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i2pd
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move transit tunnel build requests from I2NPProtocol.cpp to TransitTunnel.cpp

pull/2094/merge
orignal 2 weeks ago
parent
be24a3e336
commit
32921ead80
3 changed files with 279 additions and 270 deletions
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  1. 274
      libi2pd/I2NPProtocol.cpp
  2. 272
      libi2pd/TransitTunnel.cpp
  3. 3
      libi2pd/TransitTunnel.h

274
libi2pd/I2NPProtocol.cpp
Unescape View File

@ -10,20 +10,15 @@ @@ -10,20 +10,15 @@
#include <atomic>
#include "Base.h"
#include "Log.h"
#include "Crypto.h"
#include "I2PEndian.h"
#include "Timestamp.h"
#include "RouterContext.h"
#include "NetDb.hpp"
#include "Tunnel.h"
#include "Transports.h"
#include "Garlic.h"
#include "ECIESX25519AEADRatchetSession.h"
#include "TransitTunnel.h"
#include "I2NPProtocol.h"
#include "version.h"
using namespace i2p::transport;
namespace i2p
{
std::shared_ptr<I2NPMessage> NewI2NPMessage ()
@ -376,108 +371,8 @@ namespace i2p @@ -376,108 +371,8 @@ namespace i2p
return !msg->GetPayload ()[DATABASE_STORE_TYPE_OFFSET]; // 0- RouterInfo
}
static bool HandleBuildRequestRecords (int num, uint8_t * records, uint8_t * clearText)
{
for (int i = 0; i < num; i++)
{
uint8_t * record = records + i*TUNNEL_BUILD_RECORD_SIZE;
if (!memcmp (record + BUILD_REQUEST_RECORD_TO_PEER_OFFSET, (const uint8_t *)i2p::context.GetRouterInfo ().GetIdentHash (), 16))
{
LogPrint (eLogDebug, "I2NP: Build request record ", i, " is ours");
if (!i2p::context.DecryptTunnelBuildRecord (record + BUILD_REQUEST_RECORD_ENCRYPTED_OFFSET, clearText))
{
LogPrint (eLogWarning, "I2NP: Failed to decrypt tunnel build record");
return false;
}
if (!memcmp ((const uint8_t *)i2p::context.GetIdentHash (), clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32) && // if next ident is now ours
!(clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG)) // and not endpoint
{
LogPrint (eLogWarning, "I2NP: Next ident is ours in tunnel build record");
return false;
}
uint8_t retCode = 0;
// decide if we should accept tunnel
bool accept = i2p::context.AcceptsTunnels ();
if (accept)
{
auto congestionLevel = i2p::context.GetCongestionLevel (false);
if (congestionLevel >= CONGESTION_LEVEL_MEDIUM)
{
if (congestionLevel < CONGESTION_LEVEL_FULL)
{
// random reject depending on congestion level
int level = i2p::tunnel::tunnels.GetRng ()() % (CONGESTION_LEVEL_FULL - CONGESTION_LEVEL_MEDIUM) + CONGESTION_LEVEL_MEDIUM;
if (congestionLevel > level)
accept = false;
}
else
accept = false;
}
}
// replace record to reply
if (accept)
{
auto transitTunnel = i2p::tunnel::CreateTransitTunnel (
bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET),
clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
clearText + ECIES_BUILD_REQUEST_RECORD_LAYER_KEY_OFFSET,
clearText + ECIES_BUILD_REQUEST_RECORD_IV_KEY_OFFSET,
clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_GATEWAY_FLAG,
clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG);
if (!i2p::tunnel::tunnels.AddTransitTunnel (transitTunnel))
retCode = 30;
}
else
retCode = 30; // always reject with bandwidth reason (30)
memset (record + ECIES_BUILD_RESPONSE_RECORD_OPTIONS_OFFSET, 0, 2); // no options
record[ECIES_BUILD_RESPONSE_RECORD_RET_OFFSET] = retCode;
// encrypt reply
i2p::crypto::CBCEncryption encryption;
