diff mbox series

[bpf-next,v3,1/2] bpf: add hardware timestamp field to __sk_buff

Message ID 20210909220409.8804-2-vfedorenko@novek.ru (mailing list archive)
State Accepted
Commit f64c4acea51fbe2c08c0b0f48b7f5d1657d7a5e4
Delegated to: BPF
Headers show
Series add hwtstamp to __sk_buff | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for bpf-next
netdev/subject_prefix success Link
netdev/cc_maintainers warning 8 maintainers not CCed: davem@davemloft.net kpsingh@kernel.org haoluo@google.com jackmanb@google.com joe@cilium.io andrii@kernel.org brouer@redhat.com alan.maguire@oracle.com
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 11872 this patch: 11872
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch fail ERROR: space prohibited before that ':' (ctx:WxV) WARNING: line length of 83 exceeds 80 columns WARNING: line length of 87 exceeds 80 columns WARNING: line length of 98 exceeds 80 columns
netdev/build_allmodconfig_warn success Errors and warnings before: 11502 this patch: 11502
netdev/header_inline success Link
bpf/vmtest-bpf-next success VM_Test

Commit Message

Vadim Fedorenko Sept. 9, 2021, 10:04 p.m. UTC 
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 mbox series

Patch

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 {