[PATCH net-next 3/3] selftests: drv-net: add a simple TSO test

Jakub Kicinski
2025-02-13T00:35:01Z

Add a simple test for TSO. Send a few MB of data and check device
stats to verify that the device was performing segmentation.
Do the same thing over a few tunnel types.

Injecting GSO packets directly would give us more ability to test
corner cases, but perhaps starting simple is good enough?

# ./ksft-net-drv/drivers/net/hw/tso.py
# Detected qstat for LSO wire-packets
KTAP version 1
1..14
ok 1 tso.ipv4 # SKIP Test requires IPv4 connectivity
ok 2 tso.vxlan4_ipv4 # SKIP Test requires IPv4 connectivity
ok 3 tso.vxlan6_ipv4 # SKIP Test requires IPv4 connectivity
ok 4 tso.vxlan_csum4_ipv4 # SKIP Test requires IPv4 connectivity
ok 5 tso.vxlan_csum6_ipv4 # SKIP Test requires IPv4 connectivity
ok 6 tso.gre4_ipv4 # SKIP Test requires IPv4 connectivity
ok 7 tso.gre6_ipv4 # SKIP Test requires IPv4 connectivity
ok 8 tso.ipv6
ok 9 tso.vxlan4_ipv6
ok 10 tso.vxlan6_ipv6
ok 11 tso.vxlan_csum4_ipv6
ok 12 tso.vxlan_csum6_ipv6
ok 13 tso.gre4_ipv6
ok 14 tso.gre6_ipv6
# Totals: pass:7 fail:0 xfail:0 xpass:0 skip:7 error:0

Note that the test currently depends on the driver reporting
the LSO count via qstat, which appears to be relatively rare
(virtio, cisco/enic, sfc/efc; but virtio needs host support).

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
.../testing/selftests/drivers/net/hw/Makefile | 1 +
tools/testing/selftests/drivers/net/hw/tso.py | 226 ++++++++++++++++++
2 files changed, 227 insertions(+)
create mode 100755 tools/testing/selftests/drivers/net/hw/tso.py

diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
index 21ba64ce1e34..ae783e18be83 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 \
+ tso.py \
#