for (int j = 0; j < num; j++)
{
uint8_t * reply = records + j*TUNNEL_BUILD_RECORD_SIZE;
if (j == i)
{
uint8_t nonce[12];
memset (nonce, 0, 12);
auto& noiseState = i2p::context.GetCurrentNoiseState ();
if (!i2p::crypto::AEADChaCha20Poly1305 (reply, TUNNEL_BUILD_RECORD_SIZE - 16,
noiseState.m_H, 32, noiseState.m_CK, nonce, reply, TUNNEL_BUILD_RECORD_SIZE, true)) // encrypt
{
LogPrint (eLogWarning, "I2NP: Reply AEAD encryption failed");
return false;
}
}
else
{
encryption.SetKey (clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_KEY_OFFSET);
encryption.SetIV (clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_IV_OFFSET);
encryption.Encrypt(reply, TUNNEL_BUILD_RECORD_SIZE, reply);
}
}
return true;
}
}
return false;
}
static void HandleVariableTunnelBuildMsg (uint32_t replyMsgID, uint8_t * buf, size_t len)
{
int num = buf[0];
LogPrint (eLogDebug, "I2NP: VariableTunnelBuild ", num, " records");
if (num > i2p::tunnel::MAX_NUM_RECORDS)
{
LogPrint (eLogError, "I2NP: Too many records in VaribleTunnelBuild message ", num);
return;
}
if (len < num*TUNNEL_BUILD_RECORD_SIZE + 1)
{
LogPrint (eLogError, "I2NP: VaribleTunnelBuild message of ", num, " records is too short ", len);
return;
}
auto tunnel = i2p::tunnel::tunnels.GetPendingInboundTunnel (replyMsgID);
if (tunnel)
{
@ -496,24 +391,7 @@ namespace i2p @@ -496,24 +391,7 @@ namespace i2p
}
}
else
{
uint8_t clearText[ECIES_BUILD_REQUEST_RECORD_CLEAR_TEXT_SIZE];
if (HandleBuildRequestRecords (num, buf + 1, clearText))
{
if (clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG) // we are endpoint of outboud tunnel
{
// so we send it to reply tunnel
transports.SendMessage (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateTunnelGatewayMsg (bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
eI2NPVariableTunnelBuildReply, buf, len,
bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
}
else
transports.SendMessage (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateI2NPMessage (eI2NPVariableTunnelBuild, buf, len,
bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
}
}
i2p::tunnel::HandleVariableTransitTunnelBuildMsg (buf, len);
}
static void HandleTunnelBuildMsg (uint8_t * buf, size_t len)
@ -559,18 +437,6 @@ namespace i2p @@ -559,18 +437,6 @@ namespace i2p
static void HandleShortTunnelBuildMsg (uint32_t replyMsgID, uint8_t * buf, size_t len)
{
int num = buf[0];
LogPrint (eLogDebug, "I2NP: ShortTunnelBuild ", num, " records");
if (num > i2p::tunnel::MAX_NUM_RECORDS)
{
LogPrint (eLogError, "I2NP: Too many records in ShortTunnelBuild message ", num);
return;
}
if (len < num*SHORT_TUNNEL_BUILD_RECORD_SIZE + 1)
{
LogPrint (eLogError, "I2NP: ShortTunnelBuild message of ", num, " records is too short ", len);
return;
}
auto tunnel = i2p::tunnel::tunnels.GetPendingInboundTunnel (replyMsgID);
if (tunnel)
{
@ -589,140 +455,8 @@ namespace i2p @@ -589,140 +455,8 @@ namespace i2p
}
return;
}
const uint8_t * record = buf + 1;
for (int i = 0; i < num; i++)
{
if (!memcmp (record, (const uint8_t *)i2p::context.GetRouterInfo ().GetIdentHash (), 16))
{
LogPrint (eLogDebug, "I2NP: Short request record ", i, " is ours");
uint8_t clearText[SHORT_REQUEST_RECORD_CLEAR_TEXT_SIZE];
if (!i2p::context.DecryptTunnelShortRequestRecord (record + SHORT_REQUEST_RECORD_ENCRYPTED_OFFSET, clearText))
{
LogPrint (eLogWarning, "I2NP: Can't decrypt short request record ", i);
