void TunnelGatewayBuffer::PutI2NPMsg (const TunnelMessageBlock& block)
{
bool messageCreated = false;
if (!m_CurrentTunnelDataMsg)
{
CreateCurrentTunnelDataMessage ();
messageCreated = true;
}
// create delivery instructions
uint8_t di[43]; // max delivery instruction length is 43 for tunnel
size_t diLen = 1;// flag
if (block.deliveryType != eDeliveryTypeLocal) // tunnel or router
{
if (block.deliveryType == eDeliveryTypeTunnel)
{
htobe32buf (di + diLen, block.tunnelID);
diLen += 4; // tunnelID
}
memcpy (di + diLen, block.hash, 32);
diLen += 32; //len
}
di[0] = block.deliveryType << 5; // set delivery type
// create fragments
std::shared_ptr<I2NPMessage> msg = block.data;
auto fullMsgLen = diLen + msg->GetLength () + 2; // delivery instructions + payload + 2 bytes length
if (fullMsgLen <= m_RemainingSize)
{
// message fits. First and last fragment
htobe16buf (di + diLen, msg->GetLength ());
diLen += 2; // size
memcpy (m_CurrentTunnelDataMsg->buf + m_CurrentTunnelDataMsg->len, di, diLen);
memcpy (m_CurrentTunnelDataMsg->buf + m_CurrentTunnelDataMsg->len + diLen, msg->GetBuffer (), msg->GetLength ());
m_CurrentTunnelDataMsg->len += diLen + msg->GetLength ();
m_RemainingSize -= diLen + msg->GetLength ();
if (!m_RemainingSize)
CompleteCurrentTunnelDataMessage ();
}
else
{
if (!messageCreated) // check if we should complete previous message
{
auto numFollowOnFragments = fullMsgLen / TUNNEL_DATA_MAX_PAYLOAD_SIZE;
// length of bytes don't fit full tunnel message
// every follow-on fragment adds 7 bytes
auto nonFit = (fullMsgLen + numFollowOnFragments*7) % TUNNEL_DATA_MAX_PAYLOAD_SIZE;
if (!nonFit || nonFit > m_RemainingSize)
{
CompleteCurrentTunnelDataMessage ();
CreateCurrentTunnelDataMessage ();
}
}
if (diLen + 6 <= m_RemainingSize)
{
// delivery instructions fit
uint32_t msgID;
memcpy (&msgID, msg->GetHeader () + I2NP_HEADER_MSGID_OFFSET, 4); // in network bytes order
size_t size = m_RemainingSize - diLen - 6; // 6 = 4 (msgID) + 2 (size)
// first fragment
di[0] |= 0x08; // fragmented
htobuf32 (di + diLen, msgID);
diLen += 4; // Message ID
htobe16buf (di + diLen, size);
diLen += 2; // size
memcpy (m_CurrentTunnelDataMsg->buf + m_CurrentTunnelDataMsg->len, di, diLen);
memcpy (m_CurrentTunnelDataMsg->buf + m_CurrentTunnelDataMsg->len + diLen, msg->GetBuffer (), size);
m_CurrentTunnelDataMsg->len += diLen + size;
CompleteCurrentTunnelDataMessage ();
// follow on fragments
int fragmentNumber = 1;
while (size < msg->GetLength ())
{
CreateCurrentTunnelDataMessage ();
uint8_t * buf = m_CurrentTunnelDataMsg->GetBuffer ();
buf[0] = 0x80 | (fragmentNumber << 1); // frag
bool isLastFragment = false;
size_t s = msg->GetLength () - size;
if (s > TUNNEL_DATA_MAX_PAYLOAD_SIZE - 7) // 7 follow on instructions
s = TUNNEL_DATA_MAX_PAYLOAD_SIZE - 7;
else // last fragment
{
buf[0] |= 0x01;
isLastFragment = true;
}
htobuf32 (buf + 1, msgID); //Message ID
htobe16buf (buf + 5, s); // size
memcpy (buf + 7, msg->GetBuffer () + size, s);
m_CurrentTunnelDataMsg->len += s+7;
if (isLastFragment)
{
m_RemainingSize -= s+7;
if (!m_RemainingSize)
CompleteCurrentTunnelDataMessage ();
