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PiRYU README File - Li Lin(also inline)

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1
2
3OpenFlow on RPi
4Li Lin, Regina Hain
5
6The goal of this work is to run an OpenFlow controller on a raspberry pi.
7To do so, we used Open vSwitch to configure the virtual switches on the
8pi server and Ryu to run the controller and to inject custom flows.
9
10There are three major pieces of this project:
111. Use OVS to setup a useful and interesting network
122. Run a custom script with the Ryu controller to install flows and route packets
133. Demoing the system with a streaming webcam application
14
15==Part I: Using OVS to set up a useful and interesting network==
16
17=Topology=
18 _______________________________________________________________________       
19|Pi Server                                                              |
20|   ____________         _______________         _______________        |
21|  |    BR1     |       |     BR2       |       |     BR3       |       |
22|  |  10.10.1.1 |  PP*  |   10.10.2.1   |  PP*  |  10.10.3.1    |       |
23|  |           2|-------|2             3|-------|2              |       |
24|  |_____1______|       |______1________|       |______1________|       |
25|   _____|______         ______|________         ______|________        |
26|  |eth1        |       |eth2           |       |eth3           |       |
27|  |10.10.1.x   |       |10.10.2.x      |       |10.10.3.x      |       |
28|  |____________|       |_______________|       |_______________|       |
29|        |                     |                       |                |
30|        |                     |                       |                |
31|________|_____________________|_______________________|________________|
32         |                     |                       |
33    _____|______         ______|________         ______|________       
34   |    Pi1     |       |     Pi2       |       |     Pi3       |
35   | 10.10.1.2  |       |  10.10.2.2    |       |  10.10.3.2    |
36   |____________|       |_______________|       |_______________|
37
38
39*: PP means patch port
40
41=Description=
42This setup consists of 4 pi's- one acting as a server 3 as the clients.
43There are 3 accompanying interfaces on the server- eth1, eth2, eth3, each
44their own subnet. Additionally, each is connected to a separate OVS bridge.
45The OVS bridges forward packets to all other bridges via patch ports.
46
47=Setup on server=
48To configure this network, run configure_pt1
49
50=Setup on client=
51To configure the ip address of client pi's, add the following
52lines to /etc/dhcpcd.conf depending on its ip address and router values
53
54# In pi1 /etc/dhcpcd.conf
55interface eth0
56static ip_address=10.10.1.2/24
57static router=10.10.1.1
58
59# In pi2 /etc/dhcpcd.conf
60interface eth0
61static ip_address=10.10.2.2/24
62static router=10.10.2.1
63
64# In pi3 /etc/dhcpcd.conf
65interface eth0
66static ip_address=10.10.3.2/24
67static router=10.10.3.1
68
69=Test=
70To test, run ping from one client Pi to another client Pi. Connectivity
71should be present, via the OVS bridge and patch port topology, between
72all three client Pi's.
73
74=Teardown=
75To teardown this network, run teardown_pt1
76
77
78==Part II: Using Ryu to install flows and route packets over our OVS network==
79
80=Topology=
81 _______________________________________________________________________
82|Pi Server                                                              |
83|   ____________________________________________________________        |
84|  |                            BR1                             |       |
85|  |                         10.10.1.10                         |       |
86|  |                                                            |       |
87|  |_____1_____________________3_______________________2________|       |
88|   _____|______         ______|________         ______|________        |
89|  |eth1        |       |eth2           |       |eth3           |       |
90|  |10.10.1.1   |       |10.10.1.3      |       |10.10.1.2      |       |
91|  |____________|       |_______________|       |_______________|       |
92|        |                     |                       |                |
93|        |                     |                       |                |
94|________|_____________________|_______________________|________________|
95         |                     |                       |
96    _____|______         ______|________         ______|________
97   |    Pi1     |       |     Pi2       |       |     Pi3       |
98   | 10.10.1.4  |       |  10.10.1.5    |       |  10.10.1.6    |
99   |____________|       |_______________|       |_______________|
100
101Note that this topology is different from that in part I. This is because
102having 3 bridges added too much unneeded complexity when crafting custom
103flows. This time we used 1 bridge to connect all three interfaces and
104connecting them up through separate ports.
