From patchwork Tue Oct 27 16:27:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jesper Dangaard Brouer X-Patchwork-Id: 11860797 X-Patchwork-Delegate: bpf@iogearbox.net 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=-9.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 85B7BC5517A for ; Tue, 27 Oct 2020 16:28:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3723720757 for ; Tue, 27 Oct 2020 16:28:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JjfyMlyd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1809793AbgJ0Q2i (ORCPT ); Tue, 27 Oct 2020 12:28:38 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:38516 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1809658AbgJ0Q1V (ORCPT ); Tue, 27 Oct 2020 12:27:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603816040; 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=bwTmwSFw/9HYws/MwgFi/u7T+cq4aSThDW49ZrCo2Mg=; b=JjfyMlydIY4gAxHYXFsYleoruxH6e7TWUGoJTzL7IHyfpsdk/ZkzNS76PqBhWbseN93YOR vPEIl8PZkPdKPr64Io67rnzDs+uh05E969kyeOMYPsg+rYVA79ULGzUUx3zmUTz2M07PVs VidULJSqZx6rzkykssW6vG0Yqm7B8sA= 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-518-IwpBzh88PpC3WP2keEaQ4w-1; Tue, 27 Oct 2020 12:27:16 -0400 X-MC-Unique: IwpBzh88PpC3WP2keEaQ4w-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4954361277; Tue, 27 Oct 2020 16:27:14 +0000 (UTC) Received: from firesoul.localdomain (unknown [10.40.208.22]) by smtp.corp.redhat.com (Postfix) with ESMTP id AE85E5D9E8; Tue, 27 Oct 2020 16:27:11 +0000 (UTC) Received: from [192.168.42.3] (localhost [IPv6:::1]) by firesoul.localdomain (Postfix) with ESMTP id 93AB130736C93; Tue, 27 Oct 2020 17:27:10 +0100 (CET) Subject: [PATCH bpf-next V4 5/5] bpf: make it possible to identify BPF redirected SKBs From: Jesper Dangaard Brouer To: bpf@vger.kernel.org Cc: Jesper Dangaard Brouer , netdev@vger.kernel.org, Daniel Borkmann , Alexei Starovoitov , maze@google.com, lmb@cloudflare.com, shaun@tigera.io, Lorenzo Bianconi , marek@cloudflare.com, John Fastabend , Jakub Kicinski , eyal.birger@gmail.com Date: Tue, 27 Oct 2020 17:27:10 +0100 Message-ID: <160381603052.1435097.17996668799662432883.stgit@firesoul> In-Reply-To: <160381592923.1435097.2008820753108719855.stgit@firesoul> References: <160381592923.1435097.2008820753108719855.stgit@firesoul> User-Agent: StGit/0.19 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This change makes it possible to identify SKBs that have been redirected by TC-BPF (cls_act). This is needed for a number of cases. (1) For collaborating with driver ifb net_devices. (2) For avoiding starting generic-XDP prog on TC ingress redirect. It is most important to fix XDP case(2), because this can break userspace when a driver gets support for native-XDP. Imagine userspace loads XDP prog on eth0, which fallback to generic-XDP, and it process TC-redirected packets. When kernel is updated with native-XDP support for eth0, then the program no-longer see the TC-redirected packets. Therefore it is important to keep the order intact; that XDP runs before TC-BPF. Signed-off-by: Jesper Dangaard Brouer --- net/core/dev.c | 2 ++ net/sched/Kconfig | 1 + 2 files changed, 3 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index 445ccf92c149..930c165a607e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3870,6 +3870,7 @@ sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev) return NULL; case TC_ACT_REDIRECT: /* No need to push/pop skb's mac_header here on egress! */ + skb_set_redirected(skb, false); skb_do_redirect(skb); *ret = NET_XMIT_SUCCESS; return NULL; @@ -4959,6 +4960,7 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret, * redirecting to another netdev */ __skb_push(skb, skb->mac_len); + skb_set_redirected(skb, true); if (skb_do_redirect(skb) == -EAGAIN) { __skb_pull(skb, skb->mac_len); *another = true; diff --git a/net/sched/Kconfig b/net/sched/Kconfig index a3b37d88800e..a1bbaa8fd054 100644 --- a/net/sched/Kconfig +++ b/net/sched/Kconfig @@ -384,6 +384,7 @@ config NET_SCH_INGRESS depends on NET_CLS_ACT select NET_INGRESS select NET_EGRESS + select NET_REDIRECT help Say Y here if you want to use classifiers for incoming and/or outgoing packets. This qdisc doesn't do anything else besides running classifiers,