aboutsummaryrefslogtreecommitdiffstats
path: root/resources/libraries/python/topology.py
blob: a5a446008ba3da99af5a03360cc621f0a9d3a97e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
# Copyright (c) 2016 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Defines nodes and topology structure."""

from collections import Counter

from yaml import load

from robot.api import logger
from robot.libraries.BuiltIn import BuiltIn, RobotNotRunningError
from robot.api.deco import keyword

__all__ = ["DICT__nodes", 'Topology']


def load_topo_from_yaml():
    """Load topology from file defined in "${TOPOLOGY_PATH}" variable.

    :returns: Nodes from loaded topology.
    """
    try:
        topo_path = BuiltIn().get_variable_value("${TOPOLOGY_PATH}")
    except RobotNotRunningError:
        return ''

    with open(topo_path) as work_file:
        return load(work_file.read())['nodes']


# pylint: disable=invalid-name

class NodeType(object):
    """Defines node types used in topology dictionaries."""
    # Device Under Test (this node has VPP running on it)
    DUT = 'DUT'
    # Traffic Generator (this node has traffic generator on it)
    TG = 'TG'
    # Virtual Machine (this node running on DUT node)
    VM = 'VM'


class NodeSubTypeTG(object):
    """Defines node sub-type TG - traffic generator."""
    # T-Rex traffic generator
    TREX = 'TREX'
    # Moongen
    MOONGEN = 'MOONGEN'
    # IxNetwork
    IXNET = 'IXNET'

DICT__nodes = load_topo_from_yaml()


class Topology(object):
    """Topology data manipulation and extraction methods.

    Defines methods used for manipulation and extraction of data from
    the active topology.

    "Active topology" contains initially data from the topology file and can be
    extended with additional data from the DUTs like internal interface indexes
    or names. Additional data which can be filled to the active topology are
        - additional internal representation (index, name, ...)
        - operational data (dynamic ports)

    To access the port data it is recommended to use a port key because the key
    does not rely on the data retrieved from nodes, this allows to call most of
    the methods without having filled active topology with internal nodes data.
    """

    @staticmethod
    def add_new_port(node, ptype):
        """Add new port to the node to active topology.

        :param node: Node to add new port on.
        :param ptype: Port type, used as key prefix.
        :type node: dict
        :type ptype: str
        :returns: Port key or None
        :rtype: string or None
        """
        max_ports = 1000000
        iface = None
        for i in range(1, max_ports):
            if node['interfaces'].get(str(ptype) + str(i)) is None:
                iface = str(ptype) + str(i)
                node['interfaces'][iface] = dict()
                break
        return iface

    @staticmethod
    def remove_port(node, iface_key):
        """Remove required port from active topology.

        :param node: Node to remove port on.
        :param: iface_key: Topology key of the interface.
        :type node: dict
        :type iface_key: str
        :returns: Nothing
        """
        try:
            node['interfaces'].pop(iface_key)
        except KeyError:
            pass

    @staticmethod
    def remove_all_ports(node, ptype):
        """Remove all ports with ptype as prefix.

        :param node: Node to remove ports on.
        :param: ptype: Port type, used as key prefix.
        :type node: dict
        :type ptype: str
        :returns: Nothing
        """
        for if_key in list(node['interfaces']):
            if if_key.startswith(str(ptype)):
                node['interfaces'].pop(if_key)

    @staticmethod
    def remove_all_added_ports_on_all_duts_from_topology(nodes):
        """Remove all added ports on all DUT nodes in the topology.

        :param nodes: Nodes in the topology.
        :type nodes: dict
        :returns: Nothing
        """
        port_types = ('subinterface', 'vlan_subif',  'memif', 'tap', 'vhost',
                      'loopback', 'gre_tunnel', 'vxlan_tunnel')

        for node_data in nodes.values():
            if node_data['type'] == NodeType.DUT:
                for ptype in port_types:
                    Topology.remove_all_ports(node_data, ptype)

    @staticmethod
    def update_interface_sw_if_index(node, iface_key, sw_if_index):
        """Update sw_if_index on the interface from the node.

