From patchwork Tue Oct 6 16:03:17 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: 11818889 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 01FCE112E for ; Tue, 6 Oct 2020 16:03:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DCCBC20760 for ; Tue, 6 Oct 2020 16:03:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="e1NxOMrV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726433AbgJFQD0 (ORCPT ); Tue, 6 Oct 2020 12:03:26 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:28537 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726012AbgJFQD0 (ORCPT ); Tue, 6 Oct 2020 12:03:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602000204; 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=7cCUdzva7bLz0RSwVhcNK+vXXtmrcUh6vXlo92Oj/LE=; b=e1NxOMrV/dInah+1vsxqkmkQufPCPVc+xVWgFeAvt1hM33vQ3FjSG9I2q/hCze6/Hl+OkI XTIPajR2GsgIlFJUCfH8Q9RXSZd3Sfugs03H0xgDn/u2/T4HJ7Lpr4U1fdIQ8Xs05WD00+ ClmoasSXO5GUSm7AJk7qnJLUmLd0zHY= 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-310-ROnGunCMO_aVcmjQ8Xpb1Q-1; Tue, 06 Oct 2020 12:03:23 -0400 X-MC-Unique: ROnGunCMO_aVcmjQ8Xpb1Q-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5FE20ADC23; Tue, 6 Oct 2020 16:03:21 +0000 (UTC) Received: from firesoul.localdomain (unknown [10.40.208.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id F1B721A8EC; Tue, 6 Oct 2020 16:03:17 +0000 (UTC) Received: from [192.168.42.3] (localhost [IPv6:::1]) by firesoul.localdomain (Postfix) with ESMTP id 0652E30736C8B; Tue, 6 Oct 2020 18:03:17 +0200 (CEST) Subject: [PATCH bpf-next V1 6/6] bpf: drop MTU check when doing TC-BPF redirect to ingress 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 Date: Tue, 06 Oct 2020 18:03:17 +0200 Message-ID: <160200019693.719143.11586734942253038578.stgit@firesoul> In-Reply-To: <160200013701.719143.12665708317930272219.stgit@firesoul> References: <160200013701.719143.12665708317930272219.stgit@firesoul> User-Agent: StGit/0.19 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org The use-case for dropping the MTU check when TC-BPF ingress redirecting a packet, is described by Eyal Birger in email[0]. The summary is the ability to increase packet size (e.g. with IPv6 headers for NAT64) and ingress redirect packet and let normal netstack fragment packet as needed. [0] https://lore.kernel.org/netdev/CAHsH6Gug-hsLGHQ6N0wtixdOa85LDZ3HNRHVd0opR=19Qo4W4Q@mail.gmail.com/ Signed-off-by: Jesper Dangaard Brouer --- include/linux/netdevice.h | 5 +++-- net/core/dev.c | 2 +- net/core/filter.c | 12 ++++++++++-- 3 files changed, 14 insertions(+), 5 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 28cfa53daf72..58fb7b4869ba 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3866,10 +3866,11 @@ bool is_skb_forwardable(const struct net_device *dev, const struct sk_buff *skb); static __always_inline int ____dev_forward_skb(struct net_device *dev, - struct sk_buff *skb) + struct sk_buff *skb, + const bool mtu_check) { if (skb_orphan_frags(skb, GFP_ATOMIC) || - unlikely(!is_skb_forwardable(dev, skb))) { + (mtu_check && unlikely(!is_skb_forwardable(dev, skb)))) { atomic_long_inc(&dev->rx_dropped); kfree_skb(skb); return NET_RX_DROP; diff --git a/net/core/dev.c b/net/core/dev.c index 33529022b30d..154c342bc061 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2209,7 +2209,7 @@ EXPORT_SYMBOL_GPL(is_skb_forwardable); int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb) { - int ret = ____dev_forward_skb(dev, skb); + int ret = ____dev_forward_skb(dev, skb, true); if (likely(!ret)) { skb->protocol = eth_type_trans(skb, dev); diff --git a/net/core/filter.c b/net/core/filter.c index 49ae3b80027b..69cd6de41f64 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2083,13 +2083,21 @@ static const struct bpf_func_proto bpf_csum_level_proto = { static inline int __bpf_rx_skb(struct net_device *dev, struct sk_buff *skb) { - return dev_forward_skb(dev, skb); + int ret = ____dev_forward_skb(dev, skb, false); + + if (likely(!ret)) { + skb->protocol = eth_type_trans(skb, dev); + skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN); + ret = netif_rx(skb); + } + + return ret; } static inline int __bpf_rx_skb_no_mac(struct net_device *dev, struct sk_buff *skb) { - int ret = ____dev_forward_skb(dev, skb); + int ret = ____dev_forward_skb(dev, skb, false); if (likely(!ret)) { skb->dev = dev;