P4 (P4-16) Switch: Meter Example

H1(10.0.0.1,00:00:00:00:00:01)---s1---H2(10.0.0.2,00:00:00:00:00:02)

We will set a meter for the traffic that is destined to H2 (00:00:00:00:00:02).

[basic.p4]

/* -*- P4_16 -*- */

#include <core.p4>

#include <v1model.p4>

const bit<16> TYPE_IPV4 = 0x800;

/*************************************************************************

*********************** H E A D E R S ***********************************

*************************************************************************/

typedef bit<9> egressSpec_t;

typedef bit<48> macAddr_t;

typedef bit<32> ip4Addr_t;

header ethernet_t {

macAddr_t dstAddr;

macAddr_t srcAddr;

bit<16> etherType;

}

header ipv4_t {

bit<4> version;

bit<4> ihl;

bit<8> diffserv;

bit<16> totalLen;

bit<16> identification;

bit<3> flags;

bit<13> fragOffset;

bit<8> ttl;

bit<8> protocol;

bit<16> hdrChecksum;

ip4Addr_t srcAddr;

ip4Addr_t dstAddr;

}

struct metadata {

bit<32> meter_tag;

}

struct headers {

ethernet_t ethernet;

ipv4_t ipv4;

}

/*************************************************************************

*********************** P A R S E R ***********************************

*************************************************************************/

parser MyParser(packet_in packet,

out headers hdr,

inout metadata meta,

inout standard_metadata_t standard_metadata) {

state start {

transition parse_ethernet;

}

state parse_ethernet {

packet.extract(hdr.ethernet);

transition select(hdr.ethernet.etherType) {

TYPE_IPV4: parse_ipv4;

default: accept;

}

}

state parse_ipv4 {

packet.extract(hdr.ipv4);

transition accept;

}

}

/*************************************************************************

************ C H E C K S U M V E R I F I C A T I O N *************

*************************************************************************/

control MyVerifyChecksum(inout headers hdr, inout metadata meta) {

apply { }

}

/*************************************************************************

************** I N G R E S S P R O C E S S I N G *******************

*************************************************************************/

control MyIngress(inout headers hdr,

inout metadata meta,

inout standard_metadata_t standard_metadata) {

meter(10, MeterType.packets) my_meter;

action drop() {

mark_to_drop();

}

action forward(egressSpec_t port) {

standard_metadata.egress_spec = port;

}

action m_action(bit<32> meter_idx) {

my_meter.execute_meter((bit<32>)meter_idx, meta.meter_tag);

}

action set_tos(bit<8> tos) {

hdr.ipv4.diffserv=tos;

}

table phy_forward {

key = {

standard_metadata.ingress_port: exact;

}

actions = {

forward;

drop;

}

size = 1024;

default_action = drop();

}

table m_table {

key = {

hdr.ethernet.dstAddr: exact;

}

actions = {

m_action;

NoAction;

}

size = 1024;

default_action = NoAction();

}

table m_filter {

key = {

meta.meter_tag: exact;

}

actions = {

set_tos;

drop;

NoAction;

}

size = 1024;

default_action = drop();

}

apply {

phy_forward.apply();

m_table.apply();

m_filter.apply();

}

}

/*************************************************************************

**************** E G R E S S P R O C E S S I N G *******************

*************************************************************************/

control MyEgress(inout headers hdr,

inout metadata meta,

inout standard_metadata_t standard_metadata) {

apply { }

}

/*************************************************************************

************* C H E C K S U M C O M P U T A T I O N **************

*************************************************************************/

control MyComputeChecksum(inout headers hdr, inout metadata meta) {

apply {

update_checksum(

hdr.ipv4.isValid(),

{ hdr.ipv4.version,

hdr.ipv4.ihl,

hdr.ipv4.diffserv,

hdr.ipv4.totalLen,

hdr.ipv4.identification,

hdr.ipv4.flags,

hdr.ipv4.fragOffset,

hdr.ipv4.ttl,

hdr.ipv4.protocol,

hdr.ipv4.srcAddr,

hdr.ipv4.dstAddr },

hdr.ipv4.hdrChecksum,

HashAlgorithm.csum16);

