Imported Upstream version 1.1.1+rev1207upstream/1.1.1+rev1207

1 files changed, 1055 insertions, 0 deletions

diff --git a/lib/libdvben50221/en50221_session.c b/lib/libdvben50221/en50221_session.c
new file mode 100644
index 0000000..3fb9902
--- /dev/null
+++ b/lib/libdvben50221/en50221_session.c
@@ -0,0 +1,1055 @@
+/*
+    en50221 encoder An implementation for libdvb
+    an implementation for the en50221 transport layer
+
+    Copyright (C) 2004, 2005 Manu Abraham <abraham.manu@gmail.com>
+    Copyright (C) 2005 Julian Scheel (julian at jusst dot de)
+    Copyright (C) 2006 Andrew de Quincey (adq_dvb@lidskialf.net)
+
+    This library is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as
+    published by the Free Software Foundation; either version 2.1 of
+    the License, or (at your option) any later version.
+
+    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 Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+*/
+
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <time.h>
+#include <libdvbmisc/dvbmisc.h>
+#include <sys/uio.h>
+#include <pthread.h>
+#include "en50221_transport.h"
+#include "en50221_session.h"
+#include "en50221_errno.h"
+#include "asn_1.h"
+
+
+// these are the possible session statuses
+#define S_STATUS_OPEN                    0x00	// session is opened
+#define S_STATUS_CLOSE_NO_RES            0xF0	// could not open session, no proper resource available
+#define S_STATUS_CLOSE_RES_UNAVAILABLE   0xF1	// could not open session, resource unavailable
+#define S_STATUS_CLOSE_RES_LOW_VERSION   0xF2	// could not open session, resource version too low
+#define S_STATUS_CLOSE_RES_BUSY          0xF3	// could not open session, resource is busy
+
+#define ST_OPEN_SESSION_REQ     0x91	// h<--m
+#define ST_OPEN_SESSION_RES     0x92	// h-->m
+#define ST_CREATE_SESSION       0x93	// h-->m
+#define ST_CREATE_SESSION_RES   0x94	// h<--m
+#define ST_CLOSE_SESSION_REQ    0x95	// h<->m
+#define ST_CLOSE_SESSION_RES    0x96	// h<->m
+#define ST_SESSION_NUMBER       0x90	// h<->m
+
+#define S_STATE_IDLE            0x01	// this session is not in use
+#define S_STATE_ACTIVE          0x02	// this session is in use
+#define S_STATE_IN_CREATION     0x04	// this session waits for a ST_CREATE_SESSION_RES to become active
+#define S_STATE_IN_DELETION     0x08	// this session waits for ST_CLOSE_SESSION_RES to become idle again
+
+
+// for each session we store its identifier, the resource-id
+// it is linked to and the callback of the specific resource
+struct en50221_session {
+	uint8_t state;
+	uint32_t resource_id;
+	uint8_t slot_id;
+	uint8_t connection_id;
+
+	en50221_sl_resource_callback callback;
+	void *callback_arg;
+
+	pthread_mutex_t session_lock;
+};
+
+struct en50221_session_layer {
+	uint32_t max_sessions;
+	struct en50221_transport_layer *tl;
+
+	en50221_sl_lookup_callback lookup;
+	void *lookup_arg;
+
+	en50221_sl_session_callback session;
+	void *session_arg;
+
+	pthread_mutex_t global_lock;
+	pthread_mutex_t setcallback_lock;
+
+	int error;
+
+	struct en50221_session *sessions;
+};
+
+static void en50221_sl_transport_callback(void *arg, int reason,
+					  uint8_t * data,
+					  uint32_t data_length,
+					  uint8_t slot_id,
+					  uint8_t connection_id);
+static int en50221_sl_alloc_new_session(struct en50221_session_layer *sl,
+					uint32_t resource_id,
+					uint8_t slot_id,
+					uint8_t connection_id,
