diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2016-08-18 01:00:39 +0200 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2022-04-19 00:50:35 +0300 |
| commit | 7a0f966b3bec1aaf049a7510c49f3b04d45eec3b (patch) | |
| tree | 06d30828845b95749930ae53dc18bcbe30959e12 /include/uapi/linux/bpf.h | |
| parent | 0d35a9dd1aa087e8ac22f01c3fc6d7c94fac22aa (diff) | |
bpf: add bpf_skb_change_tail helper
This work adds a bpf_skb_change_tail() helper for tc BPF programs. The
basic idea is to expand or shrink the skb in a controlled manner. The
eBPF program can then rewrite the rest via helpers like bpf_skb_store_bytes(),
bpf_lX_csum_replace() and others rather than passing a raw buffer for
writing here.
bpf_skb_change_tail() is really a slow path helper and intended for
replies with f.e. ICMP control messages. Concept is similar to other
helpers like bpf_skb_change_proto() helper to keep the helper without
protocol specifics and let the BPF program mangle the remaining parts.
A flags field has been added and is reserved for now should we extend
the helper in future.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
Diffstat (limited to 'include/uapi/linux/bpf.h')
| -rw-r--r-- | include/uapi/linux/bpf.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c051464e2900..c353defa9692 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -386,6 +386,17 @@ enum bpf_func_id { */ BPF_FUNC_current_task_under_cgroup, + /** + * bpf_skb_change_tail(skb, len, flags) + * The helper will resize the skb to the given new size, + * to be used f.e. with control messages. + * @skb: pointer to skb + * @len: new skb length + * @flags: reserved + * Return: 0 on success or negative error + */ + BPF_FUNC_skb_change_tail, + __BPF_FUNC_MAX_ID, }; |