Subject: [PATCH bpf-next v12 02/12] bpf: prepare the sock_ops ctx and call bpf prog for TX timestamping

From: Jason Xing <[email-masked]>
Date: Tue, 18 Feb 2025 13:01:15 +0800

This patch introduces a new bpf_skops_tx_timestamping() function
that prepares the "struct bpf_sock_ops" ctx and then executes the
sockops BPF program.

The subsequent patch will utilize bpf_skops_tx_timestamping() at
the existing TX timestamping kernel callbacks (__sk_tstamp_tx
specifically) to call the sockops BPF program. Later, four callback
points to report information to user space based on this patch will
be introduced.

Signed-off-by: Jason Xing <[email-masked]>
---
 include/net/sock.h |  7 +++++++
 net/core/sock.c    | 14 ++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/net/sock.h b/include/net/sock.h
index 7916982343c6..6f4d54faba92 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2923,6 +2923,13 @@ int sock_set_timestamping(struct sock *sk, int optname,
 			  struct so_timestamping timestamping);
 
 void sock_enable_timestamps(struct sock *sk);
+#if defined(CONFIG_CGROUP_BPF)
+void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op);
+#else
+static inline void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op)
+{
+}
+#endif
 void sock_no_linger(struct sock *sk);
 void sock_set_keepalive(struct sock *sk);
 void sock_set_priority(struct sock *sk, u32 priority);
diff --git a/net/core/sock.c b/net/core/sock.c
index eae2ae70a2e0..bde45569d4da 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -948,6 +948,20 @@ int sock_set_timestamping(struct sock *sk, int optname,
 	return 0;
 }
 
+#if defined(CONFIG_CGROUP_BPF)
+void bpf_skops_tx_timestamping(struct sock *sk, struct sk_buff *skb, int op)
+{
+	struct bpf_sock_ops_kern sock_ops;
+
+	memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp));
+	sock_ops.op = op;
+	sock_ops.is_fullsock = 1;
+	sock_ops.sk = sk;
+	bpf_skops_init_skb(&sock_ops, skb, 0);
+	__cgroup_bpf_run_filter_sock_ops(sk, &sock_ops, CGROUP_SOCK_OPS);
+}
+#endif
+
 void sock_set_keepalive(struct sock *sk)
 {
 	lock_sock(sk);
-- 
2.43.5