build.managers.flow_builder

Complexity

Total Complexity

32

Size/Duplication

Total Lines	295
Duplicated Lines	0 %

Test Coverage

Coverage

98.43%

Importance

Changes

0

5 Methods

Rating	Name	Duplication	Size	Complexity
C	FlowBuilder._build_int_source_flows()	0	97	11
C	FlowBuilder._build_int_sink_flows()	0	105	10
A	FlowBuilder.__init__()	0	3	1
A	FlowBuilder.build_int_flows()	0	23	3
B	FlowBuilder._build_int_hop_flows()	0	47	7

"""flow_builder module responsible for building and mapping flows."""

import copy
from collections import defaultdict
import itertools

from typing import Literal

from napps.kytos.telemetry_int import utils
from napps.kytos.telemetry_int import settings


class FlowBuilder:
    """FlowBuilder."""

    def __init__(self):
        """Constructor of FlowBuilder."""
        self.table_group = {"evpl": 2, "epl": 3}

    def build_int_flows(
        self,
        evcs: dict[str, dict],
        stored_flows: dict[int, list[dict]],
    ) -> dict[int, list[dict]]:
        """build INT flows.

        It'll map and create all INT flows needed, for now since each EVC
        is bidirectional, it'll provision bidirectionally too. In the future,
        if mef_eline supports unidirectional EVC, it'll follow suit accordingly.
        """
        flows_per_cookie: dict[int, list[dict]] = defaultdict(list)
        for evc_id, evc in evcs.items():
            for flow in itertools.chain(
                self._build_int_source_flows("uni_a", evc, stored_flows),
                self._build_int_source_flows("uni_z", evc, stored_flows),
                self._build_int_hop_flows(evc, stored_flows),
                self._build_int_sink_flows("uni_z", evc, stored_flows),
                self._build_int_sink_flows("uni_a", evc, stored_flows),
            ):
                cookie = utils.get_cookie(evc_id, settings.MEF_COOKIE_PREFIX)
                flows_per_cookie[cookie].append(flow)
        return flows_per_cookie

    def _build_int_source_flows(
        self,
        uni_src_key: Literal["uni_a", "uni_z"],
        evc: dict,
        stored_flows: dict[int, list[dict]],
    ) -> list[dict]:
        """Build INT source flows.

        At the INT source, one flow becomes 3: one for UDP on table 0,
        one for TCP on table 0, and one on table X (2 for evpl and 3 for epl by default)
        On table 0, we use just new instructions: push_int and goto_table
        On table X, we add add_int_metadata before the original actions
        INT flows will have higher priority.
        """
        new_flows = []
        new_int_flow_tbl_0_tcp = {}
        src_uni = evc[uni_src_key]

        # Get the original flows
        dpid = src_uni["switch"]
        for flow in stored_flows[
            utils.get_cookie(evc["id"], settings.MEF_COOKIE_PREFIX)
        ]:
            if (
                flow["switch"] == dpid
                and flow["flow"]["match"]["in_port"] == src_uni["port_number"]
            ):
                new_int_flow_tbl_0_tcp = copy.deepcopy(flow)
                break

        if not new_int_flow_tbl_0_tcp:
            return []

        utils.set_instructions_from_actions(new_int_flow_tbl_0_tcp)
        utils.set_new_cookie(new_int_flow_tbl_0_tcp)
        utils.set_owner(new_int_flow_tbl_0_tcp)

        # Deepcopy to use for table X (2 or 3 by default for EVPL or EPL respectively)
        new_int_flow_tbl_x = copy.deepcopy(new_int_flow_tbl_0_tcp)

        # Prepare TCP Flow for Table 0
        new_int_flow_tbl_0_tcp["flow"]["match"]["dl_type"] = settings.IPv4
        new_int_flow_tbl_0_tcp["flow"]["match"]["nw_proto"] = settings.TCP
        utils.set_priority(new_int_flow_tbl_0_tcp)

        # The flow_manager has two outputs: instructions and actions.
        table_group = self.table_group
        new_table_id = table_group[new_int_flow_tbl_x["flow"]["table_group"]]
        instructions = [
            {
                "instruction_type": "apply_actions",
                "actions": [{"action_type": "push_int"}],
            },
            {"instruction_type": "goto_table", "table_id": new_table_id},
        ]
        new_int_flow_tbl_0_tcp["flow"]["instructions"] = instructions

