I2NPMessage * DatagramDestination::CreateDataMessage (const uint8_t * payload, size_t len, uint16_t fromPort, uint16_t toPort)
{
I2NPMessage * msg = NewI2NPMessage ();
CryptoPP::Gzip compressor; // default level
compressor.Put (payload, len);
compressor.MessageEnd();
int size = compressor.MaxRetrievable ();
uint8_t * buf = msg->GetPayload ();
htobe32buf (buf, size); // length
buf += 4;
compressor.Get (buf, size);
htobe16buf (buf + 4, fromPort); // source port
htobe16buf (buf + 6, toPort); // destination port
buf[9] = i2p::client::PROTOCOL_TYPE_DATAGRAM; // datagram protocol
msg->len += size + 4;
FillI2NPMessageHeader (msg, eI2NPData);
return msg;
}
std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg (uint32_t tunnelID, const uint8_t * buf, size_t len)
{
auto msg = NewI2NPMessage (len);
uint8_t * payload = msg->GetPayload ();
htobe32buf (payload + TUNNEL_GATEWAY_HEADER_TUNNELID_OFFSET, tunnelID);
htobe16buf (payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET, len);
msg->len += TUNNEL_GATEWAY_HEADER_SIZE;
if (msg->Concat (buf, len) < len)
LogPrint (eLogError, "I2NP: tunnel gateway buffer overflow ", msg->maxLen);
msg->FillI2NPMessageHeader (eI2NPTunnelGateway);
return msg;
}
std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg (uint32_t tunnelID, std::shared_ptr<I2NPMessage> msg)
{
if (msg->offset >= I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE)
{
// message is capable to be used without copying
uint8_t * payload = msg->GetBuffer () - TUNNEL_GATEWAY_HEADER_SIZE;
htobe32buf (payload + TUNNEL_GATEWAY_HEADER_TUNNELID_OFFSET, tunnelID);
int len = msg->GetLength ();
htobe16buf (payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET, len);
msg->offset -= (I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE);
msg->len = msg->offset + I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE +len;
msg->FillI2NPMessageHeader (eI2NPTunnelGateway);
return msg;
}
else
return CreateTunnelGatewayMsg (tunnelID, msg->GetBuffer (), msg->GetLength ());
}
std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg (uint32_t tunnelID, I2NPMessageType msgType,
const uint8_t * buf, size_t len, uint32_t replyMsgID)
{
auto msg = NewI2NPMessage (len);
size_t gatewayMsgOffset = I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE;
msg->offset += gatewayMsgOffset;
msg->len += gatewayMsgOffset;
if (msg->Concat (buf, len) < len)
LogPrint (eLogError, "I2NP: tunnel gateway buffer overflow ", msg->maxLen);
msg->FillI2NPMessageHeader (msgType, replyMsgID); // create content message
len = msg->GetLength ();
msg->offset -= gatewayMsgOffset;
uint8_t * payload = msg->GetPayload ();
htobe32buf (payload + TUNNEL_GATEWAY_HEADER_TUNNELID_OFFSET, tunnelID);
htobe16buf (payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET, len);
msg->FillI2NPMessageHeader (eI2NPTunnelGateway); // gateway message
return msg;
}
std::shared_ptr<I2NPMessage> CreateRouterInfoDatabaseLookupMsg (const uint8_t * key, const uint8_t * from,
uint32_t replyTunnelID, bool exploratory, std::set<i2p::data::IdentHash> * excludedPeers)
{
auto m = excludedPeers ? NewI2NPMessage () : NewI2NPShortMessage ();
uint8_t * buf = m->GetPayload ();
memcpy (buf, key, 32); // key
buf += 32;
memcpy (buf, from, 32); // from
buf += 32;
uint8_t flag = exploratory ? DATABASE_LOOKUP_TYPE_EXPLORATORY_LOOKUP : DATABASE_LOOKUP_TYPE_ROUTERINFO_LOOKUP;
if (replyTunnelID)
{
*buf = flag | DATABASE_LOOKUP_DELIVERY_FLAG; // set delivery flag
htobe32buf (buf+1, replyTunnelID);
buf += 5;
}
else
{
*buf = flag; // flag
buf++;
}
if (excludedPeers)
{
int cnt = excludedPeers->size ();
htobe16buf (buf, cnt);
buf += 2;
for (auto& it: *excludedPeers)
{
memcpy (buf, it, 32);
buf += 32;
}
}
else
{
// nothing to exclude
htobuf16 (buf, 0);
buf += 2;
}
m->len += (buf - m->GetPayload ());
m->FillI2NPMessageHeader (eI2NPDatabaseLookup);
return m;
}
std::shared_ptr<I2NPMessage> CreateDatabaseStoreMsg (std::shared_ptr<const i2p::data::RouterInfo> router, uint32_t replyToken)
{
if (!router) // we send own RouterInfo
router = context.GetSharedRouterInfo ();
auto m = NewI2NPShortMessage ();
uint8_t * payload = m->GetPayload ();
memcpy (payload + DATABASE_STORE_KEY_OFFSET, router->GetIdentHash (), 32);
payload[DATABASE_STORE_TYPE_OFFSET] = 0; // RouterInfo
htobe32buf (payload + DATABASE_STORE_REPLY_TOKEN_OFFSET, replyToken);
uint8_t * buf = payload + DATABASE_STORE_HEADER_SIZE;
if (replyToken)
{
memset (buf, 0, 4); // zero tunnelID means direct reply
buf += 4;
memcpy (buf, router->GetIdentHash (), 32);
buf += 32;
}
uint8_t * sizePtr = buf;
buf += 2;
m->len += (buf - payload); // payload size
i2p::data::GzipDeflator deflator;
size_t size = deflator.Deflate (router->GetBuffer (), router->GetBufferLen (), buf, m->maxLen -m->len);
if (size)
{
htobe16buf (sizePtr, size); // size
m->len += size;
}
else
m = nullptr;
if (m)
m->FillI2NPMessageHeader (eI2NPDatabaseStore);
return m;
}
std::shared_ptr<I2NPMessage> CreateLeaseSetDatabaseLookupMsg (const i2p::data::IdentHash& dest,
const std::set<i2p::data::IdentHash>& excludedFloodfills,
const i2p::tunnel::InboundTunnel * replyTunnel, const uint8_t * replyKey, const uint8_t * replyTag)
{
int cnt = excludedFloodfills.size ();
auto m = cnt > 0 ? NewI2NPMessage () : NewI2NPShortMessage ();
uint8_t * buf = m->GetPayload ();
memcpy (buf, dest, 32); // key
buf += 32;
memcpy (buf, replyTunnel->GetNextIdentHash (), 32); // reply tunnel GW
buf += 32;
*buf = DATABASE_LOOKUP_DELIVERY_FLAG | DATABASE_LOOKUP_ENCYPTION_FLAG | DATABASE_LOOKUP_TYPE_LEASESET_LOOKUP; // flags
htobe32buf (buf + 1, replyTunnel->GetNextTunnelID ()); // reply tunnel ID
buf += 5;
// excluded
htobe16buf (buf, cnt);
buf += 2;
if (cnt > 0)
{
for (auto& it: excludedFloodfills)
{
memcpy (buf, it, 32);
buf += 32;
}
}
// encryption
memcpy (buf, replyKey, 32);
buf[32] = 1; // 1 tag
memcpy (buf + 33, replyTag, 32);
buf += 65;
m->len += (buf - m->GetPayload ());
m->FillI2NPMessageHeader (eI2NPDatabaseLookup);
return m;
}
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
}
}
}
