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i2pd/libi2pd/I2NPProtocol.cpp
orignal 0d3ede56cb reject duplicated trnsit tunnel
2023-01-05 11:59:47 -05:00

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/*
* Copyright (c) 2013-2023, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/
#include <string.h>
#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 "I2NPProtocol.h"
#include "version.h"
using namespace i2p::transport;
namespace i2p
{
std::shared_ptr<I2NPMessage> NewI2NPMessage ()
{
return std::make_shared<I2NPMessageBuffer<I2NP_MAX_MESSAGE_SIZE> >();
}
std::shared_ptr<I2NPMessage> NewI2NPShortMessage ()
{
return std::make_shared<I2NPMessageBuffer<I2NP_MAX_SHORT_MESSAGE_SIZE> >();
}
std::shared_ptr<I2NPMessage> NewI2NPTunnelMessage (bool endpoint)
{
return i2p::tunnel::tunnels.NewI2NPTunnelMessage (endpoint);
}
std::shared_ptr<I2NPMessage> NewI2NPMessage (size_t len)
{
return (len < I2NP_MAX_SHORT_MESSAGE_SIZE - I2NP_HEADER_SIZE - 2) ? NewI2NPShortMessage () : NewI2NPMessage ();
}
void I2NPMessage::FillI2NPMessageHeader (I2NPMessageType msgType, uint32_t replyMsgID, bool checksum)
{
SetTypeID (msgType);
if (!replyMsgID) RAND_bytes ((uint8_t *)&replyMsgID, 4);
SetMsgID (replyMsgID);
SetExpiration (i2p::util::GetMillisecondsSinceEpoch () + I2NP_MESSAGE_EXPIRATION_TIMEOUT);
UpdateSize ();
if (checksum) UpdateChks ();
}
void I2NPMessage::RenewI2NPMessageHeader ()
{
uint32_t msgID;
RAND_bytes ((uint8_t *)&msgID, 4);
SetMsgID (msgID);
SetExpiration (i2p::util::GetMillisecondsSinceEpoch () + I2NP_MESSAGE_EXPIRATION_TIMEOUT);
}
bool I2NPMessage::IsExpired () const
{
auto ts = i2p::util::GetMillisecondsSinceEpoch ();
auto exp = GetExpiration ();
return (ts > exp + I2NP_MESSAGE_CLOCK_SKEW) || (ts < exp - 3*I2NP_MESSAGE_CLOCK_SKEW); // check if expired or too far in future
}
std::shared_ptr<I2NPMessage> CreateI2NPMessage (I2NPMessageType msgType, const uint8_t * buf, size_t len, uint32_t replyMsgID)
{
auto msg = NewI2NPMessage (len);
if (msg->Concat (buf, len) < len)
LogPrint (eLogError, "I2NP: Message length ", len, " exceeds max length ", msg->maxLen);
msg->FillI2NPMessageHeader (msgType, replyMsgID);
return msg;
}
std::shared_ptr<I2NPMessage> CreateI2NPMessage (const uint8_t * buf, size_t len, std::shared_ptr<i2p::tunnel::InboundTunnel> from)
{
auto msg = NewI2NPMessage ();
if (msg->offset + len < msg->maxLen)
{
memcpy (msg->GetBuffer (), buf, len);
msg->len = msg->offset + len;
msg->from = from;
}
else
LogPrint (eLogError, "I2NP: Message length ", len, " exceeds max length");
return msg;
}
std::shared_ptr<I2NPMessage> CopyI2NPMessage (std::shared_ptr<I2NPMessage> msg)
{
if (!msg) return nullptr;
auto newMsg = NewI2NPMessage (msg->len);
newMsg->offset = msg->offset;
*newMsg = *msg;
return newMsg;
}
std::shared_ptr<I2NPMessage> CreateDeliveryStatusMsg (uint32_t msgID)
{
auto m = NewI2NPShortMessage ();
uint8_t * buf = m->GetPayload ();
if (msgID)
{
htobe32buf (buf + DELIVERY_STATUS_MSGID_OFFSET, msgID);
