store endpoint and send packet

libi2pd/SSU2.cpp

@@ -8,6 +8,7 @@
 
 #include <string.h>
 #include <openssl/rand.h>
+#include "Log.h"
 #include "RouterContext.h"
 #include "Transports.h"
 #include "SSU2.h"
@@ -19,7 +20,7 @@ namespace transport
 	SSU2Session::SSU2Session (SSU2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter,
 		std::shared_ptr<const i2p::data::RouterInfo::Address> addr, bool peerTest):
 		TransportSession (in_RemoteRouter, SSU2_TERMINATION_TIMEOUT),
-		m_Server (server), m_Address (addr)
+		m_Server (server), m_Address (addr), m_DestConnID (0), m_SourceConnID (0)
 	{
 		m_NoiseState.reset (new i2p::crypto::NoiseSymmetricState);
 		if (in_RemoteRouter && addr)
@@ -42,27 +43,28 @@ namespace transport
 		m_NoiseState->MixKey (sharedSecret);
 
 		Header header;
-		uint64_t headerX[6];
+		uint8_t headerX[48], payload[1200]; // TODO: correct payload size
-		uint8_t payload[1200]; // TODO: correct payload size
 		size_t payloadSize = 8;
 		// fill packet
-		RAND_bytes (header.h.connID, 8);
+		RAND_bytes ((uint8_t *)&m_DestConnID, 8);
+		header.h.connID = m_DestConnID; // dest id
 		memset (header.h.packetNum, 0, 4);
 		header.h.type = eSSU2SessionRequest;
 		header.h.flags[0] = 2; // ver
 		header.h.flags[1] = 2; // netID TODO:
 		header.h.flags[2] = 0; // flag
-		RAND_bytes ((uint8_t *)headerX, 8); // source id
+		RAND_bytes ((uint8_t *)&m_SourceConnID, 8); 
-		memset (headerX + 1, 0, 8); // token
+		memcpy (headerX, &m_SourceConnID, 8); // source id
-		memcpy (headerX + 2, m_EphemeralKeys->GetPublicKey (), 32); // X
+		memset (headerX + 8, 0, 8); // token
-		m_Server.AddSession (headerX[0], shared_from_this ());
+		memcpy (headerX + 16, m_EphemeralKeys->GetPublicKey (), 32); // X
+		m_Server.AddPendingOutgoingSession (boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port), shared_from_this ());
 		// encrypt
 		const uint8_t nonce[12] = {0};
 		i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, payloadSize + 16, true);
 		payloadSize += 16;
 		CreateHeaderMask (m_Address->i, payload + (payloadSize - 24), m_Address->i, payload + (payloadSize - 12));
 		EncryptHeader (header);
-		i2p::crypto::ChaCha20 ((uint8_t *)headerX, 48, m_Address->i, nonce, (uint8_t *)headerX);
+		i2p::crypto::ChaCha20 (headerX, 48, m_Address->i, nonce, headerX);
 		
 	}	
 
@@ -80,12 +82,39 @@ namespace transport
 		i2p::crypto::ChaCha20 (data, 8, kh2, nonce2, m_HeaderMask.buf + 8);
 	}	
 
+	SSU2Server::SSU2Server (int port):
+		m_Socket (m_Service), m_Endpoint (boost::asio::ip::udp::v6 (), port)
+	{
+	}
+
+	void SSU2Server::OpenSocket ()
+	{
+		try
+		{
+			m_Socket.open (boost::asio::ip::udp::v6());
+			m_Socket.set_option (boost::asio::socket_base::receive_buffer_size (SSU2_SOCKET_RECEIVE_BUFFER_SIZE));
+			m_Socket.set_option (boost::asio::socket_base::send_buffer_size (SSU2_SOCKET_SEND_BUFFER_SIZE));
+			m_Socket.bind (m_Endpoint);
+			LogPrint (eLogInfo, "SSU2: Start listening port ", m_Endpoint.port());
+		}
+		catch (std::exception& ex )
+		{
+			LogPrint (eLogError, "SSU2: Failed to bind to port ", m_Endpoint.port(), ": ", ex.what());
+			ThrowFatal ("Unable to start SSU2 transport at port ", m_Endpoint.port(), ": ", ex.what ());
+		}
+	}
+		
 	void SSU2Server::AddSession (uint64_t connID, std::shared_ptr<SSU2Session> session)
 	{
 		m_Sessions.emplace (connID, session);
 	}	
 
