From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F29DC4338F for ; Wed, 25 Aug 2021 16:04:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9F4D611F0 for ; Wed, 25 Aug 2021 16:04:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232029AbhHYQFH (ORCPT ); Wed, 25 Aug 2021 12:05:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:48698 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234330AbhHYQFF (ORCPT ); Wed, 25 Aug 2021 12:05:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 531E161212; Wed, 25 Aug 2021 16:04:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629907459; bh=4PpP/xVSQQyMFeqCK4UU8Iiiit03YHt+jjy7lQiJThg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=LytHCMjaz2HLlW850RzBQGVKqF7KoVy0WOTohOx/nPOKNyNwaqoiSSdEBe/uPTVlk hzqIvXlyb3d/IkIxJEM6QhtWdxyloH1yT95UbvHj93U1eyBkOeiYWwrOKCJ5ysBh4t JyuER9108jK/lnaRwUNSGITdDOUdxe2ceQg/GJyHZcFV1XuUy653v945Kq0PK+Pq3v FFVuQuN2bQNNrjfM2RnOP94T8oqIm0oM87tBr0QXPgATjHxX/vbCYkxJgRG/eJsas8 BH9rLx/vVLQ/46FtNK1bmVRMA3uQBNziqoYEoLjfcU/TyqPxzX4XtJgWaaeObIBJc+ Gccv9t5NUWVSg== Date: Wed, 25 Aug 2021 09:04:18 -0700 From: Jakub Kicinski To: Eric Dumazet Cc: Zhongya Yan , netdev , LKML , Steven Rostedt , Ingo Molnar , David Miller , Hideaki YOSHIFUJI , David Ahern , hengqi.chen@gmail.com, Yonghong Song , ntspring@fb.com Subject: Re: [PATCH] net: tcp_drop adds `reason` parameter for tracing v2 Message-ID: <20210825090418.57fd7d2f@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: References: <20210825154043.247764-1-yan2228598786@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 25 Aug 2021 08:47:46 -0700 Eric Dumazet wrote: > On Wed, Aug 25, 2021 at 8:41 AM Zhongya Yan wrote: > > @@ -5703,15 +5700,15 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, > > TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); > > NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE); > > tcp_send_challenge_ack(sk, skb); > > - goto discard; > > + tcp_drop(sk, skb, TCP_DROP_MASK(__LINE__, TCP_VALIDATE_INCOMING)); > > I'd rather use a string. So that we can more easily identify _why_ the > packet was drop, without looking at the source code > of the exact kernel version to locate line number 1057 Yeah, the line number seems like a particularly bad idea. Hopefully strings won't be problematic, given we can expect most serious users to feed the tracepoints via BPF. enum would be more convenient there, I'd think. > You can be sure that we will get reports in the future from users of > heavily modified kernels. > Having to download a git tree, or apply semi-private patches is a no go. I'm slightly surprised by this angle. Are there downstream kernels with heavily modified TCP other than Google's? > If you really want to include __FILE__ and __LINE__, these both can be > stringified and included in the report, with the help of macros.