Commit eecdda0354 for frr

commit eecdda0354a2c97ebb9152b20ce096b2e8dec9a0
Author: Minghan Chan <mhchann082@gmail.com>
Date:   Fri Nov 6 08:24:17 2026 +0800

    tests: check sbfd reflector discriminator ranges and limits

    Add a step to sbfd_topo1 that adds and deletes a reflector range that
    ends at 4294967295, which kept bfdd from answering, checks that illegal
    discriminators and too many of them are rejected without adding any
    reflector, and adds and deletes the largest range one command allows.

    Each vtysh call runs under timeout(1). When bfdd does not answer, the
    step kills it and fails: the vtysh calls that topotest makes after the
    test have no time limit, so a stuck bfdd would hang the whole run.

    Signed-off-by: Minghan Chan <mhchann082@gmail.com>

diff --git a/tests/topotests/sbfd_topo1/test_sbfd_topo1.py b/tests/topotests/sbfd_topo1/test_sbfd_topo1.py
index 311ed66097..8222b1f467 100644
--- a/tests/topotests/sbfd_topo1/test_sbfd_topo1.py
+++ b/tests/topotests/sbfd_topo1/test_sbfd_topo1.py
@@ -43,7 +43,7 @@ sys.path.append(os.path.join(CWD, "../"))
 from lib import topotest
 from lib.topogen import Topogen, get_topogen
 from lib.topolog import logger
-from lib.common_config import required_linux_kernel_version
+from lib.common_config import required_linux_kernel_version, step
 from lib.checkping import check_ping

 """
@@ -284,6 +284,101 @@ def test_sbfd_echo_returned_with_hop_limit_255():
     )


+# A command that never returns would hang vtysh, and the test, forever.
+VTYSH_TIMEOUT = 15
+
+
+def bfdd_vtysh(router, *commands):
+    "Run commands in one vtysh call with a time limit. Return its exit code and output."
+    output = router.cmd(
+        "timeout {} vtysh {}; echo rc=$?".format(
+            VTYSH_TIMEOUT, " ".join("-c '{}'".format(c) for c in commands)
+        )
+    )
+    output, _, rc = output.rstrip().rpartition("rc=")
+    rc = int(rc)
+    if rc == 124:
+        # Kill the stuck bfdd. The vtysh calls that topotest makes after the
+        # test have no time limit and would wait for it forever.
+        router.cmd("kill -KILL $(cat /var/run/frr/bfdd.pid)")
+    assert rc != 124, "bfdd did not answer '{}' in {} seconds".format(
+        commands[-1], VTYSH_TIMEOUT
+    )
+    return rc, output
+
+
+def sbfd_reflector_config(router, command):
+    "Run command in the bfd node. Return vtysh's exit code and output."
+    return bfdd_vtysh(router, "configure terminal", "bfd", command)
+
+
+def sbfd_reflector_discrs(router):
+    "Return the set of reflector discriminators in 'show sbfd reflector'."
+    _, output = bfdd_vtysh(router, "show sbfd reflector")
+    discrs = set()
+    for line in output.splitlines():
+        fields = line.split()
+        if fields and fields[0].isdigit():
+            discrs.add(int(fields[0]))
+    return discrs
+
+
+# step 5: discriminator ranges and limits
+def test_sbfd_reflector_discriminator_range():
+    "Assert that discriminator ranges up to 4294967295 add and delete what they cover."
+    tgen = get_topogen()
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r2 = tgen.net["r2"]
+    before = sbfd_reflector_discrs(r2)
+    top = {4294967293, 4294967294, 4294967295}
+
+    step("Add a range that ends at 4294967295")
+    rc, output = sbfd_reflector_config(
+        r2, "sbfd reflector source-address 2001::20 discriminator 4294967293-4294967295"
+    )
+    assert rc == 0, "range 4294967293-4294967295 rejected: {}".format(output)
+    assert sbfd_reflector_discrs(r2) == before | top
+
+    step("Reject illegal discriminators without adding any reflector")
+    for discr, error in [
+        ("4294967295-4294967295", "is illegal"),
+        ("200-100", "is illegal"),
+        ("0", "is illegal"),
+        ("4294967296", "is illegal"),
+        ("100-102 -50", "is illegal"),
+        ("7 abc", "is illegal"),
+        ("1-65536 4294967290", "Too many discriminators (65537)"),
+    ]:
+        rc, output = sbfd_reflector_config(
+            r2, "sbfd reflector source-address 2001::20 discriminator " + discr
+        )
+        assert rc != 0, "discriminator {} accepted".format(discr)
+        assert error in output, "discriminator {}: expected '{}' in: {}".format(
+            discr, error, output
+        )
+        assert sbfd_reflector_discrs(r2) == before | top, "discriminator {}".format(
+            discr
+        )
+
+    step("Add and delete the largest range one command allows")
+    many = set(range(1000001, 1065537))
+    rc, output = sbfd_reflector_config(
+        r2, "sbfd reflector source-address 2001::20 discriminator 1000001-1065536"
+    )
+    assert rc == 0, "range 1000001-1065536 rejected: {}".format(output)
+    assert sbfd_reflector_discrs(r2) == before | top | many
+    rc, output = sbfd_reflector_config(r2, "no sbfd reflector 1000001 1065536")
+    assert rc == 0, "no sbfd reflector 1000001 1065536 failed: {}".format(output)
+    assert sbfd_reflector_discrs(r2) == before | top
+
+    step("Delete a range that ends at 4294967295")
+    rc, output = sbfd_reflector_config(r2, "no sbfd reflector 4294967293 4294967295")
+    assert rc == 0, "no sbfd reflector 4294967293 4294967295 failed: {}".format(output)
+    assert sbfd_reflector_discrs(r2) == before
+
+
 # Memory leak test template
 def test_memory_leak():
     "Run the memory leak test and report results."