-	void SSU2Server::ProcessNextPacket (uint8_t * buf, size_t len)
+	void SSU2Server::AddPendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep, std::shared_ptr<SSU2Session> session)
+	{
+		m_PendingOutgoingSessions.emplace (ep, session);
+	}
+		
+	void SSU2Server::ProcessNextPacket (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
 	{
 		uint64_t key = 0, connID;
 		i2p::crypto::ChaCha20 ((uint8_t *)&key, 8, i2p::context.GetNTCP2IV (), buf + (len - 24), (uint8_t *)&key); // TODO: use SSU2 intro key
@@ -95,6 +124,33 @@ namespace transport
 		if (it != m_Sessions.end ())
 		{
 		}	
+		else 
+		{
+			// check pending sessions if it's SessionCreated
+			auto it1 = m_PendingOutgoingSessions.find (senderEndpoint);
+			if (it1 != m_PendingOutgoingSessions.end ())
+			{
+				m_PendingOutgoingSessions.erase (it1);
+			}
+			else
+			{
+				// assume new incoming session
+			}	
 		}	
+	}	
+
+	void SSU2Server::Send (const uint8_t * header, size_t headerLen, const uint8_t * headerX, size_t headerXLen, 
+		const uint8_t * payload, size_t payloadLen, const boost::asio::ip::udp::endpoint& to)
+	{
+		std::vector<boost::asio::const_buffer> bufs
+		{
+			boost::asio::buffer (header, headerLen),
+			boost::asio::buffer (headerX, headerXLen),
+			boost::asio::buffer (payload, payloadLen)
+		};
+		boost::system::error_code ec;
+		m_Socket.send_to (bufs, to, 0, ec);
+	}	
+	
 }
 }

libi2pd/SSU2.h

@@ -10,7 +10,9 @@
 #define SSU2_H__
 
 #include <memory>
+#include <map>
 #include <unordered_map>
+#include <boost/asio.hpp>
 #include "Crypto.h"
 #include "RouterInfo.h"
 #include "TransportSession.h"
@@ -20,6 +22,8 @@ namespace i2p
 namespace transport
 {
 	const int SSU2_TERMINATION_TIMEOUT = 330; // 5.5 minutes
+	const size_t SSU2_SOCKET_RECEIVE_BUFFER_SIZE = 0x1FFFF; // 128K
+	const size_t SSU2_SOCKET_SEND_BUFFER_SIZE = 0x1FFFF; // 128K
 	
 	enum SSU2MessageType
 	{
@@ -35,7 +39,7 @@ namespace transport
 			uint8_t buf[16];
 			struct
 			{
-				uint8_t connID[8];
+				uint64_t connID;
 				uint8_t packetNum[4];
 				uint8_t type;
 				uint8_t flags[3];
@@ -60,6 +64,7 @@ namespace transport
 			std::shared_ptr<i2p::crypto::X25519Keys> m_EphemeralKeys;
 			std::unique_ptr<i2p::crypto::NoiseSymmetricState> m_NoiseState;
 			std::shared_ptr<const i2p::data::RouterInfo::Address> m_Address;
+			uint64_t m_DestConnID, m_SourceConnID;
 			
 			union 
 			{
@@ -72,18 +77,27 @@ namespace transport
 	{
 		public:
 
-			SSU2Server (int port) {};
+			SSU2Server (int port);
 			~SSU2Server () {};
 
 			void AddSession (uint64_t connID, std::shared_ptr<SSU2Session> session);
+			void AddPendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep, std::shared_ptr<SSU2Session> session);
+
+			void Send (const uint8_t * header, size_t headerLen, const uint8_t * headerX, size_t headerXLen, 
+				const uint8_t * payload, size_t payloadLen, const boost::asio::ip::udp::endpoint& to);
 			
 		private:
 
-			void ProcessNextPacket (uint8_t * buf, size_t len);
+			void OpenSocket ();
+			void ProcessNextPacket (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint);
 			
 		private:
 
+			boost::asio::io_service m_Service;
+			boost::asio::ip::udp::socket m_Socket;
+			boost::asio::ip::udp::endpoint m_Endpoint;
 			std::unordered_map<uint64_t, std::shared_ptr<SSU2Session> > m_Sessions;
+			std::map<boost::asio::ip::udp::endpoint, std::shared_ptr<SSU2Session> > m_PendingOutgoingSessions;
 	};	
 }
 }