[PATCH bpf-next 0/5] bpf: Follow up on bpf __sk_buff->tstamp

[PATCH bpf-next 0/5] bpf: Follow up on bpf __sk_buff->tstamp

[Martin KaFai Lau]

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/

Martin KaFai Lau (5):
  bpf: net: Remove TC_AT_INGRESS_OFFSET and
    SKB_MONO_DELIVERY_TIME_OFFSET macro
  bpf: Simplify insn rewrite on BPF_READ __sk_buff->tstamp
  bpf: Simplify insn rewrite on BPF_WRITE __sk_buff->tstamp
  bpf: Remove BPF_SKB_DELIVERY_TIME_NONE and rename
    s/delivery_time_/tstamp_/
  bpf: selftests: Update tests after s/delivery_time/tstamp/ change in
    bpf.h

 include/linux/filter.h                        |   2 +-
 include/linux/skbuff.h                        |  10 +-
 include/uapi/linux/bpf.h                      |  40 +++---
 net/core/filter.c                             | 133 ++++++++----------
 tools/include/uapi/linux/bpf.h                |  40 +++---
 .../selftests/bpf/progs/test_tc_dtime.c       |  38 ++---
 6 files changed, 125 insertions(+), 138 deletions(-)

-- 
2.30.2

[PATCH bpf-next 1/5] bpf: net: Remove TC_AT_INGRESS_OFFSET and SKB_MONO_DELIVERY_TIME_OFFSET macro

[Martin KaFai Lau]

This patch removes the TC_AT_INGRESS_OFFSET and
SKB_MONO_DELIVERY_TIME_OFFSET macros.  Instead, PKT_VLAN_PRESENT_OFFSET
is used because all of them are at the same offset.  Comment is added to
make it clear that changing the position of tc_at_ingress or
mono_delivery_time will require to adjust the defined macros.

The earlier discussion can be found here:
https://lore.kernel.org/bpf/419d994e-ff61-7c11-0ec7-11fefcb0186e@iogearbox.net/

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 include/linux/skbuff.h | 10 +++++-----
 net/core/filter.c      | 14 +++++++-------
 2 files changed, 12 insertions(+), 12 deletions(-)

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/net/core/filter.c b/net/core/filter.c
index 88767f7da150..738a294a3c82 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8896,7 +8896,7 @@ static struct bpf_insn *bpf_convert_dtime_type_read(const struct bpf_insn *si,
 	__u8 tmp_reg = BPF_REG_AX;
 
 	*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg,
-			      SKB_MONO_DELIVERY_TIME_OFFSET);
+			      PKT_VLAN_PRESENT_OFFSET);
 	*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg,
 				SKB_MONO_DELIVERY_TIME_MASK);
 	*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 2);
@@ -8912,7 +8912,7 @@ static struct bpf_insn *bpf_convert_dtime_type_read(const struct bpf_insn *si,
 	*insn++ = BPF_JMP_A(IS_ENABLED(CONFIG_NET_CLS_ACT) ? 6 : 1);
 
 #ifdef CONFIG_NET_CLS_ACT
-	*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, TC_AT_INGRESS_OFFSET);
+	*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, PKT_VLAN_PRESENT_OFFSET);
 	*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg, TC_AT_INGRESS_MASK);
 	*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 2);
 	/* At ingress, value_reg = 0 */
@@ -8959,14 +8959,14 @@ static struct bpf_insn *bpf_convert_tstamp_read(const struct bpf_prog *prog,
 	if (!prog->delivery_time_access) {
 		__u8 tmp_reg = BPF_REG_AX;
 
