Re: [PATCH net-next 09/12] selftests: drv-net: add a Python version of the GRO test

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

Jakub Kicinski wrote:
> Rewrite the existing gro.sh test in Python. The conversion
> not exact, the changes are related to integrating the test
> with our "remote endpoint" paradigm. The test now reads
> the IP addresses from the user config. It resolves the MAC
> address (including running over Layer 3 networks).
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>  tools/testing/selftests/drivers/net/Makefile |   2 +-
>  tools/testing/selftests/drivers/net/gro.c    |   3 +
>  tools/testing/selftests/drivers/net/gro.py   | 161 +++++++++++++++++++
>  tools/testing/selftests/drivers/net/gro.sh   | 105 ------------
>  4 files changed, 165 insertions(+), 106 deletions(-)
>  create mode 100755 tools/testing/selftests/drivers/net/gro.py
>  delete mode 100755 tools/testing/selftests/drivers/net/gro.sh
> 
> diff --git a/tools/testing/selftests/drivers/net/Makefile b/tools/testing/selftests/drivers/net/Makefile
> index 7083a8707c4e..f5c71d993750 100644
> --- a/tools/testing/selftests/drivers/net/Makefile
> +++ b/tools/testing/selftests/drivers/net/Makefile
> @@ -11,7 +11,7 @@ TEST_GEN_FILES := \
>  # end of TEST_GEN_FILES
>  
>  TEST_PROGS := \
> -	gro.sh \
> +	gro.py \
>  	hds.py \
>  	napi_id.py \
>  	napi_threaded.py \
> diff --git a/tools/testing/selftests/drivers/net/gro.c b/tools/testing/selftests/drivers/net/gro.c
> index 9b9be0cf8f7f..995b492f5bcb 100644
> --- a/tools/testing/selftests/drivers/net/gro.c
> +++ b/tools/testing/selftests/drivers/net/gro.c
> @@ -58,6 +58,7 @@
>  #include <unistd.h>
>  
>  #include "../../kselftest.h"
> +#include "../../net/lib/ksft.h"
>  
>  #define DPORT 8000
>  #define SPORT 1500
> @@ -1127,6 +1128,8 @@ static void gro_receiver(void)
>  	set_timeout(rxfd);
>  	bind_packetsocket(rxfd);
>  
> +	ksft_ready();
> +
>  	memset(correct_payload, 0, sizeof(correct_payload));
>  
>  	if (strcmp(testname, "data") == 0) {
> diff --git a/tools/testing/selftests/drivers/net/gro.py b/tools/testing/selftests/drivers/net/gro.py
> new file mode 100755
> index 000000000000..a27f8106eb63
> --- /dev/null
> +++ b/tools/testing/selftests/drivers/net/gro.py
> @@ -0,0 +1,161 @@
> +#!/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. I may be a router / gateway address.

I -> It

> +    """
> +
> +    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)