#include <linux/module.h>
#include <linux/virtio.h>
#include <linux/virtio_net.h>
+#include <linux/bpf.h>
#include <linux/scatterlist.h>
#include <linux/if_vlan.h>
#include <linux/slab.h>
struct napi_struct napi;
+ struct bpf_prog __rcu *xdp_prog;
+
/* Chain pages by the private ptr. */
struct page *pages;
return skb;
}
+static u32 do_xdp_prog(struct virtnet_info *vi,
+ struct bpf_prog *xdp_prog,
+ struct page *page, int offset, int len)
+{
+ int hdr_padded_len;
+ struct xdp_buff xdp;
+ u32 act;
+ u8 *buf;
+
+ buf = page_address(page) + offset;
+
+ if (vi->mergeable_rx_bufs)
+ hdr_padded_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+ else
+ hdr_padded_len = sizeof(struct padded_vnet_hdr);
+
+ xdp.data = buf + hdr_padded_len;
+ xdp.data_end = xdp.data + (len - vi->hdr_len);
+
+ act = bpf_prog_run_xdp(xdp_prog, &xdp);
+ switch (act) {
+ case XDP_PASS:
+ return XDP_PASS;
+ default:
+ bpf_warn_invalid_xdp_action(act);
+ case XDP_TX:
+ case XDP_ABORTED:
+ case XDP_DROP:
+ return XDP_DROP;
+ }
+}
+
static struct sk_buff *receive_small(struct virtnet_info *vi, void *buf, unsigned int len)
{
struct sk_buff * skb = buf;
void *buf,
unsigned int len)
{
+ struct bpf_prog *xdp_prog;
struct page *page = buf;
- struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
+ struct sk_buff *skb;
+ rcu_read_lock();
+ xdp_prog = rcu_dereference(rq->xdp_prog);
+ if (xdp_prog) {
+ struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
+ u32 act;
+
+ if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags))
+ goto err_xdp;
+ act = do_xdp_prog(vi, xdp_prog, page, 0, len);
+ if (act == XDP_DROP)
+ goto err_xdp;
+ }
+ rcu_read_unlock();
+
+ skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
if (unlikely(!skb))
goto err;
return skb;
+err_xdp:
+ rcu_read_unlock();
err:
dev->stats.rx_dropped++;
give_pages(rq, page);
u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
struct page *page = virt_to_head_page(buf);
int offset = buf - page_address(page);
- unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
+ struct sk_buff *head_skb, *curr_skb;
+ struct bpf_prog *xdp_prog;
+ unsigned int truesize;
+
+ rcu_read_lock();
+ xdp_prog = rcu_dereference(rq->xdp_prog);
+ if (xdp_prog) {
+ u32 act;
+
+ /* No known backend devices should send packets with
+ * more than a single buffer when XDP conditions are
+ * met. However it is not strictly illegal so the case
+ * is handled as an exception and a warning is thrown.
+ */
+ if (unlikely(num_buf > 1)) {
+ bpf_warn_invalid_xdp_buffer();
+ goto err_xdp;
+ }
+
+ /* Transient failure which in theory could occur if
+ * in-flight packets from before XDP was enabled reach
+ * the receive path after XDP is loaded. In practice I
+ * was not able to create this condition.
+ */
+ if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags))
+ goto err_xdp;
+
+ act = do_xdp_prog(vi, xdp_prog, page, offset, len);
+ if (act == XDP_DROP)
+ goto err_xdp;
+ }
+ rcu_read_unlock();
- struct sk_buff *head_skb = page_to_skb(vi, rq, page, offset, len,
- truesize);
- struct sk_buff *curr_skb = head_skb;
+ truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
+ head_skb = page_to_skb(vi, rq, page, offset, len, truesize);
+ curr_skb = head_skb;
if (unlikely(!curr_skb))
goto err_skb;
ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);
return head_skb;
+err_xdp:
+ rcu_read_unlock();
err_skb:
put_page(page);
while (--num_buf) {
if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
return -EINVAL;
+ /* For now we don't support modifying channels while XDP is loaded
+ * also when XDP is loaded all RX queues have XDP programs so we only
+ * need to check a single RX queue.
+ */
+ if (vi->rq[0].xdp_prog)
+ return -EINVAL;
+
get_online_cpus();
err = virtnet_set_queues(vi, queue_pairs);
if (!err) {
.set_settings = virtnet_set_settings,
};
+static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog)
+{
+ unsigned long int max_sz = PAGE_SIZE - sizeof(struct padded_vnet_hdr);
+ struct virtnet_info *vi = netdev_priv(dev);
+ struct bpf_prog *old_prog;
+ int i;
+
+ if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
+ virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6)) {
+ netdev_warn(dev, "can't set XDP while host is implementing LRO, disable LRO first\n");
+ return -EOPNOTSUPP;
+ }
+
+ if (vi->mergeable_rx_bufs && !vi->any_header_sg) {
+ netdev_warn(dev, "XDP expects header/data in single page, any_header_sg required\n");
+ return -EINVAL;
+ }
+
+ if (dev->mtu > max_sz) {
+ netdev_warn(dev, "XDP requires MTU less than %lu\n", max_sz);
+ return -EINVAL;
+ }
+
+ if (prog) {
+ prog = bpf_prog_add(prog, vi->max_queue_pairs - 1);
+ if (IS_ERR(prog))
+ return PTR_ERR(prog);
+ }
+
+ for (i = 0; i < vi->max_queue_pairs; i++) {
+ old_prog = rtnl_dereference(vi->rq[i].xdp_prog);
+ rcu_assign_pointer(vi->rq[i].xdp_prog, prog);
+ if (old_prog)
+ bpf_prog_put(old_prog);
+ }
+
+ return 0;
+}
+
+static bool virtnet_xdp_query(struct net_device *dev)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ int i;
+
+ for (i = 0; i < vi->max_queue_pairs; i++) {
+ if (vi->rq[i].xdp_prog)
+ return true;
+ }
+ return false;
+}
+
+static int virtnet_xdp(struct net_device *dev, struct netdev_xdp *xdp)
+{
+ switch (xdp->command) {
+ case XDP_SETUP_PROG:
+ return virtnet_xdp_set(dev, xdp->prog);
+ case XDP_QUERY_PROG:
+ xdp->prog_attached = virtnet_xdp_query(dev);
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
static const struct net_device_ops virtnet_netdev = {
.ndo_open = virtnet_open,
.ndo_stop = virtnet_close,
#ifdef CONFIG_NET_RX_BUSY_POLL
.ndo_busy_poll = virtnet_busy_poll,
#endif
+ .ndo_xdp = virtnet_xdp,
};
static void virtnet_config_changed_work(struct work_struct *work)
static void free_receive_bufs(struct virtnet_info *vi)
{
+ struct bpf_prog *old_prog;
int i;
+ rtnl_lock();
for (i = 0; i < vi->max_queue_pairs; i++) {
while (vi->rq[i].pages)
__free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
+
+ old_prog = rtnl_dereference(vi->rq[i].xdp_prog);
+ RCU_INIT_POINTER(vi->rq[i].xdp_prog, NULL);
+ if (old_prog)
+ bpf_prog_put(old_prog);
}
+ rtnl_unlock();
}
static void free_receive_page_frags(struct virtnet_info *vi)
projects / kernel.git / commitdiff