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I2P: End-to-End encrypted and anonymous Internet
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421 lines
17 KiB
421 lines
17 KiB
/* |
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* Copyright (c) 2022-2024, 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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#ifndef SSU2_SESSION_H__ |
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#define SSU2_SESSION_H__ |
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#include <memory> |
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#include <functional> |
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#include <map> |
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#include <set> |
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#include <list> |
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#include <boost/asio.hpp> |
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#include "Crypto.h" |
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#include "RouterInfo.h" |
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#include "RouterContext.h" |
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#include "TransportSession.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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const int SSU2_CONNECT_TIMEOUT = 5; // 5 seconds |
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const int SSU2_TERMINATION_TIMEOUT = 165; // in seconds |
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const int SSU2_CLOCK_SKEW = 60; // in seconds |
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const int SSU2_CLOCK_THRESHOLD = 15; // in seconds, if more we should adjust |
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const int SSU2_TOKEN_EXPIRATION_TIMEOUT = 9; // for Retry message, in seconds |
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const int SSU2_NEXT_TOKEN_EXPIRATION_TIMEOUT = 52*60; // for next token block, in seconds |
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const int SSU2_TOKEN_EXPIRATION_THRESHOLD = 2; // in seconds |
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const int SSU2_RELAY_NONCE_EXPIRATION_TIMEOUT = 10; // in seconds |
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const int SSU2_PEER_TEST_EXPIRATION_TIMEOUT = 60; // 60 seconds |
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const size_t SSU2_MAX_PACKET_SIZE = 1500; |
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const size_t SSU2_MIN_PACKET_SIZE = 1280; |
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const int SSU2_HANDSHAKE_RESEND_INTERVAL = 1000; // in milliseconds |
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const int SSU2_MAX_NUM_RESENDS = 5; |
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const int SSU2_RESEND_ATTEMPT_MIN_INTERVAL = 3; // in milliseconds |
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const int SSU2_INCOMPLETE_MESSAGES_CLEANUP_TIMEOUT = 30; // in seconds |
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const int SSU2_MAX_NUM_RECEIVED_I2NP_MSGIDS = 5000; // how many msgID we store for duplicates check |
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const int SSU2_RECEIVED_I2NP_MSGIDS_CLEANUP_TIMEOUT = 10; // in seconds |
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const int SSU2_DECAY_INTERVAL = 20; // in seconds |
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const size_t SSU2_MIN_WINDOW_SIZE = 16; // in packets |
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const size_t SSU2_MAX_WINDOW_SIZE = 256; // in packets |
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const size_t SSU2_MIN_RTO = 100; // in milliseconds |
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const size_t SSU2_INITIAL_RTO = 540; // in milliseconds |
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const size_t SSU2_MAX_RTO = 2500; // in milliseconds |
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const double SSU2_UNKNOWN_RTT = -1; |
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const double SSU2_RTT_EWMA_ALPHA = 0.125; |
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const float SSU2_kAPPA = 1.8; |
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const int SSU2_MAX_NUM_ACNT = 255; // acnt, acks or nacks |
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const int SSU2_MAX_NUM_ACK_PACKETS = 511; // ackthrough + acnt + 1 range |
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const int SSU2_MAX_NUM_ACK_RANGES = 32; // to send |
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const uint8_t SSU2_MAX_NUM_FRAGMENTS = 64; |
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const int SSU2_SEND_DATETIME_NUM_PACKETS = 256; |
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// flags |
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const uint8_t SSU2_FLAG_IMMEDIATE_ACK_REQUESTED = 0x01; |
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enum SSU2MessageType |
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{ |
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eSSU2SessionRequest = 0, |
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eSSU2SessionCreated = 1, |
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eSSU2SessionConfirmed = 2, |
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eSSU2Data = 6, |
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eSSU2PeerTest = 7, |
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eSSU2Retry = 9, |
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eSSU2TokenRequest = 10, |
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eSSU2HolePunch = 11 |
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}; |
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enum SSU2BlockType |
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{ |
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eSSU2BlkDateTime = 0, |
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eSSU2BlkOptions, // 1 |
