diff --git a/SSU.cpp b/SSU.cpp
index 4a9892ab..314a62da 100644
--- a/SSU.cpp
+++ b/SSU.cpp
@@ -47,6 +47,11 @@ namespace ssu
 	{
 		switch (m_State)
 		{
+			case eSessionStateEstablised:
+				// most common case
+				ProcessMessage (buf, len);
+			break;
+			// establishing
 			case eSessionStateUnknown:
 				// session request
 				ProcessSessionRequest (buf, len, senderEndpoint);
@@ -64,6 +69,34 @@ namespace ssu
 		}
 	}
 
+	void SSUSession::ProcessMessage (uint8_t * buf, size_t len)
+	{
+		if (Validate (buf, len, m_MacKey))
+		{
+			Decrypt (buf, len, m_SessionKey);
+			SSUHeader * header = (SSUHeader *)buf;
+			uint8_t payloadType = header->flag >> 4;
+			switch (payloadType)
+			{
+				case PAYLOAD_TYPE_DATA:
+					LogPrint ("SSU data received");
+					ProcessData (buf + sizeof (SSUHeader), len - sizeof (SSUHeader));
+				break;
+				case PAYLOAD_TYPE_TEST:
+					LogPrint ("SSU test received");
+				break;
+				case PAYLOAD_TYPE_SESSION_DESTROY:
+					LogPrint ("SSU session destroy received");
+				break;	
+				default:
+					LogPrint ("Unexpected SSU payload type ", (int)payloadType);
+			}
+		}
+		// TODO: try intro key as well
+		else
+			LogPrint ("MAC verifcation failed");	
+	}
+
 	void SSUSession::ProcessSessionRequest (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
 	{
 		LogPrint ("Process session request");
@@ -98,6 +131,7 @@ namespace ssu
 			LogPrint ("Our external address is ", ourIP.to_string (), ":", ourPort);
 			uint32_t relayTag = be32toh (*(uint32_t *)(buf + sizeof (SSUHeader) + 263));
 			SendSessionConfirmed (buf + sizeof (SSUHeader), ourAddress, relayTag);
+			m_State = eSessionStateEstablised;
 		}
 	}	
 
@@ -113,6 +147,7 @@ namespace ssu
 				m_State = eSessionStateConfirmedReceived;
 				LogPrint ("Session confirmed received");	
 				// TODO:	
+				m_State = eSessionStateEstablised;
 			}
 			else
 				LogPrint ("Unexpected payload type ", (int)(header->flag >> 4));	
@@ -327,6 +362,31 @@ namespace ssu
 		// TODO:
 	}	
 
+	void SSUSession::ProcessData (uint8_t * buf, size_t len)
+	{
+		//uint8_t * start = buf;
+		uint8_t flag = *buf;
+		buf++;
+		LogPrint ("Process SSU data flags=", (int)flag);
+		uint8_t numFragments = *buf; // number of fragments
+		buf++;
+		for (int i = 0; i < numFragments; i++)
+		{	
+			uint32_t msgID = be32toh (*(uint32_t *)buf); // message ID
+			buf += 4;
+			uint8_t frag[4];
+			frag[0] = 0;
+			memcpy (frag + 1, buf, 3);
+			buf += 3;
+			uint32_t fragmentInfo = be32toh (*(uint32_t *)frag); // fragment info
+			uint16_t fragmentSize = fragmentInfo & 0x1FFF; // bits 0 - 13
+			bool isLast = fragmentInfo & 0x010000; // bit 16	
+			uint8_t fragmentNum = fragmentInfo >> 17; // bits 23 - 17
+			LogPrint ("SSU data fragment ", (int)fragmentNum, " of message ", msgID, " size=", (int)fragmentSize, isLast ? " last" : " non-last"); 
+			buf += fragmentSize;
+		}	
+	}
+
 	SSUServer::SSUServer (boost::asio::io_service& service, int port):
 		m_Endpoint (boost::asio::ip::udp::v4 (), port), m_Socket (service, m_Endpoint)
 	{
diff --git a/SSU.h b/SSU.h
index c33b3f83..aee160ae 100644
--- a/SSU.h
+++ b/SSU.h
@@ -65,12 +65,14 @@ namespace ssu
 
 			void CreateAESandMacKey (uint8_t * pubKey, uint8_t * aesKey, uint8_t * macKey); 
 
+			void ProcessMessage (uint8_t * buf, size_t len); // call for established session
 			void ProcessSessionRequest (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint);
 			void SendSessionRequest ();
 			void ProcessSessionCreated (uint8_t * buf, size_t len);
 			void SendSessionCreated (const uint8_t * x);
 			void ProcessSessionConfirmed (uint8_t * buf, size_t len);
 			void SendSessionConfirmed (const uint8_t * y, const uint8_t * ourAddress, uint32_t relayTag);
+			void ProcessData (uint8_t * buf, size_t len);	
 
 			bool ProcessIntroKeyEncryptedMessage (uint8_t expectedPayloadType, i2p::data::RouterInfo& r, uint8_t * buf, size_t len);
 			void FillHeaderAndEncrypt (uint8_t payloadType, uint8_t * buf, size_t len, uint8_t * aesKey, uint8_t * iv, uint8_t * macKey);
diff --git a/i2p.cpp b/i2p.cpp
index 24341fe7..355c2003 100644
--- a/i2p.cpp
+++ b/i2p.cpp
@@ -29,23 +29,29 @@
 int running = 1;
 
