mirror of
https://github.com/PurpleI2P/i2pd.git
synced 2024-10-31 09:20:38 +00:00
514 lines
16 KiB
C++
514 lines
16 KiB
C++
/*
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* Copyright (c) 2022, 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 <string.h>
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#include <openssl/rand.h>
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#include "Log.h"
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#include "RouterContext.h"
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#include "Transports.h"
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#include "Config.h"
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#include "SSU2.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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static 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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SSU2Session::SSU2Session (SSU2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter,
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std::shared_ptr<const i2p::data::RouterInfo::Address> addr, bool peerTest):
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TransportSession (in_RemoteRouter, SSU2_TERMINATION_TIMEOUT),
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m_Server (server), m_Address (addr), m_DestConnID (0), m_SourceConnID (0)
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{
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m_NoiseState.reset (new i2p::crypto::NoiseSymmetricState);
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if (in_RemoteRouter && m_Address)
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{
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// outgoing
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InitNoiseXKState1 (*m_NoiseState, m_Address->s);
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m_RemoteEndpoint = boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port);
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}
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else
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{
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// incoming
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InitNoiseXKState1 (*m_NoiseState, i2p::context.GetSSU2StaticPublicKey ());
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}
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}
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SSU2Session::~SSU2Session ()
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{
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}
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void SSU2Session::Connect ()
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{
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SendSessionRequest ();
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}
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void SSU2Session::SendSessionRequest ()
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{
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// we are Alice
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m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair ();
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Header header;
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uint8_t headerX[48], payload[40];
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// fill packet
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RAND_bytes ((uint8_t *)&m_DestConnID, 8);
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header.h.connID = m_DestConnID; // dest id
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memset (header.h.packetNum, 0, 4);
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header.h.type = eSSU2SessionRequest;
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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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RAND_bytes ((uint8_t *)&m_SourceConnID, 8);
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memcpy (headerX, &m_SourceConnID, 8); // source id
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RAND_bytes (headerX + 8, 8); // token
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memcpy (headerX + 16, m_EphemeralKeys->GetPublicKey (), 32); // X
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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::GetSecondsSinceEpoch ());
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size_t payloadSize = 7;
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uint8_t paddingSize = (rand () & 0x0F) + 1; // 1 - 16
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payload[payloadSize] = eSSU2BlkPadding;
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htobe16buf (payload + payloadSize + 1, paddingSize);
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payloadSize += paddingSize + 3;
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// KDF for session request
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m_NoiseState->MixHash ({ {header.buf, 16}, {headerX, 16} }); // h = SHA256(h || header)
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m_NoiseState->MixHash (m_EphemeralKeys->GetPublicKey (), 32); // h = SHA256(h || aepk);
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uint8_t sharedSecret[32];
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m_EphemeralKeys->Agree (m_Address->s, sharedSecret);
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m_NoiseState->MixKey (sharedSecret);
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// encrypt
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const uint8_t nonce[12] = {0};
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i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, payloadSize + 16, true);
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payloadSize += 16;
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header.ll[0] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 24));
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header.ll[1] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 12));
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i2p::crypto::ChaCha20 (headerX, 48, m_Address->i, nonce, headerX);
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m_NoiseState->MixHash (payload, 24); // h = SHA256(h || 24 byte encrypted payload from Session Request) for SessionCreated
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// send
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m_Server.AddPendingOutgoingSession (boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port), shared_from_this ());
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m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint);
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}
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void SSU2Session::ProcessSessionRequest (uint64_t connID, uint8_t * buf, size_t len)
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{
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// we are Bob
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m_SourceConnID = connID;
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Header header;
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header.h.connID = connID;
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memcpy (header.buf + 8, buf + 8, 8);
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header.ll[1] ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 12));
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if (header.h.type != eSSU2SessionRequest)
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{
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LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)header.h.type);
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return;
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}
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const uint8_t nonce[12] = {0};
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uint8_t headerX[48];
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i2p::crypto::ChaCha20 (buf + 16, 48, i2p::context.GetSSU2IntroKey (), nonce, headerX);
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memcpy (&m_DestConnID, headerX, 8);
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// KDF for session request
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m_NoiseState->MixHash ( { {header.buf, 16}, {headerX, 16} } ); // h = SHA256(h || header)
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m_NoiseState->MixHash (headerX + 16, 32); // h = SHA256(h || aepk);
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uint8_t sharedSecret[32];
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i2p::context.GetSSU2StaticKeys ().Agree (headerX + 16, sharedSecret);