return;
}
if (clearText[SHORT_REQUEST_RECORD_LAYER_ENCRYPTION_TYPE]) // not AES
{
LogPrint (eLogWarning, "I2NP: Unknown layer encryption type ", clearText[SHORT_REQUEST_RECORD_LAYER_ENCRYPTION_TYPE], " in short request record");
return;
}
auto& noiseState = i2p::context.GetCurrentNoiseState ();
uint8_t replyKey[32]; // AEAD/Chacha20/Poly1305
i2p::crypto::AESKey layerKey, ivKey; // AES
i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "SMTunnelReplyKey", noiseState.m_CK);
memcpy (replyKey, noiseState.m_CK + 32, 32);
i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "SMTunnelLayerKey", noiseState.m_CK);
memcpy (layerKey, noiseState.m_CK + 32, 32);
bool isEndpoint = clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG;
if (isEndpoint)
{
i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "TunnelLayerIVKey", noiseState.m_CK);
memcpy (ivKey, noiseState.m_CK + 32, 32);
}
else
{
if (!memcmp ((const uint8_t *)i2p::context.GetIdentHash (), clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32)) // if next ident is now ours
{
LogPrint (eLogWarning, "I2NP: Next ident is ours in short request record");
return;
}
memcpy (ivKey, noiseState.m_CK , 32);
}
// check if we accept this tunnel
std::shared_ptr<i2p::tunnel::TransitTunnel> transitTunnel;
uint8_t retCode = 0;
if (!i2p::context.AcceptsTunnels () || i2p::context.GetCongestionLevel (false) >= CONGESTION_LEVEL_FULL)
retCode = 30;
if (!retCode)
{
// create new transit tunnel
transitTunnel = i2p::tunnel::CreateTransitTunnel (
bufbe32toh (clearText + SHORT_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET),
clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
bufbe32toh (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
layerKey, ivKey,
clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_GATEWAY_FLAG,
clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG);
if (!i2p::tunnel::tunnels.AddTransitTunnel (transitTunnel))
retCode = 30;
}
// encrypt reply
uint8_t nonce[12];
memset (nonce, 0, 12);
uint8_t * reply = buf + 1;
for (int j = 0; j < num; j++)
{
nonce[4] = j; // nonce is record #
if (j == i)
{
memset (reply + SHORT_RESPONSE_RECORD_OPTIONS_OFFSET, 0, 2); // no options
reply[SHORT_RESPONSE_RECORD_RET_OFFSET] = retCode;
if (!i2p::crypto::AEADChaCha20Poly1305 (reply, SHORT_TUNNEL_BUILD_RECORD_SIZE - 16,
noiseState.m_H, 32, replyKey, nonce, reply, SHORT_TUNNEL_BUILD_RECORD_SIZE, true)) // encrypt
{
LogPrint (eLogWarning, "I2NP: Short reply AEAD encryption failed");
return;
}
}
else
i2p::crypto::ChaCha20 (reply, SHORT_TUNNEL_BUILD_RECORD_SIZE, replyKey, nonce, reply);
reply += SHORT_TUNNEL_BUILD_RECORD_SIZE;
}
// send reply
auto onDrop = [transitTunnel]()
{
if (transitTunnel)
{
auto t = transitTunnel->GetCreationTime ();
if (t > i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT)
// make transit tunnel expired
transitTunnel->SetCreationTime (t - i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT);
}
};
if (isEndpoint)
{
auto replyMsg = NewI2NPShortMessage ();
replyMsg->Concat (buf, len);
replyMsg->FillI2NPMessageHeader (eI2NPShortTunnelBuildReply, bufbe32toh (clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET));
if (transitTunnel) replyMsg->onDrop = onDrop;
if (memcmp ((const uint8_t *)i2p::context.GetIdentHash (),
clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32)) // reply IBGW is not local?
