From: Vadim Fedorenko <vfedorenko@novek.ru>
To: Martin KaFai Lau <kafai@fb.com>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: Vadim Fedorenko <vfedorenko@novek.ru>,
Alexei Starovoitov <ast@kernel.org>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH bpf-next v3 1/2] bpf: add hardware timestamp field to __sk_buff
Date: Fri, 10 Sep 2021 01:04:08 +0300 [thread overview]
Message-ID: <20210909220409.8804-2-vfedorenko@novek.ru> (raw)
In-Reply-To: <20210909220409.8804-1-vfedorenko@novek.ru>
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. This field could be accessed from the same
programs as tstamp field, but it's read-only field. Explicit test
to deny access to padding data is added to bpf_skb_is_valid_access.
Also update BPF_PROG_TEST_RUN tests of the feature.
Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
include/uapi/linux/bpf.h | 2 ++
net/core/filter.c | 21 +++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 2 ++
3 files changed, 25 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 791f31dd0abe..51cfd91cc387 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 :32; /* Padding, future use. */
+ __u64 hwtstamp;
};
struct bpf_tunnel_key {
diff --git a/net/core/filter.c b/net/core/filter.c
index 2e32cee2c469..4bace37a6a44 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7765,6 +7765,10 @@ static bool bpf_skb_is_valid_access(int off, int size, enum bpf_access_type type
break;
case bpf_ctx_range_ptr(struct __sk_buff, flow_keys):
return false;
+ case bpf_ctx_range(struct __sk_buff, hwtstamp):
+ if (type == BPF_WRITE || size != sizeof(__u64))
+ return false;
+ break;
case bpf_ctx_range(struct __sk_buff, tstamp):
if (size != sizeof(__u64))
return false;
@@ -7774,6 +7778,9 @@ 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 offsetofend(struct __sk_buff, gso_size) ... offsetof(struct __sk_buff, hwtstamp) - 1:
+ /* Explicitly prohibit access to padding in __sk_buff. */
+ return false;
default:
/* Only narrow read access allowed for now. */
if (type == BPF_WRITE) {
@@ -7802,6 +7809,7 @@ static bool sk_filter_is_valid_access(int off, int size,
case bpf_ctx_range_till(struct __sk_buff, family, local_port):
case bpf_ctx_range(struct __sk_buff, tstamp):
case bpf_ctx_range(struct __sk_buff, wire_len):
+ case bpf_ctx_range(struct __sk_buff, hwtstamp):
return false;
}
@@ -7872,6 +7880,7 @@ static bool lwt_is_valid_access(int off, int size,
case bpf_ctx_range(struct __sk_buff, data_meta):
case bpf_ctx_range(struct __sk_buff, tstamp):
case bpf_ctx_range(struct __sk_buff, wire_len):
+ case bpf_ctx_range(struct __sk_buff, hwtstamp):
return false;
}
@@ -8373,6 +8382,7 @@ static bool sk_skb_is_valid_access(int off, int size,
case bpf_ctx_range(struct __sk_buff, data_meta):
case bpf_ctx_range(struct __sk_buff, tstamp):
case bpf_ctx_range(struct __sk_buff, wire_len):
+ case bpf_ctx_range(struct __sk_buff, hwtstamp):
return false;
}
@@ -8884,6 +8894,17 @@ 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..51cfd91cc387 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 :32; /* Padding, future use. */
+ __u64 hwtstamp;
};
struct bpf_tunnel_key {
--
2.18.4
next prev parent reply other threads:[~2021-09-09 22:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 22:04 [PATCH bpf-next v3 0/2] add hwtstamp to __sk_buff Vadim Fedorenko
2021-09-09 22:04 ` Vadim Fedorenko [this message]
2021-09-09 22:04 ` [PATCH bpf-next v3 2/2] selftests/bpf: test new __sk_buff field hwtstamp Vadim Fedorenko
2021-09-10 21:30 ` [PATCH bpf-next v3 0/2] add hwtstamp to __sk_buff patchwork-bot+netdevbpf
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