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From: Daniel Borkmann <daniel@iogearbox.net>
To: alexei.starovoitov@gmail.com
Cc: m@lambda.lt, joe@wand.net.nz, bpf@vger.kernel.org,
	netdev@vger.kernel.org, Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH bpf-next 4/7] bpf: allow to retrieve cgroup v1 classid from v2 hooks
Date: Fri, 27 Mar 2020 16:58:53 +0100
Message-ID: <555e1c69db7376c0947007b4951c260e1074efc3.1585323121.git.daniel@iogearbox.net> (raw)
In-Reply-To: <cover.1585323121.git.daniel@iogearbox.net>

Today, Kubernetes is still operating on cgroups v1, however, it is
possible to retrieve the task's classid based on 'current' out of
connect(), sendmsg(), recvmsg() and bind-related hooks for orchestrators
which attach to the root cgroup v2 hook in a mixed env like in case
of Cilium, for example, in order to then correlate certain pod traffic
and use it as part of the key for BPF map lookups.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 include/net/cls_cgroup.h |  7 ++++++-
 net/core/filter.c        | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/include/net/cls_cgroup.h b/include/net/cls_cgroup.h
index 4295de3e6a4b..7e78e7d6f015 100644
--- a/include/net/cls_cgroup.h
+++ b/include/net/cls_cgroup.h
@@ -45,9 +45,14 @@ static inline void sock_update_classid(struct sock_cgroup_data *skcd)
 	sock_cgroup_set_classid(skcd, classid);
 }
 
+static inline u32 __task_get_classid(struct task_struct *task)
+{
+	return task_cls_state(task)->classid;
+}
+
 static inline u32 task_get_classid(const struct sk_buff *skb)
 {
-	u32 classid = task_cls_state(current)->classid;
+	u32 classid = __task_get_classid(current);
 
 	/* Due to the nature of the classifier it is required to ignore all
 	 * packets originating from softirq context as accessing `current'
diff --git a/net/core/filter.c b/net/core/filter.c
index e249a499cbe5..3083c7746ee0 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2642,6 +2642,19 @@ static const struct bpf_func_proto bpf_msg_pop_data_proto = {
 	.arg4_type	= ARG_ANYTHING,
 };
 
+#ifdef CONFIG_CGROUP_NET_CLASSID
+BPF_CALL_0(bpf_get_cgroup_classid_curr)
+{
+	return __task_get_classid(current);
+}
+
+static const struct bpf_func_proto bpf_get_cgroup_classid_curr_proto = {
+	.func		= bpf_get_cgroup_classid_curr,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+};
+#endif
+
 BPF_CALL_1(bpf_get_cgroup_classid, const struct sk_buff *, skb)
 {
 	return task_get_classid(skb);
@@ -6005,6 +6018,10 @@ sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_get_netns_cookie_sock_proto;
 	case BPF_FUNC_perf_event_output:
 		return &bpf_event_output_data_proto;
+#ifdef CONFIG_CGROUP_NET_CLASSID
+	case BPF_FUNC_get_cgroup_classid:
+		return &bpf_get_cgroup_classid_curr_proto;
+#endif
 	default:
 		return bpf_base_func_proto(func_id);
 	}
@@ -6035,6 +6052,10 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_get_local_storage_proto;
 	case BPF_FUNC_perf_event_output:
 		return &bpf_event_output_data_proto;
+#ifdef CONFIG_CGROUP_NET_CLASSID
+	case BPF_FUNC_get_cgroup_classid:
+		return &bpf_get_cgroup_classid_curr_proto;
+#endif
 #ifdef CONFIG_INET
 	case BPF_FUNC_sk_lookup_tcp:
 		return &bpf_sock_addr_sk_lookup_tcp_proto;
-- 
2.21.0


  parent reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-27 15:58 [PATCH bpf-next 0/7] Various improvements to cgroup helpers Daniel Borkmann
2020-03-27 15:58 ` [PATCH bpf-next 1/7] bpf: enable retrieval of socket cookie for bind/post-bind hook Daniel Borkmann
2020-03-27 15:58 ` [PATCH bpf-next 2/7] bpf: enable perf event rb output for bpf cgroup progs Daniel Borkmann
2020-03-27 15:58 ` [PATCH bpf-next 3/7] bpf: add netns cookie and enable it for bpf cgroup hooks Daniel Borkmann
2020-03-28  0:32   ` Andrii Nakryiko
2020-03-28  1:30     ` Daniel Borkmann
2020-03-28  1:48   ` Alexei Starovoitov
2020-03-28  2:16     ` Daniel Borkmann
2020-03-28  2:56       ` Alexei Starovoitov
2020-03-27 15:58 ` Daniel Borkmann [this message]
2020-03-28  0:41   ` [PATCH bpf-next 4/7] bpf: allow to retrieve cgroup v1 classid from v2 hooks Andrii Nakryiko
2020-03-28  1:56     ` Daniel Borkmann
2020-03-28 20:27       ` Andrii Nakryiko
2020-03-27 15:58 ` [PATCH bpf-next 5/7] bpf: enable bpf cgroup hooks to retrieve cgroup v2 and ancestor id Daniel Borkmann
2020-03-28  0:43   ` Andrii Nakryiko
2020-03-27 15:58 ` [PATCH bpf-next 6/7] bpf: enable retrival of pid/tgid/comm from bpf cgroup hooks Daniel Borkmann
2020-03-28  0:49   ` Andrii Nakryiko
2020-03-28  1:40     ` Daniel Borkmann
2020-03-27 15:58 ` [PATCH bpf-next 7/7] bpf: add selftest cases for ctx_or_null argument type Daniel Borkmann
2020-03-28  0:51   ` Andrii Nakryiko

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