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eSSU2BlkRouterInfo, // 2 |
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eSSU2BlkI2NPMessage, // 3 |
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eSSU2BlkFirstFragment, // 4 |
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eSSU2BlkFollowOnFragment, // 5 |
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eSSU2BlkTermination, // 6 |
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eSSU2BlkRelayRequest, // 7 |
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eSSU2BlkRelayResponse, // 8 |
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eSSU2BlkRelayIntro, // 9 |
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eSSU2BlkPeerTest, // 10 |
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eSSU2BlkNextNonce, // 11 |
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eSSU2BlkAck, // 12 |
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eSSU2BlkAddress, // 13 |
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eSSU2BlkIntroKey, // 14 |
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eSSU2BlkRelayTagRequest, // 15 |
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eSSU2BlkRelayTag, // 16 |
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eSSU2BlkNewToken, // 17 |
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eSSU2BlkPathChallenge, // 18 |
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eSSU2BlkPathResponse, // 19 |
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eSSU2BlkFirstPacketNumber, // 20 |
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eSSU2BlkPadding = 254 |
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}; |
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enum SSU2SessionState |
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{ |
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eSSU2SessionStateUnknown, |
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eSSU2SessionStateTokenReceived, |
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eSSU2SessionStateSessionRequestSent, |
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eSSU2SessionStateSessionRequestReceived, |
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eSSU2SessionStateSessionCreatedSent, |
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eSSU2SessionStateSessionCreatedReceived, |
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eSSU2SessionStateSessionConfirmedSent, |
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eSSU2SessionStateEstablished, |
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eSSU2SessionStateClosing, |
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eSSU2SessionStateClosingConfirmed, |
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eSSU2SessionStateTerminated, |
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eSSU2SessionStateFailed, |
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eSSU2SessionStateIntroduced, |
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eSSU2SessionStatePeerTest, |
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eSSU2SessionStatePeerTestReceived, // 5 before 4 |
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eSSU2SessionStateVoidPeerTestReceived, // 5 before 4, but from connected recently |
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eSSU2SessionStateTokenRequestReceived |
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}; |
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enum SSU2PeerTestCode |
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{ |
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eSSU2PeerTestCodeAccept = 0, |
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eSSU2PeerTestCodeBobReasonUnspecified = 1, |
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eSSU2PeerTestCodeBobNoCharlieAvailable = 2, |
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eSSU2PeerTestCodeBobLimitExceeded = 3, |
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eSSU2PeerTestCodeBobSignatureFailure = 4, |
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eSSU2PeerTestCodeCharlieReasonUnspecified = 64, |
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eSSU2PeerTestCodeCharlieUnsupportedAddress = 65, |
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eSSU2PeerTestCodeCharlieLimitExceeded = 66, |
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eSSU2PeerTestCodeCharlieSignatureFailure = 67, |
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eSSU2PeerTestCodeCharlieAliceIsAlreadyConnected = 68, |
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eSSU2PeerTestCodeCharlieAliceIsBanned = 69, |
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eSSU2PeerTestCodeCharlieAliceIsUnknown = 70, |
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eSSU2PeerTestCodeUnspecified = 128 |
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}; |
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enum SSU2RelayResponseCode |
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{ |
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eSSU2RelayResponseCodeAccept = 0, |
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eSSU2RelayResponseCodeBobRelayTagNotFound = 5, |
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eSSU2RelayResponseCodeCharlieUnsupportedAddress = 65, |
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eSSU2RelayResponseCodeCharlieSignatureFailure = 67, |
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eSSU2RelayResponseCodeCharlieAliceIsUnknown = 70 |
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}; |
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enum SSU2TerminationReason |
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{ |
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eSSU2TerminationReasonNormalClose = 0, |
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eSSU2TerminationReasonTerminationReceived = 1, |
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eSSU2TerminationReasonIdleTimeout = 2, |
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eSSU2TerminationReasonRouterShutdown = 3, |
