+### for demos - connect to an ndnmap deployment to visualize links bandwidth
+# this expects 3 arguments
+# an interface name, L<id1>-<id2> based on your ids in conf.mk
+# the hostname for a ndnmap deployment
+# a linkid, this is the id that this link has in your ndnmap scenario (hard-coded in some json file)
+# this one-shot function writes the current statistics onto the ndnmap site
+# it needs to be called regularly so that ndnmap can do the bw computations
+# would make sense for the caller to redirect stderr onto some relevant location
+function gmap_report_once () {
+ iface=$1; shift
+ hostname=$1; shift
+ linkid=$1; shift
+ report=$(ovs-vsctl get interface $iface statistics)
+ rx_bytes=$(echo $report | sed -e 's/^.*rx_bytes=//' -e 's/,.*$//')
+ tx_bytes=$(echo $report | sed -e 's/^.*tx_bytes=//' -e 's/,.*$//')
+ rx_bits=$(($rx_bytes*8))
+ tx_bits=$(($tx_bytes*8))
+ now=$(date +%s).$(date +%N)
+ trigger=http://${hostname}/bw/${linkid}/${now}/${rx_bits}/${tx_bits}
+# curl -s -L $trigger | grep -q "Got it" || echo Missed event with $trigger
+# echo $trigger
+ curl -s -L $trigger >& /dev/null
+}
+
+### the front end, manages pid and so on
+function gmap_report () {
+ iface=$1; shift
+ hostname=$1; shift
+ linkid=$1; shift
+ looptime=$1; shift
+ [ -z "$looptime" ] && looptime=1
+# we'd need a means to avoid running 2 instances at the same time
+# but it's kind of hard to keep track of the right pid here..
+# pidfile=/var/run/openvswitch/gmap-$iface.pid
+# if [ -f $pidfile ] ; then
+# pid=$(cat $pidfile)
+# [ -n "$pid" ] && kill $pid
+# rm $pidfile
+# fi
+ while true; do
+# echo $$ > $pidfile
+ gmap_report_once $iface $hostname $linkid
+ sleep $looptime
+ done
+}
+