-		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, TC_AT_INGRESS_OFFSET);
+		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, PKT_VLAN_PRESENT_OFFSET);
 		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg, TC_AT_INGRESS_MASK);
 		*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 5);
 		/* @ingress, read __sk_buff->tstamp as the (rcv) timestamp,
 		 * so check the skb->mono_delivery_time.
 		 */
 		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg,
-				      SKB_MONO_DELIVERY_TIME_OFFSET);
+				      PKT_VLAN_PRESENT_OFFSET);
 		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg,
 					SKB_MONO_DELIVERY_TIME_MASK);
 		*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 2);
@@ -8992,18 +8992,18 @@ static struct bpf_insn *bpf_convert_tstamp_write(const struct bpf_prog *prog,
 	if (!prog->delivery_time_access) {
 		__u8 tmp_reg = BPF_REG_AX;
 
-		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, TC_AT_INGRESS_OFFSET);
+		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, PKT_VLAN_PRESENT_OFFSET);
 		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg, TC_AT_INGRESS_MASK);
 		*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 3);
 		/* Writing __sk_buff->tstamp at ingress as the (rcv) timestamp.
 		 * Clear the skb->mono_delivery_time.
 		 */
 		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg,
-				      SKB_MONO_DELIVERY_TIME_OFFSET);
+				      PKT_VLAN_PRESENT_OFFSET);
 		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg,
 					~SKB_MONO_DELIVERY_TIME_MASK);
 		*insn++ = BPF_STX_MEM(BPF_B, skb_reg, tmp_reg,
-				      SKB_MONO_DELIVERY_TIME_OFFSET);
+				      PKT_VLAN_PRESENT_OFFSET);
 	}
 #endif
 
-- 
2.30.2

[PATCH bpf-next 2/5] bpf: Simplify insn rewrite on BPF_READ __sk_buff->tstamp

[Martin KaFai Lau]

The skb->tc_at_ingress and skb->mono_delivery_time are at the same
byte offset.  Thus, only one BPF_LDX_MEM(BPF_B) is needed
and both bits can be tested together.

/* BPF_READ: a = __sk_buff->tstamp */
if (skb->tc_at_ingress && skb->mono_delivery_time)
	a = 0;
else
	a = skb->tstamp;

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 net/core/filter.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 738a294a3c82..2c83d1f38704 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8956,21 +8956,22 @@ static struct bpf_insn *bpf_convert_tstamp_read(const struct bpf_prog *prog,
 	__u8 skb_reg = si->src_reg;
 
 #ifdef CONFIG_NET_CLS_ACT
+	/* If the delivery_time_type is read,
+	 * the bpf prog is aware the tstamp could have delivery time.
+	 * Thus, read skb->tstamp as is if delivery_time_access is true.
+	 */
 	if (!prog->delivery_time_access) {
+		/* AX is needed because src_reg and dst_reg could be the same */
 		__u8 tmp_reg = BPF_REG_AX;
 
 		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, PKT_VLAN_PRESENT_OFFSET);
-		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg, TC_AT_INGRESS_MASK);
-		*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 5);
-		/* @ingress, read __sk_buff->tstamp as the (rcv) timestamp,
-		 * so check the skb->mono_delivery_time.
-		 */
-		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg,
-				      PKT_VLAN_PRESENT_OFFSET);
 		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg,
-					SKB_MONO_DELIVERY_TIME_MASK);
-		*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 2);
-		/* skb->mono_delivery_time is set, read 0 as the (rcv) timestamp. */
+					TC_AT_INGRESS_MASK | SKB_MONO_DELIVERY_TIME_MASK);
+		*insn++ = BPF_JMP32_IMM(BPF_JNE, tmp_reg,
+					TC_AT_INGRESS_MASK | SKB_MONO_DELIVERY_TIME_MASK, 2);
+		/* skb->tc_at_ingress && skb->mono_delivery_time,
+		 * read 0 as the (rcv) timestamp.
+		 */
 		*insn++ = BPF_MOV64_IMM(value_reg, 0);
 		*insn++ = BPF_JMP_A(1);
 	}
-- 
2.30.2

[PATCH bpf-next 3/5] bpf: Simplify insn rewrite on BPF_WRITE __sk_buff->tstamp

[Martin KaFai Lau]

BPF_JMP32_IMM(BPF_JSET) is used to save a BPF_ALU32_IMM(BPF_AND).

