build.main.Main.match_flows() - Code Metrics - Inspection of "Merge pull request #96 from kytos-ng/fix/do_match" - kytos-ng/sdntrace_cp - Measure and Improve Code Quality continuously with Scrutinizer

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created 2023-05-10 20:31 UTC

build.main.Main.match_flows() C

↳ Parent: build.main

Complexity

Conditions

Size

Total Lines	30
Code Lines	19

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	14
CRAP Score	10.4768

Importance

Changes

Metric	Value
cc	9
eloc	19
nop	5
dl	0
loc	30
rs	6.6666
c	0
b	0
f	0
ccs	14
cts	19
cp	0.7368
crap	10.4768

"""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
        result = self.tracepath(entries, stored_flows)
        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:
            results.append(self.tracepath(entry, stored_flows))
        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:
                trace_step['in']['type'] = 'incomplete'
                do_trace = False
            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)
        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):
        """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
        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

    def match_flows(self, switch, args, stored_flows, many=True):
        # pylint: disable=bad-staticmethod-argument
        """
        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)
                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

    # pylint: disable=redefined-outer-name
    def match_and_apply(self, switch, args, stored_flows):
        # pylint: disable=bad-staticmethod-argument
        """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."""
        flow = self.match_flows(switch, args, stored_flows, False)
        port = None
        actions = []
        # pylint: disable=too-many-nested-blocks
        if not flow or switch.ofp_version != '0x04':
            return flow, args, port
        if 'actions' in flow['flow']:
            actions = flow['flow']['actions']
        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	@rest('/v1/trace', methods=['PUT'])
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	1	except tenacity.RetryError as exc:
66		raise HTTPException(424, "It couldn't get stored_flows") from exc
67	1	result = self.tracepath(entries, stored_flows)
68	1	return JSONResponse(prepare_json(result))
69
70	1	@rest('/v1/traces', methods=['PUT'])
71	1	@validate_openapi(spec)
72	1	def get_traces(self, request: Request) -> JSONResponse:
73		"""For bulk requests."""
74	1	data = get_json_or_400(request, self.controller.loop)
75	1	entries = convert_list_entries(data)
76	1	results = []
77	1	try:
78	1	stored_flows = get_stored_flows()
79	1	except tenacity.RetryError as exc:
80		raise HTTPException(424, "It couldn't get stored_flows") from exc
81	1	for entry in entries:
82	1	results.append(self.tracepath(entry, stored_flows))
83	1	return JSONResponse(prepare_json(results))
84
85	1	def tracepath(self, entries, stored_flows):
86		"""Trace a path for a packet represented by entries."""
87		# pylint: disable=too-many-branches
88	1	trace_result = []
89	1	trace_type = 'starting'
90	1	do_trace = True
91	1	while do_trace:
92	1	if 'dpid' not in entries or 'in_port' not in entries:
93		break
94	1	trace_step = {'in': {'dpid': entries['dpid'],
95		'port': entries['in_port'],
96		'time': str(datetime.now()),
97		'type': trace_type}}
98	1	if 'dl_vlan' in entries:
99	1	trace_step['in'].update({'vlan': entries['dl_vlan'][-1]})
100
101	1	switch = self.controller.get_switch_by_dpid(entries['dpid'])
102	1	if not switch:
103	1	trace_step['in']['type'] = 'last'
104	1	trace_result.append(trace_step)
105	1	break
106	1	result = self.trace_step(switch, entries, stored_flows)
107	1	if result:
108	1	out = {'port': result['out_port']}
109	1	if 'dl_vlan' in result['entries']:
110	1	out.update({'vlan': result['entries']['dl_vlan'][-1]})
111	1	trace_step.update({
112		'out': out
113		})
114	1	if 'dpid' in result:
115	1	next_step = {'dpid': result['dpid'],
116		'port': result['in_port']}
117	1	entries = result['entries']
118	1	entries['dpid'] = result['dpid']
119	1	entries['in_port'] = result['in_port']
120	1	if self.has_loop(next_step, trace_result):
121	1	trace_step['in']['type'] = 'loop'
122	1	do_trace = False
123		else:
124	1	trace_type = 'intermediary'
125		else:
126	1	trace_step['in']['type'] = 'last'
127	1	do_trace = False
128		else:
129	1	trace_step['in']['type'] = 'incomplete'
130	1	do_trace = False
131	1	if 'out' in trace_step and trace_step['out']:
132	1	if self.check_loop_trace_step(trace_step, trace_result):
133	1	do_trace = False
134	1	trace_result.append(trace_step)
135	1	return trace_result
136
137	1	@staticmethod
138	1	def check_loop_trace_step(trace_step, trace_result):
