I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <string.h>
#include "I2PEndian.h"
#include <thread>
#include <algorithm>
#include <vector>
#include <cryptopp/sha.h>
#include "RouterContext.h"
#include "Log.h"
#include "Timestamp.h"
#include "I2NPProtocol.h"
#include "Transports.h"
#include "NetDb.h"
#include "Tunnel.h"
namespace i2p
{
namespace tunnel
{
Tunnel::Tunnel (TunnelConfig * config):
m_Config (config), m_Pool (nullptr), m_State (eTunnelStatePending)
{
}
Tunnel::~Tunnel ()
{
delete m_Config;
}
void Tunnel::Build (uint32_t replyMsgID, std::shared_ptr<OutboundTunnel> outboundTunnel)
{
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
auto numHops = m_Config->GetNumHops ();
int numRecords = numHops <= STANDARD_NUM_RECORDS ? STANDARD_NUM_RECORDS : numHops;
I2NPMessage * msg = NewI2NPShortMessage ();
*msg->GetPayload () = numRecords;
msg->len += numRecords*TUNNEL_BUILD_RECORD_SIZE + 1;
// shuffle records
std::vector<int> recordIndicies;
for (int i = 0; i < numRecords; i++) recordIndicies.push_back(i);
std::random_shuffle (recordIndicies.begin(), recordIndicies.end());
// create real records
uint8_t * records = msg->GetPayload () + 1;
TunnelHopConfig * hop = m_Config->GetFirstHop ();
int i = 0;
while (hop)
{
int idx = recordIndicies[i];
hop->CreateBuildRequestRecord (records + idx*TUNNEL_BUILD_RECORD_SIZE,
hop->next ? rnd.GenerateWord32 () : replyMsgID); // we set replyMsgID for last hop only
hop->recordIndex = idx;
i++;
hop = hop->next;
}
// fill up fake records with random data
for (int i = numHops; i < numRecords; i++)
{
int idx = recordIndicies[i];
rnd.GenerateBlock (records + idx*TUNNEL_BUILD_RECORD_SIZE, TUNNEL_BUILD_RECORD_SIZE);
}
// decrypt real records
i2p::crypto::CBCDecryption decryption;
hop = m_Config->GetLastHop ()->prev;
while (hop)
{
decryption.SetKey (hop->replyKey);
// decrypt records after current hop
TunnelHopConfig * hop1 = hop->next;
while (hop1)
{
decryption.SetIV (hop->replyIV);
uint8_t * record = records + hop1->recordIndex*TUNNEL_BUILD_RECORD_SIZE;
decryption.Decrypt(record, TUNNEL_BUILD_RECORD_SIZE, record);
hop1 = hop1->next;
}
hop = hop->prev;
}
FillI2NPMessageHeader (msg, eI2NPVariableTunnelBuild);
// send message
if (outboundTunnel)
outboundTunnel->SendTunnelDataMsg (GetNextIdentHash (), 0, msg);
else
i2p::transport::transports.SendMessage (GetNextIdentHash (), msg);
}
bool Tunnel::HandleTunnelBuildResponse (uint8_t * msg, size_t len)
{
LogPrint ("TunnelBuildResponse ", (int)msg[0], " records.");
i2p::crypto::CBCDecryption decryption;
TunnelHopConfig * hop = m_Config->GetLastHop ();
while (hop)
{
decryption.SetKey (hop->replyKey);
// decrypt records before and including current hop
TunnelHopConfig * hop1 = hop;
while (hop1)
{
auto idx = hop1->recordIndex;
if (idx >= 0 && idx < msg[0])
{
uint8_t * record = msg + 1 + idx*TUNNEL_BUILD_RECORD_SIZE;
decryption.SetIV (hop->replyIV);
decryption.Decrypt(record, TUNNEL_BUILD_RECORD_SIZE, record);
}
else
LogPrint ("Tunnel hop index ", idx, " is out of range");
hop1 = hop1->prev;
}
hop = hop->prev;
}
bool established = true;
hop = m_Config->GetFirstHop ();
while (hop)
{
const uint8_t * record = msg + 1 + hop->recordIndex*TUNNEL_BUILD_RECORD_SIZE;
uint8_t ret = record[BUILD_RESPONSE_RECORD_RET_OFFSET];
LogPrint ("Ret code=", (int)ret);
hop->router->GetProfile ()->TunnelBuildResponse (ret);
if (ret)
// if any of participants declined the tunnel is not established
established = false;
hop = hop->next;
}
if (established)
{
// change reply keys to layer keys
hop = m_Config->GetFirstHop ();
while (hop)
{
hop->decryption.SetKeys (hop->layerKey, hop->ivKey);
hop = hop->next;
}
}
if (established) m_State = eTunnelStateEstablished;
return established;
}
void Tunnel::EncryptTunnelMsg (I2NPMessage * tunnelMsg)
{
uint8_t * payload = tunnelMsg->GetPayload () + 4;
TunnelHopConfig * hop = m_Config->GetLastHop ();
while (hop)
{
hop->decryption.Decrypt (payload);
hop = hop->prev;
}
}
void Tunnel::SendTunnelDataMsg (i2p::I2NPMessage * msg)
{
LogPrint (eLogInfo, "Can't send I2NP messages without delivery instructions");
DeleteI2NPMessage (msg);
}
void InboundTunnel::HandleTunnelDataMsg (I2NPMessage * msg)
{
if (IsFailed ()) SetState (eTunnelStateEstablished); // incoming messages means a tunnel is alive
msg->from = shared_from_this ();
EncryptTunnelMsg (msg);
m_Endpoint.HandleDecryptedTunnelDataMsg (msg);
}
void OutboundTunnel::SendTunnelDataMsg (const uint8_t * gwHash, uint32_t gwTunnel, i2p::I2NPMessage * msg)
{
TunnelMessageBlock block;
if (gwHash)
{
block.hash = gwHash;
if (gwTunnel)
{
block.deliveryType = eDeliveryTypeTunnel;
block.tunnelID = gwTunnel;
}
else
block.deliveryType = eDeliveryTypeRouter;
}
else
block.deliveryType = eDeliveryTypeLocal;
block.data = msg;
std::unique_lock<std::mutex> l(m_SendMutex);
m_Gateway.SendTunnelDataMsg (block);
}
void OutboundTunnel::SendTunnelDataMsg (const std::vector<TunnelMessageBlock>& msgs)
{
std::unique_lock<std::mutex> l(m_SendMutex);
for (auto& it : msgs)
m_Gateway.PutTunnelDataMsg (it);
m_Gateway.SendBuffer ();
}
void OutboundTunnel::HandleTunnelDataMsg (i2p::I2NPMessage * tunnelMsg)
{
LogPrint (eLogError, "Incoming message for outbound tunnel ", GetTunnelID ());
DeleteI2NPMessage (tunnelMsg);
}
Tunnels tunnels;
Tunnels::Tunnels (): m_IsRunning (false), m_Thread (nullptr),
m_NumSuccesiveTunnelCreations (0), m_NumFailedTunnelCreations (0)
{
}
Tunnels::~Tunnels ()
{
for (auto& it : m_TransitTunnels)
delete it.second;
m_TransitTunnels.clear ();
}
std::shared_ptr<InboundTunnel> Tunnels::GetInboundTunnel (uint32_t tunnelID)
{
auto it = m_InboundTunnels.find(tunnelID);
if (it != m_InboundTunnels.end ())
return it->second;
return nullptr;
}
TransitTunnel * Tunnels::GetTransitTunnel (uint32_t tunnelID)
{
auto it = m_TransitTunnels.find(tunnelID);
if (it != m_TransitTunnels.end ())
return it->second;