{
i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "RGarlicKeyAndTag", noiseState.m_CK);
uint64_t tag;
memcpy (&tag, noiseState.m_CK, 8);
// we send it to reply tunnel
transports.SendMessage (clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateTunnelGatewayMsg (bufbe32toh (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
i2p::garlic::WrapECIESX25519Message (replyMsg, noiseState.m_CK + 32, tag)));
}
else
{
// IBGW is local
uint32_t tunnelID = bufbe32toh (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET);
auto tunnel = i2p::tunnel::tunnels.GetTunnel (tunnelID);
if (tunnel)
{
tunnel->SendTunnelDataMsg (replyMsg);
tunnel->FlushTunnelDataMsgs ();
}
else
LogPrint (eLogWarning, "I2NP: Tunnel ", tunnelID, " not found for short tunnel build reply");
}
}
else
{
auto msg = CreateI2NPMessage (eI2NPShortTunnelBuild, buf, len,
bufbe32toh (clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET));
if (transitTunnel) msg->onDrop = onDrop;
transports.SendMessage (clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, msg);
}
return;
}
record += SHORT_TUNNEL_BUILD_RECORD_SIZE;
}
else
i2p::tunnel::HandleShortTransitTunnelBuildMsg (buf, len);
}
std::shared_ptr<I2NPMessage> CreateTunnelDataMsg (const uint8_t * buf)

272
libi2pd/TransitTunnel.cpp
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@ -8,9 +8,12 @@ @@ -8,9 +8,12 @@
#include <string.h>
#include "I2PEndian.h"
#include "Crypto.h"
#include "Log.h"
#include "RouterContext.h"
#include "I2NPProtocol.h"
#include "Garlic.h"
#include "ECIESX25519AEADRatchetSession.h"
#include "Tunnel.h"
#include "Transports.h"
#include "TransitTunnel.h"
@ -118,5 +121,274 @@ namespace tunnel @@ -118,5 +121,274 @@ namespace tunnel
return std::make_shared<TransitTunnelParticipant> (receiveTunnelID, nextIdent, nextTunnelID, layerKey, ivKey);
}
}
void HandleShortTransitTunnelBuildMsg (uint8_t * buf, size_t len)
{
int num = buf[0];
LogPrint (eLogDebug, "TransitTunnel: ShortTunnelBuild ", num, " records");
if (num > i2p::tunnel::MAX_NUM_RECORDS)
{
LogPrint (eLogError, "TransitTunnel: Too many records in ShortTunnelBuild message ", num);
return;
}
if (len < num*SHORT_TUNNEL_BUILD_RECORD_SIZE + 1)
{
LogPrint (eLogError, "TransitTunnel: ShortTunnelBuild message of ", num, " records is too short ", len);
return;
}
const uint8_t * record = buf + 1;
for (int i = 0; i < num; i++)
{
if (!memcmp (record, (const uint8_t *)i2p::context.GetRouterInfo ().GetIdentHash (), 16))
{
LogPrint (eLogDebug, "TransitTunnel: Short request record ", i, " is ours");
uint8_t clearText[SHORT_REQUEST_RECORD_CLEAR_TEXT_SIZE];
if (!i2p::context.DecryptTunnelShortRequestRecord (record + SHORT_REQUEST_RECORD_ENCRYPTED_OFFSET, clearText))
{
LogPrint (eLogWarning, "TransitTunnel: Can't decrypt short request record ", i);
return;
}
if (clearText[SHORT_REQUEST_RECORD_LAYER_ENCRYPTION_TYPE]) // not AES
{
LogPrint (eLogWarning, "TransitTunnel: Unknown layer encryption type ", clearText[SHORT_REQUEST_RECORD_LAYER_ENCRYPTION_TYPE], " in short request record");
return;
}
auto& noiseState = i2p::context.GetCurrentNoiseState ();
uint8_t replyKey[32]; // AEAD/Chacha20/Poly1305
i2p::crypto::AESKey layerKey, ivKey; // AES
i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "SMTunnelReplyKey", noiseState.m_CK);
memcpy (replyKey, noiseState.m_CK + 32, 32);
i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "SMTunnelLayerKey", noiseState.m_CK);
memcpy (layerKey, noiseState.m_CK + 32, 32);
bool isEndpoint = clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG;
if (isEndpoint)
{
i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "TunnelLayerIVKey", noiseState.m_CK);
memcpy (ivKey, noiseState.m_CK + 32, 32);
}
else
{
if (!memcmp ((const uint8_t *)i2p::context.GetIdentHash (), clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32)) // if next ident is now ours
{
LogPrint (eLogWarning, "TransitTunnel: Next ident is ours in short request record");
return;
}
memcpy (ivKey, noiseState.m_CK , 32);
}
// check if we accept this tunnel