TEST_FILES := \
diff --git a/tools/testing/selftests/drivers/net/hw/tso.py b/tools/testing/selftests/drivers/net/hw/tso.py
new file mode 100755
index 000000000000..ee3e207d85b3
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/tso.py
@@ -0,0 +1,226 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""Run the tools/testing/selftests/net/csum testsuite."""
+
+import fcntl
+import socket
+import struct
+import termios
+import time
+
+from lib.py import ksft_pr, ksft_run, ksft_exit, KsftSkipEx, KsftXfailEx
+from lib.py import ksft_eq, ksft_ge, ksft_lt
+from lib.py import EthtoolFamily, NetdevFamily, NetDrvEpEnv
+from lib.py import bkg, cmd, defer, ethtool, ip, rand_port, wait_port_listen
+
+
+def sock_wait_drain(sock, max_wait=1000):
+ """Wait for all pending write data on the socket to get ACKed."""
+ for _ in range(max_wait):
+ one = b'\0' * 4
+ outq = fcntl.ioctl(sock.fileno(), termios.TIOCOUTQ, one)
+ outq = struct.unpack("I", outq)[0]
+ if outq == 0:
+ break
+ time.sleep(0.01)
+ ksft_eq(outq, 0)
+
+
+def tcp_sock_get_retrans(sock):
+ """Get the number of retransmissions for the TCP socket."""
+ info = sock.getsockopt(socket.SOL_TCP, socket.TCP_INFO, 512)
+ return struct.unpack("I", info[100:104])[0]
+
+
+def run_one_stream(cfg, ipv4, remote_v4, remote_v6, should_lso):
+ cfg.require_cmd("socat", remote=True)
+
+ port = rand_port()
+ listen_cmd = f"socat -{cfg.addr_ipver} -t 2 -u TCP-LISTEN:{port},reuseport /dev/null,ignoreeof"
+
+ with bkg(listen_cmd, host=cfg.remote) as nc:
+ wait_port_listen(port, host=cfg.remote)
+
+ if ipv4:
+ sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+ sock.connect((remote_v4, port))
+ else:
+ sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+ sock.connect((remote_v6, port))
+
+ # Small send to make sure the connection is working.
+ sock.send("ping".encode())
+ sock_wait_drain(sock)
+
+ # Send 4MB of data, record the LSO packet count.
+ qstat_old = cfg.netnl.qstats_get({"ifindex": cfg.ifindex}, dump=True)[0]
+ buf = b"0" * 1024 * 1024 * 4
+ sock.send(buf)
+ sock_wait_drain(sock)
+ qstat_new = cfg.netnl.qstats_get({"ifindex": cfg.ifindex}, dump=True)[0]
+
+ # No math behind the 10 here, but try to catch cases where
+ # TCP falls back to non-LSO.
+ ksft_lt(tcp_sock_get_retrans(sock), 10)
+ sock.close()
+
+ # Check that at least 90% of the data was sent as LSO packets.
+ # System noise may cause false negatives, it is what it is.
+ total_lso_wire = len(buf) * 0.90 // cfg.dev["mtu"]
+ total_lso_super = len(buf) * 0.90 // cfg.dev["tso_max_size"]
+ if should_lso:
+ if cfg.have_stat_super_count:
+ ksft_ge(qstat_new['tx-hw-gso-packets'] -
+ qstat_old['tx-hw-gso-packets'],
+ total_lso_super,
+ comment="Number of LSO super-packets with LSO enabled")
+ if cfg.have_stat_wire_count:
+ ksft_ge(qstat_new['tx-hw-gso-wire-packets'] -
+ qstat_old['tx-hw-gso-wire-packets'],
+ total_lso_wire,
+ comment="Number of LSO wire-packets with LSO enabled")
+ else:
+ if cfg.have_stat_super_count:
+ ksft_lt(qstat_new['tx-hw-gso-packets'] -
+ qstat_old['tx-hw-gso-packets'],
+ 100, comment="Number of LSO super-packets with LSO disabled")
+ if cfg.have_stat_wire_count:
+ ksft_lt(qstat_new['tx-hw-gso-wire-packets'] -
+ qstat_old['tx-hw-gso-wire-packets'],
+ 1000, comment="Number of LSO wire-packets with LSO disabled")
+
+
+def build_tunnel(cfg, outer_ipv4, tun_info):
+ local_v4 = NetDrvEpEnv.nsim_v4_pfx + "1"
+ local_v6 = NetDrvEpEnv.nsim_v6_pfx + "1"
+ remote_v4 = NetDrvEpEnv.nsim_v4_pfx + "2"
+ remote_v6 = NetDrvEpEnv.nsim_v6_pfx + "2"
+
+ if outer_ipv4:
+ local_addr = cfg.v4
+ remote_addr = cfg.remote_v4
+ else:
+ local_addr = cfg.v6
+ remote_addr = cfg.remote_v6
+
+ tun_type = tun_info[0]
+ tun_arg = tun_info[1]
