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l2.py
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l2.py
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__author__ = 'Ehsan'
""" ryu.base.app_manager:
The central management of Ryu applications.
- Load Ryu applications
- Provide contexts to Ryu applications
- Route messages among Ryu applications
"""
from ryu.base import app_manager
"""ryu.controller.ofp_event:
OpenFlow event definitions.
"""
from ryu.controller import ofp_event
# Version negotiated and sent features-request message
from ryu.controller.handler import CONFIG_DISPATCHER
from ryu.ofproto import ofproto_v1_3
# Switch-features message received and sent set-config message
from ryu.controller.handler import MAIN_DISPATCHER
from ryu.controller.handler import set_ev_cls
"""ryu.lib.packet:
Ryu packet library. Decoder/Encoder implementations of popular protocols like TCP/IP.
"""
from ryu.lib.packet import packet
from ryu.lib.packet import ethernet
from ryu.lib.packet import ether_types
from ryu.lib import dpid as dpid_lib
"""
Usage Example:
1. Run this application:
$ sudo ryu-manager --verbose --observe-links ~/code/RyuApp/l2.py
2. Join switches (use your favorite method):
$ sudo mn --controller=remote --topo linear,2
"""
"""
In order to implement as a Ryu application, ryu.base.app_manager.RyuApp is inherited. Also, to use
OpenFlow 1.3, the OpenFlow 1.3 version is specified for OFP_VERSIONS.
The http://osrg.github.io/ryu-book/en/html/switching_hub.html explain similar features pretty good.
"""
class L2Switch(app_manager.RyuApp):
OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
def __init__(self, *args, **kwargs):
super(L2Switch, self).__init__(*args, **kwargs)
self.mac_to_port = {}
@set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
def switch_features_handler(self, ev):
self.logger.info("[Ehsan] Received EventOFPSwitchFeatures")
msg = ev.msg
self.logger.info('OFPSwitchFeatures received: '
'\n\tdatapath_id=0x%016x n_buffers=%d '
'\n\tn_tables=%d auxiliary_id=%d '
'\n\tcapabilities=0x%08x',
msg.datapath_id, msg.n_buffers, msg.n_tables,
msg.auxiliary_id, msg.capabilities)
datapath = ev.msg.datapath
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
# install table-miss flow entry
#
# We specify NO BUFFER to max_len of the output action due to
# OVS bug. At this moment, if we specify a lesser number, e.g.,
# 128, OVS will send Packet-In with invalid buffer_id and
# truncated packet data. In that case, we cannot output packets
# correctly. The bug has been fixed in OVS v2.1.0.
match = parser.OFPMatch()
actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
ofproto.OFPCML_NO_BUFFER)]
self.add_flow(datapath, 0, match, actions)
def add_flow(self, datapath, priority, match, actions, buffer_id=None):
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,
actions)]
if buffer_id:
mod = parser.OFPFlowMod(datapath=datapath, buffer_id=buffer_id,
priority=priority, match=match,
instructions=inst)
else:
mod = parser.OFPFlowMod(datapath=datapath, priority=priority,
match=match, instructions=inst)
datapath.send_msg(mod)
"""
This is called when Ryu receives an OpenFlow packet_in message. The trick is set_ev_cls decorator. This decorator
tells Ryu when the decorated function should be called.
Arguments of the decorator:
1. The first argument of the decorator indicates an event that makes function called. As you expect easily, every time
Ryu gets a packet_in message, this function is called.
2. The second argument indicates the state of the switch. Probably, you want to ignore packet_in messages before the
negotiation between Ryu and the switch finishes. Using MAIN_DISPATCHER as the second argument means this function
is called only after the negotiation completes.
"""
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
#self.logger.info("[Ehsan] Received EventOFPPacketIn")
# If you hit this you might want to increase
# the "miss_send_length" of your switch
if ev.msg.msg_len < ev.msg.total_len:
self.logger.debug("packet truncated: only %s of %s bytes",
ev.msg.msg_len, ev.msg.total_len)
msg = ev.msg
datapath = msg.datapath
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
in_port = msg.match['in_port']
pkt = packet.Packet(msg.data)
eth = pkt.get_protocols(ethernet.ethernet)[0]
dst = eth.dst
src = eth.src
dpid = datapath.id
self.mac_to_port.setdefault(dpid, {})
self.logger.info("\tpacket in %s %s %s %s", dpid, src, dst, in_port)
# learn a mac address to avoid FLOOD next time.
self.mac_to_port[dpid][src] = in_port
if dst in self.mac_to_port[dpid]:
out_port = self.mac_to_port[dpid][dst]
else:
out_port = ofproto.OFPP_FLOOD
actions = [parser.OFPActionOutput(out_port)]
# install a flow to avoid packet_in next time
if out_port != ofproto.OFPP_FLOOD:
match = parser.OFPMatch(in_port=in_port, eth_dst=dst)
# verify if we have a valid buffer_id, if yes avoid to send both
# flow_mod & packet_out
if msg.buffer_id != ofproto.OFP_NO_BUFFER:
self.add_flow(datapath, 1, match, actions, msg.buffer_id)
return
else:
self.add_flow(datapath, 1, match, actions)
data = None
if msg.buffer_id == ofproto.OFP_NO_BUFFER:
data = msg.data
out = parser.OFPPacketOut(datapath=datapath, buffer_id=msg.buffer_id,
in_port=in_port, actions=actions, data=data)
datapath.send_msg(out)
"""
EventOFPPortStatus: An event class for switch port status notification.
