Merge branch 'bpf-tstamp-follow-ups'

Martin KaFai Lau says:

====================
This set is a follow up on the bpf side based on discussion [0].

Patch 1 is to remove some skbuff macros that are used in bpf filter.c.

Patch 2 and 3 are to simplify the bpf insn rewrite on __sk_buff->tstamp.

Patch 4 is to simplify the bpf uapi by modeling the __sk_buff->tstamp
and __sk_buff->tstamp_type (was delivery_time_type) the same as its kernel
counter part skb->tstamp and skb->mono_delivery_time.

Patch 5 is to adjust the bpf selftests due to changes in patch 4.

  [0]: https://lore.kernel.org/bpf/419d994e-ff61-7c11-0ec7-11fefcb0186e@iogearbox.net/
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

3 files changed, 27 insertions, 25 deletions

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 9bf26307247f..05ed9bd31b45 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -573,7 +573,7 @@ struct bpf_prog {
 				enforce_expected_attach_type:1, /* Enforce expected_attach_type checking at attach time */
 				call_get_stack:1, /* Do we call bpf_get_stack() or bpf_get_stackid() */
 				call_get_func_ip:1, /* Do we call get_func_ip() */
-				delivery_time_access:1; /* Accessed __sk_buff->delivery_time_type */
+				tstamp_type_access:1; /* Accessed __sk_buff->tstamp_type */
 	enum bpf_prog_type	type;		/* Type of BPF program */
 	enum bpf_attach_type	expected_attach_type; /* For some prog types */
 	u32			len;		/* Number of filter blocks */
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 2be263184d1e..7b0cb10e70cb 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -960,10 +960,10 @@ struct sk_buff {
 	__u8			csum_complete_sw:1;
 	__u8			csum_level:2;
 	__u8			dst_pending_confirm:1;
-	__u8			mono_delivery_time:1;
+	__u8			mono_delivery_time:1;	/* See SKB_MONO_DELIVERY_TIME_MASK */
 #ifdef CONFIG_NET_CLS_ACT
 	__u8			tc_skip_classify:1;
-	__u8			tc_at_ingress:1;
+	__u8			tc_at_ingress:1;	/* See TC_AT_INGRESS_MASK */
 #endif
 #ifdef CONFIG_IPV6_NDISC_NODETYPE
 	__u8			ndisc_nodetype:2;
@@ -1062,7 +1062,9 @@ struct sk_buff {
 #endif
 #define PKT_TYPE_OFFSET		offsetof(struct sk_buff, __pkt_type_offset)
 
-/* if you move pkt_vlan_present around you also must adapt these constants */
+/* if you move pkt_vlan_present, tc_at_ingress, or mono_delivery_time
+ * around, you also must adapt these constants.
+ */
 #ifdef __BIG_ENDIAN_BITFIELD
 #define PKT_VLAN_PRESENT_BIT	7
 #define TC_AT_INGRESS_MASK		(1 << 0)
@@ -1073,8 +1075,6 @@ struct sk_buff {
 #define SKB_MONO_DELIVERY_TIME_MASK	(1 << 5)
 #endif
 #define PKT_VLAN_PRESENT_OFFSET	offsetof(struct sk_buff, __pkt_vlan_present_offset)
-#define TC_AT_INGRESS_OFFSET offsetof(struct sk_buff, __pkt_vlan_present_offset)
-#define SKB_MONO_DELIVERY_TIME_OFFSET offsetof(struct sk_buff, __pkt_vlan_present_offset)
 
 #ifdef __KERNEL__
 /*
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index bc23020b638d..d288a0a9f797 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5090,23 +5090,22 @@ union bpf_attr {
  *		0 on success, or a negative error in case of failure. On error
  *		*dst* buffer is zeroed out.
  *
- * long bpf_skb_set_delivery_time(struct sk_buff *skb, u64 dtime, u32 dtime_type)
+ * long bpf_skb_set_tstamp(struct sk_buff *skb, u64 tstamp, u32 tstamp_type)
  *	Description
- *		Set a *dtime* (delivery time) to the __sk_buff->tstamp and also
- *		change the __sk_buff->delivery_time_type to *dtime_type*.
+ *		Change the __sk_buff->tstamp_type to *tstamp_type*
+ *		and set *tstamp* to the __sk_buff->tstamp together.
  *
- *		When setting a delivery time (non zero *dtime*) to
- *		__sk_buff->tstamp, only BPF_SKB_DELIVERY_TIME_MONO *dtime_type*
- *		is supported.  It is the only delivery_time_type that will be
- *		kept after bpf_redirect_*().
- *
- *		If there is no need to change the __sk_buff->delivery_time_type,
- *		the delivery time can be directly written to __sk_buff->tstamp
+ *		If there is no need to change the __sk_buff->tstamp_type,
+ *		the tstamp value can be directly written to __sk_buff->tstamp
  *		instead.
  *
- *		*dtime* 0 and *dtime_type* BPF_SKB_DELIVERY_TIME_NONE
- *		can be used to clear any delivery time stored in
- *		__sk_buff->tstamp.
+ *		BPF_SKB_TSTAMP_DELIVERY_MONO is the only tstamp that
+ *		will be kept during bpf_redirect_*().  A non zero
+ *		*tstamp* must be used with the BPF_SKB_TSTAMP_DELIVERY_MONO
+ *		*tstamp_type*.
+ *
+ *		A BPF_SKB_TSTAMP_UNSPEC *tstamp_type* can only be used
+ *		with a zero *tstamp*.
  *
  *		Only IPv4 and IPv6 skb->protocol are supported.
  *
@@ -5119,7 +5118,7 @@ union bpf_attr {
  *	Return
  *		0 on success.
  *		**-EINVAL** for invalid input
- *		**-EOPNOTSUPP** for unsupported delivery_time_type and protocol
+ *		**-EOPNOTSUPP** for unsupported protocol
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -5314,7 +5313,7 @@ union bpf_attr {
 	FN(xdp_load_bytes),		\
 	FN(xdp_store_bytes),		\
 	FN(copy_from_user_task),	\
-	FN(skb_set_delivery_time),      \
+	FN(skb_set_tstamp),		\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
@@ -5505,9 +5504,12 @@ union {					\
 } __attribute__((aligned(8)))
 
 enum {
-	BPF_SKB_DELIVERY_TIME_NONE,
-	BPF_SKB_DELIVERY_TIME_UNSPEC,
-	BPF_SKB_DELIVERY_TIME_MONO,
+	BPF_SKB_TSTAMP_UNSPEC,
+	BPF_SKB_TSTAMP_DELIVERY_MONO,	/* tstamp has mono delivery time */
+	/* For any BPF_SKB_TSTAMP_* that the bpf prog cannot handle,
+	 * the bpf prog should handle it like BPF_SKB_TSTAMP_UNSPEC
+	 * and try to deduce it by ingress, egress or skb->sk->sk_clockid.
+	 */
 };
 
 /* user accessible mirror of in-kernel sk_buff.
@@ -5550,7 +5552,7 @@ struct __sk_buff {
 	__u32 gso_segs;
 	__bpf_md_ptr(struct bpf_sock *, sk);
 	__u32 gso_size;
-	__u8  delivery_time_type;
+	__u8  tstamp_type;
 	__u32 :24;		/* Padding, future use. */
 	__u64 hwtstamp;
 };