From patchwork Fri Nov 20 16:18:32 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: 329716 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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, 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 02975C64E7A for ; Fri, 20 Nov 2020 16:20:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C5A11223FD for ; Fri, 20 Nov 2020 16:20:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RYAkmeqr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729723AbgKTQUP (ORCPT ); Fri, 20 Nov 2020 11:20:15 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:30000 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729324AbgKTQSo (ORCPT ); Fri, 20 Nov 2020 11:18:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605889122; 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=lR6LRwt5kY60jExujJxu7l8pIugbjQBqiG7fK4HmMN8=; b=RYAkmeqrUVNB4F308vndyixPfRDMwRAaXDLXhnH4Ez16GjoC25MEkhI1VDWDGZj7UGeab0 FntQBPagvz9BNA3zyY29LGf/NMIG4NBQmtMj6xX7PUf/crZhIXeYdS7dNCvk21LTYfnrn1 3PFO5pY5HNuAimNdtpds6fvVJB6e1HY= 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-230-s17tS-21NravnwLMm0bsfg-1; Fri, 20 Nov 2020 11:18:38 -0500 X-MC-Unique: s17tS-21NravnwLMm0bsfg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BB49C100A640; Fri, 20 Nov 2020 16:18:36 +0000 (UTC) Received: from firesoul.localdomain (unknown [10.40.208.7]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3F89410016DB; Fri, 20 Nov 2020 16:18:33 +0000 (UTC) Received: from [192.168.42.3] (localhost [IPv6:::1]) by firesoul.localdomain (Postfix) with ESMTP id 3B0DB3213845D; Fri, 20 Nov 2020 17:18:32 +0100 (CET) Subject: [PATCH bpf-next V7 5/8] 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 , eyal.birger@gmail.com, colrack@gmail.com Date: Fri, 20 Nov 2020 17:18:32 +0100 Message-ID: <160588911217.2817268.18106787866302281725.stgit@firesoul> In-Reply-To: <160588903254.2817268.4861837335793475314.stgit@firesoul> References: <160588903254.2817268.4861837335793475314.stgit@firesoul> User-Agent: StGit/0.19 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The use-case for dropping the MTU check when TC-BPF does redirect to ingress, 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/ V4: - Keep net_device "up" (IFF_UP) check. - Adjustment to handle bpf_redirect_peer() helper Signed-off-by: Jesper Dangaard Brouer --- include/linux/netdevice.h | 31 +++++++++++++++++++++++++++++-- net/core/dev.c | 19 ++----------------- net/core/filter.c | 14 +++++++++++--- 3 files changed, 42 insertions(+), 22 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 7ce648a564f7..4a854e09e918 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3917,11 +3917,38 @@ int dev_forward_skb(struct net_device *dev, struct sk_buff *skb); bool is_skb_forwardable(const struct net_device *dev, const struct sk_buff *skb); +static __always_inline bool __is_skb_forwardable(const struct net_device *dev, + const struct sk_buff *skb, + const bool check_mtu) +{ + const u32 vlan_hdr_len = 4; /* VLAN_HLEN */ + unsigned int len; + + if (!(dev->flags & IFF_UP)) + return false; + + if (!check_mtu) + return true; + + len = dev->mtu + dev->hard_header_len + vlan_hdr_len; + if (skb->len <= len) + return true; + + /* if TSO is enabled, we don't care about the length as the packet + * could be forwarded without being segmented before + */ + if (skb_is_gso(skb)) + return true; + + return false; +} + static __always_inline int ____dev_forward_skb(struct net_device *dev, - struct sk_buff *skb) + struct sk_buff *skb, + const bool check_mtu) { if (skb_orphan_frags(skb, GFP_ATOMIC) || - unlikely(!is_skb_forwardable(dev, skb))) { + unlikely(!__is_skb_forwardable(dev, skb, check_mtu))) { 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 60d325bda0d7..6ceb6412ee97 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2189,28 +2189,13 @@ static inline void net_timestamp_set(struct sk_buff *skb) bool is_skb_forwardable(const struct net_device *dev, const struct sk_buff *skb) { - unsigned int len; - - if (!(dev->flags & IFF_UP)) - return false; - - len = dev->mtu + dev->hard_header_len + VLAN_HLEN; - if (skb->len <= len) - return true; - - /* if TSO is enabled, we don't care about the length as the packet - * could be forwarded without being segmented before - */ - if (skb_is_gso(skb)) - return true; - - return false; + return __is_skb_forwardable(dev, skb, true); } 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 d6125cfc49c3..4673afe59533 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; @@ -2480,7 +2488,7 @@ int skb_do_redirect(struct sk_buff *skb) goto out_drop; dev = ops->ndo_get_peer_dev(dev); if (unlikely(!dev || - !is_skb_forwardable(dev, skb) || + !