From 392f3f25ea9c08b473128f8d5960404aee033244 Mon Sep 17 00:00:00 2001
From: Marija Stevic <mstevic@eonerc.rwth-aachen.de>
Date: Thu, 24 Sep 2015 19:14:51 +0200
Subject: [PATCH 01/10] fixed the error in opal client src code

---
 clients/opal/udp/models/send_receive/src/s2ss.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/clients/opal/udp/models/send_receive/src/s2ss.c b/clients/opal/udp/models/send_receive/src/s2ss.c
index 5ea9a0cc1..97f825d60 100644
--- a/clients/opal/udp/models/send_receive/src/s2ss.c
+++ b/clients/opal/udp/models/send_receive/src/s2ss.c
@@ -132,7 +132,7 @@ static void *SendToIPPort(void *arg)
 			for (i = 0; i < msg.length; i++)
 				msg.data[i].f = (float) mdldata[i];
 
-			msg_size = MSG_LEN(msg.length);
+			msg_size = MSG_LEN(&msg);
 /**********************************************************************/
 
 			/* Perform the actual write to the ip port */
@@ -205,7 +205,7 @@ static void *RecvFromIPPort(void *arg)
 			if (msg.endian != MSG_ENDIAN_HOST)
 				msg_swap(&msg);
 			
-			msg_size =  MSG_LEN(msg.length);
+			msg_size =  MSG_LEN(&msg);
 /***********************************************************************/
 
 			if (n < 1) {

From 4d64550df64ba87bf65dae25b0b4b21c63189dc3 Mon Sep 17 00:00:00 2001
From: Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
Date: Fri, 25 Sep 2015 14:46:53 +0200
Subject: [PATCH 02/10] added README for LiveUSB

---
 contrib/liveusb/README.txt | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 contrib/liveusb/README.txt

diff --git a/contrib/liveusb/README.txt b/contrib/liveusb/README.txt
new file mode 100644
index 000000000..05f6d6e24
--- /dev/null
+++ b/contrib/liveusb/README.txt
@@ -0,0 +1,24 @@
+S2SS LiveUSB Image
+===================================================================
+
+This archive contains an image of Fedora installation
+which has been tuned for low latency and overall performance.
+It facilitates the setup of a S2SS instance and is designed to be used
+by partners of the Institute for Automation of Complex Power Systems (ACS).
+
+This image will automatically request an IP address via DHCP
+and create a SSH tunnel to the central orchestration server.
+This allows further configuration and control.
+
+The default credentials are:
+
+	User: root
+	Password: s2ss-admin
+
+Copy image with bundled tool [1] to a USB stick or a harddisk.
+The image is about 2GB in size.
+IMPORTANT: All contents of the stick will be wiped! Make backups!
+
+[1] http://www.alexpage.de/usb-image-tool/
+
+Contact: Steffen Vogel <StVogel@eonerc.rwth-aachen.de>
\ No newline at end of file

From 51f9a855c625a6dd2c3f7874616d9381c33a15dd Mon Sep 17 00:00:00 2001
From: Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
Date: Fri, 25 Sep 2015 15:07:03 +0200
Subject: [PATCH 03/10] fixed network byte order for sequence number and
 message length restructured code

---
 .../opal/udp/models/send_receive/src/s2ss.c   | 258 +++++++++---------
 1 file changed, 122 insertions(+), 136 deletions(-)

diff --git a/clients/opal/udp/models/send_receive/src/s2ss.c b/clients/opal/udp/models/send_receive/src/s2ss.c
index 97f825d60..9beef8095 100644
--- a/clients/opal/udp/models/send_receive/src/s2ss.c
+++ b/clients/opal/udp/models/send_receive/src/s2ss.c
@@ -87,7 +87,6 @@ static void *SendToIPPort(void *arg)
 
 	/* Data from the S2SS server */
 	struct msg msg = MSG_INIT(0);
-	int msg_size;
 
 #ifdef _DEBUG // TODO: workaround
 	msg_send = &msg;
@@ -96,69 +95,65 @@ static void *SendToIPPort(void *arg)
 	OpalPrint("%s: SendToIPPort thread started\n", PROGNAME);
 
 	OpalGetNbAsyncSendIcon(&nbSend);
-	if (nbSend >= 1) {
-		do {
-			/* This call unblocks when the 'Data Ready' line of a send icon is asserted. */
-			if ((n = OpalWaitForAsyncSendRequest(&SendID)) != EOK) {
-				ModelState = OpalGetAsyncModelState();
-				if ((ModelState != STATE_RESET) && (ModelState != STATE_STOP)) {
-					OpalSetAsyncSendIconError(n, SendID);
-					OpalPrint("%s: OpalWaitForAsyncSendRequest(), errno %d\n", PROGNAME, n);
-				}
-
-				continue;
+	if (nbSend < 1) {
+		OpalPrint("%s: SendToIPPort: No transimission block for this controller. Stopping thread.\n", PROGNAME);
+		return NULL;
+	}
+	
+	do {
+		/* This call unblocks when the 'Data Ready' line of a send icon is asserted. */
+		if ((n = OpalWaitForAsyncSendRequest(&SendID)) != EOK) {
+			ModelState = OpalGetAsyncModelState();
+			if ((ModelState != STATE_RESET) && (ModelState != STATE_STOP)) {
+				OpalSetAsyncSendIconError(n, SendID);
+				OpalPrint("%s: OpalWaitForAsyncSendRequest(), errno %d\n", PROGNAME, n);
 			}
 
-			/* No errors encountered yet */
+			continue;
+		}
+
+		/* No errors encountered yet */
+		OpalSetAsyncSendIconError(0, SendID);
+
+		/* Get the size of the data being sent by the unblocking SendID */
+		OpalGetAsyncSendIconDataLength(&mdldata_size, SendID);
+		if (mdldata_size / sizeof(double) > MSG_VALUES) {
+			OpalPrint("%s: Number of signals for SendID=%d exceeds allowed maximum (%d)\n",
+				PROGNAME, SendID, MSG_VALUES);
+			return NULL;
+		}
+
+		/* Read data from the model */
+		OpalGetAsyncSendIconData(mdldata, mdldata_size, SendID);
+		
+		msg.length = mdldata_size / sizeof(double);
+		for (i = 0; i < msg.length; i++)
+			msg.data[i].f = (float) mdldata[i];
+
+		/* Convert to network byte order */
+		msg.sequence = htonl(seq++);
+		msg.length = htons(msg.length);
+
+		/* Perform the actual write to the ip port */
+		if (SendPacket((char *) &msg, MSG_LEN(&msg)) < 0)
+			OpalSetAsyncSendIconError(errno, SendID);
+		else
 			OpalSetAsyncSendIconError(0, SendID);
 
