tests: Check if Node Target Extended Communities work

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

tests/topotests/bgp_node_target_extcommunities/r1/frr.conf

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+!
+int r1-eth0
+ ip address 192.168.1.1/24
+!
+router bgp 65001
+ bgp router-id 192.168.1.1
+ no bgp ebgp-requires-policy
+ no bgp network import-check
+ neighbor 192.168.1.2 remote-as external
+ neighbor 192.168.1.3 remote-as external
+ neighbor 192.168.1.4 remote-as external
+ address-family ipv4 unicast
+  network 10.10.10.10/32
+  neighbor 192.168.1.2 route-map rmap out
+  neighbor 192.168.1.3 route-map rmap out
+  neighbor 192.168.1.4 route-map rmap out
+ exit-address-family
+!
+route-map rmap permit 10
+ set extcommunity nt 192.168.1.3:0 192.168.1.4:0
+exit

tests/topotests/bgp_node_target_extcommunities/r2/frr.conf

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+!
+int r2-eth0
+ ip address 192.168.1.2/24
+!
+router bgp 65002
+ bgp router-id 192.168.1.2
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.1 remote-as external

tests/topotests/bgp_node_target_extcommunities/r3/frr.conf

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+!
+int r3-eth0
+ ip address 192.168.1.3/24
+!
+router bgp 65003
+ bgp router-id 192.168.1.3
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.1 remote-as external

tests/topotests/bgp_node_target_extcommunities/r4/frr.conf

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+!
+int r4-eth0
+ ip address 192.168.1.4/24
+!
+router bgp 65004
+ bgp router-id 192.168.1.4
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.1 remote-as external

tests/topotests/bgp_node_target_extcommunities/test_bgp_node_target_extcommunities.py

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+#!/usr/bin/env python
+# SPDX-License-Identifier: ISC
+
+# Copyright (c) 2023 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+
+"""
+Test if Node Target Extended Communities works.
+
+At r1 we set NT to 192.168.1.3 and 192.168.1.4 (this is the R3/R4 router-id),
+and that means 10.10.10.10/32 MUST be installed on R3 and R4, but not on R2,
+because this route does not have NT:192.168.1.2.
+"""
+
+import os
+import sys
+import json
+import pytest
+import functools
+
+CWD = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(CWD, "../"))
+
+# pylint: disable=C0413
+from lib import topotest
+from lib.topogen import Topogen, TopoRouter, get_topogen
+
+pytestmark = [pytest.mark.bgpd]
+
+
+def build_topo(tgen):
+    for routern in range(1, 5):
+        tgen.add_router("r{}".format(routern))
+
+    switch = tgen.add_switch("s1")
+    switch.add_link(tgen.gears["r1"])
+    switch.add_link(tgen.gears["r2"])
+    switch.add_link(tgen.gears["r3"])
+    switch.add_link(tgen.gears["r4"])
+
+
+def setup_module(mod):
+    tgen = Topogen(build_topo, mod.__name__)
+    tgen.start_topology()
+
+    router_list = tgen.routers()
+
+    for i, (rname, router) in enumerate(router_list.items(), 1):
+        router.load_frr_config(os.path.join(CWD, "{}/frr.conf".format(rname)))
+
+    tgen.start_router()
+
+
+def teardown_module(mod):
+    tgen = get_topogen()
+    tgen.stop_topology()
+
+
+def test_bgp_node_target_extended_communities():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r1 = tgen.gears["r1"]
+    r2 = tgen.gears["r2"]
+    r3 = tgen.gears["r3"]
+    r4 = tgen.gears["r4"]
+
+    def _bgp_converge():
+        output = json.loads(r1.vtysh_cmd("show bgp summary json"))
+        expected = {
+            "ipv4Unicast": {
+                "peers": {
+                    "192.168.1.2": {
+                        "pfxSnt": 1,
+                        "state": "Established",
+                    },
+                    "192.168.1.3": {
+                        "pfxSnt": 1,
+                        "state": "Established",
+                    },
+                    "192.168.1.4": {
+                        "pfxSnt": 1,
+                        "state": "Established",
+                    },
+                }
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(_bgp_converge)
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "Failed announcing 10.10.10.10/32 to r2, r3, and r4"
+
+    def _bgp_check_route(router, exists):
+        output = json.loads(router.vtysh_cmd("show bgp ipv4 unicast json"))
+        if exists:
+            expected = {
+                "routes": {
+                    "10.10.10.10/32": [
+                        {
+                            "valid": True,
+                        }
+                    ]
+                }
+            }
+        else:
+            expected = {
+                "routes": {
+                    "10.10.10.10/32": None,
+                }
+            }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(_bgp_check_route, r3, True)
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "10.10.10.10/32 is not installed, but SHOULD be"
+
+    test_func = functools.partial(_bgp_check_route, r4, True)
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "10.10.10.10/32 is not installed, but SHOULD be"
+
+    test_func = functools.partial(_bgp_check_route, r2, False)
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "10.10.10.10/32 is installed, but SHOULD NOT be"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))