        :param node: Node to update sw_if_index on.
        :param iface_key: Topology key of the interface.
        :param sw_if_index: Internal index to store.
        :type node: dict
        :type iface_key: str
        :type sw_if_index: int
        """
        node['interfaces'][iface_key]['vpp_sw_index'] = int(sw_if_index)

    @staticmethod
    def update_interface_name(node, iface_key, name):
        """Update name on the interface from the node.

        :param node: Node to update name on.
        :param iface_key: Topology key of the interface.
        :param name: Interface name to store.
        :type node: dict
        :type iface_key: str
        :type name: str
        """
        node['interfaces'][iface_key]['name'] = str(name)

    @staticmethod
    def update_interface_mac_address(node, iface_key, mac_address):
        """Update mac_address on the interface from the node.

        :param node: Node to update MAC on.
        :param iface_key: Topology key of the interface.
        :param mac_address: MAC address.
        :type node: dict
        :type iface_key: str
        :type mac_address: str
        """
        node['interfaces'][iface_key]['mac_address'] = str(mac_address)

    @staticmethod
    def update_interface_vhost_socket(node, iface_key, vhost_socket):
        """Update vhost socket name on the interface from the node.

        :param node: Node to update socket name on.
        :param iface_key: Topology key of the interface.
        :param vhost_socket: Path to named socket on node.
        :type node: dict
        :type iface_key: str
        :type vhost_socket: str
        """
        node['interfaces'][iface_key]['vhost_socket'] = str(vhost_socket)

    @staticmethod
    def update_interface_memif_socket(node, iface_key, memif_socket):
        """Update memif socket name on the interface from the node.

        :param node: Node to update socket name on.
        :param iface_key: Topology key of the interface.
        :param memif_socket: Path to named socket on node.
        :type node: dict
        :type iface_key: str
        :type memif_socket: str
        """
        node['interfaces'][iface_key]['memif_socket'] = str(memif_socket)

    @staticmethod
    def update_interface_memif_id(node, iface_key, memif_id):
        """Update memif ID on the interface from the node.

        :param node: Node to update memif ID on.
        :param iface_key: Topology key of the interface.
        :param memif_id: Memif interface ID.
        :type node: dict
        :type iface_key: str
        :type memif_id: str
        """
        node['interfaces'][iface_key]['memif_id'] = str(memif_id)

    @staticmethod
    def update_interface_memif_role(node, iface_key, memif_role):
        """Update memif role on the interface from the node.

        :param node: Node to update memif role on.
        :param iface_key: Topology key of the interface.
        :param memif_role: Memif role.
        :type node: dict
        :type iface_key: str
        :type memif_role: str
        """
        node['interfaces'][iface_key]['memif_role'] = str(memif_role)

    @staticmethod
    def update_interface_tap_dev_name(node, iface_key, dev_name):
        """Update device name on the tap interface from the node.

        :param node: Node to update tap device name on.
        :param iface_key: Topology key of the interface.
        :param dev_name: Device name of the tap interface.
        :type node: dict
        :type iface_key: str
        :type dev_name: str
        :returns: Nothing
        """
        node['interfaces'][iface_key]['dev_name'] = str(dev_name)

    @staticmethod
    def get_node_by_hostname(nodes, hostname):
        """Get node from nodes of the topology by hostname.

        :param nodes: Nodes of the test topology.
        :param hostname: Host name.
        :type nodes: dict
        :type hostname: str
        :returns: Node dictionary or None if not found.
        """
        for node in nodes.values():
            if node['host'] == hostname:
                return node

        return None

    @staticmethod
    def get_links(nodes):
        """Get list of links(networks) in the topology.

        :param nodes: Nodes of the test topology.
        :type nodes: dict
        :returns: Links in the topology.
        :rtype: list
        """
        links = []

        for node in nodes.values():
            for interface in node['interfaces'].values():
                link = interface.get('link')
                if link is not None:
                    if link not in links:
                        links.append(link)

        return links

    @staticmethod
    def _get_interface_by_key_value(node, key, value):
        """Return node interface key from topology file
        according to key and value.

