}
/* Offloading manipulation support callbacks. */
-static bool netmap_has_ufo(NetClientState *nc)
+static int netmap_fd_set_vnet_hdr_len(NetmapState *s, int len)
{
- return true;
+ struct nmreq req;
+
+ /* Issue a NETMAP_BDG_VNET_HDR command to change the virtio-net header
+ * length for the netmap adapter associated to 's->ifname'.
+ */
+ memset(&req, 0, sizeof(req));
+ pstrcpy(req.nr_name, sizeof(req.nr_name), s->ifname);
+ req.nr_version = NETMAP_API;
+ req.nr_cmd = NETMAP_BDG_VNET_HDR;
+ req.nr_arg1 = len;
+
+ return ioctl(s->nmd->fd, NIOCREGIF, &req);
}
-static bool netmap_has_vnet_hdr(NetClientState *nc)
+static bool netmap_has_vnet_hdr_len(NetClientState *nc, int len)
{
+ NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
+ int prev_len = s->vnet_hdr_len;
+
+ /* Check that we can set the new length. */
+ if (netmap_fd_set_vnet_hdr_len(s, len)) {
+ return false;
+ }
+
+ /* Restore the previous length. */
+ if (netmap_fd_set_vnet_hdr_len(s, prev_len)) {
+ error_report("Failed to restore vnet-hdr length %d on %s: %s",
+ prev_len, s->ifname, strerror(errno));
+ abort();
+ }
+
return true;
}
-static bool netmap_has_vnet_hdr_len(NetClientState *nc, int len)
+/* A netmap interface that supports virtio-net headers always
+ * supports UFO, so we use this callback also for the has_ufo hook. */
+static bool netmap_has_vnet_hdr(NetClientState *nc)
{
- return len == 0 || len == sizeof(struct virtio_net_hdr) ||
- len == sizeof(struct virtio_net_hdr_mrg_rxbuf);
+ return netmap_has_vnet_hdr_len(nc, sizeof(struct virtio_net_hdr));
}
static void netmap_using_vnet_hdr(NetClientState *nc, bool enable)
{
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
int err;
- struct nmreq req;
- /* Issue a NETMAP_BDG_VNET_HDR command to change the virtio-net header
- * length for the netmap adapter associated to 's->ifname'.
- */
- memset(&req, 0, sizeof(req));
- pstrcpy(req.nr_name, sizeof(req.nr_name), s->ifname);
- req.nr_version = NETMAP_API;
- req.nr_cmd = NETMAP_BDG_VNET_HDR;
- req.nr_arg1 = len;
- err = ioctl(s->nmd->fd, NIOCREGIF, &req);
+ err = netmap_fd_set_vnet_hdr_len(s, len);
if (err) {
- error_report("Unable to execute NETMAP_BDG_VNET_HDR on %s: %s",
- s->ifname, strerror(errno));
+ error_report("Unable to set vnet-hdr length %d on %s: %s",
+ len, s->ifname, strerror(errno));
} else {
/* Keep track of the current length. */
s->vnet_hdr_len = len;
NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
/* Setting a virtio-net header length greater than zero automatically
- * enables the offloadings.
- */
+ * enables the offloadings. */
if (!s->vnet_hdr_len) {
netmap_set_vnet_hdr_len(nc, sizeof(struct virtio_net_hdr));
}
.receive_iov = netmap_receive_iov,
.poll = netmap_poll,
.cleanup = netmap_cleanup,
- .has_ufo = netmap_has_ufo,
+ .has_ufo = netmap_has_vnet_hdr,
.has_vnet_hdr = netmap_has_vnet_hdr,
.has_vnet_hdr_len = netmap_has_vnet_hdr_len,
.using_vnet_hdr = netmap_using_vnet_hdr,