Split IF-TNCCS 2.0 protocol processing into separate TNC client and server handlers

9 files changed, 1746 insertions, 799 deletions

diff --git a/src/libtnccs/plugins/tnccs_20/Makefile.am b/src/libtnccs/plugins/tnccs_20/Makefile.am
index 2aefecd26..3cb1d800a 100644
--- a/src/libtnccs/plugins/tnccs_20/Makefile.am
+++ b/src/libtnccs/plugins/tnccs_20/Makefile.am
@@ -18,6 +18,8 @@ endif
 
 libstrongswan_tnccs_20_la_SOURCES = \
 	tnccs_20_plugin.h tnccs_20_plugin.c tnccs_20.h tnccs_20.c \
+	tnccs_20_handler.h \
+	tnccs_20_server.h tnccs_20_server.c tnccs_20_client.h tnccs_20_client.c \
 	batch/pb_tnc_batch.h batch/pb_tnc_batch.c \
 	messages/pb_tnc_msg.h messages/pb_tnc_msg.c \
 	messages/ietf/pb_experimental_msg.h messages/ietf/pb_experimental_msg.c \
diff --git a/src/libtnccs/plugins/tnccs_20/batch/pb_tnc_batch.c b/src/libtnccs/plugins/tnccs_20/batch/pb_tnc_batch.c
index 228c08255..57e4ec0e4 100644
--- a/src/libtnccs/plugins/tnccs_20/batch/pb_tnc_batch.c
+++ b/src/libtnccs/plugins/tnccs_20/batch/pb_tnc_batch.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2010 Sansar Choinyanbuu
- * Copyright (C) 2010-2012 Andreas Steffen
+ * Copyright (C) 2010-2015 Andreas Steffen
  * HSR Hochschule fuer Technik Rapperswil
  *
  * This program is free software; you can redistribute it and/or modify it
@@ -85,7 +85,7 @@ struct private_pb_tnc_batch_t {
 	pb_tnc_batch_t public;
 
 	/**
-	 * TNCC if TRUE, TNCS if FALSE
+	 * from TNC server if TRUE, from TNC client if FALSE
 	 */
 	bool is_server;
 
@@ -228,15 +228,15 @@ METHOD(pb_tnc_batch_t, build, void,
 	writer->destroy(writer);
 }
 
-static status_t process_batch_header(private_pb_tnc_batch_t *this,
-									 pb_tnc_state_machine_t *state_machine)
+METHOD(pb_tnc_batch_t, process_header, status_t,
+	private_pb_tnc_batch_t *this, bool directionality, bool is_server,
+	bool *from_server)
 {
 	bio_reader_t *reader;
 	pb_tnc_msg_t *msg;
 	pb_error_msg_t *err_msg;
 	u_int8_t version, flags, reserved, type;
 	u_int32_t batch_len;
-	bool directionality;
 
 	if (this->encoding.len < PB_TNC_BATCH_HEADER_SIZE)
 	{
@@ -267,13 +267,14 @@ static status_t process_batch_header(private_pb_tnc_batch_t *this,
 	}
 
 	/* Directionality */
-	directionality = (flags & PB_TNC_BATCH_FLAG_D) != PB_TNC_BATCH_FLAG_NONE;
-	if (directionality == this->is_server)
+	*from_server = (flags & PB_TNC_BATCH_FLAG_D) != PB_TNC_BATCH_FLAG_NONE;
+
+	if (directionality & (*from_server == is_server))
 	{
 		DBG1(DBG_TNC, "wrong Directionality: batch is from a PB %s",
-			 directionality ? "server" : "client");
+					   is_server ? "server" : "client");
 		msg = pb_error_msg_create_with_offset(TRUE, PEN_IETF,
-							PB_ERROR_INVALID_PARAMETER, 1);
+					   PB_ERROR_INVALID_PARAMETER, 1);
 		goto fatal;
 	}
 
@@ -287,17 +288,6 @@ static status_t process_batch_header(private_pb_tnc_batch_t *this,
 		goto fatal;
 	}
 
-	if (!state_machine->receive_batch(state_machine, this->type))
-	{
-		DBG1(DBG_TNC, "unexpected PB-TNC batch type: %N",
-					   pb_tnc_batch_type_names, this->type);
-		msg = pb_error_msg_create(TRUE, PEN_IETF,
-								  PB_ERROR_UNEXPECTED_BATCH_TYPE);
-		goto fatal;
-	}
-	DBG1(DBG_TNC, "processing PB-TNC %N batch", pb_tnc_batch_type_names,
-												this->type);
-
 	/* Batch Length */
 	if (this->encoding.len != batch_len)
 	{
@@ -310,17 +300,11 @@ static status_t process_batch_header(private_pb_tnc_batch_t *this,
 
 	this->offset = PB_TNC_BATCH_HEADER_SIZE;
 
-	/* Register an empty CDATA batch with the state machine */
-	if (this->type == PB_BATCH_CDATA)
-	{
-		state_machine->set_empty_cdata(state_machine,
-									   this->offset == this->encoding.len);
-	}
 	return SUCCESS;
 
 fatal:
 	this->errors->insert_last(this->errors, msg);
-	return FAILED;
+	return VERIFY_ERROR;
 }
 
 static status_t process_tnc_msg(private_pb_tnc_batch_t *this)
@@ -502,14 +486,26 @@ fatal:
 METHOD(pb_tnc_batch_t, process, status_t,
 	private_pb_tnc_batch_t *this, pb_tnc_state_machine_t *state_machine)
 {
-	status_t status;
+	pb_tnc_msg_t *msg;
+	status_t status = SUCCESS;
 
-	status = process_batch_header(this, state_machine);
-	if (status != SUCCESS)
+	if (!state_machine->receive_batch(state_machine, this->type))
 	{
+		DBG1(DBG_TNC, "unexpected PB-TNC batch type: %N",
+					   pb_tnc_batch_type_names, this->type);
+		msg = pb_error_msg_create(TRUE, PEN_IETF,
+								  PB_ERROR_UNEXPECTED_BATCH_TYPE);
+		this->errors->insert_last(this->errors, msg);
 		return FAILED;
 	}
 
+	/* Register an empty CDATA batch with the state machine */
+	if (this->type == PB_BATCH_CDATA)
+	{
+		state_machine->set_empty_cdata(state_machine,
+									   this->offset == this->encoding.len);
+	}
+
 	while (this->offset < this->encoding.len)
 	{
 		switch (process_tnc_msg(this))
@@ -585,7 +581,7 @@ pb_tnc_batch_t* pb_tnc_batch_create(bool is_server, pb_tnc_batch_type_t type,
 /**
  * See header
  */
-pb_tnc_batch_t* pb_tnc_batch_create_from_data(bool is_server, chunk_t data)
+pb_tnc_batch_t* pb_tnc_batch_create_from_data(chunk_t data)
 {
 	private_pb_tnc_batch_t *this;
 
@@ -595,12 +591,12 @@ pb_tnc_batch_t* pb_tnc_batch_create_from_data(bool is_server, chunk_t data)
 			.get_encoding = _get_encoding,
 			.add_msg = _add_msg,
 			.build = _build,
+			.process_header = _process_header,
 			.process = _process,
 			.create_msg_enumerator = _create_msg_enumerator,
 			.create_error_enumerator = _create_error_enumerator,
 			.destroy = _destroy,
 		},
-		.is_server = is_server,
 		.messages = linked_list_create(),
 		.errors = linked_list_create(),
 		.encoding = chunk_clone(data),
diff --git a/src/libtnccs/plugins/tnccs_20/batch/pb_tnc_batch.h b/src/libtnccs/plugins/tnccs_20/batch/pb_tnc_batch.h
index 106c5578c..6089c7d2e 100644
--- a/src/libtnccs/plugins/tnccs_20/batch/pb_tnc_batch.h
+++ b/src/libtnccs/plugins/tnccs_20/batch/pb_tnc_batch.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010-2012 Andreas Steffen
+ * Copyright (C) 2010-2015 Andreas Steffen
  * HSR Hochschule fuer Technik Rapperswil
  *
  * This program is free software; you can redistribute it and/or modify it
@@ -84,10 +84,21 @@ struct pb_tnc_batch_t {
 	void (*build)(pb_tnc_batch_t *this);
 
 	/**
+	 * Process the PB-TNC Batch header
+	 *
+	 * @param directionality	TRUE if no mutual TNC measurements
+	 * @param is_server			TRUE if called by TNC server
+	 * @param from_server		TRUE if sent by TNC server
+	 * @return					return processing status
+	 */
+	status_t (*process_header)(pb_tnc_batch_t *this, bool directionality,
+							   bool is_server, bool *from_server);
+
+	/**
 	 * Process the PB-TNC Batch
 	 *
-	 * @param				PB-TNC state machine
-	 * @return				return processing status
+	 * @param state_machine		PB-TNC state machine
+	 * @return					return processing status
 	 */
 	status_t (*process)(pb_tnc_batch_t *this,
 						pb_tnc_state_machine_t *state_machine);
@@ -95,14 +106,14 @@ struct pb_tnc_batch_t {
 	/**
 	 * Enumerates over all PB-TNC Messages
 	 *
-	 * @return				return message enumerator
+	 * @return					return message enumerator
 	 */
 	enumerator_t* (*create_msg_enumerator)(pb_tnc_batch_t *this);
 
 	/**
 	 * Enumerates over all parsing errors
 	 *
-	 * @return				return error enumerator
+	 * @return					return error enumerator
 	 */
 	enumerator_t* (*create_error_enumerator)(pb_tnc_batch_t *this);
 
@@ -115,9 +126,9 @@ struct pb_tnc_batch_t {
 /**
  * Create an empty PB-TNC Batch of a given type
  *
- * @param is_server			TRUE if server, FALSE if client
- * @param type				PB-TNC batch type
- * @param max_batch_len		maximum size the PB-TNC batch
+ * @param is_server				TRUE if server, FALSE if client
+ * @param type					PB-TNC batch type
+ * @param max_batch_len			maximum size the PB-TNC batch
  */
 pb_tnc_batch_t* pb_tnc_batch_create(bool is_server, pb_tnc_batch_type_t type,
 									size_t max_batch_len);
@@ -125,9 +136,8 @@ pb_tnc_batch_t* pb_tnc_batch_create(bool is_server, pb_tnc_batch_type_t type,
 /**
  * Create an unprocessed PB-TNC Batch from data
  *
- * @param is_server			TRUE if server, FALSE if client
  * @param  data				encoded PB-TNC batch
  */
-pb_tnc_batch_t* pb_tnc_batch_create_from_data(bool is_server, chunk_t data);
+pb_tnc_batch_t* pb_tnc_batch_create_from_data(chunk_t data);
 
 #endif /** PB_TNC_BATCH_H_ @}*/
diff --git a/src/libtnccs/plugins/tnccs_20/tnccs_20.c b/src/libtnccs/plugins/tnccs_20/tnccs_20.c
index 997771406..33b012880 100644
--- a/src/libtnccs/plugins/tnccs_20/tnccs_20.c
+++ b/src/libtnccs/plugins/tnccs_20/tnccs_20.c
@@ -15,30 +15,17 @@
  */
 
 #include "tnccs_20.h"
+#include "tnccs_20_handler.h"
+#include "tnccs_20_server.h"
+#include "tnccs_20_client.h"
 #include "batch/pb_tnc_batch.h"
 #include "messages/pb_tnc_msg.h"
 #include "messages/ietf/pb_pa_msg.h"
-#include "messages/ietf/pb_error_msg.h"
-#include "messages/ietf/pb_assessment_result_msg.h"
-#include "messages/ietf/pb_access_recommendation_msg.h"
-#include "messages/ietf/pb_remediation_parameters_msg.h"
-#include "messages/ietf/pb_reason_string_msg.h"
-#include "messages/ietf/pb_language_preference_msg.h"
-#include "messages/tcg/pb_pdp_referral_msg.h"
-#include "state_machine/pb_tnc_state_machine.h"
 
 #include <tncif_names.h>
 #include <tncif_pa_subtypes.h>
 
-#include <tnc/tnc.h>
-#include <tnc/tnccs/tnccs_manager.h>
-#include <tnc/imc/imc_manager.h>
-#include <tnc/imv/imv_manager.h>
-
-#include <threading/mutex.h>
 #include <utils/debug.h>
-#include <collections/linked_list.h>
-#include <pen/pen.h>
 
 typedef struct private_tnccs_20_t private_tnccs_20_t;
 
@@ -83,64 +70,49 @@ struct private_tnccs_20_t {
 	tnc_ift_type_t transport;
 