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eSSU2TerminationReasonDataPhaseAEADFailure= 4, |
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eSSU2TerminationReasonIncompatibleOptions = 5, |
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eSSU2TerminationReasonTncompatibleSignatureType = 6, |
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eSSU2TerminationReasonClockSkew = 7, |
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eSSU2TerminationPaddingViolation = 8, |
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eSSU2TerminationReasonAEADFramingError = 9, |
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eSSU2TerminationReasonPayloadFormatError = 10, |
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eSSU2TerminationReasonSessionRequestError = 11, |
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eSSU2TerminationReasonSessionCreatedError = 12, |
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eSSU2TerminationReasonSessionConfirmedError = 13, |
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eSSU2TerminationReasonTimeout = 14, |
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eSSU2TerminationReasonRouterInfoSignatureVerificationFail = 15, |
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eSSU2TerminationReasonInvalidS = 16, |
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eSSU2TerminationReasonBanned = 17, |
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eSSU2TerminationReasonBadToken = 18, |
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eSSU2TerminationReasonConnectionLimits = 19, |
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eSSU2TerminationReasonIncompatibleVersion = 20, |
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eSSU2TerminationReasonWrongNetID = 21, |
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eSSU2TerminationReasonReplacedByNewSession = 22 |
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}; |
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struct SSU2IncompleteMessage |
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{ |
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struct Fragment |
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{ |
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uint8_t buf[SSU2_MAX_PACKET_SIZE]; |
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size_t len; |
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int fragmentNum; |
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bool isLast; |
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std::shared_ptr<Fragment> next; |
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}; |
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std::shared_ptr<I2NPMessage> msg; |
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int nextFragmentNum; |
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uint32_t lastFragmentInsertTime; // in seconds |
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std::shared_ptr<Fragment> outOfSequenceFragments; // #1 and more |
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void AttachNextFragment (const uint8_t * fragment, size_t fragmentSize); |
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bool ConcatOutOfSequenceFragments (); // true if message complete |
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void AddOutOfSequenceFragment (std::shared_ptr<Fragment> fragment); |
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}; |
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struct SSU2SentPacket |
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{ |
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uint8_t payload[SSU2_MAX_PACKET_SIZE]; |
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size_t payloadSize = 0; |
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uint64_t sendTime; // in milliseconds |
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int numResends = 0; |
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}; |
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// RouterInfo flags |
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const uint8_t SSU2_ROUTER_INFO_FLAG_REQUEST_FLOOD = 0x01; |
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const uint8_t SSU2_ROUTER_INFO_FLAG_GZIP = 0x02; |
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class SSU2Server; |
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class SSU2Session: public TransportSession, public std::enable_shared_from_this<SSU2Session> |
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{ |
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protected: |
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union Header |
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{ |
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uint64_t ll[2]; |
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uint8_t buf[16]; |
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struct |
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{ |
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uint64_t connID; |
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uint32_t packetNum; |
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uint8_t type; |
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uint8_t flags[3]; |
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} h; |
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}; |
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private: |
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struct HandshakePacket |
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{ |
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Header header; |
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uint8_t headerX[48]; // part1 for SessionConfirmed |
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uint8_t payload[SSU2_MAX_PACKET_SIZE*2]; |
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size_t payloadSize = 0; |
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uint64_t sendTime = 0; // in milliseconds |
