From d50cf0ad83dfea3b00b27dc1789ff6032f985f3f Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Fri, 3 Mar 2023 20:21:56 -0500
Subject: [PATCH] recognize congestion caps

---
 libi2pd/NetDb.cpp      |  2 +-
 libi2pd/RouterInfo.cpp | 38 +++++++++++++++++++++++++++++++++++---
 libi2pd/RouterInfo.h   | 20 +++++++++++++++++++-
 3 files changed, 55 insertions(+), 5 deletions(-)

diff --git a/libi2pd/NetDb.cpp b/libi2pd/NetDb.cpp
index 18f948ac..5dfb7889 100644
--- a/libi2pd/NetDb.cpp
+++ b/libi2pd/NetDb.cpp
@@ -1210,7 +1210,7 @@ namespace data
 						router->IsReachableFrom (*compatibleWith)) &&
 					(router->GetCaps () & RouterInfo::eHighBandwidth) &&
 					router->GetVersion () >= NETDB_MIN_HIGHBANDWIDTH_VERSION &&
-					router->IsECIES ();
+					router->IsECIES () && !router->IsHighCongestion ();
 			});
 	}
 
diff --git a/libi2pd/RouterInfo.cpp b/libi2pd/RouterInfo.cpp
index 8117b9fb..e6197061 100644
--- a/libi2pd/RouterInfo.cpp
+++ b/libi2pd/RouterInfo.cpp
@@ -43,7 +43,7 @@ namespace data
 	RouterInfo::RouterInfo (const std::string& fullPath):
 		m_FamilyID (0), m_IsUpdated (false), m_IsUnreachable (false),
 		m_SupportedTransports (0),m_ReachableTransports (0),
-		m_Caps (0), m_Version (0)
+		m_Caps (0), m_Version (0), m_Congestion (eLowCongestion)
 	{
 		m_Addresses = boost::make_shared<Addresses>(); // create empty list
 		m_Buffer = NewBuffer (); // always RouterInfo's
@@ -53,7 +53,7 @@ namespace data
 	RouterInfo::RouterInfo (std::shared_ptr<Buffer>&& buf, size_t len):
 		m_FamilyID (0), m_IsUpdated (true), m_IsUnreachable (false),
 		m_SupportedTransports (0), m_ReachableTransports (0),
-		m_Caps (0), m_Version (0)
+		m_Caps (0), m_Version (0), m_Congestion (eLowCongestion)
 	{
 		if (len <= MAX_RI_BUFFER_SIZE)
 		{
@@ -202,7 +202,7 @@ namespace data
 	void RouterInfo::ReadFromStream (std::istream& s)
 	{
 		if (!s) return;
-		m_Caps = 0;
+		m_Caps = 0; m_Congestion = eLowCongestion;
 		s.read ((char *)&m_Timestamp, sizeof (m_Timestamp));
 		m_Timestamp = be64toh (m_Timestamp);
 		// read addresses
@@ -535,6 +535,15 @@ namespace data
 				case CAPS_FLAG_UNREACHABLE:
 					m_Caps |= Caps::eUnreachable;
 				break;
+				case CAPS_FLAG_MEDIUM_COGNESTION:
+					m_Congestion = eMediumCongestion;
+				break;
+				case CAPS_FLAG_HIGH_COGNESTION:
+					m_Congestion = eHighCongestion;
+				break;
+				case CAPS_FLAG_REJECT_ALL_COGNESTION:
+					m_Congestion = eRejectAll;
+				break;	
 				default: ;
 			}
 			cap++;
@@ -1057,6 +1066,15 @@ namespace data
 		m_Timestamp = i2p::util::GetMillisecondsSinceEpoch ();
 	}
 