 	/**
-	 * Type of TNC client authentication
-	 */
-	u_int32_t auth_type;
-
-	/**
-	 * PB-TNC State Machine
-	 */
-	pb_tnc_state_machine_t *state_machine;
-
-	/**
-	 * Connection ID assigned to this TNCCS connection
+	 *  TNC IF-T transport protocol for EAP methods
 	 */
-	TNC_ConnectionID connection_id;
+	bool eap_transport;
 
 	/**
-	 * PB-TNC messages to be sent
+	 * Type of TNC client authentication
 	 */
-	linked_list_t *messages;
+	u_int32_t auth_type;
 
 	/**
-	 * Type of PB-TNC batch being constructed
+	 * Mutual TNC measurements
 	 */
-	pb_tnc_batch_type_t batch_type;
+	bool mutual;
 
 	/**
-	 * Maximum PB-TNC batch size
+	 * Direction the next batch will go to
 	 */
-	size_t max_batch_len;
+	bool to_server;
 
 	/**
-	 * Maximum PA-TNC message size
+	 * TNC Server
 	 */
-	size_t max_msg_len;
+	tnccs_20_handler_t *tnc_server;
 
 	/**
-	 * Mutex locking the batch in construction
+	 * TNC Client
 	 */
-	mutex_t *mutex;
+	tnccs_20_handler_t *tnc_client;
 
 	/**
-	 * Flag set while processing
+	 * Active TNCSS handler
 	 */
-	bool fatal_error;
+	tnccs_20_handler_t *tnccs_handler;
 
 	/**
-	 * Flag set by IMC/IMV RequestHandshakeRetry() function
+	 * Maximum PB-TNC batch size
 	 */
-	bool request_handshake_retry;
-
-	/**
-	  * SendMessage() by IMC/IMV only allowed if flag is set
-	  */
-	bool send_msg;
+	size_t max_batch_len;
 
 	/**
-	 * Set of IMV recommendations  (TNC Server only)
+	 * Maximum PA-TNC message size
 	 */
-	recommendations_t *recs;
+	size_t max_msg_len;
 
 	/**
 	 * Callback function to communicate recommendation (TNC Server only)
@@ -148,69 +120,30 @@ struct private_tnccs_20_t {
 	tnccs_cb_t callback;
 
 	/**
-	 * Data to pass to callback function (TNC Server only)
-	 */
-	void *cb_data;
-
-	/**
-	 * PDP server FQDN
-	 */
-	chunk_t pdp_server;
-
-	/**
-	 * PDP server port
-	 */
-	u_int16_t pdp_port;
-
-	/**
 	 * reference count
 	 */
 	refcount_t ref;
 
 };
 
-/**
- * If the batch type changes then delete all accumulated PB-TNC messages
- */
-void change_batch_type(private_tnccs_20_t *this, pb_tnc_batch_type_t batch_type)
-{
-	pb_tnc_msg_t *msg;
-
-	if (batch_type != this->batch_type)
-	{
-		if (this->batch_type != PB_BATCH_NONE)
-		{
-			DBG1(DBG_TNC, "cancelling PB-TNC %N batch",
-				 pb_tnc_batch_type_names, this->batch_type);
-
-			while (this->messages->remove_last(this->messages,
-											  (void**)&msg) == SUCCESS)
-			{
-				msg->destroy(msg);
-			}
-		}
-		this->batch_type = batch_type;
-	}
-}
-
 METHOD(tnccs_t, send_msg, TNC_Result,
 	private_tnccs_20_t* this, TNC_IMCID imc_id, TNC_IMVID imv_id,
-						      TNC_UInt32 msg_flags,
+							  TNC_UInt32 msg_flags,
 							  TNC_BufferReference msg,
 							  TNC_UInt32 msg_len,
-						      TNC_VendorID msg_vid,
-						      TNC_MessageSubtype msg_subtype)
+							  TNC_VendorID msg_vid,
+							  TNC_MessageSubtype msg_subtype)
 {
 	pb_tnc_msg_t *pb_tnc_msg;
-	pb_tnc_batch_type_t batch_type;
 	enum_name_t *pa_subtype_names;
 	bool excl;
 
-	if (!this->send_msg)
+	if (!this->tnccs_handler->get_send_flag(this->tnccs_handler))
 	{
 		DBG1(DBG_TNC, "%s %u not allowed to call SendMessage()",
-			this->is_server ? "IMV" : "IMC",
-			this->is_server ? imv_id : imc_id);
+					   this->to_server ? "IMC" : "IMV",
+					   this->to_server ? imc_id : imv_id);
+
 		return TNC_RESULT_ILLEGAL_OPERATION;
 	}
 	excl = (msg_flags & TNC_MESSAGE_FLAGS_EXCLUSIVE) != 0;
@@ -230,697 +163,106 @@ METHOD(tnccs_t, send_msg, TNC_Result,
 		DBG2(DBG_TNC, "creating PB-PA message type '%N' 0x%06x/0x%08x",
 					   pen_names, msg_vid, msg_vid, msg_subtype);
 	}
+	this->tnccs_handler->add_msg(this->tnccs_handler, pb_tnc_msg);
 
-	/* adding PA message to SDATA or CDATA batch only */
-	batch_type = this->is_server ? PB_BATCH_SDATA : PB_BATCH_CDATA;
-	this->mutex->lock(this->mutex);
-	if (this->batch_type == PB_BATCH_NONE)
-	{
-		this->batch_type = batch_type;
-	}
-	if (this->batch_type == batch_type)
-	{
-		this->messages->insert_last(this->messages, pb_tnc_msg);
-	}
-	else
-	{
-		pb_tnc_msg->destroy(pb_tnc_msg);
-	}
-	this->mutex->unlock(this->mutex);
 	return TNC_RESULT_SUCCESS;
 }
 
-/**
- * Handle a single PB-TNC IETF standard message according to its type
- */
-static void handle_ietf_message(private_tnccs_20_t *this, pb_tnc_msg_t *msg)
-{
-	pen_type_t msg_type = msg->get_type(msg);
-
-	switch (msg_type.type)
-	{
-		case PB_MSG_EXPERIMENTAL:
-			/* nothing to do */
-			break;
-		case PB_MSG_PA:
-		{
-			pb_pa_msg_t *pa_msg;
-			pen_type_t msg_subtype;
-			u_int16_t imc_id, imv_id;
-			chunk_t msg_body;
-			bool excl;
-			enum_name_t *pa_subtype_names;
-
-			pa_msg = (pb_pa_msg_t*)msg;
-			msg_subtype = pa_msg->get_subtype(pa_msg);
-			msg_body = pa_msg->get_body(pa_msg);
-			imc_id = pa_msg->get_collector_id(pa_msg);
-			imv_id = pa_msg->get_validator_id(pa_msg);
-			excl = pa_msg->get_exclusive_flag(pa_msg);
-
-			pa_subtype_names = get_pa_subtype_names(msg_subtype.vendor_id);
-			if (pa_subtype_names)
-			{
-				DBG2(DBG_TNC, "handling PB-PA message type '%N/%N' 0x%06x/0x%08x",
-					 pen_names, msg_subtype.vendor_id, pa_subtype_names,
-					 msg_subtype.type, msg_subtype.vendor_id, msg_subtype.type);
-			}
-			else
-			{
-				DBG2(DBG_TNC, "handling PB-PA message type '%N' 0x%06x/0x%08x",
-					 pen_names, msg_subtype.vendor_id, msg_subtype.vendor_id,
-					 msg_subtype.type);
-			}
-
-			this->send_msg = TRUE;
-			if (this->is_server)
-			{
-				tnc->imvs->receive_message(tnc->imvs, this->connection_id,
-										   excl, msg_body.ptr, msg_body.len,
-										   msg_subtype.vendor_id,
-										   msg_subtype.type, imc_id, imv_id);
-			}
-			else
-			{
-				tnc->imcs->receive_message(tnc->imcs, this->connection_id,
-										   excl, msg_body.ptr, msg_body.len,
-										   msg_subtype.vendor_id,
-										   msg_subtype.type, imv_id, imc_id);
-			}
-			this->send_msg = FALSE;
-			break;
-		}
-		case PB_MSG_ASSESSMENT_RESULT:
-		{
-			pb_assessment_result_msg_t *assess_msg;
-			u_int32_t result;
-
-			assess_msg = (pb_assessment_result_msg_t*)msg;
-			result = assess_msg->get_assessment_result(assess_msg);
-			DBG1(DBG_TNC, "PB-TNC assessment result is '%N'",
-				 TNC_IMV_Evaluation_Result_names, result);
-			break;
-		}
-		case PB_MSG_ACCESS_RECOMMENDATION:
-		{
-			pb_access_recommendation_msg_t *rec_msg;
-			pb_access_recommendation_code_t rec;
-			TNC_ConnectionState state = TNC_CONNECTION_STATE_ACCESS_NONE;
-
-			rec_msg = (pb_access_recommendation_msg_t*)msg;
-			rec = rec_msg->get_access_recommendation(rec_msg);
-			DBG1(DBG_TNC, "PB-TNC access recommendation is '%N'",
-						   pb_access_recommendation_code_names, rec);
-			switch (rec)
-			{
-				case PB_REC_ACCESS_ALLOWED:
-					state = TNC_CONNECTION_STATE_ACCESS_ALLOWED;
-					break;
-				case PB_REC_ACCESS_DENIED:
-					state = TNC_CONNECTION_STATE_ACCESS_NONE;
-					break;
-				case PB_REC_QUARANTINED:
-					state = TNC_CONNECTION_STATE_ACCESS_ISOLATED;
-			}
-			tnc->imcs->notify_connection_change(tnc->imcs, this->connection_id,
-												state);
-			break;
-		}
-		case PB_MSG_REMEDIATION_PARAMETERS:
-		{
-			pb_remediation_parameters_msg_t *rem_msg;
-			pen_type_t parameters_type;
-			chunk_t parameters, string, lang_code;
-
-			rem_msg = (pb_remediation_parameters_msg_t*)msg;
-			parameters_type = rem_msg->get_parameters_type(rem_msg);
-			parameters = rem_msg->get_parameters(rem_msg);
-
-			if (parameters_type.vendor_id == PEN_IETF)
-			{
-				switch (parameters_type.type)
-				{
-					case PB_REMEDIATION_URI:
-						DBG1(DBG_TNC, "remediation uri: %.*s",
-									   parameters.len, parameters.ptr);
-						break;
-					case PB_REMEDIATION_STRING:
-						string = rem_msg->get_string(rem_msg, &lang_code);
-						DBG1(DBG_TNC, "remediation string: [%.*s]\n%.*s",
-									   lang_code.len, lang_code.ptr,
-									   string.len, string.ptr);
-						break;
-					default:
-						DBG1(DBG_TNC, "remediation parameters: %B", &parameters);
-				}
-			}
-			else
-			{
-				DBG1(DBG_TNC, "remediation parameters: %B", &parameters);
-			}
-			break;
-		}
-		case PB_MSG_ERROR:
-		{
-			pb_error_msg_t *err_msg;
-			bool fatal;
-			u_int32_t vendor_id;
-			u_int16_t error_code;
-
-			err_msg = (pb_error_msg_t*)msg;
-			fatal = err_msg->get_fatal_flag(err_msg);
-			vendor_id = err_msg->get_vendor_id(err_msg);
-			error_code = err_msg->get_error_code(err_msg);
-
-			if (fatal)
-			{
-				this->fatal_error = TRUE;
-			}
-
-			if (vendor_id == PEN_IETF)
-			{
-				switch (error_code)
-				{
-					case PB_ERROR_INVALID_PARAMETER:
-					case PB_ERROR_UNSUPPORTED_MANDATORY_MSG:
-						DBG1(DBG_TNC, "received %s PB-TNC error '%N' "
-									  "(offset %u bytes)",
-									  fatal ? "fatal" : "non-fatal",
-									  pb_tnc_error_code_names, error_code,
-									  err_msg->get_offset(err_msg));
-						break;
-					case PB_ERROR_VERSION_NOT_SUPPORTED:
-						DBG1(DBG_TNC, "received %s PB-TNC error '%N' "
-									  "caused by bad version 0x%02x",
-									  fatal ? "fatal" : "non-fatal",
-									  pb_tnc_error_code_names, error_code,
-									  err_msg->get_bad_version(err_msg));
-						break;
-					case PB_ERROR_UNEXPECTED_BATCH_TYPE:
-					case PB_ERROR_LOCAL_ERROR:
-					default:
-						DBG1(DBG_TNC, "received %s PB-TNC error '%N'",
-									  fatal ? "fatal" : "non-fatal",
-									  pb_tnc_error_code_names, error_code);
-						break;
-				}
-			}
-			else
-			{
-				DBG1(DBG_TNC, "received %s PB-TNC error (%u) "
-							  "with Vendor ID 0x%06x",
-							  fatal ? "fatal" : "non-fatal",
-							  error_code, vendor_id);
-			}
-			break;
-		}
-		case PB_MSG_LANGUAGE_PREFERENCE:
-		{
-			pb_language_preference_msg_t *lang_msg;
-			chunk_t lang;
-
-			lang_msg = (pb_language_preference_msg_t*)msg;
-			lang = lang_msg->get_language_preference(lang_msg);
-
-			if (this->recs)
-			{
-				DBG2(DBG_TNC, "setting language preference to '%.*s'",
-					 (int)lang.len, lang.ptr);
-				this->recs->set_preferred_language(this->recs, lang);
-			}
-			break;
-		}
-		case PB_MSG_REASON_STRING:
-		{
-			pb_reason_string_msg_t *reason_msg;
-			chunk_t reason_string, language_code;
-
-			reason_msg = (pb_reason_string_msg_t*)msg;
-			reason_string = reason_msg->get_reason_string(reason_msg);
-			language_code = reason_msg->get_language_code(reason_msg);
-			DBG1(DBG_TNC, "reason string is '%.*s' [%.*s]",
-				 (int)reason_string.len, reason_string.ptr,
-				 (int)language_code.len, language_code.ptr);
-			break;
-		}
-		default:
-			break;
-	}
-}
-
-/**
- * Handle a single PB-TNC TCG standard message according to its type
- */
-static void handle_tcg_message(private_tnccs_20_t *this, pb_tnc_msg_t *msg)
-{
-	pen_type_t msg_type = msg->get_type(msg);
-
-	switch (msg_type.type)
-	{
-		case PB_TCG_MSG_PDP_REFERRAL:
-		{
-			pb_pdp_referral_msg_t *pdp_msg;
-			pen_type_t pdp_id_type;
-			u_int8_t pdp_protocol;
-
-			pdp_msg = (pb_pdp_referral_msg_t*)msg;
-			pdp_id_type = pdp_msg->get_identifier_type(pdp_msg);
-
-			if (pdp_id_type.vendor_id == PEN_TCG &&
-				pdp_id_type.type == PB_PDP_ID_FQDN)
-			{
-				this->pdp_server = chunk_clone(pdp_msg->get_fqdn(pdp_msg,
-										 &pdp_protocol, &this->pdp_port));
-				if (pdp_protocol != 0)
-				{
-					DBG1(DBG_TNC, "unsupported PDP transport protocol");
-					break;
-				}
-				DBG1(DBG_TNC, "PDP server '%.*s' is listening on port %u",
-							   this->pdp_server.len, this->pdp_server.ptr,
-							   this->pdp_port);
-			}
-			break;
-		}
-		default:
-			break;
-	}
-}
-
-/**
- * Handle a single PB-TNC message according to its type
- */
-static void handle_message(private_tnccs_20_t *this, pb_tnc_msg_t *msg)
-{
-	pen_type_t msg_type = msg->get_type(msg);
-
-	switch (msg_type.vendor_id)
-	{
-		case PEN_IETF:
-			handle_ietf_message(this, msg);
-			break;
-		case PEN_TCG:
-			handle_tcg_message(this, msg);
-			break;
-		default:
-			break;
-	}
-}
-
-/**
- *  Build a CRETRY or SRETRY batch
- */
-static void build_retry_batch(private_tnccs_20_t *this)
-{
-	pb_tnc_batch_type_t batch_retry_type;
-
-	batch_retry_type = this->is_server ? PB_BATCH_SRETRY : PB_BATCH_CRETRY;
-	if (this->batch_type == batch_retry_type)
-	{
-		/* retry batch has already been selected */
-		return;
-	}
-
-	change_batch_type(this, batch_retry_type);
-
-	if (this->is_server)
-	{
-		this->recs->clear_recommendation(this->recs);
-		tnc->imvs->notify_connection_change(tnc->imvs, this->connection_id,
-											TNC_CONNECTION_STATE_HANDSHAKE);
-	}
-}
-
 METHOD(tls_t, process, status_t,
 	private_tnccs_20_t *this, void *buf, size_t buflen)
 {
 	chunk_t data;
 	pb_tnc_batch_t *batch;
-	pb_tnc_msg_t *msg;
-	enumerator_t *enumerator;
-	identification_t *pdp_server;
-	u_int16_t *pdp_port;
+	bool from_server, mutual;
 	status_t status;
 