105
106=RYU Script Description=
107
108This script creates a custom flow that matches on any packet coming in
109on port 1 (source 10.10.1.4) and out on port 3 (destination 10.10.1.5).
110It forwards that packet as usual, but also
111creates a duplicate packet, modifies its destination (to the address
112of pi3) and sends to port 2 (pi 3). The result is that pi3 gets a copy
113of every packet that is sent from pi1 to pi2.
114
115Note that to turn on the special flow, *insert_special_flow* must be set to
116True in ryu_13_custom.py
117
118To see that the custom flow is installed correctly (note that installation
119will occur only on the first instance of a packet with source 10.10.1.4
120and destination 10.10.1.5 captured by our controller), on the server type
121$ sudo ovs-ofctl dump-flows br1
122
123=Setup=
124To configure this network, run configure_pt2
125Note that step 5, connecting the controller to the bridge, takes the
126ip address of the server's eth0 interface. This can change based on
127network and pi. To find the correct ip address to use, in a terminal type
128$ ifconfig -a
129
130=Run=
131To run the ryu controller with our custom script type:
132$ ryu-manager ./path/to/ryu_13_custom.py
133To ensure controller connectivity type:
134$ sudo ovs-vsctl show
135and you should see something like this (if connected):
136    Bridge "br1"
137        Controller "tcp:128.89.68.110:6633"
138            is_connected: true
139
140=Testing=
141
142Ping test
143On 10.10.1.4 (pi1) type
144$ ping 10.10.1.5
145You will see that 2 different hosts will reply to the pings- both
146pi2 (10.10.1.5) and pi3 (10.10.1.6).
147
148Netcat test
149On 10.10.1.5 (pi2) type
150$ nc -l 1234
151On 10.10.1.6 (pi3) type
152$ nc -l 1234
153On 10.10.1.4 (pi1) type
154$ echo "HELLO WORLD" | nc 10.10.1.5 1234 -u
155
156You should see that HELLO WORLD should be printed on both pi2 and pi3.
157This only works in udp mode (-u) and the reason is left as an
158exercise for the reader.
159
160=Teardown=
161To teardown this network, run teardown_pt2
162
163
164==Part III: Demoing via a streaming webcam application==
165
166In this demo, pi1 (10.10.1.4) will send raw video bytes captured from
167its webcam to pi2 (10.10.1.5) via the netcat application. Pi2 will capture
168the udp packets by using netcat to listen on a specified port and save
169the data to a pipe file. Pi2 will then run mplayer on the file to output the
170video to screen. Pi3 will perform the same exact functions as Pi2, and
171since the controller sends a duplicate copy of every udp packet to Pi3,
172it can receive and render the webcam video also.
173
174On Pi1:
1751. Compile the C file used to read data from the webcam
176$ gcc capturevideo.c -o capturevideo
1772. Execute and pipe the output to 10.10.1.5 via netcat
178$ ./capturevideo -c 1000 -o | nc 10.10.1.5 5000
179*. Instructions and code taken from: https://www.raspberrypi.org/forums/viewtopic.php?t=98778&p=685576
180
181On Pi2:
1821. If not installed already, install mplayer
183$ sudo apt-get install mplayer
1842. Create a pipe file
185$ mkfifo video.fifo
1863. Call netcat and listen to specified port
187$ nc.traditional -lu -p 5000 > video.fifo
1884. Use mplayer to open video
189$ mplayer video.fifo -demuxer rawvideo -rawvideo w=640:h=480:format=yuy2
190
191On Pi3:
1921. If not installed already, install mplayer
193$ sudo apt-get install mplayer
1942. Create a pipe file
195$ mkfifo video.fifo
1963. Call tcpdump to listen to specified port
197$ sudo tcpdump -i eth0 udp port 5000 -w video.fifo
198Note: Netcat will not accept packets because it requires a connection,
199even when solely listening for udp packets, when the datagram size is over
2001500 bytes.
2014. Use mplayer to open video
202$ mplayer video.fifo -demuxer rawvideo -rawvideo w=640:h=480:format=yuy2
203
204