sdn控制器拓扑发现(三) --lldp

   


 def _port_added(self, port):
        lldp_data = LLDPPacket.lldp_packet(
            port.dpid, port.port_no, port.hw_addr, self.DEFAULT_TTL)
        self.ports.add_port(port, lldp_data)
        # LOG.debug('_port_added dpid=%s, port_no=%s, live=%s',
        #           port.dpid, port.port_no, port.is_live())

    @set_ev_cls(ofp_event.EventOFPPortStatus, MAIN_DISPATCHER)
    def port_status_handler(self, ev):
        msg = ev.msg
        reason = msg.reason
        dp = msg.datapath
        ofpport = msg.desc

        if reason == dp.ofproto.OFPPR_ADD:
            # LOG.debug('A port was added.' +
            #           '(datapath id = %s, port number = %s)',
            #           dp.id, ofpport.port_no)
            self.port_state[dp.id].add(ofpport.port_no, ofpport)
            self.send_event_to_observers(
                event.EventPortAdd(Port(dp.id, dp.ofproto, ofpport)))

            if not self.link_discovery:
                return

            port = self._get_port(dp.id, ofpport.port_no)
            if port and not port.is_reserved():
                self._port_added(port)
                self.lldp_event.set()

 def state_change_handler(self, ev):
        dp = ev.datapath
        assert dp is not None
        LOG.debug(dp)

            # Do not add ports while dp has multiple connections to controller.
            if not dp_multiple_conns:
                for port in switch.ports:
                    if not port.is_reserved():
                        self._port_added(port)

    @staticmethod
    def lldp_packet(dpid, port_no, dl_addr, ttl):
        pkt = packet.Packet()

        dst = lldp.LLDP_MAC_NEAREST_BRIDGE
        src = dl_addr
        ethertype = ETH_TYPE_LLDP
        eth_pkt = ethernet.ethernet(dst, src, ethertype)
        pkt.add_protocol(eth_pkt)

        tlv_chassis_id = lldp.ChassisID(
            subtype=lldp.ChassisID.SUB_LOCALLY_ASSIGNED,
            chassis_id=(LLDPPacket.CHASSIS_ID_FMT %
                        dpid_to_str(dpid)).encode('ascii'))

        tlv_port_id = lldp.PortID(subtype=lldp.PortID.SUB_PORT_COMPONENT,
                                  port_id=struct.pack(
                                      LLDPPacket.PORT_ID_STR,
                                      port_no))

        tlv_ttl = lldp.TTL(ttl=ttl)
        tlv_end = lldp.End()

        tlvs = (tlv_chassis_id, tlv_port_id, tlv_ttl, tlv_end)
        lldp_pkt = lldp.lldp(tlvs)
        pkt.add_protocol(lldp_pkt)

        pkt.serialize()
        return pkt.data

    @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)
        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)