+ ip(f"link add {tun_type}-ksft type {tun_type} {tun_arg} local {local_addr} remote {remote_addr} dev {cfg.ifname}")
+ defer(ip, f"link del {tun_type}-ksft")
+ ip(f"link set dev {tun_type}-ksft up")
+ ip(f"addr add {local_v4}/24 dev {tun_type}-ksft")
+ ip(f"addr add {local_v6}/64 dev {tun_type}-ksft")
+
+ ip(f"link add {tun_type}-ksft type {tun_type} {tun_arg} local {remote_addr} remote {local_addr} dev {cfg.remote_ifname}",
+ host=cfg.remote)
+ defer(ip, f"link del {tun_type}-ksft", host=cfg.remote)
+ ip(f"link set dev {tun_type}-ksft up", host=cfg.remote)
+ ip(f"addr add {remote_v4}/24 dev {tun_type}-ksft", host=cfg.remote)
+ ip(f"addr add {remote_v6}/64 dev {tun_type}-ksft", host=cfg.remote)
+
+ return remote_v4, remote_v6
+
+
+def test_builder(name, cfg, ipv4, feature, tun=None, inner_ipv4=None):
+ """Construct specific tests from the common template."""
+ def f(cfg):
+ if ipv4:
+ cfg.require_v4()
+ else:
+ cfg.require_v6()
+
+ if not cfg.have_stat_super_count and \
+ not cfg.have_stat_wire_count:
+ raise KsftSkipEx(f"Device does not support LSO queue stats")
+
+ if tun:
+ remote_v4, remote_v6 = build_tunnel(cfg, ipv4, tun)
+ else:
+ remote_v4 = cfg.remote_v4
+ remote_v6 = cfg.remote_v6
+
+ has_gso_partial = tun and 'tx-gso-partial' in cfg.features
+
+ # First test without the feature enabled.
+ ethtool(f"-K {cfg.ifname} {feature} off")
+ if has_gso_partial:
+ ethtool(f"-K {cfg.ifname} tx-gso-partial off")
+ run_one_stream(cfg, ipv4, remote_v4, remote_v6, should_lso=False)
+
+ # Now test with the feature enabled.
+ if has_gso_partial:
+ ethtool(f"-K {cfg.ifname} tx-gso-partial on")
+ if feature in cfg.features:
+ ethtool(f"-K {cfg.ifname} {feature} on")
+ run_one_stream(cfg, ipv4, remote_v4, remote_v6, should_lso=True)
+ else:
+ raise KsftXfailEx(f"Device does not support {feature}")
+
+ if tun:
+ name += ("4" if inner_ipv4 else "6") + "_"
+ if ipv4:
+ f.__name__ = name + "ipv4"
+ else:
+ f.__name__ = name + "ipv6"
+ return f
+
+
+def query_nic_features(cfg) -> None:
+ """Query and cache the NIC features."""
+ cfg.features = set()
+
+ cfg.have_stat_super_count = False
+ cfg.have_stat_wire_count = False
+
+ features = cfg.ethnl.features_get({"header": {"dev-index": cfg.ifindex}})
+ for f in features["active"]["bits"]["bit"]:
+ cfg.features.add(f["name"])
+ for f in features["hw"]["bits"]["bit"]:
+ cfg.features.add(f["name"])
+
+ stats = cfg.netnl.qstats_get({"ifindex": cfg.ifindex}, dump=True)
+ if stats:
+ if 'tx-hw-gso-packets' in stats[0]:
+ ksft_pr("Detected qstat for LSO super-packets")
+ cfg.have_stat_super_count = True
+ if 'tx-hw-gso-wire-packets' in stats[0]:
+ ksft_pr("Detected qstat for LSO wire-packets")
+ cfg.have_stat_wire_count = True
+
+
+def main() -> None:
+ with NetDrvEpEnv(__file__, nsim_test=False) as cfg:
+ cfg.ethnl = EthtoolFamily()
+ cfg.netnl = NetdevFamily()
+
+ query_nic_features(cfg)
+
+ tun_info = (
+ # name, ethtool_feature tun:(type, args 4/6 only)
+ ("", "tx-tcp6-segmentation", None),
+ ("vxlan", "tx-udp_tnl-segmentation", ("vxlan", "id 100 dstport 4789 noudpcsum")),
+ ("vxlan_csum", "tx-udp_tnl-csum-segmentation", ("vxlan", "id 100 dstport 4789 udpcsum")),
+ ("gre", "tx-udp_tnl-segmentation", ("ipgre", "", True)),
+ ("gre", "tx-udp_tnl-segmentation", ("ip6gre", "", False)),
+ )
+
+ cases = []
+ for outer_ipv4 in [True, False]:
+ for info in tun_info:
+ # Skip if it's tunnel which only works for a specific IP version
+ if info[2] and len(info[2]) > 2 and outer_ipv4 != info[2][2]:
+ continue
+
+ cases.append(test_builder(info[0], cfg, outer_ipv4, info[1],
+ tun=info[2], inner_ipv4=True))
+ if info[2]:
+ cases.append(test_builder(info[0], cfg, outer_ipv4, info[1],
+ tun=info[2], inner_ipv4=False))
+
+ ksft_run(cases=cases, args=(cfg, ))
+ ksft_exit()
+
+
+if __name__ == "__main__":
+ main()
--
2.48.1