-	if (this->is_server && !this->connection_id)
+	/* On arrival of first PB-TNC batch create TNC server */
+	if (this->is_server && !this->tnc_server)
 	{
-		this->connection_id = tnc->tnccs->create_connection(tnc->tnccs,
-									TNCCS_2_0, (tnccs_t*)this, _send_msg,
-									&this->request_handshake_retry,
-									this->max_msg_len, &this->recs);
-		if (!this->connection_id)
+		this->tnc_server = tnccs_20_server_create(&this->public, _send_msg,
+									this->max_batch_len, this->max_msg_len,
+									this->eap_transport);
+		if (!this->tnc_server)
 		{
 			return FAILED;
 		}
-		tnc->imvs->notify_connection_change(tnc->imvs, this->connection_id,
-											TNC_CONNECTION_STATE_CREATE);
-		tnc->imvs->notify_connection_change(tnc->imvs, this->connection_id,
-											TNC_CONNECTION_STATE_HANDSHAKE);
-
-		/* Send a PB-TNC TCG PDP Referral message if PDP is known */
-		pdp_server = (identification_t*)lib->get(lib, "pt-tls-server");
-		pdp_port = (u_int16_t*)lib->get(lib, "pt-tls-port");
-
-		if ((this->transport ==	TNC_IFT_EAP_1_1 ||
-			 this->transport == TNC_IFT_EAP_2_0) &&	pdp_server && pdp_port)
-		{
-			msg = pb_pdp_referral_msg_create_from_fqdn(
-						pdp_server->get_encoding(pdp_server), *pdp_port);
-			this->messages->insert_last(this->messages, msg);
-		}
-
+		this->tnccs_handler = this->tnc_server;
+		this->tnccs_handler->begin_handshake(this->tnccs_handler);
 	}
 
 	data = chunk_create(buf, buflen);
-	DBG1(DBG_TNC, "received TNCCS batch (%u bytes) for Connection ID %u",
-				   data.len, this->connection_id);
+	DBG1(DBG_TNC, "received TNCCS batch (%u bytes)", data.len);
 	DBG3(DBG_TNC, "%B", &data);
-	batch = pb_tnc_batch_create_from_data(this->is_server, data);
-	status = batch->process(batch, this->state_machine);
 
-	if (status != FAILED)
-	{
-		enumerator_t *enumerator;
-		pb_tnc_msg_t *msg;
-		pb_tnc_batch_type_t batch_type;
-		bool empty = TRUE;
+	/* Has a mutual connection been established? */
+	mutual = this->tnc_client && this->tnc_server;
 
-		batch_type = batch->get_type(batch);
+	/* Parse the header of the received PB-TNC batch */
+	batch = pb_tnc_batch_create_from_data(data);
+	status = batch->process_header(batch, !mutual, this->is_server,
+								   &from_server);
+	this->to_server = mutual ? from_server : !this->is_server;
 
-		if (batch_type == PB_BATCH_CRETRY)
-		{
-			/* Send an SRETRY batch in response */
-			this->mutex->lock(this->mutex);
-			build_retry_batch(this);
-			this->mutex->unlock(this->mutex);
-		}
-		else if (batch_type == PB_BATCH_SRETRY)
-		{
-			/* Restart the measurements */
-			tnc->imcs->notify_connection_change(tnc->imcs,
-			this->connection_id, TNC_CONNECTION_STATE_HANDSHAKE);
-			this->send_msg = TRUE;
-			tnc->imcs->begin_handshake(tnc->imcs, this->connection_id);
-			this->send_msg = FALSE;
-		}
-
-		enumerator = batch->create_msg_enumerator(batch);
-		while (enumerator->enumerate(enumerator, &msg))
-		{
-			handle_message(this, msg);
-			empty = FALSE;
-		}
-		enumerator->destroy(enumerator);
-
-		/* received an empty CLOSE batch from PB-TNC client */
-		if (this->is_server && batch_type == PB_BATCH_CLOSE && empty)
-		{
-			batch->destroy(batch);
-			if (this->fatal_error)
-			{
-				DBG1(DBG_TNC, "a fatal PB-TNC error occurred, "
-							  "terminating connection");
-				return FAILED;
-			}
-			else
-			{
-				return SUCCESS;
-			}
-		}
-
-		this->send_msg = TRUE;
-		if (this->is_server)
-		{
-			tnc->imvs->batch_ending(tnc->imvs, this->connection_id);
-		}
-		else
-		{
-			tnc->imcs->batch_ending(tnc->imcs, this->connection_id);
-		}
-		this->send_msg = FALSE;
-	}
+	/* Set active TNCCS handler */
+	this->tnccs_handler = this->to_server ? this->tnc_client : this->tnc_server;	
+	DBG2(DBG_TNC, "TNC %s is handling the connection",
+				   this->to_server ? "client" : "server");
 
-	switch (status)
+	if (status == SUCCESS)
 	{
-		case FAILED:
-			this->fatal_error = TRUE;
-			this->mutex->lock(this->mutex);
-			change_batch_type(this, PB_BATCH_CLOSE);
-			this->mutex->unlock(this->mutex);
-			/* fall through to add error messages to outbound batch */
-		case VERIFY_ERROR:
-			enumerator = batch->create_error_enumerator(batch);
-			while (enumerator->enumerate(enumerator, &msg))
-			{
-				this->mutex->lock(this->mutex);
-				this->messages->insert_last(this->messages, msg->get_ref(msg));
-				this->mutex->unlock(this->mutex);
-			}
-			enumerator->destroy(enumerator);
-			break;
-		case SUCCESS:
-		default:
-			break;
+		status = this->tnccs_handler->process(this->tnccs_handler, batch);
 	}
-	batch->destroy(batch);
-
-	return NEED_MORE;
-}
-
-/**
- *  Build a RESULT batch if a final recommendation is available
- */
-static void check_and_build_recommendation(private_tnccs_20_t *this)
-{
-	TNC_IMV_Action_Recommendation rec;
-	TNC_IMV_Evaluation_Result eval;
-	TNC_ConnectionState state;
-	TNC_IMVID id;
-	chunk_t reason, language;
-	enumerator_t *enumerator;
-	pb_tnc_msg_t *msg;
-	pb_access_recommendation_code_t pb_rec;
-
-	if (!this->recs->have_recommendation(this->recs, &rec, &eval))
+	if (status == VERIFY_ERROR)
 	{
-		tnc->imvs->solicit_recommendation(tnc->imvs, this->connection_id);
+		this->tnccs_handler->handle_errors(this->tnccs_handler, batch);
+		status = NEED_MORE;
 	}
-	if (this->recs->have_recommendation(this->recs, &rec, &eval))
-	{
-		this->batch_type = PB_BATCH_RESULT;
-
-		msg = pb_assessment_result_msg_create(eval);
-		this->messages->insert_last(this->messages, msg);
-
-		/**
-		 * Map IMV Action Recommendation codes to PB Access Recommendation codes
-		 * and communicate Access Recommendation to IMVs
-		 */
-		switch (rec)
-		{
-			case TNC_IMV_ACTION_RECOMMENDATION_ALLOW:
-				state = TNC_CONNECTION_STATE_ACCESS_ALLOWED;
-				pb_rec = PB_REC_ACCESS_ALLOWED;
-				break;
-			case TNC_IMV_ACTION_RECOMMENDATION_ISOLATE:
-				state = TNC_CONNECTION_STATE_ACCESS_ISOLATED;
-				pb_rec = PB_REC_QUARANTINED;
-				break;
-			case TNC_IMV_ACTION_RECOMMENDATION_NO_ACCESS:
-			case TNC_IMV_ACTION_RECOMMENDATION_NO_RECOMMENDATION:
-			default:
-				state = TNC_CONNECTION_STATE_ACCESS_NONE;
-				pb_rec = PB_REC_ACCESS_DENIED;
-		}
-		tnc->imvs->notify_connection_change(tnc->imvs, this->connection_id,
-											state);
-
-		msg = pb_access_recommendation_msg_create(pb_rec);
-		this->messages->insert_last(this->messages, msg);
+	batch->destroy(batch);
 
