arr2036 · November 26, 2024 14:25 · Jan 17, 2018 · Apr 3, 2014 · Sep 18, 2013 · Sep 18, 2013
diff --git a/delay.sh b/delay.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # root qdisc handle
 r_handle=1
 # netem qdisc handle

diff --git a/delay.sh b/delay.sh
@@ -146,7 +146,7 @@ if [ $qdpresent != true ]; then
 fi
 
 #
-#	Add any IP filters first, these classify the traffic and limit what's delayed
+#	Add any IP filters these classify the traffic and limit what's delayed
 #
 if [ "$dstip" != '' ]; then
 	log "Checking if IP is already in filter... " false

diff --git a/delay.sh b/delay.sh
@@ -195,6 +195,7 @@ if [ "$delay" != '' ]; then
 			log "ok"
 		else
 			log "failed ($?)"
+			exit 1
 		fi
 	else
 		log "yes"

diff --git a/gistfile1.sh → delay.sh b/gistfile1.sh → delay.sh
@@ -108,7 +108,7 @@ fi
 #	let's hope nothing else if using this handle
 #
 log "Checking if root qdisc already added to $interface... " false
-if tc qdisc show dev bebe0 | grep "qdisc prio $r_handle:" > /dev/null; then
+if tc qdisc show dev "$interface" | grep "qdisc prio $r_handle:" > /dev/null; then
 	log "yes"
 	qdpresent=true
 else

diff --git a/gistfile1.sh b/gistfile1.sh
@@ -0,0 +1,202 @@
+#!/bin/sh
+# root qdisc handle
+r_handle=1
+# netem qdisc handle
+n_handle=2 
+
+interface=
+delay=
+dstip=
+qdpresent=
+delete=false
+verbose=false
+
+error() {
+	printf "%s\n" "$1" >&2
+}
+
+log() {
+	if [ $verbose == true ]; then
+		printf "%s" "$1"
+
+		if [ "$2" != false ]; then
+			printf "\n"
+		fi
+	fi
+}
+
+# Ish...
+isip () {
+	if ! echo "$1" | grep -E '([0-9]{1,3}[.]){3}[0-9]{1,3}(/[0-9]{1,2})?' > /dev/null; then
+		return 1 
+	fi
+
+	return 0
+}
+
+iptohex () {
+	printf '%02x' `echo "$1" | sed 's/\./ /g'`
+}
+
+usage() {
+	echo "$0 -i <interface> -d <ip> -m <milliseconds> [start|stop]"
+	exit 1
+}
+
+while getopts ":hi:d:m:v" opt; do
+	case "${opt}" in
+		h)
+			usage
+			;;
+
+		i)
+			interface="${OPTARG}"
+			;;
+
+		d)
+			dstip="${OPTARG}"
+			;;
+
+		m)
+			delay="${OPTARG}"
+			if ! echo "$delay" | grep -E '^[0-9]+$' > /dev/null; then
+				error "-m must be an interger value, got '$delay'"
+				usage
+			fi
+			;;
+
+		v)
+			verbose=true
+			;;
+
+		*)
+			usage
+			;;
+	esac
+done
+shift $((OPTIND-1))
+
+if [ "$interface" == '' ]; then
+	error "No interface specified"
+	usage
+fi
+
+if [ "$1" == 'stop' ]; then
+	delete=true
+elif [ "$1" != 'start' ]; then
+	error "Invalid operation '$1', expected start or stop"
+	usage
+fi
+
+#
+#	Play nice with FQDNs too (IPv4 only)
+#
+if [ "$dstip" != '' ]; then
+	if ! isip "$dstip"; then
+		ret=`host $dstip`
+		rsv=`echo "$ret" | tail -n 1 | grep -o -E '([0-9]{1,3}[.]){3}[0-9]{1,3}'`
+		if [ $? -ne 0 ] || ! isip "$rsv"; then
+			error "Failed resolving $dstip: $ret"
+			exit 1
+		fi
+		dstip=$rsv
+	fi
+fi
+
+#
+#	Check if we have our queue discipline already added to the target inerface
+#	let's hope nothing else if using this handle
+#
+log "Checking if root qdisc already added to $interface... " false
+if tc qdisc show dev bebe0 | grep "qdisc prio $r_handle:" > /dev/null; then
+	log "yes"
+	qdpresent=true
+else
+	log "no"
+	qdpresent=false
+fi
+
+#
+#	Were we told to stop delaying packets?
+#
+if [ $delete == true ]; then
+	if [ $qdpresent == true ]; then
+		log "Removing qdisc with handle $r_handle... " false
+		if tc qdisc del dev "$interface" root handle $r_handle:; then
+			log "ok"
+		else
+			log "failed ($?)"
+			exit 1 
+		fi
+	fi
+	exit 0  
+fi
+
+#
+#	Nope, first add the new root queue discipline if required
+#
+if [ $qdpresent != true ]; then
+	log "Adding qdisc with handle $r_handle... " false
+	if tc qdisc add dev "$interface" root handle $r_handle: prio; then
+		log "ok"
+	else
+		log "failed ($?)"
+		exit 1
+	fi
+fi
+
+#
+#	Add any IP filters first, these classify the traffic and limit what's delayed
+#
+if [ "$dstip" != '' ]; then
+	log "Checking if IP is already in filter... " false
+	if ! tc filter show dev "$interface" parent $r_handle:0 | grep -E 'match.*'`iptohex "$dstip"` > /dev/null; then
+		log "no"
+
+		log "Adding IP $dstip to filter... " false
+
+		# Add a filter to device $interface
+		# - attach it to qdisc $r_handle:0
+		# - apply it to IP packets
+		# - with a prio/pref (priority) of 1 (this is arbitrary as all filters have the same priority)
+		# - use the u32 classifier
+		# - match on ip dst $dstip
+		# - forward matching packets to flowid $n_handle:1
+		if tc filter add dev "$interface" parent $r_handle:0 protocol ip prio 1 u32 match ip dst $dstip flowid $n_handle:1; then
+			log "ok"
+		else
+			log "failed ($?)"
+			exit 1
+		fi
+	else
+		log "yes"
+	fi
+fi
+
+#
+#	This is the destination for the filters we added above
+#
+if [ "$delay" != '' ]; then
+	log "Checking if netem qdisc has been added (and has correct delay)... " false
+	netem=`tc qdisc show dev "$interface" | grep "netem.*$n_handle:"`
+	if [ $? -ne 0 ]; then
+		log "no"
+		log "Adding qdisc netem with handle $n_handle (delay ${delay}ms)... " false
+		if tc qdisc add dev "$interface" parent $r_handle:1 handle $n_handle: netem delay ${delay}ms; then
+			log "ok"
+		else
+			log "failed ($?)"
+			exit 1
+		fi
+	elif ! echo "$netem" | grep "delay ${delay}.*ms" > /dev/null; then
+		log "yes"
+		log "Changing qdisc netem delay to ${delay}ms... " false
+		if tc qdisc change dev "$interface" parent $r_handle:1 handle $n_handle: netem delay ${delay}ms; then
+			log "ok"
+		else
+			log "failed ($?)"
+		fi
+	else
+		log "yes"
+	fi
+fi
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