        :param node: The node dictionary.
        :param key: Key by which to select the interface.
        :param value: Value that should be found using the key.
        :type node: dict
        :type key: string
        :type value: string
        :returns: Interface key from topology file
        :rtype: string
        """
        interfaces = node['interfaces']
        retval = None
        for if_key, if_val in interfaces.iteritems():
            k_val = if_val.get(key)
            if k_val is not None:
                if k_val == value:
                    retval = if_key
                    break
        return retval

    @staticmethod
    def get_interface_by_name(node, iface_name):
        """Return interface key based on name from DUT/TG.

        This method returns interface key based on interface name
        retrieved from the DUT, or TG.

        :param node: The node topology dictionary.
        :param iface_name: Interface name (string form).
        :type node: dict
        :type iface_name: string
        :returns: Interface key.
        :rtype: str
        """
        return Topology._get_interface_by_key_value(node, "name", iface_name)

    @staticmethod
    def get_interface_by_link_name(node, link_name):
        """Return interface key of link on node.

        This method returns the interface name associated with a given link
        for a given node.

        :param node: The node topology dictionary.
        :param link_name: Name of the link that a interface is connected to.
        :type node: dict
        :type link_name: string
        :returns: Interface key of the interface connected to the given link.
        :rtype: str
        """
        return Topology._get_interface_by_key_value(node, "link", link_name)

    def get_interfaces_by_link_names(self, node, link_names):
        """Return dictionary of dictionaries {"interfaceN", interface name}.

        This method returns the interface names associated with given links
        for a given node.

        :param node: The node topology directory.
        :param link_names: List of names of the link that a interface is
        connected to.
        :type node: dict
        :type link_names: list
        :returns: Dictionary of interface names that are connected to the given
        links.
        :rtype: dict
        """
        retval = {}
        interface_key_tpl = "interface{}"
        interface_number = 1
        for link_name in link_names:
            interface = self.get_interface_by_link_name(node, link_name)
            interface_name = self.get_interface_name(node, interface)
            interface_key = interface_key_tpl.format(str(interface_number))
            retval[interface_key] = interface_name
            interface_number += 1
        return retval

    @staticmethod
    def get_interface_by_sw_index(node, sw_index):
        """Return interface name of link on node.

        This method returns the interface name associated with a software
        interface index assigned to the interface by vpp for a given node.

        :param node: The node topology dictionary.
        :param sw_index: Sw_index of the link that a interface is connected to.
        :type node: dict
        :type sw_index: int
        :returns: Interface name of the interface connected to the given link.
        :rtype: str
        """
        return Topology._get_interface_by_key_value(node, "vpp_sw_index",
                                                    sw_index)

    @staticmethod
    def get_interface_sw_index(node, iface_key):
        """Get VPP sw_if_index for the interface using interface key.

        :param node: Node to get interface sw_if_index on.
        :param iface_key: Interface key from topology file, or sw_index.
        :type node: dict
        :type iface_key: str/int
        :returns: Return sw_if_index or None if not found.
        """
        try:
            if isinstance(iface_key, basestring):
                return node['interfaces'][iface_key].get('vpp_sw_index')
            # TODO: use only iface_key, do not use integer
            else:
                return int(iface_key)
        except (KeyError, ValueError):
            return None

    @staticmethod
    def get_interface_sw_index_by_name(node, iface_name):
        """Get VPP sw_if_index for the interface using interface name.

        :param node: Node to get interface sw_if_index on.
        :param iface_name: Interface name.
        :type node: dict
        :type iface_name: str
        :returns: Return sw_if_index or None if not found.
        :raises TypeError: If provided interface name is not a string.
        """
        try:
            if isinstance(iface_name, basestring):
                iface_key = Topology.get_interface_by_name(node, iface_name)
                return node['interfaces'][iface_key].get('vpp_sw_index')
            else:
                raise TypeError("Interface name must be a string.")
        except (KeyError, ValueError):
            return None

    @staticmethod
    def get_interface_mtu(node, iface_key):
        """Get interface MTU.

