media/cast/test/utility/shadow.sh

   1 #!/bin/sh
   2 # Copyright 2014 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5 #
   6 # The purpose of this script is to set up all the neccessary magic to
   7 # pipe network traffic through a user-space process. That user-space
   8 # process can then delay, reorder and drop packets as it pleases to
   9 # emulate various network environments.
  10 #
  11 # The script currently assumes that you communicate with your cast streaming
  12 # receiver through eth1. After running "shadow.sh start", your network will
  13 # look something like this:
  14 #
  15 #              +--------------------------------------------------+
  16 #              |            Your linux machine                    |
  17 #              | +---------------+                                |
  18 # cast         | |shadowbr bridge|               +-------------+  |
  19 # streaming <--+-+---> eth1      |               |routing table|  |
  20 # receiver     | |     tap2  <---+-> tap_proxy <-+-> tap1      |  |
  21 #              | |  +->veth      |               |   eth0 <----+--+->internet
  22 #              | +--+------------+               |   lo        |  |
  23 #              |    |                            +-------------+  |
  24 #              |    |      +------------------+       ^           |
  25 #              |    |      |shadow container  |       |           |
  26 #              |    +------+-->veth           |     chrome        |
  27 #              |           | netload.py server|  netload.py client|
  28 #              |           +------------------+                   |
  29 #              +--------------------------------------------------+
  30 #
  31 # The result should be that all traffic to/from the cast streaming receiver
  32 # will go through tap_proxy. All traffic to/from the shadow container
  33 # will also go through the tap_proxy. (A container is kind of like a
  34 # virtual machine, but more lightweight.) Running "shadow.sh start" does
  35 # not start the tap_proxy, so you'll have to start it manually with
  36 # the command "tap_proxy tap1 tap2 <network_profile>" where
  37 # <network_profile> is one of "perfect", "good", "wifi", "bad" or "evil".
  38 #
  39 # While testing mirroring, we can now generate TCP traffic through
  40 # the tap proxy by talking to the netload server inside the "shadow"
  41 # container by using the following command:
  42 #
  43 # $ netload.py upload IP PORT
  44 #
  45 # The IP and PORT are printed out by this script when you run
  46 # "shadow.sh start", but will generally be the *.*.*.253 address
  47 # of the eth1 network, so hopefully that's not already taken...
  48
  49 set -x
  50
  51 DEV=eth1
  52 TAP1=tap1
  53 TAP2=tap2
  54
  55 IP="$(ifconfig $DEV | sed -n 's@.*inet addr:\([^ ]*\).*@\1@gp')"
  56 MASK="$(ifconfig $DEV | sed -n 's@.*Mask:\([^ ]*\).*@\1@gp')"
  57 BCAST="$(ifconfig $DEV | sed -n 's@.*Bcast:\([^ ]*\).*@\1@gp')"
  58 NET=$(route -n | grep $DEV | head -1 | awk '{print $1}')
  59 DIR=$(dirname "$0")
  60
  61 case "$MASK" in
  62   255.255.255.0) MASK_BITS=24 ;;
  63   255.255.0.0) MASK_BITS=16 ;;
  64   255.0.0.0) MASK_BITS=8 ;;
  65   *)
  66     echo "Unknown network mask"
  67     exit 1
  68   ;;
  69 esac
  70
  71 SHADOWIP="$(echo $IP | sed 's@[^.]*$@@g')253"
  72 SHADOWCONF="/tmp/shadowconf.$$"
  73 cat <<EOF >$SHADOWCONF
  74 lxc.utsname = shadow
  75 lxc.network.type = veth
  76 lxc.network.link = shadowbr
  77 lxc.network.flags = up
  78 lxc.network.ipv4 = $SHADOWIP/$MASK_BITS
  79 lxc.network.ipv4.gateway = $IP
  80 lxc.kmsg = 0
  81 EOF
  82
  83 trap "rm $SHADOWCONF" SIGINT SIGTERM EXIT
  84 LXC_COMMON="-n shadow -f $SHADOWCONF"
  85
  86 case "$1" in
  87   start)
  88     openvpn --mktun --dev $TAP1
  89     openvpn --mktun --dev $TAP2
  90     ifconfig $TAP1 $IP netmask $MASK broadcast $BCAST up
  91     ifconfig $TAP2 up
  92     route add -net $NET netmask $MASK $TAP1
  93     brctl addbr shadowbr
  94     brctl addif shadowbr $TAP2 $DEV
  95     ifconfig shadowbr up
  96     lxc-create $LXC_COMMON
  97     lxc-execute $LXC_COMMON -- \
  98        "$DIRNAME/netload.py listen 9999" >/dev/null </dev/null 2>&1 &
  99     echo "Now run: tap_proxy $TAP1 $TAP2 wifi"
 100     echo "Data sink/source is available on $SHADOWIP 9999"
 101   ;;
 102
 103   stop)
 104     lxc-kill -n shadow
 105     sleep 1
 106     lxc-destroy $LXC_COMMON
 107     ifconfig $TAP1 down
 108     ifconfig $TAP2 down
 109     ifconfig shadowbr down
 110     brctl delbr shadowbr
 111     openvpn --rmtun --dev $TAP1
 112     openvpn --rmtun --dev $TAP2
 113   ;;
 114
 115   *)
 116     echo "$0 start/stop"
 117     echo "Read $0 for more information."
 118   ;;
 119 esac
 120
 121