[PATCH net-next v3 5/5] selftests: drv-net-hw: Add a test for symmetric RSS hash

[Gal Pressman <gal@nvidia.com>]

Add a selftest that verifies symmetric RSS hash is working as intended.
The test runs two iterations of iperf3 traffic, swapping the src/dst TCP
ports, and verifies that the same RX queue is receiving the traffic in
both cases.

Reviewed-by: Nimrod Oren <noren@nvidia.com>
Signed-off-by: Gal Pressman <gal@nvidia.com>
---
 .../testing/selftests/drivers/net/hw/Makefile |  1 +
 .../drivers/net/hw/rss_input_xfrm.py          | 77 +++++++++++++++++++
 .../selftests/drivers/net/lib/py/load.py      |  7 +-
 3 files changed, 83 insertions(+), 2 deletions(-)
 create mode 100755 tools/testing/selftests/drivers/net/hw/rss_input_xfrm.py

diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
index 21ba64ce1e34..23dca086f84f 100644
--- a/tools/testing/selftests/drivers/net/hw/Makefile
+++ b/tools/testing/selftests/drivers/net/hw/Makefile
@@ -15,6 +15,7 @@ TEST_PROGS = \
 	nic_performance.py \
 	pp_alloc_fail.py \
 	rss_ctx.py \
+	rss_input_xfrm.py \
 	#
 
 TEST_FILES := \
diff --git a/tools/testing/selftests/drivers/net/hw/rss_input_xfrm.py b/tools/testing/selftests/drivers/net/hw/rss_input_xfrm.py
new file mode 100755
index 000000000000..e32df852f091
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/rss_input_xfrm.py
@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_pr
+from lib.py import NetDrvEpEnv
+from lib.py import EthtoolFamily, NetdevFamily
+from lib.py import KsftSkipEx
+from lib.py import rand_port, check_port_available_remote
+from lib.py import GenerateTraffic
+from rss_ctx import _get_rx_cnts
+
+
+def _get_active_rx_queue(cnts):
+    return cnts.index(max(cnts))
+
+
+def _get_rand_port(remote):
+    for _ in range(1000):
+        port = rand_port()
+        try:
+            check_port_available_remote(port, remote)
+            return port
+        except:
+            continue
+
+    raise Exception("Can't find any free unprivileged port")
+
+
+def test_rss_input_xfrm(cfg):
+    """
+    Test symmetric input_xfrm.
+    If symmetric RSS hash is configured, send traffic twice, swapping the
+    src/dst TCP ports, and verify that the same queue is receiving the traffic
+    in both cases (IPs are constant).
+    """
+
+    input_xfrm = cfg.ethnl.rss_get(
+        {'header': {'dev-name': cfg.ifname}}).get('input_xfrm')
+
+    # Check for symmetric xor/or-xor
+    if input_xfrm and (input_xfrm == 1 or input_xfrm == 2):
+        port1 = _get_rand_port(cfg.remote)
+        port2 = _get_rand_port(cfg.remote)
+        ksft_pr(f'Running traffic on ports: {port1 = }, {port2 = }')
+
+        cnts = _get_rx_cnts(cfg)
+        GenerateTraffic(cfg, port=port1, parallel=1,
+                        cport=port2).wait_pkts_and_stop(20000)
+        cnts = _get_rx_cnts(cfg, prev=cnts)
+        rxq1 = _get_active_rx_queue(cnts)
+        ksft_pr(f'Received traffic on {rxq1 = }')
+
+        cnts = _get_rx_cnts(cfg)
+        GenerateTraffic(cfg, port=port2, parallel=1,
+                        cport=port1).wait_pkts_and_stop(20000)
+        cnts = _get_rx_cnts(cfg, prev=cnts)
+        rxq2 = _get_active_rx_queue(cnts)
+        ksft_pr(f'Received traffic on {rxq2 = }')
+
+        ksft_eq(
+            rxq1, rxq2, comment=f"Received traffic on different queues ({rxq1} != {rxq2}) while symmetric hash is configured")
+    else:
+        raise KsftSkipEx("Symmetric RSS hash not requested")
+
+
+def main() -> None:
+    with NetDrvEpEnv(__file__, nsim_test=False) as cfg:
+        cfg.ethnl = EthtoolFamily()
+        cfg.netdevnl = NetdevFamily()
+
+        ksft_run([test_rss_input_xfrm],
+                 args=(cfg, ))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tools/testing/selftests/drivers/net/lib/py/load.py b/tools/testing/selftests/drivers/net/lib/py/load.py
index da5af2c680fa..76aaa65c0367 100644
--- a/tools/testing/selftests/drivers/net/lib/py/load.py
+++ b/tools/testing/selftests/drivers/net/lib/py/load.py
@@ -5,7 +5,7 @@ import time
 from lib.py import ksft_pr, cmd, ip, rand_port, wait_port_listen, bkg
 
 class GenerateTraffic:
-    def __init__(self, env, port=None):
+    def __init__(self, env, port=None, cport=None, parallel=16):
         env.require_cmd("iperf3", remote=True)
 
         self.env = env
@@ -15,7 +15,10 @@ class GenerateTraffic:
         self._iperf_server = cmd(f"iperf3 -s -1 -p {port}", background=True)
         wait_port_listen(port)
         time.sleep(0.1)
-        self._iperf_client = cmd(f"iperf3 -c {env.addr} -P 16 -p {port} -t 86400",
+        client_cmd = f"iperf3 -c {env.addr} -P {parallel} -p {port} -t 86400"
+        if cport and parallel == 1:
+            client_cmd = f"{client_cmd} --cport {cport}"
+        self._iperf_client = cmd(client_cmd,
                                  background=True, host=env.remote)
 
         # Wait for traffic to ramp up
-- 
2.40.1