        Returns physical layer MTU (max. size of Ethernet frame).
        :param node: Node to get interface MTU on.
        :param iface_key: Interface key from topology file.
        :type node: dict
        :type iface_key: str
        :returns: MTU or None if not found.
        :rtype: int
        """
        try:
            return node['interfaces'][iface_key].get('mtu')
        except KeyError:
            return None

    @staticmethod
    def get_interface_name(node, iface_key):
        """Get interface name (retrieved from DUT/TG).

        Returns name in string format, retrieved from the node.
        :param node: Node to get interface name on.
        :param iface_key: Interface key from topology file.
        :type node: dict
        :type iface_key: str
        :returns: Interface name or None if not found.
        :rtype: str
        """
        try:
            return node['interfaces'][iface_key].get('name')
        except KeyError:
            return None

    @staticmethod
    def convert_interface_reference_to_key(node, interface):
        """Takes interface reference in any format
        (name, link name, interface key or sw_if_index)
        and converts to interface key using Topology methods.

        :param node: Node in topology.
        :param interface: Name, sw_if_index, link name or key of an interface
        on the node.
        Valid formats are: sw_if_index, key, name.
        :type node: dict
        :type interface: str or int

        :returns: Interface key.
        :rtype: str

        :raises TypeError: If provided with invalid interface argument.
        :raises RuntimeError: If the interface does not exist in topology.
        """

        if isinstance(interface, int):
            key = Topology.get_interface_by_sw_index(node, interface)
            if key is None:
                raise RuntimeError("Interface with sw_if_index={0} does not "
                                   "exist in topology.".format(interface))
        elif interface in Topology.get_node_interfaces(node):
            key = interface
        elif interface in Topology.get_links({"dut": node}):
            key = Topology.get_interface_by_link_name(node, interface)
        elif isinstance(interface, basestring):
            key = Topology.get_interface_by_name(node, interface)
            if key is None:
                raise RuntimeError("Interface with key, name or link name "
                                   "\"{0}\" does not exist in topology."
                                   .format(interface))
        else:
            raise TypeError("Type of interface argument must be integer"
                            " or string.")
        return key

    @staticmethod
    def convert_interface_reference(node, interface, wanted_format):
        """Takes interface reference in any format
        (name, link name, topology key or sw_if_index) and returns
        its equivalent in the desired format.

        :param node: Node in topology.
        :param interface: Name, sw_if_index, link name or key of an interface
        on the node.
        :param wanted_format: Format of return value wanted.
        Valid options are: sw_if_index, key, name.
        :type node: dict
        :type interface: str or int
        :type wanted_format: str

        :returns: Interface name, interface key or sw_if_index.
        :rtype: str or int

        :raises TypeError, ValueError: If provided with invalid arguments.
        :raises RuntimeError: If the interface does not exist in topology.
        """

        key = Topology.convert_interface_reference_to_key(node, interface)

        conversions = {
            "key": lambda x, y: y,
            "name": Topology.get_interface_name,
            "sw_if_index": Topology.get_interface_sw_index
        }

        try:
            return conversions[wanted_format](node, key)
        except KeyError:
            raise ValueError("Unrecognized return value wanted: {0}."
                             "Valid options are key, name, sw_if_index"
                             .format(wanted_format))

    @staticmethod
    def get_interface_numa_node(node, iface_key):
        """Get interface numa node.

        Returns physical relation to numa node, numa_id.

        :param node: Node to get numa id on.
        :param iface_key: Interface key from topology file.
        :type node: dict
        :type iface_key: str
        :returns: numa node id, None if not available.
        :rtype: int
        """
        try:
            return node['interfaces'][iface_key].get('numa_node')
        except KeyError:
            return None

    @staticmethod
    def get_interfaces_numa_node(node, *iface_keys):
        """Get numa node on which are located most of the interfaces.

