Passed
Push — master ( d2ced9...6052f7 )
by
unknown
04:49 queued 14s
created

build.main.Main.do_match()   C

Complexity

Conditions 11

Size

Total Lines 28
Code Lines 24

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 18
CRAP Score 12.8905

Importance

Changes 0
Metric Value
cc 11
eloc 24
nop 3
dl 0
loc 28
rs 5.4
c 0
b 0
f 0
ccs 18
cts 24
cp 0.75
crap 12.8905

How to fix   Complexity   

Complexity

Complex classes like build.main.Main.do_match() often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.

Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.

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 ipaddress
7 1
from datetime import datetime
8
9 1
from flask import jsonify, request
10 1
from kytos.core import KytosNApp, log, rest
11 1
from napps.amlight.sdntrace_cp import settings
12 1
from napps.amlight.sdntrace_cp.automate import Automate
13 1
from napps.amlight.sdntrace_cp.utils import (convert_entries,
14
                                             convert_list_entries,
15
                                             find_endpoint, get_stored_flows,
16
                                             match_field_dl_vlan, prepare_json)
17
18
19 1
class Main(KytosNApp):
20
    """Main class of amlight/sdntrace_cp NApp.
21
22
    This application gets the list of flows from the switches
23
    and uses it to trace paths without using the data plane.
24
    """
25
26 1
    def setup(self):
27
        """Replace the '__init__' method for the KytosNApp subclass.
28
29
        The setup method is automatically called by the controller when your
30
        application is loaded.
31
32
        """
33 1
        log.info("Starting Kytos SDNTrace CP App!")
34
35 1
        self.traces = {}
36 1
        self.last_id = 30000
37 1
        self.automate = Automate(self)
38 1
        self.automate.schedule_traces()
39 1
        self.automate.schedule_important_traces()
40
41 1
    def execute(self):
42
        """This method is executed right after the setup method execution.
43
44
        You can also use this method in loop mode if you add to the above setup
45
        method a line like the following example:
46
47
            self.execute_as_loop(30)  # 30-second interval.
48
        """
49
50 1
    def shutdown(self):
51
        """This method is executed when your napp is unloaded.
52
53
        If you have some cleanup procedure, insert it here.
54
        """
55
        self.automate.unschedule_ids()
56
        self.automate.sheduler_shutdown(wait=False)
57
58 1
    @rest('/trace', methods=['PUT'])
59 1
    def trace(self):
60
        """Trace a path."""
61 1
        result = []
62 1
        entries = request.get_json()
63 1
        entries = convert_entries(entries)
64 1
        if not entries:
65
            return "Bad request", 400
66 1
        stored_flows = get_stored_flows()
67 1
        result = self.tracepath(entries, stored_flows)
68 1
        return jsonify(prepare_json(result))
69
70 1
    @rest('/traces', methods=['PUT'])
71 1
    def get_traces(self):
72
        """For bulk requests."""
73 1
        entries = request.get_json()
74 1
        entries = convert_list_entries(entries)
75 1
        stored_flows = get_stored_flows()
76 1
        results = []
77 1
        for entry in entries:
78 1
            results.append(self.tracepath(entry, stored_flows))
79 1
        temp = prepare_json(results)
80 1
        return jsonify(temp)
81
82 1
    def tracepath(self, entries, stored_flows):
83
        """Trace a path for a packet represented by entries."""
84
        # pylint: disable=too-many-branches
85 1
        self.last_id += 1
86 1
        trace_id = self.last_id
87 1
        trace_result = []
88 1
        trace_type = 'starting'
89 1
        do_trace = True
90 1
        while do_trace:
91 1
            if 'dpid' not in entries or 'in_port' not in entries:
92 1
                break
93 1
            trace_step = {'in': {'dpid': entries['dpid'],
94
                                 'port': entries['in_port'],
95
                                 'time': str(datetime.now()),
96
                                 'type': trace_type}}
97 1
            if 'dl_vlan' in entries:
98 1
                trace_step['in'].update({'vlan': entries['dl_vlan'][-1]})
99
100 1
            switch = self.controller.get_switch_by_dpid(entries['dpid'])
101 1
            if not switch:
102 1
                trace_step['in']['type'] = 'last'
103 1
                trace_result.append(trace_step)
104 1
                break
105 1
            result = self.trace_step(switch, entries, stored_flows)
106 1
            if result:
107 1
                out = {'port': result['out_port']}
108 1
                if 'dl_vlan' in result['entries']:
109 1
                    out.update({'vlan': result['entries']['dl_vlan'][-1]})
110 1
                trace_step.update({
111
                    'out': out
112
                })
113 1
                if 'dpid' in result:
114 1
                    next_step = {'dpid': result['dpid'],
115
                                 'port': result['in_port']}
116 1
                    entries = result['entries']
117 1
                    entries['dpid'] = result['dpid']
118 1
                    entries['in_port'] = result['in_port']
119 1
                    if self.has_loop(next_step, trace_result):
120 1
                        trace_step['in']['type'] = 'loop'
121 1
                        do_trace = False
122
                    else:
123 1
                        trace_type = 'intermediary'
124
                else:
125 1
                    trace_step['in']['type'] = 'last'
126 1
                    do_trace = False
127
            else:
128 1
                trace_step['in']['type'] = 'incomplete'
129 1
                do_trace = False
130 1
            if 'out' in trace_step and trace_step['out']:
131 1
                if self.check_loop_trace_step(trace_step, trace_result):
132 1
                    do_trace = False
133 1
            trace_result.append(trace_step)
134 1
        self.traces.update({
135
            trace_id: trace_result
136
        })
137 1
        return trace_result
138
139 1
    @staticmethod
140 1
    def check_loop_trace_step(trace_step, trace_result):
141
        """Check if there is a loop in the trace and add the step."""
142
        # outgoing interface is the same as the input interface