-			/* Get the size of the data being sent by the unblocking SendID */
-			OpalGetAsyncSendIconDataLength(&mdldata_size, SendID);
-			if (mdldata_size / sizeof(double) > MSG_VALUES) {
-				OpalPrint("%s: Number of signals for SendID=%d exceeds allowed maximum (%d)\n",
-					PROGNAME, SendID, MSG_VALUES);
+		/* This next call allows the execution of the "asynchronous" process
+		 * to actually be synchronous with the model. To achieve this, you
+		 * should set the "Sending Mode" in the Async_Send block to
+		 * NEED_REPLY_BEFORE_NEXT_SEND or NEED_REPLY_NOW. This will force
+		 * the model to wait for this process to call this
+		* OpalAsyncSendRequestDone function before continuing. */
+		OpalAsyncSendRequestDone(SendID);
 
-				return NULL;
-			}
+		/* Before continuing, we make sure that the real-time model
+		 * has not been stopped. If it has, we quit. */
+		ModelState = OpalGetAsyncModelState();
+	} while ((ModelState != STATE_RESET) && (ModelState != STATE_STOP));
 
-			/* Read data from the model */
-			OpalGetAsyncSendIconData(mdldata, mdldata_size, SendID);
-
-/******* FORMAT TO SPECIFIC PROTOCOL HERE *****************************/
-			// msg.dev_id = SendID; /* Use the SendID as a device ID here */
-			msg.sequence = htons(seq++);
-			msg.length = mdldata_size / sizeof(double);
-
-			for (i = 0; i < msg.length; i++)
-				msg.data[i].f = (float) mdldata[i];
-
-			msg_size = MSG_LEN(&msg);
-/**********************************************************************/
-
-			/* Perform the actual write to the ip port */
-			if (SendPacket((char *) &msg, msg_size) < 0)
-				OpalSetAsyncSendIconError(errno, SendID);
-			else
-				OpalSetAsyncSendIconError(0, SendID);
-
-			/* This next call allows the execution of the "asynchronous" process
-			 * to actually be synchronous with the model. To achieve this, you
-			 * should set the "Sending Mode" in the Async_Send block to
-			 * NEED_REPLY_BEFORE_NEXT_SEND or NEED_REPLY_NOW. This will force
-			 * the model to wait for this process to call this
-			 * OpalAsyncSendRequestDone function before continuing. */
-			OpalAsyncSendRequestDone(SendID);
-
-			/* Before continuing, we make sure that the real-time model
-			 * has not been stopped. If it has, we quit. */
-			ModelState = OpalGetAsyncModelState();
-		} while ((ModelState != STATE_RESET) && (ModelState != STATE_STOP));
-
-		OpalPrint("%s: SendToIPPort: Finished\n", PROGNAME);
-	}
-	else {
-		OpalPrint("%s: SendToIPPort: No transimission block for this controller. Stopping thread.\n", PROGNAME);
-	}
+	OpalPrint("%s: SendToIPPort: Finished\n", PROGNAME);
 
 	return NULL;
 }
@@ -176,91 +171,82 @@ static void *RecvFromIPPort(void *arg)
 
 	/* Data from the S2SS server */
 	struct msg msg = MSG_INIT(0);
-	unsigned msg_size;
 
 	OpalPrint("%s: RecvFromIPPort thread started\n", PROGNAME);
 
 	OpalGetNbAsyncRecvIcon(&nbRecv);
-	if (nbRecv >= 1) {
-		do {
-
-/******* FORMAT TO SPECIFIC PROTOCOL HERE ******************************/
-			n  = RecvPacket((char *) &msg, sizeof(msg), 1.0);
-
-			/** @todo: Check and ntohs() sequence number! */
-
-			if (msg.version != MSG_VERSION) {
-				OpalPrint("%s: Received message with unknown version. Skipping..\n", PROGNAME);
-				continue;
-			}
-			else if (msg.type != MSG_TYPE_DATA) {
-				OpalPrint("%s: Received no data. Skipping..\n", PROGNAME);
-				continue;
-			}
-			
-			/** @todo: We may check the sequence number here. */
-
-			msg.sequence = ntohs(msg.sequence);
-			
-			if (msg.endian != MSG_ENDIAN_HOST)
-				msg_swap(&msg);
-			
-			msg_size =  MSG_LEN(&msg);
-/***********************************************************************/
-
-			if (n < 1) {
-				ModelState = OpalGetAsyncModelState();
-				if ((ModelState != STATE_RESET) && (ModelState != STATE_STOP)) {
-					// n ==  0 means timeout, so we continue silently
-					//if (n == 0)
-					//	OpalPrint("%s: Timeout while waiting for data\n", PROGNAME, errno);
-					// n == -1 means a more serious error, so we print it
-					if (n == -1)
-						OpalPrint("%s: Error %d while waiting for data\n", PROGNAME, errno);
-					continue;
-				}
-				break;
-			}
-			else if (n != msg_size) {
-				OpalPrint("%s: Received incoherent packet (size: %d, complete: %d)\n", PROGNAME, n, msg_size);
-				continue;
-			}
-
-/******* FORMAT TO SPECIFIC PROTOCOL HERE *******************************/
-			OpalSetAsyncRecvIconStatus(msg.sequence, RecvID);	/* Set the Status to the message ID */
-			OpalSetAsyncRecvIconError(0, RecvID);			/* Set the Error to 0 */
-
-			/* Get the number of signals to send back to the model */
-			OpalGetAsyncRecvIconDataLength(&mdldata_size, RecvID);
-
-			if (mdldata_size / sizeof(double) > MSG_VALUES) {
-				OpalPrint("%s: Number of signals for RecvID=%d (%d) exceeds allowed maximum (%d)\n",
-					PROGNAME, RecvID, mdldata_size / sizeof(double), MSG_VALUES);
-				return NULL;
-			}
-
-			if (mdldata_size / sizeof(double) > msg.length) {
-				OpalPrint("%s: Number of signals for RecvID=%d (%d) exceeds what was received (%d)\n",
-					PROGNAME, RecvID, mdldata_size / sizeof(double), msg.length);
-			}
-
-			for (i = 0; i < msg.length; i++)
-				mdldata[i] = (double) msg.data[i].f;
-/************************************************************************/
-
-			OpalSetAsyncRecvIconData(mdldata, mdldata_size, RecvID);
-
-			/* Before continuing, we make sure that the real-time model
-			 * has not been stopped. If it has, we quit. */
-			ModelState = OpalGetAsyncModelState();
-		} while ((ModelState != STATE_RESET) && (ModelState != STATE_STOP));
-
-		OpalPrint("%s: RecvFromIPPort: Finished\n", PROGNAME);
-	}
-	else {
+	if (nbRecv < 1) {
 		OpalPrint("%s: RecvFromIPPort: No reception block for this controller. Stopping thread.\n", PROGNAME);
+		return NULL;
 	}
 
