netdev - [PATCH bpf-next 1/2] bpf: add hardware timestamp field to __sk

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Date:   Fri,  3 Sep 2021 01:15:50 +0300
From:   Vadim Fedorenko <vfedorenko@...ek.ru>
To:     Martin KaFai Lau <kafai@...com>
Cc:     Vadim Fedorenko <vfedorenko@...ek.ru>,
        Alexei Starovoitov <ast@...nel.org>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
        bpf@...r.kernel.org
Subject: [PATCH bpf-next 1/2] bpf: add hardware timestamp field to __sk_buff

BPF programs may want to know hardware timestamps if NIC supports
such timestamping.

Expose this data as hwtstamp field of __sk_buff the same way as
gso_segs/gso_size.

Also update BPF_PROG_TEST_RUN tests of the feature.

Signed-off-by: Vadim Fedorenko <vfedorenko@...ek.ru>
---
 include/uapi/linux/bpf.h       |  2 ++
 net/core/filter.c              | 11 +++++++++++
 tools/include/uapi/linux/bpf.h |  2 ++
 3 files changed, 15 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 791f31dd0abe..c7d05b49f557 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5284,6 +5284,8 @@ struct __sk_buff {
 	__u32 gso_segs;
 	__bpf_md_ptr(struct bpf_sock *, sk);
 	__u32 gso_size;
+	__u32 padding;		/* Padding, future use. */
+	__u64 hwtstamp;
 };
 
 struct bpf_tunnel_key {
diff --git a/net/core/filter.c b/net/core/filter.c
index 2e32cee2c469..1d8f8494d325 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8884,6 +8884,17 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type,
 				      si->dst_reg, si->src_reg,
 				      offsetof(struct sk_buff, sk));
 		break;
+	case offsetof(struct __sk_buff, hwtstamp):
+		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_LDX_MEM(BPF_DW,
+				      si->dst_reg, si->dst_reg,
+				      bpf_target_off(struct skb_shared_info,
+						     hwtstamps, 8,
+						     target_size));
+		break;
 	}
 
 	return insn - insn_buf;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 791f31dd0abe..c7d05b49f557 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5284,6 +5284,8 @@ struct __sk_buff {
 	__u32 gso_segs;
 	__bpf_md_ptr(struct bpf_sock *, sk);
 	__u32 gso_size;
+	__u32 padding;		/* Padding, future use. */
+	__u64 hwtstamp;
 };
 
 struct bpf_tunnel_key {
-- 
2.18.4