I hope that you are all doing well,
So I am working on a SDN application using Ryu controller, I want to implement mpls and then trqffic engineering (load balancing) later on. I have started by getting the path using 'shortest path method' from NetworkX library, then using the outport, the traffic should be forwarded. The topology contains 4 switches and 2 hosts ( s1 to s2, s2 to s3 ,s3 to s4 and s1 to s3).
The problem is that when the function (push mpls) is called, the actions within it are not executed! You will notice that I have written at the end of packet in handler actions = packet out ..., it is only how I could ping, if I delete it and insert it with the actions it is not working. I have also tried to return actions from the push mpls function but it is also not working!
If anyone can help me, I will be more than grateful! PS: am talking more about push method cause it's the start
Please find here the code that I am using:
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.topology import event, switches
from ryu.topology.api import get_switch, get_link
import networkx as nx
class SimpleSwitch13(app_manager.RyuApp):
OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
def __init__(self, *args, **kwargs):
super(SimpleSwitch13, self).__init__(*args, **kwargs)
self.mac_to_port = {}
self.net = nx.DiGraph()
self.links = {}
self.switches = {}
self.switch_ports = {}
self.topology_api_app= self
self.label = 16
@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)
def get_path(self, ev):
msg = ev.msg
datapath = msg.datapath
pkt = packet.Packet(msg.data)
eth = pkt.get_protocols(ethernet.ethernet)[0]
dst = eth.dst
src = eth.src
dpid = format(datapath.id, "d").zfill(16)
self.net=nx.DiGraph()
if src not in self.net: #Learn it
self.net.add_node(src) # Add a node to the graph
self.net.add_edge(src,dpid) # Add a link from the node to it's edge switch
self.net.add_edge(dpid,src,port=msg.match['in_port']) # Add link from switch to node and make sure you are identifying the output port.
if dst in self.net:
path=nx.shortest_path(self.net,src,dst) # get shortest path
next=path[path.index(dpid)+1] #get next hop
out_port=self.net[dpid][next]['port'] #get output port
print ('---the path is :----')
print (path)
return out_port, path
return None, None
def push_mpls(self, ev, out_port):
msg = ev.msg
datapath = msg.datapath
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
in_port = msg.match['in_port']
dpid = format(datapath.id, "d").zfill(16)
pkt = packet.Packet(msg.data)
eth = pkt.get_protocols(ethernet.ethernet)[0]
dst = eth.dst
src = eth.src
ethtype = eth.ethertype
match = parser.OFPMatch(in_port=in_port, eth_dst=dst, eth_type=ethtype)
self.label = self.label + 1
self.logger.info("Flow actions: push MPLS=%s, out_port=%s, dst=%s ", self.label, out_port, dst)
actions = []
actions.append(parser.OFPActionPushMpls(ethertype=34887,type_=None, len_=None))
actions.append(parser.OFPActionSetField(mpls_label=self.label))
return
def swap_mpls(self, ev, out_port):
msg = ev.msg
datapath = msg.datapath
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
in_port = msg.match['in_port']
dpid = format(datapath.id, "d").zfill(16)
pkt = packet.Packet(msg.data)
eth = pkt.get_protocols(ethernet.ethernet)[0]
mpls_proto = pkt.get_protocol(mpls.mpls)
# Switch labels
if dpid == 2 :
self.label = self.label + 1
match = parser.OFPMatch(in_port=in_port, eth_dst=dst, eth_type=ethtype, mpls_label=mpls_proto.label)
self.logger.info("Flow actions: switchMPLS=%s, out_port=%s", self.label, out_port)
actions = []
actions.append(parser.OFPActionPopMpls())
actions.append(parser.OFPActionPushMpls())
actions.append (parser.OFPActionSetField(mpls_label=self.label))
elif dpid == 3:
self.label = self.label + 1
match = parser.OFPMatch(in_port=in_port, eth_dst=dst, eth_type=ethtype, mpls_label=mpls_proto.label)
self.logger.info("Flow actions: switchMPLS=%s, out_port=%s", self.label, out_port)
actions = []
actions.append(parser.OFPActionPopMpls())
actions.append(parser.OFPActionPushMpls())
actions.append (parser.OFPActionSetField(mpls_label=self.label))
else:
self.logger.info("Flow actions: Pop MPLS=%s, out_port=%s", self.label, out_port)
actions = []
actions.append(parser.OFPActionPopMpls())
actions.append (parser.OFPActionOutput(out_port))
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
# 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]
if eth.ethertype == ether_types.ETH_TYPE_LLDP:
# ignore lldp packet
return
dst = eth.dst
src = eth.src
ethtype = eth.ethertype
dpid = format(datapath.id, "d").zfill(16)
self.mac_to_port.setdefault(dpid, {})
out_port, path = self.get_path(ev)
if out_port is not None:
out_port =out_port
else:
out_port = ofproto.OFPP_FLOOD
if ethtype == 2048:
self.push_mpls(ev, out_port)
elif ethtype == 34887:
self.swap_mpls(ev, out_port)
actions = [parser.OFPActionOutput(out_port)]
out = parser.OFPPacketOut(datapath=datapath, buffer_id=msg.buffer_id,
in_port=in_port, actions=actions, data=msg.data)
datapath.send_msg(out)
@set_ev_cls(event.EventSwitchEnter)
def get_topology_data(self, ev):
switch_list = get_switch(self.topology_api_app, None)
switches = [switch.dp.id for switch in switch_list]
self.net.add_nodes_from(switches)
links_list = get_link(self.topology_api_app, None)
links = [(link.src.dpid, link.dst.dpid, {'port': link.src.port_no}) for link in links_list]
self.net.add_edges_from(links)
# Store links and switches data in the class variables
self.links = links
self.switches = switches
# Determine input and output ports for each switch
for src_dpid, dst_dpid, link_info in links:
if src_dpid not in self.switch_ports:
self.switch_ports[src_dpid] = {'in_port': [], 'out_port': []}
if dst_dpid not in self.switch_ports:
self.switch_ports[dst_dpid] = {'in_port': [], 'out_port': []}
# Add the input and output ports for each switch
self.switch_ports[src_dpid]['out_port'].append(link_info['port'])
self.switch_ports[dst_dpid]['in_port'].append(link_info['port'])
print('---Links are:------')
print(self.links)
print('--Switch ports:--------')
print(self.switch_ports)
return links, switches
