From fde301deaf7277109694b50bc9c901d7d667f049 Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Thu, 5 Sep 2024 19:24:23 -0400
Subject: [PATCH] check for duplicated routers in NTCP2. Insert router into
 netdb right a way

---
 libi2pd/I2NPProtocol.h |  1 -
 libi2pd/NTCP2.cpp      | 39 ++++++++++++++++++++++++++++++++-------
 libi2pd/NetDb.cpp      |  4 ----
 3 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/libi2pd/I2NPProtocol.h b/libi2pd/I2NPProtocol.h
index 1acd4242..4e26fc94 100644
--- a/libi2pd/I2NPProtocol.h
+++ b/libi2pd/I2NPProtocol.h
@@ -107,7 +107,6 @@ namespace i2p
 
 	enum I2NPMessageType
 	{
-		eI2NPDummyMsg = 0,
 		eI2NPDatabaseStore = 1,
 		eI2NPDatabaseLookup = 2,
 		eI2NPDatabaseSearchReply = 3,
diff --git a/libi2pd/NTCP2.cpp b/libi2pd/NTCP2.cpp
index 7f0f2189..de14d3b0 100644
--- a/libi2pd/NTCP2.cpp
+++ b/libi2pd/NTCP2.cpp
@@ -724,8 +724,24 @@ namespace transport
 						SendTerminationAndTerminate (eNTCP2Message3Error);
 						return;
 					}	
-					auto addr = m_RemoteEndpoint.address ().is_v4 () ? ri.GetNTCP2V4Address () :
-						(i2p::util::net::IsYggdrasilAddress (m_RemoteEndpoint.address ()) ? ri.GetYggdrasilAddress () : ri.GetNTCP2V6Address ());
+					// update RouterInfo in netdb
+					auto ri1 = i2p::data::netdb.AddRouterInfo (ri.GetBuffer (), ri.GetBufferLen ()); // ri1 points to one from netdb now
+					if (!ri1)
+					{
+						LogPrint (eLogError, "NTCP2: Couldn't update RouterInfo from SessionConfirmed in netdb");
+						return;
+					}
+					std::shared_ptr<i2p::data::RouterProfile> profile; // not null if older 
+					if (ri.GetTimestamp () + i2p::data::NETDB_EXPIRATION_TIMEOUT_THRESHOLD*1000LL < ri1->GetTimestamp ())
+					{	
+						// received RouterInfo is older than one in netdb
+						profile = i2p::data::GetRouterProfile (ri1->GetIdentHash ()); // retrieve profile	
+						if (profile && profile->IsDuplicated ())
+							return;
+					}
+					
+					auto addr = m_RemoteEndpoint.address ().is_v4 () ? ri1->GetNTCP2V4Address () :
+						(i2p::util::net::IsYggdrasilAddress (m_RemoteEndpoint.address ()) ? ri1->GetYggdrasilAddress () : ri1->GetNTCP2V6Address ());
 					if (!addr || memcmp (m_Establisher->m_RemoteStaticKey, addr->s, 32))
 					{
 						LogPrint (eLogError, "NTCP2: Wrong static key in SessionConfirmed");
@@ -737,16 +753,17 @@ namespace transport
 					     memcmp (m_RemoteEndpoint.address ().to_v6 ().to_bytes ().data () + 1, addr->host.to_v6 ().to_bytes ().data () + 1, 7) : // from the same yggdrasil subnet
 					     memcmp (m_RemoteEndpoint.address ().to_v6 ().to_bytes ().data (), addr->host.to_v6 ().to_bytes ().data (), 8)))) // temporary address
 					{
-						LogPrint (eLogError, "NTCP2: Host mismatch between published address ", addr->host, " and actual endpoint ", m_RemoteEndpoint.address ());
+						if (profile) // older router?
+							profile->Duplicated (); // mark router as duplicated in profile
+						else
+							LogPrint (eLogError, "NTCP2: Host mismatch between published address ", addr->host, " and actual endpoint ", m_RemoteEndpoint.address ());
 						Terminate ();
 						return;
 					}
-					i2p::data::netdb.PostI2NPMsg (CreateI2NPMessage (eI2NPDummyMsg, buf.data () + 3, size)); // TODO: should insert ri and not parse it twice
 					// TODO: process options
 
 					// ready to communicate
-					auto existing = i2p::data::netdb.FindRouter (ri.GetRouterIdentity ()->GetIdentHash ()); // check if exists already
-					SetRemoteIdentity (existing ? existing->GetRouterIdentity () : ri.GetRouterIdentity ());
+					SetRemoteIdentity (ri1->GetRouterIdentity ());
 					if (m_Server.AddNTCP2Session (shared_from_this (), true))
 					{
 						Established ();
@@ -939,7 +956,15 @@ namespace transport
 				case eNTCP2BlkRouterInfo:
 				{
 					LogPrint (eLogDebug, "NTCP2: RouterInfo flag=", (int)frame[offset]);
-					i2p::data::netdb.PostI2NPMsg (CreateI2NPMessage (eI2NPDummyMsg, frame + offset, size));
+					i2p::data::RouterInfo ri (frame + offset + 1, size - 1);	
+					auto newRi = i2p::data::netdb.AddRouterInfo (ri.GetBuffer (), ri.GetBufferLen ());
+					if (newRi)
+					{
+						auto remoteIdentity = GetRemoteIdentity ();
+						if (remoteIdentity && remoteIdentity->GetIdentHash () == newRi->GetIdentHash ())
+							// peer's RouterInfo update
+							SetRemoteIdentity (newRi->GetIdentity ());
+					}	
 					break;
 				}
 				case eNTCP2BlkI2NPMessage:
diff --git a/libi2pd/NetDb.cpp b/libi2pd/NetDb.cpp
index b222ac88..ccc43d7a 100644
--- a/libi2pd/NetDb.cpp
+++ b/libi2pd/NetDb.cpp
@@ -141,10 +141,6 @@ namespace data
 							case eI2NPDatabaseLookup:
 								HandleDatabaseLookupMsg (msg);
 							break;
-							case eI2NPDummyMsg:
-								// plain RouterInfo from NTCP2 with flags for now
-								HandleNTCP2RouterInfoMsg (msg);
-							break;
 							default: // WTF?
 								LogPrint (eLogError, "NetDb: Unexpected message type ", (int) msg->GetTypeID ());
 								//i2p::HandleI2NPMessage (msg);