try adding garlic and session tags to datagram destination

Datagram.cpp

@@ -12,12 +12,17 @@ namespace i2p
 namespace datagram
 {
 	DatagramDestination::DatagramDestination (std::shared_ptr<i2p::client::ClientDestination> owner): 
-		m_Owner (owner.get()), m_Receiver (nullptr)
+		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)
@@ -42,44 +47,10 @@ namespace datagram
 			owner->Sign (buf1, len, signature);
 
 		auto msg = CreateDataMessage (buf, len + headerLen, fromPort, toPort);
-		auto remote = owner->FindLeaseSet (ident);
-		if (remote)
-			owner->GetService ().post (std::bind (&DatagramDestination::SendMsg, this, msg, remote));
-		else
-      owner->RequestDestination (ident, std::bind (&DatagramDestination::HandleLeaseSetRequestComplete, this, std::placeholders::_1, msg));
+    auto session = ObtainSession(ident);
+    session->SendMsg(msg);
   }
 
-	void DatagramDestination::HandleLeaseSetRequestComplete (std::shared_ptr<i2p::data::LeaseSet> remote, std::shared_ptr<I2NPMessage> msg)
-	{
-		if (remote)
-			SendMsg (msg, remote);
-	}	
-		
-	void DatagramDestination::SendMsg (std::shared_ptr<I2NPMessage> msg, std::shared_ptr<const i2p::data::LeaseSet> remote)
-	{
-		auto outboundTunnel = m_Owner->GetTunnelPool ()->GetNextOutboundTunnel ();
-		auto leases = remote->GetNonExpiredLeases ();
-		if (!leases.empty () && outboundTunnel)
-		{
-			std::vector<i2p::tunnel::TunnelMessageBlock> msgs;			
-			uint32_t i = rand () % leases.size ();
-			auto garlic = m_Owner->WrapMessage (remote, msg, true);
-			msgs.push_back (i2p::tunnel::TunnelMessageBlock 
-				{ 
-					i2p::tunnel::eDeliveryTypeTunnel,
-					leases[i]->tunnelGateway, leases[i]->tunnelID,
-					garlic
-				});
-			outboundTunnel->SendTunnelDataMsg (msgs);
-		}
-		else
-		{
-			if (outboundTunnel)
-				LogPrint (eLogWarning, "Failed to send datagram. All leases expired");
-			else
-				LogPrint (eLogWarning, "Failed to send datagram. No outbound tunnels");
-		}	
-	}
 
 	void DatagramDestination::HandleDatagram (uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len)
 	{
@@ -140,6 +111,222 @@ namespace datagram
 			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);
+    }
+  }
+  
+  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)
+      {
+        // 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);
+    }
+  }
 }
 }
 

Datagram.h

@@ -9,6 +9,7 @@
 #include "Identity.h"
 #include "LeaseSet.h"
 #include "I2NPProtocol.h"
+#include "Garlic.h"
 
 namespace i2p
 {
@@ -18,6 +19,51 @@ namespace client
 }
 namespace datagram
 {
+
+  // seconds interval for cleanup timer
+  const int DATAGRAM_SESSION_CLEANUP_INTERVAL = 30;
+  // milliseconds for max session idle time (10 minutes)
+  const uint64_t DATAGRAM_SESSION_MAX_IDLE = 3600 * 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; }
+  private:
+
+    /** 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;
+  };
+  
 	const size_t MAX_DATAGRAM_SIZE = 32768;  
 	class DatagramDestination
 	{
@@ -38,17 +84,24 @@ namespace datagram
 			void ResetReceiver (uint16_t port) { m_ReceiversByPorts.erase (port); };
     
 		private:
+      // clean up after next tick
+      void ScheduleCleanup();
+    
+      // clean up stale sessions and expire tags
+      void HandleCleanUp(const boost::system::error_code & ecode);
       
-			void HandleLeaseSetRequestComplete (std::shared_ptr<i2p::data::LeaseSet> leaseSet, std::shared_ptr<I2NPMessage> msg);
+      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 SendMsg (std::shared_ptr<I2NPMessage> msg, std::shared_ptr<const i2p::data::LeaseSet> remote);
+
 			void HandleDatagram (uint16_t fromPort, uint16_t toPort, const uint8_t * buf, size_t len);
 
 		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::map<uint16_t, Receiver> m_ReceiversByPorts;
 
 			i2p::data::GzipInflator m_Inflator;

Destination.cpp

@@ -701,6 +701,8 @@ namespace client
 			m_StreamingDestination = nullptr;
 			for (auto& it: m_StreamingDestinationsByPorts)
 				it.second->Stop ();
+      if(m_DatagramDestination)
+        delete m_DatagramDestination;
       m_DatagramDestination = nullptr;
   		return true;
 		}

LeaseSet.cpp

@@ -171,6 +171,11 @@ namespace data
 	}
 
   const std::vector<std::shared_ptr<const Lease> > LeaseSet::GetNonExpiredLeases (bool withThreshold) const
+  {
+    return GetNonExpiredLeasesExcluding( [] (const Lease & l) -> bool { return false; }, withThreshold);
+  }
+  
+	const std::vector<std::shared_ptr<const Lease> > LeaseSet::GetNonExpiredLeasesExcluding (LeaseInspectFunc exclude, bool withThreshold) const
 	{
 		auto ts = i2p::util::GetMillisecondsSinceEpoch ();
 		std::vector<std::shared_ptr<const Lease> > leases;
@@ -181,7 +186,7 @@ namespace data
 				endDate += LEASE_ENDDATE_THRESHOLD;
 			else
 				endDate -= LEASE_ENDDATE_THRESHOLD;
-			if (ts < endDate)
+			if (ts < endDate && !exclude(*it))
 				leases.push_back (it);
 		}	
 		return leases;	

LeaseSet.h

@@ -38,6 +38,8 @@ namespace data
 		};
 	};	
 
+  typedef std::function<bool(const Lease & l)> LeaseInspectFunc;
+  
 	const size_t MAX_LS_BUFFER_SIZE = 3072;
 	const size_t LEASE_SIZE = 44; // 32 + 4 + 8
 	const uint8_t MAX_NUM_LEASES = 16;		
@@ -56,6 +58,7 @@ namespace data
 			size_t GetBufferLen () const { return m_BufferLen; };	
 			bool IsValid () const { return m_IsValid; };
 			const std::vector<std::shared_ptr<const Lease> > GetNonExpiredLeases (bool withThreshold = true) const;
+      const std::vector<std::shared_ptr<const Lease> > GetNonExpiredLeasesExcluding (LeaseInspectFunc exclude, bool withThreshold = true)  const;
 			bool HasExpiredLeases () const;
 			bool IsExpired () const;
 			bool IsEmpty () const { return m_Leases.empty (); };

TunnelPool.h

@@ -45,7 +45,6 @@ namespace tunnel
 			std::shared_ptr<OutboundTunnel> GetNextOutboundTunnel (std::shared_ptr<OutboundTunnel> excluded = nullptr) const;
 			std::shared_ptr<InboundTunnel> GetNextInboundTunnel (std::shared_ptr<InboundTunnel> excluded = nullptr) const;		
 			std::shared_ptr<OutboundTunnel> GetNewOutboundTunnel (std::shared_ptr<OutboundTunnel> old) const;
-
 			void TestTunnels ();
 			void ProcessGarlicMessage (std::shared_ptr<I2NPMessage> msg);
 			void ProcessDeliveryStatus (std::shared_ptr<I2NPMessage> msg);