+					en50221_sl_resource_callback
+					callback, void *arg);
+
+
+
+
+struct en50221_session_layer *en50221_sl_create(struct en50221_transport_layer *tl,
+						uint32_t max_sessions)
+{
+	struct en50221_session_layer *sl = NULL;
+	uint32_t i;
+
+	// setup structure
+	sl = (struct en50221_session_layer *)
+	    malloc(sizeof(struct en50221_session_layer));
+	if (sl == NULL)
+		goto error_exit;
+	sl->max_sessions = max_sessions;
+	sl->lookup = NULL;
+	sl->session = NULL;
+	sl->tl = tl;
+	sl->error = 0;
+
+	// init the mutex
+	pthread_mutex_init(&sl->global_lock, NULL);
+	pthread_mutex_init(&sl->setcallback_lock, NULL);
+
+	// create the slots
+	sl->sessions = malloc(sizeof(struct en50221_session) * max_sessions);
+	if (sl->sessions == NULL)
+		goto error_exit;
+
+	// set them up
+	for (i = 0; i < max_sessions; i++) {
+		sl->sessions[i].state = S_STATE_IDLE;
+		sl->sessions[i].callback = NULL;
+
+		pthread_mutex_init(&sl->sessions[i].session_lock, NULL);
+	}
+
+	// register ourselves with the transport layer
+	en50221_tl_register_callback(tl, en50221_sl_transport_callback, sl);
+
+	return sl;
+
+error_exit:
+	en50221_sl_destroy(sl);
+	return NULL;
+}
+
+void en50221_sl_destroy(struct en50221_session_layer *sl)
+{
+	uint32_t i;
+
+	if (sl) {
+		if (sl->sessions) {
+			for (i = 0; i < sl->max_sessions; i++) {
+				pthread_mutex_destroy(&sl->sessions[i].session_lock);
+			}
+			free(sl->sessions);
+		}
+
+		pthread_mutex_destroy(&sl->setcallback_lock);
+		pthread_mutex_destroy(&sl->global_lock);
+
+		free(sl);
+	}
+}
+
+int en50221_sl_get_error(struct en50221_session_layer *sl)
+{
+	return sl->error;
+}
+
+void en50221_sl_register_lookup_callback(struct en50221_session_layer *sl,
+					 en50221_sl_lookup_callback
+					 callback, void *arg)
+{
+	pthread_mutex_lock(&sl->setcallback_lock);
+	sl->lookup = callback;
+	sl->lookup_arg = arg;
+	pthread_mutex_unlock(&sl->setcallback_lock);
+}
+
+void en50221_sl_register_session_callback(struct en50221_session_layer *sl,
+					  en50221_sl_session_callback
+					  callback, void *arg)
+{
+	pthread_mutex_lock(&sl->setcallback_lock);
+	sl->session = callback;
+	sl->session_arg = arg;
+	pthread_mutex_unlock(&sl->setcallback_lock);
+}
+
+int en50221_sl_create_session(struct en50221_session_layer *sl,
+			      int slot_id, uint8_t connection_id,
+			      uint32_t resource_id,
+			      en50221_sl_resource_callback callback,
+			      void *arg)
+{
+	// lookup next free session_id:
+	pthread_mutex_lock(&sl->global_lock);
+	int session_number =
+	    en50221_sl_alloc_new_session(sl, resource_id, slot_id,
+					 connection_id, callback, arg);
+	if (session_number == -1) {
+		pthread_mutex_unlock(&sl->global_lock);
+		return -1;
+	}
+	pthread_mutex_unlock(&sl->global_lock);
+
+	// make up the header
+	uint8_t hdr[8];
+	hdr[0] = ST_CREATE_SESSION;
+	hdr[1] = 6;
+	hdr[2] = resource_id >> 24;
+	hdr[3] = resource_id >> 16;
+	hdr[4] = resource_id >> 8;
+	hdr[5] = resource_id;
+	hdr[6] = session_number >> 8;
+	hdr[7] = session_number;
+
+	// send this command
+	if (en50221_tl_send_data(sl->tl, slot_id, connection_id, hdr, 8)) {
+		pthread_mutex_lock(&sl->sessions[session_number].session_lock);
+		if (sl->sessions[session_number].state == S_STATE_IN_CREATION) {
+			sl->sessions[session_number].state = S_STATE_IDLE;
+		}
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+
+		sl->error = en50221_tl_get_error(sl->tl);
+		return -1;
+	}
+	// ok.