-		enumerator = this->recs->create_reason_enumerator(this->recs);
-		while (enumerator->enumerate(enumerator, &id, &reason, &language))
-		{
-			msg = pb_reason_string_msg_create(reason, language);
-			this->messages->insert_last(this->messages, msg);
-		}
-		enumerator->destroy(enumerator);
-	}
+	return status;
 }
 
 METHOD(tls_t, build, status_t,
 	private_tnccs_20_t *this, void *buf, size_t *buflen, size_t *msglen)
 {
 	status_t status;
-	pb_tnc_state_t state;
-
-	/* Initialize the connection */
-	if (!this->is_server && !this->connection_id)
-	{
-		pb_tnc_msg_t *msg;
-		char *pref_lang;
-
-		this->connection_id = tnc->tnccs->create_connection(tnc->tnccs,
-										TNCCS_2_0, (tnccs_t*)this, _send_msg,
-										&this->request_handshake_retry,
-										this->max_msg_len, NULL);
-		if (!this->connection_id)
-		{
-			return FAILED;
-		}
-
-		/* Create PB-TNC Language Preference message */
-		pref_lang = tnc->imcs->get_preferred_language(tnc->imcs);
-		msg = pb_language_preference_msg_create(chunk_create(pref_lang,
-													strlen(pref_lang)));
-		this->mutex->lock(this->mutex);
-		this->batch_type = PB_BATCH_CDATA;
-		this->messages->insert_last(this->messages, msg);
-		this->mutex->unlock(this->mutex);
-
-		tnc->imcs->notify_connection_change(tnc->imcs, this->connection_id,
-											TNC_CONNECTION_STATE_CREATE);
-		tnc->imcs->notify_connection_change(tnc->imcs, this->connection_id,
-											TNC_CONNECTION_STATE_HANDSHAKE);
-		this->send_msg = TRUE;
-		tnc->imcs->begin_handshake(tnc->imcs, this->connection_id);
-		this->send_msg = FALSE;
-	}
-
-	state = this->state_machine->get_state(this->state_machine);
-
-	if (this->fatal_error && state == PB_STATE_END)
-	{
-		DBG1(DBG_TNC, "a fatal PB-TNC error occurred, terminating connection");
-		return FAILED;
-	}
-
-	/* Do not allow any asynchronous IMCs or IMVs to add additional messages */
-	this->mutex->lock(this->mutex);
-
-	if (this->request_handshake_retry)
-	{
-		if (state != PB_STATE_INIT)
-		{
-			build_retry_batch(this);
-		}
-
-		/* Reset the flag for the next handshake retry request */
-		this->request_handshake_retry = FALSE;
-	}
-
-	if (this->is_server &&  state == PB_STATE_SERVER_WORKING &&
-		this->recs->have_recommendation(this->recs, NULL, NULL))
-	{
-		check_and_build_recommendation(this);
-	}
 
-	if (this->batch_type == PB_BATCH_NONE)
+	if (this->to_server)
 	{
-		if (this->is_server)
-		{
-			if (state == PB_STATE_SERVER_WORKING)
-			{
-				if (this->state_machine->get_empty_cdata(this->state_machine))
-				{
-					check_and_build_recommendation(this);
-				}
-				else
-				{
-					DBG2(DBG_TNC, "no recommendation available yet, "
-								  "sending empty PB-TNC SDATA batch");
-					this->batch_type = PB_BATCH_SDATA;
-				}
-			}
-		}
-		else
+		/* Before sending the first PB-TNC batch create TNC client */
+		if (!this->tnc_client)
 		{
-			switch (state)
+			DBG2(DBG_TNC, "TNC client is handling the connection");
+			this->tnc_client = tnccs_20_client_create(&this->public, _send_msg,
+													  this->max_batch_len,
+													  this->max_msg_len);
+			if (!this->tnc_client)
 			{
-				case PB_STATE_CLIENT_WORKING:
-					DBG2(DBG_TNC, "no client data to send, "
-								  "sending empty PB-TNC CDATA batch");
-					this->batch_type = PB_BATCH_CDATA;
-					break;
-				case PB_STATE_DECIDED:
-					/**
-					 * In the DECIDED state and if no CRETRY is under way,
-					 * a PB-TNC client replies with an empty CLOSE batch.
-					 */
-					this->batch_type = PB_BATCH_CLOSE;
-					break;
-				default:
-					break;
+				status = FAILED;
 			}
+			this->tnccs_handler = this->tnc_client;
+			this->tnccs_handler->begin_handshake(this->tnccs_handler);		
 		}
 	}
-
-	if (this->batch_type != PB_BATCH_NONE)
+	else
 	{
-		pb_tnc_batch_t *batch;
-		pb_tnc_msg_t *msg;
-		chunk_t data;
-		int msg_count;
-		enumerator_t *enumerator;
-
-		if (this->state_machine->send_batch(this->state_machine, this->batch_type))
+		/* Before sending the first PB-TNC batch create TNC server */
+		if (!this->tnc_server)
 		{
-			batch = pb_tnc_batch_create(this->is_server, this->batch_type,
-										min(this->max_batch_len, *buflen));
-
-			enumerator = this->messages->create_enumerator(this->messages);
-			while (enumerator->enumerate(enumerator, &msg))
-			{
-				if (batch->add_msg(batch, msg))
-				{
-					this->messages->remove_at(this->messages, enumerator);
-				}
-				else
-				{
-					break;
-				}
-			}
-			enumerator->destroy(enumerator);
-
-			batch->build(batch);
-			data = batch->get_encoding(batch);
-			DBG1(DBG_TNC, "sending PB-TNC %N batch (%d bytes) for Connection ID %u",
-						   pb_tnc_batch_type_names, this->batch_type, data.len,
-						   this->connection_id);
-			DBG3(DBG_TNC, "%B", &data);
-
-			*buflen = data.len;
-			*msglen = 0;
-			memcpy(buf, data.ptr, *buflen);
-			batch->destroy(batch);
-
-			msg_count = this->messages->get_count(this->messages);
-			if (msg_count)
-			{
-				DBG2(DBG_TNC, "queued %d PB-TNC message%s for next %N batch",
-					 msg_count, (msg_count == 1) ? "" : "s",
-					 pb_tnc_batch_type_names, this->batch_type);
-			}
-			else
+			DBG2(DBG_TNC, "TNC server is handling the connection");
+			this->tnc_server = tnccs_20_server_create(&this->public, _send_msg,
+										this->max_batch_len, this->max_msg_len,
+										this->eap_transport);
+			if (!this->tnc_server)
 			{
-				this->batch_type = PB_BATCH_NONE;
+				status = FAILED;
 			}
-
-			status = ALREADY_DONE;
-		}
-		else
-		{
-			change_batch_type(this, PB_BATCH_NONE);
-			status = INVALID_STATE;
+			this->tnccs_handler = this->tnc_server;
+			this->tnccs_handler->begin_handshake(this->tnccs_handler);		
 		}
 	}
-	else
-	{
-		DBG1(DBG_TNC, "no PB-TNC batch to send");
-		status = INVALID_STATE;
-	}
-	this->mutex->unlock(this->mutex);
-
+	status = this->tnccs_handler->build(this->tnccs_handler, buf, buflen, msglen);
+	
 	return status;
 }
 
@@ -961,14 +303,17 @@ METHOD(tls_t, is_complete, bool,
 	TNC_IMV_Action_Recommendation rec;
 	TNC_IMV_Evaluation_Result eval;
 
-	if (this->recs && this->recs->have_recommendation(this->recs, &rec, &eval))
+	if (this->tnc_server)
 	{
-		return this->callback ? this->callback(rec, eval) : TRUE;
-	}
-	else
-	{
-		return FALSE;
+		tnccs_20_server_t *tnc_server;
+
+		tnc_server = (tnccs_20_server_t*)this->tnc_server;
+		if (tnc_server->have_recommendation(tnc_server, &rec, &eval))
+		{
+			return this->callback ? this->callback(rec, eval) : TRUE;
+		}
 	}
+	return FALSE;
 }
 
 METHOD(tls_t, get_eap_msk, chunk_t,
@@ -982,17 +327,12 @@ METHOD(tls_t, destroy, void,
 {
 	if (ref_put(&this->ref))
 	{
-		tnc->tnccs->remove_connection(tnc->tnccs, this->connection_id,
-												  this->is_server);
+		DESTROY_IF(this->tnc_server);
+		DESTROY_IF(this->tnc_client);
 		this->server_id->destroy(this->server_id);
 		this->peer_id->destroy(this->peer_id);
 		this->server_ip->destroy(this->server_ip);
 		this->peer_ip->destroy(this->peer_ip);
-		this->state_machine->destroy(this->state_machine);
-		this->mutex->destroy(this->mutex);
-		this->messages->destroy_offset(this->messages,
-									   offsetof(pb_tnc_msg_t, destroy));
-		free(this->pdp_server.ptr);
 		free(this);
 	}
 }
@@ -1036,9 +376,19 @@ METHOD(tnccs_t, set_auth_type, void,
 METHOD(tnccs_t, get_pdp_server, chunk_t,
 	private_tnccs_20_t *this, u_int16_t *port)
 {
-	*port = this->pdp_port;
+	if (this->tnc_client)
+	{
+		tnccs_20_client_t *tnc_client;
+
+		tnc_client = (tnccs_20_client_t*)this->tnc_client;
 
-	return this->pdp_server;
+		return tnc_client->get_pdp_server(tnc_client, port);
+	}
+	else
+	{
+		*port = 0;
+		return chunk_empty;
+	}
 }
 
