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I2P: End-to-End encrypted and anonymous Internet
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355 lines
13 KiB
355 lines
13 KiB
/* |
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* Copyright (c) 2024, The PurpleI2P Project |
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* |
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* This file is part of Purple i2pd project and licensed under BSD3 |
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* |
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* See full license text in LICENSE file at top of project tree |
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*/ |
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#include "Log.h" |
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#include "SSU2.h" |
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#include "SSU2OutOfSession.h" |
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namespace i2p |
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{ |
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namespace transport |
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{ |
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SSU2PeerTestSession::SSU2PeerTestSession (SSU2Server& server, uint64_t sourceConnID, uint64_t destConnID): |
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SSU2Session (server, nullptr, nullptr, false), |
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m_MsgNumReceived (0), m_NumResends (0),m_IsConnectedRecently (false), m_IsStatusChanged (false), |
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m_PeerTestResendTimer (server.GetService ()) |
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{ |
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if (!sourceConnID) sourceConnID = ~destConnID; |
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if (!destConnID) destConnID = ~sourceConnID; |
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SetSourceConnID (sourceConnID); |
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SetDestConnID (destConnID); |
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SetState (eSSU2SessionStatePeerTest); |
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SetTerminationTimeout (SSU2_PEER_TEST_EXPIRATION_TIMEOUT); |
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} |
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bool SSU2PeerTestSession::ProcessPeerTest (uint8_t * buf, size_t len) |
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{ |
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// we are Alice or Charlie, msgs 5,6,7 |
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Header header; |
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memcpy (header.buf, buf, 16); |
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header.ll[0] ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 24)); |
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header.ll[1] ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 12)); |
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if (header.h.type != eSSU2PeerTest) |
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{ |
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LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)header.h.type, " instead ", (int)eSSU2PeerTest); |
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return false; |
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} |
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if (len < 48) |
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{ |
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LogPrint (eLogWarning, "SSU2: PeerTest message too short ", len); |
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return false; |
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} |
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uint8_t nonce[12] = {0}; |
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uint64_t headerX[2]; // sourceConnID, token |
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i2p::crypto::ChaCha20 (buf + 16, 16, i2p::context.GetSSU2IntroKey (), nonce, (uint8_t *)headerX); |
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SetDestConnID (headerX[0]); |
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// decrypt and handle payload |
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uint8_t * payload = buf + 32; |
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CreateNonce (be32toh (header.h.packetNum), nonce); |
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uint8_t h[32]; |
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memcpy (h, header.buf, 16); |
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memcpy (h + 16, &headerX, 16); |
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if (!i2p::crypto::AEADChaCha20Poly1305 (payload, len - 48, h, 32, |
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i2p::context.GetSSU2IntroKey (), nonce, payload, len - 48, false)) |
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{ |
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LogPrint (eLogWarning, "SSU2: PeerTest AEAD verification failed "); |
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return false; |
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} |
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HandlePayload (payload, len - 48); |
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SetIsDataReceived (false); |
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return true; |
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} |
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void SSU2PeerTestSession::HandleAddress (const uint8_t * buf, size_t len) |
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{ |
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if (!ExtractEndpoint (buf, len, m_OurEndpoint)) |
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LogPrint (eLogWarning, "SSU2: Can't hanlde address block from peer test message"); |
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} |
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void SSU2PeerTestSession::HandlePeerTest (const uint8_t * buf, size_t len) |
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{ |
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// msgs 5-7 |
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if (len < 8) return; |
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uint8_t msg = buf[0]; |
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if (msg <= m_MsgNumReceived) |
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{ |
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LogPrint (eLogDebug, "SSU2: PeerTest msg num ", msg, " received after ", m_MsgNumReceived, ". Ignored"); |
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return; |
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} |
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size_t offset = 3; // points to signed data after msg + code + flag |
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uint32_t nonce = bufbe32toh (buf + offset + 1); // 1 - ver |
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switch (msg) // msg |
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{ |
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case 5: // Alice from Charlie 1 |
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{ |
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if (htobe64 (((uint64_t)nonce << 32) | nonce) == GetSourceConnID ()) |
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{ |