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bool isSecondFragment = false; // for SessionConfirmed |
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}; |
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typedef std::function<void ()> OnEstablished; |
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public: |
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SSU2Session (SSU2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter = nullptr, |
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std::shared_ptr<const i2p::data::RouterInfo::Address> addr = nullptr, bool noise = true); |
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virtual ~SSU2Session (); |
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void SetRemoteEndpoint (const boost::asio::ip::udp::endpoint& ep) { m_RemoteEndpoint = ep; }; |
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const boost::asio::ip::udp::endpoint& GetRemoteEndpoint () const { return m_RemoteEndpoint; }; |
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i2p::data::RouterInfo::CompatibleTransports GetRemoteTransports () const { return m_RemoteTransports; }; |
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i2p::data::RouterInfo::CompatibleTransports GetRemotePeerTestTransports () const { return m_RemotePeerTestTransports; }; |
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std::shared_ptr<const i2p::data::RouterInfo::Address> GetAddress () const { return m_Address; }; |
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void SetOnEstablished (OnEstablished e) { m_OnEstablished = e; }; |
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OnEstablished GetOnEstablished () const { return m_OnEstablished; }; |
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void Connect (); |
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bool Introduce (std::shared_ptr<SSU2Session> session, uint32_t relayTag); |
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void WaitForIntroduction (); |
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void SendPeerTest (); // Alice, Data message |
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void SendKeepAlive (); |
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void RequestTermination (SSU2TerminationReason reason); |
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void CleanUp (uint64_t ts); |
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void FlushData (); |
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void Done () override; |
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void SendLocalRouterInfo (bool update) override; |
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void SendI2NPMessages (const std::vector<std::shared_ptr<I2NPMessage> >& msgs) override; |
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void MoveSendQueue (std::shared_ptr<SSU2Session> other); |
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uint32_t GetRelayTag () const override { return m_RelayTag; }; |
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size_t Resend (uint64_t ts); // return number of resent packets |
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uint64_t GetLastResendTime () const { return m_LastResendTime; }; |
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bool IsEstablished () const override { return m_State == eSSU2SessionStateEstablished; }; |
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uint64_t GetConnID () const { return m_SourceConnID; }; |
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SSU2SessionState GetState () const { return m_State; }; |
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void SetState (SSU2SessionState state) { m_State = state; }; |
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bool ProcessFirstIncomingMessage (uint64_t connID, uint8_t * buf, size_t len); |
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bool ProcessSessionCreated (uint8_t * buf, size_t len); |
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bool ProcessSessionConfirmed (uint8_t * buf, size_t len); |
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bool ProcessRetry (uint8_t * buf, size_t len); |
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bool ProcessHolePunch (uint8_t * buf, size_t len); |
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virtual bool ProcessPeerTest (uint8_t * buf, size_t len); |
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void ProcessData (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& from); |
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protected: |
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SSU2Server& GetServer () { return m_Server; } |
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RouterStatus GetRouterStatus () const; |
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void SetRouterStatus (RouterStatus status) const; |
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uint64_t GetSourceConnID () const { return m_SourceConnID; } |
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void SetSourceConnID (uint64_t sourceConnID) { m_SourceConnID = sourceConnID; } |
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uint64_t GetDestConnID () const { return m_DestConnID; } |
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void SetDestConnID (uint64_t destConnID) { m_DestConnID = destConnID; } |
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void HandlePayload (const uint8_t * buf, size_t len); |
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void SendPeerTest (uint8_t msg, const uint8_t * signedData, size_t signedDataLen, const uint8_t * introKey); // PeerTest message |
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private: |
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void Terminate (); |
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void Established (); |
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void ScheduleConnectTimer (); |
