I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#include <string.h>
#include <vector>
#include "Crypto.h"
#include "Log.h"
#include "TunnelBase.h"
#include "RouterContext.h"
#include "Destination.h"
#include "Datagram.h"
namespace i2p
{
namespace datagram
{
DatagramDestination::DatagramDestination (std::shared_ptr<i2p::client::ClientDestination> owner):
m_Owner (owner.get()),
m_CleanupTimer(owner->GetService()),
m_Receiver (nullptr)
{
ScheduleCleanup();
}
DatagramDestination::~DatagramDestination ()
{
m_CleanupTimer.cancel();
m_Sessions.clear();
}
void DatagramDestination::SendDatagramTo (const uint8_t * payload, size_t len, const i2p::data::IdentHash& ident, uint16_t fromPort, uint16_t toPort)
{
auto owner = m_Owner;
auto i = owner->GetIdentity();
uint8_t buf[MAX_DATAGRAM_SIZE];
auto identityLen = i->ToBuffer (buf, MAX_DATAGRAM_SIZE);
uint8_t * signature = buf + identityLen;
auto signatureLen = i->GetSignatureLen ();
uint8_t * buf1 = signature + signatureLen;
size_t headerLen = identityLen + signatureLen;
memcpy (buf1, payload, len);
if (i->GetSigningKeyType () == i2p::data::SIGNING_KEY_TYPE_DSA_SHA1)
{
uint8_t hash[32];
SHA256(buf1, len, hash);
owner->Sign (hash, 32, signature);
}
else
owner->Sign (buf1, len, signature);
auto msg = CreateDataMessage (buf, len + headerLen, fromPort, toPort);
auto session = ObtainSession(ident);
session->SendMsg(msg);
}
void DatagramDestination::HandleDatagram (uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len)
{
i2p::data::IdentityEx identity;
size_t identityLen = identity.FromBuffer (buf, len);
const uint8_t * signature = buf + identityLen;
size_t headerLen = identityLen + identity.GetSignatureLen ();
bool verified = false;
if (identity.GetSigningKeyType () == i2p::data::SIGNING_KEY_TYPE_DSA_SHA1)
{
uint8_t hash[32];
SHA256(buf + headerLen, len - headerLen, hash);
verified = identity.Verify (hash, 32, signature);
}
else
verified = identity.Verify (buf + headerLen, len - headerLen, signature);
if (verified)
{
auto it = m_ReceiversByPorts.find (toPort);
if (it != m_ReceiversByPorts.end ())
it->second (identity, fromPort, toPort, buf + headerLen, len -headerLen);
else if (m_Receiver != nullptr)
m_Receiver (identity, fromPort, toPort, buf + headerLen, len -headerLen);
else
LogPrint (eLogWarning, "Receiver for datagram is not set");
}
else
LogPrint (eLogWarning, "Datagram signature verification failed");
}
void DatagramDestination::HandleDataMessagePayload (uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len)
{
// unzip it
uint8_t uncompressed[MAX_DATAGRAM_SIZE];
size_t uncompressedLen = m_Inflator.Inflate (buf, len, uncompressed, MAX_DATAGRAM_SIZE);
if (uncompressedLen)
HandleDatagram (fromPort, toPort, uncompressed, uncompressedLen);
}
std::shared_ptr<I2NPMessage> DatagramDestination::CreateDataMessage (const uint8_t * payload, size_t len, uint16_t fromPort, uint16_t toPort)
{
auto msg = NewI2NPMessage ();
uint8_t * buf = msg->GetPayload ();
buf += 4; // reserve for length
size_t size = m_Deflator.Deflate (payload, len, buf, msg->maxLen - msg->len);
if (size)
{
htobe32buf (msg->GetPayload (), size); // length
htobe16buf (buf + 4, fromPort); // source port
htobe16buf (buf + 6, toPort); // destination port
buf[9] = i2p::client::PROTOCOL_TYPE_DATAGRAM; // datagram protocol
msg->len += size + 4;
msg->FillI2NPMessageHeader (eI2NPData);
}
else
msg = nullptr;
return msg;
}
void DatagramDestination::ScheduleCleanup()
{
m_CleanupTimer.expires_from_now(boost::posix_time::seconds(DATAGRAM_SESSION_CLEANUP_INTERVAL));
m_CleanupTimer.async_wait(std::bind(&DatagramDestination::HandleCleanUp, this, std::placeholders::_1));
}
void DatagramDestination::HandleCleanUp(const boost::system::error_code & ecode)
{
if(ecode)
return;
std::lock_guard<std::mutex> lock(m_SessionsMutex);
auto now = i2p::util::GetMillisecondsSinceEpoch();
LogPrint(eLogDebug, "DatagramDestination: clean up sessions");
std::vector<i2p::data::IdentHash> expiredSessions;
// for each session ...