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m_PeerTestResendTimer.cancel (); // calcel delayed msg 6 if any |
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m_IsConnectedRecently = GetServer ().IsConnectedRecently (GetRemoteEndpoint ()); |
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if (GetAddress ()) |
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{ |
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if (!m_IsConnectedRecently) |
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SetRouterStatus (eRouterStatusOK); |
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else if (m_IsStatusChanged && GetRouterStatus () == eRouterStatusFirewalled) |
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SetRouterStatus (eRouterStatusUnknown); |
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SendPeerTest (6, buf + offset, len - offset); |
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} |
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} |
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else |
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LogPrint (eLogWarning, "SSU2: Peer test 5 nonce mismatch ", nonce, " connID=", GetSourceConnID ()); |
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break; |
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} |
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case 6: // Charlie from Alice |
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{ |
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m_PeerTestResendTimer.cancel (); // no more msg 5 resends |
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if (GetAddress ()) |
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SendPeerTest (7, buf + offset, len - offset); |
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else |
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LogPrint (eLogWarning, "SSU2: Unknown address for peer test 6"); |
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GetServer ().AddConnectedRecently (GetRemoteEndpoint (), i2p::util::GetSecondsSinceEpoch ()); |
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GetServer ().RequestRemoveSession (GetConnID ()); |
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break; |
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} |
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case 7: // Alice from Charlie 2 |
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{ |
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m_PeerTestResendTimer.cancel (); // no more msg 6 resends |
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if (m_MsgNumReceived < 5 && m_OurEndpoint.port ()) // msg 5 was not received |
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{ |
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if (m_OurEndpoint.address ().is_v4 ()) // ipv4 |
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{ |
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if (i2p::context.GetStatus () == eRouterStatusFirewalled) |
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{ |
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if (m_OurEndpoint.port () != GetServer ().GetPort (true)) |
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i2p::context.SetError (eRouterErrorSymmetricNAT); |
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else if (i2p::context.GetError () == eRouterErrorSymmetricNAT) |
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i2p::context.SetError (eRouterErrorNone); |
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} |
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} |
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else |
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{ |
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if (i2p::context.GetStatusV6 () == eRouterStatusFirewalled) |
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{ |
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if (m_OurEndpoint.port () != GetServer ().GetPort (false)) |
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i2p::context.SetErrorV6 (eRouterErrorSymmetricNAT); |
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else if (i2p::context.GetErrorV6 () == eRouterErrorSymmetricNAT) |
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i2p::context.SetErrorV6 (eRouterErrorNone); |
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} |
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} |
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} |
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GetServer ().AddConnectedRecently (GetRemoteEndpoint (), i2p::util::GetSecondsSinceEpoch ()); |
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GetServer ().RequestRemoveSession (GetConnID ()); |
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break; |
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} |
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default: |
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LogPrint (eLogWarning, "SSU2: PeerTest unexpected msg num ", msg); |
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return; |
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} |
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m_MsgNumReceived = msg; |
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} |
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void SSU2PeerTestSession::SendPeerTest (uint8_t msg) |
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{ |
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auto addr = GetAddress (); |
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if (!addr) return; |
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Header header; |
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uint8_t h[32], payload[SSU2_MAX_PACKET_SIZE]; |
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// fill packet |
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header.h.connID = GetDestConnID (); // dest id |
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RAND_bytes (header.buf + 8, 4); // random packet num |
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header.h.type = eSSU2PeerTest; |
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header.h.flags[0] = 2; // ver |
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header.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID |
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header.h.flags[2] = 0; // flag |
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memcpy (h, header.buf, 16); |
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htobuf64 (h + 16, GetSourceConnID ()); // source id |
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// payload |
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payload[0] = eSSU2BlkDateTime; |
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htobe16buf (payload + 1, 4); |
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htobe32buf (payload + 3, (i2p::util::GetMillisecondsSinceEpoch () + 500)/1000); |
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size_t payloadSize = 7; |
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if (msg == 6 || msg == 7) |
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payloadSize += CreateAddressBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize, GetRemoteEndpoint ()); |
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payloadSize += CreatePeerTestBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize, |
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msg, eSSU2PeerTestCodeAccept, nullptr, m_SignedData.data (), m_SignedData.size ()); |
