A Linux gulp box

gulp-my-box.sh

DEV1=eth4
DEV2=eth5
###########################################################################
# install gulp
###########################################################################
apt-get install libpcap-dev
wget http://staff.washington.edu/corey/gulp/gulp.tgz
mkdir -p gulp
cd gulp && tar xvfz ../gulp.tgz 
make
###########################################################################
# install bridging
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sudo apt-get install bridge-utils
cat << EOF >> /etc/network/interfaces
# Bridge between $DEV1 and $DEV2
auto br0
iface br0 inet dhcp
# For static configuration delete or comment out the above line and uncomment the following:
# iface br0 inet static
#  address 192.168.1.10
#  netmask 255.255.255.0
#  network 192.168.1.0
#  gateway 192.168.1.1
#  dns-nameservers 192.168.1.5
#  dns-search example.com
  pre-up ip link set $DEV1 down
  pre-up ip link set $DEV2 down
  pre-up brctl addbr br0
  pre-up brctl addif br0 $DEV1 $DEV2
  pre-up ip addr flush dev $DEV1
  pre-up ip addr flush dev $DEV2
  post-down ip link set $DEV1 down
  post-down ip link set $DEV2 down
  post-down ip link set br0 down
  post-down brctl delif br0 $DEV1 $DEV2
  post-down brctl delbr bra
EOF
# reboot. Test by putting traffic between eth4 eth5 and tcpdump'ing br0.
###########################################################################
# start gulp on restart
###########################################################################
cat << EOF > /etc/init/gulp.conf
##############################################################################
# XipLink Gulp Appliance
##############################################################################

description "Xiplink Gulp Appliance"

# -i br0 	 = capture interface
# -V xxxxxxxxxx	 = ps status line
# -W 55		 = wrap at 55 files
# -o /home/test	 = output dir to write cap files to

# double check gulp dir and record dir
exec /home/xiplink/gulp/gulp -i br0 -V xxxxxxxxxx -W 55 -o /home/test


respawn
respawn limit 3 12

start on runlevel [345]
start on runlevel [012]

pre-start script
    # prepare environment - ensure matches -o from gulp exec line
    mkdir -p /home/test
end script
EOF
# reboot - takes a bit to start up, may need some refinement with respect to "start on" conditions.

###########################################################################
# monitor script
###########################################################################
cat << EOF > monitor.sh
#!/usr/bin/env python
import subprocess
 
# ifstat rates are in kB/s
thresholdRate = 100.0
refreshInterval = 1
 
if "stop" in subprocess.check_output(["/sbin/status", "gulp"]):
    print "failed to find gulp"
    exit(-12)
 
process = subprocess.Popen(["/usr/bin/ifstat","-n", "-i","br0", refreshInterval], bufsize = 1, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
 
#(stdout, stderr) = process.communicate()
stdout = process.stdout.readline()
if not 'br0' in stdout:
    print "Interface br0 not found in ifstat - " + stdout
    exit(-2)
 
if not "KB/s in" in process.stdout.readline():
    print "Unexpected format from ifstat"
    exit(-2)
 
baselineFound = False
while not baselineFound:
    inrate = process.stdout.readline().split()[0]
    print str(inrate) + " checking low"
    baselineFound = float(inrate) > thresholdRate
baselineLost = False
while not baselineLost:
    try:
        inrate = process.stdout.readline().split()[0]
        print str(inrate) + " checking high"
        baselineLost = float(inrate) < thresholdRate
    except:
        print "error in input - %s - stopping gulp" % inrate
        baselineLost = True
print("br0 rate dropped below %d, killing gulp." % thresholdRate)
process.terminate()
 
 
if subprocess.call(["/sbin/stop", "gulp"]) != 0:
    print "failed to kill gulp"
EOF
###########################################################################
# misc
###########################################################################
# added ifstat to watch traffic levels go through, used in monitor.sh above
# disabled avahi, cups, lightdm