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create and handle Address block

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orignal 2022-03-16 13:13:31 -04:00
parent 33645d7f09
commit 7473d8c9aa
2 changed files with 76 additions and 6 deletions
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80
libi2pd/SSU2.cpp
View File

@ -54,7 +54,7 @@ namespace transport
m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair ();
Header header;
uint8_t headerX[48], payload[48];
uint8_t headerX[48], payload[40];
// fill packet
RAND_bytes ((uint8_t *)&m_DestConnID, 8);
header.h.connID = m_DestConnID; // dest id
@ -72,7 +72,7 @@ namespace transport
htobe16buf (payload + 1, 4);
htobe32buf (payload + 3, i2p::util::GetSecondsSinceEpoch ());
size_t payloadSize = 7;
uint8_t paddingSize = (rand () & 0x0F) + 9; // 9 - 24
uint8_t paddingSize = (rand () & 0x0F) + 1; // 1 - 16
payload[payloadSize] = eSSU2BlkPadding;
htobe16buf (payload + payloadSize + 1, paddingSize);
payloadSize += paddingSize + 3;
@ -89,7 +89,7 @@ namespace transport
header.ll[0] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 24));
header.ll[1] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 12));
i2p::crypto::ChaCha20 (headerX, 48, m_Address->i, nonce, headerX);
m_NoiseState->MixHash (payload, 32); // h = SHA256(h || 32 byte encrypted payload from Session Request) for SessionCreated
m_NoiseState->MixHash (payload, 24); // h = SHA256(h || 24 byte encrypted payload from Session Request) for SessionCreated
// send
m_Server.AddPendingOutgoingSession (boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port), shared_from_this ());
m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint);
@ -120,6 +120,7 @@ namespace transport
m_NoiseState->MixKey (sharedSecret);
// decrypt
uint8_t * payload = buf + 64;
m_NoiseState->MixHash (payload, 24); // h = SHA256(h || 24 byte encrypted payload from Session Request) for SessionCreated
if (!i2p::crypto::AEADChaCha20Poly1305 (payload, len - 80, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, len - 80, false))
{
LogPrint (eLogWarning, "SSU2: SessionRequest AEAD verification failed ");
@ -139,8 +140,7 @@ namespace transport
// fill packet
Header header;
uint8_t headerX[48], payload[1200]; // TODO: correct payload size
size_t payloadSize = 8;
uint8_t headerX[48], payload[64];
header.h.connID = m_DestConnID; // dest id
memset (header.h.packetNum, 0, 4);
header.h.type = eSSU2SessionCreated;
@ -150,6 +150,19 @@ namespace transport
memcpy (headerX, &m_SourceConnID, 8); // source id
RAND_bytes (headerX + 8, 8); // token
memcpy (headerX + 16, m_EphemeralKeys->GetPublicKey (), 32); // Y
// payload
payload[0] = eSSU2BlkDateTime;
htobe16buf (payload + 1, 4);
htobe32buf (payload + 3, i2p::util::GetSecondsSinceEpoch ());
size_t payloadSize = 7;
payloadSize += CreateAddressBlock (m_RemoteEndpoint, payload, 57);
uint8_t paddingSize = rand () & 0x0F; // 0 - 15
if (paddingSize)
{
payload[payloadSize] = eSSU2BlkPadding;
htobe16buf (payload + payloadSize + 1, paddingSize);
payloadSize += paddingSize + 3;
}
// KDF for SessionCreated
m_NoiseState->MixHash ( { {header.buf, 16}, {headerX, 16} } ); // h = SHA256(h || header)
m_NoiseState->MixHash (headerX + 16, 32); // h = SHA256(h || bepk);
@ -253,7 +266,12 @@ namespace transport
case eSSU2BlkAck:
break;
case eSSU2BlkAddress:
break;
{
boost::asio::ip::udp::endpoint ep;
if (ExtractEndpoint (buf + offset, size, ep))
LogPrint (eLogInfo, "SSU2: Our external address is ", ep);
break;
}
case eSSU2BlkIntroKey:
break;
case eSSU2BlkRelayTagRequest:
@ -277,6 +295,56 @@ namespace transport
offset += size;
}
}
bool SSU2Session::ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep)
{
if (size < 2) return false;
int port = bufbe16toh (buf);
if (size == 6)
{
boost::asio::ip::address_v4::bytes_type bytes;
memcpy (bytes.data (), buf + 2, 4);
ep = boost::asio::ip::udp::endpoint (boost::asio::ip::address_v4 (bytes), port);
}
else if (size == 18)
{
boost::asio::ip::address_v6::bytes_type bytes;
memcpy (bytes.data (), buf + 2, 16);
ep = boost::asio::ip::udp::endpoint (boost::asio::ip::address_v6 (bytes), port);
}
else
{
LogPrint (eLogWarning, "SSU2: Address size ", int(size), " is not supported");
return false;
}
return true;
}
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;
htobe16buf (buf + 3, ep.port ());
size_t size = 0;
if (ep.address ().is_v4 ())
{
memcpy (buf + 5, 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);
size = 18;
}
else
{
LogPrint (eLogWarning, "SSU2: Wrong address type ", ep.address ().to_string ());
return 0;
}
htobe16buf (buf + 1, size);
return size + 3;
}
SSU2Server::SSU2Server ():
RunnableServiceWithWork ("SSU2"), m_Socket (GetService ())

2
libi2pd/SSU2.h
View File

@ -94,6 +94,8 @@ namespace transport
void SendSessionCreated (const uint8_t * X);
void HandlePayload (const uint8_t * buf, size_t len);
bool ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep);
size_t CreateAddressBlock (const boost::asio::ip::udp::endpoint& ep, uint8_t * buf, size_t len);
private: