I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#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, 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 = NewI2NPMessage ();
*msg->GetPayload () = numRecords;
msg->len += numRecords*sizeof (I2NPBuildRequestRecordElGamalEncrypted) + 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
I2NPBuildRequestRecordElGamalEncrypted * records = (I2NPBuildRequestRecordElGamalEncrypted *)(msg->GetPayload () + 1);
TunnelHopConfig * hop = m_Config->GetFirstHop ();
int i = 0;
while (hop)
{
int idx = recordIndicies[i];
EncryptBuildRequestRecord (*hop->router,
CreateBuildRequestRecord (hop->router->GetIdentHash (),
hop->tunnelID,
hop->nextRouter->GetIdentHash (),
hop->nextTunnelID,
hop->layerKey, hop->ivKey,
hop->replyKey, hop->replyIV,
hop->next ? rnd.GenerateWord32 () : replyMsgID, // we set replyMsgID for last hop only
hop->isGateway, hop->isEndpoint),
records[idx]);
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 ((uint8_t *)(records + idx), sizeof (records[idx]));
}
// 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);
decryption.Decrypt((uint8_t *)&records[hop1->recordIndex],
sizeof (I2NPBuildRequestRecordElGamalEncrypted),
(uint8_t *)&records[hop1->recordIndex]);
hop1 = hop1->next;
}
hop = hop->prev;
}
FillI2NPMessageHeader (msg, eI2NPVariableTunnelBuild);
// send message
if (outboundTunnel)
outboundTunnel->SendTunnelDataMsg (GetNextIdentHash (), 0, msg);
else
i2p::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*sizeof (I2NPBuildResponseRecord);
decryption.SetIV (hop->replyIV);
decryption.Decrypt(record, sizeof (I2NPBuildResponseRecord), 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)
{
I2NPBuildResponseRecord * record = (I2NPBuildResponseRecord *)(msg + 1 + hop->recordIndex*sizeof (I2NPBuildResponseRecord));
LogPrint ("Ret code=", (int)record->ret);
if (record->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 InboundTunnel::HandleTunnelDataMsg (I2NPMessage * msg)
{
if (IsFailed ()) SetState (eTunnelStateEstablished); // incoming messages means a tunnel is alive
msg->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 (std::vector<TunnelMessageBlock> msgs)
{
std::unique_lock<std::mutex> l(m_SendMutex);
for (auto& it : msgs)
m_Gateway.PutTunnelDataMsg (it);
m_Gateway.SendBuffer ();
}
Tunnels tunnels;
Tunnels::Tunnels (): m_IsRunning (false), m_IsTunnelCreated (false),
m_NextReplyMsgID (555), m_Thread (nullptr), m_ExploratoryPool (nullptr)
{
}
Tunnels::~Tunnels ()
{
for (auto& it : m_OutboundTunnels)
delete it;
m_OutboundTunnels.clear ();
for (auto& it : m_InboundTunnels)
delete it.second;
m_InboundTunnels.clear ();
for (auto& it : m_TransitTunnels)
delete it.second;
m_TransitTunnels.clear ();
/*for (auto& it : m_PendingTunnels)
delete it.second;
m_PendingTunnels.clear ();*/
for (auto& it: m_Pools)
delete it.second;
m_Pools.clear ();
}
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;
}
Tunnel * Tunnels::GetPendingTunnel (uint32_t replyMsgID)
{
auto it = m_PendingTunnels.find(replyMsgID);
if (it != m_PendingTunnels.end ())
{
it->second->SetState (eTunnelStateBuildReplyReceived);
return it->second;
}
return nullptr;
}
InboundTunnel * Tunnels::GetNextInboundTunnel ()
{
InboundTunnel * tunnel = nullptr;
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;
}
OutboundTunnel * Tunnels::GetNextOutboundTunnel ()
{
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
uint32_t ind = rnd.GenerateWord32 (0, m_OutboundTunnels.size () - 1), i = 0;
OutboundTunnel * tunnel = nullptr;
for (auto it: m_OutboundTunnels)
{
if (it->IsEstablished ())
{
tunnel = it;
i++;
}
if (i > ind && tunnel) break;
}
return tunnel;
}
TunnelPool * Tunnels::CreateTunnelPool (i2p::data::LocalDestination& localDestination, int numHops)
{
auto pool = new TunnelPool (localDestination, numHops);
m_Pools[pool->GetIdentHash ()] = pool;
return pool;
}
void Tunnels::DeleteTunnelPool (TunnelPool * pool)
{
if (pool)
{
m_Pools.erase (pool->GetIdentHash ());