+	return session_number;
+}
+
+int en50221_sl_destroy_session(struct en50221_session_layer *sl,
+			       uint16_t session_number)
+{
+	if (session_number >= sl->max_sessions) {
+		sl->error = EN50221ERR_BADSESSIONNUMBER;
+		return -1;
+	}
+
+	pthread_mutex_lock(&sl->sessions[session_number].session_lock);
+	if (!(sl->sessions[session_number].state & (S_STATE_ACTIVE | S_STATE_IN_DELETION))) {
+		sl->error = EN50221ERR_BADSESSIONNUMBER;
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return -1;
+	}
+	// set the state
+	sl->sessions[session_number].state = S_STATE_IN_DELETION;
+
+	// get essential details
+	uint8_t slot_id = sl->sessions[session_number].slot_id;
+	uint8_t connection_id = sl->sessions[session_number].connection_id;
+	pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+
+	//  sendit
+	uint8_t hdr[4];
+	hdr[0] = ST_CLOSE_SESSION_REQ;
+	hdr[1] = 2;
+	hdr[2] = session_number >> 8;
+	hdr[3] = session_number;
+	if (en50221_tl_send_data(sl->tl, slot_id, connection_id, hdr, 4)) {
+		pthread_mutex_lock(&sl->sessions[session_number].session_lock);
+		if (sl->sessions[session_number].state == S_STATE_IN_DELETION) {
+			sl->sessions[session_number].state = S_STATE_IDLE;
+		}
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+
+		sl->error = en50221_tl_get_error(sl->tl);
+		return -1;
+	}
+
+	return 0;
+}
+
+int en50221_sl_send_data(struct en50221_session_layer *sl,
+			 uint16_t session_number,
+			 uint8_t *data,
+			 uint16_t data_length)
+{
+	if (session_number >= sl->max_sessions) {
+		sl->error = EN50221ERR_BADSESSIONNUMBER;
+		return -1;
+	}
+
+	pthread_mutex_lock(&sl->sessions[session_number].session_lock);
+	if (sl->sessions[session_number].state != S_STATE_ACTIVE) {
+		sl->error = EN50221ERR_BADSESSIONNUMBER;
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return -1;
+	}
+	// get essential details
+	uint8_t slot_id = sl->sessions[session_number].slot_id;
+	uint8_t connection_id = sl->sessions[session_number].connection_id;
+	pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+
+	// sendit
+	struct iovec iov[2];
+	uint8_t hdr[4];
+	hdr[0] = ST_SESSION_NUMBER;
+	hdr[1] = 2;
+	hdr[2] = session_number >> 8;
+	hdr[3] = session_number;
+	iov[0].iov_base = hdr;
+	iov[0].iov_len = 4;
+	iov[1].iov_base = data;
+	iov[1].iov_len = data_length;
+	if (en50221_tl_send_datav(sl->tl, slot_id, connection_id, iov, 2)) {
+		sl->error = en50221_tl_get_error(sl->tl);
+		return -1;
+	}
+
+	return 0;
+}
+
+int en50221_sl_send_datav(struct en50221_session_layer *sl,
+			  uint16_t session_number,
+			  struct iovec *vector,
+			  int iov_count)
+{
+	if (session_number >= sl->max_sessions) {
+		sl->error = EN50221ERR_BADSESSIONNUMBER;
+		return -1;
+	}
+
+	pthread_mutex_lock(&sl->sessions[session_number].session_lock);
+	if (sl->sessions[session_number].state != S_STATE_ACTIVE) {
+		sl->error = EN50221ERR_BADSESSIONNUMBER;
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return -1;
+	}
+	if (iov_count > 9) {
+		sl->error = EN50221ERR_IOVLIMIT;
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return -1;
+	}
+	uint8_t slot_id = sl->sessions[session_number].slot_id;
+	uint8_t connection_id = sl->sessions[session_number].connection_id;
+	pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+
+	// make up the header
+	struct iovec out_iov[10];
+	uint8_t hdr[4];
+	hdr[0] = ST_SESSION_NUMBER;
+	hdr[1] = 2;
+	hdr[2] = session_number >> 8;
+	hdr[3] = session_number;
+	out_iov[0].iov_base = hdr;
+	out_iov[0].iov_len = 4;
+
+	// make up the data
+	memcpy(&out_iov[1], vector, iov_count * sizeof(struct iovec));
+
+	// send this command
+	if (en50221_tl_send_datav(sl->tl, slot_id, connection_id, out_iov, iov_count + 1)) {
+		sl->error = en50221_tl_get_error(sl->tl);
+		return -1;
+	}
+	return 0;
+}
+
+int en50221_sl_broadcast_data(struct en50221_session_layer *sl,
+			      int slot_id, uint32_t resource_id,
+			      uint8_t *data, uint16_t data_length)
+{
+	uint32_t i;
+
+	for (i = 0; i < sl->max_sessions; i++) {
+		pthread_mutex_lock(&sl->sessions[i].session_lock);
+
+		if (sl->sessions[i].state != S_STATE_ACTIVE) {
+			pthread_mutex_unlock(&sl->sessions[i].session_lock);
+			continue;
+		}
+		if ((slot_id != -1)
+		    && (slot_id != sl->sessions[i].slot_id)) {
+			pthread_mutex_unlock(&sl->sessions[i].session_lock);
+			continue;
+		}
+
+		if (sl->sessions[i].resource_id == resource_id) {
