net: xdp: introduce bpf_xdp_pointer utility routine
Similar to skb_header_pointer, introduce bpf_xdp_pointer utility routine
to return a pointer to a given position in the xdp_buff if the requested
area (offset + len) is contained in a contiguous memory area otherwise it
will be copied in a bounce buffer provided by the caller.
Similar to the tc counterpart, introduce the two following xdp helpers:
- bpf_xdp_load_bytes
- bpf_xdp_store_bytes
Reviewed-by: Eelco Chaudron <echaudro@redhat.com>
Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/ab285c1efdd5b7a9d361348b1e7d3ef49f6382b3.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 5a28772..16a7574 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5060,6 +5060,22 @@
* Get the total size of a given xdp buff (linear and paged area)
* Return
* The total size of a given xdp buffer.
+ *
+ * long bpf_xdp_load_bytes(struct xdp_buff *xdp_md, u32 offset, void *buf, u32 len)
+ * Description
+ * This helper is provided as an easy way to load data from a
+ * xdp buffer. It can be used to load *len* bytes from *offset* from
+ * the frame associated to *xdp_md*, into the buffer pointed by
+ * *buf*.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_xdp_store_bytes(struct xdp_buff *xdp_md, u32 offset, void *buf, u32 len)
+ * Description
+ * Store *len* bytes from buffer *buf* into the frame
+ * associated to *xdp_md*, at *offset*.
+ * Return
+ * 0 on success, or a negative error in case of failure.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -5251,6 +5267,8 @@
FN(get_retval), \
FN(set_retval), \
FN(xdp_get_buff_len), \
+ FN(xdp_load_bytes), \
+ FN(xdp_store_bytes), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper