The virtio spec says:
If one of the VIRTIO_NET_F_HOST_TSO4, TSO6, USO or UFO options have
been negotiated:
If the VIRTIO_NET_F_GUEST_HDRLEN feature has been negotiated,
and gso_type differs from VIRTIO_NET_HDR_GSO_NONE, the driver
MUST set hdr_len to a value equal to the length of the headers,
including the transport header.
If the VIRTIO_NET_F_GUEST_HDRLEN feature has not been negotiated,
or gso_type is VIRTIO_NET_HDR_GSO_NONE, the driver SHOULD set
hdr_len to a value not less than the length of the headers,
including the transport header.
So if the VIRTIO_NET_F_GUEST_HDRLEN feature has been negotiated, the
hdr->hdr_len should be eth header + ip header + tcp/udp header.
But now:
hdr->hdr_len = __cpu_to_virtio15(little_endian, skb_headlen(skb));
The skb_headlen() returns the linear space of the skb, not the header
size that only match the case the VIRTIO_NET_F_GUEST_HDRLEN feature has
not been negotiated, or gso_type is VIRTIO_NET_HDR_GSO_NONE.
We do not check the feature of the device. This function is a common
function used by many places. So we do more stricter work whatever
the features is negotiated.
For the case skb_is_gso(skb) is false, if none of the
VIRTIO_NET_F_HOST_TSO4, TSO6, USO or UFO options have been negotiated,
the spec not define the action of setting hdr_len. Here I set it to
skb_headlen(). If one of the above features have been negotiated, we
should set a value not less than the length of "eth header + ip header +
tcp/udp header". So the skb_headlen() also is a valid value.
For the case skb_is_gso(skb) is true, it implies that one of
VIRTIO_NET_F_HOST_TSO4, TSO6, USO or UFO options MUST have been
negotiated. If the VIRTIO_NET_F_GUEST_HDRLEN is negotiated, we MUST set
it to the length of "eth header + ip header + tcp/udp header".
If the VIRTIO_NET_F_GUEST_HDRLEN is not negotiated, that still be a
valid value.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Reported-by: Spike Du <spiked@xxxxxxxxxx>
---
include/linux/virtio_net.h | 41 ++++++++++++++++++++++++++++----------
1 file changed, 31 insertions(+), 10 deletions(-)
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 4dfa9b69ca8d..51d93f9762d7 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -201,24 +201,45 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
if (skb_is_gso(skb)) {
struct skb_shared_info *sinfo = skb_shinfo(skb);
+ u32 hdrlen;
- /* 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)
+ if (sinfo->gso_type & SKB_GSO_TCPV4) {
hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
- else if (sinfo->gso_type & SKB_GSO_TCPV6)
+ hdrlen = tcp_hdrlen(skb) + skb_transport_offset(skb);
+
+ } else if (sinfo->gso_type & SKB_GSO_TCPV6) {
hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
- else if (sinfo->gso_type & SKB_GSO_UDP_L4)
+ hdrlen = tcp_hdrlen(skb) + skb_transport_offset(skb);
+
+ } else if (sinfo->gso_type & SKB_GSO_UDP_L4) {
hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP_L4;
- else
+ hdrlen = sizeof(struct udphdr) + skb_transport_offset(skb);
+
+ } else {
return -EINVAL;
+ }
+
+ /* One of VIRTIO_NET_F_HOST_TSO4, TSO6, USO or UFO options MUST
+ * have been negotiated. If the VIRTIO_NET_F_GUEST_HDRLEN is
+ * negotiated, we MUST set it to the length of "eth header + ip
+ * header + tcp/udp header". If the VIRTIO_NET_F_GUEST_HDRLEN
+ * is not negotiated, that still be a valid value.
+ */
+ hdr->hdr_len = __cpu_to_virtio16(little_endian, hdrlen);
+ hdr->gso_size = __cpu_to_virtio16(little_endian,
+ sinfo->gso_size);
+
if (sinfo->gso_type & SKB_GSO_TCP_ECN)
hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
- } else
+ } else {
+ /* If one of the VIRTIO_NET_F_HOST_TSO4, TSO6, USO or UFO
+ * options have been negotiated, we should set hdr_len to a
+ * value not less than the length of "eth header + ip header +
+ * tcp/udp header".
+ */
+ hdr->hdr_len = __cpu_to_virtio16(little_endian, skb_headlen(skb));
hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
+ }
if (skb->ip_summed == CHECKSUM_PARTIAL) {
hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
--
2.32.0.3.g01195cf9f