return nullptr;
}
std::shared_ptr<InboundTunnel> Tunnels::GetPendingInboundTunnel (uint32_t replyMsgID)
{
return GetPendingTunnel (replyMsgID, m_PendingInboundTunnels);
}
std::shared_ptr<OutboundTunnel> Tunnels::GetPendingOutboundTunnel (uint32_t replyMsgID)
{
return GetPendingTunnel (replyMsgID, m_PendingOutboundTunnels);
}
template<class TTunnel>
std::shared_ptr<TTunnel> Tunnels::GetPendingTunnel (uint32_t replyMsgID, const std::map<uint32_t, std::shared_ptr<TTunnel> >& pendingTunnels)
{
auto it = pendingTunnels.find(replyMsgID);
if (it != pendingTunnels.end () && it->second->GetState () == eTunnelStatePending)
{
it->second->SetState (eTunnelStateBuildReplyReceived);
return it->second;
}
return nullptr;
}
std::shared_ptr<InboundTunnel> Tunnels::GetNextInboundTunnel ()
{
std::shared_ptr<InboundTunnel> tunnel;
size_t minReceived = 0;
for (auto it : m_InboundTunnels)
{
if (!it.second->IsEstablished ()) continue;
if (!tunnel || it.second->GetNumReceivedBytes () < minReceived)
{
tunnel = it.second;
minReceived = it.second->GetNumReceivedBytes ();
}
}
return tunnel;
}
std::shared_ptr<OutboundTunnel> Tunnels::GetNextOutboundTunnel ()
{
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
uint32_t ind = rnd.GenerateWord32 (0, m_OutboundTunnels.size () - 1), i = 0;
std::shared_ptr<OutboundTunnel> tunnel;
for (auto it: m_OutboundTunnels)
{
if (it->IsEstablished ())
{
tunnel = it;
i++;
}
if (i > ind && tunnel) break;
}
return tunnel;
}
std::shared_ptr<TunnelPool> Tunnels::CreateTunnelPool (i2p::garlic::GarlicDestination * localDestination, int numInboundHops, int numOutboundHops)
{
auto pool = std::make_shared<TunnelPool> (localDestination, numInboundHops, numOutboundHops);
std::unique_lock<std::mutex> l(m_PoolsMutex);
m_Pools.push_back (pool);
return pool;
}
void Tunnels::DeleteTunnelPool (std::shared_ptr<TunnelPool> pool)
{
if (pool)
{
StopTunnelPool (pool);
{
std::unique_lock<std::mutex> l(m_PoolsMutex);
m_Pools.remove (pool);
}
}
}
void Tunnels::StopTunnelPool (std::shared_ptr<TunnelPool> pool)
{
if (pool)
{
pool->SetActive (false);
pool->DetachTunnels ();
}
}
void Tunnels::AddTransitTunnel (TransitTunnel * tunnel)
{
std::unique_lock<std::mutex> l(m_TransitTunnelsMutex);
if (!m_TransitTunnels.insert (std::make_pair (tunnel->GetTunnelID (), tunnel)).second)
{
LogPrint (eLogError, "Transit tunnel ", tunnel->GetTunnelID (), " already exists");
delete tunnel;
}
}
void Tunnels::Start ()
{
m_IsRunning = true;
m_Thread = new std::thread (std::bind (&Tunnels::Run, this));
}
void Tunnels::Stop ()
{
m_IsRunning = false;
m_Queue.WakeUp ();
if (m_Thread)
{
m_Thread->join ();
delete m_Thread;
m_Thread = 0;
}
}
void Tunnels::Run ()
{
std::this_thread::sleep_for (std::chrono::seconds(1)); // wait for other parts are ready
uint64_t lastTs = 0;
while (m_IsRunning)
{
try
{
I2NPMessage * msg = m_Queue.GetNextWithTimeout (1000); // 1 sec
if (msg)
{
uint32_t prevTunnelID = 0, tunnelID = 0;
