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193 lines
7.3 KiB
C++
193 lines
7.3 KiB
C++
/*
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* Copyright (c) 2013-2020, 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 ECIES_X25519_AEAD_RATCHET_SESSION_H__
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#define ECIES_X25519_AEAD_RATCHET_SESSION_H__
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#include <string.h>
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#include <inttypes.h>
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#include <functional>
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#include <memory>
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#include <vector>
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#include <list>
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#include <unordered_map>
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#include "Identity.h"
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#include "Crypto.h"
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#include "Garlic.h"
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#include "Tag.h"
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namespace i2p
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{
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namespace garlic
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{
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const int ECIESX25519_RESTART_TIMEOUT = 120; // number of second of inactivity we should restart after
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const int ECIESX25519_EXPIRATION_TIMEOUT = 480; // in seconds
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const int ECIESX25519_INCOMING_TAGS_EXPIRATION_TIMEOUT = 600; // in seconds
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const int ECIESX25519_PREVIOUS_TAGSET_EXPIRATION_TIMEOUT = 180; // 180
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const int ECIESX25519_TAGSET_MAX_NUM_TAGS = 4096; // number of tags we request new tagset after
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const int ECIESX25519_MIN_NUM_GENERATED_TAGS = 24;
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const int ECIESX25519_MAX_NUM_GENERATED_TAGS = 160;
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const int ECIESX25519_NSR_NUM_GENERATED_TAGS = 12;
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const size_t ECIESX25519_OPTIMAL_PAYLOAD_SIZE = 1912; // 1912 = 1956 /* to fit 2 tunnel messages */
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// - 16 /* I2NP header */ - 16 /* poly hash */ - 8 /* tag */ - 4 /* garlic length */
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class ECIESX25519AEADRatchetSession;
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class RatchetTagSet
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{
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public:
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RatchetTagSet (std::shared_ptr<ECIESX25519AEADRatchetSession> session): m_Session (session) {};
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void DHInitialize (const uint8_t * rootKey, const uint8_t * k);
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void NextSessionTagRatchet ();
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uint64_t GetNextSessionTag ();
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const uint8_t * GetNextRootKey () const { return m_NextRootKey; };
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int GetNextIndex () const { return m_NextIndex; };
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void GetSymmKey (int index, uint8_t * key);
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std::shared_ptr<ECIESX25519AEADRatchetSession> GetSession () { return m_Session.lock (); };
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int GetTagSetID () const { return m_TagSetID; };
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void SetTagSetID (int tagsetID) { m_TagSetID = tagsetID; };
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void Expire ();
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bool IsExpired (uint64_t ts) const { return m_ExpirationTimestamp && ts > m_ExpirationTimestamp; };
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private:
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union
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{
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uint64_t ll[8];
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uint8_t buf[64];
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const uint8_t * GetSessTagCK () const { return buf; }; // sessTag_chainKey = keydata[0:31]
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const uint8_t * GetSessTagConstant () const { return buf + 32; }; // SESSTAG_CONSTANT = keydata[32:63]
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uint64_t GetTag () const { return ll[4]; }; // tag = keydata[32:39]
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} m_KeyData;
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uint8_t m_SessTagConstant[32], m_SymmKeyCK[32], m_CurrentSymmKeyCK[64], m_NextRootKey[32];
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int m_NextIndex, m_NextSymmKeyIndex;
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std::unordered_map<int, i2p::data::Tag<32> > m_ItermediateSymmKeys;
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std::weak_ptr<ECIESX25519AEADRatchetSession> m_Session;
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int m_TagSetID = 0;
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uint64_t m_ExpirationTimestamp = 0;
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};
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enum ECIESx25519BlockType
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{
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eECIESx25519BlkDateTime = 0,
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eECIESx25519BlkSessionID = 1,
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eECIESx25519BlkTermination = 4,
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eECIESx25519BlkOptions = 5,
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eECIESx25519BlkNextKey = 7,
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eECIESx25519BlkAck = 8,
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eECIESx25519BlkAckRequest = 9,
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eECIESx25519BlkGalicClove = 11,
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eECIESx25519BlkPadding = 254
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};
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const uint8_t ECIESX25519_NEXT_KEY_KEY_PRESENT_FLAG = 0x01;
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const uint8_t ECIESX25519_NEXT_KEY_REVERSE_KEY_FLAG = 0x02;
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const uint8_t ECIESX25519_NEXT_KEY_REQUEST_REVERSE_KEY_FLAG = 0x04;
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class ECIESX25519AEADRatchetSession: public GarlicRoutingSession, public std::enable_shared_from_this<ECIESX25519AEADRatchetSession>
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{
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enum SessionState
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{
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eSessionStateNew = 0,
