void HandleTunnelGatewayMsg (I2NPMessage * msg)
{
TunnelGatewayHeader * header = (TunnelGatewayHeader *)msg->GetPayload ();
uint32_t tunnelID = be32toh(header->tunnelID);
uint16_t len = be16toh(header->length);
// we make payload as new I2NP message to send
msg->offset += sizeof (I2NPHeader) + sizeof (TunnelGatewayHeader);
msg->len = msg->offset + len;
LogPrint ("TunnelGateway of ", (int)len, " bytes for tunnel ", (unsigned int)tunnelID, ". Msg type ", (int)msg->GetHeader()->typeID);
if (msg->GetHeader()->typeID == eI2NPDatabaseStore ||
msg->GetHeader()->typeID == eI2NPDatabaseSearchReply)
{
// transit DatabaseStore my contain new/updated RI
// or DatabaseSearchReply with new routers
auto ds = NewI2NPMessage ();
*ds = *msg;
i2p::data::netdb.PostI2NPMsg (ds);
}
i2p::tunnel::TransitTunnel * tunnel = i2p::tunnel::tunnels.GetTransitTunnel (tunnelID);
if (tunnel)
tunnel->SendTunnelDataMsg (msg);
else
{
LogPrint ("Tunnel ", (unsigned int)tunnelID, " not found");
i2p::DeleteI2NPMessage (msg);
}
}
void TunnelGatewayBuffer::CreateCurrentTunnelDataMessage ()
{
m_CurrentTunnelDataMsg = NewI2NPMessage ();
// we reserve space for padding
m_CurrentTunnelDataMsg->offset += TUNNEL_DATA_MSG_SIZE + sizeof (I2NPHeader);
m_CurrentTunnelDataMsg->len = m_CurrentTunnelDataMsg->offset;
m_RemainingSize = TUNNEL_DATA_MAX_PAYLOAD_SIZE;
}
I2NPMessage * CreateI2NPMessage (const uint8_t * buf, int len, i2p::tunnel::InboundTunnel * from)
{
I2NPMessage * msg = NewI2NPMessage ();
memcpy (msg->GetBuffer (), buf, len);
msg->len = msg->offset + len;
msg->from = from;
return msg;
}
I2NPMessage * CreateTunnelDataMsg (const uint8_t * buf)
{
I2NPMessage * msg = NewI2NPMessage ();
memcpy (msg->GetPayload (), buf, i2p::tunnel::TUNNEL_DATA_MSG_SIZE);
msg->len += i2p::tunnel::TUNNEL_DATA_MSG_SIZE;
FillI2NPMessageHeader (msg, eI2NPTunnelData);
return msg;
}
I2NPMessage * CreateI2NPMessage (I2NPMessageType msgType, const uint8_t * buf, int len, uint32_t replyMsgID)
{
I2NPMessage * msg = NewI2NPMessage (len);
memcpy (msg->GetPayload (), buf, len);
msg->len += len;
FillI2NPMessageHeader (msg, msgType, replyMsgID);
return msg;
}
std::shared_ptr<I2NPMessage> CreateI2NPMessage (I2NPMessageType msgType, const uint8_t * buf, size_t len, uint32_t replyMsgID)
{
auto msg = NewI2NPMessage (len);
if (msg->Concat (buf, len) < len)
LogPrint (eLogError, "I2NP: message length ", len, " exceeds max length ", msg->maxLen);
msg->FillI2NPMessageHeader (msgType, replyMsgID);
return msg;
}
I2NPMessage * CreateTunnelDataMsg (uint32_t tunnelID, const uint8_t * payload)
{
I2NPMessage * msg = NewI2NPMessage ();
memcpy (msg->GetPayload () + 4, payload, i2p::tunnel::TUNNEL_DATA_MSG_SIZE - 4);
*(uint32_t *)(msg->GetPayload ()) = htobe32 (tunnelID);
msg->len += i2p::tunnel::TUNNEL_DATA_MSG_SIZE;
FillI2NPMessageHeader (msg, eI2NPTunnelData);
return msg;
}
I2NPMessage * CreateTunnelGatewayMsg (uint32_t tunnelID, const uint8_t * buf, size_t len)
{
I2NPMessage * msg = NewI2NPMessage (len);
TunnelGatewayHeader * header = (TunnelGatewayHeader *)msg->GetPayload ();
header->tunnelID = htobe32 (tunnelID);
header->length = htobe16 (len);
memcpy (msg->GetPayload () + sizeof (TunnelGatewayHeader), buf, len);
msg->len += sizeof (TunnelGatewayHeader) + len;
FillI2NPMessageHeader (msg, eI2NPTunnelGateway);
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> CreateI2NPMessage (const uint8_t * buf, size_t len, std::shared_ptr<i2p::tunnel::InboundTunnel> from)
{