htobe64buf (buf + DELIVERY_STATUS_TIMESTAMP_OFFSET, i2p::util::GetMillisecondsSinceEpoch ());
}
else // for SSU establishment
{
RAND_bytes ((uint8_t *)&msgID, 4);
htobe32buf (buf + DELIVERY_STATUS_MSGID_OFFSET, msgID);
htobe64buf (buf + DELIVERY_STATUS_TIMESTAMP_OFFSET, i2p::context.GetNetID ());
}
m->len += DELIVERY_STATUS_SIZE;
m->FillI2NPMessageHeader (eI2NPDeliveryStatus);
return m;
}
std::shared_ptr<I2NPMessage> CreateRouterInfoDatabaseLookupMsg (const uint8_t * key, const uint8_t * from,
uint32_t replyTunnelID, bool exploratory, std::set<i2p::data::IdentHash> * excludedPeers)
{
auto m = excludedPeers ? NewI2NPMessage () : NewI2NPShortMessage ();
uint8_t * buf = m->GetPayload ();
memcpy (buf, key, 32); // key
buf += 32;
memcpy (buf, from, 32); // from
buf += 32;
uint8_t flag = exploratory ? DATABASE_LOOKUP_TYPE_EXPLORATORY_LOOKUP : DATABASE_LOOKUP_TYPE_ROUTERINFO_LOOKUP;
if (replyTunnelID)
{
*buf = flag | DATABASE_LOOKUP_DELIVERY_FLAG; // set delivery flag
htobe32buf (buf+1, replyTunnelID);
buf += 5;
}
else
{
*buf = flag; // flag
buf++;
}
if (excludedPeers)
{
int cnt = excludedPeers->size ();
htobe16buf (buf, cnt);
buf += 2;
for (auto& it: *excludedPeers)
{
memcpy (buf, it, 32);
buf += 32;
}
}
else
{
// nothing to exclude
htobuf16 (buf, 0);
buf += 2;
}
m->len += (buf - m->GetPayload ());
m->FillI2NPMessageHeader (eI2NPDatabaseLookup);
return m;
}
std::shared_ptr<I2NPMessage> CreateLeaseSetDatabaseLookupMsg (const i2p::data::IdentHash& dest,
const std::set<i2p::data::IdentHash>& excludedFloodfills,
std::shared_ptr<const i2p::tunnel::InboundTunnel> replyTunnel, const uint8_t * replyKey,
const uint8_t * replyTag, bool replyECIES)
{
int cnt = excludedFloodfills.size ();
auto m = cnt > 7 ? NewI2NPMessage () : NewI2NPShortMessage ();
uint8_t * buf = m->GetPayload ();
memcpy (buf, dest, 32); // key
buf += 32;
memcpy (buf, replyTunnel->GetNextIdentHash (), 32); // reply tunnel GW
buf += 32;
*buf = DATABASE_LOOKUP_DELIVERY_FLAG | DATABASE_LOOKUP_TYPE_LEASESET_LOOKUP; // flags
*buf |= (replyECIES ? DATABASE_LOOKUP_ECIES_FLAG : DATABASE_LOOKUP_ENCRYPTION_FLAG);
buf ++;
htobe32buf (buf, replyTunnel->GetNextTunnelID ()); // reply tunnel ID
buf += 4;
// excluded
if (cnt > 512)
{
LogPrint (eLogWarning, "I2NP: Too many peers to exclude ", cnt, " for DatabaseLookup");
cnt = 0;
}
htobe16buf (buf, cnt);
buf += 2;
if (cnt > 0)
{
for (auto& it: excludedFloodfills)
{
memcpy (buf, it, 32);
buf += 32;
}
}
// encryption
memcpy (buf, replyKey, 32);
buf[32] = 1; // 1 tag
if (replyECIES)
{
memcpy (buf + 33, replyTag, 8); // 8 bytes tag
buf += 41;
}
else
{
memcpy (buf + 33, replyTag, 32); // 32 bytes tag
buf += 65;
}
m->len += (buf - m->GetPayload ());
m->FillI2NPMessageHeader (eI2NPDatabaseLookup);
return m;
}
std::shared_ptr<I2NPMessage> CreateDatabaseSearchReply (const i2p::data::IdentHash& ident,
std::vector<i2p::data::IdentHash> routers)
{
auto m = NewI2NPShortMessage ();
uint8_t * buf = m->GetPayload ();
size_t len = 0;
memcpy (buf, ident, 32);
