Re: [PATCH v3 1/6] bpf: add new prog type for cgroup socket filtering

[Daniel Borkmann]

On 08/26/2016 09:58 PM, Daniel Mack wrote:

For now, this program type is equivalent to BPF_PROG_TYPE_SOCKET_FILTER in
terms of checks during the verification process. It may access the skb as
well.

Programs of this type will be attached to cgroups for network filtering
and accounting.

Signed-off-by: Daniel Mack <dan...@zonque.org>
---
  include/uapi/linux/bpf.h | 7 +++++++
  kernel/bpf/verifier.c    | 1 +
  net/core/filter.c        | 6 ++++++
  3 files changed, 14 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e4c5a1b..1d5db42 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -95,6 +95,13 @@ enum bpf_prog_type {
        BPF_PROG_TYPE_SCHED_ACT,
        BPF_PROG_TYPE_TRACEPOINT,
        BPF_PROG_TYPE_XDP,
+       BPF_PROG_TYPE_CGROUP_SOCKET_FILTER,
+};

Nit: can we drop the _FILTER suffix? So just leaving it
at BPF_PROG_TYPE_CGROUP_SOCKET. Some of these use cases
might not always strictly be related to filtering, so
seems cleaner to just leave it out everywhere.

+
+enum bpf_attach_type {
+       BPF_ATTACH_TYPE_CGROUP_INET_INGRESS,
+       BPF_ATTACH_TYPE_CGROUP_INET_EGRESS,
+       __MAX_BPF_ATTACH_TYPE
  };

#define BPF_MAX_ATTACH_TYPE     __BPF_MAX_ATTACH_TYPE

And then use that in your follow-up patches for declaring
arrays, etc?

  #define BPF_PSEUDO_MAP_FD     1
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index abb61f3..12ca880 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1805,6 +1805,7 @@ static bool may_access_skb(enum bpf_prog_type type)
        case BPF_PROG_TYPE_SOCKET_FILTER:
        case BPF_PROG_TYPE_SCHED_CLS:
        case BPF_PROG_TYPE_SCHED_ACT:
+       case BPF_PROG_TYPE_CGROUP_SOCKET_FILTER:
                return true;
        default:
                return false;
diff --git a/net/core/filter.c b/net/core/filter.c
index a83766b..bc04e5c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2848,12 +2848,18 @@ static struct bpf_prog_type_list xdp_type __read_mostly 
= {
        .type   = BPF_PROG_TYPE_XDP,
  };

+static struct bpf_prog_type_list cg_sk_filter_type __read_mostly = {
+       .ops    = &sk_filter_ops,
+       .type   = BPF_PROG_TYPE_CGROUP_SOCKET_FILTER,
+};
+
  static int __init register_sk_filter_ops(void)
  {
        bpf_register_prog_type(&sk_filter_type);
        bpf_register_prog_type(&sched_cls_type);
        bpf_register_prog_type(&sched_act_type);
        bpf_register_prog_type(&xdp_type);
+       bpf_register_prog_type(&cg_sk_filter_type);

        return 0;
  }