesCleanupTimer.cancel ();
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m_IncompleteMessagesCleanupTimer.expires_from_now (boost::posix_time::seconds(INCOMPLETE_MESSAGES_CLEANUP_TIMEOUT));
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auto s = m_Session.shared_from_this();
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m_IncompleteMessagesCleanupTimer.async_wait ([s](const boost::system::error_code& ecode)
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{ s->m_Data.HandleIncompleteMessagesCleanupTimer (ecode); });
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}
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void SSUData::HandleIncompleteMessagesCleanupTimer (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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uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
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for (auto it = m_IncompleteMessages.begin (); it != m_IncompleteMessages.end ();)
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{
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if (ts > it->second->lastFragmentInsertTime + INCOMPLETE_MESSAGES_CLEANUP_TIMEOUT)
|
|
{
|
|
LogPrint (eLogWarning, "SSU: message ", it->first, " was not completed in ", INCOMPLETE_MESSAGES_CLEANUP_TIMEOUT, " seconds, deleted");
|
|
it = m_IncompleteMessages.erase (it);
|
|
}
|
|
else
|
|
++it;
|
|
}
|
|
// decay
|
|
if (m_ReceivedMessages.size () > MAX_NUM_RECEIVED_MESSAGES ||
|
|
i2p::util::GetSecondsSinceEpoch () > m_LastMessageReceivedTime + DECAY_INTERVAL)
|
|
m_ReceivedMessages.clear ();
|
|
|
|
ScheduleIncompleteMessagesCleanup ();
|
|
}
|
|
}
|
|
}
|
|
}
|