len += 32;
buf[len] = routers.size ();
len++;
for (const auto& it: routers)
{
memcpy (buf + len, it, 32);
len += 32;
}
memcpy (buf + len, i2p::context.GetRouterInfo ().GetIdentHash (), 32);
len += 32;
m->len += len;
m->FillI2NPMessageHeader (eI2NPDatabaseSearchReply);
return m;
}
std::shared_ptr<I2NPMessage> CreateDatabaseStoreMsg (std::shared_ptr<const i2p::data::RouterInfo> router,
uint32_t replyToken, std::shared_ptr<const i2p::tunnel::InboundTunnel> replyTunnel)
{
if (!router) // we send own RouterInfo
router = context.GetSharedRouterInfo ();
if (!router->GetBuffer ())
{
LogPrint (eLogError, "I2NP: Invalid RouterInfo buffer for DatabaseStore");
return nullptr;
}
auto m = NewI2NPShortMessage ();
uint8_t * payload = m->GetPayload ();
memcpy (payload + DATABASE_STORE_KEY_OFFSET, router->GetIdentHash (), 32);
payload[DATABASE_STORE_TYPE_OFFSET] = 0; // RouterInfo
htobe32buf (payload + DATABASE_STORE_REPLY_TOKEN_OFFSET, replyToken);
uint8_t * buf = payload + DATABASE_STORE_HEADER_SIZE;
if (replyToken)
{
if (replyTunnel)
{
htobe32buf (buf, replyTunnel->GetNextTunnelID ());
buf += 4; // reply tunnelID
memcpy (buf, replyTunnel->GetNextIdentHash (), 32);
buf += 32; // reply tunnel gateway
}
else
{
memset (buf, 0, 4); // zero tunnelID means direct reply
buf += 4;
memcpy (buf, context.GetIdentHash (), 32);
buf += 32;
}
}
uint8_t * sizePtr = buf;
buf += 2;
m->len += (buf - payload); // payload size
size_t size = 0;
if (router->GetBufferLen () + (buf - payload) <= 940) // fits one tunnel message
size = i2p::data::GzipNoCompression (router->GetBuffer (), router->GetBufferLen (), buf, m->maxLen -m->len);
else
{
i2p::data::GzipDeflator deflator;
size = deflator.Deflate (router->GetBuffer (), router->GetBufferLen (), buf, m->maxLen -m->len);
}
if (size)
{
htobe16buf (sizePtr, size); // size
m->len += size;
}
else
m = nullptr;
if (m)
m->FillI2NPMessageHeader (eI2NPDatabaseStore);
return m;
}
std::shared_ptr<I2NPMessage> CreateDatabaseStoreMsg (const i2p::data::IdentHash& storeHash, std::shared_ptr<const i2p::data::LeaseSet> leaseSet)
{
if (!leaseSet) return nullptr;
auto m = NewI2NPShortMessage ();
uint8_t * payload = m->GetPayload ();
memcpy (payload + DATABASE_STORE_KEY_OFFSET, storeHash, 32);
payload[DATABASE_STORE_TYPE_OFFSET] = leaseSet->GetStoreType (); // 1 for LeaseSet
htobe32buf (payload + DATABASE_STORE_REPLY_TOKEN_OFFSET, 0);
size_t size = DATABASE_STORE_HEADER_SIZE;
memcpy (payload + size, leaseSet->GetBuffer (), leaseSet->GetBufferLen ());
size += leaseSet->GetBufferLen ();
m->len += size;
m->FillI2NPMessageHeader (eI2NPDatabaseStore);
return m;
}
std::shared_ptr<I2NPMessage> CreateDatabaseStoreMsg (std::shared_ptr<const i2p::data::LocalLeaseSet> leaseSet, uint32_t replyToken, std::shared_ptr<const i2p::tunnel::InboundTunnel> replyTunnel)
{
if (!leaseSet) return nullptr;
auto m = NewI2NPShortMessage ();
uint8_t * payload = m->GetPayload ();
memcpy (payload + DATABASE_STORE_KEY_OFFSET, leaseSet->GetStoreHash (), 32);
