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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64216C433EF for ; Thu, 5 May 2022 05:55:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237374AbiEEF7R (ORCPT ); Thu, 5 May 2022 01:59:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231531AbiEEF7O (ORCPT ); Thu, 5 May 2022 01:59:14 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A748B1AD8E; Wed, 4 May 2022 22:55:34 -0700 (PDT) X-UUID: b391feff2acf4deea7391f61bc0538e2-20220505 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.4,REQID:3946083e-4c33-41de-bcf0-50e7fa125dcf,OB:0,LO B:0,IP:0,URL:8,TC:0,Content:0,EDM:0,RT:0,SF:100,FILE:0,RULE:Release_Ham,AC TION:release,TS:108 X-CID-INFO: VERSION:1.1.4,REQID:3946083e-4c33-41de-bcf0-50e7fa125dcf,OB:0,LOB: 0,IP:0,URL:8,TC:0,Content:0,EDM:0,RT:0,SF:100,FILE:0,RULE:Spam_GS981B3D,AC TION:quarantine,TS:108 X-CID-META: VersionHash:faefae9,CLOUDID:b2474316-2e53-443e-b81a-655c13977218,C OID:6060dbeaf70c,Recheck:0,SF:28|16|19|48,TC:nil,Content:0,EDM:-3,File:nil ,QS:0,BEC:nil X-UUID: b391feff2acf4deea7391f61bc0538e2-20220505 Received: from mtkcas10.mediatek.inc [(172.21.101.39)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1907580698; Thu, 05 May 2022 13:55:30 +0800 Received: from mtkmbs07n1.mediatek.inc (172.21.101.16) by mtkmbs10n2.mediatek.inc (172.21.101.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.3; Thu, 5 May 2022 13:55:29 +0800 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs07n1.mediatek.inc (172.21.101.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 5 May 2022 13:55:29 +0800 Received: from mbjsdccf07.mediatek.inc (10.15.20.246) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 5 May 2022 13:55:28 +0800 From: Lina Wang To: "David S . Miller" , Jakub Kicinski , Paolo Abeni , Shuah Khan , Matthias Brugger CC: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , "Jesper Dangaard Brouer" , Nathan Chancellor , "Nick Desaulniers" , Eric Dumazet , Willem de Bruijn , Maciej enczykowski , , , , , , , , Lina Wang Subject: [PATCH v6 1/2] net: fix wrong network header length Date: Thu, 5 May 2022 13:48:49 +0800 Message-ID: <20220505054850.4878-1-lina.wang@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org When clatd starts with ebpf offloaing, and NETIF_F_GRO_FRAGLIST is enable, several skbs are gathered in skb_shinfo(skb)->frag_list. The first skb's ipv6 header will be changed to ipv4 after bpf_skb_proto_6_to_4, network_header\transport_header\mac_header have been updated as ipv4 acts, but other skbs in frag_list didnot update anything, just ipv6 packets. udp_queue_rcv_skb will call skb_segment_list to traverse other skbs in frag_list and make sure right udp payload is delivered to user space. Unfortunately, other skbs in frag_list who are still ipv6 packets are updated like the first skb and will have wrong transport header length. e.g.before bpf_skb_proto_6_to_4,the first skb and other skbs in frag_list has the same network_header(24)& transport_header(64), after bpf_skb_proto_6_to_4, ipv6 protocol has been changed to ipv4, the first skb's network_header is 44,transport_header is 64, other skbs in frag_list didnot change.After skb_segment_list, the other skbs in frag_list has different network_header(24) and transport_header(44), so there will be 20 bytes different from original,that is difference between ipv6 header and ipv4 header. Just change transport_header to be the same with original. Actually, there are two solutions to fix it, one is traversing all skbs and changing every skb header in bpf_skb_proto_6_to_4, the other is modifying frag_list skb's header in skb_segment_list. Considering efficiency, adopt the second one--- when the first skb and other skbs in frag_list has different network_header length, restore them to make sure right udp payload is delivered to user space. Signed-off-by: Lina Wang --- net/core/skbuff.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 10bde7c6db44..e8006e0a1b25 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3897,7 +3897,7 @@ struct sk_buff *skb_segment_list(struct sk_buff *skb, unsigned int delta_len = 0; struct sk_buff *tail = NULL; struct sk_buff *nskb, *tmp; - int err; + int len_diff, err; skb_push(skb, -skb_network_offset(skb) + offset); @@ -3937,9 +3937,11 @@ struct sk_buff *skb_segment_list(struct sk_buff *skb, skb_push(nskb, -skb_network_offset(nskb) + offset); skb_release_head_state(nskb); + len_diff = skb_network_header_len(nskb) - skb_network_header_len(skb); __copy_skb_header(nskb, skb); skb_headers_offset_update(nskb, skb_headroom(nskb) - skb_headroom(skb)); + nskb->transport_header += len_diff; skb_copy_from_linear_data_offset(skb, -tnl_hlen, nskb->data - tnl_hlen, offset + tnl_hlen); -- 2.18.0