[PATCH net-next v2 02/12] net-timestamp: open gate for bpf_setsockopt

[Jason Xing <kerneljasonxing@gmail.com>]

From: Jason Xing <kernelxing@tencent.com>

For now, we support bpf_setsockopt only TX timestamps flags. Users
can use something like this in bpf program to turn on the feature:

flags = SOF_TIMESTAMPING_TX_SCHED;
bpf_setsockopt(skops, SOL_SOCKET, SO_TIMESTAMPING, &flags, sizeof(flags));

Later, I will support each Tx flags one by one based on this.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
 include/net/sock.h |  2 ++
 net/core/filter.c  | 27 +++++++++++++++++++++++++++
 net/core/sock.c    | 35 ++++++++++++++++++++++++-----------
 3 files changed, 53 insertions(+), 11 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 8cf278c957b3..66ecd78f1dfe 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2890,6 +2890,8 @@ void sock_def_readable(struct sock *sk);
 
 int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk);
 void sock_set_timestamp(struct sock *sk, int optname, bool valbool);
+int sock_get_timestamping(struct so_timestamping *timestamping,
+			  sockptr_t optval, unsigned int optlen);
 int sock_set_timestamping(struct sock *sk, int optname,
 			  struct so_timestamping timestamping);
 
diff --git a/net/core/filter.c b/net/core/filter.c
index bd0d08bf76bb..996426095bd9 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5204,10 +5204,30 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = {
 	.arg1_type      = ARG_PTR_TO_CTX,
 };
 
+static int bpf_sock_set_timestamping(struct sock *sk,
+				     struct so_timestamping *timestamping)
+{
+	u32 flags = timestamping->flags;
+
+	if (flags & ~SOF_TIMESTAMPING_MASK)
+		return -EINVAL;
+
+	if (!(flags & (SOF_TIMESTAMPING_TX_SCHED | SOF_TIMESTAMPING_TX_SOFTWARE |
+	      SOF_TIMESTAMPING_TX_ACK)))
+		return -EINVAL;
+
+	WRITE_ONCE(sk->sk_tsflags[BPFPROG_TS_REQUESTOR], flags);
+
+	return 0;
+}
+
 static int sol_socket_sockopt(struct sock *sk, int optname,
 			      char *optval, int *optlen,
 			      bool getopt)
 {
+	struct so_timestamping ts;
+	int ret = 0;
+
 	switch (optname) {
 	case SO_REUSEADDR:
 	case SO_SNDBUF:
@@ -5225,6 +5245,13 @@ static int sol_socket_sockopt(struct sock *sk, int optname,
 		break;
 	case SO_BINDTODEVICE:
 		break;
+	case SO_TIMESTAMPING_NEW:
+	case SO_TIMESTAMPING_OLD:
+		ret = sock_get_timestamping(&ts, KERNEL_SOCKPTR(optval),
+					    *optlen);
+		if (!ret)
+			ret = bpf_sock_set_timestamping(sk, &ts);
+		return ret;
 	default:
 		return -EINVAL;
 	}
diff --git a/net/core/sock.c b/net/core/sock.c
index 52c8c5a5ba27..a6e0d51a5f72 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -894,6 +894,27 @@ static int sock_timestamping_bind_phc(struct sock *sk, int phc_index)
 	return 0;
 }
 
+int sock_get_timestamping(struct so_timestamping *timestamping,
+			  sockptr_t optval, unsigned int optlen)
+{
+	int val;
+
+	if (copy_from_sockptr(&val, optval, sizeof(val)))
+		return -EFAULT;
+
+	if (optlen == sizeof(*timestamping)) {
+		if (copy_from_sockptr(timestamping, optval,
+				      sizeof(*timestamping))) {
+			return -EFAULT;
+		}
+	} else {
+		memset(timestamping, 0, sizeof(*timestamping));
+		timestamping->flags = val;
+	}
+
+	return 0;
+}
+
 int sock_set_timestamping(struct sock *sk, int optname,
 			  struct so_timestamping timestamping)
 {
@@ -1402,17 +1423,9 @@ int sk_setsockopt(struct sock *sk, int level, int optname,
 
 	case SO_TIMESTAMPING_NEW:
 	case SO_TIMESTAMPING_OLD:
-		if (optlen == sizeof(timestamping)) {
-			if (copy_from_sockptr(&timestamping, optval,
-					      sizeof(timestamping))) {
-				ret = -EFAULT;
-				break;
-			}
-		} else {
-			memset(&timestamping, 0, sizeof(timestamping));
-			timestamping.flags = val;
-		}
-		ret = sock_set_timestamping(sk, optname, timestamping);
+		ret = sock_get_timestamping(&timestamping, optval, optlen);
+		if (!ret)
+			ret = sock_set_timestamping(sk, optname, timestamping);
 		break;
 
 	case SO_RCVLOWAT:
-- 
2.37.3