TunnelBase * prevTunnel = nullptr;
do
{
TunnelBase * tunnel = nullptr;
uint8_t typeID = msg->GetTypeID ();
switch (typeID)
{
case eI2NPTunnelData:
case eI2NPTunnelGateway:
{
tunnelID = bufbe32toh (msg->GetPayload ());
if (tunnelID == prevTunnelID)
tunnel = prevTunnel;
else if (prevTunnel)
prevTunnel->FlushTunnelDataMsgs ();
if (!tunnel && typeID == eI2NPTunnelData)
tunnel = GetInboundTunnel (tunnelID).get ();
if (!tunnel)
tunnel = GetTransitTunnel (tunnelID);
if (tunnel)
{
if (typeID == eI2NPTunnelData)
tunnel->HandleTunnelDataMsg (msg);
else // tunnel gateway assumed
HandleTunnelGatewayMsg (tunnel, msg);
}
else
{
LogPrint (eLogWarning, "Tunnel ", tunnelID, " not found");
DeleteI2NPMessage (msg);
}
break;
}
case eI2NPVariableTunnelBuild:
case eI2NPVariableTunnelBuildReply:
case eI2NPTunnelBuild:
case eI2NPTunnelBuildReply:
{
HandleI2NPMessage (msg->GetBuffer (), msg->GetLength ());
DeleteI2NPMessage (msg);
break;
}
default:
{
LogPrint (eLogError, "Unexpected messsage type ", (int)typeID);
DeleteI2NPMessage (msg);
}
}
msg = m_Queue.Get ();
if (msg)
{
prevTunnelID = tunnelID;
prevTunnel = tunnel;
}
else if (tunnel)
tunnel->FlushTunnelDataMsgs ();
}
while (msg);
}
uint64_t ts = i2p::util::GetSecondsSinceEpoch ();
if (ts - lastTs >= 15) // manage tunnels every 15 seconds
{
ManageTunnels ();
lastTs = ts;
}
}
catch (std::exception& ex)
{
LogPrint ("Tunnels: ", ex.what ());
}
}
}
void Tunnels::HandleTunnelGatewayMsg (TunnelBase * tunnel, I2NPMessage * msg)
{
if (!tunnel)
{
LogPrint (eLogError, "Missing tunnel for TunnelGateway");
i2p::DeleteI2NPMessage (msg);
return;
}
const uint8_t * payload = msg->GetPayload ();
uint16_t len = bufbe16toh(payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET);
// we make payload as new I2NP message to send
msg->offset += I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE;
msg->len = msg->offset + len;
auto typeID = msg->GetTypeID ();
LogPrint (eLogDebug, "TunnelGateway of ", (int)len, " bytes for tunnel ", tunnel->GetTunnelID (), ". Msg type ", (int)typeID);
if (typeID == eI2NPDatabaseStore || typeID == eI2NPDatabaseSearchReply)
{
// transit DatabaseStore my contain new/updated RI
// or DatabaseSearchReply with new routers
auto ds = NewI2NPMessage ();
*ds = *msg;
i2p::data::netdb.PostI2NPMsg (ds);
}
tunnel->SendTunnelDataMsg (msg);
}
void Tunnels::ManageTunnels ()
{
ManagePendingTunnels ();
ManageInboundTunnels ();
ManageOutboundTunnels ();
ManageTransitTunnels ();
ManageTunnelPools ();
}
void Tunnels::ManagePendingTunnels ()
{
ManagePendingTunnels (m_PendingInboundTunnels);
ManagePendingTunnels (m_PendingOutboundTunnels);
}
template<class PendingTunnels>
void Tunnels::ManagePendingTunnels (PendingTunnels& pendingTunnels)
{
// check pending tunnel. delete failed or timeout
uint64_t ts = i2p::util::GetSecondsSinceEpoch ();
for (auto it = pendingTunnels.begin (); it != pendingTunnels.end ();)
{