+	do {
+		/* Receive message */
+		n  = RecvPacket((char *) &msg, sizeof(msg), 1.0);
+		if (n < 1) {
+			ModelState = OpalGetAsyncModelState();
+			if ((ModelState != STATE_RESET) && (ModelState != STATE_STOP)) {
+				if (n ==  0) /* timeout, so we continue silently */
+					OpalPrint("%s: Timeout while waiting for data\n", PROGNAME, errno);
+				if (n == -1) /* a more serious error, so we print it */
+					OpalPrint("%s: Error %d while waiting for data\n", PROGNAME, errno);
+					
+				continue;
+			}
+			break;
+		}
+
+		/* Check message contents */
+		if (msg.version != MSG_VERSION) {
+			OpalPrint("%s: Received message with unknown version. Skipping..\n", PROGNAME);
+			continue;
+		}
+		
+		if (msg.type != MSG_TYPE_DATA) {
+			OpalPrint("%s: Received no data. Skipping..\n", PROGNAME);
+			continue;
+		}
+			
+		/* Convert to host byte order */
+		msg.sequence = ntohl(msg.sequence);
+		msg.length = ntohs(msg.length);
+		
+		if (n != MSG_LEN(&msg)) {
+			OpalPrint("%s: Received incoherent packet (size: %d, complete: %d)\n", PROGNAME, n, MSG_LEN(&msg));
+			continue;
+		}
+			
+		if (msg.endian != MSG_ENDIAN_HOST)
+			msg_swap(&msg);
+
+		/* Update OPAL model */
+		OpalSetAsyncRecvIconStatus(msg.sequence, RecvID);	/* Set the Status to the message ID */
+		OpalSetAsyncRecvIconError(0, RecvID);			/* Set the Error to 0 */
+
+		/* Get the number of signals to send back to the model */
+		OpalGetAsyncRecvIconDataLength(&mdldata_size, RecvID);
+		if (mdldata_size / sizeof(double) > MSG_VALUES) {
+			OpalPrint("%s: Number of signals for RecvID=%d (%d) exceeds allowed maximum (%d)\n",
+				PROGNAME, RecvID, mdldata_size / sizeof(double), MSG_VALUES);
+			return NULL;
+		}
+
+		if (mdldata_size / sizeof(double) > msg.length)
+			OpalPrint("%s: Number of signals for RecvID=%d (%d) exceeds what was received (%d)\n",
+				PROGNAME, RecvID, mdldata_size / sizeof(double), msg.length);
+
+		for (i = 0; i < msg.length; i++)
+			mdldata[i] = (double) msg.data[i].f;
+
+		OpalSetAsyncRecvIconData(mdldata, mdldata_size, RecvID);
+
+		/* Before continuing, we make sure that the real-time model
+		 * has not been stopped. If it has, we quit. */
+		ModelState = OpalGetAsyncModelState();
+	} while ((ModelState != STATE_RESET) && (ModelState != STATE_STOP));
+
+	OpalPrint("%s: RecvFromIPPort: Finished\n", PROGNAME);
+
 	return NULL;
 }
 

From ec2595e70392c49ab799eb05b43f2a2ecdd4563f Mon Sep 17 00:00:00 2001
From: Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
Date: Sun, 27 Sep 2015 14:47:17 +0200
Subject: [PATCH 04/10] renamed README

---
 clients/{README.txt => README.md} | 2 ++
 1 file changed, 2 insertions(+)
 rename clients/{README.txt => README.md} (92%)

diff --git a/clients/README.txt b/clients/README.md
similarity index 92%
rename from clients/README.txt
rename to clients/README.md
index 3ce8ce243..85ccf0f48 100644
--- a/clients/README.txt
+++ b/clients/README.md
@@ -1,3 +1,5 @@
+# S2SS clients
+
 This directory contains code and projects to connect
 various simulators and tools to the S2SS server.
 

From c75e03db7752a872f327ab9de2558abb02a50b3f Mon Sep 17 00:00:00 2001
From: Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
Date: Sun, 27 Sep 2015 16:04:15 +0200
Subject: [PATCH 05/10] moved some stuff to InetDistSim repository because it
 does not belong to S2SS

---
 contrib/liveusb/README.txt                    | 24 --------
 contrib/liveusb/chroot.sh                     | 10 ----
 contrib/liveusb/etc/default/grub              |  7 ---
 contrib/liveusb/etc/hostname                  |  1 -
 contrib/liveusb/etc/hosts                     | 10 ----
 contrib/liveusb/etc/image-release             |  1 -
 contrib/liveusb/etc/image/setup.sh            |  1 -
 contrib/liveusb/etc/modprobe.d/blacklist.conf |  3 -
 contrib/liveusb/etc/modprobe.d/e1000e.conf    |  3 -
 contrib/liveusb/etc/sysconfig/ip6tables       | 31 ----------
 contrib/liveusb/etc/sysconfig/iptables        | 34 -----------
 contrib/liveusb/etc/sysconfig/network         |  1 -
 .../etc/systemd/system/dhclient.service       | 15 -----
 .../etc/systemd/system/mongoose.service       | 15 -----
 .../liveusb/etc/systemd/system/setup.service  | 16 ------
 contrib/liveusb/etc/tuned/active_profile      |  1 -
 contrib/liveusb/prepare.sh                    |  9 ---
 contrib/liveusb/setup.sh                      | 56 -------------------
 contrib/liveusb/update_boot.sh                | 24 --------
 contrib/liveusb/yum-packages.txt              | 56 -------------------
 contrib/tinc.sh                               | 45 ---------------
 21 files changed, 363 deletions(-)
 delete mode 100644 contrib/liveusb/README.txt
 delete mode 100755 contrib/liveusb/chroot.sh
 delete mode 100644 contrib/liveusb/etc/default/grub
 delete mode 100644 contrib/liveusb/etc/hostname
 delete mode 100644 contrib/liveusb/etc/hosts
 delete mode 100644 contrib/liveusb/etc/image-release
 delete mode 120000 contrib/liveusb/etc/image/setup.sh
 delete mode 100644 contrib/liveusb/etc/modprobe.d/blacklist.conf
 delete mode 100644 contrib/liveusb/etc/modprobe.d/e1000e.conf
 delete mode 100644 contrib/liveusb/etc/sysconfig/ip6tables
 delete mode 100644 contrib/liveusb/etc/sysconfig/iptables
 delete mode 100644 contrib/liveusb/etc/sysconfig/network
 delete mode 100644 contrib/liveusb/etc/systemd/system/dhclient.service
 delete mode 100644 contrib/liveusb/etc/systemd/system/mongoose.service
 delete mode 100644 contrib/liveusb/etc/systemd/system/setup.service
 delete mode 100644 contrib/liveusb/etc/tuned/active_profile
 delete mode 100644 contrib/liveusb/prepare.sh
 delete mode 100755 contrib/liveusb/setup.sh
 delete mode 100755 contrib/liveusb/update_boot.sh
 delete mode 100644 contrib/liveusb/yum-packages.txt
 delete mode 100755 contrib/tinc.sh