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payloadSize += CreatePaddingBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize); |
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// encrypt |
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uint8_t n[12]; |
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CreateNonce (be32toh (header.h.packetNum), n); |
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i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, h, 32, addr->i, n, payload, payloadSize + 16, true); |
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payloadSize += 16; |
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header.ll[0] ^= CreateHeaderMask (addr->i, payload + (payloadSize - 24)); |
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header.ll[1] ^= CreateHeaderMask (addr->i, payload + (payloadSize - 12)); |
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memset (n, 0, 12); |
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i2p::crypto::ChaCha20 (h + 16, 16, addr->i, n, h + 16); |
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// send |
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GetServer ().Send (header.buf, 16, h + 16, 16, payload, payloadSize, GetRemoteEndpoint ()); |
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} |
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void SSU2PeerTestSession::SendPeerTest (uint8_t msg, const uint8_t * signedData, size_t signedDataLen, bool delayed) |
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{ |
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#if __cplusplus >= 202002L // C++20 |
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m_SignedData.assign (signedData, signedData + signedDataLen); |
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#else |
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m_SignedData.resize (signedDataLen); |
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memcpy (m_SignedData.data (), signedData, signedDataLen); |
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#endif |
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if (!delayed) |
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SendPeerTest (msg); |
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// schedule resend for msgs 5 or 6 |
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if (msg == 5 || msg == 6) |
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ScheduleResend (msg); |
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} |
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void SSU2PeerTestSession::SendPeerTest (uint8_t msg, const uint8_t * signedData, size_t signedDataLen, |
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std::shared_ptr<const i2p::data::RouterInfo::Address> addr, bool delayed) |
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{ |
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if (!addr) return; |
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SetAddress (addr); |
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SendPeerTest (msg, signedData, signedDataLen, delayed); |
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} |
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void SSU2PeerTestSession::Connect () |
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{ |
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LogPrint (eLogError, "SSU2: Can't connect peer test session"); |
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} |
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bool SSU2PeerTestSession::ProcessFirstIncomingMessage (uint64_t connID, uint8_t * buf, size_t len) |
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{ |
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LogPrint (eLogError, "SSU2: Can't handle incoming message in peer test session"); |
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return false; |
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} |
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void SSU2PeerTestSession::ScheduleResend (uint8_t msg) |
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{ |
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if (m_NumResends < SSU2_PEER_TEST_MAX_NUM_RESENDS) |
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{ |
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m_PeerTestResendTimer.expires_from_now (boost::posix_time::milliseconds( |
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SSU2_PEER_TEST_RESEND_INTERVAL + GetServer ().GetRng ()() % SSU2_PEER_TEST_RESEND_INTERVAL_VARIANCE)); |
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std::weak_ptr<SSU2PeerTestSession> s(std::static_pointer_cast<SSU2PeerTestSession>(shared_from_this ())); |
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m_PeerTestResendTimer.async_wait ([s, msg](const boost::system::error_code& ecode) |
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{ |
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if (ecode != boost::asio::error::operation_aborted) |
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{ |
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auto s1 = s.lock (); |
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if (s1) |
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{ |
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if (msg > s1->m_MsgNumReceived) |
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{ |
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s1->SendPeerTest (msg); |
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s1->m_NumResends++; |
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s1->ScheduleResend (msg); |
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} |
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} |
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} |
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}); |
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} |
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} |
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SSU2HolePunchSession::SSU2HolePunchSession (SSU2Server& server, uint32_t nonce, |
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const boost::asio::ip::udp::endpoint& remoteEndpoint, |
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std::shared_ptr<const i2p::data::RouterInfo::Address> addr): |
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SSU2Session (server), // we create full incoming session |
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m_NumResends (0), m_HolePunchResendTimer (server.GetService ()) |
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{ |
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// we are Charlie |
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uint64_t destConnID = htobe64 (((uint64_t)nonce << 32) | nonce); // dest id |
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uint32_t sourceConnID = ~destConnID; |
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SetSourceConnID (sourceConnID); |
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SetDestConnID (destConnID); |
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SetState (eSSU2SessionStateHolePunch); |
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SetRemoteEndpoint (remoteEndpoint); |
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SetAddress (addr); |
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SetTerminationTimeout (SSU2_RELAY_NONCE_EXPIRATION_TIMEOUT); |
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} |
