From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-119.freemail.mail.aliyun.com (out30-119.freemail.mail.aliyun.com [115.124.30.119]) (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 299A93644C1 for ; Mon, 2 Mar 2026 09:04:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.119 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772442262; cv=none; b=HaRiGBjprX14BCxCqo9uMrFCQovGo446D/ZRJzJXXHwnl/T0VFlvh0l0GvozYp9mjCEcdKfEQKQRkkUH6hBafBi9xG9EWLAbU3eDAg8tT3V5mBT7LMim1RCuMSwHVH+myraAHV1Hhw/BwF8thPJdUpZllBCG7TrynQ2XqPyt/a0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772442262; c=relaxed/simple; bh=mg9TpiFcLsGtPNoUmtw3dtMT17dkIgq+HnkfknQKBNY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=OCa9XD487ZDLsZi1NFADL/TS4S4z1IEX0HXoEoReur3SrFtDcuouVe1GUYyq7dKhg67feoFM6xu6M7ZGG7fVdYiAbK2pn7s0oCJ0XTB6fWfCLGrzZ51Nrxj45vpmNRMdNGVsNtC97M/L/0ZpwivtH517D02kxWAriwZhFU9jIxE= 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=Fgqr7CD5; arc=none smtp.client-ip=115.124.30.119 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="Fgqr7CD5" 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=GZHe5g/FvtcoQAZypE3GZTUpsVtMQ3JGrxXyS85peuY=; b=Fgqr7CD5npfGVmqoEeMuiYdg040mTW0CVtSjFMy1RskUFc7odxKGnz0hO3coN7hVflxM2YNIVAjlQjWXBv/ZooU3+vvhc4ub5jOzGmrRDMsK7PQnJ6heC209XRX9aXGftTztL7KsrayZ21H8JLF8IG7DOwDiRCuVqDChQPOefTE= Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0X-2pCwl_1772442254 cluster:ay36) by smtp.aliyun-inc.com; Mon, 02 Mar 2026 17:04:14 +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 1/2] virtio-net: correct hdr_len handling for VIRTIO_NET_F_GUEST_HDRLEN Date: Mon, 2 Mar 2026 17:04:12 +0800 Message-Id: <20260302090413.86471-2-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 be50da3e9d4a ("net: virtio_net: implement exact header length guest feature") introduces support for the VIRTIO_NET_F_GUEST_HDRLEN feature in virtio-net. This feature requires virtio-net to set hdr_len to the actual header length of the packet when transmitting, the number of bytes from the start of the packet to the beginning of the transport-layer payload. However, in practice, hdr_len was being set using skb_headlen(skb), which is clearly incorrect. This commit fixes that issue. Fixes: be50da3e9d4a ("net: virtio_net: implement exact header length guest feature") Signed-off-by: Xuan Zhuo --- drivers/net/tun_vnet.h | 2 +- drivers/net/virtio_net.c | 8 +++-- include/linux/virtio_net.h | 61 ++++++++++++++++++++++++++++++-------- 3 files changed, 56 insertions(+), 15 deletions(-) diff --git a/drivers/net/tun_vnet.h b/drivers/net/tun_vnet.h index a5f93b6c4482..fa5cab9d3e55 100644 --- a/drivers/net/tun_vnet.h +++ b/drivers/net/tun_vnet.h @@ -244,7 +244,7 @@ tun_vnet_hdr_tnl_from_skb(unsigned int flags, if (virtio_net_hdr_tnl_from_skb(skb, tnl_hdr, has_tnl_offload, tun_vnet_is_little_endian(flags), - vlan_hlen, true)) { + vlan_hlen, true, false)) { struct virtio_net_hdr_v1 *hdr = &tnl_hdr->hash_hdr.hdr; struct skb_shared_info *sinfo = skb_shinfo(skb); diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 72d6a9c6a5a2..1800058c8072 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3265,9 +3265,13 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan) const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; struct virtnet_info *vi = sq->vq->vdev->priv; struct virtio_net_hdr_v1_hash_tunnel *hdr; - int num_sg; unsigned hdr_len = vi->hdr_len; + bool feature_hdrlen; bool can_push; + int num_sg; + + feature_hdrlen = virtio_has_feature(vi->vdev, + VIRTIO_NET_F_GUEST_HDRLEN); pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest); @@ -3288,7 +3292,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan) if (virtio_net_hdr_tnl_from_skb(skb, hdr, vi->tx_tnl, virtio_is_little_endian(vi->vdev), 0, - false)) + false, feature_hdrlen)) return -EPROTO; if (vi->mergeable_rx_bufs) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 75dabb763c65..d31c9af1f3d6 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -207,20 +207,40 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, return __virtio_net_hdr_to_skb(skb, hdr, little_endian, hdr->gso_type); } -static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, - struct virtio_net_hdr *hdr, - bool little_endian, - bool has_data_valid, - int vlan_hlen) +static inline void virtio_net_set_hdrlen(const struct sk_buff *skb, + struct virtio_net_hdr *hdr, + 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); + } else { + /* This is a hint as to how much should be linear. */ + hdr_len = skb_headlen(skb); + } + + hdr->hdr_len = __cpu_to_virtio16(little_endian, hdr_len); +} + +static inline int __virtio_net_hdr_from_skb(const struct sk_buff *skb, + struct virtio_net_hdr *hdr, + bool little_endian, + bool has_data_valid, + bool feature_hdrlen, + int vlan_hlen) { memset(hdr, 0, sizeof(*hdr)); /* no info leak */ if (skb_is_gso(skb)) { struct skb_shared_info *sinfo = skb_shinfo(skb); - /* This is a hint as to how much should be linear. */ - hdr->hdr_len = __cpu_to_virtio16(little_endian, - skb_headlen(skb)); hdr->gso_size = __cpu_to_virtio16(little_endian, sinfo->gso_size); if (sinfo->gso_type & SKB_GSO_TCPV4) @@ -231,6 +251,10 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP_L4; else return -EINVAL; + + virtio_net_set_hdrlen(skb, hdr, little_endian, + feature_hdrlen); + if (sinfo->gso_type & SKB_GSO_TCP_ECN) hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; } else @@ -250,6 +274,16 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, return 0; } +static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, + struct virtio_net_hdr *hdr, + bool little_endian, + bool has_data_valid, + int vlan_hlen) +{ + return __virtio_net_hdr_from_skb(skb, hdr, little_endian, + has_data_valid, false, vlan_hlen); +} + static inline unsigned int virtio_l3min(bool is_ipv6) { return is_ipv6 ? sizeof(struct ipv6hdr) : sizeof(struct iphdr); @@ -385,7 +419,8 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, bool tnl_hdr_negotiated, bool little_endian, int vlan_hlen, - bool has_data_valid) + bool has_data_valid, + bool feature_hdrlen) { struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)vhdr; unsigned int inner_nh, outer_th; @@ -395,8 +430,9 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, tnl_gso_type = skb_shinfo(skb)->gso_type & (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM); if (!tnl_gso_type) - return virtio_net_hdr_from_skb(skb, hdr, little_endian, - has_data_valid, vlan_hlen); + return __virtio_net_hdr_from_skb(skb, hdr, little_endian, + has_data_valid, + feature_hdrlen, vlan_hlen); /* Tunnel support not negotiated but skb ask for it. */ if (!tnl_hdr_negotiated) @@ -409,7 +445,8 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, /* 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, vlan_hlen); + 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