 METHOD(tnccs_t, get_ref, tnccs_t*,
@@ -1114,15 +464,15 @@ tnccs_t* tnccs_20_create(bool is_server, identification_t *server_id,
 			.get_ref = _get_ref,
 		},
 		.is_server = is_server,
+		.to_server = !is_server,
 		.server_id = server_id->clone(server_id),
 		.peer_id = peer_id->clone(peer_id),
 		.server_ip = server_ip->clone(server_ip),
 		.peer_ip = peer_ip->clone(peer_ip),
 		.transport = transport,
+		.eap_transport = transport == TNC_IFT_EAP_1_1 ||
+						 transport == TNC_IFT_EAP_2_0,
 		.callback = cb,
-		.state_machine = pb_tnc_state_machine_create(is_server),
-		.mutex = mutex_create(MUTEX_TYPE_DEFAULT),
-		.messages = linked_list_create(),
 		.max_batch_len = max_batch_size,
 		.max_msg_len = max_message_size,
 		.ref = 1,
diff --git a/src/libtnccs/plugins/tnccs_20/tnccs_20_client.c b/src/libtnccs/plugins/tnccs_20/tnccs_20_client.c
new file mode 100644
index 000000000..44011424e
--- /dev/null
+++ b/src/libtnccs/plugins/tnccs_20/tnccs_20_client.c
@@ -0,0 +1,726 @@
+/*
+ * Copyright (C) 2015 Andreas Steffen
+ * HSR Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "tnccs_20_client.h"
+#include "messages/pb_tnc_msg.h"
+#include "messages/ietf/pb_pa_msg.h"
+#include "messages/ietf/pb_error_msg.h"
+#include "messages/ietf/pb_assessment_result_msg.h"
+#include "messages/ietf/pb_access_recommendation_msg.h"
+#include "messages/ietf/pb_remediation_parameters_msg.h"
+#include "messages/ietf/pb_reason_string_msg.h"
+#include "messages/ietf/pb_language_preference_msg.h"
+#include "messages/tcg/pb_pdp_referral_msg.h"
+#include "state_machine/pb_tnc_state_machine.h"
+
+#include <tncif_names.h>
+#include <tncif_pa_subtypes.h>
+
+#include <tnc/tnc.h>
+#include <tnc/tnccs/tnccs_manager.h>
+#include <tnc/imc/imc_manager.h>
+
+#include <threading/mutex.h>
+#include <utils/debug.h>
+#include <collections/linked_list.h>
+#include <pen/pen.h>
+
+typedef struct private_tnccs_20_client_t private_tnccs_20_client_t;
+
+/**
+ * Private data of a tnccs_20_client_t object.
+ */
+struct private_tnccs_20_client_t {
+
+	/**
+	 * Public tnccs_20_client_t interface.
+	 */
+	tnccs_20_client_t public;
+
+	/**
+	 * PB-TNC State Machine
+	 */
+	pb_tnc_state_machine_t *state_machine;
+
+	/**
+	 * Connection ID assigned to this TNCCS connection
+	 */
+	TNC_ConnectionID connection_id;
+
+	/**
+	 * PB-TNC messages to be sent
+	 */
+	linked_list_t *messages;
+
+	/**
+	 * Type of PB-TNC batch being constructed
+	 */
+	pb_tnc_batch_type_t batch_type;
+
+	/**
+	 * Maximum PB-TNC batch size
+	 */
+	size_t max_batch_len;
+
+	/**
+	 * Mutex locking the batch in construction
+	 */
+	mutex_t *mutex;
+
+	/**
+	 * Flag set while processing
+	 */
+	bool fatal_error;
+
+	/**
+	 * Flag set by IMC RequestHandshakeRetry() function
+	 */
+	bool request_handshake_retry;
+
+	/**
+	  * SendMessage() by IMC only allowed if flag is set
+	  */
+	bool send_msg;
+
+	/**
+	 * PDP server FQDN
+	 */
+	chunk_t pdp_server;
+
+	/**
+	 * PDP server port
+	 */
+	u_int16_t pdp_port;
+
+};
+
+/**
+ * The following function is shared with the tnccs_20_server class
+ */
+void tnccs_20_handle_ietf_error_msg(pb_tnc_msg_t *msg, bool *fatal_error)
+{
+	pb_error_msg_t *err_msg;
+	u_int32_t vendor_id;
+	u_int16_t error_code;
+	bool fatal;
+
+	err_msg = (pb_error_msg_t*)msg;
+	fatal = err_msg->get_fatal_flag(err_msg);
+	vendor_id = err_msg->get_vendor_id(err_msg);
+	error_code = err_msg->get_error_code(err_msg);
+
+	if (fatal)
+	{
+		*fatal_error = TRUE;
+	}
+
+	if (vendor_id == PEN_IETF)
+	{
+		switch (error_code)
+		{
+			case PB_ERROR_INVALID_PARAMETER:
+			case PB_ERROR_UNSUPPORTED_MANDATORY_MSG:
+				DBG1(DBG_TNC, "received %s PB-TNC error '%N' (offset %u bytes)",
+							  fatal ? "fatal" : "non-fatal",
+							  pb_tnc_error_code_names, error_code,
+							  err_msg->get_offset(err_msg));
+				break;
+			case PB_ERROR_VERSION_NOT_SUPPORTED:
+				DBG1(DBG_TNC, "received %s PB-TNC error '%N' "
+							  "caused by bad version 0x%02x",
+							  fatal ? "fatal" : "non-fatal",
+							  pb_tnc_error_code_names, error_code,
+							  err_msg->get_bad_version(err_msg));
+				break;
+			case PB_ERROR_UNEXPECTED_BATCH_TYPE:
+			case PB_ERROR_LOCAL_ERROR:
+			default:
+				DBG1(DBG_TNC, "received %s PB-TNC error '%N'",
+							  fatal ? "fatal" : "non-fatal",
+							  pb_tnc_error_code_names, error_code);
+				break;
+		}
+	}
+	else
+	{
+		DBG1(DBG_TNC, "received %s PB-TNC error (%u) with Vendor ID 0x%06x",
+					  fatal ? "fatal" : "non-fatal", error_code, vendor_id);
+	}
+}
+
+/**
+ * If the batch type changes then delete all accumulated PB-TNC messages
+ */
+static void change_batch_type(private_tnccs_20_client_t *this,
+							  pb_tnc_batch_type_t batch_type)
+{
+	pb_tnc_msg_t *msg;
+
+	if (batch_type != this->batch_type)
+	{
+		if (this->batch_type != PB_BATCH_NONE)
+		{
+			DBG1(DBG_TNC, "cancelling PB-TNC %N batch",
+				 pb_tnc_batch_type_names, this->batch_type);
+
+			while (this->messages->remove_last(this->messages,
+											  (void**)&msg) == SUCCESS)
+			{
+				msg->destroy(msg);
+			}
+		}
+		this->batch_type = batch_type;
+	}
+}
+
+/**
+ * Handle a single PB-TNC IETF standard message according to its type
+ */
+static void handle_ietf_message(private_tnccs_20_client_t *this, pb_tnc_msg_t *msg)
+{
+	pen_type_t msg_type = msg->get_type(msg);
+
+	switch (msg_type.type)
+	{
+		case PB_MSG_EXPERIMENTAL:
+			/* nothing to do */
+			break;
+		case PB_MSG_PA:
+		{
+			pb_pa_msg_t *pa_msg;
+			pen_type_t msg_subtype;
+			u_int16_t imc_id, imv_id;
+			chunk_t msg_body;
+			bool excl;
+			enum_name_t *pa_subtype_names;
+
+			pa_msg = (pb_pa_msg_t*)msg;
+			msg_subtype = pa_msg->get_subtype(pa_msg);
+			msg_body = pa_msg->get_body(pa_msg);
+			imc_id = pa_msg->get_collector_id(pa_msg);
+			imv_id = pa_msg->get_validator_id(pa_msg);
+			excl = pa_msg->get_exclusive_flag(pa_msg);
+
+			pa_subtype_names = get_pa_subtype_names(msg_subtype.vendor_id);
+			if (pa_subtype_names)
+			{
+				DBG2(DBG_TNC, "handling PB-PA message type '%N/%N' 0x%06x/0x%08x",
+					 pen_names, msg_subtype.vendor_id, pa_subtype_names,
+					 msg_subtype.type, msg_subtype.vendor_id, msg_subtype.type);
+			}
+			else
+			{
+				DBG2(DBG_TNC, "handling PB-PA message type '%N' 0x%06x/0x%08x",
+					 pen_names, msg_subtype.vendor_id, msg_subtype.vendor_id,
+					 msg_subtype.type);
+			}
+			this->send_msg = TRUE;
+			tnc->imcs->receive_message(tnc->imcs, this->connection_id,
+									   excl, msg_body.ptr, msg_body.len,
+									   msg_subtype.vendor_id,
+									   msg_subtype.type, imv_id, imc_id);
+			this->send_msg = FALSE;
+			break;
+		}
+		case PB_MSG_ASSESSMENT_RESULT:
+		{
+			pb_assessment_result_msg_t *assess_msg;
+			u_int32_t result;
+
+			assess_msg = (pb_assessment_result_msg_t*)msg;
+			result = assess_msg->get_assessment_result(assess_msg);
+			DBG1(DBG_TNC, "PB-TNC assessment result is '%N'",
+				 TNC_IMV_Evaluation_Result_names, result);
+			break;
+		}
+		case PB_MSG_ACCESS_RECOMMENDATION:
+		{
+			pb_access_recommendation_msg_t *rec_msg;
+			pb_access_recommendation_code_t rec;
+			TNC_ConnectionState state = TNC_CONNECTION_STATE_ACCESS_NONE;
+
+			rec_msg = (pb_access_recommendation_msg_t*)msg;
+			rec = rec_msg->get_access_recommendation(rec_msg);
+			DBG1(DBG_TNC, "PB-TNC access recommendation is '%N'",
+						   pb_access_recommendation_code_names, rec);
+			switch (rec)
+			{
+				case PB_REC_ACCESS_ALLOWED:
+					state = TNC_CONNECTION_STATE_ACCESS_ALLOWED;
+					break;
+				case PB_REC_ACCESS_DENIED:
+					state = TNC_CONNECTION_STATE_ACCESS_NONE;
+					break;
+				case PB_REC_QUARANTINED:
+					state = TNC_CONNECTION_STATE_ACCESS_ISOLATED;
+			}
+			tnc->imcs->notify_connection_change(tnc->imcs, this->connection_id,
+												state);
+			break;
+		}
+		case PB_MSG_REMEDIATION_PARAMETERS:
+		{
+			pb_remediation_parameters_msg_t *rem_msg;
+			pen_type_t parameters_type;
+			chunk_t parameters, string, lang_code;
+
+			rem_msg = (pb_remediation_parameters_msg_t*)msg;
+			parameters_type = rem_msg->get_parameters_type(rem_msg);
+			parameters = rem_msg->get_parameters(rem_msg);
+
+			if (parameters_type.vendor_id == PEN_IETF)
+			{
+				switch (parameters_type.type)
+				{
+					case PB_REMEDIATION_URI:
+						DBG1(DBG_TNC, "remediation uri: %.*s",
+									   parameters.len, parameters.ptr);
+						break;
+					case PB_REMEDIATION_STRING:
+						string = rem_msg->get_string(rem_msg, &lang_code);
+						DBG1(DBG_TNC, "remediation string: [%.*s]\n%.*s",
+									   lang_code.len, lang_code.ptr,
+									   string.len, string.ptr);
+						break;
+					default:
+						DBG1(DBG_TNC, "remediation parameters: %B", &parameters);
+				}
+			}
+			else
+			{
+				DBG1(DBG_TNC, "remediation parameters: %B", &parameters);
+			}
+			break;
+		}
+		case PB_MSG_ERROR:
+			tnccs_20_handle_ietf_error_msg(msg, &this->fatal_error);
+			break;
+		case PB_MSG_REASON_STRING:
+		{
+			pb_reason_string_msg_t *reason_msg;
+			chunk_t reason_string, language_code;
+
+			reason_msg = (pb_reason_string_msg_t*)msg;
+			reason_string = reason_msg->get_reason_string(reason_msg);
+			language_code = reason_msg->get_language_code(reason_msg);
+			DBG1(DBG_TNC, "reason string is '%.*s' [%.*s]",
+				 (int)reason_string.len, reason_string.ptr,
+				 (int)language_code.len, language_code.ptr);
+			break;
+		}
+		default:
+			break;
+	}
+}
+
+/**
+ * Handle a single PB-TNC TCG standard message according to its type
+ */
+static void handle_tcg_message(private_tnccs_20_client_t *this, pb_tnc_msg_t *msg)
+{
+	pen_type_t msg_type = msg->get_type(msg);
+
+	switch (msg_type.type)
+	{
+		case PB_TCG_MSG_PDP_REFERRAL:
+		{
+			pb_pdp_referral_msg_t *pdp_msg;
+			pen_type_t pdp_id_type;
+			u_int8_t pdp_protocol;
+
+			pdp_msg = (pb_pdp_referral_msg_t*)msg;
+			pdp_id_type = pdp_msg->get_identifier_type(pdp_msg);
+
+			if (pdp_id_type.vendor_id == PEN_TCG &&
+				pdp_id_type.type == PB_PDP_ID_FQDN)
+			{
+				this->pdp_server = chunk_clone(pdp_msg->get_fqdn(pdp_msg,
+										 &pdp_protocol, &this->pdp_port));
+				if (pdp_protocol != 0)
+				{
+					DBG1(DBG_TNC, "unsupported PDP transport protocol");
+					break;
+				}
+				DBG1(DBG_TNC, "PDP server '%.*s' is listening on port %u",
+							   this->pdp_server.len, this->pdp_server.ptr,
+							   this->pdp_port);
