build.main.Main.do_match() - Code Metrics - Inspection of "Support instruction type goto_table" - kytos-ng/sdntrace_cp - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Pull Request — master (#108)

unknown

created 2023-10-11 20:53 UTC

build.main.Main.do_match() C

↳ Parent: build.main

Complexity

Conditions

Size

Total Lines	28
Code Lines	23

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	21
CRAP Score	11.0795

Importance

Changes

Metric	Value
eloc	23
dl	0
loc	28
ccs	21
cts	23
cp	0.913
rs	5.4
c	0
b	0
f	0
cc	11
nop	4
crap	11.0795

How to fix Complexity

"""Main module of amlight/sdntrace_cp Kytos Network Application.

Run tracepaths on OpenFlow in the Control Plane
"""

import pathlib
from datetime import datetime

import tenacity
from kytos.core import KytosNApp, log, rest
from kytos.core.helpers import load_spec, validate_openapi
from kytos.core.rest_api import (HTTPException, JSONResponse, Request,
                                 get_json_or_400)
from napps.amlight.sdntrace_cp.utils import (convert_entries,
                                             convert_list_entries,
                                             find_endpoint, get_stored_flows,
                                             match_field_dl_vlan,
                                             match_field_ip, prepare_json)


class Main(KytosNApp):
    """Main class of amlight/sdntrace_cp NApp.

    This application gets the list of flows from the switches
    and uses it to trace paths without using the data plane.
    """

    spec = load_spec(pathlib.Path(__file__).parent / "openapi.yml")

    def setup(self):
        """Replace the '__init__' method for the KytosNApp subclass.

        The setup method is automatically called by the controller when your
        application is loaded.

        """
        log.info("Starting Kytos SDNTrace CP App!")

    def execute(self):
        """This method is executed right after the setup method execution.

        You can also use this method in loop mode if you add to the above setup
        method a line like the following example:

            self.execute_as_loop(30)  # 30-second interval.
        """

    def shutdown(self):
        """This method is executed when your napp is unloaded.

        If you have some cleanup procedure, insert it here.
        """

    @rest('/v1/trace', methods=['PUT'])

    @validate_openapi(spec)
    def trace(self, request: Request) -> JSONResponse:
        """Trace a path."""
        result = []
        data = get_json_or_400(request, self.controller.loop)
        entries = convert_entries(data)
        if not entries:
            raise HTTPException(400, "Empty entries")
        try:
            stored_flows = get_stored_flows()
        except tenacity.RetryError as exc:
            raise HTTPException(424, "It couldn't get stored_flows") from exc
        try:
            result = self.tracepath(entries, stored_flows)
        except ValueError as exception:
            log.debug("tracepath error {exception}")
            raise exception
        return JSONResponse(prepare_json(result))

    @rest('/v1/traces', methods=['PUT'])

    @validate_openapi(spec)
    def get_traces(self, request: Request) -> JSONResponse:
        """For bulk requests."""
        data = get_json_or_400(request, self.controller.loop)
        entries = convert_list_entries(data)
        results = []
        try:
            stored_flows = get_stored_flows()
        except tenacity.RetryError as exc:
            raise HTTPException(424, "It couldn't get stored_flows") from exc
        for entry in entries:
            try:
                results.append(self.tracepath(entry, stored_flows))
            except ValueError as exception:
                log.debug("tracepath error {exception}")
                raise exception
        return JSONResponse(prepare_json(results))

    def tracepath(self, entries, stored_flows):
        """Trace a path for a packet represented by entries."""
        # pylint: disable=too-many-branches
        trace_result = []
        trace_type = 'starting'
        do_trace = True
        while do_trace:
            if 'dpid' not in entries or 'in_port' not in entries:
                break
            trace_step = {'in': {'dpid': entries['dpid'],
                                 'port': entries['in_port'],
                                 'time': str(datetime.now()),
                                 'type': trace_type}}
            if 'dl_vlan' in entries:
                trace_step['in'].update({'vlan': entries['dl_vlan'][-1]})