diff --git a/contrib/liveusb/README.txt b/contrib/liveusb/README.txt
deleted file mode 100644
index 05f6d6e24..000000000
--- a/contrib/liveusb/README.txt
+++ /dev/null
@@ -1,24 +0,0 @@
-S2SS LiveUSB Image
-===================================================================
-
-This archive contains an image of Fedora installation
-which has been tuned for low latency and overall performance.
-It facilitates the setup of a S2SS instance and is designed to be used
-by partners of the Institute for Automation of Complex Power Systems (ACS).
-
-This image will automatically request an IP address via DHCP
-and create a SSH tunnel to the central orchestration server.
-This allows further configuration and control.
-
-The default credentials are:
-
-	User: root
-	Password: s2ss-admin
-
-Copy image with bundled tool [1] to a USB stick or a harddisk.
-The image is about 2GB in size.
-IMPORTANT: All contents of the stick will be wiped! Make backups!
-
-[1] http://www.alexpage.de/usb-image-tool/
-
-Contact: Steffen Vogel <StVogel@eonerc.rwth-aachen.de>
\ No newline at end of file
diff --git a/contrib/liveusb/chroot.sh b/contrib/liveusb/chroot.sh
deleted file mode 100755
index 6e02c1bed..000000000
--- a/contrib/liveusb/chroot.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/bin/bash
-
-mount /dev/sdb1 /media/usb
-
-for part in dev sys proc; do
-	umount /media/usb/$part
-	mount -o bind /$part /media/usb/$part
-done
-
-chroot /media/usb
diff --git a/contrib/liveusb/etc/default/grub b/contrib/liveusb/etc/default/grub
deleted file mode 100644
index d3bd7ac6b..000000000
--- a/contrib/liveusb/etc/default/grub
+++ /dev/null
@@ -1,7 +0,0 @@
-GRUB_TIMEOUT=5
-GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
-GRUB_DEFAULT=1
-GRUB_DISABLE_SUBMENU=false
-GRUB_TERMINAL_OUTPUT="console"
-GRUB_CMDLINE_LINUX="isolcpus=6,7 selinux=0 audit=0"
-GRUB_DISABLE_RECOVERY=true
diff --git a/contrib/liveusb/etc/hostname b/contrib/liveusb/etc/hostname
deleted file mode 100644
index da598be9b..000000000
--- a/contrib/liveusb/etc/hostname
+++ /dev/null
@@ -1 +0,0 @@
-unknown-s2ss
diff --git a/contrib/liveusb/etc/hosts b/contrib/liveusb/etc/hosts
deleted file mode 100644
index 05fc89de2..000000000
--- a/contrib/liveusb/etc/hosts
+++ /dev/null
@@ -1,10 +0,0 @@
-127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
-::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
-
-# Orchestrator
-
-# ACS hosts
-134.130.169.31	acs-s2ss
-134.130.169.32	acs-gtfpga
-137.226.160.69	acs-opal
-137.226.160.115	acs-workstation
diff --git a/contrib/liveusb/etc/image-release b/contrib/liveusb/etc/image-release
deleted file mode 100644
index bd8b58947..000000000
--- a/contrib/liveusb/etc/image-release
+++ /dev/null
@@ -1 +0,0 @@
-0.5-turin
diff --git a/contrib/liveusb/etc/image/setup.sh b/contrib/liveusb/etc/image/setup.sh
deleted file mode 120000
index a645eb309..000000000
--- a/contrib/liveusb/etc/image/setup.sh
+++ /dev/null
@@ -1 +0,0 @@
-setup.sh
\ No newline at end of file
diff --git a/contrib/liveusb/etc/modprobe.d/blacklist.conf b/contrib/liveusb/etc/modprobe.d/blacklist.conf
deleted file mode 100644
index 6874104fc..000000000
--- a/contrib/liveusb/etc/modprobe.d/blacklist.conf
+++ /dev/null
@@ -1,3 +0,0 @@
-blacklist snd_hda_intel
-blacklist nouveau
-blacklist mei_me
diff --git a/contrib/liveusb/etc/modprobe.d/e1000e.conf b/contrib/liveusb/etc/modprobe.d/e1000e.conf
deleted file mode 100644
index 74dea577d..000000000
--- a/contrib/liveusb/etc/modprobe.d/e1000e.conf
+++ /dev/null
@@ -1,3 +0,0 @@
-# More conservative interrupt throttling for better latency
-# https://www.kernel.org/doc/Documentation/networking/e1000e.txt
-option e1000e InterruptThrottleRate=1
diff --git a/contrib/liveusb/etc/sysconfig/ip6tables b/contrib/liveusb/etc/sysconfig/ip6tables
deleted file mode 100644
index 13f6e5ed7..000000000
--- a/contrib/liveusb/etc/sysconfig/ip6tables
+++ /dev/null
@@ -1,31 +0,0 @@
-*filter
-:INPUT ACCEPT
-:FORWARD ACCEPT
-:OUTPUT ACCEPT
-
-# Allow loopback traffic
--A INPUT -i lo -j ACCEPT
-
-# Allow established connections, and those not coming from the outside
--A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-
-# Allow HTTP
--A INPUT -p tcp --dport http -m conntrack --ctstate NEW -j ACCEPT
-
-# Allow SSH
--A INPUT -p tcp --dport ssh -m conntrack --ctstate NEW -j ACCEPT
-
-# Allow Tinc