        Return numa node with highest count of interfaces provided as arguments.
        Return 0 if the interface does not have numa_node information available.
        If all interfaces have unknown location (-1), then return 0.
        If most of interfaces have unknown location (-1), but there are
        some interfaces with known location, then return the second most
        location of the provided interfaces.

        :param node: Node from DICT__nodes.
        :param iface_keys: Interface keys for lookup.
        :type node: dict
        :type iface_keys: strings
        """
        numa_list = []
        for if_key in iface_keys:
            try:
                numa_list.append(node['interfaces'][if_key].get('numa_node'))
            except KeyError:
                pass

        numa_cnt_mc = Counter(numa_list).most_common()

        if len(numa_cnt_mc) > 0 and numa_cnt_mc[0][0] != -1:
            return numa_cnt_mc[0][0]
        elif len(numa_cnt_mc) > 1 and numa_cnt_mc[0][0] == -1:
            return numa_cnt_mc[1][0]
        else:
            return 0

    @staticmethod
    def get_interface_mac(node, iface_key):
        """Get MAC address for the interface.

        :param node: Node to get interface mac on.
        :param iface_key: Interface key from topology file.
        :type node: dict
        :type iface_key: str
        :returns: Return MAC or None if not found.
        """
        try:
            return node['interfaces'][iface_key].get('mac_address')
        except KeyError:
            return None

    @staticmethod
    def get_interface_ip4(node, iface_key):
        """Get IP4 address for the interface.

        :param node: Node to get interface mac on.
        :param iface_key: Interface key from topology file.
        :type node: dict
        :type iface_key: str
        :returns: Return IP4 or None if not found.
        """
        try:
            return node['interfaces'][iface_key].get('ip4_address', None)
        except KeyError:
            return None

    @staticmethod
    def get_adjacent_node_and_interface(nodes_info, node, iface_key):
        """Get node and interface adjacent to specified interface
        on local network.

        :param nodes_info: Dictionary containing information on all nodes
        in topology.
        :param node: Node that contains specified interface.
        :param iface_key: Interface key from topology file.
        :type nodes_info: dict
        :type node: dict
        :type iface_key: str
        :returns: Return (node, interface_key) tuple or None if not found.
        :rtype: (dict, str)
        """
        link_name = None
        # get link name where the interface belongs to
        for if_key, if_val in node['interfaces'].iteritems():
            if if_key == 'mgmt':
                continue
            if if_key == iface_key:
                link_name = if_val['link']
                break

        if link_name is None:
            return None

        # find link
        for node_data in nodes_info.values():
            # skip self
            if node_data['host'] == node['host']:
                continue
            for if_key, if_val \
                    in node_data['interfaces'].iteritems():
                if 'link' not in if_val:
                    continue
                if if_val['link'] == link_name:
                    return node_data, if_key

    @staticmethod
    def get_interface_pci_addr(node, iface_key):
        """Get interface PCI address.

        :param node: Node to get interface PCI address on.
        :param iface_key: Interface key from topology file.
        :type node: dict
        :type iface_key: str
        :returns: Return PCI address or None if not found.
        """
        try:
            return node['interfaces'][iface_key].get('pci_address')
        except KeyError:
            return None

    @staticmethod
    def get_interface_driver(node, iface_key):
        """Get interface driver.

        :param node: Node to get interface driver on.
        :param iface_key: Interface key from topology file.
        :type node: dict
        :type iface_key: str
        :returns: Return interface driver or None if not found.
        """
        try:
            return node['interfaces'][iface_key].get('driver')
        except KeyError:
            return None

    @staticmethod
    def get_node_interfaces(node):
        """Get all node interfaces.

        :param node: Node to get list of interfaces from.
        :type node: dict
        :returns: Return list of keys of all interfaces.
        :rtype: list
        """
        return node['interfaces'].keys()

    @staticmethod
    def get_node_link_mac(node, link_name):
        """Return interface mac address by link name.