The skb->tc_at_ingress and skb->mono_delivery_time are at the same
offset, so only one BPF_LDX_MEM(BPF_B) is needed.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 net/core/filter.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 2c83d1f38704..f914e4b13b18 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8990,25 +8990,27 @@ static struct bpf_insn *bpf_convert_tstamp_write(const struct bpf_prog *prog,
 	__u8 skb_reg = si->dst_reg;
 
 #ifdef CONFIG_NET_CLS_ACT
+	/* If the delivery_time_type is read,
+	 * the bpf prog is aware the tstamp could have delivery time.
+	 * Thus, write skb->tstamp as is if delivery_time_access is true.
+	 * Otherwise, writing at ingress will have to clear the
+	 * mono_delivery_time bit also.
+	 */
 	if (!prog->delivery_time_access) {
 		__u8 tmp_reg = BPF_REG_AX;
 
 		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, PKT_VLAN_PRESENT_OFFSET);
-		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg, TC_AT_INGRESS_MASK);
-		*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 3);
-		/* Writing __sk_buff->tstamp at ingress as the (rcv) timestamp.
-		 * Clear the skb->mono_delivery_time.
-		 */
-		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg,
-				      PKT_VLAN_PRESENT_OFFSET);
-		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg,
-					~SKB_MONO_DELIVERY_TIME_MASK);
-		*insn++ = BPF_STX_MEM(BPF_B, skb_reg, tmp_reg,
-				      PKT_VLAN_PRESENT_OFFSET);
+		/* Writing __sk_buff->tstamp as ingress, goto <clear> */
+		*insn++ = BPF_JMP32_IMM(BPF_JSET, tmp_reg, TC_AT_INGRESS_MASK, 1);
+		/* goto <store> */
+		*insn++ = BPF_JMP_A(2);
+		/* <clear>: mono_delivery_time */
+		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg, ~SKB_MONO_DELIVERY_TIME_MASK);
+		*insn++ = BPF_STX_MEM(BPF_B, skb_reg, tmp_reg, PKT_VLAN_PRESENT_OFFSET);
 	}
 #endif
 
-	/* skb->tstamp = tstamp */
+	/* <store>: skb->tstamp = tstamp */
 	*insn++ = BPF_STX_MEM(BPF_DW, skb_reg, value_reg,
 			      offsetof(struct sk_buff, tstamp));
 	return insn;
-- 
2.30.2

[PATCH bpf-next 4/5] bpf: Remove BPF_SKB_DELIVERY_TIME_NONE and rename s/delivery_time_/tstamp_/

[Martin KaFai Lau]

This patch is to simplify the uapi bpf.h regarding to the tstamp type
and use a similar way as the kernel to describe the value stored
in __sk_buff->tstamp.

My earlier thought was to avoid describing the semantic and
clock base for the rcv timestamp until there is more clarity
on the use case, so the __sk_buff->delivery_time_type naming instead
of __sk_buff->tstamp_type.

With some thoughts, it can reuse the UNSPEC naming.  This patch first
removes BPF_SKB_DELIVERY_TIME_NONE and also

rename BPF_SKB_DELIVERY_TIME_UNSPEC to BPF_SKB_TSTAMP_UNSPEC
and    BPF_SKB_DELIVERY_TIME_MONO   to BPF_SKB_TSTAMP_DELIVERY_MONO.

The semantic of BPF_SKB_TSTAMP_DELIVERY_MONO is the same:
__sk_buff->tstamp has delivery time in mono clock base.

BPF_SKB_TSTAMP_UNSPEC means __sk_buff->tstamp has the (rcv)
tstamp at ingress and the delivery time at egress.  At egress,
the clock base could be found from skb->sk->sk_clockid.
__sk_buff->tstamp == 0 naturally means NONE, so NONE is not needed.