+			}
+			break;
+		}
+		default:
+			break;
+	}
+}
+
+/**
+ * Handle a single PB-TNC message according to its type
+ */
+static void handle_message(private_tnccs_20_client_t *this, pb_tnc_msg_t *msg)
+{
+	pen_type_t msg_type = msg->get_type(msg);
+
+	switch (msg_type.vendor_id)
+	{
+		case PEN_IETF:
+			handle_ietf_message(this, msg);
+			break;
+		case PEN_TCG:
+			handle_tcg_message(this, msg);
+			break;
+		default:
+			break;
+	}
+}
+
+/**
+ *  Build a CRETRY batch
+ */
+static void build_retry_batch(private_tnccs_20_client_t *this)
+{
+	if (this->batch_type == PB_BATCH_CRETRY)
+	{
+		/* retry batch has already been selected */
+		return;
+	}
+	change_batch_type(this, PB_BATCH_CRETRY);
+}
+
+METHOD(tnccs_20_handler_t, process, status_t,
+	private_tnccs_20_client_t *this, pb_tnc_batch_t *batch)
+{
+	pb_tnc_msg_t *msg;
+	pb_tnc_batch_type_t batch_type;
+	enumerator_t *enumerator;
+	status_t status;
+
+	batch_type = batch->get_type(batch);
+
+	DBG1(DBG_TNC, "processing PB-TNC %N batch for Connection ID %d",
+		 pb_tnc_batch_type_names, batch_type, this->connection_id);
+
+	status = batch->process(batch, this->state_machine);
+
+	if (status != FAILED)
+	{
+		enumerator_t *enumerator;
+		pb_tnc_msg_t *msg;
+		bool empty = TRUE;
+
+		if (batch_type == PB_BATCH_SRETRY)
+		{
+			/* Restart the measurements */
+			tnc->imcs->notify_connection_change(tnc->imcs,
+						this->connection_id, TNC_CONNECTION_STATE_HANDSHAKE);
+			this->send_msg = TRUE;
+			tnc->imcs->begin_handshake(tnc->imcs, this->connection_id);
+			this->send_msg = FALSE;
+		}
+
+		enumerator = batch->create_msg_enumerator(batch);
+		while (enumerator->enumerate(enumerator, &msg))
+		{
+			handle_message(this, msg);
+			empty = FALSE;
+		}
+		enumerator->destroy(enumerator);
+
+		/* received a CLOSE batch from PB-TNC server */
+		if (batch_type == PB_BATCH_CLOSE)
+		{
+			return empty ? SUCCESS : FAILED;
+		}
+
+ 		this->send_msg = TRUE;
+		tnc->imcs->batch_ending(tnc->imcs, this->connection_id);
+		this->send_msg = FALSE;
+	}
+
+	switch (status)
+	{
+		case FAILED:
+			this->fatal_error = TRUE;
+			this->mutex->lock(this->mutex);
+			change_batch_type(this, PB_BATCH_CLOSE);
+			this->mutex->unlock(this->mutex);
+			status = VERIFY_ERROR;
+			/* fall through to add error messages to outbound batch */
+		case VERIFY_ERROR:
+			enumerator = batch->create_error_enumerator(batch);
+			while (enumerator->enumerate(enumerator, &msg))
+			{
+				this->mutex->lock(this->mutex);
+				this->messages->insert_last(this->messages, msg->get_ref(msg));
+				this->mutex->unlock(this->mutex);
+			}
+			enumerator->destroy(enumerator);
+			break;
+		case SUCCESS:
+		default:
+			status = NEED_MORE;
+			break;
+	}
+
+	return status;
+}
+
+METHOD(tnccs_20_handler_t, build, status_t,
+	private_tnccs_20_client_t *this, void *buf, size_t *buflen, size_t *msglen)
+{
+	status_t status;
+	pb_tnc_state_t state;
+
+	state = this->state_machine->get_state(this->state_machine);
+
+	if (this->fatal_error && state == PB_STATE_END)
+	{
+		DBG1(DBG_TNC, "a fatal PB-TNC error occurred, terminating connection");
+		return FAILED;
+	}
+
+	/* Do not allow any asynchronous IMCs to add additional messages */
+	this->mutex->lock(this->mutex);
+
+	if (this->request_handshake_retry)
+	{
+		if (state != PB_STATE_INIT)
+		{
+			build_retry_batch(this);
+		}
+
+		/* Reset the flag for the next handshake retry request */
+		this->request_handshake_retry = FALSE;
+	}
+
+	if (this->batch_type == PB_BATCH_NONE)
+	{
+		switch (state)
+		{
+			case PB_STATE_CLIENT_WORKING:
+				DBG2(DBG_TNC, "no client data to send, "
+							  "sending empty PB-TNC CDATA batch");
+				this->batch_type = PB_BATCH_CDATA;
+				break;
+			case PB_STATE_DECIDED:
+				/**
+				 * In the DECIDED state and if no CRETRY is under way,
+				 * a PB-TNC client replies with an empty CLOSE batch.
+				 */
+				this->batch_type = PB_BATCH_CLOSE;
+				break;
+			default:
+				break;
+		}
+	}
+
+	if (this->batch_type != PB_BATCH_NONE)
+	{
+		pb_tnc_batch_t *batch;
+		pb_tnc_msg_t *msg;
+		chunk_t data;
+		int msg_count;
+		enumerator_t *enumerator;
+
+		if (this->state_machine->send_batch(this->state_machine, this->batch_type))
+		{
+			batch = pb_tnc_batch_create(FALSE, this->batch_type,
+										min(this->max_batch_len, *buflen));
+
+			enumerator = this->messages->create_enumerator(this->messages);
+			while (enumerator->enumerate(enumerator, &msg))
+			{
+				if (batch->add_msg(batch, msg))
+				{
+					this->messages->remove_at(this->messages, enumerator);
+				}
+				else
+				{
+					break;
+				}
+			}
+			enumerator->destroy(enumerator);
+
+			batch->build(batch);
+			data = batch->get_encoding(batch);
+			DBG1(DBG_TNC, "sending PB-TNC %N batch (%d bytes) for Connection ID %u",
+						   pb_tnc_batch_type_names, this->batch_type, data.len,
+						   this->connection_id);
+			DBG3(DBG_TNC, "%B", &data);
+
+			*buflen = data.len;
+			*msglen = 0;
+			memcpy(buf, data.ptr, *buflen);
+			batch->destroy(batch);
+
+			msg_count = this->messages->get_count(this->messages);
+			if (msg_count)
+			{
+				DBG2(DBG_TNC, "queued %d PB-TNC message%s for next %N batch",
+					 msg_count, (msg_count == 1) ? "" : "s",
+					 pb_tnc_batch_type_names, this->batch_type);
+			}
+			else
+			{
+				this->batch_type = PB_BATCH_NONE;
+			}
+
+			status = ALREADY_DONE;
+		}
+		else
+		{
+			change_batch_type(this, PB_BATCH_NONE);
+			status = INVALID_STATE;
+		}
+	}
+	else
+	{
+		DBG1(DBG_TNC, "no PB-TNC batch to send");
+		status = INVALID_STATE;
+	}
+	this->mutex->unlock(this->mutex);
+
+	return status;
+}
+
+METHOD(tnccs_20_handler_t, begin_handshake, void,
+	private_tnccs_20_client_t *this)
+{
+	pb_tnc_msg_t *msg;
+	char *pref_lang;
+
+	tnc->imcs->notify_connection_change(tnc->imcs, this->connection_id,
+										TNC_CONNECTION_STATE_HANDSHAKE);
+
+	/* Create PB-TNC Language Preference message */
+	pref_lang = tnc->imcs->get_preferred_language(tnc->imcs);
+	msg = pb_language_preference_msg_create(chunk_create(pref_lang,
+												strlen(pref_lang)));
+	this->mutex->lock(this->mutex);
+	this->messages->insert_last(this->messages, msg);
+	this->mutex->unlock(this->mutex);
+
+	this->send_msg = TRUE;
+	tnc->imcs->begin_handshake(tnc->imcs, this->connection_id);
+	this->send_msg = FALSE;
+}
+
+METHOD(tnccs_20_handler_t, get_send_flag, bool,
+	private_tnccs_20_client_t *this)
+{
+	return this->send_msg;
+}
+
+METHOD(tnccs_20_handler_t, add_msg, void,
+	private_tnccs_20_client_t *this, pb_tnc_msg_t *msg)
+{
+	/* adding PA message to CDATA batch only */
+	this->mutex->lock(this->mutex);
+	if (this->batch_type == PB_BATCH_NONE)
+	{
+		this->batch_type = PB_BATCH_CDATA;
+	}
+	if (this->batch_type == PB_BATCH_CDATA)
+	{
+		this->messages->insert_last(this->messages, msg);
+	}
+	else
+	{
+		msg->destroy(msg);
+	}
+	this->mutex->unlock(this->mutex);
+}
+
+METHOD(tnccs_20_handler_t, handle_errors, void,
+	private_tnccs_20_client_t *this, pb_tnc_batch_t *batch)
+{
+	pb_tnc_msg_t *msg;
+	enumerator_t *enumerator;
+
+	enumerator = batch->create_error_enumerator(batch);
+	while (enumerator->enumerate(enumerator, &msg))
+	{
+		this->mutex->lock(this->mutex);
+		this->messages->insert_last(this->messages, msg->get_ref(msg));
+		this->mutex->unlock(this->mutex);
+	}
+	enumerator->destroy(enumerator);
+}
+
+METHOD(tnccs_20_handler_t, destroy, void,
+	private_tnccs_20_client_t *this)
+{
+	if (this->connection_id)
+	{
+		tnc->tnccs->remove_connection(tnc->tnccs, this->connection_id, FALSE);
+	}
+	this->state_machine->destroy(this->state_machine);
+	this->mutex->destroy(this->mutex);
+	this->messages->destroy_offset(this->messages,
+								   offsetof(pb_tnc_msg_t, destroy));
+	free(this->pdp_server.ptr);
+	free(this);
+}
+
+METHOD(tnccs_20_client_t, get_pdp_server, chunk_t,
+	private_tnccs_20_client_t *this, u_int16_t *port)
+{
+	*port = this->pdp_port;
+
+	return this->pdp_server;
+}
+
+/**
+ * See header
+ */
+tnccs_20_handler_t* tnccs_20_client_create(tnccs_t *tnccs,
+										   tnccs_send_message_t send_msg,
+										   size_t max_batch_len,
+										   size_t max_msg_len)
+{
+	private_tnccs_20_client_t *this;
+
+	INIT(this,
+		.public = {
+			.handler = {
+				.process = _process,
+				.build = _build,
+				.begin_handshake = _begin_handshake,
+				.get_send_flag = _get_send_flag,
+				.add_msg = _add_msg,
+				.handle_errors = _handle_errors,
+				.destroy = _destroy,
+			},
+			.get_pdp_server = _get_pdp_server,
+		},
+		.state_machine = pb_tnc_state_machine_create(FALSE),
+		.mutex = mutex_create(MUTEX_TYPE_DEFAULT),
+		.messages = linked_list_create(),
+		.batch_type = PB_BATCH_CDATA,
+		.max_batch_len = max_batch_len,
+	);
+
+	this->connection_id = tnc->tnccs->create_connection(tnc->tnccs,
+											TNCCS_2_0, tnccs, send_msg,
+											&this->request_handshake_retry,
+											max_msg_len, NULL);
+	if (!this->connection_id)
+	{
+		destroy(this);
+		return NULL;
+	}
+	tnc->imcs->notify_connection_change(tnc->imcs, this->connection_id,
+										TNC_CONNECTION_STATE_CREATE);
+
+	return &this->public.handler;
+}
diff --git a/src/libtnccs/plugins/tnccs_20/tnccs_20_client.h b/src/libtnccs/plugins/tnccs_20/tnccs_20_client.h
new file mode 100644
index 000000000..daabd4e7e
--- /dev/null
+++ b/src/libtnccs/plugins/tnccs_20/tnccs_20_client.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2015 Andreas Steffen
+ * HSR Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup tnccs_20_client_h tnccs_20_client
+ * @{ @ingroup tnccs_20_client
+ */
+
+#ifndef TNCCS_20_CLIENT_H_
+#define TNCCS_20_CLIENT_H_
+
+#include <library.h>
+
+#include <tnc/tnccs/tnccs.h>
+
+#include "tnccs_20_handler.h"
+
+typedef struct tnccs_20_client_t tnccs_20_client_t;
+
+/**
+ * Interface for a TNC client
+ */
+struct tnccs_20_client_t {
+
+	/**
+	 * IF-TNCCS 2.0 protocol handler interface
+	 */
+	tnccs_20_handler_t handler;
+
+	/**
+	 * Get PDP server information if available
+	 *
+	 * @param port			PT-TLS port of the PDP server
+	 * @return				FQDN of PDP server
+	 */
+	chunk_t (*get_pdp_server)(tnccs_20_client_t *this, u_int16_t *port);
+
+};
+
+/**
+ * Create an instance of the TNC IF-TNCCS 2.0 client-side protocol handler.
+ *
+ * @param tnccs				TNC IF-TNCCS 2.0 stack
+ * @param send_msg			TNF IF-TNCCS 2.0 send message callback function