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m_NoiseState->MixKey (sharedSecret);
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// decrypt
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uint8_t * payload = buf + 64;
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m_NoiseState->MixHash (payload, 24); // h = SHA256(h || 24 byte encrypted payload from Session Request) for SessionCreated
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if (!i2p::crypto::AEADChaCha20Poly1305 (payload, len - 80, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, len - 80, false))
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{
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LogPrint (eLogWarning, "SSU2: SessionRequest AEAD verification failed ");
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return;
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}
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// payload
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HandlePayload (payload, len - 80);
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m_Server.AddSession (m_SourceConnID, shared_from_this ());
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SendSessionCreated (headerX + 16);
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}
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void SSU2Session::SendSessionCreated (const uint8_t * X)
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{
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// we are Bob
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m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair ();
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// fill packet
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Header header;
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uint8_t headerX[48], payload[64];
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header.h.connID = m_DestConnID; // dest id
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memset (header.h.packetNum, 0, 4);
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header.h.type = eSSU2SessionCreated;
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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 (headerX, &m_SourceConnID, 8); // source id
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RAND_bytes (headerX + 8, 8); // token
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memcpy (headerX + 16, m_EphemeralKeys->GetPublicKey (), 32); // Y
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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::GetSecondsSinceEpoch ());
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size_t payloadSize = 7;
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payloadSize += CreateAddressBlock (m_RemoteEndpoint, payload, 57);
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uint8_t paddingSize = rand () & 0x0F; // 0 - 15
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if (paddingSize)
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{
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payload[payloadSize] = eSSU2BlkPadding;
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htobe16buf (payload + payloadSize + 1, paddingSize);
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payloadSize += paddingSize + 3;
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}
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// KDF for SessionCreated
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m_NoiseState->MixHash ( { {header.buf, 16}, {headerX, 16} } ); // h = SHA256(h || header)
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m_NoiseState->MixHash (headerX + 16, 32); // h = SHA256(h || bepk);
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uint8_t sharedSecret[32];
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m_EphemeralKeys->Agree (X, sharedSecret);
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m_NoiseState->MixKey (sharedSecret);
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// encrypt
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const uint8_t nonce[12] = {0};
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i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, payloadSize + 16, true);
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payloadSize += 16;
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header.ll[0] ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), payload + (payloadSize - 24));
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uint8_t kh2[32];
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i2p::crypto::HKDF (m_NoiseState->m_CK, nullptr, 0, "SessCreateHeader", kh2, 32); // k_header_2 = HKDF(chainKey, ZEROLEN, "SessCreateHeader", 32)
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header.ll[1] ^= CreateHeaderMask (kh2, payload + (payloadSize - 12));
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i2p::crypto::ChaCha20 (headerX, 48, kh2, nonce, headerX);
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// send
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m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint);
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}
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bool SSU2Session::ProcessSessionCreated (uint8_t * buf, size_t len)
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{
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// we are Alice
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Header header;
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header.h.connID = m_SourceConnID;
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memcpy (header.buf + 8, buf + 8, 8);
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uint8_t kh2[32];
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i2p::crypto::HKDF (m_NoiseState->m_CK, nullptr, 0, "SessCreateHeader", kh2, 32); // k_header_2 = HKDF(chainKey, ZEROLEN, "SessCreateHeader", 32)
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header.ll[1] ^= CreateHeaderMask (kh2, buf + (len - 12));
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if (header.h.type != eSSU2SessionCreated)
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{
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LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)header.h.type);
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return false;
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}
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const uint8_t nonce[12] = {0};
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uint8_t headerX[48];
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i2p::crypto::ChaCha20 (buf + 16, 48, kh2, nonce, headerX);
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// KDF for SessionCreated
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m_NoiseState->MixHash ( { {header.buf, 16}, {headerX, 16} } ); // h = SHA256(h || header)
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m_NoiseState->MixHash (headerX + 16, 32); // h = SHA256(h || bepk);
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uint8_t sharedSecret[32];
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m_EphemeralKeys->Agree (headerX + 16, sharedSecret);
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m_NoiseState->MixKey (sharedSecret);
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// decrypt
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uint8_t * payload = buf + 64;
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if (!i2p::crypto::AEADChaCha20Poly1305 (payload, len - 80, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, len - 80, false))
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{
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LogPrint (eLogWarning, "SSU2: SessionCreated AEAD verification failed ");
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return false;
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}
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// payload
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HandlePayload (payload, len - 80);
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m_Server.AddSession (m_SourceConnID, shared_from_this ());
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return true;
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}
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void SSU2Session::HandlePayload (const uint8_t * buf, size_t len)
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{
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size_t offset = 0;
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while (offset < len)
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{
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uint8_t blk = buf[offset];
