tests: Check if disable-addpath-rx knob works

Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>

tests/topotests/bgp_disable_addpath_rx/r1/bgpd.conf

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+!
+router bgp 65001
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.2 remote-as external
+ address-family ipv4 unicast
+  neighbor 192.168.1.2 disable-addpath-rx
+ exit-address-family
+!

tests/topotests/bgp_disable_addpath_rx/r1/zebra.conf

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

tests/topotests/bgp_disable_addpath_rx/r2/bgpd.conf

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+router bgp 65002
+ no bgp ebgp-requires-policy
+ neighbor 192.168.1.1 remote-as external
+ neighbor 192.168.2.3 remote-as external
+ neighbor 192.168.2.4 remote-as external
+ address-family ipv4 unicast
+  neighbor 192.168.1.1 addpath-tx-all-paths
+ exit-address-family
+!

tests/topotests/bgp_disable_addpath_rx/r2/zebra.conf

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+!
+int r2-eth0
+ ip address 192.168.1.2/24
+!
+int r2-eth1
+ ip address 192.168.2.2/24
+!

tests/topotests/bgp_disable_addpath_rx/r3/bgpd.conf

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+router bgp 65003
+ no bgp ebgp-requires-policy
+ neighbor 192.168.2.2 remote-as external
+ address-family ipv4 unicast
+  redistribute connected
+ exit-address-family
+!

tests/topotests/bgp_disable_addpath_rx/r3/zebra.conf

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+!
+int lo
+ ip address 172.16.16.254/32
+!
+int r3-eth0
+ ip address 192.168.2.3/24
+!

tests/topotests/bgp_disable_addpath_rx/r4/bgpd.conf

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+router bgp 65004
+ no bgp ebgp-requires-policy
+ neighbor 192.168.2.2 remote-as external
+ address-family ipv4 unicast
+  redistribute connected
+ exit-address-family
+!

tests/topotests/bgp_disable_addpath_rx/r4/zebra.conf

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+!
+int lo
+ ip address 172.16.16.254/32
+!
+int r4-eth0
+ ip address 192.168.2.4/24
+!

tests/topotests/bgp_disable_addpath_rx/test_disable_addpath_rx.py

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+#!/usr/bin/env python
+
+# Copyright (c) 2021 by
+# Donatas Abraitis <donatas.abraitis@gmail.com>
+#
+# Permission to use, copy, modify, and/or distribute this software
+# for any purpose with or without fee is hereby granted, provided
+# that the above copyright notice and this permission notice appear
+# in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND NETDEF DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NETDEF BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY
+# DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+# WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+# OF THIS SOFTWARE.
+#
+
+"""
+Test if AddPath RX direction is not negotiated via AddPath capability.
+"""
+
+import os
+import sys
+import json
+import time
+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
+from lib.topolog import logger
+from mininet.topo import Topo
+from lib.common_config import step
+
+pytestmark = [pytest.mark.bgpd]
+
+
+class TemplateTopo(Topo):
+    def build(self, *_args, **_opts):
+        tgen = get_topogen(self)
+
+        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 = tgen.add_switch("s2")
+        switch.add_link(tgen.gears["r2"])
+        switch.add_link(tgen.gears["r3"])
+        switch.add_link(tgen.gears["r4"])
+
+
+def setup_module(mod):
+    tgen = Topogen(TemplateTopo, 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_disable_addpath_rx():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r1 = tgen.gears["r1"]
+    r2 = tgen.gears["r2"]
+
+    step(
+        "Check if r2 advertised only 2 paths to r1 (despite addpath-tx-all-paths enabled on r2)."
+    )
+
+    def check_bgp_advertised_routes(router):
+        output = json.loads(
+            router.vtysh_cmd(
+                "show bgp ipv4 unicast neighbor 192.168.1.1 advertised-routes json"
+            )
+        )
+        expected = {
+            "advertisedRoutes": {
+                "172.16.16.254/32": {
+                    "addrPrefix": "172.16.16.254",
+                    "prefixLen": 32,
+                },
+                "192.168.2.0/24": {
+                    "addrPrefix": "192.168.2.0",
+                    "prefixLen": 24,
+                },
+            },
+            "totalPrefixCounter": 2,
+        }
+
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(check_bgp_advertised_routes, r2)
+    success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
+    assert result is None, "AddPath TX not working."
+
+    step("Check if AddPath RX is disabled on r1 and we receive only 2 paths.")
+
+    def check_bgp_disabled_addpath_rx(router):
+        output = json.loads(router.vtysh_cmd("show bgp neighbor 192.168.1.2 json"))
+        expected = {
+            "192.168.1.2": {
+                "bgpState": "Established",
+                "neighborCapabilities": {
+                    "addPath": {
+                        "ipv4Unicast": {"txReceived": True, "rxReceived": True}
+                    },
+                },
+                "addressFamilyInfo": {"ipv4Unicast": {"acceptedPrefixCounter": 2}},
+            }
+        }
+
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(check_bgp_disabled_addpath_rx, r1)
+    success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
+    assert result is None, "AddPath RX advertised, but should not."
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))