diff --git a/SSU.cpp b/SSU.cpp index 5509b96e..12b9e49b 100644 --- a/SSU.cpp +++ b/SSU.cpp @@ -55,6 +55,10 @@ namespace ssu // session created ProcessSessionCreated (buf, len); break; + case eSessionStateCreatedSent: + // session confirmed + ProcessSessionConfirmed (buf, len); + break; default: LogPrint ("SSU state not implemented yet"); } @@ -88,12 +92,35 @@ namespace ssu { m_State = eSessionStateCreatedReceived; LogPrint ("Session created received"); - boost::asio::ip::address_v4 ourAddress (be32toh (*(uint32_t* )(buf + sizeof (SSUHeader) + 257))); - uint16_t ourPort = be16toh (*(uint16_t *)(buf + sizeof (SSUHeader) + 261)); - LogPrint ("Our external address is ", ourAddress.to_string (), ":", ourPort); + uint8_t * ourAddress = buf + sizeof (SSUHeader) + 257; + boost::asio::ip::address_v4 ourIP (be32toh (*(uint32_t* )(ourAddress))); + uint16_t ourPort = be16toh (*(uint16_t *)(ourAddress + 4)); + LogPrint ("Our external address is ", ourIP.to_string (), ":", ourPort); + uint32_t relayTag = be32toh (*(uint32_t *)(buf + sizeof (SSUHeader) + 263)); + SendSessionConfirmed (buf + sizeof (SSUHeader), ourAddress, relayTag); } } + void SSUSession::ProcessSessionConfirmed (uint8_t * buf, size_t len) + { + LogPrint ("Process session confirmed"); + if (Validate (buf, len, m_MacKey)) + { + Decrypt (buf, len, m_SessionKey); + SSUHeader * header = (SSUHeader *)buf; + if ((header->flag >> 4) == PAYLOAD_TYPE_SESSION_CONFIRMED) + { + m_State = eSessionStateConfirmedReceived; + LogPrint ("Session confirmed received"); + // TODO: + } + else + LogPrint ("Unexpected payload type ", (int)(header->flag >> 4)); + } + else + LogPrint ("MAC verifcation failed"); + } + void SSUSession::SendSessionRequest () { auto address = m_RemoteRouter ? m_RemoteRouter->GetSSUAddress () : nullptr; @@ -141,7 +168,7 @@ namespace ssu *(uint16_t *)(payload) = htobe16 (m_RemoteEndpoint.port ()); payload += 2; memcpy (signedData + 512, payload - 6, 6); // remote endpoint IP and port - *(uint32_t *)(signedData + 518) = m_Server->GetEndpoint ().address ().to_v4 ().to_ulong (); // our IP + *(uint32_t *)(signedData + 518) = htobe32 (m_Server->GetEndpoint ().address ().to_v4 ().to_ulong ()); // our IP *(uint16_t *)(signedData + 522) = htobe16 (m_Server->GetEndpoint ().port ()); // our port *(uint32_t *)(payload) = 0; // relay tag, always 0 for now payload += 4; @@ -164,6 +191,52 @@ namespace ssu m_Server->Send (buf, 368, m_RemoteEndpoint); } + void SSUSession::SendSessionConfirmed (const uint8_t * y, const uint8_t * ourAddress, uint32_t relayTag) + { + auto address = m_RemoteRouter ? m_RemoteRouter->GetSSUAddress () : nullptr; + if (!address) + { + LogPrint ("Missing remote SSU address"); + return; + } + + uint8_t buf[480 + 18]; + uint8_t * payload = buf + sizeof (SSUHeader); + *payload = 1; // 1 fragment + payload++; // info + size_t identLen = sizeof (i2p::context.GetRouterIdentity ()); // 387 bytes + *(uint16_t *)(payload) = htobe16 (identLen); + payload += 2; // cursize + memcpy (payload, (uint8_t *)&i2p::context.GetRouterIdentity (), identLen); + payload += identLen; + uint32_t signedOnTime = i2p::util::GetSecondsSinceEpoch (); + *(uint32_t *)(payload) = htobe32 (signedOnTime); // signed on time + payload += 4; + size_t paddingSize = ((payload - buf) + 40)%16; + if (paddingSize > 0) paddingSize = 16 - paddingSize; + // TODO: fill padding + payload += paddingSize; // padding size + + // signature + uint8_t signedData[532]; // x,y, our IP, our port, remote IP, remote port, relayTag, our signed on time + memcpy (signedData, i2p::context.GetRouterIdentity ().publicKey, 256); // x + memcpy (signedData + 256, y, 256); // y + memcpy (signedData + 512, ourAddress, 6); // our address/port as seem by party + *(uint32_t *)(signedData + 518) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ()); // remote IP + *(uint16_t *)(signedData + 522) = htobe16 (m_RemoteEndpoint.port ()); // remote port + *(uint32_t *)(signedData + 524) = htobe32 (relayTag); // relay tag + *(uint32_t *)(signedData + 528) = htobe32 (signedOnTime); // signed on time + i2p::context.Sign (signedData, 532, payload); // DSA signature + + uint8_t iv[16]; + CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator (); + rnd.GenerateBlock (iv, 16); // random iv + // encrypt message with session key + FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_CONFIRMED, buf, 480, m_SessionKey, iv, m_MacKey); + m_State = eSessionStateConfirmedSent; + m_Server->Send (buf, 480, m_RemoteEndpoint); + } + bool SSUSession::ProcessIntroKeyEncryptedMessage (uint8_t expectedPayloadType, i2p::data::RouterInfo& r, uint8_t * buf, size_t len) { auto address = r.GetSSUAddress (); diff --git a/SSU.h b/SSU.h index 2c797804..c33b3f83 100644 --- a/SSU.h +++ b/SSU.h @@ -30,12 +30,12 @@ namespace ssu const uint8_t PAYLOAD_TYPE_SESSION_REQUEST = 0; const uint8_t PAYLOAD_TYPE_SESSION_CREATED = 1; const uint8_t PAYLOAD_TYPE_SESSION_CONFIRMED = 2; - const uint8_t PAYLOAD_TYPE_SESSION_DESTROY = 8; const uint8_t PAYLOAD_TYPE_RELAY_REQUEST = 3; const uint8_t PAYLOAD_TYPE_RELAY_RESPONSE = 4; const uint8_t PAYLOAD_TYPE_RELAY_INTRO = 5; const uint8_t PAYLOAD_TYPE_DATA = 6; const uint8_t PAYLOAD_TYPE_TEST = 7; + const uint8_t PAYLOAD_TYPE_SESSION_DESTROY = 8; enum SessionState { @@ -69,6 +69,8 @@ namespace ssu void SendSessionRequest (); void ProcessSessionCreated (uint8_t * buf, size_t len); void SendSessionCreated (const uint8_t * x); + void ProcessSessionConfirmed (uint8_t * buf, size_t len); + void SendSessionConfirmed (const uint8_t * y, const uint8_t * ourAddress, uint32_t relayTag); bool ProcessIntroKeyEncryptedMessage (uint8_t expectedPayloadType, i2p::data::RouterInfo& r, uint8_t * buf, size_t len); void FillHeaderAndEncrypt (uint8_t payloadType, uint8_t * buf, size_t len, uint8_t * aesKey, uint8_t * iv, uint8_t * macKey);