[PATCH 4.14 027/109] net/packet: fix packet drop as of virtio gso

Greg Kroah-Hartman
2018-10-16T17:18:05Z

From: Jianfeng Tan <jianfeng.tan@linux.alibaba.com>

[ Upstream commit 9d2f67e43b73e8af7438be219b66a5de0cfa8bd9 ]

When we use raw socket as the vhost backend, a packet from virito with
gso offloading information, cannot be sent out in later validaton at
xmit path, as we did not set correct skb->protocol which is further used
for looking up the gso function.

To fix this, we set this field according to virito hdr information.

Fixes: e858fae2b0b8f4 ("virtio_net: use common code for virtio_net_hdr and skb GSO conversion")
Signed-off-by: Jianfeng Tan <jianfeng.tan@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/virtio_net.h | 18 ++++++++++++++++++
net/packet/af_packet.c | 11 +++++++----
2 files changed, 25 insertions(+), 4 deletions(-)

--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -5,6 +5,24 @@
#include <linux/if_vlan.h>
#include <uapi/linux/virtio_net.h>

+static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,
+ const struct virtio_net_hdr *hdr)
+{
+ switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+ case VIRTIO_NET_HDR_GSO_TCPV4:
+ case VIRTIO_NET_HDR_GSO_UDP:
+ skb->protocol = cpu_to_be16(ETH_P_IP);
+ break;
+ case VIRTIO_NET_HDR_GSO_TCPV6:
+ skb->protocol = cpu_to_be16(ETH_P_IPV6);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
const struct virtio_net_hdr *hdr,
bool little_endian)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2753,10 +2753,12 @@ tpacket_error:
}
}

- if (po->has_vnet_hdr && virtio_net_hdr_to_skb(skb, vnet_hdr,
- vio_le())) {
- tp_len = -EINVAL;
- goto tpacket_error;
+ if (po->has_vnet_hdr) {
+ if (virtio_net_hdr_to_skb(skb, vnet_hdr, vio_le())) {
+ tp_len = -EINVAL;
+ goto tpacket_error;
+ }
+ virtio_net_hdr_set_proto(skb, vnet_hdr);
}

skb->destructor = tpacket_destruct_skb;
@@ -2952,6 +2954,7 @@ static int packet_snd(struct socket *soc
if (err)
goto out_free;
len += sizeof(vnet_hdr);
+ virtio_net_hdr_set_proto(skb, &vnet_hdr);
}

skb_probe_transport_header(skb, reserve);