std::shared_ptr<i2p::tunnel::TransitTunnel> transitTunnel;
uint8_t retCode = 0;
if (!i2p::context.AcceptsTunnels () || i2p::context.GetCongestionLevel (false) >= CONGESTION_LEVEL_FULL)
retCode = 30;
if (!retCode)
{
// create new transit tunnel
transitTunnel = i2p::tunnel::CreateTransitTunnel (
bufbe32toh (clearText + SHORT_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET),
clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
bufbe32toh (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
layerKey, ivKey,
clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_GATEWAY_FLAG,
clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG);
if (!i2p::tunnel::tunnels.AddTransitTunnel (transitTunnel))
retCode = 30;
}
// encrypt reply
uint8_t nonce[12];
memset (nonce, 0, 12);
uint8_t * reply = buf + 1;
for (int j = 0; j < num; j++)
{
nonce[4] = j; // nonce is record #
if (j == i)
{
memset (reply + SHORT_RESPONSE_RECORD_OPTIONS_OFFSET, 0, 2); // no options
reply[SHORT_RESPONSE_RECORD_RET_OFFSET] = retCode;
if (!i2p::crypto::AEADChaCha20Poly1305 (reply, SHORT_TUNNEL_BUILD_RECORD_SIZE - 16,
noiseState.m_H, 32, replyKey, nonce, reply, SHORT_TUNNEL_BUILD_RECORD_SIZE, true)) // encrypt
{
LogPrint (eLogWarning, "TransitTunnel: Short reply AEAD encryption failed");
return;
}
}
else
i2p::crypto::ChaCha20 (reply, SHORT_TUNNEL_BUILD_RECORD_SIZE, replyKey, nonce, reply);
reply += SHORT_TUNNEL_BUILD_RECORD_SIZE;
}
// send reply
auto onDrop = [transitTunnel]()
{
if (transitTunnel)
{
auto t = transitTunnel->GetCreationTime ();
if (t > i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT)
// make transit tunnel expired
transitTunnel->SetCreationTime (t - i2p::tunnel::TUNNEL_EXPIRATION_TIMEOUT);
}
};
if (isEndpoint)
{
auto replyMsg = NewI2NPShortMessage ();
replyMsg->Concat (buf, len);
replyMsg->FillI2NPMessageHeader (eI2NPShortTunnelBuildReply, bufbe32toh (clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET));
if (transitTunnel) replyMsg->onDrop = onDrop;
if (memcmp ((const uint8_t *)i2p::context.GetIdentHash (),
clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32)) // reply IBGW is not local?
{
i2p::crypto::HKDF (noiseState.m_CK, nullptr, 0, "RGarlicKeyAndTag", noiseState.m_CK);
uint64_t tag;
memcpy (&tag, noiseState.m_CK, 8);
// we send it to reply tunnel
i2p::transport::transports.SendMessage (clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateTunnelGatewayMsg (bufbe32toh (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
i2p::garlic::WrapECIESX25519Message (replyMsg, noiseState.m_CK + 32, tag)));
}
else
{
// IBGW is local
uint32_t tunnelID = bufbe32toh (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET);
auto tunnel = i2p::tunnel::tunnels.GetTunnel (tunnelID);
if (tunnel)
{
tunnel->SendTunnelDataMsg (replyMsg);
tunnel->FlushTunnelDataMsgs ();
}
else
LogPrint (eLogWarning, "I2NP: Tunnel ", tunnelID, " not found for short tunnel build reply");
}
}
else
{
auto msg = CreateI2NPMessage (eI2NPShortTunnelBuild, buf, len,
bufbe32toh (clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET));
if (transitTunnel) msg->onDrop = onDrop;
i2p::transport::transports.SendMessage (clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, msg);
}
return;
}
record += SHORT_TUNNEL_BUILD_RECORD_SIZE;
}
}
static bool HandleBuildRequestRecords (int num, uint8_t * records, uint8_t * clearText)
{
for (int i = 0; i < num; i++)
{
uint8_t * record = records + i*TUNNEL_BUILD_RECORD_SIZE;
if (!memcmp (record + BUILD_REQUEST_RECORD_TO_PEER_OFFSET, (const uint8_t *)i2p::context.GetRouterInfo ().GetIdentHash (), 16))
{
LogPrint (eLogDebug, "TransitTunnel: Build request record ", i, " is ours");
if (!i2p::context.DecryptTunnelBuildRecord (record + BUILD_REQUEST_RECORD_ENCRYPTED_OFFSET, clearText))
{
LogPrint (eLogWarning, "TransitTunnel: Failed to decrypt tunnel build record");
return false;
}
if (!memcmp ((const uint8_t *)i2p::context.GetIdentHash (), clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32) && // if next ident is now ours