With BPF_SKB_TSTAMP_UNSPEC for the rcv tstamp at ingress,
the __sk_buff->delivery_time_type is also renamed to __sk_buff->tstamp_type
which was also suggested in the earlier discussion:
https://lore.kernel.org/bpf/b181acbe-caf8-502d-4b7b-7d96b9fc5d55@iogearbox.net/

The above will then make __sk_buff->tstamp and __sk_buff->tstamp_type
the same as its kernel skb->tstamp and skb->mono_delivery_time
counter part.

The internal kernel function bpf_skb_convert_dtime_type_read() is then
renamed to bpf_skb_convert_tstamp_type_read() and it can be simplified
with the BPF_SKB_DELIVERY_TIME_NONE gone.  A BPF_ALU32_IMM(BPF_AND)
insn is also saved by using BPF_JMP32_IMM(BPF_JSET).

The bpf helper bpf_skb_set_delivery_time() is also renamed to
bpf_skb_set_tstamp().  The arg name is changed from dtime
to tstamp also.  It only allows setting tstamp 0 for
BPF_SKB_TSTAMP_UNSPEC and it could be relaxed later
if there is use case to change mono delivery time to
non mono.

prog->delivery_time_access is also renamed to prog->tstamp_type_access.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 include/linux/filter.h         |  2 +-
 include/uapi/linux/bpf.h       | 40 ++++++++--------
 net/core/filter.c              | 88 +++++++++++++---------------------
 tools/include/uapi/linux/bpf.h | 40 ++++++++--------
 4 files changed, 77 insertions(+), 93 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/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 4eebea830613..65871bdbb9c8 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5087,23 +5087,22 @@ 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.
  *
@@ -5116,7 +5115,7 @@ 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),			\
@@ -5311,7 +5310,7 @@ 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
@@ -5502,9 +5501,12 @@ 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.
@@ -5547,7 +5549,7 @@ 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;
 };
diff --git a/net/core/filter.c b/net/core/filter.c
index f914e4b13b18..03655f2074ae 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7388,36 +7388,36 @@ static const struct bpf_func_proto bpf_sock_ops_reserve_hdr_opt_proto = {
 	.arg3_type	= ARG_ANYTHING,
 };
 
-BPF_CALL_3(bpf_skb_set_delivery_time, struct sk_buff *, skb,
-	   u64, dtime, u32, dtime_type)
+BPF_CALL_3(bpf_skb_set_tstamp, struct sk_buff *, skb,
+	   u64, tstamp, u32, tstamp_type)
 {
 	/* skb_clear_delivery_time() is done for inet protocol */
 	if (skb->protocol != htons(ETH_P_IP) &&
 	    skb->protocol != htons(ETH_P_IPV6))
 		return -EOPNOTSUPP;
 
-	switch (dtime_type) {
-	case BPF_SKB_DELIVERY_TIME_MONO:
-		if (!dtime)
+	switch (tstamp_type) {
+	case BPF_SKB_TSTAMP_DELIVERY_MONO:
+		if (!tstamp)
 			return -EINVAL;
-		skb->tstamp = dtime;
+		skb->tstamp = tstamp;
 		skb->mono_delivery_time = 1;
 		break;
-	case BPF_SKB_DELIVERY_TIME_NONE:
-		if (dtime)
+	case BPF_SKB_TSTAMP_UNSPEC:
+		if (tstamp)
 			return -EINVAL;
 		skb->tstamp = 0;
 		skb->mono_delivery_time = 0;
 		break;
 	default:
-		return -EOPNOTSUPP;
+		return -EINVAL;
 	}
 