+			pthread_mutex_unlock(&sl->sessions[i].session_lock);
+			en50221_sl_send_data(sl, i, data, data_length);
+		} else {
+			pthread_mutex_unlock(&sl->sessions[i].session_lock);
+		}
+	}
+
+	return 0;
+}
+
+
+
+static void en50221_sl_handle_open_session_request(struct en50221_session_layer *sl,
+						   uint8_t *data,
+						   uint32_t data_length,
+						   uint8_t slot_id,
+						   uint8_t connection_id)
+{
+	// check
+	if (data_length < 5) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %02x\n",
+		      slot_id);
+		return;
+	}
+	if (data[0] != 4) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %02x\n",
+		      slot_id);
+		return;
+	}
+	// get the resource id
+	uint32_t requested_resource_id =
+	    (data[1] << 24) | (data[2] << 16) | (data[3] << 8) | data[4];
+
+	// get lookup callback details
+	pthread_mutex_lock(&sl->setcallback_lock);
+	en50221_sl_lookup_callback lcb = sl->lookup;
+	void *lcb_arg = sl->lookup_arg;
+	pthread_mutex_unlock(&sl->setcallback_lock);
+
+	// first of all, lookup this resource id
+	int status = S_STATUS_CLOSE_NO_RES;
+	en50221_sl_resource_callback resource_callback = NULL;
+	void *resource_arg = NULL;
+	uint32_t connected_resource_id;
+	if (lcb) {
+		status =
+		    lcb(lcb_arg, slot_id, requested_resource_id,
+			&resource_callback, &resource_arg,
+			&connected_resource_id);
+		switch (status) {
+		case 0:
+			status = S_STATUS_OPEN;
+			break;
+
+		case -1:
+			status = S_STATUS_CLOSE_NO_RES;
+			break;
+
+		case -2:
+			status = S_STATUS_CLOSE_RES_LOW_VERSION;
+			break;
+
+		case -3:
+			status = S_STATUS_CLOSE_RES_UNAVAILABLE;
+			break;
+		}
+	}
+	// if we found it, get a new session for it
+	int session_number = -1;
+	if (status == S_STATUS_OPEN) {
+		// lookup next free session_id:
+		pthread_mutex_lock(&sl->global_lock);
+		session_number =
+		    en50221_sl_alloc_new_session(sl, connected_resource_id,
+						 slot_id, connection_id,
+						 resource_callback,
+						 resource_arg);
+		pthread_mutex_unlock(&sl->global_lock);
+
+		if (session_number == -1) {
+			status = S_STATUS_CLOSE_NO_RES;
+		} else {
+			// inform upper layers/ check availability
+			pthread_mutex_lock(&sl->setcallback_lock);
+			en50221_sl_session_callback cb = sl->session;
+			void *cb_arg = sl->session_arg;
+			pthread_mutex_unlock(&sl->setcallback_lock);
+			if (cb) {
+				if (cb(cb_arg, S_SCALLBACK_REASON_CAMCONNECTING,
+				       slot_id, session_number,
+				       connected_resource_id)) {
+					status = S_STATUS_CLOSE_RES_BUSY;
+				}
+			} else {
+				status = S_STATUS_CLOSE_RES_UNAVAILABLE;
+			}
+		}
+	}
+	// send response
+	uint8_t hdr[9];
+	hdr[0] = ST_OPEN_SESSION_RES;
+	hdr[1] = 7;
+	hdr[2] = status;
+	hdr[3] = connected_resource_id >> 24;
+	hdr[4] = connected_resource_id >> 16;
+	hdr[5] = connected_resource_id >> 8;
+	hdr[6] = connected_resource_id;
+	hdr[7] = session_number >> 8;
+	hdr[8] = session_number;
+	if (en50221_tl_send_data(sl->tl, slot_id, connection_id, hdr, 9)) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Transport layer error %i occurred\n",
+		      en50221_tl_get_error(sl->tl));
+		status = S_STATUS_CLOSE_NO_RES;
+		// fallthrough
+	}
+	// inform upper layers what happened
+	if (session_number != -1) {
+		// setup session state apppropriately from upper layer response
+		pthread_mutex_lock(&sl->sessions[session_number].session_lock);
+		if (status != S_STATUS_OPEN) {
+			sl->sessions[session_number].state = S_STATE_IDLE;
+		} else {
+			sl->sessions[session_number].state = S_STATE_ACTIVE;
+		}
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+
+		// tell upper layers
+		if (sl->sessions[session_number].state == S_STATE_ACTIVE) {
+			pthread_mutex_lock(&sl->setcallback_lock);
+			en50221_sl_session_callback cb = sl->session;
+			void *cb_arg = sl->session_arg;
+			pthread_mutex_unlock(&sl->setcallback_lock);
+
+			if (status == S_STATUS_OPEN) {
+				if (cb)
+					cb(cb_arg,
+					   S_SCALLBACK_REASON_CAMCONNECTED,
+					   slot_id, session_number,
+					   connected_resource_id);
+			} else {
+				sl->sessions[session_number].state =
+				    S_STATE_IDLE;
+				if (cb)
+					cb(cb_arg,
+					   S_SCALLBACK_REASON_CAMCONNECTFAIL,
+					   slot_id, session_number,
+					   connected_resource_id);
+			}
+		}
+	}
+}
+
+static void en50221_sl_handle_close_session_request(struct en50221_session_layer *sl,
+						    uint8_t * data,
+						    uint32_t data_length,
