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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 8A4B3C433E0 for ; Tue, 4 Aug 2020 21:58:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7768A22BED for ; Tue, 4 Aug 2020 21:58:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="b1QsIG/Q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728362AbgHDV6u (ORCPT ); Tue, 4 Aug 2020 17:58:50 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:37488 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728052AbgHDV6t (ORCPT ); Tue, 4 Aug 2020 17:58:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596578328; 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: in-reply-to:in-reply-to:references:references; bh=kBOKJp8w9KZXZuz53OUDNEXh+d4eCdFrJ20ncB3veo8=; b=b1QsIG/QVtQOkn4M7M2iKIg1Sy/sbsnP206MdiKwgyfNFYXcju5UVk4b+4weBgJ6Zp/GP+ T6xOutvq4JHM3YrWyhF3/uy/ccKabSeyjaJj9ZHC/x2m2SasDNUvpHaldxYLWuzUv3QsqH xcguSKJHsTUP9++qcGNCqolJP/34+ec= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-375-5AV7SC3ANV6U9ZNH25nRiA-1; Tue, 04 Aug 2020 17:58:39 -0400 X-MC-Unique: 5AV7SC3ANV6U9ZNH25nRiA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7483E1DE1; Tue, 4 Aug 2020 21:58:36 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-133.rdu2.redhat.com [10.10.113.133]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9845272E48; Tue, 4 Aug 2020 21:58:34 +0000 (UTC) Date: Tue, 4 Aug 2020 17:58:32 -0400 From: Neil Horman To: Cong Wang Cc: izabela.bakollari@gmail.com, Neil Horman , Linux Kernel Network Developers , LKML , Jakub Kicinski , linux-kernel-mentees@lists.linuxfoundation.org, David Miller Subject: Re: [Linux-kernel-mentees] [PATCHv2 net-next] dropwatch: Support monitoring of dropped frames Message-ID: <20200804215832.GB72184@localhost.localdomain> References: <20200707171515.110818-1-izabela.bakollari@gmail.com> <20200804160908.46193-1-izabela.bakollari@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Aug 04, 2020 at 02:28:28PM -0700, Cong Wang wrote: > On Tue, Aug 4, 2020 at 9:14 AM wrote: > > > > From: Izabela Bakollari > > > > Dropwatch is a utility that monitors dropped frames by having userspace > > record them over the dropwatch protocol over a file. This augument > > allows live monitoring of dropped frames using tools like tcpdump. > > > > With this feature, dropwatch allows two additional commands (start and > > stop interface) which allows the assignment of a net_device to the > > dropwatch protocol. When assinged, dropwatch will clone dropped frames, > > and receive them on the assigned interface, allowing tools like tcpdump > > to monitor for them. > > > > With this feature, create a dummy ethernet interface (ip link add dev > > dummy0 type dummy), assign it to the dropwatch kernel subsystem, by using > > these new commands, and then monitor dropped frames in real time by > > running tcpdump -i dummy0. > > drop monitor is already able to send dropped packets to user-space, > and wireshark already catches up with this feature: > > https://code.wireshark.org/review/gitweb?p=wireshark.git;a=commitdiff;h=a94a860c0644ec3b8a129fd243674a2e376ce1c8 > > So what you propose here seems pretty much a duplicate? > I had asked Izabela to implement this feature as an alternative approach to doing live capture of dropped packets, as part of the Linux foundation mentorship program. I'm supportive of this additional feature as the added code is fairly minimal, and allows for the use of other user space packet monitoring tools without additional code changes (i.e. tcpdump/snort/etc can now monitor dropped packets without the need to augment those tools with netlink capture code. Best Neil > Thanks. > _______________________________________________ > Linux-kernel-mentees mailing list > Linux-kernel-mentees@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees >