Simple-P4runtime-Controller

Mininet with simple_switch_grpc

The scripts starts a very simple Mininet topo with just one switch, n hosts and 1 server host. Additionally, it compiles the supplied P4 file to generate both the JSON as well as P4Info file (used by the controller)

usage: run_mininet.py [-h] [--num-hosts NUM_HOSTS] [--p4-file P4_FILE]

Mininet demo

optional arguments:
  -h, --help            show this help message and exit
  --num-hosts NUM_HOSTS
                        Number of hosts to connect to switch
  --p4-file P4_FILE     Path to P4 file

P4Runtime controller

Dummy P4Runtime controller with packet-in/packet-out functionality.

usage: controller.py [-h] [--p4info P4INFO] [--bmv2-json BMV2_JSON]

P4Runtime Controller

optional arguments:
  -h, --help            show this help message and exit
  --p4info P4INFO       p4info proto in text format from p4c
  --bmv2-json BMV2_JSON
                        BMv2 JSON file from p4c

At the start of the connection, the controller installs three rules, forwarding the packets to the CPU port. Furthermore, it listens to PacketIn messages and outputs them to port 3.

Packet-In messages

At the beginning of each packet_in message, a special header containing the ingress port is appended—these values translate to the controller's metadata values.

 @controller_header("packet_in")
 header packet_in_t {
    bit<16> ingress_port;
 }

Packet-Out messages

At the beginning of each packet Out message, a special header containing the egress port is appended. This value is set at the controller (as metadata in the buildPacketOut function)

 @controller_header("packet_in")
 header packet_in_t {
     bit<16> ingress_port;
 }

Run a test scenario

Start Mininet (with simple_switch_grpc)

python3 run_mininet.py --p4-file simple.p4

Start the controller in a different terminal

python3 controller.py --p4info firmeware.p4info.txt --bmv2-json simple.json

Generate traffic (in Mininet)

h1 python UDPsend.py

Observe PacketOut packets on the server

Mininet will create a topology with 2 hosts and 1 server connected to a switch. The controller will for each received packetIn, generate a PacketOut and specify the output port as the 3rd port (hardcoded in the packetOut).

$ sudo tcpdump -i s0-eth3

Expected output:

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on s0-eth3, link-type EN10MB (Ethernet), capture size 262144 bytes
23:03:25.949165 IP 10.10.10.1.7777 > 10.10.3.3.80: UDP, length 24
23:03:25.988292 IP 10.10.10.1.7777 > 10.10.3.3.80: UDP, length 24
23:03:26.033244 IP 10.10.10.1.7777 > 10.10.3.3.80: UDP, length 24
23:03:26.068418 IP 10.10.10.1.7777 > 10.10.3.3.80: UDP, length 24
23:03:26.109795 IP 10.10.10.1.7777 > 10.10.3.3.80: UDP, length 24