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offset++;
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auto size = bufbe16toh (buf + offset);
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offset += 2;
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LogPrint (eLogDebug, "SSU2: Block type ", (int)blk, " of size ", size);
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if (size > len)
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{
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LogPrint (eLogError, "SSU2: Unexpected block length ", size);
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break;
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}
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switch (blk)
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{
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case eSSU2BlkDateTime:
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LogPrint (eLogDebug, "SSU2: Datetime");
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break;
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case eSSU2BlkOptions:
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LogPrint (eLogDebug, "SSU2: Options");
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break;
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case eSSU2BlkRouterInfo:
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break;
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case eSSU2BlkI2NPMessage:
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break;
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case eSSU2BlkFirstFragment:
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break;
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case eSSU2BlkFollowOnFragment:
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break;
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case eSSU2BlkTermination:
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break;
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case eSSU2BlkRelayRequest:
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break;
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case eSSU2BlkRelayResponse:
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break;
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case eSSU2BlkRelayIntro:
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break;
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case eSSU2BlkPeerTest:
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break;
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case eSSU2BlkNextNonce:
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break;
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case eSSU2BlkAck:
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break;
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case eSSU2BlkAddress:
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{
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boost::asio::ip::udp::endpoint ep;
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if (ExtractEndpoint (buf + offset, size, ep))
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LogPrint (eLogInfo, "SSU2: Our external address is ", ep);
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break;
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}
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case eSSU2BlkIntroKey:
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break;
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case eSSU2BlkRelayTagRequest:
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break;
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case eSSU2BlkRelayTag:
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break;
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case eSSU2BlkNewToken:
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break;
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case eSSU2BlkPathChallenge:
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break;
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case eSSU2BlkPathResponse:
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break;
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case eSSU2BlkFirstPacketNumber:
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break;
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case eSSU2BlkPadding:
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LogPrint (eLogDebug, "SSU2: Padding");
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break;
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default:
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LogPrint (eLogWarning, "SSU2: Unknown block type ", (int)blk);
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}
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offset += size;
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}
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}
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bool SSU2Session::ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep)
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{
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if (size < 2) return false;
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int port = bufbe16toh (buf);
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if (size == 6)
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{
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boost::asio::ip::address_v4::bytes_type bytes;
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memcpy (bytes.data (), buf + 2, 4);
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ep = boost::asio::ip::udp::endpoint (boost::asio::ip::address_v4 (bytes), port);
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}
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else if (size == 18)
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{
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boost::asio::ip::address_v6::bytes_type bytes;
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memcpy (bytes.data (), buf + 2, 16);
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ep = boost::asio::ip::udp::endpoint (boost::asio::ip::address_v6 (bytes), port);
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}
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else
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{
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LogPrint (eLogWarning, "SSU2: Address size ", int(size), " is not supported");
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return false;
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}
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return true;
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}
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size_t SSU2Session::CreateAddressBlock (const boost::asio::ip::udp::endpoint& ep, uint8_t * buf, size_t len)
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{
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if (len < 9) return 0;
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buf[0] = eSSU2BlkAddress;
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htobe16buf (buf + 3, ep.port ());
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size_t size = 0;
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if (ep.address ().is_v4 ())
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{
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memcpy (buf + 5, ep.address ().to_v4 ().to_bytes ().data (), 4);
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size = 6;
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}
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else if (ep.address ().is_v6 ())
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{
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if (len < 21) return 0;
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memcpy (buf + 5, ep.address ().to_v6 ().to_bytes ().data (), 16);
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size = 18;
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}
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else
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{
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LogPrint (eLogWarning, "SSU2: Wrong address type ", ep.address ().to_string ());
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return 0;
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}
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htobe16buf (buf + 1, size);
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return size + 3;
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}
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SSU2Server::SSU2Server ():
