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handle out-of-sequence tunnel fragments

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orignal 2014-09-10 21:31:32 -04:00
parent 5abd4021c4
commit 26c629a7d8
2 changed files with 65 additions and 13 deletions
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67
TunnelEndpoint.cpp
View File

@ -15,6 +15,8 @@ namespace tunnel
{
for (auto it: m_IncompleteMessages)
i2p::DeleteI2NPMessage (it.second.data);
for (auto it: m_OutOfSequenceFragments)
i2p::DeleteI2NPMessage (it.second.data);
}
void TunnelEndpoint::HandleDecryptedTunnelDataMsg (I2NPMessage * msg)
@ -120,6 +122,7 @@ namespace tunnel
{
m.nextFragmentNum = 1;
m_IncompleteMessages[msgID] = m;
HandleOutOfSequenceFragment (msgID, m);
}
else
{
@ -148,40 +151,78 @@ namespace tunnel
auto it = m_IncompleteMessages.find (msgID);
if (it != m_IncompleteMessages.end())
{
if (m.nextFragmentNum == it->second.nextFragmentNum)
auto& msg = it->second;
if (m.nextFragmentNum == msg.nextFragmentNum)
{
I2NPMessage * incompleteMessage = it->second.data;
if (incompleteMessage->len + size < I2NP_MAX_MESSAGE_SIZE) // check if messega is not too long
if (msg.data->len + size < I2NP_MAX_MESSAGE_SIZE) // check if messega is not too long
{
memcpy (incompleteMessage->buf + incompleteMessage->len, fragment, size); // concatenate fragment
incompleteMessage->len += size;
memcpy (msg.data->buf + msg.data->len, fragment, size); // concatenate fragment
msg.data->len += size;
if (isLastFragment)
{
// message complete
HandleNextMessage (it->second);
HandleNextMessage (msg);
m_IncompleteMessages.erase (it);
}
else
it->second.nextFragmentNum++;
{
msg.nextFragmentNum++;
HandleOutOfSequenceFragment (msgID, msg);
}
}
else
{
LogPrint ("Fragment ", m.nextFragmentNum, " of message ", msgID, "exceeds max I2NP message size. Message dropped");
i2p::DeleteI2NPMessage (it->second.data);
i2p::DeleteI2NPMessage (msg.data);
m_IncompleteMessages.erase (it);
}
i2p::DeleteI2NPMessage (m.data);
}
else
{
LogPrint ("Unexpected fragment ", m.nextFragmentNum, " instead ", it->second.nextFragmentNum, " of message ", msgID, ". Discarded");
i2p::DeleteI2NPMessage (it->second.data);
m_IncompleteMessages.erase (it); // TODO: store unexpected fragment for a while
LogPrint ("Unexpected fragment ", (int)m.nextFragmentNum, " instead ", (int)msg.nextFragmentNum, " of message ", msgID, ". Saved");
AddOutOfSequenceFragment (msgID, m.nextFragmentNum, isLastFragment, m.data);
}
}
else
LogPrint ("First fragment of message ", msgID, " not found. Discarded");
{
LogPrint ("First fragment of message ", msgID, " not found. Saved");
AddOutOfSequenceFragment (msgID, m.nextFragmentNum, isLastFragment, m.data);
}
}
i2p::DeleteI2NPMessage (m.data);
void TunnelEndpoint::AddOutOfSequenceFragment (uint32_t msgID, uint8_t fragmentNum, bool isLastFragment, I2NPMessage * data)
{
auto it = m_OutOfSequenceFragments.find (msgID);
if (it == m_OutOfSequenceFragments.end ())
m_OutOfSequenceFragments.insert (std::pair<uint32_t, Fragment> (msgID, {fragmentNum, isLastFragment, data}));
else
i2p::DeleteI2NPMessage (data);
}
void TunnelEndpoint::HandleOutOfSequenceFragment (uint32_t msgID, TunnelMessageBlockEx& msg)
{
auto it = m_OutOfSequenceFragments.find (msgID);
if (it != m_OutOfSequenceFragments.end ())
{
if (it->second.fragmentNum == msg.nextFragmentNum)
{
LogPrint ("Out-of-sequence fragment ", (int)it->second.fragmentNum, " of message ", msgID, " found");
auto size = it->second.data->GetLength ();
memcpy (msg.data->buf + msg.data->len, it->second.data->GetBuffer (), size); // concatenate out-of-sync fragment
msg.data->len += size;
if (it->second.isLastFragment)
{
// message complete
HandleNextMessage (msg);
m_IncompleteMessages.erase (msgID);
}
else
msg.nextFragmentNum++;
i2p::DeleteI2NPMessage (it->second.data);
m_OutOfSequenceFragments.erase (it);
}
}
}
void TunnelEndpoint::HandleNextMessage (const TunnelMessageBlock& msg)

11
TunnelEndpoint.h
View File

@ -17,6 +17,13 @@ namespace tunnel
{
uint8_t nextFragmentNum;
};
struct Fragment
{
uint8_t fragmentNum;
bool isLastFragment;
I2NPMessage * data;
};
public:
@ -30,10 +37,14 @@ namespace tunnel
void HandleFollowOnFragment (uint32_t msgID, bool isLastFragment, const TunnelMessageBlockEx& m);
void HandleNextMessage (const TunnelMessageBlock& msg);
void AddOutOfSequenceFragment (uint32_t msgID, uint8_t fragmentNum, bool isLastFragment, I2NPMessage * data);
void HandleOutOfSequenceFragment (uint32_t msgID, TunnelMessageBlockEx& msg);
private:
std::map<uint32_t, TunnelMessageBlockEx> m_IncompleteMessages;
std::map<uint32_t, Fragment> m_OutOfSequenceFragments;
bool m_IsInbound;
size_t m_NumReceivedBytes;
};