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void HandleConnectTimer (const boost::system::error_code& ecode); |
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void PostI2NPMessages (std::vector<std::shared_ptr<I2NPMessage> > msgs); |
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bool SendQueue (); // returns true if ack block was sent |
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bool SendFragmentedMessage (std::shared_ptr<I2NPMessage> msg); |
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void ResendHandshakePacket (); |
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void ConnectAfterIntroduction (); |
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void ProcessSessionRequest (Header& header, uint8_t * buf, size_t len); |
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void ProcessTokenRequest (Header& header, uint8_t * buf, size_t len); |
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void SendSessionRequest (uint64_t token = 0); |
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void SendSessionCreated (const uint8_t * X); |
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void SendSessionConfirmed (const uint8_t * Y); |
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void KDFDataPhase (uint8_t * keydata_ab, uint8_t * keydata_ba); |
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void SendTokenRequest (); |
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void SendRetry (); |
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uint32_t SendData (const uint8_t * buf, size_t len, uint8_t flags = 0); // returns packet num |
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void SendQuickAck (); |
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void SendTermination (); |
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void SendHolePunch (uint32_t nonce, const boost::asio::ip::udp::endpoint& ep, const uint8_t * introKey, uint64_t token); |
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void SendPathResponse (const uint8_t * data, size_t len); |
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void SendPathChallenge (); |
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void HandleDateTime (const uint8_t * buf, size_t len); |
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void HandleRouterInfo (const uint8_t * buf, size_t len); |
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void HandleAck (const uint8_t * buf, size_t len); |
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void HandleAckRange (uint32_t firstPacketNum, uint32_t lastPacketNum, uint64_t ts); |
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void HandleAddress (const uint8_t * buf, size_t len); |
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bool ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep); |
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size_t CreateEndpoint (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& ep); |
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std::shared_ptr<const i2p::data::RouterInfo::Address> FindLocalAddress () const; |
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void AdjustMaxPayloadSize (); |
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bool GetTestingState () const; |
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void SetTestingState(bool testing) const; |
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std::shared_ptr<const i2p::data::RouterInfo> ExtractRouterInfo (const uint8_t * buf, size_t size); |
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bool UpdateReceivePacketNum (uint32_t packetNum); // for Ack, returns false if duplicate |
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void HandleFirstFragment (const uint8_t * buf, size_t len); |
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void HandleFollowOnFragment (const uint8_t * buf, size_t len); |
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void HandleRelayRequest (const uint8_t * buf, size_t len); |
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void HandleRelayIntro (const uint8_t * buf, size_t len, int attempts = 0); |
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void HandleRelayResponse (const uint8_t * buf, size_t len); |
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virtual void HandlePeerTest (const uint8_t * buf, size_t len); |
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void HandleI2NPMsg (std::shared_ptr<I2NPMessage>&& msg); |
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size_t CreateAddressBlock (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& ep); |
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size_t CreateRouterInfoBlock (uint8_t * buf, size_t len, std::shared_ptr<const i2p::data::RouterInfo> r); |
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size_t CreateRouterInfoBlock (uint8_t * buf, size_t len, std::shared_ptr<const i2p::data::RouterInfo::Buffer> riBuffer); |
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size_t CreateAckBlock (uint8_t * buf, size_t len); |
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size_t CreatePaddingBlock (uint8_t * buf, size_t len, size_t minSize = 0); |
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size_t CreateI2NPBlock (uint8_t * buf, size_t len, std::shared_ptr<I2NPMessage>&& msg); |
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size_t CreateFirstFragmentBlock (uint8_t * buf, size_t len, std::shared_ptr<I2NPMessage> msg); |
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size_t CreateFollowOnFragmentBlock (uint8_t * buf, size_t len, std::shared_ptr<I2NPMessage> msg, uint8_t& fragmentNum, uint32_t msgID); |
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size_t CreateRelayIntroBlock (uint8_t * buf, size_t len, const uint8_t * introData, size_t introDataLen); |
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size_t CreateRelayResponseBlock (uint8_t * buf, size_t len, SSU2RelayResponseCode code, uint32_t nonce, uint64_t token, bool v4); |