 	return 0;
 }
 
-static const struct bpf_func_proto bpf_skb_set_delivery_time_proto = {
-	.func           = bpf_skb_set_delivery_time,
+static const struct bpf_func_proto bpf_skb_set_tstamp_proto = {
+	.func           = bpf_skb_set_tstamp,
 	.gpl_only       = false,
 	.ret_type       = RET_INTEGER,
 	.arg1_type      = ARG_PTR_TO_CTX,
@@ -7786,8 +7786,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_tcp_gen_syncookie_proto;
 	case BPF_FUNC_sk_assign:
 		return &bpf_sk_assign_proto;
-	case BPF_FUNC_skb_set_delivery_time:
-		return &bpf_skb_set_delivery_time_proto;
+	case BPF_FUNC_skb_set_tstamp:
+		return &bpf_skb_set_tstamp_proto;
 #endif
 	default:
 		return bpf_sk_base_func_proto(func_id);
@@ -8127,9 +8127,9 @@ static bool bpf_skb_is_valid_access(int off, int size, enum bpf_access_type type
 			return false;
 		info->reg_type = PTR_TO_SOCK_COMMON_OR_NULL;
 		break;
-	case offsetof(struct __sk_buff, delivery_time_type):
+	case offsetof(struct __sk_buff, tstamp_type):
 		return false;
-	case offsetofend(struct __sk_buff, delivery_time_type) ... offsetof(struct __sk_buff, hwtstamp) - 1:
+	case offsetofend(struct __sk_buff, tstamp_type) ... offsetof(struct __sk_buff, hwtstamp) - 1:
 		/* Explicitly prohibit access to padding in __sk_buff. */
 		return false;
 	default:
@@ -8484,14 +8484,14 @@ static bool tc_cls_act_is_valid_access(int off, int size,
 		break;
 	case bpf_ctx_range_till(struct __sk_buff, family, local_port):
 		return false;
-	case offsetof(struct __sk_buff, delivery_time_type):
+	case offsetof(struct __sk_buff, tstamp_type):
 		/* The convert_ctx_access() on reading and writing
 		 * __sk_buff->tstamp depends on whether the bpf prog
-		 * has used __sk_buff->delivery_time_type or not.
-		 * Thus, we need to set prog->delivery_time_access
+		 * has used __sk_buff->tstamp_type or not.
+		 * Thus, we need to set prog->tstamp_type_access
 		 * earlier during is_valid_access() here.
 		 */
-		((struct bpf_prog *)prog)->delivery_time_access = 1;
+		((struct bpf_prog *)prog)->tstamp_type_access = 1;
 		return size == sizeof(__u8);
 	}
 
@@ -8888,42 +8888,22 @@ static u32 flow_dissector_convert_ctx_access(enum bpf_access_type type,
 	return insn - insn_buf;
 }
 
-static struct bpf_insn *bpf_convert_dtime_type_read(const struct bpf_insn *si,
-						    struct bpf_insn *insn)
+static struct bpf_insn *bpf_convert_tstamp_type_read(const struct bpf_insn *si,
+						     struct bpf_insn *insn)
 {
 	__u8 value_reg = si->dst_reg;
 	__u8 skb_reg = si->src_reg;
+	/* AX is needed because src_reg and dst_reg could be the same */
 	__u8 tmp_reg = BPF_REG_AX;
 
 	*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg,
 			      PKT_VLAN_PRESENT_OFFSET);
-	*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg,
-				SKB_MONO_DELIVERY_TIME_MASK);
-	*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 2);
-	/* value_reg = BPF_SKB_DELIVERY_TIME_MONO */
-	*insn++ = BPF_MOV32_IMM(value_reg, BPF_SKB_DELIVERY_TIME_MONO);
-	*insn++ = BPF_JMP_A(IS_ENABLED(CONFIG_NET_CLS_ACT) ? 10 : 5);
-
-	*insn++ = BPF_LDX_MEM(BPF_DW, tmp_reg, skb_reg,
-			      offsetof(struct sk_buff, tstamp));
-	*insn++ = BPF_JMP_IMM(BPF_JNE, tmp_reg, 0, 2);
-	/* value_reg = BPF_SKB_DELIVERY_TIME_NONE */
-	*insn++ = BPF_MOV32_IMM(value_reg, BPF_SKB_DELIVERY_TIME_NONE);
-	*insn++ = BPF_JMP_A(IS_ENABLED(CONFIG_NET_CLS_ACT) ? 6 : 1);
-
-#ifdef CONFIG_NET_CLS_ACT
-	*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, PKT_VLAN_PRESENT_OFFSET);
-	*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg, TC_AT_INGRESS_MASK);
-	*insn++ = BPF_JMP32_IMM(BPF_JEQ, tmp_reg, 0, 2);
-	/* At ingress, value_reg = 0 */
-	*insn++ = BPF_MOV32_IMM(value_reg, 0);
+	*insn++ = BPF_JMP32_IMM(BPF_JSET, tmp_reg,
+				SKB_MONO_DELIVERY_TIME_MASK, 2);
+	*insn++ = BPF_MOV32_IMM(value_reg, BPF_SKB_TSTAMP_UNSPEC);
 	*insn++ = BPF_JMP_A(1);
-#endif
-
-	/* value_reg = BPF_SKB_DELIVERYT_TIME_UNSPEC */
-	*insn++ = BPF_MOV32_IMM(value_reg, BPF_SKB_DELIVERY_TIME_UNSPEC);
+	*insn++ = BPF_MOV32_IMM(value_reg, BPF_SKB_TSTAMP_DELIVERY_MONO);
 
