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Code Issues Releases Activity

send relay response

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orignal 2022-04-22 20:34:19 -04:00
parent e10ca637da
commit 751da92c13
2 changed files with 55 additions and 11 deletions
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64
libi2pd/SSU2.cpp
View File

@ -1045,6 +1045,12 @@ namespace transport
void SSU2Session::HandleRelayIntro (const uint8_t * buf, size_t len)
{
// we are Charlie
auto r = i2p::data::netdb.FindRouter (buf + 1); // Alice
if (!r)
{
LogPrint (eLogError, "SSU2: RelayIntro unknown router to introduce");
return;
}
SignedData s;
s.Insert ((const uint8_t *)"RelayRequestData", 16); // prologue
s.Insert (GetRemoteIdentity ()->GetIdentHash (), 32); // bhash
@ -1052,14 +1058,19 @@ namespace transport
s.Insert (buf + 33, 14); // nonce, relay tag, timestamp, ver, asz
uint8_t asz = buf[46];
s.Insert (buf + 47, asz); // Alice Port, Alice IP
if (!s.Verify (GetRemoteIdentity (), buf + 47 + asz))
if (!s.Verify (r->GetIdentity (), buf + 47 + asz))
{
LogPrint (eLogWarning, "SSU2: RelayIntro signature verification failed");
return; // TODO: send relay response
}
// TODO: send RelayResponse to Bob
// send relay response to Bob
uint8_t payload[SSU2_MTU];
size_t payloadSize = CreateRelayResponseBlock (payload, SSU2_MTU, bufbe32toh (buf + 33), bufbe32toh (buf + 37));
payloadSize += CreatePaddingBlock (payload + payloadSize, SSU2_MTU - payloadSize);
SendData (payload, payloadSize);
// send HolePunch
boost::asio::ip::udp::endpoint ep;
if (ExtractEndpoint (buf + 47, asz, ep))
m_Server.SendHolePunch (ep);
@ -1089,28 +1100,36 @@ namespace transport
return true;
}
size_t SSU2Session::CreateAddressBlock (const boost::asio::ip::udp::endpoint& ep, uint8_t * buf, size_t len)
size_t SSU2Session::CreateEndpoint (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& ep)
{
if (len < 9) return 0;
buf[0] = eSSU2BlkAddress;
htobe16buf (buf + 3, ep.port ());
if (len < 6) return 0;
htobe16buf (buf, ep.port ());
size_t size = 0;
if (ep.address ().is_v4 ())
{
memcpy (buf + 5, ep.address ().to_v4 ().to_bytes ().data (), 4);
memcpy (buf + 2, ep.address ().to_v4 ().to_bytes ().data (), 4);
size = 6;
}
else if (ep.address ().is_v6 ())
{
if (len < 21) return 0;
memcpy (buf + 5, ep.address ().to_v6 ().to_bytes ().data (), 16);
if (len < 18) return 0;
memcpy (buf + 2, ep.address ().to_v6 ().to_bytes ().data (), 16);
size = 18;
}
else
{
LogPrint (eLogWarning, "SSU2: Wrong address type ", ep.address ().to_string ());
return 0;
}
}
return size;
}
size_t SSU2Session::CreateAddressBlock (const boost::asio::ip::udp::endpoint& ep, uint8_t * buf, size_t len)
{
if (len < 9) return 0;
buf[0] = eSSU2BlkAddress;
size_t size = CreateEndpoint (buf + 3, len - 3, ep);
if (!size) return 0;
htobe16buf (buf + 1, size);
return size + 3;
}
@ -1240,6 +1259,29 @@ namespace transport
memcpy (buf + 36, introData, introDataLen);
return payloadSize + 3;
}
size_t SSU2Session::CreateRelayResponseBlock (uint8_t * buf, size_t len, uint32_t nonce, uint32_t relayTag)
{
buf[0] = eSSU2BlkRelayResponse;
buf[3] = 0; // flag
buf[4] = 0; // code, accept
htobe32buf (buf + 5, nonce); // nonce
htobe32buf (buf + 9, relayTag); // relayTag
htobe32buf (buf + 13, i2p::util::GetSecondsSinceEpoch ()); // timestamp
buf[17] = 2; // ver
size_t csz = CreateEndpoint (buf + 19, len - 19, boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port));
if (!csz) return 0;
buf[18] = csz; // csz
// signature
SignedData s;
s.Insert ((const uint8_t *)"RelayAgreementOK", 16); // prologue
s.Insert (GetRemoteIdentity ()->GetIdentHash (), 32); // bhash
s.Insert (buf + 9, 10 + csz); // relay tag, timestamp, ver, csz and Charlie's endpoint
s.Sign (i2p::context.GetPrivateKeys (), buf + 19 + csz);
size_t payloadSize = 16 + csz + i2p::context.GetIdentity ()->GetSignatureLen ();
htobe16buf (buf + 1, payloadSize); // size
return payloadSize + 3;
}
std::shared_ptr<const i2p::data::RouterInfo> SSU2Session::ExtractRouterInfo (const uint8_t * buf, size_t size)
{

2
libi2pd/SSU2.h
View File

@ -179,6 +179,7 @@ namespace transport
void HandleAck (const uint8_t * buf, size_t len);
void HandleAckRange (uint32_t firstPacketNum, uint32_t lastPacketNum);
bool ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep);
size_t CreateEndpoint (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& ep);
std::shared_ptr<const i2p::data::RouterInfo> ExtractRouterInfo (const uint8_t * buf, size_t size);
void CreateNonce (uint64_t seqn, uint8_t * nonce);
bool UpdateReceivePacketNum (uint32_t packetNum); // for Ack, returns false if duplicate
@ -195,6 +196,7 @@ namespace transport
size_t CreateFirstFragmentBlock (uint8_t * buf, size_t len, std::shared_ptr<I2NPMessage> msg);
size_t CreateFollowOnFragmentBlock (uint8_t * buf, size_t len, std::shared_ptr<I2NPMessage> msg, uint8_t& fragmentNum, uint32_t msgID);
size_t CreateRelayIntroBlock (uint8_t * buf, size_t len, const uint8_t * introData, size_t introDataLen);
size_t CreateRelayResponseBlock (uint8_t * buf, size_t len, uint32_t nonce, uint32_t relayTag); // Charlie
private: