From 1441c1371bc585d729188c6cfa96ef9997ecbe40 Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Thu, 18 Sep 2014 14:37:29 -0400
Subject: [PATCH] adjust MTU for incoming SSU sessions

---
 SSU.cpp     |  1 +
 SSUData.cpp | 51 +++++++++++++++++++++++++++++++--------------------
 SSUData.h   |  6 ++++++
 3 files changed, 38 insertions(+), 20 deletions(-)

diff --git a/SSU.cpp b/SSU.cpp
index d5fbdca6..e6ac08ec 100644
--- a/SSU.cpp
+++ b/SSU.cpp
@@ -236,6 +236,7 @@ namespace ssu
 			i2p::data::Identity ident;
 			ident.FromBuffer (payload, identitySize);
 			m_RemoteIdent = ident.Hash ();
+			m_Data.UpdatePacketSize (m_RemoteIdent);
 		}
 		else
 			LogPrint ("SSU unexpected identity size ", identitySize);
diff --git a/SSUData.cpp b/SSUData.cpp
index 9cfecd7e..62ffba61 100644
--- a/SSUData.cpp
+++ b/SSUData.cpp
@@ -2,6 +2,7 @@
 #include <boost/bind.hpp>
 #include "Log.h"
 #include "Timestamp.h"
+#include "NetDb.h"
 #include "SSU.h"
 #include "SSUData.h"
 
@@ -15,26 +16,7 @@ namespace ssu
 		m_PacketSize = SSU_MAX_PACKET_SIZE;
 		auto remoteRouter = session.GetRemoteRouter ();
 		if (remoteRouter)
-		{
-			auto ssuAddress = remoteRouter->GetSSUAddress ();
-			if (ssuAddress && ssuAddress->mtu)
-			{
-				m_PacketSize = ssuAddress->mtu - IPV4_HEADER_SIZE - UDP_HEADER_SIZE;
-				if (m_PacketSize > 0)
-				{
-					// make sure packet size multiple of 16
-					m_PacketSize >>= 4;
-					m_PacketSize <<= 4;
-					if (m_PacketSize > (int)SSU_MAX_PACKET_SIZE) m_PacketSize = SSU_MAX_PACKET_SIZE;
-					LogPrint ("MTU=", ssuAddress->mtu, " packet size=", m_PacketSize); 
-				}
-				else
-				{	
-					LogPrint ("Unexpected MTU ", ssuAddress->mtu);
-					m_PacketSize = SSU_MAX_PACKET_SIZE;
-				}	
-			}	
-		}	
+			AdjustPacketSize (*remoteRouter);
 	}
 
 	SSUData::~SSUData ()
@@ -49,6 +31,35 @@ namespace ssu
 			delete it.second;
 	}
 
+	void SSUData::AdjustPacketSize (const i2p::data::RouterInfo& remoteRouter)
+	{
+		auto ssuAddress = remoteRouter.GetSSUAddress ();
+		if (ssuAddress && ssuAddress->mtu)
+		{
+			m_PacketSize = ssuAddress->mtu - IPV4_HEADER_SIZE - UDP_HEADER_SIZE;
+			if (m_PacketSize > 0)
+			{
+				// make sure packet size multiple of 16
+				m_PacketSize >>= 4;
+				m_PacketSize <<= 4;
+				if (m_PacketSize > (int)SSU_MAX_PACKET_SIZE) m_PacketSize = SSU_MAX_PACKET_SIZE;
+				LogPrint ("MTU=", ssuAddress->mtu, " packet size=", m_PacketSize); 
+			}
+			else
+			{	
+				LogPrint ("Unexpected MTU ", ssuAddress->mtu);
+				m_PacketSize = SSU_MAX_PACKET_SIZE;
+			}	
+		}		
+	}
+
+	void SSUData::UpdatePacketSize (const i2p::data::IdentHash& remoteIdent)
+	{
+ 		auto routerInfo = i2p::data::netdb.FindRouter (remoteIdent);
+		if (routerInfo)
+			AdjustPacketSize (*routerInfo);
+	}
+
 	void SSUData::ProcessSentMessageAck (uint32_t msgID)
 	{
 		auto it = m_SentMessages.find (msgID);
diff --git a/SSUData.h b/SSUData.h
index 9d29757e..afa36f8d 100644
--- a/SSUData.h
+++ b/SSUData.h
@@ -8,6 +8,8 @@
 #include <set>
 #include <boost/asio.hpp>
 #include "I2NPProtocol.h"
+#include "Identity.h"
+#include "RouterInfo.h"
 
 namespace i2p
 {
@@ -78,6 +80,8 @@ namespace ssu
 			void ProcessMessage (uint8_t * buf, size_t len);
 			void Send (i2p::I2NPMessage * msg);
 
+			void UpdatePacketSize (const i2p::data::IdentHash& remoteIdent);
+
 		private:
 
 			void SendMsgAck (uint32_t msgID);
@@ -89,6 +93,8 @@ namespace ssu
 			void ScheduleResend ();
 			void HandleResendTimer (const boost::system::error_code& ecode);	
 			
+			void AdjustPacketSize (const i2p::data::RouterInfo& remoteRouter);	
+			
 		private:	
 
 			SSUSession& m_Session;