<public> Ryu: SLDP re-implementation - ryu

Question

Re-implementation of Secured Lightweight Link Discovery Protocol
Kindly help debug the code below.
The helps provided in the private post have been noted. But i still have new challenges.
Thanks
#Re-implementation of SLDP
from ryu.base import app_manager
from ryu.controller import ofp_event
from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.ofproto import ofproto_v1_3
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
from ryu.topology import switches
from ryu.lib.packet import lldp
import logging
import time
from ryu.lib import hub
LOG = logging.getLogger(__name__)
class SimpleSwitch13(app_manager.RyuApp):
OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
_CONTEXTS = {
'switches': switches.Switches,
}
def __init__(self, *args, **kwargs):
super(SimpleSwitch13, self).__init__(*args, **kwargs)
self.mac_to_port = {}
self.is_active = True
#set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
def switch_features_handler(self, ev):
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)
#set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
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]
if eth.ethertype == ether_types.ETH_TYPE_LLDP:
# ignore lldp packet
#print("lldp packet")
return
#dst = eth.dst
dst = 'ff:ff:ff:ff:ff:ff'
src = eth.src
#print("not lldp packet")
dpid = datapath.id
self.mac_to_port.setdefault(dpid, {})
self.logger.info("packet 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
# eth_type=0xabcd, eth_dst='ff:ff:ff:ff:ff:ff',
if out_port != ofproto.OFPP_FLOOD:
match = parser.OFPMatch(in_port=in_port, eth_dst=dst, eth_src=src)
self.add_flow(datapath, 1, match, actions)
self.logger.info("not Flood")
data = None
if msg.buffer_id == ofproto.OFP_NO_BUFFER:
data = msg.data
match = parser.OFPMatch(in_port=in_port, eth_type=0xabcd, eth_dst='ff:ff:ff:ff:ff:ff', eth_src=src)
self.add_flow(datapath, 1, match, actions)
self.logger.info("Flood")
out = parser.OFPPacketOut(datapath=datapath, buffer_id=msg.buffer_id,
in_port=in_port, actions=actions, data=data)
datapath.send_msg(out)
#set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
msg = ev.msg
datapath = msg.datapath
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
in_port = msg.match['in_port']
#set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def lldp_packet_in_handler(self, ev):
if not self.link_discovery:
return
msg = ev.msg
try:
src_dpid, src_port_no = LLDPPacket.lldp_parse(msg.data)
except LLDPPacket.LLDPUnknownFormat:
# This handler can receive all the packets which can be
# not-LLDP packet. Ignore it silently
return
dst_dpid = msg.datapath.id
if msg.datapath.ofproto.OFP_VERSION == ofproto_v1_0.OFP_VERSION:
dst_port_no = msg.in_port
elif msg.datapath.ofproto.OFP_VERSION >= ofproto_v1_2.OFP_VERSION:
dst_port_no = msg.match['in_port']
else:
LOG.error('cannot accept LLDP. unsupported version. %x',
msg.datapath.ofproto.OFP_VERSION)
src = self._get_port(src_dpid, src_port_no)
print("im in here")
if not src or src.dpid == dst_dpid:
return
try:
self.ports.lldp_received(src)
except KeyError:
# There are races between EventOFPPacketIn and
# EventDPPortAdd. So packet-in event can happend before
# port add event. In that case key error can happend.
# LOG.debug('lldp_received error', exc_info=True)
pass
dst = self._get_port(dst_dpid, dst_port_no)
if not dst:
return
old_peer = self.links.get_peer(src)
# LOG.debug("Packet-In")
# LOG.debug(" src=%s", src)
# LOG.debug(" dst=%s", dst)
# LOG.debug(" old_peer=%s", old_peer)
if old_peer and old_peer != dst:
old_link = Link(src, old_peer)
del self.links[old_link]
self.send_event_to_observers(event.EventLinkDelete(old_link))
link = Link(src, dst)
if link not in self.links:
self.send_event_to_observers(event.EventLinkAdd(link))
# remove hosts if it's not attached to edge port
host_to_del = []
for host in self.hosts.values():
if not self._is_edge_port(host.port):
host_to_del.append(host.mac)
for host_mac in host_to_del:
del self.hosts[host_mac]
if not self.links.update_link(src, dst):
# reverse link is not detected yet.
# So schedule the check early because it's very likely it's up
self.ports.move_front(dst)
self.lldp_event.set()
if self.explicit_drop:
self._drop_packet(msg)
I got the protocol setup nicely. The host-switch linking was successful
I have imported all the needed modules, yet it couldnt find link_discovery
The helps provided in the private post have been noted. But i still have new challenges.
Thanks