            switch = self.controller.get_switch_by_dpid(entries['dpid'])
            if not switch:
                trace_step['in']['type'] = 'last'
                trace_result.append(trace_step)
                break
            result = self.trace_step(switch, entries, stored_flows)
            if result:
                out = {'port': result['out_port']}
                if 'dl_vlan' in result['entries']:
                    out.update({'vlan': result['entries']['dl_vlan'][-1]})
                trace_step.update({
                    'out': out
                })
                if 'dpid' in result:
                    next_step = {'dpid': result['dpid'],
                                 'port': result['in_port']}
                    entries = result['entries']
                    entries['dpid'] = result['dpid']
                    entries['in_port'] = result['in_port']
                    if self.has_loop(next_step, trace_result):
                        trace_step['in']['type'] = 'loop'
                        do_trace = False
                    else:
                        trace_type = 'intermediary'
                else:
                    trace_step['in']['type'] = 'last'
                    do_trace = False
            else:
                # No match
                break
            if 'out' in trace_step and trace_step['out']:
                if self.check_loop_trace_step(trace_step, trace_result):
                    do_trace = False
            trace_result.append(trace_step)
        if len(trace_result) == 1 and \
                trace_result[0]['in']['type'] == 'starting':
            trace_result[0]['in']['type'] = 'last'
        return trace_result

    @staticmethod
    def check_loop_trace_step(trace_step, trace_result):
        """Check if there is a loop in the trace and add the step."""
        # outgoing interface is the same as the input interface
        if not trace_result and \
                trace_step['in']['type'] == 'last' and \
                trace_step['in']['port'] == trace_step['out']['port']:
            trace_step['in']['type'] = 'loop'
            return True
        if trace_result and \
                trace_result[0]['in']['dpid'] == trace_step['in']['dpid'] and \
                trace_result[0]['in']['port'] == trace_step['out']['port']:
            trace_step['in']['type'] = 'loop'
            return True
        return False

    @staticmethod
    def has_loop(trace_step, trace_result):
        """Check if there is a loop in the trace result."""
        for trace in trace_result:
            if trace['in']['dpid'] == trace_step['dpid'] and \
                            trace['in']['port'] == trace_step['port']:
                return True
        return False

    def trace_step(self, switch, entries, stored_flows):
        """Perform a trace step.

        Match the given fields against the switch's list of flows."""
        flow, entries, port = self.match_and_apply(
                                                    switch,
                                                    entries,
                                                    stored_flows
                                                )

        if not flow or not port:
            return None

        endpoint = find_endpoint(switch, port)
        if endpoint is None:
            log.warning(f"Port {port} not found on switch {switch}")
            return None
        endpoint = endpoint['endpoint']
        if endpoint is None:
            return {'out_port': port,
                    'entries': entries}

        return {'dpid': endpoint.switch.dpid,
                'in_port': endpoint.port_number,
                'out_port': port,
                'entries': entries}

    @classmethod
    def do_match(cls, flow, args, table_id):
        """Match a packet against this flow (OF1.3)."""
        # pylint: disable=consider-using-dict-items
        # pylint: disable=too-many-return-statements
        if ('match' not in flow['flow']) or (len(flow['flow']['match']) == 0):
            return False
        table_id_ = flow['flow'].get('table_id', 0)
        if table_id != table_id_:
            return False
        for name in flow['flow']['match']:
            field_flow = flow['flow']['match'][name]
            field = args.get(name)
            if name == 'dl_vlan':
                if not match_field_dl_vlan(field, field_flow):
                    return False
                continue
            # In the case of dl_vlan field, the match must be checked
            # even if this field is not in the packet args.
            if not field:
                return False
            if name in ('nw_src', 'nw_dst', 'ipv6_src', 'ipv6_dst'):
                if not match_field_ip(field, field_flow):
                    return False
                continue
            if field_flow != field:
                return False
        return flow

