From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-113.freemail.mail.aliyun.com (out30-113.freemail.mail.aliyun.com [115.124.30.113]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 79065313520 for ; Mon, 2 Mar 2026 09:04:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.113 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772442260; cv=none; b=ccZzBvJihvYDhGL5JEwTO/QN0RAdDANuD6XCwQXsVTcpIFeOs9jxocCtoRx4RV7ERyD68tFR2qghL+pB9Deg0QMmSQPP0Kuyg0zugsBgFUYYQmOU50pKAfjq/ZJz2jpHlVa+5YG9+awGdWjloykghpz8nnVkim3gWYfSVLhWTng= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772442260; c=relaxed/simple; bh=qs5px/UxujnucZ9qwyAOvbcd9+BtDKZc/LkcPUQjYtY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=tynBASM3EtEpTiYoe+pp6X5nte3sS9IskiTu2DnciqnyRvC1uSsiUDfw8p1c3TQQWBCtGDs3CFTk5JWCoK/dIzLoqmF7wWKZOY0hesBUI2I2F3AQtQYMag3WfCBFa2v+vTpNJLI3GZhZWktqRp5dRY/cpzeiYG0LGq88QPurHtA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=MuADD4L1; arc=none smtp.client-ip=115.124.30.113 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="MuADD4L1" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1772442256; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=rxlPX0OvoZIotLN2GYZBhe+6cISZ5dyHktquYK9IguM=; b=MuADD4L1vrtXhRq0NHzFBE0+jM3jriq60epKOXKokHVSsbcMc92WVdBiMBpKcyXJyKWbkq63kJu79cq8tpSyeR3zAu24P92cnQ8fZ7Z92+NkInEQq+yDvvmfyDPJynnCE+Nc+8OTrntt/GFL4nEGAUx5s/TwMza1i1rPbJMnkKE= Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0X-3.d7r_1772442254 cluster:ay36) by smtp.aliyun-inc.com; Mon, 02 Mar 2026 17:04:15 +0800 From: Xuan Zhuo To: netdev@vger.kernel.org Cc: Willem de Bruijn , Jason Wang , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "Michael S. Tsirkin" , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Jiri Pirko , Alvaro Karsz , virtualization@lists.linux.dev Subject: [PATCH net v7 2/2] virtio-net: correct hdr_len handling for tunnel gso Date: Mon, 2 Mar 2026 17:04:13 +0800 Message-Id: <20260302090413.86471-3-xuanzhuo@linux.alibaba.com> X-Mailer: git-send-email 2.32.0.3.g01195cf9f In-Reply-To: <20260302090413.86471-1-xuanzhuo@linux.alibaba.com> References: <20260302090413.86471-1-xuanzhuo@linux.alibaba.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Git-Hash: 411d21554521 Content-Transfer-Encoding: 8bit The commit a2fb4bc4e2a6a03 ("net: implement virtio helpers to handle UDP GSO tunneling.") introduces support for the UDP GSO tunnel feature in virtio-net. The virtio spec says: If the \field{gso_type} has the VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV4 bit or VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6 bit set, \field{hdr_len} accounts for all the headers up to and including the inner transport. The commit did not update the hdr_len to include the inner transport. I observed that the "hdr_len" is 116 for this packet: 17:36:18.241105 52:55:00:d1:27:0a > 2e:2c:df:46:a9:e1, ethertype IPv4 (0x0800), length 2912: (tos 0x0, ttl 64, id 45197, offset 0, flags [none], proto UDP (17), length 2898) 192.168.122.100.50613 > 192.168.122.1.4789: [bad udp cksum 0x8106 -> 0x26a0!] VXLAN, flags [I] (0x08), vni 1 fa:c3:ba:82:05:ee > ce:85:0c:31:77:e5, ethertype IPv4 (0x0800), length 2862: (tos 0x0, ttl 64, id 14678, offset 0, flags [DF], proto TCP (6), length 2848) 192.168.3.1.49880 > 192.168.3.2.9898: Flags [P.], cksum 0x9266 (incorrect -> 0xaa20), seq 515667:518463, ack 1, win 64, options [nop,nop,TS val 2990048824 ecr 2798801412], length 2796 116 = 14(mac) + 20(ip) + 8(udp) + 8(vxlan) + 14(inner mac) + 20(inner ip) + 32(innner tcp) Fixes: a2fb4bc4e2a6a03 ("net: implement virtio helpers to handle UDP GSO tunneling.") Signed-off-by: Xuan Zhuo --- include/linux/virtio_net.h | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index d31c9af1f3d6..906157779955 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -209,18 +209,29 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, static inline void virtio_net_set_hdrlen(const struct sk_buff *skb, struct virtio_net_hdr *hdr, + struct skb_shared_info *sinfo, bool little_endian, bool feature_hdrlen) { u16 hdr_len; if (feature_hdrlen) { - hdr_len = skb_transport_offset(skb); - - if (hdr->gso_type == VIRTIO_NET_HDR_GSO_UDP_L4) - hdr_len += sizeof(struct udphdr); - else - hdr_len += tcp_hdrlen(skb); + if (sinfo->gso_type & (SKB_GSO_UDP_TUNNEL | + SKB_GSO_UDP_TUNNEL_CSUM)) { + hdr_len = skb_inner_transport_offset(skb); + + if (hdr->gso_type == VIRTIO_NET_HDR_GSO_UDP_L4) + hdr_len += sizeof(struct udphdr); + else + hdr_len += inner_tcp_hdrlen(skb); + } else { + hdr_len = skb_transport_offset(skb); + + if (hdr->gso_type == VIRTIO_NET_HDR_GSO_UDP_L4) + hdr_len += sizeof(struct udphdr); + else + hdr_len += tcp_hdrlen(skb); + } } else { /* This is a hint as to how much should be linear. */ hdr_len = skb_headlen(skb); @@ -252,7 +263,7 @@ static inline int __virtio_net_hdr_from_skb(const struct sk_buff *skb, else return -EINVAL; - virtio_net_set_hdrlen(skb, hdr, little_endian, + virtio_net_set_hdrlen(skb, hdr, sinfo, little_endian, feature_hdrlen); if (sinfo->gso_type & SKB_GSO_TCP_ECN) @@ -443,11 +454,8 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, vhdr->hash_hdr.hash_report = 0; vhdr->hash_hdr.padding = 0; - /* Let the basic parsing deal with plain GSO features. */ - skb_shinfo(skb)->gso_type &= ~tnl_gso_type; ret = __virtio_net_hdr_from_skb(skb, hdr, true, false, feature_hdrlen, vlan_hlen); - skb_shinfo(skb)->gso_type |= tnl_gso_type; if (ret) return ret; -- 2.32.0.3.g01195cf9f