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"Are you P4 compliant ?". In France in the 1990's it was a pure French private joke before the military service was officially abolished. At that time being "classé P4" meant that you were mentally unable to join the French military army. Even if you wanted to. Therefore, at the age of 18, some daring people faked mental illness in order to avoid the "Service militaire" (1 year duration). Of course here, P4 is about the data plane programming language from P4Lang project.

Requirement

  • Basic Linux/Unix knowledge
  • Basic networking knowledge

Overview

For those who are not familiar with data plane programming and especially with P4, "P4 is a domain-specific programming language for specifying the behaviour of the dataplanes of network-forwarding elements." (from p4.org) in short it helps you to write a "program specifying how a switch processes packets".

Article objective

In this article we'll using freeRouter setup deployed in #002 and replace the pcapInt providing freeRouter native software dataplane with P4Lang's dataplane. Actually the effective dataplane is ensured P4lang virtual simple_switch_grpc running RARE P4 program called: router.p4.

Diagram

[

...

#003 ] - Cookbook

Expand
titleInstall your favorite operating system

In our example we will use the same debian stable image (buster) installed as a VirtualBox VM as in #002.

and we add a bridge network interface to or laptop RJ45 connection.

...

Expand
titleInstall freeRouter net-tools


Code Block
languagebash
themeMidnight
titleget freeRouter net-tools tarball
wget dlfreerouter.nop.hu/rtr.tar


Code Block
languagebash
themeMidnight
titleInstall build tools
tar xvf rtr.tar -C ~/freeRouter/bin/


Note

For those you would like to rebuild these binaries you can find the compilation shell script in freeRouter cloned git repository in: ~/freeRouter/src/native/c.sh


...

Expand
titleLaunch freeRouter control plane along side BMv2 P4 dataplane
Expand
titleCheck telnet access for freerouter@2323


Code Block
languagebash
themeMidnight
titleSetup BMv2 P4 dataplane communication channel via veth pair
sudo ip link add veth251 type veth peer name veth250
sudo ip link set veth250 up  
sudo ip link set veth251 up


Code Block
languagebash
themeMidnight
titlefreeRouter launch with supplied p4-freerouter-hw.txt and p4-freerouter-sw.txt with a console prompt
╭─[6:06:13]floui@debian ~/freeRouter  
╰─➤  java -jar lib/rtr.jar routersc etc/p4-freerouter-hw.txt etc/p4-freerouter-sw.txt
info cfg.cfgInit.doInit:cfgInit.java:556 booting
info cfg.cfgInit.doInit:cfgInit.java:680 initializing hardware
info cfg.cfgInit.doInit:cfgInit.java:687 applying defaults
info cfg.cfgInit.doInit:cfgInit.java:695 applying configuration
info cfg.cfgInit.doInit:cfgInit.java:721 done
welcome
line ready
freerouter#


Code Block
languagebash
themeMidnight
titlelaunch freeRouter pcapInt in order to stitch control plane and P4 BMv2 dataplane communication
╭─[1:00:53]floui@debian[1]  ~/freeRouter/bin  
╰─➤  sudo ./pcapInt.bin veth251 22709 127.0.0.1 22710 127.0.0.1
binded to local                                       3 ↵
info cfg.cfgInit.doInit:cfgInit.java:556 booting
info cfg.cfgInit.doInit:cfgInit.java:680 initializing hardware
info cfg.cfgInit.doInit:cfgInit.java:687 applying defaults
info cfg.cfgInit.doInit:cfgInit.java:695 applying configuration
info cfg.cfgInit.doInit:cfgInit.java:721 done
welcome
line ready
freerouter#
Code Block
languagebash
themeMidnight
titlelaunch freeRouter pcapInt in order to stitch control plane and P4 BMv2 dataplane communication
╭─[1:00:53]floui@debian[1]  ~/freeRouter/bin  
╰─➤  sudo ./pcapInt.bin veth251 22709 127.0.0.1 22710 127.0.0.1                                                                                                      1 ↵
binded to local port 127.0.0.1 22709.
will send to 127.0.0.1 22710.
pcap version: libpcap version 1.8.1
opening interface veth251 with pcap1.x api
serving others
>
Code Block
languagebash
themeMidnight
titleRun RARE P4 dataplane - simple_switch_grpc router.p4 
export P4_RARE_ROOT=/home/floui/RARE/export P4_RARE_ROOT=/home/floui/RARE/02-PE-labs
sudo simple_switch_grpc --log-file $P4_RARE_ROOT/run/log/p4-freerouter.log \                                               
                        -i 1@enp0s9 \                        
                        -i 64@veth250 \                                                
                        --thrift-port 9090 --nanolog ipc://$P4_RARE_ROOT/run/bm-0-log.ipc --device-id 0 $P4_RARE_ROOT/build/simple_switch_grpc.json \
                        -- --grpc-server-addr 127.0.0.1:50051 > $P4_RARE_ROOT/run/log/p4-freerouter.out 2>&1 &                  
port 127.0.0.1 22709.
will send to 127.0.0.1 22710.
pcap version: libpcap version 1.8.1
opening interface veth251 with pcap1.x api
serving others
>


