udp_vu: update segment size

In udp_vu_sock_recv(), collect a segment with a size defined to
IP_MAX_MTU + ETH_HLEN + sizeof(struct virtio_net_hdr_mrg_rxbuf)

The original version double counted the IP header: IP_MAX_MTU includes
the IP header, and so did hdrlen.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/udp_vu.c b/udp_vu.c
index 9c697f3..4123510 100644
--- a/udp_vu.c
+++ b/udp_vu.c
@@ -104,7 +104,8 @@ static int udp_vu_sock_recv(const struct ctx *c, int s, uint32_t events,
 	vu_init_elem(elem, iov_vu, VIRTQUEUE_MAX_SIZE);
 
 	iov_cnt = vu_collect(vdev, vq, elem, VIRTQUEUE_MAX_SIZE,
-			     IP_MAX_MTU - sizeof(struct udphdr) + hdrlen,
+			     IP_MAX_MTU + ETH_HLEN +
+			     sizeof(struct virtio_net_hdr_mrg_rxbuf),
 			     NULL);
 	if (iov_cnt == 0)
 		return 0;