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create relay tag and relay request block

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orignal 2022-04-21 15:47:36 -04:00
parent 3e0f5d231d
commit c5d9d71a8a
2 changed files with 92 additions and 1 deletions
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85
libi2pd/SSU2.cpp
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@ -32,7 +32,7 @@ namespace transport
TransportSession (in_RemoteRouter, SSU2_CONNECT_TIMEOUT),
m_Server (server), m_Address (addr), m_DestConnID (0), m_SourceConnID (0),
m_State (eSSU2SessionStateUnknown), m_SendPacketNum (0), m_ReceivePacketNum (0),
m_IsDataReceived (false), m_WindowSize (SSU2_MAX_WINDOW_SIZE)
m_IsDataReceived (false), m_WindowSize (SSU2_MAX_WINDOW_SIZE), m_RelayTag (0)
{
m_NoiseState.reset (new i2p::crypto::NoiseSymmetricState);
if (in_RemoteRouter && m_Address)
@ -70,6 +70,8 @@ namespace transport
m_State = eSSU2SessionStateTerminated;
transports.PeerDisconnected (shared_from_this ());
m_Server.RemoveSession (m_SourceConnID);
if (m_RelayTag)
m_Server.RemoveRelay (m_RelayTag);
m_SendQueue.clear ();
LogPrint (eLogDebug, "SSU2: Session terminated");
}
@ -338,6 +340,13 @@ namespace transport
htobe32buf (payload + 3, i2p::util::GetSecondsSinceEpoch ());
size_t payloadSize = 7;
payloadSize += CreateAddressBlock (m_RemoteEndpoint, payload + payloadSize, 64 - payloadSize);
if (m_RelayTag)
{
payload[payloadSize] = eSSU2BlkRelayTag;
htobe16buf (payload + payloadSize + 1, 4);
htobe32buf (payload + payloadSize + 3, m_RelayTag);
payloadSize += 7;
}
payloadSize += CreatePaddingBlock (payload + payloadSize, 64 - payloadSize);
// KDF for SessionCreated
m_NoiseState->MixHash ( { {header.buf, 16}, {headerX, 16} } ); // h = SHA256(h || header)
@ -810,6 +819,8 @@ namespace transport
Terminate ();
break;
case eSSU2BlkRelayRequest:
LogPrint (eLogDebug, "SSU2: RelayRequest");
HandleRelayRequest (buf + offset, size);
break;
case eSSU2BlkRelayResponse:
break;
@ -833,6 +844,13 @@ namespace transport
case eSSU2BlkIntroKey:
break;
case eSSU2BlkRelayTagRequest:
LogPrint (eLogDebug, "SSU2: RelayTagRequest");
HandleRelayRequest (buf + offset, size);
if (!m_RelayTag)
{
RAND_bytes ((uint8_t *)&m_RelayTag, 4);
m_Server.AddRelay (m_RelayTag, shared_from_this ());
}
break;
case eSSU2BlkRelayTag:
break;
@ -991,6 +1009,36 @@ namespace transport
break;
return isLast;
}
void SSU2Session::HandleRelayRequest (const uint8_t * buf, size_t len)
{
// we are Bob
uint32_t relayTag = bufbe32toh (buf + 5); // relay tag
auto session = m_Server.FindRelaySession (relayTag);
if (!session)
{
LogPrint (eLogWarning, "SSU2: Session with relay tag ", relayTag, " not found");
return; // TODO: send relay response
}
SignedData s;
s.Insert ((const uint8_t *)"RelayRequestData", 16); // prologue
s.Insert (i2p::context.GetIdentHash (), 32); // bhash
s.Insert (session->GetRemoteIdentity ()->GetIdentHash (), 32); // chash
s.Insert (buf + 1, 14); // nonce, relay tag, timestamp, ver, asz
uint8_t asz = buf[14];
s.Insert (buf + 15, asz + 2); // Alice IP, Alice Port
if (!s.Verify (GetRemoteIdentity (), buf + 17 + asz))
{
LogPrint (eLogWarning, "SSU2: RelayRequest signature verification failed");
return; // TODO: send relay response
}
// send relay intro to Charlie
uint8_t payload[SSU2_MTU];
size_t payloadSize = CreateRelayIntroBlock (payload, SSU2_MTU, buf + 1, len -1);
payloadSize += CreatePaddingBlock (payload + payloadSize, SSU2_MTU - payloadSize);
session->SendData (payload, payloadSize);
}
bool SSU2Session::ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep)
{
@ -1155,6 +1203,18 @@ namespace transport
msg->offset += msgLen;
return msgLen + 8;
}
size_t SSU2Session::CreateRelayIntroBlock (uint8_t * buf, size_t len, const uint8_t * introData, size_t introDataLen)
{
buf[0] = eSSU2BlkRelayIntro;
size_t payloadSize = 1/* flag */ + 32/* Alice router hash */ + introDataLen;
if (payloadSize + 3 > len) return 0;
htobe16buf (buf + 1, payloadSize); // size
buf[3] = 0; // flag
memcpy (buf + 4, GetRemoteIdentity ()->GetIdentHash (), 32); // Alice router hash
memcpy (buf + 36, introData, introDataLen);
return payloadSize + 3;
}
std::shared_ptr<const i2p::data::RouterInfo> SSU2Session::ExtractRouterInfo (const uint8_t * buf, size_t size)
{
@ -1441,6 +1501,29 @@ namespace transport
if (session)
m_PendingOutgoingSessions.emplace (session->GetRemoteEndpoint (), session);
}
void SSU2Server::AddRelay (uint32_t tag, std::shared_ptr<SSU2Session> relay)
{
m_Relays.emplace (tag, relay);
}
void SSU2Server::RemoveRelay (uint32_t tag)
{
m_Relays.erase (tag);
}
std::shared_ptr<SSU2Session> SSU2Server::FindRelaySession (uint32_t tag)
{
auto it = m_Relays.find (tag);
if (it != m_Relays.end ())
{
if (it->second->IsEstablished ())
return it->second;
else
m_Relays.erase (it);
}
return nullptr;
}
void SSU2Server::ProcessNextPacket (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
{