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authorMartin KaFai Lau <kafai@fb.com>2016-12-07 15:53:11 -0800
committerDavid S. Miller <davem@davemloft.net>2016-12-08 14:25:13 -0500
commit17bedab2723145d17b14084430743549e6943d03 (patch)
tree6a1517e36c1be543f591b5ff7fcd7e816dcc906a /include/uapi
parent8a03cf2cb7efe269913db079afb8c31f20bf0bef (diff)
bpf: xdp: Allow head adjustment in XDP prog
This patch allows XDP prog to extend/remove the packet data at the head (like adding or removing header). It is done by adding a new XDP helper bpf_xdp_adjust_head(). It also renames bpf_helper_changes_skb_data() to bpf_helper_changes_pkt_data() to better reflect that XDP prog does not work on skb. This patch adds one "xdp_adjust_head" bit to bpf_prog for the XDP-capable driver to check if the XDP prog requires bpf_xdp_adjust_head() support. The driver can then decide to error out during XDP_SETUP_PROG. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/uapi')
-rw-r--r--include/uapi/linux/bpf.h11
1 files changed, 10 insertions, 1 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 6123d9b8e828..0eb0e87dbe9f 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -424,6 +424,12 @@ union bpf_attr {
* @len: length of header to be pushed in front
* @flags: Flags (unused for now)
* Return: 0 on success or negative error
+ *
+ * int bpf_xdp_adjust_head(xdp_md, delta)
+ * Adjust the xdp_md.data by delta
+ * @xdp_md: pointer to xdp_md
+ * @delta: An positive/negative integer to be added to xdp_md.data
+ * Return: 0 on success or negative on error
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -469,7 +475,8 @@ union bpf_attr {
FN(csum_update), \
FN(set_hash_invalid), \
FN(get_numa_node_id), \
- FN(skb_change_head),
+ FN(skb_change_head), \
+ FN(xdp_adjust_head),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
@@ -576,6 +583,8 @@ struct bpf_sock {
__u32 protocol;
};
+#define XDP_PACKET_HEADROOM 256
+
/* User return codes for XDP prog type.
* A valid XDP program must return one of these defined values. All other
* return codes are reserved for future use. Unknown return codes will result