__is_skb_forwardable(dev, skb, false) || net_eq(net, dev_net(dev)))) goto out_drop; skb->dev = dev; From patchwork Fri Nov 20 16:18:37 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: 329717 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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS autolearn=ham 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 34F5FC63777 for ; 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Fri, 20 Nov 2020 17:18:37 +0100 (CET) Subject: [PATCH bpf-next V7 6/8] 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, colrack@gmail.com Date: Fri, 20 Nov 2020 17:18:37 +0100 Message-ID: <160588911725.2817268.2911873075037298445.stgit@firesoul> In-Reply-To: <160588903254.2817268.4861837335793475314.stgit@firesoul> References: <160588903254.2817268.4861837335793475314.stgit@firesoul> User-Agent: StGit/0.19 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 6ceb6412ee97..26b40f8005ae 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3872,6 +3872,7 @@ 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; @@ -4963,6 +4964,7 @@ 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, From patchwork Fri Nov 20 16:18:42 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: 329718 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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, 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 B6E32C64E7D for ; Fri, 20 Nov 2020 16:19:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A3D522470 for ; Fri, 20 Nov 2020 16:19:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LoG1lpiK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729433AbgKTQSw (ORCPT ); Fri, 20 Nov 2020 11:18:52 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:21913 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729407AbgKTQSv (ORCPT ); Fri, 20 Nov 2020 11:18:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605889129; 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=iFs5YuS+UQBHxuk28XB6kdJ0sgDe9yXGAPFUS7xIqxM=; b=LoG1lpiK9+2g0roPaZvOE/vLkklvabUJw5n7YWbxbMyg6OxHIVQXrQPlkf7VG0pJ/g05gs gssjKWgvb7yVTFK14epVASTOCQy1+75nki/jSNMDJD+vL1Gyn26zGb99QwJZ5nmO7k9MlM xdN+rftz+nvdc+GyC5mQugJpIO1XhuY= 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-3-DkhjgBUgPC-z4C_y-vQ_zg-1; Fri, 20 Nov 2020 11:18:45 -0500 X-MC-Unique: DkhjgBUgPC-z4C_y-vQ_zg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B4EC4100C607; Fri, 20 Nov 2020 16:18:43 +0000 (UTC) Received: from firesoul.localdomain (unknown [10.40.208.7]) by smtp.corp.redhat.com (Postfix) with ESMTP id 625845D6AD; Fri, 20 Nov 2020 16:18:43 +0000 (UTC) Received: from [192.168.42.3] (localhost [IPv6:::1]) by firesoul.localdomain (Postfix) with ESMTP id 5D2ED3213845E; Fri, 20 Nov 2020 17:18:42 +0100 (CET) Subject: [PATCH bpf-next V7 7/8] selftests/bpf: use bpf_check_mtu in selftest test_cls_redirect 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, colrack@gmail.com Date: Fri, 20 Nov 2020 17:18:42 +0100 Message-ID: <160588912232.2817268.345692319346190004.stgit@firesoul> In-Reply-To: <160588903254.2817268.4861837335793475314.stgit@firesoul> References: <160588903254.2817268.4861837335793475314.stgit@firesoul> User-Agent: StGit/0.19 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This demonstrate how bpf_check_mtu() helper can easily be used together with bpf_skb_adjust_room() helper, prior to doing size adjustment, as delta argument is already setup. Hint: This specific test can be selected like this: ./test_progs -t cls_redirect Signed-off-by: Jesper Dangaard Brouer --- .../selftests/bpf/progs/test_cls_redirect.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/test_cls_redirect.c b/tools/testing/selftests/bpf/progs/test_cls_redirect.c index c9f8464996ea..3c1e042962e6 100644 --- a/tools/testing/selftests/bpf/progs/test_cls_redirect.c +++ b/tools/testing/selftests/bpf/progs/test_cls_redirect.c @@ -70,6 +70,7 @@ typedef struct { uint64_t errors_total_encap_adjust_failed; uint64_t errors_total_encap_buffer_too_small; uint64_t errors_total_redirect_loop; + uint64_t errors_total_encap_mtu_violate; } metrics_t; typedef enum { @@ -407,6 +408,7 @@ static INLINING ret_t forward_with_gre(struct __sk_buff *skb, encap_headers_t *e payload_off - sizeof(struct ethhdr) - sizeof(struct iphdr); int32_t delta = sizeof(struct gre_base_hdr) - encap_overhead; uint16_t proto = ETH_P_IP; + uint32_t mtu_len = 0; /* Loop protection: the inner packet's TTL is decremented as a safeguard * against any forwarding loop. As the only interesting field is the TTL @@ -479,6 +481,11 @@ static INLINING ret_t forward_with_gre(struct __sk_buff *skb, encap_headers_t *e } } + if (bpf_check_mtu(skb, skb->ifindex, &mtu_len, delta, 0)) { + metrics->errors_total_encap_mtu_violate++; + return TC_ACT_SHOT; + } + if (bpf_skb_adjust_room(skb, delta, BPF_ADJ_ROOM_NET, BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_NO_CSUM_RESET) ||