Code Block
languagebash
themeMidnight
titleLaunch forwarder.p4 (p4runtime GRPC based interface)Run RARE P4 dataplane - simple_switch_grpc router.p4 
export P4_RARE_ROOT=/home/floui╭─[2:07:10]floui@debian[1]  ~/RARE/02-PE-labs/p4src  ‹master*› 
╰─➤  ./forwarder.py 
sudo simple_switch_grpc --log-file $P4_RARE_ROOT/run/log/p4-freerouter.log \                                               
                        -i 1@enp0s9 \                        
                                  -i 64@veth250 \              1 ↵
rx:  ['myaddr4_add', '224.0.0.0/4', '0', '1', '\n']
rx:  ['myaddr4_add', '255.255.255.255/32', '0', '1', '\n']
rx:  ['myaddr6_add', 'ff00::/8', '0', '1', '\n']
rx:  ['myaddr4_add', '192.168.1.0/24', '-1', '1', '\n']
rx:  ['myaddr4_add', '192.168.1.131/32', '-1', '1', '\n']
rx:  ['myaddr6_add', 'fd7d:a59c:650b::/60', '-1', '1', '\n']
rx:  ['myaddr6_add', 'fd7d:a59c:650b::666/128', '-1', '1', '\n']
rx:  ['myaddr6_add', 'fe80::/64', '-1', '1', '\n']
rx:  ['mylabel6_add', '270549', '1', '\n']
rx:  ['mylabel4_add', '606864', '1', '\n']
rx:  ['state', '1', '1', '0', '\n']
rx:  ['mtu', '1', '9000', '\n']
rx:  ['portvrf_add', '1', '1', '\n']
rx:  ['neigh4_add', '14252', '192.168.1.1', '34:ce:00:67:18:c2', '1', '00:72:3e:18:1b:6f', '1', '\n']
rx:  ['neigh4_add', '52194', '192.168.1.143', '9c:eb:e8:d5:2c:51', '1', '00:72:3e:18:1b:6f', '1', '\n']
rx:  ['keepalive', '\n']
rx:  ['keepalive', '\n']
...

Verification

                     
                        --thrift-port 9090 --nanolog ipc://$P4_RARE_ROOT/run/bm-0-log.ipc --device-id 0 $P4_RARE_ROOT/build/simple_switch_grpc.json \
                        -- --grpc-server-addr 127.0.0.1:50051 > $P4_RARE_ROOT/run/log/p4-freerouter.out 2>&1 &


Code Block
languagebash
themeMidnight
titleFreeRouter telnet access from Virtualbox VM guest via port 2323Launch forwarder.p4 (p4runtime GRPC based interface)
╭─[72:07:4110]floui@debian[1]  ~/freeRouter/etc  /RARE/02-PE-labs/p4src  ‹master*› 
╰─➤  ./forwarder.py
rx:  ['myaddr4_add', '224.0.0.0/4', '0', '1', '\n']
rx:  ['myaddr4_add', '255.255.255.255/32', '0', '1', '\n']
rx:  ['myaddr6_add', 'ff00::/8', '0', '1', '\n']
rx:  ['myaddr4_add', '192.168.1.0/24', '-1', '1', '\n']
rx:  ['myaddr4_add', '192.168.1.131/32', '-1', '1', '\n']
rx:  ['myaddr6_add', 'fd7d:a59c:650b::/60', '-1', '1', '\n']
rx:  ['myaddr6_add', 'fd7d:a59c:650b::666/128', '-1', '1', '\n']
rx:  ['myaddr6_add', 'fe80::/64', '-1', '1', '\n']
rx:  ['mylabel6_add', '270549', '1', '\n']
rx:  ['mylabel4_add', '606864', '1', '\n']
rx:  ['state', '1', '1', '0', '\n']
rx:  ['mtu', '1', '9000', '\n']
rx:  ['portvrf_add', '1', '1', '\n']
rx:  ['neigh4_add', '14252', '192.168.1.1', '34:ce:00:67:18:c2', '1', '00:72:3e:18:1b:6f', '1', '\n']
rx:  ['neigh4_add', '52194', '192.168.1.143', '9c:eb:e8:d5:2c:51', '1', '00:72:3e:18:1b:6f', '1', '\n']
rx:  ['keepalive', '\n']
rx:  ['keepalive', '\n']
...


Verification

Expand
titleCheck telnet access for freerouter@2323


Code Block
languagebash
themeMidnight
titleFreeRouter telnet access from Virtualbox VM guest via port 2323
╭─[7:07:41]floui@debian[1]  ~/freeRouter/etc  
╰─➤  telnet localhost 2323telnet localhost 2323                                                                                                                                           1 ↵
Trying ::1...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
welcome
line ready
freerouter#


...

