2019 SDN-on Fifth jobs
1. Browse RYU official website learn to install and controller RYU RYU develop introductory tutorial , tutorials Submit your understanding of the code, including, but not limited to:
1.1 Description Official Tutorial realized what kind of switch function?
A: The official tutorial implements a received packet to all ports of the switch function
What version of the OpenFlow 1.2 controller sets the switches support?
A: The controller sets the switch supports OpenFlow 1.0
1.3 controller set switch how to handle a packet?
answer:
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER) def packet_in_handler(self, ev): msg = ev.msg dp = msg.datapath ofp = dp.ofproto ofp_parser = dp.ofproto_parser actions = [ofp_parser.OFPActionOutput(ofp.OFPP_FLOOD)] out = ofp_parser.OFPPacketOut( datapath=dp, buffer_id=msg.buffer_id,in_port=msg.in_port, actions=actions) dp.send_msg(out)
As shown in the code above, a new method of 'packet_in_handler' has been added to L2Switch class. When Ryu received OpenFlow packet_in message, calling this method. The trick is to "set_ev_cls" decorator. The decorator told Ryu when decorative function should be called. The first parameter indicates the type of event decorator this function should be called; second parameter indicates the state of the switch.
In the first half of packet_in_handler function:
- ev.msg packet_in shows a data structure of the object;
- msg.dp object represents a data path (switch);
- dp.ofproto and dp.ofproto_parser and switches are objects that represent Ryu negotiated OpenFlow protocol;
the second half in packet_in_handler function: - Used in conjunction with class OFPActionOutput packet_out message, the switch sends the packet to specify the port from which. The application uses OFPP_FLOOD flag to indicate that the data packet should be sent on all ports;
- OFPPacketOut message class for constructing packet_out;
- If a class object call message OpenFlow send_msg method Datapath class, Ryu generates line data format and sends it to the switch.
The official tutorial and sample code (SimpleSwitch.py) provided with a switch to the code (SelfLearning.py) self-learning function of the full complement
Original code link
Complete code:
from ryu.base import app_manager
from ryu.controller import ofp_event
from ryu.controller.handler import MAIN_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.ofproto import ofproto_v1_0
from ryu.lib.mac import haddr_to_bin
from ryu.lib.packet import packet
from ryu.lib.packet import ethernet
from ryu.lib.packet import ether_types
from ryu.lib.packet import ipv4
class SimpleSwitch(app_manager.RyuApp):
# TODO define OpenFlow 1.0 version for the switch
# add your code here
OFP_VERSIONS = [ofproto_v1_0.OFP_VERSION]
def __init__(self, *args, **kwargs):
super(SimpleSwitch, self).__init__(*args, **kwargs)
self.mac_to_port = {}
def add_flow(self, datapath, in_port, dst, src, actions):
ofproto = datapath.ofproto
match = datapath.ofproto_parser.OFPMatch(
in_port=in_port,
dl_dst=haddr_to_bin(dst), dl_src=haddr_to_bin(src))
mod = datapath.ofproto_parser.OFPFlowMod(
datapath=datapath, match=match, cookie=0,
command=ofproto.OFPFC_ADD, idle_timeout=0, hard_timeout=0,
priority=ofproto.OFP_DEFAULT_PRIORITY,
flags=ofproto.OFPFF_SEND_FLOW_REM, actions=actions)
# TODO send modified message out
# add your code here
datapath.send_msg(mod)
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
msg = ev.msg
datapath = msg.datapath
ofproto = datapath.ofproto
pkt = packet.Packet(msg.data)
eth = pkt.get_protocol(ethernet.ethernet)
if eth.ethertype == ether_types.ETH_TYPE_LLDP:
# ignore lldp packet
return
if eth.ethertype == ether_types.ETH_TYPE_IPV6:
# ignore ipv6 packet
return
dst = eth.dst
src = eth.src
dpid = datapath.id
self.mac_to_port.setdefault(dpid, {})
self.logger.info("packet in DPID:%s MAC_SRC:%s MAC_DST:%s IN_PORT:%s", dpid, src, dst, msg.in_port)
# learn a mac address to avoid FLOOD next time.
self.mac_to_port[dpid][src] = msg.in_port
if dst in self.mac_to_port[dpid]:
out_port = self.mac_to_port[dpid][dst]
else:
out_port = ofproto.OFPP_FLOOD
# TODO define the action for output
# add your code here
actions = [datapath.ofproto_parser.OFPActionOutput(out_port)]
# install a flow to avoid packet_in next time
if out_port != ofproto.OFPP_FLOOD:
self.logger.info("add flow s:DPID:%s Match:[ MAC_SRC:%s MAC_DST:%s IN_PORT:%s ], Action:[OUT_PUT:%s] ", dpid, src, dst, msg.in_port, out_port)
self.add_flow(datapath, msg.in_port, dst, src, actions)
data = None
if msg.buffer_id == ofproto.OFP_NO_BUFFER:
data = msg.data
# TODO define the OpenFlow Packet Out
# add your code here
out = datapath.ofproto_parser.OFPPacketOut(datapath=datapath, buffer_id=msg.buffer_id, in_port=msg.in_port, actions=actions, data=data)
datapath.send_msg(out)
print ("PACKET_OUT...")
3. Create a simple topology in most mininet, and a controller connected to RYU
Topology Code:
#!/usr/bin/python
#Creating Inernet Topo
from mininet.topo import Topo
class MyTopo(Topo):
def __init__(self):
# initilaize topology
Topo.__init__(self)
# add hosts and switches
h1 = self.addHost('h1')
h2 = self.addHost('h2')
s1 = self.addSwitch('s1')
# add links
self.addLink(h1, s1, 1, 1)
self.addLink(h2, s1, 1, 2)
topos = {'mytopo': (lambda: MyTopo())}
Use command to connect the controller
ryu-manager SelfLearning.py
4. Verify self-learning function switch, submission process and analyze verification results
Delivers flow table
test can ping
Ryu connected controller:
cd ryu
ryu-manager SelfLearning.py
The test again pingall
hair flow following table:
5. Write down your experience experiment
School feel very ignorant, only a step by step tutorial to do according to