* [PATCH net-next v4 4/4] selftests: drv-net: add test for RSS on flow label
[not found] <20250811234212.580748-1-kuba@kernel.org>
@ 2025-08-11 23:42 ` Jakub Kicinski
2025-08-12 0:37 ` Joe Damato
0 siblings, 1 reply; 2+ messages in thread
From: Jakub Kicinski @ 2025-08-11 23:42 UTC (permalink / raw)
To: davem
Cc: netdev, edumazet, pabeni, andrew+netdev, horms, donald.hunter,
michael.chan, pavan.chebbi, willemdebruijn.kernel, ecree.xilinx,
Jakub Kicinski, Willem de Bruijn, shuah, sdf, linux-kselftest
Add a simple test for checking that RSS on flow label works,
and that its rejected for IPv4 flows.
# ./tools/testing/selftests/drivers/net/hw/rss_flow_label.py
TAP version 13
1..2
ok 1 rss_flow_label.test_rss_flow_label
ok 2 rss_flow_label.test_rss_flow_label_6only
# Totals: pass:2 fail:0 xfail:0 xpass:0 skip:0 error:0
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
v2:
- check for RPS / RFS
v1: https://lore.kernel.org/20250722014915.3365370-5-kuba@kernel.org
CC: shuah@kernel.org
CC: sdf@fomichev.me
CC: linux-kselftest@vger.kernel.org
---
.../testing/selftests/drivers/net/hw/Makefile | 1 +
| 167 ++++++++++++++++++
2 files changed, 168 insertions(+)
create mode 100755 tools/testing/selftests/drivers/net/hw/rss_flow_label.py
diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
index fdc97355588c..5159fd34cb33 100644
--- a/tools/testing/selftests/drivers/net/hw/Makefile
+++ b/tools/testing/selftests/drivers/net/hw/Makefile
@@ -18,6 +18,7 @@ TEST_PROGS = \
pp_alloc_fail.py \
rss_api.py \
rss_ctx.py \
+ rss_flow_label.py \
rss_input_xfrm.py \
tso.py \
xsk_reconfig.py \
--git a/tools/testing/selftests/drivers/net/hw/rss_flow_label.py b/tools/testing/selftests/drivers/net/hw/rss_flow_label.py
new file mode 100755
index 000000000000..6fa95fe27c47
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/rss_flow_label.py
@@ -0,0 +1,167 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Tests for RSS hashing on IPv6 Flow Label.
+"""
+
+import glob
+import os
+import socket
+from lib.py import CmdExitFailure
+from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_ge, ksft_in, \
+ ksft_not_in, ksft_raises, KsftSkipEx
+from lib.py import bkg, cmd, defer, fd_read_timeout, rand_port
+from lib.py import NetDrvEpEnv
+
+
+def _check_system(cfg):
+ if not hasattr(socket, "SO_INCOMING_CPU"):
+ raise KsftSkipEx("socket.SO_INCOMING_CPU was added in Python 3.11")
+
+ qcnt = len(glob.glob(f"/sys/class/net/{cfg.ifname}/queues/rx-*"))
+ if qcnt < 2:
+ raise KsftSkipEx(f"Local has only {qcnt} queues")
+
+ for f in [f"/sys/class/net/{cfg.ifname}/queues/rx-0/rps_flow_cnt",
+ f"/sys/class/net/{cfg.ifname}/queues/rx-0/rps_cpus"]:
+ try:
+ with open(f, 'r') as fp:
+ setting = fp.read().strip()
+ # CPU mask will be zeros and commas
+ if setting.replace("0", "").replace(",", ""):
+ raise KsftSkipEx(f"RPS/RFS is configured: {f}: {setting}")
+ except FileNotFoundError:
+ pass
+
+ # 1 is the default, if someone changed it we probably shouldn"t mess with it
+ af = cmd("cat /proc/sys/net/ipv6/auto_flowlabels", host=cfg.remote).stdout
+ if af.strip() != "1":
+ raise KsftSkipEx("Remote does not have auto_flowlabels enabled")
+
+
+def _ethtool_get_cfg(cfg, fl_type):
+ descr = cmd(f"ethtool -n {cfg.ifname} rx-flow-hash {fl_type}").stdout
+
+ converter = {
+ "IP SA": "s",
+ "IP DA": "d",
+ "L3 proto": "t",
+ "L4 bytes 0 & 1 [TCP/UDP src port]": "f",
+ "L4 bytes 2 & 3 [TCP/UDP dst port]": "n",
+ "IPv6 Flow Label": "l",
+ }
+
+ ret = ""
+ for line in descr.split("\n")[1:-2]:
+ # if this raises we probably need to add more keys to converter above
+ ret += converter[line]
+ return ret
+
+
+def _traffic(cfg, one_sock, one_cpu):
+ local_port = rand_port(socket.SOCK_DGRAM)
+ remote_port = rand_port(socket.SOCK_DGRAM)
+
+ sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
+ sock.bind(("", local_port))
+ sock.connect((cfg.remote_addr_v["6"], 0))
+ if one_sock:
+ send = f"exec 5<>/dev/udp/{cfg.addr_v['6']}/{local_port}; " \
+ "for i in `seq 20`; do echo a >&5; sleep 0.02; done; exec 5>&-"
+ else:
+ send = "for i in `seq 20`; do echo a | socat -t0.02 - UDP6:" \
+ f"[{cfg.addr_v['6']}]:{local_port},sourceport={remote_port}; done"
+
+ cpus = set()
+ with bkg(send, shell=True, host=cfg.remote, exit_wait=True):
+ for _ in range(20):
+ fd_read_timeout(sock.fileno(), 1)
+ cpu = sock.getsockopt(socket.SOL_SOCKET, socket.SO_INCOMING_CPU)
+ cpus.add(cpu)
+
+ if one_cpu:
+ ksft_eq(len(cpus), 1,
+ f"{one_sock=} - expected one CPU, got traffic on: {cpus=}")
+ else:
+ ksft_ge(len(cpus), 2,
+ f"{one_sock=} - expected many CPUs, got traffic on: {cpus=}")
+
+
+def test_rss_flow_label(cfg):
+ """
+ Test hashing on IPv6 flow label. Send traffic over a single socket
+ and over multiple sockets. Depend on the remote having auto-label
+ enabled so that it randomizes the label per socket.
+ """
+
+ cfg.require_ipver("6")
+ cfg.require_cmd("socat", remote=True)
+ _check_system(cfg)
+
+ # Enable flow label hashing for UDP6
+ initial = _ethtool_get_cfg(cfg, "udp6")
+ no_lbl = initial.replace("l", "")
+ if "l" not in initial:
+ try:
+ cmd(f"ethtool -N {cfg.ifname} rx-flow-hash udp6 l{no_lbl}")
+ except CmdExitFailure as exc:
+ raise KsftSkipEx("Device doesn't support Flow Label for UDP6") from exc
+
+ defer(cmd, f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {initial}")
+
+ _traffic(cfg, one_sock=True, one_cpu=True)
+ _traffic(cfg, one_sock=False, one_cpu=False)
+
+ # Disable it, we should see no hashing (reset was already defer()ed)
+ cmd(f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {no_lbl}")
+
+ _traffic(cfg, one_sock=False, one_cpu=True)
+
+
+def _check_v4_flow_types(cfg):
+ for fl_type in ["tcp4", "udp4", "ah4", "esp4", "sctp4"]:
+ try:
+ cur = cmd(f"ethtool -n {cfg.ifname} rx-flow-hash {fl_type}").stdout
+ ksft_not_in("Flow Label", cur,
+ comment=f"{fl_type=} has Flow Label:" + cur)
+ except CmdExitFailure:
+ # Probably does not support this flow type
+ pass
+
+
+def test_rss_flow_label_6only(cfg):
+ """
+ Test interactions with IPv4 flow types. It should not be possible to set
+ IPv6 Flow Label hashing for an IPv4 flow type. The Flow Label should also
+ not appear in the IPv4 "current config".
+ """
+
+ with ksft_raises(CmdExitFailure) as cm:
+ cmd(f"ethtool -N {cfg.ifname} rx-flow-hash tcp4 sdfnl")
+ ksft_in("Invalid argument", cm.exception.cmd.stderr)
+
+ _check_v4_flow_types(cfg)
+
+ # Try to enable Flow Labels and check again, in case it leaks thru
+ initial = _ethtool_get_cfg(cfg, "udp6")
+ changed = initial.replace("l", "") if "l" in initial else initial + "l"
+
+ cmd(f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {changed}")
+ restore = defer(cmd, f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {initial}")
+
+ _check_v4_flow_types(cfg)
+ restore.exec()
+ _check_v4_flow_types(cfg)
+
+
+def main() -> None:
+ with NetDrvEpEnv(__file__, nsim_test=False) as cfg:
+ ksft_run([test_rss_flow_label,
+ test_rss_flow_label_6only],
+ args=(cfg, ))
+ ksft_exit()
+
+
+if __name__ == "__main__":
+ main()
--
2.50.1
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