From: Arthur Fabre <afabre@xxxxxxxxxxxxxx>
Use a bit in sk_buff to track whether or not an skb stores traits in
it's headroom.
It's tempting to store it in skb_shared_info like the XDP metadata,
but storing it in the skb allows us to more easily handle cases such as
skb clones in a few patches.
(I couldn't find an existing hole to use in sk_buff, so this makes a 4
byte hole... any pointers to a free bit?)
The following patches add support for handful of drivers, in the final
form we'd like to cover all drivers that currently support XDP metadata.
Signed-off-by: Arthur Fabre <afabre@xxxxxxxxxxxxxx>
---
include/linux/skbuff.h | 7 +++++++
include/net/xdp.h | 12 ++++++++++++
2 files changed, 19 insertions(+)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 03553c2200ab1c3750b799edb94fa3b94e11a5f1..d7dfee152ebd26ce87a230222e94076aca793adc 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -725,6 +725,12 @@ enum skb_tstamp_type {
__SKB_CLOCK_MAX = SKB_CLOCK_TAI,
};
+enum skb_traits_type {
+ SKB_TRAITS_NONE,
+ /* Trait store in headroom, offset by sizeof(struct xdp_frame) */
+ SKB_TRAITS_AFTER_XDP,
+};
+
/**
* DOC: Basic sk_buff geometry
*
@@ -1023,6 +1029,7 @@ struct sk_buff {
__u8 csum_not_inet:1;
#endif
__u8 unreadable:1;
+ __u8 traits_type:1; /* See enum skb_traits_type */
#if defined(CONFIG_NET_SCHED) || defined(CONFIG_NET_XGRESS)
__u16 tc_index; /* traffic control index */
#endif
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 84afe07d09efdb2ab0cb78b904f02cb74f9a56b6..e2e7c270efa3cbd11bddd234010b91daee5009a2 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -119,6 +119,12 @@ static __always_inline void xdp_buff_set_frag_pfmemalloc(struct xdp_buff *xdp)
static bool xdp_data_meta_unsupported(const struct xdp_buff *xdp);
static void xdp_set_data_meta_invalid(struct xdp_buff *xdp);
+static __always_inline void xdp_buff_update_skb(struct xdp_buff *xdp, struct sk_buff *skb)
+{
+ if (!xdp_data_meta_unsupported(xdp))
+ skb->traits_type = SKB_TRAITS_AFTER_XDP;
+}
+
static __always_inline void *xdp_buff_traits(const struct xdp_buff *xdp)
{
return xdp->data_hard_start + _XDP_FRAME_SIZE;
@@ -298,6 +304,12 @@ xdp_frame_is_frag_pfmemalloc(const struct xdp_frame *frame)
return !!(frame->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC);
}
+static __always_inline void xdp_frame_update_skb(struct xdp_frame *frame, struct sk_buff *skb)
+{
+ if (!frame->meta_unsupported)
+ skb->traits_type = SKB_TRAITS_AFTER_XDP;
+}
+
#define XDP_BULK_QUEUE_SIZE 16
struct xdp_frame_bulk {
int count;
--
2.43.0