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eSessionStateNewSessionReceived,
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eSessionStateNewSessionSent,
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eSessionStateNewSessionReplySent,
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eSessionStateEstablished
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};
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struct DHRatchet
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{
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int keyID = 0;
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i2p::crypto::X25519Keys key;
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uint8_t remote[32]; // last remote public key
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bool newKey = true;
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};
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public:
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ECIESX25519AEADRatchetSession (GarlicDestination * owner, bool attachLeaseSet);
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~ECIESX25519AEADRatchetSession ();
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bool HandleNextMessage (uint8_t * buf, size_t len, std::shared_ptr<RatchetTagSet> receiveTagset, int index = 0);
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std::shared_ptr<I2NPMessage> WrapSingleMessage (std::shared_ptr<const I2NPMessage> msg);
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const uint8_t * GetRemoteStaticKey () const { return m_RemoteStaticKey; }
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void SetRemoteStaticKey (const uint8_t * key) { memcpy (m_RemoteStaticKey, key, 32); }
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void SetDestination (const i2p::data::IdentHash& dest) // TODO:
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{
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if (!m_Destination) m_Destination.reset (new i2p::data::IdentHash (dest));
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}
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bool CheckExpired (uint64_t ts); // true is expired
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bool CanBeRestarted (uint64_t ts) const { return ts > m_LastActivityTimestamp + ECIESX25519_RESTART_TIMEOUT; }
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bool IsRatchets () const { return true; };
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private:
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void ResetKeys ();
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void MixHash (const uint8_t * buf, size_t len);
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void CreateNonce (uint64_t seqn, uint8_t * nonce);
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bool GenerateEphemeralKeysAndEncode (uint8_t * buf); // buf is 32 bytes
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std::shared_ptr<RatchetTagSet> CreateNewSessionTagset ();
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bool HandleNewIncomingSession (const uint8_t * buf, size_t len);
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bool HandleNewOutgoingSessionReply (uint8_t * buf, size_t len);
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bool HandleExistingSessionMessage (uint8_t * buf, size_t len, std::shared_ptr<RatchetTagSet> receiveTagset, int index);
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void HandlePayload (const uint8_t * buf, size_t len, const std::shared_ptr<RatchetTagSet>& receiveTagset, int index);
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void HandleNextKey (const uint8_t * buf, size_t len, const std::shared_ptr<RatchetTagSet>& receiveTagset);
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bool NewOutgoingSessionMessage (const uint8_t * payload, size_t len, uint8_t * out, size_t outLen);
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bool NewSessionReplyMessage (const uint8_t * payload, size_t len, uint8_t * out, size_t outLen);
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bool NextNewSessionReplyMessage (const uint8_t * payload, size_t len, uint8_t * out, size_t outLen);
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bool NewExistingSessionMessage (const uint8_t * payload, size_t len, uint8_t * out, size_t outLen);
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std::vector<uint8_t> CreatePayload (std::shared_ptr<const I2NPMessage> msg, bool first);
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size_t CreateGarlicClove (std::shared_ptr<const I2NPMessage> msg, uint8_t * buf, size_t len, bool isDestination = false);
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size_t CreateLeaseSetClove (std::shared_ptr<const i2p::data::LocalLeaseSet> ls, uint64_t ts, uint8_t * buf, size_t len);
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void GenerateMoreReceiveTags (std::shared_ptr<RatchetTagSet> receiveTagset, int numTags);
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void NewNextSendRatchet ();
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private:
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uint8_t m_H[32], m_CK[64] /* [chainkey, key] */, m_RemoteStaticKey[32];
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uint8_t m_Aepk[32]; // Alice's ephemeral keys, for incoming only
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uint8_t m_NSREncodedKey[32], m_NSRH[32], m_NSRKey[32]; // new session reply, for incoming only
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i2p::crypto::X25519Keys m_EphemeralKeys;
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SessionState m_State = eSessionStateNew;
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uint64_t m_LastActivityTimestamp = 0; // incoming
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std::shared_ptr<RatchetTagSet> m_SendTagset, m_NSRTagset;
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std::unique_ptr<i2p::data::IdentHash> m_Destination;// TODO: might not need it
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std::list<std::pair<uint16_t, int> > m_AckRequests; // (tagsetid, index)
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bool m_SendReverseKey = false, m_SendForwardKey = false;
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std::unique_ptr<DHRatchet> m_NextReceiveRatchet, m_NextSendRatchet;
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public:
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// for HTTP only
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int GetState () const { return (int)m_State; }
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i2p::data::IdentHash GetDestination () const
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{
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return m_Destination ? *m_Destination : i2p::data::IdentHash ();
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}
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};
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std::shared_ptr<I2NPMessage> WrapECIESX25519AEADRatchetMessage (std::shared_ptr<const I2NPMessage> msg, const uint8_t * key, uint64_t tag);
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}
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}
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#endif
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