--A INPUT -p udp --dport tinc -j ACCEPT
--A INPUT -p tcp --dport tinc -j ACCEPT
-
-# Accept Pings
--A INPUT -p icmpv6 -j ACCEPT
-
-# Reject everything else
--A INPUT -j REJECT
-
-# We wont act as a router
--A FORWARD -j REJECT
-
-COMMIT
diff --git a/contrib/liveusb/etc/sysconfig/iptables b/contrib/liveusb/etc/sysconfig/iptables
deleted file mode 100644
index cfdd9d2f3..000000000
--- a/contrib/liveusb/etc/sysconfig/iptables
+++ /dev/null
@@ -1,34 +0,0 @@
-*filter
-:INPUT ACCEPT
-:FORWARD ACCEPT
-:OUTPUT ACCEPT
-
-# Allow loopback traffic
--A INPUT -i lo -j ACCEPT
-
-# Allow established connections, and those not coming from the outside
--A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-
-# Allow HTTP
--A INPUT -p tcp --dport http -m conntrack --ctstate NEW -j ACCEPT
-
-# Allow VPN
--A INPUT -s 10.0.0.0/8 -j ACCEPT
-
-# Allow SSH
--A INPUT -p tcp --dport ssh -m conntrack --ctstate NEW -j ACCEPT
-
-# Allow Tinc
--A INPUT -p udp --dport tinc -j ACCEPT
--A INPUT -p tcp --dport tinc -j ACCEPT
-
-# Accept Pings
--A INPUT -p icmp -j ACCEPT
-
-# Reject everything else
--A INPUT -j REJECT
-
-# We wont act as a router
--A FORWARD -j REJECT
-
-COMMIT
diff --git a/contrib/liveusb/etc/sysconfig/network b/contrib/liveusb/etc/sysconfig/network
deleted file mode 100644
index 61c4a5ad8..000000000
--- a/contrib/liveusb/etc/sysconfig/network
+++ /dev/null
@@ -1 +0,0 @@
-NETWORKING=yes
diff --git a/contrib/liveusb/etc/systemd/system/dhclient.service b/contrib/liveusb/etc/systemd/system/dhclient.service
deleted file mode 100644
index 71f78f25f..000000000
--- a/contrib/liveusb/etc/systemd/system/dhclient.service
+++ /dev/null
@@ -1,15 +0,0 @@
-[Unit]
-Description=dhclient on all interfaces
-Wants=network.target
- 
-[Service]
-Type=forking
-ExecStart=/sbin/dhclient -4 -w
-
-Restart=on-failure
-RestartSec=10
-
-TimeoutSec=60
- 
-[Install]
-WantedBy=network.target
diff --git a/contrib/liveusb/etc/systemd/system/mongoose.service b/contrib/liveusb/etc/systemd/system/mongoose.service
deleted file mode 100644
index 2ff7070d7..000000000
--- a/contrib/liveusb/etc/systemd/system/mongoose.service
+++ /dev/null
@@ -1,15 +0,0 @@
-[Unit]
-Description=The mongoose Web server
-After=network.target
-
-[Service]
-Type=simple
-User=nobody
-Group=nobody
-Restart=always
-ExecStart=/usr/bin/mongoose -p 80 -r /var/www/
-StandardOutput=syslog
-SyslogIdentifier=mongoose
-
-[Install]
-WantedBy=multi-user.target
diff --git a/contrib/liveusb/etc/systemd/system/setup.service b/contrib/liveusb/etc/systemd/system/setup.service
deleted file mode 100644
index b5ea9a011..000000000
--- a/contrib/liveusb/etc/systemd/system/setup.service
+++ /dev/null
@@ -1,16 +0,0 @@
-[Unit]
-Description=S2SS LiveUSB Image setup
-Requires=network-online.target
-
-[Service]
-Type=simple
-ExecStart=/etc/image/setup.sh
-RemainAfterExit=yes
-
-Restart=on-failure
-RestartSec=10
-
-TimeoutSec=60
-
-[Install]
-WantedBy=multi-user.target
diff --git a/contrib/liveusb/etc/tuned/active_profile b/contrib/liveusb/etc/tuned/active_profile
deleted file mode 100644
index 239b12e08..000000000
--- a/contrib/liveusb/etc/tuned/active_profile
+++ /dev/null
@@ -1 +0,0 @@
-latency-performance
diff --git a/contrib/liveusb/prepare.sh b/contrib/liveusb/prepare.sh
deleted file mode 100644
index eb7a9a755..000000000
--- a/contrib/liveusb/prepare.sh
+++ /dev/null
@@ -1,9 +0,0 @@
-#!/bin/bash
-
-rpm -Uvh http://ccrma.stanford.edu/planetccrma/mirror/fedora/linux/planetccrma/20/i386/planetccrma-repo-1.1-3.fc20.ccrma.noarch.rpm 
-
-yum update
-
-yum install planetccrma-core
-
-source update_boot.sh
diff --git a/contrib/liveusb/setup.sh b/contrib/liveusb/setup.sh
deleted file mode 100755
index e2918ff18..000000000
--- a/contrib/liveusb/setup.sh
+++ /dev/null
@@ -1,56 +0,0 @@
-#!/bin/bash
-
-set -e
-
-RECIPIENTS="stvogel@eonerc.rwth-aachen.de,mstevic@eonerc.rwth-aachen.de"
-
-SERVER=s2ss.0l.de
-USER=acs
-
-PORT=$(shuf -i 60000-65535 -n 1)
-
-# wait for working network connection
-while ! curl http://canihazip.com/s &> /dev/null; do
-	sleep 1
-done
-
-IP=$(curl -s http://canihazip.com/s)
-HOSTNAME=$(dig +short -x $IP)
-if [ -z "$HOSTNAME" ]; then
-	HOSTNAME=$(hostname)
-fi
-
-# check if system has net connectivity. otherwise die...
-ssh -q -o ConnectTimeout=2 $USER@$SERVER
-
-# setup SSH tunnel for mail notification
-ssh -f -N -L 25:localhost:25 $USER@$SERVER
