tests: traffic control PoC topotests

This commit adds a basic test for sharpd traffic control PoC, which will check
interface TC info from iproute2 `tc` cli.

Signed-off-by: Siger Yang <siger.yang@outlook.com>

diff --git a/tests/topotests/tc_basic/test_tc_basic.py b/tests/topotests/tc_basic/test_tc_basic.py
new file mode 100755 (executable)
index 0000000..e98e11d
--- /dev/null
+++ b/tests/topotests/tc_basic/test_tc_basic.py
@@ -0,0 +1,133 @@
+#!/usr/bin/python
+
+#
+# test_tc_basic.py
+#
+# Copyright (c) 2022 by Shichu Yang
+#
+# 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_tc_basic.py: Test basic TC filters, classes and qdiscs.
+"""
+import sys
+import os
+import pytest
+import time
+
+# Save the Current Working Directory to find configuration files.
+CWD = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(CWD, "../"))
+sys.path.append(os.path.join(CWD, "../lib/"))
+
+from lib.topogen import Topogen, TopoRouter
+from lib.topolog import logger
+
+pytestmark = [
+    pytest.mark.sharpd
+]
+
+def build_topo(tgen):
+    "Build function"
+
+    r1 = tgen.add_router("r1")
+    r2 = tgen.add_router("r2")
+
+    # Create a p2p connection between r1 and r2
+    tgen.add_link(r1, r2)
+
+    # Create switches with each router connected to it to simulate a empty network.
+    switch = tgen.add_switch("s1")
+    switch.add_link(r1)
+
+    switch = tgen.add_switch("s2")
+    switch.add_link(r2)
+
+# New form of setup/teardown using pytest fixture
+@pytest.fixture(scope="module")
+def tgen(request):
+    "Setup/Teardown the environment and provide tgen argument to tests"
+
+    # This function initiates the topology build with Topogen...
+    tgen = Topogen(build_topo, request.module.__name__)
+
+    # ... and here it calls initialization functions.
+    tgen.start_topology()
+
+    # This is a sample of configuration loading.
+    router_list = tgen.routers()
+
+    # For all routers arrange for:
+    # - starting zebra using config file from <rtrname>/zebra.conf
+    # - starting ospfd using an empty config file.
+    for _, router in router_list.items():
+        router.load_config(TopoRouter.RD_ZEBRA)
+        router.load_config(TopoRouter.RD_SHARP)
+
+    # Start and configure the router daemons
+    tgen.start_router()
+
+    # Provide tgen as argument to each test function
+    yield tgen
+
+    # Teardown after last test runs
+    tgen.stop_topology()
+
+
+# Fixture that executes before each test
+@pytest.fixture(autouse=True)
+def skip_on_failure(tgen):
+    if tgen.routers_have_failure():
+        pytest.skip("skipped because of previous test failure")
+
+def fetch_iproute2_tc_info(r, interface):
+    qdisc = r.cmd("tc qdisc show dev %s" % interface)
+    tclass = r.cmd("tc class show dev %s" % interface)
+    tfilter = r.cmd("tc filter show dev %s" % interface)
+    return qdisc, tclass, tfilter
+
+# ===================
+# The tests functions
+# ===================
+
+def test_tc_basic(tgen):
+    "Test installing one pair of filter & class by sharpd"
+
+    r1 = tgen.gears["r1"]
+    intf = "r1-eth0"
+    r1.vtysh_cmd("sharp tc dev %s source 192.168.100.0/24 destination 192.168.101.0/24 ip-protocol tcp src-port 8000 dst-port 8001 rate 20mbit" % intf)
+
+    time.sleep(3)
+
+    qdisc, tclass, tfilter = fetch_iproute2_tc_info(r1, intf)
+
+    logger.info("tc qdisc on %s: %s", intf, qdisc)
+    logger.info("tc class on %s: %s", intf, tclass)
+    logger.info("tc filter on %s: %s", intf, tfilter)
+
+    assert "htb" in qdisc
+    assert "beef:" in qdisc
+
+    assert "20Mbit" in tclass
+
+    assert "tcp" in tfilter
+    assert "dst_ip 192.168.101.0/24" in tfilter
+    assert "src_ip 192.168.100.0/24" in tfilter
+    assert "dst_port 8001" in tfilter
+    assert "src_port 8000" in tfilter
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))
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