        # Prepare UDP Flow for Table 0. Everything the same as TCP except the nw_proto
        new_int_flow_tbl_0_udp = copy.deepcopy(new_int_flow_tbl_0_tcp)
        new_int_flow_tbl_0_udp["flow"]["match"]["nw_proto"] = settings.UDP

        # Prepare Flows for Table X - No TCP or UDP specifics
        new_int_flow_tbl_x["flow"]["table_id"] = new_table_id

        # if intra-switch EVC, then output port should be the dst UNI's source port
        if utils.is_intra_switch_evc(evc):
            dst_uni = evc["uni_z" if uni_src_key == "uni_a" else "uni_a"]
            proxy_port = dst_uni["proxy_port"]
            for instruction in new_int_flow_tbl_x["flow"]["instructions"]:
                if instruction["instruction_type"] == "apply_actions":
                    for action in instruction["actions"]:
                        if action["action_type"] == "output":
                            # Since this is the INT Source, we use source
                            # to avoid worrying about single or multi
                            # home physical loops.
                            # The choice for destination is at the INT Sink.
                            action["port"] = proxy_port.source.port_number

                    # remove set_vlan action if it exists, this is for
                    # avoding a redundant set_vlan since it'll be set in the egress sink
                    instruction["actions"] = utils.modify_actions(
                        instruction["actions"], ["set_vlan"], remove=True
                    )

        instructions = utils.add_to_apply_actions(
            new_int_flow_tbl_x["flow"]["instructions"],
            new_instruction={"action_type": "add_int_metadata"},
            position=0,
        )

        new_int_flow_tbl_x["flow"]["instructions"] = instructions

        new_flows.append(new_int_flow_tbl_0_tcp)
        new_flows.append(new_int_flow_tbl_0_udp)
        new_flows.append(new_int_flow_tbl_x)

        return new_flows

    def _build_int_hop_flows(
        self,
        evc: dict,
        stored_flows: dict[int, list[dict]],
    ) -> list[dict]:
        """Build INT hop flows.

        At the INT hops, one flow adds two more: one for UDP on table 0,
        one for TCP on table 0. On table 0, we add 'add_int_metadata'
        before other actions.
        """

        new_flows = []
        excluded_dpids = set([evc["uni_a"]["switch"], evc["uni_z"]["switch"]])

        for flow in stored_flows[
            utils.get_cookie(evc["id"], settings.MEF_COOKIE_PREFIX)
        ]:
            if flow["switch"] in excluded_dpids:
                continue
            if "match" not in flow["flow"] or "in_port" not in flow["flow"]["match"]:
                continue

            new_int_flow_tbl_0_tcp = copy.deepcopy(flow)
            utils.set_instructions_from_actions(new_int_flow_tbl_0_tcp)
            utils.set_new_cookie(new_int_flow_tbl_0_tcp)
            utils.set_owner(new_int_flow_tbl_0_tcp)

            # Prepare TCP Flow
            new_int_flow_tbl_0_tcp["flow"]["match"]["dl_type"] = settings.IPv4
            new_int_flow_tbl_0_tcp["flow"]["match"]["nw_proto"] = settings.TCP
            utils.set_priority(new_int_flow_tbl_0_tcp)

            for instruction in new_int_flow_tbl_0_tcp["flow"]["instructions"]:
                if instruction["instruction_type"] == "apply_actions":
                    instruction["actions"].insert(
                        0, {"action_type": "add_int_metadata"}
                    )

            # Prepare UDP Flow
            new_int_flow_tbl_0_udp = copy.deepcopy(new_int_flow_tbl_0_tcp)
            new_int_flow_tbl_0_udp["flow"]["match"]["nw_proto"] = settings.UDP

            new_flows.append(new_int_flow_tbl_0_tcp)
            new_flows.append(new_int_flow_tbl_0_udp)

        return new_flows

    def _build_int_sink_flows(
        self,
        uni_dst_key: Literal["uni_a", "uni_z"],
        evc: dict,
        stored_flows: dict[int, list[dict]],
    ) -> list[dict]:
        """
        Build INT sink flows.