auto tunnel = it->second;
switch (tunnel->GetState ())
{
case eTunnelStatePending:
if (ts > tunnel->GetCreationTime () + TUNNEL_CREATION_TIMEOUT)
{
LogPrint ("Pending tunnel build request ", it->first, " timeout. Deleted");
// update stats
auto config = tunnel->GetTunnelConfig ();
if (config)
{
auto hop = config->GetFirstHop ();
while (hop)
{
if (hop->router)
hop->router->GetProfile ()->TunnelNonReplied ();
hop = hop->next;
}
}
// delete
it = pendingTunnels.erase (it);
m_NumFailedTunnelCreations++;
}
else
it++;
break;
case eTunnelStateBuildFailed:
LogPrint ("Pending tunnel build request ", it->first, " failed. Deleted");
it = pendingTunnels.erase (it);
m_NumFailedTunnelCreations++;
break;
case eTunnelStateBuildReplyReceived:
// intermediate state, will be either established of build failed
it++;
break;
default:
// success
it = pendingTunnels.erase (it);
m_NumSuccesiveTunnelCreations++;
}
}
}
void Tunnels::ManageOutboundTunnels ()
{
uint64_t ts = i2p::util::GetSecondsSinceEpoch ();
{
for (auto it = m_OutboundTunnels.begin (); it != m_OutboundTunnels.end ();)
{
auto tunnel = *it;
if (ts > tunnel->GetCreationTime () + TUNNEL_EXPIRATION_TIMEOUT)
{
LogPrint ("Tunnel ", tunnel->GetTunnelID (), " expired");
{
auto pool = tunnel->GetTunnelPool ();
if (pool)
pool->TunnelExpired (tunnel);
}
it = m_OutboundTunnels.erase (it);
}
else
{
if (tunnel->IsEstablished () && ts + TUNNEL_EXPIRATION_THRESHOLD > tunnel->GetCreationTime () + TUNNEL_EXPIRATION_TIMEOUT)
tunnel->SetState (eTunnelStateExpiring);
it++;
}
}
}
if (m_OutboundTunnels.size () < 5)
{
// trying to create one more oubound tunnel
auto inboundTunnel = GetNextInboundTunnel ();
if (!inboundTunnel) return;
LogPrint ("Creating one hop outbound tunnel...");
CreateTunnel<OutboundTunnel> (
new TunnelConfig (std::vector<std::shared_ptr<const i2p::data::RouterInfo> >
{
i2p::data::netdb.GetRandomRouter ()
},
inboundTunnel->GetTunnelConfig ()));
}
}
void Tunnels::ManageInboundTunnels ()
{
uint64_t ts = i2p::util::GetSecondsSinceEpoch ();
{
for (auto it = m_InboundTunnels.begin (); it != m_InboundTunnels.end ();)
{
auto tunnel = it->second;
if (ts > tunnel->GetCreationTime () + TUNNEL_EXPIRATION_TIMEOUT)
{
LogPrint ("Tunnel ", tunnel->GetTunnelID (), " expired");
{
auto pool = tunnel->GetTunnelPool ();
if (pool)
pool->TunnelExpired (tunnel);
}
it = m_InboundTunnels.erase (it);
}
else
{
if (tunnel->IsEstablished () && ts + TUNNEL_EXPIRATION_THRESHOLD > tunnel->GetCreationTime () + TUNNEL_EXPIRATION_TIMEOUT)
tunnel->SetState (eTunnelStateExpiring);
it++;
}
}
}
if (m_InboundTunnels.empty ())
{
LogPrint ("Creating zero hops inbound tunnel...");
CreateZeroHopsInboundTunnel ();
if (!m_ExploratoryPool)
m_ExploratoryPool = CreateTunnelPool (&i2p::context, 2, 2); // 2-hop exploratory
return;
}
if (m_OutboundTunnels.empty () || m_InboundTunnels.size () < 5)
{
// trying to create one more inbound tunnel
LogPrint ("Creating one hop inbound tunnel...");