+						    uint8_t slot_id,
+						    uint8_t connection_id)
+{
+	// check
+	if (data_length < 3) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %02x\n",
+		      slot_id);
+		return;
+	}
+	if (data[0] != 2) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %02x\n",
+		      slot_id);
+		return;
+	}
+	// extract session number
+	uint16_t session_number = (data[1] << 8) | data[2];
+
+	// check session number is ok
+	uint8_t code = 0x00;
+	uint32_t resource_id = 0;
+	if (session_number >= sl->max_sessions) {
+		code = 0xF0;	// session close error
+		print(LOG_LEVEL, ERROR, 1, "Received bad session id %i\n",
+		      slot_id);
+	} else {
+		pthread_mutex_lock(&sl->sessions[session_number].
+				   session_lock);
+		if (slot_id != sl->sessions[session_number].slot_id) {
+			print(LOG_LEVEL, ERROR, 1,
+			      "Received unexpected session on invalid slot %i\n",
+			      slot_id);
+			code = 0xF0;	// session close error
+		}
+		if (connection_id != sl->sessions[session_number].connection_id) {
+			print(LOG_LEVEL, ERROR, 1,
+			      "Received unexpected session on invalid slot %i\n",
+			      slot_id);
+			code = 0xF0;	// session close error
+		}
+		if (!(sl->sessions[session_number].state & (S_STATE_ACTIVE | S_STATE_IN_DELETION))) {
+			print(LOG_LEVEL, ERROR, 1,
+			      "Received unexpected session on invalid slot %i\n",
+			      slot_id);
+			code = 0xF0;	// session close error
+		}
+
+		if (code == 0x00) {
+			sl->sessions[session_number].state = S_STATE_IDLE;
+			code = 0x00;	// close ok
+		}
+		resource_id = sl->sessions[session_number].resource_id;
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+	}
+
+	// make up the response
+	uint8_t hdr[5];
+	hdr[0] = ST_CLOSE_SESSION_RES;
+	hdr[1] = 3;
+	hdr[2] = code;
+	hdr[3] = session_number >> 8;
+	hdr[4] = session_number;
+
+	// sendit
+	if (en50221_tl_send_data(sl->tl, slot_id, connection_id, hdr, 5)) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Transport layer reports error %i on slot %i\n",
+		      en50221_tl_get_error(sl->tl), slot_id);
+	}
+	// callback to announce destruction to resource if it was ok
+	if (code == 0x00) {
+		pthread_mutex_lock(&sl->setcallback_lock);
+		en50221_sl_session_callback cb = sl->session;
+		void *cb_arg = sl->session_arg;
+		pthread_mutex_unlock(&sl->setcallback_lock);
+
+		if (cb)
+			cb(cb_arg, S_SCALLBACK_REASON_CLOSE, slot_id,
+			   session_number, resource_id);
+	}
+}
+
+static void en50221_sl_handle_create_session_response(struct en50221_session_layer *sl,
+						      uint8_t * data,
+						      uint32_t data_length,
+						      uint8_t slot_id,
+						      uint8_t connection_id)
+{
+	// check
+	if (data_length < 8) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %02x\n",
+		      slot_id);
+		return;
+	}
+	if (data[0] != 7) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %02x\n",
+		      slot_id);
+		return;
+	}
+	// extract session number
+	uint16_t session_number = (data[5] << 8) | data[6];
+
+	// check session number is ok
+	if (session_number >= sl->max_sessions) {
+		print(LOG_LEVEL, ERROR, 1, "Received bad session id %i\n",
+		      slot_id);
+		return;
+	}
+
+	pthread_mutex_lock(&sl->sessions[session_number].session_lock);
+	if (slot_id != sl->sessions[session_number].slot_id) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received unexpected session on invalid slot %i\n",
+		      slot_id);
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return;
+	}
+	if (connection_id != sl->sessions[session_number].connection_id) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received unexpected session on invalid slot %i\n",
+		      slot_id);
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return;
+	}
+	if (sl->sessions[session_number].state != S_STATE_IN_CREATION) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received unexpected session on invalid slot %i\n",
+		      slot_id);
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return;
+	}
+	// extract status
+	if (data[1] != S_STATUS_OPEN) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Session creation failed 0x%02x\n", data[1]);
+		sl->sessions[session_number].state = S_STATE_IDLE;
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+
+		// inform upper layers
+		pthread_mutex_lock(&sl->setcallback_lock);
+		en50221_sl_session_callback cb = sl->session;
+		void *cb_arg = sl->session_arg;
