[PATCH bpf-next 0/3] bpf: Add hwtstamp field for the sockops prog

[PATCH bpf-next 0/3] bpf: Add hwtstamp field for the sockops prog

[Martin KaFai Lau]

From: Martin KaFai Lau <martin.lau@kernel.org>

The bpf-tc prog has already been able to access the
skb_hwtstamps(skb)->hwtstamp.  This set extends the same hwtstamp
access to the sockops prog.

Martin KaFai Lau (3):
  bpf: Add hwtstamp field for the sockops prog
  selftests/bpf: Fix incorrect ASSERT in the tcp_hdr_options test
  selftests/bpf: Test skops->skb_hwtstamp

 include/uapi/linux/bpf.h                      |  1 +
 net/core/filter.c                             | 39 +++++++++++++++----
 tools/include/uapi/linux/bpf.h                |  1 +
 .../bpf/prog_tests/tcp_hdr_options.c          |  6 ++-
 .../bpf/progs/test_misc_tcp_hdr_options.c     |  4 ++
 5 files changed, 41 insertions(+), 10 deletions(-)

-- 
2.30.2

[PATCH bpf-next 1/3] bpf: Add hwtstamp field for the sockops prog

[Martin KaFai Lau]

From: Martin KaFai Lau <martin.lau@kernel.org>

The bpf-tc prog has already been able to access the
skb_hwtstamps(skb)->hwtstamp.  This patch extends the same hwtstamp
access to the sockops prog.

In sockops, the skb is also available to the bpf prog during
the BPF_SOCK_OPS_PARSE_HDR_OPT_CB event.  There is a use case
that the hwtstamp will be useful to the sockops prog to better
measure the one-way-delay when the sender has put the tx
timestamp in the tcp header option.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
 include/uapi/linux/bpf.h       |  1 +
 net/core/filter.c              | 39 +++++++++++++++++++++++++++-------
 tools/include/uapi/linux/bpf.h |  1 +
 3 files changed, 33 insertions(+), 8 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 94659f6b3395..fb4c911d2a03 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6445,6 +6445,7 @@ struct bpf_sock_ops {
 				 * the outgoing header has not
 				 * been written yet.
 				 */
+	__u64 skb_hwtstamp;
 };
 
 /* Definitions for bpf_sock_ops_cb_flags */
diff --git a/net/core/filter.c b/net/core/filter.c
index cb3b635e35be..cd667cdbdb26 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8925,6 +8925,10 @@ static bool sock_ops_is_valid_access(int off, int size,
 			bpf_ctx_record_field_size(info, size_default);
 			return bpf_ctx_narrow_access_ok(off, size,
 							size_default);
+		case offsetof(struct bpf_sock_ops, skb_hwtstamp):
+			if (size != sizeof(__u64))
+				return false;
+			break;
 		default:
 			if (size != size_default)
 				return false;
@@ -9108,21 +9112,21 @@ static struct bpf_insn *bpf_convert_tstamp_type_read(const struct bpf_insn *si,
 	return insn;
 }
 
-static struct bpf_insn *bpf_convert_shinfo_access(const struct bpf_insn *si,
+static struct bpf_insn *bpf_convert_shinfo_access(__u8 dst_reg, __u8 skb_reg,
 						  struct bpf_insn *insn)
 {
 	/* si->dst_reg = skb_shinfo(SKB); */
 #ifdef NET_SKBUFF_DATA_USES_OFFSET
 	*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
-			      BPF_REG_AX, si->src_reg,
+			      BPF_REG_AX, skb_reg,
 			      offsetof(struct sk_buff, end));
 	*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, head),
-			      si->dst_reg, si->src_reg,
+			      dst_reg, skb_reg,
 			      offsetof(struct sk_buff, head));
-	*insn++ = BPF_ALU64_REG(BPF_ADD, si->dst_reg, BPF_REG_AX);
+	*insn++ = BPF_ALU64_REG(BPF_ADD, dst_reg, BPF_REG_AX);
 #else
 	*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_buff, end),
-			      si->dst_reg, si->src_reg,
+			      dst_reg, skb_reg,
 			      offsetof(struct sk_buff, end));
 #endif
 
@@ -9515,7 +9519,7 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
 		break;
 
 	case offsetof(struct __sk_buff, gso_segs):
-		insn = bpf_convert_shinfo_access(si, insn);
+		insn = bpf_convert_shinfo_access(si->dst_reg, si->src_reg, insn);
 		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct skb_shared_info, gso_segs),
 				      si->dst_reg, si->dst_reg,
 				      bpf_target_off(struct skb_shared_info,
@@ -9523,7 +9527,7 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
 						     target_size));
 		break;
 	case offsetof(struct __sk_buff, gso_size):
-		insn = bpf_convert_shinfo_access(si, insn);
+		insn = bpf_convert_shinfo_access(si->dst_reg, si->src_reg, insn);
 		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct skb_shared_info, gso_size),
 				      si->dst_reg, si->dst_reg,
 				      bpf_target_off(struct skb_shared_info,
@@ -9550,7 +9554,7 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
 		BUILD_BUG_ON(sizeof_field(struct skb_shared_hwtstamps, hwtstamp) != 8);
 		BUILD_BUG_ON(offsetof(struct skb_shared_hwtstamps, hwtstamp) != 0);
 