-# setup SSH reverse tunnel for remote administration
-ssh -f -N -R $PORT:localhost:22 $USER@$SERVER
-
-# send mail with notification about new node
-sendmail "$RECIPIENTS" <<EOF
-Subject: New S2SS node alive: $IP ($HOSTNAME)
-From: Simulator2Simulator Server <acs@0l.de>
-To: $RECIPIENTS
-
-There's a new host with the S2SS LiveUSB Image running:
-
-Version: $(cat /etc/image-release)
-Reverse SSH tunnel port: $PORT
-Internet IP: $IP
-Hostname: $HOSTNAME
-
-Latency:
-$(ping -qc 5 $SERVER)
-
-Traceroute:
-$(traceroute $SERVER)
-
-Interfaces:
-$(ip addr)
-
-Hardware:
-$(lshw)
-
-EOF
diff --git a/contrib/liveusb/update_boot.sh b/contrib/liveusb/update_boot.sh
deleted file mode 100755
index f0c87ca0e..000000000
--- a/contrib/liveusb/update_boot.sh
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/bin/sh
-
-# author: Christian Berendt <mail@cberendt.net>
-
-set -x
-
-for kernel in $(find /boot/vmlinuz*); do
-    version=$(basename $kernel)
-    version=${version#*-}
-    if [ ! -e /boot/initramfs-$version.img ]; then
-        sudo /usr/bin/dracut /boot/initramfs-$version.img $version
-    fi
-done
-
-for image in $(find /boot/initramfs*); do
-    version=${image%.img}
-    version=${version#*initramfs-}
-    if [ ! -e /boot/vmlinuz-$version ]; then
-        sudo rm $image
-    fi
-done
-
-/usr/sbin/grub2-mkconfig -o /boot/grub2/grub.cfg
-
diff --git a/contrib/liveusb/yum-packages.txt b/contrib/liveusb/yum-packages.txt
deleted file mode 100644
index 0a5117f19..000000000
--- a/contrib/liveusb/yum-packages.txt
+++ /dev/null
@@ -1,56 +0,0 @@
-authconfig-6.2.6-4.fc20.x86_64
-automake-1.13.4-6.fc20.noarch
-bash-completion-2.1-3.fc20.noarch
-bind-utils-9.9.4-18.P2.fc20.x86_64
-biosdevname-0.5.0-2.fc20.x86_64
-bzip2-1.0.6-9.fc20.x86_64
-dhclient-4.2.7-2.fc20.x86_64
-dosfstools-3.0.27-1.fc20.x86_64
-dracut-config-rescue-037-11.git20140402.fc20.x86_64
-e2fsprogs-1.42.12-3.fc20.x86_64
-efibootmgr-0.11.0-1.fc20.x86_64
-ftp-0.17-65.fc20.x86_64
-gcc-4.8.3-7.fc20.x86_64
-gdb-7.7.1-21.fc20.x86_64
-gdisk-0.8.10-2.fc20.x86_64
-git-svn-1.9.3-2.fc20.x86_64
-grub2-2.00-27.fc20.x86_64
-htop-1.0.3-3.fc20.x86_64
-iptables-services-1.4.19.1-1.fc20.x86_64
-kbd-1.15.5-12.fc20.x86_64
-kernel-modules-extra-3.18.9-100.fc20.x86_64
-kernel-rt-modules-extra-3.14.29-200.rt26.1.fc20.ccrma.x86_64
-libconfig-1.4.9-5.fc20.x86_64
-lshw-B.02.17-2.fc20.x86_64
-lzo-devel-2.08-1.fc20.x86_64
-mailx-12.5-11.fc20.x86_64
-man-db-2.6.5-6.fc20.x86_64
-minicom-2.6.2-4.fc20.x86_64
-nano-2.3.2-5.fc20.x86_64
-nmap-6.45-1.fc20.x86_64
-ntp-4.2.6p5-20.fc20.x86_64
-numactl-2.0.9-2.fc20.x86_64
-openssh-server-6.4p1-8.fc20.x86_64
-openssl-devel-1.0.1e-41.fc20.x86_64
-parted-3.1-13.fc20.x86_64
-passwd-0.79-2.fc20.x86_64
-patch-2.7.1-7.fc20.x86_64
-pciutils-devel-3.3.0-1.fc20.x86_64
-planetccrma-repo-1.1-3.fc20.ccrma.noarch
-policycoreutils-2.2.5-4.fc20.x86_64
-psmisc-22.20-3.fc20.x86_64
-readline-devel-6.2-10.fc20.x86_64
-rootfiles-8.1-16.fc20.noarch
-schedtool-1.3.0-9.fc20.x86_64
-screen-4.1.0-0.19.20120314git3c2946.fc20.x86_64
-setserial-2.17-34.fc20.x86_64
-socat-1.7.2.4-1.fc20.x86_64
-ssmtp-2.64-14.fc20.x86_64
-sudo-1.8.12-1.fc20.x86_64
-tar-1.26-31.fc20.x86_64
-tcpdump-4.5.1-3.fc20.x86_64
-texinfo-5.1-4.fc20.x86_64
-traceroute-2.0.20-1.fc20.x86_64
-tuned-2.4.1-3.fc20.noarch
-wget-1.16.1-2.fc20.x86_64
-yum-utils-1.1.31-27.fc20.noarch
diff --git a/contrib/tinc.sh b/contrib/tinc.sh
deleted file mode 100755
index a93de032d..000000000
--- a/contrib/tinc.sh
+++ /dev/null
@@ -1,45 +0,0 @@
-#!/bin/sh
-
-# die on error
-set -e
-
-if [ "$(hostname)" != "acs-s2ss" ]; then
-	echo "This script has to be run only acs-s2ss!" 1>&2
-	exit 1
-fi
-
-if [ "$(id -u)" != "0" ]; then
-	echo -e "This script must be run as root" 1>&2
-	exit 1
-fi
-
-IP=78.91.103.24
-PORT=12010
-IPT=iptables
-RULE1="-p udp --dport $PORT -s $IP -j REJECT"
-RULE2="-p tcp --dport $PORT -s $IP -j REJECT"
-
-case $1 in
-    block)
-	$IPT -I INPUT 1 $RULE1 
-	$IPT -I INPUT 1 $RULE2
-	service tincd restart
-	;;
-
-    unblock)
-	$IPT -D INPUT $RULE1
-	$IPT -D INPUT $RULE2
-	service tincd restart
-	;;
-
-    status)
-	$IPT -C INPUT $RULE1 && echo "Tinc UDP is blocked"
-	$IPT -C INPUT $RULE2 && echo "Tinc TCP is blocked"
-
-	echo -n "Sintef "
-	tinc -n s2ss info sintef | grep "Reachability"
-
-	echo -n "Frankfurt "
-	tinc -n s2ss info fra | grep "Reachability"
-	;;
-esac