payload[DATABASE_STORE_TYPE_OFFSET] = leaseSet->GetStoreType (); // LeaseSet or LeaseSet2
htobe32buf (payload + DATABASE_STORE_REPLY_TOKEN_OFFSET, replyToken);
size_t size = DATABASE_STORE_HEADER_SIZE;
if (replyToken && replyTunnel)
{
if (replyTunnel)
{
htobe32buf (payload + size, replyTunnel->GetNextTunnelID ());
size += 4; // reply tunnelID
memcpy (payload + size, replyTunnel->GetNextIdentHash (), 32);
size += 32; // reply tunnel gateway
}
else
htobe32buf (payload + DATABASE_STORE_REPLY_TOKEN_OFFSET, 0);
}
memcpy (payload + size, leaseSet->GetBuffer (), leaseSet->GetBufferLen ());
size += leaseSet->GetBufferLen ();
m->len += size;
m->FillI2NPMessageHeader (eI2NPDatabaseStore);
return m;
}
bool IsRouterInfoMsg (std::shared_ptr<I2NPMessage> msg)
{
if (!msg || msg->GetTypeID () != eI2NPDatabaseStore) return false;
return !msg->GetPayload ()[DATABASE_STORE_TYPE_OFFSET]; // 0- RouterInfo
}
static uint16_t g_MaxNumTransitTunnels = DEFAULT_MAX_NUM_TRANSIT_TUNNELS; // TODO:
void SetMaxNumTransitTunnels (uint16_t maxNumTransitTunnels)
{
if (maxNumTransitTunnels > 0 && g_MaxNumTransitTunnels != maxNumTransitTunnels)
{
LogPrint (eLogDebug, "I2NP: Max number of transit tunnels set to ", maxNumTransitTunnels);
g_MaxNumTransitTunnels = maxNumTransitTunnels;
}
}
uint16_t GetMaxNumTransitTunnels ()
{
return g_MaxNumTransitTunnels;
}
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)) return false;
uint8_t retCode = 0;
// replace record to reply
if (i2p::context.AcceptsTunnels () &&
i2p::tunnel::tunnels.GetTransitTunnels ().size () <= g_MaxNumTransitTunnels &&
!i2p::transport::transports.IsBandwidthExceeded () &&
!i2p::transport::transports.IsTransitBandwidthExceeded ())
{
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 (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)
{
// endpoint of inbound tunnel
LogPrint (eLogDebug, "I2NP: VariableTunnelBuild reply for tunnel ", tunnel->GetTunnelID ());
if (tunnel->HandleTunnelBuildResponse (buf, len))
{
LogPrint (eLogInfo, "I2NP: Inbound tunnel ", tunnel->GetTunnelID (), " has been created");
tunnel->SetState (i2p::tunnel::eTunnelStateEstablished);
i2p::tunnel::tunnels.AddInboundTunnel (tunnel);
}
else
{
LogPrint (eLogInfo, "I2NP: Inbound tunnel ", tunnel->GetTunnelID (), " has been declined");
tunnel->SetState (i2p::tunnel::eTunnelStateBuildFailed);
}
}
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)));
}
}
}
static void HandleTunnelBuildMsg (uint8_t * buf, size_t len)
{
LogPrint (eLogWarning, "I2NP: TunnelBuild is too old for ECIES router");
}
static void HandleTunnelBuildReplyMsg (uint32_t replyMsgID, uint8_t * buf, size_t len, bool isShort)
{
int num = buf[0];
LogPrint (eLogDebug, "I2NP: TunnelBuildReplyMsg of ", num, " records replyMsgID=", replyMsgID);
size_t recordSize = isShort ? SHORT_TUNNEL_BUILD_RECORD_SIZE : TUNNEL_BUILD_RECORD_SIZE;
if (len < num*recordSize + 1)
{
LogPrint (eLogError, "I2NP: TunnelBuildReply message of ", num, " records is too short ", len);