Expand
titleConnectivity IPv4/IPv6 check for freeRouter


Code Block
languagebash
themeMidnight
titlePing IPv4 from freerouter -> LAN router gateway
p4-freerouter#ping 192.168.1.131 /vrf v1                                       
pinging 192.168.1.131, src=null, cnt=5, len=64, tim=1000, ttl=255, tos=0, sweep=false
!!!!!
result=100%, recv/sent/lost=5/5/0, rtt min/avg/max/total=0/0/0/0
p4-freerouter#ping 192.168.1.1 /vrf v1                                         
pinging 192.168.1.1, src=null, cnt=5, len=64, tim=1000, ttl=255, tos=0, sweep=false
!!!!!
result=100%, recv/sent/lost=5/5/0, rtt min/avg/max/total=3/5/10/28


Code Block
languagebash
themeMidnight
titleIPv4 arp check ( 192.168.1.1 is the gateway, 192.168.1.143 is the VM host)
p4-freerouter#sh ipv4 arp sdn1                                                 
mac             address        time      static
34ce.0067.18c2  192.168.1.1    00:00:35  false
9ceb.e8d5.2c51  192.168.1.143  00:00:35  false
6420.0c65.437b  192.168.1.173  00:01:35  false

Code Block
languagebash
themeMidnight
titlePing IPv6 from freerouter -> LAN router gateway
p4-freerouter#ping fd7d:a59c:650b::666 /vrf v1                                 
pinging fd7d:a59c:650b::666, src=null, cnt=5, len=64, tim=1000, ttl=255, tos=0, sweep=false
!!!!!
result=100%, recv/sent/lost=5/5/0, rtt min/avg/max/total=0/0/0/1
p4-freerouter#ping fd7d:a59c:650b::1 /vrf v1                                   
pinging fd7d:a59c:650b::1, src=null, cnt=5, len=64, tim=1000, ttl=255, tos=0, sweep=false
!!!!!
result=100%, recv/sent/lost=5/5/0, rtt min/avg/max/total=2/2/3/13


Code Block
languagebash
themeMidnight
titleIPv6 neighbor discovery check ( 192.168.1.1 is the gateway, 192.168.1.143 is the VM host)
p4-freerouter#show ipv6 neighbors sdn1                                         
mac             address                    time      static  router
34ce.0067.18c2  fd7d:a59c:650b::1          00:01:22  false   false
9ceb.e8d5.2c51  fe80::10e6:87a7:6a9:f14a   00:01:22  false   false
34ce.0067.18c2  fe80::36ce:ff:fe67:18c2    00:01:22  false   false
b6be.fdcf.d0f9  fe80::b4be:fdff:fecf:d0f9  00:01:22  false   false


Code Block
languagebash
themeMidnight
titleInitiate IPv4 ssh from freerouter -> LAN router gateway
p4-freerouter#ssh 192.168.1.1 /vrf v1 /user root                               
 - connecting to 192.168.1.1 22
password: ***************
                
 - securing connection



BusyBox v1.28.4 () built-in shell (ash)

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 -----------------------------------------------------
 OpenWrt 18.06.2, r7676-cddd7b4c77
 -----------------------------------------------------
root@OpenWrt:~#


Code Block
languagebash
themeMidnight
titleInitiate IPv6 ssh from freerouter -> LAN router gateway
p4-freerouter#ssh fd7d:a59c:650b::1 /vrf v1 /user root                         
 - connecting to fd7d:a59c:650b::1 22
password: ***************
                
 - securing connection



BusyBox v1.28.4 () built-in shell (ash)

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 -----------------------------------------------------
 OpenWrt 18.06.2, r7676-cddd7b4c77
 -----------------------------------------------------


Conclusion

In this article you:

  • had a demonstration of how to integrate freeRouter into a local area network (Similar to article #002)
  • However instead of using pcapInt you are now using a software P4 dataplane from P4lang project: bmv2 
  • BMv2 simple_switch_grpc target is used an run RARE router.p4
  • communication between freeRouter control plane and bmv2 is ensured by pcapInt via veth pair [ veth250 - veth251 ]
  • This communication is possible via RARE forwarder.py based on GRPC P4Lang P4Runtime python binding
  • In this example the bmv2 BMv2 P4 switch has only 1 dataplane interface that is bound to enp0s9 VM interface expose exposed to the local network as a bridged interface
Tip
title[ #002 #003 ] RARE/FreeRouter-101 - key take-away
  • FreeRouter is using UNIX socket in order to forward packet dedicated to control plane + dataplane communication.

This essential paradigm is used to ensure communication between freeRouter and BMv2 P4 dataplane. It is ensured by pcapInt binary from freeRouter net-tools that will bind freeRouter socket (veth251@locathost:22710) to a virtual network interface (veth250@localhost:22709)  connected to CPU_PORT 64.

  • freeRouter control plane and dataplane communication is enabled by RARE forwarder.py py 

forwarder.py is a simple python script based on GRPC P4Runtime pythonl python library.

freeRouter is doing all the control plane route computation and write/modify/remove message entry via P4Runtime so that P4 entries are created/modified/removed accordingly from P4 tables

While BMv2 target is a very good choice for packet processing algorithm validation, it is not an ideal target for production use. We will see in next articles how we can reach a higher rate throughput related required by the use cases defined by network operators.  

...