From 2c669866dd5fbca8dd769e2a6731e2e87022ebec Mon Sep 17 00:00:00 2001
From: Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
Date: Sun, 27 Sep 2015 17:53:39 +0200
Subject: [PATCH 06/10] fixed typo in Makefile

---
 server/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/server/Makefile b/server/Makefile
index a0d010e39..88b65f1d0 100644
--- a/server/Makefile
+++ b/server/Makefile
@@ -31,7 +31,7 @@ endif
 # Enable file node type support
 ifndef DISABLE_FILE
 	override CFLAGS += -DENABLE_FILE
-	OBJS   += ngsi.o
+	OBJS   += file.o
 endif
 
 # Enable Socket node type when libnl3 is available

From cf152ad4e06abbdfaba490b7f68e34ad3a9f5b9a Mon Sep 17 00:00:00 2001
From: Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
Date: Sun, 27 Sep 2015 18:03:41 +0200
Subject: [PATCH 07/10] updated build dependencies in documentation

---
 documentation/Install.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/documentation/Install.md b/documentation/Install.md
index d70aaf05e..a509fef1e 100644
--- a/documentation/Install.md
+++ b/documentation/Install.md
@@ -12,11 +12,11 @@ Install libraries including developement headers for:
  
 Use the following command to install the dependencies under Debian-based distributions:
 
-    $ sudo apt-get install libconfig-dev libnl-3-dev libnl-route-3-dev
+    $ sudo apt-get install build-essential pkg-config libconfig-dev libnl-3-dev libnl-route-3-dev libpci-deb libjansson-dev libcurl4-openssl-dev uuid-dev
 
 or the following line for Fedora / CentOS / Redhat systems:
 
-    $ sudo yum install iproute2 libconfig-devel libnl3-devel
+    $ sudo yum install pkgconfig gcc make libconfig-devel libnl3-devel pciutils-devel libcurl-devel jansson-devel libuuid-devel
 
 **Important:** Please note that the server requires the
 [iproute2](http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2)

From eee4d6151382a3c6ef709d385bf59b571f5cc74a Mon Sep 17 00:00:00 2001
From: Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
Date: Sun, 27 Sep 2015 18:05:35 +0200
Subject: [PATCH 08/10] fixed another unimportant typo

---
 server/src/server.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/server/src/server.c b/server/src/server.c
index 0ef40890d..589a8582f 100644
--- a/server/src/server.c
+++ b/server/src/server.c
@@ -111,7 +111,7 @@ static void usage(const char *name)
 #ifdef ENABLE_SOCKET
 	printf(" - socket: Network socket (libnl3)\n");
 #endif
-#ifdef ENABLE_PCI
+#ifdef ENABLE_GTFPGA
 	printf(" - gtfpga: GTFPGA PCIe card (libpci)\n");
 #endif
 #ifdef ENABLE_OPAL_ASYNC

From 74d163db555e3df70820c68c4558e4132f5c287a Mon Sep 17 00:00:00 2001
From: Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
Date: Sun, 27 Sep 2015 20:27:47 +0200
Subject: [PATCH 09/10] fixed reference counting for jansson objects

---
 server/src/ngsi.c | 66 ++++++++++++++++++++++++-----------------------
 1 file changed, 34 insertions(+), 32 deletions(-)

diff --git a/server/src/ngsi.c b/server/src/ngsi.c
index 06eb187c1..161e3a5eb 100644
--- a/server/src/ngsi.c
+++ b/server/src/ngsi.c
@@ -113,6 +113,8 @@ static int ngsi_request(CURL *handle, json_t *content, json_t **response)
 	
 	if (response)
 		*response = resp;
+	else
+		json_decref(resp);
 	
 	free(post);
 	free(chunk.data);
@@ -124,27 +126,27 @@ void ngsi_prepare_context(struct node *n, config_setting_t *mapping)
 {	
 	struct ngsi *i = n->ngsi;
 
-	i->context = json_object();
-	json_t *elements = json_array();
-	
-	json_object_set(i->context, "contextElements", elements);
-	
+	i->context     = json_object();
 	i->context_len = config_setting_length(mapping);
 	i->context_map = alloc(i->context_len * sizeof(json_t *));
+
+	json_t *elements = json_array();
 	
 	for (int j = 0; j < i->context_len; j++) {
+		/* Get token */
 		config_setting_t *ctoken = config_setting_get_elem(mapping, j);
-
 		const char *stoken = config_setting_get_string(ctoken);
 		if (!stoken)
 			cerror(mapping, "Invalid token");
 
+		/* Parse token */
 		char eid[64], etype[64], aname[64], atype[64];
 		if (sscanf(stoken, "%63[^().](%63[^().]).%63[^().](%63[^().])", eid, etype, aname, atype) != 4)
 			cerror(ctoken, "Invalid token: '%s'", stoken);
 
 		/* Create entity */
-		json_t *attributes;
+		json_t *attributes; /* borrowed reference */
+
 		json_t *entity = json_lookup(elements, "id", eid);
 		if (!entity) {
 			entity = json_pack("{ s: s, s: s, s: b }",
@@ -152,10 +154,10 @@ void ngsi_prepare_context(struct node *n, config_setting_t *mapping)
 				"type",		etype,
 				"isPattern", 	0
 			);
+			json_array_append_new(elements, entity);
 		
 			attributes = json_array();
-			json_object_set(entity, "attributes", attributes);
-			json_array_append(elements, entity);
+			json_object_set_new(entity, "attributes", attributes);
 		}
 		else {
 			if (i->structure == NGSI_CHILDREN)
@@ -164,55 +166,55 @@ void ngsi_prepare_context(struct node *n, config_setting_t *mapping)
 			attributes = json_object_get(entity, "attributes");
 		}
 
-		/* Create attribute */
+		/* Create attribute for entity */
 		if (json_lookup(attributes, "name", aname))
 			cerror(ctoken, "Duplicated attribute '%s' in NGSI mapping of node '%s'", aname, n->name);
 			
-		json_t *metadatas;
-		json_t *attribute = json_pack("{ s: s, s: s, s: s }",
-			"name",		aname,
-			"type",		atype,
-			"value",	"0"
-		);
+		/* Create Metadata for attribute */
+		json_t *metadatas = json_array();
 
-		metadatas = json_array();
-		json_object_set(attribute, "metadatas", metadatas);
-			
-		/* Metadata */
-		json_array_append(metadatas, json_pack("{ s: s, s: s, s: s }",
+		json_array_append_new(metadatas, json_pack("{ s: s, s: s, s: s }",
 			"name", "source",
 			"type", "string",
 			"value", "s2ss"
 		));
-		json_array_append(metadatas, json_pack("{ s: s, s: s, s: i }",
+		json_array_append_new(metadatas, json_pack("{ s: s, s: s, s: i }",
 			"name", "index",
 			"type", "integer",
 			"value", j
 		));
 
 		if (i->structure == NGSI_CHILDREN) {
-			json_array_append(attributes, json_pack("{ s: s, s: s, s: s }",
+			json_array_append_new(attributes, json_pack("{ s: s, s: s, s: s }",
 				"name", "parentId",
 				"type", "uuid",
 				"value", eid
 			));
 				