auto msg = NewI2NPMessage ();
if (msg->offset + len < msg->maxLen)
{
memcpy (msg->GetBuffer (), buf, len);
msg->len = msg->offset + len;
msg->from = from;
}
else
LogPrint (eLogError, "I2NP: message length ", len, " exceeds max length");
return msg;
}
I2NPMessage * DatagramDestination::CreateDataMessage (const uint8_t * payload, size_t len)
{
I2NPMessage * msg = NewI2NPMessage ();
CryptoPP::Gzip compressor; // default level
compressor.Put (payload, len);
compressor.MessageEnd();
int size = compressor.MaxRetrievable ();
uint8_t * buf = msg->GetPayload ();
*(uint32_t *)buf = htobe32 (size); // length
buf += 4;
compressor.Get (buf, size);
memset (buf + 4, 0, 4); // source and destination are zeroes
buf[9] = i2p::client::PROTOCOL_TYPE_DATAGRAM; // datagram protocol
msg->len += size + 4;
FillI2NPMessageHeader (msg, eI2NPData);
return msg;
}
I2NPMessage * CreateTunnelGatewayMsg (uint32_t tunnelID, I2NPMessageType msgType,
const uint8_t * buf, size_t len, uint32_t replyMsgID)
{
I2NPMessage * msg = NewI2NPMessage (len);
size_t gatewayMsgOffset = sizeof (I2NPHeader) + sizeof (TunnelGatewayHeader);
msg->offset += gatewayMsgOffset;
msg->len += gatewayMsgOffset;
memcpy (msg->GetPayload (), buf, len);
msg->len += len;
FillI2NPMessageHeader (msg, msgType, replyMsgID); // create content message
len = msg->GetLength ();
msg->offset -= gatewayMsgOffset;
TunnelGatewayHeader * header = (TunnelGatewayHeader *)msg->GetPayload ();
header->tunnelID = htobe32 (tunnelID);
header->length = htobe16 (len);
FillI2NPMessageHeader (msg, eI2NPTunnelGateway); // gateway message
return msg;
}
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, 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> 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;
}
std::shared_ptr<I2NPMessage> NewI2NPMessage (size_t len)
{
return (len < I2NP_MAX_SHORT_MESSAGE_SIZE/2) ? NewI2NPShortMessage () : NewI2NPMessage ();
}
I2NPMessage * NewI2NPMessage (size_t len)
{
return (len < I2NP_MAX_SHORT_MESSAGE_SIZE/2) ? NewI2NPShortMessage () : NewI2NPMessage ();
}
I2NPMessage * TunnelGatewayBuffer::CreateNextTunnelMessage (int& ind)
{
int cnt = m_I2NPMsgs.size ();
if (ind > cnt - 1) return nullptr; // no more messages
// calculate payload size
size_t size = 0;
int i = ind;
if (m_NextOffset)
{
size = m_I2NPMsgs[i]->data->GetLength () - m_NextOffset + 7; // including follow-on header
i++;
}
while (i < cnt)
{
auto msg = m_I2NPMsgs[i];
size += msg->totalLen;
if (size >= TUNNEL_DATA_MAX_PAYLOAD_SIZE)
{
size = TUNNEL_DATA_MAX_PAYLOAD_SIZE;
break;
}
if (msg->isFragmented) break;
i++;
}
I2NPMessage * tunnelMsg = NewI2NPMessage ();
uint8_t * buf = tunnelMsg->GetPayload ();
*(uint32_t *)(buf) = htobe32 (m_TunnelID);
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
rnd.GenerateBlock (buf + 4, 16); // original IV
memcpy (buf + TUNNEL_DATA_MSG_SIZE, buf + 4, 16); // copy IV for checksum
size_t zero = TUNNEL_DATA_MSG_SIZE - size -1;
buf[zero] = 0; // zero
size_t s = 0;
while (ind < cnt)
{
auto msg = m_I2NPMsgs[ind];
if (m_NextOffset)
{
s += CreateFollowOnFragment (msg, buf + zero + 1 + s, size - s);
m_NextOffset = 0; // TODO:
}
else
{
s += CreateFirstFragment (msg, buf + zero + 1 + s, size - s);
if (msg->isFragmented) break; // payload is full, but we stay at the same message
}
ind++;
if (s >= size) break; // payload is full but we moved to next message
}
if (s != size)
{
LogPrint ("TunnelData payload size mismatch ", s, "!=", size);
return nullptr;
}
uint8_t hash[32];
