build.main

Complexity

Total Complexity

36

Size/Duplication

Total Lines	204
Duplicated Lines	0 %

Test Coverage

Coverage

85.34%

Importance

Changes

0

13 Methods

Rating	Name	Duplication	Size	Complexity
A	Main.list()	0	19	3
A	Main._send_flow_mods_from_request()	0	20	5
A	Main._send_flow_mod()	0	8	1
A	Main.delete()	0	10	1
A	Main._get_all_switches_enabled()	0	4	1
A	Main._send_napp_event()	0	15	4
A	Main.shutdown()	0	3	1
A	Main.setup()	0	9	1
A	Main.execute()	0	2	1
A	Main._install_flows()	0	23	5
C	Main.handle_errors()	0	41	10
A	Main.add()	0	8	1
A	Main._add_flow_mod_sent()	0	5	2

"""kytos/flow_manager NApp installs, lists and deletes switch flows."""
from collections import OrderedDict

from flask import jsonify, request
from pyof.v0x01.asynchronous.error_msg import BadActionCode as BadActionCode01
from pyof.v0x01.common.phy_port import PortConfig as PortConfig01
from pyof.v0x04.asynchronous.error_msg import BadActionCode as BadActionCode04
from pyof.v0x04.common.port import PortConfig as PortConfig04

from kytos.core import KytosEvent, KytosNApp, log, rest
from kytos.core.helpers import listen_to
from napps.kytos.of_core.flow import FlowFactory

from .exceptions import InvalidCommandError
from .settings import FLOWS_DICT_MAX_SIZE


class Main(KytosNApp):
    """Main class to be used by Kytos controller."""

    def setup(self):
        """Replace the 'init' method for the KytosApp subclass.

        The setup method is automatically called by the run method.
        Users shouldn't call this method directly.
        """
        log.debug("flow-manager starting")
        self._flow_mods_sent = OrderedDict()
        self._flow_mods_sent_max_size = FLOWS_DICT_MAX_SIZE

    def execute(self):
        """Run once on NApp 'start' or in a loop.

        The execute method is called by the run method of KytosNApp class.
        Users shouldn't call this method directly.
        """

    def shutdown(self):
        """Shutdown routine of the NApp."""
        log.debug("flow-manager stopping")

    @rest('v2/flows')
    @rest('v2/flows/<dpid>')
    def list(self, dpid=None):
        """Retrieve all flows from a switch identified by dpid.

        If no dpid is specified, return all flows from all switches.
        """
        if dpid is None:
            switches = self.controller.switches.values()
        else:
            switches = [self.controller.get_switch_by_dpid(dpid)]

        switch_flows = {}

        for switch in switches:
            flows_dict = [flow.as_dict() for flow in switch.flows]
            switch_flows[switch.dpid] = {'flows': flows_dict}

        return jsonify(switch_flows)

    @rest('v2/flows', methods=['POST'])
    @rest('v2/flows/<dpid>', methods=['POST'])
    def add(self, dpid=None):
        """Install new flows in the switch identified by dpid.

        If no dpid is specified, install flows in all switches.
        """
        return self._send_flow_mods_from_request(dpid, "add")

    @rest('v2/delete', methods=['POST'])
    @rest('v2/delete/<dpid>', methods=['POST'])
    @rest('v2/flows', methods=['DELETE'])
    @rest('v2/flows/<dpid>', methods=['DELETE'])
    def delete(self, dpid=None):
        """Delete existing flows in the switch identified by dpid.

