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=-5.8 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 6848CC64E75 for ; Thu, 26 Nov 2020 10:51:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05F9521D40 for ; Thu, 26 Nov 2020 10:51:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="h2SUC9oP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388499AbgKZKve (ORCPT ); Thu, 26 Nov 2020 05:51:34 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:22344 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726562AbgKZKve (ORCPT ); Thu, 26 Nov 2020 05:51:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606387892; 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=3gjiOuLAHt7YqrFLz1eLEvNsryaX1UyRkFt2nva2s6Y=; b=h2SUC9oPq51p9JOCE1BEPVfCwJyGKpT80TFPzuibNpOLwkpfpbevtCK3VdjXB3Un2FkAgp xJ9AhpvkVwb5f2p7gFkG6iXu4cyJogI3pJd8wB9i9pA9J+W3Iqi57znT87GmkUGXgO0I6w 1I1QY3l0famERTl00kudD3/6krzO6uc= 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-106-6unmhYAgPsSlmwKned8fRw-1; Thu, 26 Nov 2020 05:51:30 -0500 X-MC-Unique: 6unmhYAgPsSlmwKned8fRw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 606661005D55; Thu, 26 Nov 2020 10:51:29 +0000 (UTC) Received: from carbon (unknown [10.36.110.8]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7EE246085A; Thu, 26 Nov 2020 10:51:20 +0000 (UTC) Date: Thu, 26 Nov 2020 11:51:19 +0100 From: Jesper Dangaard Brouer To: Hangbin Liu Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, Daniel Borkmann , John Fastabend , Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= , Tariq Toukan , Maciej Fijalkowski , brouer@redhat.com Subject: Re: [PATCHv2 bpf-next] samples/bpf: add xdp program on egress for xdp_redirect_map Message-ID: <20201126115119.20f82cba@carbon> In-Reply-To: <20201126084325.477470-1-liuhangbin@gmail.com> References: <20201110124639.1941654-1-liuhangbin@gmail.com> <20201126084325.477470-1-liuhangbin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 26 Nov 2020 16:43:25 +0800 Hangbin Liu wrote: > Current sample test xdp_redirect_map only count pkts on ingress. But we > can't know whether the pkts are redirected or dropped. So add a counter > on egress interface so we could know how many pkts are redirect in fact. This is not true. The 2nd devmap XDP-prog will run in the same RX-context, so it doesn't tell us if the redirect was successful. I looked up the code, and the 2nd XDP-prog is even allowed to run when the egress driver doesn't support the NDO to xmit (dev->netdev_ops->ndo_xdp_xmit), which is very misleading, if you place a output counter here. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer static inline int __xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp, struct net_device *dev_rx) { struct xdp_frame *xdpf; int err; if (!dev->netdev_ops->ndo_xdp_xmit) return -EOPNOTSUPP; err = xdp_ok_fwd_dev(dev, xdp->data_end - xdp->data); if (unlikely(err)) return err; xdpf = xdp_convert_buff_to_frame(xdp); if (unlikely(!xdpf)) return -EOVERFLOW; bq_enqueue(dev, xdpf, dev_rx); return 0; } static struct xdp_buff *dev_map_run_prog(struct net_device *dev, struct xdp_buff *xdp, struct bpf_prog *xdp_prog) { struct xdp_txq_info txq = { .dev = dev }; u32 act; xdp_set_data_meta_invalid(xdp); xdp->txq = &txq; act = bpf_prog_run_xdp(xdp_prog, xdp); switch (act) { case XDP_PASS: return xdp; case XDP_DROP: break; default: bpf_warn_invalid_xdp_action(act); fallthrough; case XDP_ABORTED: trace_xdp_exception(dev, xdp_prog, act); break; } xdp_return_buff(xdp); return NULL; } int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp, struct net_device *dev_rx) { return __xdp_enqueue(dev, xdp, dev_rx); } int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, struct net_device *dev_rx) { struct net_device *dev = dst->dev; if (dst->xdp_prog) { xdp = dev_map_run_prog(dev, xdp, dst->xdp_prog); if (!xdp) return 0; } return __xdp_enqueue(dev, xdp, dev_rx); }