+	bool RouterInfo::IsHighCongestion () const
+	{
+		if (m_Congestion == eLowCongestion || m_Congestion == eMediumCongestion) return false;
+		if (m_Congestion == eRejectAll) return true;
+		if (m_Congestion == eHighCongestion)
+			return 	(i2p::util::GetMillisecondsSinceEpoch () < m_Timestamp + HIGH_COGNESION_INTERVAL*1000LL) ? true : false;
+		return false;
+	}	
+		
 	void LocalRouterInfo::CreateBuffer (const PrivateKeys& privateKeys)
 	{
 		RefreshTimestamp ();
@@ -1108,6 +1126,20 @@ namespace data
 		if (c & eReachable) caps += CAPS_FLAG_REACHABLE; // reachable
 		if (c & eUnreachable) caps += CAPS_FLAG_UNREACHABLE; // unreachable
 
+		switch (GetCongestion ())
+		{
+			case eMediumCongestion:
+				caps += CAPS_FLAG_MEDIUM_COGNESTION;
+			break;	
+			case eHighCongestion:
+				caps += CAPS_FLAG_HIGH_COGNESTION;
+			break;		
+			case eRejectAll:
+				caps += CAPS_FLAG_REJECT_ALL_COGNESTION;
+			break;	
+			default: ;	
+		};	
+		
 		SetProperty ("caps", caps);
 	}
 
diff --git a/libi2pd/RouterInfo.h b/libi2pd/RouterInfo.h
index ffab8e10..e0ca53e5 100644
--- a/libi2pd/RouterInfo.h
+++ b/libi2pd/RouterInfo.h
@@ -44,7 +44,11 @@ namespace data
 	const char CAPS_FLAG_HIGH_BANDWIDTH3  = 'O'; /* 128-256 KBps */
 	const char CAPS_FLAG_EXTRA_BANDWIDTH1 = 'P'; /* 256-2000 KBps */
 	const char CAPS_FLAG_EXTRA_BANDWIDTH2 = 'X'; /*   > 2000 KBps */
-
+	// congesion flags
+	const char CAPS_FLAG_MEDIUM_COGNESTION = 'D';
+	const char CAPS_FLAG_HIGH_COGNESTION = 'E';
+	const char CAPS_FLAG_REJECT_ALL_COGNESTION = 'G';
+	
 	const char CAPS_FLAG_V4 = '4';
 	const char CAPS_FLAG_V6 = '6';
 	const char CAPS_FLAG_SSU2_TESTING = 'B';
@@ -56,6 +60,8 @@ namespace data
 	const uint8_t COST_SSU2_NON_PUBLISHED = 15;
 
 	const size_t MAX_RI_BUFFER_SIZE = 3072; // if RouterInfo exceeds 3K we consider it as malformed, might extend later
+	const int HIGH_COGNESION_INTERVAL = 15*60; // in seconds, 15 minutes
+		
 	class RouterInfo: public RoutingDestination
 	{
 		public:
@@ -93,6 +99,14 @@ namespace data
 				eUnreachable = 0x20
 			};
 
+			enum Congestion
+			{
+				eLowCongestion = 0,
+				eMediumCongestion,
+				eHighCongestion,
+				eRejectAll
+			};
+		
 			enum AddressCaps
 			{
 				eV4 = 0x01,
@@ -234,10 +248,13 @@ namespace data
 			bool IsEligibleFloodfill () const;
 			bool IsSSU2PeerTesting (bool v4) const;
 			bool IsSSU2Introducer (bool v4) const;
+			bool IsHighCongestion () const;
 
 			uint8_t GetCaps () const { return m_Caps; };
 			void SetCaps (uint8_t caps) { m_Caps = caps; };
 
+			Congestion GetCongestion () const { return m_Congestion; };
+		
 			void SetUnreachable (bool unreachable) { m_IsUnreachable = unreachable; };
 			bool IsUnreachable () const { return m_IsUnreachable; };
 
@@ -302,6 +319,7 @@ namespace data
 			CompatibleTransports m_SupportedTransports, m_ReachableTransports;
 			uint8_t m_Caps;
 			int m_Version;
+			Congestion m_Congestion;
 			mutable std::shared_ptr<RouterProfile> m_Profile;
 	};