-			json_array_append(attributes, json_pack("{ s: s, s: s, s: s }",
+			json_array_append_new(attributes, json_pack("{ s: s, s: s, s: s }",
 				"name", "source",
 				"type", "string",
 				"value", "measurement"
 			));
 			
-			json_array_append(attributes, json_pack("{ s: s, s: s, s: o }",
+			json_array_append_new(attributes, json_pack("{ s: s, s: s, s: o }",
 				"name", "timestamp",
 				"type",	"date",
 				"value", json_date(NULL)
 			));
 		}
 
-		json_array_append(attributes, attribute);
-		i->context_map[j] = attribute;
+		json_t *attribute = i->context_map[j] = json_pack("{ s: s, s: s, s: s }",
+			"name",		aname,
+			"type",		atype,
+			"value",	"0"
+		);
+		
+		json_object_set_new(attribute, "metadatas", metadatas);
+		json_array_append_new(attributes, attribute);
 	}
+	
+	json_object_set_new(i->context, "contextElements", elements);
 }
 
 int ngsi_init(int argc, char *argv[], struct settings *set)
@@ -300,7 +302,7 @@ int ngsi_open(struct node *n)
 	curl_easy_setopt(i->curl, CURLOPT_HTTPHEADER, i->headers);
 	
 	/* Create entity and atributes */
-	json_object_set(i->context, "updateAction", json_string("APPEND"));
+	json_object_set_new(i->context, "updateAction", json_string("APPEND"));
 	return ngsi_request(i->curl, i->context, NULL) == 200 ? 0 : -1;
 }
 
@@ -309,7 +311,7 @@ int ngsi_close(struct node *n)
 	struct ngsi *i = n->ngsi;
 	
 	/* Delete attributes */
-	json_object_set(i->context, "updateAction", json_string("DELETE"));
+	json_object_set_new(i->context, "updateAction", json_string("DELETE"));
 	int code = ngsi_request(i->curl, i->context, NULL) == 200 ? 0 : -1;
 	
 	curl_easy_cleanup(i->curl);
@@ -351,12 +353,12 @@ int ngsi_write(struct node *n, struct msg *pool, int poolsize, int first, int cn
 		json_t *entity, *elements = json_object_get(i->context, "contextElements");
 		size_t ind;
 		json_array_foreach(elements, ind, entity)
-			json_object_set(entity, "id", json_uuid());
+			json_object_set_new(entity, "id", json_uuid());
 		
-		json_object_set(i->context, "updateAction", json_string("APPEND"));
+		json_object_set_new(i->context, "updateAction", json_string("APPEND"));
 	}
 	else
-		json_object_set(i->context, "updateAction", json_string("UPDATE"));
+		json_object_set_new(i->context, "updateAction", json_string("UPDATE"));
 
 	json_t *response;
 	int code = ngsi_request(i->curl, i->context, &response);

From 46bd8a011efda40dafb8efac436cf3ce17e92bb5 Mon Sep 17 00:00:00 2001
From: Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
Date: Mon, 28 Sep 2015 19:16:02 +0200
Subject: [PATCH 10/10] added "deduplication" hook: do not send messages which
 are too similar to their precursors

---
 server/include/config.h |  8 +++++---
 server/include/hooks.h  |  3 +++
 server/src/hooks.c      | 28 ++++++++++++++++++++++++++++
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/server/include/config.h b/server/include/config.h
index 5dec0bcd8..bbd2094f5 100644
--- a/server/include/config.h
+++ b/server/include/config.h
@@ -53,10 +53,12 @@
 	  { "/dev/sda2", "\x53\xf6\xb5\xeb\x8b\x16\x46\xdc\x8d\x8f\x5b\x70\xb8\xc9\x1a\x2a", 0x468 } }
 
 /* Hook function configuration */
-#define HOOK_FIR_INDEX		 1 /**< The first value of message should be filtered. */
-#define HOOK_TS_INDEX		-1 /**< The last value of message should be overwritten by a timestamp. */
-#define HOOK_DECIMATE_RATIO 	30 /**< Only forward every 30th message to the destination nodes. */
+#define HOOK_FIR_INDEX		 1	/**< The first value of message should be filtered. */
+#define HOOK_TS_INDEX		-1	/**< The last value of message should be overwritten by a timestamp. */
+#define HOOK_DECIMATE_RATIO 	30	/**< Only forward every 30th message to the destination nodes. */
 
+#define HOOK_DEDUP_TYPE		HOOK_ASYNC
+#define HOOK_DEDUP_TRESH	1e-3	/**< Do not send messages when difference of values to last message is smaller than this threshold */
 /** Global configuration */
 struct settings {
 	/** Process priority (lower is better) */
diff --git a/server/include/hooks.h b/server/include/hooks.h
index 8cc8094ae..b54e11f82 100644
--- a/server/include/hooks.h
+++ b/server/include/hooks.h
@@ -76,6 +76,9 @@ struct hook {
  * @{
  */
 
+/** Example hook: Drop messages whose values are similiar to the previous ones */
+int hook_deduplicate(struct path *);
+
 /** Example hook: Print the message. */
 int hook_print(struct path *p);
 
diff --git a/server/src/hooks.c b/server/src/hooks.c
index 733d2ba9b..8647c48c7 100644
--- a/server/src/hooks.c
+++ b/server/src/hooks.c
@@ -13,6 +13,7 @@
  *********************************************************************************/
 
 #include <string.h>
+#include <math.h>
 
 #include "timing.h"
 #include "config.h"
@@ -25,6 +26,33 @@
 
 struct list hooks;
 
+REGISTER_HOOK("deduplicate", 99, hook_deduplicate, HOOK_DEDUP_TYPE)
+int hook_deduplicate(struct path *p)
+{
+	int ret = 0;
+#if HOOK_DEDUP_TYPE == HOOK_ASYNC
+	/** Thread local storage (TLS) is used to maintain a copy of the last run of the hook */
+	static __thread struct msg previous = MSG_INIT(0);
+	struct msg *prev = &previous;
+#else
+	struct msg *prev = p->previous;
+#endif
+	struct msg *cur = p->current;
+	
+	for (int i = 0; i < MIN(cur->length, prev->length); i++) {
+		if (fabs(cur->data[i].f - prev->data[i].f) > HOOK_DEDUP_TRESH)
+			goto out;
+	}
+	
+	ret = -1; /* no appreciable change in values, we will drop the packet */
+
+out:
+#if HOOK_DEDUP_TYPE == HOOK_ASYNC
+	memcpy(prev, cur, sizeof(struct msg)); /* save current message for next run */
+#endif
+	return ret;
+}
+
 REGISTER_HOOK("print", 99, hook_print, HOOK_MSG)
 int hook_print(struct path *p)
 {