I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#ifndef DATAGRAM_H__
#define DATAGRAM_H__
#include <inttypes.h>
#include <memory>
#include <functional>
#include <map>
#include "Base.h"
#include "Identity.h"
#include "LeaseSet.h"
#include "I2NPProtocol.h"
#include "Garlic.h"
namespace i2p
{
namespace client
{
class ClientDestination;
}
namespace datagram
{
// seconds interval for cleanup timer
const int DATAGRAM_SESSION_CLEANUP_INTERVAL = 3;
// milliseconds for max session idle time
const uint64_t DATAGRAM_SESSION_MAX_IDLE = 10 * 60 * 1000;
// milliseconds for how long we try sticking to a dead routing path before trying to switch
const uint64_t DATAGRAM_SESSION_PATH_TIMEOUT = 5000;
// milliseconds interval a routing path is used before switching
const uint64_t DATAGRAM_SESSION_PATH_SWITCH_INTERVAL = 60 * 1000;
// milliseconds before lease expire should we try switching leases
const uint64_t DATAGRAM_SESSION_LEASE_HANDOVER_WINDOW = 10 * 1000;
// milliseconds fudge factor for leases handover
const uint64_t DATAGRAM_SESSION_LEASE_HANDOVER_FUDGE = 1000;
class DatagramSession
{
public:
DatagramSession(i2p::client::ClientDestination * localDestination,
const i2p::data::IdentHash & remoteIdent);
/** send an i2np message to remote endpoint for this session */
void SendMsg(std::shared_ptr<I2NPMessage> msg);
/** get the last time in milliseconds for when we used this datagram session */
uint64_t LastActivity() const { return m_LastUse; }
/** get the last time in milliseconds when we successfully sent data */
uint64_t LastSuccess() const { return m_LastSuccess; }
struct Info
{
const i2p::data::IdentHash * IBGW;
const i2p::data::IdentHash * OBEP;
const uint64_t activity;
const uint64_t success;
~Info()
{
if(IBGW) delete IBGW;
if(OBEP) delete OBEP;
}
};
Info GetSessionInfo() const;
private:
/** update our routing path we are using, mark that we have changed paths */
void UpdateRoutingPath(const std::shared_ptr<i2p::garlic::GarlicRoutingPath> & path);
/** return true if we should switch routing paths because of path lifetime or timeout otherwise false */
bool ShouldUpdateRoutingPath() const;
/** return true if we should switch the lease for out routing path otherwise return false */
bool ShouldSwitchLease() const;
/** get next usable routing path, try reusing outbound tunnels */
std::shared_ptr<i2p::garlic::GarlicRoutingPath> GetNextRoutingPath();
/**
* mark current routing path as invalid and clear it
* if the outbound tunnel we were using was okay don't use the IBGW in the routing path's lease next time
*/
void ResetRoutingPath();
/** get next usable lease, does not fetch or update if expired or have no lease set */
std::shared_ptr<const i2p::data::Lease> GetNextLease();
void HandleSend(std::shared_ptr<I2NPMessage> msg);
void HandleGotLeaseSet(std::shared_ptr<const i2p::data::LeaseSet> remoteIdent,
std::shared_ptr<I2NPMessage> msg);
void UpdateLeaseSet(std::shared_ptr<I2NPMessage> msg=nullptr);
private:
i2p::client::ClientDestination * m_LocalDestination;
i2p::data::IdentHash m_RemoteIdentity;
std::shared_ptr<i2p::garlic::GarlicRoutingSession> m_RoutingSession;
// Ident hash of IBGW that are invalid
std::vector<i2p::data::IdentHash> m_InvalidIBGW;
std::shared_ptr<const i2p::data::LeaseSet> m_RemoteLeaseSet;
uint64_t m_LastUse;
uint64_t m_LastPathChange;
uint64_t m_LastSuccess;
};
const size_t MAX_DATAGRAM_SIZE = 32768;
class DatagramDestination
{
typedef std::function<void (const i2p::data::IdentityEx& from, uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len)> Receiver;
public:
DatagramDestination (std::shared_ptr<i2p::client::ClientDestination> owner);
~DatagramDestination ();
void SendDatagramTo (const uint8_t * payload, size_t len, const i2p::data::IdentHash& ident, uint16_t fromPort = 0, uint16_t toPort = 0);
void HandleDataMessagePayload (uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len);
void SetReceiver (const Receiver& receiver) { m_Receiver = receiver; };
void ResetReceiver () { m_Receiver = nullptr; };
void SetReceiver (const Receiver& receiver, uint16_t port) { std::lock_guard<std::mutex> lock(m_ReceiversMutex); m_ReceiversByPorts[port] = receiver; };
void ResetReceiver (uint16_t port) { std::lock_guard<std::mutex> lock(m_ReceiversMutex); m_ReceiversByPorts.erase (port); };
std::shared_ptr<DatagramSession::Info> GetInfoForRemote(const i2p::data::IdentHash & remote);
private:
// clean up after next tick
void ScheduleCleanup();
// clean up stale sessions and expire tags
void HandleCleanUp(const boost::system::error_code & ecode);
std::shared_ptr<DatagramSession> ObtainSession(const i2p::data::IdentHash & ident);
std::shared_ptr<I2NPMessage> CreateDataMessage (const uint8_t * payload, size_t len, uint16_t fromPort, uint16_t toPort);
void HandleDatagram (uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len);
/** find a receiver by port, if none by port is found try default receiever, otherwise returns nullptr */
Receiver FindReceiver(uint16_t port);
private:
i2p::client::ClientDestination * m_Owner;
boost::asio::deadline_timer m_CleanupTimer;
Receiver m_Receiver; // default
std::mutex m_SessionsMutex;
std::map<i2p::data::IdentHash, std::shared_ptr<DatagramSession> > m_Sessions;
std::mutex m_ReceiversMutex;
std::map<uint16_t, Receiver> m_ReceiversByPorts;
i2p::data::GzipInflator m_Inflator;
i2p::data::GzipDeflator m_Deflator;
};
}
}
#endif