This is preparation for XDP TX and ndo_xdp_xmit.
This allows napi handler to handle xdp_frames through xdp ring as well
as sk_buff.
v8:
- Don't use xdp_frame pointer address to calculate skb->head and
headroom.
v7:
- Use xdp_scrub_frame() instead of memset().
v3:
- Revert v2 change around rings and use a flag to differentiate skb and
xdp_frame, since bulk skb xmit makes little performance difference
for now.
v2:
- Use another ring instead of using flag to differentiate skb and
xdp_frame. This approach makes bulk skb transmit possible in
veth_xmit later.
- Clear xdp_frame feilds in skb->head.
- Implement adjust_tail.
Signed-off-by: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp>
Acked-by: John Fastabend <john.fastab...@gmail.com>
---
drivers/net/veth.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 84 insertions(+), 5 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 9edf104..89f3059 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -22,12 +22,12 @@
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/ptr_ring.h>
-#include <linux/skb_array.h>
#include <linux/bpf_trace.h>
#define DRV_NAME "veth"
#define DRV_VERSION "1.0"
+#define VETH_XDP_FLAG BIT(0)
#define VETH_RING_SIZE 256
#define VETH_XDP_HEADROOM (XDP_PACKET_HEADROOM + NET_IP_ALIGN)
@@ -115,6 +115,24 @@ static void veth_get_ethtool_stats(struct net_device *dev,
/* general routines */
+static bool veth_is_xdp_frame(void *ptr)
+{
+ return (unsigned long)ptr & VETH_XDP_FLAG;
+}
+
+static void *veth_ptr_to_xdp(void *ptr)
+{
+ return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
+}
+
+static void veth_ptr_free(void *ptr)
+{
+ if (veth_is_xdp_frame(ptr))
+ xdp_return_frame(veth_ptr_to_xdp(ptr));
+ else
+ kfree_skb(ptr);
+}
+
static void __veth_xdp_flush(struct veth_priv *priv)
{
/* Write ptr_ring before reading rx_notify_masked */
@@ -249,6 +267,63 @@ static struct sk_buff *veth_build_skb(void *head, int
headroom, int len,
return skb;
}
+static struct sk_buff *veth_xdp_rcv_one(struct veth_priv *priv,
+ struct xdp_frame *frame)
+{
+ void *hard_start = frame->data - frame->headroom;
+ void *head = hard_start - sizeof(struct xdp_frame);
+ int len = frame->len, delta = 0;
+ struct bpf_prog *xdp_prog;
+ unsigned int headroom;
+ struct sk_buff *skb;
+
+ rcu_read_lock();
+ xdp_prog = rcu_dereference(priv->xdp_prog);
+ if (likely(xdp_prog)) {
+ struct xdp_buff xdp;
+ u32 act;
+
+ xdp.data_hard_start = hard_start;
+ xdp.data = frame->data;
+ xdp.data_end = frame->data + frame->len;
+ xdp.data_meta = frame->data - frame->metasize;
+ xdp.rxq = &priv->xdp_rxq;
+
+ act = bpf_prog_run_xdp(xdp_prog, &xdp);
+
+ switch (act) {
+ case XDP_PASS:
+ delta = frame->data - xdp.data;
+ len = xdp.data_end - xdp.data;
+ break;
+ default:
+ bpf_warn_invalid_xdp_action(act);
+ case XDP_ABORTED:
+ trace_xdp_exception(priv->dev, xdp_prog, act);
+ case XDP_DROP:
+ goto err_xdp;
+ }
+ }
+ rcu_read_unlock();
+
+ headroom = sizeof(struct xdp_frame) + frame->headroom - delta;
+ skb = veth_build_skb(head, headroom, len, 0);
+ if (!skb) {
+ xdp_return_frame(frame);
+ goto err;
+ }
+
+ xdp_scrub_frame(frame);
+ skb->protocol = eth_type_trans(skb, priv->dev);
+err:
+ return skb;
+err_xdp:
+ rcu_read_unlock();
+ xdp_return_frame(frame);
+
+ return NULL;
+}
+
static struct sk_buff *veth_xdp_rcv_skb(struct veth_priv *priv,
struct sk_buff *skb)
{
@@ -359,12 +434,16 @@ static int veth_xdp_rcv(struct veth_priv *priv, int
budget)
int i, done = 0;
for (i = 0; i < budget; i++) {
- struct sk_buff *skb = __ptr_ring_consume(&priv->xdp_ring);
+ void *ptr = __ptr_ring_consume(&priv->xdp_ring);
+ struct sk_buff *skb;
- if (!skb)
+ if (!ptr)
break;
- skb = veth_xdp_rcv_skb(priv, skb);
+ if (veth_is_xdp_frame(ptr))
+ skb = veth_xdp_rcv_one(priv, veth_ptr_to_xdp(ptr));
+ else
+ skb = veth_xdp_rcv_skb(priv, ptr);
if (skb)
napi_gro_receive(&priv->xdp_napi, skb);
@@ -417,7 +496,7 @@ static void veth_napi_del(struct net_device *dev)
napi_disable(&priv->xdp_napi);
netif_napi_del(&priv->xdp_napi);
priv->rx_notify_masked = false;
- ptr_ring_cleanup(&priv->xdp_ring, __skb_array_destroy_skb);
+ ptr_ring_cleanup(&priv->xdp_ring, veth_ptr_free);
}
static int veth_enable_xdp(struct net_device *dev)
--
1.8.3.1