+		pthread_mutex_unlock(&sl->setcallback_lock);
+		if (cb)
+			cb(cb_arg, S_SCALLBACK_REASON_CONNECTFAIL, slot_id,
+			   session_number,
+			   sl->sessions[session_number].resource_id);
+		return;
+	}
+	// set it active
+	sl->sessions[session_number].state = S_STATE_ACTIVE;
+	pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+
+	// inform upper layers
+	pthread_mutex_lock(&sl->setcallback_lock);
+	en50221_sl_session_callback cb = sl->session;
+	void *cb_arg = sl->session_arg;
+	pthread_mutex_unlock(&sl->setcallback_lock);
+	if (cb)
+		cb(cb_arg, S_SCALLBACK_REASON_CONNECTED, slot_id,
+		   session_number,
+		   sl->sessions[session_number].resource_id);
+}
+
+static void en50221_sl_handle_close_session_response(struct en50221_session_layer *sl,
+						     uint8_t *data,
+						     uint32_t data_length,
+						     uint8_t slot_id,
+						     uint8_t connection_id)
+{
+	// check
+	if (data_length < 5) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %02x\n",
+		      slot_id);
+		return;
+	}
+	if (data[0] != 4) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %02x\n",
+		      slot_id);
+		return;
+	}
+	// extract session number
+	uint16_t session_number = (data[2] << 8) | data[3];
+
+	// check session number is ok
+	if (session_number >= sl->max_sessions) {
+		print(LOG_LEVEL, ERROR, 1, "Received bad session id %i\n", slot_id);
+		return;
+	}
+
+	pthread_mutex_lock(&sl->sessions[session_number].session_lock);
+	if (slot_id != sl->sessions[session_number].slot_id) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received unexpected session on invalid slot %i\n",
+		      slot_id);
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return;
+	}
+	if (connection_id != sl->sessions[session_number].connection_id) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received unexpected session on invalid slot %i\n",
+		      slot_id);
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return;
+	}
+	if (sl->sessions[session_number].state != S_STATE_IN_DELETION) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received unexpected session on invalid slot %i\n",
+		      slot_id);
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return;
+	}
+	// extract status
+	if (data[1] != 0x00) {
+		print(LOG_LEVEL, ERROR, 1, "Session close failed 0x%02x\n", data[1]);
+		// just fallthrough anyway
+	}
+	// completed
+	sl->sessions[session_number].state = S_STATE_IDLE;
+	pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+}
+
+static void en50221_sl_handle_session_package(struct en50221_session_layer *sl,
+					      uint8_t *data,
+					      uint32_t data_length,
+					      uint8_t slot_id,
+					      uint8_t connection_id)
+{
+	// check
+	if (data_length < 3) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %i\n",
+		      slot_id);
+		return;
+	}
+	if (data[0] != 2) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %i\n",
+		      slot_id);
+		return;
+	}
+	// get session number
+	uint16_t session_number = (data[1] << 8) | data[2];
+
+	// check it
+	if (session_number >= sl->max_sessions) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with bad session_number from module on slot %i\n",
+		      slot_id);
+		return;
+	}
+
+	pthread_mutex_lock(&sl->sessions[session_number].session_lock);
+	if (slot_id != sl->sessions[session_number].slot_id) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received unexpected session on invalid slot %i\n",
+		      slot_id);
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return;
+	}
+	if (connection_id != sl->sessions[session_number].connection_id) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received unexpected session on invalid slot %i\n",
+		      slot_id);
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return;
+	}
+	if (sl->sessions[session_number].state != S_STATE_ACTIVE) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with bad session_number from module on slot %i\n",
+		      slot_id);
+		pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+		return;
+	}
+
+	en50221_sl_resource_callback cb = sl->sessions[session_number].callback;
+	void *cb_arg = sl->sessions[session_number].callback_arg;
+	uint32_t resource_id = sl->sessions[session_number].resource_id;
+	pthread_mutex_unlock(&sl->sessions[session_number].session_lock);
+
+	// there can be > 1 APDU following the package - all for the same session/resource_id tho.