-	/* 15 insns with CONFIG_NET_CLS_ACT */
 	return insn;
 }
 
@@ -8956,11 +8936,11 @@ static struct bpf_insn *bpf_convert_tstamp_read(const struct bpf_prog *prog,
 	__u8 skb_reg = si->src_reg;
 
 #ifdef CONFIG_NET_CLS_ACT
-	/* If the delivery_time_type is read,
+	/* If the tstamp_type is read,
 	 * the bpf prog is aware the tstamp could have delivery time.
-	 * Thus, read skb->tstamp as is if delivery_time_access is true.
+	 * Thus, read skb->tstamp as is if tstamp_type_access is true.
 	 */
-	if (!prog->delivery_time_access) {
+	if (!prog->tstamp_type_access) {
 		/* AX is needed because src_reg and dst_reg could be the same */
 		__u8 tmp_reg = BPF_REG_AX;
 
@@ -8990,13 +8970,13 @@ static struct bpf_insn *bpf_convert_tstamp_write(const struct bpf_prog *prog,
 	__u8 skb_reg = si->dst_reg;
 
 #ifdef CONFIG_NET_CLS_ACT
-	/* If the delivery_time_type is read,
+	/* If the tstamp_type is read,
 	 * the bpf prog is aware the tstamp could have delivery time.
-	 * Thus, write skb->tstamp as is if delivery_time_access is true.
+	 * Thus, write skb->tstamp as is if tstamp_type_access is true.
 	 * Otherwise, writing at ingress will have to clear the
 	 * mono_delivery_time bit also.
 	 */
-	if (!prog->delivery_time_access) {
+	if (!prog->tstamp_type_access) {
 		__u8 tmp_reg = BPF_REG_AX;
 
 		*insn++ = BPF_LDX_MEM(BPF_B, tmp_reg, skb_reg, PKT_VLAN_PRESENT_OFFSET);
@@ -9329,8 +9309,8 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
 			insn = bpf_convert_tstamp_read(prog, si, insn);
 		break;
 
-	case offsetof(struct __sk_buff, delivery_time_type):
-		insn = bpf_convert_dtime_type_read(si, insn);
+	case offsetof(struct __sk_buff, tstamp_type):
+		insn = bpf_convert_tstamp_type_read(si, insn);
 		break;
 
 	case offsetof(struct __sk_buff, gso_segs):
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 4eebea830613..65871bdbb9c8 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5087,23 +5087,22 @@ 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.
  *
@@ -5116,7 +5115,7 @@ 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),			\
@@ -5311,7 +5310,7 @@ 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
@@ -5502,9 +5501,12 @@ 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.
@@ -5547,7 +5549,7 @@ 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;
 };
-- 
2.30.2

[PATCH bpf-next 5/5] bpf: selftests: Update tests after s/delivery_time/tstamp/ change in bpf.h

[Martin KaFai Lau]

