[RFC PATCH 1/5] bpf: add new prog type for cgroup socket filtering

[Daniel Mack <daniel@zonque.org>]

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 <daniel@zonque.org>
---
 include/uapi/linux/bpf.h | 1 +
 kernel/bpf/verifier.c    | 1 +
 net/core/filter.c        | 6 ++++++
 3 files changed, 8 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index da218fe..913b147 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -95,6 +95,7 @@ enum bpf_prog_type {
 	BPF_PROG_TYPE_SCHED_ACT,
 	BPF_PROG_TYPE_TRACEPOINT,
 	BPF_PROG_TYPE_XDP,
+	BPF_PROG_TYPE_CGROUP_SOCKET_FILTER,
 };
 
 #define BPF_PSEUDO_MAP_FD	1
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f72f23b..3f3164e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1777,6 +1777,7 @@ 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 5708999..c5d8332 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2733,12 +2733,18 @@ 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;
 }
-- 
2.5.5