CreateTunnel<InboundTunnel> (
new TunnelConfig (std::vector<std::shared_ptr<const i2p::data::RouterInfo> >
{
i2p::data::netdb.GetRandomRouter ()
}));
}
}
void Tunnels::ManageTransitTunnels ()
{
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
for (auto it = m_TransitTunnels.begin (); it != m_TransitTunnels.end ();)
{
if (ts > it->second->GetCreationTime () + TUNNEL_EXPIRATION_TIMEOUT)
{
auto tmp = it->second;
LogPrint ("Transit tunnel ", tmp->GetTunnelID (), " expired");
{
std::unique_lock<std::mutex> l(m_TransitTunnelsMutex);
it = m_TransitTunnels.erase (it);
}
delete tmp;
}
else
it++;
}
}
void Tunnels::ManageTunnelPools ()
{
std::unique_lock<std::mutex> l(m_PoolsMutex);
for (auto it: m_Pools)
{
auto pool = it;
if (pool && pool->IsActive ())
{
pool->CreateTunnels ();
pool->TestTunnels ();
}
}
}
void Tunnels::PostTunnelData (I2NPMessage * msg)
{
if (msg) m_Queue.Put (msg);
}
void Tunnels::PostTunnelData (const std::vector<I2NPMessage *>& msgs)
{
m_Queue.Put (msgs);
}
template<class TTunnel>
std::shared_ptr<TTunnel> Tunnels::CreateTunnel (TunnelConfig * config, std::shared_ptr<OutboundTunnel> outboundTunnel)
{
auto newTunnel = std::make_shared<TTunnel> (config);
uint32_t replyMsgID = i2p::context.GetRandomNumberGenerator ().GenerateWord32 ();
AddPendingTunnel (replyMsgID, newTunnel);
newTunnel->Build (replyMsgID, outboundTunnel);
return newTunnel;
}
void Tunnels::AddPendingTunnel (uint32_t replyMsgID, std::shared_ptr<InboundTunnel> tunnel)
{
m_PendingInboundTunnels[replyMsgID] = tunnel;
}
void Tunnels::AddPendingTunnel (uint32_t replyMsgID, std::shared_ptr<OutboundTunnel> tunnel)
{
m_PendingOutboundTunnels[replyMsgID] = tunnel;
}
void Tunnels::AddOutboundTunnel (std::shared_ptr<OutboundTunnel> newTunnel)
{
m_OutboundTunnels.push_back (newTunnel);
auto pool = newTunnel->GetTunnelPool ();
if (pool && pool->IsActive ())
pool->TunnelCreated (newTunnel);
else
newTunnel->SetTunnelPool (nullptr);
}
void Tunnels::AddInboundTunnel (std::shared_ptr<InboundTunnel> newTunnel)
{
m_InboundTunnels[newTunnel->GetTunnelID ()] = newTunnel;
auto pool = newTunnel->GetTunnelPool ();
if (!pool)
{
// build symmetric outbound tunnel
CreateTunnel<OutboundTunnel> (newTunnel->GetTunnelConfig ()->Invert (), GetNextOutboundTunnel ());
}
else
{
if (pool->IsActive ())
pool->TunnelCreated (newTunnel);
else
newTunnel->SetTunnelPool (nullptr);
}
}
void Tunnels::CreateZeroHopsInboundTunnel ()
{
CreateTunnel<InboundTunnel> (
new TunnelConfig (std::vector<std::shared_ptr<const i2p::data::RouterInfo> >
{
i2p::context.GetSharedRouterInfo ()
}));
}
int Tunnels::GetTransitTunnelsExpirationTimeout ()
{
int timeout = 0;
uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
std::unique_lock<std::mutex> l(m_TransitTunnelsMutex);
for (auto it: m_TransitTunnels)
{
int t = it.second->GetCreationTime () + TUNNEL_EXPIRATION_TIMEOUT - ts;
if (t > timeout) timeout = t;
}
return timeout;
}
}
}