143 1
        if not trace_result and \
144
                trace_step['in']['type'] == 'last' and \
145
                trace_step['in']['port'] == trace_step['out']['port']:
146 1
            trace_step['in']['type'] = 'loop'
147 1
            return True
148 1
        if trace_result and \
149
                trace_result[0]['in']['dpid'] == trace_step['in']['dpid'] and \
150
                trace_result[0]['in']['port'] == trace_step['out']['port']:
151 1
            trace_step['in']['type'] = 'loop'
152 1
            return True
153 1
        return False
154
155 1
    @staticmethod
156 1
    def has_loop(trace_step, trace_result):
157
        """Check if there is a loop in the trace result."""
158 1
        for trace in trace_result:
159 1
            if trace['in']['dpid'] == trace_step['dpid'] and \
160
                            trace['in']['port'] == trace_step['port']:
161 1
                return True
162 1
        return False
163
164 1
    def trace_step(self, switch, entries, stored_flows):
165
        """Perform a trace step.
166
167
        Match the given fields against the switch's list of flows."""
168 1
        flow, entries, port = self.match_and_apply(
169
                                                    switch,
170
                                                    entries,
171
                                                    stored_flows
172
                                                )
173
174 1
        if not flow or not port:
175 1
            return None
176
177 1
        endpoint = find_endpoint(switch, port)
178 1
        if endpoint is None:
179 1
            return {'out_port': port,
180
                    'entries': entries}
181
182 1
        return {'dpid': endpoint.switch.dpid,
183
                'in_port': endpoint.port_number,
184
                'out_port': port,
185
                'entries': entries}
186
187 1
    def update_circuits(self):
188
        """Update the list of circuits after a flow change."""
189
        # pylint: disable=unused-argument
190 1
        if settings.FIND_CIRCUITS_IN_FLOWS:
191 1
            self.automate.find_circuits()
192
193 1
    @classmethod
194 1
    def do_match(cls, flow, args):
195
        """Match a packet against this flow (OF1.3)."""
196
        # pylint: disable=consider-using-dict-items
197
        # pylint: disable=too-many-return-statements
198 1
        if ('match' not in flow['flow']) or (len(flow['flow']['match']) == 0):
199 1
            return False
200 1
        for name in flow['flow']['match']:
201 1
            field_flow = flow['flow']['match'][name]
202 1
            if name == 'dl_vlan':
203 1
                field = args.get(name)
204 1
                if field:
205 1
                    field = field[-1]
206 1
                if not match_field_dl_vlan(field, field_flow):
207 1
                    return False
208
                continue
209 1
            if name not in args:
210
                return False
211 1
            field = args[name]
212 1
            if name not in ('ipv4_src', 'ipv4_dst', 'ipv6_src', 'ipv6_dst'):
213 1
                if field_flow != field:
214 1
                    return False
215
            else:
216
                packet_ip = int(ipaddress.ip_address(field))
217
                ip_addr = flow['flow']['match'][name]
218
                if packet_ip & ip_addr.netmask != ip_addr.address:
219
                    return False
220 1
        return flow
221
222 1
    def match_flows(self, switch, args, stored_flows, many=True):
223
        # pylint: disable=bad-staticmethod-argument
224
        """
225
        Match the packet in request against the stored flows from flow_manager.
226
        Try the match with each flow, in other. If many is True, tries the
227
        match with all flows, if False, tries until the first match.
228
        :param args: packet data
229
        :param many: Boolean, indicating whether to continue after matching the
230
                first flow or not
231
        :return: If many, the list of matched flows, or the matched flow
232
        """
233 1
        if switch.dpid not in stored_flows:
234
            return None
235 1
        response = []
236 1
        if switch.dpid not in stored_flows:
237
            return None
238 1
        try:
239 1
            for flow in stored_flows[switch.dpid]:
240 1
                match = Main.do_match(flow, args)
241 1
                if match:
242 1
                    if many:
243
                        response.append(match)
244
                    else:
245 1
                        response = match
246 1
                        break
247
        except AttributeError:
248
            return None
249 1
        if not many and isinstance(response, list):
250 1
            return None
251 1
        return response
252
253
    # pylint: disable=redefined-outer-name
254 1
    def match_and_apply(self, switch, args, stored_flows):
255
        # pylint: disable=bad-staticmethod-argument
256
        """Match flows and apply actions.
257
        Match given packet (in args) against
258
        the stored flows (from flow_manager) and,
259
        if a match flow is found, apply its actions."""
260 1
        flow = self.match_flows(switch, args, stored_flows, False)
261 1
        port = None
262 1
        actions = []
263
        # pylint: disable=too-many-nested-blocks
264 1
        if not flow or switch.ofp_version != '0x04':
265 1
            return flow, args, port
266 1
        if 'actions' in flow['flow']:
267 1
            actions = flow['flow']['actions']
268 1
        for action in actions:
269 1
            action_type = action['action_type']
270 1
            if action_type == 'output':
271 1
                port = action['port']
272 1
            if action_type == 'push_vlan':
273 1
                if 'dl_vlan' not in args:
274
                    args['dl_vlan'] = []
275 1
                args['dl_vlan'].append(0)
276 1
            if action_type == 'pop_vlan':
277 1
                if 'dl_vlan' in args:
278 1
                    args['dl_vlan'].pop()
279 1
                    if len(args['dl_vlan']) == 0:
280 1
                        del args['dl_vlan']
281 1
            if action_type == 'set_vlan':
282 1
                args['dl_vlan'][-1] = action['vlan_id']
283
        return flow, args, port
284