The previous patch made the follow changes:
- s/delivery_time_type/tstamp_type/
- s/bpf_skb_set_delivery_time/bpf_skb_set_tstamp/
- BPF_SKB_DELIVERY_TIME_* to BPF_SKB_TSTAMP_*

This patch is to change the test_tc_dtime.c to reflect the above.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 .../selftests/bpf/progs/test_tc_dtime.c       | 38 +++++++++----------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/test_tc_dtime.c b/tools/testing/selftests/bpf/progs/test_tc_dtime.c
index 9d9e8e17b8a0..06f300d06dbd 100644
--- a/tools/testing/selftests/bpf/progs/test_tc_dtime.c
+++ b/tools/testing/selftests/bpf/progs/test_tc_dtime.c
@@ -174,13 +174,13 @@ int egress_host(struct __sk_buff *skb)
 		return TC_ACT_OK;
 
 	if (skb_proto(skb_type) == IPPROTO_TCP) {
-		if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_MONO &&
+		if (skb->tstamp_type == BPF_SKB_TSTAMP_DELIVERY_MONO &&
 		    skb->tstamp)
 			inc_dtimes(EGRESS_ENDHOST);
 		else
 			inc_errs(EGRESS_ENDHOST);
 	} else {
-		if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_UNSPEC &&
+		if (skb->tstamp_type == BPF_SKB_TSTAMP_UNSPEC &&
 		    skb->tstamp)
 			inc_dtimes(EGRESS_ENDHOST);
 		else
@@ -204,7 +204,7 @@ int ingress_host(struct __sk_buff *skb)
 	if (!skb_type)
 		return TC_ACT_OK;
 
-	if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_MONO &&
+	if (skb->tstamp_type == BPF_SKB_TSTAMP_DELIVERY_MONO &&
 	    skb->tstamp == EGRESS_FWDNS_MAGIC)
 		inc_dtimes(INGRESS_ENDHOST);
 	else
@@ -226,7 +226,7 @@ int ingress_fwdns_prio100(struct __sk_buff *skb)
 		return TC_ACT_OK;
 
 	/* delivery_time is only available to the ingress
-	 * if the tc-bpf checks the skb->delivery_time_type.
+	 * if the tc-bpf checks the skb->tstamp_type.
 	 */
 	if (skb->tstamp == EGRESS_ENDHOST_MAGIC)
 		inc_errs(INGRESS_FWDNS_P100);
@@ -250,7 +250,7 @@ int egress_fwdns_prio100(struct __sk_buff *skb)
 		return TC_ACT_OK;
 
 	/* delivery_time is always available to egress even
-	 * the tc-bpf did not use the delivery_time_type.
+	 * the tc-bpf did not use the tstamp_type.
 	 */
 	if (skb->tstamp == INGRESS_FWDNS_MAGIC)
 		inc_dtimes(EGRESS_FWDNS_P100);
@@ -278,9 +278,9 @@ int ingress_fwdns_prio101(struct __sk_buff *skb)
 	if (skb_proto(skb_type) == IPPROTO_UDP)
 		expected_dtime = 0;
 
-	if (skb->delivery_time_type) {
+	if (skb->tstamp_type) {
 		if (fwdns_clear_dtime() ||
-		    skb->delivery_time_type != BPF_SKB_DELIVERY_TIME_MONO ||
+		    skb->tstamp_type != BPF_SKB_TSTAMP_DELIVERY_MONO ||
 		    skb->tstamp != expected_dtime)
 			inc_errs(INGRESS_FWDNS_P101);
 		else
@@ -290,14 +290,14 @@ int ingress_fwdns_prio101(struct __sk_buff *skb)
 			inc_errs(INGRESS_FWDNS_P101);
 	}
 