    # pylint: disable=too-many-arguments
    def match_flows(self, switch, table_id, args, stored_flows, many=True):
        """
        Match the packet in request against the stored flows from flow_manager.
        Try the match with each flow, in other. If many is True, tries the
        match with all flows, if False, tries until the first match.
        :param args: packet data
        :param many: Boolean, indicating whether to continue after matching the
                first flow or not
        :return: If many, the list of matched flows, or the matched flow
        """
        if switch.dpid not in stored_flows:
            return None
        response = []
        if switch.dpid not in stored_flows:
            return None
        try:
            for flow in stored_flows[switch.dpid]:
                match = Main.do_match(flow, args, table_id)
                if match:
                    if many:
                        response.append(match)
                    else:
                        response = match
                        break
        except AttributeError:
            return None
        if not many and isinstance(response, list):
            return None
        return response

    def process_tables(self, switch, table_id, args, stored_flows, actions):
        """Resolve the table context and get actions in the matched flow"""
        goto_table = False
        actions_ = []
        flow = self.match_flows(switch, table_id, args, stored_flows, False)
        if flow and 'actions' in flow['flow']:
            actions_ = flow['flow']['actions']
        elif flow and 'instructions' in flow['flow']:
            for instruction in flow['flow']['instructions']:
                if instruction['instruction_type'] == 'apply_actions':
                    actions_ = instruction['actions']
                elif instruction['instruction_type'] == 'goto_table':
                    table_id_ = instruction['table_id']
                    if table_id < table_id_:
                        table_id = table_id_
                        goto_table = True
                    else:
                        msg = f"Wrong table_id in {flow['flow']}: \
                            The packet can only been directed to a \
                                flow table number greather than {table_id}"
                        raise ValueError(msg) from ValueError
        actions.extend(actions_)
        return flow, actions, goto_table, table_id

    def match_and_apply(self, switch, args, stored_flows):
        """Match flows and apply actions.
        Match given packet (in args) against
        the stored flows (from flow_manager) and,
        if a match flow is found, apply its actions."""
        table_id = 0
        goto_table = True
        port = None
        actions = []
        while goto_table:
            try:
                flow, actions, goto_table, table_id = self.process_tables(
                    switch, table_id, args, stored_flows, actions)
            except ValueError as exception:
                raise exception
        if not flow or switch.ofp_version != '0x04':

            return flow, args, port

        for action in actions:
            action_type = action['action_type']
            if action_type == 'output':
                port = action['port']
            if action_type == 'push_vlan':
                if 'dl_vlan' not in args:
                    args['dl_vlan'] = []
                args['dl_vlan'].append(0)
            if action_type == 'pop_vlan':
                if 'dl_vlan' in args:
                    args['dl_vlan'].pop()
                    if len(args['dl_vlan']) == 0:
                        del args['dl_vlan']
            if action_type == 'set_vlan':
                args['dl_vlan'][-1] = action['vlan_id']
        return flow, args, port


