On Fri, 12 Apr 2019, Willem de Bruijn wrote:
> From: Willem de Bruijn <will...@google.com>
>
> The ENCAP flags in bpf_skb_adjust_room are ignored on decap with
> bpf_skb_net_shrink. Reserve these bits for future use.
>
> Fixes: 868d523535c2d ("bpf: add bpf_skb_adjust_room encap flags")
> Signed-off-by: Willem de Bruijn <will...@google.com>
Reviewed-by: Alan Maguire <alan.magu...@oracle.com>
One thought; should we add a line to the growth-only flags in
the description of bpf_skb_adjust_room (ENCAP_L[234]) in bpf.h;
something like:
"This flag is valid for use with positive len_diff values only."
? Don't want to delay this patch with that suggestion though,
I can spin that up later.
> ---
> net/core/filter.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 95a27fdf9a405..bd1f51907b83b 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -3069,6 +3069,9 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32
> off, u32 len_diff,
> {
> int ret;
>
> + if (flags & ~BPF_F_ADJ_ROOM_FIXED_GSO)
> + return -EINVAL;
> +
> if (skb_is_gso(skb) && !skb_is_gso_tcp(skb)) {
> /* udp gso_size delineates datagrams, only allow if fixed */
> if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) ||
> --
> 2.21.0.392.gf8f6787159e-goog
>
>