        :param node: Node to get interface sw_index on.
        :param link_name: Link name.
        :type node: dict
        :type link_name: str
        :returns: MAC address string.
        :rtype: str
        """
        for port in node['interfaces'].values():
            if port.get('link') == link_name:
                return port.get('mac_address')
        return None

    @staticmethod
    def _get_node_active_link_names(node, filter_list=None):
        """Return list of link names that are other than mgmt links.

        :param node: Node topology dictionary.
        :param filter_list: Link filter criteria.
        :type node: dict
        :type filter_list: list of strings
        :returns: List of strings representing link names occupied by the node.
        :rtype: list
        """
        interfaces = node['interfaces']
        link_names = []
        for interface in interfaces.values():
            if 'link' in interface:
                if (filter_list is not None) and ('model' in interface):
                    for filt in filter_list:
                        if filt == interface['model']:
                            link_names.append(interface['link'])
                elif (filter_list is not None) and ('model' not in interface):
                    logger.trace('Cannot apply filter on interface: {}'
                                 .format(str(interface)))
                else:
                    link_names.append(interface['link'])
        if len(link_names) == 0:
            link_names = None
        return link_names

    @keyword('Get active links connecting "${node1}" and "${node2}"')
    def get_active_connecting_links(self, node1, node2,
                                    filter_list_node1=None,
                                    filter_list_node2=None):
        """Return list of link names that connect together node1 and node2.

        :param node1: Node topology dictionary.
        :param node2: Node topology dictionary.
        :param filter_list_node1: Link filter criteria for node1.
        :param filter_list_node2: Link filter criteria for node2.
        :type node1: dict
        :type node2: dict
        :type filter_list_node1: list of strings
        :type filter_list_node2: list of strings
        :returns: List of strings that represent connecting link names.
        :rtype: list
        """

        logger.trace("node1: {}".format(str(node1)))
        logger.trace("node2: {}".format(str(node2)))
        node1_links = self._get_node_active_link_names(
            node1,
            filter_list=filter_list_node1)
        node2_links = self._get_node_active_link_names(
            node2,
            filter_list=filter_list_node2)

        connecting_links = None
        if node1_links is None:
            logger.error("Unable to find active links for node1")
        elif node2_links is None:
            logger.error("Unable to find active links for node2")
        else:
            connecting_links = list(set(node1_links).intersection(node2_links))

        return connecting_links

    @keyword('Get first active connecting link between node "${node1}" and '
             '"${node2}"')
    def get_first_active_connecting_link(self, node1, node2):
        """

        :param node1: Connected node.
        :param node2: Connected node.
        :type node1: dict
        :type node2: dict
        :returns: Name of link connecting the two nodes together.
        :rtype: str
        :raises: RuntimeError
        """
        connecting_links = self.get_active_connecting_links(node1, node2)
        if len(connecting_links) == 0:
            raise RuntimeError("No links connecting the nodes were found")
        else:
            return connecting_links[0]

    @keyword('Get egress interfaces name on "${node1}" for link with '
             '"${node2}"')
    def get_egress_interfaces_name_for_nodes(self, node1, node2):
        """Get egress interfaces on node1 for link with node2.

        :param node1: First node, node to get egress interface on.
        :param node2: Second node.
        :type node1: dict
        :type node2: dict
        :returns: Egress interfaces.
        :rtype: list
        """
        interfaces = []
        links = self.get_active_connecting_links(node1, node2)
        if len(links) == 0:
            raise RuntimeError('No link between nodes')
        for interface in node1['interfaces'].values():
            link = interface.get('link')
            if link is None:
                continue
            if link in links:
                continue
            name = interface.get('name')
            if name is None:
                continue
            interfaces.append(name)
        return interfaces

    @keyword('Get first egress interface name on "${node1}" for link with '
             '"${node2}"')
    def get_first_egress_interface_for_nodes(self, node1, node2):
        """Get first egress interface on node1 for link with node2.