The bellow handles the event.
"""
@set_ev_cls(ofp_event.EventOFPPortStatus, MAIN_DISPATCHER)
def _port_status_handler(self, ev):
#self.logger.info("[Ehsan] Received EventOFPPortStatus")
""" Port status message
The switch notifies controller of change of ports.
Attribute | Description
--------------------------------
reason | One of the following values.
| OFPPR_ADD
| OFPPR_DELETE
| OFPPR_MODIFY
--------------------------------
desc | instance of OFPPort
"""
msg = ev.msg
dp = msg.datapath
reason = msg.reason
port_no = msg.desc.port_no
ofproto = msg.datapath.ofproto
if reason == ofproto.OFPPR_ADD:
self.logger.info("\tport added %s", port_no)
elif reason == ofproto.OFPPR_DELETE:
self.logger.info("\tport deleted %s", port_no)
elif reason == ofproto.OFPPR_MODIFY:
self.logger.info("\tport modified %s", port_no)
dp_str = dpid_lib.dpid_to_str(dp.id)
self.logger.info("\t[Ehsan] Sending send_port_desc_stats_request to datapath id : " + dp_str)
self.send_port_desc_stats_request(dp)
else:
self.logger.info("\tIlleagal port state %s %s", port_no, reason)
def send_port_stats_request(self, datapath):
ofp = datapath.ofproto
ofp_parser = datapath.ofproto_parser
"""
class ryu.ofproto.ofproto_v1_3_parser.OFPPortStatsRequest(datapath, flags=0, port_no=4294967295, type_=None)
Port statistics request message
The controller uses this message to query information about ports statistics.
Attribute | Description
--------------------------
flags | Zero or OFPMPF_REQ_MORE
port_no | Port number to read (OFPP_ANY to all ports)
"""
req = ofp_parser.OFPPortStatsRequest(datapath, 0, ofp.OFPP_ANY)
datapath.send_msg(req)
"""
Creates an event handler that receives the PortStatsReply message.
The bellow handles the event.
"""
@set_ev_cls(ofp_event.EventOFPPortStatsReply, MAIN_DISPATCHER)
def port_stats_reply_handler(self, ev):
#self.logger.info("[Ehsan] Received EventOFPPortStatsReply")
#self.logger.info('PortStats: \n')
""" Port statistics reply message
The switch responds with this message to a port statistics request.
Attribute | Description
-----------------------
body | List of OFPPortStats instance
"""
for stat in ev.msg.body:
self.logger.info("\tport_no=%d "
"rx_packets=%d tx_packets=%d "
"\n \trx_bytes=%d tx_bytes=%d "
"rx_dropped=%d tx_dropped=%d "
"rx_errors=%d tx_errors=%d "
"\n \trx_frame_err=%d rx_over_err=%d rx_crc_err=%d "
"\n \tcollisions=%d duration_sec=%d duration_nsec=%d" %
(stat.port_no,
stat.rx_packets, stat.tx_packets,
stat.rx_bytes, stat.tx_bytes,
stat.rx_dropped, stat.tx_dropped,
stat.rx_errors, stat.tx_errors,
stat.rx_frame_err, stat.rx_over_err,
stat.rx_crc_err, stat.collisions,
stat.duration_sec, stat.duration_nsec))
def send_port_desc_stats_request(self, datapath):
ofp_parser = datapath.ofproto_parser
req = ofp_parser.OFPPortDescStatsRequest(datapath, 0)
datapath.send_msg(req)
"""
EventOFPPortDescStatsReply: an event where it is fired when Port description reply message
The bellow handles the event.
"""
@set_ev_cls(ofp_event.EventOFPPortDescStatsReply, MAIN_DISPATCHER)
def port_desc_stats_reply_handler(self, ev):
#self.logger.info('OFPPortDescStatsReply received: \n')
"""
Port description reply message
The switch responds with this message to a port description request.
Attribute | Description
------------|---------------
body | List of OFPPortDescStats instance
"""
for p in ev.msg.body:
self.logger.info("\t port_no=%d hw_addr=%s name=%s config=0x%08x "
"\n \t state=0x%08x curr=0x%08x advertised=0x%08x "
"\n \t supported=0x%08x peer=0x%08x curr_speed=%d "
"max_speed=%d" %
(p.port_no, p.hw_addr,
p.name, p.config,
p.state, p.curr, p.advertised,
p.supported, p.peer, p.curr_speed,
p.max_speed))