+ * @param max_batch_len		Maximum PB-TNC batch size
+ * @param max_msg_len		Maximum PA-TNC message size
+ */
+tnccs_20_handler_t* tnccs_20_client_create(tnccs_t *tnccs,
+										   tnccs_send_message_t send_msg,
+										   size_t max_batch_len,
+										   size_t max_msg_len);
+
+#endif /** TNCCS_20_CLIENT_H_ @}*/
diff --git a/src/libtnccs/plugins/tnccs_20/tnccs_20_handler.h b/src/libtnccs/plugins/tnccs_20/tnccs_20_handler.h
new file mode 100644
index 000000000..9eb642108
--- /dev/null
+++ b/src/libtnccs/plugins/tnccs_20/tnccs_20_handler.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2015 Andreas Steffen
+ * HSR Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup tnccs_20_handler_h tnccs_20_handler
+ * @{ @ingroup tnccs_20_handler
+ */
+
+#ifndef TNCCS_20_HANDLER_H_
+#define TNCCS_20_HANDLER_H_
+
+#include <library.h>
+
+#include "batch/pb_tnc_batch.h"
+#include "messages/pb_tnc_msg.h"
+
+typedef struct tnccs_20_handler_t tnccs_20_handler_t;
+
+/**
+ * Interface for an IF-TNCCS 2.0 protocol handler
+ */
+struct tnccs_20_handler_t {
+
+	/**
+	 * Process content of received PB-TNC batch
+	 *
+	 * @param batch			PB-TNC batch to be processed
+	 * @return				status
+	 */
+	status_t (*process)(tnccs_20_handler_t *this, pb_tnc_batch_t *batch);
+
+	/**
+	 * Build PB-TNC batch to be sent
+	 *
+	 * @param buf			buffer to write PB-TNC batch to
+	 * @param buflen		size of buffer, receives bytes written
+	 * @param msglen		receives size of all PB-TNCH batch
+	 * @return				status
+	 */
+	status_t (*build)(tnccs_20_handler_t *this, void *buf, size_t *buflen,
+														  size_t *msglen);
+
+	/**
+	 * Put the IMCs or IMVs into the handshake state
+	 */
+	void (*begin_handshake)(tnccs_20_handler_t *this);
+
+	/**
+	 * Indicates if IMCs or IMVs are allowed to send PA-TNC messages
+	 *
+	 * @return				TRUE if allowed to send
+	 */
+	bool (*get_send_flag)(tnccs_20_handler_t *this);
+
+	/**
+	 * Add a PB-PA message to the handler's message queue
+	 *
+	 * @param msg			PB-PA message to be added
+	 */
+	void (*add_msg)(tnccs_20_handler_t *this, pb_tnc_msg_t *msg);
+
+	/**
+	 * Handle errors that occurred during PB-TNC batch header processing
+	 *
+	 * @param batch			batch where a fatal error occured
+	 */
+	void (*handle_errors)(tnccs_20_handler_t *this, pb_tnc_batch_t *batch);
+
+	/**
+	 * Destroys a tnccs_20_handler_t object.
+	 */
+	void (*destroy)(tnccs_20_handler_t *this);
+};
+
+#endif /** TNCCS_20_HANDLER_H_ @}*/
diff --git a/src/libtnccs/plugins/tnccs_20/tnccs_20_server.c b/src/libtnccs/plugins/tnccs_20/tnccs_20_server.c
new file mode 100644
index 000000000..90131b32a
--- /dev/null
+++ b/src/libtnccs/plugins/tnccs_20/tnccs_20_server.c
@@ -0,0 +1,640 @@
+/*
+ * Copyright (C) 2015 Andreas Steffen
+ * HSR Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "tnccs_20_server.h"
+#include "messages/pb_tnc_msg.h"
+#include "messages/ietf/pb_pa_msg.h"
+#include "messages/ietf/pb_error_msg.h"
+#include "messages/ietf/pb_assessment_result_msg.h"
+#include "messages/ietf/pb_access_recommendation_msg.h"
+#include "messages/ietf/pb_remediation_parameters_msg.h"
+#include "messages/ietf/pb_reason_string_msg.h"
+#include "messages/ietf/pb_language_preference_msg.h"
+#include "messages/tcg/pb_pdp_referral_msg.h"
+#include "state_machine/pb_tnc_state_machine.h"
+
+#include <tncif_names.h>
+#include <tncif_pa_subtypes.h>
+
+#include <tnc/tnc.h>
+#include <tnc/tnccs/tnccs_manager.h>
+#include <tnc/imv/imv_manager.h>
+
+#include <threading/mutex.h>
+#include <utils/debug.h>
+#include <collections/linked_list.h>
+#include <pen/pen.h>
+
+typedef struct private_tnccs_20_server_t private_tnccs_20_server_t;
+
+/**
+ * Private data of a tnccs_20_server_t object.
+ */
+struct private_tnccs_20_server_t {
+
+	/**
+	 * Public tnccs_20_server_t interface.
+	 */
+	tnccs_20_server_t public;
+
+	/**
+	 * PB-TNC State Machine
+	 */
+	pb_tnc_state_machine_t *state_machine;
+
+	/**
+	 * Connection ID assigned to this TNCCS connection
+	 */
+	TNC_ConnectionID connection_id;
+
+	/**
+	 * PB-TNC messages to be sent
+	 */
+	linked_list_t *messages;
+
+	/**
+	 * Type of PB-TNC batch being constructed
+	 */
+	pb_tnc_batch_type_t batch_type;
+
+	/**
+	 * Maximum PB-TNC batch size
+	 */
+	size_t max_batch_len;
+
+	/**
+	 * Mutex locking the batch in construction
+	 */
+	mutex_t *mutex;
+
+	/**
+	 * Flag set while processing
+	 */
+	bool fatal_error;
+
+	/**
+	 * Flag set by IMC/IMV RequestHandshakeRetry() function
+	 */
+	bool request_handshake_retry;
+
+	/**
+	  * SendMessage() by IMV only allowed if flag is set
+	  */
+	bool send_msg;
+
+	/**
+	 * Set of IMV recommendations
+	 */
+	recommendations_t *recs;
+
+	/**
+	 *  TNC IF-T transport protocol for EAP methods
+	 */
+	bool eap_transport;
+
+	/**
+	 * PDP server FQDN
+	 */
+	chunk_t pdp_server;
+
+	/**
+	 * PDP server port
+	 */
+	u_int16_t pdp_port;
+
+};
+
+
+extern void tnccs_20_handle_ietf_error_msg(pb_tnc_msg_t *msg, bool *fatal_error);
+
+/**
+ * If the batch type changes then delete all accumulated PB-TNC messages
+ */
+static void change_batch_type(private_tnccs_20_server_t *this,
+							  pb_tnc_batch_type_t batch_type)
+{
+	pb_tnc_msg_t *msg;
+
+	if (batch_type != this->batch_type)
+	{
+		if (this->batch_type != PB_BATCH_NONE)
+		{
+			DBG1(DBG_TNC, "cancelling PB-TNC %N batch",
+				 pb_tnc_batch_type_names, this->batch_type);
+
+			while (this->messages->remove_last(this->messages,
+											  (void**)&msg) == SUCCESS)
+			{
+				msg->destroy(msg);
+			}
+		}
+		this->batch_type = batch_type;
+	}
+}
+
+/**
+ * Handle a single PB-TNC IETF standard message according to its type
+ */
+static void handle_ietf_message(private_tnccs_20_server_t *this, pb_tnc_msg_t *msg)
+{
+	pen_type_t msg_type = msg->get_type(msg);
+
+	switch (msg_type.type)
+	{
+		case PB_MSG_EXPERIMENTAL:
+			/* nothing to do */
+			break;
+		case PB_MSG_PA:
+		{
+			pb_pa_msg_t *pa_msg;
+			pen_type_t msg_subtype;
+			u_int16_t imc_id, imv_id;
+			chunk_t msg_body;
+			bool excl;
+			enum_name_t *pa_subtype_names;
+
+			pa_msg = (pb_pa_msg_t*)msg;
+			msg_subtype = pa_msg->get_subtype(pa_msg);
+			msg_body = pa_msg->get_body(pa_msg);
+			imc_id = pa_msg->get_collector_id(pa_msg);
+			imv_id = pa_msg->get_validator_id(pa_msg);
+			excl = pa_msg->get_exclusive_flag(pa_msg);
+
+			pa_subtype_names = get_pa_subtype_names(msg_subtype.vendor_id);
+			if (pa_subtype_names)
+			{
+				DBG2(DBG_TNC, "handling PB-PA message type '%N/%N' 0x%06x/0x%08x",
+					 pen_names, msg_subtype.vendor_id, pa_subtype_names,
+					 msg_subtype.type, msg_subtype.vendor_id, msg_subtype.type);
+			}
+			else
+			{
+				DBG2(DBG_TNC, "handling PB-PA message type '%N' 0x%06x/0x%08x",
+					 pen_names, msg_subtype.vendor_id, msg_subtype.vendor_id,
+					 msg_subtype.type);
+			}
+			this->send_msg = TRUE;
+			tnc->imvs->receive_message(tnc->imvs, this->connection_id,
+									   excl, msg_body.ptr, msg_body.len,
+									   msg_subtype.vendor_id,
+									   msg_subtype.type, imc_id, imv_id);
+			this->send_msg = FALSE;
+			break;
+		}
+		case PB_MSG_ERROR:
+			tnccs_20_handle_ietf_error_msg(msg, &this->fatal_error);
+			break;
+		case PB_MSG_LANGUAGE_PREFERENCE:
+		{
+			pb_language_preference_msg_t *lang_msg;
+			chunk_t lang;
+
+			lang_msg = (pb_language_preference_msg_t*)msg;
+			lang = lang_msg->get_language_preference(lang_msg);
+			DBG2(DBG_TNC, "setting language preference to '%.*s'",
+				 (int)lang.len, lang.ptr);
+			this->recs->set_preferred_language(this->recs, lang);
+			break;
+		}
+		default:
+			break;
+	}
+}
+
+/**
+ * Handle a single PB-TNC message according to its type
+ */
+static void handle_message(private_tnccs_20_server_t *this, pb_tnc_msg_t *msg)
+{
+	pen_type_t msg_type = msg->get_type(msg);
+
+	switch (msg_type.vendor_id)
+	{
+		case PEN_IETF:
+			handle_ietf_message(this, msg);
+			break;
+		default:
+			break;
+	}
+}
+
+/**
+ *  Build an SRETRY batch
+ */
+static void build_retry_batch(private_tnccs_20_server_t *this)
+{
+	if (this->batch_type == PB_BATCH_SRETRY)
+	{
+		/* retry batch has already been selected */
+		return;
+	}
+	change_batch_type(this, PB_BATCH_SRETRY);
+
+	this->recs->clear_recommendation(this->recs);
+	tnc->imvs->notify_connection_change(tnc->imvs, this->connection_id,
+										TNC_CONNECTION_STATE_HANDSHAKE);
+}
+
+METHOD(tnccs_20_handler_t, process, status_t,
+	private_tnccs_20_server_t *this, pb_tnc_batch_t *batch)
+{
+	pb_tnc_msg_t *msg;
+	pb_tnc_batch_type_t batch_type;
+	enumerator_t *enumerator;
+	status_t status;
+
+	batch_type = batch->get_type(batch);
+
+	DBG1(DBG_TNC, "processing PB-TNC %N batch for Connection ID %d",
+		 pb_tnc_batch_type_names, batch_type, this->connection_id);
+
+	status = batch->process(batch, this->state_machine);
+	DBG2(DBG_TNC, "status after batch process: %N", status_names, status);
+
+	if (status != FAILED)
+	{
+		enumerator_t *enumerator;
+		pb_tnc_msg_t *msg;
+		bool empty = TRUE;
+
+		if (batch_type == PB_BATCH_CRETRY)
+		{
+			/* Send an SRETRY batch in response */
+			this->mutex->lock(this->mutex);
+			build_retry_batch(this);
+			this->mutex->unlock(this->mutex);
+		}
+
+		enumerator = batch->create_msg_enumerator(batch);
+		while (enumerator->enumerate(enumerator, &msg))
+		{
+			handle_message(this, msg);
+			empty = FALSE;
+		}
+		enumerator->destroy(enumerator);
+
+		/* received a CLOSE batch from PB-TNC client */
+		if (batch_type == PB_BATCH_CLOSE)
+		{
+			return empty ? SUCCESS : FAILED;
+		}
+
+		this->send_msg = TRUE;
+		tnc->imvs->batch_ending(tnc->imvs, this->connection_id);
+		this->send_msg = FALSE;
+	}
+
+	switch (status)
+	{
+		case FAILED:
+			this->fatal_error = TRUE;
+			this->mutex->lock(this->mutex);
+			change_batch_type(this, PB_BATCH_CLOSE);
+			this->mutex->unlock(this->mutex);
+			status = VERIFY_ERROR;
+			/* fall through to add error messages to outbound batch */
+		case VERIFY_ERROR:
+			enumerator = batch->create_error_enumerator(batch);
+			while (enumerator->enumerate(enumerator, &msg))
+			{
+				this->mutex->lock(this->mutex);
+				this->messages->insert_last(this->messages, msg->get_ref(msg));
+				this->mutex->unlock(this->mutex);
+			}
+			enumerator->destroy(enumerator);
+			break;
+		case SUCCESS:
+		default:
+			status = NEED_MORE;
+			break;
+	}