delete pool;
}
}
void Tunnels::AddTransitTunnel (TransitTunnel * tunnel)
{
std::unique_lock<std::mutex> l(m_TransitTunnelsMutex);
m_TransitTunnels[tunnel->GetTunnelID ()] = 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
while (msg)
{
uint32_t tunnelID = be32toh (*(uint32_t *)msg->GetPayload ());
InboundTunnel * tunnel = GetInboundTunnel (tunnelID);
if (tunnel)
tunnel->HandleTunnelDataMsg (msg);
else
{
TransitTunnel * transitTunnel = GetTransitTunnel (tunnelID);
if (transitTunnel)
transitTunnel->HandleTunnelDataMsg (msg);
else
{
LogPrint ("Tunnel ", tunnelID, " not found");
i2p::DeleteI2NPMessage (msg);
}
}
msg = m_Queue.Get ();
}
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::ManageTunnels ()
{
// check pending tunnel. delete failed or timeout
uint64_t ts = i2p::util::GetSecondsSinceEpoch ();
for (auto it = m_PendingTunnels.begin (); it != m_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");
delete tunnel;
it = m_PendingTunnels.erase (it);
}
else
it++;
break;
case eTunnelStateBuildFailed:
LogPrint ("Pending tunnel build request ", it->first, " failed. Deleted");
delete tunnel;
it = m_PendingTunnels.erase (it);
break;
case eTunnelStateBuildReplyReceived:
// intermidiate state, will be either established of build failed
it++;
break;
default:
it = m_PendingTunnels.erase (it);
}
}
ManageInboundTunnels ();
ManageOutboundTunnels ();
ManageTransitTunnels ();
ManageTunnelPools ();
}
void Tunnels::ManageOutboundTunnels ()
{
uint64_t ts = i2p::util::GetSecondsSinceEpoch ();
{
std::unique_lock<std::mutex> l(m_OutboundTunnelsMutex);
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);
delete tunnel;
}
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
InboundTunnel * inboundTunnel = GetNextInboundTunnel ();
if (!inboundTunnel) return;
LogPrint ("Creating one hop outbound tunnel...");
CreateTunnel<OutboundTunnel> (
new TunnelConfig (std::vector<const i2p::data::RouterInfo *>
{
i2p::data::netdb.GetRandomRouter ()
},
inboundTunnel->GetTunnelConfig ()));
}
}
void Tunnels::ManageInboundTunnels ()
{
uint64_t ts = i2p::util::GetSecondsSinceEpoch ();
{
std::unique_lock<std::mutex> l(m_InboundTunnelsMutex);
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);
delete tunnel;
}
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-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<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)
{
LogPrint ("Transit tunnel ", it->second->GetTunnelID (), " expired");
auto tmp = it->second;
{
std::unique_lock<std::mutex> l(m_TransitTunnelsMutex);
it = m_TransitTunnels.erase (it);
}
delete tmp;
}
else
it++;
}
}
void Tunnels::ManageTunnelPools ()
{
for (auto& it: m_Pools)
{
it.second->CreateTunnels ();
it.second->TestTunnels ();
}
}
void Tunnels::PostTunnelData (I2NPMessage * msg)
{
if (msg) m_Queue.Put (msg);
}
template<class TTunnel>
TTunnel * Tunnels::CreateTunnel (TunnelConfig * config, OutboundTunnel * outboundTunnel)
{
TTunnel * newTunnel = new TTunnel (config);
m_PendingTunnels[m_NextReplyMsgID] = newTunnel;
newTunnel->Build (m_NextReplyMsgID, outboundTunnel);
m_NextReplyMsgID++; // TODO: should be atomic
return newTunnel;
}
void Tunnels::AddOutboundTunnel (OutboundTunnel * newTunnel)
{
std::unique_lock<std::mutex> l(m_OutboundTunnelsMutex);
m_OutboundTunnels.push_back (newTunnel);
auto pool = newTunnel->GetTunnelPool ();
if (pool)
pool->TunnelCreated (newTunnel);
}
void Tunnels::AddInboundTunnel (InboundTunnel * newTunnel)
{
std::unique_lock<std::mutex> l(m_InboundTunnelsMutex);
m_InboundTunnels[newTunnel->GetTunnelID ()] = newTunnel;
auto pool = newTunnel->GetTunnelPool ();
if (!pool)
{
// build symmetric outbound tunnel
CreateTunnel<OutboundTunnel> (newTunnel->GetTunnelConfig ()->Invert (), GetNextOutboundTunnel ());
}
else
pool->TunnelCreated (newTunnel);
}
void Tunnels::CreateZeroHopsInboundTunnel ()
{
CreateTunnel<InboundTunnel> (
new TunnelConfig (std::vector<const i2p::data::RouterInfo *>
{
&i2p::context.GetRouterInfo ()
}));
}
}
}