}

}

/*************************************************************************

*********************** D E P A R S E R *******************************

*************************************************************************/

control MyDeparser(packet_out packet, in headers hdr) {

apply {

packet.emit(hdr.ethernet);

packet.emit(hdr.ipv4);

}

}

/*************************************************************************

*********************** S W I T C H *******************************

*************************************************************************/

V1Switch(

MyParser(),

MyVerifyChecksum(),

MyIngress(),

MyEgress(),

MyComputeChecksum(),

MyDeparser()

) main;

[test_topo.py]

import os

from mininet.net import Mininet

from mininet.topo import Topo

from mininet.log import setLogLevel, info

from mininet.cli import CLI

from mininet.node import RemoteController

from p4_mininet import P4Switch, P4Host

import argparse

from time import sleep

parser = argparse.ArgumentParser(description='Mininet demo')

parser.add_argument('--behavioral-exe', help='Path to behavioral executable',

type=str, action="store", required=False, default='simple_switch' )

parser.add_argument('--thrift-port', help='Thrift server port for table updates',

type=int, action="store", default=9090)

parser.add_argument('--num-hosts', help='Number of hosts to connect to switch',

type=int, action="store", default=2)

parser.add_argument('--mode', choices=['l2', 'l3'], type=str, default='l3')

parser.add_argument('--json', help='Path to JSON config file',

type=str, action="store", required=True)

parser.add_argument('--pcap-dump', help='Dump packets on interfaces to pcap files',

type=str, action="store", required=False, default=False)

args = parser.parse_args()

class SingleSwitchTopo(Topo):

def __init__(self, sw_path, json_path, thrift_port, pcap_dump, **opts):

Topo.__init__(self, **opts)

switch1 = self.addSwitch('s1', sw_path = sw_path, json_path = json_path, thrift_port = thrift_port,cls = P4Switch ,pcap_dump = pcap_dump)

host1 = self.addHost('h1', mac = '00:00:00:00:00:01')

host2 = self.addHost('h2', mac = '00:00:00:00:00:02')

self.addLink(host1, switch1, port1 = 0, port2 = 1)

self.addLink(host2, switch1, port1 = 0, port2 = 2)

def main():

topo = SingleSwitchTopo(args.behavioral_exe, args.json, args.thrift_port, args.pcap_dump)

net = Mininet(topo = topo, host = P4Host, controller = None)

net.start()

sleep(1)

print('\033[0;32m'),

print "Gotcha!"

print('\033[0m')

CLI(net)

try:

net.stop()

except:

print('\033[0;31m'),

print('Stop error! Trying sudo mn -c')

print('\033[0m')

os.system('sudo mn -c')

print('\033[0;32m'),

print ('Stop successfully!')

print('\033[0m')

if __name__ == '__main__':

setLogLevel('info')

main()

[start_test_topo.py]

import os

os.system("sudo python test_topo.py --behavioral-exe /home/vagrant/behavioral-model/targets/simple_switch/simple_switch --json basic.json")

[p4_mininet.py]

# Copyright 2013-present Barefoot Networks, Inc.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

# http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

#

from mininet.net import Mininet

from mininet.node import Switch, Host

from mininet.log import setLogLevel, info, error, debug

from mininet.moduledeps import pathCheck

from sys import exit

import os

import tempfile

import socket

class P4Host(Host):

def config(self, **params):

r = super(Host, self).config(**params)

self.defaultIntf().rename("eth0")

for off in ["rx", "tx", "sg"]:

cmd = "/sbin/ethtool --offload eth0 %s off" % off

self.cmd(cmd)

# disable IPv6

self.cmd("sysctl -w net.ipv6.conf.all.disable_ipv6=1")

self.cmd("sysctl -w net.ipv6.conf.default.disable_ipv6=1")

self.cmd("sysctl -w net.ipv6.conf.lo.disable_ipv6=1")

return r

def describe(self):

print "**********"

print self.name

print "default interface: %s\t%s\t%s" %(

self.defaultIntf().name,

self.defaultIntf().IP(),

self.defaultIntf().MAC()

)

print "**********"

class P4Switch(Switch):

