From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84BA41798C; Tue, 19 Nov 2024 08:57:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732006642; cv=none; b=qo9IdJVfbTYP08XZGoc+kChPCqpkKKZ8aJcMgY+RlKpohFNzA9c/MmU9FokmMbKAeoYMP/zlkywdAbG1ELspXtZ5BAg6g9uVCYvo2zukLlJcbkr6K8VVNAh2vtuVcrUknbdPch3L4cEPmoG220BdTqfFI+Nkt/VW5es3azU8H5E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732006642; c=relaxed/simple; bh=01mOnY+a8qSh1SokfXxE9W5gK3wHTvzsLqt9Vk0HDG0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=XTj6vDJ9zUomyExd9+UR5HLI/S3VrtwswBNVEBo4lMu3dp5RasKYCfaqQPqwIue30dinnWHuqM+CnMBCzeKgPSIAgdT1mK9xyITYpuT3kJRKSLMBTVoiPw3WcLFFqTCLGZVC6lAJ8aCqKs4dgXvAq7xf3X+oIDWmptjQHkM5d4I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=X/p7my+z; arc=none smtp.client-ip=217.70.183.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="X/p7my+z" Received: by mail.gandi.net (Postfix) with ESMTPSA id 07C5740012; Tue, 19 Nov 2024 08:57:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1732006632; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qDLMX9bwiKUPXm5HqirAa1WgF18sn8QriLeZ4mKqO1s=; b=X/p7my+zUThqfZtd/oVsk84v3RaXRAVl04osFZ0G8CSXu1bzLEaNt7ygD6XcYFErj8UJk7 dtxVD5UquR/Goz8gYhMmqqI0712YnCZoiKAfqt3OyFh+keXS+0d5JCz2Y+sqwiKuRTnvM5 vG5ZbEnyVJPQXYVtuUAmcr7IPuTjV71yHL1pRL8RU0Df9Z5kWdEgX+irCnyUlsfn76lzSQ Exm6QG8MuTNTf1C09Qvm0PtW5mQWHOo9RUJzmvTUfgODq8vxtejUF5A65tKwg48wCf1tNj qAyBhSA/DQsBJXhCqmV7j3DcZy7IFuOHW/Fj1Wg9EJfZHlq4Xwxc4ppgIeNEwQ== Message-ID: <20802d12-004a-4b04-9b7d-93dc8b9866df@bootlin.com> Date: Tue, 19 Nov 2024 09:57:09 +0100 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next v2 11/13] selftests/bpf: add network helpers to generate udp checksums To: Stanislav Fomichev Cc: Andrii Nakryiko , Eduard Zingerman , Mykola Lysenko , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , "David S. Miller" , Jakub Kicinski , Jesper Dangaard Brouer , ebpf@linuxfoundation.org, Thomas Petazzoni , Bastien Curutchet , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org References: <20241114-flow_dissector-v2-0-ee4a3be3de65@bootlin.com> <20241114-flow_dissector-v2-11-ee4a3be3de65@bootlin.com> From: =?UTF-8?Q?Alexis_Lothor=C3=A9?= Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-GND-Sasl: alexis.lothore@bootlin.com On 11/15/24 16:54, Stanislav Fomichev wrote: > On 11/14, Alexis Lothoré (eBPF Foundation) wrote: >> +static inline __sum16 build_udp_v4_csum(const struct iphdr *iph, __u8 l4_proto, >> + __u16 l4_len, const void *l4_start, >> + int num_words) >> +{ >> + unsigned long pseudo_sum; >> + int num_u16 = sizeof(iph->saddr); /* halfwords: twice byte len */ >> + >> + pseudo_sum = add_csum_hword((void *)&iph->saddr, num_u16); >> + pseudo_sum += htons(l4_proto); >> + pseudo_sum += l4_len; >> + pseudo_sum += add_csum_hword(l4_start, num_words); >> + return csum_fold(pseudo_sum); > > I was expecting to see a call to csum_tcpudp_magic here. And csum_ipv6_magic > down below. These build pseudo header csum, so no need to manually do it > again. I initially tried to fit csum_tcpudp_magic here and did not manage to make a valid UDP checksum, but after more attempts, it looks like I had a misunderstanding this checksum computation. I am now able to used csum_tcpudp_magic in build_udp_v4_csum, it will be fixed in the next revision :) Thanks, Alexis -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com