CryptoPP::SHA256().CalculateDigest(hash, buf+zero+1, size+16);
memcpy (buf+20, hash, 4); // checksum
if (zero > 24)
memset (buf+24, 1, zero-24); // padding TODO: fill with random data
tunnelMsg->len += TUNNEL_DATA_MSG_SIZE;
// we can't fill message header yet because encryption is required
return tunnelMsg;
}
std::shared_ptr<I2NPMessage> GarlicRoutingSession::WrapSingleMessage (std::shared_ptr<const I2NPMessage> msg)
{
auto m = NewI2NPMessage ();
m->Align (12); // in order to get buf aligned to 16 (12 + 4)
size_t len = 0;
uint8_t * buf = m->GetPayload () + 4; // 4 bytes for length
// find non-expired tag
bool tagFound = false;
SessionTag tag;
if (m_NumTags > 0)
{
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
while (!m_SessionTags.empty ())
{
if (ts < m_SessionTags.front ().creationTime + OUTGOING_TAGS_EXPIRATION_TIMEOUT)
{
tag = m_SessionTags.front ();
m_SessionTags.pop_front (); // use same tag only once
tagFound = true;
break;
}
else
m_SessionTags.pop_front (); // remove expired tag
}
}
// create message
if (!tagFound) // new session
{
LogPrint (eLogInfo, "Garlic: No tags available, will use ElGamal");
if (!m_Destination)
{
LogPrint (eLogError, "Garlic: Can't use ElGamal for unknown destination");
return nullptr;
}
// create ElGamal block
ElGamalBlock elGamal;
memcpy (elGamal.sessionKey, m_SessionKey, 32);
RAND_bytes (elGamal.preIV, 32); // Pre-IV
uint8_t iv[32]; // IV is first 16 bytes
SHA256(elGamal.preIV, 32, iv);
BN_CTX * ctx = BN_CTX_new ();
m_Destination->Encrypt ((uint8_t *)&elGamal, buf, ctx);
BN_CTX_free (ctx);
m_Encryption.SetIV (iv);
buf += 514;
len += 514;
}
else // existing session
{
// session tag
memcpy (buf, tag, 32);
uint8_t iv[32]; // IV is first 16 bytes
SHA256(tag, 32, iv);
m_Encryption.SetIV (iv);
buf += 32;
len += 32;
}
// AES block
len += CreateAESBlock (buf, msg);
htobe32buf (m->GetPayload (), len);
m->len += len + 4;
m->FillI2NPMessageHeader (eI2NPGarlic);
return m;
}
I2NPMessage * CreateDatabaseLookupMsg (const uint8_t * key, const uint8_t * from,
uint32_t replyTunnelID, bool exploratory, std::set<i2p::data::IdentHash> * excludedPeers,
bool encryption, i2p::tunnel::TunnelPool * pool)
{
I2NPMessage * m = NewI2NPMessage ();
uint8_t * buf = m->GetPayload ();
memcpy (buf, key, 32); // key
buf += 32;
memcpy (buf, from, 32); // from
buf += 32;
if (replyTunnelID)
{
*buf = encryption ? 0x03: 0x01; // set delivery flag
*(uint32_t *)(buf+1) = htobe32 (replyTunnelID);
buf += 5;
}
else
{
encryption = false; // encryption can we set for tunnels only
*buf = 0; // flag
buf++;
}
if (exploratory)
{
*(uint16_t *)buf = htobe16 (1); // one exlude record
buf += 2;
// reply with non-floodfill routers only
memset (buf, 0, 32);
buf += 32;
}
else
{
if (excludedPeers)
{
int cnt = excludedPeers->size ();
*(uint16_t *)buf = htobe16 (cnt);
buf += 2;
for (auto& it: *excludedPeers)
{
memcpy (buf, it, 32);
buf += 32;
}
}
else
{
// nothing to exclude
*(uint16_t *)buf = htobe16 (0);
buf += 2;
}
}
if (encryption)
{
// session key and tag for reply
auto& rnd = i2p::context.GetRandomNumberGenerator ();
rnd.GenerateBlock (buf, 32); // key
buf[32] = 1; // 1 tag
rnd.GenerateBlock (buf + 33, 32); // tag
if (pool)
pool->GetLocalDestination ().SubmitSessionKey (buf, buf + 33); // introduce new key-tag to garlic engine
else
LogPrint ("Destination for encrypteed reply not specified");
buf += 65;
}
m->len += (buf - m->GetPayload ());
FillI2NPMessageHeader (m, eI2NPDatabaseLookup);
return m;
}