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size_t CreatePeerTestBlock (uint8_t * buf, size_t len, uint8_t msg, SSU2PeerTestCode code, const uint8_t * routerHash, const uint8_t * signedData, size_t signedDataLen); |
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size_t CreatePeerTestBlock (uint8_t * buf, size_t len, uint32_t nonce); // Alice |
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size_t CreateTerminationBlock (uint8_t * buf, size_t len); |
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private: |
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SSU2Server& m_Server; |
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std::shared_ptr<i2p::crypto::X25519Keys> m_EphemeralKeys; |
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std::unique_ptr<i2p::crypto::NoiseSymmetricState> m_NoiseState; |
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std::unique_ptr<HandshakePacket> m_SessionConfirmedFragment; // for Bob if applicable or second fragment for Alice |
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std::unique_ptr<HandshakePacket> m_SentHandshakePacket; // SessionRequest, SessionCreated or SessionConfirmed |
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std::shared_ptr<const i2p::data::RouterInfo::Address> m_Address; |
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boost::asio::ip::udp::endpoint m_RemoteEndpoint; |
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i2p::data::RouterInfo::CompatibleTransports m_RemoteTransports, m_RemotePeerTestTransports; |
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uint64_t m_DestConnID, m_SourceConnID; |
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SSU2SessionState m_State; |
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uint8_t m_KeyDataSend[64], m_KeyDataReceive[64]; |
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uint32_t m_SendPacketNum, m_ReceivePacketNum, m_LastDatetimeSentPacketNum; |
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std::set<uint32_t> m_OutOfSequencePackets; // packet nums > receive packet num |
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std::map<uint32_t, std::shared_ptr<SSU2SentPacket> > m_SentPackets; // packetNum -> packet |
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std::unordered_map<uint32_t, std::shared_ptr<SSU2IncompleteMessage> > m_IncompleteMessages; // msgID -> I2NP |
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std::unordered_map<uint32_t, std::pair <std::shared_ptr<SSU2Session>, uint64_t > > m_RelaySessions; // nonce->(Alice, timestamp) for Bob or nonce->(Charlie, timestamp) for Alice |
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std::unordered_map<uint32_t, std::pair <std::shared_ptr<SSU2Session>, uint64_t > > m_PeerTests; // same as for relay sessions |
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std::list<std::shared_ptr<I2NPMessage> > m_SendQueue; |
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i2p::I2NPMessagesHandler m_Handler; |
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bool m_IsDataReceived; |
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double m_RTT; |
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int m_MsgLocalExpirationTimeout; |
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int m_MsgLocalSemiExpirationTimeout; |
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size_t m_WindowSize, m_RTO; |
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uint32_t m_RelayTag; // between Bob and Charlie |
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OnEstablished m_OnEstablished; // callback from Established |
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boost::asio::deadline_timer m_ConnectTimer; |
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SSU2TerminationReason m_TerminationReason; |
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size_t m_MaxPayloadSize; |
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std::unique_ptr<i2p::data::IdentHash> m_PathChallenge; |
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std::unordered_map<uint32_t, uint32_t> m_ReceivedI2NPMsgIDs; // msgID -> timestamp in seconds |
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uint64_t m_LastResendTime, m_LastResendAttemptTime; // in milliseconds |
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}; |
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class SSU2PeerTestSession: public SSU2Session // for PeerTest msgs 5,6,7 |
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{ |
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public: |
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SSU2PeerTestSession (SSU2Server& server, uint64_t sourceConnID, uint64_t destConnID); |
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uint8_t GetMsgNumReceived () const { return m_MsgNumReceived; } |
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bool ProcessPeerTest (uint8_t * buf, size_t len) override; |
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private: |
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void HandlePeerTest (const uint8_t * buf, size_t len) override; |
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private: |
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uint8_t m_MsgNumReceived; |
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}; |
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inline uint64_t CreateHeaderMask (const uint8_t * kh, const uint8_t * nonce) |
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{ |
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uint64_t data = 0; |
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i2p::crypto::ChaCha20 ((uint8_t *)&data, 8, kh, nonce, (uint8_t *)&data); |
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return data; |
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} |
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} |
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} |
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#endif
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