!(clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG)) // and not endpoint
{
LogPrint (eLogWarning, "TransitTunnel: Next ident is ours in tunnel build record");
return false;
}
uint8_t retCode = 0;
// decide if we should accept tunnel
bool accept = i2p::context.AcceptsTunnels ();
if (accept)
{
auto congestionLevel = i2p::context.GetCongestionLevel (false);
if (congestionLevel >= CONGESTION_LEVEL_MEDIUM)
{
if (congestionLevel < CONGESTION_LEVEL_FULL)
{
// random reject depending on congestion level
int level = i2p::tunnel::tunnels.GetRng ()() % (CONGESTION_LEVEL_FULL - CONGESTION_LEVEL_MEDIUM) + CONGESTION_LEVEL_MEDIUM;
if (congestionLevel > level)
accept = false;
}
else
accept = false;
}
}
// replace record to reply
if (accept)
{
auto transitTunnel = i2p::tunnel::CreateTransitTunnel (
bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET),
clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
clearText + ECIES_BUILD_REQUEST_RECORD_LAYER_KEY_OFFSET,
clearText + ECIES_BUILD_REQUEST_RECORD_IV_KEY_OFFSET,
clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_GATEWAY_FLAG,
clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG);
if (!i2p::tunnel::tunnels.AddTransitTunnel (transitTunnel))
retCode = 30;
}
else
retCode = 30; // always reject with bandwidth reason (30)
memset (record + ECIES_BUILD_RESPONSE_RECORD_OPTIONS_OFFSET, 0, 2); // no options
record[ECIES_BUILD_RESPONSE_RECORD_RET_OFFSET] = retCode;
// encrypt reply
i2p::crypto::CBCEncryption encryption;
for (int j = 0; j < num; j++)
{
uint8_t * reply = records + j*TUNNEL_BUILD_RECORD_SIZE;
if (j == i)
{
uint8_t nonce[12];
memset (nonce, 0, 12);
auto& noiseState = i2p::context.GetCurrentNoiseState ();
if (!i2p::crypto::AEADChaCha20Poly1305 (reply, TUNNEL_BUILD_RECORD_SIZE - 16,
noiseState.m_H, 32, noiseState.m_CK, nonce, reply, TUNNEL_BUILD_RECORD_SIZE, true)) // encrypt
{
LogPrint (eLogWarning, "TransitTunnel: Reply AEAD encryption failed");
return false;
}
}
else
{
encryption.SetKey (clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_KEY_OFFSET);
encryption.SetIV (clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_IV_OFFSET);
encryption.Encrypt(reply, TUNNEL_BUILD_RECORD_SIZE, reply);
}
}
return true;
}
}
return false;
}
void HandleVariableTransitTunnelBuildMsg (uint8_t * buf, size_t len)
{
int num = buf[0];
LogPrint (eLogDebug, "TransitTunnel: VariableTunnelBuild ", num, " records");
if (num > i2p::tunnel::MAX_NUM_RECORDS)
{
LogPrint (eLogError, "TransitTunnle: Too many records in VaribleTunnelBuild message ", num);
return;
}
if (len < num*TUNNEL_BUILD_RECORD_SIZE + 1)
{
LogPrint (eLogError, "TransitTunnel: VaribleTunnelBuild message of ", num, " records is too short ", len);
return;
}
uint8_t clearText[ECIES_BUILD_REQUEST_RECORD_CLEAR_TEXT_SIZE];
if (HandleBuildRequestRecords (num, buf + 1, clearText))
{
if (clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG) // we are endpoint of outboud tunnel
{
// so we send it to reply tunnel
i2p::transport::transports.SendMessage (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateTunnelGatewayMsg (bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
eI2NPVariableTunnelBuildReply, buf, len,
bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
}
else
i2p::transport::transports.SendMessage (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateI2NPMessage (eI2NPVariableTunnelBuild, buf, len,
bufbe32toh (clearText + ECIES_BUILD_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
}
}
}
}

3
libi2pd/TransitTunnel.h
Unescape View File

@ -108,6 +108,9 @@ namespace tunnel @@ -108,6 +108,9 @@ namespace tunnel
const i2p::data::IdentHash& nextIdent, uint32_t nextTunnelID,
const i2p::crypto::AESKey& layerKey, const i2p::crypto::AESKey& ivKey,
bool isGateway, bool isEndpoint);
void HandleShortTransitTunnelBuildMsg (uint8_t * buf, size_t len);
void HandleVariableTransitTunnelBuildMsg (uint8_t * buf, size_t len);
}
}

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