1 files changed, 164 insertions, 0 deletions
diff --git a/tools/testing/selftests/drivers/net/gro.py b/tools/testing/selftests/drivers/net/gro.py
new file mode 100755
index 000000000000..ba83713bf7b5
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/gro.py
@@ -0,0 +1,164 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+GRO (Generic Receive Offload) conformance tests.
+
+Validates that GRO coalescing works correctly by running the gro
+binary in different configurations and checking for correct packet
+coalescing behavior.
+
+Test cases:
+  - data: Data packets with same size/headers and correct seq numbers coalesce
+  - ack: Pure ACK packets do not coalesce
+  - flags: Packets with PSH, SYN, URG, RST flags do not coalesce
+  - tcp: Packets with incorrect checksum, non-consecutive seqno don't coalesce
+  - ip: Packets with different ECN, TTL, TOS, or IP options don't coalesce
+  - large: Packets larger than GRO_MAX_SIZE don't coalesce
+"""
+
+import os
+from lib.py import ksft_run, ksft_exit, ksft_pr
+from lib.py import NetDrvEpEnv, KsftXfailEx
+from lib.py import cmd, defer, bkg, ip
+from lib.py import ksft_variants
+
+
+def _resolve_dmac(cfg, ipver):
+    """
+    Find the destination MAC address remote host should use to send packets
+    towards the local host. It may be a router / gateway address.
+    """
+
+    attr = "dmac" + ipver
+    # Cache the response across test cases
+    if hasattr(cfg, attr):
+        return getattr(cfg, attr)
+
+    route = ip(f"-{ipver} route get {cfg.addr_v[ipver]}",
+               json=True, host=cfg.remote)[0]
+    gw = route.get("gateway")
+    # Local L2 segment, address directly
+    if not gw:
+        setattr(cfg, attr, cfg.dev['address'])
+        return getattr(cfg, attr)
+
+    # ping to make sure neighbor is resolved,
+    # bind to an interface, for v6 the GW is likely link local
+    cmd(f"ping -c1 -W0 -I{cfg.remote_ifname} {gw}", host=cfg.remote)
+
+    neigh = ip(f"neigh get {gw} dev {cfg.remote_ifname}",
+               json=True, host=cfg.remote)[0]
+    setattr(cfg, attr, neigh['lladdr'])
+    return getattr(cfg, attr)
+
+
+def _write_defer_restore(cfg, path, val, defer_undo=False):
+    with open(path, "r", encoding="utf-8") as fp:
+        orig_val = fp.read().strip()
+        if str(val) == orig_val:
+            return
+    with open(path, "w", encoding="utf-8") as fp:
+        fp.write(val)
+    if defer_undo:
+        defer(_write_defer_restore, cfg, path, orig_val)
+
+
+def _set_mtu_restore(dev, mtu, host):
+    if dev['mtu'] < mtu:
+        ip(f"link set dev {dev['ifname']} mtu {mtu}", host=host)
+        defer(ip, f"link set dev {dev['ifname']} mtu {dev['mtu']}", host=host)
+
+
+def _setup(cfg, test_name):
+    """ Setup hardware loopback mode for GRO testing. """
+
+    if not hasattr(cfg, "bin_remote"):
+        cfg.bin_local = cfg.test_dir / "gro"
+        cfg.bin_remote = cfg.remote.deploy(cfg.bin_local)
+
+    # "large" test needs at least 4k MTU
+    if test_name == "large":
+        _set_mtu_restore(cfg.dev, 4096, None)
+        _set_mtu_restore(cfg.remote_dev, 4096, cfg.remote)
+
+    flush_path = f"/sys/class/net/{cfg.ifname}/gro_flush_timeout"
+    irq_path = f"/sys/class/net/{cfg.ifname}/napi_defer_hard_irqs"
+
+    _write_defer_restore(cfg, flush_path, "200000", defer_undo=True)
+    _write_defer_restore(cfg, irq_path, "10", defer_undo=True)
+
+    try:
+        # Disable TSO for local tests
+        cfg.require_nsim()  # will raise KsftXfailEx if not running on nsim
+
+        cmd(f"ethtool -K {cfg.ifname} gro on tso off")
+        cmd(f"ethtool -K {cfg.remote_ifname} gro on tso off", host=cfg.remote)
+    except KsftXfailEx:
+        pass
+
+def _gro_variants():
+    """Generator that yields all combinations of protocol and test types."""
+
+    for protocol in ["ipv4", "ipv6", "ipip"]:
+        for test_name in ["data", "ack", "flags", "tcp", "ip", "large"]:
+            yield protocol, test_name
+
+
+@ksft_variants(_gro_variants())
+def test(cfg, protocol, test_name):
+    """Run a single GRO test with retries."""
+
+    ipver = "6" if protocol[-1] == "6" else "4"
+    cfg.require_ipver(ipver)
+
+    _setup(cfg, test_name)
+
+    base_cmd_args = [
+        f"--{protocol}",
+        f"--dmac {_resolve_dmac(cfg, ipver)}",
+        f"--smac {cfg.remote_dev['address']}",
+        f"--daddr {cfg.addr_v[ipver]}",
+        f"--saddr {cfg.remote_addr_v[ipver]}",
+        f"--test {test_name}",
+        "--verbose"
+    ]
+    base_args = " ".join(base_cmd_args)
+
+    # Each test is run 6 times to deflake, because given the receive timing,
+    # not all packets that should coalesce will be considered in the same flow
+    # on every try.
+    max_retries = 6
+    for attempt in range(max_retries):
+        rx_cmd = f"{cfg.bin_local} {base_args} --rx --iface {cfg.ifname}"
+        tx_cmd = f"{cfg.bin_remote} {base_args} --iface {cfg.remote_ifname}"
+
+        fail_now = attempt >= max_retries - 1
+
+        with bkg(rx_cmd, ksft_ready=True, exit_wait=True,
+                 fail=fail_now) as rx_proc:
+            cmd(tx_cmd, host=cfg.remote)
+
+        if rx_proc.ret == 0:
+            return
+
+        ksft_pr(rx_proc.stdout.strip().replace('\n', '\n# '))
+        ksft_pr(rx_proc.stderr.strip().replace('\n', '\n# '))
+
+        if test_name == "large" and os.environ.get("KSFT_MACHINE_SLOW"):
+            ksft_pr(f"Ignoring {protocol}/{test_name} failure due to slow environment")
+            return
+
+        ksft_pr(f"Attempt {attempt + 1}/{max_retries} failed, retrying...")
+
+
+def main() -> None:
+    """ Ksft boiler plate main """
+
+    with NetDrvEpEnv(__file__) as cfg:
+        ksft_run(cases=[test], args=(cfg,))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()