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RunnableServiceWithWork ("SSU2"), m_Socket (GetService ())
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{
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}
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void SSU2Server::Start ()
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{
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if (!IsRunning ())
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{
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StartIOService ();
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auto& addresses = i2p::context.GetRouterInfo ().GetAddresses ();
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for (const auto& address: addresses)
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{
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if (!address) continue;
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if (address->transportStyle == i2p::data::RouterInfo::eTransportSSU2)
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{
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auto port = address->port;
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if (!port)
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{
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uint16_t ssu2Port; i2p::config::GetOption ("ssu2.port", ssu2Port);
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if (ssu2Port) port = ssu2Port;
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else
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{
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uint16_t p; i2p::config::GetOption ("port", p);
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if (p) port = p;
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}
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}
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if (port)
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{
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OpenSocket (port);
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Receive ();
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}
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else
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LogPrint (eLogError, "SSU2: Can't start server because port not specified ");
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break;
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}
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}
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}
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}
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void SSU2Server::Stop ()
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{
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StopIOService ();
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}
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void SSU2Server::OpenSocket (int port)
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{
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try
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{
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m_Socket.open (boost::asio::ip::udp::v6());
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m_Socket.set_option (boost::asio::socket_base::receive_buffer_size (SSU2_SOCKET_RECEIVE_BUFFER_SIZE));
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m_Socket.set_option (boost::asio::socket_base::send_buffer_size (SSU2_SOCKET_SEND_BUFFER_SIZE));
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m_Socket.bind (boost::asio::ip::udp::endpoint (boost::asio::ip::udp::v6(), port));
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LogPrint (eLogInfo, "SSU2: Start listening port ", port);
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}
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catch (std::exception& ex )
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{
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LogPrint (eLogError, "SSU2: Failed to bind to port ", port, ": ", ex.what());
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ThrowFatal ("Unable to start SSU2 transport at port ", port, ": ", ex.what ());
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}
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}
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void SSU2Server::Receive ()
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{
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Packet * packet = m_PacketsPool.AcquireMt ();
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m_Socket.async_receive_from (boost::asio::buffer (packet->buf, SSU2_MTU), packet->from,
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std::bind (&SSU2Server::HandleReceivedFrom, this, std::placeholders::_1, std::placeholders::_2, packet));
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}
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void SSU2Server::HandleReceivedFrom (const boost::system::error_code& ecode, size_t bytes_transferred, Packet * packet)
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{
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if (!ecode)
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{
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packet->len = bytes_transferred;
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ProcessNextPacket (packet->buf, packet->len, packet->from);
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m_PacketsPool.ReleaseMt (packet);
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Receive ();
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}
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else
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{
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m_PacketsPool.ReleaseMt (packet);
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if (ecode != boost::asio::error::operation_aborted)
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{
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LogPrint (eLogError, "SSU2: Receive error: code ", ecode.value(), ": ", ecode.message ());
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auto port = m_Socket.local_endpoint ().port ();
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m_Socket.close ();
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OpenSocket (port);
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Receive ();
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}
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}
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}
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void SSU2Server::AddSession (uint64_t connID, std::shared_ptr<SSU2Session> session)
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{
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|
m_Sessions.emplace (connID, session);
|
|
}
|
|
|
|
void SSU2Server::AddPendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep, std::shared_ptr<SSU2Session> session)
|
|
{
|
|
m_PendingOutgoingSessions.emplace (ep, session);
|
|
}
|
|
|
|
void SSU2Server::ProcessNextPacket (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
|
|
{
|
|
uint64_t connID;
|
|
memcpy (&connID, buf, 8);
|
|
connID ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 24));
|
|
auto it = m_Sessions.find (connID);
|
|
if (it != m_Sessions.end ())
|
|
{
|
|
}
|
|
else
|
|
{
|
|
// check pending sessions if it's SessionCreated
|
|
auto it1 = m_PendingOutgoingSessions.find (senderEndpoint);
|
|
if (it1 != m_PendingOutgoingSessions.end ())
|
|
{
|
|
if (it1->second->ProcessSessionCreated (buf, len))
|
|
m_PendingOutgoingSessions.erase (it1);
|
|
}
|
|
else
|
|
{
|
|
// assume new incoming session
|
|
auto session = std::make_shared<SSU2Session> (*this);
|
|
session->SetRemoteEndpoint (senderEndpoint);
|
|
session->ProcessSessionRequest (connID, buf, len);
|
|
}
|
|
}
|
|
}
|
|
|
|
void SSU2Server::Send (const uint8_t * header, size_t headerLen, const uint8_t * headerX, size_t headerXLen,
|
|
const uint8_t * payload, size_t payloadLen, const boost::asio::ip::udp::endpoint& to)
|
|
{
|
|
std::vector<boost::asio::const_buffer> bufs
|
|
{
|
|
boost::asio::buffer (header, headerLen),
|
|
boost::asio::buffer (headerX, headerXLen),
|
|
boost::asio::buffer (payload, payloadLen)
|
|
};
|
|
boost::system::error_code ec;
|
|
m_Socket.send_to (bufs, to, 0, ec);
|
|
}
|
|
|
|
bool SSU2Server::CreateSession (std::shared_ptr<const i2p::data::RouterInfo> router,
|
|
std::shared_ptr<const i2p::data::RouterInfo::Address> address)
|
|
{
|
|
if (router && address)
|
|
GetService ().post (
|
|
[this, router, address]()
|
|
{
|
|
auto session = std::make_shared<SSU2Session> (*this, router, address);
|
|
session->Connect ();
|
|
});
|
|
else
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
}
|
|
}
|