        :param node1: First node, node to get egress interface name on.
        :param node2: Second node.
        :type node1: dict
        :type node2: dict
        :returns: Egress interface name.
        :rtype: str
        """
        interfaces = self.get_egress_interfaces_name_for_nodes(node1, node2)
        if not interfaces:
            raise RuntimeError('No egress interface for nodes')
        return interfaces[0]

    @keyword('Get link data useful in circular topology test from tg "${tgen}"'
             ' dut1 "${dut1}" dut2 "${dut2}"')
    def get_links_dict_from_nodes(self, tgen, dut1, dut2):
        """Return link combinations used in tests in circular topology.

        For the time being it returns links from the Node path:
        TG->DUT1->DUT2->TG
        The naming convention until changed to something more general is
        implemented is this:
        DUT1_DUT2_LINK: link name between DUT! and DUT2
        DUT1_TG_LINK: link name between DUT1 and TG
        DUT2_TG_LINK: link name between DUT2 and TG
        TG_TRAFFIC_LINKS: list of link names that generated traffic is sent
        to and from
        DUT1_BD_LINKS: list of link names that will be connected by the bridge
        domain on DUT1
        DUT2_BD_LINKS: list of link names that will be connected by the bridge
        domain on DUT2

        :param tgen: Traffic generator node data.
        :param dut1: DUT1 node data.
        :param dut2: DUT2 node data.
        :type tgen: dict
        :type dut1: dict
        :type dut2: dict
        :returns: Dictionary of possible link combinations.
        :rtype: dict
        """
        # TODO: replace with generic function.
        dut1_dut2_link = self.get_first_active_connecting_link(dut1, dut2)
        dut1_tg_link = self.get_first_active_connecting_link(dut1, tgen)
        dut2_tg_link = self.get_first_active_connecting_link(dut2, tgen)
        tg_traffic_links = [dut1_tg_link, dut2_tg_link]
        dut1_bd_links = [dut1_dut2_link, dut1_tg_link]
        dut2_bd_links = [dut1_dut2_link, dut2_tg_link]
        topology_links = {'DUT1_DUT2_LINK': dut1_dut2_link,
                          'DUT1_TG_LINK': dut1_tg_link,
                          'DUT2_TG_LINK': dut2_tg_link,
                          'TG_TRAFFIC_LINKS': tg_traffic_links,
                          'DUT1_BD_LINKS': dut1_bd_links,
                          'DUT2_BD_LINKS': dut2_bd_links}
        return topology_links

    @staticmethod
    def is_tg_node(node):
        """Find out whether the node is TG.

        :param node: Node to examine.
        :type node: dict
        :returns: True if node is type of TG, otherwise False.
        :rtype: bool
        """
        return node['type'] == NodeType.TG

    @staticmethod
    def get_node_hostname(node):
        """Return host (hostname/ip address) of the node.

        :param node: Node created from topology.
        :type node: dict
        :returns: Hostname or IP address.
        :rtype: str
        """
        return node['host']

    @staticmethod
    def get_cryptodev(node):
        """Return Crytodev configuration of the node.

        :param node: Node created from topology.
        :type node: dict
        :returns: Cryptodev configuration string.
        :rtype: str
        """
        try:
            return node['cryptodev']
        except KeyError:
            return None

    @staticmethod
    def get_uio_driver(node):
        """Return uio-driver configuration of the node.

        :param node: Node created from topology.
        :type node: dict
        :returns: uio-driver configuration string.
        :rtype: str
        """
        try:
            return node['uio_driver']
        except KeyError:
            return None

    @staticmethod
    def set_interface_numa_node(node, iface_key, numa_node_id):
        """Set interface numa_node location.

        :param node: Node to set numa_node on.
        :param iface_key: Interface key from topology file.
        :type node: dict
        :type iface_key: str
        :returns: Return iface_key or None if not found.
        """
        try:
            node['interfaces'][iface_key]['numa_node'] = numa_node_id
            return iface_key
        except KeyError:
            return None