Passed
Pull Request — master (#70)
by
unknown
03:11
created

build.main.Main.has_loop()   A

Complexity

Conditions 4

Size

Total Lines 8
Code Lines 7

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 6
CRAP Score 4

Importance

Changes 0
Metric Value
cc 4
eloc 7
nop 2
dl 0
loc 8
rs 10
c 0
b 0
f 0
ccs 6
cts 6
cp 1
crap 4
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
                                             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 1
            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
        return jsonify(prepare_json(results))
80
81 1
    def tracepath(self, entries, stored_flows):
82
        """Trace a path for a packet represented by entries."""
83 1
        self.last_id += 1
84 1
        trace_id = self.last_id
85 1
        trace_result = []
86 1
        trace_type = 'starting'
87 1
        do_trace = True
88 1
        while do_trace:
89 1
            if 'dpid' not in entries or 'in_port' not in entries:
90
                break
91 1
            trace_step = {'in': {'dpid': entries['dpid'],
92
                                 'port': entries['in_port'],
93
                                 'time': str(datetime.now()),
94
                                 'type': trace_type}}
95 1
            if 'dl_vlan' in entries:
96 1
                trace_step['in'].update({'vlan': entries['dl_vlan'][-1]})
97
98 1
            switch = self.controller.get_switch_by_dpid(entries['dpid'])
99 1
            if not switch:
100
                break
101 1
            result = self.trace_step(switch, entries, stored_flows)
102 1
            if result:
103 1
                out = {'port': result['out_port']}
104 1
                if 'dl_vlan' in result['entries']:
105 1
                    out.update({'vlan': result['entries']['dl_vlan'][-1]})
106 1
                trace_step.update({
107
                    'out': out
108
                })
109 1
                if 'dpid' in result:
110 1
                    next_step = {'dpid': result['dpid'],
111
                                 'port': result['in_port']}
112 1
                    if self.has_loop(next_step, trace_result):
113
                        # Loop
114 1
                        do_trace = False
115
                    else:
116 1
                        entries = result['entries']
117 1
                        entries['dpid'] = result['dpid']
118 1
                        entries['in_port'] = result['in_port']
119 1
                        trace_type = 'trace'
120
                else:
121 1
                    trace_step['in']['type'] = 'last'
122 1
                    do_trace = False
123
            else:
124
                # Incomplete
125
                break
126 1
            trace_result.append(trace_step)
127 1
        self.traces.update({
128
            trace_id: trace_result
129
        })
130 1
        return trace_result
131
132 1
    @staticmethod
133 1
    def has_loop(trace_step, trace_result):
134
        """Check if there is a loop in the trace result."""
135 1
        for trace in trace_result:
136 1
            if trace['in']['dpid'] == trace_step['dpid'] and \
137
                            trace['in']['port'] == trace_step['port']:
138 1
                return True
139 1
        return False
140
141 1
    def trace_step(self, switch, entries, stored_flows):
142
        """Perform a trace step.
143
144
        Match the given fields against the switch's list of flows."""
145 1
        flow, entries, port = self.match_and_apply(
146
                                                    switch,
147
                                                    entries,
148
                                                    stored_flows
149
                                                )
150
151 1
        if not flow or not port:
152 1
            return None
153
154 1
        endpoint = find_endpoint(switch, port)
155 1
        if endpoint is None:
156 1
            return {'out_port': port,
157
                    'entries': entries}
158
159 1
        return {'dpid': endpoint.switch.dpid,
160
                'in_port': endpoint.port_number,
161
                'out_port': port,
162
                'entries': entries}
163
164 1
    def update_circuits(self):
165
        """Update the list of circuits after a flow change."""
166
        # pylint: disable=unused-argument
167 1
        if settings.FIND_CIRCUITS_IN_FLOWS:
168 1
            self.automate.find_circuits()
169
170 1
    @classmethod
171 1
    def do_match(cls, flow, args):
172
        """Match a packet against this flow (OF1.3)."""
173
        # pylint: disable=consider-using-dict-items
174 1
        if ('match' not in flow['flow']) or (len(flow['flow']['match']) == 0):
175 1
            return False
176 1
        for name in flow['flow']['match']:
177 1
            field_flow = flow['flow']['match'][name]
178 1
            if name not in args:
179
                return False
180 1
            if name == 'dl_vlan':
181 1
                field = args[name][-1]
182
            else:
183 1
                field = args[name]
184 1
            if name not in ('ipv4_src', 'ipv4_dst', 'ipv6_src', 'ipv6_dst'):
185 1
                if field_flow != field:
186
                    return False
187
            else:
188
                packet_ip = int(ipaddress.ip_address(field))
189
                ip_addr = flow['flow']['match'][name]
190
                if packet_ip & ip_addr.netmask != ip_addr.address:
191
                    return False
192 1
        return flow
193
194 1
    def match_flows(self, switch, args, stored_flows, many=True):
195
        # pylint: disable=bad-staticmethod-argument
196
        """
197
        Match the packet in request against the stored flows from flow_manager.
198
        Try the match with each flow, in other. If many is True, tries the
199
        match with all flows, if False, tries until the first match.
200
        :param args: packet data
201
        :param many: Boolean, indicating whether to continue after matching the
202
                first flow or not
203
        :return: If many, the list of matched flows, or the matched flow
204
        """
205 1
        response = []
206 1
        if switch.dpid not in stored_flows:
207
            return None
208 1
        try:
209 1
            for flow in stored_flows[switch.dpid]:
210 1
                match = Main.do_match(flow, args)
211 1
                if match:
212 1
                    if many:
213
                        response.append(match)
214
                    else:
215 1
                        response = match
216 1
                        break
217
        except AttributeError:
218
            return None
219 1
        if not many and isinstance(response, list):
220 1
            return None
221 1
        return response
222
223
    # pylint: disable=redefined-outer-name
224 1
    def match_and_apply(self, switch, args, stored_flows):
225
        # pylint: disable=bad-staticmethod-argument
226
        """Match flows and apply actions.
227
        Match given packet (in args) against
228
        the stored flows (from flow_manager) and,
229
        if a match flow is found, apply its actions."""
230 1
        flow = self.match_flows(switch, args, stored_flows, False)
231 1
        port = None
232 1
        actions = []
233
        # pylint: disable=too-many-nested-blocks
234 1
        if not flow or switch.ofp_version != '0x04':
235 1
            return flow, args, port
236 1
        if 'actions' in flow['flow']:
237 1
            actions = flow['flow']['actions']
238 1
        for action in actions:
239 1
            action_type = action['action_type']
240 1
            if action_type == 'output':
241 1
                port = action['port']
242 1
            if action_type == 'push_vlan':
243 1
                if 'dl_vlan' not in args:
244
                    args['dl_vlan'] = []
245 1
                args['dl_vlan'].append(0)
246 1
            if action_type == 'pop_vlan':
247 1
                if 'dl_vlan' in args:
248 1
                    args['dl_vlan'].pop()
249 1
                    if len(args['dl_vlan']) == 0:
250 1
                        del args['dl_vlan']
251 1
            if action_type == 'set_vlan':
252 1
                args['dl_vlan'][-1] = action['vlan_id']
253
        return flow, args, port
254