+	data += 3;
+	data_length -= 3;
+	while (data_length) {
+		// check length field
+		if (data_length < 3) {
+			print(LOG_LEVEL, ERROR, 1,
+			      "Received invalid sized session package from slot %i\n",
+			      slot_id);
+			return;
+		}
+		// parse the APDU's length field
+		int length_field_len;
+		uint16_t asn_data_length;
+		if ((length_field_len = asn_1_decode(&asn_data_length, data + 3, data_length - 3)) < 0) {
+			print(LOG_LEVEL, ERROR, 1,
+			      "Received invalid sized session package from slot %i\n",
+			      slot_id);
+			return;
+		}
+		uint32_t apdu_length = 3 + length_field_len + asn_data_length;
+
+		// check there is enough data
+		if (apdu_length > data_length) {
+			print(LOG_LEVEL, ERROR, 1,
+			      "Received invalid sized session package from slot %i\n",
+			      slot_id);
+			return;
+		}
+		// pass the APDU up to the higher layers
+		if (cb)
+			cb(cb_arg, slot_id, session_number, resource_id, data, apdu_length);
+
+		// next!
+		data += apdu_length;
+		data_length -= apdu_length;
+	}
+
+}
+
+static void en50221_sl_transport_callback(void *arg, int reason,
+					  uint8_t *data,
+					  uint32_t data_length,
+					  uint8_t slot_id,
+					  uint8_t connection_id)
+{
+	struct en50221_session_layer *sl =
+	    (struct en50221_session_layer *) arg;
+	uint32_t i;
+
+	// deal with the reason for this callback
+	switch (reason) {
+	case T_CALLBACK_REASON_DATA:
+		// fallthrough into rest of this function
+		break;
+
+	case T_CALLBACK_REASON_CONNECTIONOPEN:
+	{
+		pthread_mutex_lock(&sl->setcallback_lock);
+		en50221_sl_session_callback cb = sl->session;
+		void *cb_arg = sl->session_arg;
+		pthread_mutex_unlock(&sl->setcallback_lock);
+
+		if (cb)
+			cb(cb_arg, S_SCALLBACK_REASON_TC_CONNECT,
+				slot_id, connection_id, 0);
+		return;
+	}
+
+	case T_CALLBACK_REASON_CAMCONNECTIONOPEN:
+	{
+		pthread_mutex_lock(&sl->setcallback_lock);
+		en50221_sl_session_callback cb = sl->session;
+		void *cb_arg = sl->session_arg;
+		pthread_mutex_unlock(&sl->setcallback_lock);
+
+		if (cb)
+			cb(cb_arg,
+				S_SCALLBACK_REASON_TC_CAMCONNECT,
+				slot_id, connection_id, 0);
+		return;
+	}
+
+	case T_CALLBACK_REASON_CONNECTIONCLOSE:
+	{
+		pthread_mutex_lock(&sl->setcallback_lock);
+		en50221_sl_session_callback cb = sl->session;
+		void *cb_arg = sl->session_arg;
+		pthread_mutex_unlock(&sl->setcallback_lock);
+
+		for (i = 0; i < sl->max_sessions; i++) {
+			pthread_mutex_lock(&sl->sessions[i].session_lock);
+
+			if (sl->sessions[i].state == S_STATE_IDLE) {
+				pthread_mutex_unlock(&sl->sessions[i].session_lock);
+				continue;
+			}
+			if (sl->sessions[i].connection_id != connection_id) {
+				pthread_mutex_unlock(&sl->sessions[i].session_lock);
+				continue;
+			}
+
+			sl->sessions[i].state = S_STATE_IDLE;
+
+			uint8_t _slot_id = sl->sessions[i].slot_id;
+			uint32_t resource_id = sl->sessions[i].resource_id;
+			pthread_mutex_unlock(&sl->sessions[i].session_lock);
+
+			if (cb)
+				cb(cb_arg, S_SCALLBACK_REASON_CLOSE, _slot_id, i, resource_id);
