On Tue, Jun 21, 2016 at 06:15:13PM -0700, Alexei Starovoitov wrote:
> On Tue, Jun 21, 2016 at 05:23:21PM -0700, Martin KaFai Lau wrote:
> > Adds a bpf helper, bpf_skb_in_cgroup, to decide if a skb->sk
> > belongs to a descendant of a cgroup2. It is similar to the
> > feature added in netfilter:
> > commit c38c4597e4bf ("netfilter: implement xt_cgroup cgroup2 path match")
> >
> > The user is expected to populate a BPF_MAP_TYPE_CGROUP_ARRAY
> > which will be used by the bpf_skb_in_cgroup.
> >
> > Modifications to the bpf verifier is to ensure BPF_MAP_TYPE_CGROUP_ARRAY
> > and bpf_skb_in_cgroup() are always used together.
> >
> > Signed-off-by: Martin KaFai Lau <kafai@xxxxxx>
> > Cc: Alexei Starovoitov <ast@xxxxxx>
> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> > Cc: Tejun Heo <tj@xxxxxxxxxx>
> > ---
> > include/uapi/linux/bpf.h | 1 +
> > kernel/bpf/verifier.c | 8 ++++++++
> > net/core/filter.c | 36 ++++++++++++++++++++++++++++++++++++
> > 3 files changed, 45 insertions(+)
> >
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index ef4e386..a91714bd 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -314,6 +314,7 @@ enum bpf_func_id {
> > */
> > BPF_FUNC_skb_get_tunnel_opt,
> > BPF_FUNC_skb_set_tunnel_opt,
> > + BPF_FUNC_skb_in_cgroup,
> ...
> > +static u64 bpf_skb_in_cgroup(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
> > +{
> ...
> > + if (unlikely(!cgrp))
> > + return -ENOENT;
> > +
> > + return cgroup_is_descendant(sock_cgroup_ptr(&sk->sk_cgrp_data), cgrp);
>
> if you'd need to respin the patch for other reasons please add kdoc
> to bpf.h for this new helper similar to other helpers.
> To say that 0 or 1 return values is indication of cg2 descendant relation
> and < 0 in case of error.
Will do.
I will also address the '#ifndef CONFIG_CGROUPS' case in v2, as reported
by the kbuild test.
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