@@ -434,26 +434,59 @@ static int iov_fill(struct iovec *iov, int iovcnt, const void *buf, int count)
return offset;
}
+static int iov_skip(struct iovec *iov, int iovcnt, int count)
+{
+ int offset, i;
+
+ offset = i = 0;
+ while (offset < count && i < iovcnt) {
+ int len = MIN(iov[i].iov_len, count - offset);
+ iov[i].iov_base += len;
+ iov[i].iov_len -= len;
+ offset += len;
+ i++;
+ }
+
+ return offset;
+}
+
+static int iov_copy(struct iovec *to, struct iovec *from, int iovcnt, int count)
+{
+ int offset, i;
+
+ offset = i = 0;
+ while (offset < count && i < iovcnt) {
+ int len = MIN(from[i].iov_len, count - offset);
+ to[i].iov_base = from[i].iov_base;
+ to[i].iov_len = from[i].iov_len;
+ offset += len;
+ i++;
+ }
+
+ return i;
+}
+
static int receive_header(VirtIONet *n, struct iovec *iov, int iovcnt,
const void *buf, size_t size, size_t hdr_len)
{
- struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)iov[0].iov_base;
+ struct virtio_net_hdr hdr = {};
int offset = 0;
- hdr->flags = 0;
- hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
+ hdr.flags = 0;
+ hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
if (n->has_vnet_hdr) {
- memcpy(hdr, buf, sizeof(*hdr));
- offset = sizeof(*hdr);
- work_around_broken_dhclient(hdr, buf + offset, size - offset);
+ memcpy(&hdr, buf, sizeof hdr);
+ offset = sizeof hdr;
+ work_around_broken_dhclient(&hdr, buf + offset, size - offset);
}
+ iov_fill(iov, iovcnt, &hdr, sizeof hdr);
+
/* We only ever receive a struct virtio_net_hdr from the tapfd,
* but we may be passing along a larger header to the guest.
*/
- iov[0].iov_base += hdr_len;
- iov[0].iov_len -= hdr_len;
+ iov_skip(iov, iovcnt, hdr_len);
return offset;
}
@@ -514,7 +547,8 @@ static int receive_filter(VirtIONet *n, const uint8_t *buf, int size)
static ssize_t virtio_net_receive(VLANClientState *vc, const uint8_t *buf, size_t size)
{
VirtIONet *n = vc->opaque;
- struct virtio_net_hdr_mrg_rxbuf *mhdr = NULL;
+ struct iovec mhdr[VIRTQUEUE_MAX_SIZE];
+ int mhdrcnt = 0;
size_t hdr_len, offset, i;
if (!virtio_net_can_receive(n->vc))
@@ -552,16 +586,13 @@ static ssize_t virtio_net_receive(VLANClientState *vc, const uint8_t *buf, size_
exit(1);
}
- if (!n->mergeable_rx_bufs && elem.in_sg[0].iov_len != hdr_len) {
- fprintf(stderr, "virtio-net header not in first element\n");
- exit(1);
- }
-
memcpy(&sg, &elem.in_sg[0], sizeof(sg[0]) * elem.in_num);
if (i == 0) {
- if (n->mergeable_rx_bufs)
- mhdr = (struct virtio_net_hdr_mrg_rxbuf *)sg[0].iov_base;
+ if (n->mergeable_rx_bufs) {
+ mhdrcnt = iov_copy(mhdr, sg, elem.in_num,
+ sizeof(struct virtio_net_hdr_mrg_rxbuf));
+ }
offset += receive_header(n, sg, elem.in_num,
buf + offset, size - offset, hdr_len);
@@ -579,8 +610,12 @@ static ssize_t virtio_net_receive(VLANClientState *vc, const uint8_t *buf, size_
offset += len;
}
- if (mhdr)
- mhdr->num_buffers = i;
+ if (mhdrcnt) {
+ uint16_t num = i;
+ iov_skip(mhdr, mhdrcnt,
+ offsetof(struct virtio_net_hdr_mrg_rxbuf, num_buffers));
+ iov_fill(mhdr, mhdrcnt, &num, sizeof num);
+ }
virtqueue_flush(n->rx_vq, i);
virtio_notify(&n->vdev, n->rx_vq);
@@ -627,20 +662,19 @@ static void virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq)
sizeof(struct virtio_net_hdr_mrg_rxbuf) :
sizeof(struct virtio_net_hdr);
- if (out_num < 1 || out_sg->iov_len != hdr_len) {
- fprintf(stderr, "virtio-net header not in first element\n");
+ if (out_num < 1) {
+ fprintf(stderr, "virtio-net: no output element\n");
exit(1);
}
/* ignore the header if GSO is not supported */
if (!n->has_vnet_hdr) {
- out_num--;
- out_sg++;
+ iov_skip(out_sg, out_num, hdr_len);
len += hdr_len;
} else if (n->mergeable_rx_bufs) {
/* tapfd expects a struct virtio_net_hdr */
hdr_len -= sizeof(struct virtio_net_hdr);
- out_sg->iov_len -= hdr_len;
+ iov_skip(out_sg, out_num, hdr_len);
len += hdr_len;
}