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From: Daniel Borkmann <daniel@iogearbox.net>
To: ast@kernel.org
Cc: daniel@iogearbox.net, john.fastabend@gmail.com,
	netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH bpf-next 1/6] bpf: add classid helper only based on skb->sk
Date: Thu, 24 Sep 2020 20:21:22 +0200	[thread overview]
Message-ID: <2e761d23d591a9536eaa3ecd4be8d78c99f00964.1600967205.git.daniel@iogearbox.net> (raw)
In-Reply-To: <cover.1600967205.git.daniel@iogearbox.net>

Similarly to 5a52ae4e32a6 ("bpf: Allow to retrieve cgroup v1 classid
from v2 hooks"), add a helper to retrieve cgroup v1 classid solely
based on the skb->sk, so it can be used as key as part of BPF map
lookups out of tc from host ns, in particular given the skb->sk is
retained these days when crossing net ns thanks to 9c4c325252c5
("skbuff: preserve sock reference when scrubbing the skb."). This
is similar to bpf_skb_cgroup_id() which implements the same for v2.
Kubernetes ecosystem is still operating on v1 however, hence net_cls
needs to be used there until this can be dropped in with the v2
helper of bpf_skb_cgroup_id().

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 include/uapi/linux/bpf.h       | 10 ++++++++++
 net/core/filter.c              | 21 +++++++++++++++++++++
 tools/include/uapi/linux/bpf.h | 10 ++++++++++
 3 files changed, 41 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index a22812561064..48ecf246d047 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3586,6 +3586,15 @@ union bpf_attr {
  * 		the data in *dst*. This is a wrapper of **copy_from_user**\ ().
  * 	Return
  * 		0 on success, or a negative error in case of failure.
+ *
+ * u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
+ * 	Description
+ * 		See **bpf_get_cgroup_classid**\ () for the main description.
+ * 		This helper differs from **bpf_get_cgroup_classid**\ () in that
+ * 		the cgroup v1 net_cls class is retrieved only from the *skb*'s
+ * 		associated socket instead of the current process.
+ * 	Return
+ * 		The id is returned or 0 in case the id could not be retrieved.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -3737,6 +3746,7 @@ union bpf_attr {
 	FN(inode_storage_delete),	\
 	FN(d_path),			\
 	FN(copy_from_user),		\
+	FN(skb_cgroup_classid),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/net/core/filter.c b/net/core/filter.c
index 6014e5f40c58..0f913755bcba 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2704,6 +2704,23 @@ static const struct bpf_func_proto bpf_get_cgroup_classid_curr_proto = {
 	.gpl_only	= false,
 	.ret_type	= RET_INTEGER,
 };
+
+BPF_CALL_1(bpf_skb_cgroup_classid, const struct sk_buff *, skb)
+{
+	struct sock *sk = skb_to_full_sk(skb);
+
+	if (!sk || !sk_fullsock(sk))
+		return 0;
+
+	return sock_cgroup_classid(&sk->sk_cgrp_data);
+}
+
+static const struct bpf_func_proto bpf_skb_cgroup_classid_proto = {
+	.func		= bpf_skb_cgroup_classid,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+};
 #endif
 
 BPF_CALL_1(bpf_get_cgroup_classid, const struct sk_buff *, skb)
@@ -6770,6 +6787,10 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	case BPF_FUNC_skb_get_xfrm_state:
 		return &bpf_skb_get_xfrm_state_proto;
 #endif
+#ifdef CONFIG_CGROUP_NET_CLASSID
+	case BPF_FUNC_skb_cgroup_classid:
+		return &bpf_skb_cgroup_classid_proto;
+#endif
 #ifdef CONFIG_SOCK_CGROUP_DATA
 	case BPF_FUNC_skb_cgroup_id:
 		return &bpf_skb_cgroup_id_proto;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a22812561064..48ecf246d047 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3586,6 +3586,15 @@ union bpf_attr {
  * 		the data in *dst*. This is a wrapper of **copy_from_user**\ ().
  * 	Return
  * 		0 on success, or a negative error in case of failure.
+ *
+ * u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
+ * 	Description
+ * 		See **bpf_get_cgroup_classid**\ () for the main description.
+ * 		This helper differs from **bpf_get_cgroup_classid**\ () in that
+ * 		the cgroup v1 net_cls class is retrieved only from the *skb*'s
+ * 		associated socket instead of the current process.
+ * 	Return
+ * 		The id is returned or 0 in case the id could not be retrieved.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -3737,6 +3746,7 @@ union bpf_attr {
 	FN(inode_storage_delete),	\
 	FN(d_path),			\
 	FN(copy_from_user),		\
+	FN(skb_cgroup_classid),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
-- 
2.21.0


  reply	other threads:[~2020-09-24 18:21 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-24 18:21 [PATCH bpf-next 0/6] Various BPF helper improvements Daniel Borkmann
2020-09-24 18:21 ` Daniel Borkmann [this message]
2020-09-25 14:46   ` [PATCH bpf-next 1/6] bpf: add classid helper only based on skb->sk Jakub Kicinski
2020-09-25 15:35     ` Daniel Borkmann
2020-09-24 18:21 ` [PATCH bpf-next 2/6] bpf, net: rework cookie generator as per-cpu one Daniel Borkmann
2020-09-24 18:58   ` Eric Dumazet
2020-09-24 22:03     ` Daniel Borkmann
2020-09-25  7:49       ` Eric Dumazet
2020-09-25  9:26         ` Daniel Borkmann
2020-09-25 15:00       ` Jakub Kicinski
2020-09-25 15:15         ` Eric Dumazet
2020-09-25 15:31           ` Jakub Kicinski
2020-09-25 15:45             ` Eric Dumazet
2020-09-24 18:21 ` [PATCH bpf-next 3/6] bpf: add redirect_neigh helper as redirect drop-in Daniel Borkmann
2020-09-24 22:12   ` David Ahern
2020-09-24 22:19     ` Daniel Borkmann
2020-09-24 18:21 ` [PATCH bpf-next 4/6] bpf, libbpf: add bpf_tail_call_static helper for bpf programs Daniel Borkmann
2020-09-24 20:53   ` Andrii Nakryiko
2020-09-24 22:17     ` Daniel Borkmann
2020-09-25 15:42       ` Daniel Borkmann
2020-09-25 15:52         ` Daniel Borkmann
2020-09-25 16:50           ` Andrii Nakryiko
2020-09-25 19:52             ` Daniel Borkmann
2020-09-25  6:13   ` Yonghong Song
2020-09-24 18:21 ` [PATCH bpf-next 5/6] bpf, selftests: use bpf_tail_call_static where appropriate Daniel Borkmann
2020-09-24 19:25   ` Maciej Fijalkowski
2020-09-24 22:03     ` Daniel Borkmann
2020-09-24 18:21 ` [PATCH bpf-next 6/6] bpf, selftests: add redirect_neigh selftest Daniel Borkmann

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