-	if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_MONO) {
+	if (skb->tstamp_type == BPF_SKB_TSTAMP_DELIVERY_MONO) {
 		skb->tstamp = INGRESS_FWDNS_MAGIC;
 	} else {
-		if (bpf_skb_set_delivery_time(skb, INGRESS_FWDNS_MAGIC,
-					      BPF_SKB_DELIVERY_TIME_MONO))
+		if (bpf_skb_set_tstamp(skb, INGRESS_FWDNS_MAGIC,
+				       BPF_SKB_TSTAMP_DELIVERY_MONO))
 			inc_errs(SET_DTIME);
-		if (!bpf_skb_set_delivery_time(skb, INGRESS_FWDNS_MAGIC,
-					       BPF_SKB_DELIVERY_TIME_UNSPEC))
+		if (!bpf_skb_set_tstamp(skb, INGRESS_FWDNS_MAGIC,
+					BPF_SKB_TSTAMP_UNSPEC))
 			inc_errs(SET_DTIME);
 	}
 
@@ -320,9 +320,9 @@ int egress_fwdns_prio101(struct __sk_buff *skb)
 		/* Should have handled in prio100 */
 		return TC_ACT_SHOT;
 
-	if (skb->delivery_time_type) {
+	if (skb->tstamp_type) {
 		if (fwdns_clear_dtime() ||
-		    skb->delivery_time_type != BPF_SKB_DELIVERY_TIME_MONO ||
+		    skb->tstamp_type != BPF_SKB_TSTAMP_DELIVERY_MONO ||
 		    skb->tstamp != INGRESS_FWDNS_MAGIC)
 			inc_errs(EGRESS_FWDNS_P101);
 		else
@@ -332,14 +332,14 @@ int egress_fwdns_prio101(struct __sk_buff *skb)
 			inc_errs(EGRESS_FWDNS_P101);
 	}
 
-	if (skb->delivery_time_type == BPF_SKB_DELIVERY_TIME_MONO) {
+	if (skb->tstamp_type == BPF_SKB_TSTAMP_DELIVERY_MONO) {
 		skb->tstamp = EGRESS_FWDNS_MAGIC;
 	} else {
-		if (bpf_skb_set_delivery_time(skb, EGRESS_FWDNS_MAGIC,
-					      BPF_SKB_DELIVERY_TIME_MONO))
+		if (bpf_skb_set_tstamp(skb, EGRESS_FWDNS_MAGIC,
+				       BPF_SKB_TSTAMP_DELIVERY_MONO))
 			inc_errs(SET_DTIME);
-		if (!bpf_skb_set_delivery_time(skb, EGRESS_FWDNS_MAGIC,
-					       BPF_SKB_DELIVERY_TIME_UNSPEC))
+		if (!bpf_skb_set_tstamp(skb, INGRESS_FWDNS_MAGIC,
+					BPF_SKB_TSTAMP_UNSPEC))
 			inc_errs(SET_DTIME);
 	}
 
-- 
2.30.2

Re: [PATCH bpf-next 0/5] bpf: Follow up on bpf __sk_buff->tstamp

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Wed, 9 Mar 2022 01:04:44 -0800 you wrote:
> 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.
> 
> [...]

Here is the summary with links:
  - [bpf-next,1/5] bpf: net: Remove TC_AT_INGRESS_OFFSET and SKB_MONO_DELIVERY_TIME_OFFSET macro
    https://git.kernel.org/bpf/bpf-next/c/3b5d4ddf8fe1
  - [bpf-next,2/5] bpf: Simplify insn rewrite on BPF_READ __sk_buff->tstamp
    https://git.kernel.org/bpf/bpf-next/c/539de9328e3a
  - [bpf-next,3/5] bpf: Simplify insn rewrite on BPF_WRITE __sk_buff->tstamp
    https://git.kernel.org/bpf/bpf-next/c/9d90db97e4d4
  - [bpf-next,4/5] bpf: Remove BPF_SKB_DELIVERY_TIME_NONE and rename s/delivery_time_/tstamp_/
    https://git.kernel.org/bpf/bpf-next/c/9bb984f28d5b
  - [bpf-next,5/5] bpf: selftests: Update tests after s/delivery_time/tstamp/ change in bpf.h
    https://git.kernel.org/bpf/bpf-next/c/3daf0896f3f9

You are awesome, thank you!
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