+
+	return status;
+}
+
+/**
+ *  Build a RESULT batch if a final recommendation is available
+ */
+static void check_and_build_recommendation(private_tnccs_20_server_t *this)
+{
+	TNC_IMV_Action_Recommendation rec;
+	TNC_IMV_Evaluation_Result eval;
+	TNC_ConnectionState state;
+	TNC_IMVID id;
+	chunk_t reason, language;
+	enumerator_t *enumerator;
+	pb_tnc_msg_t *msg;
+	pb_access_recommendation_code_t pb_rec;
+
+	if (!this->recs->have_recommendation(this->recs, &rec, &eval))
+	{
+		tnc->imvs->solicit_recommendation(tnc->imvs, this->connection_id);
+	}
+	if (this->recs->have_recommendation(this->recs, &rec, &eval))
+	{
+		this->batch_type = PB_BATCH_RESULT;
+
+		msg = pb_assessment_result_msg_create(eval);
+		this->messages->insert_last(this->messages, msg);
+
+		/**
+		 * Map IMV Action Recommendation codes to PB Access Recommendation codes
+		 * and communicate Access Recommendation to IMVs
+		 */
+		switch (rec)
+		{
+			case TNC_IMV_ACTION_RECOMMENDATION_ALLOW:
+				state = TNC_CONNECTION_STATE_ACCESS_ALLOWED;
+				pb_rec = PB_REC_ACCESS_ALLOWED;
+				break;
+			case TNC_IMV_ACTION_RECOMMENDATION_ISOLATE:
+				state = TNC_CONNECTION_STATE_ACCESS_ISOLATED;
+				pb_rec = PB_REC_QUARANTINED;
+				break;
+			case TNC_IMV_ACTION_RECOMMENDATION_NO_ACCESS:
+			case TNC_IMV_ACTION_RECOMMENDATION_NO_RECOMMENDATION:
+			default:
+				state = TNC_CONNECTION_STATE_ACCESS_NONE;
+				pb_rec = PB_REC_ACCESS_DENIED;
+		}
+		tnc->imvs->notify_connection_change(tnc->imvs, this->connection_id,
+											state);
+
+		msg = pb_access_recommendation_msg_create(pb_rec);
+		this->messages->insert_last(this->messages, msg);
+
+		enumerator = this->recs->create_reason_enumerator(this->recs);
+		while (enumerator->enumerate(enumerator, &id, &reason, &language))
+		{
+			msg = pb_reason_string_msg_create(reason, language);
+			this->messages->insert_last(this->messages, msg);
+		}
+		enumerator->destroy(enumerator);
+	}
+}
+
+METHOD(tnccs_20_handler_t, build, status_t,
+	private_tnccs_20_server_t *this, void *buf, size_t *buflen, size_t *msglen)
+{
+	status_t status;
+	pb_tnc_state_t state;
+
+	state = this->state_machine->get_state(this->state_machine);
+
+	if (this->fatal_error && state == PB_STATE_END)
+	{
+		DBG1(DBG_TNC, "a fatal PB-TNC error occurred, terminating connection");
+		return FAILED;
+	}
+
+	/* Do not allow any asynchronous IMVs to add additional messages */
+	this->mutex->lock(this->mutex);
+
+	if (this->request_handshake_retry)
+	{
+		if (state != PB_STATE_INIT)
+		{
+			build_retry_batch(this);
+		}
+
+		/* Reset the flag for the next handshake retry request */
+		this->request_handshake_retry = FALSE;
+	}
+
+	if (state == PB_STATE_SERVER_WORKING &&
+		this->recs->have_recommendation(this->recs, NULL, NULL))
+	{
+		check_and_build_recommendation(this);
+	}
+
+	if (this->batch_type == PB_BATCH_NONE)
+	{
+		if (state == PB_STATE_SERVER_WORKING)
+		{
+			if (this->state_machine->get_empty_cdata(this->state_machine))
+			{
+				check_and_build_recommendation(this);
+			}
+			else
+			{
+				DBG2(DBG_TNC, "no recommendation available yet, "
+							  "sending empty PB-TNC SDATA batch");
+				this->batch_type = PB_BATCH_SDATA;
+			}
+		}
+	}
+
+	if (this->batch_type != PB_BATCH_NONE)
+	{
+		pb_tnc_batch_t *batch;
+		pb_tnc_msg_t *msg;
+		chunk_t data;
+		int msg_count;
+		enumerator_t *enumerator;
+
+		if (this->state_machine->send_batch(this->state_machine, this->batch_type))
+		{
+			batch = pb_tnc_batch_create(TRUE, this->batch_type,
+										min(this->max_batch_len, *buflen));
+
+			enumerator = this->messages->create_enumerator(this->messages);
+			while (enumerator->enumerate(enumerator, &msg))
+			{
+				if (batch->add_msg(batch, msg))
+				{
+					this->messages->remove_at(this->messages, enumerator);
+				}
+				else
+				{
+					break;
+				}
+			}
+			enumerator->destroy(enumerator);
+
+			batch->build(batch);
+			data = batch->get_encoding(batch);
+			DBG1(DBG_TNC, "sending PB-TNC %N batch (%d bytes) for Connection ID %u",
+						   pb_tnc_batch_type_names, this->batch_type, data.len,
+						   this->connection_id);
+			DBG3(DBG_TNC, "%B", &data);
+
+			*buflen = data.len;
+			*msglen = 0;
+			memcpy(buf, data.ptr, *buflen);
+			batch->destroy(batch);
+
+			msg_count = this->messages->get_count(this->messages);
+			if (msg_count)
+			{
+				DBG2(DBG_TNC, "queued %d PB-TNC message%s for next %N batch",
+					 msg_count, (msg_count == 1) ? "" : "s",
+					 pb_tnc_batch_type_names, this->batch_type);
+			}
+			else
+			{
+				this->batch_type = PB_BATCH_NONE;
+			}
+
+			status = ALREADY_DONE;
+		}
+		else
+		{
+			change_batch_type(this, PB_BATCH_NONE);
+			status = INVALID_STATE;
+		}
+	}
+	else
+	{
+		DBG1(DBG_TNC, "no PB-TNC batch to send");
+		status = INVALID_STATE;
+	}
+	this->mutex->unlock(this->mutex);
+
+	return status;
+}
+
+METHOD(tnccs_20_handler_t, begin_handshake, void,
+	private_tnccs_20_server_t *this)
+{
+	pb_tnc_msg_t *msg;
+	identification_t *pdp_server;
+	u_int16_t *pdp_port;
+
+	tnc->imvs->notify_connection_change(tnc->imvs, this->connection_id,
+										TNC_CONNECTION_STATE_HANDSHAKE);
+
+	/* Send a PB-TNC TCG PDP Referral message if PDP is known */
+	pdp_server = (identification_t*)lib->get(lib, "pt-tls-server");
+	pdp_port = (u_int16_t*)lib->get(lib, "pt-tls-port");
+
+	if (this->eap_transport && pdp_server && pdp_port)
+	{
+		msg = pb_pdp_referral_msg_create_from_fqdn(
+						pdp_server->get_encoding(pdp_server), *pdp_port);
+		this->mutex->lock(this->mutex);
+		this->messages->insert_last(this->messages, msg);
+		this->mutex->unlock(this->mutex);
+	}
+}
+
+METHOD(tnccs_20_handler_t, get_send_flag, bool,
+	private_tnccs_20_server_t *this)
+{
+	return this->send_msg;
+}
+
+METHOD(tnccs_20_handler_t, add_msg, void,
+	private_tnccs_20_server_t *this, pb_tnc_msg_t *msg)
+{
+	/* adding PA message to SDATA batch only */
+	this->mutex->lock(this->mutex);
+	if (this->batch_type == PB_BATCH_NONE)
+	{
+		this->batch_type = PB_BATCH_SDATA;
+	}
+	if (this->batch_type == PB_BATCH_SDATA)
+	{
+		this->messages->insert_last(this->messages, msg);
+	}
+	else
+	{
+		msg->destroy(msg);
+	}
+	this->mutex->unlock(this->mutex);
+}
+
+METHOD(tnccs_20_handler_t, handle_errors, void,
+	private_tnccs_20_server_t *this,  pb_tnc_batch_t *batch)
+{
+	pb_tnc_msg_t *msg;
+	enumerator_t *enumerator;
+
+	enumerator = batch->create_error_enumerator(batch);
+	while (enumerator->enumerate(enumerator, &msg))
+	{
+		this->mutex->lock(this->mutex);
+		this->messages->insert_last(this->messages, msg->get_ref(msg));
+		this->mutex->unlock(this->mutex);
+	}
+	enumerator->destroy(enumerator);
+}
+
+METHOD(tnccs_20_handler_t, destroy, void,
+	private_tnccs_20_server_t *this)
+{
+	if (this->connection_id)
+	{
+		tnc->tnccs->remove_connection(tnc->tnccs, this->connection_id, TRUE);
+	}
+	this->state_machine->destroy(this->state_machine);
+	this->mutex->destroy(this->mutex);
+	this->messages->destroy_offset(this->messages,
+								   offsetof(pb_tnc_msg_t, destroy));
+	free(this);
+}
+
+METHOD(tnccs_20_server_t, have_recommendation, bool,
+	private_tnccs_20_server_t *this, TNC_IMV_Action_Recommendation *rec,
+	TNC_IMV_Evaluation_Result *eval)
+{
+	return this->recs->have_recommendation(this->recs, rec, eval);
+}
+
+/**
+ * See header
+ */
+tnccs_20_handler_t* tnccs_20_server_create(tnccs_t *tnccs,
+										   tnccs_send_message_t send_msg,
+										   size_t max_batch_len,
+										   size_t max_msg_len,
+										   bool eap_transport)
+{
+	private_tnccs_20_server_t *this;
+
+	INIT(this,
+		.public = {
+			.handler = {
+				.process = _process,
+				.build = _build,
+				.begin_handshake = _begin_handshake,
+				.get_send_flag = _get_send_flag,
+				.add_msg = _add_msg,
+				.handle_errors = _handle_errors,
+				.destroy = _destroy,
+			},
+			.have_recommendation = _have_recommendation,
+		},
+		.state_machine = pb_tnc_state_machine_create(TRUE),
+		.mutex = mutex_create(MUTEX_TYPE_DEFAULT),
+		.messages = linked_list_create(),
+		.batch_type = PB_BATCH_SDATA,
+		.max_batch_len = max_batch_len,
+		.eap_transport = eap_transport,
+	);
+
+	this->connection_id = tnc->tnccs->create_connection(tnc->tnccs,
+											TNCCS_2_0, tnccs, send_msg,
+											&this->request_handshake_retry,
+											max_msg_len, &this->recs);
+	if (!this->connection_id)
+	{
+		destroy(this);
+		return NULL;
+	}
+	tnc->imvs->notify_connection_change(tnc->imvs, this->connection_id,
+										TNC_CONNECTION_STATE_CREATE);
+
+	return &this->public.handler;
+}
diff --git a/src/libtnccs/plugins/tnccs_20/tnccs_20_server.h b/src/libtnccs/plugins/tnccs_20/tnccs_20_server.h
new file mode 100644
index 000000000..5d8d56110
--- /dev/null
+++ b/src/libtnccs/plugins/tnccs_20/tnccs_20_server.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2015 Andreas Steffen
+ * HSR Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup tnccs_20_server_h tnccs_20_server
+ * @{ @ingroup tnccs_20_server
+ */
+
+#ifndef TNCCS_20_SERVER_H_
+#define TNCCS_20_SERVER_H_
+
+#include <library.h>
+
+#include <tnc/tnccs/tnccs.h>
+
+#include "tnccs_20_handler.h"
+
+typedef struct tnccs_20_server_t tnccs_20_server_t;
+
+/**
+ * Interface for a TNC server
+ */
+struct tnccs_20_server_t {
+
+	/**
+	 * IF-TNCCS 2.0 protocol handler interface
+	 */
+	tnccs_20_handler_t handler;
+
+	/**
+	 * Check if an Action Recommendation is already available
+	 *
+	 * @param rec			TNC Action Recommendation
+	 * @param eval			TNC Evaluation Result
+	 * @return				TRUE if Action Recommendation is 
+	 */
+	bool (*have_recommendation)(tnccs_20_server_t *this,
+								TNC_IMV_Action_Recommendation *rec,
+								TNC_IMV_Evaluation_Result *eval);
+
+};
+
+/**
+ * Create an instance of the TNC IF-TNCCS 2.0 server-side protocol handler.
+ *
+ * @param tnccs				TNC IF-TNCCS 2.0 stack
+ * @param send_msg			TNF IF-TNCCS 2.0 send message callback function
+ * @param max_batch_len		Maximum PB-TNC batch size
+ * @param max_msg_len		Maximum PA-TNC message size
+ * @param eap_transport		TRUE if IF-T for EAP methods
+ */
+tnccs_20_handler_t* tnccs_20_server_create(tnccs_t *tnccs, 
+										   tnccs_send_message_t send_msg,
+										   size_t max_batch_len,
+										   size_t max_msg_len,
+										   bool eap_transport);
+
+
+#endif /** TNCCS_20_SERVER_H_ @}*/