        At the INT sink, one flow becomes many:
        1. Before the proxy, we do add_int_metadata as an INT hop.
        We need to keep the set_queue
        2. After the proxy, we do send_report and pop_int and output
        We only use table 0 for #1.
        We use table X (2 or 3) for #2. for pop_int and output
        """
        new_flows = []
        dst_uni = evc[uni_dst_key]
        proxy_port = dst_uni["proxy_port"]
        dpid = dst_uni["switch"]

        for flow in stored_flows[
            utils.get_cookie(evc["id"], settings.MEF_COOKIE_PREFIX)
        ]:
            # Only consider this sink's dpid flows
            if flow["switch"] != dpid:
                continue
            # Only consider flows coming from NNI interfaces
            if flow["flow"]["match"]["in_port"] == dst_uni["port_number"]:
                continue

            new_int_flow_tbl_0_tcp = copy.deepcopy(flow)

            if not new_int_flow_tbl_0_tcp:
                continue

            utils.set_new_cookie(new_int_flow_tbl_0_tcp)
            utils.set_owner(new_int_flow_tbl_0_tcp)
            utils.set_instructions_from_actions(new_int_flow_tbl_0_tcp)

            # Save for pos-proxy flows
            new_int_flow_tbl_0_pos = copy.deepcopy(new_int_flow_tbl_0_tcp)
            new_int_flow_tbl_x_pos = copy.deepcopy(new_int_flow_tbl_0_tcp)

            # Prepare TCP Flow for Table 0 PRE proxy
            if not utils.is_intra_switch_evc(evc):
                new_int_flow_tbl_0_tcp["flow"]["match"]["dl_type"] = settings.IPv4
                new_int_flow_tbl_0_tcp["flow"]["match"]["nw_proto"] = settings.TCP
                utils.set_priority(new_int_flow_tbl_0_tcp)

                # Add telemetry, keep set_queue, output to the proxy port.
                output_port_no = proxy_port.source.port_number
                for instruction in new_int_flow_tbl_0_tcp["flow"]["instructions"]:
                    if instruction["instruction_type"] == "apply_actions":
                        # Keep set_queue
                        actions = utils.modify_actions(
                            instruction["actions"],
                            ["pop_vlan", "push_vlan", "set_vlan", "output"],
                            remove=True,
                        )
                        actions.insert(0, {"action_type": "add_int_metadata"})
                        actions.append(
                            {"action_type": "output", "port": output_port_no}
                        )
                        instruction["actions"] = actions

                # Prepare UDP Flow for Table 0
                new_int_flow_tbl_0_udp = copy.deepcopy(new_int_flow_tbl_0_tcp)
                new_int_flow_tbl_0_udp["flow"]["match"]["nw_proto"] = settings.UDP

                new_flows.append(copy.deepcopy(new_int_flow_tbl_0_tcp))
                new_flows.append(copy.deepcopy(new_int_flow_tbl_0_udp))

            # Prepare Flows for Table 0 AFTER proxy. No difference between TCP or UDP
            in_port_no = proxy_port.destination.port_number

            new_int_flow_tbl_0_pos["flow"]["match"]["in_port"] = in_port_no
            utils.set_priority(new_int_flow_tbl_0_tcp)

            table_group = self.table_group
            new_table_id = table_group[new_int_flow_tbl_x_pos["flow"]["table_group"]]
            instructions = [
                {
                    "instruction_type": "apply_actions",
                    "actions": [{"action_type": "send_report"}],
                },
                {
                    "instruction_type": "goto_table",
                    "table_id": new_table_id,
                },
            ]
            new_int_flow_tbl_0_pos["flow"]["instructions"] = instructions

            # Prepare Flows for Table X POS proxy
            new_int_flow_tbl_x_pos["flow"]["match"]["in_port"] = in_port_no
            new_int_flow_tbl_x_pos["flow"]["table_id"] = new_table_id

            for instruction in new_int_flow_tbl_x_pos["flow"]["instructions"]:
                if instruction["instruction_type"] == "apply_actions":
                    instruction["actions"].insert(0, {"action_type": "pop_int"})

            new_flows.append(copy.deepcopy(new_int_flow_tbl_0_pos))
            new_flows.append(copy.deepcopy(new_int_flow_tbl_x_pos))

        return new_flows