 #ifndef _WIN32
-void handle_sighup(int n)
+void handle_signal(int sig)
 {
-  if (i2p::util::config::GetArg("daemon", 0) == 1)
+  switch (sig)
   {
-    static bool first=true;
-    if (first)
-    {
-      first=false;
-      return;
-    }
+    case SIGHUP:
+      if (i2p::util::config::GetArg("daemon", 0) == 1)
+      {
+        static bool first=true;
+        if (first)
+        {
+          first=false;
+          return;
+        }
+      }
+      LogPrint("Reloading config.");
+      i2p::util::filesystem::ReadConfigFile(i2p::util::config::mapArgs, i2p::util::config::mapMultiArgs);
+    break;
+    case SIGABRT:
+    case SIGTERM:
+    case SIGINT:
+      running = 0; // Exit loop
+    break;
   }
-  LogPrint("Reloading config.");
-  i2p::util::filesystem::ReadConfigFile(i2p::util::config::mapArgs, i2p::util::config::mapMultiArgs);
-}
-void handle_shutdown(int sig)
-{
-  running = 0; // Exit loop
 }
 #endif
 
@@ -66,15 +72,6 @@ int main( int argc, char* argv[] )
   i2p::util::filesystem::ReadConfigFile(i2p::util::config::mapArgs, i2p::util::config::mapMultiArgs);
 
 #ifndef _WIN32
-  struct sigaction sa;
-  sa.sa_handler = handle_sighup;
-  sigemptyset(&sa.sa_mask);
-  sa.sa_flags = SA_RESTART;
-  if (sigaction(SIGHUP,&sa,0) == -1)
-  {
-    LogPrint("Failed to install SIGHUP handler.");
-  }
-
   if (i2p::util::config::GetArg("-daemon", 0) == 1)
   {
     pid_t pid;
@@ -96,12 +93,36 @@ int main( int argc, char* argv[] )
       LogPrint("Error, could not create process group.");
       return -1;
     }
+    chdir(i2p::util::filesystem::GetDataDir().string().c_str());
   }
 
-  // Handle shutdown
-  signal(SIGABRT, &handle_shutdown);
-  signal(SIGTERM, &handle_shutdown);
-  signal(SIGINT, &handle_shutdown);
+  // Pidfile
+  std::string pidfile = i2p::util::filesystem::GetDataDir().string();
+  pidfile.append("/i2pd.pid");
+  int pidFilehandle = open(pidfile.c_str(), O_RDWR|O_CREAT, 0600);
+  if (pidFilehandle == -1 )
+  {
+    LogPrint("Error, could not create pid file (", pidfile, ")\nIs an instance already running?");
+    return -1;
+  }
+  if (lockf(pidFilehandle,F_TLOCK,0) == -1)
+  {
+    LogPrint("Error, could not lock pid file (", pidfile, ")\nIs an instance already running?");
+    return -1;
+  }
+  char pid[10];
+  sprintf(pid,"%d\n",getpid());
+  write(pidFilehandle, pid, strlen(pid));
+
+  // Signal handler
+  struct sigaction sa;
+  sa.sa_handler = handle_signal;
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = SA_RESTART;
+  sigaction(SIGHUP,&sa,0);
+  sigaction(SIGABRT,&sa,0);
+  sigaction(SIGTERM,&sa,0);
+  sigaction(SIGINT,&sa,0);
 #endif
 
   if (i2p::util::config::GetArg("-log", 0) == 1)
@@ -123,9 +144,9 @@ int main( int argc, char* argv[] )
 
   i2p::util::HTTPServer httpServer (i2p::util::config::GetArg("-httpport", 7070));
 
-  httpServer.Start ();	
+  httpServer.Start ();
   i2p::data::netdb.Start ();
-  i2p::transports.Start ();	
+  i2p::transports.Start ();
   i2p::tunnel::tunnels.Start ();
 
   while (running)
@@ -135,14 +156,18 @@ int main( int argc, char* argv[] )
   }
   LogPrint("Shutdown started.");
 
-  i2p::tunnel::tunnels.Stop ();	
-  i2p::transports.Stop ();	
-  i2p::data::netdb.Stop ();	
+  i2p::tunnel::tunnels.Stop ();
+  i2p::transports.Stop ();
+  i2p::data::netdb.Stop ();
   httpServer.Stop ();
 
   if (i2p::util::config::GetArg("-log", 0) == 1)
   {
     fclose (stdout);
   }
+#ifndef _WIN32
+  close(pidFilehandle);
+  unlink(pidfile.c_str());
+#endif
   return 0;
 }