return;
}
auto tunnel = i2p::tunnel::tunnels.GetPendingOutboundTunnel (replyMsgID);
if (tunnel)
{
// reply for outbound tunnel
if (tunnel->HandleTunnelBuildResponse (buf, len))
{
LogPrint (eLogInfo, "I2NP: Outbound tunnel ", tunnel->GetTunnelID (), " has been created");
tunnel->SetState (i2p::tunnel::eTunnelStateEstablished);
i2p::tunnel::tunnels.AddOutboundTunnel (tunnel);
}
else
{
LogPrint (eLogInfo, "I2NP: Outbound tunnel ", tunnel->GetTunnelID (), " has been declined");
tunnel->SetState (i2p::tunnel::eTunnelStateBuildFailed);
}
}
else
LogPrint (eLogWarning, "I2NP: Pending tunnel for message ", replyMsgID, " not found");
}
static void HandleShortTunnelBuildMsg (uint32_t replyMsgID, uint8_t * buf, size_t len)
{
int num = buf[0];
LogPrint (eLogDebug, "I2NP: ShortTunnelBuild ", num, " records");
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)
{
// endpoint of inbound tunnel
LogPrint (eLogDebug, "I2NP: ShortTunnelBuild reply for tunnel ", tunnel->GetTunnelID ());
if (tunnel->HandleTunnelBuildResponse (buf, len))
{
LogPrint (eLogInfo, "I2NP: Inbound tunnel ", tunnel->GetTunnelID (), " has been created");
tunnel->SetState (i2p::tunnel::eTunnelStateEstablished);
i2p::tunnel::tunnels.AddInboundTunnel (tunnel);
}
else
{
LogPrint (eLogInfo, "I2NP: Inbound tunnel ", tunnel->GetTunnelID (), " has been declined");
tunnel->SetState (i2p::tunnel::eTunnelStateBuildFailed);
}
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
memcpy (ivKey, noiseState.m_CK , 32);
// check if we accept this tunnel
uint8_t retCode = 0;
if (!i2p::context.AcceptsTunnels () ||
i2p::tunnel::tunnels.GetTransitTunnels ().size () > g_MaxNumTransitTunnels ||
i2p::transport::transports.IsBandwidthExceeded () ||
i2p::transport::transports.IsTransitBandwidthExceeded ())
retCode = 30;
if (!retCode)
{
// create new transit tunnel
auto 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
if (isEndpoint)
{
auto replyMsg = NewI2NPShortMessage ();
replyMsg->Concat (buf, len);
replyMsg->FillI2NPMessageHeader (eI2NPShortTunnelBuildReply, bufbe32toh (clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET));
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);
else
LogPrint (eLogWarning, "I2NP: Tunnel ", tunnelID, " not found for short tunnel build reply");
}
}
else
transports.SendMessage (clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateI2NPMessage (eI2NPShortTunnelBuild, buf, len,
bufbe32toh (clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
return;
}
record += SHORT_TUNNEL_BUILD_RECORD_SIZE;
}
}
std::shared_ptr<I2NPMessage> CreateTunnelDataMsg (const uint8_t * buf)
{
auto msg = NewI2NPTunnelMessage (false);
msg->Concat (buf, i2p::tunnel::TUNNEL_DATA_MSG_SIZE);
msg->FillI2NPMessageHeader (eI2NPTunnelData);
return msg;
}
std::shared_ptr<I2NPMessage> CreateTunnelDataMsg (uint32_t tunnelID, const uint8_t * payload)
{
auto msg = NewI2NPTunnelMessage (false);
htobe32buf (msg->GetPayload (), tunnelID);
msg->len += 4; // tunnelID