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void SSU2HolePunchSession::SendHolePunch () |
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{ |
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auto addr = GetAddress (); |
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if (!addr) return; |
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auto& ep = GetRemoteEndpoint (); |
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LogPrint (eLogDebug, "SSU2: Sending HolePunch to ", ep); |
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Header header; |
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uint8_t h[32], payload[SSU2_MAX_PACKET_SIZE]; |
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// fill packet |
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header.h.connID = GetDestConnID (); // dest id |
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RAND_bytes (header.buf + 8, 4); // random packet num |
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header.h.type = eSSU2HolePunch; |
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header.h.flags[0] = 2; // ver |
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header.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID |
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header.h.flags[2] = 0; // flag |
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memcpy (h, header.buf, 16); |
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htobuf64 (h + 16, GetSourceConnID ()); // source id |
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RAND_bytes (h + 24, 8); // header token, to be ignored by Alice |
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// payload |
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payload[0] = eSSU2BlkDateTime; |
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htobe16buf (payload + 1, 4); |
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htobe32buf (payload + 3, (i2p::util::GetMillisecondsSinceEpoch () + 500)/1000); |
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size_t payloadSize = 7; |
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payloadSize += CreateAddressBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize, ep); |
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// relay response block |
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if (payloadSize + m_RelayResponseBlock.size () < GetMaxPayloadSize ()) |
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{ |
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memcpy (payload + payloadSize, m_RelayResponseBlock.data (), m_RelayResponseBlock.size ()); |
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payloadSize += m_RelayResponseBlock.size (); |
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} |
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payloadSize += CreatePaddingBlock (payload + payloadSize, GetMaxPayloadSize () - payloadSize); |
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// encrypt |
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uint8_t n[12]; |
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CreateNonce (be32toh (header.h.packetNum), n); |
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i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, h, 32, addr->i, n, payload, payloadSize + 16, true); |
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payloadSize += 16; |
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header.ll[0] ^= CreateHeaderMask (addr->i, payload + (payloadSize - 24)); |
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header.ll[1] ^= CreateHeaderMask (addr->i, payload + (payloadSize - 12)); |
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memset (n, 0, 12); |
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i2p::crypto::ChaCha20 (h + 16, 16, addr->i, n, h + 16); |
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// send |
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GetServer ().Send (header.buf, 16, h + 16, 16, payload, payloadSize, ep); |
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} |
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void SSU2HolePunchSession::SendHolePunch (const uint8_t * relayResponseBlock, size_t relayResponseBlockLen) |
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{ |
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#if __cplusplus >= 202002L // C++20 |
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m_RelayResponseBlock.assign (relayResponseBlock, relayResponseBlock + relayResponseBlockLen); |
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#else |
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m_RelayResponseBlock.resize (relayResponseBlockLen); |
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memcpy (m_RelayResponseBlock.data (), relayResponseBlock, relayResponseBlockLen); |
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#endif |
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SendHolePunch (); |
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ScheduleResend (); |
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} |
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void SSU2HolePunchSession::ScheduleResend () |
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{ |
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if (m_NumResends < SSU2_HOLE_PUNCH_MAX_NUM_RESENDS) |
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{ |
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m_HolePunchResendTimer.expires_from_now (boost::posix_time::milliseconds( |
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SSU2_HOLE_PUNCH_RESEND_INTERVAL + GetServer ().GetRng ()() % SSU2_HOLE_PUNCH_RESEND_INTERVAL_VARIANCE)); |
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std::weak_ptr<SSU2HolePunchSession> s(std::static_pointer_cast<SSU2HolePunchSession>(shared_from_this ())); |
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m_HolePunchResendTimer.async_wait ([s](const boost::system::error_code& ecode) |
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{ |
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if (ecode != boost::asio::error::operation_aborted) |
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{ |
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auto s1 = s.lock (); |
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if (s1 && s1->GetState () == eSSU2SessionStateHolePunch) |
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{ |
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s1->SendHolePunch (); |
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s1->m_NumResends++; |
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s1->ScheduleResend (); |
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} |
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} |
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}); |
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} |
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} |
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bool SSU2HolePunchSession::ProcessFirstIncomingMessage (uint64_t connID, uint8_t * buf, size_t len) |
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{ |
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m_HolePunchResendTimer.cancel (); |
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return SSU2Session::ProcessFirstIncomingMessage (connID, buf, len); |
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} |
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} |
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}
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