139		"""Check if there is a loop in the trace and add the step."""
140		# outgoing interface is the same as the input interface
141	1	if not trace_result and \
142		trace_step['in']['type'] == 'last' and \
143		trace_step['in']['port'] == trace_step['out']['port']:
144	1	trace_step['in']['type'] = 'loop'
145	1	return True
146	1	if trace_result and \
147		trace_result[0]['in']['dpid'] == trace_step['in']['dpid'] and \
148		trace_result[0]['in']['port'] == trace_step['out']['port']:
149	1	trace_step['in']['type'] = 'loop'
150	1	return True
151	1	return False
152
153	1	@staticmethod
154	1	def has_loop(trace_step, trace_result):
155		"""Check if there is a loop in the trace result."""
156	1	for trace in trace_result:
157	1	if trace['in']['dpid'] == trace_step['dpid'] and \
158		trace['in']['port'] == trace_step['port']:
159	1	return True
160	1	return False
161
162	1	def trace_step(self, switch, entries, stored_flows):
163		"""Perform a trace step.
164
165		Match the given fields against the switch's list of flows."""
166	1	flow, entries, port = self.match_and_apply(
167		switch,
168		entries,
169		stored_flows
170		)
171
172	1	if not flow or not port:
173	1	return None
174
175	1	endpoint = find_endpoint(switch, port)
176	1	if endpoint is None:
177		log.warning(f"Port {port} not found on switch {switch}")
178		return None
179	1	endpoint = endpoint['endpoint']
180	1	if endpoint is None:
181	1	return {'out_port': port,
182		'entries': entries}
183
184	1	return {'dpid': endpoint.switch.dpid,
185		'in_port': endpoint.port_number,
186		'out_port': port,
187		'entries': entries}
188
189	1	@classmethod
190	1	def do_match(cls, flow, args):
191		"""Match a packet against this flow (OF1.3)."""
192		# pylint: disable=consider-using-dict-items
193		# pylint: disable=too-many-return-statements
194	1	if ('match' not in flow['flow']) or (len(flow['flow']['match']) == 0):
195	1	return False
196	1	for name in flow['flow']['match']:
197	1	field_flow = flow['flow']['match'][name]
198	1	field = args.get(name)
199	1	if name == 'dl_vlan':
200	1	if not match_field_dl_vlan(field, field_flow):
201	1	return False
202		continue
203		# In the case of dl_vlan field, the match must be checked
204		# even if this field is not in the packet args.
205	1	if not field:
206		return False
207	1	if name in ('nw_src', 'nw_dst', 'ipv6_src', 'ipv6_dst'):
208		if not match_field_ip(field, field_flow):
209		return False
210		continue
211	1	if field_flow != field:
212	1	return False
213	1	return flow
214
215	1	def match_flows(self, switch, args, stored_flows, many=True):
216		# pylint: disable=bad-staticmethod-argument
217		"""
218		Match the packet in request against the stored flows from flow_manager.
219		Try the match with each flow, in other. If many is True, tries the
220		match with all flows, if False, tries until the first match.
221		:param args: packet data
222		:param many: Boolean, indicating whether to continue after matching the
223		first flow or not
224		:return: If many, the list of matched flows, or the matched flow
225		"""
226	1	if switch.dpid not in stored_flows:
227		return None
228	1	response = []
229	1	if switch.dpid not in stored_flows:
230		return None
231	1	try:
232	1	for flow in stored_flows[switch.dpid]:
233	1	match = Main.do_match(flow, args)
234	1	if match:
235	1	if many:
236		response.append(match)
237		else:
238	1	response = match
239	1	break
240		except AttributeError:
241		return None
242	1	if not many and isinstance(response, list):
243	1	return None
244	1	return response
245
246		# pylint: disable=redefined-outer-name
247	1	def match_and_apply(self, switch, args, stored_flows):
248		# pylint: disable=bad-staticmethod-argument
249		"""Match flows and apply actions.
250		Match given packet (in args) against
251		the stored flows (from flow_manager) and,
252		if a match flow is found, apply its actions."""
253	1	flow = self.match_flows(switch, args, stored_flows, False)
254	1	port = None
255	1	actions = []
256		# pylint: disable=too-many-nested-blocks
257	1	if not flow or switch.ofp_version != '0x04':
258	1	return flow, args, port
259	1	if 'actions' in flow['flow']:
260	1	actions = flow['flow']['actions']
261	1	for action in actions:
262	1	action_type = action['action_type']
263	1	if action_type == 'output':
264	1	port = action['port']
265	1	if action_type == 'push_vlan':
266	1	if 'dl_vlan' not in args:
267		args['dl_vlan'] = []
268	1	args['dl_vlan'].append(0)
269	1	if action_type == 'pop_vlan':
270	1	if 'dl_vlan' in args:
271	1	args['dl_vlan'].pop()
272	1	if len(args['dl_vlan']) == 0:
273	1	del args['dl_vlan']
274	1	if action_type == 'set_vlan':
275	1	args['dl_vlan'][-1] = action['vlan_id']
276		return flow, args, port
277

kytos-ng / sdntrace_cp

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build.main.Main.match_flows() C

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