tests: Check if BGP confederation works with AS_EXTERNAL (!AS_SPECIFIED)

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
(cherry picked from commit caf65e4a27)

tests/topotests/bgp_confederation_astype/r1/bgpd.conf

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+router bgp 65001
+ no bgp ebgp-requires-policy
+ bgp confederation identifier 65300
+ bgp confederation peers 65002 65003
+ neighbor fabric peer-group
+ neighbor fabric remote-as external
+ neighbor 192.168.1.2 peer-group fabric
+ neighbor 192.168.2.2 remote-as external
+ address-family ipv4 unicast
+  neighbor fabric activate
+ exit-address-family
+!

tests/topotests/bgp_confederation_astype/r1/zebra.conf

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+!
+int r1-eth0
+ ip address 192.168.1.1/24
+!
+int r1-eth1
+ ip address 192.168.2.1/24
+!

tests/topotests/bgp_confederation_astype/r2/bgpd.conf

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+router bgp 65002
+ no bgp ebgp-requires-policy
+ no bgp network import-check
+ bgp confederation identifier 65300
+ bgp confederation peers 65001
+ neighbor fabric peer-group
+ neighbor fabric remote-as external
+ neighbor 192.168.1.1 peer-group fabric
+ address-family ipv4 unicast
+  network 172.16.255.254/32
+  neighbor fabric activate
+ exit-address-family
+!

tests/topotests/bgp_confederation_astype/r2/zebra.conf

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+!
+int r2-eth0
+ ip address 192.168.1.2/24
+!

tests/topotests/bgp_confederation_astype/r3/bgpd.conf

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+router bgp 65003
+ no bgp ebgp-requires-policy
+ no bgp network import-check
+ bgp confederation identifier 65300
+ bgp confederation peers 65001
+ neighbor 192.168.2.1 remote-as external
+ address-family ipv4 unicast
+  network 172.16.255.254/32
+ exit-address-family
+!

tests/topotests/bgp_confederation_astype/r3/zebra.conf

@@ -0,0 +1,4 @@
+!
+int r3-eth0
+ ip address 192.168.2.2/24
+!

tests/topotests/bgp_confederation_astype/test_bgp_confederation_astype.py

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+#!/usr/bin/env python
+# SPDX-License-Identifier: ISC
+
+# Copyright (c) 2022 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+
+"""
+Test if BGP confederation works properly when using
+remote-as internal/external.
+
+Also, check if the same works with peer-groups as well.
+"""
+
+import os
+import sys
+import json
+import pytest
+import functools
+
+pytestmark = pytest.mark.bgpd
+
+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 setup_module(mod):
+    topodef = {"s1": ("r1", "r2"), "s2": ("r1", "r3")}
+    tgen = Topogen(topodef, mod.__name__)
+    tgen.start_topology()
+
+    router_list = tgen.routers()
+
+    for i, (rname, router) in enumerate(router_list.items(), 1):
+        router.load_config(
+            TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
+        )
+        router.load_config(
+            TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
+        )
+
+    tgen.start_router()
+
+
+def teardown_module(mod):
+    tgen = get_topogen()
+    tgen.stop_topology()
+
+
+def test_bgp_confederation_astype():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r1 = tgen.gears["r1"]
+
+    def _bgp_converge():
+        output = json.loads(r1.vtysh_cmd("show bgp summary json"))
+        expected = {
+            "ipv4Unicast": {
+                "peerCount": 2,
+                "peers": {
+                    "192.168.1.2": {
+                        "hostname": "r2",
+                        "remoteAs": 65002,
+                        "localAs": 65001,
+                        "pfxRcd": 1,
+                        "state": "Established",
+                    },
+                    "192.168.2.2": {
+                        "hostname": "r3",
+                        "remoteAs": 65003,
+                        "localAs": 65001,
+                        "pfxRcd": 1,
+                        "state": "Established",
+                    },
+                },
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(_bgp_converge)
+    _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
+    assert result is None, "Can't converge"
+
+    def _bgp_check_neighbors():
+        output = json.loads(r1.vtysh_cmd("show bgp neighbors json"))
+        expected = {
+            "192.168.1.2": {
+                "nbrCommonAdmin": True,
+                "nbrConfedExternalLink": True,
+                "hostname": "r2",
+            },
+            "192.168.2.2": {
+                "nbrCommonAdmin": True,
+                "nbrConfedExternalLink": True,
+                "hostname": "r3",
+            },
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(_bgp_check_neighbors)
+    _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
+    assert result is None, "Can't see neighbors to be in BGP confederation"
+
+    def _bgp_check_routes():
+        output = json.loads(r1.vtysh_cmd("show bgp ipv4 unicast json"))
+        expected = {
+            "routes": {
+                "172.16.255.254/32": [
+                    {
+                        "valid": True,
+                        "pathFrom": "external",
+                        "path": "(65003)",
+                    },
+                    {
+                        "valid": True,
+                        "pathFrom": "external",
+                        "path": "(65002)",
+                    },
+                ]
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(_bgp_check_routes)
+    _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
+    assert result is None, "Can't see routes to be in BGP confederation"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))