}
else
CompleteCurrentTunnelDataMessage ();
size += s;
fragmentNumber++;
}
}
else
{
// delivery instructions don't fit. Create new message
CompleteCurrentTunnelDataMessage ();
PutI2NPMsg (block);
// don't delete msg because it's taken care inside
}
}
}
void TunnelGatewayBuffer::PutI2NPMsg (const TunnelMessageBlock& block)
{
if (!m_CurrentTunnelDataMsg)
CreateCurrentTunnelDataMessage ();
// create delivery instructions
uint8_t di[43]; // max delivery instruction length is 43 for tunnel
size_t diLen = 1;// flag
if (block.deliveryType != eDeliveryTypeLocal) // tunnel or router
{
if (block.deliveryType == eDeliveryTypeTunnel)
{
*(uint32_t *)(di + diLen) = htobe32 (block.tunnelID);
diLen += 4; // tunnelID
}
memcpy (di + diLen, block.hash, 32);
diLen += 32; //len
}
di[0] = block.deliveryType << 5; // set delivery type
// create fragments
I2NPMessage * msg = block.data;
if (diLen + msg->GetLength () + 2<= m_RemainingSize)
{
// message fits. First and last fragment
*(uint16_t *)(di + diLen) = htobe16 (msg->GetLength ());
diLen += 2; // size
memcpy (m_CurrentTunnelDataMsg->buf + m_CurrentTunnelDataMsg->len, di, diLen);
memcpy (m_CurrentTunnelDataMsg->buf + m_CurrentTunnelDataMsg->len + diLen, msg->GetBuffer (), msg->GetLength ());
m_CurrentTunnelDataMsg->len += diLen + msg->GetLength ();
m_RemainingSize -= diLen + msg->GetLength ();
if (!m_RemainingSize)
CompleteCurrentTunnelDataMessage ();
DeleteI2NPMessage (msg);
}
else
{
if (diLen + 6 <= m_RemainingSize)
{
// delivery instructions fit
uint32_t msgID = msg->GetHeader ()->msgID;
size_t size = m_RemainingSize - diLen - 6; // 6 = 4 (msgID) + 2 (size)
// first fragment
di[0] |= 0x08; // fragmented
*(uint32_t *)(di + diLen) = htobe32 (msgID);
diLen += 4; // Message ID
*(uint16_t *)(di + diLen) = htobe16 (size);
diLen += 2; // size
memcpy (m_CurrentTunnelDataMsg->buf + m_CurrentTunnelDataMsg->len, di, diLen);
memcpy (m_CurrentTunnelDataMsg->buf + m_CurrentTunnelDataMsg->len + diLen, msg->GetBuffer (), size);
m_CurrentTunnelDataMsg->len += diLen + size;
CompleteCurrentTunnelDataMessage ();
// follow on fragments
int fragmentNumber = 1;
while (size < msg->GetLength ())
{
CreateCurrentTunnelDataMessage ();
uint8_t * buf = m_CurrentTunnelDataMsg->GetBuffer ();
buf[0] = 0x80 | (fragmentNumber << 1); // frag
bool isLastFragment = false;
size_t s = msg->GetLength () - size;
if (s > TUNNEL_DATA_MAX_PAYLOAD_SIZE - 7) // 7 follow on instructions
s = TUNNEL_DATA_MAX_PAYLOAD_SIZE - 7;
else // last fragment
{
buf[0] |= 0x01;
isLastFragment = true;
}
*(uint32_t *)(buf + 1) = htobe32 (msgID); //Message ID
*(uint16_t *)(buf + 5) = htobe16 (s); // size
memcpy (buf + 7, msg->GetBuffer () + size, s);
m_CurrentTunnelDataMsg->len += s+7;
if (isLastFragment)
{
m_RemainingSize -= s+7;
if (!m_RemainingSize)
CompleteCurrentTunnelDataMessage ();
}
else
CompleteCurrentTunnelDataMessage ();
size += s;
fragmentNumber++;
}
DeleteI2NPMessage (msg);
}
else
{
// delivery instructions don't fit. Create new message
CompleteCurrentTunnelDataMessage ();
PutI2NPMsg (block);
// don't delete msg because it's taken care inside
}
}
}