for (auto & e : m_Sessions) {
// check if expired
if(now - e.second->LastActivity() >= DATAGRAM_SESSION_MAX_IDLE)
expiredSessions.push_back(e.first); // we are expired
}
// for each expired session ...
for (auto & ident : expiredSessions) {
// remove the expired session
LogPrint(eLogInfo, "DatagramDestination: expiring idle session with ", ident.ToBase32());
m_Sessions.erase(ident);
}
m_Owner->CleanupExpiredTags();
ScheduleCleanup();
}
std::shared_ptr<DatagramSession> DatagramDestination::ObtainSession(const i2p::data::IdentHash & ident)
{
std::shared_ptr<DatagramSession> session = nullptr;
std::lock_guard<std::mutex> lock(m_SessionsMutex);
auto itr = m_Sessions.find(ident);
if (itr == m_Sessions.end()) {
// not found, create new session
session = std::make_shared<DatagramSession>(m_Owner, ident);
m_Sessions[ident] = session;
} else {
session = itr->second;
}
return session;
}
DatagramSession::DatagramSession(i2p::client::ClientDestination * localDestination,
const i2p::data::IdentHash & remoteIdent) :
m_LocalDestination(localDestination),
m_RemoteIdentity(remoteIdent),
m_LastUse(i2p::util::GetMillisecondsSinceEpoch())
{
}
void DatagramSession::SendMsg(std::shared_ptr<I2NPMessage> msg)
{
// we used this session
m_LastUse = i2p::util::GetMillisecondsSinceEpoch();
// schedule send
m_LocalDestination->GetService().post(std::bind(&DatagramSession::HandleSend, this, msg));
}
void DatagramSession::HandleSend(std::shared_ptr<I2NPMessage> msg)
{
// do we have a routing session?
if(m_RoutingSession)
{
// do we have a routing path ?
auto routingPath = m_RoutingSession->GetSharedRoutingPath();
if(!routingPath)
{
LogPrint(eLogDebug, "DatagramSession: try getting new routing path");
// no routing path, try getting one
routingPath = GetNextRoutingPath();
if(routingPath) // remember the routing path if we got one
m_RoutingSession->SetSharedRoutingPath(routingPath);
}
// make sure we have a routing path
if (routingPath)
{
auto outboundTunnel = routingPath->outboundTunnel;
if (outboundTunnel)
{
if(outboundTunnel->IsEstablished())
{
// we have a routing path and routing session and the outbound tunnel we are using is good
// wrap message with routing session and send down routing path's outbound tunnel wrapped for the IBGW
auto m = m_RoutingSession->WrapSingleMessage(msg);
routingPath->outboundTunnel->SendTunnelDataMsg({i2p::tunnel::TunnelMessageBlock{
i2p::tunnel::eDeliveryTypeTunnel,
routingPath->remoteLease->tunnelGateway, routingPath->remoteLease->tunnelID,
m
}});
return;
}
}
}
}
// we couldn't send so let's try resetting the routing path and updating lease set
ResetRoutingPath();
UpdateLeaseSet(msg);
}
std::shared_ptr<i2p::garlic::GarlicRoutingPath> DatagramSession::GetNextRoutingPath()
{
std::shared_ptr<i2p::tunnel::OutboundTunnel> outboundTunnel = nullptr;
std::shared_ptr<i2p::garlic::GarlicRoutingPath> routingPath = nullptr;
// get existing routing path if we have one
if(m_RoutingSession)
routingPath = m_RoutingSession->GetSharedRoutingPath();
// do we have an existing outbound tunnel and routing path?