1			"""Main module of amlight/sdntrace_cp Kytos Network Application.
2
3			Run tracepaths on OpenFlow in the Control Plane
4			"""
5
6	1		import pathlib
7	1		from datetime import datetime
8
9	1		import tenacity
10	1		from kytos.core import KytosNApp, log, rest
11	1		from kytos.core.helpers import load_spec, validate_openapi
12	1		from kytos.core.rest_api import (HTTPException, JSONResponse, Request,
13			get_json_or_400)
14	1		from napps.amlight.sdntrace_cp.utils import (convert_entries,
15			convert_list_entries,
16			find_endpoint, get_stored_flows,
17			match_field_dl_vlan,
18			match_field_ip, prepare_json)
19
20
21	1		class Main(KytosNApp):
22			"""Main class of amlight/sdntrace_cp NApp.
23
24			This application gets the list of flows from the switches
25			and uses it to trace paths without using the data plane.
26			"""
27
28	1		spec = load_spec(pathlib.Path(__file__).parent / "openapi.yml")
29
30	1		def setup(self):
31			"""Replace the '__init__' method for the KytosNApp subclass.
32
33			The setup method is automatically called by the controller when your
34			application is loaded.
35
36			"""
37	1		log.info("Starting Kytos SDNTrace CP App!")
38
39	1		def execute(self):
40			"""This method is executed right after the setup method execution.
41
42			You can also use this method in loop mode if you add to the above setup
43			method a line like the following example:
44
45			self.execute_as_loop(30) # 30-second interval.
46			"""
47
48	1		def shutdown(self):
49			"""This method is executed when your napp is unloaded.
50
51			If you have some cleanup procedure, insert it here.
52			"""
53
54	1	View Code Duplication	@rest('/v1/trace', methods=['PUT'])
			0 ignored issues – show Duplication introduced 2023-10-11 20:56 UTC by Report Bug Copy Issue Report This code seems to be duplicated in your project. Loading history...
55	1		@validate_openapi(spec)
56	1		def trace(self, request: Request) -> JSONResponse:
57			"""Trace a path."""
58	1		result = []
59	1		data = get_json_or_400(request, self.controller.loop)
60	1		entries = convert_entries(data)
61	1		if not entries:
62			raise HTTPException(400, "Empty entries")
63	1		try:
64	1		stored_flows = get_stored_flows()
65			except tenacity.RetryError as exc:
66			raise HTTPException(424, "It couldn't get stored_flows") from exc
67	1		try:
68	1		result = self.tracepath(entries, stored_flows)
69			except ValueError as exception:
70			log.debug("tracepath error {exception}")
71			raise exception
72	1		return JSONResponse(prepare_json(result))
73
74	1	View Code Duplication	@rest('/v1/traces', methods=['PUT'])
			0 ignored issues – show Duplication introduced 2023-10-11 20:56 UTC by Report Bug Copy Issue Report This code seems to be duplicated in your project. Loading history...
75	1		@validate_openapi(spec)
76	1		def get_traces(self, request: Request) -> JSONResponse:
77			"""For bulk requests."""
78	1		data = get_json_or_400(request, self.controller.loop)
79	1		entries = convert_list_entries(data)
80	1		results = []
81	1		try:
82	1		stored_flows = get_stored_flows()
83	1		except tenacity.RetryError as exc:
84			raise HTTPException(424, "It couldn't get stored_flows") from exc
85	1		for entry in entries:
86	1		try:
87	1		results.append(self.tracepath(entry, stored_flows))
88	1		except ValueError as exception:
89	1		log.debug("tracepath error {exception}")
90	1		raise exception
91	1		return JSONResponse(prepare_json(results))
92
93	1		def tracepath(self, entries, stored_flows):
94			"""Trace a path for a packet represented by entries."""
95			# pylint: disable=too-many-branches
96	1		trace_result = []
97	1		trace_type = 'starting'
98	1		do_trace = True
99	1		while do_trace:
100	1		if 'dpid' not in entries or 'in_port' not in entries:
101			break
102	1		trace_step = {'in': {'dpid': entries['dpid'],
103			'port': entries['in_port'],
104			'time': str(datetime.now()),
105			'type': trace_type}}
106	1		if 'dl_vlan' in entries:
107	1		trace_step['in'].update({'vlan': entries['dl_vlan'][-1]})
108
109	1		switch = self.controller.get_switch_by_dpid(entries['dpid'])
110	1		if not switch:
111	1		trace_step['in']['type'] = 'last'
112	1		trace_result.append(trace_step)
113	1		break
114	1		result = self.trace_step(switch, entries, stored_flows)
115	1		if result:
116	1		out = {'port': result['out_port']}
117	1		if 'dl_vlan' in result['entries']:
118	1		out.update({'vlan': result['entries']['dl_vlan'][-1]})
119	1		trace_step.update({
120			'out': out
121			})
122	1		if 'dpid' in result:
123	1		next_step = {'dpid': result['dpid'],
124			'port': result['in_port']}
125	1		entries = result['entries']
126	1		entries['dpid'] = result['dpid']
127	1		entries['in_port'] = result['in_port']
128	1		if self.has_loop(next_step, trace_result):
129	1		trace_step['in']['type'] = 'loop'
130	1		do_trace = False
131			else:
132	1		trace_type = 'intermediary'
133			else:
134	1		trace_step['in']['type'] = 'last'
135	1		do_trace = False
136			else:
137			# No match
138			break
139	1		if 'out' in trace_step and trace_step['out']:
140	1		if self.check_loop_trace_step(trace_step, trace_result):
141	1		do_trace = False
142	1		trace_result.append(trace_step)
143	1		if len(trace_result) == 1 and \
144			trace_result[0]['in']['type'] == 'starting':
145			trace_result[0]['in']['type'] = 'last'
146	1		return trace_result
147
148	1		@staticmethod
149	1		def check_loop_trace_step(trace_step, trace_result):
150			"""Check if there is a loop in the trace and add the step."""
151			# outgoing interface is the same as the input interface
152	1		if not trace_result and \
153			trace_step['in']['type'] == 'last' and \
154			trace_step['in']['port'] == trace_step['out']['port']:
155	1		trace_step['in']['type'] = 'loop'
156	1		return True
157	1		if trace_result and \
158			trace_result[0]['in']['dpid'] == trace_step['in']['dpid'] and \
159			trace_result[0]['in']['port'] == trace_step['out']['port']:
160	1		trace_step['in']['type'] = 'loop'
161	1		return True
162	1		return False
163
164	1		@staticmethod
165	1		def has_loop(trace_step, trace_result):
166			"""Check if there is a loop in the trace result."""
167	1		for trace in trace_result:
168	1		if trace['in']['dpid'] == trace_step['dpid'] and \
169			trace['in']['port'] == trace_step['port']:
170	1		return True
171	1		return False
172
173	1		def trace_step(self, switch, entries, stored_flows):
174			"""Perform a trace step.
175
176			Match the given fields against the switch's list of flows."""
177	1		flow, entries, port = self.match_and_apply(
178			switch,
179			entries,
180			stored_flows
181			)
182
183	1		if not flow or not port:
184	1		return None
185
186	1		endpoint = find_endpoint(switch, port)
187	1		if endpoint is None:
188			log.warning(f"Port {port} not found on switch {switch}")
189			return None
190	1		endpoint = endpoint['endpoint']
191	1		if endpoint is None:
192	1		return {'out_port': port,
193			'entries': entries}
194
195	1		return {'dpid': endpoint.switch.dpid,
196			'in_port': endpoint.port_number,
197			'out_port': port,
198			'entries': entries}
199
200	1		@classmethod
201	1		def do_match(cls, flow, args, table_id):
202			"""Match a packet against this flow (OF1.3)."""
203			# pylint: disable=consider-using-dict-items
204			# pylint: disable=too-many-return-statements
205	1		if ('match' not in flow['flow']) or (len(flow['flow']['match']) == 0):
206	1		return False
207	1		table_id_ = flow['flow'].get('table_id', 0)
208	1		if table_id != table_id_:
209	1		return False
210	1		for name in flow['flow']['match']:
211	1		field_flow = flow['flow']['match'][name]
212	1		field = args.get(name)
213	1		if name == 'dl_vlan':
214	1		if not match_field_dl_vlan(field, field_flow):
215	1		return False
216			continue
217			# In the case of dl_vlan field, the match must be checked
218			# even if this field is not in the packet args.
219	1		if not field:
220	1		return False
221	1		if name in ('nw_src', 'nw_dst', 'ipv6_src', 'ipv6_dst'):