"""P4 virtual switch"""

device_id = 0

def __init__(self, name, sw_path = None, json_path = None,

thrift_port = None,

pcap_dump = False,

log_console = False,

verbose = False,

device_id = None,

enable_debugger = False,

**kwargs):

Switch.__init__(self, name, **kwargs)

assert(sw_path)

assert(json_path)

# make sure that the provided sw_path is valid

pathCheck(sw_path)

# make sure that the provided JSON file exists

if not os.path.isfile(json_path):

error("Invalid JSON file.\n")

exit(1)

self.sw_path = sw_path

self.json_path = json_path

self.verbose = verbose

logfile = "/tmp/p4s.{}.log".format(self.name)

self.output = open(logfile, 'w')

self.thrift_port = thrift_port

self.pcap_dump = pcap_dump

self.enable_debugger = enable_debugger

self.log_console = log_console

if device_id is not None:

self.device_id = device_id

P4Switch.device_id = max(P4Switch.device_id, device_id)

else:

self.device_id = P4Switch.device_id

P4Switch.device_id += 1

self.nanomsg = "ipc:///tmp/bm-{}-log.ipc".format(self.device_id)

@classmethod

def setup(cls):

pass

def check_switch_started(self, pid):

"""While the process is running (pid exists), we check if the Thrift

server has been started. If the Thrift server is ready, we assume that

the switch was started successfully. This is only reliable if the Thrift

server is started at the end of the init process"""

while True:

if not os.path.exists(os.path.join("/proc", str(pid))):

return False

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

sock.settimeout(0.5)

result = sock.connect_ex(("localhost", self.thrift_port))

if result == 0:

return True

def start(self, controllers):

"Start up a new P4 switch"

info("Starting P4 switch {}.\n".format(self.name))

args = [self.sw_path]

for port, intf in self.intfs.items():

if not intf.IP():

args.extend(['-i', str(port) + "@" + intf.name])

#wuwzhs edit in 2017/11/10

#args.extend(['-i 3@veth1'])

if self.pcap_dump:

args.append("--pcap")

# args.append("--useFiles")

if self.thrift_port:

args.extend(['--thrift-port', str(self.thrift_port)])

if self.nanomsg:

args.extend(['--nanolog', self.nanomsg])

args.extend(['--device-id', str(self.device_id)])

P4Switch.device_id += 1

args.append(self.json_path)

if self.enable_debugger:

args.append("--debugger")

if self.log_console:

args.append("--log-console")

logfile = "/tmp/p4s.{}.log".format(self.name)

info(' '.join(args) + "\n")

pid = None

with tempfile.NamedTemporaryFile() as f:

# self.cmd(' '.join(args) + ' > /dev/null 2>&1 &')

self.cmd(' '.join(args) + ' >' + logfile + ' 2>&1 & echo $! >> ' + f.name)

pid = int(f.read())

debug("P4 switch {} PID is {}.\n".format(self.name, pid))

if not self.check_switch_started(pid):

error("P4 switch {} did not start correctly.\n".format(self.name))

exit(1)

info("P4 switch {} has been started.\n".format(self.name))

def stop(self):

"Terminate P4 switch."

self.output.flush()

self.cmd('kill %' + self.sw_path)

self.cmd('wait')

self.deleteIntfs()

def attach(self, intf):

"Connect a data port"

assert(0)

def detach(self, intf):

"Disconnect a data port"

assert(0)

[cmd.txt] 0.0001=> allow 100packets/sec , if the each packet size is equal to 1000 bytes, then the obtained throughput can be 100 packets/sec * 1000 (bytes) *8 = 800 kbps

table_add phy_forward forward 1 => 2

table_add phy_forward forward 2 => 1

table_add m_table m_action 00:00:00:00:00:02 => 2

table_set_default m_filter drop

table_add m_filter NoAction 0 =>

meter_set_rates my_meter 2 0.0001:1 0.0005:1

[cmd_add.py]

import os

os.system('sudo /home/vagrant/behavioral-model/targets/simple_switch/simple_switch_CLI --thrift-port=9090 < cmd.txt')

[Execution]

Dr. Chih-Heng Ke (smallko@gmail.com)

Department of Computer Science and Information Engineering,

National Quemoy University, Kinmen, Taiwan.