Passed
Pull Request — master (#75)
by
unknown
03:12
created

build.main.Main.match_flows()   B

Complexity

Conditions 7

Size

Total Lines 26
Code Lines 15

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 12
CRAP Score 7.392

Importance

Changes 0
Metric Value
cc 7
eloc 15
nop 5
dl 0
loc 26
rs 8
c 0
b 0
f 0
ccs 12
cts 15
cp 0.8
crap 7.392
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
        entries = request.get_json()
62 1
        entries = convert_entries(entries)
63 1
        stored_flows = get_stored_flows()
64 1
        result = self.tracepath(entries, stored_flows)
65 1
        return jsonify(prepare_json(result))
66
67 1
    @rest('/traces', methods=['PUT'])
68 1
    def get_traces(self):
69
        """For bulk requests."""
70 1
        entries = request.get_json()
71 1
        entries = convert_list_entries(entries)
72 1
        stored_flows = get_stored_flows()
73 1
        results = []
74 1
        for entry in entries:
75 1
            results.append(self.tracepath(entry, stored_flows))
76 1
        return jsonify(prepare_json(results))
77
78 1
    def tracepath(self, entries, stored_flows):
79
        """Trace a path for a packet represented by entries."""
80 1
        self.last_id += 1
81 1
        trace_id = self.last_id
82 1
        trace_result = []
83 1
        trace_type = 'starting'
84 1
        do_trace = True
85 1
        while do_trace:
86 1
            trace_step = {'in': {'dpid': entries['dpid'],
87
                                 'port': entries['in_port'],
88
                                 'time': str(datetime.now()),
89
                                 'type': trace_type}}
90 1
            if 'dl_vlan' in entries:
91 1
                trace_step['in'].update({'vlan': entries['dl_vlan'][-1]})
92 1
            switch = self.controller.get_switch_by_dpid(entries['dpid'])
93 1
            if (switch is None) or \
94
                    (switch.dpid not in stored_flows):
95
                result = None
96
            else:
97 1
                result = self.trace_step(switch, entries, stored_flows)
98 1
            if result:
99 1
                out = {'port': result['out_port']}
100 1
                if 'dl_vlan' in result['entries']:
101 1
                    out.update({'vlan': result['entries']['dl_vlan'][-1]})
102 1
                trace_step.update({
103
                    'out': out
104
                })
105 1
                if 'dpid' in result:
106 1
                    next_step = {'dpid': result['dpid'],
107
                                 'port': result['in_port']}
108 1
                    if self.has_loop(next_step, trace_result):
109 1
                        do_trace = False
110
                    else:
111 1
                        entries = result['entries']
112 1
                        entries['dpid'] = result['dpid']
113 1
                        entries['in_port'] = result['in_port']
114 1
                        trace_type = 'trace'
115
                else:
116 1
                    do_trace = False
117
            else:
118
                break
119 1
            trace_result.append(trace_step)
120 1
        self.traces.update({
121
            trace_id: trace_result
122
        })
123 1
        return trace_result
124
125 1
    @staticmethod
126 1
    def has_loop(trace_step, trace_result):
127
        """Check if there is a loop in the trace result."""
128 1
        for trace in trace_result:
129 1
            if trace['in']['dpid'] == trace_step['dpid'] and \
130
                            trace['in']['port'] == trace_step['port']:
131 1
                return True
132 1
        return False
133
134 1
    def trace_step(self, switch, entries, stored_flows):
135
        """Perform a trace step.
136
137
        Match the given fields against the switch's list of flows."""
138 1
        flow, entries, port = self.match_and_apply(
139
                                                    switch,
140
                                                    entries,
141
                                                    stored_flows
142
                                                )
143
144 1
        if not flow or not port:
145 1
            return None
146
147 1
        endpoint = find_endpoint(switch, port)
148 1
        if endpoint is None:
149 1
            return {'out_port': port,
150
                    'entries': entries}
151
152 1
        return {'dpid': endpoint.switch.dpid,
153
                'in_port': endpoint.port_number,
154
                'out_port': port,
155
                'entries': entries}
156
157 1
    def update_circuits(self):
158
        """Update the list of circuits after a flow change."""
159
        # pylint: disable=unused-argument
160 1
        if settings.FIND_CIRCUITS_IN_FLOWS:
161 1
            self.automate.find_circuits()
162
163 1
    @classmethod
164 1
    def do_match(cls, flow, args):
165
        """Match a packet against this flow (OF1.3)."""
166
        # pylint: disable=consider-using-dict-items
167 1
        if ('match' not in flow['flow']) or (len(flow['flow']['match']) == 0):
168 1
            return False
169 1
        for name in flow['flow']['match']:
170 1
            field_flow = flow['flow']['match'][name]
171 1
            if name not in args:
172
                return False
173 1
            if name == 'dl_vlan':
174 1
                field = args[name][-1]
175
            else:
176 1
                field = args[name]
177 1
            if name not in ('ipv4_src', 'ipv4_dst', 'ipv6_src', 'ipv6_dst'):
178 1
                if field_flow != field:
179
                    return False
180
            else:
181
                packet_ip = int(ipaddress.ip_address(field))
182
                ip_addr = flow['flow']['match'][name]
183
                if packet_ip & ip_addr.netmask != ip_addr.address:
184
                    return False
185 1
        return flow
186
187 1
    def match_flows(self, switch, args, stored_flows, many=True):
188
        # pylint: disable=bad-staticmethod-argument
189
        """
190
        Match the packet in request against the stored flows from flow_manager.
191
        Try the match with each flow, in other. If many is True, tries the
192
        match with all flows, if False, tries until the first match.
193
        :param args: packet data
194
        :param many: Boolean, indicating whether to continue after matching the
195
                first flow or not
196
        :return: If many, the list of matched flows, or the matched flow
197
        """
198 1
        response = []
199 1
        try:
200 1
            for flow in stored_flows[switch.dpid]:
201 1
                match = Main.do_match(flow, args)
202 1
                if match:
203 1
                    if many:
204
                        response.append(match)
205
                    else:
206 1
                        response = match
207 1
                        break
208
        except AttributeError:
209
            return None
210 1
        if not many and isinstance(response, list):
211 1
            return None
212 1
        return response
213
214
    # pylint: disable=redefined-outer-name
215 1
    def match_and_apply(self, switch, args, stored_flows):
216
        # pylint: disable=bad-staticmethod-argument
217
        """Match flows and apply actions.
218
        Match given packet (in args) against
219
        the stored flows (from flow_manager) and,
220
        if a match flow is found, apply its actions."""
221 1
        flow = self.match_flows(switch, args, stored_flows, False)
222 1
        port = None
223 1
        actions = None
224
        # pylint: disable=too-many-nested-blocks
225 1
        if not flow or switch.ofp_version != '0x04':
226 1
            return flow, args, port
227 1
        actions = flow['flow']['actions']
228 1
        for action in actions:
229 1
            action_type = action['action_type']
230 1
            if action_type == 'output':
231 1
                port = action['port']
232 1
            if action_type == 'push_vlan':
233 1
                if 'dl_vlan' not in args:
234
                    args['dl_vlan'] = []
235 1
                args['dl_vlan'].append(0)
236 1
            if action_type == 'pop_vlan':
237 1
                if 'dl_vlan' in args:
238 1
                    args['dl_vlan'].pop()
239 1
                    if len(args['dl_vlan']) == 0:
240 1
                        del args['dl_vlan']
241 1
            if action_type == 'set_vlan':
242 1
                args['dl_vlan'][-1] = action['vlan_id']
243
        return flow, args, port
244