-		insn = bpf_convert_shinfo_access(si, insn);
+		insn = bpf_convert_shinfo_access(si->dst_reg, si->src_reg, insn);
 		*insn++ = BPF_LDX_MEM(BPF_DW,
 				      si->dst_reg, si->dst_reg,
 				      bpf_target_off(struct skb_shared_info,
@@ -10400,6 +10404,25 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type,
 						       tcp_flags),
 				      si->dst_reg, si->dst_reg, off);
 		break;
+	case offsetof(struct bpf_sock_ops, skb_hwtstamp): {
+		struct bpf_insn *jmp_on_null_skb;
+
+		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sock_ops_kern,
+						       skb),
+				      si->dst_reg, si->src_reg,
+				      offsetof(struct bpf_sock_ops_kern,
+					       skb));
+		/* Reserve one insn to test skb == NULL */
+		jmp_on_null_skb = insn++;
+		insn = bpf_convert_shinfo_access(si->dst_reg, si->dst_reg, insn);
+		*insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
+				      bpf_target_off(struct skb_shared_info,
+						     hwtstamps, 8,
+						     target_size));
+		*jmp_on_null_skb = BPF_JMP_IMM(BPF_JEQ, si->dst_reg, 0,
+					       insn - jmp_on_null_skb - 1);
+		break;
+	}
 	}
 	return insn - insn_buf;
 }
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 94659f6b3395..fb4c911d2a03 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6445,6 +6445,7 @@ struct bpf_sock_ops {
 				 * the outgoing header has not
 				 * been written yet.
 				 */
+	__u64 skb_hwtstamp;
 };
 
 /* Definitions for bpf_sock_ops_cb_flags */
-- 
2.30.2

[PATCH bpf-next 2/3] selftests/bpf: Fix incorrect ASSERT in the tcp_hdr_options test

[Martin KaFai Lau]

From: Martin KaFai Lau <martin.lau@kernel.org>

This patch fixes the incorrect ASSERT test in tcp_hdr_options during
the CHECK to ASSERT macro cleanup.

Cc: Wang Yufen <wangyufen@huawei.com>
Fixes: 3082f8cd4ba3 ("selftests/bpf: Convert tcp_hdr_options test to ASSERT_* macros")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
 tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
index 617bbce6ef8f..57191773572a 100644
--- a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
+++ b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
@@ -485,7 +485,7 @@ static void misc(void)
 			goto check_linum;
 
 		ret = read(sk_fds.passive_fd, recv_msg, sizeof(recv_msg));
-		if (ASSERT_EQ(ret, sizeof(send_msg), "read(msg)"))
+		if (!ASSERT_EQ(ret, sizeof(send_msg), "read(msg)"))
 			goto check_linum;
 	}
 
@@ -539,7 +539,7 @@ void test_tcp_hdr_options(void)
 		goto skel_destroy;
 
 	cg_fd = test__join_cgroup(CG_NAME);
-	if (ASSERT_GE(cg_fd, 0, "join_cgroup"))
+	if (!ASSERT_GE(cg_fd, 0, "join_cgroup"))
 		goto skel_destroy;
 
 	for (i = 0; i < ARRAY_SIZE(tests); i++) {
-- 
2.30.2

[PATCH bpf-next 3/3] selftests/bpf: Test skops->skb_hwtstamp

[Martin KaFai Lau]

From: Martin KaFai Lau <martin.lau@kernel.org>

This patch tests reading the skops->skb_hwtstamp field.

A local test was also done such that the shinfo hwtstamp was temporary
set to a non zero value in the kernel bpf_skops_parse_hdr()
and the same value can be read by the skops test.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
 tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c      | 2 ++
 tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
index 57191773572a..5cf85d0f9827 100644
--- a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
+++ b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
@@ -505,6 +505,8 @@ static void misc(void)
 
 	ASSERT_EQ(misc_skel->bss->nr_fin, 1, "unexpected nr_fin");
 
+	ASSERT_EQ(misc_skel->bss->nr_hwtstamp, 0, "nr_hwtstamp");
+
 check_linum:
 	ASSERT_FALSE(check_error_linum(&sk_fds), "check_error_linum");
 	sk_fds_close(&sk_fds);
diff --git a/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c b/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c
index 2c121c5d66a7..d487153a839d 100644
--- a/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c
+++ b/tools/testing/selftests/bpf/progs/test_misc_tcp_hdr_options.c
@@ -27,6 +27,7 @@ unsigned int nr_pure_ack = 0;
 unsigned int nr_data = 0;
 unsigned int nr_syn = 0;
 unsigned int nr_fin = 0;
+unsigned int nr_hwtstamp = 0;
 
 /* Check the header received from the active side */
 static int __check_active_hdr_in(struct bpf_sock_ops *skops, bool check_syn)
@@ -146,6 +147,9 @@ static int check_active_hdr_in(struct bpf_sock_ops *skops)
 	if (th->ack && !th->fin && tcp_hdrlen(th) == skops->skb_len)
 		nr_pure_ack++;
 
+	if (skops->skb_hwtstamp)
+		nr_hwtstamp++;
+
 	return CG_OK;
 }
 
-- 
2.30.2