        If no dpid is specified, delete flows from all switches.
        """
        return self._send_flow_mods_from_request(dpid, "delete")

    def _get_all_switches_enabled(self):
        """Get a list of all switches enabled."""
        switches = self.controller.switches.values()
        return [switch for switch in switches if switch.is_enabled()]

    def _send_flow_mods_from_request(self, dpid, command):
        """Install FlowsMods from request."""
        flows_dict = request.get_json()

        if flows_dict is None:
            return jsonify({"response": 'flows dict is none.'}), 404

        if dpid:
            switch = self.controller.get_switch_by_dpid(dpid)
            if not switch:
                return jsonify({"response": 'dpid not found.'}), 404
            elif switch.is_enabled() is False:
                return jsonify({"response": 'switch is disabled.'}), 404
            else:
                self._install_flows(command, flows_dict, [switch])
        else:
            self._install_flows(command, flows_dict,
                                self._get_all_switches_enabled())

        return jsonify({"response": "FlowMod Messages Sent"})

    def _install_flows(self, command, flows_dict, switches=[]):
        """Execute all procedures to install flows in the switches.

        Args:
            command: Flow command to be installed
            flows_dict: Dictionary with flows to be installed in the switches.
            switches: A list of switches
        """
        for switch in switches:
            serializer = FlowFactory.get_class(switch)
            flows = flows_dict.get('flows', [])
            for flow_dict in flows:
                flow = serializer.from_dict(flow_dict, switch)
                if command == "delete":
                    flow_mod = flow.as_of_delete_flow_mod()
                elif command == "add":
                    flow_mod = flow.as_of_add_flow_mod()
                else:
                    raise InvalidCommandError
                self._send_flow_mod(flow.switch, flow_mod)
                self._add_flow_mod_sent(flow_mod.header.xid, flow)

                self._send_napp_event(switch, flow, command)

    def _add_flow_mod_sent(self, xid, flow):
        """Add the flow mod to the list of flow mods sent."""
        if len(self._flow_mods_sent) >= self._flow_mods_sent_max_size:
            self._flow_mods_sent.popitem(last=False)
        self._flow_mods_sent[xid] = flow

    def _send_flow_mod(self, switch, flow_mod):
        event_name = 'kytos/flow_manager.messages.out.ofpt_flow_mod'

        content = {'destination': switch.connection,
                   'message': flow_mod}

        event = KytosEvent(name=event_name, content=content)
        self.controller.buffers.msg_out.put(event)

    def _send_napp_event(self, switch, flow, command, **kwargs):
        """Send an Event to other apps informing about a FlowMod."""
        if command == 'add':
            name = 'kytos/flow_manager.flow.added'
        elif command == 'delete':
            name = 'kytos/flow_manager.flow.removed'
        elif command == 'error':
            name = 'kytos/flow_manager.flow.error'
        else:
            raise InvalidCommandError
        content = {'datapath': switch,
                   'flow': flow}
        content.update(kwargs)
        event_app = KytosEvent(name, content)
        self.controller.buffers.app.put(event_app)

    @listen_to('.*.of_core.*.ofpt_error')
    def handle_errors(self, event):
        """Receive OpenFlow error and send a event.

        The event is sent only if the error is related to a request made
        by flow_manager.
        """
        message = event.content["message"]
        connection = event.source
        switch = connection.switch

        error_data = message.data.pack()
        # Get the packet responsible for the error
        error_packet = connection.protocol.unpack(error_data)

        if (message.code == BadActionCode01.OFPBAC_BAD_OUT_PORT or
           message.code == BadActionCode04.OFPBAC_BAD_OUT_PORT):

            for action in error_packet.actions:
                try:
                    iface = switch.get_interface_by_port_no(action.port.value)
                except AttributeError:
                    iface = switch.get_interface_by_port_no(action.port)

                # Check interface to drop packets forwarded to it
                if iface:
                    if connection.protocol.version == 0x01:
                        iface.config = PortConfig01.OFPPC_NO_FWD
                    elif connection.protocol.version == 0x04:
                        iface.config = PortConfig04.OFPPC_NO_FWD

        xid = message.header.xid.value
        error_type = message.error_type
        error_code = message.code
        try:
            flow = self._flow_mods_sent[xid]
        except KeyError:
            pass
        else:
            self._send_napp_event(flow.switch, flow, 'error',
                                  error_type=error_type, error_code=error_code)