resend

SSUData.cpp

@@ -1,5 +1,7 @@
 #include <stdlib.h>
+#include <boost/bind.hpp>
 #include "Log.h"
+#include "Timestamp.h"
 #include "SSU.h"
 #include "SSUData.h"
 
@@ -8,7 +10,7 @@ namespace i2p
 namespace ssu
 {
 	SSUData::SSUData (SSUSession& session):
-		m_Session (session)
+		m_Session (session), m_ResendTimer (session.m_Server.GetService ())
 	{
 	}
 
@@ -21,10 +23,7 @@ namespace ssu
 				delete it.second;
 			}	
 		for (auto it: m_SentMessages)
-		{
-			for (auto f: it.second.fragments)
-			delete[] f;
-		}	
+			delete it.second;
 	}
 
 	void SSUData::ProcessSentMessageAck (uint32_t msgID)
@@ -32,10 +31,10 @@ namespace ssu
 		auto it = m_SentMessages.find (msgID);
 		if (it != m_SentMessages.end ())
 		{
-			// delete all ack-ed message's fragments
-			for (auto f: it->second.fragments)
-				delete[] f;
+			delete it->second;
 			m_SentMessages.erase (it);	
+			if (m_SentMessages.empty ())
+				m_ResendTimer.cancel ();
 		}
 	}		
 
@@ -70,7 +69,7 @@ namespace ssu
 					bitfield &= 0x7F; // clear MSB
 					if (bitfield && it != m_SentMessages.end ())
 					{	
-						int numSentFragments = it->second.fragments.size ();		
+						int numSentFragments = it->second->fragments.size ();		
 						// process bits
 						uint8_t mask = 0x40;
 						for (int j = 0; j < 7; j++)
@@ -79,8 +78,8 @@ namespace ssu
 							{
 								if (fragment < numSentFragments)
 								{
-									delete[] it->second.fragments[fragment];
-									it->second.fragments[fragment] = nullptr;
+									delete it->second->fragments[fragment];
+									it->second->fragments[fragment] = nullptr;
 								}	
 							}				
 							fragment++;
@@ -237,9 +236,14 @@ namespace ssu
 			LogPrint ("SSU message ", msgID, " already sent");
 			DeleteI2NPMessage (msg);
 			return;
-		}		
-		SentMessage& sentMessage = m_SentMessages[msgID]; 
-		auto& fragments = sentMessage.fragments;
+		}	
+		if (m_SentMessages.empty ()) // schedule resend at first message only
+			ScheduleResend ();
+		SentMessage * sentMessage = new SentMessage;
+		m_SentMessages[msgID] = sentMessage; 
+		sentMessage->nextResendTime = i2p::util::GetSecondsSinceEpoch () + RESEND_INTERVAL;
+		sentMessage->numResends = 0;
+		auto& fragments = sentMessage->fragments;
 		msgID = htobe32 (msgID);	
 		size_t payloadSize = SSU_MTU - sizeof (SSUHeader) - 9; // 9  =  flag + #frg(1) + messageID(4) + frag info (3) 
 		size_t len = msg->GetLength ();
@@ -248,8 +252,9 @@ namespace ssu
 		uint32_t fragmentNum = 0;
 		while (len > 0)
 		{	
-			uint8_t * buf = new uint8_t[SSU_MTU + 18];
-			fragments.push_back (buf);
+			Fragment * fragment = new Fragment;
+			uint8_t * buf = fragment->buf;
+			fragments.push_back (fragment);
 			uint8_t	* payload = buf + sizeof (SSUHeader);
 			*payload = DATA_FLAG_WANT_REPLY; // for compatibility
 			payload++;
@@ -272,6 +277,7 @@ namespace ssu
 			size += payload - buf;
 			if (size & 0x0F) // make sure 16 bytes boundary
 				size = ((size >> 4) + 1) << 4; // (/16 + 1)*16
+			fragment->len = size; 
 			
 			// encrypt message with session key
 			m_Session.FillHeaderAndEncrypt (PAYLOAD_TYPE_DATA, buf, size);
@@ -335,6 +341,47 @@ namespace ssu
 		m_Session.Send (buf, len);
 	}	
 
+	void SSUData::ScheduleResend()
+	{		
+		m_ResendTimer.cancel ();
+		m_ResendTimer.expires_from_now (boost::posix_time::seconds(RESEND_INTERVAL));
+		m_ResendTimer.async_wait (boost::bind (&SSUData::HandleResendTimer,
+			this, boost::asio::placeholders::error));
+	}
+		
+	void SSUData::HandleResendTimer (const boost::system::error_code& ecode)
+	{
+		if (ecode != boost::asio::error::operation_aborted)
+		{
+			uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
+			for (auto it = m_SentMessages.begin (); it != m_SentMessages.end ();)
+			{
+				if (ts >= it->second->nextResendTime)
+				{	
+					bool isEmpty = true;
+					for (auto f: it->second->fragments)
+						if (f)
+						{
+							isEmpty = false;
+							m_Session.Send (f->buf, f->len); // resend
+						}
+
+					it->second->numResends++;
+					if (isEmpty || it->second->numResends >= MAX_NUM_RESENDS)
+					{
+						delete it->second;
+						it = m_SentMessages.erase (it);
+					}	
+					else
+						it++;
+				}	
+				else
+					it++;
+			}
+			if (!m_SentMessages.empty ())
+				ScheduleResend ();	
+		}	
+	}	
 }
 }
 

SSUData.h

@@ -6,6 +6,7 @@
 #include <map>
 #include <vector>
 #include <set>
+#include <boost/asio.hpp>
 #include "I2NPProtocol.h"
 
 namespace i2p
@@ -14,6 +15,8 @@ namespace ssu
 {
 
 	const size_t SSU_MTU = 1484;
+	const int RESEND_INTERVAL = 3; // in seconds
+	const int MAX_NUM_RESENDS = 5;
 	// data flags
 	const uint8_t DATA_FLAG_EXTENDED_DATA_INCLUDED = 0x02;
 	const uint8_t DATA_FLAG_WANT_REPLY = 0x04;
@@ -24,10 +27,12 @@ namespace ssu
 
 	struct Fragment
 	{
-		int fragmentNum, len;
+		int fragmentNum;
+		size_t len;
 		bool isLast;
-		uint8_t buf[SSU_MTU];
+		uint8_t buf[SSU_MTU + 18];
 
+		Fragment () = default;
 		Fragment (int n, const uint8_t * b, int l, bool last): 
 			fragmentNum (n), len (l), isLast (last) { memcpy (buf, b, len); };		
 	};	
@@ -52,9 +57,11 @@ namespace ssu
 
 	struct SentMessage
 	{
-		std::vector<uint8_t *> fragments;
+		std::vector<Fragment *> fragments;
 		uint32_t nextResendTime; // in seconds
 		int numResends;
+
+		~SentMessage () { for (auto it: fragments) { delete it; }; };
 	};	
 	
 	class SSUSession;
@@ -76,13 +83,15 @@ namespace ssu
 			void ProcessFragments (uint8_t * buf);
 			void ProcessSentMessageAck (uint32_t msgID);	
 
-		private:
-
+			void ScheduleResend ();
+			void HandleResendTimer (const boost::system::error_code& ecode);	
 			
+		private:	
 
 			SSUSession& m_Session;
 			std::map<uint32_t, IncompleteMessage *> m_IncomleteMessages;
-			std::map<uint32_t, SentMessage> m_SentMessages; // msgID -> fragments	
+			std::map<uint32_t, SentMessage *> m_SentMessages;
+			boost::asio::deadline_timer m_ResendTimer;
 	};	
 }
 }