222	1		if not match_field_ip(field, field_flow):
223	1		return False
224			continue
225	1		if field_flow != field:
226	1		return False
227	1		return flow
228
229			# pylint: disable=too-many-arguments
230	1		def match_flows(self, switch, table_id, args, stored_flows, many=True):
231			"""
232			Match the packet in request against the stored flows from flow_manager.
233			Try the match with each flow, in other. If many is True, tries the
234			match with all flows, if False, tries until the first match.
235			:param args: packet data
236			:param many: Boolean, indicating whether to continue after matching the
237			first flow or not
238			:return: If many, the list of matched flows, or the matched flow
239			"""
240	1		if switch.dpid not in stored_flows:
241	1		return None
242	1		response = []
243	1		if switch.dpid not in stored_flows:
244			return None
245	1		try:
246	1		for flow in stored_flows[switch.dpid]:
247	1		match = Main.do_match(flow, args, table_id)
248	1		if match:
249	1		if many:
250	1		response.append(match)
251			else:
252	1		response = match
253	1		break
254			except AttributeError:
255			return None
256	1		if not many and isinstance(response, list):
257	1		return None
258	1		return response
259
260	1		def process_tables(self, switch, table_id, args, stored_flows, actions):
261			"""Resolve the table context and get actions in the matched flow"""
262	1		goto_table = False
263	1		actions_ = []
264	1		flow = self.match_flows(switch, table_id, args, stored_flows, False)
265	1		if flow and 'actions' in flow['flow']:
266	1		actions_ = flow['flow']['actions']
267	1		elif flow and 'instructions' in flow['flow']:
268	1		for instruction in flow['flow']['instructions']:
269	1		if instruction['instruction_type'] == 'apply_actions':
270	1		actions_ = instruction['actions']
271	1		elif instruction['instruction_type'] == 'goto_table':
272	1		table_id_ = instruction['table_id']
273	1		if table_id < table_id_:
274	1		table_id = table_id_
275	1		goto_table = True
276			else:
277	1		msg = f"Wrong table_id in {flow['flow']}: \
278			The packet can only been directed to a \
279			flow table number greather than {table_id}"
280	1		raise ValueError(msg) from ValueError
281	1		actions.extend(actions_)
282	1		return flow, actions, goto_table, table_id
283
284	1		def match_and_apply(self, switch, args, stored_flows):
285			"""Match flows and apply actions.
286			Match given packet (in args) against
287			the stored flows (from flow_manager) and,
288			if a match flow is found, apply its actions."""
289	1		table_id = 0
290	1		goto_table = True
291	1		port = None
292	1		actions = []
293	1		while goto_table:
294	1		try:
295	1		flow, actions, goto_table, table_id = self.process_tables(
296			switch, table_id, args, stored_flows, actions)
297	1		except ValueError as exception:
298	1		raise exception
299	1		if not flow or switch.ofp_version != '0x04':
			0 ignored issues – show introduced 2023-09-11 17:46 UTC by Report Bug Copy Issue Report The variable `flow` does not seem to be defined in case the `while` loop on line `293` is not entered. Are you sure this can never be the case? Loading history...
300	1		return flow, args, port
301
302	1		for action in actions:
303	1		action_type = action['action_type']
304	1		if action_type == 'output':
305	1		port = action['port']
306	1		if action_type == 'push_vlan':
307	1		if 'dl_vlan' not in args:
308			args['dl_vlan'] = []
309	1		args['dl_vlan'].append(0)
310	1		if action_type == 'pop_vlan':
311	1		if 'dl_vlan' in args:
312	1		args['dl_vlan'].pop()
313	1		if len(args['dl_vlan']) == 0:
314	1		del args['dl_vlan']
315	1		if action_type == 'set_vlan':
316	1		args['dl_vlan'][-1] = action['vlan_id']
317			return flow, args, port
318

kytos-ng / sdntrace_cp

Pull Request — master (#108)

build.main.Main.do_match() C

Complexity

Size

Duplication

Code Coverage

Importance

How to fix Complexity

Complexity

Duplication Side-by-Side

Filter issues like