bpf: allow BPF read access to qdisc pkt_len
The pkt_len field in qdisc_skb_cb stores the skb length as it will
appear on the wire after segmentation. For byte accounting, this value
is more accurate than skb->len. It is computed on entry to the TC
layer, so only valid there.
Allow read access to this field from BPF tc classifier and action
programs. The implementation is analogous to tc_classid, aside from
restricting to read access.
To distinguish it from skb->len and self-describe export as wire_len.
Changes v1->v2
- Rename pkt_len to wire_len
Signed-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Vlad Dumitrescu <vladum@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 8050cae..0183b8e 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2497,6 +2497,7 @@
__u32 data_meta;
struct bpf_flow_keys *flow_keys;
__u64 tstamp;
+ __u32 wire_len;
};
struct bpf_tunnel_key {