msg->Concat (payload, i2p::tunnel::TUNNEL_DATA_MSG_SIZE - 4);
msg->FillI2NPMessageHeader (eI2NPTunnelData);
return msg;
}
std::shared_ptr<I2NPMessage> CreateEmptyTunnelDataMsg (bool endpoint)
{
auto msg = NewI2NPTunnelMessage (endpoint);
msg->len += i2p::tunnel::TUNNEL_DATA_MSG_SIZE;
return msg;
}
std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg (uint32_t tunnelID, const uint8_t * buf, size_t len)
{
auto msg = NewI2NPMessage (len);
uint8_t * payload = msg->GetPayload ();
htobe32buf (payload + TUNNEL_GATEWAY_HEADER_TUNNELID_OFFSET, tunnelID);
htobe16buf (payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET, len);
msg->len += TUNNEL_GATEWAY_HEADER_SIZE;
if (msg->Concat (buf, len) < len)
LogPrint (eLogError, "I2NP: Tunnel gateway buffer overflow ", msg->maxLen);
msg->FillI2NPMessageHeader (eI2NPTunnelGateway);
return msg;
}
std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg (uint32_t tunnelID, std::shared_ptr<I2NPMessage> msg)
{
if (msg->offset >= I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE)
{
// message is capable to be used without copying
uint8_t * payload = msg->GetBuffer () - TUNNEL_GATEWAY_HEADER_SIZE;
htobe32buf (payload + TUNNEL_GATEWAY_HEADER_TUNNELID_OFFSET, tunnelID);
int len = msg->GetLength ();
htobe16buf (payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET, len);
msg->offset -= (I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE);
msg->len = msg->offset + I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE +len;
msg->FillI2NPMessageHeader (eI2NPTunnelGateway);
return msg;
}
else
return CreateTunnelGatewayMsg (tunnelID, msg->GetBuffer (), msg->GetLength ());
}
std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg (uint32_t tunnelID, I2NPMessageType msgType,
const uint8_t * buf, size_t len, uint32_t replyMsgID)
{
auto msg = NewI2NPMessage (len);
size_t gatewayMsgOffset = I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE;
msg->offset += gatewayMsgOffset;
msg->len += gatewayMsgOffset;
if (msg->Concat (buf, len) < len)
LogPrint (eLogError, "I2NP: Tunnel gateway buffer overflow ", msg->maxLen);
msg->FillI2NPMessageHeader (msgType, replyMsgID); // create content message
len = msg->GetLength ();
msg->offset -= gatewayMsgOffset;
uint8_t * payload = msg->GetPayload ();
htobe32buf (payload + TUNNEL_GATEWAY_HEADER_TUNNELID_OFFSET, tunnelID);
htobe16buf (payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET, len);
msg->FillI2NPMessageHeader (eI2NPTunnelGateway); // gateway message
return msg;
}
size_t GetI2NPMessageLength (const uint8_t * msg, size_t len)
{
if (len < I2NP_HEADER_SIZE_OFFSET + 2)
{
LogPrint (eLogError, "I2NP: Message length ", len, " is smaller than header");
return len;
}
auto l = bufbe16toh (msg + I2NP_HEADER_SIZE_OFFSET) + I2NP_HEADER_SIZE;
if (l > len)
{
LogPrint (eLogError, "I2NP: Message length ", l, " exceeds buffer length ", len);
l = len;
}
return l;
}
void HandleI2NPMessage (uint8_t * msg, size_t len)
{
if (len < I2NP_HEADER_SIZE)
{
LogPrint (eLogError, "I2NP: Message length ", len, " is smaller than header");
return;
}
uint8_t typeID = msg[I2NP_HEADER_TYPEID_OFFSET];
uint32_t msgID = bufbe32toh (msg + I2NP_HEADER_MSGID_OFFSET);
LogPrint (eLogDebug, "I2NP: Msg received len=", len,", type=", (int)typeID, ", msgID=", (unsigned int)msgID);
uint8_t * buf = msg + I2NP_HEADER_SIZE;
auto size = bufbe16toh (msg + I2NP_HEADER_SIZE_OFFSET);
len -= I2NP_HEADER_SIZE;
if (size > len)
{
LogPrint (eLogError, "I2NP: Payload size ", size, " exceeds buffer length ", len);
size = len;
}
switch (typeID)
{
case eI2NPVariableTunnelBuild:
HandleVariableTunnelBuildMsg (msgID, buf, size);
break;
case eI2NPShortTunnelBuild:
HandleShortTunnelBuildMsg (msgID, buf, size);
break;
case eI2NPVariableTunnelBuildReply:
HandleTunnelBuildReplyMsg (msgID, buf, size, false);
break;
case eI2NPShortTunnelBuildReply:
HandleTunnelBuildReplyMsg (msgID, buf, size, true);
break;
case eI2NPTunnelBuild:
HandleTunnelBuildMsg (buf, size);
break;
case eI2NPTunnelBuildReply:
// TODO:
break;
default:
LogPrint (eLogWarning, "I2NP: Unexpected message ", (int)typeID);
}
}
void HandleI2NPMessage (std::shared_ptr<I2NPMessage> msg)
{
if (msg)
{
uint8_t typeID = msg->GetTypeID ();
LogPrint (eLogDebug, "I2NP: Handling message with type ", (int)typeID);
switch (typeID)
{
case eI2NPTunnelData:
i2p::tunnel::tunnels.PostTunnelData (msg);
break;
case eI2NPTunnelGateway:
i2p::tunnel::tunnels.PostTunnelData (msg);
break;
case eI2NPGarlic:
{
if (msg->from && msg->from->GetTunnelPool ())
msg->from->GetTunnelPool ()->ProcessGarlicMessage (msg);
else
i2p::context.ProcessGarlicMessage (msg);
break;
}
case eI2NPDatabaseStore:
case eI2NPDatabaseSearchReply:
case eI2NPDatabaseLookup:
// forward to netDb
i2p::data::netdb.PostI2NPMsg (msg);
break;
case eI2NPDeliveryStatus:
{
if (msg->from && msg->from->GetTunnelPool ())
msg->from->GetTunnelPool ()->ProcessDeliveryStatus (msg);
else
i2p::context.ProcessDeliveryStatusMessage (msg);
break;
}
case eI2NPVariableTunnelBuild:
case eI2NPVariableTunnelBuildReply:
case eI2NPTunnelBuild:
case eI2NPTunnelBuildReply:
case eI2NPShortTunnelBuild:
case eI2NPShortTunnelBuildReply:
// forward to tunnel thread
i2p::tunnel::tunnels.PostTunnelData (msg);
break;
default:
HandleI2NPMessage (msg->GetBuffer (), msg->GetLength ());
}
}
}
I2NPMessagesHandler::~I2NPMessagesHandler ()
{
Flush ();
}
void I2NPMessagesHandler::PutNextMessage (std::shared_ptr<I2NPMessage>&& msg)
{
if (msg)
{
switch (msg->GetTypeID ())
{
case eI2NPTunnelData:
m_TunnelMsgs.push_back (msg);
break;
case eI2NPTunnelGateway:
m_TunnelGatewayMsgs.push_back (msg);
break;
default:
HandleI2NPMessage (msg);
}
}
}
void I2NPMessagesHandler::Flush ()
{
if (!m_TunnelMsgs.empty ())
{
i2p::tunnel::tunnels.PostTunnelData (m_TunnelMsgs);
m_TunnelMsgs.clear ();
}
if (!m_TunnelGatewayMsgs.empty ())
{
i2p::tunnel::tunnels.PostTunnelData (m_TunnelGatewayMsgs);
m_TunnelGatewayMsgs.clear ();
}
}
}
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