if(routingPath && routingPath->outboundTunnel)
{
// is the outbound tunnel we are using good?
if (routingPath->outboundTunnel->IsEstablished())
{
// ya so let's stick with it
outboundTunnel = routingPath->outboundTunnel;
}
else
outboundTunnel = m_LocalDestination->GetTunnelPool()->GetNextOutboundTunnel(routingPath->outboundTunnel); // no so we'll switch outbound tunnels
// don't reuse the old path as we are making a new one
routingPath = nullptr;
}
// do we have an outbound tunnel that works already ?
if(!outboundTunnel)
outboundTunnel = m_LocalDestination->GetTunnelPool()->GetNextOutboundTunnel(); // no, let's get a new outbound tunnel as we probably just started
if(outboundTunnel)
{
// get next available lease
auto lease = GetNextLease();
if(lease)
{
// we have a valid lease to use and an outbound tunnel
// create new routing path
uint32_t now = i2p::util::GetSecondsSinceEpoch();
routingPath = std::make_shared<i2p::garlic::GarlicRoutingPath>(i2p::garlic::GarlicRoutingPath{
outboundTunnel,
lease,
0,
now,
0
});
}
}
return routingPath;
}
void DatagramSession::ResetRoutingPath()
{
if(m_RoutingSession)
{
auto routingPath = m_RoutingSession->GetSharedRoutingPath();
if(routingPath && routingPath->remoteLease) // we have a remote lease already specified and a routing path
{
// get outbound tunnel on this path
auto outboundTunnel = routingPath->outboundTunnel;
// is this outbound tunnel there and established
if (outboundTunnel && outboundTunnel->IsEstablished())
m_InvalidIBGW.push_back(routingPath->remoteLease->tunnelGateway); // yes, let's mark remote lease as dead because the outbound tunnel seems fine
}
// reset the routing path
m_RoutingSession->SetSharedRoutingPath(nullptr);
}
}
std::shared_ptr<const i2p::data::Lease> DatagramSession::GetNextLease()
{
std::shared_ptr<const i2p::data::Lease> next = nullptr;
if(m_RemoteLeaseSet)
{
std::vector<i2p::data::IdentHash> exclude;
for(const auto & ident : m_InvalidIBGW)
exclude.push_back(ident);
// find get all leases that are not in our ban list
auto leases = m_RemoteLeaseSet->GetNonExpiredLeasesExcluding( [&exclude] (const i2p::data::Lease & l) -> bool {
if(exclude.size())
{
auto end = std::end(exclude);
return std::find_if(exclude.begin(), end, [l] ( const i2p::data::IdentHash & ident) -> bool {
return ident == l.tunnelGateway;
}) != end;
}
else
return false;
});
if(leases.size())
{
// pick random valid next lease
uint32_t idx = rand() % leases.size();
next = leases[idx];
}
}
return next;
}
void DatagramSession::UpdateLeaseSet(std::shared_ptr<I2NPMessage> msg)
{
LogPrint(eLogInfo, "DatagramSession: updating lease set");
m_LocalDestination->RequestDestination(m_RemoteIdentity, std::bind(&DatagramSession::HandleGotLeaseSet, this, std::placeholders::_1, msg));
}
void DatagramSession::HandleGotLeaseSet(std::shared_ptr<const i2p::data::LeaseSet> remoteIdent, std::shared_ptr<I2NPMessage> msg)
{
if(remoteIdent) {
// update routing session
if(m_RoutingSession)
m_RoutingSession = nullptr;
m_RoutingSession = m_LocalDestination->GetRoutingSession(remoteIdent, true);
// clear invalid IBGW as we have a new lease set
m_InvalidIBGW.clear();
m_RemoteLeaseSet = remoteIdent;
// send the message that was queued if it was provided
if(msg)
HandleSend(msg);
}
}
}
}