[PATCH net-next 3/6] bpf: support bpf_setsockopt for bpf timestamping rx feature

[Jason Xing <kerneljasonxing@gmail.com>]

From: Jason Xing <kernelxing@tencent.com>

Add SK_BPF_CB_RX_TIMESTAMPING callback flag to enable RX timestamping
via bpf_setsockopt(SK_BPF_CB_FLAGS).

Add SOCK_BPF_TIMESTAMPING_RX into enum sock_flags that is used as
centralized management of net_enable/disable_timestamp. Note that only
one of them (timestamp, so_timestamping and bpf timestamping rx) can
enable and disable the global time record of skbs.

In addition, include SOCK_BPF_TIMESTAMPING_RX in SK_FLAGS_TIMESTAMP so
that __sk_destruct() calling sock_disable_timestamp() to thoroughly turn
off the global time record.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
 include/net/sock.h       | 5 ++++-
 include/uapi/linux/bpf.h | 5 +++--
 net/core/filter.c        | 8 ++++++++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index a579d5b09207..cf0e82e46482 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1022,9 +1022,12 @@ enum sock_flags {
 	SOCK_RCVMARK, /* Receive SO_MARK  ancillary data with packet */
 	SOCK_RCVPRIORITY, /* Receive SO_PRIORITY ancillary data with packet */
 	SOCK_TIMESTAMPING_ANY, /* Copy of sk_tsflags & TSFLAGS_ANY */
+	SOCK_BPF_TIMESTAMPING_RX, /* BPF RX timestamping enabled */
 };
 
-#define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
+#define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | \
+			    (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE) | \
+			    (1UL << SOCK_BPF_TIMESTAMPING_RX))
 /*
  * The highest bit of sk_tsflags is reserved for kernel-internal
  * SOCKCM_FLAG_TS_OPT_ID. There is a check in core/sock.c to control that
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 552bc5d9afbd..1e09b5cd7a39 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -7029,8 +7029,9 @@ enum {
 
 enum {
 	SK_BPF_CB_TX_TIMESTAMPING	= 1<<0,
-	SK_BPF_CB_MASK			= (SK_BPF_CB_TX_TIMESTAMPING - 1) |
-					   SK_BPF_CB_TX_TIMESTAMPING
+	SK_BPF_CB_RX_TIMESTAMPING	= 1<<1,
+	SK_BPF_CB_MASK			= (SK_BPF_CB_RX_TIMESTAMPING - 1) |
+					   SK_BPF_CB_RX_TIMESTAMPING
 };
 
 /* List of known BPF sock_ops operators.
diff --git a/net/core/filter.c b/net/core/filter.c
index 9590877b0714..08ad102f204e 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5304,6 +5304,14 @@ static int sk_bpf_set_get_cb_flags(struct sock *sk, char *optval, bool getopt)
 	if (sk_bpf_cb_flags & ~SK_BPF_CB_MASK)
 		return -EINVAL;
 
+	if ((sk_bpf_cb_flags ^ sk->sk_bpf_cb_flags) & SK_BPF_CB_RX_TIMESTAMPING) {
+		if (sk_bpf_cb_flags & SK_BPF_CB_RX_TIMESTAMPING)
+			sock_enable_timestamp(sk, SOCK_BPF_TIMESTAMPING_RX);
+		else
+			sock_disable_timestamp(sk,
+					       (1UL << SOCK_BPF_TIMESTAMPING_RX));
+	}
+
 	sk->sk_bpf_cb_flags = sk_bpf_cb_flags;
 
 	return 0;
-- 
2.43.7