+		}
+		return;
+	}
+
+	case T_CALLBACK_REASON_SLOTCLOSE:
+	{
+		pthread_mutex_lock(&sl->setcallback_lock);
+		en50221_sl_session_callback cb = sl->session;
+		void *cb_arg = sl->session_arg;
+		pthread_mutex_unlock(&sl->setcallback_lock);
+
+		for (i = 0; i < sl->max_sessions; i++) {
+			pthread_mutex_lock(&sl->sessions[i].session_lock);
+
+			if (sl->sessions[i].state == S_STATE_IDLE) {
+				pthread_mutex_unlock(&sl->sessions[i].session_lock);
+				continue;
+			}
+			if (sl->sessions[i].slot_id != slot_id) {
+				pthread_mutex_unlock(&sl->sessions[i].session_lock);
+				continue;
+			}
+			sl->sessions[i].state = S_STATE_IDLE;
+
+			uint32_t resource_id = sl->sessions[i].resource_id;
+			pthread_mutex_unlock(&sl->sessions[i].session_lock);
+
+			if (cb)
+				cb(cb_arg, S_SCALLBACK_REASON_CLOSE, slot_id, i, resource_id);
+
+		}
+		return;
+	}
+	}
+
+	// sanity check data length
+	if (data_length < 1) {
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received data with invalid length from module on slot %i\n",
+		      slot_id);
+		return;
+	}
+	// deal with the data
+	uint8_t spdu_tag = data[0];
+	switch (spdu_tag) {
+	case ST_OPEN_SESSION_REQ:
+		en50221_sl_handle_open_session_request(sl, data + 1,
+						       data_length - 1,
+						       slot_id,
+						       connection_id);
+		break;
+
+	case ST_CLOSE_SESSION_REQ:
+		en50221_sl_handle_close_session_request(sl, data + 1,
+							data_length - 1,
+							slot_id,
+							connection_id);
+		break;
+
+	case ST_SESSION_NUMBER:
+		en50221_sl_handle_session_package(sl, data + 1,
+						  data_length - 1, slot_id,
+						  connection_id);
+		break;
+
+	case ST_CREATE_SESSION_RES:
+		en50221_sl_handle_create_session_response(sl, data + 1,
+							  data_length - 1,
+							  slot_id,
+							  connection_id);
+		break;
+
+	case ST_CLOSE_SESSION_RES:
+		en50221_sl_handle_close_session_response(sl, data + 1,
+							 data_length - 1,
+							 slot_id,
+							 connection_id);
+		break;
+
+	default:
+		print(LOG_LEVEL, ERROR, 1,
+		      "Received unknown session tag %02x from module on slot %i",
+		      spdu_tag, slot_id);
+		break;
+	}
+}
+
+static int en50221_sl_alloc_new_session(struct en50221_session_layer *sl,
+					uint32_t resource_id,
+					uint8_t slot_id,
+					uint8_t connection_id,
+					en50221_sl_resource_callback
+					callback, void *arg)
+{
+	int session_number = -1;
+	uint32_t i;
+	for (i = 1; i < sl->max_sessions; i++) {
+		if (sl->sessions[i].state == S_STATE_IDLE) {
+			session_number = i;
+			break;
+		}
+	}
+	if (session_number == -1) {
+		sl->error = EN50221ERR_OUTOFSESSIONS;
+		return -1;
+	}
+	// setup the session
+	sl->sessions[session_number].state = S_STATE_IN_CREATION;
+	sl->sessions[session_number].resource_id = resource_id;
+	sl->sessions[session_number].slot_id = slot_id;
+	sl->sessions[session_number].connection_id = connection_id;
+	sl->sessions[session_number].callback = callback;
+	sl->sessions[session_number].callback_arg = arg;
+
+	// ok
+	return session_number;
+}